Performance of tar removal by absorption and adsorption for biomass gasification

Biomass gasification is an attractive and successful waste-to-energy technology. Even though it has been performing effectively, many troubles are still occurring. For advanced applications, gas needs to be clean enough and tar should extensively be removed. Otherwise, tar in the producer gas will condense at reduced temperature and will cause blocking and fouling of engines. Physical tar removal is proven to be technically and economically attractive approach for gas cleaning. In this paper, three tar removal techniques were investigated for each type of tar; 1) heavy tar removal by absorption using vegetable oil and waste-cooking oil scrubbers, 2) light tar removal by adsorption using rice husk and rice husk char adsorbent bed and 3) heavy tar removal by combination of absorption and adsorption using vegetable oil scrubber and rice husk char adsorbent bed. Temperature of the thermal tar decomposition process was set at 800 °C and temperature of the physical gas cleaning unit ccwas at room temperature. The result showed that the absorption technique was effective for heavy tar removal and the adsorption technique was capable of light tar removal. By combining vegetable oil scrubber and rice husk char adsorbent bed, 95.4% of gravimetric tar could be successfully removed.