Energy Recovery in desalination plants using heat exchangers

Background

A general background for explaining the need for energy recovery solutions:

Thermal desalination facilities using the Thermal Method were developed in the world several decades ago. The Israeli company "Desalination Engineering" (IDE Technologies) made a significant contribution to this technology. Thermal desalination is carried out by evaporation in a multi-stage facility, to which seawater is fed at a temperature of 5-25 degrees centigrade, whereby temperatures and pressures fluctuate. At the end of the desalination process, freshwater and brine products are obtained, both at 70 degrees centigrade. Heating such a large mass of water to such a high temperature, before the entering of the evaporator, would have rendered the process non-economical. Therefore, for the purposes of in-advance heating, residual output water heat is used, which must be cooled before storing and supplying the desalinated water for consumption and disposing the brine back into the sea. Without heat exchangers to perform this vital energy exchange, the thermal desalination plant has no economic justification.

Pictured: Facilities for seawater desalination using the thermal method.

The objective

Designing two sets of titanium plate heat exchangers. One for cooling brine and the other for cooling the desalinated water. The function of the arrays is to heat the seawater fed to the facility up to the temperature required in the client’s specifications. All of that in a facility that must function at the highest level of reliability and operate in a remote location that increases its maintenance costs.

The challenge

This application met many, stringent and special requirements:

- Compliance with heat exchange performance according to the most stringent specifications - Compliance with maximal pressure plunges allowed for energy efficiency, while fully utilizing them without maintaining safety ranges – all of the above must be performed while being able to calculate and to take into consideration the possible effect of the numerous flow passages on the heat exchangers’ performance – when designing rigid, durable, easy-to-maintain, rigorous equipment dimensions - excellent quality of gaskets and seals that allow for long-term pressure and maximum extension of the intervals needed to replace these gaskets - Providing top quality titanium plating - providing top-notch engineering and technical backing - providing maintenance servicing anywhere around the world as TRANTER, our global knowledge firm, enables.

The Project’s Solution

We designed and offered this Client to use Tranter Ultraflex Series Asymmetrical Plate Heat Exchangers. These unique plates deploying Ultraflex technology, enable the maximal utilization of the heat transfer areas for a rigorous thermal performance of the thermal desalination process. Complying with challenging and tough competition with all leading global manufacturers at all aspects: design creativity and engineering efficiency, quality of raw materials and production, proven performance levels, cumulative experience and reliability, previous projects and recommendations, competitive prices.

The outcome

We are proud to provide many heat exchangers for thermal desalination plants and others - a fact that speaks for itself. Desalination facilities operate the most accurate measuring instruments that have temperature measurement capabilities of up to one-tenth of a degree. Under such conditions, only a product that meets the specification requirements can be accepted by Clients in so many projects and in such long span of operating years. Our heat exchangers lead to minimization of financial costs for Clients – over a period of decades.

The "hi-tech" of heat transfer equipment

Heat exchangers used for energy recovery are the "hi-tech" of heat transfer equipment. We have proven that TRANTER's engineering and other capabilities, which we represent in Israel from the 1980s, combined with Krashin-Shalev's technology and engineering capabilities, allow us to successfully compete with the largest and most powerful corporations. All this would not have been possible without our consistent and uncompromising compliance with the most stringent customer requirements, especially in complex and challenging projects.