Characterization and performance evaluation of Ni based catalysts with Ce promoter for methane and hydrocarbons steam reforming process
Abstract The Ni Ce/Al steam reforming catalysts with Ni loading 13 wt% and Ce loading 0 2.0 wt% were prepared to study the effects of cerium addition on the catalytic performance for methane and hydrocarbons steam reforming, combining with characterizations of BET, N2 adsorption/desorption, TPR, H2 chemisorption, XRD, and TEM. The optimal intrinsic activity was achieved over Ni Ce/Al (1.02 wt% Ce) by atmospheric pressure micro reaction device at steam/methane of 3.0, CH4 space velocity of 10,000 h 1 and temperature of 450 750 degC. The optimal pressurized activity and stability was also achieved over Ni Ce/Al (1.02 wt% Ce) with the carbon conversion of 75% of the light hydrocarbons at H2O/C of 2.7, carbon space velocity of 6000 h 1, the bed temperature of 480 580 850 degC (entrance 2/3 export) and the pressure of 3.0 MPa, and 100% of hydrocarbons were reformed into CH4, CO, CO2, H2 without C2 or others. It was indicated that the addition of small amount of cerium can improve the dispersion of nickel and inhibit carbon deposition, but more amount of cerium addition was not favorable for nickel dispersion due to the blocking of active sites. Among the catalysts tested, Ni Ce/Al (1.02 wt% Ce) catalyst with the smallest average nickel diameter exhibited the best catalytic performance and the strongest resistance toward carbon deposition maintaining the Ni particle size of 13.0 nm after 300 h experiment.