【作者】 郭军；

【导师】 石川；

【作者基本信息】 大连理工大学 ， 物理化学， 2010， 硕士

【摘要】 甲烷与二氧化碳重整制取低碳氢比(CO／H2比为1)的合成气,为费托合成提供理想的原料。同时CO2是重整反应的反应物,这不但在一定程度上减少了温室气体的排放,而且能够将CO2作为一种可以利用的碳源。因此该反应对于节约资源和发展低碳循环经济都具有重要的意义,同时还能缓解日益严重的环境问题。虽然甲烷与二氧化碳重整具有环境和经济上的诸多优势,但重整反应始终没有工业化,其主要原因为贵金属成本高和镍基催化剂积碳问题严重。本文以金属碳化钼以及镍改性碳化钼为催化剂,对其甲烷与二氧化碳重整反应进行研究,研究工作主要有如下三方面：1.采用程序升温碳化方法以MoO3为前躯体碳化制备Mo2C,采用XRD对其进行表征分析,考察碳化温度、Mo2C／Al2O3、以及等离子体放电对Mo2C催化剂催化CH4-CO2重整反应活性以及稳定性的影响。结果表明常压下高温低空速有利于Mo2C的稳定,等离子体放电对其活性影响很小,催化剂活性失活主要原因是Mo2C氧化失活而不是积碳。2.采用共沉淀的方法制备NiMoOx前躯体,并采用程序升温法碳化制备Ni-Mo2C,考察镍的加入对碳化物碳化温度的影响。同时考察了不同Ni／Mo比,空速、不同合成温度对催化活性的影响,以及常压高温条件下Ni-Mo2C催化剂的稳定性。结果表明在常压下Ni-Mo2C催化剂具有较高的稳定性,在实验的36小时内活性相对稳定,CH4转化率达到85%以上。3.用程序升温还原(CH4-TPR)和程序升温氧化(CO2-TPO)等技术对催化剂的微观反应机制进行研究,结果表明：镍的加入有利于碳化物的合成,同时促进甲烷裂解,从而有利于碳化物在常压条件下的氧化-碳化循环的建立。更多还原

【Abstract】 The synthesis gas with a low hydrocarbon ration produced by the reforming of methane with carbon dioxide provides an ideal raw material for Fischer-Tropsch synthesis. While CO2 being a reactant, this not only reduce greenhouse gas emissions to some extent, but also make CO2 as an available carbon source. So this reforming reaction is significant on resource conservation and the development of low-carbon economy when easing the increasingly serious environmental problems. Although the reforming has many environmental and economic advantages, this still has not been industrialized, which mainly due to the high cost of precious metals and the serious problem of nickel-based catalysts coking. In this paper, metal molybdenum carbide and nickel modified molybdenum carbide catalyst were prepared and their catalytic performances were investigated for CH4-CO2 reforming reaction in laboratory scale. The main content was described from three aspects as follows:1. Mo2C was prepared from the precursor MoO3 by temperature programmed carbonization method and characterized by XRD analysis. Carbonization temperature, Mo2C/Al2O3, and the impact from plasma discharge on activity and stability of CH4-CO2 reforming reaction with Mo2C being the catalyst were also studied. The results show that low-speed and high temperature at atmospheric pressure are conducive to Mo2C stability, and plasma discharge has little effect on its activity. The main reason of catalyst deactivation is Mo2C oxidation inactivation rather than coke.2. NiMoOx and Ni-Mo2C were prepared by co-precipitation and temperature programmed carbonization method respectively. The effect of added nickel on carburized temperature of the carbide was studied. We also investigated the impact of different Ni/Mo ratio, GHSV, synthesis temperature on the catalytic activity and stability of Ni-Mo2C catalyst at atmospheric pressure and high temperature. The results show that under atmospheric pressure Ni-Mo2C catalyst has high stability, and within the experimental 36 hours the activity is relatively stable, the conversion rate of CH4 can reach to 85%.3. The reaction mechanism was studied by temperature programmed reduction (CH4-TPR) and temperature programmed oxidation (CO2-TPO). The results show that the addition of nickel is facilitated for carbide synthesis and promoting methane decomposition, therefore it is conducive to the stability of molybdenum carbide at atmospheric pressure.更多还原