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Show 5 At 10 ppm of NOx referred to 3% oxygen the rate of NOx emission is 0.016 lbs/million BTU of heat release, or about .020 lb of NOx/million BTU delivered (assuming 80% system efficiency with RRB). Typical low NOx burners of present types where low NOx values by previous industrial standards is of the order of 50 ppm, would emit about .12 lbs/million BTU (at more typical industrial furnace efficiency of 60%). Electrically heated furnaces operating at a typical 70% efficiency, and using electricity generated by a gas fired, 35% efficient power plant emitting 0.1 lbs of NOx/million BTU would function at 0.4 lbs of NOx/million BTU delivered to the furnace, or 20 times that emitted by an RRB furnace. For comparison, with conventional burners high temperature steel heating processes required for rolling and shaping would cause the generation of about 0.3 lbs of NOx/ton of steel, or about 0.4 to 0.5 lbs of NOx/million BTU delivered to the steel, when using conventional burners. Also, gas fired aluminum melters operating at about 25% efficiency would typically require about 4 to 5 million BTU to melt one ton, representing about 1.1 million BTU/ton delivered to the melt. With conventional gas burners generating about 50 ppm of NOx, the NOx generation would be about 0.3 lbs of NOx/million BTU delivered to the melt. All of these typical NOx emissions could be cut by huge amounts using the RRB at less than 10 ppm NOx generation. Conclusion The most succinct conclusion to draw from this project is that NOx levels of a new class of high temperature, high efficiency, industrial, regenerative radiant burners can be held well below 10 ppm, referred to 3% oxygen in the products of combustion, even with air preheat into the 1600 to 1700 F range, surface temperature in the 2400 to 2600 F range, and load temperature in the 1700 to 1850 F range; and further improvement is possible, as concluded from observed short-comings in the research burner test rig. Acknowledgment MKE, Inc. gratefully acknowledges the support of the Southern California Gas Co., South Coast Air Quality Management District, and Zwick Energy Research Organization without which the concept could not have been proven. |