RF Materials : Desalination

Desalination

Dr R Francis has been involved in corrosion issues with desalination plants for over 25 years, and this has included MSF, MED and SWRO plants. He has been involved with many different components and alloys in various parts of both thermal and reverse osmosis plants. The work has covered a number of different aspects.

External corrosion of 90/10 Cu-Ni tube from the heat recovery section of an MSF plant

Failure Investigations

Dr Francis has looked at failures of heat exchanger tubes from thermal desalination plants, in many different locations. These have covered mostly copper alloys and some of the corrosion problems have been internal, while others have been external. In all cases it has been possible to make recommendations about plant operating conditions and/or practices to prevent a re-occurrence.

Other failures have been with heat exchanger tube sheets, pumps or valves, covering a range of materials of construction. In all cases it has been possible to explain to the plant operator how to avoid future failures.

Failure examinations in SWRO plants have covered piping, pumps, filter vessels and valves. These have all involved duplex stainless steels, with a variety of reasons for the failures.

Materials Advice

Manufacturers of specific equipment, such as pumps, or plant designers have consulted RFMaterials to determine the most suitable materials of construction for parts of desalination plants. In some cases, it has involved reviewing a current material selection strategy and advising what changes might be required. This takes advantage of Dr R Francis’ extensive experience in selecting materials for these applications.

Technical Specifications

In some cases the basic materials standards (such as ASTM) are not sufficient to ensure delivery of material of a quality suitable for long term, reliable service in a desalination plant. Dr R Francis has worked with a number of equipment suppliers and plant designers to write technical procurement specifications, including the requirements for auditing, testing and witnessing. The cost of ensuring the delivery of satisfactory material is much less than the costs associated with a major failure, and possible extended shutdown while repairs are undertaken.