基于分级气化的燃烧前CO_(2)捕集发电系统及性能分析  

Performance Analysis of a Power Generation System with Pre-combustion CO_(2) Capture Based on Staged Coal Gasification

作　　者：李济超 韩巍[2,3] 马文静 叶旖茵[2,3] 金红光 LI Jichao;HAN Wei;MA Wenjing;YE Yiyin;JIN Hongguang(School of Energy,Power and Mechanical Engineering,North China Electric Power University,Beijing 102206,China;Institute of Engineering Thermophysics,Chinese Academy of Sciences,Beijing 100190,China;University of Chinese Academy of Sciences,Beijing 100190,China)

机构地区：[1]华北电力大学能源动力与机械工程学院,北京102206 [2]中国科学院工程热物理研究所,北京100190 [3]中国科学院大学,北京100190

出　　处：《动力工程学报》2024年第8期1253-1263,1297,共12页Journal of Chinese Society of Power Engineering

基　　金：国家科技重大专项资助项目(J2019-I-0009-0009)。

摘　　要：为实现煤炭高效低碳化发电,提出了一种基于分级气化和化学回热的燃烧前CO_(2)捕集发电系统。该系统将煤气化过程解耦为600℃的热解过程和1400℃的气化过程,利用燃气轮机的排烟余热来驱动热解过程,此外利用合成气的显热驱动热解气重整。将新系统与参比系统进行热力学性能比较,分析了不同关键参数对新系统性能的影响。结果表明:在90%碳捕集率下,新系统的净发电效率、效率和度电CO_(2)排放量分别为39.97%、38.94%和85.27 g/(kW·h),相较于参考系统,分别提高了2.33个百分点、2.34个百分点和降低了5.27 g/(kW·h);新系统性能提升的主要原因在于其气化过程的不可逆损失大幅减少,为参比系统的62.13%;当气化温度为1200℃、水碳比为1.4、碳捕集率为80%时,系统净发电效率最高,可达41.3%;随着碳捕集率的增加,净发电效率及度电CO_(2)排放量均降低,其中度电CO_(2)排放量最低可达51.1 g/(kW·h)。A power generation system with pre-combustion CO_(2) capture based on staged coal gasification and chemical recuperation was proposed to achieve high-efficiency and low-carbon power generation from coal.The system decoupled the coal gasification process into two stages:a pyrolysis stage at 600℃ and a gasification stage producing syngas at 1400℃.The exhaust heat from gas turbines was used to drive pyrolysis,and in addition,the sensible heat of syngas was used to drive pyrolysis gas reforming.The thermodynamic performance of the present system was compared with the reference system,and the effect of different key parameters on the system performance was analyzed.Results show that at the carbon capture ratio of 90%,the net power generation efficiency,exergy efficiency and CO_(2) emissions per kW·h of the present system are 39.97%,38.94%and 85.27 g/(kW·h),respectively,which are 2.33%,2.34%higher and 5.27 g/(kW·h)lower than the reference system.The superior performance of the present system comes mainly from the significant reduction in the irreversible losses of its gasification process,which is 62.13% of the reference system.The analysis further indicates that the system net power generation efficiency reaches an optimal 41.3% under the steam-to-carbon ratio of 1.4 and the carbon capture ratio of 80%at the gasification temperature of 1200℃.As the carbon capture ratio increases,the net power generation efficiency and CO_(2) emissions per kW·h both decrease,the latter with a minimum of 51.1 g/(kW·h).

关 键 词：二氧化碳捕集 煤气化 [火用]效率 净发电效率 化学回热 

分 类 号：TK16[动力工程及工程热物理—热能工程]