Conversion of toluene (model tar) in the presence of syngas using selected steam reforming catalysts

Ethanol production through the thermo-chemical route uses syngas as a raw material. It is important to clean syngas produced from gasification of its tars before its final intended use. Three different commercial catalysts (one platinum based and two nickel based)- Cerium Zirconium Platinum, Hifuel R110 and Reformax 250, were investigated for their ability to reduce toluene (model tar). Studies were carried out in a fixed bed reactor using a gas mixture mimicking syngas composition produced from switchgrass gasification. The operating parameters tested were space-time (6.86x10-4 - 1.262x10 -3 kg hr m-3) corresponding to different catalyst loading and catalyst particle size (pellets and powder). Temperature studies were conducted on Cerium Zirconium Platinum catalyst. Decreasing the particle size resulted in better toluene conversion for all three catalysts. Additionally, an increase in space time lead to an increase in toluene conversion. Furthermore, an overall increase in H2 and CO2 concentration and an overall decrease in CH4 and CO concentration were observed during toluene conversion. Temperature also played a significant role in converting toluene. Conversion of toluene increased by 1.6 times due to an increase in temperature from 600-800 °C. Rate constants were calculated for all three catalysts. Apparent activation energy for steam reforming of toluene in the presence of syngas mixture for Cerium Zirconium Platinum catalyst was found to be 64.74 k mol-1.