CN-122006279-A - System for get rid of alcohol amine class material in NMP recovery liquid

CN122006279ACN 122006279 ACN122006279 ACN 122006279ACN-122006279-A

Abstract

The invention discloses a system for removing alcohol amine substances in NMP (N-methyl pyrrolidone) recovered liquid, which comprises a dehydration rectifying tower, a reaction separating tower, a product refining tower and a reaction and reaction separating tower reboiler serving as a reactor, wherein the dehydration rectifying tower is respectively connected with the reaction separating tower and the product refining tower, the reaction and reaction separating tower reboiler is connected with the reaction separating tower, the reaction and reaction separating tower reboiler is connected with the dehydration rectifying tower or the product refining tower, the reaction and reaction separating tower reboiler comprises an outer heat exchange tube, an inner reaction heat exchange tube is arranged in the outer heat exchange tube, the inner reaction heat exchange tube is an inner reinforced heat exchange tube, the reaction and reaction separating tower reboiler is provided with an inner tube plate for separating a shell side from an outer heat exchange tube side and an outer tube plate for separating an outer heat exchange tube side from an inner reaction surrounding tube side, and the optimal reaction condition and the reaction process are simultaneously coupled with the rectification separating process are designed, so that the alcohol amine substances in NMP are removed with high yield, high reaction rate and energy conservation.

Inventors

LI TIANYOU
MENG JILI
Huang Jiandian

Assignees

广东天瑞德新能源科技有限公司

Dates

Publication Date: 20260512
Application Date: 20251205

Claims (14)

1. The system for removing the alcohol amine substances in the NMP recovered liquid is characterized by comprising a dehydration rectifying tower, a reaction separating tower, a product refining tower and a reaction and reaction separating tower reboiler serving as a reactor; The dehydration rectifying tower is respectively connected with the reaction separating tower and the product refining tower; the reaction and reaction separation tower reboiler comprises an outer heat exchange tube; an inner reaction heat exchange tube is arranged in the outer heat exchange tube; The internal reaction heat exchange tube is an internal reinforced heat exchange tube; the reaction and reaction separation tower reboiler is provided with an inner side tube plate for separating a shell side from an outer heat exchange tube side and an outer side tube plate for separating the outer heat exchange tube side from an inner reaction surrounding tube side; The outer heat exchange tube of the reaction and separation tower reboiler is connected with the reaction and separation tower; when the ethanolamine is removed, the internal reaction heat exchange tube of the reaction and reaction separation tower reboiler is connected with the dehydration rectifying tower; when the propanolamine is removed, the internal reaction heat exchange tube of the reaction and reaction separation tower reboiler is connected with the product refining tower.
2. The system for removing alcohol amine substances from NMP recovery liquid according to claim 1, wherein a supporting piece is arranged between the outer heat exchange tube and the inner heat exchange tube of the reaction and reaction separation tower reboiler at intervals of 1-1.5 m along the axial direction.
3. The system for removing alcohol amine substances from NMP recovered liquid according to claim 2, wherein the outer heat exchange tube of the reboiler of the reaction and reaction separation tower is concentric with the inner heat exchange tube, and the supporting members are uniformly distributed in the radial direction of the outer heat exchange tube.
4. A system for removing alcohol amine-like substances from NMP recovery liquid according to claim 3, wherein said supporting members are provided at every 120 degree intervals in the radial direction of the outer heat exchange tube of said reaction and reaction separation tower reboiler.
5. The system for removing alcohol amine substances from NMP recovery liquid according to claim 2, wherein the inner reaction heat exchange tube supporting member of said reaction and reaction separation tower reboiler is arranged in an arc shape at a position contacting with said outer heat exchange tube.
6. The system for removing alcohol amine substances from NMP recovered liquid according to claim 1, wherein the internal reinforced heat exchange tube of the reboiler of the reaction and reaction separation tower is an internal thread reinforced heat exchange tube or a spiral coil is inserted into the internal reaction heat exchange tube.
7. A system for removing alcohol amine material from NMP recovery liquid according to any one of claims 1 to 6, further comprising a dehydration column feed static mixer; the top output end of the reaction separation tower is connected with the first input end of the dehydration tower feeding static mixer; the second input end of the dehydration tower feeding static mixer is used for being connected with NMP waste liquid raw materials; the output end of the NMP waste liquid raw material is connected with the input end of the dehydration rectifying tower.
8. The system for removing alcohol amine substances from NMP recovery liquid according to any one of claims 1 to 6, further comprising a side draw pump, a reaction feed static mixer, an on-line titrator, a reaction feed flow controller, and a fourth regulating valve; the output end of the side line discharging pump is connected with the first input end of the reaction feeding static mixer; The detection point of the online titrator is connected to a pipeline between the output end of the side stream discharge pump and the first input end of the reaction feed static mixer, a control system calculates a set value of reaction flow according to a detection result, and the quantity of the input anhydride substances is regulated through the reaction feed flow controller and a fourth regulating valve; the second input end of the reaction feed static mixer is used for inputting anhydride substances; The output end of the reaction feeding static mixer is connected with the input end of the internal reaction heat exchange tube of the reaction and reaction separation tower reboiler, and the output end of the internal reaction heat exchange tube of the reaction and reaction separation tower reboiler is connected with the input end of the reaction separation tower; When ethanolamine is removed, the lateral line discharge end of the dehydration rectifying tower is connected with the input end of the lateral line discharge pump; When the propanolamine is removed, the lateral line discharge end of the product refining tower is connected with the input end of the lateral line discharge pump.
9. The system for removing alcohol amine material from NMP recovery liquid according to claim 8, wherein when said acid anhydride material is maleic anhydride and ethanolamine is removed, the ratio of the amount of maleic anhydride added to the amount of ethanolamine material is in the range of 0.3, 0.7; When the acid anhydride is maleic anhydride and the propanolamine is removed, the amount of the propanolamine added to the maleic anhydride ranges from [0.3,0.5].
10. The system for removing alcohol amine substances from NMP recovered liquid according to claim 9, wherein when the acid anhydride substance is maleic anhydride and the ethanolamine is removed, the temperature of the reboiler of the reaction and reaction separation tower is controlled to be 120-135 ℃, and the reaction pressure is not lower than 25KPa; When the anhydride substance is maleic anhydride and propanolamine is removed, the temperature of the reaction and reaction separation tower reboiler is controlled to be 120-135 ℃, and the reaction pressure is not lower than 15KPa.
11. A system for removing alcohol amine substances in an NMP recovery liquid according to any one of claims 1 to 6, wherein the reaction separation tower is filled with two layers of metal wire mesh packing; The first packing layer from top to bottom corresponds to 5-10 theoretical plates, and the second packing layer corresponds to 5-10 theoretical plates; When the ethanolamine is removed, the operation temperature of the top of the reaction separation tower is 39-65 ℃, the operation temperature of the bottom of the reaction separation tower is 125-135 ℃, and the operation pressure of the top of the reaction separation tower is 1-5 KPa; when the propanolamine is removed, the operation temperature of the top of the reaction separation tower is 39-70 ℃, the operation temperature of the bottom of the reaction separation tower is 125-135 ℃, and the operation pressure of the top of the reaction separation tower is 1-5 KPa.
12. A system for removing alcohol amine substances in NMP recovery liquid according to any one of claims 1 to 6, characterized in that when ethanolamine is removed, the dehydration rectifying tower is filled with three layers in total, and a wire mesh filler is used; the first packing layer from top to bottom is equivalent to 4-8 theoretical plates, the second packing layer is equivalent to 6-12 theoretical plates, and the third packing layer is equivalent to 10-24 theoretical plates; when the propanolamine is removed, the dehydration rectifying tower is filled with two layers, and a wire mesh filler is adopted; The first packing layer from top to bottom corresponds to 10-20 theoretical plates, and the second packing layer corresponds to 10-20 theoretical plates.
13. The system for removing alcohol amine substances from NMP recovered liquid according to claim 12, wherein the operation temperature of the top of the dehydration rectifying tower is 39-46 ℃, the operation temperature of the bottom of the tower is 130-135 ℃, and the operation pressure of the top of the tower is 7-10 KPa.
14. A system for removing alcohol amine substances in an NMP recovery liquid according to any one of claims 1 to 6, wherein said product refining column is filled with two layers of wire mesh packing; When ethanolamine is removed, the first packing layer from top to bottom is equivalent to 5-10 theoretical plates, and the second packing layer is equivalent to 5-10 theoretical plates; The operation temperature of the top of the product refining tower is 85-105 ℃, the operation temperature of the bottom of the product refining tower is 115-130 ℃, and the operation pressure of the top of the product refining tower is 2-4 KPa; when the propanolamine is removed, the first packing layer from top to bottom is equivalent to 20-36 theoretical plates, and the second packing layer is equivalent to 20-36 theoretical plates; the operation temperature of the top of the product refining tower is 75-95 ℃, the operation temperature of the bottom of the product refining tower is 105-115 ℃, and the operation pressure of the top of the product refining tower is 1-2.5 KPa.

Description

System for get rid of alcohol amine class material in NMP recovery liquid Technical Field The invention relates to the field of new energy and environmental protection, in particular to a system for removing alcohol amine substances in NMP. Background In the preparation process of a precursor of a positive electrode material or a negative electrode material in a lithium ion battery system, alcohol amine substances (such as ethanolamine, diethanolamine, triethanolamine and the like) are commonly used for synthesizing metal oxide or phosphate positive electrode materials (such as LiFePO4, NMC and the like) by a solution chemical method. The catalyst can be used as a complexing agent to be combined with metal ions, and the concentration balance of the metal ions in the solution is controlled, so that the crystal growth and the particle size distribution are affected, and more uniform electrode active material particles with controllable particle sizes are obtained. In addition, in the slurry preparation process (such as electrode coating slurry preparation), the alcohol amine substance can be used as a dispersing agent or a viscosity regulator, so that particles in the slurry are more uniformly distributed and stably suspended, the uniformity of the coating is improved, and the quality of electrode finished products is improved. N-methyl pyrrolidone (NMP for short) is an important chemical solvent, has the characteristics of low toxicity, high boiling point, strong dissolving power, good selectivity and good stability, and is the most commonly used solvent in the production of metal ion batteries. NMP can be mutually dissolved with water, PVDF, positive electrode material, negative electrode material and other substances, so that the NMP is widely applied to the preparation of lithium batteries, and when electrode plates are manufactured, NMP is used as a solvent, and various substances required by electrodes such as a binder, a positive electrode active substance, a conductive agent and the like can be fused together, so that the binder is fully contacted with other substances and uniformly distributed. The conventional technological process in the current market is as follows, the slurry of electrode material (mixture of nickel cobalt lithium manganate, conductive carbon black, solvent NMP, binder PVDF and additive) is uniformly coated on two sides of aluminum foil, and a dryer adopts a closed negative pressure air draft dryer (drying channel). After the coating is completed, the positive electrode sheet is baked and dried in a vacuum dryer to remove the solvent, such as NMP and a part of the alcohol amine additive, on the electrode. And (3) the dried solvent gas enters a solvent recovery device to obtain a recovery solvent containing N-methyl pyrrolidone, trace alcohol amine additives, trace water and pyrolysis heavy components. NMP at a boiling point of 204 ℃, ethanolamine at a boiling point of 170 ℃, diethanolamine at a boiling point of 271.1 ℃, triethanolamine at a boiling point of 335.4 ℃, propanolamine at a boiling point of 187.5 ℃, isopropanolamine at a boiling point of 159.5 ℃. From the above data, the boiling points of ethanolamine, propanolamine and isopropanolamine are lower than those of NMP, and the separation is carried out as a light component of the rectifying tower relative to NMP products. And the boiling point of the diethanolamine and the triethanolamine is higher than that of NMP, and the diethanolamine and the triethanolamine are separated as heavy components of a rectifying tower relative to NMP products. The propanolamine is more special, the boiling point of the propanolamine is 96 ℃ under the negative pressure condition of 2kpa, the boiling point of the NMP is 89 ℃, and the propanolamine is separated as a heavy component of a rectifying tower relative to the NMP product under the condition of negative pressure rectification. The NMP recovery liquid generally contains the amine additives with mass fraction concentration of about 0.001-0.006. The boiling points of diethanolamine, triethanolamine and isopropanolamine are greatly different from those of NMP, and the qualified NMP product can be obtained by changing the operation conditions of the existing rectifying device. However, the boiling points of ethanolamine and propanolamine are too close to that of NMP, the concentration of the alcohol amine additive is very low, a large amount of energy is consumed for separating a small amount of impurities by the rectifying tower, and the operating conditions of the rectifying tower are different due to different alcohol amine additives, so that a unified device cannot be used for adapting to the working conditions of different additives. With the development of the semiconductor industry, the NMP used in the semiconductor industry has higher and higher requirements on free amine, and even 1ppm is required, and the common rectification mode can only achieve 20-30 ppm, which is different fr