Abstract

Carbon dioxide reforming of methane to synthesis gas over Ni on a mixed (α-Al₂O₃ and TiO₂-P25) support was investigated. The effect of adding Zr and Ce promoters to the supported catalyst was studied. Catalytic testes were performed at atmospheric pressure, flow rate of 33 ml/min and various reaction temperatures in the range of 500 and 800°C. The influence of several operating conditions such as feed ratio, space velocity and oxygen addition (that is, combined dry reforming and partial oxidation) on catalyst activity, stability and synthesis gas ratio (H₂/CO) were studied. Spent and fresh catalysts were characterized by scanning electron microscopy (SEM) and thermogravimetric analysis (TGA) techniques. The lowest carbon formation on the catalyst was attained at 800°C. Zr gave highest promotion and best stability. For the 1%Ni+0.15%Zr catalyst over 80% a- Al₂O₃+20% TiO₂ support, the best conversions of CH₄ and CO₂ were 97 and 89.5%, respectively at 800°C and CO₂/CH₄ = 1.3.

Key words: CO₂ reforming, CH₄, supported catalysts, coke, promoter, stability, partial oxidation.