ERK6-1999-20002 Development of a standard method (protocol) for the measurement of organic contaminants "tars" in biomass producer gases

Contacts
Website: www.tarweb.net
Summary Information



To find similar Items, click on a keyword below:
EESD (Energy, Environment and Sustainable Development) : Electricity : Thermochemical Conversion

Proposal No:	ENK5-2002-00623
Date Prepared:	February 2004
Source:	European Bio-Energy Projects (EUR 20808)

Introduction

Gasification technologies are expected to play a key role in expanding the use of biomass. The gas can be used, for example, for co-firing in coalfired power plants, electricity generation in standalone conversion devices (gas engines, gas turbines, fuel cells), and the production of gaseous/liquid fuels or chemicals.

Proper measurement of contaminant levels in biomass gasification-based systems is crucial to their optimisation and implementation. The measurement of organic contaminants or "tars" in syngas still causes much confusion. Measurement methods, as well as definitions for tars in biomass gasification-based systems, are numerous and non-consistent. As a result, the comparison of data and the definition of clear maximum allowable concentrations for tars are problematic.

Since tars are considered as the major problem causing contaminants, this generates a large obstacle for the market introduction of these systems.

The objective of the project was to remove this obstacle by developing a standard measurement method (Guideline) which is accepted and used by parties working on biomass gasification and can form the basis for a subsequent standardisation procedure at CEN.

Activities

The work consisted of three main activities:

• development, optimisation and testing of the Guideline,
• dissemination and internalisation of the Guideline and
• the initiation of the standardisation of the Guideline on a European level.

In the first activity, a draft version of the Guideline was prepared. The Guideline was then optimised and tested by means of a reviewing round and through R&D activities performed outside, but coordinated from inside this project. In the second activity the Guideline was disseminated by means of an Internet site (www.tarweb.net), by using Internet mailing lists/discussion groups and by means of papers and presentations at three European Biomass conferences in Tirol, Sevilla and Amsterdam. In the third activity a task force was installed at CEN to start the standardisation procedure of the Guideline.

Results

The main result of this project is a guideline for the sampling and analysis of tars and particles in biomass gasification producer gases. The measurement principle of the Guideline is based on discontinuous sampling and it is set-up in such a way that particles can also be measured quantitatively. The tar and particle sampling system consists of a heated probe, a heated particle filter, a condenser and a series of impinger bottles containing isopropanol to dissolve the tars. The solvent containing bottles are placed in a warm (bottles 1-4) and a cold bath (bottles 5 and 6) so that the sampled gas is cooled in two steps, first to 20°C and finally to -20°.

The postsampling involves Soxhlet extraction of the tars on the particle filter and the collection of all tars in one bulk solution. Finally, the analysis comprises the determination of the gravimetric tar mass from the bulk solution and the determination of the concentration of individual tar compounds. The Guideline has also achieved the following results:

• It can be used for both raw and clean producer gases of all commonly applied biomass gasifiers
• It has been disseminated to, and gained acceptance among, major European and North American parties that develop, commercialise and advise on biomass gasification technology
• It has entered the procedure to become a European standard.

The full version of the Guideline can be downloaded from the website.

Impact and exploitation

In the first place, the Guideline will allow companies, institutions and universities that develop gasification technology to compare tar concentrations. Secondly, it will allow manufacturers of gasifiers, gas cleaning systems and engine or turbine generator sets to convince potential end users of the technical performance of the sub-systems, and to define tolerances from which guarantees on performance, system lifetime etc. can be derived. These guarantees decrease the non-technical risks of implementation of biomass gasification based systems.

The Guideline will be transformed into a CEN Standard to widen its international acceptance and application. To this purpose, CEN Task Force 143 "Measurement of Organic Contaminants (tars) in Biomass Producer Gases" has been set up.