煤电机组应对二氧化碳减排的策略

Strategies of CO_2 Emission Reduction for Coal-fired Units

美国环保署要求,新建燃煤电厂的CO_2排放限值为年平均发电碳排放强度不大于635 kg/MWh。其建议的"减排最佳系统"(BSER)技术路线为:对部分烟气量进行碳捕捉、运输和储存(CCS)。由于CCS存在成本、安全性和地质储存条件苛刻等短板,可采用非CCS的煤电机组碳减排策略,即进一步提高超超临界机组的热效率、采用冷热电联供、燃煤耦合生物质发电等3种技术路线。对这些技术路线满足美国碳排放限值的技术现状、前景和条件进行分析后,得出了当前的技术水平下采用冷热电联供或燃煤耦合生物质发电是两个可行且经济的手段,而进一步提高超超临界机组的热效率也具有现实可行性的结论。

The standard promulgated by U. S. Environmental Protection Agency specifies the CO2 emission rate of less than 1 400 lb/MWh（635 kg/MWh） for newly constructed coal-fired units and one of the roadmaps for cutting down the pulverized coal（PC） unit CO2 emission recommended by EPA is post-combustion partial carbon capture and storage（CCS）. Due to obvious disadvantage of CCS in terms of cost,safety and geologic restrict,strategies for PC unit,including thermal efficiency increasing,CHP CCHP and biomass co-firing,are proposed to satisfy the CO2 emission cap without CCS. The present status,outlook as well as the boundary condition for performance of such technologies are discussed. It is concluded that the CHP CCHP and biomass co-firing is both technically and economically feasible nowadays and the higher efficiency advanced ultra-supercritical（AUSC） technology is expected in the near future.