Catalytic Steam Gasification of Pine Sawdust. Effect of Catalyst Weight/Biomass Flow Rate and Steam/Biomass Ratios on Gas Production and Composition

Abstract

Pine sawdust catalytic steam gasification has been studied in a fluidized bed at a relatively low temperature, 700 °C. The Ni−Al catalyst used was prepared by coprecipitation and calcined at 750 °C for 3 h. The influence of the catalyst weight/biomass flow rate ( W /mb) and steam/biomass ( S/B ) ratios on the product distribution and on the quality of the gas product obtained was analyzed. An increase of the W /mb ratio increases the total gas, H 2, CO, and CO 2 yields, while CH 4 and C 2 yields decrease. An increase of the S/B ratio increases H 2 and CO 2 yields while CO and CH 4 yields decrease. This fact can be explained by steam reforming and water-gas shift reactions. The increase of the S/B ratio also has a positive effect on the life of the catalyst. The gas composition and gas yields at initial time have also been studied. For W /mb ratios > 0.5 h, the gas composition at initial time is similar to that for thermodynamic equilibrium for different S/B ratios. The influence of the S/B ratio on gas yield at initial time is more marked, up to a ratio of 1.5.