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3.1 Reheat Solar Collector Cycle (RSCC) :

The cycle happened as follows: We will take the brine water from the last stage of
distillation then brine water pumped to solar collectors. Solar collector will raise the
temperature of brine water to flush point and then the hot brine will enter flash
stages. The hot brine water will evaporate instantly due to pressure drop in the vessel,
the steam produced will heat exchange with income seawater so the steam condenses
and then collects in the freshwater tank.

3.2 Mathematical study for RSCC:

To test the efficiency of RSCC, we conducted a study Al-Khafji MSF desalination
plant, located in Saudi Arabia (KSA). The plant contains 20 stages at the capacity
of 600,000 gallons per day( 2271.25 cubic meters per day ).[11]

Data of Al-Khafji MSF desalination plant :

T in 20° c

TDS in 35000ppm

m ̇ in 2.5 Mkg/hr

The pressure of the 1 stage 0.6 bar g
st

The pressure of the last stage 0.1 bar g

T enter 1 stage 110° c
st
T out last stage 41° c

TDS out 73000ppm

m ̇ out 2.3 Mkg/hr

Total ṁ steam 0.184 Mkg/hr

GOR 7.8

Steam used in boiler 23589 kg/hr

Table 3.1 data for Al-Khafji plant
Gain Output Ratio (GOR) is used to compute energy efficiency for MSF plants.
The higher the GOR value is the better is the performance plant.

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