Low-temperature rectification purification device for food-grade liquid carbon dioxide

Abstract

The invention discloses a low-temperature rectification purification device for food-grade liquid carbon dioxide, which comprises a rectification tower body, an inner container single body is arranged in the rectification tower body, the inner container single body is composed of a straight cylinder inner container and a conical opening inner container which are welded in sequence from head to tail, and a spraying structure shaped like a Chinese character'feng 'is arranged in the rectification tower body above the inner container single body. A liquid storage tank is arranged on one side of the rectifying tower body, a pump liquid lifting unit is installed at the liquid outlet end of the liquid storage tank, and the liquid outlet end of the pump liquid lifting unit is connected with the liquid inlet end of the spraying structure shaped like the Chinese character'feng '. According to the invention, feed gas is ensured to reach an ideal temperature before entering the rectifying tower, the purification efficiency of the rectifying tower is improved, the feed gas can be efficiently preheated before entering the rectifying tower by adopting a coiled multi-point gas inlet preheating structure, the purpose of split-flow gas inlet is realized, and meanwhile, the preheated gas has higher activity, so that the purification effect of the rectifying tower is improved. Contact and reaction with liquid in the tower are easier, so that the rectification process is accelerated.

Description

Technical Field

[0001] The invention relates to the technical field of liquid carbon dioxide, in particular to a low-temperature distillation and purification device for food-grade liquid carbon dioxide. Background Art

[0002] A distillation tower is a chemical equipment used to purify liquid carbon dioxide. It is mainly composed of a tower body, a tower top, a tower bottom, a reboiler, a condenser and a control system. Its structural principle is based on the different boiling points of liquid mixtures. During the distillation process, the raw liquid is heated and evaporated in the reboiler to form steam. During the rising process, the steam encounters the liquid on the tower plate and conducts mass transfer and heat transfer. Due to the different boiling points of the liquid mixture, the light components (such as CO 2 ) are easier to evaporate, while heavy components (such as impurities) are difficult to evaporate. In this way, the concentration of light components in the vapor gradually increases, while the concentration of heavy components in the liquid gradually increases. At the top of the tower, the vapor is condensed into liquid, and part of the liquid is sent back to the bottom of the tower as reflux liquid to make up for the loss of liquid at the bottom of the tower. The other part of the liquid is output as product. At the bottom of the tower, the liquid is heated and evaporated by the reboiler to form steam, which continues to rise. This process is circulated continuously until the predetermined purity is reached. The distillation tower achieves liquid CO through this continuous cycle process. 2 For purification, at present, when the raw gas (the components of the raw gas are 95-99% carbon dioxide, 0.4-2% water, 0.1-2% alcohol, 0.1-1% hydrocarbon, temperature: 10-40°C, pressure: 0.1-0.2M) enters the distillation tower, the raw gas is directly sent in through the air inlet pipe on the outer wall of the distillation tower. In this process, the raw gas is not preheated, and the raw gas needs to reach the bottom of the distillation tower before it can be heated. Since the raw gas is not preheated before entering the distillation tower, the distillation tower needs to consume more energy to increase the temperature of the raw gas at the beginning, and the distillation tower cannot achieve the best separation effect at the beginning. Summary of the invention

[0003] The object of the present invention is to provide a low-temperature distillation and purification device for food-grade liquid carbon dioxide. Electric heating modules and inner liner monomers for distilling and purifying liquid carbon dioxide and gaseous carbon dioxide are successively added to the inner wall of the distillation tower body. When the carbon dioxide gas is fed into the inner liner monomer, a coiled multi-point air inlet preheating structure is used to feed the carbon dioxide gas into the inner liner monomer to solve the problems raised in the above-mentioned background technology.

[0004] To achieve the above object, the present invention provides the following technical solution: a low-temperature distillation and purification device for food-grade liquid carbon dioxide, comprising: A distillation tower body, wherein an inner liner monomer is installed inside the distillation tower body, and the inner liner monomer is composed of a straight inner liner and a tapered inner liner welded in sequence at the head and tail ends; a "F"-shaped spray structure is installed inside the distillation tower body above the inner liner monomer; a liquid storage tank is arranged on one side of the distillation tower body, and a pumping liquid lifting unit is installed at the liquid outlet end of the liquid storage tank, and the liquid outlet end of the pumping liquid lifting unit is connected to the liquid inlet end of the "F"-shaped spray structure; and tower plates with alternating opening directions are installed at equal intervals inside the straight inner liner; An electric heating module, wherein the electric heating module is arranged on the inner wall of the distillation tower body, and a coiled multi-point air inlet preheating structure for preheating the raw gas is installed at one end of the surface of the straight cylinder inner tank; A condenser is installed on an outer wall of one side of a distillation tower body, an air inlet end of the condenser is equipped with an exhaust pipe for interconnecting with the exhaust end of the distillation tower body, a PLC control panel is installed on one side of the surface of the liquid storage tank, and an output end of the PLC control panel is electrically connected to a pump liquid lifting unit, a coiled multi-point air inlet preheating structure, and an input end of an electric heating module.

[0005] Preferably, the pump liquid lifting unit includes a second delivery pump installed on one side of the liquid storage tank, a lifting pipe is installed at the liquid outlet end of the second delivery pump, and the liquid inlet end of the second delivery pump is connected to the liquid outlet end of the liquid storage tank.

[0006] Preferably, a liquid discharge pipe is installed on one side outer wall of the distillation tower body, and a reflux pipe for interconnecting with the liquid inlet end of the liquid storage tank is installed at one end of the liquid discharge pipe.

[0007] Preferably, the "F"-shaped spray structure comprises a "F"-shaped diverter pipe installed at one end inside the distillation tower body and a plurality of nozzles installed on the lower surface of the "F"-shaped diverter pipe, and one end of the "F"-shaped diverter pipe is interconnected with one end of the riser.

[0008] Preferably, a packing plate is fixed inside the distillation tower body above the "F"-shaped spray structure, and the upper surface of the packing plate is filled with molecular sieve.

[0009] Preferably, the electric heating module includes a hollow heat-conducting liner fixed on the inner wall of the distillation tower body and an electric heating wire installed inside the hollow heat-conducting liner, and the input end of the electric heating wire is electrically connected to the output end of the PLC control panel.

[0010] Preferably, the coiled multi-point air intake preheating structure includes a hollow annular air intake shell installed on the outer peripheral surface of the straight cylindrical inner liner, and a plurality of spiral coil riser pipes installed at the bottom end of the hollow annular air intake shell, wherein one end of the spiral coil riser away from the hollow annular air intake shell extends to the interior of the straight cylindrical inner liner, and the spiral coil riser is located in the gap between the straight cylindrical inner liner and the hollow heat-conducting liner.

[0011] Preferably, an electromagnetic air intake valve is installed on one side of the bottom end of the hollow annular air intake shell.

[0012] Preferably, the condenser includes an arc-shaped seat fixed on the outer wall of the distillation tower body, an external cooling tube installed on the outer wall of the arc-shaped seat, and a straight condenser installed inside the external cooling tube, an air inlet joint is installed on one side of the top end of the straight condenser, the top end of the air inlet joint passes through the outside of the external cooling tube and is interconnected with the bottom end of the exhaust pipe, a liquid outlet pipe is installed at the bottom end of the straight condenser, the bottom end of the liquid outlet pipe passes through the outside of the external cooling tube, and a flow guide pipe is installed on one side of the back side of the external cooling tube.

[0013] Preferably, a first delivery pump is installed on an outer wall of one side of the external cooling tube, and a liquid outlet end of the first delivery pump is connected to a liquid inlet end of the external cooling tube.

[0014] Compared with the prior art, the beneficial effects of the present invention are as follows: the low-temperature distillation and purification device for food-grade liquid carbon dioxide can efficiently preheat the raw gas by adding an electric heating module, and the electric heating module can be adjusted according to actual production needs to ensure that the raw gas reaches an ideal temperature before entering the distillation tower, thereby improving the purification efficiency of the distillation tower, and the use of a coiled multi-point air inlet preheating structure can enable the raw gas to be efficiently preheated before entering the distillation tower, and achieve the purpose of diverting the air intake, and at the same time, the preheated gas has higher activity and is easier to contact and react with the liquid in the tower, thereby accelerating the distillation process, improving the purification efficiency of the distillation tower and product quality, and obtaining a higher purity liquid carbon dioxide product. BRIEF DESCRIPTION OF THE DRAWINGS

[0015] Figure 1 It is a schematic diagram of the main structure of the present invention; Figure 2 It is a schematic diagram of the main cross-sectional structure of the present invention; Figure 3 The three-dimensional structure of the present invention is shown in FIG. Figure 1 ; Figure 4 The three-dimensional structure of the present invention is shown in FIG. Figure 2 ; Figure 5 It is a schematic diagram of a three-dimensional cross-sectional structure of the present invention; Figure 6 It is a schematic diagram of the three-dimensional cross-sectional structure of a distillation tower body according to the second embodiment of the present invention; Figure 7 It is a schematic diagram of a three-dimensional cross-sectional structure of a condenser according to the third embodiment of the present invention; Figure 8 It is a schematic diagram of the three-dimensional structure of embodiment 3 of the present invention.

[0016] In the figure: 1. distillation tower body; 101. drain pipe; 2. liquid storage tank; 3. pump liquid lifting unit; 4. coiled multi-point air intake preheating structure; 401. hollow annular air intake shell; 402. spiral coil riser; 5. electromagnetic air intake valve; 6. exhaust pipe; 7. condenser; 701. arc seat; 702. external cooling pipe; 703. guide pipe; 704. straight condenser; 7041. air intake joint; 705. liquid outlet pipe; 706. first delivery pump; 8. straight cylinder liner; 9. cone-mouth liner; 10. "F"-shaped spray structure; 1001. "F"-shaped diverter pipe; 1002. nozzle; 11. packing plate; 12. tower plate; 13. electric heating module; 1301. hollow heat-conducting liner; 1302. electric heating wire; 14. PLC control panel. DETAILED DESCRIPTION

[0017] The technical solutions in the embodiments of the present invention will be described clearly and completely below in conjunction with the accompanying drawings in the embodiments of the present invention. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0018] Embodiment 1, by Figures 1 to 5 The present invention comprises a distillation tower body 1, wherein an inner liner monomer is installed inside the distillation tower body 1, and the inner liner monomer is composed of a straight inner liner 8 and a tapered inner liner 9 welded in sequence at the head and tail ends, and a "F"-shaped spray structure 10 is installed inside the distillation tower body 1 above the inner liner monomer, a liquid storage tank 2 is arranged on one side of the distillation tower body 1, and a pumping liquid lifting unit 3 is installed at the liquid outlet end of the liquid storage tank 2, and the liquid outlet end of the pumping liquid lifting unit 3 is connected to the liquid inlet end of the "F"-shaped spray structure 10, and tower plates 12 with opening directions alternating with each other are installed at equal intervals inside the straight inner liner 8; The electric heating module 13 is arranged on the inner wall of the distillation tower body 1, and a coiled multi-point air inlet preheating structure 4 for preheating the raw gas is installed at one end of the surface of the straight cylinder liner 8; Condenser 7, condenser 7 is installed on one side outer wall of the distillation tower body 1, an exhaust pipe 6 for interconnecting with the exhaust end of the distillation tower body 1 is installed at the air inlet end of the condenser 7, a PLC control panel 14 is installed on one side of the surface of the liquid storage tank 2, and the output end of the PLC control panel 14 is electrically connected to the pump liquid lifting unit 3, the coiled multi-point air inlet preheating structure 4, and the input end of the electric heating module 13; The pump liquid lifting unit 3 includes a second delivery pump installed on one side of the liquid storage tank 2, a lifting pipe is installed at the liquid outlet end of the second delivery pump, and the liquid inlet end of the second delivery pump is connected to the liquid outlet end of the liquid storage tank 2. A discharge pipe 101 is installed on the outer wall of one side of the distillation tower body 1, and a reflux pipe for connecting to the liquid inlet end of the liquid storage tank 2 is installed at one end of the discharge pipe 101. The staff turns on the second delivery pump in the pump liquid lifting unit 3, and the second delivery pump generates negative pressure suction and delivers the liquid carbon dioxide in the liquid storage tank 2 to the "F"-shaped spray structure 10 through the lifting pipe, so that the liquid carbon dioxide is evenly sprayed to the inside of the straight cylinder liner 8 and the cone-mouth liner 9 through the "F"-shaped spray structure 10, thereby realizing the output of liquid carbon dioxide; The liquid discharge pipe 101 is connected to the liquid inlet end of the liquid storage tank 2 through a pipeline, so that the straight inner tank 8, the liquid discharge pipe 101, the liquid storage tank 2, and the pump liquid lifting unit 3 form a circulation pipeline for the undistilled and purified liquid carbon dioxide raw material; The "F"-shaped spray structure 10 includes a "F"-shaped shunt pipe 1001 installed at one end inside the distillation tower body 1 and a plurality of nozzles 1002 installed on the lower surface of the "F"-shaped shunt pipe 1001. One end of the "F"-shaped shunt pipe 1001 is interconnected with one end of the riser. A packing plate 11 is fixed inside the distillation tower body 1 above the "F"-shaped spray structure 10. The upper surface of the packing plate 11 is filled with a molecular sieve. The molecular sieve has a strong adsorption capacity and can effectively adsorb impurities in gas and liquid to improve the purity of the product. In the distillation tower, the molecular sieve can adsorb moisture, oxygen and a small amount of other impurities in the carbon dioxide gas, thereby improving the purity of the liquid carbon dioxide after distillation. The molecular sieve has excellent high temperature resistance, can maintain its structure and adsorption performance at higher temperatures, and can operate at relatively high temperatures. Liquid carbon dioxide is fed into the "F"-shaped shunt pipe 1001 and sprayed out from the nozzle 1002 at the bottom of the "F"-shaped shunt pipe 1001, and the liquid carbon dioxide is evenly sprayed into the straight inner liner 8 and the tapered inner liner 9, thereby increasing the contact area between the liquid carbon dioxide and the gaseous carbon dioxide and improving the distillation and purification efficiency; Liquid carbon dioxide flows from top to bottom through each layer of tower plates 12 by gravity and is discharged from the bottom of the distillation tower body 1. A flowing liquid layer of a certain thickness is maintained on each layer of tower plates 12. Driven by the pressure difference, the gas rises from the bottom of the tower upward through the liquid layers on each tower plate 12 in turn to the top of the tower and is discharged. The gas and liquid contact each plate in the tower to exchange mass and heat.

[0019] Embodiment 2, based on embodiment 1, Figure 6The electric heating module 13 includes a hollow heat-conducting liner 1301 fixed on the inner wall of the distillation tower body 1 and an electric heating wire 1302 installed inside the hollow heat-conducting liner 1301. The input end of the electric heating wire 1302 is electrically connected to the output end of the PLC control panel 14. The electric heating wire 1302 is directly located inside the distillation tower body 1. The heat generated by the electric heating wire 1302 can be indirectly transferred to the gas and liquid in the tower, thereby improving the temperature control accuracy. The coiled multi-point air intake preheating structure 4 includes a hollow annular air intake shell 401 installed on the outer peripheral surface of the straight cylinder inner liner 8, and a plurality of spiral coil risers 402 connected and installed at the bottom end of the hollow annular air intake shell 401. The spiral coil riser 402 extends to the interior of the straight cylinder inner liner 8 from one end of the hollow annular air intake shell 401. The spiral coil riser 402 is located in the gap between the straight cylinder inner liner 8 and the hollow heat-conducting liner 1301. An electromagnetic air intake valve 5 is installed on one side of the bottom end of the hollow annular air intake shell 401. The raw gas is sucked into the coiled multi-point air intake preheating structure 4. The electromagnetic air intake valve 5 can control the inflow of gas to ensure the stability of gas pressure and flow. At the same time, the response speed of the electromagnetic air intake valve 5 is very fast, and the inflow of gas can be quickly opened or closed as needed, thereby improving the response speed and control accuracy of the equipment; The electric heating wire 1302 in the hollow heat-conducting tube 1301 is turned on through the PLC control panel 14 to heat the hollow heat-conducting tube 1301 and the straight-cylinder inner tube 8. The raw gas connected to the electromagnetic air intake valve 5 is diverted through the hollow annular air intake shell 401 into each spiral riser 402. The spiral riser 402 surrounds the outside of the straight-cylinder inner tube 8, so that the raw gas in the spiral riser 402 can be heated, thereby achieving the purpose of preheating. Finally, the heated raw gas flows upward from the bottom of the straight-cylinder inner tube 8.

[0020] Embodiment 3, based on embodiment 1, Figure 7 and Figure 8 It is given that the condenser 7 includes an arc-shaped seat 701 fixed on the outer wall of the distillation tower body 1, an external cooling pipe 702 installed on the outer wall of the arc-shaped seat 701, and a straight condenser 704 installed inside the external cooling pipe 702, an air inlet joint 7041 is installed on one side of the top of the straight condenser 704, the top of the air inlet joint 7041 penetrates to the outside of the external cooling pipe 702 and is interconnected with the bottom end of the exhaust pipe 6, a liquid outlet pipe 705 is installed at the bottom end of the straight condenser 704, the bottom end of the liquid outlet pipe 705 penetrates to the outside of the external cooling pipe 702, a guide pipe 703 is installed on one side of the back of the external cooling pipe 702, a first delivery pump 706 is installed on the outer wall of one side of the external cooling pipe 702, the liquid outlet end of the first delivery pump 706 is interconnected with the liquid inlet end of the external cooling pipe 702, the external cooling pipe 702 is used to form a cooling water channel, and the straight condenser 704 is used to condense the gas; The staff connects the liquid inlet of the first delivery pump 706 to the coolant supply end, so that the coolant is delivered to the external cooling tube 702 and surrounds the outside of the straight condenser 704. The purified carbon dioxide gas at the top of the distillation tower body 1 enters the straight condenser 704 through the air inlet connector 7041, and exchanges heat with the low-temperature straight condenser 704 to condense into liquid carbon dioxide. At this time, the liquid carbon dioxide is discharged through the liquid outlet pipe 705 and collected.

[0021] When the embodiment of the present application is used, the drain pipe 101 is first connected to the liquid inlet end of the liquid storage tank 2 through a pipeline, so that the straight cylinder liner 8, the drain pipe 101, the liquid storage tank 2, and the pump liquid lifting unit 3 form a circulation pipeline for the undistilled and purified liquid carbon dioxide raw material, and the electromagnetic air intake valve 5 is connected to the supply end of the external carbon dioxide gas to be purified, and the raw gas is sucked into the coiled multi-point air intake preheating structure 4. The electromagnetic air intake valve 5 can control the inflow of the gas to ensure the stability of the gas pressure and flow rate. Then the staff turns on the electric heating module 1 through the PLC control panel 14. 3. When the pump liquid lifting unit 3 is working, the electric heating module 13 heats the inner liner monomer formed by the straight inner liner 8 and the tapered inner liner 9. Since the coiled multi-point air inlet preheating structure 4 is between the inner liner monomer and the electric heating module 13, the raw gas is preheated through the coiled multi-point air inlet preheating structure 4, so that the gas is fully in contact with the heat source for heat exchange before entering the distillation tower body 1 and the inner liner monomer, thereby increasing the temperature of the gas and preparing for the distillation process. The preheated raw gas is evenly diffused into the inner liner monomer through the coiled multi-point air inlet preheating structure 4. In this process The pump liquid lifting unit 3 lifts the liquid carbon dioxide in the liquid storage tank 2 to the top of the distillation tower body 1 and enters the interior of the "F"-shaped spray structure 10. The "F"-shaped spray structure 10 evenly sprays the liquid carbon dioxide on the top of the tower. The gaseous carbon dioxide countercurrently contacts with the liquid carbon dioxide flowing down the top of the tower to transfer heat and mass. Due to the different boiling points of the liquid mixture, the light component is easier to evaporate, while the heavy component is difficult to evaporate. In this way, the concentration of the light component in the vapor gradually increases, while the concentration of the heavy component in the liquid gradually increases, that is, the concentration of the heavy component in the liquid phase gradually increases as the tower height decreases. The concentration of gaseous carbon dioxide increases gradually and continues to rise through the exhaust pipe 6 into the interior of the condenser 7. In this process, a number of tower plates 12 allow the gas and liquid to contact multiple times, thereby improving the separation effect, and the gas-liquid two-phase flow directions on each tower plate 12 are opposite, so that the carbon dioxide component is continuously enriched, and the purity of the gas at the top of the distillation tower is improved. In the condenser 7, the gaseous carbon dioxide is liquefied and stored in the connected external purification tank, and the raw gas is preheated, distilled, separated, condensed, stored and recycled, thereby achieving efficient purification of carbon dioxide.

[0022] It should be noted that, in this article, relational terms such as first and second, etc. are only used to distinguish one entity or operation from another entity or operation, and do not necessarily require or imply any such actual relationship or order between these entities or operations. Moreover, the terms "include", "comprise" or any other variants thereof are intended to cover non-exclusive inclusion, so that a process, method, article or device including a series of elements includes not only those elements, but also other elements not explicitly listed, or also includes elements inherent to such process, method, article or device.

[0023] Although embodiments of the present invention have been shown and described, it will be appreciated by those skilled in the art that various changes, modifications, substitutions and variations may be made to the embodiments without departing from the principles and spirit of the present invention, and that the scope of the present invention is defined by the appended claims and their equivalents.

Claims

1. A low temperature distillation and purification device for food grade liquid carbon dioxide, characterized in that: include: A distillation tower body (1), wherein an inner liner monomer is installed inside the distillation tower body (1), and the inner liner monomer consists of a straight inner liner (8) and a tapered inner liner (9) welded in sequence at the head and tail ends; a "F"-shaped spray structure (10) is installed inside the distillation tower body (1) above the inner liner monomer; a liquid storage tank (2) is provided on one side of the distillation tower body (1), and a pumping liquid lifting unit (3) is installed at the liquid outlet end of the liquid storage tank (2); the liquid outlet end of the pumping liquid lifting unit (3) is connected to the liquid inlet end of the "F"-shaped spray structure (10); and tower plates (12) with opening directions alternating with each other are installed at equal intervals inside the straight inner liner (8); An electric heating module (13), the electric heating module (13) being arranged on the inner wall of the distillation tower body (1), and a coiled multi-point air inlet preheating structure (4) for preheating the raw material gas being installed at one end of the surface of the straight cylindrical inner liner (8); A condenser (7), the condenser (7) being mounted on an outer wall of one side of a distillation tower body (1), an exhaust pipe (6) for interconnecting with an exhaust end of the distillation tower body (1) being mounted on an air inlet end of the condenser (7), a PLC control panel (14) being mounted on one side of a surface of the liquid storage tank (2), an output end of the PLC control panel (14) being electrically connected to an input end of a pump liquid lifting unit (3), a coiled multi-point air inlet preheating structure (4), and an electric heating module (13).

2. The low temperature distillation and purification device for food grade liquid carbon dioxide according to claim 1, characterized in that: The pump liquid lifting unit (3) comprises a second delivery pump installed on one side of the liquid storage tank (2), a lifting pipe being installed at the liquid outlet end of the second delivery pump, and a liquid inlet end of the second delivery pump being connected to a liquid outlet end of the liquid storage tank (2).

3. The low temperature distillation and purification device for food grade liquid carbon dioxide according to claim 1, characterized in that: A liquid discharge pipe (101) is installed on one side outer wall of the distillation tower body (1), and a reflux pipe for interconnecting with the liquid inlet end of the liquid storage tank (2) is installed at one end of the liquid discharge pipe (101).

4. The low temperature distillation and purification device for food grade liquid carbon dioxide according to claim 2, characterized in that: The "F"-shaped spray structure (10) comprises a "F"-shaped diverter pipe (1001) installed at one end inside the distillation tower body (1) and a plurality of spray heads (1002) installed on the lower surface of the "F"-shaped diverter pipe (1001), wherein one end of the "F"-shaped diverter pipe (1001) is connected to one end of the riser.

5. The low temperature distillation and purification device for food grade liquid carbon dioxide according to claim 1, characterized in that: A packing plate (11) is fixed inside the distillation tower body (1) above the "F"-shaped spray structure (10), and the upper surface of the packing plate (11) is filled with a molecular sieve.

6. The low temperature distillation and purification device for food grade liquid carbon dioxide according to claim 1, characterized in that: The electric heating module (13) comprises a hollow heat-conducting liner (1301) fixed on the inner wall of the distillation tower body (1) and an electric heating wire (1302) installed inside the hollow heat-conducting liner (1301), wherein the input end of the electric heating wire (1302) is electrically connected to the output end of the PLC control panel (14).

7. The low-temperature distillation and purification device for food-grade liquid carbon dioxide according to claim 6, characterized in that: The coiled multi-point air intake preheating structure (4) comprises a hollow annular air intake shell (401) installed on the outer peripheral surface of a straight cylindrical inner liner (8), and a plurality of spiral coil riser pipes (402) installed at the bottom end of the hollow annular air intake shell (401), wherein one end of the spiral coil riser pipe (402) away from the hollow annular air intake shell (401) extends to the interior of the straight cylindrical inner liner (8), and the spiral coil riser pipe (402) is located in a gap between the straight cylindrical inner liner (8) and the hollow heat-conducting liner (1301).

8. The low-temperature distillation and purification device for food-grade liquid carbon dioxide according to claim 7, characterized in that: An electromagnetic air intake valve (5) is installed on one side of the bottom end of the hollow annular air intake shell (401).

9. The low temperature distillation and purification device for food grade liquid carbon dioxide according to claim 1, characterized in that: The condenser (7) comprises an arc-shaped seat (701) fixed on the outer wall of the distillation tower body (1), an external cooling pipe (702) installed on the outer wall of the arc-shaped seat (701), and a straight condenser (704) installed inside the external cooling pipe (702); an air inlet joint (7041) is installed on one side of the top end of the straight condenser (704); the top end of the air inlet joint (7041) penetrates to the outside of the external cooling pipe (702) and is interconnected with the bottom end of the exhaust pipe (6); a liquid outlet pipe (705) is installed at the bottom end of the straight condenser (704); the bottom end of the liquid outlet pipe (705) penetrates to the outside of the external cooling pipe (702); and a flow guide pipe (703) is installed on one side of the back side of the external cooling pipe (702).

10. The low temperature distillation and purification device for food grade liquid carbon dioxide according to claim 9, characterized in that: A first delivery pump (706) is installed on an outer wall of one side of the external cooling tube (702), and a liquid outlet end of the first delivery pump (706) is connected to a liquid inlet end of the external cooling tube (702).

Images