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Title:
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R&D in support of tar measurement standardisation
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Author(s):
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Published by:
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Publication date:
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ECN
Biomass, Coal and Environmental Research
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1-9-2006
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ECN report number:
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Document type:
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ECN-C--06-046
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ECN publication
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Number of pages:
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Full text:
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168
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Download PDF
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Abstract:
This summary describes the CEN accredited and approved Tar Measurement Standard which has been developed in this SenterNovem project in combination with a European project during the last years. The final voting was executed until February 2006 and the Tar Measurement Standard (TMS) was fully approved by the CEN representativies (25 countries) and no against votes were given. The development of the Tar Measurement Standard dates back from the late 1990’s and focussed on the Standardisation at both a national and European level (CEN) of the measurement of organic contaminants (called ‘tar’).
The procedures are designed to cover the tar measurements for different air or oxygen blown gasifier types (updraft or downdraft/fixed bed or fluidised bed gasifiers), operating conditions (0 - 900°C and 0.6 - 60 bars), and tar concentration ranges from 1 mg/mn3 to 300 g/mn3. Although several institutes have sometimes used this Guideline, it did not have the status of an international standard yet. The overall objective of the projects was therefore to remove this obstacle by standardising and optimising the Guideline. The development and standardisation of the TMS was via extensive in-house tests at ECN and Round Robin tests and Parallel Measurement Campaigns of more than 7 specialised laboratories in Europe. The measurement principle is based on the discontinuous sampling of a gas stream containing particles and condensable organic compounds. The sampling train is shown schematically in Figure 1.
The TMS method extensively covers the determination of a broad range of organic compounds which can occur in biomass-producer gas. The TMS is capable of determining organic compounds that can generally be named ‘tar’. Low temperature tar, that is formed in the updraft gasifier and consists mainly of polar compounds whereas high temperature tars from downdraft and fluidised bed gasifiers mainly contain non-polar compounds. The tar compounds are divided into two different groups - the gravimetric tar and a number of individual organic compounds (GC-detectable tars). These tars are in detail described in the CEN TMS descriptions.
The parallel measurement campaigns have collected information on the accuracy and reproducibility of the sampling method and the analysis techniques.The measurement campaigns were carried out at the commercial scale updraft gasifier of Harboøre (Denmark) and at Umsicht in Germany at a CFB gasifier. The results indicated a good reproducibility of the Guideline as illustrated in Figures 2 - 3. In the second measurement campaign at Umsicht 6 institutes participated (Umsicht, ECN, BTG, VTT, TU Graz, DTI).
With the aid of this TMS the performance of different types of gasifiers and subsequent gas cleaning train and engine or turbine generator can be monitored in a technically accepted manner and will allow manufacturers and legislative organisations to have a reliable determination of tar emissions.
The Technical Standard is available at the national standardisation institute. Information is also available at the websites www.tarweb.net and www.gasnet.uk.net.
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