Advanced atmospheric fluidized-bed combustion design - spouted bed

This report describes the Spouted-Fluidized Bed Boiler that is an advanced atmospheric fluidized bed combustor (FBC). The objective of this system design study is to develop an advanced AFBC with improved performance and reduced capital and operating costs compared to a conventional AFBC and an oil-fired system. The Spouted-Fluidized Bed (SFB) system is a special type of FBC with a distinctive jet of air in the bed to establish an identifiable solids circulation pattern. This feature is expected to provide: reduced NO/sub x/ emissions because of the fuel rich spout zone; high calcium utilization, calcium-to-sulfur ratio of 1.5, because of the spout attrition and mixing; high fuel utilization because of the solids circulation and spout attrition; improved thermal efficiency because of reduced solids heat loss; and improved fuel flexibility because of the spout phenomena. The SFB was compared to a conventional AFBC and an oil-fired package boiler for 15,000 pound per hour system. The evaluation showed that the operating cost advantages of the SFB resulted from savings in fuel, limestone, and waste disposal. The relative levelized cost for steam from the three systems in constant 1985 dollars is: SFB - $10 per thousand pounds; AFBC - $11 per thousand pounds;more » oil-fired - $14 per thousand pounds. 18 refs., 5 figs., 11 tabs.« less