LNG冷能用于富氧燃烧联合循环发电系统  

Application of LNG Cold Energy in Combined Cycle Power Generation System with Oxy-fuel Combustion

作　　者：梁莹 管延文[1] 蔡磊[1] 刘文斌[1] 韩逸骁 向艳蕾 LIANG Ying;GUAN Yahweh;CAI Lei;LIU Wenbin;HAN Yixiao;XIANG Yanlei

机构地区：[1]华中科技大学环境科学与工程学院,湖北武汉430074

出　　处：《煤气与热力》2018年第8期14-21,共8页Gas & Heat

摘　　要：为使天然气电厂实现低成本碳捕获,构建一套集空气分离、富氧燃烧、联合循环发电以及碳捕获的集成系统。将LNG冷能先后用于空气分离和碳捕获环节,降低系统能耗。将富氧燃烧技术应用于燃气-蒸汽联合循环发电系统,在发电的同时实现低成本碳捕获。采用Aspen plus流程模拟软件,通过敏感度分析对系统工况进行优化。在联合循环发电系统中,采用CO_2循环中和燃烧温度,并且随着CO_2循环量的增加,燃气轮机出口温度降低,燃气轮机输出功率增加;燃气轮机出口温度降低,会导致蒸汽循环中过热蒸汽温度降低,蒸汽轮机的输出功率减小。LNG冷能的应用可以极大地降低碳捕获能耗,对碳捕获压力进行讨论,当碳捕获压力为0.7 MPa时,可以保证CO_2液化温度不低于三相点温度,并且使CO_2压缩功耗最小。经过敏感度分析,最终确定系统的最佳工况点:当CO_2循环量为8.4 kmol/s,蒸汽循环的循环压力为12 MPa,循环蒸汽量为6.7kmol/s时,联合循环碳捕获系统总发电功率达417.4 MW,热效率为47.0%,火用效率为42.2%。In order to achieve low-cost carbon capture in natural gas power plants,an integrated system of air separation,oxy-fuel combustion,combined cycle power generation and carbon capture is built.LNG cold energy is used for air separation and carbon capture to reduce the system energy consumption. The oxy-fuel combustion technology is applied to the gassteam combined cycle power generation system to achieve low-cost carbon capture while generating electricity. Aspen plus procedure simulation software is used,and the system conditions are optimized by sensitivity analysis. In the combined cycle power generation system,the CO2 cycle is used to neutralize the combustion temperature. With the increase of the CO2 cycle rate,the gas turbine outlet temperature decreases and the gas turbine output power increases. The lowering of the gas turbine outlet temperature will lead to the decrease of the superheated steam temperature in the steam cycle and the decrease of the steam turbine output power. LNG cold energy can greatly reduce the carbon capture energy consumption. The carbon capture pressure is discussed. When the carbon capture pressure is 0. 7 MPa,it can ensure that the CO2 liquefaction temperature is not lower than the three-phase point temperature and minimize the CO2 compression power consumption. After sensitivity analysis,the optimal operating point of the system is finally determined：When the CO2 cycle rate is 8. 4 kmol/s,the steam cycle pressure is 12 MPa,and the circulating steam volume is 6. 7 kmol/s,the total generated power of combined cycle carbon capture system is 417. 4 MW,the thermal efficiency is 47. 0% and the exergy efficiency is 42. 2%.

关 键 词：LNG冷能 空气分离 富氧燃烧 联合循环发电 碳捕获 

分 类 号：TM611[电气工程—电力系统及自动化]