【作者】 胡贤辉；

【导师】 王兴军；

【作者基本信息】 华东理工大学 ， 热能工程， 2011， 硕士

【摘要】 本文采用金属镍作为甲烷化反应催化剂的活性中心,对多种改进的催化剂进行了研究。通过考察不同载体制备的催化剂性能,优选出了MgO-Al2O3复合载体。实验得出最优NiO负载量为15%；微量的La203、Ce02能改善催化剂的稳定性、抗积碳和抗烧结的性能。实验发现沉淀剂的种类对制备镍基催化剂的理化性质和反应性能具有显著影响。通过XRD、H2-TPR、BET、TPD、TPO等方法对不同沉淀剂的催化剂进行表征,结果表明：采用尿素沉淀剂,颗粒的比表面达到223.55m2·g-1,具有较稳定的催化活性；氨水沉淀制备的催化剂颗粒粒径小,与载体结合力强,但稳定性不如碳酸铵沉淀。这主要是沉淀剂影响了催化剂活性组分晶相的形成、表面镍的分散程度和对H2的吸附能力。添加第二活性组分后,催化剂的性能会发生变化。添加助剂Cu会减小Ni的粒径,提高分散度,Ni-Cu之间的协同作用会减少高温下活性组分的流失。添加助剂Mn会降低催化剂的还原温度,这是由于Mn在还原过程中发生价态变化,并通过电子效应影响NiO的性能,在300～400℃时Ni-Mn催化剂活性明显高于Ni催化剂。更多还原

【Abstract】 In this work high performance methanation catalysts were prepared with Ni as an activity center. Compared with kinds of carriers on the performance of methanation, MgO improved Al2O3 was chose as the carrier, the optimum nickel loading of the catalyst is about 15%. Additional La2O3、CeO2 in a trace of amount could improve the properties of stability, reduce carbon deposition and prevent from sintering.Different kinds of precipitants have a great impact on the catalysts’performance of methanation. The characterization of the catalysts were determined by XRD、H2-TPR、BET、TPO、TPD. Based on the results, the surface areas of the catalysts by urea preparation reached up to 223.55 m2·g-1, which suggested an stabilized catalytic activity; the catalyst prepared by ammonia precipitant possessed smaller partial diameter, combined more stable with carrier, but the stability for methane was lower than by ammonium carbonate precipitant. It was indicated that the precipitants mainly affected the crystal-phase formation process of the catalyst active component, the dispersion of active Ni on the catalyst surface and hydrogen adsorption capacity.The properties of catalyst changed while adding another metal components. Adding Cu will lead to the decrease of crystal mean particle size and the increase of distribution. Ni-Cu interaction could reduce the loss of active components especially at high temperature. The promoter Mn can reduce the reduction temperature. The activity is obviously higher than Ni-based catalysts at 300-400℃due to the electron effect resulted from the different oxidation-reduction potential of Mn.更多还原