Deep energy-saving multi-effect evaporation system and process method

Abstract

The invention discloses a deep energy-saving multi-effect evaporation system and a process method. The system comprises a steam condenser, a wastewater preheater, an air preheater, a fan, a wastewater pre-concentrator, a pre-concentrated wastewater preheater, a first-effect heater, a first-effect separator, a first-effect circulating pump, a second-effect heater, a second-effect separator, a second-effect circulating pump, a thickening kettle, a centrifugal machine and a mother liquor pump. Salt-containing wastewater and air are preheated by the wastewater preheater and the air preheater respectively and then subjected to enhanced contact mass transfer in the wastewater pre-concentrator, a part of water is evaporated into the air to humidify the air to be close to saturated humidity, and the wastewater is concentrated to a certain degree and then enters the multi-effect evaporation system to be evaporated and crystallized. According to the invention, the fresh steam consumption of the multi-effect evaporation system can be further reduced, the purpose of deep energy conservation is achieved, and meanwhile, the operation is simple.

Description

technical field [0001] The invention belongs to the field of environmental protection, and in particular relates to a deep energy-saving multi-effect evaporation system and a process method. Background technique [0002] In terms of industrial wastewater treatment, zero-discharge technology can minimize the discharge of pollutants until no pollutants are discharged into the environment. Environmental pollution treatment investment and other aspects have inestimable value. For the zero-discharge treatment of high-concentration brine, the most effective and thorough solution is to use the evaporation crystallization process to realize all water reuse, salts and pollutants are concentrated and crystallized to be discharged from the factory in solid form and sent to the garbage treatment plant for landfill or to be disposed of. It is recycled as a useful chemical raw material. [0003] Multi-effect evaporation, that is, several evaporators are connected to operate, and the sec...

AI Technical Summary

Problems solved by technology

However, the secondary steam generated by the end effect of multi-effect evaporation is directly condensed with circulating cooling water. Since steam has a high latent heat of condensation, the latent heat is transferred to circulating cooling water without being utilized, resulting in a waste of energy.

But at the same time, the grade of the final steam is low, so it is difficult to directly use it in the evaporation system

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