The cost of desalination is mainly composed of two parts, what are they?

In a world where water resources are scarce and water pollution exacerbates water scarcity, countries are looking for ways to use water resources, and desalination is one of them. The cost of seawater desalination is relatively high, mainly including operating costs and maintenance costs.

Operating costs and maintenance costs are composed of labor costs, management costs, energy costs, equipment costs, equipment maintenance and repair costs, and other expenses. China's seawater desalination technology is not advanced enough compared with other foreign countries, and its high cost has also become a problem for China's seawater desalination industry. The cost of seawater desalination in China is about 4-5 yuan per ton, which far exceeds the daily water consumption of domestic residents.

Such a high ** may be difficult to be accepted by the public. However, in the future, China's seawater desalination technology will continue to improve, and the cost will continue to decrease, which is expected to enter the lives of the public.

At present, China's seawater desalination technology has not yet formed a complete industrial chain, and there is a large room for improvement in technological innovation and development, which is much behind compared with foreign countries. In addition, the scale of China's desalination industry needs to be expanded, and only a large enough scale can ensure China's water supply in the future. In order to solve some of the problems of seawater desalination, China has put forward five main tasks in the "Twelfth Five-Year Plan for the Development of Seawater Desalination Industry", which provides solutions for the development of seawater desalination technology.

Moreover, 9 safeguard measures are put forward in the "plan" to fully guarantee the development of seawater desalination technology, so as to promote the steady improvement of the seawater desalination industry. In order to better develop, China has also put forward a pilot unit of seawater desalination, which has further expanded the scale of the seawater desalination industry. The pilot unit applies seawater desalination to life, and gives priority to the use of water resources of seawater desalination in life, which provides rich experience for the promotion and application of seawater desalination in the future.

China is a country with a serious shortage of water resources, although the development of seawater desalination allows us to see the dawn of solving the shortage of water resources, but the most important thing is to save water in daily life, protect the environment to avoid water pollution.

The cost of electricity refers to the energy required for desalination, and the cost of financing refers to various aspects of financing factors.

One is the cost of equipment construction and labor, and the other is the depreciation of energy consumption materials, which will cause the cost of desalination.

The cost of desalination is mainly composed of operating expenses and maintenance costs. These two parts include management fees, staff salaries, total energy consumption costs (including electricity, gas, oil, etc.), medicines and other consumables.

The cost of desalination is mainly composed of two aspects: operating costs and maintenance costs, and the investment is apportioned under a certain ratio. Cost:

Management fees, staff salaries, total energy costs, annual maintenance costs, drug and other consumables costs, working capital interest, etc., as well as some reverse osmosis methods, also include membrane replacement costs.

Relevant experts in the field of seawater desalination in China have said that seawater desalination, as an incremental technology of water resources, is an important choice to solve the problem of water shortage in coastal water-scarce areas, and the development prospects of the empty tomato industry are broad.

In parallel with the word "broad prospects", the challenge of breakthrough development of seawater desalination is not small, and it still needs to make breakthroughs in many aspects such as system and technology, and there is still a long way to go to truly open up the prospects of seawater desalination industry.

According to the "2020 National Seawater Utilization Report" released by the Ministry of Natural Resources, there are 135 seawater desalination projects in China, with a project scale of 1651083 tons per day, and 14 new seawater desalination projects will be completed in the country in 2020. Compared with the previous year, the number of newly completed projects has decreased slightly, but the important thing is that from the overall perspective of the bucket stalls, the momentum of the steady development of the seawater desalination industry has been achieved.

Among them, there are 118 projects that apply reverse osmosis technology, accounting for the total scale, and all new desalination projects in 2020 use reverse osmosis technology. Another important information point is coming, the position of reverse osmosis technology in the seawater desalination industry is prominent, and a major mainstream direction of the development of seawater desalination technology falls into reverse osmosis technology.

Coupled with the goals set by the "Seawater Desalination Utilization Development Action Plan (2021-2025)" jointly issued by the Ministry of Natural Resources and the State last year, the total scale of seawater desalination in the country will reach more than 2.9 million tons per day in 2025. Judging from the scale of the project shown in the "2020 National Seawater Utilization Report", there are still nearly 130 tons of the established target in 2025, which is enough to see a large space for enterprises in the industry to play freely.

How does seawater desalination work? What is the best desalination method?

Among the more than 20 desalination technologies that have been developed, distillation, electrodialysis, and reverse osmosis have reached industrial-scale production applications.

Electrodialysis desalination is achieved using a specially manufactured thin film. Under the action of electricity, the positive ions of salts in seawater run through the positive membrane to the direction of the cathode, and cannot pass through the negative membrane and stay; Negative ions run through the anion to the anode direction, and cannot pass through the positive membrane and stay. In this way, the seawater in the pipeline where the salt ions are exchanged becomes fresh water, and the seawater in the pipeline where the salt ions are left becomes the concentrated brine.

Reverse osmosis desalination is even more subtle. The membrane it uses is called a "semi-permeable membrane". The performance of semi-permeable membranes is to allow only fresh water to pass through, not salts.

If no pressure is applied, this membrane is used to separate the brackish water from the fresh water, and the fresh water will automatically penetrate the brackish water. We apply pressure to the seawater through a high-pressure pump, and the fresh water in the seawater passes through the membrane to the fresh water, so it is called reverse osmosis, or reverse osmosis.

The principle of distillation is very simple, it is the principle that we prepare distilled water in the laboratory. The seawater is boiled, the fresh water evaporates into steam, the salt remains at the bottom of the pot, and the steam condenses into distilled water, which is fresh water. This ancient desalination method consumes a lot of energy and produces a lot of pot scale, making it difficult to produce fresh water in large quantities.

Modern multi-stage flash distillation desalination has rejuvenated the ancient distillation method. Water is heated to 100 degrees Celsius at normal air pressure before boiling to become steam. If properly heated seawater enters a vacuum or a near-vacuum distillation chamber, it will rapidly evaporate into steam in an instant.

Using this principle, a multi-stage flash distillation desalination device is made. This kind of desalination device can be built relatively large, and the vacuum evaporation chamber can be built more, connected to become a large-scale desalination plant. This kind of desalination plant can be built in conjunction with a thermal power plant to use the waste heat of the thermal power plant to heat seawater.

Combined hydropower can greatly reduce production costs. Most of the current large-scale desalination plants use this method. If the solar evaporation desalination method can be put into practice, the ancient distillation desalination technology will reach a new level of energy saving.

At present, seawater desalination has basically formed a new industrial sector. In 1975, the world's daily desalination production reached 2 million tons. Since then, it has grown at a rate of doubling every two years.

In 1975, Hong Kong built a desalination plant with a capacity of 180,000 tons per day, which was the world's most advanced desalination plant at that time. In 1983, a 300,000-ton-per-day desalination plant was built at the port of Jeddah, Saudi Arabia. Kuwait's seawater desalination capacity is more than 1 million tons per day.

The oil-rich countries in the Middle East have basically relied entirely on seawater desalination for their daily water.

Hope it helps.

In fact, the most advanced ones at present are the membrane method and the thermal method, and the other prospects do not seem to be great at present. The advantages of the thermal method are: first, it can use low-grade waste heat (it can be coupled with solar or nuclear waste heat); Second, it can be applied on a large scale, such as urban water supply; Third, the output water quality is high and stable.

Disadvantages: The construction location depends on the heat source, and the initial investment is large. Advantages of the membrane method:

There are many restrictions and low costs. Disadvantages: It needs to be replaced, and the water quality will decrease with the use time of the membrane.

However, with the improvement of the technical level of polymer technology materials, this shortcoming is becoming less and less obvious.