Danfoss launches the world’s first active ERD for medium & large SWRDanfoss launches the world’s first active ERD for medium & large SWRO plants
Until now, isobaric ERDs for large and medium SWRO plants have been passive: their rotating pressure exchangers have been driven only by pressurized water flow. While passive ERDs exchange pressure efficiently, rotor spin controlled only by water flow presents operators with several problems. One is overspin, which occurs when passive ERDs operate above their maximum flow rates and can cause rotors to break apart.
Another is salinity increases due to mixing: to prevent overspin, operators of passive ERDs must avoid overflushing, which would otherwise reduce the salinity increase due to mixing. The resultant higher feed flow salinity lifts the plant’s energy consumption and reduces membrane life.
Danfoss’s active ERD eliminates the problems caused by passive ERDs
Danfoss’s new, active isobaric ERD was developed in close collaboration with the SWRO industry to solve the problems caused by passive ERDs.
“The MPE 70’s motor controls rotor rotation to eliminate any risk of overspin,” explains Michael Bjorn, head of Danfoss’s High Pressure Pumps division. “For the first time, ERDs in medium and large plants can now operate at their maximum flow rates with complete safety and reduce salinity increases due to mixing even when overflushing. Motorization not only reduces the need for ERD redundancy, which in large plants can add up, but also improves larger SWRO plants’ energy efficiency. Furthermore, it has significant benefits for plant reliability and maintenance.
Ready for automation and predictive maintenance
An additional benefit of Danfoss’s new active ERD is its readiness for automation and predictive maintenance.
“The MPE 70 is the first ERD designed for larger SWRO plants that is ready for automation and predictive maintenance,” says sales director Jesper Bentzen. “Owners and operators of large SWRO plants are increasingly turning to these smart solutions to improve reliability and reduce operating expenses.
Innovation that builds on a proven desalination track record
Danfoss has served the desalination industry with innovative high-pressure pump and ERD solutions for decades. The MPE 70 now puts an energy recovery solution proven in small and medium-sized plants at the service of owners and operators of the world’s biggest desalination plants.
“As a thirsty world deals with climate change and CO2 emissions, the focus on reliable energy efficiency for SWRO has never been greater,” says Michael Bjorn. “We believe the advantages of active ERDs are a game- changer for the large-scale plants that already now provide many communities worldwide with their drinking water, and will be even more important in the future.”