蒸汽活化水泥支撑钙基吸收剂活性及强度特性

doi:10.11949/j.issn.0438-1157.20161389

摘要/Abstract

摘要：

拟通过蒸汽活化实现多次循环后机械成型、水泥支撑钙基吸收剂的活性再生，在鼓泡床上研究了活化前后活性，在颗粒碰撞装置上研究活化前后强度及过热处理的影响，并分析了微观结构。结果表明，失活水泥支撑颗粒活化后活性提升幅度大，950℃煅烧下活化后钙转化率由0.113升至0.419，石灰石仅由0.089增至0.278。碰撞实验显示活化后成型颗粒强度下降明显。石灰石活化后出现大量裂缝，可增加活性和削弱强度；而成型颗粒活化后未出现裂缝，但其孔隙提升更佳且表面松散，活性提升显著，强度下降也明显。对活化后颗粒进行过热处理明显改善了强度，由于其可消除晶格内空穴及缺陷。对失活水泥支撑颗粒蒸汽活化并过热处理可同时提升活性并改善强度。

关键词: 钙基吸收剂, 水泥支撑, 钙循环, 蒸汽活化, 机械强度, CO₂捕集

Abstract:

Steam hydration was planned to reactivate the spent synthetic cement-supported Ca-sorbents pelletized by mechanical granulator which possessed excellent performance. The effect of steam hydration on the reactivity of sorbents was investigated in a bubbling fluidized reactor. A specially designed impact apparatus was employed to evaluate the strength of reactivated pellets. The transitions of microstructure after hydration were also analyzed. The results showed that the reactivity of synthetic pellets was elevated significantly by steam hydration. The conversion of CaO for pellets increased from 0.113 to 0.419 after hydration in comparison with the raw limestone from 0.089 to 0.278, while the mechanical strength of synthetic pellets declined severely after reactivation. Large cracks emerged on hydrated limestone, which increased the reactivity and impaired the strength. Similar appearance was not observed on hydrated synthetic pellets, except improved porosity and expended surface which could enhance CO₂ capacity and decline the strength. Superheating allowed the annealing of stacking faults and mechanical strain formed by hydration was proven to be able to improve the strength of hydrated pellets. Thus, the technology combining steam hydration with superheating can reactivate the spent synthetic sorbents without obvious strength decay.

Key words: calcium sorbent, cement support, calcium looping, steam hydration, mechanic strength, CO₂ capture

中图分类号:

TK09

余志健, 段伦博, 苏成林, 赵长遂. 蒸汽活化水泥支撑钙基吸收剂活性及强度特性[J]. 化工学报, 2017, 68(4): 1637-1645.

YU Zhijian, DUAN Lunbo, SU Chenglin, ZHAO Changsui. Reactivity and strength of cement-supported calcium sorbent reactivated by steam for CO₂ capture[J]. CIESC Journal, 2017, 68(4): 1637-1645.

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