Wastewater evaporating process and device system

Abstract

The invention discloses a wastewater evaporating process and device system. The wastewater evaporating process comprises the following steps: the wastewater to be treated firstly enters a pretreatment softening system for softening treatment and secondly enters a mechanical vapor recompression (MVR) system for evaporation concentration; the generated secondary steam is compressed and enters an evaporator for recycling; the concentrated solution enters a triple effect flow-mixing forced circulation evaporation and crystallization system for evaporation and crystallization; the generated secondary steam is reused by the evaporation and crystallization system; the concentrated solution and crystalline grains obtained through crystallization are subject to solid-liquid centrifugal separation;the separated mother solution is sent back to a raw liquor tank or evaporated continuously for crystallization; and the separated crystals enter a centrifugal drying and packaging system for weighting and packaging. After the process disclosed by the invention is adopted to soften, evaporate and crystallize wastewater and dry and package the obtained crystals, wastewater is not discharged to the water bodies of the surface of earth and the aim of zero wastewater discharge can be realized; the process system is low-carbon and environmentally friendly; the material can be recycled, the thermal efficiency is high, the energy consumption is low, the energy can be saved, the operating cost can be greatly reduced, the range of temperature is small, the corrosion is low and the service life of the equipment is long, and the scaling has small possibility of occurrence.

Description

technical field [0001] The invention relates to a waste water evaporation process and a device system, in particular to a high-concentration industrial waste water and / or desulfurization waste water evaporation process and a device system, and belongs 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 ...

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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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