Wastewater evaporation concentration process and device system

Abstract

The invention discloses a wastewater evaporation concentration process and a wastewater evaporation concentration device system. The process comprises the following steps of: delivering softened wastewater to be treated to a mechanical vapor recompression (MVR) system to perform evaporation and concentration, compressing the generated secondary steam and then delivering the compressed steam to an evaporator to recycle, delivering the concentrate to a triple-effect mixed flow forced circulating evaporation crystallization system to perform evaporation and crystallization, performing solid-liquid centrifugal separation on the crystallized concentrate and crystal grains, returning the separated mother solution to a stock solution tank or continuously performing evaporation and crystallization, and reclaiming the separated crystal, wherein the secondary steam generated by evaporation and crystallization is recycled for the evaporation crystallization system. After the wastewater is evaporated and concentrated by adopting the process of mechanical vapor recompression circulating evaporation and triple-effect mixed flow forced circulating evaporation crystallization, the wastewater does not need to be discharged to the ground water area, and the wastewater is discharged in a form of steam or closed and embedded in a form of sludge or the like, so the purpose of zero discharge of the wastewater can be fulfilled; and the process system has high heat efficiency, low energy consumption, energy conservation, great reduction in running cost, low temperature difference, low corrosion, difficult scale formation and long equipment service life.

Description

technical field [0001] The invention relates to a waste water evaporation concentration process and a device system, belonging to the technical field of sewage treatment. Background technique [0002] At present, the commonly used follow-up advanced treatment methods for high-concentration industrial wastewater and / or desulfurization wastewater are: (1) seed crystal method: this process is to add crystal nucleus slurry to establish and maintain calcium sulfate crystallization during the brine circulation process of the evaporator, The evaporation of most of the water is completed in the brine concentrator, and the brine concentrator discharges brine with about 20% TDS, which is further concentrated and evaporated in the crystallizer, and the brine is concentrated into a rather thick crystal slurry and mother liquor (about solids). The crystallization slurry and mother liquor enter the drying spray chamber for drying, and are finally collected in the form of dry powder and s...

AI Technical Summary

Problems solved by technology

[0003] The seed crystal method has a good effect on wastewater treatment with a relatively low content of calcium ions and sulfate ions or one of the two in an industry or conventional water system, and the cleaning cycle is acceptable, but for already supersaturated systems When the desulfurization wastewater enters the preheater, scaling will occur soon due to the temperature rise and phase change. Once scaling is formed, it will be very difficult to clean, which will affect the operation and service life of the equipment.

[0004] The reverse osmosis concentration method requires pretreatment of RO influent, including turbidity, scaling substances, COD, etc., and the system is relatively complicated; the water quality of the recovered water is not as good as that of the seed crystal method, and the wastewater cannot be completely recovered, so it needs to be recycled to the surrounding environment or sewage collection system If a large amount of sewage is discharged into the existing sewage collection system, it will increase the difficulty and cost of subsequent sewage treatment

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