Process Integration and System Analysis for Seawater Cooling in Industrial Facilities

Abstract

Using seawater in cooling systems is a common practice in many parts of the world where there is a shortage of freshwater. Biofouling is one of the major problems associated with the usage of seawater in cooling systems. Microfouling is caused by the activities of microorganisms, such as bacteria and algae, creating a very thin layer sticks to the inside surface of the heat exchangers. In some instances 250 micrometer thickness of fouling film would reduce 50% of the heat exchanger heat transfer coefficient. On the other hand, macrofouling is the blockage of marine relatively large organisms, such as oysters, mussels, clams, and barnacles. Therefore, a biocide is typically added to eliminate or at least reduce microfouling by intermitted dosages and macrofouling by continuous dosages. The objective of this work is to develop a systematic approach to the optimal design and integration of seawater cooling system. Specifically, the paper will address the following tasks:

1. Identification of the reaction pathways for the biocide from the mixing basin to the discharge points

2. Kinetic modeling of the biocide and byproducts throughout the process

3. Process integration for the reduction of biocide usage and discharge.