A method and device for evaporating and concentrating high-salt wastewater

Abstract

The invention discloses a high-salt wastewater evaporation concentration method and device, belonging to the technical field of high-salt wastewater treatment. The method comprises a process of heating high-salt wastewater for evaporation and concentration. The method is characterized by comprising the following steps: carrying out oriented scale formation before heating the high-salt wastewater, heating the high-salt wastewater by using a surface-type heat exchanger, and evaporating the heated high-salt wastewater by using a mechanical draught cooling tower, wherein the heat medium water adopted in the surface-type heat exchanger is circulating cooling water flowing out of the steam condenser. The circulating cooling water of the condenser is utilized to perform heat exchange and heating on the high-salt wastewater, and the heated high-salt wastewater is sent into the mechanical draught cooling tower for evaporation, thereby lowering the heat loss of the circulating cooling water of the condenser, enhancing the cooling efficiency of the condenser, and lowering the high-salt wastewater treatment cost.

Description

technical field [0001] The invention relates to the technical field of high-salt wastewater treatment, in particular to a high-salt wastewater evaporation concentration method and device. Background technique [0002] At present, large-scale industrial factories in my country will produce a kind of high-salt wastewater. This high-salt wastewater is produced by membrane concentration in boiler feed water treatment or system blowdown in wet desulfurization process. The pollution factors of this high-salt wastewater are heavy metals, Salt, etc., if discharged directly into the water, it will pollute the environment. The discharge of high-salt wastewater from the power plant not only increases the cost of water resources and sewage charges of the power plant, but also brings a lot of inconvenience to the preparation and operation of the project. [0003] On the other hand, the circulating cooling water system of the condenser that condenses the exhaust steam of the steam turbine ...

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Problems solved by technology

[0002] At present, large-scale industrial factories in my country will produce a kind of high-salt wastewater. This high-salt wastewater is produced by membrane concentration in boiler feed water treatment or system blowdown in wet desulfurization process. The pollution factors of this high-salt wastewater are heavy metals, Salt, etc., if discharged directly into the water, it will cause environmental pollution. The discharge of high-salt wastewater from the power plant will not only increase the cost of water resources and sewage discharge fees of the power plant, but also bring a lot of inconvenience to the preparation and operation of the project.

[0003] On the other hand, the circulating cooling water system of the condenser that condenses the exhaust steam of the steam turbine is composed of a condenser, a circulating pump, a cooling water circulation pipeline, a cooling tower, etc., and a large amount of waste heat in the cooling water is lost in the cooling tower in the form of water vapor. It causes waste, and at the same time, after the water vapor is lost, the salt content of the cooling water is increased. It is necessary to ensure the dynamic balance of the salt in the circulating cooling water system through sewage discharge and water replenishment, thus increasing the consumption of cooling water.

[0004] According to the regulations of DL / T5196, in thermal power plants that generate desulfurization wastewater, the monitoring of sulfate concentration should be added at the wastewater outlet of the plant area. It is generally stipulated that power plants with wet flue gas desulfurization should be equipped with independent desulfurization wastewater treatment devices; Thermal separation technology concentrates the liquid solution. In the power industry, the evaporation device is mainly used to concentrate the crystallization and liquid separation of high-salt wastewater. Evaporation of high-salt wastewater requires heating first, which consumes a lot of energy and increases the cost of high-salt wastewater treatment. At the same time, the concentration of scaling factors in the high-salt wastewater increases during the heating process, which causes scaling on the heat exchange surface for heating the high-salt wastewater, which affects the heat exchange efficiency, seriously damages the heat exchange equipment and pollutes the water quality of the heat medium

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