Author Identifier

ORCID: 0000-0002-0214-189X

Date of Award

2019

Document Type

Thesis - ECU Access Only

Publisher

Edith Cowan University

Degree Name

Master of Engineering Science

School

School of Engineering

First Supervisor

Dr Gordon Lucas

Second Supervisor

Associate Professor Guangzhi Sun

Abstract

Water is one of the most important elements in human life. The major sources of water are defined as seawater, which cannot be used in many applications unless it gets desalinated. In this regard, investigations and developments for defining new economical and beneficial technologies in desalination methods have become more significant.

In this research, the influence of wind power fluctuations on Reverse Osmosis (RO) membrane lifetime, in terms of variations in membrane inlet flowrate and/or pressure, was investigated experimentally. The RO membranes applied in this project,were spiral wound module, Model: DOW FILMTEC, SW30- 2521 used individually in the rig for each test.

The experiments were conducted using a modified lab-scale seawater RO unit (CE-530) from GUNT Hamburg company. A variable speed positive displacement pump and two actuated step motor valves were applied in the rig to facilitate the required wind fluctuations.

At the first stage of this research, some initial experiments were accomplished to find the basic requirements of the fluctuating tests. Afterwards, three series of experiments were conducted each on an individual s new membrane to analyze the effect of fluctuating flowrate and/or pressure on their lifespan. A sample wind fluctuating pattern was followed in all three sets of tests. Based on the requirements of each test, three remote-control system were programmed using LABVIEW software, each used for the specified test. Each test was performed for 7 weeks (5 working days), 4 hours a day (140 hours). Deterioration mechanism of the membranes was monitored by measuring target parameters in two constant flow conditions weekly (after 20 hours of fluctuating operation) for each test. By comparing the results, the influence of flowrate and/or pressure fluctuations on membrane lifespan was evaluated.

Accomplishing the fluctuating experiments, structural deterioration of the membranes was investigated using Scanning Electron Microscope (SEM) tests comparing them with the original structure of a brand new membrane. These results could not give a justifiable conclusion on the membranes deterioration mechanism. Therefore, the conclusion was derived based on the membrane operational monitoring curves.

The results of this research would be significant in reducing costs of a stand-alone wind powered RO desalination process by elimination of intermediate energy storage.

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