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SCALE-UP OF A HIGH-THROUGHPUT GASIFIER TO PRODUCE MEDIUM-BTU GAS FROM WOOD
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A schematic flowsheet of the gasification process under development under U.S. DOE’s sponsorship at Battelle’s Columbus Laboratories is shown in Fig. 1. The process employs a hot-sand phase as a conveying and heat transfer medium. By use of such heat transfer methods, it is possible to produce a 500 Btu/SCF fuel gas from biomass without using oxygen. Wood is fed into the gasifier with no pretreatment except partial drying to utilize sensible heat present in the flue gas from the combustor. The wood (or other biomass) is gasified at throughputs up to 2000 lb/h ft of reactor area to produce the fuel gas and a small quantity of char (typically 20% of the dry wood fed). The char and sand then are removed from the gas phase and transferred to the combustor, where the char is burned. The combustion reactions reheat the sand, which returns to the gasifier to provide the heat for gasification .