In this blog post, we will look at how desalination plant technology led by mechanical engineering can play a role in solving the water shortage problem.
A number of Korean companies are making their mark in the global plant market, and this plant industry is playing a key role in earning foreign currency as one of our major export items. The biggest reason why Korean companies can dominate the global market is their technological prowess. And at the center of this is mechanical engineering. My major is also mechanical engineering, and I am particularly interested in desalination plants, so I would like to explore this topic in more depth.
Human beings have long been trying to turn seawater into drinkable water. Since the time of ancient Egypt and Greece, there have been attempts to evaporate seawater to obtain fresh water, and during the Roman Empire, these methods were used for military purposes. However, the technology at the time was not very efficient, and the development of full-scale seawater desalination technology did not begin until the 20th century. Due to the increase in population and industrialization after World War II, the demand for water increased dramatically, and seawater desalination plants became an important technology in countries around the world.
First, let’s look at the word “plant.” In Korean, “plant” means “factory.” However, exporting a plant does not simply mean building a factory. It is a complex industry that provides various facilities and operational technologies. This plant industry is a technology-intensive, high-value-added industry that requires a lot of manpower, technology, time, and money.
Now, let’s look at the word “seawater desalination.” Seawater desalination is a technology that converts seawater into freshwater. It is a process of removing various salts and substances dissolved in seawater to make it into water that we can drink or use. In ancient times, the origin of seawater desalination was thought to be the method of boiling seawater and collecting the evaporated water vapor to obtain water, and simple desalination facilities were developed during World War II to supply water. Since then, seawater desalination technology has been continuously developed and has led to today’s large-scale plant industry.
Currently, the main technologies used in seawater desalination plants can be divided into three categories: reverse osmosis, multi-stage evaporation, and multi-effect.
The reverse osmosis method uses osmotic pressure to remove substances dissolved in seawater. Osmotic phenomena are the movement of water from the side with a lower concentration to the side with a higher concentration through a semipermeable membrane that only allows particles of a small size to pass through. Simply put, it is the same principle as when water moves toward the brine, like a cabbage pickled in salt water. Reverse osmosis is a method that uses this phenomenon in reverse to move seawater with a high concentration through a semipermeable membrane under high pressure. In this process, salt and impurities in seawater are filtered out to obtain fresh water.
The multi-stage evaporation method is a method of obtaining fresh water by dividing seawater into several stages, heating it, and generating and condensing water vapor by lowering the pressure. This method requires a lot of thermal energy, but is suitable for large-scale plants. The multi-effect method is similar to the multi-stage evaporation method, but it is characterized by the recycling of energy generated during the evaporation process to increase efficiency. This method is effective in reducing energy consumption by repeatedly lowering the pressure of seawater to produce water vapor and then condensing the water vapor to obtain fresh water.
The advantage of the reverse osmosis method is that it is highly energy efficient. However, the filter requires high maintenance costs and requires sophisticated management. The multi-stage evaporation method has a simple structure, but the disadvantage is that it consumes a lot of energy. The multi-effect method is relatively energy efficient because it recycles energy, but it requires a lot of initial installation costs due to its complex system. For example, several countries in the Middle East prefer the multi-stage evaporation method because of their abundant solar energy, while the reverse osmosis method is widely used in the United States and Europe.
As such, technologies that apply various physical principles are used in seawater desalination plants. Mechanical engineering plays a major role in developing efficient facilities and technologies by applying these natural phenomena. The core of seawater desalination technology is to mechanically implement phenomena such as seawater evaporation, heating, and water vapor condensation to produce fresh water on a large scale. In this process, mechanical engineering design, maintenance, and technology development that maximizes efficiency are essential.
Water is an essential 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 seawater desalination technology, which converts seawater into fresh water, is a very important technology for humanity. Seawater desalination plants are currently one of the most important export items in Korea. If the value of water increases further and the economic feasibility improves with technological advancements, the day will come when large-scale seawater desalination plants will be built in Korea. Furthermore, the water shortage problem caused by climate change and population growth is increasing the need for seawater desalination technology.
In the future, seawater desalination technology will develop further, which is directly linked to the development of mechanical engineering. Seawater desalination technology that combines environmentally friendly energy sources such as solar, wind, and wave power will open a new paradigm that can reduce costs and protect the environment at the same time. In addition, innovative developments in filters using nanotechnology are also expected. Mechanical engineering is at the heart of this innovation and will play an important role in solving the problem of fresh water in the future.
Therefore, seawater desalination plant technology is not only a proud achievement of mechanical engineering, but is also establishing itself as an essential technology for the sustainable development of humanity. I hope that more people will take an interest in this field and open up the future through mechanical engineering.
