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Show BENEFITS AND TECHNICAL CONSTRAINTS OF USING OXYGEN The use of oxygen or oxygen enriched air in place of air for incinerati on can improve the overall performance and efficiency of chemical waste incinerators, inc reasing throughput, improving ORE, and overall, reducing the cost of the system. As oxygen replaces part or all of the air for incineration, the nitrogen portion i s reduced in both the oxidant and the flue gas. Hence, the volume of the oxidant and the flue gas are reduced per unit of waste processed. In addition, the concentration of oxygen in the fuel-oxidant mixture is increased . The main advantages accrued from these changes are (1) the throughput of the incinerator, which is normally limited by the air blower capacity, the gas residence time and the size of the flue gas cleaning system when using air, can be significantly increased; (2) the fuel consumption, if supplemental fuel is required, is lowered primarily due to the reduced sensible heat loss to the flue; (3) the ORE should be improved due to the higher oxygen concentration in the fuel-oxidant mixture and longer residence time; and (4) pollution control of the reduced flue gas is less costly and more effective. A summary and detailed discussion of these benefits were provided in a previous presentation (5). Unfortunately, the use of oxygen in conventional burners for hazardous waste incineration applications suffers the disadvantages of (1) high flame temperature, resulting in high NOx and local overheating, and (2) poor mixing and poor recirculation of the gases within the combustion chamber. These technical constraints restricted most people to the use of oxygen at only modest enrichment level. In order to overcome the disadvantages noted above, the Aspirator Burner or "A" Burner was developed [3&4). The key feature of the "A" Burner is that the furnace gases are aspirated into the oxidant jets prior to mixing with the fuel, as indicated in references 4 and 5. By maintaining sufficient distance between the oxygen jets and fuel supply, enough of the furnace gases can be aspirated into the oxygen jet prior to mixing with the fuel so that the resulting flame temperature can be reduced to a value equivalent to an air flame temperature. Gas mixing and recirculation wi thin the furnace is accomplished wi th the "A'· Burner by using very high velocity oxygen jets, which result i n a uniform temperature distribution within the incinerator. Figure 1 shows a commercial full-scale "A" Burner for industrial furnaces. OPERATING RESULTS AND DISCUSSION Operation of the modified HIS, from early June to mid-September 1987, confirmed that the system had achieved the following: (1) throughput increase (2) kiln puff reduction (3) specific fuel savings over 60~, (4) NOx emission comparable to air systems, and (5) good flame stability and operational flexibility. Each of these achievements is described below. - 3 - |