Use of two different adsorbents for sampling tar in gas obtained from peat gasification

Gasification is one of the most promising techniques proposed for the production of energy from biomass. Gasification for producing synthesis gas is regarded as one of the most reasonable options for utilising biomass. Gasification of biomass produces a raw gas mixture containing tar, among other components. Traditional methods for tar sampling are based on cold solvent-trapping coupled with solvent absorption in impingers. The present work focusses on a solid-phase adsorption method for determining the concentration of tar compounds. A modified sampling device consisting of 500 mg of amino-phase sorbent and 100 mg of activated coconut charcoal was chosen as optimal for sampling tar (including its volatile organic compounds) in synthesis gas produced by biomass gasification. For research in a real life context, the circulating fluidised bed (CFB) gasifier situated in eastern Latvia (Rezekne region) was used. Varying volumes of product gas were drawn through the adsorbents, and the total amount of tar was then compared to the number of its individual component compounds. With an increase of the volume of product gas drawn through the adsorbents, a persistently larger amount of benzene and toluene passes through the amino-phase adsorbent and is collected on the activated coconut charcoal. An increased volume of the product gas leads to a growing number of compounds detected and identified on the amino-phase adsorbent.