Pig being removed from sea

Desalination technology is vital for many countries where the rainfall or the natural supply of fresh water is insufficient to meet the needs of the population and local industry. Seawater intake pipelines allow sea water to flow to desalination plants where minerals are then removed from the saline water through a desalinisation process. Raw water for the desalination process usually comes from offshore via very large diameter pipelines known as sea water intake pipelines.

These pipelines are often constructed from HDPE with GRP and reinforced concrete sections with no internal lining and are subject to natural fouling from marine growth, such as barnacles and mussels. Cleaning the seawater intake pipeline by pigging is then required as a build up of marine growth will cause a reduced flow of water at the desalination plant. If sea water intake pipeline cleaning is not performed, then it could result in a pipeline blockage or cause the desalination plant to underperform or even force a plant shutdown.

If marine debris is allowed to grow in seawater intake pipelines, it can quickly have an adverse effect on the performance of the pipeline; the friction of the water flowing through the pipeline will increase, which will lead to more turbulent flow and the seawater intake pipeline efficiency can be reduced by 50% or more within a short time frame.

Occasionally divers have been utilised to clean the internal surface of large diameter seawater pipelines, but this is not only laborious, time consuming and expensive, but also a health and safety risk to personnel.

The same problem exists in many Seawater Intake pipelines for facilities such as power plants.


Desalination Technology – How to Clean a Sea Water Intake Pipeline System and a Desalination Pipeline System

desalination technology pig internals

The Pigtek Desalination Pipeline Cleaning Pig is usually configured to operate as a Bi-Di Pig, having a stainless steel steel mandrel pig body fitted with replaceable polyurethane guide discs and seal discs for scraping and sealing within the pipeline. All discs are supplied as one solid piece, rather than utilising overlapping or segmented discs, to maintain the cleaning efficiency of the pig. The cleaning pig is run through the desalination pipeline to remove mussels, limpets and other marine fouling in the pipeline to maintain flow assurance.

Desalination technology often uses very large diameter seawater intake pipelines and Pigtek have delivered pigs for cleaning pipelines up to 2,600mm in diameter. Designs include a number of unique features to aid cleaning efficiency and to assist in the handling and operation of such a large pieces of equipment. Certified lifting points are often fitted and steel pig handling and storage frames supplied.

Pigtek can assist with the design of desalination systems to enable pigging to be performed in seawater intake pipelines.

Pigtek can advise on how pigs can be inserted, launched and recovered and can provide pigging procedures for pipeline cleaning. Pigtek can also provide experienced personnel to assist with on-site operations and give training to operators personnel during initial uses of the pigs.