A Practical Tools for Targeting and Design of Cooling Water Networks

Abstract

Recirculating cooling water networks (CWN) consists of three main components: heat exchanger networks (HEN), recirculation system and cooling tower (CT). In current practice, the cooling water (CW) is circulated without reuse via HEN in parallel configuration to provide cooling duties for hot process streams and returns to CT with high flow rate and low temperature. Therefore, there is a decrease in the performance of the CT.In this paper, the Demand-Composite Analysis (DCA) based on Pinch technology is developed for CW reuse and to address energy efficiency issues in CWN for retrofit design problem. This technique is an analytical approach requiring no graphical procedures can targets simultaneously, prior the detailed network design, the minimum flow rate and maximum temperature of waste cooling water (WCW) from HEN to CT. Under these conditions, the effectiveness of CT becomes high and CT that eliminates more heat.The application of DCA requires that cooling requirements be converted to their equivalent in terms of sources and demands The Demand-Composite Curve (DCC) is a graphical representation generated from DCA to understand the targeting philosophy. A case study is treated to illustrate the practicability of this approach. For this case, the effectiveness of CT is enhanced from 56.9% to 64.1%.