抄録
Carbon dioxide reforming of methane to synthesis gas over an alumina-supported 1% Ni-based catalyst was investigated at atmospheric pressure. The reforming reactions were carried out using 500-800°C reaction temperatures. The catalyst activity and stability, carbon deposition, and synthesis gas H2/CO ratio were determined. XRD, SEM, TGA and TPD techniques were used to characterize the spent and fresh catalysts calcined at 900°C. Further investigations were performed at 600°C to reduce catalyst deactivation due to coking. It was observed that, increasing reaction temperatures from 500 to 600°C increased the formation of carbon; however, further increase of reaction temperature to 800°C decreased the formation of carbon. The highest CH4 and CO2 conversion drops were recorded at 600°C. Investigations at 600°C revealed that addition of Ca promoter decreased coke formation and therefore, enhanced the stability of the catalyst. Also, the combined partial oxidation increased the activity and reduced carbon formation. The optimum catalyst performance with respect to O2 addition was obtained with a feed containing 20% O2. On other hand, when the CO2/CH4 feed ratio is increased from 0.65 to 1.50 the drop of CH4 conversion with time-on-stream was reduced from 65% to 15%. The best catalytic performance was achieved with a space velocity of 33 ml/min.gcat.
