The Preparation And Application Of High Activity Carbon Dioxide Reforming Of Coke Oven Gas Catalyst

CO₂ is the world's rich resources of carbon.Each year about 30 billion tons of carbon dioxide emit in the atmosphere all over the world,only about 100 million tons are used,so utilization is very low.At present,the greenhouse effect is a serious threat to human survival of the earth's environment.Therefore,the CO₂ conversion is an important and urgent work,but also which is the researchhotspot in the field of international resource and ecology.Coke oven gas is the by-product from coke plants during the production of blast furnace coke.Besides eich in H2,this product gas also contains large amount of higher hydrotocarbons like methane.A large number of coke oven gas is letted out,which not only waste the resourse but also pollute the envirronment.CO₂ reforming of coke oven gas to syngas can make full use of the greenhouse gases of CO₂ and CH4.The syngas is a basic chemical raw material gas,and ultimately the products involve in the field of chemicals,synthetic materials,paints,pesticides,dyes,pharmaceuticals and so on,exhibiting broad application prospects and very high economic value.On the basis of investigation about the thermodynamics and diffusion process of CO₂ reforming of coke oven gas,applying the research group self-developed's non-catalytic/catalytic two-stage process.Firstly,adopting three different catalyst preparation processes:sintering-impregnating-drying-baking,impregnating-drying-roasting-sintering,impregnating-sintering,using a-Al₂O₃ as carrier,the effect of three different preparation methods on XCH4?XCO₂?Y?CO+H2?and H2/CO was observed and studied.The results show that the impregnating-drying-roasting-sintering prepared fresh catalyst are not observed in the diffraction peaks of NiO,at the same time reduced state after the reaction NiAl2O4peak disappearing by XRD.It appears well catalytic propertiese then other two catalysts,for example,the conversion rate of CH4 and CO₂ are higher at the same temperature,H2/CO in a very small fluctuation range between 2.16 to 2.51.This ratio is suitable for follow-up of industrial processes and has important industrial value to methanol synthesis,Fischer-Tropsch synthesis.Catalyst particle size was investigated on the basis of this preparation method.In the experiment,all catalysts are cylindrical particle.Though comparing diameter of 2mm with 3mm catalyst particle,catalytic properties of the former is superior to the latter.Secondly,in order to change a-Al₂O₃'s performance,two ways are adopted.On one hand,sodium carboxymethyl cellulose?CMC?,cellulose?MCC?as pore-forming agents,and kaolin as binder were added them to a-Al₂O₃ powders,which could increase catalyst's specific surface area and pore size.On one other hand,alkaline earth metals of Ca and Mg additives were putted in the a-Al₂O₃ powders,which could neutralize the acidity of the catalyst surface.The following conclusions are obtained:1.Adding pore-forming agent and binder's catalysts pore structure is greatly improved by the pore size characterization test.Overall,CMC's pore-forming character is better than cellulose.The CMC=3wt%of the catalytic activity is the highest,the conversion rate of methane and carbon dioxide at 1100? are 100%and 85.O₂%,respectively.But MCC=3wt%at the same temperature,the conversion rate of methane and carbon dioxide are 100%and 79.84%.2.The addition of Ca catalyst performance is higher than adding of Mg in the temperature range of 700??1100 ?.At 1100 ?,the conversion rate of carbon dioxide are 73.32%and 67.03%,respectively.3.On the XRD patterns of fresh catalyst containing Ca and Mg,NiAl2O4 peaks occur in the dispersion and peak intensity weakens more obviously then catalysts without these additives.It reveals that lkaline earth metals of Ca and Mg could inhibit NiAl2O4 growing,which can promote catalytic properties.4.From the overall comparison,increasing catalysts specific surface area is more effective way to improve catalyst's reaction performance in this experimental system.