Sea water desalination has been a dream pursued by humans for hundreds of years, and there have been stories and legends of removing salt from seawater in ancient times. The large-scale application of seawater desalination technology began in the arid Middle East region, but is not limited to that region. Due to over 70% of the world’s population residing within 120 kilometers of the ocean, seawater desalination technology has rapidly been applied in many countries and regions outside of the Middle East in the past 20 years.

But it was not until the 16th century that people began to make efforts to extract fresh water from seawater. At that time, European explorers used the fireplace on the ship to boil seawater to produce fresh water during their long voyages. Heating seawater to produce water vapor, cooling and condensing to obtain pure water is a daily experience and the beginning of seawater desalination technology.

Modern seawater desalination only developed after World War II. After the war, due to the vigorous development of oil by international capital in the Middle East, the region’s economy developed rapidly and its population increased rapidly. The demand for freshwater resources in this originally arid region continued to increase day by day. The unique geographical location and climate conditions of the Middle East, coupled with its abundant energy resources, have made seawater desalination a practical choice to solve the problem of freshwater resource shortage in the region, and have put forward requirements for large-scale seawater desalination equipment.

Since the 1950s, seawater desalination technology has accelerated its development with the intensification of water resource crisis. Among more than 20 desalination technologies that have been developed, distillation, electrodialysis, and reverse osmosis have all reached the level of industrial scale production and are widely used around the world.

In the early 1960s, multi-stage flash evaporation seawater desalination technology emerged, and the modern seawater desalination industry entered a rapidly developing era.

There are over 20 global seawater desalination technologies, including reverse osmosis, low multi efficiency, multi-stage flash evaporation, electrodialysis, pressurized steam distillation, dew point evaporation, hydropower cogeneration, hot film cogeneration, and the use of nuclear energy, solar energy, wind energy, tidal energy seawater desalination technologies, as well as multiple pre-treatment and post-treatment processes such as microfiltration, ultrafiltration, and nanofiltration.

From a broad classification perspective, it can be mainly divided into two categories: distillation (thermal method) and membrane method. Among them, low multi effect distillation, multi-stage flash evaporation, and reverse osmosis membrane method are the mainstream technologies worldwide. Generally speaking, low multi efficiency has the advantages of energy conservation, low requirements for seawater pretreatment, and high quality of desalinated water; The reverse osmosis membrane method has the advantages of low investment and low energy consumption, but it requires high requirements for seawater pretreatment; The multi-stage flash evaporation method has advantages such as mature technology, reliable operation, and large device output, but it has high energy consumption. It is generally believed that low efficiency distillation and reverse osmosis membrane methods are the future directions.