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Show Eli Lilly and Company The Eli Lilly and Company's Tippecanoe Laboratories facility in Lafayette, Indiana, is a research and pharmaceutical manufacturing facility. Currently, the facility operates five boilers. Three of these are 1952 vintage Babcock & Wilcox "F' type spreader stokers with a maximum steaming capacity of 65 kpph per boiler, at 400 psig and 720°F superheat. Each has three Detroit Rotograte spreader stokers. The main use of process steam is by the fermentation plant, which can have changes in demand of 40-kpph at relatively short notice. This requires a fair amount of manual communication between the fermentation area and the powerhouse in order to prepare the coal boilers to respond to load changes without opacity increases. Each coal boiler is equipped with a superheater, an economizer, and a mechanical dust collector. Prior to the gas cofiring system's installation, the boilers were started up by a wood fire that was built on the coal grates and ignited with propane. Opacity increases were often observed during startup. Other operational problems resulted from furnace slagging and the combustion of wet coal, both of which led to a loss of capacity and increased maintenance and operator attention. Boilers Nos. 1 and 3 were retrofit with Coen CoFyr burners in November 1997 through January 1998, and Boiler No. 1 was tested in M a y 1998. The combined firing capacity of the gas burners retrofit to each boiler was 50 MMBtu/hr. The primary incentives for the gas cofire systems at Lilly was to allow rapid, smokeless startup, improved load-following capability, and ease of lower boiler furnace slag removal during operation. Boiler No. 1 was tested at two loads, 40 kpph and 65 kpph. Tests were also conducted over repeated load swing cycles. Measurements included continuous monitoring of 02, C O , C 0 2 , N O x , and S02, E P A Method 5 for particulate, Andersen impactors for particle sizing, and grab samples for fuel and ash streams. Figure 7 shows the response of NOx emissions to cofire for the two loads tested. Gas cofire in the range of 10 to 15 percent reduced N O x emissions by 15 percent. These reductions are greater than those corresponding to the displacement of coal with gas fuel. S 0 2 emission reductions were entirely consistent with the displacement of coal with gas. In a load following test at nominally 10-percent gas cofiring, which included two load swing cycles with boiler load varying from 50 to 60 kpph, stack opacity was at or under 20 percent and integrated stack particulate concentration was in the range measured at steady, low-load operation. In contrast, in a load following test with no gas cofiring, with three load swing cycles varying from the 45- to 50-kpph range to over 60 kpph, stack opacity was about 30 percent near the low end of the load swing range, but increased to almost 40 percent during load ramp up. Integrated particulate emissions over the three load swing cycles were in the range measured for steady operation at high load with no gas cofiring, and were twice the level measured during the load swing test with gas cofiring. Based on results of these tests, and the overall positive experience with cofiring or the two units originally retrofit, Lilly purchased a third cofire system and retrofit it to Boiler No. 2, the third coal-fired stoker in the powerhouse. Purdue University Purdue University in West Lafayette, Indiana, operates two coal-fired stoker boilers at its Wade Utility Plant. Boiler No. 1 is a Babcock & Wilcox ( B & W ) unit installed in 1961. Boiler No.2 is a Wickes/ Combustion Engineering (CE) unit installed in 1966. Both are capable of producing 215 kpph of steam at 650 psi and 825°F superheat, but both have been derated to 165 kpph because of excess opacity at higher loads. Each boiler's particulate emissions are limited to 0.7 lb/MMBtu heat input, with rriaximum stack opacity o( 40 percent, 6-minute average. Both limits have been difficult to comply with at boiler loads over 165 kpph. and the opacity limit is routinely exceeded during boiler startups. 9 |