WEG, a leading international company in electrical and mechanical solutions for the water sector, and Aqualia, a leading water management company in the market, are to collaborate on an R&D project for energy recovery in desalination plants. The project aims to provide new systems for regulating reverse osmosis racks for brackish water to make them amortizable in the short term and achieve greater environmental sustainability.
Historically, energy recovery in small desalination plants was not profitable, as the flow and pressure are small, so the energy potential is very moderate. Therefore, this project uses a low-cost, high-efficiency turbogenerator to recover energy from salt rejection in brackish water reverse osmosis racks, replacing the traditional back-pressure valve that regulates the system.
To meet this objective, WEG and Aqualia have joined their knowledge and efforts in the development of this system, which, although it already exists commercially on the market, provides a different vision of how to manufacture it based on simple commercial equipment such as inverter centrifugal pumps, inverter motors, and regenerative electronic frequency inverters.
This project will involve a pilot plant with four brackish water desalination lines with a unit production of 5,000 m3/day per line, operating with a conversion factor of 75%. WEG will participate by providing energy recovery equipment such as permanent magnet synchronous motors in reverse rotation and regenerative electronic frequency inverters.
The project aims to provide new systems for regulating reverse osmosis racks for brackish water to make them amortizable in the short term and achieve greater environmental sustainability
After several months of theoretical analysis, the results are positive, and it has been concluded that the implementation of turbogenerators based on an inverter pump, plus a synchronous generator and regenerative frequency inverter is a viable option for energy recovery from the reject line where the concentrate leaves a brackish water reverse osmosis frame. This means a more significant environmental commitment, reducing the carbon footprint, recovering energy in electrical form, and, therefore, a reduction in the electrical consumption of the desalination plants and an economic amortization of the installations.
After this first theoretical development of the project, work is being carried out on implementing a full-scale pilot project to validate the system and incorporate it in other existing or newly built plants.
This project was presented at the 13th AEDyR International Congress and was very well received by the desalination and reuse community. José Luis Marín Delgado, Aqualia’s Project Engineer, and Jesús Rivas Moro, WEG’s Water & Wastewater Global Manager, explained the system and its conclusions in the “Energy Efficiency and Renewable Energies” session.
Jesús Rivas said, “Collaborating with such a renowned company as Aqualia has been a great experience. I want to thank all Aqualia and WEG professionals for participating in this project, especially Luiz Gustavo Correa, Luiz Henrique Marcos, Maicon Martins Joaquim, and Marco Aurelio Goulart”.