Indirectly Heated Steam Gasification

This process, originally called the Pearson-BrightStar Process, was developed by BrightStar Technology, Inc. It consists of the conversion of biomass feedstocks, particularly sawdust and wood chips, by steam gasification in indirectly heated, tubular reactors to afford synthesis gas suitable for methanol production (Smith, Stokes, and Wilkes, 1993) or a medium-energy gas suitable for use in gas turbines (Menville, 1996). A 0.9- to 4.5-t/day pilot plant was operated in Mississippi with sawdust and wood chip feedstocks, but sewage sludge, other biomass feedstocks, and lignites have been tested. The process gasifies partially dried wood at 10 to 15% moisture content with injected steam at a steam-to — carbon ratio of about 2 at low pressure and high temperature to maximize synthesis gas and minimize methane formation. The process is believed by BrightStar to be the first of its kind to utilize externally heated tubular reactors through which the feedstock and steam are passed. BrightStar Synfuels Com­pany, a joint venture of BrightStar and Syn-Fuels Corp., completed construction of a commercial demonstration module in 1996 in Louisiana. This plant re­quires about 22 dry t/day of wood residue feedstock and has a net energy output of 13.2 GJ/h exclusive of the energy required for reformer firing.