煤层气转化制合成气的催化剂研究

A study of catalysts for coalbed methane gas converted into synthetic gas

煤层气转化制合成气工艺的生产成本低、能耗小,对减轻全球性温室效应具有一定的作用,是煤层气利用的较好方案,但该反应存在催化剂积炭严重易失活等问题。为此,采用Ni/MgO—Al2O3催化剂,在常压固定床反应器上进行了CO2重整CH4制合成气反应的研究,系统地考察了载体制备方法、MgO含量、焙烧方式等因素对催化剂性质的影响,并采用N2物理吸附和XRD检测手段对催化剂进行了表征。结果表明,采用共沉淀方法制备催化剂载体,当MgO含量为4%,在550℃流动空气环境里焙烧4h后所得到的催化剂10%Ni/4%MgO—Al2O3用于煤层气转化制合成气的反应,CH4和CO2的转化率分别可达到82%和92%,且反应6h内转化率没有降低,催化剂未发生积炭现象,其催化活性和稳定性都较好。

The technology of coalbed methane gas being converted into synthetic gas has become one of the most preferable ways for coalbed methane utilization because of its low cost in production,low energy consumption,and role in reducing the global greenhouse effect.However,the performance of catalysts used in this technology will be badly influenced by serious carbon deposition and easy deactivation.Therefore,the study on the CH4-CO2 reforming reaction to produce synthetic gas was carried out over a Ni/MgO-Al2O3 catalyst in a fixed-bed reactor.An investigation was made into many factors,which have effect on the performance of catalysts,including the preparation methods of catalytic carriers,MgO content,calcination methods,etc.The characteristics of catalysts were analyzed by adopting N2 physical adsorption and X-ray diffraction (XRD).The results showed that ①10%Ni/4%MgO-Al2O3,which was prepared by co-precipitation and calculated at 550℃ in flowing air for 4 h,shows a better performance in coalbed methane gas converted into synthetic gas,②the conversion rate of CH4 and CO2 is 82% and 92% respectively,without any reduction within 6 h,and ③this catalyst maintains its good performance without carbon deposition but with good activity and stability.