关键词: 低阶煤, 煤热解, 煤拔头, 混合发电系统

Abstract: Low rank coal account for 80% of coal resources in China. Coal pyrolysis will result in liquid tar, pyrolysis gas and solid char products. Liquid tar could be used to obtain chemicals or fuel oil, pyrolysis gas could be used as fuel or production of methane, char could be used as clean solid fuel. Continuous research and development on Chinese low rank coal pyrolysis fundamentals, process and equipment scale-up were carried out in the Institute of Process Engineering, Chinese Academy of Sciences. Laboratory scale coal fast pyrolysis experiments between 500? 850℃ showed that, the production of pyrolysis gas was increasing with the increase of temperature, while the production of liquid tar reached the maximum value at the temperature of 650℃. The ignition temperature of char increased with the increase of pyrolysis temperature. The combustion rate of char decreasd with the increase of pyrolysis temperature, but much higher than that of anthracite. A 10 t/d capacity coal pyrolysis/combustion pilot plant was build up in Langfang campus. Experimental results of Erodes sub-bituminous coal showed that, when the char was burned as fuel, the co-production of liquid tar was 6.6% and 2.5% of dried coal, pyrolysis gas was 10.3% and 18.8% of dried coal at pyrolysis temperatures 640 and 760℃ respectively. The IPE-Power, a pyrolysis bridged hybrid power system was proposed for low rank coal poly generation for coal power plant. The technical and economic analysis showed that, the IPE power system was technical and economical feasible for new power plant for coproduction of liquid tar and power. Retrofitting of 300 MW subcritical coal power plant with this technology was also discussed, the results indicate that for the retrofitted power plant the net coal consumption was decreased from 355 g/(kW?h) to 303 g/(kW?h).

Key words: low rank coal, coal pyrolysis, coal topping, hybrid power system