Low-boiling-point solvent and DMF (Dimethyl Formamide) recovery device

Abstract

The utility model provides a device for recovering a low-boiling-point solvent and DMF (Dimethyl Formamide), which is characterized in that the low-boiling-point solvent and the DMF are thoroughly separated from DMF waste liquid through a low-pressure tower, a high-pressure tower and a DMF separating tower, and the DMF is obtained at a heavy component outlet at the bottom of the DMF separating tower. Light components at the top of the high-pressure tower enter the low-pressure tower reboiler to serve as a heat source of the low-pressure tower reboiler, so that the heat of the light components in the high-pressure tower is fully utilized, and the energy consumption is reduced.

Description

Technical Field

[0001] The utility model belongs to the technical field of DMF recovery, and in particular relates to a recovery device for a low boiling point solvent and DMF. Background Art

[0002] Dimethylformamide (DMF) has a strong solubility and is miscible in most organic solvents and water. It is not only a widely used chemical raw material, but also a commonly used chemical reaction solvent. It is used to produce chlordimeform in the pesticide industry and to synthesize vitamin B6, N-formylsarcolysin, methoxy mustard, cyclohexanenitrosourea, etc. in the pharmaceutical industry. Although DMF is a "universal solvent", the DMF waste liquid containing low-boiling point solvents generated during use is not easy to recycle, and direct discharge is harmful to the environment and wastes resources.

[0003] At present, the recovery method of DMF generally adopts distillation. For the recovery of low-concentration DMF, the current distillation equipment and process are very complex and the operating cost is high.

[0004] Therefore, in order to realize the comprehensive utilization of resources and improve market competitiveness, developing a recovery device for low boiling point solvents and DMF is an urgent problem to be solved. Utility Model Content

[0005] The utility model aims to provide a recovery device for a low boiling point solvent and DMF. The recovery device in the utility model has high separation efficiency, low solvent loss, high recovery rate and low energy consumption.

[0006] The present invention provides a low boiling point solvent and DMF recovery device, comprising a low pressure tower, a high pressure tower, a DMF separation tower, a low boiling point solvent product tank and a DMF product tank;

[0007] The low-pressure tower is provided with a DMF waste liquid inlet, the bottom heavy component outlet of the low-pressure tower is connected to the inlet of the high-pressure tower, the bottom heavy component outlet of the high-pressure tower is connected to the inlet of the DMF separation tower, and the bottom heavy component outlet of the DMF separation tower is connected to the DMF product tank;

[0008] The light component outlet at the top of the low-pressure tower is connected to the inlet of the low-pressure tower reflux tank via the low-pressure tower condenser, the light component outlet at the top of the high-pressure tower is connected to the heat medium inlet of the low-pressure tower reboiler, and the heat medium outlet of the low-pressure tower reboiler is connected to the inlet of the high-pressure tower reflux tank;

[0009] The bottom outlet of the low-pressure tower reflux tank is connected to the top reflux liquid inlet of the low-pressure tower and the inlet of the low-boiling point solvent product tank respectively through the low-pressure tower reflux pump, the bottom outlet of the high-pressure tower reflux tank is connected to the top reflux liquid inlet of the high-pressure tower and the inlet of the low-boiling point solvent product tank respectively through the high-pressure tower reflux pump, and the bottom outlet of the separation tower reflux tank is connected to the top reflux liquid inlet of the DMF separation tower and the inlet of the low-boiling point solvent product tank respectively through the DMF separation tower reflux pump.

[0010] Preferably, a low-pressure tower preheater is provided before the DMF waste liquid inlet of the low-pressure tower.

[0011] The bottom heavy component outlet of the DMF separation tower is respectively connected to the feed inlet of the DMF separation tower reboiler and the heat medium inlet of the low-pressure tower preheater, and the heat medium outlet of the low-pressure tower preheater is connected to the inlet of the DMF product tank.

[0012] Preferably, it also includes a high-pressure tower condenser,

[0013] The light component outlet at the top of the high-pressure tower is directly connected to the inlet of the high-pressure tower reflux tank and the reboiler of the low-pressure tower respectively;

[0014] The heat medium outlet of the low-pressure tower reboiler is connected to the inlet of the high-pressure tower reflux tank, and the top outlet of the high-pressure tower reflux tank is connected to the inlet of the high-pressure tower condenser;

[0015] The liquid phase outlet of the high-pressure tower condenser is communicated with the inlet of the high-pressure tower reflux tank.

[0016] Preferably, a separation tower buffer tank is also provided;

[0017] The heavy component outlet at the bottom of the high-pressure tower is connected to the inlet of the separation tower buffer tank, and the outlet of the separation tower buffer tank is connected to the inlet of the DMF separation tower via a material transfer pump.

[0018] Preferably, the heat medium outlet of the low-pressure tower reboiler is connected to the inlet of the high-pressure tower condenser, and the outlet of the high-pressure tower condenser is connected to the inlet of the high-pressure tower reflux tank.

[0019] Preferably, a low-boiling-point solvent buffer tank and a low-boiling-point solvent refining tower are provided before the inlet of the low-boiling-point solvent product tank;

[0020] The inlet of the low-boiling point solvent buffer tank is respectively connected to the bottom outlet of the low-pressure tower reflux tank, the bottom outlet of the high-pressure tower reflux tank and the bottom outlet of the separation tower reflux tank, the outlet of the low-boiling point solvent buffer tank is connected to the inlet of the low-boiling point solvent refining tower, and the bottom outlet of the low-boiling point solvent refining tower is connected to the inlet of the low-boiling point solvent product tank.

[0021] Preferably, a phase separation tank is further provided, wherein the phase separation tank has an oil phase outlet and a water phase outlet;

[0022] The light component outlet at the top of the low boiling point solvent refining tower is connected to the inlet of the phase separation tank through the refining tower condenser, and the oil phase outlet of the phase separation tank is connected to the top inlet of the low boiling point solvent refining tower.

[0023] Preferably, a DMF evaporator is also provided;

[0024] The heavy component outlet at the bottom of the DMF separation tower is respectively connected to the feed port of the separation tower reboiler and the inlet of the DMF evaporator, and the light component outlet of the DMF evaporator is connected to the inlet of the DMF product tank through the evaporator condenser.

[0025] Preferably, the low-pressure tower reboiler is selected from a falling film reboiler, a thermosyphon reboiler, a forced circulation reboiler, and a kettle reboiler.

[0026] Preferably, a vacuum pump is also included, and the low-pressure tower condenser, the DMF separation tower condenser, and the refining tower condenser are all connected to the vacuum pump through a vacuum pipeline.

[0027] The utility model provides a recovery device for low-boiling point solvent and DMF, comprising a low-pressure tower, a high-pressure tower, a DMF separation tower, a low-boiling point solvent product tank and a DMF product tank; the low-pressure tower is provided with a DMF waste liquid inlet, the tower bottom heavy component outlet of the low-pressure tower is connected with the inlet of the high-pressure tower, the tower bottom heavy component outlet of the high-pressure tower is connected with the inlet of the DMF separation tower, the heavy component outlet of the DMF separation tower is connected with the DMF product tank; the tower top light component outlet of the low-pressure tower is connected with the inlet of the low-pressure tower reflux tank via a low-pressure tower condenser, the tower top light component outlet of the high-pressure tower is connected with the low-pressure tower reflux tank, and the tower top light component outlet of the high-pressure tower is connected with the low-pressure tower reflux tank. The heat medium inlet of the high-pressure tower reboiler is connected, the heat medium outlet of the low-pressure tower reboiler is connected with the inlet of the high-pressure tower reflux tank, the bottom outlet of the low-pressure tower reflux tank is connected with the top reflux liquid inlet of the low-pressure tower and the inlet of the low-boiling point solvent product tank respectively through the low-pressure tower reflux pump, the bottom outlet of the high-pressure tower reflux tank is connected with the top reflux liquid inlet of the high-pressure tower and the inlet of the low-boiling point solvent product tank respectively through the high-pressure tower reflux pump, and the bottom outlet of the separation tower reflux tank is connected with the top reflux liquid inlet of the DMF separation tower and the inlet of the low-boiling point solvent product tank respectively through the DMF separation tower reflux pump.

[0028] Compared with the prior art, the utility model is beneficial in that:

[0029] The recovery device provided by the utility model realizes the separation and recovery of the low boiling point solvent and DMF by sequentially connecting a low-pressure tower, a high-pressure tower and a DMF separation tower in series. The three towers separate the low boiling point solvent and DMF, the separation process is simple, and the solvent loss is reduced.

[0030] The high-pressure and low-pressure towers use heat-integrated energy-saving technology, using the gas phase at the top of the high-pressure tower as the heat source for the low-pressure tower reboiler. While heating the material at the bottom of the low-pressure tower, the gas phase at the top of the high-pressure tower is condensed, reducing equipment investment and process energy consumption. The dual-effect distillation of the low-pressure tower and the high-pressure tower not only reduces the energy consumption of low-boiling point solvent recovery, but also recovers high-purity low-boiling point solvent.

[0031] The heavy components at the bottom of the DMF separation tower are used as the heat medium of the low-pressure tower preheater to preheat the DMF waste liquid containing low-boiling point solvents. The preheated DMF waste liquid containing low-boiling point solvents then enters the low-pressure tower for distillation, thereby improving energy utilization and reducing energy consumption.

[0032] The establishment of a low-boiling-point solvent refining tower enables the recovery of high-purity low-boiling-point solvents; the establishment of a DMF evaporator enables the recovery of high-purity DMF.

[0033] The reflux tank is provided with a water phase outlet which also functions as a phase separation tank, so that the recovery device can separate the water phase while separating the low boiling point solvent and DMF, and recover the low boiling point solvent and DMF from the DMF waste liquid containing water and the low boiling point solvent. BRIEF DESCRIPTION OF THE DRAWINGS

[0034] In order to more clearly illustrate the embodiments of the utility model or the technical solutions in the prior art, the drawings required for use in the embodiments or the description of the prior art will be briefly introduced below. Obviously, the drawings in the following description are only embodiments of the utility model. For ordinary technicians in this field, other drawings can be obtained based on the provided drawings without paying creative work.

[0035] Figure 1 A schematic diagram of the structure of the device used in Example 1 of the utility model;

[0036] Figure 2 A schematic diagram of the structure of the device used in Example 2 of the present utility model;

[0037] Figure 3 A schematic diagram of the structure of the device used in Example 3 of the present utility model;

[0038] Figure 4 A schematic diagram of the structure of the device used in Example 4 of the utility model;

[0039] Figure 5 A schematic diagram of the structure of the device used in Example 5 of the utility model;

[0040] Figure 6 A schematic diagram of the structure of the device used in Example 6 of the present utility model;

[0041] Figure 7 A schematic diagram of the structure of the device used in Example 7 of the present utility model;

[0042] in, Figures 1 to 7 Among them, 1 low-pressure tower, 1-1 low-pressure tower condenser, 1-2 low-pressure tower reflux tank, 1-3 low-pressure tower reflux pump, 1-4 low-pressure tower reboiler, 2 high-pressure tower, 2-1 high-pressure tower reflux tank, 2-2 high-pressure tower reflux pump, 2-3 high-pressure tower reboiler, 2-4 high-pressure tower condenser, 3DMF separation tower, 3-1 separation tower condenser, 3-2 separation tower reflux tank, 3-3DMF separation tower reflux pump, 3-4 separation tower reboiler, 4 low-boiling point solvent product tank, 5DMF product tank, 6 low-pressure tower preheater, 7 separation tower buffer tank, 8 transfer pump, 9 low-boiling point solvent buffer tank, 10 low-boiling point solvent refining tower, 11 refining tower condenser, 12 phase separation tank, 13 vacuum pump, 14DMF evaporator, 15 evaporator condenser. DETAILED DESCRIPTION

[0043] The utility model provides a low boiling point solvent and DMF recovery device, comprising a low pressure tower 1, a high pressure tower 2, a DMF separation tower 3, a low boiling point solvent product tank 4 and a DMF product tank 5;

[0044] like Figure 1 As shown, the low-pressure tower 1 is provided with a DMF waste liquid inlet, the bottom heavy component outlet of the low-pressure tower 1 is connected to the inlet of the high-pressure tower 2, the bottom heavy component outlet of the high-pressure tower 2 is connected to the inlet of the DMF separation tower 3, and the heavy component outlet of the DMF separation tower 3 is connected to the DMF product tank 5;

[0045] The light component outlet at the top of the low-pressure tower 1 is connected to the inlet of the low-pressure tower reflux tank 1-2 through the low-pressure tower condenser 1-1, the light component outlet at the top of the high-pressure tower 2 is connected to the heat medium inlet of the low-pressure tower reboiler 1-4, and the heat medium outlet of the low-pressure tower reboiler 1-4 is connected to the inlet of the high-pressure tower reflux tank 2-1.

[0046] The bottom outlet of the low-pressure tower reflux tank 1-2 is connected to the top reflux liquid inlet of the low-pressure tower 1 and the inlet of the low-boiling point solvent product tank 4 respectively through the low-pressure tower reflux pump 1-3, the bottom outlet of the high-pressure tower reflux tank 2-1 is connected to the top reflux liquid inlet of the high-pressure tower 2 and the inlet of the low-boiling point solvent product tank 4 respectively through the high-pressure tower reflux pump 2-2, and the bottom outlet of the separation tower reflux tank 3-2 is connected to the top reflux liquid inlet of the DMF separation tower 3 and the inlet of the low-boiling point solvent product tank 4 respectively through the DMF separation tower reflux pump 3-3.

[0047] In the present invention, the working pressure of the "low-pressure tower" is ≤100 kPa, and the working pressure of the "high-pressure tower" is >100 kPa.

[0048] The recovery device provided by the utility model is used for recovering low boiling point solvent and DMF in DMF waste liquid, wherein the low boiling point solvent is one or more of dichloromethane, dichloroethane and ethyl acetate. The DMF waste liquid containing low boiling point solvent first enters the low pressure tower 1 for rectification and separation, and the light component containing low boiling point solvent is separated at the top of the tower. The heavy component at the bottom of the low pressure tower 1 enters the high pressure tower 2 for further rectification and separation, and the light component containing low boiling point solvent is separated twice at the top of the high pressure tower 2. The heavy component at the bottom of the high pressure tower 2 enters the DMF separation tower 3, and the light component containing low boiling point solvent is separated three times at the top of the DMF separation tower 3. The low boiling point solvent and DMF are completely separated through the three towers of the low pressure tower 1, the high pressure tower 2 and the DMF separation tower 3, and DMF is obtained at the heavy component outlet at the bottom of the DMF separation tower 3. The light component at the top of the high pressure tower 2 enters the low pressure tower reboiler 1-4 as the heat source of the low pressure tower reboiler, which makes full use of the heat of the light component of the high pressure tower 2 and reduces energy consumption.

[0049] In order to improve the separation efficiency and recover the low-boiling point solvent, in the utility model, the light components entering the low-pressure tower reflux tank 1-2 are partially transported to the top reflux of the low-pressure tower 1 through the low-pressure tower reflux pump 1-3, and partially transported to the low-boiling point solvent product tank 4; the light components entering the high-pressure tower reflux tank 2-1 are partially transported to the top reflux of the high-pressure tower 2 through the high-pressure tower reflux pump 2-2, and partially transported to the low-boiling point solvent product tank 4; the light components entering the separation tower reflux tank 3-2 are partially transported to the top reflux of the DMF separation tower 3 through the DMF separation tower reflux pump 3-3, and partially transported to the low-boiling point solvent product tank 4.

[0050] In one embodiment of the present invention, Figure 2 As shown, a low-pressure tower preheater 6 is provided at the front end of the feed port of the low-pressure tower 1, and the bottom heavy component outlet of the DMF separation tower 3 is respectively connected to the feed port of the separation tower reboiler 3-4 and the heat medium inlet of the low-pressure tower preheater 6, and the heat medium outlet of the low-pressure tower preheater 6 is connected to the inlet of the DMF product tank 5. Part of the bottom heavy components of the DMF separation tower 3 are used as the heat medium of the low-pressure tower preheater 6 to preheat the DMF waste liquid containing the low-boiling point solvent, and the preheated DMF waste liquid containing the low-boiling point solvent enters the low-pressure tower 1 for rectification, thereby improving the utilization rate of energy and reducing energy consumption.

[0051] In order to further reduce the loss of low boiling point solvent, in one embodiment of the present invention, a high pressure tower condenser 2-4 is further provided.

[0052] like Figure 3As shown, the heat medium outlet of the low-pressure tower reboiler 1-4 is connected to the inlet of the high-pressure tower condenser 2-4, and the liquid phase outlet of the high-pressure tower condenser 2-4 is connected to the inlet of the high-pressure tower reflux tank 2-1. All the light components at the top of the high-pressure tower 2 are used as the heat medium of the low-pressure tower reboiler 1-4, firstly heat exchange with the DMF waste liquid containing the low-boiling point solvent, and then enter the high-pressure tower reflux tank 2-1 after condensation by the high-pressure tower condenser 2-4.

[0053] Further, the light component outlet of the tower top of the high-pressure tower 2 is also connected to the inlet of the high-pressure tower reflux tank 2-1, the heat medium outlet of the low-pressure tower reboiler 1-4 is connected to the inlet of the high-pressure tower reflux tank 2-1, and the top outlet of the high-pressure tower reflux tank 2-1 is connected to the inlet of the high-pressure tower condenser 2-4. The light component part of the tower top of the high-pressure tower 2 directly enters the high-pressure tower reflux tank 2-1, and part of it is used as the heat medium of the low-pressure tower reboiler 1-4, and enters the high-pressure tower reflux tank 2-1 after heat exchange with the DMF waste liquid containing the low-boiling point solvent in the low-pressure tower reboiler 1-4, and the gas phase escaping from the high-pressure tower reflux tank 2-1 enters the high-pressure tower condenser 2-4 for condensation.

[0054] In order to ensure the smooth operation of the device, in one embodiment of the present invention, a separation tower buffer tank 7 is also provided. Figure 4 As shown, the bottom heavy component outlet of the high-pressure tower 2 is connected to the inlet of the separation tower buffer tank 7, and the outlet of the separation tower buffer tank 7 is connected to the inlet of the DMF separation tower 3 via the transfer pump 8. The bottom heavy component of the high-pressure tower 2 enters the separation tower buffer tank 7 and is transported to the DMF separation tower 3 via the transfer pump 8 after the pressure fluctuation is buffered.

[0055] In order to further separate and obtain a high-purity low-boiling-point solvent, in one embodiment of the present invention, a low-boiling-point solvent buffer tank 9 and a low-boiling-point solvent refining tower 10 are sequentially arranged at the front end of the low-boiling-point solvent product tank 4, such as Figure 5 As shown, the bottom outlet of the low-pressure tower reflux tank 1-2 is connected to the top reflux liquid inlet of the low-pressure tower 1 and the inlet of the low-boiling point solvent buffer tank 9 respectively through the low-pressure tower reflux pump 1-3, the bottom outlet of the high-pressure tower reflux tank 2-1 is connected to the top reflux liquid inlet of the high-pressure tower 2 and the inlet of the low-boiling point solvent buffer tank 9 respectively through the high-pressure tower reflux pump 2-2, the bottom outlet of the separation tower reflux tank 3-2 is connected to the top reflux liquid inlet of the DMF separation tower 3 and the inlet of the low-boiling point solvent buffer tank 9 respectively through the DMF separation tower reflux pump 3-3, the outlet of the low-boiling point solvent buffer tank 9 is connected to the inlet of the low-boiling point solvent refining tower 10, and the bottom outlet of the low-boiling point solvent refining tower 10 is connected to the inlet of the low-boiling point solvent product tank 4.

[0056] The light components entering the low-pressure tower reflux tank 1-2 are partially transported to the top reflux of the low-pressure tower 1 through the low-pressure tower reflux pump 1-3, and partially transported to the low-boiling point solvent buffer tank 9. The light components entering the high-pressure tower reflux tank 2-1 are partially transported to the top reflux of the high-pressure tower 2 through the high-pressure tower reflux pump 2-2, and partially transported to the low-boiling point solvent buffer tank 9. The light components entering the separation tower reflux tank 3-2 are partially transported to the top reflux of the DMF separation tower 3 through the DMF separation tower reflux pump 3-3, and partially transported to the low-boiling point solvent buffer tank 9. The light components entering the low-boiling point solvent buffer tank 9 enter the low-boiling point solvent refining tower 10 for refining and purification, and the purified low-boiling point solvent flows into the low-boiling point solvent product tank 4, thereby obtaining a high-purity low-boiling point solvent.

[0057] In order to further purify the low boiling point solvent, in one embodiment of the present invention, a phase separation tank 12 is also provided. Figure 6 As shown, the light component outlet at the top of the low-boiling-point solvent refining tower 10 is connected to the inlet of the phase separation tank 12 via the refining tower condenser 11, the phase separation tank 12 has an oil phase outlet and a water phase outlet, and the oil phase outlet of the phase separation tank 12 is connected to the top inlet of the low-boiling-point solvent refining tower 10. The light component at the top of the low-boiling-point solvent refining tower 10 is condensed by the refining tower condenser 11 and enters the phase separation tank 12 for phase separation, and the oil phase separated from the water phase returns to the low-boiling-point solvent refining tower 10, thereby further purifying the low-boiling-point solvent.

[0058] For further recovery and obtaining highly purified DMF, in one embodiment of the utility model, as Figure 7 As shown, a DMF evaporator 14 is arranged at the front end of the DMF product tank 5, and the heavy component outlet at the bottom of the DMF separation tower 3 is respectively connected to the feed port of the separation tower reboiler 3-4 and the inlet of the DMF evaporator 14, and the light component outlet of the DMF evaporator 14 is connected to the inlet of the DMF product tank 5 via the evaporator condenser 15. The heavy component at the bottom of the DMF separation tower 3 is partially circulated back to the DMF separation tower 3 through the separation tower reboiler 3-4, and partially enters the DMF evaporator 14 for weight removal. The light component of the DMF evaporator 14 enters the DMF product tank 5 after being condensed by the evaporator condenser 15. The tar or other high-boiling-point components entrained by the heavy component at the bottom of the DMF separation tower 3 are removed by the DMF evaporator 14 to obtain high-purity DMF, thereby realizing the recycling of high-purity DMF.

[0059] In the utility model, the low-pressure tower preheater 6, the high-pressure tower condensers 2-4, the separation tower buffer tank 7, the low-boiling point solvent buffer tank 9, the low-boiling point solvent refining tower 10, the refining tower condenser 11, the phase separation tank 12, the DMF evaporator 14, the evaporator condenser 15, etc. can be used alone in the recovery device of the utility model as devices for further improving the effect, and two or more of the devices can also be combined and applied to the recovery device of the utility model. The utility model only provides the above-mentioned specific description for the cases of partial single use or partial combination use, but the remaining multiple combined use cases are also within the protection scope of the utility model.

[0060] In the utility model, the reflux tanks such as the low-pressure tower reflux tank 1-2, the high-pressure tower reflux tank 2-1, and the DMF separation tower reflux tank 3-2 all have water phase outlets, serving as both reflux tanks and phase separation tanks. When the DMF waste liquid containing a low-boiling point solvent contains water, it can be used to separate the water phase from the light component, thereby obtaining a high-purity low-boiling point solvent.

[0061] In the utility model, the reboilers such as low-pressure tower reboiler 1-4, high-pressure tower reboiler 2-3, and DMF separation tower reboiler 3-4 are all selected from one of a falling film reboiler, a thermal siphon reboiler, a forced circulation reboiler, and a kettle reboiler, among which the low-pressure tower reboiler 1-4 and the high-pressure tower reboiler 2-3 are preferably thermal siphon reboilers, and the separation tower reboiler 3-4 is preferably a falling film reboiler.

[0062] In the present utility model, a vacuum pump 13 is also provided, and the condensers such as the low-pressure tower condenser 1-1, the high-pressure tower condenser 2-4, the separation tower condenser 3-1, and the refining tower condenser 11 are all connected to the vacuum pump 13 through a vacuum pipeline, and the vacuum pump 13 is selected from one of an oil-free vertical vacuum pump, a reciprocating vacuum pump, a water ring vacuum pump, and a Roots vacuum pump. Preferably, the vacuum pump is selected from an oil-free vertical vacuum pump or a water ring vacuum pump. The vacuum pump 13 creates a negative pressure environment, reduces the boiling point of the solvent, reduces energy consumption, and reduces solvent loss.

[0063] In the present invention, unless otherwise clearly specified or limited, the connection mode between various units or devices should be understood in a broad sense. For example, it can be direct pipeline connection, or it can be connected through pipelines connected to conventional conveying, metering, control, and temporary storage equipment such as pumping equipment, metering equipment, valves and pipe fittings, intermediate tanks, etc. It can be fixed connection or detachable connection. For those skilled in the art, the specific meanings of the above terms in the present invention can be understood according to specific circumstances.

[0064] In the utility model, various components of the production device, such as the low-pressure tower, the high-pressure tower, the separation tower, the reflux tank, the reboiler, the condenser, the preheater, the buffer tank, the evaporator, the vacuum pump, as well as the pipes, valves, controllers, feed pumps, receiving tanks, etc. can be purchased from the market, but the entire reaction device cannot be purchased from the market and is not known to those skilled in the art.

[0065] 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 in 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.

[0066] Example 1

[0067] This embodiment provides a recovery device for low boiling point solvent and DMF, and its structural schematic diagram is as follows Figure 1 As shown, it includes a low-pressure tower 1, a low-pressure tower condenser 1-1, a low-pressure tower reflux tank 1-2, a low-pressure tower reflux pump 1-3, a low-pressure tower reboiler 1-4, a high-pressure tower 2, a high-pressure tower reflux tank 2-1, a high-pressure tower reflux pump 2-2, a high-pressure tower reboiler 2-3, a DMF separation tower 3, a separation tower condenser 3-1, a separation tower reflux tank 3-2, a DMF separation tower reflux pump 3-3, a separation tower reboiler 3-4, a low-boiling point solvent product tank 4, and a DMF product tank 5.

[0068] The light component outlet at the top of the low-pressure tower 1 is connected to the inlet of the low-pressure tower reflux tank 1-2 via the low-pressure tower condenser 1-1, the bottom outlet of the low-pressure tower reflux tank 1-2 is respectively connected to the top reflux liquid inlet of the low-pressure tower 1 and the inlet of the low-boiling point solvent product tank 4 via the low-pressure tower reflux pump 1-3, the heavy component outlet at the bottom of the low-pressure tower 1 is respectively connected to the inlet of the high-pressure tower 2 and the inlet of the low-pressure tower reboiler 1-4, the outlet of the low-pressure tower reboiler 1-4 is connected to the bottom inlet of the low-pressure tower 1, the light component outlet at the top of the high-pressure tower 2 is connected to the heat medium inlet of the low-pressure tower reboiler 1-4, the heat medium outlet of the low-pressure tower reboiler 1-4 is connected to the inlet of the high-pressure tower reflux tank 2-1, and the bottom outlet of the high-pressure tower reflux tank 2-1 is respectively connected to the top reflux liquid inlet of the high-pressure tower 2 via the high-pressure tower reflux pump 2-2. The high-pressure tower 2 is connected to the inlet of the DMF separation tower 3 and the inlet of the high-pressure tower reboiler 2-3, respectively. The outlet of the high-pressure tower reboiler 2-3 is connected to the inlet of the high-pressure tower 2 at the bottom. The outlet of the light component at the top of the DMF separation tower 3 is connected to the inlet of the separation tower reflux tank 3-2 via the separation tower condenser 3-1. The bottom outlet of the separation tower reflux tank 3-2 is connected to the inlet of the top reflux liquid of the DMF separation tower 3 and the inlet of the low-boiling point solvent product tank 4 via the DMF separation tower reflux pump 3-3. The heavy component outlet at the bottom of the DMF separation tower 3 is connected to the inlet of the DMF product tank 5 and the feed port of the separation tower reboiler 3-4, respectively. The outlet of the separation tower reboiler 3-4 is connected to the inlet of the bottom of the DMF separation tower 3.

[0069] The DMF waste liquid containing low-boiling point solvent enters the low-pressure tower 1 for distillation and separation. The light components at the top of the low-pressure tower 1 are condensed by the low-pressure tower condenser 1-1 and enter the low-pressure tower reflux tank 1-2. The light components in the low-pressure tower reflux tank 1-2 are partially transported to the top of the low-pressure tower 1 for reflux through the low-pressure tower reflux pump 1-3, and partially transported to the low-boiling point solvent product tank 4. Part of the heavy components at the bottom of the low-pressure tower 1 are heated by the low-pressure tower reboiler 1-4 and returned to the low-pressure tower 1. Part of the heavy components at the bottom of the tower enter the high-pressure tower 2 for distillation. The light components at the top of the high-pressure tower 2 for distillation enter the low-pressure tower reboiler 1-4. The light components after heat exchange in the low-pressure tower reboiler enter the high-pressure tower reflux tank 2-1. The high-pressure tower reflux The light components in tank 2-1 are partially transported to the top reflux of high-pressure tower 2 through high-pressure tower reflux pump 2-2, and partially transported to low-boiling point solvent product tank 4. Part of the heavy components at the bottom of high-pressure tower 2 are heated by high-pressure tower reboiler 2-3 and returned to high-pressure tower 2, and part of the heavy components at the bottom enter DMF separation tower 3 for distillation. The light components at the top of DMF separation tower 3 are condensed by separation tower condenser 3-1 and enter separation tower reflux tank 3-2. The light components in separation tower reflux tank 3-2 are partially transported to the top reflux of DMF separation tower 3 through DMF separation tower 3 reflux pump, and partially transported to low-boiling point solvent product tank 4. Part of the heavy components at the bottom of DMF separation tower 3 are DMF products.

[0070] Example 2

[0071] This embodiment provides a recovery device for low boiling point solvent and DMF, and its structural schematic diagram is as follows Figure 2 As shown, the difference from Example 1 is that in this embodiment, a low-pressure tower preheater 6 is provided at the front end of the feed inlet of the low-pressure tower 1.

[0072] On the basis of Example 1, the material outlet of the low-pressure tower preheater 6 is connected to the feed inlet of the low-pressure tower 1, part of the bottom heavy component outlet of the DMF separation tower 3 is connected to the heat medium inlet of the low-pressure tower preheater 6, and the heat medium outlet of the low-pressure tower preheater 6 is connected to the inlet of the DMF product tank 5.

[0073] The DMF waste liquid containing low-boiling point solvent and part of the heavy components at the bottom of the DMF separation tower 3 are heat exchanged in the low-pressure tower preheater 6 and then enter the low-pressure tower 1 for distillation. Part of the heavy components at the bottom of the DMF separation tower 3 serve as the heat medium of the low-pressure tower preheater 6 and flow into the DMF product tank 5 through the low-pressure tower preheater 6.

[0074] Example 3

[0075] This embodiment provides a recovery device for low boiling point solvent and DMF, and its structural schematic diagram is as follows Figure 3 As shown, the difference from Example 1 is that this embodiment is further provided with a high-pressure tower condenser 2-4.

[0076] On the basis of Example 1, the light component outlet at the top of the high-pressure tower 2 is respectively connected to the inlet of the high-pressure tower reflux tank 2-1 and the heat medium inlet of the low-pressure tower reboiler 1-4, the heat medium outlet of the low-pressure tower reboiler 1-4 is connected to the inlet of the high-pressure tower reflux tank 2-1, the top outlet of the high-pressure tower reflux tank 2-1 is connected to the inlet of the high-pressure tower condenser 2-4, the condensate outlet of the high-pressure tower condenser 2-4 is connected to the condensate inlet of the high-pressure tower reflux tank 2-1, and the bottom outlet of the high-pressure tower reflux tank 2-1 is respectively connected to the top reflux liquid inlet of the high-pressure tower 2 and the inlet of the low-boiling point solvent product tank 4 through the high-pressure tower reflux pump 2-2.

[0077] Part of the light components at the top of high-pressure tower 2 enters the high-pressure tower reflux tank 2-1, and part of the light components at the top of high-pressure tower 2 is used as the heat medium of the low-pressure tower reboiler 1-4. After heat exchange with the heavy components at the bottom of low-pressure tower 1 in the low-pressure tower reboiler 1-4, it enters the high-pressure tower reflux tank 2-1. The gas phase escaping from the high-pressure tower reflux tank 2-1 enters the high-pressure tower condenser 2-4, condenses and refluxes to the high-pressure tower reflux tank 2-1. The liquid in the high-pressure tower reflux tank 2-1 is partially transported to the top reflux of the high-pressure tower 2 through the high-pressure tower reflux pump 2-2, and partially transported to the low-boiling point solvent product tank 4.

[0078] Example 4

[0079] This embodiment provides a recovery device for low boiling point solvent and DMF, and its structural schematic diagram is as follows Figure 4 As shown, the difference from Example 1 is that this embodiment is further provided with a separation tower buffer tank 7 and a material transfer pump 8.

[0080] On the basis of Example 1, the heat medium outlet of the low-pressure tower reboiler 1-4 is connected to the inlet of the high-pressure tower condenser 2-4, the liquid phase outlet of the high-pressure tower condenser 2-4 is connected to the inlet of the high-pressure tower reflux tank 2-1, the bottom outlet of the high-pressure tower reflux tank 2-1 is respectively connected to the top reflux liquid inlet of the high-pressure tower 2 and the inlet of the low-boiling point solvent product tank 4 through the high-pressure tower reflux pump 2-2, the bottom heavy component outlet of the high-pressure tower 2 is respectively connected to the inlet of the separation tower buffer tank 7 and the inlet of the high-pressure tower reboiler 2-3, the outlet of the high-pressure tower reboiler 2-3 is connected to the bottom inlet of the high-pressure tower 2, the outlet of the separation tower buffer tank 7 is connected to the inlet of the DMF separation tower 3 through the transfer pump 8, and the low-pressure tower reflux tank 1-2, the high-pressure tower reflux tank 2-1, and the separation tower reflux tank 3-2 are all provided with water phase outlets.

[0081] All the light components at the top of the high-pressure tower 2 are used as heat media for the low-pressure tower reboiler 1-4. After heat exchange, they are condensed by the high-pressure tower condenser 2-4 and then enter the high-pressure tower reflux tank 2-1. The light components in the high-pressure tower reflux tank 2-1 are partially transported to the top of the high-pressure tower 2 for reflux through the high-pressure tower reflux pump 2-2, and partially transported to the low-boiling point solvent product tank 4. Some of the heavy components at the bottom of the high-pressure tower 2 enter the separation tower buffer tank 7 and are transported to the DMF separation tower 3 for distillation through the transfer pump. The low-pressure tower reflux tank 1-2, the high-pressure tower reflux tank 2-1, and the separation tower reflux tank 3-2 are used as both reflux tanks and phase separation tanks. When the DMF waste liquid of the low-boiling point solvent contains water, they are used to separate the water phase in the light components to obtain a high-purity low-boiling point solvent.

[0082] Example 5

[0083] This embodiment provides a recovery device for low boiling point solvent and DMF, and its structural schematic diagram is as follows Figure 5 As shown, the difference from Example 1 is that in this embodiment, a low boiling point solvent buffer tank 9 and a low boiling point solvent refining tower 10 are sequentially arranged at the front end of the low boiling point solvent product tank 4.

[0084] On the basis of Example 1, the bottom outlet of the low-pressure tower reflux tank 1-2 is connected to the top reflux liquid inlet of the low-pressure tower 1 and the inlet of the low-boiling point solvent buffer tank 9 respectively through the low-pressure tower reflux pump 1-3, the bottom outlet of the high-pressure tower reflux tank 2-1 is connected to the top reflux liquid inlet of the high-pressure tower 2 and the inlet of the low-boiling point solvent buffer tank 9 respectively through the high-pressure tower reflux pump 2-2, the bottom outlet of the separation tower reflux tank 3-2 is connected to the top reflux liquid inlet of the DMF separation tower 3 and the inlet of the low-boiling point solvent buffer tank 9 respectively through the DMF separation tower reflux pump 3-3, the outlet of the low-boiling point solvent buffer tank 9 is connected to the inlet of the low-boiling point solvent refining tower 10, and the bottom outlet of the low-boiling point solvent refining tower 10 is connected to the inlet of the low-boiling point solvent product tank 4.

[0085] The light components entering the low-pressure tower reflux tank 1-2 are partially transported to the top reflux of the low-pressure tower 1 through the low-pressure tower reflux pump 1-3, and partially transported to the low-boiling point solvent buffer tank 9. The light components entering the high-pressure tower reflux tank 2-1 are partially transported to the top reflux of the high-pressure tower 2 through the high-pressure tower reflux pump 2-2, and partially transported to the low-boiling point solvent buffer tank 9. The light components entering the separation tower reflux tank 3-2 are partially transported to the top reflux of the DMF separation tower 3 through the DMF separation tower reflux pump 3-3, and partially transported to the low-boiling point solvent buffer tank 9. The output components of the low-boiling point solvent buffer tank 9 enter the low-boiling point solvent refining tower 10 for refining and purification, and the purified low-boiling point solvent flows into the low-boiling point solvent product tank 4.

[0086] Example 6

[0087] This embodiment provides a recovery device for low boiling point solvent and DMF, and its structural schematic diagram is as follows Figure 6 As shown, the difference from Example 5 is that this embodiment is further provided with a refining tower condenser 11, a phase separation tank 12, and a vacuum pump 13.

[0088] On the basis of Example 5, the light component outlet at the top of the low-boiling point solvent refining tower 10 is connected to the inlet of the phase separation tank 12 via the refining tower condenser 11, the phase separation tank 12 has an oil phase outlet and a water phase outlet, the oil phase outlet of the phase separation tank 12 is connected to the top inlet of the low-boiling point solvent refining tower 10, the heavy component outlet of the low-boiling point solvent refining tower 10 is connected to the inlet of the low-boiling point solvent product tank 4, the low-pressure tower condenser 1-1, the separation tower condenser 3-1, and the refining tower condenser 11 are connected to the vacuum pump 13 through a vacuum pipeline.

[0089] The light components at the top of the low-boiling-point solvent refining tower 10 are condensed by the refining tower condenser 11 and then enter the phase separation tank 12 for phase separation. The oil phase of the separated water phase returns to the low-boiling-point solvent refining tower 10, and the heavy components of the low-boiling-point solvent refining tower 10 flow into the low-boiling-point solvent product tank 4. The vacuum pump 13 provides a negative pressure environment for the recovery device.

[0090] Example 7

[0091] This embodiment provides a recovery device for low boiling point solvent and DMF, and its structural schematic diagram is as follows Figure 7 As shown, the difference from Example 1 is that in this embodiment, a DMF evaporator 14 and an evaporator condenser 15 are arranged at the front end of the DMF product tank 5.

[0092] On the basis of Example 1, the heavy component outlet at the bottom of the DMF separation tower 3 is respectively connected to the feed port of the separation tower reboiler 3-4 and the inlet of the DMF evaporator 14, and the light component outlet of the DMF evaporator 14 is connected to the inlet of the DMF product tank 5 via the evaporator condenser 15.

[0093] The heavy components at the bottom of the DMF separation tower 3 are partially circulated back to the DMF separation tower 3 through the separation tower reboiler 3-4, and partially enter the DMF evaporator 14 for de-weighting. The light components of the DMF evaporator 14 are condensed by the evaporator condenser 15 and enter the DMF product tank 5.

Claims

1. A recovery device for low boiling point solvent and DMF, characterized in that, It includes a low-pressure tower (1), a high-pressure tower (2), a DMF separation tower (3), a low-boiling-point solvent product tank (4) and a DMF product tank (5); The low-pressure tower (1) is provided with a DMF waste liquid inlet, the heavy component outlet at the bottom of the low-pressure tower (1) is connected to the inlet of the high-pressure tower (2), the heavy component outlet at the bottom of the high-pressure tower (2) is connected to the inlet of the DMF separation tower (3), and the heavy component outlet at the bottom of the DMF separation tower (3) is connected to the DMF product tank (5); The light component outlet at the top of the low-pressure tower (1) is connected to the inlet of the low-pressure tower reflux tank (1-2) via the low-pressure tower condenser (1-1), the light component outlet at the top of the high-pressure tower (2) is connected to the heat medium inlet of the low-pressure tower reboiler (1-4), and the heat medium outlet of the low-pressure tower reboiler (1-4) is connected to the inlet of the high-pressure tower reflux tank (2-1); The bottom outlet of the low-pressure tower reflux tank (1-2) is respectively connected to the top reflux liquid inlet of the low-pressure tower (1) and the inlet of the low-boiling-point solvent product tank (4) via the low-pressure tower reflux pump (1-3); the bottom outlet of the high-pressure tower reflux tank (2-1) is respectively connected to the top reflux liquid inlet of the high-pressure tower (2) and the inlet of the low-boiling-point solvent product tank (4) via the high-pressure tower reflux pump (2-2); and the bottom outlet of the separation tower reflux tank (3-2) is respectively connected to the top reflux liquid inlet of the DMF separation tower (3) and the inlet of the low-boiling-point solvent product tank (4) via the DMF separation tower reflux pump (3-3).

2. The recovery device of the low boiling point solvent and DMF according to claim 1, characterized in that, A low-pressure tower preheater (6) is provided before the DMF waste liquid inlet of the low-pressure tower (1); The heavy component outlet at the bottom of the DMF separation tower (3) is respectively connected to the feed inlet of the DMF separation tower reboiler (3-4) and the heat medium inlet of the low-pressure tower preheater (6), and the heat medium outlet of the low-pressure tower preheater (6) is connected to the inlet of the DMF product tank (5).

3. The recovery device of the low boiling point solvent and DMF according to claim 1, characterized in that, Also included is a high pressure column condenser (2-4); The light component outlet at the top of the high-pressure tower (2) is directly connected to the inlet of the high-pressure tower reflux tank (2-1) and the low-pressure tower reboiler (1-4) respectively; The heat medium outlet of the low-pressure tower reboiler (1-4) is connected to the inlet of the high-pressure tower reflux tank (2-1), and the top outlet of the high-pressure tower reflux tank (2-1) is connected to the inlet of the high-pressure tower condenser (2-4); The liquid phase outlet of the high-pressure tower condenser (2-4) is connected to the inlet of the high-pressure tower reflux tank (2-1).

4. The recovery device of the low boiling point solvent and DMF according to claim 1, characterized in that, A separation tower buffer tank (7) is also provided; The heavy component outlet at the bottom of the high-pressure tower (2) is connected to the inlet of the separation tower buffer tank (7), and the outlet of the separation tower buffer tank (7) is connected to the inlet of the DMF separation tower (3) via a transfer pump (8).

5. The recovery device of the low boiling point solvent and DMF according to claim 4, characterized in that, The heat medium outlet of the low-pressure tower reboiler (1-4) is connected to the inlet of the high-pressure tower condenser (2-4), and the outlet of the high-pressure tower condenser (2-4) is connected to the inlet of the high-pressure tower reflux tank (2-1).

6. The recovery device of the low boiling point solvent and DMF according to claim 1, characterized in that, A low boiling point solvent buffer tank (9) and a low boiling point solvent refining tower (10) are provided before the inlet of the low boiling point solvent product tank (4); The inlet of the low-boiling-point solvent buffer tank (9) is respectively connected to the bottom outlet of the low-pressure tower reflux tank (1-2), the bottom outlet of the high-pressure tower reflux tank (2-1) and the bottom outlet of the separation tower reflux tank (3-2); the outlet of the low-boiling-point solvent buffer tank (9) is connected to the inlet of the low-boiling-point solvent refining tower (10); and the bottom outlet of the low-boiling-point solvent refining tower (10) is connected to the inlet of the low-boiling-point solvent product tank (4).

7. The recovery device of the low boiling point solvent and DMF according to claim 6, characterized in that, A phase separation tank (12) is also provided, wherein the phase separation tank (12) has an oil phase outlet and a water phase outlet; The light component outlet at the top of the low-boiling-point solvent refining tower (10) is connected to the inlet of the phase separation tank (12) via the refining tower condenser (11), and the oil phase outlet of the phase separation tank (12) is connected to the top inlet of the low-boiling-point solvent refining tower (10).

8. The recovery device of the low boiling point solvent and DMF according to claim 1, characterized in that, A DMF evaporator (14) is also provided; The heavy component outlet at the bottom of the DMF separation tower (3) is respectively connected to the feed port of the separation tower reboiler (3-4) and the inlet of the DMF evaporator (14), and the light component outlet of the DMF evaporator (14) is connected to the inlet of the DMF product tank (5) via the evaporator condenser (15).

9. The recovery device for the low boiling point solvent and DMF according to any one of claims 1 to 8, characterized in that: The low-pressure tower reboiler (1-4) is selected from a falling film reboiler, a thermosyphon reboiler, a forced circulation reboiler, and a kettle reboiler.

10. The recovery device for the low boiling point solvent and DMF according to any one of claims 1 to 8, characterized in that: It also includes a vacuum pump (13), and the low-pressure tower condenser (1-1), the separation tower condenser (3-1), and the refining tower condenser (11) are all connected to the vacuum pump (13) through a vacuum pipeline.

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