Pressure exchanger
A pressure exchanger transfers pressure energy from a high pressure fluid stream to a low pressure fluid stream. Many industrial processes operate at elevated pressures and have high pressure waste streams. One way of providing a high pressure fluid to such a process is to transfer the waste pressure to a low pressure stream using a pressure exchanger.
One particularly efficient type of pressure exchanger is a rotary pressure exchanger. This device uses a cylindrical rotor with longitudinal ducts parallel to its rotational axis. The rotor spins inside a sleeve between two end covers. Pressure energy is transferred directly from the high pressure stream to the low pressure stream in the ducts of the rotor. Some fluid that remains in the ducts serves as a barrier that inhibits mixing between the streams.. The ducts of the rotor charge and discharge as the pressure transfer process repeats itself.
Reverse Osmosis with Pressure Exchangers One application in which pressure exchangers are widely used is reverse osmosis (RO). In an RO system, pressure exchangers are used as energy recovery devices (ERD).High pressure membrane concentrate from the membranes is directed to the ERD. Pressure transfers from the high pressure concentrate stream to a low pressure feed water stream. Pressurized feed water flows from the ERD, driven by a circulation pump. This stream merges with the output of a high pressure pump to form the membrane feed stream [E]. The concentrate leaves the ERD at low pressure, expelled by the incoming feed water flow.
Pressure exchangers save energy in these systems by reducing the load on the high pressure pump. In the pressure exchanger the energy contained in the brine is transferred hydraulically and with an efficiency of approximately 98% to the feed. This reduces the energy demand for the desalination process significantly and thus the operating costs.
A pressure exchanger transfers pressure energy from a high pressure fluid stream to a low pressure fluid stream. Many industrial processes operate at elevated pressures and have high pressure waste streams. One way of providing a high pressure fluid to such a process is to transfer the waste pressure to a low pressure stream using a pressure exchanger.
One particularly efficient type of pressure exchanger is a rotary pressure exchanger. This device uses a cylindrical rotor with longitudinal ducts parallel to its rotational axis. The rotor spins inside a sleeve between two end covers. Pressure energy is transferred directly from the high pressure stream to the low pressure stream in the ducts of the rotor. Some fluid that remains in the ducts serves as a barrier that inhibits mixing between the streams.. The ducts of the rotor charge and discharge as the pressure transfer process repeats itself.
Reverse Osmosis with Pressure Exchangers One application in which pressure exchangers are widely used is reverse osmosis (RO). In an RO system, pressure exchangers are used as energy recovery devices (ERD).High pressure membrane concentrate from the membranes is directed to the ERD. Pressure transfers from the high pressure concentrate stream to a low pressure feed water stream. Pressurized feed water flows from the ERD, driven by a circulation pump. This stream merges with the output of a high pressure pump to form the membrane feed stream [E]. The concentrate leaves the ERD at low pressure, expelled by the incoming feed water flow.
Pressure exchangers save energy in these systems by reducing the load on the high pressure pump. In the pressure exchanger the energy contained in the brine is transferred hydraulically and with an efficiency of approximately 98% to the feed. This reduces the energy demand for the desalination process significantly and thus the operating costs.
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