Ni/γ-Al_(2)O_(3)/Monolith催化剂的制备及其甲烷自热重整性能

Preparation of Ni/γ-Al_(2)O_(3)/Monolith catalyst and its capability for methane autothermal reforming

以陶瓷堇青石为载体、拟薄水铝石为涂层,采用分步涂覆法制备了Ni/γ-Al_(2)O_(3)/Monolith催化剂,利用N2吸附-脱附,H_(2)-TPR,XRD,SEM等方法对催化剂进行表征,研究了催化剂焙烧温度、Ni负载量及气时空速对催化剂催化甲烷自热重整活性的影响,并考察了催化剂的稳定性。实验结果表明,经酸处理后的堇青石比表面积从0.3 m^(2)/g增大到145.1 m^(2)/g,孔体积增大到原来的35倍;负载γ-Al_(2)O_(3)涂层后,孔体积继续增大,使更多的活性组分均匀负载到堇青石上。在焙烧温度为600℃条件下,Ni负载量为20%(w)的催化剂催化效果最佳;在反应温度750℃下能够承受50000 h^(-1)的气时空速,甲烷转化率达99%以上,且具有较好的稳定性。

Ni/γ-Al_(2)O_(3)/Monolith catalyst was prepared by multistep coating method using ceramic cordierite as support and pseudo-boehmite as coating and characterized by N2 adsorption-desorption,H_(2)-TPR,XRD and SEM.The effects of calcination temperature,Ni loading and GHSV on the activity of the catalyst for methane autothermal reforming were studied.The stability of the catalyst was also investigated.The experimental results show that the specific surface area of acid-treated cordierite increases from 0.3 m^(2)/g to 145.1 m^(2)/g,and its pore volume increases to 35 times.The pore volume continues to increase afterγ-Al_(2)O_(3) coating,so that more active components are uniformly loaded on cordierite.Under the conditions of calcination temperature 600℃ and Ni loading 20%(w),the catalyst has the best catalytic effect.The catalyst can withstand 50000 h^(-1) of GHSV at 750℃ with more than 99%of methane conversion and good stability.