SEAWATER COOLING WATER SYSTEM DESIGN: BAD PRACTICE, GOOD PRACTICE

摘要

In today’s world more and more aspects of power generation, gas and oil storage and transfer facilities are requiring the use of large quantities of seawater for cooling and processing purposes within the plant operations. Due to the size, location and nature of the overall development of the aforementioned facilities the requirement for the cooling water system is being perceived as a non‐critical part of the overall scheme during the feasibility and design process. The cooling water system usually comprises obtaining sea water at a certain temperature from the source, then transporting this water to the Plant process equipment by means of channels/pipelines to pumping and settling chambers on land. Once the water has been used in the Plant system it then is discharged back to the sea to an environmentally designated depth and location via channels or pipelines. The cost of incorporating a cooling water system may only be 1 ‐ 10% of the overall cost of the Project but the importance of providing a robust designed system that will operate the plant during its design life is key to successful operation. One recent example of providing cooling water to a Power Plant showed clear misunderstanding of the importance of the cooling water system to overall operation of the Plant. In fact the cooling water system was so badly designed that amongst many other problems within 3 months of commissioning the offshore pipelines were blocked by sediments and that due to this the Plant could only operate at 50% of its capacity. The reason for the poor design and construction was due to the fact that the Client appeared not to understand the importance of the Cooling Water System and decided to conduct the design as an afterthought using in house design team who had no experience of such systems. This paper will highlight some of the problems encountered and will demonstrate the need for employing at an early stage of the project experienced engineers from fields of hydraulic, pipeline and mechanical engineering for the successful design and then operation of a Cooling Water System. For the reason of confidentiality the location of the project and the name of the Client cannot be disclosed.