Hydrogen production from high temperature pyrolysis/steam reforming of waste biomass: rice husk, sugar cane bagasse, and wheat straw

Hydrogen production from pyrolysis, steam reforming, and catalytic steam reforming of sugar cane bagasse, wheat straw, and rice husk were investigated using a two stage pyrolysis-reforming system. Biomass samples were pyrolyzed in the first stage, and the volatiles and liquids were reformed in the second stage in the presence of steam. During all experiments, a high temperature of 950 °C was chosen for both the pyrolysis and reforming stages. As compared to low temperatures, pyrolysis/reforming carried out at higher temperature showed higher gas yields, particularly hydrogen gas yield. In addition, dolomite and 10 wt % Ni-dolomite were used to investigate the catalytic steam reforming of the biomass. In terms of hydrogen production, steam reforming using 10 wt % Ni-dolomite was the most effective, producing 25.44, 25.41, and 24.47 mmol of hydrogen per gram for rice husk, sugar cane bagasse, and wheat straw, respectively. The amount of deposited carbon on the reacted catalyst was from 1.31 wt % to 10.13 wt % and was in the form of amorphous and graphitic carbon. Relatively lower carbon deposits were found on the 10 wt % Ni-dolomite as compared to the calcined dolomite. XRD analysis of the reacted catalyst showed the presence of Ni, NiO, and NiMgO phases for the 10 wt % Ni-dolomite. The highest hydrogen yield of 25.44 mmol g was obtained from rice husk, and the highest hydrogen concentration in the gas mixture was found to be 59.14 vol % from rice husk using 10 wt % Ni-dolomite.