High-salt and -solvent wastewater treatment system and process

Abstract

The invention discloses high-salt and -solvent wastewater treatment system and process. The outlet of a raw water pump is successively connected to a first heat exchanger and a second heat exchanger;the gas outlet of an inner coil evaporator is connected to a first rectifying column through a gas phase pipeline; the first rectifying column is successively connected to a second rectifying column and a third rectifying column through pipelines; a steam outlet of the first rectifying column is connected to a heat medium inlet of the first heat exchanger; the steam outlet of the second rectifyingcolumn is connected to a steam inlet of a falling-film evaporator; the liquid outlet of the inner coil evaporator is connected to two branch pipes: one is connected to the feeding inlet of the falling-film evaporator, wherein a gas-liquid separator is connected to a gas outlet of the falling-film evaporator and the gas outlet pipe of the gas-liquid separator is merged into the gas phase pipeline;the other one is connected to a centrifuge through the second heat exchanger, and the centrifuge is connected to the liquid inlet on the upper part of the inner coil evaporator through a delivery pump. The system achieves continuous desalting rectification, is high in purity of the recycled solvent, and can fully recycle and utilize residual heat.

Description

technical field [0001] The invention relates to a high-salt-containing solvent-containing wastewater treatment system and a process. Background technique [0002] At present, the waste desalination methods with high salt content and solvents are mainly divided into membrane method and thermal method. The membrane method is mainly reverse osmosis, nanofiltration, pervaporation and electrodialysis. First, the solvent is filtered through the membrane, and then desalted through membrane filtration; The method has low energy consumption and relatively simple system installation and maintenance. However, due to its easy pollution and short life, frequent cleaning and replacement of membrane materials are required, and the cost of desalination is high. Most organic membrane materials cannot be used in environments containing organic solvents or higher temperatures. Salt wastewater treatment. [0003] Therefore, at present, thermal methods are mostly used in industrialization. Ther...

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Problems solved by technology

[0002] At present, the waste desalination methods with high salt content and solvents are mainly divided into membrane method and thermal method. The membrane method is mainly reverse osmosis, nanofiltration, pervaporation and electrodialysis. First, the solvent is filtered through the membrane, and then desalted through membrane filtration; The method has low energy consumption and relatively simple system installation and maintenance. However, due to its easy pollution and short life, frequent cleaning and replacement of membrane materials are required, and the cost of desalination is high. Most organic membrane materials cannot be used in environments containing organic solvents or higher temperatures. Salt Wastewater Treatment

[0003] Therefore, at present, thermal methods are mostly used in industrialization. Thermal methods include multi-stage flash evaporation, low-temperature multi-effect distillation and pressure steam distillation, etc. Distillation solvent reuse, this method requires a complete set of equipment and a large amount of manual operation. At the same time, the centrifuged mother liquor contains some salt and other tar substances, resulting in the rectification also requiring a desalination device, and the mother liquor needs to be discharged in time because it contains tar. The stability of the system, the complexity of the system, the high operation requirements, and the continuity and automation are not strong

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