基于富液分流改进工艺的混合胺法燃煤电厂烟气碳捕集过程模拟研究

Simulation and Analysis of Carbon Dioxide Capture Process with Split Flow Modification Using MDEA/PZ Blend Solution in a Coal-fired Power Plant

[目的]工艺流程优化是降低燃煤电厂烟气胺化学吸收法碳捕集过程能耗的重要方法。[方法]通过Aspen plus软件模拟研究了MEA吸收剂和混合胺MDEA/PZ吸收剂在三种不同富液分流改进工艺下的烟气二氧化碳捕集性能,分析了贫液负荷和分流比对二氧化碳再生过程热负荷和冷负荷的影响,同时通过浓度驱动力和温度驱动力分析揭示了解吸过程特性。[结果]研究结果表明,三种富液分流工艺均能有效降低二氧化碳再生热负荷和冷负荷,其中方案3效果最为显著,因为该方案可获得更为均衡更低的驱动力分布,有效减少了不可逆损失。[结论]相比常规MEA碳捕集系统,结合了MDEA/PZ吸收剂和富液分流改进工艺方案3的碳捕集系统再生热负荷和冷负荷可降低35.36%和71.42%,具有较好的应用前景。

[Introduction]Flow sheet modification is an important method to reduce the high energy cost in carbon dioxide capture process by amine chemical absorption in coal-fired power plant.[Method]The performances of MEA and MDEA/PZ solution in three carbon dioxide capture processes with split flow modifications were simulated by Aspen plus soft.The effects of lean load and split ratio on CO2 regeneration heat duty and cold duty were analyzed,and stripping process property was revealed by analysis of concentration and temperature driving force.[Result]It showed that all the three split flow modifications can effectively reduce the heat and cold duty.The modification case 3 presented the best performance because this modification led to better distribution of driving force,reducing the irreversible loss significantly.[Conclusion]Compared to convention MEA process,MDEA/PZ process with the case 3 modification reduced the heat and cold duty by 35.36% and 71.42%,showing good potential in industrial application.