Isobaric Energy Recovery Devices in Reverse and Forward Osmosis ProcessesRichard L. Stover, Ph.D.
OUTLINE
• Energy recovery in seawater reverse osmosis• ERD development milestones• Currently available devices• Design challenges• Next generation devices• New applications
Performance analysis in companion presentation by Dr. Bill Andrews
Energy Recovery in Seawater Desalination
Positive Displacement (isobaric)
Centrifugal (turbine)
Source: Energy Recovery, Inc.
ERD Development Milestones
• First isobaric device – Cheng filed 1965
• Rotary isobaric device – Hashemi filed 1966
• Large chamber device for SWRO – Taylor filed 1973
• RO-isobaric device for lifeboats – Keefer filed 1978
• Pressure exchanger device – Hauge filed 1987
• Ionics Dyprex – late-1980s
• Spool valve for work exchanger – Shumway filed 1996
• Integrated Pump-ERD “Clark Pump” - Permar filed 1996
Currently Available Devices
KSB Saltec
Vari-RO IPER
AquaLyngRecuperator
Spectra Clark pump
Flowserve DWEER ERI
PX
Danfoss iSave
How an Isobaric Energy Recovery Device Works
Low PressureSeawater
Enters the Plant
High PressurePump
High PressureSeawater
High Pressure
Low PressureReject Stream
Low Pressure Fresh WaterExits the Plant
High PressureReject Stream
Booster Pump
Seawater
Membrane
Turbine /Generator
Membranes
High Pressure Pump
Fresh Water
Salt WaterDilute Water
Pressure Exchanger Applications
Basic Osmotic Power
Pressure Exchanger Applications
PX Device
Turbine /Generator
Membranes
CirculationPump
Fresh Water
Salt WaterDilute Water
Efficient Osmotic Power
Pressure Exchanger Applications
PX Device
Membranes
CirculationPump
High Pressure
Pump
Fresh Water
Salt Water
Concentrated Salt Water
Reverse Osmosis Desalination
Design Challenges
• High-pressure seal– leakage and integrity
• Brine-feedwater barrier• Pulsations / vibration
– endured and transmitted• Noise• Operational control
– process transients and multi-device arrays• Unit capacity• Corrosion• Capital costs and maintenance
Next Generation Devices
• ERI PX Titan and PX-300 devices– bigger
Sources: Energy Recovery, Inc. and EPO
Next Generation Devices
• Flowserve/Calder ROVA– smoother
Sources: WDR and EPO
New Applications
Source: Energy Recovery, Inc.
New Applications
Source: Energy Recovery, Inc.
New Applications
Source: Energy Recovery, Inc.
New Applications
Source: Energy Recovery, Inc.
New Applications
Source: Energy Recovery, Inc.
Isobaric ERD
Turbine /Generator
Membranes
CirculationPump
Fresh Water
Salt Water Dilute Water
• Osmotic Power
New Applications
Source: Energy Recovery, Inc.
• Osmotic Heat Engine
Isobaric ERD
Turbine /Generator
FO MembranesCirc.Pump
Working Fluid
Draw Solution
Dilute Water
Regenerator
Q in
Q out
Thank you!
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