Selective production of hydrogen by steam reforming of glycerol over Ni/Fly ash catalyst

Abstract

Hydrogen was produced with high selectivity by steam reforming of glycerol over a novel fly ash based catalyst. The catalysts were prepared by impregnating fly ash with varying amounts of nickel and were characterized suitably by XRD, FESEM, EDS, BET and TPR techniques. The catalyst containing 7.5wt% Ni on fly ash gave highest hydrogen yield in the glycerol steam reforming reaction. A complete process development was carried out with the best catalyst by varying three important process parameters, namely temperature, glycerol to water molar ratio and space-time. A maximum yield of 5.8mol of hydrogen per mole of glycerol fed was produced at 550°C with steam to glycerol molar ratio of 12 and a space-time of 8.4kg cat h/kmol of glycerol fed with 98.6% conversion of glycerol. Two kinetic models (power-law type and LHHW type) were developed from the experimental data obtained under reaction conditions free from mass transfer limitations. The activation energy of the glycerol reforming reaction as determined from both the models was 30.0kJ/mol.