Extracting and rectifying device

Abstract

The invention provides an extraction and rectification device, and belongs to the technical field of rectification equipment, the extraction and rectification device comprises an extraction and rectification tower and an extraction agent recovery tower, a tower bottom discharge port of the extraction agent recovery tower is connected with a reboiler, the reboiler is connected with the extraction and rectification tower through a diversion tank, and the diversion tank is connected with the extraction and rectification tower. Two heat conducting partition plates are fixedly connected to the interior of the flow dividing tank, and the two heat conducting partition plates can divide the interior of the flow dividing tank into a flow guide cavity, a buffering cavity and a heating cavity in sequence from bottom to top; through the arrangement of the shunting tank, on one hand, direct heating of a tower bottom product entering the heating cavity is avoided, on the other hand, a product entering the buffer cavity can be heated, and the phenomenon that a tower top product becomes liquid due to heat loss in the transportation process is avoided; according to the technical scheme, the extractive distillation tower can be heated through products entering the buffer cavity, and then the two towers can be heated through one reboiler, so that the energy loss is reduced, and the cost is reduced.

Description

Technical Field

[0001] The invention belongs to the technical field of distillation equipment, and in particular relates to an extractive distillation device. Background Art

[0002] Extractive distillation, also known as extractive distillation, is a technology that uses selective solvents to separate the volatility of components in a mixture. Its principle is to introduce a third component into the raw liquid and adjust the relative volatility between the components to achieve effective separation.

[0003] The Chinese patent with application number CN202411769747.3 discloses a method for extractive distillation separation of 1-fluoro-1,1-dichloroethane and 1,1,1,3,3-pentafluorobutane azeotrope. The method for extractive distillation separation of 1-fluoro-1,1-dichloroethane and 1,1,1,3,3-pentafluorobutane azeotrope, adds an extractant to the azeotrope of 1-fluoro-1,1-dichloroethane and 1,1,1,3,3-pentafluorobutane, and the extractant is one or more of n-pentanol and n-heptanol. The invention adopts intermittent extractive distillation or continuous extractive distillation operation, and has the advantages of simple and efficient separation process, high product purity, low loss rate of extractant, and recyclable extractant, which can avoid causing environmental pollution.

[0004] However, in the continuous extractive distillation process, an extractive distillation tower and an extractant recovery tower need to be used in combination. Usually, two reboilers need to be connected to meet the extraction requirements. The use of two reboilers consumes a lot of energy and is costly. In addition, when the extractive distillation tower uses the extractant to separate the azeotropic mixture of HCFC-141b (dichlorofluoroethane) and HFC-365mfc (1,1,1,3,3-pentafluorobutane), it may be affected by factors such as leakage or insufficient gas-liquid two-phase mass transfer, resulting in the bottom product of the extractive distillation tower being doped with some HCFC-141b, resulting in the mixed substance entering the extractant recovery tower. When separating HFC-365mfc and the extractant, HCFC-141b exists, affecting the separation quality.

[0005] Therefore, in order to solve the above problems, it is necessary to provide an extractive distillation device. Summary of the invention

[0006] The object of the present invention is to provide an extractive distillation device, which aims to solve the problem that the extractive distillation in the prior art requires the use of multiple towers such as an extractive distillation tower and an extractant recovery tower, and usually requires the connection of multiple reboilers to meet the extraction requirements. The use of multiple reboilers has high energy consumption and high cost. In addition, when the extractive distillation tower separates azeotropic products of HCFC-141b and HFC-365mfc by using an extractant, it may be affected by factors such as liquid leakage or insufficient gas-liquid two-phase mass transfer, resulting in the bottom product of the extractive distillation tower being doped with part of HCFC-141b, resulting in the mixed substance entering the extractant recovery tower, and HCFC-141b is present when separating HFC-365mfc and the extractant, which affects the separation quality.

[0007] To achieve the above object, the present invention provides the following technical solutions: An extractive distillation device comprises an extractive distillation tower and an extractant recovery tower: The bottom discharge port of the extractant recovery tower is connected to a reboiler, and the reboiler is connected to the extractive distillation tower through a split tank, and the bottom product and the top product of the extractant recovery tower can both enter the split tank, wherein the bottom product of the extractant recovery tower can heat the top product of the extractant recovery tower in the split tank after being heated by the reboiler, and the top product of the extractant recovery tower in the split tank can enter the extractive distillation tower, and can heat the substances in the extractive distillation tower; Two heat-conducting baffles are fixedly connected to the interior of the diverter tank, and the two heat-conducting baffles can divide the interior of the diverter tank into a diversion chamber, a buffer chamber and a heating chamber from bottom to top. A first feed pipe connected to the diversion chamber is provided at the bottom of the diverter tank, a first discharge pipe connected to the diversion chamber is provided at the outside of the diverter tank, a second discharge pipe connected to the buffer chamber is provided at the top of the diverter tank, a second feed pipe connected to the buffer chamber is provided at the outside of the diverter tank, a third feed pipe and a third discharge pipe connected to the heating chamber are also provided at the outside of the diverter tank, and at least two diverter pipes connected to the second discharge pipe and the heating chamber are provided at the top of the diverter tank.

[0008] Preferably, the discharge port of the reboiler is connected to a first reflux tank, and is communicated with a first feed pipe, the first discharge pipe is communicated with a bottom reflux port of the extractant recovery tower, the bottom product of the extractant recovery tower can enter the interior of the reboiler, and after heating, part of the product entering the reboiler enters the interior of the guide cavity through the first feed pipe, and the other part enters the interior of the first reflux tank, the first reflux tank is connected to the extractant feed port of the extractive distillation tower through a reflux pump, the product entering the first reflux tank can enter the interior of the extractive distillation tower through the reflux pump, and the product entering the interior of the guide cavity can enter the interior of the extractant recovery tower through the first discharge pipe.

[0009] Preferably, the bottom discharge port of the extractive distillation tower is connected to the third feed pipe, and the third discharge pipe is connected to the feed port of the extractant recovery tower. The bottom product of the extractive distillation tower can enter the interior of the heating chamber through the third feed pipe, and the product entering the interior of the heating chamber can enter the interior of the extractant recovery tower through the third discharge pipe.

[0010] Preferably, the top of the extractant recovery tower is connected to the second feed pipe, and the second discharge pipe is connected to the bottom reflux port of the extractive distillation tower through the first condenser. The top product of the extractant recovery tower can enter the interior of the buffer chamber through the second feed pipe, and the product entering the buffer chamber can enter the interior of the extractive distillation tower through the second discharge pipe and the first condenser.

[0011] Preferably, the connection position of the second feed pipe and the extractant recovery tower is higher than the connection position of the third discharge pipe and the extractant recovery tower, each of the guide pipes is inclined, the connection position of the guide pipe and the second discharge pipe is higher than the connection position of the guide pipe and the heating chamber, and the connection positions of the third feed pipe and the third discharge pipe and the heating chamber are both lower than the connection position of the guide pipe and the heating chamber.

[0012] Preferably, the top discharge port of the extractive distillation tower is connected to a second condenser, the discharge port of the second condenser is connected to a second reflux tank, the discharge port of the second reflux tank is connected to a first collecting tank, and is communicated with the top reflux port of the extractive distillation tower.

[0013] Preferably, the top product of the extractive distillation tower can enter the interior of the second reflux tank after being condensed by the second condenser, part of the product entering the interior of the second reflux tank can enter the interior of the first collecting tank, and the other part can enter the interior of the extractive distillation tower.

[0014] Preferably, the top discharge port of the extractant recovery tower is connected to a third condenser, the discharge port of the third condenser is connected to a third reflux tank, the discharge port of the third reflux tank is connected to a second collecting tank, and is communicated with the top reflux port of the extractant recovery tower.

[0015] Preferably, part of the top product of the extractant recovery tower can enter the second feed pipe, and another part can enter the third reflux tank after condensation through the third condenser, part of the product entering the third reflux tank can enter the second collecting tank, and another part can enter the extractant recovery tower.

[0016] Compared with the prior art, the present invention has the following beneficial effects: 1. The present invention adopts the arrangement of the splitter tank. After the reboiler heats the extractant of the bottom product of the extractant recovery tower, a part of the extractant can enter the interior of the guide chamber through the first feed pipe. The extractant inside the guide chamber will first heat the material inside the buffer chamber through the heat-conducting partition. Then, the material inside the buffer chamber will heat the bottom product of the extractive distillation tower entering the heating chamber through another heat-conducting partition. The purpose is to avoid directly heating the bottom product of the extractive distillation tower entering the heating chamber, and prevent the n-pentanol and HFC-365mfc entering the heating chamber from being separated into more due to the high temperature. HFC-365mfc gas can avoid the influence of separation efficiency due to the low content of HFC-365mfc in the material entering the extractant recovery tower. On the other hand, the top product of the extractant recovery tower entering the buffer chamber can be heated to avoid the top product changing from gas to liquid due to heat loss during transportation, which is convenient for subsequent use. The product entering the buffer chamber can enter the interior of the extractive distillation tower through the second discharge pipe and the first condenser, and can heat the extractive distillation tower to ensure the reaction temperature inside the extractive distillation tower. The heating of the two towers can be realized through a reboiler, which reduces energy loss and reduces costs.

[0017] 2. In the present invention, by setting the draft pipe, part of the top product of the extractant recovery tower can enter the second feed pipe, and the bottom product entering the second feed pipe can enter the buffer chamber. Since the temperature inside the buffer chamber is higher than the temperature inside the heating chamber, the internal pressure of the buffer chamber is greater than the internal pressure of the heating chamber, resulting in the top material in the buffer chamber maintaining a gas phase entering the extractive distillation tower from the second discharge pipe at a larger flow rate, resulting in the pressure at the connection between the second discharge pipe and the draft pipe becoming weak. Moreover, since there is a certain temperature and pressure inside the heating chamber, the top material of the extractive distillation tower that is volatilized by heat when entering the heating chamber enters the second discharge pipe in a gaseous state through the draft pipe, and coexists with the top product of the extractant recovery tower, and re-enters the extractive distillation tower for separation. By the coexistence of the top product of the extractant recovery tower and the top material of the extractive distillation tower, the content of the top material of the extractive distillation tower in the material entering the extractant recovery tower can be reduced, and the separation quality of the extractant recovery tower can be improved. BRIEF DESCRIPTION OF THE DRAWINGS

[0018] The accompanying drawings are used to provide a further understanding of the present invention and constitute a part of the specification. Together with the embodiments of the present invention, they are used to explain the present invention and do not constitute a limitation of the present invention. In the accompanying drawings: Figure 1 It is a schematic diagram of the structure of the extractive distillation device of the present invention; Figure 2 It is a structural schematic diagram of the diversion tank of the present invention; Figure 3 It is a structural cross-sectional view of the diversion tank of the present invention.

[0019] In the figure: 1. extractive distillation tower; 11. first condenser; 12. second condenser; 13. second reflux tank; 14. first collecting tank; 2. extractant recovery tower; 21. reboiler; 22. first reflux tank; 23. reflux pump; 24. third condenser; 25. third reflux tank; 26. second collecting tank; 3. diversion tank; 31. heat-conducting baffle; 32. guide chamber; 33. buffer chamber; 34. heating chamber; 35. first feed pipe; 36. first discharge pipe; 37. second discharge pipe; 38. second feed pipe; 39. third feed pipe; 310. third discharge pipe; 311. guide pipe. DETAILED DESCRIPTION

[0020] The following will be combined with the drawings in the embodiments of the present invention to clearly and completely describe the technical solutions in the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention. Embodiment 1

[0021] Existing extractive distillation often requires the use of multiple towers such as extractive distillation towers and extractant recovery towers. Usually, multiple reboilers need to be connected to meet the extraction needs. The purpose of using multiple reboilers is to ensure the temperature requirements of different reaction towers. However, the overall energy consumption of multiple reboilers is high and the cost is relatively high.

[0022] See also Figures 1 to 3 The present invention provides the following technical solution: an extractive distillation device, comprising an extractive distillation tower 1 and an extractant recovery tower 2: The bottom discharge port of the extractant recovery tower 2 is connected to a reboiler 21, and the reboiler 21 is connected to the extractive distillation tower 1 through a split tank 3. Both the bottom product and the top product of the extractant recovery tower 2 can enter the split tank 3, wherein the bottom product of the extractant recovery tower 2 can heat the top product of the extractant recovery tower 2 inside the split tank 3 after being heated by the reboiler 21, and the top product of the extractant recovery tower 2 inside the split tank 3 can heat the extractant distillation tower 1 entering the extractive distillation tower 1.

[0023] Two heat-conducting baffles 31 are fixedly connected inside the diverter tank 3, and the two heat-conducting baffles 31 can divide the inside of the diverter tank 3 into a diversion chamber 32, a buffer chamber 33 and a heating chamber 34 from bottom to top. A first feed pipe 35 connected to the diversion chamber 32 is provided at the bottom of the diverter tank 3, a first discharge pipe 36 connected to the diversion chamber 32 is provided on the outside of the diverter tank 3, a second discharge pipe 37 connected to the buffer chamber 33 is provided on the top of the diverter tank 3, a second feed pipe 38 connected to the buffer chamber 33 is provided on the outside of the diverter tank 3, a third feed pipe 39 and a third discharge pipe 310 connected to the heating chamber 34 are also provided on the outside of the diverter tank 3, and at least two diverter pipes 311 connected to the second discharge pipe 37 and the heating chamber 34 are provided on the top of the diverter tank 3.

[0024] The bottom discharge port of the extractant recovery tower 2 is connected to the reboiler 21, and the discharge port of the reboiler 21 is connected to the first reflux tank 22. The discharge port of the reboiler 21 is connected to the first feed pipe 35, and the first discharge pipe 36 is connected to the bottom reflux port of the extractant recovery tower 2. The bottom product of the extractant recovery tower 2 can enter the interior of the reboiler 21. After heating, part of the product entering the interior of the reboiler 21 enters the interior of the guide cavity 32 through the first feed pipe 35, and the other part enters the interior of the first reflux tank 22. The first reflux tank 22 is connected to the extractant feed port of the extractive distillation tower 1 through the reflux pump 23. The product entering the first reflux tank 22 can enter the interior of the extractive distillation tower 1 through the reflux pump 23, and the product entering the interior of the guide cavity 32 can enter the interior of the extractive distillation tower 1 through the first discharge pipe 36.

[0025] The bottom discharge port of the extractive distillation tower 1 is connected to the third feed pipe 39, and the third discharge pipe 310 is connected to the feed port of the extractant recovery tower 2. The bottom product of the extractive distillation tower 1 can enter the interior of the heating chamber 34 through the third feed pipe 39, and the product entering the interior of the heating chamber 34 can enter the interior of the extractant recovery tower 2 through the third discharge pipe 310.

[0026] The top of the extractant recovery tower 2 is connected to the second feed pipe 38, and the second discharge pipe 37 is connected to the bottom reflux port of the extractive distillation tower 1 through the first condenser 11. The top product of the extractant recovery tower 2 can enter the interior of the buffer chamber 33 through the second feed pipe 38, and the product entering the interior of the buffer chamber 33 can enter the interior of the extractive distillation tower 1 through the second discharge pipe 37 and the first condenser 11.

[0027] The purpose of providing the first condenser 11 is to prevent the temperature of the product entering the extractive distillation tower 1 from the buffer chamber 33 from being higher than the internal reaction temperature of the extractive distillation tower 1 .

[0028] The top discharge port of the extractive distillation tower 1 is connected to a second condenser 12 , the discharge port of the second condenser 12 is connected to a second reflux tank 13 , the discharge port of the second reflux tank 13 is connected to a first collecting tank 14 , and the discharge port of the second reflux tank 13 is communicated with the top reflux port of the extractive distillation tower 1 .

[0029] The top product of the extractive distillation tower 1 can enter the second reflux tank 13 after condensation through the second condenser 12 , part of the product entering the second reflux tank 13 can enter the first collecting tank 14 , and the other part can enter the extractive distillation tower 1 .

[0030] Usually, the top product of the extractive distillation tower 1 is a gas, which is condensed into a liquid by the second condenser 12 and enters the second reflux tank 13. A part of it enters the first collecting tank 14 for collection, and the other part refluxes to the extractive distillation tower 1 to ensure the liquid level height inside the extractive distillation tower 1 and maintain the pressure inside the tower.

[0031] The top discharge port of the extractant recovery tower 2 is connected to the third condenser 24, the discharge port of the third condenser 24 is connected to the third reflux tank 25, the discharge port of the third reflux tank 25 is connected to the second collecting tank 26, and the discharge port of the third reflux tank 25 is connected to the top reflux port of the extractant recovery tower 2.

[0032] Part of the top product of the extractant recovery tower 2 can enter the second feed pipe 38, and another part can enter the third reflux tank 25 after condensation through the third condenser 24. Part of the product entering the third reflux tank 25 can enter the second collecting tank 26, and another part can enter the extractant recovery tower 2.

[0033] Usually, the top product of the extractant recovery tower 2 is gas. After being condensed into liquid by the third condenser 24, part of it enters the second collecting tank 26 for collection, and the other part flows back to the extractant recovery tower 2 to ensure the liquid level height inside the extractant recovery tower 2 and maintain the pressure inside the tower.

[0034] The raw material is added through the feed port of the extractive distillation tower 1, and the extractant is added through the extractant feed port of the extractive distillation tower 1, which is the prior art and will not be described in detail.

[0035] For example, when separating the azeotrope of HCFC-141b and HFC-365mfc, by selecting n-pentanol as the extractant, during the process of separating the azeotrope of HCFC-141b and HFC-365mfc by n-pentanol in the extractive distillation tower 1, the product at the bottom of the extractive distillation tower 1 is mainly a mixture of n-pentanol and HFC-365mfc, and the product at the top of the extractive distillation tower 1 is mainly HCFC-141b, wherein the boiling point of HFC-365mfc is about 40°C, the boiling point of HCFC-141b is about 32°C, and the boiling point of the extractant n-pentanol is about 138°C. Since n-pentanol has a strong reaction with HFC-365mfc, during separation, n-pentanol can By mixing n-pentanol with HFC-365mfc, the boiling point is increased and the volatility of HFC-365mfc is reduced, so that HCFC-141b can be separated. The mixture of n-pentanol and HFC-365mfc at the bottom of the extractive distillation tower 1 enters the interior of the extractant recovery tower 2. During the separation process, the product at the bottom of the extractant recovery tower 2 is mainly the extractant n-pentanol, and the product at the top of the extractant recovery tower 2 is mainly HFC-365mfc. During the separation process, the overall temperature of the extractant recovery tower 2 is higher than the overall temperature of the extractive distillation tower 1, so as to ensure that the extractant recovery tower 2 can volatilize and separate HFC-365mfc when heated. The prior art will not be described in detail.

[0036] It should be noted that, since the temperature of the bottom product of the extractant recovery tower 2 entering the reboiler 21 for heating is higher than the overall temperature of the extractive distillation tower 1, after the reboiler 21 heats the extractant of the bottom product of the extractant recovery tower 2, a part of the extractant can enter the interior of the guide chamber 32 through the first feed pipe 35, and the other part of the extractant enters the interior of the first reflux tank 22, wherein the internal extractant entering the guide chamber 32 will preferentially heat the material inside the buffer chamber 33 through the heat-conducting baffle 31, and then the material inside the buffer chamber 33 will heat the bottom product of the extractive distillation tower 1 entering the heating chamber 34 through another heat-conducting baffle 31. The purpose of this is, on the one hand, since the temperature of the extractant after being heated by the reboiler 21 is higher than the temperature of the extractive distillation tower 1, it is avoided to directly heat the bottom product of the extractive distillation tower 1 entering the heating chamber 34, and to prevent n-pentanol from entering the heating chamber 34. The higher temperature of HFC-365mfc can separate more HFC-365mfc gas, avoiding the low HFC-365mfc content in the material entering the extractant recovery tower 2 affecting the separation efficiency. On the other hand, the internal extractant entering the guide cavity 32 can heat the material inside the buffer cavity 33 through the heat-conducting partition 31, and can heat the top product HFC-365mfc of the extractant recovery tower 2 entering the buffer cavity 33, avoiding the HFC-365mfc product from changing from gas to liquid due to heat loss during transportation. The HFC-365mfc entering the buffer cavity 33 can enter the extractive distillation tower 1 through the second discharge pipe 37 and the first condenser 11, and can heat the extractive distillation tower 1 to ensure the reaction temperature inside the extractive distillation tower 1. Therefore, the heating of the two towers can be achieved through a reboiler 21, thereby reducing energy loss and reducing costs.

[0037] The present invention is provided with a splitter tank 3. After the reboiler 21 heats the extractant of the bottom product of the extractant recovery tower 2, a part of the extractant can enter the interior of the guide chamber 32 through the first feed pipe 35. The extractant in the guide chamber 32 can first heat the material in the buffer chamber 33 through the heat-conducting partition 31. Then, the material in the buffer chamber 33 heats the bottom product of the extractive distillation tower 1 entering the heating chamber 34 through another heat-conducting partition 31. The purpose is to avoid directly heating the bottom product of the extractive distillation tower 1 entering the heating chamber 34, and to prevent the n-pentanol and HFC-365mfc entering the heating chamber 34 from being separated into a relatively high temperature. On the one hand, the HFC-365mfc gas can be removed to avoid the low HFC-365mfc content in the material entering the extractant recovery tower 2 affecting the separation efficiency. On the other hand, the top product of the extractant recovery tower 2 entering the buffer chamber 33 can be heated to avoid the top product of the extractant recovery tower 2 from changing from gas to liquid due to heat loss during transportation, which is convenient for subsequent use. The product entering the buffer chamber 33 can enter the extractive distillation tower 1 through the second discharge pipe 37 and the first condenser 11, and can heat the extractive distillation tower 1 to ensure the reaction temperature inside the extractive distillation tower 1. The heating of the two towers can be achieved through a reboiler 21, which reduces energy loss and reduces costs. Embodiment 2

[0038] When the extractive distillation tower separates the azeotropic mixture of HCFC-141b and HFC-365mfc by the extractant, it may be affected by factors such as leakage or insufficient gas-liquid two-phase mass transfer, resulting in the bottom product of the extractive distillation tower being mixed with some HCFC-141b, causing the mixed material entering the extractant recovery tower to have HCFC-141b when separating HFC-365mfc and the extractant, affecting the separation quality.

[0039] Liquid leakage refers to the phenomenon that the liquid fails to form a normal liquid layer on the tower plate, but directly leaks into the lower layer through the holes on the tower plate (such as sieve holes, float valve gaps, etc.) or the channel flow channels of the packing layer, rather than flowing according to the designed path. This will destroy the ideal contact state between the gas and liquid phases. The causes are: the gas phase load is too low, resulting in insufficient rising steam, which cannot effectively support the liquid on the tower plate, causing the liquid to leak from the holes; or the liquid phase load is too large, resulting in the liquid layer on the tower plate being too thick or the flow rate being too large, exceeding the design requirements, overcoming the gas support force, and the liquid is forced to leak out of the holes.

[0040] See also Figures 1 to 3 , the connection position of the second feed pipe 38 and the extractant recovery tower 2 is higher than the connection position of the third discharge pipe 310 and the extractant recovery tower 2; The purpose is to ensure that the material entering the second feed pipe 38 is the top product HFC-365mfc of the extractant recovery tower 2.

[0041] like Figure 3 As shown, each guide tube 311 is arranged at an angle, and the connection position between the guide tube 311 and the second discharge tube 37 is higher than the connection position between the guide tube 311 and the heating chamber 34; The purpose of such arrangement is to prevent the internal material of the buffer chamber 33 from flowing into the extraction distillation tower 1 through the second discharge pipe 37 in a direction corresponding to the connection port between the flow guide pipe 311 and the second discharge pipe 37 , thereby preventing the internal material of the buffer chamber 33 from entering the heating chamber 34 .

[0042] The connection positions of the third feed pipe 39 and the third discharge pipe 310 with the heating chamber 34 are lower than the connection position of the guide pipe 311 with the heating chamber 34, so as to prevent the liquid in the heating chamber 34 from entering the guide pipe 311; Since the temperature of the extractant after being heated by the reboiler 21 is higher than the temperature of the extractive distillation tower 1, the internal extractant entering the guide chamber 32 will preferentially heat the material inside the buffer chamber 33 through the heat-conducting baffle 31, and then the material inside the buffer chamber 33 will heat the bottom product of the extractive distillation tower 1 entering the heating chamber 34 through another heat-conducting baffle 31, so that the internal temperature of the buffer chamber 33 is higher than the internal temperature of the heating chamber 34. The temperature is proportional to the pressure, resulting in the internal pressure of the buffer chamber 33 being greater than the internal pressure of the heating chamber 34.

[0043] The internal extractant entering the guide chamber 32 will first heat the material inside the buffer chamber 33 through the heat-conducting baffle 31, in order to keep HFC-365mfc in a gaseous state, facilitate the subsequent mixing and coexistence with gaseous HCFC-141b to maintain stability and prevent HCFC-141b from diffusing.

[0044] It should be noted that part of the HFC-365mfc product at the top of the extractant recovery tower 2 can enter the second feed pipe 38, and the other part of the HFC-365mfc can enter the third reflux tank 25 after being condensed by the third condenser 24. The HFC-365mfc entering the second feed pipe 38 can enter the buffer chamber 33. Since the temperature inside the buffer chamber 33 is higher than the temperature inside the heating chamber 34, the internal pressure of the buffer chamber 33 is greater than the internal pressure of the heating chamber 34, and the pressure is proportional to the flow rate, resulting in the HFC-365mfc in the buffer chamber 33 remaining in the gas phase entering the extractive distillation tower 1 from the second discharge pipe 37 at a higher flow rate. Due to the high flow rate, the pressure at the connection between the second discharge pipe 37 and the guide pipe 311 will become weak, and since there is a certain temperature and pressure inside the heating chamber 34, the gas volatilized by the heat of the substance entering the heating chamber 34 can enter the second discharge pipe 37 through the guide pipe 311.

[0045] By selecting heat-conducting baffles 31 with different thermal conductivities and setting the height of the buffer chamber 33 to adjust the degree of heating of the heating chamber 34 by the buffer chamber 33, the prior art will not be described in detail. The internal temperature of the heating chamber 34 should meet the reaction temperature inside the extractive distillation tower 1 and be lower than the reaction temperature inside the extractant recovery tower 2. The purpose is to ensure that after the material inside the heating chamber 34 is heated, HCFC-141b can be volatilized preferentially. Since HCFC-141b and HFC-365mfc have strong coexistence without the interference of the extractant, When the HFC-365mfc entering the second discharge pipe 37 flows through the connection between the second discharge pipe 37 and the draft pipe 311, if HCFC-141b is volatilized in the heating chamber 34, the HCFC-141b volatilized in the heating chamber 34 can be carried by the coexistence of HCFC-141b and HFC-365mfc to re-enter the extractive distillation tower 1 for separation, thereby effectively reducing the content of HCFC-141b in the material entering the extractant recovery tower 2 and improving the separation quality.

[0046] In the present invention, by setting the guide pipe 311, the top product part of the extractant recovery tower 2 can enter the second feed pipe 38 and the buffer chamber 33. Since the temperature inside the buffer chamber 33 is higher than the temperature inside the heating chamber 34, the internal pressure of the buffer chamber 33 is greater than the internal pressure of the heating chamber 34, resulting in the top material in the buffer chamber 33 that is in the gas phase entering the extractive distillation tower 1 from the second discharge pipe 37 at a higher flow rate, resulting in the pressure at the connection between the second discharge pipe 37 and the guide pipe 311 being weakened, and due to the heating chamber 34 There is a certain temperature and pressure inside, which causes the top material of the extracting distillation tower 1 that enters the heating chamber 34 to volatilize due to heat, enters the second discharge pipe 37 through the guide pipe 311 in a gaseous state, coexists with the top product of the extractant recovery tower 2, and re-enters the extracting distillation tower 1 for separation. The coexistence of the top product of the extractant recovery tower 2 and the top material of the extracting distillation tower 1 can reduce the content of the top material of the extracting distillation tower 1 in the material entering the extractant recovery tower 2, and can improve the separation quality of the extractant recovery tower 2.

[0047] Finally, it should be noted that the above description is only a preferred embodiment of the present invention and is not intended to limit the present invention. Although the present invention has been described in detail with reference to the aforementioned embodiments, those skilled in the art can still modify the technical solutions described in the aforementioned embodiments or replace some of the technical features therein by equivalents. Any modification, equivalent replacement, improvement, etc. made within the spirit and principle of the present invention shall be included in the protection scope of the present invention.

Claims

1. An extractive distillation device, comprising an extractive distillation tower (1) and an extractant recovery tower (2), characterized in that: The bottom discharge port of the extractant recovery tower (2) is connected to a reboiler (21), and the reboiler (21) is connected to the extractive distillation tower (1) via a splitter tank (3). Both the bottom product and the top product of the extractant recovery tower (2) can enter the splitter tank (3), wherein the bottom product of the extractant recovery tower (2) can heat the top product of the extractant recovery tower (2) in the splitter tank (3) after being heated by the reboiler (21), and the top product of the extractant recovery tower (2) in the splitter tank (3) can enter the extractive distillation tower (1) to heat the substances in the extractive distillation tower (1); Two heat-conducting baffles (31) are fixedly connected to the interior of the diverter tank (3), and the two heat-conducting baffles (31) can divide the interior of the diverter tank (3) into a diversion chamber (32), a buffer chamber (33) and a heating chamber (34) from bottom to top. A first feed pipe (35) connected to the diversion chamber (32) is provided at the bottom of the diverter tank (3), and a first discharge pipe (36) connected to the diversion chamber (32) is provided on the outside of the diverter tank (3). A second discharge pipe (37) connected to the buffer chamber (33) is provided on the top of the diverter tank (3); a second feed pipe (38) connected to the buffer chamber (33) is provided on the outside of the diverter tank (3); a third feed pipe (39) and a third discharge pipe (310) connected to the heating chamber (34) are also provided on the outside of the diverter tank (3); and at least two guide pipes (311) connected to the second discharge pipe (37) and the heating chamber (34) are provided on the top of the diverter tank (3).

2. The extractive distillation device according to claim 1, characterized in that: The discharge port of the reboiler (21) is connected to a first reflux tank (22) and is in communication with a first feed pipe (35). The first discharge pipe (36) is in communication with a bottom reflux port of the extractant recovery tower (2). The bottom product of the extractant recovery tower (2) can enter the interior of the reboiler (21). After being heated, part of the product entering the interior of the reboiler (21) enters the interior of the guide chamber (32) through the first feed pipe (35), and the other part enters the interior of the first reflux tank (22). The first reflux tank (22) is connected to the extractant feed port of the extractive distillation tower (1) through a reflux pump (23). The product entering the interior of the first reflux tank (22) can enter the interior of the extractive distillation tower (1) through the reflux pump (23), and the product entering the interior of the guide chamber (32) can enter the interior of the extractive distillation tower (2) through the first discharge pipe (36).

3. The extractive distillation device according to claim 2, characterized in that: The bottom discharge port of the extractive distillation tower (1) is connected to the third feed pipe (39), and the third discharge pipe (310) is connected to the feed port of the extractant recovery tower (2). The bottom product of the extractive distillation tower (1) can enter the interior of the heating chamber (34) through the third feed pipe (39), and the product entering the interior of the heating chamber (34) can enter the interior of the extractant recovery tower (2) through the third discharge pipe (310).

4. The extractive distillation device according to claim 3, characterized in that: The top of the extractant recovery tower (2) is connected to the second feed pipe (38), and the second discharge pipe (37) is connected to the bottom reflux port of the extractive distillation tower (1) through the first condenser (11). The top product of the extractant recovery tower (2) can enter the interior of the buffer chamber (33) through the second feed pipe (38), and the product entering the interior of the buffer chamber (33) can enter the interior of the extractive distillation tower (1) through the second discharge pipe (37) and the first condenser (11).

5. The extractive distillation device according to claim 4, characterized in that: The connection position between the second feed pipe (38) and the extractant recovery tower (2) is higher than the connection position between the third discharge pipe (310) and the extractant recovery tower (2); each of the flow guide pipes (311) is arranged at an inclination; the connection position between the flow guide pipe (311) and the second discharge pipe (37) is higher than the connection position between the flow guide pipe (311) and the heating chamber (34); and the connection positions between the third feed pipe (39) and the third discharge pipe (310) and the heating chamber (34) are both lower than the connection position between the flow guide pipe (311) and the heating chamber (34).

6. The extractive distillation device according to claim 5, characterized in that: The top discharge port of the extractive distillation tower (1) is connected to a second condenser (12), the discharge port of the second condenser (12) is connected to a second reflux tank (13), the discharge port of the second reflux tank (13) is connected to a first collecting tank (14), and is in communication with the top reflux port of the extractive distillation tower (1).

7. The extractive distillation device according to claim 6, characterized in that: The top product of the extractive distillation tower (1) can enter the interior of the second reflux tank (13) after being condensed by the second condenser (12); part of the product entering the interior of the second reflux tank (13) can enter the interior of the first collecting tank (14), and the other part can enter the interior of the extractive distillation tower (1).

8. The extractive distillation device according to claim 7, characterized in that: The top discharge port of the extractant recovery tower (2) is connected to a third condenser (24), the discharge port of the third condenser (24) is connected to a third reflux tank (25), the discharge port of the third reflux tank (25) is connected to a second collecting tank (26), and is in communication with the top reflux port of the extractant recovery tower (2).

9. The extractive distillation device according to claim 8, characterized in that: Part of the top product of the extractant recovery tower (2) can enter the second feed pipe (38), and another part can enter the third reflux tank (25) after being condensed by the third condenser (24). Part of the product that enters the third reflux tank (25) can enter the second collection tank (26), and another part can enter the extractant recovery tower (2).

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