Desalinated Water Transmission Pipes: Dependence Upon Water Chemistry

Paper ID: C2025-00049 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 emission as well. To achieve these goals, a shift from thermal to seawater 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 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 presents case histories of CML transmission lines due to increase in Chloride ion and total dissolved solids (TDS) in the produced water. Also, a concept to develop a prediction software in the form of a model for determining the range of treated water chemistry for safe water transmission through cement lined pipelines is discussed. This software may provide an accurate estimation of the Langelier Index and Calcium Carbonate Precipitation Potential (CCPP) for protection of the CML from the corrosive attack of SWRO produced water.