Hydrogen-rich gas production from biomass catalytic gasification

With the use of dolomite in the fluidized-bed gasifier and the use of nickel-based catalysts in the fixed bed reactor downstream from the gasifier, the characteristics of hydrogen yield from biomass are investigated in the present study. Some calcined dolomite is placed initially in the gasifier with an amount of 120 g/(kg h^-1) biomass. To replace the eroded and elutriated dolomite, calcined dolomite (0.3-0.45 mm) is continuously fed and its feeding rate is determined by preliminary test. The influence of the operating conditions in the catalytic reactor on the production of gases, especially H₂, is studied over the temperature range of 650-850 °C, for weight hourly space velocity (WHSV) in the range of 2.68-10.72 h^-1. In the gaseous product, the average content of H₂ exceeds 50 vol %; C₂ content is lowered to below 1 vol %, and nearly half of CH₄ is converted after the catalytic reactor. Over the ranges of experimental conditions examined, the highest gas yield reaches 3.31 Nm³/kg biomass, wet basis; the maximum hydrogen yield reaches 130.28 g H₂/kg biomass, wet basis. This system shows a good performance over a lifetime test of 350 min.