This article covers the history of desalination plants, their main technologies, and the contribution of mechanical engineering to their development. It also highlights the advantages, disadvantages, and future prospects of desalination technology, emphasizing that it will play an important role in solving humanity’s water scarcity problem.
Many Korean companies have made their mark in the global plant market, and the plant industry plays an important role in earning foreign currency as one of our major exports. The main reason why our companies are able to dominate the global market is technology. And mechanical engineering is at the center of it. My major is mechanical engineering, and I am particularly interested in seawater desalination plants, which is why I would like to delve deeper into this topic.
Humans have been trying to turn seawater into drinkable water for a long time. Since the time of the ancient Egyptians and Greeks, attempts have been made to evaporate seawater to obtain fresh water, and in Roman times these methods were utilized for military purposes. However, the technology was inefficient, and full-scale desalination didn’t begin to develop until the 20th century. Since World War II, desalination plants have become an important technology for countries around the world due to the rapidly growing population and increased demand for water due to industrialization.
First, let’s take a look at the word ‘plant’. Plant means “factory” in Korean. However, exporting plants doesn’t just mean building a factory. It’s a complex industry that provides all kinds of equipment and operating skills. It’s a technology-intensive, high-value-added industry that requires a lot of manpower, technology, time, and money.
Now, let’s look at the word “desalination”. Desalination is the process of converting seawater into fresh water. It is the process of removing various salts and substances dissolved in seawater to make it drinkable and usable. In ancient times, boiling seawater and collecting the evaporated water vapor is believed to be the origin of desalination, and during World War II, simple desalination plants were developed for water distribution. Since then, desalination technology has evolved to become the large-scale plant industry it is today.
Currently, there are three main technologies used in desalination plants: Reverse osmosis, multi-stage evaporation, and multi-utility.
Reverse osmosis uses osmotic pressure to remove dissolved substances from seawater. Osmosis is the movement of water from a lower to a higher concentration across a semi-permeable membrane that only allows small particles to pass through. In other words, like cabbage in a brine, water moves toward the brine. Reverse osmosis uses this phenomenon in reverse, applying high pressure to move water from highly concentrated seawater through a semi-permeable membrane into freshwater. In this process, the salts and impurities in the seawater are filtered out, and fresh water is obtained.
Multi-stage evaporation involves heating seawater in several stages, lowering the pressure to generate water vapor, and condensing it to obtain fresh water. This method requires a lot of thermal energy, but is suitable for large-scale plants. The multi-utility method is similar to the multi-stage evaporation method, but it is characterized by recycling the energy generated during the evaporation process to increase efficiency. The main energy-saving feature of this method is that it reduces the pressure of seawater to produce water vapor, which is then condensed to produce fresh water.
The advantage of reverse osmosis is its high energy efficiency. However, the filters are expensive to maintain and require sophisticated management. Multi-stage evaporation has a simple structure, but it has the disadvantage of high energy consumption. Multi-efficiency systems are relatively energy efficient because they recycle energy, but the complexity of the system means that initial installation costs are high. For example, many countries in the Middle East favor multi-stage evaporation because of their abundant solar power, while reverse osmosis is more popular in the United States and Europe.
As you can see, desalination plants use a variety of technologies based on different physical principles. Mechanical engineering has played a big role in developing efficient equipment and technologies that apply these natural phenomena. At the core of desalination technology is the mechanical realization of phenomena such as evaporation, heating, and condensation of seawater into water vapor to produce fresh water on a large scale. In this process, mechanical design, maintenance, and technology development to maximize efficiency are essential.
Water is an indispensable and precious resource for humanity. However, less than 2% of the water on Earth is fresh water that we can use. The remaining 98% is seawater, and desalination technology, which converts seawater into fresh water, is a very important technology for humanity. Currently, desalination plants are one of Korea’s most important exports. As water becomes more valuable and technology improves, it will not be long before large-scale desalination plants are built in Korea. Furthermore, water shortages caused by climate change and population growth are increasing the need for desalination technology.
In the future, desalination technology will become even more advanced, which is directly related to advances in mechanical engineering. Desalination technologies that combine green energy sources such as solar, wind, and wave power will open up a new paradigm in which cost savings and environmental protection can be achieved at the same time. Innovative developments in filters using nanotechnology are also expected. Mechanical engineering is at the center of these innovations and will play a key role in solving the freshwater challenges of the future.
Therefore, seawater desalination plant technology is not only a proud achievement of mechanical engineering, but also an essential technology for the sustainable development of mankind. We hope that more and more people will take an interest in this field in the future and use mechanical engineering to shape the future.
