Suggested modifications of power-desalting plants in Kuwait

Modifications are suggested to the Kuwaiti cogeneration power-desalting plants CPDP. The suggestions would increase their desalting capacity, use more efficient desalting systems, and solve the acute problem of matching the installed desalted water capacity with the ever increasing demands of potable water. In year 2003, 93% of potable water was satisfied by the desalted water. The suggested modifications for a 300 MW steam turbine combined with two MSF units of 6 MIGD each include: (1) Substitute some of the old and in-efficient MSF units with more efficient multi effect desalting MED system of almost the same capacity, and gain ratio. The MED system can use low pressure steam of 75EC saturated temperature as heat source, and about 2 kWh/m3 pumping energy (about 50% less than that of MSF units). (2) Adding a back pressure steam turbine BPST. Steam, now extracted from the steam turbine, at pressures ranging from 4.74 to 3.5 bar to the MSF units, is directed to an added BPST to produce more work before its discharge at 0.4 bar (about 75EC saturation temperature), as needed by the suggested MED units. (3) Adding seawater reverse osmosis SWRO desalting system. The work output from the BPST can be used to operate a seawater reverse osmosis SWRO desalting plant to produce more desalted water. Details of the modification are given in the paper. The modifications increase the power output of the plant without adding any more fuel. It can add up to three times the desalting capacity if SWRO system, and without adding any more fuel.