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Show CONTROL OF NITROGEN OXIDE EMISSIONS IN GAS-FIRED HEATERS - THE RETROFIT EXPERIENCE Gregory P. Cfoce and Rasik Pat.el Kinetics Technology International Corporation Monrovia, California 91016 RaW\iit Sahn California Institute of Technology Pasadena, California 91125 ABSTRACT PAPER NO. 52 Clean air legislation in the United States will continue to mandate reductions in the quantities of nitrogen oxides emitted by process heaters and boilers in petroleum refineries. Already, significant controls are required for_ such units operating in Southern California. The South Coast Air Quality Management District, responsible for maintaining clean air in that region, currently requires the most stringent controls for nitrogen oxides anywhere in the United States. A significant aspect of these regulations is that they apply to existing heaters and boilers and not new units. Retrofitting existing units to reduce their emissions subject to various other constraints is often a challenging task for the engineer and designer. It is also a subject that has not received adequate exposure in the literature, where most discussion is limited to technology applicability in new designs. This paper describes the various constraints faced by designers in applying present NOx reduction technology to process fired heaters. It includes actual examples of the successful implementation of these technologies. 1. INTRODUCTION Clean air legislation in the United States, including the recent amendments to the Clean Air Act [1], will continue to mandate reductions in the quantities of nitrogen oxides emitted by process heaters and boilers in petroleum refineries. Nitrogen oxides are also precursors of ozone and particulates, both significant constituents of urban smog. Many refineries in the United States are located in urban areas that have poor and/or deteriorating air quality. Additionally, all regions of the country have to be in compliance with the National Ambient Air Quality Standards (NAAQS) [2] for priority pollutants including nitrogen oxides and ozone by the year 2010. Thus, significant controls are and will continue to be imposed on process fired units in petroleum refineries to reduce their NOx emissions. Already, extremely stringent controls are required for such units operating in Southern California, the region with the worst air quality in all of the United States. The South Coast Air Quality Management District (SCAQMD), responsible for attaining and maintaining the NAAQS in that region, currently requires the most stringent controls for nitrogen oxides anywhere "in the United States [3]. In this paper, the word "heater" will generally be used to describe any kind of refmery fired unit, whether process heater or boiler. Where differences between process heaters and boilers are important, the discussion will make that distinction clear. This paper deals with the retrofit situation as it applies to heaters in the Southern California region. A particular region had to be chosen to limit the scope of the discussion and to provide a meaningful context. However, virtually all of the 1 |