Abstract: Effect of steam and CO₂ concentration in atmosphere at both calcination and carbonation stages on CO₂ capture for calcium-based sorbent was investigated in a twin-bed calcination/carbonation cycle reaction system.Microstructure analysis from electronic scan image and N₂ adsorption/desorption was supplemented to understand mechanism affecting carbonation by steam.The results show that steam in atmosphere of both calcination and carbonation stages can enhance CO₂ capture performance of sorbents, and the optimal mass percent in these atmospheres is 10% and 5%, respectively.Effect of steam at carbonation stage on CO₂ capture was stronger for sorbent modified by alumina cement than for natural limestone.High CO₂ partial pressure at calcination stage results in severe sintering, thus low capacity of CO₂ capture.Increase of CO₂ capture performance can be achieved by using steam in the atmosphere of both calcination and carbonation stages because steam in flue gas can improve micro-porosity of these sorbents.

Key words: steam, calcium-based sorbent, carbonation

摘要： 在循环煅烧/碳酸化反应系统上考察煅烧气氛和碳酸化气氛中水蒸气含量以及CO₂分压对钙基吸收剂成型颗粒碳酸化的影响,通过对钙基吸收剂微观结构分析(扫描电镜、氮吸附分析)以理解水蒸气影响碳酸化特性的机理。结果表明,煅烧气氛和碳酸化气氛中的水蒸气均可提高钙基吸收剂的碳酸化转化率,水蒸气含量分别为10%和5%时,吸收剂的碳酸化性能较好;水蒸气在碳酸化气氛中对高铝水泥改性吸收剂的改善作用较石灰石显著。煅烧气氛中的CO₂分压越高,烧结现象越严重,降低钙基吸收剂的捕集效率;碳酸化气氛CO₂分压提高,有利于提高钙基吸收剂的碳酸化转化率。烟气中水蒸气丰富了吸收剂的微观孔隙,使得吸收剂捕集CO₂性能得到改善。

关键词: 水蒸气, 钙基吸收剂, 碳酸化