K_2CO_3/AC常温下脱除密闭空间CO_2反应机理  

Reaction mechanism of dry potassium-based solid sorbent for CO_2 capture in confined spaces at ambient temperature

作　　者：郭亚飞[1] 赵传文[1] 黎昌海[1] 陆守香[1] 

机构地区：[1]中国科技大学火灾科学国家重点实验室,安徽合肥230027

出　　处：《舰船科学技术》2014年第8期80-86,共7页Ship Science and Technology

基　　金：国家自然科学基金资助项目(51206155);中国博士后科学基金资助项目(2011M501061;2012T50579)

摘　　要：密闭空间CO2脱除是环境控制和生命保障系统的重要任务,研究适用于密闭空间高活性可再生CO2清除剂至关重要。本文利用热重分析系统对钾基负载型吸收剂K2CO3/AC(AC为活性炭)进行实验。在20℃,1%CO2和2%H2O基准工况下,对比吸收剂和载体AC的反应特性,探索K2CO3/AC常温下脱除密闭空间CO2反应机理,并探究温度、CO2浓度和H2O浓度等反应条件对脱碳特性影响。结果表明:载体AC对H2O和CO2脱除机制为物理吸附作用;K2CO3/AC主要依靠活性组分K2CO3与二者的化学反应,在H2O气氛中通过水合反应迅速转化为K2CO3·1.5H2O,在CO2/H2O气氛中通过碳酸化反应生成KHCO3,表现出优越的反应活性。K2CO3/AC的碳酸化反应性能随着温度升高而减弱,随着CO2浓度和H2O浓度增加而增强。该研究结果确定了K2CO3/AC常温下脱除低浓度CO2反应机理,为常温下密闭空间CO2脱除技术提供了理论基础。TheremovalofCO2fromconfinedspacestomaintainitsconcentrationatanacceptable level is emerging as a significant task in environmental control and life support system. It is crucial to develop a renewable sorbent with high activity for CO2 capture in confined spaces. A novel potassium-based sorbent of K2 CO3/AC （ AC： activated carbon ） was synthesized via impregnation method. The reaction mechanism and CO2 capture characteristics of the sorbent at ambient temperature were investigated with thermo-gravimetric apparatus （ TGA） . The results showed that weak adsorption capacity of the support of AC on CO2 and H2 O was attributed to the physisorption of its porous structure, while chemisorption was responsible for the CO2 capture process of K2 CO3/AC. It was confirmed that the sorbent exhibited superior capture capacity by converting K2 CO3 into K2 CO3 ·1. 5H2 O in H2 O and KHCO3 in CO2/H2 O with rapid chemical reactions, which were so-called hydration and carbonation. The CO2 capture performance of K2 CO3/AC increased with the increase of CO2 and H2 O concentrations but decreased with the increase of temperature. The results obtained in this study determined the mechanism of K2 CO3/AC for capturing CO2 of low concentration at ambient temperature, which would effectively provide statistical support for CO2 removal from confined spaces.

关 键 词：K2CO3 AC 密闭空间 CO2脱除 反应机理 

分 类 号：TQ424[化学工程]