Yanbu Phase 2 MED Seawater Desalination Plant Expansion, Saudi Arabia
Yanbu Phase 2 Expansion MED Seawater Desalination Plant, located at Yanbu Industrial City, 300km north of Jeddah, involved installation of a multiple-effect distillation (MED) desalination unit capable of producing 15 million imperial gallons per day (MIGD) / 68,190m³ per day.
The project was carried out in conjunction with an associated power project, which involved installation of three power generation units with a combined output of 690MW at the Yanbu Power and Desalination Plant.
The construction works of the MED desalination plant's expansion commenced in June 2011 and were concluded in December 2012.
The new plant will meet the water supply requirements of more than 200,000 people in the Medina region. The project created about 500 construction jobs for the local Saudis.
The EPC contract for the project was awarded to Hanwha Engineering & Construction, and desalination facilities were supplied by Doosan Heavy Industries & Construction. The facility is owned by Power and Water Utility Company for Jubail and Yanbu (Marafiq).
The project management contract (PMC) services were provided by Jacobs Engineering. The services included project management, quality and safety assurances, permitting support, engineering review, construction supervision, start-up and commissioning. The contract value was estimated to be more than $1bn.
Yanbu desalination plant details
Yanbu desalination plant, prior to the latest expansion project, had a production capacity of 146,160m³ per day.
The plant formerly incorporated a hybrid configuration comprising of nine multistage flash distillation (MSF) units and two reverse osmosis (RO) plants. The MSF units produce steam using heat recovered from the gas turbine power generators for the distillation process. The steam is condensed into fresh water.
Ancillary equipment for the plant includes three potable water storage tanks and three process water tanks, each with a capacity of 40,000m³.
The feed water for the desalination plant is sourced from the Red Sea. The water is conveyed for distribution via 510km of underground piping passing through several pumping stations.
MED desalination plant phase two expansion
The expansion project also included construction and improvements to the marine, sea water network and fuel facilities, along with the installation of the MED facility.
The new ancillary facilities constructed as part of the expansion project included a seawater intake facility and associated pumping station, access tunnel, seawater discharge channel and outfall, control building, electrical building, chlorination plant and pump house, workshop and associated utilities. New roads and fencing works were also set up.
Multiple-effect distillation technology
The technology makes use of several stages (effects) where feed water is heated by steam in tubes during each stage. Some of the water evaporates and flows into the tubes of the next stage, heating and evaporating more water.
Seawater is consecutively introduced into each stage of decreasing pressure, which serves to consecutively lower the temperature required to bring the water to boil. Boiling is mostly achieved on heat transfer surfaces (tube bundles) rather than by flash evaporation used in the MSF process.
A separate condenser is used for condensing the distillate vapour generated in the last stage, which also enables the feed seawater to be slightly pre-heated, decreasing the required heat input. Condensed distillate from each stage is collected in a header tank and transported for post-treatment.
The MED process uses the thermal output of the power plant to heat and evaporate sea water at a low temperature (60°C to 70°C)
The technology consumes three times less power than other thermal processes. The process also requires minimal pre-treatment compared to RO.
Contractors involved with the Saudi Arabian project
The complete civil and building works for the project were carried out by Assad Said, while the design of the civil and structural works was provided by Hiteco Engineering.
Saudi Archiredon was also involved in carrying out the civil, mechanical and electrical works for the major facilities associated with the plant, under a contract worth $210.6m.
Bernard Controls supplied valves and its patented INTELLI+ ST and STX electric actuators, respectively to create weatherproof and explosion proof environments.
In January 2008, Bahrain-based Energy Central Company (ECC) was awarded a 25-year contract to design, build and operate a seawater desalination plant to serve the irrigation needs of the entire Durrat Al Bahrain development.
Saline Water Conversion Corporation's (SWCC) Ras Al Khair Desalination Plant (formerly Ras Az Zawr Desalination Plant) is a hybrid desalination plant which will implement both the multistage flashing (MSF) and reverse osmosis (RO) technologies. The plant is located in the Ras Al Khair Industrial City about 75km north-west of Jubail.