Single-tower rectification equipment for gamma-butyrolactone and treatment process of gamma-butyrolactone

Abstract

The invention discloses gamma-butyrolactone single-tower rectification equipment and a treatment process thereof, and relates to the technical field of gamma-butyrolactone preparation.The gamma-butyrolactone single-tower rectification equipment comprises a feeding pump, a rectification tower, a first cooler, a second cooler, a hazardous waste storage tank, a finished product storage tank and a vacuum pump, the rectification tower comprises a tower shell, and tower plates are evenly arranged in the tower shell in the height direction; an overflow weir is arranged on one side of the tower plate, and a downflow plate is connected below the overflow weir; bubble cap assemblies are uniformly distributed above the tower plate, and each bubble cap assembly comprises a breather pipe, a rotary steam distribution component and a cyclone structure; the bottom end of the ventilation pipe is fixed at the top of the tower plate and forms a ventilation channel penetrating through the tower plate; the top end of the ventilation pipe is higher than the highest point of the overflow weir. Through structural innovation and process optimization, high purity of the product is guaranteed, energy consumption and material consumption are reduced, high efficiency, intelligence and environmental friendliness are achieved, and an advanced solution is provided for rectification production of gamma-butyrolactone.

Description

Technical Field

[0001] The invention relates to the technical field of gamma-butyrolactone preparation, in particular to single-tower distillation equipment for gamma-butyrolactone and a processing process thereof. Background Art

[0002] Gamma-butyrolactone (GBL), a key chemical intermediate, is widely used in lithium battery solvents, pharmaceutical synthesis, and high-performance polymers. Its distillation purification faces significant challenges: At room temperature, GBL has a viscosity exceeding 200 cP. Viscous drag leads to poor liquid flow, easily forming "dead zones" on the trays and reducing gas-liquid mass transfer efficiency. Furthermore, with a boiling point of 204°C at ambient pressure, GBL is prone to thermal decomposition during high-temperature operation, necessitating a vacuum system to lower its boiling point. However, traditional vacuum distillation towers suffer from short gas-liquid contact time and low mass transfer efficiency.

[0003] After searching, it was found that in the existing technology, distillation towers mostly adopt static adjustment structures (such as the movable plate to adjust the liquid layer in patent CN115337659B and the umbrella-shaped cover air inlet groove design in CN119258573B). Although these structures can partially improve the liquid layer distribution, they have limited adaptability to high-viscosity materials. That is, the fixed overflow weir cannot match the gas velocity changes in real time, resulting in fluctuations in mass transfer efficiency, coarse bubble size, and insufficient gas-liquid contact area. Summary of the Invention

[0004] The object of the present invention is to provide a single-tower distillation device for γ-butyrolactone and a treatment process thereof to solve the problems raised in the above background technology.

[0005] In order to achieve the above-mentioned object of the invention, the present invention adopts the following technical solutions: The present invention provides a single-tower distillation device for γ-butyrolactone, comprising a feeding pump, a distillation tower, a first cooler, a second cooler, a hazardous waste storage tank, a finished product storage tank, and a vacuum pump. The distillation tower comprises a tower shell, the interior of which is evenly provided with tower plates along the height direction, an overflow weir is provided on one side of the tower plate, and a downcomer is connected below the overflow weir; A bubble cap assembly is evenly distributed above the tower plate, and the bubble cap assembly includes a ventilation pipe, a rotating steam distribution component and a cyclone structure; the bottom end of the ventilation pipe is fixed to the top of the tower plate and forms a ventilation channel running through the tower plate, and the top end of the ventilation pipe is higher than the highest point of the overflow weir; the rotating steam distribution component includes a rotating tube rotatably arranged in the ventilation channel, an umbrella-shaped exhaust cover connected to the top of the rotating tube, and a plurality of L-shaped tubes evenly distributed along the outer periphery of the umbrella-shaped exhaust cover, and the bottom end of each L-shaped tube extends below the liquid level of the tower plate; the cyclone structure is composed of a spiral guide plate arranged on the inner wall of the rotating tube, and the spiral guide plate is at a preset angle to the axis of the rotating tube, which can drive the rotating tube to rotate through the flow of steam.

[0006] Furthermore, a liquid layer adjustment system is provided below the tray, comprising: The lifting plate slides with the side wall of the overflow weir, and its vertical movement range covers 20%-50% of the overflow weir height; An air pressure balance plate is arranged parallel to the bottom of the tower plate, the air pressure balance plate is connected to the air path of the ventilation channel through a connecting pipe, and the top end of the connecting pipe is embedded in the ventilation channel; The surface of the downcomer is provided with a guide chute, and the air pressure balance plate is fixedly connected to the lifting plate via a linkage slider extending into the chute; A pressure adaptive spring group is installed between the air pressure balance plate and the tower plate.

[0007] Furthermore, the bottom ends of all L-shaped tubes are connected to an annular reinforcement member, and multiple groups of diffusion holes are evenly opened on the reinforcement member, and the axes of the diffusion holes form a downward inclination angle of 10°-30° with the horizontal direction, and the spacing between adjacent diffusion holes is 3-5 times the aperture; a gap is reserved between the inner wall of the reinforcement member and the outer wall of the ventilation pipe to form a dynamic airflow channel.

[0008] Furthermore, the reinforcing member is connected to the vent pipe via a spiral linkage mechanism, which includes: An inclined closed guide groove is provided on the outer wall of the vent pipe; A guide block fixed to the inner wall of the reinforcement member, the guide block being embedded in the inclined closed guide groove and sliding along the track of the inclined closed guide groove; When the L-shaped tube rotates with the rotating tube, the guide block moves along the inclined closed guide groove, driving the reinforcement component to rotate synchronously and rise and fall periodically along the axial direction of the ventilation tube.

[0009] Furthermore, a convex ring protruding outward is provided in the middle of the rotating tube, and a threaded cover is slidably provided on the rotating tube above the convex ring. The threaded cover is threadedly matched with the top of the ventilation pipe. A lower thrust bearing is provided between the bottom of the convex ring and the top of the ventilation pipe, and an upper thrust bearing is provided between the top of the convex ring and the top of the threaded cover.

[0010] Furthermore, a guide hole is provided at the center of the top of the umbrella-shaped exhaust cover; the cyclone structure includes: A threaded column, the external thread of which is matched and connected with the internal thread of the guide hole at the top of the umbrella-shaped exhaust cover; The center shaft is coaxially welded to the bottom of the threaded column; The spiral guide vane is welded along the outer wall of the central axis at a spiral angle of 15°-25°, and the pitch is 2-4 times the height of the spiral vane. The spiral guide vane is located in the rotating tube.

[0011] The present invention also provides a γ-butyrolactone distillation treatment process of the above-mentioned equipment, comprising the steps of: S1. Vacuum start: The pressure in the distillation column is gradually reduced from atmospheric pressure to 10-50kPa by a vacuum pump within 30 minutes, with a pressure fluctuation of ≤±1kPa. The vacuum system is controlled by a top cooler and a second cooler; S2. Staged heating: Using reboiler steam gradient heating, the distillation tower temperature is controlled at 90-100°C, the distillation tower temperature gradient is controlled at 3-5°C / theoretical plate, and the heating rate is ≤2°C / min; S3. Dynamic reflux: Based on the online gas chromatograph monitoring of the light component content, the reflux ratio of cooler 1 is adjusted between 1.5 and 2.5. Cooler 2 sends the wastewater containing light components to the hazardous waste storage tank for treatment; S4. Side-line extraction: When the purity of the liquid phase on the 7th tray is ≥99.8%, the extraction is started, with the extraction flow rate to feed ratio of 1:1.5-1:2. The product is cooled and then enters the finished product tank; S5. High boiling treatment: When the concentration of heavy components in the distillation tower is ≥85%, switch to the high boiling tank and recover γ-butyrolactone through secondary distillation in a thin film evaporator.

[0012] Furthermore, a control model with a negative correlation between vacuum degree and heating temperature is established. The temperature of the distillation tower increases by 5-8°C for every 1 kPa decrease in vacuum degree, and a PID controller is used to compensate for pressure fluctuations in real time to reduce energy consumption. The distillation tower uses a bubble cap component to enhance gas-liquid mass transfer.

[0013] Furthermore, a cascade energy recovery system is implemented: a) Cooler 1 and Cooler 2 use a series water circuit. The cooling water first enters the top cooler 1 and then serves as the water inlet to Cooler 2. The water temperature difference is controlled to be ≤15℃; b) The waste heat from the top of the tower is used to preheat the raw materials through a plate heat exchanger, raising the crude feed temperature by 20-30°C; c) Process wastewater and vacuum pump accumulated liquid are collected in hazardous waste storage tanks and then professionally treated.

[0014] Compared with the existing technology, one or more of the above technical solutions have the following beneficial effects: 1. This invention utilizes the synergistic effect of a rotating vapor distribution component and a cyclonic structure. The spiral guide vanes generate vortex airflow that drives the L-shaped tube to rotate at high speed, creating pulsed exhaust and microbubble group diffusion. Compared to traditional bubble towers, this increases the gas-liquid contact area, and the dynamic permeation effect improves the mass transfer coefficient. 2. The liquid layer adjustment system of the present invention achieves dynamic adjustment of the overflow weir height by 20-50% through the fixed connection of the air pressure balance plate and the lifting plate. When the system pressure fluctuates by ±5kPa, the liquid layer thickness is automatically adjusted, effectively suppressing mist entrainment, reducing the amount of light components carried over from the tower top, and ensuring product purity. 3. The vacuum system of the present invention significantly reduces the boiling point of γ-butyrolactone, reduces the steam consumption of the reboiler, and the cascade energy recovery system preheats the crude product by utilizing waste heat, thereby reducing overall energy consumption. 4. The combined design of the reinforcement component and the spiral linkage mechanism of the present invention significantly reduces the bubble diameter and destroys the boundary layer, which not only increases the gas-liquid contact area but also increases the gas-liquid contact time. 5. The combination of the hazardous waste storage tank and thin-film evaporator improves heavy component recovery and reduces process wastewater discharge. Microbubble technology reduces heavy component carryover, lowering hazardous waste treatment costs and meeting green chemical production standards.

[0015] In summary, the present invention, through structural innovation and process optimization, achieves a dual reduction in energy and material consumption while ensuring high product purity. It is highly efficient, intelligent, and environmentally friendly, providing an advanced solution for the distillation production of γ-butyrolactone.

[0016] It is to be understood that the foregoing general description and the following detailed description are exemplary and explanatory only and are not restrictive of the invention. BRIEF DESCRIPTION OF THE DRAWINGS

[0017] The accompanying drawings, which constitute a part of the present invention, are used to provide a further understanding of the present invention. The exemplary embodiments of the present invention and their descriptions are used to explain the present invention and do not constitute improper limitations on the present invention.

[0018] Figure 1 It is a schematic diagram of the overall structure of the present invention; Figure 2 It is a structural schematic diagram of a distillation tower of the present invention; Figure 3 It is a schematic structural diagram of the tower tray and bubble cap assembly of the present invention; Figure 4 is a schematic cross-sectional structural diagram of a blister assembly of the present invention; Figure 5 yes Figure 4 Schematic diagram of the local structure at A; Figure 6 It is a schematic diagram of the structure of the vent pipe and the closed guide groove of the present invention; Figure 7 It is a structural schematic diagram of the reinforcement component of the present invention.

[0019] In the picture: 1-Feeding pump; 11-Cooler 1; 12-Cooler 2; 13-Hazardous waste storage tank; 14-Finished product storage tank; 15-Vacuum pump; 2-Distillation tower; 21-Tower shell; 22-Tower tray; 23-Overflow weir; 24-Downcomer; 241-Guide chute; 3-Bubble cap assembly; 31-Ventilation pipe; 311-Ventilation channel; 32-Rotary vapor distribution member; 321-Rotary pipe; 3211-Closed guide groove; 3212-Protruding ring; 3213 -Lower thrust bearing; 3214-Upper thrust bearing; 3215-Threaded cover; 322-Umbrella-shaped exhaust hood; 323-L-shaped pipe; 33-Cyclone structure; 331-Spiral guide vane; 332-Center axis; 333-Threaded column; 334-Assembly hole; 4-Liquid layer adjustment system; 41-Lifting plate; 42-Air pressure balance plate; 421-Connecting pipe; 43-Linkage slider; 44-Spring group; 5-Reinforcement component; 51-Through hole; 52-Guide block. DETAILED DESCRIPTION

[0020] In order to enable those skilled in the art to better understand the present invention, the following will clearly and completely describe the technical solutions in the embodiments of the present invention in conjunction with the drawings 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 in the present invention, all other embodiments obtained by ordinary technicians in this field without making creative efforts should fall within the scope of protection of this application.

[0021] See also Figure 1-Figure 7 The present invention provides a single-tower distillation device for γ-butyrolactone, comprising a feeding pump 1, a distillation tower 2, a cooler 11, a cooler 2 12, a hazardous waste storage tank 13, a finished product storage tank 14, and a vacuum pump 15. The distillation tower 2 comprises a tower shell 21, the interior of the tower shell 21 is uniformly provided with tower plates 22 along the height direction, an overflow weir 23 is provided on one side of the tower plate 22, and a downcomer 24 is connected below the overflow weir 23; A bubble assembly 3 is evenly distributed above the tower plate 22, and the bubble assembly 3 includes a ventilation pipe 31, a rotating steam distribution component 32 and a cyclone structure 33; the bottom end of the ventilation pipe 31 is fixed to the top of the tower plate 22 and forms a ventilation channel 311 that penetrates the tower plate 22, and the top height of the ventilation pipe 31 is higher than the highest point of the overflow weir 23; the rotating steam distribution component 32 includes a rotating tube 321 rotatably arranged in the ventilation channel 311, an umbrella-shaped exhaust cover 322 connected to the top of the rotating tube 321, and a plurality of L-shaped tubes 323 evenly distributed along the outer periphery of the umbrella-shaped exhaust cover 322, and the bottom end of each L-shaped tube 323 extends below the liquid surface of the tower plate 22; the cyclone structure 33 is composed of a spiral guide plate 331 arranged on the inner wall of the rotating tube 321, and the spiral guide plate 331 is at a preset angle with the axis of the rotating tube 321, and can drive the rotating tube 321 to rotate through the flow of steam.

[0022] When high-temperature steam enters distillation tower 2, it ascends along vent tube 31 and passes through internal spiral guide vanes 331, forming a vortex flow. This vortex flow plays two key roles: first, it drives the rotation of rotating tube 321; second, it evenly distributes the airflow around the tube wall through centrifugal force. Combined with the radially distributed L-shaped tubes 323 around its periphery, this creates a pulsed exhaust effect during rotation. The unique design of L-shaped tube 323 ensures that its tip is always immersed 10-15mm in the liquid layer. Rotation produces two enhanced mass transfer effects: first, it forms a cluster of microbubbles, increasing the gas-liquid contact area; second, it generates localized vortices in the liquid layer (generated by the rotation of L-shaped tube 323), disrupting the liquid film boundary layer and transforming the static contact of traditional bubble towers into dynamic penetration.

[0023] Furthermore, during the above process, as the steam flow rate increases, the speed of rotating tube 321 driven by spiral guide vanes 331 increases, and the jet velocity of L-shaped tube 323 increases simultaneously. Due to the increased centrifugal force, the diameter of steam bubbles entering the liquid layer is destroyed and reduced during the rotation of L-shaped tube 323, effectively reducing the kinetic energy of the rising bubbles, extending the vapor's residence time in the liquid phase, and improving the distillation separation effect. The vacuum pump 15 maintains the system pressure in distillation column 2 at 5-10 kPa, lowering the boiling point of γ-butyrolactone from 204°C (at atmospheric pressure) to 85-90°C, thereby reducing overall energy consumption.

[0024] In this embodiment, a liquid layer adjustment system 4 is provided below the tray 22, comprising: A lifting plate 41 that slides with the side wall of the overflow weir 23, and the vertical movement range of the lifting plate 41 covers 20%-50% of the height of the overflow weir 23; A pressure balancing plate 42 is provided parallel to and below the tray 22. The pressure balancing plate 42 is in air communication with the ventilation channel 311 via a connecting pipe 421, and the top end of the connecting pipe 421 is embedded in the ventilation channel 311. The downcomer plate 24 is provided with a guide slot 241 , and the pressure balance plate 42 is fixedly connected to the lifting plate 41 via a linkage slider 43 extending into the guide slot 241 ; A pressure adaptive spring group 44 is installed between the air pressure balance plate 42 and the tower plate 22.

[0025] Based on the above-mentioned arrangement, when the air pressure in the distillation tower 2 fluctuates, the air pressure acts on the air pressure balance plate 42, and the air pressure drives the air pressure balance plate 42 to move in the vertical direction. When the air pressure balance plate 42 moves in the vertical direction, the linkage slider 43 embedded in the guide slot 241 can drive the lifting plate 41 to undergo vertical displacement, so that the lifting plate 41 covers 20%-50% of the height of the overflow weir 23, and the effective height of the overflow weir 23 is adjusted in real time. For example, when the air pressure increases, the air pressure balance plate 42 moves upward → the linkage slider 43 slides along the guide slot 241 → the lifting plate 41 rises synchronously, thereby increasing the thickness of the liquid layer, promoting more liquid phase to fully contact with the gas phase, and suppressing the mist entrainment phenomenon caused by high-speed airflow (that is, the gas flow rate is too fast, causing it to impact upward violently, easily bringing the liquid directly to the upper tower plate or the top of the tower, causing product contamination, which is actually called mist entrainment phenomenon). Conversely, when the air pressure decreases, the air pressure balance plate 42 moves downward rapidly under the reset thrust of the spring group 44, and the downward action of the lifting plate 41 directly reduces the effective liquid layer thickness on the tower plate 22. This adjustment process produces a dual effect: on the one hand, it reduces the flow resistance of the liquid phase, and on the other hand, by reducing the gas-liquid contact space, it promotes the accelerated sedimentation and separation of the heavy components (high-boiling point substances) under the action of gravity, thereby maintaining the phase equilibrium state of the distillation process.

[0026] In this embodiment, the bottom ends of all L-shaped tubes 323 are connected to an annular reinforcement member 5. Multiple groups of diffusion holes 51 are evenly distributed on the top of the reinforcement member 5. The axes of the diffusion holes 51 form a downward angle of 10°-30° with the horizontal, and the spacing between adjacent diffusion holes 51 is 3-5 times the hole diameter. A gap is reserved between the inner wall of the reinforcement member 5 and the outer wall of the vent tube 31 to form a dynamic airflow channel. The rigid frame of the annular reinforcement member 5 connects the bottom ends of adjacent L-shaped tubes 323 as a whole, improving radial vibration resistance and effectively suppressing the amplitude of the end of the L-shaped tube 323. When the bubbles come into contact with the annular reinforcement member 5 in the liquid layer, the diffusion holes 51 shear off the initial bubbles, reducing their diameter and effectively reducing their rising kinetic energy, thereby extending the vapor's residence time in the liquid phase.

[0027] In this embodiment, the reinforcing member 5 is connected to the vent pipe 31 via a spiral linkage mechanism, which includes: An inclined closed guide groove 3211 is provided on the outer wall of the vent pipe 31; A guide block 52 fixed to the inner wall of the reinforcing member 5 is embedded in the inclined closed guide groove 3211 and slides along the track of the inclined closed guide groove 3211; When the L-shaped tube 323 rotates along with the rotating tube 321 , the guide block 52 moves along the inclined closed guide groove 3211 , driving the reinforcing member 5 to rotate synchronously and rise and fall periodically along the axial direction of the vent tube 31 .

[0028] During use, the inclined closed guide groove 3211 on the outer wall of the vent tube 31 and the guide block 52 on the inner wall of the reinforcement component 5 form a sliding pair. When the L-shaped tube 323 rotates with the rotating tube 321, the guide block 52 slides along the guide groove track; the reinforcement component 5 forms a periodic rise and fall, and its periodic rise and fall induces local turbulence in the liquid layer. On the one hand, the vortex flow generated by the rising vibration flushes the high-viscosity material deposited on the edge of the diffusion hole 51, preventing the diffusion hole 51 from being blocked; on the other hand, the bubbles encounter a periodic shear force field during the rising process, and are further divided into microbubbles, thereby increasing the gas-liquid mass transfer area.

[0029] In this embodiment, a convex ring 3212 protruding outward is provided in the middle of the rotating tube 321, and a threaded cover 3215 is slidably provided on the rotating tube 321 above the convex ring 3212. The threaded cover 3215 is threadedly engaged with the top of the ventilation tube 31. A lower thrust bearing 3213 is provided between the bottom of the convex ring 3212 and the top of the ventilation tube 31, and an upper thrust bearing 3214 is provided between the top of the convex ring 3212 and the top of the threaded cover 3215.

[0030] The lower thrust bearing 3213 beneath the raised ring 3212 bears the weight of the rotating tube 321 and the upward force of the steam. The upper thrust bearing 3214, through the preload of the threaded cap 3215, balances the axial vibration of the rotating tube 321 during high-speed rotation. When the threaded cap 3215 is screwed onto the top of the vent tube 31, its bottom presses against the top surface of the raised ring 3212. The upper and lower thrust bearings 3213 break down the axial load on the rotating tube 321 into bidirectional pressure, while simultaneously maintaining radial free rotation of the rotating tube 321. This design ensures that the rotational torque generated by the spiral guide vane 331 is stably transmitted to the L-shaped tube 323 assembly, preventing axial play and extending the equipment's continuous operation cycle.

[0031] In this embodiment, the center of the top of the umbrella-shaped exhaust cover 322 is provided with an assembly hole 334; the cyclone structure 33 includes: The external thread of the threaded column 333 is matched with the internal thread of the assembly hole 334 at the top of the umbrella-shaped exhaust cover 322; The central shaft 332 is coaxially welded to the bottom of the threaded column 333; The spiral guide vane 331 is welded along the outer wall of the central axis 332 at a spiral angle of 15°-25°, and the pitch is 2-4 times the height of the spiral vane. The spiral guide vane 331 is located in the rotating tube 321.

[0032] The present invention also provides a γ-butyrolactone distillation treatment process of the above-mentioned equipment, comprising the steps of: S1 vacuum start: by the vacuum pump 15 within 30 minutes the pressure in the distillation column 2 is gradually reduced from atmospheric pressure to 10-50kPa, pressure fluctuations ≤ ± 1kPa, the vacuum system and the top cooler 11, cooler 12 linkage control; S2. Staged heating: Using reboiler steam gradient heating, the distillation tower temperature is controlled at 90-100°C, the temperature gradient of distillation tower 2 is controlled at 3-5°C / theoretical plate, and the heating rate is ≤2°C / min; S3 dynamic reflux: Based on the online gas chromatograph monitoring light component content, adjust the cooler 11 reflux ratio between 1.5-2.5, cooler II 12 will contain light component wastewater into the hazardous waste storage tank 13 for treatment; S4. Side-line extraction: When the liquid purity on the seventh tray 22 is ≥99.8%, the extraction is started, with a ratio of extraction flow to feed of 1:1.5-1:2. The product is cooled and then enters the finished product tank; S5. High boiling treatment: When the concentration of heavy components in the distillation tower is ≥85%, switch to the high boiling tank and recover γ-butyrolactone through secondary distillation in a thin film evaporator.

[0033] In this embodiment, a control model with negative correlation between vacuum degree and heating temperature is established. When the vacuum degree decreases by 1 kPa, the temperature of the distillation tower increases by 5-8°C, and the pressure fluctuation is compensated in real time by a PID controller to reduce energy consumption. The distillation tower 2 adopts a bubble assembly 3 to enhance gas-liquid mass transfer.

[0034] In this embodiment, a cascade energy recovery system is implemented: a) Cooler 11 and cooler 2 12 use a series water circuit. The cooling water first enters the top cooler 11 and then serves as the inlet water for cooler 2 12. The water temperature difference is controlled to be ≤15℃; b) The waste heat from the top of the tower is used to preheat the raw materials through a plate heat exchanger, raising the crude feed temperature by 20-30°C; c) Process wastewater and accumulated liquid from the vacuum pump 15 are collected in the hazardous waste storage tank 13 and then processed professionally.

[0035] The above description is only a preferred specific embodiment of the present invention, but the scope of protection of the present invention is not limited thereto. Any technician familiar with the technical field, within the technical scope disclosed by the present invention, who makes equivalent replacements or changes based on the technical solution and inventive concept of the present invention, should be covered by the scope of protection of the present invention.

Claims

1. A single-tower distillation apparatus for γ-butyrolactone, comprising a feed pump, a distillation tower, a first cooler, a second cooler, a hazardous waste storage tank, a finished product storage tank, and a vacuum pump. The distillation tower comprises a tower shell, wherein the tower shell has trays uniformly arranged along the height direction. An overflow weir is provided on one side of the tray, and a downcomer is connected below the overflow weir. It is characterized by: A bubble cap assembly is evenly distributed above the tower plate, and the bubble cap assembly includes a ventilation pipe, a rotating steam distribution component and a cyclone structure; the bottom end of the ventilation pipe is fixed to the top of the tower plate and forms a ventilation channel running through the tower plate, and the top end of the ventilation pipe is higher than the highest point of the overflow weir; the rotating steam distribution component includes a rotating tube rotatably arranged in the ventilation channel, an umbrella-shaped exhaust cover connected to the top of the rotating tube, and a plurality of L-shaped tubes evenly distributed along the outer periphery of the umbrella-shaped exhaust cover, and the bottom end of each L-shaped tube extends below the liquid level of the tower plate; the cyclone structure is composed of a spiral guide plate arranged on the inner wall of the rotating tube, and the spiral guide plate is at a preset angle to the axis of the rotating tube, which can drive the rotating tube to rotate through the flow of steam.

2. The single-tower distillation equipment for γ-butyrolactone according to claim 1, characterized in that: A liquid layer adjustment system is provided below the tray, comprising: The lifting plate slides with the side wall of the overflow weir, and its vertical movement range covers 20%-50% of the overflow weir height; An air pressure balance plate is arranged parallel to the bottom of the tower plate, the air pressure balance plate is connected to the air path of the ventilation channel through a connecting pipe, and the top end of the connecting pipe is embedded in the ventilation channel; The surface of the downcomer is provided with a guide chute, and the air pressure balance plate is fixedly connected to the lifting plate via a linkage slider extending into the guide chute; A pressure adaptive spring group is installed between the air pressure balance plate and the tower plate.

3. The single-tower distillation equipment for γ-butyrolactone according to claim 1, characterized in that: The bottom ends of all L-shaped tubes are connected to an annular reinforcement member, and multiple groups of diffusion holes are evenly opened on the reinforcement member, and the axis of the diffusion hole forms a downward inclination angle of 10°-30° with the horizontal direction, and the spacing between adjacent diffusion holes is 3-5 times the aperture; a gap is reserved between the inner wall of the reinforcement member and the outer wall of the ventilation pipe to form a dynamic airflow channel.

4. The single-tower distillation equipment for γ-butyrolactone according to claim 3, characterized in that: The reinforcing member is connected to the vent pipe via a spiral linkage mechanism, which includes: An inclined closed guide groove is provided on the outer wall of the vent pipe; A guide block fixed to the inner wall of the reinforcement member, the guide block being embedded in the inclined closed guide groove and sliding along the track of the inclined closed guide groove; When the L-shaped tube rotates with the rotating tube, the guide block moves along the inclined closed guide groove, driving the reinforcement component to rotate synchronously and rise and fall periodically along the axial direction of the ventilation tube.

5. The single-tower distillation equipment for γ-butyrolactone according to claim 1, characterized in that: A convex ring protruding outward is provided in the middle of the rotating tube, and a threaded cover is slidably provided on the rotating tube above the convex ring. The threaded cover is threadedly matched with the top of the vent pipe. A lower thrust bearing is provided between the bottom of the convex ring and the top of the vent pipe, and an upper thrust bearing is provided between the top of the convex ring and the top of the threaded cover.

6. The single-tower distillation equipment for γ-butyrolactone according to claim 2, characterized in that: The center of the top of the umbrella-shaped exhaust cover is provided with a guide hole; the cyclone structure includes: A threaded column, the external thread of which is matched and connected with the internal thread of the guide hole at the top of the umbrella-shaped exhaust cover; The center shaft is coaxially welded to the bottom of the threaded column; The spiral guide vane is welded along the outer wall of the central axis at a spiral angle of 15°-25°, and the pitch is 2-4 times the height of the spiral vane. The spiral guide vane is located in the rotating tube.

7. A γ-butyrolactone distillation process based on the equipment according to any one of claims 1 to 6, characterized in that: Including steps: S1. Vacuum start: The pressure in the distillation column is gradually reduced from atmospheric pressure to 10-50kPa by a vacuum pump within 30 minutes, with a pressure fluctuation of ≤±1kPa. The vacuum system is controlled by a top cooler and a second cooler; S2. Staged heating: Using reboiler steam gradient heating, the distillation tower temperature is controlled at 90-100°C, the distillation tower temperature gradient is controlled at 3-5°C / theoretical plate, and the heating rate is ≤2°C / min; S3. Dynamic reflux: Based on the online gas chromatograph monitoring of the light component content, the reflux ratio of cooler 1 is adjusted between 1.5 and 2.

5. Cooler 2 sends the wastewater containing light components to the hazardous waste storage tank for treatment; S4. Side-line extraction: When the purity of the liquid phase on the 7th tray is ≥99.8%, the extraction is started, with the extraction flow rate to feed ratio of 1:1.5-1:

2. The product is cooled and then enters the finished product tank; S5. High boiling treatment: When the concentration of heavy components in the distillation tower is ≥85%, switch to the high boiling tank and recover γ-butyrolactone through secondary distillation in a thin film evaporator.

8. The γ-butyrolactone distillation process according to claim 7, wherein: A control model with negative correlation between vacuum degree and heating temperature is established. When the vacuum degree decreases by 1 kPa, the temperature of the distillation tower increases by 5-8°C. The pressure fluctuation is compensated in real time by a PID controller to reduce energy consumption. The distillation tower adopts a bubble cap component to enhance gas-liquid mass transfer.

9. The γ-butyrolactone distillation process according to claim 7, wherein: Implementing a cascade energy recovery system: a) Cooler 1 and Cooler 2 use a series water circuit. The cooling water first enters the top cooler 1 and then serves as the water inlet to Cooler 2. The water temperature difference is controlled to be ≤15℃; b) The waste heat from the top of the tower is used to preheat the raw materials through a plate heat exchanger, raising the crude feed temperature by 20-30°C; c) Process wastewater and vacuum pump accumulated liquid are collected in hazardous waste storage tanks and then professionally treated.

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