GET – GREEN EFFICIENT TECHNOLOGIES EN 2/23

GREEN EFFICIENT TECHNOLOGIES
EN 2/23
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Editorial
European hubris
“The world should recover from the German character” - this well-known saying by the poet Emanuel Geibel from 1861
was originally meant in a completely different way. At present, however, it aptly describes the typical German behaviour
of the missionary desire to teach others coupled with a consistent overestimation of one’s own possibilities and an ideologically
limited view of things. Germany has (fortunately?) had little influence in world politics for decades - but the EU
has now adopted this moralising behaviour in its dealings with the rest of the world.
We are the good guys
This is made clear in an EU press release from 5 October 2023 on the agreement reached on the handling of F-gases,
such as those used in air conditioning systems, refrigeration machines and fire protection systems. The European
Parliament and the EU member states have reached a provisional agreement to tighten the regulations on the use of
fluorinated gases and ozone-depleting substances. Maroš Šefčovič, Executive Vice-President for European Green deal,
Interinstitutional Relations and Foresight, commented as follows on 5 October 2023: „Thanks to the agreement found
today to phase out the F-gases and ozone-depleting substances, we will prevent 32,000 tonnes of ozone-depleting emissions
and save the equivalent of almost 500 million tonnes of CO 2 by 2050. This is excellent news for Europe and for the
world. With F-gases used for air conditioning and refrigeration and demand in this area projected to grow, it is essential
that we make sure these technologies do not exacerbate global warming and that climate-friendly alternatives are
incentivised.“
So far - so good. The Commission elegantly ignored the fact that European refrigeration system manufacturers and
maintenance companies see massive problems and costs looming for themselves and their customers. The following
sentence in the announcement is revealing of the Commission's own mission and assessment of its own importance in
the world: „The Regulation provides incentives to use climate-friendly alternatives, further stimulating the global market
and helping other countries to make the transition as well.“
The other countries will certainly be happy about this. And of course immediately implement what the EU wants.
To be continued
However, this was possibly only the overture for the much larger all-round attack on PFAS restrictions. The ban discussion
initiated by five European environment ministries would have much more serious consequences for European
companies. Global competitors, on the other hand (and probably the environment as a whole), should actually be
pleased about the opportunities for growth if they are allowed to continue using the better plastics.
Showdown in Helsinki
ECHA staff in Helsinki should therefore keep a cool head as they are currently discussing a recommendation to restrict
or even ban PFAS in the EU. Our lead article on the following pages looks at important aspects of these eternal plastics.
Have fun reading.
Ottmar Holz
Editor
GREEN EFFICIENT TECHNOLOGIES 2023
3

GREEN EFFICIENT TECHNOLOGIES
Contents
Cover
Focus on security of supply:
Screw compressors from AERZEN feed biomethane
into the gas network
Security of supply is what counts in the energy industry. For the systems
in use, this results in high demands on availability and reliability.
Whereas smaller power plants, solar farms or wind farms can be
shut down in a relatively simple manner or completely taken off the
network, this is much more difficult with biogas plants. Biological processes
cannot simply be stopped, which is why maximum reliability
and redundancy are required for the technical equipment. EWE NETZ
GmbH uses AERZEN screw compressors to feed biomethane into the
natural gas network for the pre-compression of the biomethane.
Contents
Editorial
European hubris 3
Cover story
Focus on security of supply 6
Leading article
An end to eternity 9
Construction technology
“A universal PFAS ban is not progress in every case” 17
Production organisation
Material flow under clean conditions 20
Energy infrastructure
Strengthening charging infrastructures for electric vehicles
with energy storage systems 23
Cosy warmth from old tunnels 27
Energy effiiency
Reducing air pressure in compressed air systems 30
Hydrogen economy
Dimethyl ether: new transport medium for efficient hydrogen transport 32
The potential of plastic pipes in battery cell production 34
Highly specific safety concepts for hydrogen infrastructures 36
Companies – Innovations – Products 38
Index of Advertisers 39
Brand name register 40
Impressum
Publisher
Dr. Harnisch Verlags GmbH in cooperation with
Prof. (ret.) Dr.-Ing. Eberhard Schlücker, advisor
on hydrogen and energy issues
©
2023, Dr. Harnisch Verlags GmbH
Responsible for content
Ottmar Holz
Silke Watkins
Publishing company and reader service
Dr. Harnisch Verlags GmbH
Eschenstr. 25
90441 Nuremberg, Germany
Tel 0911 2018-0
Fax 0911 2018-100
E-Mail get@harnisch.com
www.harnisch.com
Errors excepted
Reprinting and photomechanical reproduction,even
in extract form, is only possible with
the written consent of the publishers
Editors
Ottmar Holz
Silke Watkins
Advertisements/Brand name register
Silke Watkins/Matti Schneider
Technical Director
Armin König
ISSN 2752-2040
4
GREEN EFFICIENT TECHNOLOGIES 2023

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Cover story
Focus on security of supply
Screw compressors from AERZEN feed biomethane
into the gas network
Sebastian Meißler
Security of supply is what counts in
the energy industry. For the systems
in use, this results in high demands
on availability and reliability.
Whereas smaller power plants, solar
farms or wind farms can be shut
down in a relatively simple manner
or completely taken off the network,
this is much more difficult with biogas
plants. Biological processes cannot
simply be stopped, which is why
maximum reliability and redundancy
are required for the technical
equipment. EWE NETZ GmbH uses
AERZEN screw compressors to feed
biomethane into the natural gas
network for the pre-compression of
the biomethane.
with the direct generation of electricity
from biogas on site in a blocktype
thermal power station, however,
the producer must process the biogas
into biomethane before it can be
fed into the natural gas network. The
local natural gas network operator is
responsible for the feed-in with special
equipment. One functional area
here is pre-compression, for which
EWE NETZ GmbH uses screw compressors
from AERZEN. This process
is divided into two pressure stages.
In the first pressure stage packages
from AERZEN are used, and for the
high pressure range reciprocating
compressors from Neumann and
Esser are used.
Cloppenburg reach the EWE NETZ
GmbH feed-in station every hour at
a transfer pressure of around 100
millibar. “The number of agricultural
businesses is high in this region,”
says Christoph Benten, who is
responsible for biogas feed-in plants
at EWE NETZ. The energy supplier,
which has its headquarters in Oldenburg
does not operate the biogas
plant or the processing plant in the
Processing biogas into biomethane
and feeding it into the natural gas
network: this represents an effective
way of storing the regeneratively
produced energy source. In contrast
Ensuring gas quality
As much as 700 standard cubic
metres of biomethane from a biogas
treatment plant in the district of
Fig. 1: The feed station is installed in a
mobile and space-saving way in a concrete
container directly next to the gas treatment
plant
(All images: AERZEN)
6
GREEN EFFICIENT TECHNOLOGIES 2023

Cover story
district of Cloppenburg. Rather, the
company provides the gas network
and the infrastructure for feed-in. In
this constellation, EWE NETZ GmbH
is responsible for the biomethane
qualities handed over, the necessary
pressure adjustment and the
adjustment of the calorific value for
the safe feed-in of biomethane into
the natural gas network. The guidelines
of the DVGW (German Technical
and Scientific Association for Gas
and Water) must be observed. The
rules and regulations specify, among
other things, the methane content
transferred, the limit values for carbon
dioxide and hydrogen sulphide,
and the water dew point. If the transferred
biomethane remains within
the limits, the pressure is increased
from about 100 millibar to five bar by
means of screw compressors from
AERZEN. The local network itself is
operated at a pressure of between
0.8 and 0.9 bar and supplies the
connected companies and households
with natural gas or injected
bio methane. Christoph Benten: “The
German legislative authority stipulates
that when we feed biomethane
into the natural gas network, we must
achieve a technical availability of the
feed-in plant of at least 96 percent.”
For this reason, EWE NETZ GmbH
maintains a redundant operation
of two identical VMX 110 packages
from AERZEN. Each of these delivers
a capacity of 700 standard cubic
metres per hour. “If one machine
malfunctions, the second machine
automatically takes over.”
Fig. 2: Screw compressors from AERZEN compress the biomethane for feeding into the local
gas network
as the DVGW regulations for use in
Germany.
The screw compressors are
installed in the feed-in plant in the
district of Cloppenburg in a compact
concrete building, which is located
right next to the biogas processing
plant of the biogas plants. The unit
is designed as a ready-to-connect
system that can be put into operation
quickly. “The advantages of the
compact modular design are the
quick and uncomplicated assembling
to another location and the
possibility of being able to dismantle
the system again relatively easily
for moving to another location,”
says Christoph Benten. AERZEN has
delivered the two screw compressors
as a complete system. An important
project participant: Elektrotechnik
GmbH Schaumburg (ELOG). ELOG
was responsible for engineering support
in the area of EMSR technology,
switchgear construction up to commissioning
and the integration of the
system into a higher-level control and
management level. EWE NETZ GmbH
specifies basic engineering and the
definition of interfaces for signal
exchange with the control system for
its sites. Benten: “What matters to us
in this turnkey plant construction is
that the technology used operates
with a high degree of availability and
with few disruptions.”
Approved system solution
Compression of biomethane, biogas
and other mixed hydrocarbon gases:
This is exactly what the oil-lubricated
direct-drive VMX screw compressor
packages are designed for. In five
sizes, the series covers volume flows
of up to 2.500 standard cubic metres
per hour in continuous operation and
delivers a positive pressure of up to
16 bar. For use in the vicinity of biogas
plants, the packages are certified
in accordance with the ATEX directive
2014/34/EU and the machinery directive.
The VMX series meets the latest
safety standards of EN 1012-3 as well
Fig. 3: AERZEN delivered a complete ready-to-install solution for EWE, including piping and
connection to the control level
GREEN EFFICIENT TECHNOLOGIES 2023 7

Cover story
Fig. 4: The VMX screw compressors are rated for maximum availability. What counts, after all, is the security of supply for the feed-in
Different gas qualities
EWE NETZ GmbH uses official calibration
gas analyses to determine
the quality of the biomethane transferred,
and thus verifies the required
limit values in a shutdown matrix. If
the transferred biomethane does not
reach the required transfer parameters,
the feed into the natural gas
network is stopped until the limit values
are met again. As soon as biomethane
is fed into the natural gas
network, EWE NETZ GmbH must
compare the calorific value of the
bio methane transferred with the current
calorific value within the natural
gas network to be fed into and adjust
the bio methane accordingly. There
are two different types of adaptation
(conditioning), which are dependent
on the local natural gas network.
There are currently two calorific value
Fig. 5: With the compression of biomethane,
the renewably produced fuel can
be efficiently fed into existing gas networks
bands within the natural gas networks
in Germany. These are the
L-gas network (low calorific range)
and the H-gas network (high calorific
range). When fed into an L-gas network,
air must be added to the biomethane
to reduce its calorific value.
When feeding into an H-gas network,
the calorific value must again be
increased by adding liquefied petroleum
gas (LPG). The exact dosage of
air or LPG is automatically adjusted
via gas mixers. Projects are currently
underway in Germany and at EWE
NETZ GmbH to convert from L-gas
networks to H-gas networks because
the availability of L-gas is limited.
A further distinction in terms of
feed-in is to be found in the network
into which the gas is fed. The local
distribution network works with a
maximum of 1 bar, the high pressure
network with up to 70 bar. As long as
intake capacities are available within
the local distribution network, the
AERZEN screw compressors feed in.
If a bottleneck occurs, the feed into
the high-pressure network is automatically
activated. Then reciprocating
compressors from Neumann
and Esser take over. The AERZEN
screw compressors remain in operation
and generate the raised intake
pressure for the high-pressure compressors.
This design means that the
reciprocating compressors are only
used for energy reasons when the
local network is no longer absorbing
anything and 70 bar feed pressure is
required.
Biomethane: Renewable energy
in the gas network
The injection of biomethane into
the existing natural gas network
improves the storage possibilities of
biogas and the use of the generated
energy independent of the location
of the biogas plant. Moreover, a time-
related decoupling of generation and
use is possible. With a total length of
530,000 kilometres, the infrastructure
of the natural gas network with
the associated caverns is considered
well developed in Germany. Complete
system solutions for the compression
and injection of gas make
it easier for network operators to
develop new locations.
The Author:
Sebastian Meißler, Marketing
Aerzener Maschinenfabrik GmbH
Reherweg 28
31855 Aerzen, Germany
Tel + 49 5154 81
info@aerzen.com
www.aerzen.com
8
GREEN EFFICIENT TECHNOLOGIES 2023

Photo: Adobe Stock/Octavian
Leading article
An end to eternity
Ottmar Holz
On 22 March 2023, the European
Chemicals Agency (ECHA) published
a proposal for a ban on the manufacture,
use and placing on the
market, including the import of perfluoroalkyl
substances (PFAS). Should
these industrial chemicals with their
special technical properties actually
be banned by the EU Commission
in 2025, this would probably have
far-reaching consequences for many
areas of life - from fried eggs to the
politically mandated energy transition.
PFAS, perfluorinated and polyfluorinated
alkyl substances, are
widely used in almost all areas of life,
from coated pans and outdoor jackets
to glossy business cards. Due to
their distinctive properties such as
high chemical and thermal stability,
non-stick and strong water and oil
repellency, they are widely known
under brand names such as Teflon
and GoreTex.
However, the advantages of these
materials come with disadvantages:
PFAS do not degrade in the environment
and do so for centuries. They
are also highly mobile and can now
be detected worldwide in ground and
surface water, air and soil as well as in
the human bloodstream and in many
living organisms.
They are strongly
suspected of causing
cancer, infertility and
other serious diseases. The toxicity
of some substances in this class of
materials has already been proven.
Despite the long-known problems,
significant steps have only
recently been taken to curb the
spread of PFAS: In November 2022,
the US state of California filed extensive
lawsuits against PFAS-producing
companies such as 3M and Dupont.
Just one month later, 3M became
the first major chemical company to
announce that it would completely
cease production of PFAS substances
by the end of 2025.
PFAS are also ubiquitous in
Europe. A „map of eternal pollution“,
which was created as part of the „Forever
Pollution Project“, illustrates the
extent of the contamination. Journalists
from 18 newspapers and media
houses, including renowned names
such as Le Monde (France), NDR,
WDR, Süddeutsche Zeitung (Germany)
and The Guardian (UK), contributed
to the project.
Against this backdrop, a comprehensive
EU-wide ban on the use
and production of PFAS as a class of
substances was initiated by
Denmark, Germany, the Netherlands,
Norway and Sweden. In
February 2023, the European Chemicals
Agency (ECHA) published the
proposal and is currently reviewing
it before issuing a recommendation
to the European Commission. The
main counter-arguments centre on
the lack of equivalent alternatives for
PFAS in applications considered critical
to society.
From 22 March to 25 September,
the ECHA gave affected companies
and institutions the opportunity
to comment on the proposed restriction
in a consultation process.
According to the ECHA, more than
4,400 organisations, companies and
private individuals submitted more
than 5,600 comments on the topic by
the deadline.
What are PFAS
A PFAS list published by the OECD
in 2018 includes more than 4,700
entries. In addition, there are
unwanted synthesis by-products
Fig. 1: Perfluorooctane sulphonate (PFOS) is one of the most common and most discussed PFAS compounds. Eight fluorinated carbon atoms
(green/black) form the basic structure to which a sulphonic acid group (SO 3 H) is attached.
Graphic: Eurowater
GREEN EFFICIENT TECHNOLOGIES 2023 9

Leading article
and impurities as well as transformation
products that can arise in
the environment both abiotically
and through biodegradation. Potential
degradation products of many
PFAS belong to the extremely persistent
perfluorinated carbon and
sulfonic acids. They can be found
in many things in our everyday
lives: Whether in dental floss, baking
paper, outdoor clothing or extinguishing
and plant protection agents
- PFAS ensure that products everywhere
are water, grease and dirt
repellent. But PFAS are not only useful
as a coating - they can also be
used to produce extremely resistant
plastic bodies and films. These are
used in electrolysers and fuel cells,
for example. What characterises
PFAS for these applications poses a
problem in terms of the disposal of
the chemicals: They are extremely
thermally and chemically stable and
cannot be degraded by light, water
or bacteria.
More than 10,000 different chemicals
are currently the focus of the
restriction process. A generally valid
definition is difficult due to the large
number, one of the possible distinguishing
features is the length of the
carbon chain. Short-chain PFAS with
less than 10 to 13 carbon atoms are
particularly problematic as they dissolve
quite well in water. PFAS can
now be detected in soil, water and
groundwater throughout Europe.
They also end up in our food, and
PFAS can even be found in breast
milk. There are many good reasons
for a ban: Many studies show that
the sometimes toxic chemicals accumulate
in the human body. This has
considerable health effects, ranging
from damage to organs to cancer or
developmental disorders.
Due to their chemical stabili ty,
the elimination of so-called perpetual
chemicals has so far been virtually
impossible with reasonable
effort. Filtering with activated carbon,
for example, binds PFAS but
does not eliminate them, meaning
that the residues have to be disposed
of or stored as hazardous
waste. Activated carbon is also more
suitable for removing long-chain
PFAS.
Who needs these plastics?
Given the ubiquity of these plastics,
it is not possible to even begin to
describe all possible areas of application
within the scope of one article.
However, some sectors in key areas
of industry and the energy transition
would be particularly affected by a
ban. These include electrolyser and
fuel cell manufacturers as well as suppliers
of sealing materials and pump
and compressor manufacturers.
In the current debate, those in
favour of the ban like to argue that
it is necessary to intensify the search
for alternative materials. However,
this could prove difficult in some
areas - because the industry has been
researching for a long time without
success for cheaper and yet equally
high-performance substitutes for
the sometimes extremely expensive
special coatings and sealing materials.
One reason for the long-running,
intensive research into replacements
is the extreme wear resistance of
PFAS. It is based on a very special
physical effect, the tribological film.
Tribology is the science of friction,
lubrication and wear of mechanical
components that move relative to
each other. (You can read about the
special role PFAS play here in the following
article from page 17)
Energy transition on the brink
Energy generation from fossil fuels
must come to an end - most countries
in the world and scientists agree
on this. But how can we fuel all the
blast furnaces, cement works, power
stations and buildings in the world if
natural gas, oil and coal are no longer
an energy source? Hydrogen is the
obvious energy source here. After
all, chemically speaking, only water
is produced during combustion. But
this only applies to hydrogen produced
from water by electrolysis. And
here, too, there is currently no alternative
application for the PFAS substance
group.
Hydrogen fuel cells and electrolysers
play a decisive role in the
urgently needed energy transition.
The central components of both units
are semi-permeable films coated
with special catalyser metals. They
currently consist of perfluorinated
sulphonic acids (PFSA) - a specific
material of the PFAS material class
and are currently used, for example,
in membrane electrode assemblies
(MEAs) of fuel cells due to their
high proton conductivity and chemical
stability. The company ionysis has
set itself the goal of minimising and
completely replacing the use of PFSA
in MEAs.
Also works without fluorine
This start-up from Freiburg, a spinoff
from the „Electrochemical Energy
Systems“ department at Hahn-
Schickard and the University of
Freiburg, is developing more environmentally
friendly and fluorine-free
MEAs without compromising on performance
or costs. In addition, the
focus is on demonstrating technical
feasibility on a relevant scale.
Recently, the team was able to provide
the first successful proof of performance
in heavy-duty full format
and in the short stack. „Together with
national and international partners,
we are pursuing the goal of developing
innovative MEAs for fuel cells,
bringing them to market maturity and
thus making a contribution to a truly
sustainable 'green' hydrogen economy.
Achieving state-of-the-art performance
and validation in the short
stack represents an important milestone
in the early phase of our company,“
says Lisa Langer, co-founder
and CFO of ionysis.
So everything is fine - right?
Not quite as optimistic are practically
all manufacturers of the film material
- such as Chemours, Evonik, Dongyue
and Gore - as well as electrolyser
manufacturers and seal producers.
The editorial team interviewed
H-Tec Systems, a well-known German
electrolyser manufacturer, on behalf
of the company.
GET: Do you see a risk to the energy
transition being promoted by the
German government in the event
of a possible ban on PFAS due to
the lack of equivalent plastics for
10
GREEN EFFICIENT TECHNOLOGIES 2023

Leading article
the production of membranes or
stack seals for electrolysers and
fuel cells?
GET: Does the ban apply worldwide?
Are there similar endeavours
in other countries?
electric drives), the pharmaceutical
and food industries, as well as the
chip and computer industry
H-Tec Systems: A ban on PFAS would
be tantamount to a ban on electrolysis
of all kinds, as there is currently
no economic and technical substitute
with comparable performance. This
would greatly slow down the development
of the hydrogen economy in the
EU and Europe would fall far behind
the USA and China. The transition to
renewable energy and the European
Green Deal would be jeopardised.
As part of the Green Deal, the
EU announced the Circular Economy
Action Plan (CEAP), which includes
measures for electronic and ICT
waste. A recycling regulation for electrolysis
membranes with a high recycling
value could be a viable option.
GET: ECHA ran a consultation procedure
until 21 September in which
citizens, companies and other
organisations can comment on this
proposal. Have you submitted your
concerns to the ECHA?
H-Tec Systems: H-TEC SYSTEMS is taking
part in the ECHA consultation. We
are in close dialogue with our parent
company MAN Energy Solutions and
the VDMA and continue to participate
in a working group of the National
Hydrogen Council on this topic.
Gasket manufacturers and their
customers are also experiencing a
mixture of uncertainty and fear of
disadvantages when trading their
products on the global market. The
gasket specialist C. Otto Gehrckens
GmbH & Co. KG (COG) organised an
online discussion with its customers
over the course of the year and
answered a large number of questions
from users from a wide range
of industries. The GET editorial
team also received some interesting
answers.
GET: Will the ban also affect alternatives
such as fluororubber (FKM)
or perfluororubber (FFKM)?
COG: A general ban would affect all
fluorine-containing qualities such as
FKM, FFKM, FEPM, PTFE or FVMQ.
COG: The PFAS restriction procedure
under discussion is a purely
European procedure. However, similar
PFAS restriction endeavours are
also underway in other countries,
e.g. USA, China, Japan, etc. As far as
we are aware, however, the issue is
being dealt with in a more differentiated
way here and no attempt is
being made to categorically eliminate
PFAS. The perspective on the scope of
PFAS substances is different here. In
Germany, the aim is to achieve a general
ban on the entire PFAS group of
around 10,000 different substances.
In other countries, e.g. the USA or
Japan, only certain PFAS substances
that are proven to be toxic or otherwise
harmful to the environment are
considered in the banning process.
GET: What happens after the ban
or restriction of PFAS in gaskets?
According to you, there is no alternative
to the material.
COG: There is indeed no alternative to
fluoropolymers in some applications.
We are not yet in a position to say
whether and which alternatives will
be developed here. In other applications,
it is possible
to work with
alternatives, but
they do not offer
anywhere
near
the same level
of performance.
This
inevitably
leads to major
technical
setbacks
in many
areas.
GET: Are alternatives currently
being researched?
COG: As fluoro rubbers, especially
FFKM materials, are sometimes very
expensive, research into alternative
materials has been going on for many
years. To date, no substitutes with
comparable performance have been
found. This includes applications for
the energy transition (hydrogen or
GET: Can anything be said about
cost development?
COG: As the substitute materials, if
available at all, generally have a significantly
poorer performance, the
costs will rise accordingly due to
shorter maintenance intervals or
increased failures. These prices will
inevitably be passed on to the (end)
consumer.
GET: There is talk in many places
of alternatives to replace the
PFAS- affected seals. Why are these
alternatives not already in use?
„An indiscriminate ban on
PFAS would be a serious burden
for the market ramp-up
of fuel cells and many other
transformation technologies.“
Gerd Krieger, Managing Director VDMA
e. V. Fuel Cell Working Group
COG: The fact is that the alternatives
currently available do not cover
the same performance spectrum as
fluoroelastomers. It is not only the
excellent chemical resistance with
simultaneous temperature resistance
up to over 300 °C (with an FFKM)
that makes a good FKM or FFKM sealing
material, but also, in combination
with the previous parameters,
the recovery behaviour, the elastic
behaviour over time, etc., that characterise
a high-quality material. It is
usually the case that the frequently
mentioned
extreme
show
substitutes
weaknesses
in one,
often
several
areas. For example,
in some
areas
chemical
where
resistance
is required,
an HNBR compound
can be used instead of an FKM
material. However, this is not the case
if the elastomer seal is also required
to seal at higher temperatures. Or if,
for example in cleaning and sterilisation
processes in the food or pharmaceutical
industry, strongly changing
conditions occur. However, these
requirement profiles are very common
in different industrial sectors.
GET: Are there any overview tables
of currently available alternative
GREEN EFFICIENT TECHNOLOGIES 2023 11

Leading article
materials (for PTFE, FKM, FFKM,
PVDF, ...) in the sealing sector?
COG: COG refers to the in-house
application technology department.
A resistance table (also for alternative
materials) can be found at
https://www.cog.de/produkte/bestaendigkeitsliste.
However, it should
be noted that the resistance values
given there for each type of material
refer to room temperature. At
higher temperatures, the resistance
values can deteriorate considerably.
If in doubt, the user, designer or purchaser
should seek advice from their
gasket supplier or carry out tests.
Most environmental influences occur
during production, i.e. initially on site.
Once a simple fluorine compound
has polymerised into a plastic (e.g.
PTFE), this material can be classified
as non-hazardous in its application.
Its use (and thus its import) will
therefore not be objectionable per se
in the future. It will therefore be up
to the public debate and politicians
in the countries where PFAS are produced
to decide whether their production
will be banned there.
Once released - contaminated
forever?
The interactive "map of eternal pollution"
mentioned at the beginning
of this article lists the known sites of
PFAS pollution throughout Europe. It
is easy to find on https://foreverpollution.eu/maps-and-data/maps/,
for
example. The sites listed are not only
limited to industrial sites; conspicuous
PFAS concentrations can also be
found in many bodies of water and
agricultural areas. The high mobility
of the substances in water also contributes
to this.
On 23 October 2020, the European
Council laid down new minimum
standards for the quality of
drinking water in the revised version
of the EC Drinking Water Directive.
It includes a mandatory risk assessment
and risk management. The
improved monitoring concept also
includes a large number of stricter
limit values for harmful substances,
including PFAS for the first time.
The individual EU member
states transposed this directive into
national law, with Denmark going
one step further and even lowering
the national limit value to 2 nanograms
per litre. On the island of Fanø,
however, the measured value was
significantly higher at 4.4 nanograms.
However, this turned out to be a
problem on the rather small island -
it was not possible to dig another well
on the small island.
Successful pilot project
The solution was provided by the
Danish water treatment specialist
SILHORKO-EUROWATER A/S, part of
the Grundfos Group since 2020. The
Fanø waterworks now has the country's
first water treatment plant that
can remove problematic PFAS substances
from drinking water using
ion exchange technology. The innovative
plant, which consists of a specially
designed filter, can purify up
to 150 m 3 (150,000 litres) of drinking
water per hour. In the system,
the water is passed through a bed
of small ion exchange beads (also
known as resins), which absorb the
PFAS substances.
This purification method not only
reduces the PFAS content to below
the limit value - it is also so effective
that PFAS can no longer be detected
by the measuring devices. In concrete
terms, this means that the content
of each PFAS-4 compound is safely
below a microscopic 0.1 nanogram
per litre, if any is still present at all.
„Our pilot test on Fanø clearly
shows that there is no other purification
method for PFAS that can deliver
comparable results to ion exchange
technology. Both when we talk about
the degree of purification and the
service life,“ says Arne Koch, Head
of the Drinking Water Department at
EUROWATER.
While activated carbon, which
is currently used for the removal of
PFAS, has a short lifespan of just a
few months, the capacity of the resins
is calculated to last for 8-10 years.
Convincing measurements
Fig. 2: Yellow resin instead of black activated carbon: in the ion exchangers from Silhorko/
Eurowater, special resin reliably removes PFAS from the water. Picture: Eurowater/GET
As the plant on Fanø is the first of
its kind, repeated analyses were
required to ensure the quality of the
water before the plant could finally
be put into operation. But the analyses
were clear: no measurable PFAS.
Against this background, the supervisory
authority gave the go-ahead
for the plant to be commissioned
and on 20 March, the residents of
the island of Fanø were able to pour
themselves their first glass of PFASfree
drinking water.
EUROWATER can now use the
experience gained from the Fanø ion
exchange plant to help other waterworks
that may have similar problems
with PFAS.
12
GREEN EFFICIENT TECHNOLOGIES 2023

Leading article
Fig. 3: The resin beads in the ion exchanger ensure clean drinking water for many years.
(Graphic: Eurowater)
„The composition of PFAS substances
can vary from waterworks to waterworks,
but with our knowledge from
Fanø, we are now able to calculate
the degree of purification and
plant capacity as soon as we have
the water analysis in hand,“ says
Søren Duch-Hennings, chemical engineer
and product specialist for ion
exchange technology at EUROWATER.
The water treatment company
has already started the next pilot project,
in which the resins are tested
against a different composition of
PFAS substances.
Plasma flashes break down PFAS
The joint project AtWaPlas, funded
Fig. 4: The special resin beads bind PFAS
to both the hydrophilic functional groups
and the hydrophobic, fluorinated carbon
chains.
(Graphic: Eurowater)
by the Federal Ministry of Education
and Research (BMBF) as part
of the Water N initiative, is taking a
completely different approach to
cleaning PFAS-contaminated water.
The acronym stands for Atmospheric
Water Plasma Treatment.
The energy- efficient process is used
to break down the PFAS molecular
chains so that PFAS can be removed
from contaminated water. The
Fraunhofer Institute for Interfacial
Engineering and Biotechnology IGB
in Stuttgart has developed the process
together with industrial partner
HYDR.O. Geo logen und Ingenieure
from Aachen in just two years. The
process: Circulation of the water in
the plasma reactor
Plasma is an electrically conductive
gas ionised by high voltage, which
is extremely reactive and therefore
able to attack the molecular chains of
substances.
A cylindrical structure is used for
the plasma treatment of contaminated
water. Inside the structure is a
stainless steel cylinder through which
the water is pumped upwards before
flowing down the outside of the
cy linder as a thin film. The stainless
steel cylinder also serves as an earth
electrode for the circuit. The reactor
structure is bounded on the outside
by a glass cylinder on which a copper
mesh is located as a high-voltage electrode.
A tiny gap remains between
the glass cylinder and the water film,
which is filled with a gas mixture. By
applying a voltage of se veral kilovolts
between the two electrodes, a plasma
is generated from the gas mixture. It
is chemically highly active and capable
of breaking molecular bonds. The
plasma is visible to the human eye
due to its characteristic glow and discharge
in the form of flashes.
In the cleaning process, the water
is pumped several times in a closed
circuit through the reactor and the
plasma discharge zone in the gap,
and each time the PFAS molecular
chains are further shortened and
broken down. Ideally, the harmful
PFAS substances are removed in this
way through complete mineralisa-
Fig. 5: Plasma reactor in operation: The
plasma discharges are clearly visible in
the reactor due to the characteristic glow.
(Image: Fraunhofer IGB)
GREEN EFFICIENT TECHNOLOGIES 2023 13

Leading article
more cycles in the tank and to make
the AtWaPlas technology available for
practical application on a larger scale.
In the future, such plants could also
be set up as independent purification
stages in sewage treatment plants or
used in transportable containers on
contaminated open land.
Rescue for the field
Fig. 6: Design of the plasma reactor: A plasma is created by applying a high voltage between
the electrodes. Contaminated water is pumped upwards and flows back downwards in a
gap through the plasma discharge zone. This attacks the PFAS. Graphic: Fraunhofer IGB
tion to such an extent that they are
no longer detectable in mass spectrometric
measurements. This also fulfils
the strict regulations of the Drinking
Water Ordinance with regard to PFAS
concentrations.
Compared to conventional methods
such as filtering with activated
carbon, the technology developed
at the Fraunhofer IGB has a decisive
advantage: Although activated carbon
filters can bind the harmful substances,
they cannot eliminate them.
This means that the filters have to
be replaced and disposed of regularly.
The AtWaPlas technology, on
the other hand, can eliminate the
harmful substances without leaving
any residue and is very efficient and
low-maintenance.
Real water samples instead of
synthetic mixtures
While conventional test methods
work with aqueous PFAS solutions
that are synthetically mixed in the
laboratory, the AtWaPlas project
examined real water samples from
PFAS-contaminated areas, which
were supplied by HYDR.O., a project
partner specialising in the remediation
of contaminated sites. In
addition to PFAS, these also contain
other particles, suspended matter
and organic turbidity. In this way,
the cleaning effect was also demonstrated
under real conditions with
changing water qualities. At the same
time, the process parameters could
be continuously adapted and further
developed.
Further areas of application
and outlook
The plasma water purification process
can also be used to break down
other harmful substances, such as
drug residues, pesticides, herbicides
and cyanides. In addition, AtWaPlas
can also be used for the environmentally
friendly and cost-effective treatment
of drinking water in mobile
applications.
Following the successful series
of tests with a five-litre reactor on
a pilot plant scale, the process is to
be further optimised together with
the collaborative partner. The aim is
to completely eliminate toxic PFAS
through longer process times and
PFAS are not only used as a building
material for plastics or seals - they
can also be found in fire extinguishing
foams. They form a thin film of
water on the surface of flammable
liquids or on molten surfaces and
thus prevent the escape of flammable
gases. This increases the extinguishing
effect of the foam and at the
same time prevents the flammable
liquid from re-igniting. Extinguishing
foams are therefore also traditionally
used at aerodromes. If the extinguishing
water from operations or
the obligatory exercises seeps into
the ground, this can lead to contamination
of neighbouring agricultural
land. But how do you clean a field?
The research consortium of
the FABEKO project, consisting of
GEOlogik Wilbers & Oeder GmbH in
Münster, Mull und Partner Ingenieurgesellschafts
GmbH in Osnabrück,
the Helmholtz Centre for Environmental
Research (UFZ) in Leipzig and
Sensatec GmbH in Kiel, put a remediation
plant for the on-site treatment
of PFAS-contaminated soil
into operation in June 2023. In the
FABEKO research project funded
by the Federal Ministry of Education
and Research (BMBF), the
biopolymer-supported PFAS elution
already tested in the municipality of
Hügelsheim is being further developed
and coupled with two water
treatment processes, flotation and
adsorption of PFAS on electrically
stimulated activated carbon.
To remediate the topsoil, a soil
pile with a volume of 50 m³ was initially
constructed. As already successfully
tested in the previous BioKon
R&D project, the soil is flushed with
a solution of biodegradable solubilisers.
The solubilisers bind the PFAS
and dissolve them from the soil
matrix. The percolate is collected in
14
GREEN EFFICIENT TECHNOLOGIES 2023

Leading article
a pump sump and then conveyed
to the remediation plant where it is
purified.
Regenerating activated carbon
on site
The water treatment process of flotation
has already been used in the
previous research project and is
being further developed in this pilot
trial. The second process, which is
based on the adsorption of PFAS on
electrically stimulated activated carbon
and is considerably more energy
and resource efficient, was developed
by UFZ researchers in this R&D
project. Not only are the trace substances
removed from the water very
efficiently, but the activated carbon
can also be regenerated and reused
directly at the point of use.
For this purpose, fleeces made of
fine activated carbon fibres are used,
the surface of which is tailored to
attract the negatively charged PFAS.
If the absorption capacity of the nonwovens
for PFAS is exhausted, the
activated carbon is briefly negatively
charged, preferably with a green current.
The PFAS molecules, which are
also negatively charged, are repelled
from the surface and collected in a
small volume of concentrate. The
regenerated activated carbon fleece
can then be used again immediately
for water purification.
In the FABEKO project, modules
for potential-controlled adsorption
were developed, which are now
being tested for the first time in
a pilot trial in Rastatt for the purification
of PFAS-containing water
from soil washing. For the pilot test,
a 20" sea container and a 10" sea
container were set up on an agricultural
area near the Hügelsheim
building yard next to the specially
constructed soil pile. The flotation
and dosing unit installed in
the 20" sea container, including
control technology, is used for the
controlled feeding of the biopolymer
solution onto the heap and
the treatment of the process water
by means of flotation. The adsorption
modules are housed in the
adjacent 10" sea container. The
two water treatment processes
can be operated separately or in
series. In addition, several containers
(IBCs) and an activated carbon
filter were placed next to the containers.
A running time of approx.
8 weeks is planned. The joint project
FABEKO (groundwater protection
through extensive treatment of
PFAS-contaminated soils by on-site
soil elution and water treatment
using electro-stimulated activated
carbon) is funded by the Federal
Ministry of Education and Research
(BMBF) under the KMU-innovativ
initiative and technically supported
by the PFAS office of the Rastatt District
Office. KMU-innovativ is part of
the BMBF's "Research for Sustainability
(FONA)" strategy.
The researchers assume that the
soil quality will remain largely intact
after treatment and that microorganisms
and other life forms will
not be negatively affected, as the
biopolymer component is more
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Leading article
Fig. 7: Process diagram of biopolymer-supported PFAS elution and water treatment techniques in the FABEKO project Graphic: Sensatec GmbH
of a source of carbon, i.e. food. In
the course of the current pilot trial,
agricultural parameters that are
intended to provide information
about the quality of the soil are also
being analysed.
Simply grind it up
Another way of destroying PFAS
that is currently being researched
is ball milling. In this process, PFAS
and additives are mixed in a mill at
high speeds with zirconium or stainless
steel balls together with boron
nitride. The collisions between the
balls and the additives are supposed
to lead to solid-state reactions that
destroy the carbon-fluorine bonds
of the PFAS and convert them into
less harmful products. Boron nitride
appears to play a key role in this process.
It appears to take up electrons
and fluorine atoms from the PFAS
in an intermediate step, which then
decompose into fluoroalkyl radicals.
These react with oxygen or other radicals
and ultimately form harmless
minerals.
„A universal PFAS ban is not
progress everywhere“
The PFAS ban could jeopardise the
urgently needed energy transition.
Damage that cannot yet be precisely
quantified has probably already been
caused by the uncertainty among
market players. It can be assumed
that investment decisions regarding
the construction of factories, the
purchase of new machines and the
expansion of production capacities in
the hydrogen sector have been and
will be put on hold until a decision has
been made by the ECHA. In the event
of a ban, there is a risk that an entire
future-oriented industry will move
away. The fact that unfortunately a
lot of shenanigans have been perpetrated
in the past with substances
containing PFAS during use and disposal
must not be allowed to hinder
the urgent reorganisation of our
energy industry. In its statement of 15
September 2023, the National Hydrogen
Council (NWR) recently outlined
what a responsible and differentiated
approach to PFAS could look like.
In this statement, the NWR generally
supports the regulation of perfluorinated
and polyfluorinated alkyl compounds
(PFAS) as well as efforts to
ensure responsible handling to protect
people and the environment.
However, this panel of experts also
considers PFAS to be indispensable
for many key technologies in the
energy transition. A general phaseout
of the use of PFAS could lead to
a de facto blockade, and in any case
to a drastic delay in the ramp-up of
hydrogen technologies, which would
jeopardise the energy transition
and the achievement of the climate
protection goals of the European
Green Deal. Against this backdrop,
the NWR is also calling for a differentiated
risk assessment and categorisation
of the relevant hydrogen
and energy transition technologies
as „essential use“.
The Author: Ottmar Holz
The underlying information
was kindly provided by
(in alphabetical order)
- C. Otto Gehrckens GmbH & Co. KG
- Silhorko/Eurowater
- Sensatec GmbH
- Fraunhofer-Institut für Grenzflächen
und Bioverfahrenstechnik IGB
- H-TEC Systems GmbH
- ionysis GmbH
- Leitstelle Wasserstoff
- Helmholtz-Zentrum für
Umweltforschung GmbH – UFZ
- VDMA - Verband Deutscher
Maschinen- und Anlagenbau e. V.
16
GREEN EFFICIENT TECHNOLOGIES 2023

Construction technology
Sealing technology
PTFE tribofilm cannot be replaced
“A universal PFAS ban is not progress in every case”
Dr. Marc Langela
A ban on PFAS would not only significantly reduce the running times of compressors because the seals wear out more quickly, but would also
ensure that more and more leaks of the fluids to be compressed are released into the environment.
Picture: STASSKOL
Per- and polyfluorinated chemicals
(PFAS) are widely used in industry due
to their unique tribological properties.
However, PFAS are increasingly
being criticized for their environmental
impact and potential health risks,
and more environmentally friendly
alternatives are being sought. However,
a universal ban on PFAS in
industry is proving extremely difficult
and complex and poses enormous
challenges for many industries, as no
alternatives (yet) exist.
The role of tribological film
Tribology is the science of friction,
lubrication and wear of mechanical
components that move relative
to each other. When PFAS are
used, the tribological film, or “tribofilm”
for short, which forms on
the surfaces, plays a decisive role
in the performance of many products.
PFAS, especially the widely used
polytetrafluoroethylene (PTFE), have
a unique molecular structure that
enables exceptionally low friction
between the surfaces and thus also
helps to minimize wear.
When a component made of a perfluorinated
material such as PTFE
comes into contact with a counter
face, the material is deposited on
this counter face in the form of a
thin film. This tribological film (also
known as a transfer film in the literature)
has a thickness in the micrometer
range and protects the surface of
the components. The relative movement
of the surfaces then takes
place between two PTFE or PFAS surfaces,
which leads to a considerable
reduction in friction and wear. Only
when the tribofilm is mechanically
detached from the counter face does
further
wear
occur, as the
detached layer is
replaced by new
material
from
the PTFE component.
This tribological
or transfer film is therefore
the actual reason why components
containing PFAS reduce the frictional
forces and contribute to the surfaces
lasting longer and wearing less. The
tribological film also reduces heat
development and thus supports efficient
energy transfer in machines and
devices.
A ban also jeopardizes
environmental protection
“The special tribological
properties of PFAS plastics are
based on a transfer film that
is unique in this form.”
Dr. Marc Langela, STASSKOL GmbH
A ban on PTFE, for example, would
have serious consequences for the
operation of pumps and compressors,
as not only would the service life
be significantly reduced, but leakages
of the fluids to be compressed would
also be increasingly released into the
environment. Sealing applications for
pumps and compressors (e.g. piston
compressors) have a high load spectrum
consisting
chemical
and
of pressure, friction
speed, temperature
influences.
Only solutions
based on
high-performance polymers can fulfil
this load spectrum.
Tests with a test compressor have
been carried out on the STASSKOL
GmbH test bench for decades. Here,
PTFE-based materials are compared
with formulations of other high-per-
GREEN EFFICIENT TECHNOLOGIES 2023
17

Construction technology
Sealing technology
Fig. 2: Dr. Marc Langela, Head of the
research and development department at
STASSKOL since 2007
formance polymers such as PEEK,
PPS or polyimides. Only perfluorinated
plastics such as PTFE or PFA
achieve minimum leakage and maximum
service life.
The long service life is due to the
formation of the tribofilm described
above, which protects the surfaces
and minimizes wear. But PFAS can
do even more - due to the aliphatic
structure of perfluorinated plastics,
the molecules have a high degree of
flexibility, which is noticeable in the
mouldability of the materials. As a
result, the surfaces of PFAS materials
adapt optimally to a counter face,
even at very high relative speeds.
This enables a sealing efficiency in
dynamically stressed applications
that is inconceivable with alternative
high-performance polymers. The aliphatic
structure of PFAS materials is
created by the carbon-fluorine bond
and protects the polymer backbone.
Alternative
high-performance
polymers such as PEEK, PPS or
polyimides are all based on partially
aromatic structures. These structures
also allow high pressure and temperature
resistance as well as very good
chemical resistance. However, these
high-performance polymers do not
have the ability to form a transfer
film, as is the case with PFAS materials
such as PTFE. This leads to significantly
higher wear, as the tests on
the test compressor have also shown.
While PTFE-based materials (depending
on the load spectrum) enable running
times of approx. 1 to 2 years, this
performance shrinks to a few months
when using high-performance polymers
that do not contain PFAS.
At the same time, the partially
aromatic structure of the alternative
high-performance polymers leads to
high rigidity. In contrast to sealing
solutions based on PFAS plastics, the
rigidity of the alternative high-performance
polymers makes it more
difficult to adapt sealing elements to
the components to be sealed during
relative movement. In the numerous
tests on the test compressor, this led
to an increase in leakages by a factor
of 3-5.
Particularly in the case of compressors
in biogas plants (compression
of methane) or in beverage
factories and breweries (compression
of CO 2 ), such
increases
in
leakages would
lead to a considerable
increase
in
gas
greenhouse
emissions.
The negative effects of a general
ban on PFAS on the environment
are immediately recognisable here.
However, pumps and compressors
are also used in countless chemical
plants where the leakages of process
fluids are burnt off in a flare. Here
too, significantly higher leakages
would lead to a marked increase in
environmental pollution.
In addition to the issue of higher
environmental pollution due to the
increase in greenhouse gases, the
energy efficiency of production processes
also plays a significant role
for the environment. Even if leaks
can be fed back into the process, the
low sealing efficiency of PFAS-free
high-performance polymers leads to
a significant loss of efficiency, which
in turn has to be compensated for
by a higher energy requirement. The
losses of the pump or compressor
must be absorbed and fed back into
the process.
The third point to mention is that
the significantly reduced service life
of the sealing elements means that
shorter maintenance intervals are
required. This leads to increased use
“The issue of using PFAS
plastics is a balancing act between
environmental protection
and responsible use.”
Dr. Marc Langela, STASSKOL GmbH
of materials and personnel in the systems,
a further drop in productivity
due to the resulting downtimes and
other side effects such as increased
travelling by service technicians.
As a result, it is clear that high efficiency
and high availability of pumps
and compressors are an important
component in protecting our environment,
both in standard applications
(biogas, breweries, cork production,
etc.) and in chemical plants such as
refineries or plastics production.
In addition to the issue of higher
environmental pollution due to the
increase in greenhouse gases, the
energy efficiency of production processes
also plays a significant role
for the environment. Even if leaks
can be fed back into the process, the
low sealing efficiency of PFAS-free
high-performance polymers leads
to a significant
loss of efficiency,
which in turn
has to be compensated
for by
a higher energy
requirement. The
losses of the pump or compressor
must be absorbed and fed back into
the process.
The third point to mention is that
the significantly reduced service life
of the sealing elements means that
shorter maintenance intervals are
required. This leads to increased use
of materials and personnel in the systems,
a further drop in productivity
due to the resulting downtimes and
other side effects such as increased
travelling by service technicians.
As a result, it is clear that high efficiency
and high availability of pumps
and compressors are an important
component in protecting our environment,
both in standard applications
(biogas, breweries, cork production,
etc.) and in chemical plants such as
refineries or plastics production.
Weighing up where a PFAS ban
makes sense
One of the biggest challenges is to
find environmentally friendly alternatives
that can adequately mimic
the tribological properties of PFAS.
A substitute material must not only
offer comparable tribological per-
18 GREEN EFFICIENT TECHNOLOGIES 2023

Construction technology
Sealing technology
formance, but also the same resistance
to environmental influences
(e.g. high temperatures, UV, etc.) and
chemicals.
In some applications, PFAS plastics
can be irreplaceable due to their
chemical resistance. These are primarily
the applications in pumps
and compressors described above,
where the parameters add up to a
high load collective. Over the past few
decades, numerous tests have been
carried out with alternative high-performance
polymers. However, the
results in terms of performance
and service life were far behind the
results of PFAS-containing materials.
New solutions with
PFAS-free plastics
The situation is different for applications
with a medium or low load
spectrum. This applies to seals at low
relative speeds and low pressures,
which are used in rotating systems
such as fans, centrifuges, mixers and
similar systems. Solutions based on
PTFE and other PFAS plastics are currently
often used here to be on the
safe side, as these materials really do
guarantee high sealing efficiency and
low wear under all conditions. However,
due to the lower loads in these
applications, PFAS-free plastics would
work just as reliably.
STASSKOL is currently developing
alternatives in order to be able to
dispense with PFAS altogether. In a
moderate temperature range, these
are engineering plastics that are optimized
in terms of friction and wear
by selecting the right fillers and additives.
Tribological characterization
under oscillating and, above all, rotating
motion is the key to success here.
The same applies to applications
in the high-temperature range and
with aggressive media. Here, materials
based on alternative high-performance
polymers without PFAS are
being developed.
So it doesn't always have to be
a PFAS plastic to master the challenges
of the application - it is
important to know when PFAS can
be dispensed with and for which
tasks PFAS plastics are indispensable
- here it is important to push
the boundaries in the direction of
“PFAS-free”.
Recycling instead of a complete ban
The recycling of PFAS materials is
an important step towards protecting
the environment and reducing
the consumption of resources. While
the recycling of thermoplastic materials
has been used in practice for decades,
the recycling of PTFE has always
been considered unfeasible. The reason
for this is the processing of PTFE
in the press-sintering process, as the
high molecular weight means that
plasticizing the materials is not possible.
In the press-sintering process,
the smallest grain sizes are required
(d50 < 50 μm) in order to compact the
material sufficiently and achieve the
target properties.
STASSKOL has been involved in
the recycling of these materials for
around 10 years and has successfully
integrated the process of PTFE
recycling into its production. For this
purpose, waste that accumulates in
the form of chips during the manufacture
of the products is collected
by type and crushed and ground in
a two-stage process. The resulting
powder can be mixed into the virgin
material and fed back into the product
cycle. This significantly increases
the proportion of usable PTFE and,
as a positive side effect, the mechanical
and tribological properties are
even improved by the double heat
treatment compared to pure virgin
material.
Recycling is therefore a viable
solution that enables the availability
of PFAS plastics for demanding applications
and at the same time avoids
environmental pollution.
Conclusion
PFAS-based plastics are simply indispensable
for protecting the environment.
Their outstanding tribological
properties result from the formation
of the so-called tribofilm and
make these materials world champions
in terms of friction and wear. In
addition, the flexible molecular chain
enables an enormously high sealing
efficiency, whereby leakages for
Fig. 1: A piston rod seal whose sealing
elements are made of PFAS plastics can
achieve a service life of 1 to 2 years. With
PFAS-free polymers, it would only be a few
months.
Picture: STASSKOL
the environment can be reduced to a
minimum. These properties are due
to the molecular structure of PFAS
plastics and cannot be imitated by
alternative high-performance polymers.
However, it is important to
understand in which applications
PFAS plastics are irreplaceable and in
which applications substitutes based
on other materials can be used. In
addition, it must be ensured that the
products are disposed of in an environmentally
friendly manner or recycled
at the end of the product life
cycle. STASSKOL has been working
on the recycling of PTFE for years and
has successfully introduced the concept
into production.
It is important to understand that
sealing concepts based on polytetrafluoroethylene
are important building
blocks for future technologies
- such as the hydrogen economy -
and that PFAS plastics make a very
important contribution to environmental
protection in many areas of
industry.
STASSKOL GmbH
Maybachstr. 2
39418 Stassfurt, Germany
www.stasskol.de
GREEN EFFICIENT TECHNOLOGIES 2023
19

Production organisation
Production logistics
Automated guided vehicles for
battery cell production in cleanrooms
Material flow under clean conditions
Gunthart Mau
The electric mobility sector is
booming – and there is an unprecedented
demand for batteries. To
serve this growing market, more
and more battery factories are
currently being built in Europe.
A battery manufacturer based in
northern Europe is using mobile
systems from SEW-EURODRIVE in
its new factory. A particular feature
of these automated guided vehicles
(AGVs) is their special stainless
steel design, which means they can
be used for ISO Class 6 cleanroom
applications, such as for controlled
processes that involve moving
materials in and out of air locks.
For many years now, Asian firms in
particular have been in the lead when
it comes to battery cell production.
The growing demand for lithium-ion
batteries both in the mobility sector
and for stationary applications has
led to rapid growth in this market sector
in recent years – a sector in which
European suppliers urgently need to
catch up. Battery production calls for
system technology that meets stringent
requirements in terms of process
quality and throughput. The key
to this is automation.
The Norwegian mechanical
engineering company Tronrud
Engineering AS specializes in this
field and has been developing, manufacturing,
and supplying automation
solutions for more than 40 years.
Approximately 200 members of staff
work at the company’s Eggemoen and
Moss sites near Oslo. Moss, on the
eastern bank of the Oslofjord, is also
home to the SEW-EURODRIVE Norwegian
subsidiary, SEW-EURODRIVE AS.
Special cleanroom requirements
The end customer, a lithium-ion
battery cell producer, wanted to use
AGVs to automate transport tasks.
However, the design of both the vehicles
themselves and other systems
needed to comply with cleanroom
requirements. Together, Tronrud
and SEW-EURODRIVE implemented
a fully automatic pallet and container
transportation system based
on automated guided vehicles from
the SEW-EURODRIVE MAXOLUTION ®
portfolio.
Using mobile systems in a production
environment with strict cleanroom
requirements and numerous
interfaces, such as elevators, continuous
conveyors, and special-purpose
machines, poses a complex challenge.
Vehicle-to-vehicle transfer in the air
locks involves exacting requirements
in terms of both positioning accuracy
and safety technology. There are also
level changes to deal with (between
the ground floor and an intermediate
level) – and this means transporting
the AGVs, complete with their loads,
in elevators.
From test system to
series production
Fig. 1: SEW-EURODRIVE used its MAXOLUTION ® modular technology system to develop
mobile systems for transportation tasks in cleanrooms and hygienic areas, such as in
battery cell production facilities.
Photo: SEW-EURODRIVE
First of all, a feasibility study was carried
out. This involved installing a
test system in a pilot factory belonging
to the end customer. “Transferring
a load weighing more than
1000 kg from one vehicle to another
was certainly a challenge,” recalls
Cato Horten, senior project manager
at Tronrud Engineering. “However,
thanks to multiple tests and good collaboration,
we were able to come up
with a solution,” he continues. Following
the successful tests, the two companies
worked together to implement
material flow using an automated
guided vehicle system in the series
production facility of a new factory
built on a greenfield site. Skule Edvard
Smørgrav, managing director of Tronrud,
says: “I’d like to emphasize just
how important SEW-EURODRIVE AS is
in Norway. As a key partner, the company
ensured that the right informa-
20 GREEN EFFICIENT TECHNOLOGIES 2023

Production organisation
Production logistics
Fig.2: The platform vehicle with an attached roller conveyor – seen here in the “gray zone” –
can carry a load of more than 1000 kg. Its bidirectional powertrain has a maximum speed
of 1.5 m/s and a positioning accuracy of ±2 to 10 mm.
Photo: SEW-EURODRIVE
tion reached the right people at both
SEW-EURODRIVE Germany and Tronrud
Engineering.”
Two strictly separate AGV zones
Different and distinct routes around
the factory ensure the specified
material flow can be maintained.
There are basically two separate AGV
zones. In what is known as the “gray
zone”, there are no special cleanliness
requirements that the vehicles
need to meet. However, in the "white
zone", the ISO 14644-1 Class 6 cleanroom
requirement applies. When a
load is transferred to the cleanroom
version of the mobile systems, steps
are taken to facilitate clean separation
between the two zones. Loads
are transferred inside special air
locks to prevent cross-contamination.
One main route links the central
warehouse with the production
areas, so that the necessary materials
can be supplied for the process
steps of coating, calendering,
slitting, stacking, and cell assembly.
Other materials are also transported
from the central warehouse environment
to the production department.
Inside the “white” cleanroom zone,
materials are transported right up
to the location where they are used.
They are either delivered directly
or undergo further processes first.
These might include order picking/
sorting and transferring materials
from pallets to individual small load
carriers (SLCs) for temporary storage,
for example, and also involve
transferring the materials from one
vehicle to another. AGVs are additionally
used to transport pallets from the
warehouse to the “supermarket” (a
facility close to the location of use in
production that stores components
ready for use) and from there to the
cell assembly area.
The standardized, interoperable
VDA 5050 communication interface
is used between the fleet manager
and the vehicles. This means an
AGV guidance control system from
a third-party supplier can be used
in this project without any difficulties
whatsoever. In total, 42 AGVs
are being used in the first expansion
stage – 31 vehicles for transporting
pallets and 11 for transporting
SLCs. The longest distance covered is
345 meters, including several elevator
journeys.
Shared responsibility –
and double the customer benefits
Tronrud Engineering is fully responsible
for the stationary and mobile
handling systems for pallets and
containers and has delegated
responsibility for the complete automated
guided vehicle system to
SEW-EURODRIVE. SEW-EURODRIVE
is also responsible for integrating
the Tronrud load handling device on
the vehicle, supplying the complete
vehicle, including the declaration
of conformity, and incorporating
the vehicles into the overall system,
including planning, parameterization,
and startup. Both partners
are providing mutual on-site support
for the startup at the end customer's
premises. What's more, the
European and global presence of
both SEW-EURODRIVE and Tronrud
Engineering will ensure fast, local
support in the future, too.
Hardware and services
Fig. 3: Thanks to innovative navigation and safety technology from SEW-EURODRIVE, loads
can be transferred in air locks reliably and precisely to ensure processes run smoothly.
Photo: SEW-EURODRIVE
SEW-EURODRIVE supplies innovative,
scalable, and future-proof system
solutions in the mobile and
track-guided materials handling technology
sector. The focus is not only
on the vehicles themselves, but also
on the associated services – from
GREEN EFFICIENT TECHNOLOGIES 2023
21

Production organisation
Production logistics
Fig. 4: Mechanical engineering specialist Tronrud Engineering AS develops and produces automation solutions. Its headquarters are located in
Eggemoen to the north-west of Oslo, around a 90-minute drive from the Norwegian capital.
Photo: Tronrud
system planning and simulation to
startup, maintenance, and repair.
In the same way as it uses a
modu lar concept for gearmotors
and electronic products all round the
world, SEW-EURODRIVE also engineers
automated guided vehicle systems
based on an innovative modular
technology and software system. This
modular system makes it possible to
confi gure customized vehicles while
keeping complexity low.
Contactless power supply
Thanks to the SEW-EURODRIVE
MOVITRANS ® energy supply system,
the process for charging the
automated guided vehicles is contactless
and maintenance-free. This
system is therefore particularly suitable
for sensitive areas such as food
production or cleanrooms. There
are various incorporation options
for MOVITRANS ® components that
make simple, decentralized installation
possible. The energy intake system
is wear-free, with charging either
taking place at selected points when
the vehicles are stationary, or while
they are on the move, via line cables
installed in or on the floor. Charging
the vehicles while they are on
the move or during the load transfer
process means that idling time can
be avoided. Consequently, it is possible
to deploy the optimal number
of vehicles for the in-house material
flow. What's more, the system boasts
an automatic energy-saving mode
that helps ensure efficient use of
energy.
Safety technology and navigation
Comprehensive safety technology
provides protection for the entire
vehicle – and, most importantly, for
the people working around it. The
integrated safety controller takes
care of speed-dependent safety
zone switching, Safe Torque Off, safe
speed, and other functions. The load
handling device has also been fully
integrated into the vehicle's safety
system. Laser SLAM (simultaneous
localization and mapping) is used
for navigation around the production
workshops. This, combined with
laser parking and fine positioning by
means of data matrix codes, ensures
vehicles can be positioned with precision
so that processes run reliably.
This is particularly important in safety-relevant
areas, including during
load transfer from one vehicle to
another.
Mobile systems in
battery cell production
SEW-EURODRIVE supplies mobile
systems, drive and control components,
and software from a single
source. Thanks to its modular and
innovative technology system, coupled
with its decades of experience
in many different branches
of industry, the Bruchsal-based
drive automation specialist supplies
innovative and expandable hardware
and software solutions that
are available worldwide. Working
together with mechanical engineering
specialist Tronrud Engineering,
SEW-EURODRIVE installed an automated
guided vehicle system based
on the MAXOLUTION ® portfolio of
mobile transport and assistance systems
in a battery cell production factory
in Europe.
Use of the VDA5050 interface
meant it was easy to use a third-party
supplier's fleet manager in this case.
The system is currently in the final
startup phase. Plans to expand the
AGV fleet are already in the pipeline
and will be implemented in the near
future. The end customer benefits
from the regional presence of Tronrud
Engineering, while both companies
can take advantage of the support
offered by the Norwegian market
organization SEW-EURODRIVE AS in
Moss and the SEW-EURODRIVE headquarters
in Bruchsal.
The Author:
Gunthart Mau, Trade Press Officer,
SEW-EURODRIVE, Bruchsal
22 GREEN EFFICIENT TECHNOLOGIES 2023

Energy infrastructure
Energy storage
Strengthening charging infrastructures for
electric vehicles with energy storage systems
The HES L and HES XXL storage cabinets from Socomec are protected against dust and water ingress in accordance with IP 55 and are therefore
suitable for outdoor installation.
Picture: Socomec
The ban on the sale of combustion
engine vehicles in most European
countries, Canada and some US
states by 2035 is a first step towards
decarbonised road transport.
According to an estimate by the
International Energy Agency (IEA),
350 million electric vehicles will be
on the road by 2030 to achieve the
net zero emissions target by 2050,
which corresponds to more than
60% of vehicles sold worldwide. To
support this growth, it is estimated
that over 60 million charging points
will be installed by 2030.
However, given the rapid growth
and development of fast and superfast
charging stations, the energy
required to charge electric vehicles
is increasing faster than the energy
available on the grid.
Key challenges for the installation
of charging stations:
1. Maintaining the charging speed -
even at peak times
In many places, the electricity grid is
not able to cover the growing electricity
demand of the charging infrastructure
for electric vehicles on its
own. There are two main reasons for
this: the capacity of electricity production
and the available power after the
high/low-voltage transformers. These
may need to be replaced and the
capacity of the power lines also needs
to be increased. The effort and costs
for this are high, especially in cities.
This means that a charging infrastructure
equipped with fast charging
stations may not be able to be supplied
with maximum power during
peak demand periods, reducing the
number of charging sessions per
hour.
If the grid, transformers or lines
are not able to supply the energy
required to operate the charging stations
at rated power, energy storage
systems can provide additional
energy to supply the grid. In this way,
the operating power of the charging
stations can be maximised to enable
the shortest possible charging times.
In this way, the energy storage
system can be charged during periods
of low demand and then discharged
when the power demand of
the electric vehicle charging stations
exceeds the available capacity of the
grid. Thanks to the energy storage
system, it is possible to guarantee a
stable load to ensure the required
charging capacity for electric vehicles
while avoiding the high costs and
long waiting times associated with
upgrading the grid connection.
2. Reduction in operating costs
In some countries, such as Germany,
the energy supply companies calculate
the costs according to the 15
minutes with the highest electricity
consumption. When charging electric
vehicles, consumption peaks can vary
Fig. 1: Grid support: The electricity storage
units cover peak loads (shaded red) that
would exceed the maximum grid capacity
(black line). At times when the load is lower,
the system recharges the storage units.
GREEN EFFICIENT TECHNOLOGIES 2023
23

Energy infrastructure
Energy storage
considerably, as demand can easily
multiply depending on the number
of vehicles charging at the same time.
The integration of energy storage
systems can help to cap the highest
electricity demand through load
control. This technology is known as
peak shaving. In this way, the demand
Fig. 2: Peak shaving through the storage system
peaks normally covered by the grid
are absorbed by the system. The
batteries of the storage system are
charged when the charging demand
for electric vehicles decreases and discharged
when the electricity demand
begins to increase. This reduces the
cost of electricity procurement.
Energy arbitrage
Electricity bills are also determined
by dynamic electricity prices, as the
kilowatt consumed is more expensive
when market demand is high
and cheaper when it is low. This is
often used to encourage a reduction
in consumption at peak times. However,
for an electric vehicle charging
infrastructure, it is not practical in
most cases to reduce consumption
during these periods, as this could
lead to economic losses or insufficient
charging power.
This is where an energy storage
system can be used for energy
arbitrage. The energy for charging the
Fig. 3: Energy arbitrage: During price peaks, for example, the storage system can recharge cars
with cheaply charged electricity at favourable times. This reduces the operating costs of the
vehicle fleet.
vehicles is drawn from the batteries
and not from the grid at times of peak
demand on the market. In this way,
charge/discharge cycles are shifted
by charging or discharging the batteries
when electricity prices are low
or high. As with peak load capping,
this leads to economic savings and
ensures the continuous availability of
the charging line.
3. Optimise your renewable
energy installations
Electric vehicles and renewable
energy installations are real catalysts
for the energy transition, especially
with regard to net zero emission
targets. The integration of renewable
energies such as photovoltaics
(PV) enables the use of an additional
power source to supply the charging
infrastructure. However, renewable
energy is inherently volatile, i.e. its
generation is dependent on weather
conditions and the time of day. As
a result, renewable energy rarely
matches the demand of charging
infrastructure, leading to energy
losses when vehicles are not charging.
By integrating an energy storage
system, this challenge can be overcome
and self-consumption optimised.
The system stores surplus
energy generated by photovoltaic
systems at times of high solar radiation
in order to release it again when
the charging infrastructure has a high
demand for electricity to charge electric
vehicles that cannot be covered
by photovoltaics alone.
Based on the same principle,
energy storage systems also contribute
to the functioning of off-grid
charging infrastructures for electric
vehicles that are combined with the
production of renewable energy. In
areas that are not connected to the
conventional power grid, such a system
can help to ensure a reliable
power supply.
4. Ensuring reliability during
power outages
Fig. 4: EE-Optimisation
The International Energy Agency (IEA)
has already emphasised the risk of
power outages in Europe. It goes
without saying that the resulting load
shedding jeopardises the continuity
of supply to charging infrastructures,
which can lead to interruptions in
charging processes.
The energy storage system can
ensure continuity of supply in the
event of a failure of the main grid, as
24 GREEN EFFICIENT TECHNOLOGIES 2023

HAMPRO® HIGH-PRESSURE
PROCESS TECHNOLOGY
In many production processes in the chemical and petrochemical industry, Hammelmann high-pressure
pumps are the foundation for effective and reliable production.
The high-pressure pumps of the HAMPRO® series are characterized by a robust design, a high safety
standard and careful use of resources.
Our experienced team of experts will be happy to help you configure the right one
high-pressure solution for your process.
RECIPROCATING PUMPS
TO API 674
- Liquid ammonia pumps
- Reactor feed pumps
- Methanol pumps
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Pressure:
50 – 4000 bar
Flow rate: 0,1 – 200 m³/h
TAILOR-MADE AND
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Hammelmann GmbH
(0) 25 22 / 76 - 0
Carl-Zeiss-Straße 6-8
pp@hammelmann.de
D-59302 Oelde www.hammelmann-process.com

Energy infrastructure
Energy storage
Fig. 5: In the event of a power failure,
the storage system can ensure that
the electrically powered vehicle fleet is
ready to drive.
Graphics Fig.1-5: Socomec
it acts as a voltage source. In this way,
the system can supply some loads as
a backup voltage source; depending
on the design of the system, this may
be sufficient to keep the charging
power supply stable until sufficient
grid power is available again.
Socomec energy storage systems
for EVCI
The Socomec energy storage systems
SUNSYS HES L and SUNSYS HES XXL
are the right solutions for the optimal
operation of charging infrastructures
for electric vehicles.
The SUNSYS HES L system with
capacities from 100 kVA/186 kWh to
600 kVA / 1674 kWh and the SUNSYS
HES XXL system with capacities from
1 MVA/1 MWh to 6 MVA/20 MWh are
flexible and can be adapted to various
on-grid and off-grid applications,
including the requirements of
charging infrastructures. They can
also be perfectly integrated into most
charging infrastructures thanks to
their outdoor design.
The systems have been developed
using the best conversion and
battery technologies to meet high
safety standards. They are certified
according to the strictest European
and American standards. Their
design allows for extreme scalability,
enabling them to be adapted to the
design of the infrastructure and the
respective needs.
In addition, commissioning and
maintenance by Socomec’s team of
experts guarantee flawless operation
and an optimised service life of the
system, as well as continuous support
throughout the project.
About SOCOMEC
Since its foundation in 1922,
SOCOMEC has developed into an
independent industrial group with
over 3,900 employees. The group's
speciality: the permanent availabili ty,
monitoring and safety of low-voltage
networks, with a particular focus
on energy efficiency. As an expert in
power management, Socomec manufactures,
among other things, storage
systems equipped with lithium
batteries from CATL. Socomec is a
premium partner of CATL. A total
of twelve production sites in EMEA,
North America and Asia supply 30
branches and trading locations with
goods, meaning that the Socomec
brand is represented in 80 countries.
With a large number of technicians
and spare parts availability,
Socomec scores with short response
times in the event of a service call -
in Germany, for example, the online
response time is a maximum of seven
hours and a technician can be on site
with the necessary spare parts in a
maximum of 24 hours.
Further information:
Socomec GmbH
Erzbergstraße 10
68165 Mannheim, Germany
info.de@socomec.com
www.socomec.de
SUNSYS HES L
SUNSYS HES XXL
Fig. 6 + 7: The HES L and HES XXL energy storage systems have a modular design. Depending on requirements, the user can combine
control and storage cabinets. Both the L and XXL versions of the storage cabinets contain a liquid-cooled CATL EnerOne battery with
lithium iron phosphate technology (LFP).
Pictures: Socomec
26 GREEN EFFICIENT TECHNOLOGIES 2023

Energy infrastructure
Disctrict heating
Cosy warmth from old tunnels
For centuries, coal from the mines
of the Great North Coalfield provided
cosy warmth and the
necessary energy for homes and
factories in the UK. The mines have
long since been exhausted - but
the CO 2 remains. Now heat is once
again flowing out of the tunnels in
Gateshead, which are now full of
groundwater - but this time without
damaging the environment, thanks
to heat pumps from GEA.
Heat energy from the coal mine: The
“Gateshead Mine Water Scheme” is
currently the largest project for heat
recovery from mine water in the UK.
Utilising the energy of the mine water
in the full mine shafts is a comparatively
cost-effective form of geothermal
energy. Only a few boreholes
need to be drilled into the old seams
to tap the heat potential. As a project
partner, GEA supplied two two-stage
high-performance heat pumps with
a total heat output of 6,000 kW. They
utilise the energy from the natu rally
heated mine water to cover the heating
requirements of other buildings
that are to be connected to the existing
local heating network of the specially
founded Gateshead Energy Company.
Since 2018, the municipal heating network
has already been supplying 18
public and private buildings, including
Gateshead College and the Baltic
Arts Centre, several office buildings
and 350 flats. Until now, however, the
heating energy was ge nerated exclusively
by the natural gas-fired combined
heat and power plant that was
built at the time. The new expansion
with the GEA heat pumps provides
an additional twelve GWh of heat per
year. In the near future, a further 270
private households, a conference centre
and a hotel are to be connected
to the district heating network. The
project is expected to save around
72,000 tonnes of CO 2 over its targeted
lifespan of 40 years.
With its striking shape and colour scheme, the combined heat and power plant makes a
strong visual statement in the climate-conscious town of Gateshead, even in bad weather.
Photo: Coal Authority
A pilot project with exemplary
character
Gateshead is located in the northeast
of England near Newcastle. Both
the council and its wholly owned subsidiary
Gateshead Energy Company
(GEC), which operates the Gateshead
District Energy Network (DEN),
have committed to achieving carbon-free
status by 2030. The mine
water heat extraction scheme is part
of Gates head Council's zero carbon
heat stra tegy. The first objective was
to provide cheaper heat energy to all
residents in the borough. The second
aim was to find a complement to the
originally installed combined heat
and power (CHP) system that had a
lower carbon footprint.
Satisfied politicians, grid operators
and authorities
Councillor Martin Gannon, Leader
of Gateshead Borough Council, is
delighted with the success of the
project. He says: “What is happening
here is truly amazing. What we are
seeing in Gateshead is a legacy from
the days of the coal mines. Where
200 years ago we were leading the
industrial revolution, today we are
leading the clean energy revolution.
Working with our partners, we can
utilise naturally heated mine water
to generate valuable, low-carbon
energy. We are proud to have successfully
delivered the largest mine
water project in the UK.”
Richard Bond, Director of Innovation
and Engagement at the Coal
Authority, added: “It's fantastic to
see forward-thinking local authorities
like Gateshead Council utilising
warm mine water to provide low-carbon
heating for buildings. We have
a UK-owned, low-carbon and safe
source of heat from mine water in
Gateshead, which is also an excellent
option for many other communities
in the coalfield. We are delighted that
our support has helped to make this
project a reality.”
Mine water: after “black gold”
now “warm gold”
In the past, the miners in the coal
mine extracted the fossil fuel from
the earth to fire blast furnaces, but
also to heat houses. Gateshead
was once the largest coal supplier
in the world, supplying more than
GREEN EFFICIENT TECHNOLOGIES 2023
27

Energy infrastructure
Disctrict heating
electricity from the grid to run the
heat pumps, which will be produced
with less carbon each year and even
become carbon neutral by the middle
of the next decade. On sunny days,
when GEC has surplus electricity
from the solar parks, these will supply
green energy to run the heat pumps.
This means that GEC can already produce
100 per cent carbon-free heat
for certain periods of time.
GEA ammonia heat pumps offer
optimum performance
Fig. 1: GEA is at the forefront of technological solutions to combat climate change and supply
district heating projects such as this one in the North East of England. GEA heat pumps
are at the centre of the Gateshead Mine Water Scheme, the country's largest mine water heat
recovery system.
Photo: GEA
400,000 tonnes of coal to heat homes
as early as 1625. At peak times, a
quarter of a million miners extracted
up to 56 million tonnes of coal a year
from the tunnels. With the resulting
CO 2 , they unknowingly laid part of the
foundation for today's global warming.
However, the last coal mines in
the region were closed in the 1960s.
Since then, the tunnels have filled
with water, which is now the energy
source for the heat pumps. So once
again the Gateshead underground
is providing vital energy to heat
homes and industry. This time, however,
it does so in an environmentally
friendly way, helping to reduce CO 2
and NOx emissions.
Heat from mine water
The water is pumped from a depth of
150 metres from the old mine into the
operating room at ground level, where
the 2 x 3 MW ammonia heat pumps
from GEA extract the energy from
the 15-degree Celsius mine water. To
optimise the performance of the heat
pump system, GEA uses a two-stage
compression cycle with screw compressors.
The groundwater is filtered
and pumped through titanium plate
and frame heat exchangers. Titanium
was chosen for the evaporator plates
to match the quality of the groundwater.
On the heating side, several
heat exchangers are connected in
series to optimise the efficiency of the
heat pump solution.
The heat pumps increase the temperature
of the operating medium
to produce hot water at up to 80
degrees Celsius. The local heating
network then supplies the connected
houses and buildings in Gateshead
with the energy generated. Once the
heat pumps have extracted the heat
from the mine water, the water is
returned to the mine at a temperature
of eight degrees. According to
the British Coal Authority, this process
ensures a constant water level in
the case of Gateshead and therefore
a long service life. It also eliminates
the need to purify the mine water,
which would be necessary if it were
discharged above ground.
The sun generates the drive current
Part of the concept also includes solar
parks, which help to provide some of
the electricity needed to operate the
heat pumps - these were built on a
field next to the mine water wells and
the heat pump. For every unit of electricity
consumed by the heat pump,
3 units of renewable heat are generated.
This corresponds to a COP
of 3. The operator GEC will import
Large heat pumps are usually customised
for the project in question.
The developers at GEA chose ammonia
as the natural refrigerant for this
application. It offers the best efficiency
and has no global warming
potential. Under the given conditions
in Gateshead, ammonia heat pumps
are 10 to 20 per cent more efficient
than F-gas solutions (HFC/HFO).
GEA with extensive
experience in heat pumps and
district heating projects
GEA has been involved in other innovative
district heating heat pump
projects in the UK in the past, including
the installation of a heat pump
that extracts heat from the London
Underground's ventilation air to provide
heat to a tower block in Islington.
John Burden, Director Project
Sales Heating & Refrigeration Solutions
at GEA UK, says: “GEA's highly
innovative heat pump technology
has already been used in other district
heating projects in the UK and
around the world as we recognise the
dire consequences of global warming.
With the UK Government's ambitious
targets to significantly increase
the proportion of district heating in
the UK, we expect to see many more
new and ambitious projects in the
coming years.”
According to the British Coal
Authority, one of these will be the
mine water treatment plant in Dawdon.
It will supply up to 1.5 megawatts
of heat to a new heat network
that currently covers up to 1,250
homes in a project led by Durham
County Council.
28 GREEN EFFICIENT TECHNOLOGIES 2023

Energy infrastructure
Disctrict heating
Fig. 2: The CHP plant extracts warm mine water from two boreholes (JC5 +1a) from the "Hutton" seam at a depth of 147 metres. The cooled
water is fed back into the 35 metre deep "High Main" seam via borehole JC3. It sinks back into the depths in the JC12 relief shaft.
Graphics: The Coal Authority
The Coal Authority has around 70
sites across the UK where mine water
is pumped to the surface or drains
away naturally. It treats these as part
of its statutory duty in the environmental
projection of watercourses
and aquifers for public water supplies
(similar to the Ruhr area in Germany).
In the last financial year, the Coal
Authority says it created the capacity
to treat 220 billion litres of mine
water. This waste water is also being
considered as a source of heat.
According to RAG Aktiengesellschaft,
it is conducting feasibili ty
studies at all of RAG’s mine water
sites. However, for subsidy law reasons,
RAG is not permitted to utilise
the mine water for thermal purposes
on the market. In this case, RAG is
dependent on co-operation with
others, to whom RAG will then make
the mine water available for use. To
this end, RAG is in talks with a number
of municipalities that already
have the necessary district heating
pipelines. An additional complication
is the hydrological situation in the
northern Ruhr region: in the Haltern
sands area, groundwater and seepage
water is used to produce drinking
water for around one million
people. Here, RAG must prevent contamination
of the groundwater body
through rising mine water by constantly
pumping it out.
Author: Ottmar Holz
The underlying information
was kindly provided by:
- "Fachpresseinformation Gateshead"
- GEA Group Aktiengesellschaft
- RAG Aktiengesellschaft
- The Coal Authority
GEA large heat pumps
GEA supplies heat pump solutions for a
wide range of industries, including the
food, dairy, beverage and district heating
industries. GEA's energy-efficient systems
are based on natural refrigerants.
Compared to synthetic refrigerants, they
offer double-digit percentage points better
performance. This is also reflected in
significantly lower energy bills - one of
the biggest cost drivers for industrial heat
pumps.
In addition to decades of experience
in refrigeration technology and with the
refrigerant ammonia GEA has been intensively
involved with heat pump applications
for around 15 years. The GEA
Heating and Cooling Technology Division
offers compression heat pumps with the
completely natural, climate-neutral and
highly efficient refrigerant ammonia up to
a target temperature of 95 °C target temperature.
According to the company, it
has already delivered more than 160 systems
worldwide (as of September 2022).
The average installed heating capacity per
system is around 1.5 MW. By June 2023,
the number of systems sold had already
increased to 185 units. GEA’s heat pump
portfolio comprises industrial-scale solutions
in the output range from a few hundred
kilowatts to around ten megawatts
per unit. It is therefore one of the most
efficient on the market and is constantly
being developed further.
GEA is currently installing four large
screw compressor heat pumps, including
a new LXHP70 bar high-efficiency screw
compressor, for the customer AS Utilitas
Tallinn in the Estonian capital Tallinn. The
plant will have a heating capacity of 24
MW, and Utilitas will use it to supply several
hundred households with sustainably
produced district heating.
GEA is one of the world's largest system
suppliers for the food, beverage and
pharmaceutical industries. Founded in
1881, the internationally active technology
group specialises in machinery and
systems as well as sophisticated process
technology, components and comprehensive
services.
GEA Group Aktiengesellschaft
Peter-Müller-Str. 12
40468 Düsseldorf, Germany
Telefon +49 (0)211-9136-0
www.gea.com
GREEN EFFICIENT TECHNOLOGIES 2023
29

Energy efficiency
Production technology
Companies that reduce their operating pressure from 6 to 4 bar can dramatically improve the profitability and sustainability of their operations.
Source: GettyImages/YouroPechkin
Reducing air pressure
in compressed air systems
GEA 4-bar valve actuators pave the way to 16 % energy savings
For food and beverage manufacturers
following a rigorous sustainability
roadmap, reducing energy
consumption and the carbon footprint
have become key priorities.
Compressed air accounts for a significant
portion of the electricity
used in processing plants. Changing
from the still prevalent 6-bar standard
to the more efficient 4-bar pressure
could save around 16% of this
electricity demand. GEA is the first
to support this agenda with a complete
range of 4-bar actuators for
all types of process valves, enabling
operators to make this cost-
efficient, climate-friendly switch.
Air itself may be free, but compressed
air is more expensive than many food
and beverage plant operators realize.
Energy costs are now an increasingly
dominant cost factor today, and
compressed air is regularly cited as
one of the most expensive and least
efficient forms of energy. According
to customers of the valve supplier
GEA, compressed air supply accounts
for approximately 10% to 15% of the
total electricity bill in typical food
processing plants, and this can add
up to several 100,000 EUR per year
in energy costs for compressed air
alone in a plant.
Reduce system pressure:
follow the 1-8 rule
Technical and environmental organizations,
such as the Fraunhofer
Fig. 1: GEA has launched the “Go 4 bar with GEA valve actuators” initiative: It draws attention
to the often unnecessarily high operating pressure in beverage production. Rule of thumb:
every bar saved results in approximately 8% less energy consumption in the compressor station.
Source: GEA
Institute for Systems and Innovation
Research and the German Fe deral
Environmental Agency, have studied
the problem of inefficient compressed
air systems and have identified significant
energy savings that can be
achieved by upgrading systems. Recommended
improvements range
from the installation of more energy-efficient
compressors to the use of
heat exchangers for energy recovery
and various programs to minimize
leakage. One particularly promising
step is to reduce the system pressure
for the compressed air applications
throughout the plant, which is
a relatively simple and efficient strategy
for both existing and new installations.
According to a study conducted
for the German Federal Environment
Agency, a 1 bar reduction in system
pressure can save approximately 8%
of the electricity required to operate
the compressor stations. This means
that if the system pressure is reduced
from 6 bar to 4 bar, there is a potential
saving of 16% in compressor
electricity.
Lower pressure also means less
friction in the air ducts and less leakage,
contributing to the 16% saving
from a 2-bar reduction. Leakage
losses typically account for about
10% of the total compressed air volume
in medium-size operations, and
a 1 bar reduction in system pressure
eliminates about 1/8 of these losses,
even without improving existing air
30 GREEN EFFICIENT TECHNOLOGIES 2023

Energy efficiency
Production technology
leaks. Lower air pressure and less
leakage also reduce the amount of
laborious hygienic cleaning, conditioning
and disposal of compressed
air required in most food and beverage
operations.
Facts speak: Example of a beverage
plant with 2 bar less
What are the cost implications of a
16% energy saving in compressor
operation? A practical example: For a
beverage plant in Germany that consumes
864,000 kWh of compressed
air per year, reducing the operating
pressure by 2 bar would result in
potential savings of 42,000 euros.
Pneumatic process valves –
how much pressure do they need?
Reducing system air pressure in
food processing plants has been
difficult until recently because the
stan dard pressure used to operate
pneumatic process valves has been
set at 6 bar or higher to ensure safe
products and processes. As a result,
most plants today have their system
pressure set at this 6 bar minimum,
and most valves installed have been
designed and implemented with
6 bar actuators.
However, advances in modern
valve technology have changed the
perspective on safe valve operation:
Today, valve actuators operating at
a reduced pressure of 4 bar can provide
the same level of reliability and
performance. This allows companies
to achieve optimum efficiency and
energy savings without compromising
the effectiveness of their automated
processes.
Enabling more plant operators
to make the switch
The prerequisite for setting up an
energy-efficient 4-bar compressed air
system is that all connected equipment
can use suitable 4-bar actuators.
GEA is the first valve supplier to
offer this option for the modular GEA
VARIVENT ® valve system with single
and double-seat valves to cover all
shut-off, switching and special functions
in hygienic processes as well as
for all butterfly valves in its own portfolio.
Depending on the situation, the
4-bar valve actuators can be retrofitted
to existing valves or integrated
into newly planned valves and valve
manifolds. If special compressed air
applications in the process require a
higher operating pressure of 5 bar,
these operating pressures between 6
bar and 4 bar can still be realized with
GEA’s actuator options.
For food and beverage manufacturers,
it is easy to switch to a lower
operating pressure with the right
valve configurations. And since the
Sample calculation: Beverage processing plant (Germany)
Total energy consumption p. a.:
Fig. 2: A change is worthwhile: modern 4-bar valve actuators are now just as reliable and
powerful as the standard 6-bar configurations.
7,200,000 kWh
12% electricity consumption for compressed air generation: 864,000 kWh
Electricity price (industrial tariff Q3/2023):
Proportionate energy costs p. a.
0.30 EUR/kWh
for compressed air generation (approx.): EUR 259,200
Reduction of system pressure from 6 bar to 4 bar
16% compressor energy saved by lowering by 2 bar (approx.) 140,000 kWh
Costs savings in energy p. a. (approx.): EUR 42,000
other compressed air systems, such
as those for conveying or aerating
ingredients, for filling and emptying
tanks, or for compressed air jet cleaning,
usually require pressures even
lower than 4 bar, there is an interesting
side effect: After the switching to
4 bar, these systems can be supplied
from the same compressor station as
the valve control, just as before.
By adopting this new approach
to saving energy by reducing system
pressure to 4 bar, companies can significantly
improve the sustainability
and cost-efficiency of their operations
over the long term.
References
I DEUTSCHE ENERGIE-AGENTUR,
FRAUNHOFER ISI, VDMA, Druckluft
effizient, Compressed Air Facts,
Karlsruhe/Germany, 2003 (PDF),
p. 4. A key reason for the low energy
efficiency of compressed air systems
is that most of the invested energy
is lost as waste heat during compression.
II See UMWELTBUNDESAMT,
Potenzialstudie Energie-/Kosteneinsparung
in der Fluidtechnik,
Abschlussbericht, Dessau-Roßlau/
Germany, 2021 (PDF), and
DEUTSCHE ENERGIE-AGENTUR
(2003).
III UMWELTBUNDESAMT (2021),
p. 64–65.
IV H.-J. MANGER, H. EVERS,
Compressed Air in the Brewery,
Berlin/Germany, 2008, p. 13.
GREEN EFFICIENT TECHNOLOGIES 2023
31

Hydrogen economy
Transport logistics
Dimethyl ether: new transport medium
for efficient hydrogen transport
Graphics: Research Centre Jülich GmbH
A possible solution to the transport
problem of the future hydrogen
economy can be found in many deodorant
or spray paint cans. Dimethyl
ether (DME) has long been used
here as a propellant gas. According
to new research, DME also has great
potential for transporting hydrogen
over very long distances.
Scientists from Forschungszentrum
Jülich, Friedrich-Alexander-Universität
(FAU) Erlangen-Nürnberg and the
Fraunhofer Institute for Solar Energy
Systems ISE have published an article
on dimethyl ether as a hydrogen storage
medium in the renowned journal
Energy & Environmental Science. In
the article, they describe the closed
DME/CO 2 cycle as a “previously underestimated
hydrogen storage system”
and highlight the potential of DME
for transporting hydrogen over very
long distances. According to them,
the technology is capable of exerting
a “significant influence on the future
global hydrogen economy”.
Known properties, new application
DME liquefies at low pressure. It is
highly flammable and forms carbon
dioxide (CO 2 ) and hydrogen (H 2 )
when it reacts with the help of water
vapour during a process known as
steam reforming. Liquefaction at
low pressure is relevant for use in
deodorant sprays. Under pressure
in the can, DME is liquid; when it is
released, it changes to a gaseous
state and is therefore suitable as a
carrier for the fragrance and active
ingredients of the deodorant. DME is
therefore one of the propellants that
have replaced CFCs, which are harmful
to the ozone layer.
“The properties of DME are all
known,” says author Dr Michael
Alders from the Institute for Sustainable
Hydrogen Economy (INW) at
Forschungszentrum Jülich. In addition
to the INW, the Helmholtz Institute
Erlangen-Nuremberg for Renewable
Energies (HI-ERN) was also involved
in the work on behalf of the research
centre.
Utilising the advantages of DME
Significantly more usable hydrogen
is released per mass of DME transported
than in the case of ammonia
or methanol. In addition, unlike
ammonia and methanol, DME is nontoxic
and therefore easier to handle.
“You can compare the handling of
32 GREEN EFFICIENT TECHNOLOGIES 2023

Hydrogen economy
Transport logistics
“The vapour reforming
of DME produces
hydrogen with a calorific
value of 8.7 kW/h”
DME with a gas such as butane, which
can be stored in a camping gas cylinder,”
explains Alders.
To store hydrogen in the form
of DME, CO 2 is hydrogenated in a
synthesis process at elevated temperatures
the hydrogen released. The energy
required for steam reforming and
ammonia splitting is not included.
“The main steps of DME-based
hydrogen storage are known. However,
they have not yet been com-
(T=200-300°C) and high bined into a hydrogen storage
pressures (p=30-100 bar). The synthesis
takes place in a two-stage process
through the hydrogenation of
CO 2 to methanol and the dehydration
of methanol to DME. The net reaction
equation is the reverse of the reaction
equation for hydrogen release in
technology,” says INW founding director
Prof Peter Wasserscheid, who is
one of the authors. “We at INW will
drive this forward in collaboration
with our partners. There is a great
deal of interest in the DME CO 2 hydrogen
storage system in industry."
steam reforming:
Returnable bottle principle
2 CO 2 + 6 H 2 C 2 H 6 O + 3 H 2 O
The authors conclude, among other
things, that DME is well suited to
transporting hydrogen over long sea
This means that 3 molecules of water
are formed per molecule of DME in
the synthesis, which can be fed back
into water electrolysis in the often
dry regions with high availability of
renewable energy (e.g. Australia).
routes. For example, from South
America or Australia - where there is
great potential for the production of
green hydrogen - to Europe. According
to author Sebastian Thill (INW),
it is conceivable that the hydrogen
The tempera ture required could then be released at the North
for hydrogen release in DME Sea ports by means of steam reforming.
(250°C-400°C) is compar able
The second decomposition pro-
to metha nol (250°C-300°C) and duct after the reaction, CO 2 , can
lower than
then be transported
back to
the hydrogen
production sites
on the same
ship, similar to
the principle of
the recyclable
deposit bottle,
and reloaded
with hydrogen
for ammonia
(400°C-600°C).
The volumetric
energy density
of six kilowatt
hours per litre
is higher than
that of methanol
(4.9 kWh/L)
and ammonia
(4.0 kWh/L). In terms of weight,
DME also contains the most energy
per kilogramme, namely 8.7 kilowatt
hours, compared to methanol
there. “We are talking about an emission-free
cycle in which the CO 2 used
is often utilised to transport hydrogen
and is not released into the
(6.2 kWh/ kg) and ammonia atmosphere,” says Thill.
(5.9 kWh/ kg). The energy densities
given refer to the calorific value of
When asked, Forschungszentrum
Jülich specified the higher efficiency
of the transport process. It is around
54.5 per cent for the entire DME/CO 2
cycle, including CO 2 back transport.
This figure reflects the ratio of the
energy content of the hydrogen supplied
to the energy consumed along
the process chain. The following
energy requirements are considered
here: Water desalination, electrolysis,
synthesis of the hydrogen carrier
(DME, methanol or ammonia), transport,
hydrogen release, direct air capture
and liquefaction of the CO 2 . The
efficiency for corresponding transport
processes based on methanol or
ammonia is around 46.1 per cent and
around 49.8 per cent respectively.
The return transport of the CO 2
is to take place in the same ship as
the transport of the DME. The CO 2 is
present as a liquefied gas at approx.
-50°C and a pressure of approx.
7 bar. The energy required to separate
the CO 2 after vapour reforming
has not yet been considered in
our previous calculations, but will
be included in the further course of
the techno-economic analysis. The
energy required for CO 2 liquefaction
amounts to approx. 1.68 MWh per
tonne of hydrogen released.
Contact:
Research Centre Jülich GmbH
Institute for Sustainable Hydrogen
Economy (INW)
Infrastructure and
Scientific Coordination (INW-I)
www.fz-juelich.de
www.hch2.de
Your media contact
D-A-CH
Thomas Mlynarik
Tel.: +49 (0) 911 2018 165
Mobile: +49 (0) 151 5481 8181
mlynarik@harnisch.com
INTERNATIONAL
GREEN EFFICIENT TECHNOLOGIES
Benno Keller
Tel.: +49 (0) 911 2018 200
keller@harnisch.com
GREEN EFFICIENT TECHNOLOGIES 2023
33

Hydrogen economy
Transport logistics
The potential of plastic pipes
in battery cell production
Lighter, more durable, more resistant
- Do these properties of plastic
piping systems also apply to their
use in battery cell production? The
Fraunhofer FFB, in cooperation with
GF Piping Systems, has published a
white paper entitled “Plastic piping
in battery cell production. A potential
analysis for production systems
and buildings”. It identifies and analyzes
potential applications for plastic
piping in battery cell production.
The whitepaper is the result of a
previously conducted study.
Battery cell production is a growing
industry, as it is considered a key
technology for the energy and
mobility transition in Europe. Until
now, production has primarily taken
place in China, but the market for
e-mobility is now booming in Europe,
allowing European companies to gain
a foothold in the battery industry. The
multi -step manufacturing process
offers many companies new points of
contact and therefore opportunities
to expand their product portfolio. As
Fig. 1: The various potentials of using plastic tubes in battery cell production: Weight, chemical
resistance, maintenance intervals, ease of installation, recycling and energy efficiency.
Source: Fraunhofer FFB
the scaling of battery cell factories is
a major factor in meeting the steadily
growing demand, optimization opportunities
are also being sought outside
of production that will lead to more
efficient and sustainable manufacturing.
One such could lie in using alternative
materials for piping systems:
The White paper questions the materials
of piping used within the building
and equipment and identifies key
application areas for flow solutions
made of plastics. The combination
of expertise in thermoplastics on the
part of the project partner GF Piping
Systems with expertise in battery cell
production on the part of Fraunhofer
FFB has led to new findings.
What are the necessary specifications
for pipes in a battery factory?
Since the conditions in cell production
are very specific at some locations,
Fraunhofer FFB has pooled its
interdisciplinary expertise to conduct
the potential analysis. To do so, we
developed a technology management
Fig. 2: The different process steps of battery cell production and the possible applications of plastic tubes.
Source: Fraunhofer FFB
34 GREEN EFFICIENT TECHNOLOGIES 2023

Sustainable
conveying of
complex media
Fig. 3: Overview graphic of the different temperature requirements in clean and dry rooms in battery
cell production.
Source: Fraunhofer FFB
methodology tailored to the requirements
of the areas under investigation.
Four criteria form the basis on which
potentials for plastic piping compared to
stainless steel pipes are to be researched
- environment, compatibi lity, market, and
value. The environment in this context
refers to the process parameters that
could have an impact on plastic pipes,
such as pressure and temperature. Under
the compati bility criterion, the compatibility
of chemical substances with the
pipe material is examined. In addition,
the value that plastic pipes could add to
the process in question is determined.
Furthermore, in addition to the need
for piping in a Gigafactory, its area of
use, the environmental conditions, and
the properties of the transported substances
play an essential role. An examination
of the individual process steps
reveals the following main areas of application:
Potential areas of application for
piping technology are not only in the field
of technical building equipment (TGA)
but also especially in clean room and dry
room technology as well as in some process
steps from electrode manufacturing
to forming.
Plastic piping systems are particularly
interesting for the mixing process
since the environment does not place
high demands on the materials here.
Thanks to their chemical resistance and
smooth surfaces, they are well suited
for the transport of granular and liquid
raw materials as well as mixed slurry,
which can cause corrosion in metal. But
systems made of plastic can also help
reduce costs and the carbon footprint
in clean and dry rooms. The entire process
chain has different but specific temperature
requirements depending on the
process step, which is why the amount
of piping for various heating and cooling
circuits is enormous. It is precisely in
these areas that plastic piping systems
can bring about greater environmental
friendliness.
Further potentials of plastic components
lie in weight, service life, recyc ling
possibilities, installation time, and energy
efficiency. The extent to which these
also come into play in individual areas
of battery cell production is shown in the
white paper.
You can read the whitepaper here:
https://www.ffb.fraunhofer.de/content/
dam/ipt/forschungsfertigung-batteriezelle/
Dokumente/whitepaper/GFDO_BR_00099_
EN_FFB_Whitepaper_Digital.pdf
Fraunhofer Research Institution for
Battery Cell Production FFB
Bergiusstrasse 8
48165 Münster
Germany
www.ffb.fraunhofer.de
Georg Fischer GmbH
Daimlerstr. 6
73095 Albershausen
Germany
www.gfps.com/batteryproduction
GREEN EFFICIENT TECHNOLOGIES 2023
This is how you convey
complex media effectively
Choosing the right pump optimizes the
processes and reduces energy costs.
NETZSCH offers:
Individual consultation
More than 70 years of experience
5 different technologies
Each technology offers specific benefits for
you. Contact us, we will find the optimal
solution for your application.
Green beyond the
corporate colors
We produce durable
capital goods and
support a sustainable
approach through
many years of supplying
spare parts and competent
service.
Contact our
experts now:
NETZSCH Pumpen & Systeme GmbH
www.pumps-systems.netzsch.com

Hydrogen economy
Safety concepts
More than just a standard
Highly specific safety concepts
for hydrogen infrastructures
Successful venting of a hydrogen explosion at REMBE Research+Technology Center GmbH.
In the context of the desired decarbonisation,
hydrogen is becoming
increasingly important as an energy
carrier (thermal utilisation) and
as a starting material for chemical
production lines (molecular utilisation).
Plant operators and manufacturers
of specific subcomponents
often plan to use methane-hydrogen
mixtures initially, and then to
continuously increase their hydrogen
content. The long-term goal is
to completely substitute methane
with hydrogen. However, it is often
disregarded that the safety concepts
and technologies suitable for
the original methane operation are
only functional to a limited extent
or not at all for protecting plants,
single components and infrastructure
during operation with high
hydrogen concentrations.
Particularly in the area of explosion
protection, as well as pressure venting
at medium to very high overpressures,
the existing concepts must be
carefully reviewed using the available
models, and possibly re-evaluated.
A comparison of the explosion
characteristics of stoichiometric
methane-air and hydrogen-air mixtures
quickly makes this necessity
clear.
Unit Methane Hydrogen
Lower explosion limit Vol-% 4,4 4,0
Upper explosion limit Vol-% 17,0 77,0
Limiting oxygen concentration Vol-% 9,9 4,3
Min. ignition energy mJ 0,23 0,017
Ignition temperature °C (°F) 595 (1103.0) 560 (1040.0)
Flame temperature °C (°F) 1970 (3578.0) 2130 (3866.0)
K G bar m s -1 68,4 550
Laminar burning velocity S u cm s -1 43 346
Max. explosion pressure bar 8,2 8,2
Fig. 1: Comparison of explosion characteristics under atmospheric conditions (20°C; 1.01 bar)
Sources: BAM final report on research project 2539 and own investigations.
36 GREEN EFFICIENT TECHNOLOGIES 2023

Hydrogen economy
Safety concepts
If the maximum explosion pressure at
atmospheric conditions is about 8 bar
in each case, significant increases can
be observed both in the KG value (rate
of pressure rise) and in the laminar
flame propagation speed. This may
mean that safety devices tested with
methane explosions show too high
inertia for the rapid pressure increase.
Valve-type protective systems can be
severely damaged when they respond
that they do not return cleanly to their
original state and their functionality
is impaired or they are operated
unsafely. Special care must be taken
when designing and assessing the
geometric dimensions and sizing. For
example, certain length-to-diameter
ratios of vessels and pipes, especially
for hydrogen as a Class IIC gas, favour
the tendency towards detonative transition.
If explosions propagate from
one vessel to another via a pipe, there
is also the risk that the ignitable mixture
is pre-compressed in the second
vessel, which results in significantly
higher explosion pressures compared
to explosions under atmospheric conditions.
A hydrogen-air mixture is also
more susceptible to ignition than a
methane-air mixture due to the lower
ignition energies and ignition temperature.
In addition to the expected more
severe course of events, the probability
of occurrence is also higher.
Hydrogen explosions under
prepressure
In addition to the aforementioned
se condary prepressurisation in the
event of an incident, there are applications
in which ignitable mixtures
are deliberately precompressed and
can ignite uncontrollably under certain
circumstances. For several reasons,
these scenarios pose a special challenge
with regard to the design of the
corresponding equipment and to the
constructive protection concepts.
Firstly, the existing normative
regu lations do not provide any models
for the design of safety relief devices
for gas explosions under prepressure.
Due to the prepressure at high dynamics,
the problem at hand is neither
covered by DIN EN 14994 (Gas explosion
venting protective systems) nor
by DIN EN ISO 4126 (Safety devices for
protection against excessive pressure).
Thus, there are no assured design
stan dards, which means that the
problem is in the “grey area of safety
technology”. Secondly, the explosion
dynamics are significantly influenced
by barely assessable turbulence-generating
effects, which primarily result
from the geometry at hand. Thus, it
is difficult to predict what explosion
pressures, flame propagation speeds
and rates of pressure rise are to be
expected. Whether a detonative transition
occurs and whether an explosion
venting device is suitable to protect the
present scenario therefore requires
separate investigations.
One possible way to validate a
safety concept for the “hydrogen
explosion under prepressure” problem
dealt with here – in addition to
very complex numerical simulations
– is experimental verification. For this
purpose, the protection scenario is
simulated as realistically as possible
with flameproof components and the
explosion pressure resistant concept
is tested with regard to its functionality
via repeated explosion tests. Starting
from a stoichiometric methane-air
reference test, either the proportion
of hydrogen in the methane-hydrogen-air
mixture, the prepressure or
the combustion air ratio is increased
when testing a pure hydrogen-air mixture,
depending on the problem. By
registering the pressure curves within
the simulated structure, the maximum
explosion pressure can be inferred
and the tendency towards detonative
transition can be estimated. The aim
of the verification is always the identification
of safe operating parameters
as well as to check product suitability,
as no standard product certification
is available due to the lack of a normative
basis. When selecting a suitable
product/explosion venting device,
it is important to ensure that it is not
only suitable for explosion venting,
but also guarantees a long and reliable
service life under the prevailing
conditions during normal operations.
If the explosion venting device was
an explosion vent or rupture disc, the
burst pressure, operating ratio, working
temperature as well as the occurrence
of vibrations and cyclic loads
and, of course, the corresponding
Fig. 2: REMBE produces high-quality explosion
vents and rupture discs that are not
only aesthetically appealing, but also suitable
for safely venting hydrogen explosions
under prepressure.
material must be taken into account
when making the selection.
REMBE GmbH Safety+Control
has been a leader in the technological
fields of Process Safety and Explosion
Safety for almost 50 years. As
such, the careful selection of suitable
safety systems and (explosion) relief
devices are key aspects of the company’s
service portfolio. REMBE has thus
built up a profound understanding of
how to analyse customers’ processes
and plants and identify suitable protection
technologies. In collaboration
with REMBE Research+Technology
Center GmbH, an independent testing
laboratory accredited to EN ISO/
IEC 17025:2018, REMBE can also validate
even highly complex protection
concepts on an experimental basis.
Especially in scenarios where new
technologies need to be tested, no
assured design standards are available
or high-precision protection concepts
are required, it is precisely this
multidisciplinary approach that enables
REMBE to develop high-quality
solution concepts. In collaboration
with the customer, the company combines
experimental verification with its
extensive expertise in explosion safety
and explosion venting solutions to create
highly specific protection concepts
tailored to the customer's processes.
REMBE ® GmbH Safety+Control
Gallbergweg 21
59929 Brilon, Germany
Tel: +49 2961 7405-0
www.rembe.de
GREEN EFFICIENT TECHNOLOGIES 2023
37

Companies - Innovations - Products
The Smart H 2
Energy Platform:
A revolution in the energy supply
of buildings.
Cosber turns the energy supply of buildings upside down with its
CO 2 -free and self-sufficient hydrogen-based energy system. The
SMART H 2 Energy Platform is a holistic system that radically transforms
the energy supply of buildings. It provides secure and decentralized
CO 2 -free energy to residential and commercial properties 24/7, 365
days a year. This is achieved through the smart combination of renewable
energies as an energy source and green hydrogen as an energy
storage solution. Excess energy generated by solar panels on sunny
summer days is stored as green hydrogen and utilized for power and
heating during the dark winter months.
This entire system is based on the latest technologies for hydrogen
production, storage, and electricity conversion. It is complemented
by solutions for the most efficient and CO 2 -free generation and utilization
of electricity, including photovoltaic systems, heat pumps,
and lithium- ion battery storage. The centerpiece of this system is the
An additional strength of the Smart H 2 Energy Platform is the ability
to leverage synergies between its individual components to enhance
the overall system efficiency. The integration of ground or water heat
pumps, in particular, proves highly advantageous. The hot water generated
by the water-cooled fuel cell during the conversion of hydrogen
into electricity can be used to boost the efficiency of the heat pump. As
the majority of hydrogen-to-electricity conversion occurs in the colder
months, the HPC and a ground or water heat pump complement each
other perfectly. The Smart H 2 Energy Platform proves to be the ideal
choice for property owners seeking not only increased efficiency but
also a more environmentally friendly and autonomous energy supply
of their buildings. Its modular design and holistic approach make it
the perfect solution for a wide range of buildings, from single-family
homes to commercial properties of various sizes. This innovative platform
empowers building owners to fundamentally reconsider their
energy supply, establishing a sustainable, CO 2 -free, and independent
life style.
Thanks to its modular structure, Cosber can tailor solutions precisely
to the requirements of each building. In summary, the Smart H 2
Energy Platform empowers building owners to create a sustainable
energy future for their properties, regardless of their type or size.
COSBER Technology Co., Ltd. is a renowned manufacturer of
vehicle testing technology and comprehensive hydrogen solutions.
Since its establishment in 1999, the company has evolved into an innovative
high-tech enterprise with a global presence. With over two decades
of experience in developing and manufacturing high-quality and
precise measurement technology, Cosber delivers cutting-edge products
to its customers. International operations span across more than
50 countries, with branches and production facilities in China and Germany.
The 300-member team at COSBER works daily to provide customers
with efficient and innovative solutions in the fields of vehicle
testing technology and hydrogen.
Cosber Technology Ltd.
8 th floor, Building A, No28 Dongyang
3 rd Road, Danzao Town, Nanhai District
Foshan, Guangdong, China
www.cosber.com
Cosber Hydrogen Power Cube (HPC). The HPC converts excess electricity
from a photovoltaic system or another renewable energy source
through electrolysis into hydrogen, compresses and stores it, and converts
it back into electricity and heat as needed through a fuel cells.
The modu lar structure of the HPC is reflected in its division into three
largely autonomous units: the ESS unit, the hydrogen production and
conversion unit, and the hydrogen storage unit. The strength of the
HPC lies in the optimized and coordinated combination of these three
units. An integrated control system facilitates communication between
all units and optimally synchronizes their operation.
The ESS unit of the HPC consists of a hybrid inverter with two MPP
trackers and a lithium battery storage with a capacity of up to 30 kWh,
easily expandable or reducible. It caters to the daily short-term power
needs of the users building for example during night time. The hydrogen
production and conversion unit include an AEM electrolyzer with
an integrated water treatment system and a water-cooled PEM fuel
cell with a power output of 11 kW and bipolar plates. The hydrogen
storage unit incorporates a compressor for hydrogen compression to
350 bar, a buffer unit, and multiple hydrogen tanks, each with a capacity
of 110 liters.
First Graebener stack press
realized for world’s leading
electrolyzer manufacturer
Production technology for alkaline electrolyzers
comes from Germany
The hydrogen expert Graebener expands its product portfolio and supplies
one of the most renowned electrolysis companies with its latest
innovation, the stack press. Graebener Maschinentechnik, a custom
machine building company that is more than 100 years old, is a specialist
in the development of customized systems. With its Graebener
Bipolar Plate Technologies division, it entered the hydrogen market as
early as 2003 and has since made a name for itself worldwide.
Graebener Bipolar Plate Technologies focuses on the development
of technologies and machines for the production of fuel cell and
38

Companies - Innovations - Products
electrolysis components, such as the metallic bipolar plate. The latest
development is a press that is used in the manufacturing process of
alkaline electrolyzers.
Electrolyzers make a significant contribution to the energy transition
because they can be used to convert electricity, preferably from
renewable sources, into hydrogen. This, in turn, can be used in a variety
of ways as a green energy source, for example to decarbonize the
industry. The heart of every electrolyzer is its stack, which consists of
hundreds of stacked single or bipolar plates. The chemical conversion
of electrical energy into hydrogen then takes place within these stacks.
As one of only a few companies worldwide, Graebener offers not
only individual machines for forming, cutting, welding and straightening
metallic single and bipolar plates, but also complete lines for
series production: from coils to welded and leak-tested bipolar plates.
Graebener has long been known for this. The recently developed system,
however, is used in a later production step, namely in the manufacturing
of the actual stack.
Technology to support stack testing
The Graebener stack press supports the technical testing of electrolysis
stacks at the end of their production process: The pre-assembled
stack, which consists of a large number of plates, is first moved into
the machine and then compressed to a defined height until a certain
pressure is reached within the stack. This pressure must then be maintained
unchanged for several hours. At this time, the stack is subjected
to all the necessary technical tests carried out by the customer and
with the help of further procedures. These are necessary to confirm its
full operability. As soon as the tests are completed, the stack is finally
assembled with tie rods or tension straps and the finished stack is
removed.
Precision with maximum safety
The stack press for electrolyzers has a force of 800 tons and can handle
stacks with a maximum height of approx. 3.0 m, a maximum diameter
of 1.60 m and a weight of up to 12 tons per stack.
In order to be able to guarantee assembly work during operation
with maximum safety, a hydraulic drive was deliberately avoided.
Instead, the stack is compressed inside the press by means of six
servomotor-driven spindle units. These are operated synchronously
and thus enable particularly homogeneous compression of the stack.
The maximum pressing force per spindle unit is 150 tons.
The biggest challenge was to compensate for production-related
stacking tolerances. Stacking tolerances are unavoidable, but when the
stack is compressed, they cause transverse forces which can damage
the stack. In order to eliminate these and to build up an even pressure
distribution within the stack, these transverse forces must be continuously
compensated for during compression of the stack. This is done
with short-stroke cylinders that are located under the six spindle lifting
elements and enable an even distribution of pressure.
As a custom machine builder, Graebener always develops its
machines to meet specific applications and customer requirements.
Graebener had already realized a similar press in the past, but at that
time for fuel cell stacks. However, since plates for alkaline electrolyzers
- and thus also their stacks - are usually many times larger, the design
of the current system was much more complex.
Gräbener Maschinentechnik GmbH & Co. KG
Am Heller 1
57250 Netphen, Germany
Tel +49 2737 989-0
info@graebener.com
www.graebener.com
Index of Advertisers
Aerzener Maschinenfabrik GmbH
Deutsche Messe AG
Cover page
2. Cover page
NETZSCH Pumpen & Systeme GmbH Page 35
Lutz Pumpen GmbH Page 40
SEW-EURODRIVE GmbH & Co. KG Page 5
URACA GmbH & Co. KG Page 40
GEA Tuchenhagen GmbH Page 15
Hammelmann GmbH Page 25
IVS - Industrial Valve Summit
3. Cover page
39

Brand name register
Aerzener Maschinenfabrik GmbH
Reherweg 28
31855 Aerzen/Germany
Phone: +49 (0)5154 81-0
Fax: +49 (0)5154 81-9191
E-mail: info@aerzen.com
Website: www.aerzen.com
Positive displacement blowers
Rotary piston compressors
Screw compressors
Turbo blowers
Rotary piston gas meters
For exhibition-participation
please visit our homepage
www.aerzen.com
GEA Tuchenhagen GmbH
Am Industriepark 2-10
21514 Büchen/Germany
Phone: +49 (0)4155 49-0
Fax: +49 (0)4155 49-2423
E-mail: flowcomponents@gea.com
Website: www.gea.com
Hygienic valves
Hygienic pumps
Aseptic valves
Cleaning technology
Further information are available
on our website:
www.gea.com
We are looking forward to your visit!
Hammelmann GmbH
Carl-Zeiss-Str. 6-8
59302 Oelde/Germany
Phone: +49 (0)2522 76-0
Fax: +49 (0)2522 76-140
E-mail: mail@hammelmann.de
Website: www.hammelmann.de
High-pressure plunger pumps
Process pumps
Sewer cleaning pumps
Mining pumps (deep mining industry)
Hot water appliances
Operating pressure up to 4000 bar
Flow rate up to 3000 l/min
Applications systems for cleaning, removing,
cutting, coating removal, decorning, deburring
with high pressure water
Worldwide participations in trade
fairs,for current trade fairs, please visit
our homepage:
www.hammelmann.com
We are looking forward to your visit!
Lutz Pumpen GmbH
Erlenstr. 5-7
97877 Wertheim/Germany
Phone: +49 (0)9342 879-0
Email: info@lutz-pumpen.de
Website: www.lutz-pumpen.de
Lutz Pumpen GmbH is a leading manufacturer of
industrial pumps with a focus on work safety and the
highest demands.
The product range includes drum pumps, container
pumps, air-operated diaphragm pumps, flow meters,
centrifugal pumps as well as system solutions.
Current trade fair dates can be found
on our website:
www.lutz-pumpen.de
NETZSCH Pumpen & Systeme GmbH
Geretsrieder Str. 1
84478 Waldkraiburg/Germany
Phone: +49 (0)8638 63-0
E-mail: info.nps@netzsch.com
Website:
www.pumps-systems.netzsch.com
As a specialist for conveying complex media,
NETZSCH develops customised and sophisticated
pump solutions on a global level. The product
spectrum ranges from the industry’s smallest
metering pumps to high-volume pumps for
applications in the oil & gas or mining industries.
NETZSCH offers NEMO ® progressing cavity pumps,
TORNADO ® rotary lobe pumps, NOTOS ® multi screw
pumps, PERIPRO ® peristaltic pumps, grinders, dosing
technology and barrel emptying units, accessories
and service.
For current trade fairs, please visit:
www.pumps-systems.netzsch.com/
en/events
SEW-EURODRIVE GmbH & Co KG
Ernst-Blickle-Str. 42
D-76646 Bruchsal
Tel.: +49 (0)7251 75-0
Fax: +49 (0)7251 75-1970
E-mail: sew@sew-eurodrive.de
Website: www.sew-eurodrive.de
SEW-EURODRIVE is one of the global market leaders
in drive technology and automation.
It has 17 production plants and 88 Drive Technology
Centers in 54 countries. The company was founded
in 1931. The Headquarter is in Bruchsal, Germany.
The turnover was 4.2 billion EUR in the fiscal
year 2022. More than 21,000 employees work for
SEW-EURODRIVE.
For current trade fairs please visit
our website
https://www.sew-eurodrive.de/
trade-shows
URACA GmbH & Co. KG
Sirchinger Str. 15
72574 Bad Urach/Germany
Phone: +49 (0)7125 133-0
Fax: +49 (0)7125 133-202
E-mail: info@uraca.de
Website: www.uraca.de
URACA designs and manufactures high-pressure
plunger pumps and pump units as well as complex
cleaning systems for satisfied customers all over
the world.
• High pressure plunger pumps
up to 3,500 kW/3,000 bar
• Sewer cleaning pumps
• High pressure pump units for industry and
cleaning, for hot and cold media
• Tools and accessories
• High pressure water jetting systems
• Hydrostatic pressure test pumps
For current trade fairs
please visit our website
www.uraca.de
40

Dr. Harnisch Verlags GmbH
Eschenstraße 25
90441 Nuremberg, Germany
Phone + 49 (0) 911 2018-0
Fax + 49 (0) 911 2018-100
E-Mail GET@harnisch.com
Internet www.harnisch.com
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