| OCR Text |
Show required to utilize these fuels is discussed, and typical boiler performance data are presented. COAL SLURRY RETROFIT TECHNOLOGY Coal slurries as alternate fuels have been evaluated in 700-hp and 100-hp combustion test facilities at PETC. The 700-hp test facility is equipped with an oil-designed, package, two-pass, water-tube boiler (Figure 1), which has a heat liberation rate of 47,100 Btu/ft3-hr and generates 24,000 lb/hr of steam at 175 psig at full load. The 100-hp test facility is equipped with an oil-designed, package, four-pass, firetube boiler (Figure 2); it has a heat liberation rate of 184,000 Btu/ft3-hr and, at full capacity, generates 3,450 lb/hr steam at 100 psig. The test facilities share common No. 6 fuel oil storage, coal storage, and pulverization systems. However, they have separate systems for .coal slurry preparation and transport, baghouses for fly ash control, and systems for flue gas desulfurization. Detailed descriptions of both combustion test facilities have been given previously (1,2,4,12). Coal Slurry Preparation and Handling Coal slurries are prepared in mix tanks at the test facilities and then transferred to hold tanks before being used. Both mix tanks and hold tanks are steam-jacketed and equipped with mechanical agitators. Turbine-blade-type and propeller-type agitators have been used with satisfactory results. The high viscosities of coal slurries require the use of steam-jacket heating surrounding the tanks to facilitate slurry mixing and pumping. External recirculation of slurries from the bottom of the tanks to the top also improves the temperature control and the consistency of the slurry fuels. During CWM preparation, additional mixing was provided by the vertical motion of compressed air bubbles introduced by bustle pipes installed inside the bottom of the mix tanks at both facilities. 14-3 |
