亚临界机组碳捕集系统优化及其对热力系统影响的模拟研究

Simulation Study on the Optimization of Carbon Capture System and Its Impact on Thermal System in Subcritical Coal-fired Power Plants

为降低醇胺法碳捕集系统对燃煤电厂热经济性的影响,通过ASPENPLUS软件搭建了基于速率模型的碳捕集系统,并构建了集成富液分流工艺、贫液闪蒸压缩工艺与蒸汽过热度利用的新型碳捕集系统。结果表明新型碳捕集系统在富液分流比为0.1、闪蒸压力为0.16MPa时,再生能耗最低,为3.09GJ/tCO_(2),相比常规碳捕集系统降低了20.77%,其中,蒸汽过热度的利用使得再生能耗降低了11.54%。此外,利用EBSILON软件搭建了耦合碳捕集系统的亚临界机组热力系统,研究得到当机组负荷为127.55MW、CO_(2)捕集量为50万吨/年时,新型碳捕集机组的锅炉热负荷相比常规碳捕集机组降低了1.87%,发电煤耗降低了7.22g/kWh。可见,采取的优化措施不仅可以降低碳捕集系统的再生能耗,还大幅度改善了亚临界碳捕集机组的热经济性。

In order to reduce the infuence of alcohol-amine carbon capture system on thermal economy of coal-fired power plants,a carbon capture system was built based on rate model through ASPEN PLUS software,and built a novel carbon capture system integrating rich liquid split process,lean vapor compression process and steam superheat utilization.The results show that when the liquid-rich split ratio is 0.1 and the flash tank pressure is 0.16 MPa,the energy consumption of the novel carbon capture system is the lowest(3.09 GJ/t(CO_(2))),which is 20.77%lower than that of the conventional carbon capture system.Among them,the utilization of steam superheat reduces the energy consumption of the system by 11.54%.In addition,EBSILON software was used to build the sub-critical unit thermal system coupled with the carbon capture system.The results showed that when the unit load is 127.55 MW and CO_(2) capture capacity is 500000 tons/year,the boiler heat load of the novel carbon capture unit decreased by 1.87%and the coal consumption for power generation decreased by 7.22 g/kWh.It can be seen that the optimization measures adopted in this study can not only reduce the reboiler duty of the carbon capture system,but also greatly improve the thermal economy of the subcritical carbon capture unit.