Brief Introduction
Desalination is the use of seawater desalination to produce fresh water. It is an open source incremental technology that realizes the utilization of water resources. It can increase the total amount of fresh water and is not affected by time, space and climate. It can ensure stable water supply such as drinking water for coastal residents and industrial boiler water supply. The process of obtaining fresh water from seawater is called desalination. The seawater desalination methods currently used include seawater freezing method, electrodialysis method, distillation method, reverse osmosis method, and ammonium carbonate ion exchange method. At present, the application of reverse osmosis membrane method and distillation method is the mainstream in the market. There are more than one hundred scientific research institutions in more than ten countries in the world that are conducting research on seawater desalination, and there are hundreds of desalination facilities of different structures and different capacities in operation. A modern large-scale desalination plant can produce thousands, tens of thousands or even nearly one million tons of fresh water every day. The cost of water is constantly decreasing, and some countries have reduced it to almost the same price as tap water. The amount of desalinated water in some areas has reached the scale of national and urban water supply.
Process Flow
Low-temperature multi-effect seawater desalination technology refers to the distillation desalination technology in which the maximum evaporation temperature of brine is lower than 70°C. It is characterized by connecting a series of horizontal pipe spray falling film evaporators in series, and uses a certain amount of steam to enter the first effect. The evaporation temperature of the first effect is lower than the previous one, and then through multiple evaporation and condensation, the desalination process of distilled water that is multiple times the amount of steam is obtained.
Effective evaporation is to evaporate the heated seawater in multiple evaporators in series. The steam evaporated from the previous evaporator is used as the heat source of the next evaporator and condenses into fresh water. Among them, low-temperature multi-effect distillation is one of the most energy-saving methods in distillation. Low-temperature multi-effect distillation technology is developing rapidly due to energy-saving factors. The scale of the device is increasing, and the cost is decreasing. The main development trend is to increase the first-effect temperature and increase the single-unit water production capacity of the device; use cheap materials to reduce engineering costs and increase operating temperature. Improve heat transfer efficiency, etc. A low-temperature multi-effect distillation seawater desalination equipment includes a steam supply system, a water distribution system, an evaporator, a fresh water tank and a concentrated water tank. The raw steam inlet of the steam supply system is placed on an intermediate effect evaporator. The working method is: (1) The water distribution system sprays the seawater; (2) The raw steam is input to the inside of the evaporation tube of the intermediate effect evaporator; (3) The steam condenses in the evaporation tube and transfers heat, and the outside of the evaporation tube absorbs heat to produce Evaporation; (4) Fresh steam is delivered to the evaporation tubes on both sides. The outside of the tubes absorbs heat and produces evaporation; (5) Each effect evaporator repeats the evaporation and condensation process; (6) Distilled water enters the fresh water tank; (7) Concentrated brine Enter the thick water tank.
