Experimental study of a booster pump-free isobaric energy recovery device (DAC) for reverse osmosis: Performance evaluation and comparison

Abstract

Reverse osmosis (RO) is a widely used desalination technology known for its high energy requirements. However, the incorporation of energy recovery devices (ERDs) in RO plants has proven effective in reducing specific energy consumption. The booster pump (BP) is an essential component utilized in conjunction with isobaric ERDs. Approximately 5 to 10 % of the capital cost for small to medium-sized RO units is attributed to the BP. The objective of this paper is to investigate the feasibility of implementing a newly designed isobaric ERD called DAC. The study focuses on an RO plant with a capacity of 48 m3/day. The proposed ERD undergoes design, manufacturing, and experimental testing. The major benefit is its ability to utilize the system feed pump as a BP, eliminating the need for a separate BP. This equipment reduction not only lowers the initial cost but also simplifies the system complexity. Furthermore, the system is designed to allow a comparison between the DAC and a pressure exchanger (PX) under the same operating conditions. However, unlike the DAC, the PX becomes unresponsive and does not function when the BP is turned off to allow the system feed pump to take over.