Hot-membrane co-production sea water desalination method

Abstract

The invention relates to a hot-membrane co-production sea water desalination method which comprises an electric power plant sea water cooling system, an electric power plant sea water desulfurization system, an electric power plant smoke waste heat system and a sea water desalination system. Electric power plant flue gas waste heat is used for preheating sea water; the sea water enters the desalination system for desalination; the desalination system adopts a hot desalination system and a membrane desalination system which are in parallel; the defect that a hot method or a membrane method is used independently is overcome; waste gas waste heat is made full use of; water requirements in different regions and seasons are met; the fresh water cost is lowered; the thermal pollution to an environment is reduced; the salinity of the concentrated sea water after the desalination is 3.5-4%; the salt yield is increased by above 30% in comparison with common sea water; and the bromine production cost is lowered by approximately 50% in comparison with the common sea water.

Description

technical field [0001] The invention belongs to the technical field of desalination of seawater, and in particular relates to a method for desalination of seawater by thermal film cogeneration, that is, a combination of thermal method and membrane method, which meets different water demands and reduces the cost of fresh water. Background technique [0002] Water is the source of life, the lifeblood of social and economic development, and a precious and irreplaceable natural resource for human beings. According to statistics, the total amount of fresh water resources in my country is more than 2.8 trillion m 3 , ranking sixth in the world, but the per capita occupancy is only 2200 m 3 , only 1 / 4 of the world average. At present, my country's water resources are facing a very severe situation. Problems such as water resource shortage, serious water pollution, and water ecological environment deterioration have become increasingly prominent, and have become the main bottlenec...

AI Technical Summary

Problems solved by technology

[0003] Seawater desalination is a high-tech that is being studied in the world today, and it is an effective way to solve the shortage of fresh water resources. Currently, the seawater desalination methods on the market mainly include thermal method and membrane method. The thermal method is to heat and evaporate seawater, and then condense the steam to obtain fresh water. The process is simple to operate, but the cost is high and the energy consumption is large

Membrane method is mainly reverse osmosis (RO) technology. Reverse osmosis method is usually called ultrafiltration method. It uses semi-permeable membrane to allow water to pass through under pressure to intercept salt and impurities. Although reverse osmosis method is energy-consuming It is 10% to 20% lower than the thermal method, but because of the large membrane resistance, a high-pressure pump is required during operation, and the membrane is expensive, has a short life, and has a 50% attenuation every year; secondly, the reverse osmosis method is related to the water quality of seawater. Whether the water quality meets the requirements directly affects the service life of the osmotic membrane; at the same time, the reverse osmosis method has high requirements for seawater pretreatment, seawater regions, and seasonal water temperature changes

[0004] In short, the high cost is currently an important factor restricting the development of domestic seawater desalination, and it is also an important reason why desalinated water cannot be promoted on a large scale

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