Desalinated Water Transmission Pipes: Dependence upon Water Chemistry

Abstract Seawater desalination industry of Saudi Arabia is undergoing an expansion and modernization program to construct more efficient and larger desalination plants which will reduce production and corrosion costs, and CO2 emissions as well. To achieve these goals, a shift from thermal to Sea Water Reverse Osmosis (SWRO) process is taking place. However, during this process integrity of the Cement Mortar Lining (CML) of the transmission pipes are damaged due to changes in water chemistry and chemical treatments of the produced water. The ability of CML to protect iron pipes against corrosion over a timeframe is known, however little knowledge exists regarding the precise parameters that affect the longevity of CML and their ability to prevent underlying corrosion. This paper deals with the water chemistry parameters on which integrity of the CML depends. Criticality of Langelier Index (LSI) and Calcium Carbonate Precipitation Potential (CCPP) for protection of the CML from the corrosive attack of SWRO produced water has been highlighted and few case histories of CML transmission lines due to increase in chloride ion and Total Dissolved Solids (TDS) in the produced water have been presented.