Three-tower two-effect rectification system and recovery method for NMP waste liquid

A recovery method, waste liquid technology, applied in separation methods, chemical instruments and methods, steam condensation, etc.

Inactive Publication Date: 2021-05-18
常州冀德环保科技有限公司
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  • Abstract
  • Description
  • Claims
  • Application Information

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Problems solved by technology

[0004] The purpose of the present invention is to provide a three-tower two-effect rectification system and recovery method for NMP waste liquid in o

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  • Three-tower two-effect rectification system and recovery method for NMP waste liquid
  • Three-tower two-effect rectification system and recovery method for NMP waste liquid

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Embodiment Construction

[0042] The following will clearly and completely describe the technical solutions in the embodiments of the present invention with reference to the accompanying drawings in the embodiments of the present invention. Obviously, the described embodiments are only some, not all, embodiments of the present invention.

[0043] A kind of recovery method of NMP waste liquid, NMP recovery in the waste liquid comprises the following steps:

[0044] Step 1: The waste liquid containing NMP is pumped into the feed preheater through the waste liquid pump, and then enters the first-stage concentration tower after being preheated by the steam flashed by steam condensate;

[0045] Step 2: After preheating, the waste liquid enters the primary concentration tower for the first dehydration and concentration. The temperature at the top of the primary concentration tower is 45.5°C, and the corresponding temperature of the tower kettle is 52°C;

[0046] Step 3: After being dehydrated and concentrate...

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Abstract

The invention relates to the technical field of solvent recovery, in particular to a method for recovering NMP waste liquid. The method for recovering NMP in the waste liquid comprises the following steps: step 1, preheating the waste liquid containing NMP and then feeding the waste liquid into a primary concentration tower; step 2, preheating the waste liquid, and carrying out primary dehydration concentration in the primary concentration tower; step 3, feeding tower bottom liquid which is dehydrated and concentrated by the primary concentration tower into a flash tank through a discharging pump, and then feeding the tower bottom liquid into a feeding evaporator by using a forced circulation pump; step 4, carrying out secondary dehydration and concentration on gas of which the gas phase enters the secondary concentration tower in the secondary concentration tower; step 5, feeding tower bottom liquid dehydrated and concentrated by the secondary concentration tower to the middle part of a rectifying tower by a discharging pump so as to separate a mixed solution; and step 6, pumping the NMP finished product into a finished product cooler, cooling by circulating water, and then feeding into a finished product tank in a tank area. The whole technological process is carried out at low temperature, and NMP is basically not decomposed, so that the recovery rate of an NMP finished product is about 99.5%.

Description

technical field [0001] The invention relates to the technical field of solvent recovery, in particular to a three-tower two-effect rectification system and a recovery method for NMP waste liquid. Background technique [0002] NMP, also known as N-methylpyrrolidone, is an excellent high-grade solvent, a polar solvent with strong selectivity and good stability. Widely used in industries such as lithium batteries, medicine, pesticides, pigments, cleaning agents, and insulating materials. NMP waste liquid (NMP content is about 20-50%) is generated during use. Currently, rectification is used to treat NMP waste liquid It is the best choice. There are many rectification and recovery methods for NMP waste liquid in China, but there are two common problems: high energy consumption and high operating temperature. [0003] The Chinese patent No. CN108658829A discloses a method for recovering and refining NMP, which is a three-tower single-effect rectification recovery method in terms...

Claims

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Application Information

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IPC IPC(8): B01D5/00C07D207/267
CPCB01D5/006B01D5/0051B01D5/009C07D207/267
Inventor 章旭元
Owner 常州冀德环保科技有限公司
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