The Real Cost of NOx Emission Reduction

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AZTTci-^ The Real Cost of NOx Emission Reduction Greg Croce • Tom Gilmore Di KTI Corporation, Concord California t^ (2- P ABSTRACT Clean air legislation in the United States will continue to mandate reductions in the quantities of nitrogen oxides emitted by process heaters, boilers and gas turbines in petrochemical plants. Regulations have been implemented that require not only point source reductions, but overall plant wide reduction of nitrogen oxides. Retrofitting existing fired units to reduce their emissions is often a challenging task for the engineer and designer Available technologies can be used in different applications resulting in significantly different reductions and cost. This paper describes the various constraints faced by engineers in applying present N O x reduction technology to process heaters, boilers, and gas turbines, along with their associated cost. Overall installation cost is evaluated along with nitrogen oxide reduction to determine which technologies are most cost effective in achieving compliance INTRODUCTION Clean air legislation in the United States will continue to mandate reductions in the quantities of nitrogen oxides (NOx) emitted by process heaters, gas turbines, and boilers (referred to as fired units) in petroleum refineries and chemical plants. These regulations apply to existing fired units and not just new sources. In addition, regulations are being promulgated that will affect both individual fired units as well as refinery wide emission levels. Retrofitting existing units to reduce their emission subject to various plant constraints is often a challenging task for the engineer and designer1. Equally complex is the estimation of the total installed cost of these retrofit projects. With the complexity of both the regulations and the nature of the retrofit type of project, it is imperative that the project team determines how to most effectively spend funds to meet regulations. In this paper, w e will review the factors that influence the total installed cost (TIC) in conjunction with the operating and maintenance cost associated with the most commonly used N O x reduction technologies. The "cost effectiveness" approach will be used to evaluate various technologies for given applications. An example will be used to show how cost effectiveness analysis can be used to determine the most cost effective compliance plan to meet local regulations facing a typical refinery. COST EFFECTIVENESS One of the most commonly used methods for quantifying the cost of N O x reduction is "cost effectiveness2". Cost effectiveness is defined as the total dollars spent for a technology in a particular application, per unit of N O x reduced. Cost effectiveness can be calculated using the following equation: Cost Effectiveness = (Capital + Operating + Maintenance) Cost/NOx Reduced Where; Capital = Total installed cost of technology amortized over the expected life of the project ($/yr) Operating = Operating cost of system with new equipment ($/yr) 1 Croce, Patel, Sahu: "Control of Nitrogen Oxide Emissions in Gas-Fired Heaters - The Retrofit Experience", Presented at the, Joint AFRC/JFRC Conference, October 7-10, 1991. 2 Battelle Columbus Laboratories, "The Economic Impact of Environmental Regulations on the Petroleum Industry-Phase II Study", for American Petroleum Institute, June 11, 1976 KTl CORPORATION, CONCORD THE REAL COST OF NOx EMISSION REDUCTION AFRC/JFRC 1998 SYMPOSIUM