超临界二氧化碳布雷顿/有机朗肯循环联合系统的热力学特性  

Thermodynamic Properties of Supercritical CO2 Brayton/Organic Rankine Cycle Combined System

作　　者：曹宇 王治红[1] 马宁[2] 李良均[2] CAO Yu;WANG Zhi-hong;MA Ning;LI Liang-jun(Chemistry and Chemical Engineering,Southwest Petroleum University,Chengdu,China,610500;Sichuan Kehong Petroleum and Natural Gas Engineering Co.Ltd.,Chengdu,China,610213)

机构地区：[1]西南石油大学化学化工学院,四川成都610500 [2]四川科宏石油天然气工程有限公司,四川成都610213

出　　处：《热能动力工程》2020年第4期9-15,23,共8页Journal of Engineering for Thermal Energy and Power

摘　　要：针对再压缩式超临界二氧化碳布雷顿发电循环(S-CO2),将有机朗肯循环(ORC)作为底循环用于回收系统余热,建立了S-CO2/ORC联合循环。采用Aspen Plus建立分析模型,根据顶循环余热温度范围和安全环保要求,选取R245fa作为ORC系统工质,分析透平进口温度、透平进口压力及分流比对循环效率的影响,并通过分析耗能设备的功率变化找到影响系统效率变化的因素。结果表明:通过顶循环低温余热的回收利用,系统热效率提高4%以上;增大透平进口温度可提高顶循环的热效率,但对底循环热效率的影响较小;随着顶循环透平进口压力的增大,顶循环热效率增加而底循环热效率下降;在透平入口温度680℃、入口压力280 MPa的条件下,存在最优的再压缩循环分流比0.66使得联合循环热效率最高;使用ORC底循环回收顶循环余热,最高可以将系统热效率从50.3%提高到53.7%,联合系统可以获得6.7%的效率提升。For the recompressed supercritical carbon dioxide Brayton power generation cycle(S-CO2/ORC),in this paper the Organic Rankine Cycle(ORC) is added as the bottom cycle to recover the residual heat.The S-CO2/ORC combined cycle is established,and Aspen Plus is used to establish the simulation model.According to the top cycle residual heat temperature range and the environmental protection requirements,R245 fa is selected as the ORC system working fluid.Turbine inlet temperature,turbine inlet pressure and the effect of split ratio on cycle efficiency are analyzed.By studying the changes in power of major equipment,the mechanism of these influences are explained.The results show that the thermal efficiency of the system can be increased at least by 4% through recycling the low temperature waste heat of the top cycle.An increase in turbine inlet temperature will increase the thermal efficiency of the top cycle and have less effect on the bottom cycle efficiency,while an excessive turbine inlet pressure can increase top cycle efficiency but reduce bottom cycle efficiency.When the top cycle turbine inlet temperature is selected to be 680 ℃,the inlet pressure is 280 MPa,the cycle split ratio is 0.66,the system thermal efficiency can be increased from 50.3% to 53.7% under these conditions,and the combined cycle efficiency can be increased by up to 6.7%.

关 键 词：超临界二氧化碳 布雷顿循环 有机朗肯循环 余热回收 热效率 

分 类 号：TK221[动力工程及工程热物理—动力机械及工程]