Glycolide recovery equipment and recovery method

Abstract

The invention discloses glycolide recovery equipment and a glycolide recovery method. In the glycolide recovery equipment, an evaporator is used for receiving glycolide tailings; the first condenser receives a gas-phase solvent, the bottom of the first condenser is connected with a first condensing unit, and the first condensing unit outputs a condensed liquid-phase solvent; the separator is positioned at the bottom of the evaporator and is directly connected with the bottom of the evaporator through a vertical first material receiving pipe; the separation tower is connected with the separator, the separation tower is connected with the second condenser, the second condenser is connected with a second condensation unit, and the second condensation unit outputs a condensed liquid phase solvent; and the reaction system is positioned at the bottom of the separator and is connected with the bottom of the separator through a vertical second material receiving pipe so as to receive glycolide tailings. According to the glycolide recovery method, glycolide is recovered through glycolide recovery equipment. According to the glycolide recovery equipment and recovery method provided by the invention, the risk of blocking the glycolide tailing conveying pipeline and equipment is reduced, and the sufficient recovery and utilization of the solvent are realized.

Description

Technical Field

[0001] The present application relates to the field of coal chemical technology, and in particular to a glycolide recovery device and a recovery method. Background Art

[0002] Glycolide is a type of cyclic ester compound, which is formed by two molecules of glycolic acid through the elimination of two molecules of water between molecules, and is easily soluble in ethyl acetate. Pure glycolide is a white powdery solid, and its crystals are flaky, with a melting point of 82℃~86℃ and a boiling point of 330℃. Impure glycolide is light yellow. As a polymerization monomer, glycolide can be homopolymerized to obtain polyglycolide, and can also be open-ring copolymerized with other cyclic monomers to obtain random or block copolymers, and it occupies an important position in biodegradable polymer materials.

[0003] From the current process, a part of glycolide tailings will be produced in the process of producing glycolide. The glycolide tailings contain some solvents and oligomers, have a certain viscosity, and glycolide is a heat-sensitive material, so it is particularly important to choose the right production equipment. Since the scraped film evaporator is a device for evaporating glycolide tailings, the rotating scraped film evaporator ensures that the continuous and uniform liquid film produces high-speed turbulence, and prevents the liquid film from coking and scaling on the heating surface, thereby improving the total transfer coefficient. The light component is evaporated to form a rising steam flow and is received, and the heavy component is discharged from the cone at the bottom of the evaporator. The heavy component is a viscous fluid, and its viscosity determines its resistance to flow speed. If the conveying pipeline is too long and the heating is insufficient, it will cause the relevant pipelines and equipment to be blocked, resulting in the inability of the device to operate continuously; and the viscosity of glycolide is large, and the solvent cannot be fully recovered and utilized by evaporating the glycolide tailings through the scraped film evaporator. Summary of the invention

[0004] The purpose of the present application is to provide a glycolide recovery device and a recovery method to reduce the risk of glycolide tail material conveying pipelines and equipment blockages and achieve full recovery and utilization of the solvent.

[0005] The technical solution of the present application provides a glycolide recovery device, including: an evaporator, used to receive glycolide tailings; a first condenser, connected to the evaporator through a first receiving tube to receive a gaseous solvent, the bottom of the first condenser is also connected to a first condensing unit, the first condensing unit is connected to a first output pipe to output the condensed liquid solvent; a separator, located at the bottom of the evaporator and directly connected to the bottom of the evaporator through a vertically extending first receiving tube; a separation tower, connected to the separator through a second receiving tube, the separation tower is connected to a second condenser through a conveying pipe, the second condenser is also connected to a second condensing unit, the second condensing unit is connected to a second output pipe to output the condensed liquid solvent; a reaction system, located at the bottom of the separator and connected to the bottom of the separator through a vertically extending second receiving tube to receive the glycolide tailings.

[0006] Optionally, the glycolide recovery equipment further comprises a first circulation pipe connected between the bottom of the separation tower and the side of the separation tower; a bottom pump and a reboiler are installed on the first circulation pipe.

[0007] Optionally, the glycolide recovery equipment also includes a controller, a second circulation pipe and a liquid level sensor; the second circulation pipe is connected between the first circulation pipe and the side of the separator, the liquid level sensor is installed on the separation tower to monitor the solvent level in the separation tower, and a control valve is provided on the second circulation pipe; the controller is communicatively connected with the liquid level sensor and the control valve, so that when the liquid level sensor detects that the solvent level exceeds a preset threshold, the controller controls the control valve to open.

[0008] Optionally, the first condensing unit comprises a condensing tank, the top of the condensing tank is connected to the bottom of the first condenser via a condensing pipe, and the bottom of the condensing tank is connected to the first output pipe.

[0009] Optionally, the second condensing unit comprises a reflux tank; the bottom of the second condenser is connected to the top of the reflux tank via a reflux pipe, and the bottom of the reflux tank is connected to the second output pipe.

[0010] Optionally, the glycolide recovery equipment further comprises a third circulation pipe, wherein the third circulation pipe is connected between the second output pipe and the top of the separation tower.

[0011] Optionally, the glycolide recovery equipment also includes a vacuum unit, which includes a first vacuum tube connected to the side wall of the first condenser and a second vacuum tube connected to the second condenser; the first vacuum tube is connected to a first vacuum pump, and the second vacuum tube is connected to a second vacuum pump.

[0012] Optionally, a first heating unit for heating glycolide tailings is provided in the evaporator or on the outer wall of the evaporator, and a second heating unit for heating glycolide tailings is provided in the separator or on the outer wall of the separator.

[0013] Optionally, the first heating unit includes a first heat exchange jacket arranged on the outside of the evaporator, and the first heat exchange jacket is connected to a heat exchange liquid inlet pipe and a heat exchange liquid outlet pipe; the second heating unit includes a second heat exchange jacket arranged on the outside of the separator, and the second heat exchange jacket is connected to a heat transfer oil upper oil pipe and a heat transfer oil return pipe.

[0014] The present application also provides a glycolide recovery method, which recovers glycolide through the glycolide recovery equipment described in any of the above items, including: feeding, conveying the glycolide tailings to the evaporator through a feed pipe; primary recovery, evaporating the glycolide tailings in the evaporator, and conveying the generated gaseous solvent from the top of the evaporator to the first condenser through a first receiving pipe, and the glycolide tailings evaporated and condensed in the evaporator enter the separator below through the vertically extending first receiving pipe under the action of gravity and pressure difference; primary recovery and external conveying, the gaseous solvent is condensed into a liquid solvent in the first condenser, the liquid solvent enters the first condensing unit and when the liquid level reaches a preset When the liquid level reaches the preset level, it is output through the first output pipe on the side of the first condensing unit; secondary recovery, the glycolide tailings are evaporated again in the separator, and the gaseous solvent and part of the glycolide tailings enter the separation tower through the second receiving pipe to separate the gaseous solvent and impurities; secondary recovery is transported outward, the separated gaseous solvent enters the second condenser to be cooled into a liquid solvent, the liquid solvent enters the second condensing unit and when the liquid level reaches the preset level, it is output through the second output pipe on the side of the second condensing unit; receiving the material, the reaction system is located at the bottom of the separator and is connected to the bottom of the separator through a vertically extending second receiving pipe to receive the glycolide tailings.

[0015] The above technical solution has the following beneficial effects:

[0016] The glycolide recovery equipment and method provided in the present application arrange the separator at the bottom of the evaporator and directly connect the bottom of the evaporator and the separator through a vertically arranged first receiving pipe, and arrange the reaction system at the bottom of the separator and directly connect the bottom of the separator and the reaction system through a vertically arranged second receiving pipe. Compared with the multi-pipeline and multi-elbow connection in the prior art, the transportation distance of the glycolide tail material is shortened, and the risk of blockage of related pipelines and equipment between the evaporator and the separator, and between the separator and the reaction system is greatly reduced; moreover, through the primary recovery of the evaporator and the first condenser, and the secondary recovery of the separator and the separation tower, the solvent in the glycolide tail material is evaporated and recovered step by step, so as to realize the full recovery and utilization of the solvent, and at the same time avoid the problem of excessive evaporation of the solvent of the glycolide tail material in the evaporator, resulting in excessive viscosity that is not conducive to transportation. BRIEF DESCRIPTION OF THE DRAWINGS

[0017] Figure 1 This is a schematic diagram of the structure of a glycolide recovery device in one embodiment of the present application.

[0018] Figure 2 This is a flow chart of a glycolide recovery device in one embodiment of the present application.

[0019] Reference Numbers

[0020] 1-evaporator, 10-feed pipe;

[0021] 2-first condenser, 20-first receiving tube, 21-first condensing unit, 210-condensing tank, 211-condensing tube, 22-first output tube;

[0022] 3-separator, 30-first receiving pipe;

[0023] 4-separation tower, 40-second receiving pipe, 41-transport pipe, 41-first circulation pipe, 410-bottom pump, 411-reboiler, 42-second circulation pipe, 43-third circulation pipe;

[0024] 5-second condenser, 50-second condensing unit, 500-reflux tank, 501-reflux pipe, 51-second output pipe;

[0025] 6-reaction system, 60-second receiving pipe;

[0026] 70-first vacuum tube, 700-first vacuum pump, 71-second vacuum tube, 710-second vacuum pump;

[0027] 80-heat exchange liquid inlet pipe, 81-heat exchange liquid outlet pipe, 82-heat transfer oil supply pipe, 83-heat transfer oil return pipe, 84-steam liquid inlet pipe, 85-steam liquid outlet pipe, 86-cooling water supply pipe, 87-cooling water return pipe. DETAILED DESCRIPTION

[0028] The specific implementation of the present invention will be further described below in conjunction with the accompanying drawings.

[0029] It is easy to understand that according to the technical solution of the present invention, without changing the essential spirit of the present invention, a variety of structural modes and implementation modes that can be replaced by those skilled in the art can be replaced with each other. Therefore, the following specific implementation modes and drawings are only exemplary descriptions of the technical solution of the present invention, and should not be regarded as the whole of the present invention or as a limitation or restriction to the technical solution of the invention.

[0030] The directional terms such as up, down, left, right, front, back, front, back, top, bottom, etc. mentioned or may be mentioned in this specification are defined relative to the structures shown in the drawings. They are relative concepts and may change accordingly according to different positions and different usage conditions. Therefore, these or other directional terms should not be interpreted as restrictive terms.

[0031] The present application provides a glycolide recovery device, comprising: an evaporator 1, a first condenser 2, a separator 3, a separation tower 4 and a reaction system 6.

[0032] Please refer to Figure 1 , the evaporator 1 is used to receive glycolide tailings. The evaporator 1 may be a scraped film evaporator 1, and a feed pipe 10 is connected to the side wall of the evaporator 1, through which the glycolide tailings are received. The top or upper side wall of the first condenser 2 is connected to the top or upper side of the evaporator 1 through a first receiving pipe 20 to receive the gas phase solvent evaporated from the glycolide tailings in the evaporator 1, and the bottom of the first condenser 2 is also connected to a first condensing unit 21, and the first condensing unit 21 is connected to a first output pipe 22 to output the liquid phase solvent condensed by the first condenser 2.

[0033] like Figure 1 As shown, the separator 3 is located at the bottom of the evaporator 1 and is directly connected to the bottom of the evaporator 1 through a vertically extending first receiving pipe 30; the evaporator 1 is installed on the upper part of the separator 3, and the glycolide tailings concentrated in the evaporator 1 are directly discharged to the separator 3 through the vertical first receiving pipe 30 under the action of gravity, shortening the transportation distance of the glycolide tailings. Compared with the prior art, the risk of blockage of related pipelines and equipment between the evaporator 1 and the separator 3 is greatly reduced. The top or upper side of the separation tower 4 is connected to the top or upper side of the separator 3 through a second receiving pipe 40, and the top of the separation tower 4 is connected to the top of the second condenser 5 through a delivery pipe 41. The bottom or lower side of the second condenser 5 is also connected to a second condensing unit 50, and the second condensing unit 50 is connected to a second output pipe 51 to output the condensed liquid phase solvent.

[0034] The reaction system 6 is located at the bottom of the separator 3 and is connected to the bottom of the separator 3 through a second vertically extending receiving pipe 60 to receive glycolide tailings. After the glycolide tailings are recovered by two solvent evaporations in the evaporator 1 and the separator 3, the remaining glycolide tailings enter the reaction system 6 by gravity for recovery and utilization, thereby meeting the continuous production requirements of the device.

[0035] During the operation of the glycolide recovery equipment in the embodiment of the present application, first, the glycolide tailings enter the evaporator 1 through the feed pipe 10, and under the action of a certain temperature and pressure, part of the solvent is evaporated from the glycolide tailings and transported to the first condenser 2, and the gaseous solvent is condensed into a liquid solvent in the first condenser 2 and then transported to the outside after the buffering effect of the first condensing unit 21; and the glycolide tailings and part of the solvent initially concentrated by the evaporator 1 enter the separator 3 under the action of gravity, and are evaporated again at a certain temperature and pressure in the separator 3, the evaporated solvent and part of the glycolide tailings enter the separation tower 4, and the solvent and impurities (including the glycolide tailings) are separated in the separation tower 4, and the solvent separated by the separation tower 4 is cooled by the second condenser 5, collected in the reflux tank 500, and transported to the outside through the second output pipe 51.

[0036] In the embodiment of the present application, a condensation structure is provided on the first condenser 2 and the second condenser 5 , and a cooling water supply pipe 86 and a cooling water return pipe 87 are connected to the condensation structure for passing condensation water to cool the first condenser 2 and the second condenser 5 .

[0037] The glycolide recovery equipment provided in the embodiment of the present application shortens the transportation distance of glycolide tailings by arranging separator 3 at the bottom of evaporator 1 and directly connecting the bottom of evaporator 1 and separator 3 through a vertically arranged first receiving pipe 30, and directly connecting the bottom of separator 3 and reaction system 6 through a vertically arranged second receiving pipe 60. Compared with the multi-pipeline and multi-elbow connection in the prior art, it greatly reduces the risk of blockage of related pipelines and equipment between evaporator 1 and separator 3, and between separator 3 and reaction system 6; and through the primary recovery of evaporator 1 and first condenser 2, and the secondary recovery of separator 3 and separation tower 4, the solvent in the glycolide tailings is evaporated and recovered step by step, so as to realize full recovery and utilization of the solvent, and at the same time avoid the problem of excessive evaporation of solvent of glycolide tailings in evaporator 1, resulting in excessive viscosity that is not conducive to transportation.

[0038] In an optional embodiment, the glycolide recovery device further comprises a first circulation pipe 41 connected between the bottom of the separation tower 4 and the side of the separation tower 4, and a bottom pump 410 and a reboiler 411 are installed on the first circulation pipe 41. Figure 1 The first circulation pipe 41 can circulate the mixture of solvent and impurities at the bottom of the separation tower 4 to the side of the separation tower 4 again, wherein the tower bottom pump 410 plays a driving role, and the reboiler 411 heats the solvent and impurities in the first circulation pipe 41, so that the heated solvent and impurities enter the separation tower 4 and are separated again, thereby improving the solvent recovery effect.

[0039] The reboiler 411 is provided with a heat exchange structure, and a steam liquid inlet pipe 84 and a steam liquid outlet pipe 85 are connected to the heat exchange structure so that steam can be introduced to heat the reboiler 411 .

[0040] In an optional embodiment, the glycolide recovery device further includes a controller, a second circulation pipe 42 and a liquid level sensor. The second circulation pipe 42 is connected between the first circulation pipe 41 and the side of the separator 3, the liquid level sensor is installed on the separation tower 4 to monitor the solvent level in the separation tower 4, and a control valve is provided on the second circulation pipe 42. The controller is in communication connection with the liquid level sensor and the control valve, so that when the liquid level sensor detects that the solvent level exceeds a preset threshold, the controller controls the control valve to open. In the embodiment of the present application, the control valve and the liquid level in the separation tower 4 are controlled in linkage, so that when the liquid level sensor detects that the liquid level in the separation tower 4 exceeds a preset threshold, such as 80% of the total height inside the separation tower 4, the control valve is opened to transport part of the material in the separation tower 4 to the separator 3 for re-separation, so as to ensure the pressure and liquid level safety of the separation tower 4. The liquid level sensor can be installed inside the separation tower 4 to effectively monitor the solvent level in the separation tower 4.

[0041] In an optional embodiment, the first condensing unit 21 includes a condensing tank 210, the top of the condensing tank 210 is connected to the bottom of the first condenser 2 through a condensing pipe 211, and the bottom of the condensing tank 210 is connected to the first output pipe 22. The condensing tank 210 in the embodiment of the present application plays a buffering role to avoid the problem of the driving pump on the first output pipe 22 being evacuated.

[0042] In an optional embodiment, the second condensing unit 50 includes a reflux tank 500, the bottom of the second condenser 5 is connected to the top of the reflux tank 500 through a reflux pipe 501, and the bottom of the reflux tank 500 is connected to the second output pipe 51. The reflux tank 500 in the embodiment of the present application plays a buffering role to avoid the problem of the driving pump on the second output pipe 51 being evacuated.

[0043] In an optional embodiment, the glycolide recovery device further includes a third circulation pipe 43, and the third circulation pipe 43 is connected between the second output pipe 51 and the top of the separation tower 4. The third circulation pipe 43 in the embodiment of the present application transmits part of the low-temperature solvent in the second output pipe 51 to the top of the separation tower 4, and cools the top of the separation tower 4, so that part of the gas phase impurities at the top of the separation tower 4 are condensed and fall back into the liquid phase solvent of the separation tower 4.

[0044] In an optional embodiment, the glycolide recovery device further includes a vacuum unit, which includes a first vacuum tube 70 connected to the side wall of the first condenser 2 and a second vacuum tube 71 connected to the second condenser 5, the first vacuum tube 70 is connected to a first vacuum pump 700, and the second vacuum tube 71 is connected to a second vacuum pump 710. In the embodiment of the present application, the vacuum degree of the system is controlled by the vacuum unit to control the recovery of the solvent.

[0045] In an optional embodiment, a first heating unit for heating glycolide tailings is provided in the evaporator 1 or on the outer wall of the evaporator 1, and a second heating unit for heating glycolide tailings is provided in the separator 3 or on the outer wall of the separator 3. In the embodiment of the present application, the first heating unit can heat and evaporate the glycolide tailings in the evaporator 1, so that the solvent and the glycolide tailings are separated once, and the second heating unit can heat and evaporate the glycolide tailings in the separator 3, so that the solvent and the glycolide tailings are separated twice.

[0046] In an optional embodiment, the first heating unit includes a first heat exchange jacket disposed outside the evaporator 1, and the first heat exchange jacket is connected to a heat exchange liquid inlet pipe 80 and a heat exchange liquid outlet pipe 81. Steam or other heating medium enters the first heat exchange jacket from the heat exchange liquid inlet pipe 80 and flows out from the heat exchange liquid outlet pipe 81, and in this process, the evaporator 1 is heated. The second heating unit includes a second heat exchange jacket disposed outside the separator 3, and the second heat exchange jacket is connected to a heat transfer oil upper oil pipe 82 and a heat transfer oil return oil pipe 83. Hot oil enters the second jacket from the heat transfer oil upper oil pipe 82 and flows out from the heat transfer oil return oil pipe 83, and in this process, the separator 3 is heated.

[0047] The present application also provides a method for recovering glycolide, which recovers glycolide by the glycolide recovery equipment described in any of the above embodiments, and includes the following steps.

[0048] S1: feeding, the glycolide tail material is transported to the evaporator 1 through the feed pipe 10.

[0049] S2: primary recovery, wherein the glycolide tailings are evaporated in the evaporator 1, and the generated gaseous solvent is transported from the top of the evaporator 1 to the first condenser 2 through the first receiving pipe 20. The glycolide tailings evaporated and condensed in the evaporator 1 enter the separator 3 below through the vertically extending first receiving pipe 30 under the action of gravity and pressure difference.

[0050] S3: The gas phase solvent is condensed into a liquid phase solvent in the first condenser 2. The liquid phase solvent enters the first condensing unit 21 and is output through the first output pipe 22 on the side of the first condensing unit 21 when the liquid level reaches the preset liquid level.

[0051] S4: Secondary recovery, the glycolide tail material is evaporated again in the separator 3, and the gas phase solvent and part of the glycolide tail material enter the separation tower 4 through the second receiving pipe 40 to separate the gas phase solvent and impurities.

[0052] S5: Secondary recovery and external transportation, the separated gaseous solvent enters the second condenser 5 to be cooled into a liquid solvent, the liquid solvent enters the second condensing unit 50 and is output through the second output pipe 51 on the side of the second condensing unit 50 when the liquid level reaches the preset liquid level.

[0053] S6; receiving material, the reaction system 6 is located at the bottom of the separator 3 and is connected to the bottom of the separator 3 through a second receiving pipe 60 extending vertically to receive the glycolide tailings.

[0054] As needed, the above technical solutions can be combined to achieve the best technical effect.

[0055] The above are only the principles and preferred embodiments of the present invention. It should be noted that, for those skilled in the art, several other modifications can be made based on the principles of the present invention, which should also be considered as the protection scope of the present invention.

Claims

1. A glycolide recovery device, characterized in that: include: Evaporator, used to receive glycolide tailings; A first condenser is connected to the evaporator through a first receiving tube to receive the gas phase solvent, and a first condensing unit is also connected to the bottom of the first condenser, and the first condensing unit is connected to a first output tube to output the condensed liquid phase solvent; A separator, located at the bottom of the evaporator and directly connected to the bottom of the evaporator through a vertically extending first receiving pipe; A separation tower connected to the separator through a second receiving pipe, the separation tower is connected to a second condenser through a delivery pipe, the second condenser is further connected to a second condensing unit, and the second condensing unit is connected to a second output pipe to output the condensed liquid solvent; The reaction system is located at the bottom of the separator and is connected to the bottom of the separator through a second vertically extending receiving pipe to receive glycolide tailings.

2. The glycolide recovery equipment according to claim 1, characterized in that: The glycolide recovery device further comprises a first circulation pipe connected between the bottom of the separation tower and the side of the separation tower; The first circulation pipe is equipped with a tower kettle pump and a reboiler.

3. The glycolide recovery equipment according to claim 2, characterized in that: The glycolide recovery device also includes a controller, a second circulation pipe and a liquid level sensor; The second circulation pipe is connected between the first circulation pipe and the side of the separator, the liquid level sensor is installed on the separation tower to monitor the solvent level in the separation tower, and a control valve is provided on the second circulation pipe; The controller is in communication connection with the liquid level sensor and the control valve, so that when the liquid level sensor detects that the solvent level exceeds a preset threshold, the controller controls the control valve to open.

4. The glycolide recovery equipment according to claim 1, characterized in that: The first condensing unit comprises a condensing tank, the top of which is connected to the bottom of the first condenser via a condensing pipe, and the bottom of the condensing tank is connected to the first output pipe.

5. The glycolide recovery equipment according to claim 1, characterized in that: The second condensing unit includes a reflux drum; The bottom of the second condenser is connected to the top of the reflux tank through a reflux pipe, and the bottom of the reflux tank is connected to the second output pipe.

6. The glycolide recovery equipment according to claim 5, characterized in that: The glycolide recovery device also includes a third circulation pipe, which is connected between the second output pipe and the top of the separation tower.

7. The glycolide recovery equipment according to claim 1, characterized in that: The glycolide recovery device further comprises a vacuum unit, wherein the vacuum unit comprises a first vacuum tube connected to the side wall of the first condenser and a second vacuum tube connected to the second condenser; The first vacuum tube is connected to a first vacuum pump, and the second vacuum tube is connected to a second vacuum pump.

8. The glycolide recovery device according to any one of claims 1 to 7, characterized in that: A first heating unit for heating glycolide tailings is provided in the evaporator or on the outer wall of the evaporator, and a second heating unit for heating glycolide tailings is provided in the separator or on the outer wall of the separator.

9. The glycolide recovery equipment according to claim 8, characterized in that: The first heating unit comprises a first heat exchange jacket arranged outside the evaporator, and the first heat exchange jacket is connected to a heat exchange liquid inlet pipe and a heat exchange liquid outlet pipe; The second heating unit comprises a second heat exchange jacket arranged outside the separator, and a heat transfer oil upper pipe and a heat transfer oil return pipe are connected to the second heat exchange jacket.

10. A method for recovering glycolide, comprising: recovering glycolide by using the glycolide recovery device according to any one of claims 1 to 9, comprising: Feeding, conveying the glycolide tail material to the evaporator through a feed pipe; The first-stage recovery is to evaporate the glycolide tail material in the evaporator, and the generated gas phase solvent is transported from the top of the evaporator to the first condenser through the first receiving pipe. The glycolide tail material evaporated and condensed in the evaporator enters the separator below through the vertically extending first receiving pipe under the action of gravity and pressure difference; The gas phase solvent is condensed into a liquid phase solvent in the first condenser, and the liquid phase solvent enters the first condensing unit and is output through the first output pipe on the side of the first condensing unit when the liquid level reaches the preset liquid level; Secondary recovery, the glycolide tail material is evaporated again in the separator, and the gas phase solvent and part of the glycolide tail material enter the separation tower through the second receiving pipe to separate the gas phase solvent and impurities; Secondary recovery is transported outward, the separated gas phase solvent enters the second condenser to be cooled into liquid phase solvent, the liquid phase solvent enters the second condensing unit and is output through the second output pipe on the side of the second condensing unit when the liquid level reaches the preset liquid level; The reaction system is located at the bottom of the separator and is connected to the bottom of the separator through a second vertically extending receiving pipe to receive the glycolide tailings.

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