Tetrahydrofuran recycling system

Abstract

The utility model discloses a tetrahydrofuran recycling system, relates to the technical field of tetrahydrofuran production, and mainly aims to recycle tetrahydrofuran condensate and improve production benefits. According to the main technical scheme, the tetrahydrofuran recycling system comprises a stripping tower, a recycling fan and a rectification unit, the upper end of the stripping tower is connected to an inlet of the condenser; an inlet of the recovery fan is connected to a gas phase outlet of the condenser, an outlet of the recovery fan is connected to a heat medium furnace, and the lower end of a volute of the recovery fan is connected to the upper end of the liquid storage tank through a first return pipe; and a feed port of the rectification unit is connected to the lower end of the liquid storage tank.

Description

Technical Field

[0001] The utility model relates to the technical field of tetrahydrofuran production, in particular to a tetrahydrofuran recovery and utilization system. Background Art

[0002] Tetrahydrofuran (THF) is a commonly used organic solvent and is widely used in industrial production. However, the volatility and toxicity of tetrahydrofuran make the treatment of its tail gas an important issue. In order to protect the environment and save energy, it is very necessary to recover and treat the tetrahydrofuran tail gas.

[0003] The tail gas generated during the production of the tetrahydrofuran recovery device is collected by the tail gas fan of the tetrahydrofuran device. When the tail gas fan recovers the tail gas, condensate will be generated inside the volute of the tail gas fan. Currently, the condensate inside the volute of the tail gas fan is usually recovered manually on site. However, this treatment method increases the labor force of personnel, and there are risks such as personnel falling and high-altitude falling when carrying condensate down the stairs, and it also makes the operators directly contact toxic and harmful gases. Moreover, there will be problems such as the condensate flowing into the main device esterification tail gas fan causing the fan to trip, the tail gas being discharged causing environmental protection incidents and abnormal production of the device, and the condensate flowing into the heat medium furnace, resulting in excessive nitrogen oxides.

[0004] Therefore, a condensate recovery system for the volute of the tail gas fan of the tetrahydrofuran recovery unit is needed to improve the above problems. Summary of the Utility Model

[0005] In view of this, the embodiment of the utility model provides a tetrahydrofuran recovery and utilization system, and the main purpose is to recover and utilize tetrahydrofuran condensate to improve production efficiency.

[0006] To achieve the above purpose, the utility model mainly provides the following technical solutions:

[0007] The embodiment of the utility model provides a tetrahydrofuran recovery and utilization system, which includes: a stripping tower, a recovery fan and a rectification unit;

[0008] The upper end of the stripping tower is connected to the inlet of the condenser;

[0009] The inlet of the recovery fan is connected to the gas-phase outlet of the condenser, the outlet of the recovery fan is connected to the heat medium furnace, and the lower end of the volute of the recovery fan is connected to the upper end of the liquid storage tank through a first return pipe;

[0010] The feed inlet of the rectification unit is connected to the lower end of the liquid storage tank.

[0011] The purpose of the utility model and the solution of its technical problems can be further realized by adopting the following technical measures.

[0012] Optionally, the first reflux pipe is provided with a U-shaped pipe section for forming a liquid seal effect.

[0013] Optionally, a check valve is further included. The check valve is installed on the first reflux pipe, the inlet of the check valve faces the recovery fan, and the outlet of the check valve faces the liquid storage tank.

[0014] Optionally, the liquid phase outlet of the condenser is connected to the upper end of the liquid storage tank.

[0015] Optionally, the rectification unit includes a primary rectification tower, a secondary rectification tower, and a purification tower arranged in sequence.

[0016] Optionally, the lower end of the liquid storage tank is connected to the feed inlet on the side wall of the primary rectification tower through a first feed pipe. The bottom of the primary rectification tower is connected to the feed inlet on the upper side of the stripping tower through a first discharge pipe. The first feed pipe communicates with the first space of the first heat exchanger, and the first discharge pipe communicates with the second space of the first heat exchanger.

[0017] Optionally, the upper end of the primary rectification tower is sequentially connected to the inlet of a first cooler, a first condensate tank, and a first liquid delivery pump. The outlet of the first liquid delivery pump is respectively connected to one end of a second reflux pipe and one end of a second feed pipe. The other end of the second reflux pipe is connected to the upper side of the primary rectification tower. The other end of the second feed pipe is connected to the feed inlet on the side wall of the secondary rectification tower. The bottom of the secondary rectification tower is connected to the feed inlet on the side wall of the purification tower through a second discharge pipe. The second feed pipe communicates with the first space of the second heat exchanger, and the second discharge pipe communicates with the second space of the second heat exchanger.

[0018] Optionally, the upper end of the secondary rectification tower is sequentially connected to the inlet of a second cooler, a second condensate tank, and a second liquid delivery pump. The outlet of the second liquid delivery pump is respectively connected to one end of a third reflux pipe and one end of a return pipe. The other end of the third reflux pipe is connected to the upper side of the secondary rectification tower. The other end of the return pipe is connected to the side wall of the primary rectification tower.

[0019] Optionally, the upper end of the purification tower is sequentially connected to the inlet of a third cooler, a third condensate tank, and a third liquid delivery pump. The outlet of the third liquid delivery pump is respectively connected to one end of a fourth reflux pipe and one end of a discharge pipe. The other end of the fourth reflux pipe is connected to the upper side of the purification tower. The other end of the discharge pipe is connected to a buffer tank. The bottom of the purification tower is sequentially connected to a discharge pump and an intermediate tank.

[0020] Optionally, a fourth cooler is further included. The fourth cooler is installed on the discharge pipe.

[0021] By means of the above technical solutions, the utility model has at least the following advantages:

[0022] The tail gas discharged from the upper end of the stripping column of the recovery unit is cooled by a condenser. The purity of the uncondensed tail gas is relatively low. This part of the tail gas enters the recovery fan and finally enters the heat medium furnace for combustion.

[0023] During the above process, condensate will be generated in the volute of the recovery fan. This part of the condensate enters the liquid storage tank through the first return pipe and then enters the rectification unit for further purification.

[0024] On the one hand, the recovery rate of the tetrahydrofuran condensate is improved, and the economic benefit is increased; on the other hand, it avoids the condensate of the tail gas from flowing into the esterification tail gas fan of the main unit, preventing the esterification tail gas fan from tripping. Description of the Drawings

[0025] Figure 1 It is a flow chart of a tetrahydrofuran recovery and utilization system provided by an embodiment of the present invention.

[0026] The reference numerals in the drawings of the specification include: stripping column 1, recovery fan 2, condenser 3, heat medium furnace 4, first return pipe 5, liquid storage tank 6, check valve 7, primary rectification column 8, secondary rectification column 9, purification column 10, first feed pipe 11, first discharge pipe 12, first heat exchanger 13, first transfer pump 14, second transfer pump 15, first cooler 16, first condensate tank 17, first liquid delivery pump 18, second return pipe 19, second feed pipe 20, second discharge pipe 21, second heat exchanger 22, second cooler 23, second condensate tank 24, second liquid delivery pump 25, third return pipe 26, return pipe 27, third cooler 28, third condensate tank 29, third liquid delivery pump 30, fourth return pipe 31, discharge pipe 32, buffer tank 33, discharge pump 34, intermediate tank 35, fourth cooler 36. Detailed Embodiments

[0027] To further elaborate on the technical means and effects adopted by the present invention to achieve the intended utility model purpose, the following combines the drawings and preferred embodiments to detail the specific embodiments, structures, features and their effects according to the present invention application. In the following description, different "one embodiment" or "embodiment" do not necessarily refer to the same embodiment. In addition, the specific features, structures, or characteristics in one or more embodiments can be combined in any suitable form.

[0028] The present invention will be further described in detail below with reference to the drawings and embodiments.

[0029] As Figure 1 shown, a tetrahydrofuran recovery and utilization system provided by an embodiment of the present invention includes: a stripping column 1, a recovery fan 2, and a rectification unit;

[0030] The upper end of the stripping column 1 is connected to the inlet of the condenser 3;

[0031] The inlet of the recovery fan 2 is connected to the gas-phase outlet of the condenser 3, the outlet of the recovery fan 2 is connected to the heat medium furnace 4, and the lower end of the volute of the recovery fan 2 is connected to the upper end of the liquid storage tank 6 through the first return pipe 5;

[0032] The feed inlet of the rectification unit is connected to the lower end of the liquid storage tank 6.

[0033] The working process of the tetrahydrofuran recovery and utilization system is as follows:

[0034] The tail gas discharged from the upper end of the stripping column 1 of the recovery unit is cooled by the condenser 3. The purity of the uncondensed tail gas is relatively low. This part of the tail gas enters the recovery fan 2 and finally enters the heat medium furnace 4 for combustion.

[0035] During the above process, condensate will be generated in the volute of the recovery fan 2. This part of the condensate enters the liquid storage tank 6 through the first return pipe 5 and then enters the rectification unit for further purification.

[0036] On the one hand, the recovery rate of the tetrahydrofuran condensate is improved, improving economic benefits; on the other hand, it avoids the condensate of the tail gas from flowing into the esterification tail gas fan of the main device, preventing the esterification tail gas fan from tripping.

[0037] Specifically, the outlet end of the recovery fan 2 and the outlet end of the esterification tail gas fan are convergently connected to the heat medium furnace 4.

[0038] In the specific embodiment, the first return pipe 5 is provided with a U-shaped pipe section for forming a liquid seal effect.

[0039] In this embodiment, specifically, the U-shaped pipe section always retains condensate to form a liquid seal effect, separating the volute of the recovery fan 2 from the liquid storage tank 6. In this way, even if there is no condensate in the volute of the recovery fan 2, when the recovery fan 2 is operating normally, the gas in the liquid storage tank 6 will not be sucked into the recovery fan 2.

[0040] In the specific embodiment, a check valve 7 is further included. The check valve 7 is installed on the first return pipe 5. The inlet of the check valve 7 faces the recovery fan 2, and the outlet of the check valve 7 faces the liquid storage tank 6.

[0041] In this embodiment, by setting the check valve 7, the condensate in the volute of the recovery fan 2 can enter the liquid storage tank 6, but the components in the liquid storage tank 6 cannot enter the recovery fan 2, further avoiding the recovery fan 2 from sucking the components in the liquid storage tank 6.

[0042] In the specific embodiment, the liquid-phase outlet of the condenser 3 is connected to the upper end of the liquid storage tank 6.

[0043] In this embodiment, specifically, after the tail gas discharged from the top of the stripping column 1 is cooled by the condenser 3, the uncondensed and liquefied components enter the recovery fan 2 through the gas-phase outlet, and the condensed and liquefied components are discharged into the liquid storage tank 6 through the liquid-phase outlet, reducing the load of the recovery fan 2 and improving the recovery efficiency of the condensate.

[0044] Specifically, the condenser 3 adopts a horizontal shell-and-tube heat exchanger. One end of the tube side of the horizontal shell-and-tube heat exchanger is connected to the upper end of the stripping column 1. The upper side of the other end of the tube side of the horizontal shell-and-tube heat exchanger is the gas-phase outlet, and the lower side of the other end of the tube side of the horizontal shell-and-tube heat exchanger is the liquid-phase outlet.

[0045] In a specific embodiment, the rectification unit includes a primary rectification column 8, a secondary rectification column 9, and a purification column 10 arranged in sequence.

[0046] In this embodiment, specifically, the condensate in the liquid storage tank 6 is rectified successively through the primary rectification column 8, the secondary rectification column 9, and the purification column 10, improving the purity of tetrahydrofuran.

[0047] In a specific embodiment, the lower end of the liquid storage tank 6 is connected to the feed port on the side wall of the primary rectification column 8 through the first feed pipe 11. The bottom of the primary rectification column 8 is connected to the feed port on the upper side of the stripping column 1 through the first discharge pipe 12. The first feed pipe 11 communicates with the first space of the first heat exchanger 13, and the first discharge pipe 12 communicates with the second space of the first heat exchanger 13.

[0048] In this embodiment, specifically, the condensate in the liquid storage tank 6 enters the primary rectification column 8 through the first feed pipe 11, and the heavy components therein return to the stripping column 1 through the first discharge pipe 12. In the above process, the condensate and the heavy components complete heat transfer in the first heat exchanger 13, improving the thermal efficiency.

[0049] Specifically, it further includes a first transfer pump 14 and a second transfer pump 15. The first transfer pump 14 is installed on the first feed pipe 11, and the second transfer pump 15 is installed on the first discharge pipe 12.

[0050] In a specific embodiment, the upper end of the primary rectification column 8 is sequentially connected to the inlet of the first cooler 16, the first condensate tank 17, and the first liquid delivery pump 18. The outlet of the first liquid delivery pump 18 is respectively connected to one end of the second return pipe 19 and one end of the second feed pipe 20. The other end of the second return pipe 19 is connected to the upper side of the primary rectification column 8, and the other end of the second feed pipe 20 is connected to the feed port on the side wall of the secondary rectification column 9. The bottom of the secondary rectification column 9 is connected to the feed port on the side wall of the purification column 10 through the second discharge pipe 21. The second feed pipe 20 communicates with the first space of the second heat exchanger 22, and the second discharge pipe 21 communicates with the second space of the second heat exchanger 22.

[0051] In this embodiment, specifically, the light components in the primary rectification column 8 are cooled by the first cooler 16, enter the first condensate tank 17, are pressurized by the first liquid delivery pump 18, a part of the light components are refluxed to the primary rectification column 8, and the other part of the light components enter the secondary rectification column 9. The heavy components of the secondary rectification column 9 enter the purification column 10 for further rectification and purification; in the above process, the feed and the bottom discharge of the secondary rectification column 9 complete heat exchange in the second heat exchanger 22 to improve the thermal efficiency.

[0052] In a specific embodiment, the upper end of the secondary rectification column 9 is sequentially connected to the inlets of the second cooler 23, the second condensate tank 24, and the second liquid delivery pump 25. The outlet of the second liquid delivery pump 25 is respectively connected to one end of the third reflux pipe 26 and one end of the return pipe 27. The other end of the third reflux pipe 26 is connected to the upper side of the secondary rectification column 9, and the other end of the return pipe 27 is connected to the side wall of the primary rectification column 8.

[0053] In this embodiment, specifically, the light components discharged from the upper end of the secondary rectification column 9 are condensed and cooled by the second cooler 23. The light component condensate settles to the second condensate tank 24 and is pressurized by the second liquid delivery pump 25. A part of the light components are refluxed to the secondary rectification column 9, and the other part of the light components are refluxed to the primary rectification column 8 for repeated rectification.

[0054] In a specific embodiment, the upper end of the purification column 10 is sequentially connected to the inlets of the third cooler 28, the third condensate tank 29, and the third liquid delivery pump 30. The outlet of the third liquid delivery pump 30 is respectively connected to one end of the fourth reflux pipe 31 and one end of the discharge pipe 32. The other end of the fourth reflux pipe 31 is connected to the upper side of the purification column 10. The other end of the discharge pipe 32 is connected to the buffer tank 33. The bottom of the purification column 10 is sequentially connected to the discharge pump 34 and the intermediate tank 35.

[0055] In this embodiment, specifically, the light components discharged from the upper end of the purification column 10 are condensed and cooled by the third cooler 28. The light component condensate settles to the third condensate tank 29 and is pressurized by the third liquid delivery pump 30. A part of the light components are refluxed to the purification column 10, and the other part of the light components enter the buffer tank 33 as finished products and are finally pumped to the THF finished product tank area;

[0056] The bottom discharge of the purification column 10 is high-boiling impurities, which are pumped to the intermediate tank 35 by the discharge pump 34 for subsequent re-rectification and recovery.

[0057] In a specific embodiment, it further includes a fourth cooler 36, and the fourth cooler 36 is installed on the discharge pipe 32.

[0058] In this embodiment, specifically, on the basis of the third cooler 28 condensing and cooling the light components, the fourth cooler 36 further condenses and cools the light components so as to reduce the finished product in the buffer tank 33 to an appropriate temperature.

[0059] The above are only specific embodiments of the present invention, but the protection scope of the present invention is not limited thereto. Any person skilled in the art within the technical scope disclosed by the present invention can easily think of changes or substitutions, which should all be covered within the protection scope of the present invention. Therefore, the protection scope of the present invention shall be subject to the protection scope of the claims.

Claims

1. A tetrahydrofuran recovery and utilization system, characterized in that: include: a stripping tower, wherein the upper end of the stripping tower is connected to the inlet of the condenser; A recovery fan, wherein the inlet of the recovery fan is connected to the gas phase outlet of the condenser, the outlet of the recovery fan is connected to the heat medium furnace, and the lower end of the volute of the recovery fan is connected to the upper end of the liquid storage tank through a first reflux pipe; A distillation unit, wherein the feed inlet of the distillation unit is connected to the lower end of the liquid storage tank.

2. The tetrahydrofuran recovery and utilization system according to claim 1, characterized in that: The first reflux pipe is provided with a U-shaped pipe section for forming a liquid sealing effect.

3. The tetrahydrofuran recovery and utilization system according to claim 1, characterized in that: It also includes a check valve, which is installed on the first return pipe, with an inlet of the check valve facing the recovery fan and an outlet of the check valve facing the liquid storage tank.

4. The tetrahydrofuran recovery and utilization system according to claim 1, characterized in that: The liquid phase outlet of the condenser is connected to the upper end of the liquid storage tank.

5. The tetrahydrofuran recovery and utilization system according to any one of claims 1 to 4, characterized in that: The distillation unit comprises a primary distillation tower, a secondary distillation tower and a purification tower which are arranged in sequence.

6. The tetrahydrofuran recovery and utilization system according to claim 5, characterized in that: The lower end of the liquid storage tank is connected to the feed port on the side wall of the primary distillation tower through a first feed pipe, the bottom of the primary distillation tower is connected to the feed port on the upper end side of the stripping tower through a first discharge pipe, the first feed pipe is connected to the first space of the first heat exchanger, and the first discharge pipe is connected to the second space of the first heat exchanger.

7. The tetrahydrofuran recovery and utilization system according to claim 6, characterized in that: The upper end of the primary distillation tower is connected to the first cooler, the first condensate tank and the inlet of the first infusion pump in sequence, the outlet of the first infusion pump is respectively connected to one end of the second reflux pipe and one end of the second feed pipe, the other end of the second reflux pipe is connected to the upper end side of the primary distillation tower, the other end of the second feed pipe is connected to the feed port of the side wall of the secondary distillation tower, the bottom of the secondary distillation tower is connected to the feed port of the side wall of the purification tower through the second discharge pipe, the second feed pipe is connected to the first space of the second heat exchanger, and the second discharge pipe is connected to the second space of the second heat exchanger.

8. The tetrahydrofuran recovery and utilization system according to claim 7, characterized in that: The upper end of the secondary distillation tower is connected to the second cooler, the second condensate tank and the inlet of the second infusion pump in sequence, the outlet of the second infusion pump is respectively connected to one end of the third reflux pipe and one end of the return pipe, the other end of the third reflux pipe is connected to the upper end side of the secondary distillation tower, and the other end of the return pipe is connected to the side wall of the primary distillation tower.

9. The tetrahydrofuran recovery and utilization system according to claim 7, characterized in that: The upper end of the purification tower is connected to the inlet of the third cooler, the third condensate tank and the third infusion pump in sequence, the outlet of the third infusion pump is respectively connected to one end of the fourth reflux pipe and one end of the discharge pipe, the other end of the fourth reflux pipe is connected to the upper end side of the purification tower, the other end of the discharge pipe is connected to the buffer tank, and the bottom of the purification tower is connected to the discharge pump and the intermediate tank in sequence.

10. The tetrahydrofuran recovery and utilization system according to claim 9, characterized in that: It also includes a fourth cooler, which is installed on the discharge pipe.

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