In Iran, environmental pollution control has become an important issue in recent years. Accordingly Isfahan Province industries, including the Mobarakeh Steel Co. (MSC), are required to observe stricter emission regulations. Toxic carbon monoxide emissions from exhausts of annealing unit of MSC were higher than allowable limits which were set by environmental protection agency. Hence, it was needed to reduce the quantity and concentration of this toxic emission by conversion to nontoxic gases like carbon dioxide.In industrial processes, oxidation reaction of carbon monoxide and conversion to carbon dioxide is carried out in catalytic fixed bed reactors using hopcalite and platinum catalysts. In this work first, dimensions of a catalytic reactor with either copper oxide or hopcalite catalysts were simulated using the MATLAB software. Then the fixed bed reactor with copper oxide catalyst was built and installed under one of annealing furnaces in the annealing unit of MSC. After two months of operation of the catalytic fixed bed reactor due to many operational problems including blockage of the gas path by condensed oil vapors, and high pressure drop, it was decided to change the reactor type to combustion reactor. As annealing furnace was already available, then this option has better advantages over the catalytic reactor, such as dropping the cost of building the reactor and catalyst purchase and regeneration costs. Other advantages of combustion reactor are dropping of carbon monoxide level to 1 percent of the regulation limit, vanishing of problems that caused by oil vapors in the exhaust ducts, decrease in fuel consumption of annealing furnaces, decrease in heavy hydrocarbons emission, and removal of four large air blowers which are used to dilute the emitted CO concentrations. So with some modifications in the design of an existing furnace, it was used as the furnace reactor. Carbon monoxide concentration in the exhaust of this furnace was decreased to 5 ppm. Key words: carbon monoxide, Mobarakeh Steel, hopcalite, fixed bed reactor, regulation standard
