High-temperature seawater desalting and distillation device and method

Abstract

The invention relates to a high-temperature seawater desalting and distillation device and method. The device comprises a preheater, a multi-effect evaporator, respective-effect gas-liquid separators and a circulation pump. A vertical evaporator is adopted, the steam is heated in the equipment initial operating stage for gradually preheating calcium removed seawater stage by stage, secondary steam generated in the evaporation process is used for preheating the seawater, condensed water generated by the respective-effect gas-liquid separators is used for initial seawater preheating, the condensed water after the secondary steam seawater preheating is used for preheating the seawater after the heat exchange by condensed water generated by the separators, the heat efficiency is improved, the heating steam heat loss is reduced, the self afterheat of a system is sufficiently utilized, and the recovery rate of fresh water is improved. The device and the method are applicable to calcium removed or calcium and magnesium removed seawater, the heating temperature can be 40 to 170 DEG C, the heating temperature range is wide, the scale accumulation limitation is avoided, the total dissolved solids (TDS) of the desalted strong brine can be 50000 to 250000 mg/L, and the recovery rate of the fresh water is 40 to 75 percent. High-concentration, high-temperature and high-quality raw materials are provided for factory salt preparation, and the firm foundation is laid for the zero discharge of the seawater desalting.

Description

technical field [0001] The invention relates to a high-temperature seawater desalination distillation device and method. It is composed of a primary preheater, a secondary preheater, each effect preheater, a multi-effect evaporator, each effect gas-liquid separator, and a circulating pump. The purpose is to improve the thermal efficiency, reduce the heat loss of heating steam, make full use of the waste heat of the system itself, and achieve the purpose of increasing the recovery rate of fresh water. The present invention is suitable for seawater after decalcification or calcium and magnesium removal, the heating temperature can be 40-170°C, the heating temperature range is wide, and it is not limited by scaling. 40-75%. Background technique [0002] Seawater desalination has been included in the unified planning of national water resources and will become an important supplement to water resources. Therefore, the future development prospect of seawater desalination is ex...

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Problems solved by technology

[0006] At present, most low-temperature multi-effect seawater desalination devices at home and abroad are horizontal evaporators, and the evap

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