Task 4 -- Conversion to a coal-fueled advanced turbine system (CFATS)

Solar is developing the technologies for a highly efficient, recuperated, Advanced Turbine System (ATS) that is aimed at the dispersed power generation market. With ultra-low-emissions in mind the primary fuel selected for this engine system is natural gas. Although this gas fired ATS (GFATS) will primarily employ natural gas the use of other fuels particular those derived from coal and renewable resources cannot be overlooked. The enabling technologies necessary to direct fire coal in gas turbines were developed during the 1980`s. This Solar development co-sponsored by the US Department of Energy (DOE) resulted in the testing of a full size coal-water-slurry fired combustion system. In parallel with this program the DOE funded the development of integrated gasification combined cycle systems (IGCC). This report describes the limitations of the Solar ATs (recuperated engine) and how these lead to a recommended series of modifications that will allow the use of these alternate fuels. Three approaches have been considered: direct-fired combustion using either a slagging combustor, or a pressurized fluidized bed (PFBC), externally or indirectly fired approaches using pulverized fuel, and external gasification of the fuel with subsequent direct combustion of the secondary fuel. Each of these approaches requires substantial hardware and system modifications for efficient fuel utilization. The integration issues are discussed in the sections below and a recommended approach for gasification is presented