Hydrogen production from yellow glycerol via catalytic oxidative steam reforming

In this research study, a low-impurity product from glycerol purification unit of a biodiesel manufacturing called yellow glycerol, was shown to be an alternative raw material for H-2 generation via oxidative steam reforming reaction over Ni/CeZrO2/Al2O3 catalyst. The effects of operating parameters, such as water-to-yellow glycerol ratio between 3 and 9, reaction temperature in the range of 550-650 degrees C, and oxygen-to-yellow glycerol ratio from 0.25 to 0.75, were explored. Partial oxidation, steam reforming and decomposition of glycerol incorporated with water gas shift reaction were the main reactions involved producing H-2, CO and CO2 as the main gas products. The suitable operating condition found was at water-to-yellow glycerol ratio of 9, oxygen-to-yellow glycerol ratio of 0.5 and 650 degrees C where nearly complete conversion of yellow glycerol was achieved with maximized hydrogen selectivity and yield at 69% and 67%, respectively. This promoted catalyst exhibited superior activity to the unpromoted Ni/Al2O3 in enhancing the main reactions producing hydrogen while strongly inhibiting coke deposition. Compared to pure glycerol, the reforming of yellow glycerol byproduct produced relatively high H-2 yield, 4 mol H-2/mol yellow glycerol vs. 4.9 mol H-2/mol pure glycerol demonstrating that yellow glycerol is an attractive raw material for hydrogen production via the catalytic oxidative steam reforming. (C) 2012 Elsevier B.V. All rights reserved.