oa South African Journal of Chemical Engineering - Dual fluidized-bed steam gasification of solid feedstock : matching syngas requirements with fuel mixtures
Gasification of solid fuels has attracted increasing interest within the power industry for synthesis processes for liquid and gaseous fuel production. In addition to a high purity of syngas, the tar content and minor impurities (NH3, H2S, HCl), the gas composition has a major influence on the performance of any downstream utilization. The dual fluidized bed gasification technology developed at the Vienna University of Technology has been investigated for biomass use on a pilot scale over the last 15 years. Moreover, this process has also been demonstrated on an industrial scale. Allothermal (indirect) gasification with a solid heat carrier to transport the desired heat for gasification to the gasifier and the utilization of steam as a gasification agent ensures a high quality syngas that is nearly free of nitrogen. Originally designed for wood chips, the system can also handle a large number of alternative fuels. The advantage of fuel flexibility has turned out to be a key issue for the commercial breakthrough of this technology. To point out the influence on the system performance of fuels that have a different origin, wood pellets, as the designated feedstock and hard coal as an example fossil fuel were fed into the DFB gasifier in different blends to generate operating figures for coal ratios from 0% to 100%.
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