天然铁矿石为氧载体的生物质化学链气化制合成气实验研究

Synthesis gas generation by chemical-looping gasification of biomass using natural hematite as oxygen carrier

在一个小型鼓泡流化床反应器上以Ar气为流化介质,对以天然铁矿石为氧载体的生物质化学链气化制合成气过程进行了研究。考察了反应温度对合成气组分、气体产率、碳转化率以及气化效率的影响,反应时间对合成气组分的影响;探讨了氧载体存在对生物质气化过程的影响。结果表明,天然铁矿石可以作为生物质化学链气化制合成气反应过程的氧载体,代替富氧空气或高温水蒸气作为生物质气化的气化剂;随着温度的升高,产物气体中CO、H2的浓度逐渐增加,CO2、CH4浓度缓慢降低;随着反应时间的延长,合成气中H2、CO、CH4的相对浓度缓慢增加,而CO2相对浓度逐渐降低;氧载体的存在能显著提高气体产率和碳的转化率及气化效率。扫描电镜-能谱(SEM-EDS)分析表明,当超过850℃时,铁矿石氧载体颗粒表面烧结现象明显,但反应前后,颗粒表面的成分及含量基本保持不变。

The chemical looping gasification（CLG） of biomass with natural hematite（Fe2O3） as oxygen carrier was experimentally investigated in a bubbling fluidized bed reactor using argon as fluidizing gas.The effects of reaction temperature,resistance time,and the presence of oxygen carrier on the syngas composition,gas yield,carbon conversion,and gasification efficiency were examined.The experimental results show that the natural hematite can be used as oxygen carrier in CLG of biomass.The concentration of CO and H2 increases slightly,while that of CO2 and CH4 declines slightly with the increasing of temperature during biomass gasification.In addition,the concentration of H2,CO,and CH4 in the syngas slowly increases with the reaction time,but CO2 concentration shows an opposite trend.The presence of oxygen carrier can significantly increase the gas yield and carbon conversion.The analysis by Scanning electron microscopy-Energy Disperse Spectroscopy（SEM-EDS） shows that the iron ore oxygen carrier is obviously sintered when the reaction temperature is greater than 850 ℃.However,the composition of element on the particle surface changes little during the reaction.