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What is Seawater Thermal Desalination?

Thermal desalination mimics the natural process of the water cycle; evaporation from the ocean, accumulation in the atmosphere, condensation as rain or snow, and collection. Since heat is vital in thermal desalination, the process is often linked to power plants and refineries to use waste heat. There are three main types of thermal desalination: mechanical vapour compression (MVC), multi-effect distillation (MED) and multi-stage flash distillation (MSF).

The Difference Between MED and MVC

In MED, water is boiled in successive stages (or ‘effects’), each at a lower temperature to reduce the amount of energy needed, with the boiling/condensation process delivering clean water. This process is the most energy efficient of the thermal processes, minimizing the need for pretreatment, and tolerates variations in the quality of the seawater. MED is highly reliable, simple to operate and has low maintenance costs. Nearly any heat source can be used, so it’s very adaptable.

In MVC distillation, when heat is delivered by compressed vapour, water evaporates and is collected while the heat is recycled back to the remaining feed water. Vapour compression is usually performed by mechanical means, typically electrically driven (Mechanical Vapour Compression). This is also very reliable and simple to operate.


Cost-effective, standalone MVC solutions

After pioneering thermal desalination for four decades, IDE is the industry’s most experienced provider and the source of the advanced technologies.

IDE’s self-contained MVC units are a reliable, cost-effective desalination solution for refineries, process industries, power stations and remote development sites, perfect for when electricity is the only source of power. Dozens of enterprises with a critical need for stable and reliable sources of process and boiler feed water have deployed the MVC as an affordable, low-maintenance, workhorse desalination solution.

IDE’s MVC units range in capacity from 250 to 3,000 m3/day and can be deployed in parallel to multiply production.

An automated, energy-efficient approach

IDE’s MVC concept utilizes a highly efficient ‘falling film’ distillation process, with an innovative application of the heat pump principle. This allows each MVC unit to create a continuous flow of highly pure water (1-5 ppm) while consuming an optimal quantity of externally supplied electricity. Throughout the process, energy is conserved and re-used, making the entire process highly energy efficient.

Cost-effective, efficient MED solutions

After pioneering thermal desalination for close to 50 years, IDE is the industry’s most experienced provider and the source of the majority of its advanced technologies.

IDE’s MED units are the industry’s most reliable, robust, and cost-efficient seawater desalination solutions, with capacities ranging from 600 to 25,000 m3/day per unit. They produce a reliable, low-cost stream of high-purity water for power plants and industries that can provide low-grade steam as an energy source. IDE customizes its MED solutions for the needs of each customer, including the site-specific characteristics of seawater and steam inputs.

The world's most advanced desalination technology

The MED units utilize the advanced technologies and know-how developed by IDE to achieve exceptional thermal efficiency and reliability. Their underlying concept is a multi-effect process in which a spray of seawater is repeatedly evaporated and then condensed, each taking effect at a lower temperature and pressure. This highly efficient process multiplies the quantity of pure water that can be produced using a given quantity of energy, resulting in a significant reduction in cost.


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