The CO₂ reforming of the hydrocarbons present in a model gas stream over selected catalysts

Three catalysts (3:17 Ni/Al co-precipitated, 1 wt.% Ru/Al₂O₃, 1 wt.% Pt/ZrO₂) were investigated for the dry reforming of the CH₄ and C₃H₈ present in a model gas stream similar in composition to that from (steam) biomass gasification (42 mol% H₂, 15.5 mol% CO, 5.1 mol% CH₄, 19.0 mol% CO₂ and 18.3 mol% C₃H₈). At low temperatures over each of the catalysts (450-550 °C) the CH₄ content of the gas stream was increased with a significant decrease in the H₂, CO₂ and C₃H₈ contents. At 800 °C, the CO₂ content of the gas stream was completely consumed via the dry reforming reaction. Coke deposition due to the cracking of the unreformed hydrocarbons was observed. The resultant gas stream for all the catalysts investigated contained a reduced mol% concentration of hydrocarbons; however, the methane content was unacceptably high for an IGCC process. An increase in the CO₂ content of the gas stream to 46.1 mol% prior to introduction to the catalysts at 800 °C gave the order of activity of the catalysts as Ni/Al>Ru/Al₂O₃>Pt/ZrO₂. The resultant gas stream with the Ni/Al catalyst contained 0.6 mol% hydrocarbon (CH₄) and a syngas ratio of 1.