Water. Desalination + reuse
Issue link: https://fhpublishing.uberflip.com/i/107986
PROJECTS The multi-stage flash seawater desalination plant at Shuweihat S2 Phase 3 independent water and power plant in Saudi Arabia had been the largest. However, Shuweihat S2's MSF unit capacity record will soon be replaced by the 20 MIGD (91,000 m³/d) evaporators currently being installed at the Ras Al Khair Phase 1 desalination plant, which is expected to go online in 2014. The Shuaibah and Ras Al Khair desalination plants are also Doosan projects. Advantages of large scale Such large-scale desalination evaporators, designed and fabricated by Doosan, feature three main advantages: 1) Reduced cost With larger evaporators, the required number of units is reduced, and this reduction leads to less civil and common works as well as vendor items, thus lowering the overall project cost. 2) Efficient operation and maintenance With less evaporators, it becomes more convenient and efficient for the owner and/or operator to run and manage the plant. 3) Increased performance A larger evaporator features more flashing stages within the unit, and this leads to higher performance ratio figures. Doosan applies its well-known "One-Module Manufacturing Method" to its evaporator production, which ends with shipping out a completely fabricated evaporator assembled at Doosan's global manufacturing plants in Vietnam and Korea. It took the Shuweihat S2 plant evaporators 45 days to be shipped to the site from Doosan's in-house piers. "One-Module Manufacturing Method" helps prevent any possible production and quality issues that may arise with on-site fabrication, which normally takes place at windy and dusty sites. The method is also known for reducing the unit delivery timeline by five months on average and provides the benefit of less assembly works on site. Plant highlights The Shuweihat S2 desalination plant was the largest plant to go online in 2011, and its seamless delivery and smooth operation helped Doosan win in the Desalination Company of the Year category at the 2012 Global Water Awards. 1) Minimum auxiliary power consumption By optimizing its design and operation concept, the plant currently features the lowest auxiliary load consumption among all MSF plants, at less than 3.9 kWh/m3, underlining Doosan's position in the MSF market. 2) Optimum design & operation of seawater intake pumping station The intake pumping station features reliable redundancy of seawater supply with the aid of common stand-by pumps (power and water) and by-pass valves with an optimized operating concept. 3) Verification by local authority Total dissolved solids vs. conductivity of potable water has been verified by the local regulatory authority, and the plant is successfully running on minimized NaOH consumption. Operation and maintenance (O&M) The scope of the plant's operation and maintenance falls under a 25-year contract with S2 O&M Company, and a total of 100 engineers have been assigned to the project, with fluctuations in number for special cases, such as shutdowns. From the viewpoint of the O&M company, there has been no loss of revenue (and thus no penalty), no emergency shutdown and outage, and, most importantly, the plant has been meeting the full water demands of the offtaker, Abu Dhabi Water & Electricity Authority. The company is believed to have made extra profits thanks to the smooth operation of the desalination plant, which also could have potentially reduced labor/technician costs. The developer GDF Suez is fully satisfied with the overall performance of the plant, citing the following reasons: 1) High performance ratio of 9.8~9.96 2) Ideal tube/chamber conditions leading to sound vacuum formation 3) No technical issues with the ball cleaning system, remineralisation plant, and pumps 4) No common MSF issues, such as tube leakage 5) No technical issues found through the item overhaul check during annual shutdown. It has been stated that the Shuweihat S2 desalination plant is a very smoothly run project due to the know-how and dedication of the Doosan staff as well as the S2 O&M Company. l February-March 2013 | Desalination & Water Reuse | 21 |