无水氨基酸类离子液体-聚乙二醇混合溶剂吸收CO2的动力学

摘要

The non-aqueous mixed solvent system based on amino acid ionic liquids(AAILs)and polyethylene glycol 400(PEG400)shows many advantages,such as extremely low vapor pressure,good thermal stability,low viscosity and regeneration energy,high CO2 capacity and selectivity,which is suitable for the pre-combustion process facing high absorption temperature and pressure conditions.The CO2 absorption rates for three kinds of AAILs with tetrabutylphosphonium ([P4444]+) as cation,glycine(Gly),alanine(Ala),proline(Pro)as anions in PEG400 were determined by pressure drop method,and then the relevant absorption kinetic model was developed.The absorption rate were ranked as [P4444][Gly]-PEG400 > [P4444][Pro]-PEG400 > [P4444][Ala]-PEG400 at 333.15K and [P4444][Pro]-PEG400 > [P4444][Gly]-PEG400 > [P4444][Ala]-PEG400 at 373.15K.According to the absorption kinetic results,the CO2 absorption by AAIL-PEG400 system was fast reaction.Based on the absorption model,the key kinetic parameters were obtained,providing the basic data and principle of design for the coming industrial development and process design.%以聚乙二醇400(PEG400)为溶剂,氨基酸类离子液体(AAILs)作为化学吸收剂的混合体系具有蒸汽压极低、热稳定性好、黏度和再生能耗低、CO2吸收量和选择性高等优点,适用于燃烧前CO2捕集过程的高温高压吸收条件.本文采用压降法,测定了以四正丁基膦([P4444]+)为阳离子,甘氨酸(Gly)、丙氨酸(Ala)和脯氨酸(Pro)作为阴离子的3种氨基酸类离子液体的混合溶剂体系对CO2的吸收速率,并建立了该无水体系的CO2吸收动力学模型.对于反应速率而言,在333.15K时,[P4444][Gly]-PEG400>[P4444][Pro]-PEG400>[P4444][Ala]-PEG400,温度升高至373.15K时,[P4444][Pro]-PEG400>[P4444][Gly]-PEG400>[P4444][Ala]-PEG400;根据相关吸收动力学参数,推测出CO2在AAILs-PEG400中的反应均为快反应.通过研究其吸收动力学,获得了关键的吸收动力学数据,为后续的工业开发设计提供基础数据和设计依据.