Babcock & Wilcox CFB boilers — design and experience

Abstract

BR-1711 Abstract The distinctive feature of Babcock & Wilcox (B&W) CFB boilers is a two-stage solids separation system consisting of the impact-type primary solids separator (U-beams) and the sec- ondary multi-cyclone dust collector. Lessons learned from 15 years of B&W's CFB technology application have been used to develop a reliable, low cost boiler design. Advantages of boil- ers with a two-stage solids separation system are described. Op- eration of B&W coal-fired CFB boilers over the last 10 years has demonstrated high reliability of the two-stage solids sepa- rator. Superior solids collection efficiency of the two-stage sepa- rator provides higher furnace heat-transfer rate, ability to better control furnace temperature, and increased residence time of fine carbon and sorbent particles. As a result, the required boiler performance is achieved with lower furnace height and smaller boiler footprint. The current B&W IR-CFB boiler design is de- scribed. Compactness of the IR-CFB makes it especially attrac- tive for PC boiler retrofit applications. Considerations for IR- CFB scale-up are provided.