Sadara, a very large scale petrochemical complex located in Jubail, KSA, has chosen Marafiq, the Water and Power Utility Company for Jubail and Yanbu, to supply Sadara with industrial water of various qualities, mainly for process cooling purpose, through a water supply agreement (BOO). For this purpose, a new RO desalination plant has been built within the premises of the Sadara complex.
In June 2013, Marafiq has awarded to Sidem/VWT an EPC contract for the design, supply , construction and commissioning of the SWRO plant, and a 10 years Operation and Maintenance contract. The project has been commissioned in 2016 and is in commercial operation since December 2016.
One of the challenges was the limited footprint available, for which dedicated solutions were designed: no intermediate tanks were installed between Ultrafiltration plant, first RO pass and second RO pass which was achievable thanks to a performant automation system allowing smooth and easy operation.
An Early Water Period was required by Marafiq during commissioning to supply water to Sadara to support their various construction and commissioning activities of the Complex. The plant is capable of varying its production between 10% and 100% to meet the water demand with very short ramp-up and ramp-down time.
The plant is located on shore some 20 km away from the sea. The seawater is pumped to the plant firstly through an open air channel and then with an intermediate boosting station located several kilometers away feeding the plant with underground pipes. These infrastructures were built by the Royal Commission and are now operated by Marafiq.
The seawater supply and brine discharge piping infrastructure are pressurized. The plant has accordingly been designed with an intermediate seawater open air break tank with a dedicated pumping station for the pre-treatment lines, and with brine break tanks to enable a gravity flow up to the reject some 20 km away.
The pretreatment is provided with Veolia patented high velocity dissolved air floatation SpidflowTM, self-cleaning strainers, and an Ultra Filtration plant supplied by pumps driven by VSD’s feeding directly the RO HP pumps without intermediate break tank.
Two-pass reverse osmosis plant
The first pass SWRO skids are equipped with high efficiency Energy Recovery Devices. In order to meet the stringent permeate quality for Sadara, a full second pass BWRO system is required in the summer. The RO plant is equipped with a fully automated flushing and cleaning-in-place system.
The post-treatment is ensured by saturated lime water and CO2 and the sterilization is made by gas chlorine.. Specific safety detection and protection systems are provided in the dedicated chlorine building. The saturated lime water is prepared using Veolia Multiflo® saturators. Three water qualities are processed by the post-treatment plant, and the Industrial waters are stored in different tanks with their own pumping station.
The source of energy of the plant is provided from Sadara substations, and is stepped down to the various voltage requirement of the plant. A fully automated system is controlling all process areas and is reported to the main control room located on the plot. The plant is interfaced with Sadara’s control systems (fire and gas, process, communication) and is reporting to the Marafiq main control building located off the site 20 km away.
Critical buildings are provided with redundant HVAC and are built with reinforced concrete in order to meet design blast loads required by the vicinity of tank farms with highly inflammable products.
The plant is provided with a comprehensive metering system and invoicing settlement system for invoicing purpose under the supply agreement between Marafiq and Sadara.
The plant is meeting the latest standards of Saudi Arabia Governmental entities such as the Royal Commission Environmental Regulations and the High Commission for Industry Safety.
Redundancies are built in the whole plant to ensure no single point of failure and maintain an availability of exported water of 100%.