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Show A second series of tests was scheduled to evaluate the new reduction catalyst in conjunction with the original oxidation catalyst for step 6. A test plan for evaluating the effects of the new reduction catalyst on the Hybrid Low NOx Cogeneration Process was prepared. Results presented in this paper are from the second demonstration test, which was performed in Harima in January 1990. The modified process is shown schematically in Figure 1. The NOx source was a diesel generator with a maximum output of 87.5 kw. Other loads tested were 25 kw, 50 kw, and 75 kw. The diesel offgas at 87.5 kw output contained 11.4% oxygen and 1450 ppmv NOx • The maximum exhaust flow rate was approximately 600 Nm3/hr. Exhaust gas from the diesel generator was routed to the reduction furnace. Before entering the reduction furnace, the exhaust gas was mixed with an excess of propane fuel so that oxygen in the exhaust was reacted to extinction at reduction furnace temperatures of 1200 to 1500 C. Excess combustibles-co and H2--were formed as indicated by a co reading of 0.5 to 2 percent. Effluent from the reduction furnace was cooled to approximately 275 C by a water-cooled heat exchanger. A heat exchanger bypass duct with a water-cooled butterfly valve allowed bypassed hot (about 650 C) flue gas to mix with the heat exchanger exhaust to provide a reduction catalyst inlet stream temperature of approximately 400 C. Excess combustibles from the reduction catalyst bed were controlled at 500 to 1500 ppmv co by adding combustion air to the products just upstream of the reduction catalyst. This was done to minimize the formation of by-product bound nitrogen compounds. Products from the reduction catalyst bed were mixed with additional air in a mixing chamber and routed to the oxidation catalyst bed. Here, excess combustibles were oxidized to below 50 ppmv CO by maintaining an outlet oxygen concentration of approximately 1.5 to 3.0 percent. The temperature of the exhaust gas leaving the oxidation catalyst bed was approximately 500 C. RESULTS This section summarizes the results of the January demonstration tests. The process was evaluated with the diesel operating under two different loads: 87.5 and 50 percent. Testing was conducted during each steady-state load condition. Characterization of the Low NOx process was based primarily on continuous emission monitoring (CEM) for NOx ' CO2 , CO, and O2 • Process temperature and pressure data were also collected. These data were supplemented with integrated grab sample measurements for moisture, particulate matter, ammonia, cyanide, organic nitrogen, and hydrogen (see Table 1). Gas flow -4- |