Study On Nickel-Based Catalysis For Methane Reforming With Carbon Dioxide To Produce Syngas

The catalytic reforming of methane and carbon dioxide to produce syngas has important environmental and economic benefits.In recent years it has attracted widely attention. The key issue for the application of this process is the development of catalysts with good activity and high stability. Precious metals were not suitable for industrial production in the research and development due to its limited resources and expensive price.So numerous researches focused on non-precious metal catalysts, particularly developing of Ni-based catalysts in reforming of methane.The main contents of this paper is to prepare nickel-based catalysts with good catalytic performance and superior anti-coking properties. Explore in the catalytic reforming of methane and carbon dioxide through active ingredient and support modification and adding promoters.This paper first prepared Mg-Al-LDHs by co-precipitation,and load active component Ni on it to get Ni/Mg-Al-LDO catalysts by impregnation.The catalysts were characterized by means of XRD、BET、TPR,Ni supported on the Mg-Al-LDHs in the form of NiO and NiAl2O4.Ni-based catalyst has a specific surface area decreases with the increase of the loading of Ni.10%Ni/Mg-Al-LDO catalyst has two reduction temperatures were395℃and800℃.The effects of Ni/Mg-Al-LDO catalysts in catalytic reforming of methane and carbon dioxide that500℃is the most appropriate calcination temperature.10%Ni/Mg-Al-LDO catalyst under the conditions of:n(CH4):n(CO2)=1:1,V(CH4)=15ml/min,GHSV=36000ml·gcat-1·h-1, p=0.1MPa, T=700℃exhibit good catalytic activity.CO2and CH4conversion was respectively84.5%and82.1%, H2and CO selectivity reached80.9%and89.0%, H2/CO value was0.90, the amount of catalyst coke reached26.38%.Secondly, prepared Ni/Mg-Al-LDO catalysts modified with Co and characterized by means of XRD、BET、TPR.Co were well dispersed on the catalysts surface.Because of adding Co reduced grain size of Ni.When the doping amount of Co was6%, the catalyst surface area reached242.3m2/g.The effects of Ni/Mg-Al-LDO catalysts modified with Co in catalytic reforming of methane and carbon dioxide,the doping amount of Co was6%of the catalyst,CO2and CH4conversion was respectively93.9%and87.4%, H2and CO selectivity reached90.4%and96.2%, H2/CO value was0.93, the amount of catalyst coke reached17.62%.Thirdly,discussed Ni/Mg-Al-LDO catalysts modified with CeO2,adding promoter CeO2could increase the surface area of catalyst. When the doping amount of CeO2was8%the catalyst surface area reached265.8m2/g.CeO2added could reduce the reduction temperature of10%Ni/Mg-Al-LDO catalyst. The effects of Ni/Mg-Al-LDO catalysts modified with CeO2in catalytic reforming of methane and carbon dioxide,the doping amount of CeO2was8%of the catalyst,CO2and CH4conversion was respectively95.6%and92.0%, H2and CO selectivity reached94.2%and98.1%, H2/CO value was0.97, the amount of catalyst coke reached12.29%.Fourth, prepared carrier Mg-Al-LDHs modified with K to get K/MgAlO then to prepare Ni-K/MgAlO catalysts.The catalysts were characterized by many means,K were well dispersed on the catalysts surface.And adding K could increase the surface area of catalysts.The catalyst with doping amount of K was8%has two reduction temperatures were395℃and800℃.And in catalytic reforming of methane and carbon dioxide CO2and CH4conversion was respectively94.6%and93.2%, H2and CO selectivity reached94.6%and98.5%, H2/CO value was0.96.