基于压缩式热泵的CO_(2)-MDEA/PZ碳捕集工艺优化

Compression heat pump in CO_(2)-MDEA/PZ system for post combustion carbon dioxide capture

当前化学法CO_(2)捕集系统的高投资、高吸收液再生能耗和高运行费用成为限制其大规模应用的主要障碍。为了回收解吸塔塔顶蒸汽中的潜热与显热,促进解吸反应的进行,利用Aspen plus软件建立基于压缩式热泵技术的有机胺法捕集CO_(2)流程模拟模型,主要探究了解吸塔塔底压力、进解吸塔富液温度、有机工质气化率以及工艺流程对CO_(2)再生过程的影响。结果表明:有机工质R123制热系数较R141b和R245fa高,其性能系数(COP)高达2.35,而排气温度较R141b和R245fa更低。压缩式热泵采用R123为循环工艺介质,热泵回收的热量用于加热贫富液换热器后的热富液以降低吸收液再生能耗。综合考虑解吸系统的再生能耗、工质循环量和解吸效果,通过12级位置注入15%的富液比合适。热泵回收余热工艺的投资回收期为0.82 a,具有较高的经济价值。

The high investment,high energy consumption for absorbent regeneration,and high operational costs of current chemicalbased CO_(2)capture systems pose major obstacles to their large-scale application.To recover the latent and sensible heat in the steam at the top of the stripper and facilitate the desorption reaction,a process simulation model for CO_(2)capture using organic amines based on compression heat pump technology was established using Aspen plus software.This primarily explored the impact of stripper bottom pressure,rich solvent temperature entering the stripper organic working fluid vaporization rate,and process flow on the CO_(2)regeneration process.The results demonstrate that the heating coefficient of the organic working fluid R123 is higher than that of R141b and R245fa.Specifically,its coefficient of performance(COP)reaches as high as 2.35,while its exhaust temperature is lower compared to R141b and R245fa.Additionally,the exhaust temperature of R123 is lower compared to that of R141b and R245fa.The compression-type heat pump employs R123 as the circulating process medium,and the heat recovered by the heat pump is utilized to heat the post-heat-exchange rich solution in the lean/rich solution heat exchanger,thereby reducing the energy consumption for the regeneration of the absorbent solution.Considering the regeneration energy consumption of the desorption system,working fluid circulation volume,and desorption efficiency,injecting a 15%rich solvent ratio at the 12th stage position is deemed appropriate.The payback period for the heat recovery process using the heat pump is 0.82 years,demonstrating significant economic value.