Sorption-enhanced steam methane reforming over Ni/Al2O3/KNaTiO3 bifunctional material

Abstract

The performance of a new lab-made bifunctional material Ni/Al2O3/KNaTiO3 for producing high purity H2 via sorption-enhanced steam methane reforming (SESMR) was investigated. A series of bifunctional materials with 10 wt% Ni loading but different wt% ratios of KNaTiO3 and Al2O3 was prepared by wetness impregnation method. All the materials were calcined at 700 °C for 3 hours and screened for their catalytic activity in a continuous flow fixed-bed reactor. The material containing 50 wt% each of KNaTiO3 and Al2O3 (designated as HM) was found to be the best choice. The optimum process parameters for the production of high purity H2 were determined: temperature = 700 °C, steam to carbon (S/C) molar ratio = 6 and gas-hourly space velocity (GHSV) = 2000 cm3 g-1 h-1. The values of CH4 conversion, H2 yield and H2 purity were 87, 87 and 90%, respectively, at the optimum reaction conditions. The adsorption capacity of HM was found to be 14.7 wt%. With a breakthrough time of 10 min, the material was stable for 8 adsorption-desorption cycles. The regeneration of HM was achieved with N2 gas at the same reaction temperature. Overall, the activity of this material for SESMR was very promising.