Wastewater zero-discharge treatment system

Abstract

The invention provides a wastewater zero-discharge treatment system, which is composed of a waste-gas waste-heat utilization system, a low-temperature multi-effect horizontal pipe distillation system and an evaporative crystallization system, wherein the low-temperature multi-effect horizontal pipe distillation system is a MED (Multi-Effect Distillation) system; the waste-gas waste-heat utilization system comprises a combustion gas turbine capable of combusting gas to discharge high-temperature smoke, and a waste-heat boiler making use of the waste heat of the high-temperature smoke so as to obtain high-temperature steam; the low-temperature multi-effect horizontal pipe distillation system comprises a low-temperature multi-effect evaporator and a condenser; and the evaporation crystallization system comprises a stand-pipe falling-film evaporator making use of the high-temperature steam to purify wastewater and a drying device. The wastewater zero-discharge treatment system disclosed by the invention has the beneficial effects that low-grade energy can be used as a heating source to realize multiple reutilization of heat, so that distillation consumption is reduced greatly; and the concentration of brackish water is realized, so that crystallized salt is separated from distilled water and the zero discharge of the brackish water is realized.

Description

technical field [0001] The invention belongs to the field of wastewater treatment, and in particular relates to a technical method for realizing zero discharge of wastewater by coupling low-temperature multi-effect evaporation and vertical tube falling film evaporation process. Background technique [0002] At present, mine water in coal mines and industrial wastewater in chemical enterprises mostly use vertical tube falling film evaporation technology. The heat transfer temperature difference of the single-effect evaporator of this technology must be above 15°C, usually 20°C. For the use of 0.5MPa, For a steam source of 140°C, the evaporator effect number of vertical tube falling film evaporation usually adopts 2 effects, and at most does not exceed 4 effects, so the evaporation energy consumption is relatively high. The low-temperature multi-effect evaporator has the characteristics of small temperature difference heat transfer. The multi-effect evaporator can be arranged ...

AI Technical Summary

Problems solved by technology

[0002] At present, mine water in coal mines and industrial wastewater in chemical enterprises mostly use vertical tube falling film evaporation technology. The heat transfer temperature difference of the single-effect evaporator of this technology must be above 15°C, usually 20°C. For the use of 0.5MPa, For a steam source of 140°C, the evaporator effect of vertical tube falling film evaporation usually adopts 2 effects, and at most does not exceed 4 effects, so its evaporation energy consumption is relatively high

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