"Tar Guideline" measurement method

The Tar measurement Guideline gives a set of procedures for the measurement of organic contaminants and particles in syngas from biomass gasifiers. Biomass gasifiers can be updraft-fixed-bed gasifiers, downdraft-fixed-bed gasifiers or fluidised-bed gasifiers, operating under atmospheric or pressurised conditions. The Guideline is aimed to measure organic contaminants and particles in the concentration range typically from 1 mg/m_n³ to 300 g/m_n³ at all relevant conditions (0 - 900°C and 0.6 - 60 bar).

The measurement principle of the Guideline is based on discontinuous sampling and it is set-up in such a way that also particles can 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°C. The sampling train is shown schematically in Figure 1. The post-sampling 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 by gas chromatography.

Further details on the Guideline can be found here.