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Show (4) Leakage of ammonia The result of periodic sampling during the experiment of denitration shows that the leakage of ammonia was less than 40 ppm when the temperature of the spray point was over 800°C. This concentration is small and causes no problem. 4. Application to the Regenerative Ceramic Burner ... Application Case (2) Each regenerative ceramic burner consists of a pair of burners with ceramic heat accumulators as shown in Fig. 13. The two burners repeat combustion cycles and heat accumulation cycles alternately. The heat stored during the heat accumulation cycle is used to preheat air during the combustion cycle. Although this burner is of simple in structure, its thermal efficiency is high and it can be used even for high temperature. However, it produces highly concentrated NOx because of the high air preheating temperature. In the test using COG, the concentration of NOx was as high as 180 ppm (at 11% 02) on average. Therefore, it became clear that this burner cannot be used without taking corrective measures because of the environmental problems it might cause. So, we tried to decrease NOx by applying the non-catalytic ammonia denitration method. For developmental purposes, we assumed that the temperature of the furnace was 700 to 850°C, considering application of this burner to a heat treatment furnace for sheet coils. Furnace . '. '. : .... : .. . ; Fuel -""_----'- Fuel Comtusflon air r Combus tion air Fig. 13 Regenerative Ceramic Burner 4-1 Testing Device We made an experiment by using· a bench test model as shown in Fig. 14. Its specifications are shown in Table 3. We. installed reaction chambers before the heat accumulators, considering reaction temperature. The same amount of by-product liquid ammonia as the estimate amount of NOx, in terms of mol, was dripped only on the exhaust heat recover sides. In the reaction chambers, COG can be also added. -7- |
