Study for the reconfiguration of cooling water networks in retrofit scenarios

Abstract

"Conventional cooling water systems are typically based on once-though usage of cooling water for each cooler. Cooling water between coolers can be re-used, which allows reducing overall cooling water flowrate at the increased cooling water return temperature (Kim and Smith, 2001). This reuse concept for cooling water can provide new debottlenecking options by effectively utilizing existing cooling tower. However, care must be taken for the implementation of cooling water reuse in retrofit scenarios, as temperature difference between process streams and reused cooling water is likely to be decreased and hence feasibility of heat transfer for coolers may not be sustained. This study investigates impacts resulted from the reconfiguration of cooling water network when cooling water reuse is introduced for debottlenecking of existing cooling water systems. Conceptual design guidelines are provided to regain driving force of heat transfer for coolers by increasing cooling water flowrate for the cooler. Case study is given to illustrate how cooling water network should be reconfigured for retrofit cases in which overall cooling water flowrate is considerably reduced without compensating performance of coolers.