We all know that two-thirds of a person consists of water. And if without food our body can last about a month, then without water, at best, only a week (sometimes much less). A person needs to consume enough fresh water daily to avoid any health problems. Desalination of sea water and the mechanism of its functioning is a topic more than relevant.
Industrial cleaning
Active population growth has directly affected the number of fresh water sources on our planet. As a result of this, there was a shortage of it, which prompted people to search for various ways to make drinking water “by hand”. The only way out was the possibility of desalination of salty sea water, not suitable for drinking.
The source for desalination was the oceans. Sea water goes through many stages of purification, as a result of which the liquid gets rid of the excess amount of various salts. The use of specialized installations comes to the rescue.
The use of desalination of sea water allows you to successfully bring it to a drinking state. Desalination of water on an industrial scale is carried out in various ways. Most of these methods are based on the use of dimensional energy-intensive installations. These are specialized filters and distillers. Consider the main types of desalination in large volumes.
Cleansing Methods
In our world, only a few technologies have been developed that allow you to convert sea water into running water. One of them is the use of chemicals. This method involves the use of special chemical compounds for desalination of liquids. In contact with salt water , a reaction occurs, as a result of which insoluble chemical compounds are formed.
After completion of the reaction, it remains only to remove the resulting precipitate by filtration. This method is not used in everyday life, and it is extremely rarely used for desalination of water in industry.
This method has quite significant disadvantages. Firstly, desalination will require a considerable amount of chemicals, secondly, the process takes a long time and, thirdly, it is not cheap.
Reverse osmosis method
This method has proven itself for a long time, nowadays it is actively used in industry. It uses special cleaning membranes. They are made of semi-permeable material. For example, from polyamide or cellulose.
Liquid with excess salts is passed through these membranes under a certain pressure. As a result, particles of liquid pass through a microscopic grid, on the surface of which larger particles of various impurities settle. Thanks to this method, it is possible to obtain a fairly large volume of desalinated water.
The principle of operation of the desalination of sea water
Desalination of seawater is a device that allows you to remove salts dissolved in it from a liquid. After passing this procedure, purified water is obtained. It can be used not only in everyday life, but also as good drinking water.
The design feature of the device is convenient and practical in operation. But fresh does not mean pure. Indeed, in it, one way or another, different components are stored. The use of the water obtained directly depends on their density. For example, on sea vessels completely different types of water are required:
- drinking - exclusively for cooking and drinking;
- water for personal hygiene and washing the deck;
- water for steam generators, otherwise it is called nutritious;
- technical water (used as a coolant for engines);
- distilled water.
For all these species, different marine desalination plants are used.
All methods are divided into two categories:
- Distillation - a desalination plant that works on the principle of distillation, heats and evaporates seawater. Then the steam is "caught" and brought to the desired temperature.
- Filtration - the principle of reverse osmosis. Salt water is desalinated without transition from one state of aggregation to another.
His work is based on "leveling" the concentration of dissolved impurities. Extremely high pressure allows you to "squeeze out" unnecessary particles of salts.
Interesting fact
The largest desalination plant in the world is located in Hadera (Israel). In terms of scale, this unit resembles almost a whole plant. Every year, it desalinates about thirty-three billion gallons of seawater.
This covers two thirds of the country's total demand. After all, as you know, in Israel there is an acute issue of the lack of drinking fluid. This desalination plant works, like most desalination plants, on the principle of reverse osmosis, under the influence of which the waters of the Mediterranean Sea are not subjected to heat treatment.
Solar water desalination plant
Recently, unique desalination plants have appeared on store shelves, interacting when working with solar energy. Inside the device, sea water is poured, from the received solar heat it turns into steam, condensing on the walls of the case, and settles in the lower part of the receiver.
The design of the installation is completely tight, it can create a greenhouse effect and does not allow evaporation from outside the desalination plant. Accordingly, as a result of this, more pure water is retained. At the end of this process, simply unscrew the cork and drain the purified water into a vessel.
Vacuum Desalination Plant
This type of desalination is used in the navy. It utilizes the heat of the fluid, which cools the main and auxiliary diesels. Pure water, heated to about sixty degrees Celsius, enters the inlet through the pipes of the heating battery. At the exit, the water temperature drops to about fifty-five degrees Celsius.
Vacuum desalination makes it possible to get about eight hundred liters of distilled water in an hour. This type of desalination plant can cover almost all the needs of fresh water without unnecessary expenses for fuel energy and maintenance. The device is fully automated. Since the temperature of the vapors is quite low, the desalination plant can work without purification for six to twelve months.
Instrument Maintenance
Maintenance of the device should be carried out every week, every month and once a quarter.
Once a week, an external inspection of the device is required. It is also worth checking the correct operation of the pump seals and rarely used valves. Eliminate loose fit and all kinds of leaks at the joints. Once a month, in addition to a weekly inspection, it is required to clean the seawater filter screen and lubricate the pump bearings. Once a quarter, the flowmeter is checked, and protectors on pipes, brine and pumps are replaced. The spray holes of the annular tube of the evaporator are cleaned, the stuffing box packing of the pumps is replaced.
Repair work
The repair process consists in dry cleaning the salt water heater and the evaporator-condenser with their subsequent pressure testing and rolling of the defective tubes.
It is necessary to open the liquid heater, clean the filters from the pipes and the tubes themselves from various debris and scale that has formed. You should also disassemble the flowmeter in order to clean it from dirt and rust. If the bearings of the pumps are worn, they must be replaced. Additionally, it is recommended to clean the surfaces of the housings in contact with sea water.
Yacht desalters for yachts
The presence of a desalination system on board a small vessel is comfortable and safe. Manual desalination of sea water saves the budget due to the lack of need for replenishment of clean drinking water.
On average, in an hour, such a desalination plant, designed for small sea vessels, processes hundreds of liters of salt water, turning it into pure drinking water.
Some models of desalination plants for yachts have a remote control function, which greatly facilitates the control of the process. Such installations are suitable for use on both sailing and motor yachts. Spare parts of marine desalination plants directly in contact with sea water are made from substances that are not affected by corrosion. The external design is most often made of stainless steel.
Portable water purifier
More recently, researchers have announced a new original device, created specifically for the separation of sea water into drinking and salt. The lion's share of desalination plants operates using reverse osmosis technology, while consuming a fairly large amount of electricity. The disadvantages of this method of desalination can also be attributed to the inefficiency of working with small volumes.
A new invention - a portable desalination plant based on polarization technology of ion concentration. The nanoscale channel is filled with liquid, an electric current is connected, which creates an electric field. Due to this, the water is divided into two parallel streams. In one of them ions of salts fall, in another stream there is pure fresh water.
The creators plan to bring to mind a new device that will be powered by alkaline battery energy. The planned rate of desalination is about fifteen liters per hour. They promise to launch the invention to the masses in the next two years.
How to make a seawater desalination do-it-yourself?
Water can be made clean without the use of industrial devices. To make a manual desalination plant is not difficult. To do this, you need a pan with a tight-fitting lid.
This method of desalination is based on the well-known physical phenomenon - condensation. Pour seawater into the pan, close the lid and boil. Steam accumulated under the lid is pure condensate. All water impurities have a large mass, so they settle to the bottom of the pan, and H 2 O particles condense in the form of steam.
This method allows desalination of a liquid with a large amount of pure water loss. Therefore, the design should be slightly improved. To do this, you need to make a small hole in the pan lid, insert a flexible hose (tube) into it, cover the pan with a lid. Direct the other end of the hose to the next pan (any container) and be sure to cover it with a damp towel. This will help the steam stay warm.
We put sea water on the fire and boil. We wait until all the water has “moved” to another pan. This will be desalinated drinking water. All salts, as well as various impurities, will remain in the same pan. Here is such a simple, self-made desalination of seawater will help to get clean drinking water.
Another way to desalinate salt water is to simply freeze it. The fact is that the freezing temperature of sea water and fresh is somewhat different. For freezing salty, a lower temperature is required than for freezing fresh. The resulting ice is desalinated water, which may well be suitable for drinking.
Desalination of seawater - a thing, of course, necessary, but only for an industrial scale. At home, you can convert sea water into drinking water using simple tricks that we met today. So now you can not worry about the fact that in an emergency the lack of water can turn into a serious problem.