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Show 0.3 1---------------------------, "5" ~ 0.2 ~ ~ ~ m 0.1 ~ o~~====~~~-=~~------------~~~~~~=-~----~ en :::> z ~ (0.1) ~ @ (0.2) a: o tu (0.3) z Zero Gas Benefit = Annualized Capital Investment (0.4) ~---...I....------L...-----L ___ ---L ___ __..i ___ ___.J o Efficiency only o 5 Efficiency and Emissions Credits 6 Capacity = 250MMBtu!hr; Cap. Factor=70% Gas Cost = $2.6211000cft; Cap Invest=$290K Base coal cost = $30/ton (12,000 Btu/lb) 10 15 20 PERCENT COFIRE (HHV BASIS) Efficiency, Emissions and Capacity Recovery o Efficiency, Emissions, Capacity, and Other * Figure 2. Net credits of cofire in coal stokers 25 All others plus ESP Offset • 30 system interruption where a major portion of boiler load could be provided by the gas burners alone. TEST BOILER Dover Light & Power operates a Babcock & Wilcox spreader stoker fired boiler which powers a steam turbine electric generator system which generates 15.5 MW electric output at the maximum boiler capacity of 165,000 lb jbr steam. The boiler, shown schematically in Figure 3, was installed in 1960. It is equipped with four Detroit Rotograte spreaders, an economizer, four mechanical dust collectors and an ESP which was retrofit. The unit uses ash reinjection from the superheater hopper but has bypassed the asb reinjection from the mechanical collectors due to abrasion problems. The boiler has two elevations of 18 overfire air ports on both the front and rear walls. The upper rows have been closed off 9 |