REFINEMENT OF PRODUCER GAS GENERATED FROM BIOMASS GASIFIER

摘要

Producer gas (PG) generated from biomass by thermo-chemical gasification process has been proved to be areliable and renewable substitute for petroleum fuels to drive internal combustion engines. The gasificationtechnology has been developed well and also commercialised. However, more technological advancementsmust happen in the refining of PG. Generally, the refinement is confined to the removal of tar and particulatesfrom PG before supplying it to the engines. This paper proposes to remove additionally carbon dioxide andwater vapour from PG so that its heating value can be increased and faster combustion can be attained in theengine cylinder. In this direction, the various CO2 removal technologies which are currently employed forcombustion flue gas, natural gas and biogas have been first studied in detail. They are: physical absorption insolvents, chemical absorption by reagents, adsorption, membrane separation and refrigeration. In the presentresearch, a batch of experiments has been conducted by washing PG with water to absorb CO2 physically and ina separate batch of experiments PG has been treated with aqueous ammonia to absorb CO2 chemically. For bothexperiments, the PG was generated by a downdraft biomass gasifier fed with wood pieces. The CO2 reductionobtained was 10.9% in physical absorption by water and 95% in chemical absorption by aqueous ammonia.Along with the reduction of CO2 and H2O from PG, the tar and particulates content of PG could also be reducedby absorption method.