A molecular sieve-based deep drying apparatus and method for high-purity liquid carbon dioxide.

Abstract

This invention relates to the field of drying equipment technology, and discloses a molecular sieve deep drying device and method for high-purity liquid carbon dioxide. The device includes a dual-tower dryer support frame, a drying tower assembly, a molecular sieve filter layer, and a regeneration exhaust port. The drying tower assembly is fixedly connected to the top of the dual-tower dryer support frame. The molecular sieve filter layer is disposed inside the drying tower assembly, and the regeneration exhaust port is disposed at the bottom of the drying tower assembly. Detection and alarm components are symmetrically arranged inside the drying tower assembly. By optimizing the elastic support and monitoring structure of the molecular sieve filter layer, the invention solves the problems of traditional devices being unable to monitor the working status of the molecular sieve in real time, and the easy reduction in drying efficiency and product purity due to molecular sieve expansion and pulverization or blockage. The elastic support structure composed of the filter plug, pressure grid, detection spring, and support grid in the device can adapt to the volume expansion of the molecular sieve filter layer during the drying process, preventing the molecular sieve from pulverizing and breaking due to rigid compression.

Description

Technical Field

[0001] This invention relates to the field of drying equipment, specifically to a molecular sieve deep drying device and method for high-purity liquid carbon dioxide. Background Technology

[0002] The dual-tower adsorption dryer is a core piece of equipment in the industrial field for the dehydration and purification of high-purity liquid carbon dioxide. It achieves continuous production by alternating drying and regeneration operations in two towers.

[0003] Existing molecular sieve beds in most devices employ rigid support structures, which cannot adapt to the expansion and compression of the molecular sieves. This easily leads to the sieves being crushed and broken, significantly shortening their service life and increasing the costs of consumable replacement and equipment maintenance. Furthermore, existing devices lack real-time monitoring of the molecular sieve's operating status. Operators typically rely on timed switching or manual inspections, which cannot promptly detect abnormalities such as expansion, pulverization, or blockage of the molecular sieves. This can easily cause a continuous deterioration in drying efficiency, substandard product purity, and affect the continuous and stable production of high-purity liquid carbon dioxide. Regarding dual-tower switching control, existing equipment mostly uses manual or timed switching modes, resulting in low levels of automation and intelligence. This means it cannot dynamically adjust the switching timing according to the actual operating conditions of the molecular sieves, easily leading to energy waste or drying failure. It also suffers from response lag and large operational errors, which can easily cause production interruptions.

[0004] Regarding energy conservation and safety, existing dual-tower dryers often directly vent the regenerated exhaust gas, wasting waste heat resources. Furthermore, the condensate carried by the dryer easily freezes and clogs pipelines under low-temperature conditions, leading to freezing and blockage failures. Conventional gas-liquid separation structures have low separation efficiency and cannot remove liquid water, easily causing pipeline corrosion and freezing, shortening equipment lifespan and resulting in non-compliant exhaust emissions, failing to meet green production requirements. In terms of media flow and sealing performance, an unreasonable liquid distribution structure design can easily cause liquid carbon dioxide deviation, leading to low drying efficiency; an imperfect sealing structure can easily cause media short-circuit leakage, wasting materials, interfering with differential pressure monitoring signals, affecting the accuracy of molecular sieve status monitoring, and further reducing the stability and reliability of the unit's operation.

[0005] Therefore, there is a need to provide a molecular sieve deep drying device and method for high-purity liquid carbon dioxide, which aims to solve the above problems. Summary of the Invention

[0006] To address the shortcomings of existing technologies, the present invention aims to provide a molecular sieve deep drying device and method for high-purity liquid carbon dioxide.

[0007] To achieve the above objectives, the present invention provides the following technical solution: a molecular sieve deep drying device for high-purity liquid carbon dioxide, comprising a dual-tower dryer support frame, a drying tower assembly, a molecular sieve filter layer, and a regeneration exhaust gas outlet. The drying tower assembly is fixedly connected to the top of the dual-tower dryer support frame, the molecular sieve filter layer is disposed inside the drying tower assembly, the regeneration exhaust gas outlet is disposed at the bottom of the drying tower assembly, and detection alarm components are symmetrically arranged inside the drying tower assembly.

[0008] The detection alarm assembly includes two filter discs, which are disposed inside the drying tower assembly. Each of the two filter discs is fixedly connected to a clamping grid on opposite sides. On the side of the clamping grids away from the filter discs, detection springs are fixedly connected in a ring at equal intervals. A support grid is fixedly connected to the side of the detection springs away from the clamping grids. A sealing ring is installed on the side of the support grids away from the detection springs. Pressure tapping pipes are symmetrically arranged in the middle of the drying tower assembly, and a pressure tapping sealing plug is provided at the connection between the pressure tapping pipes and the drying tower assembly.

[0009] Preferably, the detection alarm component includes a control box, which is fixedly connected to the drying tower assembly. The control box contains a differential pressure transmitter, an early warning trigger switch, and a time delay controller. An alarm is installed on the top of the control box, and solenoid valves are symmetrically arranged at the bottom of the drying tower assembly.

[0010] Preferably, a tail gas preheating and separation component is provided below the drying tower group. The tail gas preheating and separation component includes a support plate, which is located below the drying tower group. A tubular heat exchanger is fixedly connected to the top of the support plate. A three-way pipe is installed on the top of the tubular heat exchanger. A gas-liquid separator is connected to the bottom outlet of the tubular heat exchanger. A flow guide baffle is fixedly connected inside the gas-liquid separator. A liquid passage pipe is connected to the bottom of the gas-liquid separator. A liquid collection box is snapped into the bottom of the liquid passage pipe.

[0011] Preferably, the exhaust gas preheating and separation assembly includes a liquid feed pipe, one end of which is fixedly connected to the bottom inlet of the drying tower assembly, and the other end of which is connected to the outlet of the tubular heat exchanger. The inlet of the tubular heat exchanger is connected to a liquid carbon dioxide inlet, and the end of the liquid carbon dioxide inlet away from the tubular heat exchanger is fixedly connected to the support frame of the double-tower dryer.

[0012] Preferably, the molecular sieve filter layer is disposed between two filter plugs, the two supporting grid plates are symmetrically fixedly connected to the inner wall of the drying tower assembly, the detection end of the pressure tapping pipe is disposed between the pressing grid plate and the supporting grid plate, and the output end of the pressure tapping pipe extends to the control box and is connected to the differential pressure transmitter.

[0013] Preferably, the ends of both pressure taps furthest from the pressure grid are connected to the differential pressure transmitter.

[0014] Preferably, the side of the three-way pipe furthest from the tubular heat exchanger is connected to the regeneration exhaust port.

[0015] A method for deep drying high-purity liquid carbon dioxide using molecular sieves, wherein the operation of the molecular sieve deep drying device includes the following steps:

[0016] Step 1: Low-temperature liquid carbon dioxide enters the tube side of the tubular heat exchanger through the liquid carbon dioxide inlet, and exchanges heat with the shell side regeneration tail gas for preheating. The preheated liquid carbon dioxide is then sent to the bottom of the drying tower group through the liquid feed pipe.

[0017] Step 2: Liquid carbon dioxide passes through the molecular sieve filter layer from bottom to top for deep dehydration and drying. During the drying process, the filter plug, the clamping grid plate, and the detection spring expand with the expansion of the molecular sieve and generate elastic displacement. The pressure tapping tube collects the chamber pressure between the clamping grid plate and the support grid plate in real time.

[0018] Step 3: The pressure tapping tube transmits the pressure signal to the differential pressure transmitter. The differential pressure transmitter monitors the working status of the molecular sieve filter layer in real time, and the delay controller filters and delays the differential pressure signal.

[0019] Step 4: The exhaust gas generated during the regeneration process of the drying tower group is discharged from the regeneration exhaust gas outlet and flows into the shell side of the tubular heat exchanger through the three-way pipe. After heat exchange and cooling, it enters the gas-liquid separator for gas-liquid separation. The separated condensate flows into the liquid collection box through the liquid pipe.

[0020] Step 5: When the pressure difference exceeds the set threshold, the early warning trigger switch activates the alarm and controls the corresponding solenoid valve to complete the automatic switching between the two towers, ensuring the continuous and stable operation of the drying process.

[0021] Preferably, the gas-liquid separator adopts an eccentric air inlet structure in conjunction with internal guide baffles to achieve swirling separation, and the outer wall of the liquid passage pipe is equipped with an anti-freeze heat tracing structure to prevent condensate from freezing and clogging under low-temperature conditions.

[0022] Preferably, the internal support grid plates of the drying tower group are symmetrically fixed, and the sealing ring and the pressure tapping sealing plug form a double seal to avoid medium short-circuit leakage and pressure signal distortion.

[0023] The present invention provides a molecular sieve-based deep drying device and method for high-purity liquid carbon dioxide. Compared with the prior art, the advantages of the present invention are:

[0024] By optimizing the elastic support and monitoring structure of the molecular sieve filter layer, the problems of traditional devices being unable to monitor the working status of the molecular sieve in real time, easily leading to decreased drying efficiency and substandard product purity due to molecular sieve expansion and pulverization or blockage are solved. The elastic support structure composed of the filter plug, pressure grid, detection spring, and support grid can adapt to the volume expansion of the molecular sieve filter layer during the drying process, avoiding pulverization and damage to the molecular sieve due to rigid compression, extending the service life of the molecular sieve, and reducing the cost of equipment consumable replacement. At the same time, the pressure tapping pipe and differential pressure transmitter work together to achieve real-time monitoring of the working status of the molecular sieve, which can promptly capture abnormal signals of the molecular sieve, providing maintenance basis for operators, avoiding the deterioration of drying effect due to failure to detect molecular sieve failure in time, and ensuring the stable production of high-purity liquid carbon dioxide.

[0025] By employing a differential pressure early warning and intelligent tower switching control structure, the shortcomings of conventional dual-tower dryers on the market—relying on manual switching and experiencing delayed early warning responses—are overcome, thereby improving the automation and continuity of the unit's operation. The delay controller filters the differential pressure signal, avoiding false alarms caused by instantaneous pressure fluctuations and improving warning accuracy. The early warning trigger switch synchronously links the alarm and solenoid valve, promptly reminding operators to perform equipment maintenance and enabling automatic switching between the two towers without shutdown. This prevents interruptions in the entire drying process due to the failure of a single tower molecular sieve, ensuring production continuity.

[0026] The design of the waste heat recovery and gas-liquid separation structure for regenerated exhaust gas achieves efficient energy utilization and safe pipeline protection. The tubular heat exchanger uses the waste heat of the regenerated exhaust gas to preheat the low-temperature liquid carbon dioxide, recovering and utilizing the waste heat generated during the regeneration process, reducing the energy consumption of subsequent drying processes, and achieving practical energy saving and consumption reduction. At the same time, the gas-liquid separator, in conjunction with the guide baffle, can separate the condensate in the regenerated exhaust gas, achieving gas-liquid separation of the regenerated exhaust gas and improving the cleanliness of the exhaust gas emissions.

[0027] The self-regulating electric heating tape that comes with the liquid flow pipe addresses the problem of liquid water freezing and clogging the pipes under low-temperature conditions. It ensures the continuous unobstructed drainage path, avoids equipment downtime due to pipe blockage, and guarantees the stability and safety of equipment operation. At the same time, the liquid collection box provides centralized temporary storage for condensate, making it convenient for operators to discharge and treat it regularly.

[0028] The porous structure of the filter disc enables uniform distribution of liquid carbon dioxide, preventing media deviation and ensuring full contact between the liquid carbon dioxide and the molecular sieve filter layer, thereby improving drying contact efficiency and ensuring uniform and stable drying effect. The sealing design of the sealing ring and the pressure tapping sealing plug prevents media short-circuit leakage, ensuring both the sealing and stability of the drying process and preventing pressure signal leakage from affecting the accuracy of differential pressure detection, thus improving the accuracy of molecular sieve monitoring. Attached Figure Description

[0029] Figure 1 This is a schematic diagram showing the overall positional relationship of the device in this invention;

[0030] Figure 2 This is a cross-sectional view of the overall device in this invention;

[0031] Figure 3 For the present invention Figure 2 Enlarged view of the structure at point A in the middle;

[0032] Figure 4 For the present invention Figure 3 Enlarged view of the structure at point B in the middle;

[0033] Figure 5 This is a schematic diagram showing the positional relationship between the filter disc, the pressing grid plate, the supporting grid plate, and the detection spring in this invention;

[0034] Figure 6 For the present invention Figure 5 Enlarged view of the structure at point C;

[0035] Figure 7 This is a schematic diagram showing the positional relationship between the drying tower group, control box, early warning trigger switch, and delay controller in this invention;

[0036] Figure 8 This is a schematic diagram showing the positional relationship between the tubular heat exchanger, gas-liquid separator, liquid inlet pipe, and liquid collection box in this invention.

[0037] Figure 9 This is a schematic diagram showing the positional relationship between the tubular heat exchanger, the liquid feed pipe, and the liquid carbon dioxide inlet in this invention.

[0038] Figure 10 This is a schematic diagram showing the positional relationship of the gas-liquid separator, the flow guide baffle, the liquid passage pipe, and the liquid collection box in this invention.

[0039] Reference numerals: 11. Support frame for the dual-tower dryer; 12. Drying tower assembly; 13. Molecular sieve filter layer; 14. Regeneration exhaust gas outlet;

[0040] The detection alarm assembly includes: 21. Filter plug disc; 22. Pressure plate; 23. Support plate; 24. Detection spring; 25. Sealing ring; 26. Pressure tapping tube; 27. Pressure tapping sealing plug; 28. Control box; 29. ​​Differential pressure transmitter; 210. Early warning trigger switch; 211. Delay controller; 212. Alarm; 213. Solenoid valve;

[0041] The exhaust gas preheating and separation assembly includes: 31, support plate; 32, tubular heat exchanger; 33, tee pipe; 34, gas-liquid separator; 35, flow guide baffle; 36, liquid passage pipe; 37, liquid collection box; 38, liquid feed pipe; 39, liquid carbon dioxide inlet. Detailed Implementation

[0042] To make the objectives, technical solutions, and advantages of the present invention clearer, the present invention will be further described in detail below with reference to the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are merely for explaining the present invention and are not intended to limit the present invention.

[0043] In the description of this invention, the terms “center,” “horizontal,” “up,” “down,” “left,” “right,” “vertical,” “horizontal,” “top,” “bottom,” “inner,” and “outer,” etc., indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings. They are only for the convenience of describing this invention and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation. Therefore, they should not be construed as limitations on this invention.

[0044] The specific implementation of the present invention will be described in detail below with reference to specific embodiments.

[0045] Example 1

[0046] like Figures 1 to 10 As shown, a molecular sieve deep drying device for high-purity liquid carbon dioxide includes a dual-tower dryer support frame 11, a drying tower group 12, a molecular sieve filter layer 13, and a regeneration exhaust gas outlet 14. The drying tower group 12 is fixedly connected to the top of the dual-tower dryer support frame 11. The molecular sieve filter layer 13 is disposed inside the drying tower group 12. The regeneration exhaust gas outlet 14 is disposed at the bottom of the drying tower group 12. Detection alarm components are symmetrically arranged inside the drying tower group 12.

[0047] The detection alarm assembly includes two filter discs 21, which are located inside the drying tower assembly 12. Each filter disc 21 is fixedly connected to a pressure grid plate 22 on opposite sides. On the side of the pressure grid plate 22 away from the filter disc 21, detection springs 24 are fixedly connected in a ring at equal intervals. On the side of the detection springs 24 away from the pressure grid plate 22, a support grid plate 23 is fixedly connected. On the side of the support grid plate 23 away from the detection springs 24, a sealing pressure ring 25 is installed. Pressure tapping pipes 26 are symmetrically arranged in the middle of the drying tower assembly 12. Pressure tapping sealing plugs 27 are provided at the connection between the pressure tapping pipes 26 and the drying tower assembly 12.

[0048] The detection alarm component includes a control box 28, which is fixedly connected to the drying tower assembly 12. Inside the control box 28 are a differential pressure transmitter 29, an early warning trigger switch 210, and a time delay controller 211. These components are all conventional industrial automatic control parts and belong to existing technology, so they will not be described in detail here. They are electrically connected. The time delay controller 211 is connected to both the differential pressure transmitter 29 and the early warning trigger switch 210, receiving the pressure signal transmitted by the differential pressure transmitter 29 and performing filtering and delay processing before triggering the early warning trigger switch 210 to execute a linkage action. An alarm 212 is installed on the top of the control box 28 and is electrically connected to the early warning trigger switch 210. Solenoid valves 213 are symmetrically arranged at the bottom of the drying tower assembly 12 and are electrically connected to the early warning trigger switch 210, directly controlled by the switch.

[0049] It should be noted that: the molecular sieve filter layer 13 is clamped between the two filter plugs 21, the two support grids 23 are symmetrically fixed to the inner wall of the drying tower assembly 12, the detection end of the pressure tapping pipe 26 is located between the clamping grid 22 and the support grid 23, and the output end of the pressure tapping pipe 26 extends to the control box 28 and is connected to the differential pressure transmitter 29 for accurate acquisition of chamber pressure signals; the ends of the two pressure tapping pipes 26 away from the clamping grid 22 are both connected to the differential pressure transmitter 29 to ensure stable transmission of pressure signals to the differential pressure transmitter 29.

[0050] Below the drying tower group 12, there is a tail gas preheating and separation component. The tail gas preheating and separation component includes a support plate 31, which is located below the drying tower group 12. A tubular heat exchanger 32 is fixedly connected to the top of the support plate 31. The tubular heat exchanger 32 is a conventional heat exchange device and belongs to the prior art, so it will not be described in detail here. A three-way pipe 33 is installed on the top of the tubular heat exchanger 32. A gas-liquid separator 34 is connected to the bottom outlet of the tubular heat exchanger 32. A flow guide baffle 35 is fixedly connected inside the gas-liquid separator 34. A liquid passage pipe 36 is connected to the bottom of the gas-liquid separator 34. A liquid collection box 37 is snapped into the bottom of the liquid passage pipe 36.

[0051] The exhaust gas preheating and separation assembly includes a liquid feed pipe 38. One end of the liquid feed pipe 38 is fixedly connected to the bottom liquid inlet of the drying tower group 12, and the other end of the liquid feed pipe 38 is connected to the liquid outlet of the tubular heat exchanger 32. The liquid inlet of the tubular heat exchanger 32 is connected to a liquid carbon dioxide inlet 39, and the end of the liquid carbon dioxide inlet 39 away from the tubular heat exchanger 32 is fixedly connected to the support frame 11 of the double tower dryer.

[0052] It should be noted that the side of the three-way pipe 33 away from the tubular heat exchanger 32 is connected to the regeneration tail gas discharge port 14, so as to realize the convergence and transportation of regeneration tail gas to the inside of the tubular heat exchanger 32. The bottom air inlet of the gas-liquid separator 34 is eccentrically set, which, together with the internal guide baffle 35, improves the gas-liquid separation efficiency. The outer wall of the liquid passage pipe 36 is equipped with a self-regulating electric heating tape, which is wrapped around the outer wall of the liquid passage pipe 36 and covered with an insulation cotton layer for protection, to prevent residual condensate in the pipe from freezing and blocking the pipe, and to ensure smooth drainage. The self-regulating electric heating tape and the matching insulation cotton are both mature industrial low-temperature heat tracing components, which are existing technologies and will not be described in detail here.

[0053] Example 2

[0054] A method for deep drying of high-purity liquid carbon dioxide using molecular sieves, comprising the following steps in operating the molecular sieve deep drying apparatus:

[0055] Step 1: Low-temperature liquid carbon dioxide enters the tube side of the tubular heat exchanger 32 through the liquid carbon dioxide inlet 39, and exchanges heat with the shell side regeneration tail gas for preheating. The preheated liquid carbon dioxide is then sent to the bottom of the drying tower group 12 through the liquid feed pipe 38.

[0056] Step 2: Liquid carbon dioxide passes through the molecular sieve filter layer 13 from bottom to top for deep dehydration and drying. During the drying process, the filter plug plate 21, the clamping grid plate 22, and the detection spring 24 expand with the molecular sieve and generate elastic displacement. The pressure tapping pipe 26 collects the chamber pressure between the clamping grid plate 22 and the supporting grid plate 23 in real time. The supporting grid plate 23 is symmetrically fixed inside the drying tower group 12. The sealing ring 25 and the pressure tapping sealing plug 27 form a double seal to avoid medium short-circuit leakage and pressure signal distortion.

[0057] Step 3: The pressure tap 26 transmits the pressure signal to the differential pressure transmitter 29. The differential pressure transmitter 29 monitors the working status of the molecular sieve filter layer 13 in real time. The delay controller 211 filters and delays the differential pressure signal.

[0058] Step 4: The exhaust gas generated in the regeneration process of the drying tower group 12 is discharged from the regeneration exhaust gas outlet 14 and flows into the shell side of the tubular heat exchanger 32 through the three-way pipe 33. After heat exchange and cooling, it enters the gas-liquid separator 34 for gas-liquid separation. The gas-liquid separator 34 adopts an eccentric air inlet structure and internal guide baffles 35 to achieve swirling separation. The outer wall of the liquid passage pipe 36 is equipped with an anti-freeze heat tracing structure to prevent the condensate from freezing and blocking under low temperature conditions. The separated condensate flows into the liquid collection box 37 through the liquid passage pipe 36.

[0059] Step 5: When the pressure difference exceeds the set threshold, the early warning trigger switch 210 outputs a signal to activate the alarm 212 and control the corresponding solenoid valve 213 to complete the automatic switching of the two towers and ensure the continuous and stable operation of the drying process.

[0060] Based on the above embodiments, the following is the complete working process and working principle of the above embodiments:

[0061] In the initial state, the molecular sieve filter layer 13 inside the drying tower group 12 is sandwiched between two sets of filter plugs 21. The outer side of the filter plug 21 is connected in sequence with a pressing grid plate 22, a detection spring 24 and a supporting grid plate 23. The supporting grid plate 23 is sealed and fixed to the inner wall of the drying tower group 12 by a sealing pressure ring 25, forming an elastic support structure.

[0062] Monitoring steps for molecular sieve filter layer 13:

[0063] When the drying tower group 12 is working, the low-temperature liquid carbon dioxide will flow from bottom to top through the molecular sieve filter layer 13. During the drying process, the volume of the molecular sieve will gradually expand. The filter plug 21 and the pressing grid plate 22 will be slightly displaced by the medium pressure and the expansion of the molecular sieve, which will then squeeze the detection spring 24, causing the chamber pressure between the pressing grid plate 22 and the supporting grid plate 23 to change.

[0064] The detection end of the pressure tapping tube 26 collects the chamber pressure between the upper and lower sets of clamping grid plates 22 and the support grid plate 23 respectively, and transmits the pressure signal to the differential pressure transmitter 29 inside the control box 28 to realize real-time monitoring of the working status of the molecular sieve filter layer 13.

[0065] By optimizing the elastic support and monitoring structure of the molecular sieve filter layer 13, the problems of traditional devices being unable to monitor the working status of the molecular sieve in real time, being prone to pulverization or blockage due to molecular sieve expansion leading to decreased drying efficiency and substandard product purity are solved. The elastic support structure composed of the filter plug plate 21, the pressing grid plate 22, the detection spring 24, and the supporting grid plate 23 can adapt to the volume expansion of the molecular sieve filter layer 13 during the drying process, avoiding pulverization and damage of the molecular sieve due to rigid compression, extending the service life of the molecular sieve, and reducing the cost of equipment consumable replacement. At the same time, the pressure tapping pipe 26 and the differential pressure transmitter 29 work together to achieve real-time monitoring of the working status of the molecular sieve, which can promptly capture abnormal signals of the molecular sieve, providing maintenance basis for operators, avoiding the deterioration of drying effect due to failure of molecular sieve failure in time, and ensuring the stable production of high-purity liquid carbon dioxide.

[0066] Differential pressure early warning and intelligent tower switching control steps:

[0067] The differential pressure transmitter 29 transmits the collected differential pressure signal to the delay controller 211. The delay controller 211 filters the instantaneous differential pressure fluctuation and triggers the warning trigger switch 210 only when the differential pressure continues to exceed the set threshold.

[0068] The warning trigger switch 210 simultaneously triggers two actions: first, the alarm 212 on the top of the control box 28 is activated, emitting an audible and visual alarm signal to remind the operator of the abnormality of the molecular sieve bed; second, a control signal is sent to the solenoid valve 213 at the bottom of the drying tower group 12 to close the liquid inlet passage of the current working tower and open the liquid inlet passage of the standby tower, so as to realize the automatic switching between the two towers without stopping the machine, to prevent the failed molecular sieve from continuing to participate in the drying operation, and to ensure the purity of the dried liquid carbon dioxide and the continuous operation of the device.

[0069] By employing a differential pressure early warning and intelligent tower switching control structure, the shortcomings of conventional dual-tower dryers on the market, such as reliance on manual switching and delayed early warning response, are overcome, thereby improving the automation and continuity of the unit's operation. The delay controller 211 filters the differential pressure signal, avoiding false alarms caused by instantaneous pressure fluctuations and improving warning accuracy. The early warning trigger switch 210 synchronously links the alarm 212 and solenoid valve 213, which not only promptly reminds operators to perform equipment maintenance but also enables automatic switching between the two towers without shutdown, preventing the entire drying process from being interrupted due to the failure of a single tower molecular sieve and ensuring production continuity.

[0070] Regenerated exhaust gas waste heat recovery and gas-liquid separation steps:

[0071] During the regeneration process, the regeneration exhaust gas carrying moisture and residual heat is discharged from the regeneration exhaust gas outlet 14 at the bottom of the drying tower group 12, and flows into the shell side of the tubular heat exchanger 32 through the three-way pipe 33. The low-temperature liquid carbon dioxide to be dried enters the tube side of the tubular heat exchanger 32 from the liquid carbon dioxide inlet 39, and indirectly exchanges heat with the high-temperature regeneration exhaust gas in the shell side. The residual heat of the regeneration exhaust gas is used to preheat the low-temperature feed, reducing the energy consumption of subsequent drying processes.

[0072] After heat exchange, the temperature of the regenerated exhaust gas decreases, and the moisture it carries condenses into liquid. Subsequently, the regenerated exhaust gas enters the gas-liquid separator 34 through the outlet end at the bottom of the tubular heat exchanger 32. Under the swirling action of the guide baffle 35 inside the gas-liquid separator 34, the liquid water is separated and settles to the bottom, and is collected in the liquid collection box 37 through the liquid pipe 36, thus achieving efficient gas-liquid separation of the regenerated exhaust gas.

[0073] The design of the waste heat recovery and gas-liquid separation structure for regenerated exhaust gas achieves efficient energy utilization and safe pipeline protection. The tubular heat exchanger 32 uses the waste heat of the regenerated exhaust gas to preheat the low-temperature liquid carbon dioxide, recovers and utilizes the waste heat generated during the regeneration process, reduces the energy consumption of the subsequent drying process, and achieves the practical effect of energy saving and consumption reduction. At the same time, the gas-liquid separator 34, in conjunction with the guide baffle 35, can separate the condensate in the regenerated exhaust gas, realize the gas-liquid separation of the regenerated exhaust gas, and improve the cleanliness of the exhaust gas emission.

[0074] Gas-liquid separation and drainage steps:

[0075] The gas-liquid separator 34 features an eccentric air inlet design at its bottom, coupled with internally staggered guide baffles 35, creating a swirling flow of the regeneration exhaust gas. This utilizes centrifugal force to enhance gas-liquid separation and improve liquid water removal efficiency. The separated liquid water settles along the inner wall of the separator to the bottom and is temporarily stored in a liquid collection box 37 via a liquid pipe 36 for periodic discharge. The outer wall of the liquid pipe 36 is fitted with a self-regulating heating cable to continuously provide heat under low-temperature conditions, preventing residual liquid water inside the pipe from freezing and clogging, ensuring smooth drainage and safe operation of the device.

[0076] The self-regulating electric heating tape that comes with the liquid pipe 36 addresses the problem of liquid water freezing and clogging the pipes under low-temperature conditions. It ensures the continuous unobstructed drainage path, avoids equipment shutdown due to pipe blockage, and guarantees the stability and safety of equipment operation. At the same time, the liquid collection box 37 provides centralized temporary storage for condensate, facilitating regular discharge and treatment by operators.

[0077] Drying medium flow steps:

[0078] The preheated liquid carbon dioxide is transported to the bottom inlet of the drying tower group 12 through the liquid feed pipe 38. It passes through the filter plug plate 21 and the molecular sieve filter layer 13 from bottom to top. During the flow process, the water is adsorbed and removed by the molecular sieve. The dried clean carbon dioxide is discharged from the top of the tower.

[0079] The porous structure of the filter plate 21 can distribute the liquid evenly, avoid media deviation, and improve the drying contact efficiency; the dual sealing design of the sealing ring 25 and the pressure tapping sealing plug 27 prevents media short-circuit leakage, ensures the sealing and stability of the drying process, and at the same time avoids pressure signal leakage from affecting the differential pressure detection accuracy.

[0080] The porous structure of the filter plug 21 enables uniform distribution of liquid carbon dioxide, avoids media deviation, and ensures full contact between the liquid carbon dioxide and the molecular sieve filter layer 13, thereby improving drying contact efficiency and ensuring uniform and stable drying effect. The sealing design of the sealing ring 25 and the pressure tapping sealing plug 27 avoids media short-circuit leakage, which not only ensures the sealing and stability of the drying process, but also avoids the impact of pressure signal leakage on the differential pressure detection accuracy, thus improving the accuracy of molecular sieve monitoring.

[0081] While several embodiments and examples of the present invention have been described for those skilled in the art, these embodiments and examples are provided as examples and are not intended to limit the scope of the invention. These new embodiments can be implemented in various other ways, and various omissions, substitutions, and modifications can be made without departing from the spirit of the invention. These embodiments and their variations are included within the scope and spirit of the invention, and are included within the scope of the invention as described in the claims and its equivalents.

[0082] Furthermore, it should be understood that although this specification describes embodiments, not every embodiment contains only one independent technical solution. This narrative style is merely for clarity. Those skilled in the art should consider the specification as a whole, and the technical solutions in each embodiment can also be appropriately combined to form other embodiments that can be understood by those skilled in the art.

Claims

1. A molecular sieve deep drying device for high-purity liquid carbon dioxide, comprising a dual-tower dryer support frame (11), a drying tower assembly (12), a molecular sieve filter layer (13), and a regeneration exhaust gas outlet (14), wherein the drying tower assembly (12) is fixedly connected to the top of the dual-tower dryer support frame (11), the molecular sieve filter layer (13) is disposed inside the drying tower assembly (12), and the regeneration exhaust gas outlet (14) is disposed at the bottom of the drying tower assembly (12), characterized in that, The drying tower group (12) is symmetrically equipped with detection alarm components inside; The detection alarm assembly includes two filter discs (21), which are located inside the drying tower assembly (12). Each of the two filter discs (21) is fixedly connected to a pressing grid plate (22) on opposite sides. On the side of the pressing grid plate (22) away from the filter discs (21), detection springs (24) are fixedly connected in a ring at equal intervals. On the side of the detection springs (24) away from the pressing grid plate (22), a support grid plate (23) is fixedly connected. On the side of the support grid plate (23) away from the detection springs (24), a sealing pressure ring (25) is installed. Pressure tapping pipes (26) are symmetrically arranged in the middle of the drying tower assembly (12), and a pressure tapping sealing plug (27) is provided at the connection between the pressure tapping pipe (26) and the drying tower assembly (12).

2. The molecular sieve deep drying device for high-purity liquid carbon dioxide according to claim 1, characterized in that, The detection alarm component includes a control box (28), which is fixedly connected to the drying tower group (12). The control box (28) is equipped with a differential pressure transmitter (29), an early warning trigger switch (210), and a delay controller (211). An alarm (212) is installed on the top of the control box (28), and solenoid valves (213) are symmetrically arranged at the bottom of the drying tower group (12).

3. The molecular sieve deep drying device for high-purity liquid carbon dioxide according to claim 1, characterized in that, Below the drying tower group (12) is a tail gas preheating and separation component. The tail gas preheating and separation component includes a support plate (31). The support plate (31) is located below the drying tower group (12). A tubular heat exchanger (32) is fixedly connected to the top of the support plate (31). A three-way pipe (33) is installed on the top of the tubular heat exchanger (32). A gas-liquid separator (34) is connected to the bottom outlet of the tubular heat exchanger (32). A flow guide baffle (35) is fixedly connected inside the gas-liquid separator (34). A liquid passage pipe (36) is connected to the bottom of the gas-liquid separator (34). A liquid collection box (37) is snapped into the bottom of the liquid passage pipe (36).

4. The molecular sieve deep drying device for high-purity liquid carbon dioxide according to claim 3, characterized in that, The exhaust gas preheating and separation assembly includes a liquid feed pipe (38), one end of which is fixedly connected to the bottom inlet of the drying tower assembly (12), and the other end of which is connected to the outlet of the tubular heat exchanger (32). The inlet of the tubular heat exchanger (32) is connected to a liquid carbon dioxide inlet (39), and the end of the liquid carbon dioxide inlet (39) away from the tubular heat exchanger (32) is fixedly connected to the support frame (11) of the double tower dryer.

5. The molecular sieve deep drying device for high-purity liquid carbon dioxide according to claim 1, characterized in that, The molecular sieve filter layer (13) is disposed between two filter plugs (21), and the two support grids (23) are symmetrically fixedly connected to the inner wall of the drying tower assembly (12). The detection end of the pressure tapping pipe (26) is disposed between the pressing grid (22) and the support grid (23), and the output end of the pressure tapping pipe (26) extends to the control box (28) and is connected to the differential pressure transmitter (29).

6. The molecular sieve deep drying device for high-purity liquid carbon dioxide according to claim 2, characterized in that, The ends of the two pressure taps (26) away from the pressure grid (22) are connected to the differential pressure transmitter (29).

7. The molecular sieve deep drying device for high-purity liquid carbon dioxide according to claim 4, characterized in that, The side of the three-way pipe (33) away from the tubular heat exchanger (32) is connected to the regeneration tail gas discharge port (14).

8. A method for deep drying of high-purity liquid carbon dioxide using molecular sieves, characterized in that, The molecular sieve deep drying device for high-purity liquid carbon dioxide as described in claim 7, wherein the operation method of the molecular sieve deep drying device includes the following steps: Step 1: Low-temperature liquid carbon dioxide enters the tube side of the tubular heat exchanger (32) through the liquid carbon dioxide inlet (39) and exchanges heat with the shell side regeneration tail gas for preheating. The preheated liquid carbon dioxide is then fed into the bottom of the drying tower group (12) through the liquid feed pipe (38). Step 2: Liquid carbon dioxide passes through the molecular sieve filter layer (13) from bottom to top for deep dehydration and drying. During the drying process, the filter plug (21), the clamping grid plate (22) and the detection spring (24) generate elastic displacement as the molecular sieve expands. The pressure tapping tube (26) collects the chamber pressure between the clamping grid plate (22) and the support grid plate (23) in real time. Step 3: The pressure tap (26) transmits the pressure signal to the differential pressure transmitter (29). The differential pressure transmitter (29) monitors the working status of the molecular sieve filter layer (13) in real time. The delay controller (211) filters and delays the differential pressure signal. Step 4: The exhaust gas generated by the regeneration process of the drying tower group (12) is discharged from the regeneration exhaust gas outlet (14), and flows into the shell side of the tubular heat exchanger (32) through the three-way pipe (33). After heat exchange and cooling, it enters the gas-liquid separator (34) for gas-liquid separation. The separated condensate flows into the liquid collection box (37) through the liquid pipe (36). Step 5: When the pressure difference exceeds the set threshold, the early warning trigger switch (210) activates the alarm (212) and controls the corresponding solenoid valve (213) to complete the automatic switching of the two towers and ensure the continuous and stable operation of the drying process.

9. The method for deep drying of high-purity liquid carbon dioxide using molecular sieves according to claim 8, characterized in that, The gas-liquid separator (34) adopts an eccentric air inlet structure and internal guide baffles (35) to achieve swirling separation. The outer wall of the liquid pipe (36) is equipped with an antifreeze heat tracing structure to prevent condensate from freezing and blocking under low temperature conditions.

10. The method for deep drying of high-purity liquid carbon dioxide using molecular sieves according to claim 8, characterized in that, The internal support grid (23) of the drying tower group (12) is symmetrically fixed, and the sealing pressure ring (25) and the pressure tapping sealing plug (27) form a double seal to avoid medium short-circuit leakage and pressure signal distortion.

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