Co-gasification of torrefied wood biomass and sewage sludge

摘要

Torrefied biomass and municipal sewage sludge are renewable resources that can be used instead of coal within entrained flow slagging gasifiers. Simulations regarding the gasification of those resources and further production of methanol were performed using Aspen Plus software. This study presents a techno-economic comparison between three cases: gasification of torrefied biomass, a mixture of torrefied biomass and sewage sludge, and coal. Two different methodologies were used regarding the CO2 taxation calculation. The first methodology considered zero CO2 tax for two processes that use renewable resources, and the second methodology considered negative CO2 tax, because renewable carbon is bound into a product. The result showed that the combination of torrefied biomass and sewage sludge could be a good alternative to coal. If negative CO2 tax were considered, a process using torrefied biomass or a combination of torrefied biomass and sewage sludge would highly outperform the coal only process in terms of net present value after 30 years.