System for preparing high-purity tetrahydrofuran from 1, 4-butanediol waste liquid

Abstract

The utility model discloses a system for preparing high-purity tetrahydrofuran from 1, 4-butanediol waste liquid, which comprises a heavy phase separation device, a reaction device, a neutralization device, an azeotropic rectification device, a dehydration device, a light component removal rectification device and a finished product rectification device, the heavy phase separation device, the reaction device, the neutralization device, the azeotropic rectification device, the dehydration device, the light component removal rectification device and the finished product rectification device are connected in sequence; according to the device, high-purity tetrahydrofuran can be obtained from the 1, 4-butanediol waste liquid by utilizing a combined process of reaction, membrane separation, rectification and the like; the conversion rate of the reaction process is high, the refining process is embedded into a membrane separation technology capable of breaking azeotropic limitation, the service life of the membrane is long, and the energy consumption of process operation is low.

Description

Technical Field

[0001] This utility model relates to the field of chemical production technology, specifically to a system for preparing high-purity tetrahydrofuran from 1,4-butanediol waste liquid. Background Technology

[0002] 1,4-Butanediol (BDO) is an important organic chemical raw material, initially used primarily to prepare butadiene, a monomer for synthetic rubber. Currently, its downstream industrial chains mainly include tetrahydrofuran-polytetrahydrofuran-spandex, polybutylene terephthalate, γ-butyrolactone-N-methylpyrrolidone, polyurethane, poly(butylene adipate / terephthalate), and polybutylene succinate, among others. The tetrahydrofuran-polytetrahydrofuran-spandex industrial chain accounts for over 50% of consumption. In recent years, with the continuous increase in demand for spandex, biodegradable materials, and new energy lithium batteries, BDO production capacity has also been steadily increasing.

[0003] The acetylacetonate-aldehyde process is currently the most widely used technology for BDO production. This process consists of a formaldehyde stage, an acetylacetonate stage, a hydrogenation stage, and a refining stage. The refining stage uses salt towers, low-boiling towers, and high-boiling towers to repeatedly remove impurities from the concentrated BDO, achieving purification and separating qualified BDO products. This purification process generates a large amount of BDO-containing wastewater, in which the BDO itself has potential for further utilization. However, the BDO wastewater contains complex components, including those with similar volatility to BDO or forming azeotropic reactions, making further separation difficult and uneconomical. When BDO market prices are low, deep separation and purification of the wastewater to obtain qualified BDO products for sale lacks market competitiveness. Therefore, developing high-value-added methods for the resource utilization of BDO wastewater can further improve the economic benefits for enterprises. Utility Model Content

[0004] In view of this, the present invention aims to provide a system for preparing high-purity tetrahydrofuran from 1,4-butanediol waste liquid, which can obtain high-purity tetrahydrofuran from 1,4-butanediol waste liquid using a combination of processes such as reaction, membrane separation, and distillation.

[0005] To achieve the above objectives, the technical solution of this utility model is implemented as follows:

[0006] This invention provides a system for preparing high-purity tetrahydrofuran from 1,4-butanediol waste liquid, comprising a heavy phase separation device, a reaction device, a neutralization device, an azeotropic distillation device, a dehydration device, a light-light distillation device, and a finished product distillation device, wherein the heavy phase separation device, the reaction device, the neutralization device, the azeotropic distillation device, the dehydration device, the light-light distillation device, and the finished product distillation device are connected in sequence.

[0007] Furthermore, the heavy phase separation device includes a raw material tank, a raw material pump, a scraped film evaporator, a heavy phase tank, a first condenser, a first vacuum pump, and a light phase tank; the raw material tank is connected to the scraped film evaporator via the raw material pump, the bottom of the scraped film evaporator is connected to the heavy phase tank, the top of the scraped film evaporator is connected to the first condenser, the first condenser is connected to the first vacuum pump and the light phase tank respectively, and the light phase tank is connected to the reaction device.

[0008] Further, the reaction apparatus includes a reactor feed pump, a reactor, a catalyst tank, a catalyst pump, a reactor tower, a second condenser, a first reflux tank, a first reflux pump, a first tower top pump, a reaction distillate tank, a reactor pump, a first cooler, and a reactor residue tank. The light phase tank is connected to the reactor via the reactor feed pump, the catalyst tank is connected to the reactor via the catalyst pump, the top of the reactor is connected to the reactor tower, the bottom of the reactor tower is also connected to the reactor, the top of the reactor tower is connected to the second condenser, the second condenser is connected to the first reflux tank, the first reflux tank is connected to both the first reflux pump and the first tower top pump, the first reflux pump is connected to the reactor tower, the first tower top pump is connected to the reaction distillate, the bottom of the reactor is connected to the first cooler via the reactor pump, the first cooler is connected to the reactor residue tank, and the reaction distillate tank is connected to the neutralization device.

[0009] Furthermore, the neutralization device includes a neutralization kettle feed pump, a neutralization kettle, an alkali pump, an alkali tank, a neutralization kettle discharge pump, and a mixing tank; the reaction distillate tank is connected to the neutralization kettle via the neutralization kettle feed pump, the alkali tank is connected to the neutralization kettle via the alkali pump, the bottom of the neutralization kettle is connected to the mixing tank via the neutralization kettle discharge pump, and the mixing tank is connected to the azeotropic distillation device.

[0010] Further, the azeotropic distillation apparatus includes an azeotropic column feed pump, an azeotropic distillation column, a third condenser, a second reflux tank, a second reflux pump, a second top-of-column pump, an azeotropic liquid tank, a first reboiler, a first bottom-of-column pump, a second cooler, and a wastewater tank. The mixing tank is connected to the azeotropic distillation column via the azeotropic column feed pump. The top of the azeotropic distillation column is connected to the third condenser. The third condenser is connected to the second reflux tank. The second reflux tank is connected to both the second reflux pump and the second top-of-column pump. The second reflux pump is connected to the azeotropic distillation column. The second top-of-column pump is connected to the azeotropic liquid tank. One end of the first reboiler is connected to the lower part of the azeotropic distillation column, and the other end is connected to both the bottom pipe of the azeotropic distillation column and the first bottom-of-column pump. The first bottom-of-column pump is connected to the second cooler. The second cooler is connected to the wastewater tank. The azeotropic liquid tank is connected to the dehydration device.

[0011] Further, the dehydration device includes a membrane module feed pump, a heater, a membrane module, a fourth condenser, a second vacuum pump, a permeate tank, a permeate pump, a third cooler, and a dehydration tank; the azeotropic tank is connected to the heater via the membrane module feed pump, the heater is connected to the membrane module, one end of the membrane module is connected to the fourth condenser, the fourth condenser is connected to both the second vacuum pump and the permeate tank, the permeate tank is connected to the mixing tank via the permeate pump, the other end of the membrane module is connected to the third cooler, the third cooler is connected to the dehydration tank, and the dehydration tank is connected to the light distillation unit.

[0012] Further, the light-weight distillation unit includes a light-weight distillation column feed pump, a light-weight distillation column, a fifth condenser, a third reflux tank, a third reflux pump, a third column top outlet pump, a light-weight waste tank, a second reboiler, a second column bottom outlet pump, a fourth cooler, and a light-weight liquid tank. The dehydrated liquid tank is connected to the light-weight distillation column via the light-weight distillation column feed pump. The top of the light-weight distillation column is connected to the fifth condenser. The fifth condenser is connected to the third reflux tank. The third reflux tank is connected to both the third reflux pump and the third column top outlet pump. The third reflux pump is connected to the light-weight distillation column. The third column top outlet pump is connected to the light-weight waste tank. One end of the second reboiler is connected to the lower part of the light-weight distillation column, and the other end is connected to both the bottom pipe of the light-weight distillation column and the second column bottom outlet pump. The second column bottom outlet pump is connected to the fourth cooler. The fourth cooler is connected to the light-weight liquid tank. The light-weight liquid tank is connected to the finished product distillation unit.

[0013] Further, the finished product distillation unit includes a finished product column feed pump, a finished product distillation column, a sixth condenser, a fourth reflux tank, a fourth reflux pump, a fourth column top-out pump, a finished product tank, a third reboiler, a third column bottom-out pump, a fifth cooler, and a heavy / mixed liquid tank; the light liquid removal tank is connected to the finished product distillation column via the finished product column feed pump; the finished product distillation column is connected to the sixth condenser; the sixth condenser is connected to the fourth reflux tank; the fourth reflux tank is connected to both the fourth reflux pump and the fourth column top-out pump; the fourth reflux pump is connected to the finished product distillation column; the fourth column top-out pump is connected to the finished product tank; one end of the third reboiler is connected to the lower part of the finished product distillation column, and the other end is connected to both the bottom pipe of the finished product distillation column and the third column bottom-out pump; the third column bottom-out pump is connected to the fifth cooler; and the fifth cooler is connected to the heavy / mixed liquid tank.

[0014] The beneficial effects of this utility model are as follows:

[0015] (1) This utility model utilizes a combination of a reaction vessel and a distillation tower to continuously convert 1,4-butanediol in waste liquid into high-value-added tetrahydrofuran under acidic conditions. The process is simple and the conversion rate is high.

[0016] (2) This invention adjusts the pH of the reaction distillate by adding alkali, thereby controlling the trace amounts of acid and aldehyde in the reaction distillate. This not only achieves the purpose of partial impurity removal, but also effectively eliminates the damage of acidic substances to the membrane in the subsequent membrane module, greatly improving the service life of the membrane.

[0017] (3) This utility model couples membrane separation and distillation process for the purification of tetrahydrofuran after reaction, breaking the limitation of tetrahydrofuran and water azeotropic reaction. Compared with traditional special distillation process, energy consumption is also greatly reduced. Attached Figure Description

[0018] Figure 1 This is a schematic diagram of the system structure for preparing high-purity tetrahydrofuran from 1,4-butanediol waste liquid according to this utility model.

[0019] The components include: 1. Raw material tank; 2. Raw material pump; 3. Scraped film evaporator; 4. Heavy phase tank; 5. First condenser; 6. First vacuum pump; 7. Light phase tank; 8. Reactor feed pump; 9. Reactor; 10. Catalyst tank; 11. Catalyst pump; 12. Reactor column; 13. Second condenser; 14. First reflux tank; 15. First reflux pump; 16. First column top pump; 17. Reaction distillate tank; 18. Reactor top product tank. Pumps; 19. First Cooler; 20. Residual Liquid Tank of Reactor; 21. Feed Pump for Neutralization Reactor; 22. Neutralization Reactor; 23. Alkali Pump; 24. Alkali Tank; 25. Discharge Pump for Neutralization Reactor; 26. Mixing Tank; 27. Feed Pump for Azeotropic Column; 28. Azeotropic Distillation Column; 29. ​​Third Condenser; 30. Second Reflux Tank; 31. Second Reflux Pump; 32. Second Column Top Discharge Pump; 33. Azeotropic Liquid Tank; 34. First Reboiler; 35. First Column 36. Second Cooler; 37. Wastewater Tank; 38. Membrane Module Feed Pump; 39. Heater; 40. Membrane Module; 41. Fourth Condenser; 42. Second Vacuum Pump; 43. Permeate Tank; 44. Permeate Pump; 45. Third Cooler; 46. Dehydrated Liquid Tank; 47. Light Light Distillation Column Feed Pump; 48. Light Light Distillation Column; 49. Fifth Condenser; 50. Third Reflux Tank; 51. Third Reflux Pump; 52. Third Column 53. Top pump; 54. Light liquid tank; 55. Second reboiler; 56. Second column bottom pump; 57. Fourth cooler; 58. Light liquid removal tank; 59. Finished product column feed pump; 60. Finished product distillation column; 61. Sixth condenser; 62. Fourth reflux tank; 63. Fourth reflux pump; 64. Fourth column top pump; 65. Finished product tank; 66. Third reboiler; 67. Third column bottom pump; 68. Fifth cooler; 69. Heavy liquid tank. Detailed Implementation

[0020] To provide a more detailed understanding of the features and technical content of this utility model, the implementation of this utility model will be described in detail below with reference to the accompanying drawings. The accompanying drawings are for reference and illustration only and are not intended to limit this utility model.

[0021] like Figure 1 As shown in the figure, a system for preparing high-purity tetrahydrofuran from 1,4-butanediol waste liquid according to an embodiment of the present invention includes a heavy phase separation device, a reaction device, a neutralization device, an azeotropic distillation device, a dehydration device, a light-light distillation device, and a product distillation device, wherein the heavy phase separation device, the reaction device, the neutralization device, the azeotropic distillation device, the dehydration device, the light-light distillation device, and the product distillation device are connected in sequence.

[0022] The heavy phase separation device includes a raw material tank 1, a raw material pump 2, a scraped film evaporator 3, a heavy phase tank 4, a first condenser 5, a first vacuum pump 6, and a light phase tank 7.

[0023] The reaction apparatus includes a reactor feed pump 8, a reactor 9, a catalyst tank 10, a catalyst pump 11, a reactor tower 12, a second condenser 13, a first reflux tank 14, a first reflux pump 15, a first tower top pump 16, a reaction distillate tank 17, a reactor outlet pump 18, a first cooler 19, and a reactor residue tank 20.

[0024] The neutralization device includes a neutralization kettle feed pump 21, a neutralization kettle 22, an alkali pump 23, an alkali tank 24, a neutralization kettle discharge pump 25, and a mixing tank 26.

[0025] The azeotropic distillation apparatus includes an azeotropic column feed pump 27, an azeotropic distillation column 28, a third condenser 29, a second reflux tank 30, a second reflux pump 31, a second column top pump 32, an azeotropic liquid tank 33, a first reboiler 34, a first column bottom pump 35, a second cooler 36, and a wastewater tank 37.

[0026] The dehydration device includes a membrane module feed pump 38, a heater 39, a membrane module 40, a fourth condenser 41, a second vacuum pump 42, a permeate tank 43, a permeate pump 44, a third cooler 45, and a dehydration tank 46.

[0027] The light-light distillation unit includes a light-light distillation column feed pump 47, a light-light distillation column 48, a fifth condenser 49, a third reflux tank 50, a third reflux pump 51, a third column top pump 52, a light impurity tank 53, a second reboiler 54, a second column bottom pump 55, a fourth cooler 56, and a light-light liquid tank 57.

[0028] The finished product distillation unit includes a finished product column feed pump 58, a finished product distillation column 59, a sixth condenser 60, a fourth reflux tank 61, a fourth reflux pump 62, a fourth column top pump 63, a finished product tank 64, a third reboiler 65, a third column bottom pump 66, a fifth cooler 67, and a heavy waste tank 68.

[0029] The raw material tank 1 is connected to the scraped film evaporator 3 via the raw material pump 2. The bottom of the scraped film evaporator 3 is connected to the heavy phase tank 4, and the top of the scraped film evaporator 3 is connected to the first condenser 5. The first condenser 5 is connected to the first vacuum pump 6 and the light phase tank 7 respectively.

[0030] The light phase tank 7 is connected to the reactor 9 via the reactor feed pump 8. The catalyst tank 10 is connected to the reactor 9 via the catalyst pump 11. The top of the reactor 9 is connected to the reactor tower 12, and the bottom of the reactor tower 12 is also connected to the reactor 9. The top of the reactor tower 12 is connected to the second condenser 13. The second condenser 13 is connected to the first reflux tank 14. The first reflux tank 14 is connected to the first reflux pump 15 and the first tower top pump 16. The first reflux pump 15 is connected to the reactor tower 12. The first tower top pump 16 is connected to the reaction distillate tank 17. The bottom of the reactor 9 is connected to the first cooler 19 via the reactor pump 18. The first cooler 19 is connected to the reactor residue tank 20.

[0031] The reaction distillate tank 17 is connected to the neutralization vessel 22 via the neutralization vessel feed pump 21, the alkali tank 24 is connected to the neutralization vessel 22 via the alkali pump 23, and the bottom of the neutralization vessel 22 is connected to the mixing tank 26 via the neutralization vessel discharge pump 25.

[0032] The mixing tank 26 is connected to the azeotropic distillation column 28 via the azeotropic column feed pump 27. The top of the azeotropic distillation column 28 is connected to the third condenser 29. The third condenser 29 is connected to the second reflux tank 30. The second reflux tank 30 is connected to the second reflux pump 31 and the second column top pump 32. The second reflux pump 31 is connected to the azeotropic distillation column 28. The second column top pump 32 is connected to the azeotropic liquid tank 33. One end of the first reboiler 34 is connected to the lower part of the azeotropic distillation column 28, and the other end is connected to the bottom pipe of the azeotropic distillation column 28 and the first column bottom pump 35. The first column bottom pump 35 is connected to the second cooler 36. The second cooler 36 is connected to the wastewater tank 37.

[0033] The azeotropic liquid tank 33 is connected to the heater 39 via the membrane module feed pump 38. The heater 39 is connected to the membrane module 40. One end of the membrane module 40 is connected to the fourth condenser 41. The fourth condenser 41 is connected to the second vacuum pump 42 and the permeate tank 43. The permeate tank 43 is connected to the mixing tank 26 via the permeate pump 44. The other end of the membrane module 40 is connected to the third cooler 45. The third cooler 45 is connected to the dehydration liquid tank 46.

[0034] The dehydrated liquid tank 46 is connected to the light-light distillation column 48 via the light-light distillation column feed pump 47. The top of the light-light distillation column 48 is connected to the fifth condenser 49. The fifth condenser 49 is connected to the third reflux tank 50. The third reflux tank 50 is connected to the third reflux pump 51 and the third column top pump 52. The third reflux pump 51 is connected to the light-light distillation column 48. The third column top pump 52 is connected to the light impurity tank 53. One end of the second reboiler 54 is connected to the lower part of the light-light distillation column 48, and the other end is connected to the bottom pipe of the light-light distillation column 48 and the second column bottom pump 55. The second column bottom pump 55 is connected to the fourth cooler 56. The fourth cooler 56 is connected to the light-light liquid tank 57.

[0035] The light liquid removal tank 57 is connected to the finished product distillation column 59 via the finished product column feed pump 58. The finished product distillation column 59 is connected to the sixth condenser 60. The sixth condenser 60 is connected to the fourth reflux tank 61. The fourth reflux tank 61 is connected to the fourth reflux pump 62 and the fourth column top pump 63. The fourth reflux pump 62 is connected to the finished product distillation column 59. The fourth column top pump 63 is connected to the finished product tank 64. One end of the third reboiler 65 is connected to the lower part of the finished product distillation column 59, and the other end is connected to the bottom pipe of the finished product distillation column 59 and the third column bottom pump 66. The third column bottom pump 66 is connected to the fifth cooler 67. The fifth cooler 67 is connected to the heavy impurity tank 68.

[0036] The specific workflow of this utility model embodiment is as follows:

[0037] The 1,4-butanediol waste liquid raw material placed in the raw material tank 1 is fed into the scraped film evaporator 3 through the raw material pump 2. The scraped film evaporator 3 operates under reduced pressure, with the negative pressure provided by the first vacuum pump 6. The scraped film evaporator 3 separates the heavy phase, such as salt and polymer, from the 1,4-butanediol waste liquid, separating it into the main body of the 1,4-butanediol waste liquid. After separation, the heavy phase enters the heavy phase tank 4, while the light phase of the 1,4-butanediol waste liquid is condensed by the first condenser 5 and then enters the light phase tank 7. Finally, it is fed into the reactor 9 through the reactor feed pump 8.

[0038] The catalyst placed in the catalyst tank 10 is fed into the reactor 9 via the catalyst pump 11. Under the action of the catalyst, the 1,4-butanediol waste liquid in the reactor 9 is heated, and the 1,4-butanediol undergoes an intramolecular dehydration reaction to produce tetrahydrofuran and water. At the same time, the mixture of vaporized tetrahydrofuran, water, and a small amount of impurities enters the second condenser 13 through the reactor tower 12. After being condensed by the second condenser 13, it enters the first reflux tank 14. Part of this mixture is returned to the reactor tower 12 from the top through the first reflux pump 15, and the remaining part is sent to the reaction distillate tank 17 as the reaction distillate through the first tower top collection pump 16. The residual liquid in the reactor 9 after the reaction is sent to the first cooler 19 through the reactor collection pump 18. After being cooled by the first cooler 19, it enters the reactor residual liquid tank 20.

[0039] The reaction distillate in the reaction distillate tank 17 is fed into the neutralization tank 22 by the neutralization tank feed pump 21, and the alkali solution in the alkali solution tank 24 is fed into the neutralization tank 22 by the alkali solution pump 23. The reaction distillate is neutralized by the alkali solution in the neutralization tank 22, and then fed into the mixing tank 26 by the neutralization tank discharge pump 25.

[0040] The neutralized reaction distillate is mixed with the permeate from the permeate pump 44 in the mixing tank 26. After mixing, it is sent to the azeotropic distillation column 28 for atmospheric distillation through the azeotropic column feed pump 27. Under the action of the azeotropic distillation column 28, the gas phase mixture of water containing a small amount of impurities and tetrahydrofuran azeotropically enters the third condenser 29 for condensation. After condensation, it enters the second reflux tank 30. Part of it is sent to the top of the azeotropic distillation column 28 and returned to the column through the second reflux pump 31. The remaining part is sent to the azeotropic liquid tank 33 through the second column top pump 32. At the same time, part of the liquid phase mixture of water and a small amount of impurities at the bottom of the azeotropic distillation column 28 is vaporized by the first reboiler 34 and returned to the column from the bottom of the azeotropic distillation column 28. The remaining part is sent to the second cooler 36 for cooling through the first column bottom pump 35. After cooling, it is sent to the wastewater tank 37 as wastewater.

[0041] The azeotropic liquid in the azeotropic liquid tank 33 is first heated by the heater 39 via the membrane module feed pump 38, and then enters the membrane module 40 for dehydration. The second vacuum pump 42 provides negative pressure for the membrane permeation of the membrane module 40, creating a pressure difference between the membrane feed side and the membrane permeation side. Driven by the pressure difference, water containing a small amount of tetrahydrofuran permeates through the membrane, and most of the water in the azeotropic liquid is removed. The water that permeates through the membrane is condensed by the fourth condenser 41, and the resulting permeate enters the permeate tank 43, and is then returned to the mixing tank 26 by the permeate pump 44. At the same time, the dehydrated azeotrope is cooled by the third cooler 45 and enters the dehydration tank 46 as the dehydration liquid.

[0042] The dehydrated liquid in the dehydrated liquid tank 46 is fed into the light-light distillation column 48 by the light-light distillation column feed pump 47 for pressurized distillation. Under the action of the light-light distillation column 48, the gaseous mixture containing a small amount of water and tetrahydrofuran enters the fifth condenser 49 for condensation. After condensation, it enters the third reflux tank 50. Part of it is sent back to the top of the light-light distillation column 48 by the third reflux pump 51, and the remainder is sent to the light impurity tank 53 by the third column top pump 52. At the same time, part of the liquid mixture of tetrahydrofuran and a small amount of heavy impurities at the bottom of the light-light distillation column 48 is vaporized by the second reboiler 54 and returned to the column from the bottom of the light-light distillation column 48. The remainder is sent to the fourth cooler 56 for cooling by the second column bottom pump 55, and then sent to the light-light liquid tank 57.

[0043] The light-removed liquid in the light-removed liquid tank 57 is fed into the product distillation column 59 for atmospheric distillation via the product column feed pump 58. Under the action of the product distillation column 59, the tetrahydrofuran gaseous mixture enters the sixth condenser 60 for condensation, and after condensation, it enters the fourth reflux tank 61. Part of it is sent back to the top of the product distillation column 59 by the fourth reflux pump 62, and the remainder is sent to the product tank 64 as the tetrahydrofuran product through the fourth column top pump 63. At the same time, part of the liquid mixture of heavy impurities and a small amount of tetrahydrofuran at the bottom of the product distillation column 59 is vaporized by the third reboiler 65 and returned to the column from the bottom of the product distillation column 59. The remainder is sent to the fifth cooler 67 for cooling by the third column bottom pump 66, and after cooling, it is sent to the heavy impurities tank 68.

[0044] This invention utilizes a combination of a reaction vessel and a distillation column to continuously convert 1,4-butanediol in waste liquid into high-value-added tetrahydrofuran under acidic conditions. The process is simple and has a high conversion rate. This invention adjusts the pH of the reaction distillate by adding alkali, controlling trace amounts of acid and aldehydes in the distillate. This not only achieves partial impurity removal but also effectively eliminates the damage of acidic substances to the membranes in subsequent membrane modules, greatly improving membrane lifespan. This invention couples membrane separation and distillation processes for the purification of tetrahydrofuran after the reaction, breaking the limitation of azeotropic reaction between tetrahydrofuran and water. Compared to traditional special distillation processes, energy consumption is also significantly reduced.

[0045] Here, the specific models of the devices mentioned above are not limited or described in detail, and the in-depth connection methods of the devices mentioned above are not described in detail, as they are common knowledge and can be understood by those skilled in the art.

[0046] This utility model embodiment is merely an illustration of its specific implementation and is not intended to limit its scope of protection. Those skilled in the art can make certain modifications based on this embodiment; therefore, all equivalent changes or modifications made in accordance with the scope of this utility model patent claim fall within the scope of this utility model patent claim.

Claims

1. A system for preparing high-purity tetrahydrofuran from 1,4-butanediol waste liquid, characterized in that, It includes a heavy phase separation device, a reaction device, a neutralization device, an azeotropic distillation device, a dehydration device, a light component removal distillation device, and a finished product distillation device, which are connected in sequence.

2. The system for preparing high-purity tetrahydrofuran from 1,4-butanediol waste liquid according to claim 1, characterized in that, The heavy phase separation device includes a raw material tank, a raw material pump, a scraped film evaporator, a heavy phase tank, a first condenser, a first vacuum pump, and a light phase tank. The raw material tank is connected to the scraped film evaporator via the raw material pump. The bottom of the scraped film evaporator is connected to the heavy phase tank, and the top of the scraped film evaporator is connected to the first condenser. The first condenser is connected to both the first vacuum pump and the light phase tank. The light phase tank is connected to the reaction device.

3. The system for preparing high-purity tetrahydrofuran from 1,4-butanediol waste liquid according to claim 2, characterized in that, The reaction apparatus includes a reactor feed pump, a reactor, a catalyst tank, a catalyst pump, a reactor tower, a second condenser, a first reflux tank, a first reflux pump, a first tower top pump, a reaction distillate tank, a reactor pump, a first cooler, and a reactor residue tank. The light phase tank is connected to the reactor via the reactor feed pump. The catalyst tank is connected to the reactor via the catalyst pump. The top of the reactor is connected to the reactor tower, and the bottom of the reactor tower is also connected to the reactor. The top of the reactor tower is connected to the second condenser, and the second condenser is connected to the first reflux tank. The first reflux tank is connected to both the first reflux pump and the first tower top pump. The first reflux pump is connected to the reactor tower. The first tower top pump is connected to the reaction distillate. The bottom of the reactor is connected to the first cooler via the reactor pump. The first cooler is connected to the reactor residue tank, and the reaction distillate tank is connected to the neutralization device.

4. The system for preparing high-purity tetrahydrofuran from 1,4-butanediol waste liquid according to claim 3, characterized in that, The neutralization apparatus includes a neutralization kettle feed pump, a neutralization kettle, an alkali pump, an alkali tank, a neutralization kettle discharge pump, and a mixing tank; the reaction distillate tank is connected to the neutralization kettle via the neutralization kettle feed pump, the alkali tank is connected to the neutralization kettle via the alkali pump, the bottom of the neutralization kettle is connected to the mixing tank via the neutralization kettle discharge pump, and the mixing tank is connected to the azeotropic distillation apparatus.

5. The system for preparing high-purity tetrahydrofuran from 1,4-butanediol waste liquid according to claim 4, characterized in that, The azeotropic distillation apparatus includes an azeotropic column feed pump, an azeotropic distillation column, a third condenser, a second reflux tank, a second reflux pump, a second top-of-column pump, an azeotropic liquid tank, a first reboiler, a first bottom-of-column pump, a second cooler, and a wastewater tank. The mixing tank is connected to the azeotropic distillation column via the azeotropic column feed pump. The top of the azeotropic distillation column is connected to the third condenser. The third condenser is connected to the second reflux tank. The second reflux tank is connected to both the second reflux pump and the second top-of-column pump. The second reflux pump is connected to the azeotropic distillation column. The second top-of-column pump is connected to the azeotropic liquid tank. One end of the first reboiler is connected to the lower part of the azeotropic distillation column, and the other end is connected to both the bottom pipe of the azeotropic distillation column and the first bottom-of-column pump. The first bottom-of-column pump is connected to the second cooler. The second cooler is connected to the wastewater tank. The azeotropic liquid tank is connected to the dehydration device.

6. The system for preparing high-purity tetrahydrofuran from 1,4-butanediol waste liquid according to claim 5, characterized in that, The dehydration device includes a membrane module feed pump, a heater, a membrane module, a fourth condenser, a second vacuum pump, a permeate tank, a permeate pump, a third cooler, and a dehydration tank. The azeotropic tank is connected to the heater via the membrane module feed pump. The heater is connected to the membrane module. One end of the membrane module is connected to the fourth condenser. The fourth condenser is connected to both the second vacuum pump and the permeate tank. The permeate tank is connected to the mixing tank via the permeate pump. The other end of the membrane module is connected to the third cooler. The third cooler is connected to the dehydration tank. The dehydration tank is connected to the light distillation unit.

7. The system for preparing high-purity tetrahydrofuran from 1,4-butanediol waste liquid according to claim 6, characterized in that, The light-weight distillation unit includes a light-weight distillation column feed pump, a light-weight distillation column, a fifth condenser, a third reflux tank, a third reflux pump, a third column top discharge pump, a light-weight waste tank, a second reboiler, a second column bottom discharge pump, a fourth cooler, and a light-weight liquid tank. The dehydrated liquid tank is connected to the light-weight distillation column via the light-weight distillation column feed pump. The top of the light-weight distillation column is connected to the fifth condenser. The fifth condenser is connected to the third reflux tank. The third reflux tank is connected to both the third reflux pump and the third column top discharge pump. The third reflux pump is connected to the light-weight distillation column. The third column top discharge pump is connected to the light-weight waste tank. One end of the second reboiler is connected to the lower part of the light-weight distillation column, and the other end is connected to both the bottom pipe of the light-weight distillation column and the second column bottom discharge pump. The second column bottom discharge pump is connected to the fourth cooler. The fourth cooler is connected to the light-weight liquid tank. The light-weight liquid tank is connected to the finished product distillation unit.

8. The system for preparing high-purity tetrahydrofuran from 1,4-butanediol waste liquid according to claim 7, characterized in that, The finished product distillation unit includes a finished product column feed pump, a finished product distillation column, a sixth condenser, a fourth reflux tank, a fourth reflux pump, a fourth column top-collection pump, a finished product tank, a third reboiler, a third column bottom-collection pump, a fifth cooler, and a heavy / mixed liquid tank. The light liquid removal tank is connected to the finished product distillation column via the finished product column feed pump. The finished product distillation column is connected to the sixth condenser. The sixth condenser is connected to the fourth reflux tank. The fourth reflux tank is connected to both the fourth reflux pump and the fourth column top-collection pump. The fourth reflux pump is connected to the finished product distillation column. The fourth column top-collection pump is connected to the finished product tank. One end of the third reboiler is connected to the lower part of the finished product distillation column, and the other end is connected to both the bottom pipe of the finished product distillation column and the third column bottom-collection pump. The third column bottom-collection pump is connected to the fifth cooler, and the fifth cooler is connected to the heavy / mixed liquid tank.

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