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Hansa coking plant –
the history of the
industrial monument

Index
Welcome to the Hansa coking plant.................................. 4
Hansa coking plant –
the history of the industrial monument
In the beginning was the colliery............................................................ 6
Merging for rationalisation.................................................................... 9
Working hand in hand – the integrated production process..................... 10
The birth of the central Hansa coking plant............................................ 13
Customised expansion –
production planning and conception .................................................... 14
Rearmament and expansion ................................................................ 17
The end – and a truly monumental new beginning .. 20
Good times .................................................................................... 22
Clever planning ................................................................................ 25
New paths ....................................................................................... 26
Roof gardens on the coking ovens ....................................................... 28
Rain collectors and cloud makers ........................................................ 30
An extra curricular place of learning .................................................... 32
The art lab ........................................................................................ 34
A well-preserved monument ................................................................ 37
From coal to coke –
a trip through the production process in a coking plant
What is a coking plant – a brief introduction ......................................... 40
The path of coal
Delivery ............................................................................................ 42
The coke oven battery ........................................................................ 43
The coke pusher engines and the quenching wagons ............................. 45
The quenching tower .......................................................................... 45
The path of gas
Drawing off the crude gas .................................................................. 47
Producing the by-products tar and phenol.............................................. 47
Ammonia, hydrogen sulphide and benzene .......................................... 48
Compressing and cooling ................................................................... 50
Chronicle ................................................................................... 52
Further reading ....................................................................... 55
Site plan ..................................................................................... 56
Imprint
2
HANSA COKING PLANT – THE HISTORY OF THE INDUSTRIAL MONUMENT
INDEX 3

The Hansa coking plant amongst the trees. Photo: 2008
Welcome
to the Hansa coking plant
The Hansa coking plant industrial monument has been winning over the
hearts of visitors since it opened in 1999. Every year thousands of people
take the opportunity to explore the “gigantic sculpture” along the Nature and
Technology Adventure Trail. At the end of the 1990s people thought that list -
ing a coking plant and preserving it for posterity was a somewhat audacious
proposition, but today this is almost taken for granted. That said, it was only
made possible after a long planning process, and the commitment of the
State of North-Rhine Westphalia, the RAG company and above all the current
owners of the coking plant, the Foundation for the Preservation of Industrial
Monuments and Historical Culture. Here, local people and politicians also
deserve a special mention for their steadfast commitment to ensuring the
preservation of the industrial monument. The advocates of preservation did
not always meet with approval and for a long time there were loud demands
to demolish the coking plant. Happily these times are long past. “Hansa” is
now an established part of the cultural landscape and interest in the coking
plant is continually rising, both from visitors and users alike.
The Foundation for the Preservation of Industrial Monuments and Historical
Culture is responsible for preserving the building substance of the industrial
monument, conducting research into the monument, making it accessible to the
general public and putting it to new uses. It places great value on presenting
the Hansa coking plant by means of tailor-made guided tours for the general
public, not forgetting particular target groups like children, young people and
families, and even specialists like conservationists, historians, landscape
planners, architects, photographers and engineers. Strolling through the industrial
monuments has proved its worth time and time again because only then
can individuals literally have a step-by-step appreciation of the dimensions
and production capacities of the coking plant over and above the bare statistics
in tons and cubic metres. Anyone who has ever walked through a bunker
with a capacity of 4,000 tons of coal, stood in front of one of the original
314 coke ovens, and seen a compressor in action, returns home not only with
a rich treasury of knowledge about the history and importance of the coking
plant, but also with some powerful images in their heads. After completing
a tour of the site visitors are always demanding more information in order
to deepen their knowledge and impressions, or simply to take home some
warm memories of their visit to the Hansa coking plant.
We are delighted to do something to satisfy this need in the form of the
present brochure, and wish you a pleasant read!
The staff of the Foundation for the Preservation of Industrial Monuments
and Historical Culture
Ursula Mehrfeld
Business head
dieindustriedenkmalstiftung
4 HANSA COKING PLANT – THE HISTORY OF THE INDUSTRIAL MONUMENT
WELCOME TO THE HANSA COKING PLANT
5

Hansa coking plant –
the history of the
industrial monument
In the beginning was the colliery
Both the name “Hansa” and the later “Hanseatic history” came about as a
result of mergers. Coal was discovered as early as 1810 during drilling work
on fountains in the then village of Huckarde. In 1856 the chief mining officer
Wilhelm von Hövel sold his prospecting licence to the Dortmund Mining and
Ironworks company, which then merged the mining field in Huckarde with
those in Wischlingen and Rahm under a new name: Hansa. The name referred
to the mediaeval Hanseatic League, an international economic and
trading alliance, and was intended to symbolise hopes for a business upturn
in the then rural region. Some time later work began on sinking a shaft for
the Hansa colliery. Coal was first brought to the surface here in 1869.
The Hansa colliery ca. 1890. At the time the 84 meter chimney stack on
the boiler house was the highest chimney stack in the Ruhr region.
A good quarter of a century later, in 1895, the plant experienced a crucial
modification. The industrial tycoon Friedrich Grillo now owned the majority
of shares in the company and decided to expand the works with the addition
of a small colliery coking plant, south of today’s Lindberghstrasse. This was
where the first “Hansa coke“ was produced. At first the plant contained more
than sixty coke ovens, and after it was expanded in 1905 production rose to
around 96,000 tons of coke per year. The coking plant site remained in
operation for a total of 30 years.
The Hansa colliery in 1898 with the so-called “Weyhe” shaft (the
Malakov tower on the left in the picture, taken out of operation as
early as 1859), shaft 1 and shaft 2 and the coal washing plant.
6
HANSA COKING PLANT – THE HISTORY OF THE INDUSTRIAL MONUMENT
IN THE BEGINNING WAS THE COLLIERY
7

Merging for rationalisation
After the First World War there was a major upheaval in the coal and steel
industries in the Ruhrgebiet. Following the model of large-scale industries in
the United States, German companies made plans to stimulate the economy
by mergers and rationalisation. The upshot was that, in 1926, the four major
coal and steel companies – the Rheinelbe-Union, the Thyssen Group, the
Phoenix Group and the Rhineland Steelworks – merged to become the United
Steelworks Company. The new concern comprised around one hundred
collieries, coking plants and steelworks, and now rose to become the second
largest steel concern in the world, thereby preparing the way for technical
improvements and, most importantly, an up-to-date integrated business
concern.
Coking plants were an important factor in the integrated system. Until then
most of the small coking plants on the colliery sites belonging to the United
Steelworks were out-of-date and unprofitable. For this reason seventeen new
major coking plants were built in the Ruhrgebiet between 1926 and 1929.
From now on they were responsible for providing more than half the total of
coke produced in the Ruhrgebiet.
The Hansa colliery in 1911 with the gatehouses containing the tag checker’s
office and the accident room. On the right, the warehouse building.
8 HANSA COKING PLANT – THE HISTORY OF THE INDUSTRIAL MONUMENT
MERGING FOR RATIONALISATION 9

Working hand in hand – the integrated production process
The most important technical precondition for running central coking plants
in an integrated production process was the presence of integrated coking
ovens. They were more efficient than earlier ovens because they could not
only be fired by rich gas – for example their own purified coking plant gas –
but also by blast furnace gas. This meant that large quantities of high-value
coking plant gas became available for use in casting and rolling mills. In
return the blast furnace gas produced in the steelworks could be sent back
to the coking plant to fire the ovens. The result was an integrated system of
gas supplies between the coking plants and their associated steelworks.
The overhead pipelines used to conduct the gas were to remain one of the
typical urban images in the Ruhrgebiet for years.
Alongside its uses in the steel industry, coking gas – when correctly prepared
and compressed – could also be fed into the long-distance gas grid. The Ruhrgas
Company was set up in 1926 and immediately took advantage of the
concentration of gas production in the central coking plants to systematically
raise production levels even further. Now the urban gasworks dotted all over
the region gradually became superfluous and were taken out of production
one by one. Coke oven gas became more and more important as a basic
chemical material because of the by-products it contained like crude tar,
benzene and ammonia.
The Dortmund Union steelworks. Photo: 1929
At first the Hansa coking plant
delivered coking plant gas to the
Dortmund Union steelworks, and
later to the Phoenix steelworks. In
return the coking plant received
furnace gas to fire the coking
ovens. Drawing: 2008
10
HANSA COKING PLANT – THE HISTORY OF THE INDUSTRIAL MONUMENT
WORKING HAND IN HAND – THE INTEGRATED PRODUCKTION PROCESS
11

The new coking plant was
planned according to the production
process. Potential later
extensions were also included
in the overall concept. Isometric
drawing: 1930
One for all. In 1927 the United
Steelworks began work on
constructing the central Hansa
coking plant (photo: Battery 2).
The plant replaced the coking
plants at the Hansa, Zollern,
Adolf von Hansemann and
Germania collieries.
Photo: 1927-28
At first two batteries, each
containing 65 coke ovens, were
constructed at Hansa. The narrow
chambers, only 41 centimetres in
width, were built by hand using
bricks specially made to conduct
heat. Photo: 1927-28
Battery 2. In the background
can be seen the presser engine
which pressed the finished coke
out of the oven. The photo was
taken before July 1929
The birth of the central Hansa coking plant
In 1927 the United Steelworks started work on the construction of the central
Hansa coking plant. By contrast with traditional colliery coking plants it was
planned to take coal from several collieries – not only from Hansa, but also
from the shafts at the Westhausen and Adolf von Hansemann collieries. The
new coking plant was to be sited on an area of land 450 metres north-west
of the Hansa colliery. There were two crucial reasons for this decision: it was
extremely close to the Cologne to Minden railway line, and there was already
a railway connection to the “Dortmunder Union” Steelworks, which also
belonged to the concern and could be supplied with the coke produced
almost next door. The decision to build a major coking plant in turn resulted
in the expansion of the Hansa colliery to a major colliery, because it could
supply above-average amounts of coking coal.
It goes without saying that the ovens at the new Hansa coking plant site
were highly up-to-date. Larger ovens and lower baking times combined with
a broad mechanisation of the ovens made it possible to raise production
levels enormously from four to sixteen tons a day. The plant opened in 1928,
and comprised 130 ovens arranged in batteries number 1 and 2. At the
start it was planned to produce 2,200 tons of coke a day – an equivalent
annual amount of 770,000 tons. The ovens were for the most part fired by
blast furnace gas from the Dortmunder Union steelworks. The plant dealing
with long distance gas was constructed between 1928 and 1931, thereby
completing the integrated gas system between the steelworks and the Ruhrgas
long distance grid. Extensions came to an end in 1934 when the large
gasometer went into action.
Hansa coking plant. Site map: 1930
12
HANSA COKING PLANT – THE HISTORY OF THE INDUSTRIAL MONUMENT
THE BIRTH OF THE CENTRAL HANSA COKING PLANT 13

Customised expansion – production planning and conception
Hellmuth von Stegmann und Stein, a construction director at the United Steelworks,
was given the job of drawing up the plans for enlarging the Hansa
coking plant. The most important feature in his conception was the arrangement
of the buildings and plants to fit in with the production process. In
addition his plans allowed for further expansions at a later date.
The technical plants and buildings were arranged in an “urban development”
ensemble. The basic grid was simple. There were two parallel main roads.
The plants for the coke production plants were situated on the so-called
“black” side. These included the sorting tower, the coal towel and bunkers,
the mixing and crushing plants, the coke oven batteries, the quenching towers,
the coke ramps and the screening plant. The “white” side contained a row
of chemical plants for extracting and preparing the valuable by-products
from the coking gas: the benzene factory, the ammonia factory, the salt store,
the compressor house and the workshops. The workers’ washroom and the
administrative buildings were also situated along this road.
At first the compressor house was fitted out with two compressors for
compressing the coking plant gas to be sent to the grid. Subsequently it was
enlarged step by step. From 1942 onwards 5 gas compressors manufactured
by the Demag company worked on a piece work basis. Photo: 1930
A huge number of pipelines connected the “black” and “white” sides. These
were, so to speak, the blood vessels and nerves of the coking plant. Alongside
the two parallel main roads and the criss-cross of conveyor bridges,
pipeline bridges and railway lines, there was a further important transportation
system for taking the coke to the outside world. Here we should also
mention the so-called “skylift”, a prominent feature of the Hansa coking plant
skyline between 1928 and 1945. This was an overhead cableway that took
the coal from the Westhausen and Adolf von Hansemann collieries directly
to the sorting tower in the Hansa coking plant.
Until 1945 coal from the Westhausen
and Adolf von Hansemann colliery
was delivered by overhead cable.
Later this was delivered by rail.
The Hansa colliery delivered its
coking coal via a specially constructed
conveyor belt known as
the “Hansa belt”. Photo: 1952
14
HANSA COKING PLANT – THE HISTORY OF THE INDUSTRIAL MONUMENT
CUSTOMISED EXPANSION – PRODUCTION PLANNING AND CONCEPTION
15

Rearmament and expansion
In the years up to 1938 the Hansa coking plant underwent considerable
expansion. As a result of the Nazi rearmament plans and the autarchy
policies the site north of the existing coke ovens was given two new batteries,
each containing eighty Koppers by-product coke ovens. At the same time
the plant was given a second coal tower and a second screening area. The
chemical plants were extended, and the compressor house was enlarged to
contain five additional engines. With an eye to production for the Second
World War, Hansa was now the largest coking plant in the Ruhrgebiet with
a capacity of 1,700,000 tons a year.
Construction work on Battery 3, 1938: Extensions to the plant were
completed in 1942, thereby making Hansa the largest coking plant
in the Ruhrgebiet. Photo: 1938.
Battery 4 in action in the 1950s
16
HANSA COKING PLANT – THE HISTORY OF THE INDUSTRIAL MONUMENT
REARMAMENT AND EXPANSION 17

Works. At the same time the two small lean and rich gas containers that had
gone into operation in 1928 were replaced by new constructions in new
places on the Hansa site.
In July 1968 the first coke was pressed out a new thirty-oven battery (“battery
0”) south of battery 1. Now the Hansa coking plant comprised over 314
ovens and had reached its maximum output capacity of 1,900,000 tons a
year. In 1976 batteries 0 and 1 were given their own quenching houses in
order to lower the levels of dust emissions when the coke was pressed out of
the ovens. In 1982/83 a dry quenching plant for the coke was constructed
as an alternative to the water cooling in the quenching towers. Despite the
The coking plants were strategic war targets because they were vital
cornerstones for steel production in the Nazi rearmament and autarchy
policies. Batteries 1 and 2 at the Hansa coking plant were so heavily
damaged that they had to be demolished and replaced with new ones
in the 1950s. Photo: 1944
The post-war years were devoted to cleaning up the war damage. Batteries
1 and 2 were irreparably damaged and had to be demolished, and were
replaced in 1951 and 1955 respectively by new batteries each containing
62 ovens. In addition, there were further construction changes. As early as
1943 work began on building a generator house to produce lean gas from
the plant’s own small coke and low-quality coal to supplement the lean gas
supplied by the Dortmunder Union steelworks. The last of a total of 16 generators
went into operation in 1955. Between 1955 and 1959 parts of the coal
by-product plants were modernised and extended with the aim of being able
to produce as much coking gas as possible for long-distance supplies.
The Hansa coking plant was integrated into the Hansa Mining Company as
early as 1953, and this in turn was taken into the Ruhrkohle Company in
1969. A major organisational change came after extensions to the coking gas
pipelines were completed in 1964. Now Hansa took over responsibility for
supplying gas and coke to the Phoenix steelworks in the Dortmund suburb of
Hörde. From 1966 onwards, after the blast furnaces at the Dortmunder Union
steelworks were closed down, Hansa also took furnace gas from the Phoenix
huge number of extensions,
most of the essential elements
in the original plant
built in 1928 have been
retained.
Repairs and extensions
continually took place
over the whole site
during its 64 years of
operation. In 1955 the
“white side” was extended
with the addition
of new benzene stepby-step
scrubber.
Photo: 1955
In 1983 an experimental
KTK was built by the Carl
Still company north of the
batteries on the Hansa coking
plant This was later extended
and remained in
operation until 1992. The
plant could cool ca. 80 tons
of coke per hour. After 1986
this was approximately 50%
of production. Photo: 1983
18
HANSA COKING PLANT – THE HISTORY OF THE INDUSTRIAL MONUMENT
REARMAMENT AND EXPANSION
19

The end – and a truly
monumental new beginning
plants, and make a redevelopment study of the site. Finally, in 1998, the
Hansa coking plant was inscribed into the list of protected monuments in
the city of Dortmund. This did not, however, apply to the whole site but only
to the most essential elements dating back to the 1920s and 1930s.
The last coke was pushed out of the ovens on the Hansa coking plant
on December 15th 1992 in a solemn and somewhat poignant final
ceremony. Over the years the workers had developed an affectionate
relationship to the Hansa coking plant despite the harsh working
conditions. Photo: 1992
In 1986 batteries 0 and 4 were taken out of production, and on the 15th
December 1992 the last batch of coke was pressed out of the ovens and the
Hansa coking plant was closed down for good. Its production – along with
some of the workforce – was moved to the modern Kaiserstuhl coking plant
which went into operation on the 1st December 1992 on the site of the
Westfalenhütte steelworks in Dortmund.
On the 3rd December 1992, immediately before Hansa closed down, staff at
the Westphalian Office for Monument Preservation put forward proposals to
list the Hansa coking plant as an industrial monument. Five years later work
began on a comprehensive study to evaluate the individual buildings and
The value of the Hansa coking plant as a listed monument consists in the fact
that most of the buildings and technical plants are authentic documentary evidence
of the state of coking technology in the 1920s. The clear architectural
design of the buildings, their strict arrangement according to the process of
production, and their ability to accommodate potential extensions with ease,
clearly reflect – despite later modernisation phases – the “classical” demands
made on the industrial buildings of the modern age. These demands are still
basically valid today. Furthermore the Hansa coking plant is the last extant
major coking plant from the 1920s in the Ruhrgebiet to systematically integrate
the production output from a colliery, a coking plant, a steelworks, and
the long-distance gas grid. The compressor house is of particular value for
its five pairs of steam-driven gas compressors dating back to 1927/28 and
1941/42 respectively. Alongside the historical technical and architectural
aspects, the urban planning significance of the industrial site in connection
with the growth of the suburb of Huckarde is also a relevant factor in its
value as a listed monument.
Closed. When the Hansa coking
plant was taken out of operation
in 1992 its future as an industrial
monument was not yet secure.
Photo: 1993
20
HANSA COKING PLANT – THE HISTORY OF THE INDUSTRIAL MONUMENT
THE END – AND A TRULY MONUMENTAL NEW BEGINNING 21

Good times
The decision to preserve the Hansa coking plant for future generations was
taken at a boom time for industrial monument conservation in the state of
North-Rhine Westphalia. Comprehensive programmes and tools for preserving
and redeveloping industrial monuments were created on the basis of the careful
use of resources and their sustainability. At the same time, since the mid-
1970s, increased value was put on documenting, researching and mediating
the industrial history in North-Rhine Westphalia. This led, amongst others,
to the establishment of the Westphalian Industrial Museum in 1979, and the
Rhineland Industrial Museum in 1984.
Another milestone was set between 1989 and 1999 with the Emscher Park
International Building Exhibition, a programme intended to accompany and
master the problems of structural transformation of a region based on heavy
industry to one based on service and information. The International Building
Exhibition made a huge contribution to the conservation of industrial buildings
and, at the same time, shone a public spotlight on the theme of industrial
history and culture. Its successes speak for themselves. The former ironworks
in the Duisburg suburb of Meiderich is now an industrial landscape park
which attracts huge amounts of visitors. The Gasometer in Oberhausen and
the mixing plant in the Zollverein mining complex in Essen are uniquely
compelling exhibition venues for arts and culture. The initial ideas to set up
an Industrial Heritage Trail, as a tourist attraction connecting all the most
important industrial venues in the Ruhrgebiet in a 400 kilometre circuit, also
date back to the 1990s.
A further unique institution nationwide is the Foundation for the Preservation
of Industrial Monuments and Historical Culture which was set up in 1995. It
is committed to preserving first-class industrial monuments with the aim of
protecting them from abolition, securing their existence, researching the
The “Vitale Areale” show heralded in the era of the Hansa coking plant as an
industrial monument. The photo shows a scene from “Three Sisters” by Anton
Chekhov. Photo: 1999
history, making them accessible to the general public and redeveloping them
for new uses corresponding to their listed status.
The Foundation for the Preservation of Industrial Monuments and Historical
Culture is responsible for many different mining sites in North Rhine Westphalia.
These include the Hansa coking plant, whose historical administrative
buildings have contained the organisation’s business headquarters since
1997. Two years later, on the 1st April 1999, the Hansa coking plant was
opened as an anchor point along the Industrial Heritage Trail. For the first time
tourists were able to explore the monument along a theatrically staged adventure
trail during a major celebratory event entitled “Vitale Areale – Forum Interart”.
There was a huge positive reaction from the general public. No less
than 10.000 visitors poured into the site to explore the once “forbidden city”.
22
HANSA COKING PLANT – THE HISTORY OF THE INDUSTRIAL MONUMENT
GOOD TIMES 23

Clever planning
The master plan foresaw the visitor trail, “Nature and Technology”, along with
a link from the coking plant to the “Deusenberg” spoil tip and an opening to
the suburb of Huckarde. Master plan: 2001
In 2001 the city of Dortmund commissioned the landscape architects, Davids,
Terfrüchte and Partners, to produce a master plan for the development of the
Hansa coking plant. With reference to a study made by the Westphalian Office
for Monument Conservation in 1997 the master plan came out in favour of a
tourist profile for the site, including the construction of visitors trails. The fundamental
aim was to develop the coking plant as a sort of “accessible gigantic
sculpture”. The design of several different areas foresaw an orientation towards
the central theme of “nature and technology”. Furthermore, urban components
were accentuated and proposals were made to open up the industrial plant
to the neighbouring suburb of Huckarde to the south and to the west, by integrating
new buildings. The proposal to link the monument with a regenerated
landfill site to the east by means of a pedestrian bridge also proved crucial.
Today the Deusenberg site is a popular venue for football and other sporting
activities. Plans are currently being made to build a ring road around the site.
The Hansa coking plant was at
first retained in its complete form.
Finally, however, only the listed
plants were preserved. This meant
that the gasometer, the second
coal tower and the coke dry
cooling plant had to be dispensed
with. Photo: 2002
Today the Hansa coking plant
comprises the basic buildings as
they were in the 1920s and 30s.
Photo 2008
The master plan was completed in 2001 on the assumption of preserving the
buildings on the coking plant as they were at the time of its closure in 1992.
In the years between, however, the number of buildings was considerably
reduced. The monument authorities basically concentrated their attention on
preserving the buildings and plants from the 1920s. This meant that a number
of different buildings and plants from later periods were demolished according
to the legal rights of their former owner, the RAG holding company. These
included the gasometer, coal tower II, screening plant II and the dry
quenching plant.
The reduction in the buildings on the Hansa coking plant and the corresponding
reduction in the overall ground area, made it necessary to adapt the master
plan to the new conditions. That said, the basic criteria for developing the
Hansa coking plant as a gigantic accessible sculpture remained untouched.
24
HANSA COKING PLANT – THE HISTORY OF THE INDUSTRIAL MONUMENT
CLEVER PLANNING 25

New paths
Several so-called monument paths for visitors were constructed at the Hansa
coking plant between 1998 and 2003. The Heinrich Böll architectural
office in Essen was commissioned to implement the building project. In three
building phases all the most important areas of production were linked by a
system of paths consisting of accessible conveyor bridges, pipeline bridges
and ramps. In order to open up the maximum number of different perspectives
the monument was also made accessible on different levels. Visitors can now
move around the ground area on the ring road surrounding the monument,
and learn more about the structure of industrial production on the “black side”
where the coke was produced, and the “white side” when the gas was
processed into by-products. A further path provides access to the heart of the
coking plant, the coke ovens, and leads over to the white side containing the
“chemical factory”. A third trail leads visitors along the path of coal to the
coke oven batteries via conveyor belt bridges and past imposing accessible
coal bunkers.
“Transparent” conveyor bridges and panoramic windows enable visitors to
get fascinating views of the industrial plant and offer them the chance to get
their bearings in the industrial plant with respect to the suburb of Huckarde
and the city of Dortmund.
No matter which paths visitors choose to take, the compressor house with its
valuable collection of historical technical engines is always a high point along
the circular tour. Apart from producing coke, the gas released by the coking
process was the second most important area of production in the Hansa
coking plant. The compressors made by the DEMAG company were used to
feed the coking gas into the Ruhrgas grid. They are important monuments to
the early long-distance gas production that took off in the 1920s, and mainly
supplied industry and domestic households with coking gas.
Visitors can acquaint themselves
with the Hansa coking
plant on the „Nature and Technology“
adventure trail. The
path leads via “transparent”
conveyor belt bridges, past
bucket elevators, through coal
bunkers to the coke ovens, and
via pipe bridges to the „white
side“, the „chemical factory“
on the coking plant.
Photos: 2003-2009
26
HANSA COKING PLANT – THE HISTORY OF THE INDUSTRIAL MONUMENT
NEW PATHS
27

Industrial nature is welcomed at the Hansa coking plant. Within
the space of a few years a birch grove has sprung up on the
“roofs” of the coke ovens. Photo: 2005
Roof gardens on the coking ovens
On their tour of the coking plant visitors can not only explore a number of
industrial legacies but also a coking plant in the midst of natural green surroundings.
Indeed the general development of the area is based on a highly
unusual concept with respect to monument conservation: to unite historical architecture
and technology with the untamed growth of “industrial nature” into
a new overall environment. The concept of industrial nature generally refers
to the flora and fauna growing on disused industrial sites. New man-made
landscapes have been built up in places like collieries, coking plants and
steelworks due to the amassment of slag, dead rock, dust, ashes and building
rubble. The resulting ground can only absorb small amounts of moisture and
contains very few nutritive substances. In addition, a large proportion of dark
materials like coal dust mean that the ground warms up much more quickly
under sunlight than other more typical grounds in the region. Despite the
man-made terrain there are a large number of different species of plants and
animals which flourish on the difficult conditions inherent in disused industrial
spaces. The resulting areas of industrial woodland are now under the supervision
of a forestry officer employed by the Foundation for the Preservation
of Industrial Monuments and Historical Culture to care for the “Ruhrgebiet
industrial woodland project”. This is not a forestry business in the traditional
sense of the word. It rather prefers to abandon the site to natural forces,
thereby allowing plants and animals to develop, for the most part free of
human intervention or influences.
The Hansa coking plant is not only an anchor point along the tourist Industrial
Heritage Trail in the Ruhrgebiet, it is also part of the “industrial nature” theme
trail and, in addition, since 2006, a part of the European Garden Heritage
Network. As a result, further redevelopment plans are being drawn up during
the coming years on the existing basis of “nature and technology”. Several
concrete plans now exist: a “forestry station” is to be constructed in the former
warehouse building. It will contain an exhibition space to illustrate themes like
the environment, sustainability, nature, society and power, especially with a view
to catering for school groups. Furthermore it is planned to turn the former laboratory
building and its historic equipment in the Hansa coking plant into a “paint
laboratory” for children, equally dedicated to producing paints from plants as
well as from the by-products directly associated with the old coking plant.
28
HANSA COKING PLANT – THE HISTORY OF THE INDUSTRIAL MONUMENT
ROOF GARDENS ON THE COKE OVENS 29

Rain collectors and cloud makers
Even during the time it was in operation the Hansa coking plant was a sort
of laboratory for technical improvements. These included the construction of
a quenching house and a dry quenching plant. The current owner of the
coking plant, the Foundation for the Preservation of Industrial Monuments
and Historical Culture, also makes no bones about its open attitude towards
technical innovations. In 1999, in recognition of a new generation of regenerative
power – it built a photovoltaic plant on a building in the coking plant on
the Zollverein World Heritage site in Essen. The plant is still run by the Foundation
and now has an output of ca. 218,000 watts. The Foundation is planning
to join forces with the “Emschergenossenschaft” for a further innovation –
a hydraulic power project at the Hansa coking plant as part of an agreement
to promote rainwater in the future. This agreement represents a common
commitment made by all the towns and cities in the Emscher area, the Ministry
for the Environment and the “Emschergenossenschaft“ to lower the demands
made on the sewage system by 15% in the next 15 years by the use of rain
and pure water. This challenging target means that pure water will then no
longer be unnecessarily conducted to the clarification plants, but put straight
back into the natural water circulation. Rain falling on the Hansa coking plant
will be collected in a special basin and in specially paved surface conduits
leading to reservoirs by the old cooling tower. The rainwater will then be
warmed up by the photovoltaic solar panels installed there, and evaporated
around 30 to 40 times a year in the form of a visible cloud of steam rising
into the sky.
Perhaps clouds of smoke will soon be rising once again into the sky above
Hansa, when rainwater collected in the basins of the cooling tower is heated
up and evaporated. Project simulation: 2010
30
HANSA COKING PLANT – THE HISTORY OF THE INDUSTRIAL MONUMENT
RAIN COLLECTORS AND CLOUD MAKERS 31

tecture and technology, via industrial work, working clothes, language, coal
and coke, all the way to monument preservation and new artistic uses. The
projects inspire the young students to do their own research in a familiar
environment, to communicate with parents, grandparents and neighbours,
question them as contemporary witnesses about mining and factory work, and
get acquainted with people’s recollections as an important source of historical
legacies. Furthermore the students are motivated to bring their own exhibits
into the classroom: things like a miner’s helmet, an old working glove, a butter
dish, photos or newspapers. In this way they learn to put a value on everyday
industrial objects. Lastly, art lessons give them the opportunity to work on
these “memoirs” and enrich them with their own personal impressions and
imagination. They can then recount new “stories” on the basis of the old ones.
The Hansa coking plant has proved its worth as an extra curricular
place of learning. Every year on the open day, school students
from the Gustav Heinemann comprehensive school in Dortmund
exhibit the results of their projects. Photo: 2005
Since 2005 the Foundation for the Preservation of Industrial Monuments has
been co-operating with the Gustav-Heinemann comprehensive school in the
suburb of Huckarde, on projects that are presented at open days in the form
of an exhibition in the compressor house at the Hansa coking plant. In 2008
the school students won a national competition with a project entitled “The
Rusty Gardens in the Hansa Coking Plant”
An extra curricular place of learning
For some years now the Hansa coking plant has been used as an extracurricular
place of learning. During project weeks school students study the Hansa
coking plant in order to get to know it in more detail. They collect impressions
of the local suburb by observation, photography and drawing. The "images"
of coal towers, machines, pipelines, plants and animals later serve to jog their
memories as a basis for further work, for example, in art lessons. The Hansa
coking plant offers a huge spectrum of themes ranging from industrial archi-
32
HANSA COKING PLANT – THE HISTORY OF THE INDUSTRIAL MONUMENT
AN EXTRA CURRICULAR PLACE OF LEARNING 33

The art lab
The Hansa coking plant is not only a magnet for people interested in technology
and nature. Since it first opened in 1999 artists have been continually
seeking a dialogue with the monument in order to gain inspiration from its
industrial past and structural transformation.
The owner of the coking plant, the Foundation for the Preservation of Industrial
Monuments and Historical Culture , which is simultaneously responsible for
preserving, researching and opening up the site for new uses, regards artistic
activities as an enrichment to its programme of events and to “staging” the
site. Artistic contributions can also provide critical comments and questions
regarding the Foundation’s concepts, as well as on factors like building and
landscape planning, and redevelopment. At times they might even be able
to reformulate such concepts. In this way artistic reflections on the past and
present history of the monument are part of a process of development which
demands an open-ended dynamic approach.
Art projects are a basic part of the development process at the Hansa coking
plant. In the exhibition “Forbidden City” Stefan Sous presented his project
“Smoke – new sandalwood aroma” in the compressor house to demonstrate
the process of transformation from an industrial plant to a monument adapted
for new uses. Photo: 2002
In the exhibition entitled “Speed” Caspar
Pauli drew his inspiration from material flow
and changes, as well as from the building
structures at the coking plant. Photo: 2009
34
HANSA COKING PLANT – THE HISTORY OF THE INDUSTRIAL MONUMENT
THE ART LAB
35

A well-preserved monument
Preserving the Hansa coking plant for future generations is an awesomely
responsible duty. It is not only about preserving the buildings but also the
complex technical equipment and plants. The original architect of the coking
plant, Hellmuth von Stegmann und Stein (1891-1929), was only too aware
of the importance of engineering aspects when taking account of the overall
impression made by an industrial plant. He felt it was necessary to “be clear
about the fact that purely engineering constructions like storage tanks, chimney
stacks, chamber coolers, large-scale pipelines etc, are very often at least
as important in creating an overall impression of an industrial plant as the
aesthetics […] of the buildings. On many occasions a well thought-through
concept on how to arrange the buildings containing the machines and
engineering equipment is much more important than a purely formal arrangement
of high buildings, however successful this might be.
A huge responsibility. The preservation of the Hansa coking plant industrial
monument. Not only the buildings but also the technical equipment have to
be conserved. Photo: 2008
The Foundation agrees with this opinion entirely and this is why it has decided
to devote its energies to preserving as many of the technical and engineering
buildings as possible in order to document the history of the technology, production
and the economy, not forgetting the ideal overall impression of a typical
industrial plant in the 1920s.
The many containers and pipelines
that make up the “arterial system”
of the coking plant should also
be preserved where possible.
Photo: 2003
36
HANSA COKING PLANT – THE HISTORY OF THE INDUSTRIAL MONUMENT
A WELL-PRESERVED MONUMENT 37

The gas compressors were completely cleaned up in 2006. They are the highlight of
every tour. During a guided tour visitors can watch one of the gas engines in action.
Photo: 2005
At first the Foundation assumed that parts of the plant like the coke oven
batteries, storage tanks and pipelines should be successively allowed to fall
into a controlled state of dilapidation, and many ideas were thrown around
concerning the picturesque images of overgrown oven ruins. But these ideas
were not pursued further because those in charge realised that allowing the
side to fall into a controlled state of disrepair would be tantamount to a continual
process of dismantling. The corroding and collapsing parts of the site
could not simply be left to themselves and natural influences, because this
might very well result in ground pollution. If so, it would be impossible to
allow the ruins to remain on the site and they would have to be removed.
The monument would therefore gradually disappear.
huge monument can only take place step-by-step – not least for financial
reasons – and therefore needs years of hard work, the Foundation for the
Preservation of Industrial Monuments and Historical Culture has opted to deal
with specific sections of the site, like the construction of visitor trails. The primary
consideration was to ensure that the whole site was accessible to visitors.
As result the aim was to develop a system of paths which was not only
safe, but also linked all the most important areas of production in the coking
plant. Thus cleaning up the areas beyond the trails, like the facades of the
coal towers, could be postponed or even entirely disregarded. The same
applied to the interior of the building which, like the coal bunkers, were also
only “parsimoniously” cleaned up. Many visitors found this approach extremely
attractive because the view from the trails allowed them to get a view
of areas still blackened with coal dust which seemed to have been left almost
untouched. This allowed them to get a much closer and intimate idea of the
industrial history of the site. The resulting atmosphere has played a very important
part in producing an emotional response to the coking plant and this
has resulted in an increased interest in the work that once took place here.
The approach to the compressor house at the Hansa coking plant was utterly
different. The building was completely cleaned up, the valuable collection of
engines restored, and an area created for events. The fresh white coat of
paint given to the interior walls of the building underlines its museum atmosphere
and the new uses to which it can be put.
The overall concept behind conserving the Hansa coking plant is clearly not
static, but dynamic and open. Here concepts for landscape designs, partial
redevelopment, complete redevelopment, basic safety measures and overall
care stand alongside one another in a flexible framework. Last not least,
funding problems demand that we adopt such an approach. The individual
building blocks and strategies for dealing with the monument all mesh in
together and – even in their apparent contradictions – this is what makes the
challenges involved in preserving the coking plant so exciting.
Many different strategies are being pursued to preserve the Hansa coking
plant, all of which are part of an overall plan. Because cleaning up such a
38
HANSA COKING PLANT – THE HISTORY OF THE INDUSTRIAL MONUMENT
A WELL-PRESERVED MONUMENT 39

From coal to coke –
a trip through the production
process in a coking plant
What is a coking plant – a brief introduction
In a coking plant coal is loaded into hermetically sealed chambers and
heated to high temperatures in coking ovens arranged in batteries of several
dozen narrow chambers. The coal is then baked in the ovens for around
twenty hours at over 1000 degrees Celsius and the so-called “volatile materials”
are drawn off. This process results in coke .Because of its higher carbon
content, its purity and its calorific solidity coke is a more valuable fuel than
coal. This is why it is primarily used for fuelling blast furnaces producing pig
iron in steel and ironworks
One by-product of the baking process is the crude gas which is then siphoned
out of the ovens. The crude gas not only contains pollutants like hydrogen
sulphide but also ammonia, crude benzene and tar. These so-called by-products
are then separated from the gas in further production steps. Some of
them are cleaned up and sold on as valuable products on the market. When
coke production in Germany was at its height the by-products were important
basic materials for the chemical industry. The cleaned up coking gas – it was
known as rich gas – was sold off as fuel for steel mills and other industrial
factories, or as domestic gas in the Ruhrgebiet. Gas production was a lucrative
business for the coking industry until the mid-1960s when gas suppliers
gradually rejected it in favour of natural gas.
The production process in a coking plant is primarily divided into two main
areas. The buildings used for handling the coal and producing the coke
are known as the “black side”, and the by-products from the coking gas are
separated and cleaned up in the buildings on the “white side”. The buildings
in the Hansa coking plant make it possible for visitors not only to follow the
process of producing coke, but also to get a greater understanding of the
subsequent processing of the coking gas into its by-products.
The production process in a coking plant never stops. For this reason all the
activities including the workers’ shifts have to fulfil a single aim: to ensure
that there are no stoppages whatsoever. Once a battery of coke ovens has
been heated up – a process that often takes several months - it must in no
circumstances be allowed to cool down again, otherwise this will result in
irreparable damage to the walls of the battery. Minor interruptions in the
pressing process, or defective parts must be remedied or replaced whilst the
battery is still in operation. This demands a high level of efficiency not only
from the mechanical parts involved, but also from the workers involved in
maintaining them.
We shall now describes the path of coal and the path of the crude gas as
they pass through the various areas of production in the Hansa coking plant;
beginning with coal deliveries, continuing with the baking process and ending
with the finished coke and its by-products. The Hansa coking plant provides
an ideal example of the complex processes involved in such an industrial site.
40
HANSA COKING PLANT – THE HISTORY OF THE INDUSTRIAL MONUMENT
FROM COAL TO COKE 41

The coke oven battery
The various sorts of coal were
crushed and mixed in the
sorting tower. The so-called
coking coal was then transported
via a bucket elevator
to the coal tower, from where
it was driven to the ovens in a
charging wagon. This picture
shows the coal tower (centre)
with a charging wagon beneath,
and the sorting tower
(right). In the foreground,
the oven roof with the filling
holes. Photo: end of the
1920s
The coke oven batteries
and the coal tower are the
technical and architectural
heart of the “black side”.
Photo: end of the 1920s
The path of coal
Delivery
When the Hansa coking plant was running at
maximum capacity workers were able to produce
around 5,200 tons of coke per day from 7,000
tons of coal. This meant working round the clock
and constant deliveries of fresh coal. The coal was
delivered from the nearby Hansa colliery and from
two other Dortmund collieries, Westhausen and
Adolf von Hansemann. Coal from the Hansa colliery
was delivered via a conveyor belt – known
as the Hansa belt – which led directly into the
Hansa corner tower on the site of the coking
plant. The other collieries delivered their coal to
the coking plant by cable car until 1945, and subsequently
by rail.
In order to produce high-value coke it is necessary
to blend different sorts of coal into a specific mixture.
For this reason the coal has to be specially
prepared before it is baked into coke. Coal exists
in several different qualities that are graded,
amongst others according to the amount of volatile
by-products they contain. The coal is not sorted
before it leaves the collieries but is simply delivered
on conveyor belts to the bunkers next to the sorting
tower in the coking plant. The first step in the process
of producing coke is therefore to mix the different
grades of coal correctly. Once it has been
mixed it is taken from the sorting tower to the coal
towers above the coke oven batteries. If necessary,
the mixture of coal can be crushed down into even
finer nuts.
The coking process took place in the coke ovens.
The individual oven chambers were all contained
in a single battery because this was the most efficient
way of heating and controlling them. During
boom periods of production there were five batteries
at the Hansa coking plant comprising a total
of 314 coke ovens. Every single oven chamber is
a narrow walled space consisting of highly efficient
heat-conducting silicone bricks. At Hansa the ovens
were 13 metres long, 4 metres high and only 41
centimetres wide. The sides of the ovens were
hermetically sealed by cast-iron doors.
A mixture of combustible gas and air is burnt in
the walled-up hollow spaces – so-called combustion
walls – between every two ovens. In the regenerative
ovens that began to predominate in 1911,
the combustion air was first warmed in heated
stone constructions beneath the ovens, known
as regenerators. This meant that much less selfproduced
gas was needed to heat the ovens to
the desired temperature of 1,250 degrees Celsius.
In addition regenerative ovens enabled the ovens
to be fired with furnace gas instead of the more
usual rich gas. At Hansa, furnace gas was taken
from the nearby steelworks and supplemented with
a certain proportion of self produced rich gas.
Charging wagons were responsible for loading the
oven chambers. They ran on railway lines along the
roof of the batteries beneath the coal tower where
they were loaded with around 15 tons of coal.
During this time a worker standing on the roof of
the ovens that were due to be filled, would open the
five filling holes in the oven roof with the help of a
hook. The charging wagons would then be driven
In order to guarantee a constant
temperature level in the ovens
the hollow spaces in the heating
walls had to have a particular
shape. An oven chamber
(centre), flanked by two heating
flues. Photo: the 1920s
The filling wagon was driven
over the battery by electricity,
and dropped its load of coal
into the ovens through a conical
opening. During this process air
and some of the first coking gas
with its dangerous substances
escaped. Starting in the 1970s
a special wagon was docked at
Battery 4 to suck off any crude
gas that might escape. Photo:
the 1980s
42
HANSA COKING PLANT – THE HISTORY OF THE INDUSTRIAL MONUMENT
THE PATH OF COAL 43

Any damage to the walls of
the coking ovens was repaired
during running operations.
To do this the workers were
fitted out with protective clothing.
Nonetheless they had
to endure incredibly high
temperatures. The workers
even had to intervene when
the coke blocked up as it
was being pressed out of
the ovens. For this they got a
so-called “de-blocking” bonus.
Photo: end of the 1960s
above the holes from where they would empty the
coal through conical inlets in the ovens. If any coal
happened to land on the roof of the ovens one of
the workers would sweep it back into the ovens by
hand. The filling holes were then closed and sealed
with a claylike mass poured around the lid. The
filling process causes so-called “filling cones” in the
ovens, similar to the small cones of sand which
build up when you let it run through your fingers.
For technical reasons, however, the surface of the
coal must remain even because an empty space
above the coal is needed to collect the gas resulting
from the coking process. For this reason the pressing
machine would then open up a small flap on
top of the oven and insert a so-called leveller bar
into the oven to level out the cones of coal caused
by the filling process. The flap would then be closed
and coking could begin.
The mixture of coal was heated in hermetically
sealed oven chambers at temperatures of over
1000 degrees Celsius for around 20 hours, during
which time the volatile materials – around one
quarter of the charge – were removed. Thus one
ton of coal resulted in around 750 kilograms of
coke. The volatile materials in the crude gas were
caught in rising pipes and collecting mains, and
conducted to the white side of the production plant
to produce the by-products of crude tar, crude
benzene, sulphuric acid and ammonium sulphide.
More in the chapter entitled “The Path of Gas”.
The coke pusher engines and the
quenching wagons
When the coke cake, as the molten coke mass
was called after it had been baked, was ready, the
pusher ram or coke pushing machine came into
operation on the machine side (hence the name).
First it unlocked the oven door, pulled the door out
of the opening and moved it to one side. Then it
inserted a long rod, at the front of which was attached
a pusher head, into the oven and pushed the
coke out through the other side. After that it closed
the door once more. Fresh batches of coal could
then be fed into the ovens once more from above.
It goes without saying that the ovens were also
opened on the opposite side – the coke side. This
was done by a coke cake guide car. Just like the
pusher ram it unlocked the door and lifted it out to
one side. After that it placed a steel guiding device
in front of the oven to ensure that the entire coke
cake fell into the quenching wagon. Both the pusher
ram and the coke cake guide car were driven by
a single engineer. Later the two engineers could
coordinate their work by radio.
The quenching tower
The coking process in the oven chambers can only
take place if they are hermetically sealed. If there
is any oxygen in the oven chambers the coal will
simply burn and not be baked to coke. As soon as
the molten coke leaves the oven, of course, it comes
back into contact with air and catches fire immediately.
To prevent it burning to ashes it has to be
cooled down as quickly as possible: or to use the
workers’ jargon, “quenched”. This explains why a
quenching wagon is standing ready to transport the
molten coke to the quenching tower as soon as it is
The finished coke known as
“coke cakes” was pushed
out of the ovens by pusher
engines. This took place
every 7 minutes according to
a fixed scheme. Photo: 1950s
When the molten coke came
out of the oven it caught
fire immediately. This is why
it had to be transported to
the quenching tower.
Photo: 1968
“Cloud makers”. Every time
coke was quenched at the
coking plant a huge cloud of
smoke rose up into the sky.
Photo: 1992
44
HANSA COKING PLANT – THE HISTORY OF THE INDUSTRIAL MONUMENT
THE PATH OF COAL 45

After it had been quenched
the coke was tipped out onto
the ramp to cool down. Any
remaining fire was quenched
by hand by the ramp man
with the aid of a simple hose.
Photo: the 1920s
After the coke had been completely
quenched it was taken
to the screening plant
to be sorted into different
sizes before being loaded
into railway wagons and
transported to the steelworks.
Photo: the 1920s
pushed out of the oven. The quenching tower is a
construction made of concrete and timber, beneath
which the burning coal is quenched with sprays of
water. This process produces a characteristic cloud
of steam that billows out above the coking plant. At
the Hansa coking plant this occurred every seven minutes
when production was at its height.
A dry quenching plant is another way of cooling
down the coke after it has been pushed out of the
oven. These are quenching plants in which a cooling
gas, like, for example, the inert gas nitrogen, is passed
over the molten coke. The advantage of the dry
quenching method is that the heat in the molten coke
does not evaporate into steam but can be recaptured
in the gas and used elsewhere. That said, such a
plant involves a huge investment, and the running
costs are also considerable. This is why it only pays
to use dry quenching equipment under very particular
preconditions.
After the coke had been quenched the quenching
wagon would return to the oven battery to tip out the
quenched coke onto a ramp. This is where the ramp
man worked, who had to check to ensure that all the
molten mass had been quenched. If this was not the
case, he had to put out any remaining burning coke
with a hosepipe. After the coke was completely
quenched it would be left for roughly half an hour to
cool down on the ramp before being transported on
a conveyor belt to the screening plants. Here the
coke would be broken up and sorted into different
sizes and then loaded onto railway wagons.
The path of gas
Drawing off the crude gas
We have already mentioned that coking coal produces
a by-product known as crude gas. Each full
oven charge produced around 5,200 cubic metres
of gas: at the Hansa coking plant this amounted to
around 95,000 to 100,000 cubic metres of gas
per hour. The gas collected in the space above the
red-hot coal in the ovens. Each oven and chamber
was equipped with a vertical upward pipe to draw
off the crude gas during the coking process. Large
gas exhausters transported the crude gas via tapping
conduits and gas collectors to the gas preparation
buildings on the white side of the coking
plant. Here the by-products were separated from
one another and the gas was prepared to be fed
into the long-distance gas grid. On average one
ton of coke would produce 40 kg of crude tar, 8
to 10 kg of crude benzene and 3 kg of ammonia.
Producing the by-products tar and phenol
As soon as the hot crude gas had left the oven via
the conduit pipes it was cooled down to around
90°C in the elbows of the pipes by spraying it with
water. This process produced the first by-product:
crude tar, which was dissolved in the condensed
coal water and conducted with the crude gas
through the conduits. The condensed steam was
captured in a funnel in the so-called tar extractor.
The heavy solid matter was deposited here, and
the dissolved tar was separated from the water by
a “Koppersche” pressure separator. At Hansa,
minuscule particles and aerosols remaining in the
crude gas were removed in the electric gas purification
plant, which consisted of four electro-filters.
The crude gas was taken
from the coke ovens via a
pipeline to the “white side”.
This process was regulated
and controlled by a worker.
This picture was taken at
one of the Hibernia coking
plants. Photo: the 1950s
46
HANSA COKING PLANT – THE HISTORY OF THE INDUSTRIAL MONUMENT
THE PATH OF GAS 47

The huge number of by-products
from crude gas. For
many years coking plants
delivered important basic
materials in the form of their
by-products, most especially
to the chemical industry.
All the tar fractions were then purified once again
and collected in tar containers. The tar was then
taken in tar tank wagons to the Rüttgers works in
Castrop-Rauxel. Around 40 greater kilograms of
tar could be produced from one ton of coke.
Once the tar had been separated from the water,
the water was led back to the conduit elbows and
sprayed onto the crude gas. Since the coking process
also produced extra water that was drawn off
via the rising pipes and taken to the white side,
some of this water had to be removed from circulation.
The surplus water was not only poisonous to
fish but carcinogenic. So it first had to be fed into
the “Emschergenossenschaft” dephenolating plant.
Here the poisons and carcinogenic phenol were
removed and passed on as raw materials to the
chemical industry. The water was now free of
phenol and could therefore be taken to the pump
works and clarification plant in Deusen, from where
it was released into the River Emscher.
further stage of gas purification, the hydrogen
sulphide washer where it was once more sprayed
with water. Here too gas streamed from the bottom
to the top and the remaining hygiene sulphide
particles were bound together by the ammonia
water. The resultant solution of ammonia and hydrogen
sulphide which also contained carbon dioxide,
was finally sent to the wash water distillation plant.
This produced distillation steam which was then
taken on to a sulphuric acid bath to be turned into
ammonium sulphate. The rest of the mixture was
taken on to the sulphuric acid plant where the
hydrogen sulphide was turned into sulphuric acid.
The gas had now been freed of ammonia and
hydrogen sulphide and was taken to the benzene
washer where it was freed of its crude benzene
by the usual spraying method, albeit here with a
special creosote scrubbing oil. The mixture of
benzene and oil was then distilled to produce the
final by-product: benzene.
Several different “cleansing”
stages were necessary in the
so-called multi-stage washers
on the “white side” in order to
separate the by-products from
the crude gas. Photo: the 1950s
Ammonia, hydrogen sulphide and benzene
Once the tar and phenol had been removed from
the crude gas, the latter was taken to the pre-coolers
– a system of stacked up water-cooled pipes – and
cooled down to around 25° Celsius before being
sent on to the multi-stage washers. The gas flowed
from the bottom to the top whilst it was being
sprayed with water from above. Furthermore the
ammonia washer only used pure softened water.
Here the contact between the drops of water and
the gas bound the ammonia and pulled it down -
wards, whereas the gas continued to stream upwards
to be taken to the next stage of washing.
The mixture of water and ammonia collected at
the bottom of the washer and was also taken to a
In the 1950s and 60s the purified by-products
produced in coking plants were important raw
materials for the chemical industry because they
could be used to make synthetic paints, synthetic
materials, preservatives and also medicaments.
Ammonium sulphate was used as a dunging salt
and many farmers in the region used to buy it
directly from the coking plant. But in the 1970s a
change in the market situation led to a change in
the production of by-products. Nowadays, for
example, in modern plants ammonia is split into
H2 and N2 and fed back into the crude gas,
because the by-products of hygiene and nitrogen
are no longer profitable on the open market.
48
HANSA COKING PLANT – THE HISTORY OF THE INDUSTRIAL MONUMENT
THE PATH OF GAS 49

The powerful compressors
in the compressor house
compressed the gas before
it was taken to the grid.
Originally the compressor
house was equipped with
three compressors, but in
the 1930s another two were
added. Today the house with
its compressors is the core
of the Hansa coking plant
industrial monument.
Photo: 2008
Compressing and cooling
After the by-products had been cleaned and
separated, the coking gas was sold off to different
purchasers. From 1931 onwards the Hansa coking
plant sold the rich gas produced in the coking process
to the nearby Dortmunder Union steel works,
and later also to the Phoenix steelworks. The socalled
“Union blower” in the building north of the
compressor house was responsibile for supplying
gas to the steelworks. This required very little
compressed gas to be able to “blow” it over to the
steelworks. The quality of the gas supplied to the
steelworks was equivalent to the quality of the
rich gas heating gas. It was known as “partially
cleaned” gas.
Some of the coking plant gas was also fed into
the long-distance gas grid and sold as town gas to
households in the Ruhrgebiet. In order to transport
it into the connected gas grid the gas had first to be
compressed in the coking plant. The compressor
house in the Hansa coking originally contained
three, and later five, large gas compressors made
by the Demag company. These compressed the gas
to a pressure of 8 at. Before it was fed into the
long-distance gas grid the Ruhrgas company demanded
that it be further cleaned up and cooled
to a dew point of under 5° Celsius.
centre has a capacity of 350,000 cubic metres).
It was damaged during the Second World War
and collapsed during a storm whilst being repaired
in March 1949. Construction work on a new
identical gasometer was completed in 1951. All
in all the Hansa coking plant had six very different
gasometers during its history, a smaller storage
holder for the furnace gas used to fire the ovens,
and several small gasometers alongside the large
one mentioned above, which was used to store
rich gas.
The integrated gas concept survived into the
1960 and 1970s before being gradually replaced
on the domestic market by natural gas. Nowadays
integrated production systems only exist between
coking plants and the iron and steel industry, other
industrial branches and the power industry.
The coking plant “giant”.
Superfluous gas could be
stored in this huge gas
container until it was delivered
to the grid. Photo: the 1950s
Since there were considerable variations in gas
consumption from the Ruhrgas grid it was necessary
to ensure that supplies were sufficient to meet peak
demands. In order to be able to deliver the required
amount to the grid, a 175,000 cubic metre disktype
gasometer made by the MAN company was
constructed in 1934. (By comparison the Oberhausen
Gasometer that is now used as an exhibition
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HANSA COKING PLANT – THE HISTORY OF THE INDUSTRIAL MONUMENT
THE PATH OF GAS 51

Chronicle of the Hansa
colliery and coking plant
in Dortmund-Huckarde
1856 After buying up eight coalfields in 1856 in the city of Dortmund
area and the parishes of Huckarde, Rahm and Deusen, the Dortmund Mining
and Ironworks Company consolidates (merges) them to create the 8.27
square kilometre “Hansa” mining rights area. Work on sinking the Weyhe
shaft begins, but is abandoned three years later.
1869 Mining begins with a workforce of 283. Link to the Cologne-Minden
railway line.
1875 Over 100.000 tons of coal are mined.
1889 Gradual takeover of the mining company by the Gelsenkirchen Mining
Company (GBAG). The takeover is completed in 1892.
1895 The first coking plant on the colliery site, with a total of 60 coke ovens.
1904 Modernisation of the surface buildings. 60 new coke ovens go into
operation in 1905.
1925 Closure of the coking plant.
1926 The GBAG is transferred to the United Steelworks Company.
1927 Construction begins on the Hansa large-scale coking plant north of
the colliery, the by-products to be manufactured on the same site.
1928 Production begins at Hansa with two coke oven batteries. The
nearby Dortmund Union Steelworks begins to supply the coking plant with
furnace gas.
1938-1941 Extensions to the coking plant with batteries 3 and 4.
Hansa now possesses 290 coke ovens.
1940 Firedamp/coal dust explosion with 52 mortalities. Battery 3 goes into
operation.
1941 Battery 4 goes into operation. Hansa is now the largest coking plant in
the Ruhrgebiet.
1944 Firedamp explosion with 94 mortalities.
1945 Heavy air raid damage to the colliery and coking plant, as a result of
which coking production is halted on 3rd of February. Batteries 3 and 4 are
fired up once again in August.
1949 Construction of a coal conveyor belt bridge from the colliery to
the coking plant.
1955 The modernised battery 1 goes back into operation. Hansa is now
one of the largest coking plants in Europe.
1957 The Hansa coking plant records its highest annual production,
around 1.864.000 tons of coke, with a workforce of 782.
1967 A major demonstration against the planned closure of the Hansa
colliery on the 21st of October in Huckarde is successful.
1968 Setting up of the Rheinelbe Mining company. Battery 0 is fired up.
1969 The colliery is transferred to the Ruhrkohle Mining Company which
had been set up in 1968. The coking plant is separated from the colliery
and put under the direction of a new coking plant company.
1980 The Hansa colliery is closed down.
1983 Construction of the coke dry cooling plant.
1986 Battery 4 is closed down.
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53

1991 The former workshop building (“the old Forge”) at the Hansa
colliery, originally built in 1903, is listed as a protected building.
1992 Closure of the Hansa coking plant. Production is transferred
to the new; Kaiserstuhl III coking plant.
1997 The Foundation for the Preservation of Industrial Monuments and
Historical Culture moves into its new business headquarters in the former
administrative building at the coking plant.
1998 The coking plant as it existed in the 1920s and 30s is listed. Work
begins on the construction of the adventure trail “Nature and Technology”.
1999 The Hansa coking plant industrial monument is opened to the public
for the first time. The coking plant is one of the anchor points along the
Industrial Heritage Trail.
2001 The administrative buildings are cleaned up and modernised.
2002 Completion of the adventure trail “Nature and Technology”.
2003 Illumination of the adventure trail “Nature and Technology”.
2004 Cleaning up of the compressor house and restoration of the
compressors.
2005 The large events square behind the compressor house is redesigned.
2007 Cleaning up of the workers’ washrooms, social building and the
central workshop.
2008 Cleaning up of the workshop building. The roofs on various
buildings are cleaned up.
2009 The entrance area of the coking plant is overhauled. Safety
measures are introduced in a number of buildings.
Further reading
Ahlers, Hubertus; Hoffmeister, Sabine and others.: Kokerei Hansa: Skulptur
Natur Kultur, ed. Stiftung Industriedenkmalpflege und Geschichtskultur,
Essen 2001.
Dahm-Zeppenfeld, Karin: „Rationalisierung entlastet nicht allein den
Menschen von schwerer Arbeit...“. Arbeitsplätze und Arbeitsbedingungen
an den Koksöfen des Ruhrgebiets vor und nach der Einführung von Großkokerein,
in: Hassler, Uta; Kohler, Niklaus (eds.): Das Verschwinden der
Bauten des Industriezeitalters. Lebenszyklen industrieller Baubestände und
Methoden transdisziplinärer Forschung. Berlin 2004; pp.167-173.
Kastorf-Viehmann, Renate: Die Kokerei Hansa in Dortmund-Huckarde als
Denkmal, in: Deutsche Kunst- und Denkmalpflege, 50 (1992), pp. 148-157.
Kierdorf, Alexander; Strunk, Joachim; Thomas, Hans Georg: Die Kokerei
Hansa. Kleine Geschichte eines Industriedenkmals, ed. Lehrstuhl für Denkmalpflege
und Bauforschung der Universität Dortmund, Dortmund 1995.
Kierdorf, Alexander: Architektur im Dienst der Technik. Die Baugeschichte
der Kokerei Hansa, in: Hassler, Uta; Kohler, Niklaus (eds.): Das Verschwinden
der Bauten des Industriezeitalters. Lebenszyklen industrieller Baubestände und
Methoden transdisziplinärer Forschung. Berlin 2004, pp. 175-189.
Osses, Dietmar; Strunk, Joachim: Kohle Koks Kultur, Die Kokereien der
Zeche Zollverein, ed. Stiftung Industriedenkmalpflege und Geschichtskultur,
Dortmund 2002.
Pfeiffer, Marita: Hansa-Panorama. Zur Geschichte einer Dortmunder Kokerei,
in: Heimat Dortmund, 1 (2003), pp. 36-39; id: Von schweren Hinterlassenschaften.
Über Gründung, Arbeitsweisen und Erfahrungen der Stiftung
Industriedenkmalpflege und Geschichtskultur, in: Die Denkmalpflege, 65. year
2007, vol 1, pp. 45-53.
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55

The Hansa coking plant –
an overview
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HANSA COKING PLANT – THE HISTORY OF THE INDUSTRIAL MONUMENT