Selective catalytic methanation of CO in hydrogen-rich gas with a metal foam microreactor

For the purpose of removing CO to less than 100×10^－6 to meet the demand of the proton exchange membrane fuel cells (PEMFC), a bimetallic catalyst 4Ni-2Ru/ZrO₂ for CO selective methanation was prepared by homogeneously coating on the foam niekel. The effect of space velocity of feedstock, coating methods and calcination temperature on CO selective methanation was investigated in a microreactor.The relationship between the preparation method and activity of the 4Ni-2Ru/ZrO₂ catalyst was also explored by means of X-ray diffraction (XRD) and temperatureprogrammed reduction (TPR). The results indicate that the outlet concentration of CO can be reduced to less than 30×10^－6 at 260℃ and the space velocity from 2000h^-1 to 6000h^-1, with the calcination temperature of 350℃. The outlet concentration of CO can be reduced to 7×10^－6 and the CO2 conversion is less than 1.5% as the space velocity is 5000h^-1.Because of excellent heat transfer and mass transfer ability, the CO conversion can reach a high level more than 99.6% with the outlet concentration below 50×10－6 even at a high reaction temperature of 300℃.