A micro-distillation device and method for efficiently separating near-boiling point mixtures

Abstract

The present invention discloses a micro-distillation device for efficiently separating near-boiling point mixtures, which includes a feed plunger pump, a feed section heat exchanger, a micro-distillation tower, a condenser, a reflux peristaltic pump and a reboiler; at least one of a microscale packing structure or a microscale tray structure is provided in the micro-distillation tower, and the gas phase and the liquid phase flow in opposite directions in the micro-distillation tower, and contact and mass transfer are carried out on the microscale packing structure and / or the microscale tray structure. The micro-distillation device of the present invention utilizes a variety of microstructures such as trays and packings to guide and strengthen the counter-flow of gas-liquid two-phase materials, and improves the gas-liquid mass transfer efficiency and heat exchange efficiency by increasing the contact area between the gas-liquid two-phases and enhancing the disturbance of the gas-liquid flow, thereby realizing micro-distillation separation with high volumetric efficiency. Compared with traditional distillation operations, the present invention has the advantages of high mass and heat transfer, simple operation, rapid processing, and low cost.

Description

Technical Field

[0001] The invention belongs to the technical field of chemical separation and purification, and particularly relates to a micro-distillation device and method for efficiently separating near-boiling point mixtures. Background Art

[0002] Distillation is a method of separating components in a liquid mixture by exploiting their varying volatility. The distillation process is widely used due to its simplicity and excellent separation efficiency. Distillation is typically performed in a distillation tower, where the gas and liquid phases meet in countercurrent flow, allowing heat and mass transfer between the phases. This allows the volatile component to accumulate in the vapor phase at the top of the tower, while the less volatile component accumulates in the liquid phase at the bottom.

[0003] In recent years, microchemical processes have garnered widespread attention due to their small size, low energy consumption, high efficiency, and inherent safety. As a new research direction within chemical engineering, microchemical technology has been vigorously developed, and the microstructuring of traditional chemical equipment has become a key development trend. However, traditional distillation equipment is bulky, inconvenient to operate, and requires high fixed asset investment and energy consumption, making it unsuitable for use with microreactors. Therefore, the lack of microdistillation equipment has limited the development of microchemical technology.

[0004] Patent CN112843765 proposes a micro-scale distillation device and process for binary systems with large differences in boiling points, and the separation effect for difficult-to-separate systems is not significant enough. Patent CN208525866 proposes a distillation tube with a float chamber structure, but it is prone to liquid overflow, and the production and processing of special-shaped tubes is difficult. Patent CN105478012 proposes a method for treating Chinese medicine extracts using microfiltration-membrane distillation technology, which has high separation efficiency and can effectively prevent or reduce membrane pollution, but the membrane distillation flux is small and the production efficiency is limited. Patent CN109569002A proposes the use of a microchannel distillation tower to purify crude trimethylaluminum. By improving the distillation tower structure and optimizing the uniformity of the gas-liquid distribution in the tube body, efficient purification of trimethylaluminum can be achieved, but the micro-distillation tower involved can only be used for intermittent distillation and cannot achieve a continuous distillation process.

[0005] In summary, in order to solve the technical difficulties in separation and purification of near-boiling point mixtures, it is necessary to develop and design a simple and efficient micro-distillation structure as well as its application method, device and process. Summary of the Invention

[0006] In response to the problems existing in the background technology, the present invention provides a micro-distillation device and method for efficiently separating near-boiling point mixtures. The high specific surface area of ​​the flow channel structure, tower plate structure or packing structure with characteristic dimensions at the micron level promotes the contact and mass transfer of gas and liquid phases on its surface, thereby achieving efficient distillation separation of near-boiling point mixtures.

[0007] The present invention first provides a micro-distillation device for efficiently separating near-boiling point mixtures, which includes a feed plunger pump, a feed section heat exchanger, a micro-distillation tower, a condenser, a reflux peristaltic pump and a reboiler; the feed plunger pump is connected to the feed section heat exchanger through a pipeline, and the feed section heat exchanger is connected to the feed port of the micro-distillation tower through a pipeline; the gas phase outlet at the top of the micro-distillation tower is connected to the condenser through a pipeline, and the condenser is provided with a reflux port and a top material outlet, the reflux port on the condenser is connected to the reflux port at the top of the distillation tower through the reflux peristaltic pump, the liquid phase outlet at the bottom of the micro-distillation tower is respectively connected to the reboiler and the bottom material outlet, the reboiler is connected to the reboiled gas inlet of the micro-distillation tower, and at least one microscale structure is provided in the micro-distillation tower, the gas phase and the liquid phase flow in countercurrent in the micro-distillation tower, and contact and mass transfer are carried out on the microscale structure; the microscale structure is a microscale packing structure, a microscale tower plate structure or a microscale spiral flow channel structure.

[0008] Preferably, the micro-distillation tower is a tubular structure with an inner diameter of 3 to 20 mm, an outer diameter of 5 to 25 mm, and a length of 50 to 200 mm; a gas phase outlet is provided at the upper end of the micro-distillation tower, a liquid phase outlet is provided at the lower end, and a material inlet, a reflux liquid inlet, and a reboiled gas inlet are provided on the side wall of the distillation tower.

[0009] In a preferred embodiment of the present invention, the micro-scale tray structure is a hole-type sieve plate, the hole structure diameter of the hole-type sieve plate is 0.1 to 3 mm, the spacing is 0.1 to 3 mm, and the tray spacing is 3 to 10 mm.

[0010] In a preferred embodiment of the present invention, the micro-scale tower plate structure is a trough-type sieve plate, the width of the trough structure on the trough-type sieve plate is 0.2 to 10 mm, the aspect ratio is 1 to 50, the trough structure spacing is 0.5 to 5 mm, the tower plate spacing is 3 to 20 mm, and the angle between the trough directions of the trough structures on two adjacent layers of trough-type sieve plates is 1 to 90°.

[0011] In a preferred embodiment of the present invention, the microscale spiral flow channel structure is integrated with the microdistillation column. A spiral first channel is defined within the microdistillation column, with its axis as the centerline. The first channel has a circular cross-section and a diameter of 0.5 to 5 mm. Multiple linear second channels are defined within the microdistillation column, parallel to the axis. The second channels have circular cross-sections, a diameter of 0.1 to 3 mm, and are spaced 0.1 to 3 mm apart. The first and second channels form a microscale spiral flow channel structure and are connected at multiple locations within the column.

[0012] In a preferred embodiment of the present invention, the micro-scale filler structure is a cylindrical hollow bulk filler, and the specific surface area of ​​the filler is greater than 1500m 2 / m3 The filler has a diameter of 0.5 to 5 mm and an aspect ratio of 1 to 10.

[0013] Preferably, the micro-distillation tower and micro-scale structure are prepared by 3D printing or CNC machining.

[0014] The present invention also discloses an efficient micro-distillation method based on the micro-distillation device, which comprises the following steps:

[0015] (1) Pretreatment: The material to be distilled and separated is transported through a feed pipe by a feed plunger pump and is heated in a feed section heat exchanger to form a gas-liquid mixture;

[0016] (2) Distillation separation: The gas-liquid mixture enters the micro-distillation tower through the feed port of the micro-distillation tower for distillation. The gas phase material at the top of the micro-distillation tower enters the condenser through the gas phase outlet. A part of the condensed liquid phase material is extracted as the product through the top material outlet of the tower, and the remaining part is returned to the reflux port of the top of the micro-distillation tower through the reflux peristaltic pump as the reflux material. The reflux liquid phase material flows downward along the micro-scale structure in the tower and at the same time contacts and transfers mass with the gas phase material flowing upward; the liquid phase material at the bottom of the micro-distillation tower flows out through the liquid phase outlet, a part of it is extracted as the product through the bottom material outlet of the tower, and the other part enters the reboiler, is heated and vaporized in the reboiler, and returns to the reboiled gas inlet at the bottom of the micro-distillation tower.

[0017] Preferably, the feed rate of the feed plunger pump is 0.1 μL / min to 50 mL / min. Preferably, the liquid content of the gas-liquid mixture generated after heat exchange in the feed section heat exchanger is 0 to 60%.

[0018] Preferably, the outlet temperature of the hot stream of the feed section heat exchanger is 40-150°C. Preferably, the micro-distillation tower is placed vertically during use, and the operating pressure is 1-2.5 atm. Preferably, the reflux ratio of the micro-distillation tower is 0.3-10.

[0019] Compared with the prior art, the present invention has the following advantages:

[0020] (1) The micro-distillation device of the present invention utilizes various microstructures, such as trays and packings, to guide and enhance the countercurrent flow of gas-liquid materials. By increasing the gas-liquid contact area and enhancing the disturbance of the gas-liquid flow, the gas-liquid mass transfer efficiency and heat exchange efficiency are improved, achieving high-volume-efficiency micro-distillation separation. Compared with traditional distillation operations, the present invention has the advantages of high mass and heat transfer, simple operation, rapid processing, and low cost.

[0021] (2) When the micro-distillation device of the present invention is used to separate toluene from trimethylaluminum, n-hexane-ethyl acetate and other near-boiling point, difficult-to-separate systems, it can achieve a single component purity of more than 99.9%.

[0022] (3) The micro-distillation device of the present invention can be used in conjunction with a variety of microreactors to form a micro-chemical production device "desktop factory", which has the advantage of intrinsic safety and can be used for the separation and purification process in the continuous production of high-value chemicals and hazardous chemicals. BRIEF DESCRIPTION OF THE DRAWINGS

[0023] Figure 1 It is a vertical operation schematic diagram of the micro-distillation device of the present invention.

[0024] Figure 2 It is a cross-sectional view of the micro-distillation device of the present invention.

[0025] Figure 3 It is a schematic structural diagram of the hole-type sieve plate of the micro-distillation device of the present invention.

[0026] Figure 4 yes Figure 3 Plan view at section AA.

[0027] Figure 5 It is a structural schematic diagram of the trough-type sieve plate of the micro-distillation device of the present invention.

[0028] Figure 6 yes Figure 5 Plan view at section AA.

[0029] Figure 7 yes Figure 5 Stereoscopic view at section AA.

[0030] Figure 8 It is a structural schematic diagram of the spiral channel of the micro-distillation device of the present invention.

[0031] Figure 9 yes Figure 8 Section view at section AA.

[0032] Figure 10 It is a schematic structural diagram of the bulk packing of the micro-distillation device of the present invention.

[0033] in:

[0034] 1-feed pipe, 2-feed plunger pump, 3-delivery pipe, 4-feed section heat exchanger, 5-gas-liquid mixture, 6-feed port, 7-gas phase product, 8-condenser, 9-top product, 10-reflux liquid, 11-reflux peristaltic pump, 12-reflux liquid inlet, 13-micro-distillation tower, 14-liquid phase outlet, 15-reboiled material, 16-reboiler, 17-reboiled gas inlet. DETAILED DESCRIPTION

[0035] The present invention will be further described and illustrated below in conjunction with specific embodiments. The embodiments are merely illustrative of the present disclosure and do not limit its scope. The technical features of the various embodiments of the present invention may be combined accordingly, provided that there is no conflict between them.

[0036] like Figure 1 As shown, the micro-distillation device for efficiently separating near-boiling point mixtures of the present invention mainly comprises a feed plunger pump 2, a feed section heat exchanger 4, a micro-distillation tower 13, a condenser 8, a reflux peristaltic pump 11 and a reboiler 16; the feed plunger pump 2 is connected to the feed section heat exchanger 4 through a pipeline, and the feed section heat exchanger 4 is connected to the feed port of the micro-distillation tower 13 through a pipeline; the gas phase outlet at the top of the micro-distillation tower is connected to the condenser 8 through a pipeline, and the condenser 8 is provided with a reflux port and a tower top material outlet, and the condenser The reflux port on 8 is connected to the reflux port at the top of the distillation tower through the reflux peristaltic pump 11, and the liquid phase outlet at the bottom of the micro-distillation tower is respectively connected to the reboiler 16 and the bottom material outlet, and the reboiler 16 is connected to the reboiled gas inlet of the micro-distillation tower 13. At least one microscale structure is provided in the micro-distillation tower, and the gas phase and the liquid phase flow in countercurrents in the micro-distillation tower, and contact and mass transfer are carried out on the microscale structure; the microscale structure is a microscale packing structure, a microscale tower plate structure or a microscale spiral flow channel structure.

[0037] like Figure 2 FIG. 1 is a schematic diagram of a micro-distillation apparatus. The micro-distillation tower 13 of the present invention is provided with at least one of a micro-scale packing structure and a micro-scale tray structure. The micro-scale tray structure is built into the micro-distillation tower, and the micro-scale packing structure is introduced through the feed port of the micro-distillation tower. Generally, either the micro-scale tray structure or the micro-scale packing structure is sufficient; however, in certain operating conditions, both can be used to achieve a more ideal separation effect.

[0038] Typically, but not limiting, the micro-distillation column (including a built-in micro-scale tray structure or a micro-scale spiral flow channel structure) and the micro-scale packing structure of the present invention can be produced by 3D printing or CNC machining. Preferably, the micro-distillation column is a tubular structure with an inner diameter of 3 to 20 mm, an outer diameter of 5 to 25 mm, and a length of 50 to 200 mm.

[0039] like Figure 3 and Figure 4 As shown, in a preferred embodiment of the present invention, the micro-scale tower plate structure is a hole-type sieve plate, the hole structure diameter of the hole-type sieve plate is 0.1 to 3 mm, the spacing is 0.1 to 3 mm, and the tower plate spacing is 3 to 10 mm.

[0040] like Figure 5-Figure 7As shown, in another preferred embodiment of the present invention, the microscale tower plate structure is a trough-type sieve plate, the width of the trough structure on the trough-type sieve plate is 0.2-10 mm, the aspect ratio is 1-50, the trough structure spacing is 0.5-5 mm, the tower plate spacing is 3-20 mm, and the trough direction staggered angle (the included angle) of the trough structure on two adjacent layers of trough-type sieve plates is 1-90°.

[0041] like Figure 8 and Figure 9 As shown, efficient separation can also be achieved by providing a microscale spiral flow channel structure in the micro-distillation tower 13. In one embodiment of the present invention, the microscale spiral flow channel structure and the micro-distillation tower are an integrated structure, and a spiral first channel (mainly serving as a liquid flow channel) with its axis as the center line is provided inside the micro-distillation tower, and the cross section of the first channel is circular with a diameter of 0.5 to 5 mm; a plurality of straight second channels (mainly serving as gas flow channels) parallel to its axis are provided inside the micro-distillation tower, and the cross section of the second channel is circular with a diameter of 0.1 to 3 mm and a spacing of 0.1 to 3 mm; the first channel and the second channel constitute a microscale spiral flow channel structure, and the first channel and the second channel are connected at multiple locations in the tower.

[0042] The micro-distillation tower 13 can also be provided with a micro-scale packing structure to achieve efficient separation, such as Figure 10 As shown in one embodiment, the micro-scale filler structure is a columnar hollow bulk filler, which is formed by stacking multiple rectangular parallelepipeds at an interlaced angle of 1 to 90 degrees, and its specific surface area is greater than 1500m 2 / m 3 The filler has a diameter of 0.5 to 5 mm and an aspect ratio of 1 to 10.

[0043] Based on the micro-rectification device of the present invention, the efficient micro-rectification method of the present invention can be implemented according to the following steps:

[0044] (1) Pretreatment: The material to be distilled and separated is fed through a feed pipe 1 by a feed plunger pump 2 and is heat exchanged in a feed section heat exchanger 4 to generate a gas-liquid mixture 5;

[0045] (2) Distillation separation: The gas-liquid mixture enters the micro-distillation tower 13 through the feed port 6 of the micro-distillation tower for distillation, and the gas phase product 7 at the top of the micro-distillation tower enters the condenser 8 through the gas phase outlet. A part of the condensed liquid phase material is extracted as the product through the top material outlet of the tower, and the remaining part is returned to the reflux liquid inlet 12 at the top of the micro-distillation tower through the reflux peristaltic pump 11 as the reflux material. The reflux liquid phase material flows downward along the micro-scale packing structure or micro-scale tower plate structure in the tower, and at the same time contacts and transfers mass with the gas phase material flowing upward; the liquid phase material at the bottom of the micro-distillation tower 13 flows out through the liquid phase outlet 14, a part of it is extracted as the product through the bottom material outlet of the tower, and the other part enters the reboiler 16, is heated and vaporized in the reboiler, and returns to the reboiled gas inlet 17 at the bottom of the micro-distillation tower.

[0046] The distillation method of the present invention can be further implemented according to the following optional or preferred operating conditions, for example, the feed rate of the feed plunger pump can be 0.1 μL / min to 50 mL / min; the liquid content of the gas-liquid mixture generated after heat exchange in the feed section heat exchanger can be 0 to 60%; the outlet hot flow temperature of the feed section heat exchanger can be 40 to 150°C; the micro-distillation tower is placed vertically when used, and is operated at normal pressure or slightly positive pressure, with an operating pressure of 1 to 2.5 atm; the reflux ratio of the micro-distillation tower can be 0.3 to 10.

[0047] Comparative Example 1

[0048] The micro-distillation tower used in this comparative example has an inner diameter of 12 mm, an outer diameter of 14 mm, and a length of 140 mm. The ceramic balls with a diameter of 3 mm are used as fillers. The micro-distillation tower is used to separate an equimolar mixture of toluene and trimethylaluminum. Figure 1 As shown, the toluene-trimethylaluminum mixture to be separated enters the feed section heat exchanger 4 from the feed pipe 1 through the feed plunger pump 2 and the delivery pipe 3, and the generated gas-liquid mixture 5 enters the micro-distillation tower through the feed port 6. The gas phase product 7 rich in high-volatile substances enters the condenser 8. Part of the condensed liquid phase material is extracted as the top product 9, and the remaining material 10 flows back to the reflux port 12 of the micro-distillation tower through the reflux peristaltic pump 11, flows from top to bottom along the tower, and flows out through the liquid phase outlet 14 at the bottom of the tower. Part of it is extracted as the bottom material, and the remaining material 15 is reheated in the reboiler 16 and returned to the micro-distillation tower through the reboiled gas inlet 17.

[0049] The feed rate of the feed plunger pump is 10 mL / min, the outlet hot flow temperature of the heat exchanger is 85° C., and the reflux ratio of the micro-distillation tower is 5.3.

[0050] After the above process, the molar fraction of trimethylaluminum at the top of the tower is 0.118, and the molar fraction of trimethylaluminum at the bottom of the tower is 0.908.

[0051] Example 1

[0052] The only difference between this embodiment and comparative example 1 is that the micro-rectification tower used is selected as Figure 3 and Figure 4 The hole-type sieve plate structure shown has a hole structure diameter of 1 mm, a hole spacing of 3 mm, and a tower plate spacing of 5 mm.

[0053] After the above process, the molar fraction of trimethylaluminum at the top of the tower is 0.008, and the molar fraction of trimethylaluminum at the bottom of the tower is 0.995.

[0054] Comparative Example 2

[0055] The difference between this comparative example and comparative example 1 is that the micro-distillation tower used has an inner diameter of 15 mm, an outer diameter of 17 mm, and a length of 150 mm. The separation system is an equimolar n-hexane-cyclohexane aluminum mixture. The feed rate of the feed plunger pump is 1 mL / min, the outlet hot flow temperature of the heat exchanger is 76°C, and the reflux ratio of the micro-distillation tower is 10.

[0056] After the above process, the molar fraction of n-hexane at the top of the tower is 0.833, and the molar fraction of n-hexane at the bottom of the tower is 0.128.

[0057] Example 2

[0058] The only difference between this embodiment and comparative example 2 is that the micro-rectification tower used is selected as Figure 5-Figure 7 The slot-type sieve plate structure shown has a slot structure width of 1 mm, a slot spacing of 2 mm, a slot number of 7, a tower plate spacing of 5 mm, and an adjacent sieve plate staggered angle of 90°.

[0059] After the above process, the molar fraction of n-hexane at the top of the tower is 0.956, and the molar fraction of n-hexane at the bottom of the tower is 0.101.

[0060] Comparative Example 3

[0061] The difference between this comparative example and comparative example 1 is that the micro-distillation tower used has an inner diameter of 20 mm, an outer diameter of 23 mm, and a length of 200 mm, the separation system is an equimolar mixture of n-hexane and ethyl acetate, the feed rate of the feed plunger pump is 12 mL / min, the outlet hot flow temperature of the heat exchanger is 75°C, and the reflux ratio of the micro-distillation tower is 5.8.

[0062] After the above process, the molar fraction of n-hexane at the top of the tower is 0.667, and the molar fraction of n-hexane at the bottom of the tower is 0.428.

[0063] Example 3

[0064] The only difference between this embodiment and comparative example 3 is that the micro-rectification tower used is selected as Figure 8 and 9The microscale spiral flow channel structure shown is an integrated structure with the micro-distillation tower. The microscale spiral flow channel structure includes a spiral first channel (mainly serving as a liquid flow channel) with the axis of the micro-distillation tower as the center line, and multiple straight second channels parallel to the axis direction (mainly serving as gas flow channels). The first channel and the second channel are connected at multiple locations in the tower; the diameter of the spiral first channel is 3.6 mm, the second channel is 1.5 mm, and the spacing between the second channels is 1 mm.

[0065] After the above process, the molar fraction of n-hexane at the top of the tower is 0.999, and the molar fraction of n-hexane at the bottom of the tower is 0.001.

[0066] Comparative Example 4

[0067] The difference between this comparative example and comparative example 3 is that the separation system is an equimolar 1,2-butanediol-ethylene glycol mixture, the feed rate of the feed plunger pump is 15 mL / min, the outlet hot flow temperature of the heat exchanger is 180°C, and the reflux ratio of the micro-distillation tower is 5.

[0068] After the above process, the mole fraction of ethylene glycol at the top of the tower is 0.539, and the mole fraction of ethylene glycol at the bottom of the tower is 0.748.

[0069] Example 4

[0070] The only difference between this embodiment and Comparative Example 4 is that the filler used is Figure 10 The cylindrical hollow bulk packing shown has an internal component staggered angle of 60° and a specific surface area of ​​1800m 2 / m 3 , the filler diameter is 5mm and the aspect ratio is 2.

[0071] After the above process, the mole fraction of ethylene glycol at the top of the tower is 0.021, and the mole fraction of ethylene glycol at the bottom of the tower is 0.999.

[0072] From the comprehensive experimental results and the comparison between the examples and the comparative examples, it can be seen that when the present invention is applied to the separation of near-boiling point mixtures, its separation effect is significantly better than that of a conventional small distillation tower under the same operating conditions.

[0073] It should be noted that the embodiments described above are only used to explain the present invention and do not constitute any limitation of the present invention. The present invention has been described with reference to typical embodiments, but it should be understood that the words used therein are descriptive and explanatory words, rather than restrictive words. The present invention may be modified as specified within the scope of the claims of the present invention, and the present invention may be revised without departing from the scope and spirit of the present invention. Although the present invention described therein relates to specific methods, materials and embodiments, it does not mean that the present invention is limited to the specific examples disclosed therein. On the contrary, the present invention can be extended to all other methods and applications with the same function.

Claims

1. A micro-distillation device for efficiently separating near-boiling point mixtures, characterized by: The invention comprises a feed plunger pump, a feed section heat exchanger, a micro-rectification tower, a condenser, a reflux peristaltic pump and a reboiler; the feed plunger pump is connected to the feed section heat exchanger through a pipeline, and the feed section heat exchanger is connected to the feed port of the micro-rectification tower through a pipeline; the gas phase outlet at the top of the micro-rectification tower is connected to the condenser through a pipeline, the condenser is provided with a reflux port and a tower top material outlet, the reflux port on the condenser is connected to the reflux port at the top of the distillation tower through the reflux peristaltic pump, the liquid phase outlet at the bottom of the micro-rectification tower is respectively connected to the reboiler and the tower bottom material outlet, the reboiler is connected to the reboiled gas inlet of the micro-rectification tower, and at least one micro-rectification tower is provided in the micro-rectification tower. The micro-distillation tower has a micro-scale structure, in which the gas phase and the liquid phase flow in countercurrents in the micro-distillation tower and contact and transfer mass on the micro-scale structure; the micro-scale structure is a micro-scale spiral flow channel structure; the micro-scale spiral flow channel structure and the micro-distillation tower are an integrated structure, and a spiral first channel with its axis as the center line is provided inside the micro-distillation tower, and the cross-section of the first channel is circular with a diameter of 0.5-5 mm; the micro-distillation tower has a plurality of straight second channels parallel to its axis, and the cross-section of the second channels is circular with a diameter of 0.1-3 mm and a spacing of 0.1-3 mm; the first channel and the second channel constitute a micro-scale spiral flow channel structure, and the first channel and the second channel are connected at multiple locations in the tower.

2. The micro-distillation device for efficiently separating near-boiling point mixtures according to claim 1, characterized in that: The micro-distillation tower is a tubular structure with an inner diameter of 3 to 20 mm, an outer diameter of 5 to 25 mm, and a length of 50 to 200 mm; a gas phase outlet is provided at the upper end of the micro-distillation tower, a liquid phase outlet is provided at the lower end, and a material inlet, a reflux liquid inlet, and a reboiled gas inlet are provided on the side wall of the distillation tower.

3. The micro-distillation device for efficiently separating near-boiling point mixtures according to claim 1, characterized in that: The micro-distillation tower and micro-scale structure are prepared by 3D printing or CNC machining.

4. An efficient micro-distillation method based on the micro-distillation device according to claim 1, characterized in that: The steps include: (1) Pretreatment: The material to be distilled and separated is transported through the feed pipe by the feed plunger pump and is heated in the feed section heat exchanger to generate a gas-liquid mixture; (2) Distillation separation: The gas-liquid mixture enters the micro-distillation tower through the feed port of the micro-distillation tower for distillation. The gas phase material at the top of the micro-distillation tower enters the condenser through the gas phase outlet. A part of the condensed liquid phase material is extracted as the product through the material outlet at the top of the tower, and the remaining part is returned to the reflux port at the top of the micro-distillation tower through the reflux peristaltic pump as the reflux material. The reflux liquid phase material flows downward along the micro-scale structure in the tower and at the same time contacts and transfers mass with the gas phase material flowing upward; the liquid phase material at the bottom of the micro-distillation tower flows out through the liquid phase outlet, a part of it is extracted as the product through the material outlet at the bottom of the tower, and the other part enters the reboiler, is heated and vaporized in the reboiler, and returns to the reboiled gas inlet at the bottom of the micro-distillation tower.

5. The method according to claim 4, characterized in that: The feed rate of the feed plunger pump is 0.1 μL / min~50 mL / min; the liquid content of the gas-liquid mixture generated after heat exchange in the feed section heat exchanger is 0~60%.

6. The method according to claim 4, characterized in that: The outlet hot flow temperature of the feed section heat exchanger is 40-150° C.; the micro-distillation tower is placed vertically during use, and the operating pressure is 1-2.5 atm; the reflux ratio of the micro-distillation tower is 0.3-10.

Images