膜吸收法脱除电厂模拟烟气中的CO_2

Removal of CO_2 from Simulated Flue Gas of Power Plants by Membrane-Based Gas Absorption Processes

以氨基乙酸钾、一乙醇胺和甲基二乙醇胺水溶液为吸收液,研究了聚丙烯膜接触器分离模拟烟气中CO2的技术.分析了气液流速、吸收剂浓度、烟气CO2浓度和吸收液CO2负荷等对传质速率和脱除率的影响.结果表明:1mol·L-1MEA在流速0·1m·s-1,烟气流速0·211m·s-1时,CO2传质速率高达7·1mol·(m2·s)-1;1mol·L-1氨基乙酸钾在流速0·05m·s-1,烟气流速0·211m·s-1时,脱除率为93·2%;4mol·L-1氨基乙酸钾在同样条件下脱除率达98%;而且在试验的较广烟气CO2浓度范围内,氨基乙酸钾CO2脱除率保持在90%以上.试验证明膜吸收法既适合目前最为普遍的PF和NGCC烟道气脱除CO2,也是一种应用广泛、有良好发展前景的CO2分离法.

Three typical absorbents such as aqueous of aminoacetic acid potassium(AAAP),monoethanolamine(MEA) and methyldiethanolamine(MDEA) are selected to investigate the performance of CO_2 separation from flue gas via membrane contactors made of hydrophobic hollow fiber polypropylene porous membrane. Impacts of absorbents, concentrations and flow rates of feeding gas and absorbent solution, cyclic loading of CO_2 on the removal rate and the mass transfer velocity of CO_2 are discussed. The results demonstrate that the mass transfer velocity was 7.1 mol·(m^2·s)~ -1 for 1 mol·L~ -1 MEA with flow rate of 0.1 m·s~ -1 and flue gas with that of 0.211 m·s~ -1. For 1 mol·L~ -1 AAAP with flow rate of 0.05 m·s~ -1 and flue gas of 0.211 m·s~ -1, CO_2 removal rate (η)was 93.2% and η was 98% for 4 mol·L~ -1 AAAP under the same conditions. AAAP being absorbent,η was higher than 90% in a wider range of concentrations of CO_2. It indicates that membrane-based absorption process is a widely-applied and promising way of CO_2 removal from flue gas of power plants, which not only appropriates for CO_2 removal of flue gas of widely-used PF and NGCC, but also for that of flue gas of IGCC can be utilized widely in future.