Comprehensive analysis of energy saving and high-quality permeate production strategies for a large-scale seawater reverse osmosis desalination plant with diverse process configurations and external resource utilization

Abstract

Seawater reverse osmosis (SWRO) desalination systems require significantly more energy in actual operation compared to the theoretical minimum. By fundamentally understanding and analyzing the energy consumption of SWRO processes, the high energy consumption can be efficiently reduced by adjusting feed water properties using external resources or by optimizing plant design and operation. This study analyzes the performance of full-scale single-pass, two-pass, partial two-pass, and split partial second-pass reverse osmosis (RO) configurations using mathematical models and proposes methods to reduce energy consumption. In addition, it compares strategies to reduce energy consumption in two-pass RO configurations by optimizing the ratio of pressure vessels between stages and the recovery rate conditions between the first and second passes. Furthermore, the study evaluates the potential of utilizing external resources such as power plant thermal discharge and brackish water to alleviate the energy burden of the SWRO process. The research was conducted on a 100,000 m3/day capacity SWRO desalination system, focusing on process performance analysis and energy consumption reduction.