Study On Methanation Performance Of Carbon Monoxide On Ni-based Catalyst

With the rapid development of world economy, the demand of energy is greatlyincreasing and energy comsumption structure is changing to a great extent. As a kindof clean energy, syngas has attracted much attention from both academic and industry.Methanation reaction is the key step in the process of coal-derived natural gas and themost important is to develop effective methanation catalyst. Ni-based catalysts havebeen widely employed for methanation reaction because of their low cost, highcatalytic activity and high selectivity for methane. The performance of catalyst wassystemly investigated and the relationship between phase structure, surface property,chemical composition and reaction performance was discussed at the end of thispaper.Ni/Al₂O₃catalysts with varied Ni contents were prepared by impregnationmethod for syngas methanation. The effect of Ni loading on the activity of Ni/Al₂O₃catalysts for methanation reaction was studied and the Ni loading about11%weightpercent showed good high temperature stability. Effect of temperature and GHSV onmethanation activity of the catalysts were investigated. The results showed that theoptimum temperature was550℃. During space velocity from7500h^-1to30000h^-1,CO conversion increased with the increase of space velocity and then decreased. Thecatalyst achieved the maximum activity at GHSV=15000h^-1.Three kinds of hydrotalcite with different nickel content were prepared usingco-pecipitation method. The methanation activity was tested under the condition ofGHSV as15000h^-1, reaction temperature as600℃, n（H₂）/n（CO） as3. Also, thefluctuation of activity with temperature was investigated at different n（H₂）/n（CO）ratio. The results indicated that CO conversion and CH4selectivity on NiMg8washigher than that on NiMg5and NiMg6.By comparing methanation activity of NiMg8and11%Ni/Al₂O₃catalyst, it wasfound that the activities of these two catalysts were similar at n（H₂）/n（CO） as3or2.However, the stability of11%Ni/Al₂O₃was good while NiMg8catalyst lost itsactivity after2.5h reaction at n（H₂）/n（CO） as1.