【摘要】 采用流化床反应器并以水蒸气作为气化-流化介质,研究了以NiO为载氧体在800～960℃内的煤化学链燃烧反应特性。实验结果表明,载氧体与煤气化产物在反应器温度高于900℃体现了高的反应活性。随着流化床反应器温度的提高,气体产物中CO2的体积浓度(干基)呈单调递增;CO、H2、CH4的体积浓度(干基)呈单调递减;煤中碳转化为CO2的比率逐渐递增,碳的残余率逐渐递减。反应器出口气体CO2、CO、H2、CH4的生成率随反应时间呈单峰特性,H2生成率的峰值远小于CO的峰值;且随反应器温度升高,CO2生成率升高,CO、H2、CH4的生成率降低。反应温度高于900℃时,流化床反应器NiO载氧体煤化学链燃烧在9min之内就基本完成,CO2含量高于92%。更多还原

【Abstract】 Chemical looping combustion(CLC) is a novel combustion technology with inherent separation of the greenhouse gas CO2.The feasibility of using NiO as an oxygen carrier during chemical looping combustion of coal was investigated at 800—960℃.The experiment used a laboratory fluidized bed as the reactor,where steam acted as the gasification-fluidization medium.The reaction between oxygen carrier and solid fuel occurred via the gasification intermediates,primarily CO,H2 and CH4.The oxygen carrier particles exhibited high reactivity above 900℃.The flue gas component variation as a function of reactor temperature and reaction time was discussed,respectively.With increasing CO2 generation rate as the result of increased reactor temperature,C residual rate decreased correspondingly.At 800—960℃,CO2 concentration(dry basis) in flue gas presented a monotone increasing curve,and CO,H2 and CH4 concentrations(dry basis) decreased monotonously.The variation of CO2,CO,H2 and CH4 generation rates in exhaust gas as a function of reaction time presented a parabolic curve,respectively.Moreover,the peak value of H2 generation rate was less than the value of CO.With an increase in reactor temperature,CO2 generation rate increased remarkably,while CO,H2 and CH4 generation rates decreased rapidly.The reaction between oxygen carrier and solid fuel,or overall coal gasification was accomplished in nine minutes above 900℃,and CO2 concentration was greater than 92%.更多还原