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 H2 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 °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 H2, 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 °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 H2 yield, 4 mol H2/mol yellow glycerol vs. 4.9 mol H2/mol pure glycerol demonstrating that yellow glycerol is an attractive raw material for hydrogen production via the catalytic oxidative steam reforming.