Separation device for acetonitrile mixed liquid

Abstract

The utility model provides a separation device for acetonitrile mixed liquor. The separation device comprises an extraction tower, a high-pressure tower, a low-pressure tower, an extraction tower condenser, an extraction tower reboiler, a high-pressure tower condenser, a high-pressure tower reboiler, a low-pressure tower condenser, a low-pressure tower reboiler, an acetonitrile recovery tank and an azeotropic solvent recovery tank, wherein a tower top light component outlet of the extraction tower is respectively communicated with a tower top reflux liquid inlet of the extraction tower and a feeding hole of the high-pressure tower through an extraction tower condenser, and a tower top light component outlet of the high-pressure tower is respectively communicated with a tower top reflux liquid inlet of the high-pressure tower and a feeding hole of the low-pressure tower through a high-pressure tower condenser; and a tower top light component outlet of the low-pressure tower is respectively communicated with a tower top reflux liquid inlet of the low-pressure tower and a feeding hole of the high-pressure tower through a low-pressure tower condenser. Compared with the prior art, the separation device for the acetonitrile-containing mixed liquid provided by the utility model has the advantages of simple process, thorough separation, high product purity, energy conservation and consumption reduction.

Description

Technical Field

[0001] The utility model relates to the technical field of separation and purification in the chemical industry, and more specifically to a separation device for an acetonitrile mixed liquid. Background Art

[0002] Acetonitrile has excellent solvent properties and can dissolve a variety of organic, inorganic and gaseous substances. Acetonitrile is an irreplaceable excellent solvent in many reactions. However, the use of acetonitrile as a chemical solvent not only requires high-purity acetonitrile, but also requires other solvents to be added to the system after the reaction, resulting in a large amount of azeotropic solvents containing water and acetonitrile and a mixed solution of acetonitrile. Due to the good solubility of acetonitrile, it is quite difficult to separate acetonitrile from the acetonitrile mixed solution, and the requirements for the separation device are also relatively high.

[0003] A Chinese patent with publication number CN103214345A discloses a process for separating a ternary mixture of methanol, acetonitrile and benzene. The process adopts a five-tower pressure swing distillation device including a primary separation tower, a first low-pressure methanol tower, a second low-pressure methanol tower, a benzene tower and an acetonitrile tower. The pressure reduction and pressure distillation are combined on the basis of atmospheric distillation. Although the separation of the ternary mixture is achieved, the process flow is relatively complicated, heat recovery is not achieved, and energy consumption is increased. Utility Model Content

[0004] In view of this, the purpose of the utility model is to provide a separation device for a mixed liquid containing acetonitrile, which has the advantages of simple process, thorough separation, high product purity, energy saving and consumption reduction.

[0005] The utility model provides a separation device for acetonitrile mixed liquid, comprising:

[0006] Extraction tower, high-pressure tower, low-pressure tower, extraction tower condenser, extraction tower reboiler, high-pressure tower condenser, high-pressure tower reboiler, low-pressure tower condenser, low-pressure tower reboiler, acetonitrile recovery tank, azeotropic solvent recovery tank;

[0007] The light component outlet at the top of the extraction tower is connected to the top reflux liquid inlet of the extraction tower and the feed inlet of the high-pressure tower through the extraction tower condenser, the light component outlet at the top of the high-pressure tower is connected to the top reflux liquid inlet of the high-pressure tower and the feed inlet of the low-pressure tower through the high-pressure tower condenser, and the light component outlet at the top of the low-pressure tower is connected to the top reflux liquid inlet of the low-pressure tower and the feed inlet of the high-pressure tower through the low-pressure tower condenser;

[0008] The heavy component outlet at the bottom of the high-pressure tower is connected to the inlet of the acetonitrile recovery tank, and the heavy component outlet at the bottom of the low-pressure tower is connected to the inlet of the azeotropic solvent recovery tank.

[0009] or,

[0010] The heavy component outlet at the bottom of the low-pressure tower is communicated with the inlet of the acetonitrile recovery tank, and the heavy component outlet at the bottom of the high-pressure tower is communicated with the inlet of the azeotropic solvent recovery tank.

[0011] The separation device provided by the utility model is used for separating and recovering the azeotropic solvent and acetonitrile in the acetonitrile mixed liquid, and the main components of the acetonitrile mixed liquid are acetonitrile, water and the solvent azeotropic with acetonitrile, such as methanol, ethanol, ethyl acetate, methyl tert-butyl ether, isopropanol, etc. The acetonitrile mixed liquid enters the extraction tower for extraction and distillation, and the light component containing acetonitrile and the azeotropic solvent is obtained after the water in the mixed liquid is extracted by the extractant, and the light component is condensed by the extraction tower condenser, and part of the condensate is circulated to the top of the extraction tower, and part of the condensate is transported to the high-pressure tower for high-pressure distillation, and the heavy component at the bottom of the high-pressure tower flows into the acetonitrile recovery tank or the azeotropic solvent recovery tank, and the light component at the top of the high-pressure tower is condensed by the high-pressure tower condenser, and part of the condensate is circulated to the top of the high-pressure tower, and part of the condensate is transported to the low-pressure tower for distillation, and the heavy component at the bottom of the low-pressure tower flows into the azeotropic solvent recovery tank or the acetonitrile recovery tank, and part of the condensate of the light component at the top of the low-pressure tower after condensation by the low-pressure tower condenser is circulated to the top of the low-pressure tower, and part of the condensate is transported to the high-pressure tower. When the boiling point of the azeotropic solvent is higher than that of acetonitrile, the heavy components at the bottom of the high-pressure tower flow into the azeotropic solvent recovery tank, and the heavy components at the bottom of the low-pressure tower flow into the acetonitrile recovery tank; when the boiling point of the azeotropic solvent is lower than that of acetonitrile, the heavy components at the bottom of the high-pressure tower flow into the acetonitrile recovery tank, and the heavy components at the bottom of the low-pressure tower flow into the azeotropic solvent recovery tank. In the utility model, the extractant is preferably one of ethylene glycol, DMF, and NMP.

[0012] In order to improve the distillation efficiency, as a preferred solution, in the device provided by the utility model, the separation device is further provided with:

[0013] Crude steam tower, crude steam tower condenser, crude steam tower reboiler;

[0014] The light component outlet at the top of the crude distillation tower is connected to the reflux inlet of the crude distillation tower and the material inlet of the extraction tower through the crude distillation tower condenser. The acetonitrile mixed liquid enters the crude distillation tower for preliminary concentration, and most of the water phase in the mixed liquid is separated. After the light component at the top of the crude distillation tower is condensed by the crude distillation tower condenser, part of the condensate is circulated to the crude distillation tower reflux, and part of the condensate is transported to the extraction tower for extraction and distillation.

[0015] In order to realize the recycling of the extractant and improve the selectivity of the extractant, as a preferred solution, in the device provided by the utility model, the separation device is further provided with:

[0016] Extractant regeneration tower, regeneration tower condenser, regeneration tower reboiler;

[0017] The heavy component outlet at the bottom of the extraction tower is connected to the material inlet of the extractant regeneration tower, and the extractant outlet at the bottom of the extractant regeneration tower is connected to the extractant inlet in the middle of the extraction tower. The heavy component at the bottom of the tower obtained by distillation in the extraction tower enters the extractant regeneration tower to remove moisture from the extractant, and returns to the extraction tower from the bottom of the extractant regeneration tower.

[0018] In one embodiment of the utility model, in the device provided by the utility model, the extractant inlet in the middle of the extraction tower is at the upper end of the material inlet of the extraction tower. The extractant after dehydration in the extractant regeneration tower enters the extraction tower from the extractant inlet located at the upper end of the material inlet of the extraction tower, thereby improving the gas-liquid mass transfer efficiency.

[0019] In one embodiment of the utility model, in the device provided by the utility model, the extractant outlet of the extractant regeneration tower is connected to the heat medium inlet of the extraction tower reboiler, and the heat medium outlet of the extraction tower reboiler is connected to the extractant inlet of the extraction tower. The extractant after dehydration in the extractant regeneration tower enters the extraction tower reboiler, and as the heat medium of the extraction tower, it exchanges heat with the mixed liquid of acetonitrile and the azeotropic solvent and then enters the extraction tower.

[0020] In one embodiment of the utility model, in the device provided by the utility model, the separation device is further provided with:

[0021] Crude steam tower preheater;

[0022] The heavy component outlet at the bottom of the crude distillation tower is connected to the heat medium inlet of the crude distillation tower preheater, and the material outlet of the crude distillation tower preheater is connected to the feed inlet of the crude distillation tower. The heavy component at the bottom of the crude distillation tower separated by rectification is used as the heat medium of the crude distillation tower preheater to preheat the acetonitrile mixed liquid. The preheated acetonitrile mixed liquid enters the crude distillation tower for preliminary concentration, which fully utilizes the heat of the heavy component at the bottom of the crude distillation tower and reduces energy consumption.

[0023] In one embodiment of the utility model, in the device provided by the utility model, the separation device is further provided with:

[0024] High pressure tower preheater;

[0025] The heavy component outlet at the bottom of the high-pressure tower is connected to the heat medium inlet of the high-pressure tower preheater, the heat medium outlet of the high-pressure tower preheater is connected to the inlet of the acetonitrile recovery tank or the azeotropic solvent recovery tank, the outlet of the extraction tower condenser and the outlet of the low-pressure tower condenser are respectively connected to the material inlet of the high-pressure tower preheater, and the material outlet of the high-pressure tower preheater is connected to the feed port of the high-pressure tower. The condensate from the extraction tower condenser and the condensate from the low-pressure tower condenser are preheated by the high-pressure tower preheater and then enter the high-pressure tower for high-pressure distillation. The heavy component at the bottom of the high-pressure tower serves as the heat medium of the high-pressure tower preheater, and then enters the acetonitrile recovery tank or the azeotropic solvent recovery tank after heat exchange with the condensate from the extraction tower condenser and the condensate from the low-pressure tower condenser. The heat of the heavy component at the bottom of the high-pressure tower is used to reduce the temperature difference between the material to be separated and the material in the high-pressure tower, thereby reducing energy consumption.

[0026] In one embodiment of the utility model, in the device provided by the utility model, the separation device is further provided with:

[0027] Low pressure tower preheater;

[0028] The bottom heavy component outlet of the low-pressure tower is connected to the heat medium inlet of the low-pressure tower preheater, the heat medium outlet of the low-pressure tower preheater is connected to the inlet of the azeotropic solvent recovery tank or the acetonitrile recovery tank, the outlet of the high-pressure tower condenser is connected to the material inlet of the low-pressure tower preheater, and the material outlet of the low-pressure tower preheater is connected to the feed inlet of the low-pressure tower. The condensate from the high-pressure tower condenser is preheated by the low-pressure tower preheater and enters the low-pressure tower for distillation. The bottom heavy component of the low-pressure tower is used as the heat medium of the low-pressure tower preheater, and enters the azeotropic solvent recovery tank or the acetonitrile recovery tank after heat exchange with part of the condensate flowing out of the high-pressure tower condenser. The heat of the bottom heavy component of the low-pressure tower is used to reduce the temperature difference between the material to be separated and the material in the low-pressure tower, thereby reducing energy consumption.

[0029] In one embodiment of the utility model, in the device provided by the utility model, the separation device is further provided with:

[0030] Booster pump;

[0031] The outlet of the extraction tower condenser and the outlet of the low-pressure tower condenser are respectively connected to the inlet of the booster pump, and the outlet of the booster pump is connected to the feed port of the high-pressure tower. The condensate from the extraction tower condenser and the condensate from the low-pressure tower condenser are pressurized by the booster pump and enter the high-pressure tower, reducing the pressure difference with the material in the high-pressure tower, making the separation process more stable.

[0032] In the present invention, the reboiler is preferably selected from one of a falling film reboiler, a thermosyphon reboiler, a forced circulation reboiler or a kettle reboiler.

[0033] 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.

[0034] In the utility model, various components of the production device, such as the extraction tower, the high-pressure tower, the low-pressure tower, the condenser, the reboiler, the buffer tank, the preheater, 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.

[0035] The utility model provides a separation device for acetonitrile mixed liquid, comprising: an extraction tower, a high-pressure tower, a low-pressure tower, an extraction tower condenser, an extraction tower reboiler, a high-pressure tower condenser, a high-pressure tower reboiler, a low-pressure tower condenser, a low-pressure tower reboiler, an acetonitrile recovery tank, and an azeotropic solvent recovery tank; wherein the light component outlet at the top of the extraction tower is respectively connected to the top reflux liquid inlet of the extraction tower and the feed inlet of the high-pressure tower through the extraction tower condenser, and the light component outlet at the top of the high-pressure tower is respectively connected to the top reflux liquid inlet of the high-pressure tower through the high-pressure tower condenser The liquid inlet of the low-pressure tower is connected to the feed port of the low-pressure tower, and the light component outlet of the top of the low-pressure tower is respectively connected to the reflux liquid inlet of the top of the low-pressure tower and the feed port of the high-pressure tower through the low-pressure tower condenser; the heavy component outlet at the bottom of the high-pressure tower is connected to the inlet of the acetonitrile recovery tank, and the heavy component outlet at the bottom of the low-pressure tower is connected to the inlet of the azeotropic solvent recovery tank, or the heavy component outlet at the bottom of the low-pressure tower is connected to the inlet of the acetonitrile recovery tank, and the heavy component outlet at the bottom of the high-pressure tower is connected to the inlet of the azeotropic solvent recovery tank. Compared with the prior art, the separation device for the mixed liquid containing acetonitrile provided by the utility model has the advantages of simple process, thorough separation, high product purity, energy saving and consumption reduction.

[0036] In summary, compared with the prior art, the separation device for acetonitrile mixed liquid provided by the utility model has the following beneficial effects:

[0037] The separation device provided by the utility model adopts an extraction tower, a high-pressure tower and a low-pressure tower connected in series in sequence, and separates and recovers acetonitrile and azeotropic solvent from an acetonitrile mixed liquid containing water and azeotropic solvent through dehydration and pressure-variable distillation, thereby solving the problem of separation difficulty caused by the existence of multiple groups of azeotropes. Part of the condensate of the light components separated by each stage of the distillation tower is condensed by a condenser and circulated back to the top of the tower, and part of the condensate is transported to the next stage of the tower for distillation, so as to obtain acetonitrile and azeotropic solvent with a purity of not less than 99.5%, and the separation is thorough, and the equipment investment cost is low. At the same time, the separation device provided by the utility model uses the heavy component at the bottom of the distillation tower as a heat medium for preheating the material to be separated through a heat integration method, thereby avoiding the problem that the heat energy of the heavy component of the distillation tower cannot be utilized and a large amount of cooling water needs to be consumed for cooling, and the energy-saving effect is remarkable. BRIEF DESCRIPTION OF THE DRAWINGS

[0038] Figure 1 A schematic diagram of the structure of the separation device for the acetonitrile mixed solution provided in Example 1 of the utility model;

[0039] Figure 2 A schematic diagram of the structure of a separation device for an acetonitrile mixed solution provided in Example 2 of the utility model;

[0040] Figure 3 A schematic diagram of the structure of a separation device for an acetonitrile mixed solution provided in Example 3 of the present utility model;

[0041] Figure 4 A schematic diagram of the structure of a separation device for an acetonitrile mixed solution provided in Example 4 of the utility model;

[0042] Figure 5 A schematic diagram of the structure of a separation device for an acetonitrile mixed solution provided in Example 5 of the present utility model;

[0043] Among them, 1 extraction tower, 1-1 extraction tower condenser, 1-2 extraction tower reboiler, 2 high-pressure tower, 2-1 high-pressure tower condenser, 2-2 high-pressure tower reboiler, 2-3 high-pressure tower preheater, 3 low-pressure tower, 3-1 low-pressure tower condenser, 3-2 low-pressure tower reboiler, 3-3 low-pressure tower preheater, 4 acetonitrile recovery tank, 5 azeotropic solvent recovery tank, 6 crude distillation tower, 6-1 crude distillation tower condenser, 6-2 crude distillation tower reboiler, 6-3 crude distillation tower preheater, 7 extractant regeneration tower, 7-1 regeneration tower condenser, 7-2 regeneration tower reboiler, 8 booster pump. DETAILED DESCRIPTION

[0044] The following will be combined with the embodiments of the utility model to clearly and completely describe the technical solution 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.

[0045] Example 1

[0046] See also Figure 1 , Figure 1 A schematic structural diagram of an acetonitrile mixed liquid separation device provided in Example 1 of the utility model; comprising an extraction tower 1, an extraction tower condenser 1-1, a high-pressure tower 2, a high-pressure tower condenser 2-1, a low-pressure tower 3, a low-pressure tower condenser 3-1, an acetonitrile recovery tank 4, and an azeotropic solvent recovery tank 5 connected in series in sequence.

[0047] Among them, the light component outlet at the top of the extraction tower 1 is connected to the top reflux liquid inlet of the extraction tower 1 and the feed port of the high-pressure tower 2 through the extraction tower condenser 1-1, the heavy component outlet at the bottom of the high-pressure tower 2 is connected to the inlet of the acetonitrile recovery tank 4, the light component outlet at the top of the high-pressure tower 2 is connected to the top reflux liquid inlet of the high-pressure tower 2 and the feed port of the low-pressure tower 3 through the high-pressure tower condenser 2-1, the heavy component outlet at the bottom of the low-pressure tower 3 is connected to the inlet of the azeotropic solvent recovery tank 5, and the light component outlet at the top of the low-pressure tower 3 is connected to the top reflux liquid inlet of the low-pressure tower 3 and the feed port of the high-pressure tower 2 through the low-pressure tower condenser 3-1.

[0048] The specific working process is as follows:

[0049] The acetonitrile mixed liquid and the extractant enter the extraction tower 1 for extractive distillation, and the light component containing acetonitrile and the azeotropic solvent is obtained after the water in the mixed liquid is extracted by the extractant. After the light component is condensed by the extraction tower condenser 1-1, part of the condensate is circulated to the top of the extraction tower 1, and part of the condensate is transported to the high-pressure tower 2 for high-pressure distillation. The heavy component at the bottom of the high-pressure tower 2 flows into the acetonitrile recovery tank 4, and the light component at the top of the high-pressure tower 2 is condensed by the high-pressure tower condenser 2-1, and part of the condensate is circulated to the top of the high-pressure tower 2, and part of the condensate is transported to the low-pressure tower 3 for distillation. The heavy component at the bottom of the low-pressure tower 3 flows into the azeotropic solvent recovery tank 5, and the light component at the top of the low-pressure tower 3 is condensed by the low-pressure tower condenser 3-1, and part of the condensate is circulated to the top of the low-pressure tower 3, and part of the condensate is transported to the high-pressure tower 2 for high-pressure distillation.

[0050] Example 2

[0051] See also Figure 2 , Figure 2A schematic structural diagram of an acetonitrile mixed liquid separation device provided in Example 2 of the present utility model; the difference from Example 1 is that this embodiment is further provided with a crude distillation tower 6, a crude distillation tower condenser 6-1, and a crude distillation tower reboiler 6-2.

[0052] On the basis of Example 1, the light component outlet at the top of the crude distillation tower 6 is connected to the reflux liquid inlet of the crude distillation tower 6 and the material inlet of the extraction tower 1 respectively through the crude distillation tower condenser 6-1, the heavy component outlet at the bottom of the crude distillation tower 6 is connected to the inlet of the crude distillation tower reboiler 6-2, and the outlet of the crude distillation tower reboiler 6-2 is connected to the bottom inlet of the crude distillation tower 6.

[0053] The acetonitrile mixture first enters the crude distillation tower 6 for preliminary concentration to separate most of the water phase in the mixture. The light components at the top of the crude distillation tower 6 are condensed by the crude distillation tower condenser 6-1, and part of the condensate is circulated to the crude distillation tower 6 for reflux, and part of the condensate is transported to the extraction tower 1 for extraction distillation.

[0054] Example 3

[0055] See also Figure 3 , Figure 3 The schematic diagram of the structure of the separation device of the acetonitrile mixed liquid provided in Example 3 of the utility model comprises an extraction tower 1, an extraction tower condenser 1-1, an extraction tower reboiler 1-2, a high-pressure tower 2, a high-pressure tower condenser 2-1, a high-pressure tower reboiler 2-2, a low-pressure tower 3, a low-pressure tower condenser 3-1, a low-pressure tower reboiler 3-2, an acetonitrile recovery tank 4, an azeotropic solvent recovery tank 5, a crude distillation tower 6, a crude distillation tower condenser 6-1, a crude distillation tower reboiler 6-2, an extractant regeneration tower 7, a regeneration tower condenser 7-1, and a regeneration tower reboiler 7-2. The reboiler is selected from a falling film reboiler, a thermosyphon reboiler, a forced circulation reboiler, and a kettle reboiler.

[0056] Among them, the heavy component outlet at the bottom of the crude distillation tower 6 is connected to the inlet of the crude distillation tower reboiler 6-2, the outlet of the crude distillation tower reboiler 6-2 is connected to the bottom inlet of the crude distillation tower 6, the light component outlet at the top of the crude distillation tower 6 is respectively connected to the reflux liquid inlet of the crude distillation tower 6 and the material inlet of the extraction tower 1 through the crude distillation tower condenser 6-1, the heavy component outlet at the bottom of the extraction tower 1 is respectively connected to the inlet of the extraction tower reboiler 1-2 and the material inlet of the extractant regeneration tower 7, the outlet of the extraction tower reboiler 1-2 is connected to the bottom inlet of the extraction tower 1, the light component outlet at the top of the extractant regeneration tower 7 is connected to the inlet of the regeneration tower condenser 7-1, the condensate outlet of the regeneration tower condenser 7-1 is connected to the condensate inlet of the extractant regeneration tower 7, the extractant outlet at the bottom of the extractant regeneration tower 7 is respectively connected to the inlet of the regeneration tower reboiler 7-2 and the extractant inlet in the middle of the extraction tower 1, and the extractant inlet in the middle of the extraction tower 1 is at the material inlet of the extraction tower 1. At the upper end, the outlet of the regeneration tower reboiler 7-2 is connected to the bottom inlet of the extractant regeneration tower 7, the light component outlet of the top of the extraction tower 1 is respectively connected to the top reflux liquid inlet of the extraction tower 1 and the feed inlet of the high-pressure tower 2 through the extraction tower condenser 1-1, the heavy component outlet at the bottom of the high-pressure tower 2 is respectively connected to the inlet of the high-pressure tower reboiler 2-2 and the inlet of the azeotropic solvent recovery tank 5, the outlet of the high-pressure tower reboiler 2-2 is connected to the bottom inlet of the high-pressure tower 2, and the top of the high-pressure tower 2 is connected to the bottom inlet of the high-pressure tower 2. The light component outlet is connected to the top reflux liquid inlet of high-pressure tower 2 and the feed port of low-pressure tower 3 respectively through the high-pressure tower condenser 2-1, the heavy component outlet at the bottom of low-pressure tower 3 is connected to the inlet of low-pressure tower reboiler 3-2 and the inlet of acetonitrile recovery tank 4 respectively, the outlet of low-pressure tower reboiler 3-2 is connected to the bottom inlet of low-pressure tower 3, and the light component outlet at the top of low-pressure tower 3 is connected to the top reflux liquid inlet of low-pressure tower 3 and the feed port of high-pressure tower 2 respectively through the low-pressure tower condenser 3-1.

[0057] The specific working process is as follows:

[0058] The acetonitrile mixed liquid enters the crude distillation tower 6 for preliminary concentration. The heavy components at the bottom of the crude distillation tower 6 are heated by the crude distillation tower reboiler 6-2 and rise along the tower body, and continuously transfer mass and heat with the upper descending liquid. The light components at the top of the crude distillation tower 6 are condensed by the crude distillation tower condenser 6-1, and part of the condensate is circulated to the crude distillation tower 6 for reflux, and part of the condensate is transported to the extraction tower 1 for extraction and distillation. Some of the heavy components of the extraction tower 1 are heated by the extraction tower reboiler 1-2 and returned to the extraction tower 1. Some of the heavy components enter the extractant regeneration tower 7 for distillation and water removal. After the light components separated by the extractant regeneration tower 7 are condensed by the regeneration tower condenser 7-1, part of the condensate returns to the extractant regeneration tower 7, and part of the condensate is discharged. Some of the heavy components of the extractant regeneration tower 7 are heated by the reboiler 7-2 and returned to the extractant regeneration tower 7. Some of the heavy components enter the extraction tower 1 for extraction and distillation. After the light components separated by the extraction tower 1 are condensed by the extraction tower condenser 1-1, part of the condensate is circulated to the top of the extraction tower 1, and part of the condensate is transported to the high-pressure tower 2 for high-pressure distillation. Part of the heavy components at the bottom of the high-pressure tower 2 are heated by the high-pressure tower reboiler 2-2 and returned to the high-pressure tower 2, and part of the heavy components at the bottom of the tower flow into the azeotropic solvent recovery tank 5. After the light components at the top of the high-pressure tower 2 are condensed by the high-pressure tower condenser 2-1, part of the condensate is circulated to the top of the high-pressure tower 2, and part of the condensate is transported to the low-pressure tower 3 for distillation. Part of the heavy components at the bottom of the low-pressure tower 3 are heated by the low-pressure tower reboiler 3-2 and returned to the low-pressure tower 3, and part of the heavy components at the bottom of the tower flow into the acetonitrile recovery tank 4. After the light components at the top of the low-pressure tower 3 are condensed by the low-pressure tower condenser 3-1, part of the condensate is circulated to the top of the low-pressure tower 3, and part of the condensate is transported to the high-pressure tower 2 for high-pressure distillation.

[0059] Example 4

[0060] See also Figure 4 , Figure 4 This is a schematic structural diagram of the acetonitrile mixed liquid separation device provided in Example 4 of the utility model; the difference from Example 3 is that this embodiment is also provided with a booster pump 8.

[0061] On the basis of Example 3, the extractant outlet of the extractant regeneration tower 7 is connected to the heat medium inlet of the extraction tower reboiler 1-2, the heat medium outlet of the extraction tower reboiler 1-2 is connected to the extractant inlet of the extraction tower 1, the outlet of the extraction tower condenser 1-1 and the outlet of the low-pressure tower condenser 3-1 are respectively connected to the inlet of the booster pump 8, and the outlet of the booster pump 8 is connected to the feed port of the high-pressure tower 2.

[0062] The extractant after dehydration in the extractant regeneration tower 7 flows into the extraction tower reboiler 1-2, and serves as the heat medium of the extraction tower 1 to heat the acetonitrile mixed liquid. After heat exchange in the extraction tower reboiler 1-2, it flows into the extraction tower 1. The condensate from the extraction tower condenser 1-1 and the condensate from the low-pressure tower condenser 3-1 are pressurized by the booster pump 8 and then enter the high-pressure tower 2 for distillation.

[0063] Example 5

[0064] See also Figure 5 , Figure 5 A schematic structural diagram of an acetonitrile mixed liquid separation device provided in Example 5 of the utility model; the difference from Example 3 is that this embodiment is further provided with a crude distillation tower preheater 6-3, a high-pressure tower preheater 2-3, and a low-pressure tower preheater 3-3.

[0065] On the basis of Example 3, the material outlet of the crude steam tower preheater 6-3 is connected to the feed inlet of the crude steam tower 6, and the heavy component outlet at the bottom of the crude steam tower 6 is connected to the heat medium inlet of the crude steam tower preheater 6-3.

[0066] The outlet of the extraction tower condenser 1-1 is respectively connected to the top reflux liquid inlet of the extraction tower 1 and the material inlet of the high-pressure tower preheater 2-3, the material outlet of the high-pressure tower preheater 2-3 is connected to the feed inlet of the high-pressure tower 2, part of the bottom heavy component outlet of the high-pressure tower 2 is connected to the heat medium inlet of the high-pressure tower preheater 2-3, and the heat medium outlet of the high-pressure tower preheater 2-3 is connected to the inlet of the acetonitrile recovery tank 4.

[0067] The outlet of the high-pressure tower condenser 2-1 is respectively connected to the top reflux liquid inlet of the high-pressure tower 2 and the material inlet of the low-pressure tower preheater 3-3, the material outlet of the low-pressure tower preheater 3-3 is connected to the feed inlet of the low-pressure tower 3, part of the bottom heavy component outlet of the low-pressure tower 3 is connected to the heat medium inlet of the low-pressure tower preheater 3-3, and the heat medium outlet of the low-pressure tower preheater 3-3 is connected to the inlet of the azeotropic solvent recovery tank 5.

[0068] Part of the heavy components at the bottom of the crude distillation tower 6 that have been rectified and separated are used as the heat medium of the crude distillation tower preheater 6-3 to preheat the acetonitrile mixed liquid. The preheated acetonitrile mixed liquid enters the crude distillation tower 6 for preliminary concentration. The condensate from the extraction tower condenser 1-1 and the condensate from the low-pressure tower condenser 3-1 are preheated by the high-pressure tower preheater 2-3 and enter the high-pressure tower 2 for high-pressure distillation. The heavy components at the bottom of the high-pressure tower 2 are used as the heat medium of the high-pressure tower preheater 2-3 and enter the acetonitrile recovery tank 4 after heat exchange with the condensate from the extraction tower condenser 1-1 and the condensate from the low-pressure tower condenser 3-1. The condensate from the high-pressure tower condenser 2-1 is preheated by the low-pressure tower preheater 3-3 and enters the low-pressure tower 3 for distillation. The heavy components at the bottom of the low-pressure tower 3 are used as the heat medium of the low-pressure tower preheater 3-3 and enter the azeotropic solvent recovery tank 5 after heat exchange with part of the condensate flowing out of the high-pressure tower condenser 2-1.

[0069] The above description of the disclosed embodiments enables those skilled in the art to implement or use the present invention. Various modifications to these embodiments will be apparent to those skilled in the art, and the general principles defined herein may be implemented in other embodiments without departing from the spirit or scope of the present invention. Therefore, the present invention will not be limited to the embodiments shown herein, but will conform to the widest scope consistent with the principles and novel features disclosed herein.

Claims

1. A separation device for acetonitrile mixed solution, characterized in that, include: Extraction tower (1), high-pressure tower (2), low-pressure tower (3), extraction tower condenser (1-1), extraction tower reboiler (1-2), high-pressure tower condenser (2-1), high-pressure tower reboiler (2-2), low-pressure tower condenser (3-1), low-pressure tower reboiler (3-2), acetonitrile recovery tank (4), azeotropic solvent recovery tank (5); wherein the light component outlet at the top of the extraction tower (1) is respectively connected to the top reflux liquid inlet of the extraction tower (1) and the feed inlet of the high-pressure tower (2) via the extraction tower condenser (1-1); the light component outlet at the top of the high-pressure tower (2) is respectively connected to the top reflux liquid inlet of the high-pressure tower (2) and the feed inlet of the low-pressure tower (3) via the high-pressure tower condenser (2-1); and the light component outlet at the top of the low-pressure tower (3) is respectively connected to the top reflux liquid inlet of the low-pressure tower (3) and the feed inlet of the high-pressure tower (2) via the low-pressure tower condenser (3-1); The heavy component outlet at the bottom of the high-pressure tower (2) is connected to the inlet of the acetonitrile recovery tank (4), and the heavy component outlet at the bottom of the low-pressure tower (3) is connected to the inlet of the azeotropic solvent recovery tank (5). or, The heavy component outlet at the bottom of the low-pressure tower (3) is connected to the inlet of the acetonitrile recovery tank (4), and the heavy component outlet at the bottom of the high-pressure tower (2) is connected to the inlet of the azeotropic solvent recovery tank (5).

2. The separation device for the acetonitrile mixed solution according to claim 1, characterized in that, Also features: A crude steam tower (6), a crude steam tower condenser (6-1), and a crude steam tower reboiler (6-2); The light component outlet at the top of the crude distillation tower (6) is respectively connected to the reflux liquid inlet of the crude distillation tower (6) and the material inlet of the extraction tower (1) through the crude distillation tower condenser (6-1).

3. The separation device for the acetonitrile mixed solution according to claim 1, characterized in that, Also features: Extractant regeneration tower (7), regeneration tower condenser (7-1), regeneration tower reboiler (7-2); The heavy component outlet at the bottom of the extraction tower (1) is connected to the material inlet of the extractant regeneration tower (7), and the extractant outlet at the bottom of the extractant regeneration tower (7) is connected to the extractant inlet in the middle of the extraction tower (1), and the extractant inlet in the middle of the extraction tower (1) is at the upper end of the material inlet of the extraction tower (1).

4. The separation device for the acetonitrile mixed solution according to claim 3, characterized in that, The extractant outlet of the extractant regeneration tower (7) is connected to the heat medium inlet of the extraction tower reboiler (1-2), and the heat medium outlet of the extraction tower reboiler (1-2) is connected to the extractant inlet of the extraction tower (1).

5. The separation device for the acetonitrile mixed solution according to claim 2, characterized in that, Also features: Crude steam tower preheater (6-3); The heavy component outlet at the bottom of the crude steam tower (6) is connected to the heat medium inlet of the crude steam tower preheater (6-3), and the material outlet of the crude steam tower preheater (6-3) is connected to the feed inlet of the crude steam tower (6).

6. The separation device for the acetonitrile mixed solution according to claim 1, characterized in that, Also features: High pressure tower preheater (2-3); The heavy component outlet at the bottom of the high-pressure tower (2) is connected to the heat medium inlet of the high-pressure tower preheater (2-3), the heat medium outlet of the high-pressure tower preheater (2-3) is connected to the inlet of the acetonitrile recovery tank (4) or the azeotropic solvent recovery tank (5), the outlet of the extraction tower condenser (1-1) and the outlet of the low-pressure tower condenser (3-1) are respectively connected to the material inlet of the high-pressure tower preheater (2-3), and the material outlet of the high-pressure tower preheater (2-3) is connected to the feed inlet of the high-pressure tower (2).

7. The separation device for the acetonitrile mixed solution according to claim 1 or 6, characterized in that: Also features: Low pressure tower preheater (3-3); The heavy component outlet at the bottom of the low-pressure tower (3) is connected to the heat medium inlet of the low-pressure tower preheater (3-3), the heat medium outlet of the low-pressure tower preheater (3-3) is connected to the inlet of the azeotropic solvent recovery tank (5) or the acetonitrile recovery tank (4), the outlet of the high-pressure tower condenser (2-1) is connected to the material inlet of the low-pressure tower preheater (3-3), and the material outlet of the low-pressure tower preheater (3-3) is connected to the feed inlet of the low-pressure tower (3).

8. The separation device for the acetonitrile mixed solution according to claim 1, characterized in that, Also features: Booster pump (8); The outlet of the extraction tower condenser (1-1) and the outlet of the low-pressure tower condenser (3-1) are respectively connected to the inlet of the booster pump (8), and the outlet of the booster pump (8) is connected to the feed port of the high-pressure tower (2).

9. The separation device for the acetonitrile mixed solution according to claim 1, characterized in that, The reboiler is selected from a falling film reboiler, a thermosyphon reboiler, a forced circulation reboiler or a kettle reboiler.

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