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Show EFFECT OF SOOT ON NOx EMISSIONS IN AN OIL FIRED INDUSTRIAL GLASS MELTING FURNACE Dinesh Gera,1 Dong-Hee Kim,2 and Mridul Gautam2 'Fluent Inc, 3647 Collins Ferry Road, Morgantown, W V 26505 2MAE Department, West Virginia University, Morgantown, W V 26506 This study examines the effect of soot concentration on NOx emissions in an oil fired industrial glass furnace. The combustion process is modeled using a single mixture-fraction, chemical equilibrium, probability density function (PDF) approach in FLUENT5.0. The generation of radical nuclei and formation of soot on these nuclei are incorporated using the two-step Tesner model. It is well known that the presence of soot in the flame increases the radiative heat transfer to the glass and furnace walls due to its luminosity, and also results in reduced peak flame temperature. It is estimated from the current simulation that a peak soot concentration of 1 g/m3 decreases the flame temperature from 2094°C (at Og/m3 soot concentration) to 1726°C. A reduction in peak temperature in turn reduces N O x concentration from 3300 ppmdv to 606 ppmdv at the furnace exit. The numerical simulations are also validated with the existing experimental data available in the literature. 1.0 INTRODUCTION Over the years, technical development and growth of scientific understanding has greatly accelerated in virtually all branches of glass technology. The computer simulation of glass melting furnaces is gaining popularity to accurately model the inter-dependence of certain technically related areas, such as refractories, soot, heat technology, combustion, firing and flow theory on fuel utilization and pollutant emissions. The purpose of this article is to evaluate the effect of soot concentration on N O x emissions in an oil-fired industrial glass furnace. The production of soot in glass melting furnaces is of considerable practical interest because it enhances the luminosity of the flame and hence the radiative heat transfer to the glass. In industrial furnaces, radiation is the primary m o d e of energy transfer. Increased flame radiation increases the efficiency of energy transfer to the objects in the furnace, and hence it increases the furnace productivity. Care should be taken in designing burners, however, in such a way that the soot must be burned or oxidized completely before leaving the flame zone and thereby not increasing the particulate emission levels in the exhaust. The other advantage of this method is that it reduces the combustion gas temperature, and as a result reduces the N O x production rate. Due to the stiff competition and stringent regulations in the glass industry, fuel efficiency and ecology have become a major concern. The industries are concerned with a potential future conflict between the need to conserve energy and the need to protect the environment. M a n y thermally efficient practices are the mechanisms for generating pollutants like N O x and particulates. High temperatures promote efficient heat transfer, but they also generate higher levels of N O v The furnace design as involved in ecology should keep an optimum balance between the capital investment and the amount of pollution generated per process unit from the furnace operation. |