Electric Power Technology and Environmental Protection

【目的】燃煤电厂目前是中国最主要的工业排放源。为减少燃煤电厂CO₂排放，助力双碳目标的实现，比较CO2的化学吸收工艺优缺点十分必要。【方法】本文在梳理燃煤电厂碳捕集技术的基础上，从吸收剂优化、工艺流程优化及脱碳单元与燃煤电站集成系统优化三个方面展开分析，重点探讨了混合胺吸收剂、两相吸收剂、分相少水吸收剂等新型吸收剂的性能，并总结了吸收塔级间冷却、富液分流、闪蒸压缩等工艺流程的节能效果。同时，结合技术经济性指标，对蒸汽引射器、汽轮机、吸收式热泵等集成系统的经济性进行了评估。【结果】研究表明，降低再沸器热负荷可以通过改良吸收剂及优化脱碳单元工艺流程两种方法实现；混合胺吸收剂的研发潜力最大，其CO₂再生能耗较传统乙醇胺（monoethanolamine，MEA）吸收剂要低27.7%。混合吸收剂能够避免单一吸收剂高吸收率与低再生能耗相互冲突的制约，制备简便，工程实际应用广泛；两相吸收剂、匀相少水吸收剂、深共晶吸收剂等吸收剂均能不同程度地降低再生能耗，提高脱碳性能，但存在黏度大不利于转移的问题；不同脱碳工艺流程组合会相互影响，基于节能机理分析的工艺流程高效组合是实现节能优化的前提。集成系统优化的核心是余热余压利用，利用形式包括对外做功、回收低品位余热及集成新的热量来源，其中再沸器疏水循环及热泵集成技术最为成熟。【结论】未来燃煤电厂化学吸收法碳捕集要实现大规模商业化应用并获益，需综合考虑发电成本、减排成本等技术经济指标，兼顾捕集系统的节能性、简洁性、经济性。

[Objective] In order to reduce CO_(2) emissions from coal-fired power plants and help achieve the dual-carbon goal, it is necessary to compare the advantages and disadvantages of the chemical absorption process of CO_(2). [Methods] Based on the optimization technology of carbon capture in coal-fired power plants, this paper analyzed from three aspects, absorbent optimization, process flow optimization and integrated system optimization of decarbonization unit and coal-fired power plants. The performance of new absorbents such as mixed amine absorbent, two-phase absorbent and phase-separated water-less absorbent was discussed, and the energy-saving effects of process flows such as inter-stage cooling of absorption tower, rich liquid split and flash compression were summarized. At the same time, combined with the technical and economic indicators, the economy of integrated systems such as steam ejectors, steam turbines, and absorption heat pumps was evaluated. [Results] The research shows that reducing the heat load of the reboiler can be achieved by improving the absorbent and optimizing the process flow of the decarburization unit. The mixed amine absorbent has the greatest development potential, and its CO_(2) regeneration energy consumption is 27.7% lower than that of traditional monoethanolamine (MEA) absorbent. The mixed absorbent can avoid the conflict between the high absorption rate and low regeneration energy consumption of a single absorbent. It is easy to prepare and widely used in engineering practice. Two-phase absorbent, homogeneous water-less absorbent, deep eutectic absorbent and other absorbents can reduce the regeneration energy consumption and improve the decarburization performance to varying degrees, but there is a problem of high viscosity, which is not conducive to transfer. The combination of different decarburization process will affect each other. The efficient combination of process based on the analysis of energy saving mechanism is the premise of energy saving optimization. The core of integration system optimizition is the utilization of waste heat and pressure to achieve energy cascade utilization. The utilization forms include external work, recovery of low-grade waste heat and integration of new heat sources. The reboiler hydrophobic cycle and heat pump integration technology are the most mature among them. [Conclusion] In order to achieve large-scale commercial application and benefit from chemical absorption carbon capture in coal-fired power plants in the future, it is necessary to comprehensively consider the technical and economic indicators such as power generation cost and emission reduction cost, and take into account the energy saving, simplicity and economy of the capture system.