COMBINED STEAM AND CO2 REFORMING OF CH4 OVER NICKEL CATALYSTS BASED ON Al2O3–MO (M= Mg, Ca, Ba)

Abstract

A series of 10 wt% Ni/Al2O3–MO (M = Mg, Ca, Ba) catalyst was prepared by impregnation method for applying in the combined steam and carbon dioxide reforming of methane (CSCRM). In this study, five supported nickel catalysts were impregnated on different supports. All of the supports have been obtained by co–precipitation method and also have been investigated. Several techniques, including N2 physisorption measurements, X–ray powder diffraction (XRD), temperature–programmed reduction using H2 (H2–TPR), and transmission electron microscopy (TEM) were used to investigate catalysts’ physicochemical properties. The results showed that MgO was the most suitable promoter comparing with CaO and BaO in CSCRM. The presence of MgO in Ni/Al2O3 changed catalysts’ characteristics leading to an increase in the catalytic activity and stability with time on stream (TOS). It was found that the suitable catalyst was Ni–based on Al2O3–MgO of mass ratio 2:1 which showed a high metal dispersion as well as dominated spinel structure. The CH4 and CO2 conversion at 800 °C reached 99.8 % and 51.7 %, respectively. Catalytic stability of this catalyst with TOS at 800 °C could reach to more than 20 hours until it started decreasing.