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Show Paper Presented at the 1999 AFRC International Symposium. San Francisco. California, October 3-6 ADVANCES IN LOW NOx RESIDUAL OIL FIRING FOR BOILERS Scott A. Drennan* Mandayam Vijay Coen Company, Inc. 1510 Rollins Road Burlingame, CA 94010 (650) 697-0440 phone (650) 686-5655 fax ABSTRACT Residual oil continues to be the fuel of choice for many industrial steam users while environmental regulations allow its use. However, new emissions regulations on N O x and SOx are requiring substantial improvements in emissions performance or it will be regulated out of existence. This paper discusses the results and effectiveness of two applications of low N O x design modifications to residual oil firing industrial boilers. A comparison of the low N Ox approaches required and results obtained for a package and field erected boiler are presented. Previous development in low N O x residual oil firing indicate that significant N O x reduction can be obtained through spray pattern modification to produce a staged spray flame with rich and lean zones. Industrial package boilers have specific performance criteria that impede the effectiveness of such low N O x techniques. Factors such as smaller furnaces, higher firing densities, lack of air preheat, widened operating envelope, simple controls, and variable fuel quality make the industrial package boiler a more challenging low N O x environment than a multiple burner field erected or utility boiler. The greatest N O x reductions are obtained in field erected boilers with low firing densities as a result of the ability to stage the combustion. The variability in fuel characteristics such as viscosity, distillation curve, carbon residue, and ash composition limits the potential emissions reduction and maintaining stable combustion. " Corresponding Author: sdrennan@coen.com |