Co-gasification of Coal and Hardwood Pellets: Syngas Composition, Carbon Efficiency and Energy Efficiency

摘要

This paper presents the effect of feedstock mixtures on the composition of syngas produced from a commercially available down-draft gasifier manufactured by All Power Labs (Berkeley, CA). Bituminous coal (Pittsburg seam) and hardwood pellets were usedfor the experiments. Five types of feedstock mixtures having composition of 100% hardwood pellets, 20% coal-80% hardwood pellets, 50% coal-50% hardwood pellets, 80% coal-20% hardwood pellets and 100% coal were prepared. Air or an air/water mist mixturewas used as a gasifying agent and vacuum of 3" water was maintained inside the reactor. Syngas with 20.95% carbon-monoxide and 16.05% hydrogen was produced from the gasification of wood pellets. The hydrogen and carbon-monoxide content in the product gasdecreased with an increase of the coal ratio of the mixtures. A significant increase in carbon efficiency was observed with an increase of the coal ratio in the mixtures. Syngas carbon and syngas energy efficiency increased with injection of the mist along with air in the system for the biomass gasification.