低阶煤热解多联产与混合发电系统

Low rank coal pyrolysis poly-generation and hybrid power system

中国煤资源中80%以上属于中高挥发分的低阶煤.将煤炭进行热解分级,液体产物可转化为化学品和燃料油,气体产物可作为燃气或转化为天然气使用,固体半焦是洁净的固体燃料.中国科学院过程工程研究所自1999年开始对煤热解分级高效利用技术的基础理论、工艺和设备放大等方面进行了系统研究,并在廊坊中试基地建立了煤处理量为10t/d的煤热解燃烧中试平台.采用该实验装置对多种低阶煤进行热解,结果表明,在燃用半焦的同时焦油产率为煤干重的6%-10%,热解煤气产率为煤干重的8%-12%.介绍了过程所煤热解分级混合发电系统,并对该系统在燃煤发电厂的应用进行了技术经济分析.

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）.