Abstract:

The capture of CO₂ from flue gas is commonly achieved using chemical absorption processes. The process requires optimization to enhance CO₂ removal efficiency while minimizing energy consumption. This paper used Aspen Plus simulation to model both the typical amine-based CO₂ capture process and an optimized low-energy, high-efficiency CO₂ capture process. The effects of MEA + H₂O and MEA + MDEA + H₂O absorbent circulation and absorption temperature on CO₂ removal rate and energy consumption of lean solution regeneration were investigated. The results revealed that both the typical amine-based process and the low-energy, high-efficiency process met the design requirements of capturing CO₂ with a purity of ≥90% and a removal efficiency of >90%, while keeping energy consumption below 3.0GJ/tCO₂. The optimal solvent circulation rates were 60m³/h for MEA+H₂O and 65m³/h for MEA+MDEA+H₂O. The absorption temperature range was 40—45℃. Under the same absorption agent and circulation rate, both processes achieved similar CO₂ removal rates and recovery efficiencies. The low-energy, high-efficiency CO₂ capture process reduced the energy consumption for lean liquid regeneration by 0.13GJ/tCO₂. After the optimization of CO₂ capture process, equipment investment and utility consumption costs could be significantly reduced.

Key words: low-concentration CO₂ flue gas, CO? removal, lean liquid regeneration heat consumption, CO₂ removal efficiency, process simulation

摘要：

燃气烟气中CO₂捕集一般采用化学吸收工艺，该工艺需要优化实现CO₂脱除率提高、能耗降低。本文使用Aspen Plus模拟了典型醇胺法CO₂捕集和优化的低能耗高效CO₂捕集过程，考察了两种工艺下乙醇胺（MEA）+H₂O和MEA+甲基二乙醇胺（MDEA）+H₂O不同吸收剂循环量、吸收温度对CO₂脱除率和贫液再生能耗的影响，分析了最优工艺技术条件，两种工艺的设备及公用工程运行成本。研究结果表明，典型醇胺法CO₂捕集工艺和低能耗高效CO₂捕集工艺都可以达到捕集后CO₂纯度≥90%（体积分数）、CO₂脱除率>90%、能耗<3.0GJ/tCO₂的设计要求，MEA+H₂O吸收剂的最优循环量是60m³/h，MEA+MDEA+H₂O吸收剂的最优循环量是65m³/h，吸收温度是40~45℃。相同吸收剂及循环量下，两种工艺的CO₂脱除率和CO₂回收率基本相同，低能耗高效CO₂捕集工艺贫液再生能耗可降低0.13GJ/tCO₂。CO₂捕集工艺经过优化后，设备投资及公用工程运行成本可以明显降低。

关键词: 低浓度CO₂烟气, 脱碳, 贫液再生能耗, CO₂脱除率, 工艺模拟