Patent ID: 8834712
Filing Date: 2014-09-16
Classification: C02F,Y02A

Abstract:
1. A seawater desalination system comprising: a membrane filtering pump which outputs seawater stored in a water obtaining vessel in accordance with a first control signal, the first control signal controlling flow rate of the seawater from the membrane filtering pump; a first flowmeter which measures a first flow rate of the seawater from the membrane filtering pump; a filtering membrane which filters the seawater from the membrane filtering pump; a high-pressure pump which outputs filtered water, that is filtered by the filtering membrane, in accordance with a second control signal, the second control signal controlling flow rate of the filtered water from the high-pressure pump; a first pressure gauge which measures a first pressure of the filtered water from the high-pressure pump; a reverse osmosis membrane which desalinates the filtered water from the high-pressure pump into fresh water; a second flowmeter which measures a second flow rate of the fresh water from the reverse osmosis membrane; a third flowmeter which measures a third flow rate of high-concentration salt water, the high-concentration salt water being discharged when the filtered water is desalinated in the reverse osmosis membrane; a discharge valve which discharges the high-concentration salt water in accordance with a third control signal, the third control signal controlling a valve opening degree of the discharge valve; a control module which performs first flow rate control, second flow rate control, and third flow rate control, the first flow rate control generating the first control signal such that the first flow rate follows a sum of the second flow rate and the third flow rate and supplying the first control signal to the membrane filtering pump, the second flow rate control generating the second control signal such that the second flow rate follows a preset target value, and supplying the second control signal to the high-pressure pump, and the third flow rate control generating the third control signal such that the first pressure falls within a preset pressure range, and supplying the third control signal to the discharge valve; a control valve which outputs the filtered water, that is outputted from the filtering membrane and divided at a diverging point located before the high-pressure pump, in accordance with a fourth control signal, the fourth control signal controlling pressure of the divided filtered water by changing a valve opening degree of the control valve; and a power recovery device which increases the pressure of the filtered water from the control valve by using pressure of the high-concentration salt water, and outputs the filtered water, wherein a water feed pipe from the membrane filtering pump to the filtering membrane and a water feed pipe from the filtering membrane to the high-pressure pump function as header pipes and have a diameter that is larger than a diameter of a water feed pipe preceding the membrane filtering pump and a water feed pipe subsequent to the high-pressure pump.