Environmental Impact of Black Liquor Gasification

Environmental impact of black liquor gasification (BLG) is discussed. Biofuels from a BLG process excel in terms of well-to-wheel carbon dioxide emission reduction and energy efficiency. Forest biorefinery utilizing gasification (in a black liquor gasification combined cycle (BLGCC) configuration) rather than a Tomlinson boiler is predicted to produce significantly fewer pollutant emissions due to the intrinsic characteristics of the BLGCC technology. Syngas cleanup conditioning removes a considerable amount of contaminants and gas turbine combustion is more efficient and complete than boiler combustion. Also, there could be reductions in pollutant emissions and hazardous wastes resulting from cleaner production of chemicals and fuels that are now manufactured using fossil energy resources. Production of power, fuels, chemicals, and other products from biomass resources creates a net zero generation of carbon dioxide as plants are renewable carbon sinks. BLG whether conducted at high or low temperatures is still superior to the current recovery boiler combustion technology. Implementation of IGCC power plants will cause net savings in cooling water requirements and net reductions in wastewater discharges. The most significant environmental impact caused by BLG will occur in air emissions. The overall reduction of Total reduced sulphur (TRS) gases using gasification technology will also reduce odor, which will improve public acceptance of pulp and paper mills, particularly in populated areas.