High-temperature corrosion-resistant distillation seawater desalination system and method based on waste heat utilization of flue gas

Abstract

The invention discloses a high-temperature corrosion-resisting distilling seawater desalination system and method based on smoke waste heat utilization. The system comprises a high-temperature corrosion-resisting evaporation segment, a low-temperature evaporation segment, a condenser, a product water flash tank, a product water balancing tank, a strong brine flash tank, a strong brine balancing tank, an inter-effect pump, a feeding pump, a raw material water pump, a vacuum pump, a cooling water pump, a product water pump and a strong brine pump. According to the system, the low-temperature acid dew corrosion problem caused in the heat exchange process of high-temperature smoke and seawater and the deposition problem of inverse-solubility inorganic salt scale can be solved well, the safety, reliability and running stability of the system are greatly improved, and equipment and material investment cost is reduced. High-grade energy is scarcely consumed. The water making ratio is high. The operation temperature range is wide, the structure is compact, cleanliness and high efficiency are achieved, and the system and method are very suitable for low-cost and large-scale seawater desalination projects such as electricity and water co-production.

Description

technical field [0001] The invention relates to the technical fields of waste heat recovery and utilization and seawater desalination, in particular to a high-temperature corrosion-resistant distillation seawater desalination system and a seawater desalination method based on flue gas waste heat utilization. Background technique [0002] With the sustained and stable development of my country's economy, energy and environmental problems are becoming increasingly severe. In terms of energy, in addition to vigorously developing clean energy such as wind energy and solar energy, efforts must also be made to develop energy-saving technologies such as waste heat recovery and reuse. Waste heat widely exists in industrial equipment such as power plant boilers. According to its source, it can be divided into high-temperature flue gas waste heat, cooling medium waste heat, waste steam and wastewater waste heat, high-temperature product and slag waste heat, chemical reaction waste hea...

AI Technical Summary

Problems solved by technology

After the part of the high-temperature flue gas is heat-exchanged with seawater, the seawater temperature can be raised to 90°C or even higher, while the current large-scale distillation seawater desalination method (such as low-temperature multi-effect seawater desalination technology) has a maximum operating temperature of 70°C This is mainly due to the fact that inorganic salts with inverse solubility such as calcium carbonate, calcium sulfate, and magnesium hydroxide are easy to crystallize and deposit on the heat transfer surface under high temperature conditions, which seriously affects the heat transfer efficiency, and some metal heat transfer materials are in seawater. The corrosion rate will intensify with the increase of temperature. Therefore, the widely used low-temperature multi-effect distillation seawater desalination method is generally operated at low temperature, and the evaporation temperature range is generally 70-40 ° C, according to 2-5 ° C The operating temperature difference is designed, and the number of effects of the evaporator is generally not more than 15, which cannot match the seawater temperature (90°C or higher) after the high-temperature flue gas heat exchange, and the scaling of the scale under high-temperature operating conditions The tendency and the corrosion rate of heat exchange materials will be further enhanced

[0005] It can be seen that there is an urgent need to provide a new type of energy-saving recovery system using high-temperature flue gas, especially high-temperature sulfur-containing and nitrogen-containing flue gas waste heat, and a matching high-temperature corrosion-resistant seawater desalination system and its process method, which can not only withstand Corrosion of the heat exchange surface by the acid dew that occurs during the heat exchange and cooling process of the high-temperature flue gas, and can effectively avoid the decrease in heat transfer efficiency caused by the deposition of inverse solubility inorganic salts on the heat exchange surface under high temperature operating conditions above 90°C question

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