Performance comparison of the main desalination processes: Case studies for small capacity seawater desalting plants

Abstract

The implementation of reverse osmosis (RO) technology in PLN is noticeably increased than multi-effect distillation (MED) and multi-stage flash (MSF). Today, RO has about 39 percent of the design total capacity of plants, while the rest is MSF and MED represent respectively, 31 percent and 30 percent of the total installed desalination capacity in PLN. This paper is concerning the performance evaluation of small capacity desalination units (≤ 50 m3/h), which is the most widely used capacity in PLN. These desalination units have been evaluated for its capacity factor, availability factor, plant capacity factor, GOR and other parameters related to performance have been examined too. It is found that with around 10 years of operation, MSF and MED units are operating below their designed capacity with average plant factor ranging from 0.70 to 0.75 for six months. GOR is found to be lower than designed values. Low-performance ratios are the result of high steam consumption and low production rates of distillate water. With around 2 years of operation, the RO unit is operating slightly below than the designed value. Low-performance ratios are the result of the decreasing production rates of product water and the low quality of product water. In this study, power consumption is examined too. The power consumption of MSF is greater than the electrical energy consumed by MED and RO.