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 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 arrays of 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 (29.9million 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 KM long, stretching
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 emanating 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.
Power supply for the pumping stations is provided by SEC through two
sets of 115 KV feeder lines, each capable of taking the full load.
The seawater cooling facility will be extended to the new industrial
city Jubail 2, by constructing a pump station at the west end of
Canal 2 and through a network of pressurized pipes.