Investigation On Catalysts Of Synthetic Gas Production By Reforming Of Natural Gas

Natural gas is one of the three major fossil fuels in the world, and much attention hasbeen focused on its application. The usage of natural gas can be divided into direct andindirect methods. Combustion is one method for direct use, which is usually used as fuels tosupply heat. The indirect method is to convert natural gas to synthetic gas （H₂+CO）,followed by the synthesis of chemical products. The indirect use of natural gas can reduceenergy waste and environmental pollution problems as well as provide high valued products.In this paper, the catalyst for reforming of methane with CO₂-O₂to produce synthetic gaswas studied. The effect of preparation of composite carrier （Al₂O₃-MgO）（includingpreparation methods, calcinations temperature, calcinations temperature, calcinationsenvironment and MgO content） was first discussed. Then the active components, Ni, wasloaded on the composite carrier by impregnation method, and then modified with Ce. Theeffect of Ni loadings and Ce loadings was discussed. Finally, reaction conditions, such asreaction temperature, space velocity were explored. The supports and catalysts werecharacterized by N2physical adsorption and X-ray diffraction （XRD）.The results show that the suitable catalyst for the combined reforming of methane withCO₂-O₂is12%Ni-3%Ce/Al₂O₃^-15%MgO catalyst prepared by impregnating Ni and Ce on thecomposite carrier （Al₂O₃-MgO）, which was prepared by co-precipitation and calcinated at600℃in flowing air. The optimized reaction conditions were determined to be reactiontemperature of750℃, space velocityof19000h^-1, and raw material volume ratio ofCH₄:CO₂:O₂of1:1:0.6. The conversion of at87%for CH₄and94%for CO₂were obtained.Characterization of the catalysts by XRD showed that the formation of CeNi₅alloy in thecatalyst when Ce was added played important role in the catalytic performance. It is worthnoticing in the exploration of the catalyst system for this reaction.