Crystallization treatment method and device of high salt wastewater

Abstract

The invention relates to a crystallization treatment method and device of high salt wastewater and belongs to the technical field of water treatment. The method is characterized in that after sodium sulfate concentrated water is treated by a freezing crystallization system, generated mother liquor A enters into an MVR system for evaporative crystallization; after sodium chloride concentrated water is treated by the MVR system, generated mother liquor B enters into a freezing crystallization system for freezing crystallization, and the mother liquor can be treated in a circulation overlapping manner; a drain outlet of the MVR system of the device is connected with a liquid inlet of a crystallization tank in the freezing crystallization system through a pipeline and the drain outlet of the freezing crystallization system is connected with a liquid inlet pipe of the MVR evaporative crystallization system. The method has the advantages that the mother liquor is treated by a freezing crystallization technology and an MVR evaporation crystallization technology in a circulation overlapping manner, so that the problems of zero emission and resource utilization are solved, and therefore, the energy consumption is effectively reduced and the operating cost is lowered.

Description

technical field [0001] The invention belongs to the technical field of water treatment, and in particular relates to a method and a device for treating mother liquor in a cycle of freezing crystallization and MVR evaporation crystallization. Background technique [0002] Freezing and crystallization technology is a technology that lowers the temperature of wastewater to about 0°C by freezing, and crystallizes wastewater based on the principle that the solubility of certain compounds in water is highly sensitive to temperature. The centrifuged mother liquor of freeze crystallization technology can only be partially circulated in the freeze crystallization system, because the water may contain some substances whose solubility does not change significantly with temperature. If the mother liquor is fully circulated, these substances will be enriched in the system and form dead Circulation, so part of the centrifuged mother liquor needs to be discharged from the system. [0003]...

AI Technical Summary

Problems solved by technology

The centrifuge mother liquor of MVR technology can theoretically achieve full circulation in the system, but because the ionic components contained in the wastewater are complex and not a single component, if the mother liquor is completely circulated, the final crystallization salt produced is too much, and the usable value is almost In addition, energy consumption has always been an important factor restricting the cost of evaporation technology. If the mother liquor is fully recycled, it will greatly increase the energy consumption of the system and increase the operating cost.

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