Particulate removal from high-temperature, high-pressure combustion gases

Abstract

The adoption by utilities of coal-fired pressurized fluidized-bed/combined cycle combustion systems for electric power generation depends to a large extent on the development of an efficient and economic cleanup system for the high-temperature, high-pressure combustion gases. For adequate turbine protection, these gases must be sufficiently cleaned to bring particulate erosion and alkali vapor corrosion to a level acceptable to gas turbine manufacturers. At the same time, the total particulate content of the flue gas must be reduced to the limit set by the Environmental Protection agency. To accomplish particulate removal from a dust-laden gas stream, a number of separation devices have been developed. These include conventional and augmented cyclones; porous metal, fiber, fabric, and ceramic filters, as well as fixed, moving, and fluidized-bed granular filters; and electrostatic precipitators. Several other novel separation devices have been proposed and developed to different degrees such as: contactors using molten salt, metal, or glass, dry scrubbers, acoustic agglomerators, as well as cyclones and granular-bed filters with external electrostatic or magnetic fields. Some of these separation devices in various combinations have been tested in process development units or in hot gas simulators by ANL, CPC, CURL, CW, Exxon, GE, Westinghouse, etc. The results are discussed and evaluated for PFBC applications.