عنوان مقاله [English]
The wet cooling towers are one of the main consumers of water in oil and gas refineries as well as petrochemical companies for producing cooling water. If an optimum selection of cooling systems is considered in the design phase and retrofit operations in a factory, considerable water consumption savings will be achieved. For modifying existing systems to determine the best optimal option among all the alternatives available, the mathematical modeling and optimization of such plans can replace expensive laboratory or pilot plant methods previously used. In this study, using the mixed integer linear programming along with the operational experiences of the first superstructure plan, a network of cooling towers was created. In the next step, the most favorable model is regarded in two scenarios to reduce raw water consumption and cooling tower blowdown production with producing demine water (DM) required by the factory. The optimum scenario results in producing 200 m3h-1 DM water and reducing 480 m3h-1 cooling tower blowdown and 200m3h-1 raw water consumption. This scenario results are confirmed and it is now installed in ammonia plant (unit 1). The functions of NPV, IRR, and Payback are used to determine the economic criteria of the plan.