AN EXPERIMENTAL STUDY ON BIOMASS COAL BRIQUETTING PROCESS

摘要

The Biomass Coal briquette is an effective practical method to control air pollution caused by coal combustion, as well as to reduce GHG emissions through substitution of fossil fuel with biomass. The objective of this research is to establish a new briquetting technology to simplify the briquetting process and reduce energy consumption, by utilizing the linkage function of biomass fiber. Effects of coal type, briquetting pressure, biomass shape and content, and the water content in raw material on briqutting performance were examined initially at an industrial pilot scale. Results show that briquetting pressure to fix the linkage of biomass fiber is no more than 120 MPa, and a higher pressure causes a negative effect. The reasonable lower limit of biomass content is about 15%. Biomass drying in the air for a certain period (water content is generally less than 12%) is suitable for briquetting using the new mechanism. With a coal water content of 6-9% (depending on coal type), increasing the biomass proportion and decreasing briquetting pressure to a certain degree could significantly offset the negative effect of water content on high-pressure briquetting. Mechanical performance improves with higher biomass proportion and lower water content in the raw material. Because of the advantages of the new briquetting method, the process line can be simplified dramatically. The power consumption is about 15kWh per ton briquette. Total processing cost is about RMB20 (equivalent to US$2.5) per ton briquette, including capital investment and operation cost, less than 1/3-1/5 of that in conventional ones.