European Bio-Energy Projects

TAR
MEASUREMENT
STANDARD
Objectives
So far, no well-developed and standardised
measurement method exists for tars in
biomass-producer gases, and different
sampling and analysis methods are
currently being used. In a previous
EU-project (ERK6-CT1999-20002),
a guideline for tar measurement
(‘the Guideline’) was developed in order
to remove this obstacle. The guideline aims
at the measurement of both gravimetric
tars as well as individual organic
compounds. The measurement principle
is based on the discontinuous sampling
of a gas stream containing particles
and condensable organic compounds.
The overall objective of the present project
is to expand the use of the guideline
and transfer it into a European (CEN)
standard method.
A standard for tar
measurement to enhance
implementation of biomass
systems
Challenges
Gasification processes, converting the solid
biomass feedstock to a gaseous fuel (or syngas),
significantly broaden the biomass utilisation
spectrum. The syngas can be used for, for
example, co-firing in coal-fired power plants,
electricity generation in stand-alone conversion
devices (gas engines, gas turbines, fuel cells), and
production of gaseous/liquid fuels or chemicals.
These applications set different specifications
for (the contaminant levels in) the syngas.
Organic contaminants or ‘tars’ are considered
as the major problem-causing contaminants,
which causes a large obstacle for the market
introduction of biomass-gasification based
systems. Measurement methods, as well
as definitions for tars, are numerous and nonconsistent.
As a result, the comparison of
data and the definition of clear maximum
allowable concentrations for tars in the syngas
still cause problems.
On the basis of a prior joint attempt by IEA,
US-DoE and EU parties to arrive at a common tar
measurement method (in the framework of a
previous EU project ‘Tar Guideline’), this problem
was tackled and a new measurement method
(Guideline) was developed. This method now
forms the basis for a standardisation procedure
at European level.
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Project structure
The work in this project is subdivided into two
activities:
• standardisation of the existing guideline into
a standard for measurement of tars in biomass
producer gases
• dissemination of the results.
In the first activity, standardisation is performed
in a task force (BT/TF/143) ‘Measurement of
organic contaminants (tars) in biomass producer
gases’ installed directly under the European
Committee for Standardisation (Comité Européen
de Normalisation, CEN). The task force is open
to representatives of each country affiliated to
CEN, and each representative/country has the
right to vote. The task force follows the work on
standardisation, basically consisting of meetings
to discuss draft versions and scientific content
of the standard. The participants of the ‘Tar
Measurement Standard’ project act in a double
role as national representatives in the task force
and also as technical experts performing R&D
activities, thus bringing in their expertise on tar
measurement and the use of the guideline to
define the specifications the standard has to
fulfil. In addition, the technical experts take
action to ensure collection of data that are still
missing. In particular, data on accuracy and
reproducibility of the draft standard are essential
in the process of standardisation. Other technical
experts from the field have been invited to join
the standardisation work.