Chapter 5 - Fluidized Bed Combustion and Coal Gasification

Abstract

Fluidized bed power plants offer an alternative to the pulverized coal-fired plant. The fluidized bed design is especially useful for smaller plant sizes and for burning low quality fuels. The earliest fluidized bed was the bubbling bed, developed by Fritz Winkler. A later design, the circulating fluidized bed, superseded this as the most popular type for power generation. A pressurized version of the bubbling bed reactor has also been developed. This produces high pressure, hot flue gases that can be used to drive a gas turbine as well as using the reactor to raise steam for a steam turbine. Fluidized beds have the advantage of being able to capture sulphur within the bed, with the addition of limestone, thereby reducing sulphur dioxide emissions from the boiler. Another way of using coal to generate electrical power is to gasify it, turning it into a gas that can be burnt to provide energy. The most popular way of carrying this out is in an integrated gasification combined cycle power plant that uses both gas and steam turbines to extract energy from the gasified coal.