A Practical Approach to Pollution Reduction in Isfahan Province Steel Making Plants

IntroductionToday, in addition to environmental effects, air pollution has economical, social and political consequences. Such a problem is more striking in metropolitans where accumulating population, vehicles and industries, altogether produces large amounts of pollution. A discernible example is Isfahan city and province. Isfahan has one of the largest steel-producing facilities in the entire region as well as facilities for producing special alloys. Isfahan contains a major oil refinery and a large aircraft manufacturing plant. Unfortunately, on the other side, this city is one of most polluted cities in Iran. In recent years, this problem turned to be more severe due to climate changes. Consequently, finding clean and efficient solutions to contaminant industries is crucial. It should be noted that among the mentioned industries located in Isfahan, steel making plants play a major role in air pollution. In fact, in every metric ton of steel produced, 10 to 25 kilograms of dust is accumulated. Further, a large portion of exhaust gases of electric arc furnaces (EAF) consists of CO, NOx and Sox, which proved to be a threat to human health and environment. Thus, control and reduction of pollution production in steel making plants is essential. Until now, various clean air solutions to EAFs and fume de-dusting systems, have been developed. Definitely, there is no question that de-dusting systems are crucial. However, the costs and outlay of fume extraction systems operation should be no higher than absolute necessary. To be practical, the most important goals are high efficiency, compliance with prescribed threshold values and low consumption of energy. One reliable and feasible method to ensure the functionality and efficiency of these systems are Computational Fluid Dynamic (CFD) simulations. In such a modeling, the effect of various parameters can be studied, which leads to improved designs and higher efficiencies. Therefore, developing models for de-dusting systems of steel making plants would be a useful practice. Despite several studies in the field of modeling and optimization of fume extraction systems, no one has addressed the problem of turbulent reactive two-phase flow in industrial fume de-dusting systems and investigations are limited to approximate zero or one dimensional thermodynamic solutions. The present study aims to fill this gap in literature. In this paper the Mobarakeh Steel Making Plant is examined and the effect of operating parameters on the overall fume de-dusting system performance and efficiency is investigated.Materials and Methods The mathematical model of processes inside the fume extraction system is constituted of four different parts: swirling turbulent flow, Heat and mass transport by convection, chemical reactions and radiation. Hence, in order to model the problem, five sets of equations should be solved: continuity, momentum, energy (including radiation), species transport and turbulent flow modeling equations (in time averaged form).