Effect of CaO hydration and carbonation on the hydrogen production from sorption enhanced water gas shift reaction
Effect of CaO hydration and carbonation on the hydrogen production from sorption enhanced water gas shift reaction
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DOI：
10.1016/j.ijhydene.2012.04.160
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发表时间：
2012-08
影响因子：
7.2
通讯作者：
Zhenshanl Li;Yang Liu;N. Cai
中科院分区：
文献类型：
--
作者：
Zhenshanl Li;Yang Liu;N. Cai
基于钙环的吸附增强水煤气变换反应（SEWGS）是一种新兴的制氢和CO2捕集技术。SEWGS主要包括两个反应，即催化WGS反应和CaO与CO2的本体碳酸化反应，固体产物为CaCO3，Ca（OH）2可能由CaO与H2O在水蒸汽存在下在气相中反应生成。在流化床反应器中研究了Ca（OH）2和CaCO3对催化水煤气合成反应和碳酸化反应的影响。结果表明，在400 °C下，水合吸附剂和CaCO3对WGS反应没有催化活性。当温度升高到500 °C和600 °C时，水合吸附剂的催化活性得到部分恢复，但这取决于气相中的水蒸气分数，Ca（OH）2脱水后新鲜CaO表面的恢复可能是催化活性恢复的原因。CaCO3在高温（>600 °C）下对WGS反应具有催化作用，这可能是由于CaCO3的分解和再碳酸化过程中CaO的瞬时生成。并对可能的机理进行了讨论。
Sorption enhanced water gas shift reaction (SEWGS) based on calcium looping is an emerging technology for hydrogen production and CO2capture. SEWGS involves mainly two reactions, the catalytic WGS reaction and the bulk carbonation of CaO with CO2, and the solid product is CaCO3, and the Ca(OH)2may be formed from the reaction of CaO with H2O with the presence of steam in gas phase. The effect of Ca(OH)2and CaCO3on the catalytic WGS reaction and carbonation reaction was studied in a fluidized bed reactor. It was found that the hydrated sorbent and CaCO3did not show any catalytic reactivity toward WGS reaction at 400 °C. When the temperature was increased to 500 °C and 600 °C, the catalytic reactivity of hydrated sorbent was recovered partially, but this will depend on the steam fraction in gas phase, the recovery of fresh CaO surface from dehydration of Ca(OH)2may be the reason of catalytic reactivity recovery. CaCO3can catalyze the WGS reaction at the high-temperature (>600 °C), this may due to the CaCO3decomposition and recarbonation processes in which the CaO is transiently formed. The possible mechanism was discussed.