Refining device for separating multi-element heterogeneous azeotrope

Abstract

The utility model belongs to the field of rectification, and particularly discloses a refining device for separating multi-element heterogeneous azeotrope, the refining device comprises a first rectifying tower, a second rectifying tower, a third rectifying tower and a membrane separation assembly, the inlet of the first rectifying tower is used for introducing water and to-be-separated azeotrope, the tower top of the first rectifying tower is connected with the second rectifying tower, and the tower top of the third rectifying tower is connected with the membrane separation assembly; the tower kettle is connected with a third rectifying tower; the tower top of the second rectifying tower is connected with the first rectifying tower, and a tower kettle is used for extracting crude oil phase substances; the tower top of the third rectifying tower is connected with the membrane separation assembly, and the third rectifying tower is used for separating the roughly-refined water-phase substances to obtain alcohol substances and penetrating fluid. According to the method, a third component does not need to be added, complex rectification processes such as extractive rectification and azeotropic rectification are omitted, pollution to a system caused by addition of the third component is avoided, the product quality is improved while the cost is reduced, the alcohol substances with extremely high purity can be obtained, and the method has the advantages of being easy to operate and high in product purity.

Description

Technical Field

[0001] This application belongs to the field of distillation, and more specifically, relates to a refining apparatus for separating multi-component heterogeneous azeotropes. Background Technology

[0002] Multi-component heterogeneous azeotropes refer to azeotropic systems that simultaneously contain two or more liquid phases. When such azeotropes boil at constant pressure, their vapor composition ratio is the same as that of the solution, exhibiting the same composition as the solution. This also means that they cannot be separated by conventional distillation or fractionation methods.

[0003] Existing technologies mainly separate and purify multi-component heterogeneous azeotropes through extractive distillation or azeotropic distillation. However, traditional distillation is an energy-intensive process, with solvent recovery accounting for a large portion of the energy consumption in the production unit. Therefore, reducing the energy consumption of the separation and purification process has become an important issue. Utility Model Content

[0004] To address the shortcomings of existing technologies, this application provides a refining apparatus for separating multi-component heterogeneous azeotropes, aiming to solve the problem of high energy consumption in existing distillation apparatuses.

[0005] This application provides a refining apparatus for separating multi-component heterogeneous azeotropes, specifically including a first distillation column, a second distillation column, a third distillation column, and a membrane separation component. The inlet of the first distillation column is used to introduce water and the azeotropes to be separated, and to obtain primary oil phase and primary aqueous phase substances through phase-mass separation. The top of the first distillation column is connected to the second distillation column for feeding the primary oil phase substances into the second distillation column, while the bottom of the first distillation column is connected to the third distillation column for feeding the primary aqueous phase substances into the third distillation column.

[0006] The second distillation column is used to dehydrate and deethanol the primary oil phase material to obtain crude oil phase material and recovered aqueous phase material. The top of the second distillation column is connected to the first distillation column to send the recovered aqueous phase material back to the first distillation column. At the same time, the bottom of the second distillation column is used to discharge the crude oil phase material.

[0007] The third distillation column is used to purify the primary aqueous phase material to obtain crude aqueous phase material and wastewater. The top of the third distillation column is connected to a membrane separation unit to feed the crude aqueous phase material into the membrane separation unit, which is used to separate the crude aqueous phase material to obtain alcohols and permeate.

[0008] Compared with the prior art, the above-described technical solutions conceived in this application utilize water to extract alcohols from the azeotrope to be separated in the first distillation column, thereby avoiding the addition of a third component and eliminating complex distillation processes such as extractive distillation and azeotropic distillation, effectively reducing distillation costs. Furthermore, by combining the distillation column with a membrane separation component, the purity of the obtained alcohols can be effectively improved.

[0009] As a further preferred embodiment, the refining apparatus further includes a fourth distillation column and a first oil phase collection tank and a second oil phase collection tank connected to the top and bottom of the fourth distillation column, respectively. The fourth distillation column is connected to the bottom of the second distillation column for separating the crude oil phase substances and sending oil phase substances with different boiling points to the first oil phase collection tank and the second oil phase collection tank for collection.

[0010] As a further preferred embodiment, the top of the second distillation column is connected to the second distillation column and the first distillation column respectively via a first condenser and a reflux ratio controller.

[0011] As a further preferred embodiment, the reboiler of the second distillation column is connected to both the first reboiler and the fourth distillation column, and the other end of the first reboiler is connected to the second distillation column.

[0012] As a further preferred embodiment, the refining apparatus further includes a wastewater tank, an alcohol collection tank, and a permeate collection tank. The top of the third distillation column is connected to both the third distillation column and the membrane separation assembly via a second condenser. The bottom of the third distillation column is connected to both the second reboiler and the wastewater tank, and the other end of the second reboiler is connected to the third distillation column. The alcohol collection tank is connected to the permeate side of the membrane separation assembly, and the permeate collection tank is connected to the permeate side of the membrane separation assembly.

[0013] As a further preferred embodiment, the refining apparatus further includes a first heat exchanger, the tube side of which is connected to the top of the third distillation column and the inlet of the membrane separation component, respectively, and the shell side of which is connected to the permeate side of the membrane separation component and the alcohol collection tank, respectively, so as to preheat the crude aqueous phase material using the heat of the alcohol.

[0014] As a further preferred embodiment, the refining apparatus further includes a second heat exchanger, the tube side of which is connected to the bottom of the first distillation column and the feed inlet of the third distillation column, respectively, and the shell side of which is connected to the bottom of the third distillation column and the wastewater tank, respectively, so as to use the heat of the wastewater to preheat the primary aqueous phase material.

[0015] As a further preferred embodiment, the top of the fourth distillation column is connected to both the fourth distillation column and the first oil phase collection tank via a third condenser, and the bottom of the fourth distillation column is connected to both the third reboiler and the second oil phase collection tank.

[0016] As a further preferred embodiment, the first, second, and third distillation columns are packed columns, the fourth distillation column is a plate column, the first, second, and third condensers are shell-and-tube heat exchangers, and the first, second, and third reboilers are thermosiphon reboilers.

[0017] As a further preferred embodiment, the membrane separation component uses an inorganic molecular sieve membrane.

[0018] In summary, compared with the prior art, the technical solutions conceived in this application have the following main technical advantages:

[0019] 1. The purification apparatus provided in this application does not require the addition of a third component during the solvent recovery process, eliminating complex distillation processes such as extractive distillation and azeotropic distillation, avoiding pollution to the system caused by the addition of a third component, reducing costs while improving product quality. At the same time, this application combines a distillation column with a membrane separation component, which can obtain alcohols with extremely high purity, and has the advantages of simple operation and high product purity.

[0020] 2. In particular, by setting up a fourth distillation column, this application can further separate crude oily substances according to their different boiling points, thereby achieving the separation and refining of oily substances, and has the advantages of good separation effect and high product purity;

[0021] 3. In addition, by setting up a first heat exchanger, this application can utilize the heat of alcohol substances to preheat the crude aqueous phase substances, and by setting up a second heat exchanger, it can utilize the heat of wastewater to preheat the primary aqueous phase substances, thereby fully realizing the recovery and utilization of waste heat and further reducing the energy consumption of the refining unit. Attached Figure Description

[0022] Figure 1 This is a schematic diagram of the results from the purification apparatus for separating multi-component heterogeneous azeotropes provided in the embodiments of this application.

[0023] In all the accompanying drawings, the same reference numerals are used to denote the same elements or structures, wherein:

[0024] 1-First distillation column, 2-Second distillation column, 3-First condenser, 4-First reboiler, 5-Fourth distillation column, 6-Third condenser, 7-Third reboiler, 8-Third distillation column, 9-Second condenser, 10-Second reboiler, 11-First heat exchanger, 12-Membrane separation assembly, 13-Reflux ratio controller, 14-First oil phase collection tank, 15-Second oil phase collection tank, 16-Alcohol collection tank, 17-Permeate collection tank, 18-Wastewater tank, 19-Second heat exchanger. Detailed Implementation

[0025] To make the objectives, technical solutions, and advantages of this application clearer, the following detailed description is provided in conjunction with the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are merely illustrative and not intended to limit the scope of this application.

[0026] like Figure 1 As shown, this application provides a refining apparatus for separating multi-component heterogeneous azeotropes, specifically including a first distillation column 1, a second distillation column 2, a third distillation column 8, and a membrane separation component 12. The inlet of the first distillation column 1 is used to introduce water and the azeotrope to be separated, and to obtain primary oil phase and primary aqueous phase through phase-mass separation. Water enters from the top of the first distillation column 1, and the azeotrope to be separated enters from the bottom of the first distillation column 1. Mass transfer separation of the aqueous phase and oil phase is achieved in the first distillation column 1. Water can extract alcohols from the azeotrope to be separated to obtain primary aqueous phase. The top of the first distillation column 1 is connected to the second distillation column 2 for feeding the primary oil phase into the second distillation column 2. At the same time, the bottom of the first distillation column 1 is connected to the third distillation column 8 for feeding the primary aqueous phase into the third distillation column 8.

[0027] The second distillation column 2 is used to dehydrate and deethanol the primary oil phase material to obtain crude oil phase material and recover aqueous phase material. The top of the second distillation column 2 is connected to the first distillation column 1 to recover aqueous phase material and send it back to the first distillation column 1. At the same time, the bottom of the second distillation column 2 is used to discharge the crude oil phase material for collection.

[0028] The third distillation column 8 is used to purify the primary aqueous phase material to obtain crude aqueous phase material and wastewater. The top of the third distillation column is connected to the membrane separation component 12, which is used to feed the crude aqueous phase material into the membrane separation component 12. The membrane separation component 12 is used to separate the crude aqueous phase material to obtain alcohols and permeate (water).

[0029] The refining apparatus provided in this application uses water to extract alcohols from the azeotrope to be separated in the first distillation column, which avoids the addition of a third component and eliminates complex distillation processes such as extractive distillation and azeotropic distillation, effectively reducing distillation costs. Furthermore, this application combines the distillation column with a membrane separation component, which can directly obtain refined alcohols, and has the advantages of simple operation and high product purity.

[0030] Furthermore, if it is necessary to further purify the crude oil phase material discharged from the second distillation column 2, the refining device may also include a fourth distillation column 5 and a first oil phase collection tank 14 and a second oil phase collection tank 15 connected to the top and bottom of the fourth distillation column 5, respectively. The fourth distillation column 5 is connected to the bottom of the second distillation column 2 and is used to separate the crude oil phase material, and send oil phase materials with different boiling points to the first oil phase collection tank 14 and the second oil phase collection tank 15 for collection, thereby realizing the separation and purification of the crude oil phase material.

[0031] Furthermore, the top of the second distillation column 2 is connected to both the second distillation column 2 and the first distillation column 1 via the first condenser 3 and the reflux ratio controller 13, respectively. This allows the vapor discharged from the top of the second distillation column 2 to be condensed to obtain recovered aqueous phase material. A portion of the recovered aqueous phase material is sent back to the second distillation column 2 for reflux, while the other portion is sent back to the first distillation column 1 for recovery. This recovered aqueous phase material is a mixture of water and alcohol. The reflux ratio controller 13 is used to regulate the proportion of reflux to the second distillation column 2, thereby controlling the column top temperature. The bottom of the second distillation column 2 is connected to both the first reboiler 4 and the fourth distillation column 5, with the other end of the first reboiler 4 connected to the second distillation column 2. This allows a portion of the crude oil phase material to be sent to the fourth distillation column 5 for refining, while the other portion is sent back to the second distillation column 2 for reflux.

[0032] Furthermore, the refining device also includes a wastewater tank 18, an alcohol collection tank 16, and a permeate collection tank 17. The third distillation column 8 can purify the fed primary aqueous phase material to obtain crude aqueous phase material and wastewater, wherein the crude aqueous phase material is a mixture of water and alcohol. The top of the third distillation column 8 is connected to the third distillation column 8 and the membrane separation unit 12 respectively through the second condenser 9, thereby condensing the steam discharged from the third distillation column 8 to obtain crude aqueous phase material, and sending a portion of the crude aqueous phase material back to the third distillation column 8 for reflux, and sending another portion of the crude aqueous phase material to the membrane separation unit 12 for separation of alcohol and water. The alcohol collection tank 16 is connected to the permeate side of the membrane separation unit 12 for collecting the refined alcohol material, and the permeate collection tank 17 is connected to the permeate side of the membrane separation unit 12 for collecting permeate (water). The bottom of the third distillation column 8 is connected to the second reboiler 10 and the wastewater tank 18, respectively. The other end of the second reboiler 10 is connected to the third distillation column 8, so that a portion of the wastewater is vaporized and sent back to the third distillation column 8, while the other portion of the wastewater is sent to the wastewater tank 18 for collection.

[0033] Furthermore, the refining apparatus also includes a first heat exchanger 11. The tube side of the first heat exchanger 11 is connected to the top of the third distillation column 8 and the inlet of the membrane separation component 12, respectively. The shell side of the first heat exchanger 11 is connected to the permeate side of the membrane separation component 12 and the alcohol collection tank 16, respectively. Thus, the alcohol separated by the membrane separation component 12 is used as a heat source to preheat the crude aqueous phase material discharged from the top of the third distillation column 8. Then, the heat-exchanged alcohol is sent to the alcohol collection tank 16 for collection, thereby realizing the recovery and utilization of the waste heat of the alcohol and reducing the energy consumption of the alcohol solvent recovery process.

[0034] Furthermore, the refining apparatus also includes a second heat exchanger 19. The tube side of the second heat exchanger 19 is connected to the bottom of the first distillation column 1 and the feed inlet of the third distillation column 8, respectively. The shell side of the second heat exchanger 19 is connected to the bottom of the third distillation column 8 and the wastewater tank 18, respectively. Thus, the wastewater discharged from the third distillation column 8 is used as a heat source to preheat the primary aqueous phase material discharged from the bottom of the first distillation column 1. Then, the wastewater after heat exchange is sent to the wastewater tank 18 for collection, thereby realizing the recovery and utilization of wastewater heat and reducing the energy consumption of the alcohol solvent recovery process.

[0035] Furthermore, the top of the fourth distillation column 5 is connected to both the fourth distillation column 5 and the first oil phase collection tank 14 via the third condenser 6, thereby condensing the vapor discharged from the top of the fourth distillation column 5 to obtain the first oil phase substance. A portion of the first oil phase substance is returned to the fourth distillation column 5 for reflux, and the other portion is sent to the first oil phase collection tank 14 for collection. The bottom of the fourth distillation column 5 is connected to the third reboiler 7 and the second oil phase collection tank 15, respectively, and a portion of the second oil phase substance is vaporized and returned to the fourth distillation column 5, while the other portion is sent to the second oil phase collection tank 15 for collection.

[0036] Furthermore, the first distillation column 1, the second distillation column 2, and the third distillation column 8 are packed columns, while the fourth distillation column 5 is a plate column. The first condenser 3, the second condenser 9, and the third condenser 6 are shell-and-tube heat exchangers, and the first reboiler 4, the second reboiler 10, and the third reboiler 7 are thermosiphon reboilers. The vapor permeation membrane of the membrane separation assembly 12 is an inorganic molecular sieve membrane.

[0037] In a preferred embodiment of this application, the azeotrope to be separated is a mixture of ethanol, heptane, toluene, and water. The feed liquid (a mixture of ethanol, heptane, toluene, and water, comprising 69 wt% ethanol, 26.4 wt% n-heptane, 2.1 wt% toluene, and 2.5 wt% water by mass fraction) is first separated into aqueous and oil phases in a first distillation column 1. The oil phase overflowing from the top of the first distillation column 1 enters a second distillation column 2. The ethanol-water solution removed from the top of the second distillation column 2 is returned to the first distillation column 1. The heptane and toluene solution from the bottom of the column enters a fourth distillation column 5 for purification. The heptane obtained from the top of the fourth distillation column 5 is collected in a first oil phase collection tank 14. The toluene obtained from the bottom of the column is cooled and collected in a second oil phase collection tank 15. The aqueous phase from the bottom of the first distillation column 1 is passed through a third distillation column 8 to obtain crude ethanol. The crude ethanol is vaporized and purified by a membrane separation unit 12 to obtain ethanol product. The bottom of the column is discharged as wastewater to a wastewater tank 18.

[0038] The temperature of the first distillation column 1 is 25℃~26℃, the top pressure is 2 kPa~10 kPa, and the bottom pressure is 160 kPa~170 kPa; the top temperature of the second distillation column 2 is 81℃, the bottom temperature is 100℃, the top pressure is 3 kPa~10 kPa, and the bottom pressure is 10 kPa~15 kPa; the top temperature of the fourth distillation column 5 is 98℃~99℃, the bottom temperature is 102℃, the top pressure is 3 kPa~10 kPa, and the bottom pressure is 22 kPa~29 kPa; the top temperature of the third distillation column 8 is 78℃~80℃, the bottom temperature is 100℃, the top pressure is 3 kPa~10 kPa, and the bottom pressure is 4.5 kPa~10 kPa. The reflux temperature of the second distillation column 2, the fourth distillation column 5, and the third distillation column 8 is 60℃. The molar reflux ratio of the second distillation column 2 is 0.3, the molar reflux ratio of the fourth distillation column 5 is 2.5, and the molar reflux ratio of the third distillation column 8 is 0.9. The effluent side pressure of the membrane separation unit 12 is 130 kPa~150 kPa, and the temperature is 100℃~108℃. The heptane mass fraction after separation in the fourth distillation column 5 is greater than 95%, and it does not contain ethanol or water. The ethanol mass fraction after separation in the third distillation column 8 is greater than 85%. After purification by the membrane separation unit 12, an ethanol product with a purity of over 99.5% is obtained.

[0039] In the description of this application, it should be understood that the terms "first" and "second" are used for descriptive purposes only and should not be construed as indicating or implying relative importance or implicitly specifying the number of technical features indicated. Therefore, a feature defined as "first" or "second" may explicitly or implicitly include one or more of that feature. In the description of this application, "multiple" means two or more, unless otherwise explicitly specified.

[0040] Those skilled in the art will readily understand that the above description is merely a preferred embodiment of this application and is not intended to limit this application. Any modifications, equivalent substitutions, and improvements made within the spirit and principles of this application should be included within the protection scope of this application.

Claims

1. A refining apparatus for separating multi-component heterogeneous azeotropes, characterized in that, The refining apparatus includes a first distillation column (1), a second distillation column (2), a third distillation column (8), and a membrane separation assembly (12). The inlet of the first distillation column (1) is used to introduce water and the azeotrope to be separated and obtain primary oil phase and primary aqueous phase through phase separation. The top of the first distillation column (1) is connected to the second distillation column (2) to feed the primary oil phase into the second distillation column (2). At the same time, the bottom of the first distillation column (1) is connected to the third distillation column (8) to feed the primary aqueous phase into the third distillation column (8). The second distillation column (2) is used to dehydrate and deethanol the primary oil phase material to obtain crude oil phase material and recovered aqueous phase material. The top of the second distillation column (2) is connected to the first distillation column (1) to send the recovered aqueous phase material back to the first distillation column (1). At the same time, the bottom of the second distillation column (2) is used to discharge the crude oil phase material. The third distillation column (8) is used to purify the primary aqueous phase material to obtain crude aqueous phase material and wastewater. The top of the third distillation column (8) is connected to the membrane separation component (12) to send the crude aqueous phase material into the membrane separation component (12). The membrane separation component (12) is used to separate the crude aqueous phase material to obtain alcohol and permeate.

2. The refining apparatus as described in claim 1, characterized in that, The refining apparatus also includes a fourth distillation column (5) and a first oil phase collection tank (14) and a second oil phase collection tank (15) connected to the top and bottom of the fourth distillation column (5), respectively. The fourth distillation column (5) is connected to the bottom of the second distillation column (2) for separating the crude oil phase substances and sending oil phase substances with different boiling points into the first oil phase collection tank (14) and the second oil phase collection tank (15) for collection.

3. The refining apparatus as described in claim 1, characterized in that, The top of the second distillation column (2) is connected to the second distillation column (2) and the first distillation column (1) through the first condenser (3) and the reflux ratio controller (13), respectively.

4. The refining apparatus as described in claim 3, characterized in that, The bottom of the second distillation column (2) is connected to the feed inlets of the first reboiler (4) and the fourth distillation column (5), respectively, and the other end of the first reboiler (4) is connected to the second distillation column (2).

5. The refining apparatus as described in claim 4, characterized in that, The refining apparatus also includes a wastewater tank (18), an alcohol collection tank (16), and a permeate collection tank (17). The top of the third distillation column (8) is connected to the third distillation column (8) and the membrane separation unit (12) respectively via a second condenser (9). The bottom of the third distillation column (8) is connected to the second reboiler (10) and the wastewater tank (18) respectively. The other end of the second reboiler (10) is connected to the third distillation column (8). The alcohol collection tank (16) is connected to the permeate side of the membrane separation unit (12). The permeate collection tank (17) is connected to the permeate side of the membrane separation unit (12).

6. The refining apparatus as described in claim 5, characterized in that, The refining apparatus also includes a first heat exchanger (11), the tube side of which is connected to the top of the third distillation column (8) and the inlet of the membrane separation unit (12), and the shell side of which is connected to the osmosis side of the membrane separation unit (12) and the alcohol collection tank (16), so as to use the heat of the alcohol to preheat the crude aqueous phase material.

7. The refining apparatus as described in claim 5, characterized in that, The refining apparatus also includes a second heat exchanger (19), the tube side of which is connected to the bottom of the first distillation column (1) and the feed inlet of the third distillation column (8), and the shell side of which is connected to the bottom of the third distillation column (8) and the wastewater tank (18), so as to use the heat of the wastewater to preheat the primary aqueous phase material.

8. The refining apparatus as described in claim 5, characterized in that, The top of the fourth distillation column (5) is connected to the fourth distillation column (5) and the first oil phase collection tank (14) respectively through the third condenser (6), and the bottom of the fourth distillation column (5) is connected to the third reboiler (7) and the second oil phase collection tank (15) respectively.

9. The refining apparatus as described in claim 8, characterized in that, The first distillation column (1), the second distillation column (2) and the third distillation column (8) are packed columns, the fourth distillation column (5) is a plate column, the first condenser (3), the second condenser (9) and the third condenser (6) are shell and tube heat exchangers, and the first reboiler (4), the second reboiler (10) and the third reboiler (7) are thermosiphon reboilers.

10. The refining apparatus according to any one of claims 1 to 9, characterized in that, The membrane separation component (12) uses an inorganic molecular sieve membrane.

Images