The seawater cooling system in Jubail is a vital utility service, which provides uninterrupted supply of seawater for non-contact process cooling to the primary industries of the Jubail Industrial City.
The seawater cooling facility consists of two adjacently located pumping stations near the seashore and a distribution canal connected to the customers through numerous underground lateral pipes. Seawater pumped into the distribution canal flows by gravity to the customers and the return water flows by gravity back to the sea.
Seawater drawn from the Arabian Gulf through dredged intake channels passes through coarse trash screens and fine trash screens at the pump stations and is chlorinated before it is pumped into the distribution canal.
The two pumping stations have fourteen pumps installed in each. The total installed capacity of the pumping stations is 346 cubic meters per second (29.9 million cubic meters per day).
Chlorination plants attached to the two pump stations generate Sodium Hypochlorite, which is used for disinfecting the seawater pumped into the canal by continuous dosing and shock dosing in order to control marine fouling.
Seawater from the pump stations is conveyed to the customers through the canal system, which is about twelve kilometers long, stretching from east west and north south within the industrial city. The canals are generally trapezoidal in cross section, and divided into three compartments by vertical concrete walls. The north and east compartments are only for supply and the south and west compartments are only for return flow. The middle one is normally used as an additional supply compartment but can be used for return flow if required.
The on-shore canal has four sections (Canal 1, 2, 3S and 3N) interconnected by inverted siphons. Seawater is supplied to the customers and returned to the canals through underground concrete/FRP lateral pipes starting from dedicated off take/return structures located along the vertical dividing walls of the canal. Sluice gates installed at these structures provide the flexibility to connect the lateral pipes to either of the adjacent compartments.
Return water is discharged to the harbor through another set of inverted siphons, on-shore discharge channels, the outfall and a dredged discharge channel.
The seawater intake and discharge are separated by the causeway to the Industrial port, which serves as a barrier between the two and eliminates the possibility of recirculation.
The pumping stations and distribution facilities are connected to the Central Control Room through DCS and SCADA system.
The pumping stations and distribution system are provided with Cathodic protection to minimize corrosion.
SEC provides power supply for the pumping stations through two sets of 115 KV feeder lines, each capable of taking the full load.
The seawater cooling facility is extended to the new industrial city Jubail 2, by a pump station at the west end of canal 2 and through a network of pressurized pipes.