Quadruple-effect solvent recovery energy-saving system and method

Abstract

The invention discloses a quadruple-effect solvent recovery energy-saving system. The system comprises a first-effect recovery tower, a second-effect recovery tower, a third-effect recovery tower, a fourth-effect recovery tower, a first-effect evaporation tower, a second-effect evaporation tower, a third-effect evaporation tower, a first mother liquor raw material tank and a second mother liquor raw material tank. The method for recovering alcohol by using the system comprises the following steps: separately distilling the first mother liquor and the second mother liquor, and carrying out low-temperature distillation on the first mother liquor foamed by high-temperature distillation through the fourth-effect recovery tower and the third-effect recovery tower and distilling the second mother liquor which does not foam after high-temperature distillation through the first-effect evaporator, the first-effect recovery tower, the second-effect evaporation tower, the second-effect recovery tower, the third-effect evaporation tower and the third-effect recovery tower. Foaming in the distillation process is avoided, and meanwhile, the energy consumption in post-treatment on the waste liquid is reduced.

Description

technical field [0001] The invention relates to the technical field of alcohol recovery, in particular to a four-effect solvent recovery energy-saving system and method. Background technique [0002] At present, the alcohol content of the waste liquid after the alcohol extraction section is generally 50%-55%, and alcohol needs to be recovered through the alcohol recovery section. During alcohol recovery, the waste liquid with an alcohol content of 50%-55% is used as the mother liquor. At present, the mother liquor generally includes two types. The first mother liquor comes from the purification section of the alcohol extraction process, which contains water, ethanol and a large amount of organic matter, of which the organic matter content is about 1%, and it is easy to foam when distilled at a higher temperature; the second mother liquor This kind of mother liquor comes from the refining section of the alcohol extraction process. It contains water, ethanol, salt and a small ...

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Problems solved by technology

[0003] At present, in the recovery of alcohol, the two mother liquors are generally mixed and then distilled and recovered together. There are many problems in this distillation method: ① In order to ensure a good distillation recovery effect, multi-effect distillation is generally required. In order to achieve multi-effect distillation, in a In high-efficiency distillation, the temperature is generally higher, and the higher distillation temperature will cause the first mother liquor in the mixed liquor to foam and affect the distillation effect; ②The second mother liquor contains salt, and the salty wastewater produced after distillation needs to be evaporated The system recovers salt. The first mother liquor does not contain salt, and the wastewater generated after distillation is directly sent to the wastewater treatment system. The mixed distillation of the two mother liquors produces a large amount of wastewater, which increases the energy consumption of subsequent salt recovery.

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