Design alternatives for the use of cooling water in the process industry: Minimization of the environmental impact from cooling systems

In many industrial petrochemical and chemical facilities, surface water is used for cooling purposes. The discharge of cooling water has a considerable impact on the environment. The effects are caused by the emission of heat, discharge of conditioning chemicals and contamination with chemicals from the process. These effects have an adverse impact on the quality of the receiving surface water. A study is presented in which six alternative cooling systems were evaluated for a new oil refinery: once-through, once-through (closed loop), recirculating with cooling tower, recirculating with cooling tower (closed loop), direct air-cooled and air-cooled with closed loop. The main objective was to determine alternative cooling systems with low environmental impact. The study included capital and operating cost estimates, technical feasibility, application as well as emissions to the environment, energy consumption and noise. The study indicated that a direct air cooled system is an interesting and feasible alternative for a once-through cooling water system, resulting in a reduction of the total environmental impact.