Abstract: An energy recovery system in a seawater desalination plant uses a reverse-osmosis membrane method for removing salinity from seawater. The system is configured to supply high-pressure water produced by pressurizing raw water with a high-pressure pump to a reverse-osmosis membrane cartridge, and to supply concentrated water discharged from the cartridge to an isobaric energy recovery device to recover pressure energy of the concentrated water whereby part of the raw water supplied to the isobaric energy recovery device is pressurized, and then to allow the pressurized raw water to merge into the high-pressure water pressurized by the high-pressure pump. The system includes a booster pump for boosting a pressure of the concentrated water discharged from the cartridge, and an energy recovery turbine for recovering energy by using the pressure head difference between the pressurized raw water from the isobaric energy recovery device and the high-pressure water discharged from the pump.

Abstract: An energy recovery apparatus usable in a seawater desalination system. The energy recovery apparatus includes a plurality of chambers to pressurize the seawater by pressure energy of the concentrated seawater by supply and discharging the concentrated seawater and the seawater, a first flowmeter for integrating a flow rate of the seawater or the concentrated seawater which flows into the chamber, a second flowmeter for integrating a flow rate of the seawater or the concentrated seawater discharged from the chamber, a switching valve in each of the chambers to switch the inflow and the discharge of the concentrated seawater, and a controller to control the respective switching valves of the chambers on the basis of integrated flow rate of the chamber obtained from the flow rate of the flowmeter. The controller inputs a single input signal to the respective switching valves of the chambers to control the respective switching valves.

Abstract: An energy recovery system in a seawater desalination plant uses a reverse-osmosis membrane method for removing salinity from seawater. The system is configured to supply high-pressure water produced by pressurizing raw water with a high-pressure pump to a reverse-osmosis membrane cartridge, and to supply concentrated water discharged from the cartridge to an isobaric energy recovery device to recover pressure energy of the concentrated water whereby part of the raw water supplied to the isobaric energy recovery device is pressurized, and then to allow the pressurized raw water to merge into the high-pressure water pressurized by the high-pressure pump. The system includes a booster pump for boosting a pressure of the concentrated water discharged from the cartridge, and an energy recovery turbine for recovering energy by using the pressure head difference between the pressurized raw water from the isobaric energy recovery device and the high-pressure water discharged from the pump.

Abstract: A seawater desalination system uses a reverse osmosis separation device. According to characteristics of a reverse osmosis membrane, the pressure or flow change rate of seawater is controlled with respect to the membrane at the start and stop of a high-pressure pump. A drive power source control device including a parallel circuit of a reduced voltage starter and a switch is connected between an electric motor for driving the pump and an AC power source. Control of the starter causes an AC voltage supplied to the motor to increase continuously during a start-up adjustment duration to asymptotically approach an AC power source voltage from zero with an upwardly-convex monotonically-increasing function, and to decrease continuously to zero during a stop adjustment duration as far as zero. The switch is closed to supply the AC voltage of the power source directly to the motor when it equals voltage supplied via the starter.

Abstract: An energy recovery apparatus usable in a seawater desalination system. The energy recovery apparatus includes a plurality of chambers to pressurize the seawater by pressure energy of the concentrated seawater by supply and discharging the concentrated seawater and the seawater, a first flowmeter for integrating a flow rate of the seawater or the concentrated seawater which flows into the chamber, a second flowmeter for integrating a flow rate of the seawater or the concentrated seawater discharged from the chamber, a switching valve in each of the chambers to switch the inflow and the discharge of the concentrated seawater, and a controller to control the respective switching valves of the chambers on the basis of integrated flow rate of the chamber obtained from the flow rate of the flowmeter. The controller inputs a single input signal to the respective switching valves of the chambers to control the respective switching valves.

Abstract: A power recovery system is used for reducing the total energy consumption in a process such as an industrial treating process or a fluid refining process including the delivery of a fluid under a high pressure. The power recovery system includes a high-pressure pump for pressuring raw water, a reverse osmosis membrane cartridge for treating high-pressure water discharged from the high-pressure pump with a reverse osmosis membrane to produce treated water, a positive-displacement piston pump for pressuring raw water under the pressure of concentrated water which is discharged from the reverse osmosis membrane cartridge without being treated by the reverse osmosis membrane, and a power recovery pump turbine for boosting the pressurized raw water discharged from the positive-displacement piston pump and adding the boosted water to the high-pressure water discharged from the high-pressure pump. The power recovery pump turbine is actuated by pressurized water generated in the power recovery system.

Abstract: A power recovery system is used for reducing the total energy consumption in a process such as an industrial treating process or a fluid refining process including the delivery of a fluid under a high pressure. The power recovery system includes a high-pressure pump for pressuring raw water, a reverse osmosis membrane cartridge for treating high-pressure water discharged from the high-pressure pump with a reverse osmosis membrane to produce treated water, a positive-displacement piston pump for pressuring raw water under the pressure of concentrated water which is discharged from the reverse osmosis membrane cartridge without being treated by the reverse osmosis membrane, and a power recovery pump turbine for boosting the pressurized raw water discharged from the positive-displacement piston pump and adding the boosted water to the high-pressure water discharged from the high-pressure pump. The power recovery pump turbine is actuated by pressurized water generated in the power recovery system.