Design and performance of a multi-fuel boiler system

A 1300-psi boiler generating 650,000 lb/h of steam and capable of using a combination of No. 2 and No. 6 fuel oil, pulverized and stoker coal, and biomass from whole-tree chips and wastewood by-products was started-up 2 and a half years ago in combination with a 47-MW double-extracting turbine. Although supporting auxiliary systems are discussed briefly, major emphasis is on the design and operation of the multi-fuel boiler's combustion system, which provides the plant's fluctuating steam and power demands and sends excess power to a local utility. The system's control network, which includes a sophisticated instrumentation system, several programmable logic controllers, and a computer, is also described.