NMP waste liquid refining and purifying system based on open type heat pump

By adopting open heat pump technology in the NMP waste liquid purification and purification system, heat recovery and preheating is used to use the compressor's heat-raising gas phase to solve the problems of low heat recovery and insufficient heating in the existing system, and energy consumption is achieved and the improvement of heat recovery.

CN222181869UActive Publication Date: 2024-12-17AEROSPACE GUOHUA RESOURCES RECYCLING (HUZHOU) CO LTD
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Patent Information

Application Number
CN202420766412.5
Authority / Receiving Office
CN · China
Patent Type
Utility models(China)
Current Assignee / Owner
Filing Date
2024-04-15
Publication Date
2024-12-17
Estimated Expiration
2034-04-15

AI Technical Summary

Technical Problem

The existing NMP waste liquid distillation purification system has problems such as low waste heat recovery and insufficient heating, resulting in high energy consumption.

Method used

Using an open heat pump-based system, the compressor compresses the gas phase on the top of the refining tower and uses the heat-raising gas phase directly to the heat exchange reboiler, replacing the traditional steam heat exchange reboiler, improving the heat recovery utilization rate, and Reduce steam consumption by setting up a preheater to recover heat from the steam reboiler.

Benefits of technology

It improves heat recovery and utilization, reduces energy consumption, reduces steam consumption of refined towers, and has application advantages in areas where electricity is cheaper than steam.

✦ Generated by Eureka AI based on patent content.

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Abstract

The utility model provides an open type heat pump-based NMP (N-Methyl Pyrrolidone) waste liquid refining and purifying system, which comprises a first-stage dehydrating tower, a second-stage dehydrating tower and a refining tower which are sequentially connected in series, a discharge port of the first-stage dehydrating tower is connected with a feed port of the second-stage dehydrating tower, a discharge port of the second-stage dehydrating tower is connected with a feed port of the refining tower, and the open type heat pump-based NMP waste liquid refining and purifying system further comprises a compressor and a heat pump, the condenser is mounted at the top of the refining tower, and an inlet is communicated with a top outlet of the refining tower; the heat exchange reboiler is mounted at the kettle bottom of the refining tower, and a shell pass inlet of the heat exchange reboiler is communicated with an outlet of the compressor; an inlet of the rectification reflux tank is communicated with a shell pass outlet of the heat exchange reboiler, and an outlet of the rectification reflux tank is provided with a rectification reflux branch and an output branch. The compressor is arranged at the top of the refining tower to compress a gas phase at the top of the refining tower to heat the gas phase, and then the heated gas phase is directly communicated to the shell pass of the heat exchange reboiler to exchange heat with the kettle bottom of the refining tower, so that the heat loss is small, the function of improving the heat recovery rate is realized, and the problem of high energy consumption of NMP rectification recovery is solved.
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Description

Technical Field

[0001] The utility model relates to the technical field of chemical industry, in particular to an NMP waste liquid refining and purification system based on an open heat pump. Background Art

[0002] N-Methylpyrrolidone, referred to as NMP, is an organic substance with good chemical and thermal stability, high polarity, low volatility, and infinite miscibility with water and many organic solvents. It is used in the production of high-precision electronics, circuit boards, and lithium batteries. NMP is toxic, and long-term contact or inhalation of high-concentration NMP waste gas will cause certain harm to the health of operators and will also cause certain pollution to the environment, so NMP needs to be recycled.

[0003] Chinese patent CN116477781B discloses a distillation and purification system and process for NMP recovery waste liquid, the system comprising: a pre-treatment unit, which includes a first heat exchanger, a gas-liquid separation tank, a second heat exchanger, and a buffer tank; a secondary distillation unit, which includes a first distillation tower and a second distillation tower arranged in series; the first distillation tower is provided with a gas phase feed port and a liquid phase feed port; the distillation and purification system for NMP recovery waste liquid provided by the invention realizes the recovery and utilization of waste heat of the distillation and purification unit, and further realizes the efficient distillation and purification of NMP recovery waste liquid.

[0004] However, this technical solution has the following problems: first, a waste heat recovery unit is provided, and the heat of the gas phase at the top of the second distillation tower must first be absorbed by the waste heat recovery unit, and then the waste heat recovery unit exchanges heat with the second heat exchanger. The structure is complicated, and part of the heat will be lost in the waste heat recovery unit, and the heat recovery rate is low. Second, the steam source of the first reboiler is also the waste heat recovery unit, which may result in insufficient heating. Utility Model Content

[0005] The utility model aims to solve the shortcomings of the prior art and provide an NMP waste liquid refining and purification system based on an open heat pump. A compressor is installed at the top of a refining tower to compress the gas phase at the top of the refining tower to increase its temperature, and then the heated gas phase is directly connected to the shell side of a heat exchange reboiler to exchange heat with the bottom of the refining tower. The heat loss is small, the function of improving the heat recovery rate is achieved, and the problem of high energy consumption of NMP distillation recovery is solved.

[0006] In order to achieve the above purpose, the utility model provides the following technical solutions:

[0007] A NMP waste liquid refining and purification system based on an open heat pump, comprising a primary dehydration tower, a secondary dehydration tower and a refining tower connected in series, wherein the discharge port of the primary dehydration tower is connected to the feed port of the secondary dehydration tower, the discharge port of the secondary dehydration tower is connected to the feed port of the refining tower, a first condenser is installed on the top of the primary dehydration tower, a second condenser is installed on the top of the secondary dehydration tower, and further comprising:

[0008] A compressor is installed at the top of the refining tower, and its inlet is connected to the outlet at the top of the refining tower;

[0009] The heat exchange reboiler is installed at the bottom of the refining tower, and its shell side inlet is connected to the compressor outlet.

[0010] As a preferred embodiment, it also includes:

[0011] A first steam reboiler is installed at the bottom of the first-stage dehydration tower;

[0012] A second steam reboiler is installed at the bottom of the secondary dehydration tower;

[0013] The heat sources of the first steam reboiler and the second steam reboiler are steam.

[0014] Preferably, the primary dehydration tower comprises a waste liquid inlet, the waste liquid inlet is connected to an input pipeline, and the input pipeline is sequentially installed with a first preheater and a second preheater.

[0015] Preferably, the shell side inlet of the first preheater is connected to the shell side outlet of the heat exchange reboiler, the shell side outlet of the first preheater is connected to a distillation reflux tank, and the distillation reflux tank outlet is provided with a distillation reflux branch and an output branch.

[0016] Preferably, the shell side outlets of the first steam reboiler and the second steam reboiler are connected to the shell side inlet of the second preheater, and the waste liquid is preheated in the second preheater by using steam condensate.

[0017] As a preference, a first reflux tank is also installed on the top of the primary dehydration tower, the tube side inlet of the first condenser is connected to the top of the primary dehydration tower, and the tube side outlet thereof is connected to the inlet of the first reflux tank.

[0018] As a preferred embodiment, the first reflux tank outlet comprises:

[0019] A first reflux branch connected to the top of the primary dehydration tower;

[0020] External discharge branch, discharges condensed waste liquid.

[0021] As a preference, a second reflux tank is also installed on the top of the secondary dehydration tower, the tube side inlet of the second condenser is connected to the top of the secondary dehydration tower, and the tube side outlet thereof is connected to the inlet of the second reflux tank.

[0022] As a preferred embodiment, the second reflux tank outlet comprises:

[0023] A second reflux branch connected to the top of the secondary dehydration tower;

[0024] The condensate recovery branch is connected to the input pipeline.

[0025] As a preference, a filter is installed before the first preheater.

[0026] The beneficial effects of the utility model are:

[0027] (1) The utility model replaces the original steam heat exchange reboiler by installing a heat exchange reboiler at the bottom of the refining tower, and its heat source is the gas phase at the top of the refining tower after being compressed and heated by a compressor, and the heat of the gas phase is directly recovered, with less heat loss and high recovery rate, thereby reducing the steam consumption of the refining tower.

[0028] (2) The utility model further improves the heat recovery rate of the utility model by providing a first preheater to recover the heat of the heat exchange reboiler and providing a second preheater to recover the heat of the first steam reboiler and the second steam reboiler. In addition, preheating the NMP waste liquid entering the primary dehydration tower can reduce the steam consumption of the first steam reboiler, thereby reducing the energy consumption of the utility model.

[0029] (3) The utility model heats the gas phase at the top of the refining tower by arranging a compressor, which has obvious application advantages in areas where electricity is cheaper than steam. BRIEF DESCRIPTION OF THE DRAWINGS

[0030] Figure 1 This is a schematic diagram of the structure of the process system of the utility model. DETAILED DESCRIPTION

[0031] The following will be combined with the drawings in the embodiments of the utility model to clearly and completely describe the technical solutions in the embodiments of the utility model. Obviously, the described embodiments are only part of the embodiments of the utility model, not all of the embodiments. Based on the embodiments of the utility model, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the utility model.

[0032] In the description of the present utility model, it should be understood that the terms "center", "longitudinal", "lateral", "length", "width", "thickness", "up", "down", "front", "back", "left", "right", "vertical", "horizontal", "top", "bottom", "inside", "outside", "clockwise", "counterclockwise" and the like indicate positions or positional relationships based on the positions or positional relationships shown in the accompanying drawings, and are only for the convenience of describing the present utility model and simplifying the description, rather than indicating or implying that the equipment or elements referred to must have a specific orientation, be constructed and operated in a specific orientation, and therefore cannot be understood as limiting the present utility model. In addition, the terms "first" and "second" are only used for descriptive purposes, and cannot be understood as indicating or implying relative importance or implicitly indicating the number of technical features indicated. Therefore, the features defined as "first" and "second" may explicitly or implicitly include one or more of the features. In the description of the present utility model, the meaning of "multiple" is two or more, unless otherwise clearly and specifically defined.

[0033] Example

[0034] like Figure 1 As shown, this embodiment provides a NMP waste liquid refining and purification system based on an open heat pump, comprising a primary dehydration tower 1, a secondary dehydration tower 2 and a refining tower 3 connected in series, the discharge port of the primary dehydration tower 1 is connected to the feed port of the secondary dehydration tower 2, the discharge port of the secondary dehydration tower 2 is connected to the feed port of the refining tower 3, a first condenser 15 is installed on the top of the primary dehydration tower 1, and a second condenser 21 is installed on the top of the secondary dehydration tower 2, and also includes: a compressor 4, installed on the top of the refining tower 3, its inlet is connected to the outlet of the top of the refining tower 3, and the compressor 4 is arranged to heat the gas phase at the top of the refining tower 3, which has obvious application advantages in areas where electricity is cheaper than steam; a heat exchange reboiler 5, installed at the bottom of the refining tower 3, and its shell side inlet is connected to the outlet of the compressor 4. The gas phase at the top of the refining tower 3 enters the heat exchange reboiler 5 after being compressed and heated by the compressor 4, and exchanges heat with the liquid phase at the bottom of the refining tower 3.

[0035] It should be noted that, in the present embodiment, the refining tower 3 is preferably a product tower, the feed temperature of the refining tower 3 is 140-150°C, the bottom temperature after heating by the heat exchange reboiler 5 is 160-170°C, the top gas phase temperature is 145-155°C, and the compressor 4 is provided to compress the top gas phase to improve its grade so that it reaches a pressure of 1.0 MPa and a temperature of 180°C.

[0036] A heat exchange reboiler 5 is installed at the bottom of the refining tower 3 to replace the original steam heat exchange reboiler, and its heat source is the gas phase at the top of the refining tower 3 after compression and temperature increase by the compressor 4. The heat of the gas phase is directly recovered, with less heat loss and high recovery rate, thereby reducing the steam consumption of part of the refining tower 3.

[0037] like Figure 1 As shown, it also includes: a first steam reboiler 7, installed at the bottom of the first dehydration tower 1; a second steam reboiler 8, installed at the bottom of the second dehydration tower 2; the heat source of the first steam reboiler 7 and the second steam reboiler 8 is steam.

[0038] The primary dehydration tower 1 includes a waste liquid inlet 11, which is connected to an input pipeline 12, and the input pipeline 12 is sequentially installed with a first preheater 13 and a second preheater 14. The shell side inlet of the first preheater 13 is connected to the shell side outlet of the heat exchange reboiler 5, and the waste liquid in the first preheater 13 is preheated by using the high temperature gas phase component of the heat exchange reboiler 5. The shell side outlet of the first preheater 13 is connected to a rectification reflux tank 6, and the outlet of the rectification reflux tank 6 is provided with a rectification reflux branch 61 and an output branch 62. The qualified concentration of the condensate after heat exchange is output as NMP product through the output branch 62, and the unqualified concentration is returned to the top of the refining tower 3 through the rectification reflux branch 61. The shell side outlets of the first steam reboiler 7 and the second steam reboiler 8 are connected to the shell side inlet of the second preheater 14, and the waste liquid is preheated in the second preheater 14 by using steam condensate.

[0039] By setting the first preheater 13 to recover the heat of the heat exchange reboiler 5, and setting the second preheater 14 to recover the heat of the first steam reboiler 7 and the second steam reboiler 8, the heat recovery rate of the utility model is further improved, and preheating the 1NMP waste liquid entering the primary dehydration tower can reduce the steam consumption of the first steam reboiler 7, thereby reducing the energy consumption of the utility model.

[0040] A first reflux tank 16 is also installed at the top of the primary dehydration tower 1, and the tube-side inlet of the first condenser 15 is connected to the top of the primary dehydration tower 1, and the tube-side outlet thereof is connected to the inlet of the first reflux tank 16. The outlet of the first reflux tank 16 includes: a first reflux branch 161 connected to the top of the primary dehydration tower 1; and an external discharge branch 162 for discharging condensed waste liquid.

[0041] A second reflux tank 22 is also installed on the top of the secondary dehydration tower 2, and the pipe side inlet of the second condenser 21 is connected to the top of the secondary dehydration tower 2, and its pipe side outlet is connected to the inlet of the second reflux tank 22. The outlet of the second reflux tank 22 includes: a second reflux branch 221, which is connected to the top of the secondary dehydration tower 2; and a condensate recovery branch 222, which is connected to the input pipeline 12 and re-enters the primary dehydration tower 1 after mixing with the NMP waste liquid.

[0042] A filter 17 is installed before the first preheater 13 to filter impurities in the NMP waste liquid before it enters the first preheater 13 to prevent scaling of the inner tube wall of the first preheater 13 from affecting the transmission of the NMP waste liquid.

[0043] The above description is only a preferred embodiment of the present invention and is not intended to limit the present invention. Any modifications, equivalent substitutions and improvements made within the spirit and principles of the present invention should be included in the protection scope of the present invention.

Claims

1. A NMP waste liquid refining and purification system based on an open heat pump, comprising a primary dehydration tower, a secondary dehydration tower and a refining tower connected in series, wherein the discharge port of the primary dehydration tower is connected to the feed port of the secondary dehydration tower, the discharge port of the secondary dehydration tower is connected to the feed port of the refining tower, a first condenser is installed on the top of the primary dehydration tower, and a second condenser is installed on the top of the secondary dehydration tower, characterized in that: Also includes: A compressor is installed at the top of the refining tower, and its inlet is connected to the outlet at the top of the refining tower; The heat exchange reboiler is installed at the bottom of the refining tower, and its shell side inlet is connected to the compressor outlet.

2. A NMP waste liquid refining and purification system based on an open heat pump according to claim 1, characterized in that: Also includes: A first steam reboiler is installed at the bottom of the first-stage dehydration tower; A second steam reboiler is installed at the bottom of the secondary dehydration tower; The heat sources of the first steam reboiler and the second steam reboiler are steam.

3. A NMP waste liquid refining and purification system based on an open heat pump according to claim 2, characterized in that, The primary dehydration tower comprises a waste liquid inlet, the waste liquid inlet is connected with an input pipeline, and the input pipeline is sequentially installed with a first preheater and a second preheater.

4. A NMP waste liquid refining and purification system based on an open heat pump according to claim 3, characterized in that: The shell side inlet of the first preheater is connected to the shell side outlet of the heat exchange reboiler, the shell side outlet of the first preheater is connected to a distillation reflux tank, and the distillation reflux tank outlet is provided with a distillation reflux branch and an output branch.

5. A NMP waste liquid refining and purification system based on an open heat pump according to claim 4, characterized in that: The shell side outlets of the first steam reboiler and the second steam reboiler are connected to the shell side inlet of the second preheater, and the waste liquid is preheated in the second preheater by using steam condensate.

6. A NMP waste liquid refining and purification system based on an open heat pump according to claim 1, characterized in that: A first reflux tank is also installed on the top of the primary dehydration tower. The first condenser tube side inlet is connected to the top of the primary dehydration tower, and the tube side outlet is connected to the first reflux tank inlet.

7. A NMP waste liquid refining and purification system based on an open heat pump according to claim 6, characterized in that: The first reflux tank outlet comprises: A first reflux branch connected to the top of the primary dehydration tower; External discharge branch, discharges condensed waste liquid.

8. The NMP waste liquid refining and purification system based on an open heat pump according to claim 3, characterized in that: A second reflux tank is also installed on the top of the secondary dehydration tower. The tube side inlet of the second condenser is connected to the top of the secondary dehydration tower, and the tube side outlet is connected to the inlet of the second reflux tank.

9. A NMP waste liquid refining and purification system based on an open heat pump according to claim 8, characterized in that: The second reflux tank outlet comprises: A second reflux branch connected to the top of the secondary dehydration tower; The condensate recovery branch is connected to the input pipeline.

10. The NMP waste liquid refining and purification system based on an open heat pump according to claim 3, characterized in that: A filter is installed before the first preheater.