Multistage cooling circulation freezing crystallization system and crystallization process thereof

Abstract

The invention discloses a multistage cooling circulation freezing crystallization system. The multistage cooling circulation freezing crystallization system comprises freezing heat exchangers, a freezing discharging tank, a freezing circulation pump, a freezing crystal mush pump, a first cyclone separator, a freezing crystal growing tank, a freezing discharging pump, a second cyclone separator, afreezing centrifugal buffer tank and a freezing centrifugal machine. The number of the freezing heat exchangers is at least two, and the multiple freezing heat exchangers are arranged in parallel. Thefreezing heat exchanger is communicated with the freezing discharging tank, and the freezing discharging tank, the freezing crystal mush pump, the first cyclone separator, the freezing crystal growing tank, the freezing discharging pump, the second cyclone separator, the freezing centrifugal buffer tank and the freezing centrifugal machine are sequentially communicated; and the freezing discharging tank is also communicated with each freezing heat exchanger through the freezing circulating pump. According to the multistage cooling circulation freezing crystallization system, efficient, stableand long-time operation of freezing crystallization is achieved, and meanwhile the purity and the recycling rate of crystalline salt are guaranteed.

Description

technical field [0001] The invention belongs to the field of water treatment, in particular to a multi-stage cooling cycle freezing and crystallization system and a crystallization process thereof. Background technique [0002] At present, with the improvement of national environmental protection policies, the pressure on enterprises to treat wastewater is gradually increasing. From the initial comprehensive utilization of wastewater to zero discharge, the treatment technology has evolved from simple chemical dosing treatment, ion exchange treatment, and membrane treatment to complex. Advanced oxidation, nanofiltration, electrocatalysis, high-pressure reverse osmosis, high-pressure nanofiltration, evaporation crystallization, freezing crystallization, etc., the technology is constantly innovating, and the process is also constantly lengthening. [0003] Through the combined optimization of the above-mentioned various process technologies, the entire recovery and utilization ...

AI Technical Summary

Problems solved by technology

However, these methods still cannot efficiently separate sodium chloride and sodium sulfate in wastewater, and cannot guarantee the purity and resource utilization of crystallized salt at the same time, resulting in an increase in mixed salt that cannot be reused

Although the combination of cold and hot methods can ensure the purity of crystallized salt and the utilization rate of resources at the same time, due to the lack of frozen crystallization engineering cases and the lack of experience of designers and manufacturers, frozen crystallization is easy to block and the temperature cannot be lowered to the design level. Value, short operation cycle, long cleaning and maintenance time, excessive sulfate radicals in the mother liquor after treatment, etc., the final output of mixed salt increases

[0004] Due to the large amount of impurities and complex components, mixed salt cannot be utilized as a resource, and it is difficult to process. At present, it is often disposed of by stacking or landfilling, which not only easily causes secondary pollution, but also requires a lot of manpower and financial resources. The gain outweighs the gain

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