Process modelling in desalination plant operations

Operation of desalination process is sometimes a difficult task, especially when the plant is getting older. Process engineers and operators are required to follow-up any changes or variations in process parameters either in control room or on-site measurements. Undetectable deviation and/or malfunctioning in any of measurement devices could occur specially during long-time successful operation without major shutdown for the entire plant or when the process is part of very complex integrated processes in an industrial site. This deviation, inaccurate-reading or malfunctioning values can be due to un-calibrated devices (i.e. flow-meters) or fouling of measurement devices (i.e. thermo-couples). Practically, process modelling is a useful tool that can assure and confirm that the process measurements parameters are accurate. Incorrect balancing of mass and/or energy can be detected easily as well as the productivity of the plant. In this paper, multi stage flash (MSF) desalination plant was illustrated and evaluated. Malfunction of measurement device showed the plant was producing distillate more than what was really measured or received by down stream processes. Excel spreadsheets was developed and utilized for process modelling and confirming the results.