DESIGN OF COOLING WATER SYSTEM FOR ATTOCK REFINERY LIMITED

Abstract

Cooling tower is crucial piece of equipment for any refinery as it is used to reject waste heat. It operates on the principle of heat and mass transfer and cools water on the mechanism of evaporation. Cooling water system has a wet-cooling tower which provides cooling water to heat exchangers in parallel. Our project aims to reduce both energy and water consumption by replacing three existing cooling towers with one, along with devising an efficient exchanger network. For the design of the tower Merkel’s Method is used through which an enthalpy –temperature diagram is constructed and used to find the number of stages. Manually designed cooling tower was simulated on Aspen Plus to find out the targeted relative humidity. Packed bed sand filter was used to purify the blowdown stream and centrifugal pumps installed in different streams. For the optimization of heat exchanger networks Aspen Energy analyzer was used which gave the least possible heat transfer area further utilized to calculate the purchase cost of equipment