Breakthrough engineering is the core of ERI's PX® technology. It is no surprise that the PX Pressure Exchanger® is the most efficient energy recovery device on the market. The company has invested years in research and development efforts as well as millions of dollars to build the most efficient energy recovery device available today—up to 98% efficiency and energy savings of over 60%.

ERI's engineering capabilities cover a wide spectrum of disciplines, from specifying specialty materials to working with the latest design and analytical tools. We work with advanced materials such as ceramic, AL6XN*, 254SMO*, titanium and polymer composites. We also perform computational analyses of fluid dynamic and mechanical systems using hydraulic modeling software and finite element analysis (FEA) tools.

Our engineering department is headed by Dr. Richard Stover and supported by highly technical, qualified engineers. In addition, ERI's careful assembly of team of engineers and process designers are considered to be top in talent, expertise and experience in the desalination industry.

Together, the ERI team has over 120 man-years of experience in the design, installation, operation, retrofit, and troubleshooting of reverse osmosis seawater desalination plants. This group has shown an unmatched capability to provide consistent, strong support of our Pressure Exchanger® technology.

All our designs are produced with the state of the art Solid Works 3-D modeling software and we provide complete installation drawings, bill of materials, and exploded views for every model we make.

Re-thinking SWRO

PX® technology is a new paradigm in seawater reverse osmosis system design and operation. Because of this, there are fundamental differences between the way the traditional Pelton and turbo energy recovery systems of yesterday were designed and optimized compared with how the PX® system is designed and optimized today. Some of the new concepts and rules being driven by the ERI PX® are:

• PX®-equipped SWRO systems use less energy at lower recoveries (between 35% and 45%)
• The main high-pressure pump flow equals the systems permeate flow - only
• The main high-pressure pump and permeate flows are independent of the reject flow
• PX® efficiency is essentially independent of system flow rate and pressure changes
• The PX® is up to 98% efficient

These fundamental concepts literally reverse many of the traditional rules that have constrained the SWRO desalination designer for many years. PX® technology opens up new avenues for RO design and optimization using larger train sizes. It also allows the designer or operator to select a recovery rate which is optimum for a given salinity, temperature and membrane fouling performance. The papers below describe these ideas in detail:

Technology Shatters Design Barriers AMTA
SWRO at 2.0 kwh-m3 D&WR
Retro-Fitting Existing Systems, Euromed
Comparative Study D&WR

Process Design

The ERI Pressure Exchanger® has radically increased the flexibility with which SWRO designers can operate and optimize their desalination plants.To obtain the best results from applications based on PX® technology, designers must reconsider major SWRO design criteria. Water recovery rates, power train sizes, and high-pressure pump selection must take into consideration the energy reducing benefits of PX® technology. Similar considerations apply to retrofits of existing installations. Below are links to several relevant articles written by ERI's applications specialists. We recommend contacting us directly for assistance in applying the new paradigm that is the PX®.

Comparative Study D&WR
SWRO at 2.0 kwh-m3 D&WR
Technology Shatters Design Barriers AMTA
Retro-Fitting Existing Systems

Recovery Optimization

Using conventional energy recovery technology such as turbos and Pelton Wheels, membranes must be operated at extremely high water recovery rates to achieve energy efficiency—typically about 50% water recovery rate. With PX® technology, optimum power consumption is achieved within a very broad range from 30% – 55%. However, while optimum membrane utilization happens at the lower recovery rates, pretreatment costs must also be considered. The ERI team will work with your process engineers to show you why water recovery rates for most of SWRO plants being designed today have come down from 40% – 45% with normal salinity waters, and to less than 40% for most high salinity waters.

Our team has helped apply PX® technology to thousands of SWRO plants worldwide. These plants process seawater with various salinities, temperatures and organic loadings. The ERI team will work with your engineers to help you find the best solution for your type of seawater. Some of the technical papers in this website will help you with these considerations.

SWRO at 2.0 kwh-m3 D&WR
Technology Shatters Design Barriers AMTA

SWRO Train Optimization

A major economical benefit of PX® technology is that the PX® requires a much smaller high-pressure pump than that used by conventional technology. Even more crucial, PX® technology uniquely divorces the high-pressure pump from the energy recovery device. These two factors combine to give desalination plant designers much more flexibility in optimizing train sizes and selecting the best high-pressure pump for their project.

Another new challenge confronting the SWRO designer is selecting the correct high-pressure circulation pump-also known as the PX® booster pump. Equipped with a variable frequency drive (VFD), this booster pump establishes the flow control of the PX® device and becomes the crucial control device for the entire SWRO process. By changing the VFD setting of the circulation booster, the SWRO operator can control the plant water recovery ratio and hence, the operating pressure and membrane productivity. To help you meet this challenge, ERI designs and manufactures the first circulation booster pump specifically designed for applications with brine flows up to 80 cubic meters per hour. For larger flows, ERI can help you pick the right pump from major pump manufacturers such as Sulzer, David Brown Union, Afton, Indar and others. Click here for links to pump manufacturers.

Our team will help turn challenges into unlimited potentials for new, creative and competitive SWRO installations, and recommend the best solution for your type of seawater. Following are some of the train optimization projects we recently executed:

1. Evaluate and optimize various train sizes for a 140,000 m³/day SWRO plant in the China Sea.
2. Optimize HP pump selection and booster pump type for a 300,000 m³/day plant in Southern India
3. Triple SWRO OEM plant size using PX® technology
4. Correct deficiencies of circulation with booster design by collaborating with plant designers
5. Simplify major OEM plant design using the PX® "cascade" approach.

Technology Shatters Design Barriers AMTA
SWRO at 2.0 kwh-m3 D&WR

*AL6XN and 254smo is a registered trademark of Alegheny Ludlum