Optimization studies of fresh cooling water network in ammonia manufacturing plant

The heat exchanger network system is an important part of the process industry. Closed-loop fresh cooling water heat exchanger network in ammonia manufacturing plant is used for the cooling of process fluids. From commission stage to the present operation stage, the heat loads in various heat exchangers of fresh cooling water network system got varied in the ammonia manufacturing plant. Some heat exchangers were overloaded and some running at sub cooled below the process requirements. An optimization study was carried out on fresh cooling water network system to fix the heat load distribution across the network system. The process-side heat duty was calculated by using the heat of formation for each component at the inlet and outlet of individual heat exchanger. The calculated heat duty values were compared with the values obtained from Aspen HYSYS simulation modeling techniques. The total flow required through the whole network can be reduced by 3000 m3/h without affecting the production of the plant and approximately $ 65000-130000 can be saved per year.