Low-temperature reactor low-temperature liquid nitrogen recyclable system and process

Abstract

The application relates to the technical field of low-temperature chemical gas separation and liquefaction equipment, and discloses a low-temperature liquid nitrogen recyclable system and process in a low-temperature reactor, which comprises a rotary cold storage distribution mechanism, a tube condenser, a double-layer adsorption tower mechanism, a low-temperature liquefaction cold box and a compression regenerative mechanism. A servo drive motor drives the cold storage runner to continuously rotate through a planetary gear reducer. The runner is divided into multiple cold storage cavities filled with aluminum cold storage balls by fan-shaped partition plates. A rotary distribution valve is controlled and switched by an independent valve drive motor according to an exhaust temperature signal. The valve core arc-shaped flow guide channel distributes the exhaust to a cold charge area or a cold release area. The sealing arc plate and the end face partition plate jointly divide three functional areas. The cold storage cavity liquid discharge groove is discharged through the end plate liquid leakage hole. The cold energy is continuously transferred through mechanical rotation, the exhaust temperature step fluctuation is smoothed, the solvent vapor is pre-condensed and removed, the temperature field of the downstream low-temperature cold box is stable, and the liquid nitrogen output is continuous.

Description

Technical Field

[0001] This invention belongs to the technical field of low-temperature chemical gas separation and liquefaction equipment, specifically relating to a low-temperature liquid nitrogen recycling system and process in a low-temperature reactor. Background Technology

[0002] In intermittent cryogenic reaction processes in industries such as pharmaceuticals, fine chemicals, and new materials, liquid nitrogen serves as a cold source to provide a low-temperature environment for the reaction. The cryogenic nitrogen gas discharged from the reactor is purified, reliquefied, and recycled. Existing circulation systems are matched according to the reactor's steady-state exhaust conditions, employing a single-stage condenser and a single adsorption bed for purification. Some systems have a static cold storage tank installed between the reactor exhaust pipeline and the condenser, with valves switching the cold storage tank between cold storage and cold release states.

[0003] However, during the periodic batch switching of the intermittent cryogenic reactor, the temperature of the discharged nitrogen and the concentration of solvent vapor undergo a step-like dramatic change. During the heating and discharging stage, the exhaust temperature jumps from -100 to -140°C in the isothermal reaction stage to -40 to -70°C, and the solvent vapor concentration surges from a low level to 3000 to 6000 ppm; during the cooling and filling stage, the exhaust temperature drops again to -140 to -160°C.

[0004] Existing static cold storage tank solutions rely on valve switching to alternate between cold storage and cold release. Valve switching is a discrete operation, and there are temperature overshoots and flow fluctuations at the moment of switching, which cannot achieve continuous transfer of cold energy. At the same time, cold storage and cold release cannot be carried out simultaneously. Cold energy cannot be utilized in time during the cold storage stage, and the temperature buffer capacity drops sharply after the cold energy is exhausted during the cold release stage. This results in insufficient cooling capacity of the single-stage condenser matched according to steady-state conditions, a sharp drop in condensation efficiency, and a large amount of solvent vapor penetrating into the adsorption bed, which greatly shortens the penetration time. At the same time, the temperature step fluctuation is transmitted to the reliquefaction cold box, causing temperature field oscillations, resulting in interruption of liquid nitrogen production and shutdown of the circulation system. Summary of the Invention

[0005] This invention provides a system and process for the recycling of cryogenic liquid nitrogen in a cryogenic reactor, which solves the technical problems of sudden changes in exhaust temperature and solvent vapor concentration during batch switching of intermittent cryogenic reactors and the inability of existing static cold storage schemes to achieve continuous transfer of cold energy due to discrete valve switching.

[0006] This invention provides a cryogenic liquid nitrogen recycling system in a cryogenic reactor, including a frame base and a cryogenic reactor disposed on one side of the frame base. The frame base is provided with a tubular condenser, a double-layer adsorption tower mechanism, a cryogenic liquefaction cold box and a compression regeneration mechanism, and also includes a rotary cold storage distribution mechanism. The air inlet of the rotary cold storage distribution mechanism is connected to the exhaust pipe of the cryogenic reactor through the main air inlet pipe.

[0007] The rotary cold storage distribution mechanism includes a rotor housing, a cold storage rotor, a main shaft, a servo drive motor, a planetary gear reducer, and a rotary distribution valve. The cold storage rotor is coaxially fixed to the main shaft and located inside the rotor housing. The rotor's interior has multiple radially extending sector-shaped partitions, with adjacent partitions forming independent cold storage chambers. Each cold storage chamber is filled with several aluminum cold storage balls. The output end of the servo drive motor is connected to the input end of the planetary gear reducer, and the output end of the planetary gear reducer is connected to one end of the main shaft, driving the cold storage rotor to rotate continuously within the rotor housing.

[0008] The rotary distribution valve includes a valve body and a cylindrical valve core. The outer wall of the valve core is in clearance fit with the inner wall of the valve body. An arc-shaped flow guide channel is provided on one side of the cylindrical valve core. One end of the cylindrical valve core is connected to a valve drive motor, and the valve drive motor is electrically connected to the control cabinet.

[0009] Three sealing arc plates are fixed equidistantly along the circumference of the inner wall of the rotor housing. These sealing arc plates divide the annular space between the rotor housing and the cold storage rotor into a cold charge zone, a cold release zone, and a solvent condensation zone. End caps are fixed at both ends of the rotor housing. End face partitions are provided on the inner side of the end caps corresponding to the sealing arc plates. The ends of the end face partitions abut against the sealing arc plates, radially dividing the end face space between the end caps and the end plates of the cold storage rotor into independent gas chambers corresponding to the three functional zones.

[0010] In a preferred embodiment, the valve housing has a main air inlet at the top and symmetrically arranged charging and releasing air inlets on both sides. The main air inlet is connected to the exhaust port of the cryogenic reactor via a main air inlet pipe, and a temperature sensor is installed on the main air inlet pipe, which is electrically connected to the control cabinet. The charging air inlet is connected to the cold energy charging area via a pipe passing through an end cap, and the releasing air inlet is connected to the cold energy releasing area via a pipe passing through an end cap.

[0011] In a preferred embodiment, the bottom of the solvent condensation zone is provided with a solvent condensation collection tank and a solvent outlet. Bearing seats are respectively fitted into both ends of the main shaft and are rotatably coupled. The bearing seats are fixedly installed inside the end cover, and a sealing ring is provided between the main shaft and the end cover.

[0012] In a preferred embodiment, the sealing arc plate is an arc-shaped plate extending circumferentially along the inner wall of the rotor housing. Each sealing arc plate has multiple sealing grooves extending axially on its inner arc surface. A spring-compensated sealing strip is installed in the sealing groove. The spring-compensated sealing strip abuts against the outer wall of the cold storage rotor. The spring-compensated sealing strip is made of polytetrafluoroethylene filled with graphite material.

[0013] In a preferred embodiment, the fan-shaped partition is provided with a plurality of vent holes, and adjacent cold storage chambers are connected through the vent holes. Each cold storage chamber is provided with a drain trough at its bottom end, and a plurality of vent holes and a leakage hole are evenly distributed on both end plates, the leakage hole being connected to the drain trough.

[0014] In a preferred embodiment, the tubular condenser is provided with a condenser nitrogen inlet and a condenser nitrogen outlet. The condenser nitrogen inlet is connected to the cold energy charging zone and the cold energy release zone through a three-way valve and a pipeline. The condenser nitrogen outlet is connected to the bottom air inlet of the double-layer adsorption tower mechanism.

[0015] In a preferred embodiment, the double-layer adsorption tower mechanism includes two adsorption towers arranged in parallel. Each adsorption tower is filled with a coconut shell activated carbon layer and a 13X molecular sieve layer from bottom to top. Both adsorption towers are equipped with tower switching valve groups on their inlet and outlet pipelines.

[0016] In a preferred embodiment, the cryogenic liquefaction cold box has a high-pressure air inlet on one side and a liquid nitrogen outlet and a reflux gas outlet at the bottom. The compression regenerative mechanism includes a gas-liquid separator, a compressor, an aftercooler, and a plate-fin regenerative heat exchanger connected in sequence. The inlet of the gas-liquid separator is a low-pressure air inlet connected to the top outlet of the double-layer adsorption tower mechanism. The outlet of the plate-fin regenerative heat exchanger is connected to the high-pressure air inlet. The reflux gas outlet of the cryogenic liquefaction cold box is connected to the low-pressure side inlet of the plate-fin regenerative heat exchanger. The liquid nitrogen outlet is connected to the internal storage tank of the cryogenic reactor.

[0017] A process for recycling cryogenic liquid nitrogen in a cryogenic reactor, applied to the above system, includes the following steps: Step 1: System startup and continuous operation. The servo drive motor drives the main shaft and cold storage wheel to rotate continuously inside the wheel housing after being reduced in speed by the planetary gear reducer. This causes each cold storage chamber to pass through the cold charge zone, solvent condensation zone and cold release zone in sequence and cycle repeatedly. Step 2, Cold Charge Stage: When the temperature sensor on the main air inlet pipe detects that the low-temperature reactor is discharging low-temperature nitrogen, the control cabinet control valve drive motor drives the cylindrical valve core to rotate to the charging position. The main air inlet is connected to the charging air interface through the arc-shaped guide channel. The low-temperature nitrogen enters the cold charge zone and passes axially through the aluminum cold storage ball bed in the cold storage chamber that is passing through the cold charge zone. The low-temperature nitrogen transfers the cold energy to the aluminum cold storage ball to complete the cold storage. Step 3, Solvent pre-condensation stage: After the cold storage chamber is completed, it enters the solvent condensation zone as the cold storage wheel rotates. The surface temperature of the aluminum cold storage ball is lower than the dew point of the solvent vapor. Nitrogen carrying solvent vapor comes into contact with the low-temperature aluminum cold storage ball, and the solvent vapor condenses into a liquid film on the surface of the aluminum cold storage ball. The condensate flows along the surface of the aluminum cold storage ball to the drain trough at the bottom of the cold storage chamber, and is discharged into the end face space corresponding to the solvent condensation zone through the drain hole on the end plate. Finally, it flows into the solvent condensation collection tank and is discharged through the solvent outlet. Step 4, Cold Release and Pre-cooling Stage: When the temperature sensor detects that the low-temperature reactor is emitting high-temperature solvent-containing nitrogen, the control cabinet control valve drive motor drives the cylindrical valve core to rotate to the release position. The main air inlet is connected to the release gas path interface through the arc-shaped guide channel. The high-temperature solvent-containing nitrogen enters the cold release zone and passes through the cold storage chamber that is passing through the cold release zone along the axial direction. The aluminum cold storage ball releases the stored cold energy to continuously cool the high-temperature exhaust gas. At the same time, the residual solvent vapor further condenses on the surface of the low-temperature aluminum cold storage ball to obtain pre-cooled and pre-purified nitrogen. Step 5, Primary Condensation and Purification Stage: The nitrogen gas discharged from the cold charge zone and the cold charge release zone is combined outside the valve through a three-way valve and then introduced into the shell and tube condenser. Ethylene glycol aqueous solution is used as the refrigerant to further cool and condense the solvent vapor to obtain primary purified nitrogen gas. Step 6, Deep Adsorption and Purification Stage: The primary purified nitrogen gas is introduced into the double-layer adsorption tower structure. The nitrogen gas passes through the coconut shell activated carbon layer and the 13X molecular sieve layer from bottom to top for deep adsorption, resulting in deeply purified nitrogen gas. Step 7, Compression and Cryogenic Liquefaction Stage: Deeply purified nitrogen is reheated and compressed by a compression and reheating mechanism and then sent to a cryogenic liquefaction cold box. After turbine expansion refrigeration and throttling depressurization, it is liquefied into liquid nitrogen. The liquid nitrogen is then returned to the cryogenic reactor for recycling through the liquid nitrogen outlet. Step 8: Adsorption tower switching and regeneration stage. The double-layer adsorption tower mechanism is configured with two units operating in parallel. After the online adsorption tower has been running for 8 to 14 hours, it is switched to the standby tower. The saturated adsorption tower is then subjected to room temperature purging, high temperature regeneration desorption, and cold blowing operations in sequence. Throughout the entire process of reactor batch switching, the cold storage rotor continues to rotate continuously. Different cold storage chambers in the cold charge zone and the cold release zone simultaneously store and release cold, thereby achieving continuous transfer of cold energy and real-time smoothing of exhaust temperature.

[0018] The beneficial effects of this invention are as follows: 1. This invention uses a servo drive motor to drive the cold storage wheel to rotate continuously via a planetary gear reducer. In conjunction with an independent valve drive motor, the rotary distribution valve is switched between the charging and releasing positions according to the exhaust temperature signal. This allows each cold storage chamber of the wheel to switch continuously between the cold energy charging zone and the cold energy releasing zone. The cold energy charging and cold energy releasing are carried out simultaneously and continuously, eliminating the temperature overshoot and switching lag caused by the discrete valve switching of the existing static cold storage tank scheme. It can smooth the step fluctuation of exhaust temperature during batch switching of intermittent reactors in real time. 2. The present invention uses three sealing arc plates on the inner wall of the rotor housing and the end face partition plate on the inner side of the end cover to form a double separation structure of the outer periphery and the end face: the sealing arc plates divide the three functional areas circumferentially on the outer cylindrical surface of the cold storage rotor, and the end face partition plate divides the end face space between the end cover and the end plate radially on both ends of the rotor. The two partitions meet at the edge of the rotor to form a closed boundary, preventing the gas in different temperature ranges from mixing in the annular space and the end face space, and ensuring the zoning efficiency of cold charge and release. Attached Figure Description

[0019] Figure 1 This is an overall structural diagram of the present invention.

[0020] Figure 2 This is a structural diagram of the shell-and-tube condenser of the present invention.

[0021] Figure 3 This is a structural diagram of the double-layer adsorption tower mechanism of the present invention.

[0022] Figure 4 This is a structural diagram of the internal structure of the adsorption tower of the present invention.

[0023] Figure 5 This is a structural diagram of the cryogenic liquefaction cold box of the present invention.

[0024] Figure 6 This is a structural diagram of the compression and regeneration mechanism of the present invention.

[0025] Figure 7 This is a structural diagram of the rotary cold storage distribution mechanism of the present invention.

[0026] Figure 8 This is a structural diagram of the external structure of the rotor housing of the present invention.

[0027] Figure 9 This is a structural diagram of the internal structure of the rotor housing of the present invention.

[0028] Figure 10 This is a structural diagram of the sealing arc plate of the present invention.

[0029] Figure 11 This is a structural diagram of the cold storage rotor of the present invention.

[0030] Figure 12This is a structural diagram of the rotary distribution valve of the present invention.

[0031] In the diagram: 1. Frame base; 2. Cryogenic reactor; 3. Shell-and-tube condenser; 31. Nitrogen inlet of condenser; 32. Nitrogen outlet of condenser; 4. Double-layer adsorption tower mechanism; 41. Adsorption tower body; 42. Coconut shell activated carbon layer; 43. 13X molecular sieve layer; 411. Tower switching valve group; 5. Cryogenic liquefaction cold box; 51. High-pressure air inlet; 52. Liquid nitrogen outlet; 53. Reflux gas outlet; 6. Compression regeneration mechanism; 61. Compressor; 62. Aftercooler; 63. Gas-liquid separator; 64. Plate-fin regeneration heat exchanger; 65. Low-pressure air inlet; 7. Rotary cold storage distribution mechanism; 71. Rotary wheel housing; 711. Sealing arc plate; 7111. Sealing groove; 7112. Spring-compensated sealing strip; 712. Cold energy charging area; 713. Cold energy release... 714. Solvent condensation zone; 7141. Solvent condensation collection tank; 7142. Solvent outlet; 715. End cap; 716. End face partition; 72. Cold storage wheel; 721. Fan-shaped partition; 722. Cold storage chamber; 7221. Drainage trough bar; 7222. Leakage hole; 723. Aluminum cold storage ball; 73. Main shaft; 731. Bearing housing; 732. Sealing ring; 74. Servo drive motor; 75. Planetary gear reducer; 76. Rotary distribution valve; 761. Valve body; 7611. Main air inlet; 7612. Inlet air interface; 7613. Outlet air interface; 762. Cylindrical valve core; 763. Arc-shaped guide channel; 77. Valve drive motor; 8. Main air inlet pipeline; 81. Temperature sensor; 9. Control cabinet. Detailed Implementation

[0032] The present application will now be described in further detail with reference to the accompanying drawings. It should be noted that the following specific embodiments are only used to further illustrate the present application and should not be construed as limiting the scope of protection of the present application. Those skilled in the art can make some non-essential improvements and adjustments to the present application based on the above application content.

[0033] Example 1 like Figure 1As shown, a cryogenic liquid nitrogen recycling system and process in a cryogenic reactor includes a frame base 1 and a cryogenic reactor 2 located on one side of the frame base 1. The frame base 1 adopts a welded steel frame structure, on which a rotary cold storage distribution mechanism 7, a tubular condenser 3, a double-layer adsorption tower mechanism 4, a cryogenic liquefaction cold box 5, and a compression regeneration mechanism 6 are fixedly installed by bolts. The inlet end of the rotary cold storage distribution mechanism 7 is connected to the exhaust pipe of the cryogenic reactor 2 through a main inlet pipe 8, and the outlet end is connected to the inlet end of the tubular condenser 3. The outlet end of the tubular condenser 3 is connected to the inlet end of the double-layer adsorption tower mechanism 4, the outlet end of the double-layer adsorption tower mechanism 4 is connected to the inlet end of the compression regeneration mechanism 6, and the outlet end of the compression regeneration mechanism 6 is connected to the inlet end of the cryogenic liquefaction cold box 5. The liquid nitrogen outlet 52 of the cryogenic liquefaction cold box 5 is connected to an internal storage tank of the cryogenic reactor 2 through a pipeline for recycling liquid nitrogen.

[0034] like Figure 7 , 8 and Figure 11 As shown, the rotary cold storage distribution mechanism 7 includes a rotor housing 71, a cold storage rotor 72, a main shaft 73, a servo drive motor 74, a planetary gear reducer 75, a rotary distribution valve 76, and a valve drive motor 77.

[0035] The impeller housing 71 is a horizontal cylindrical stainless steel pressure vessel with an operating pressure of 0 to 2.0 barG. End caps 715 are fixed to both ends of the impeller housing 71. The end caps 715 are fixed to the flanges at both ends of the impeller housing 71 by flange connection. Metal spiral wound gaskets are provided on the mating surfaces to ensure vacuum sealing.

[0036] like Figure 11 As shown, the cold storage rotor 72 is coaxially fixed on the main shaft 73 and housed inside the rotor housing 71. The cold storage rotor 72 includes two circular end plates and multiple sector-shaped baffles 721 fixed between the two end plates. The sector-shaped baffles 721 are made of aluminum alloy sheet, and there are eight of them, evenly distributed circumferentially, dividing the interior of the cold storage rotor 72 into eight independent sector-shaped cold storage chambers 722. Each sector-shaped baffle 721 has multiple vent holes with a diameter of 2 to 4 mm, allowing limited gas communication between adjacent cold storage chambers 722, thus achieving pressure balance. Each cold storage chamber 722 has vent holes with a diameter of 3 to 5 mm evenly distributed on both end plates, allowing gas to pass axially through the aluminum cold storage ball 723 bed inside the cold storage chamber 722.

[0037] Each cold storage chamber 722 is filled with several aluminum cold storage balls 723. The aluminum cold storage balls 723 are made of industrial pure aluminum with a purity of not less than 99.5%, with a particle size of 4 to 6 mm, and a filling amount of 450 to 600 kg per cubic meter of cold storage chamber volume. The aluminum cold storage balls 723 have a high thermal conductivity and specific heat capacity, enabling them to complete heat exchange with the airflow in a short time.

[0038] Each cold storage chamber 722 has a drain trough 7221 at its bottom end. The drain trough 7221 is a strip-shaped groove extending axially and is formed on the inner surface of the outer peripheral wall of the cold storage chamber 722. It is used to collect the solvent liquid condensed on the surface of the aluminum cold storage ball 723 and flowing radially outward under the action of centrifugal force and gravity. Each side end plate of each cold storage chamber 722 has a drain hole 7222, which is located at the outermost radial position of the end plate and communicates with the end of the drain trough 7221. After the condensate is collected by the drain trough 7221, it is discharged into the end face space between the end cover 715 and the end plate of the cold storage wheel 72 through the drain hole 7222.

[0039] The main shaft 73 is made of 40Cr alloy steel and has undergone quenching and tempering. Both ends are supported at the inner sides of the end caps 715 of the rotor housing 71 via bearing seats 731. The bearing seats 731 contain double-row angular contact ball bearings, capable of simultaneously withstanding radial and axial forces to ensure the rotational stability of the main shaft 73. A sealing ring 732 is provided between the main shaft 73 and the end caps 715 to prevent nitrogen leakage. One end of the main shaft 73 extends out of the end cap 715 and connects to the output end of the planetary gear reducer 75.

[0040] like Figure 8 As shown, the servo drive motor 74 is an AC servo motor, and its output is connected to the input of the planetary gear reducer 75. The planetary gear reducer 75 converts the high-speed, low-torque output of the servo drive motor 74 into the low-speed, high-torque output of the spindle 73, driving the cold storage wheel 72 to rotate continuously and smoothly within the wheel housing 71.

[0041] like Figure 12 As shown, the rotary distribution valve 76 includes a valve housing 761 and a cylindrical valve core 762. The valve housing 761 is fixed to the outside of the end cap of the rotary housing 71 and is made of stainless steel. The cylindrical valve core 762 is located inside the valve housing 761, and the outer wall of the valve core 762 is in clearance fit with the inner wall of the valve housing 761. The clearance is controlled between 0.02 and 0.05 mm, which ensures that the valve core can rotate flexibly while controlling the gas leakage within the allowable range. One side of the cylindrical valve core 762 is provided with an arc-shaped flow guide channel 763. The arc-shaped flow guide channel 763 is an arc-shaped groove that is concave along the circumference of the valve core. Its arc length is 5° to 10° larger than the interval angle between the gas inlet port 7612 and the gas outlet port 7613, forming an overlap angle design. When the valve core 762 switches between the charging position and the releasing position, the main air inlet 7611 is briefly connected to the charging air path interface 7612 and the releasing air path interface 7613 simultaneously within the overlap angle interval, realizing the connection first and then disconnection, ensuring that the reactor exhaust pipeline has no interruption or pressure buildup throughout the switching process.

[0042] One end of the cylindrical valve core 762 extends out of the valve housing 761 and is connected to the valve drive motor 77. The valve drive motor 77 is a small AC servo motor, and its output shaft is directly connected to the extended shaft of the valve core 762 via a flexible coupling. The housing of the valve drive motor 77 is fixed to the outside of the end cover of the rotor housing 71 by a bracket, and is completely independent of the main shaft 73 of the cold storage rotor 72, with no mechanical transmission connection between them. The valve drive motor 77 is electrically connected to the control cabinet 9, which controls the rotation angle and position switching of the valve core 762 based on the detection signal from the temperature sensor 81.

[0043] The valve housing 761 has a main air inlet 7611 on its top, and symmetrically arranged charging air inlets 7612 and releasing air inlets 7613 on both sides. The main air inlet 7611 is connected to the exhaust port of the cryogenic reactor 2 through the main air inlet pipe 8. A temperature sensor 81 is installed on the main air inlet pipe 8. The temperature sensor 81 is a platinum resistance temperature sensor and is electrically connected to the control cabinet 9 to detect the reactor exhaust temperature in real time and transmit the signal to the control cabinet 9. The charging air inlet 7612 is connected to the cold energy charging zone 712 through a pipe through the end cap 715, and the releasing air inlet 7613 is connected to the cold energy releasing zone 713 through a pipe through the end cap 715.

[0044] Control cabinet 9 receives the detection signal from temperature sensor 81 and determines the current operating stage of the reactor based on the exhaust temperature: when the exhaust temperature is below -90℃, it is determined to be either the constant temperature reaction stage or the cooling and liquid filling stage. Control cabinet 9 controls the valve drive motor 77 to drive the valve core 762 to rotate to the filling position, so that the main air inlet 7611 is connected to the filling gas interface 7612 through the arc-shaped guide channel 763, and low-temperature nitrogen enters the cold energy filling zone 712 for cold storage; when the exhaust temperature is above -80℃, it is determined to be the heating and discharging stage. Control cabinet 9 controls the valve drive motor 77 to drive the valve core 762 to rotate to the release position, so that the main air inlet 7611 is connected to the release gas interface 7613 through the arc-shaped guide channel 763, and high-temperature nitrogen enters the cold energy release zone 713 for cooling. A 10℃ hysteresis band is set in the temperature determination range to prevent frequent switching of the valve core when the temperature fluctuates.

[0045] like Figure 9 As shown, three sealing arc plates 711 are fixed equidistantly along the circumference of the inner wall of the rotor housing 71. The sealing arc plates 711 are arc-shaped stainless steel plates extending circumferentially along the inner wall of the rotor housing 71 and are fixed to the inner wall of the rotor housing 71 by bolts. The three sealing arc plates 711 are evenly distributed circumferentially, with a central angle of 120° between adjacent sealing arc plates 711, dividing the annular space between the rotor housing 71 and the cold storage rotor 72 into three functional zones circumferentially: a cold energy charging zone 712, a cold energy release zone 713, and a solvent condensation zone 714, each occupying 120° circumferentially.

[0046] Each sealing arc plate 711 has three axially extending sealing grooves 7111 on its inner arc surface, and a spring-compensating sealing strip 7112 is installed in each sealing groove 7111. The bottom of the spring-compensating sealing strip 7112 is supported by a helical spring, and its inner end slides in contact with the outer peripheral surface of the cold storage rotor 72. The spring force keeps the sealing strip in close contact with the outer peripheral surface of the rotor, compensating for gap changes caused by wear and thermal expansion and contraction of the sealing strip. The spring-compensating sealing strip 7112 is made of polytetrafluoroethylene-filled graphite material, which has a low coefficient of friction and good low-temperature resistance, and meets the dynamic sealing requirements of continuous rotation of the cold storage rotor 72, preventing gas mixing between the three functional areas on the outer peripheral surface of the rotor.

[0047] An end face partition 716 is provided on the inner side of the end cover 715 corresponding to the position of the sealing arc plate 711. The end face partition 716 is a long strip of stainless steel plate extending radially, fixed to the inner side of the end cover 715 by bolts, and its length extends from near the center of the cold storage rotor 72 to the outer circumference of the rotor. The outer end of the end face partition 716 abuts against the end of the sealing arc plate 711, and the inner end extends to the sealing bushing around the main shaft 73. The three end face partitions 716 are evenly distributed circumferentially on the inner side of the end cover 715 on each side, with a central angle of 120° between adjacent two partitions, and are aligned with the circumferential positions of the three sealing arc plates 711, thereby dividing the annular end face space between the end cover 715 and the end plate of the cold storage rotor 72 radially into three independent fan-shaped gas chambers on each end face of the rotor, corresponding to the cold charge zone 712, the cold release zone 713, and the solvent condensation zone 714, respectively.

[0048] The spring-compensated sealing strip 7112 on the outer circumferential surface and the end face partitions 716 on both ends together constitute a complete separation and sealing system: the outer circumferential sealing strip is responsible for the circumferential sealing of the cylindrical surface of the wheel, and the end face partitions are responsible for the radial sealing of the two ends of the wheel. The two partitions meet at the four edges of the wheel, so that each functional area forms a closed space that is connected to the outside world only through the vent hole and the leakage hole of the cold storage chamber end plate, preventing end face leakage and peripheral leakage between the cold energy charging area 712 and the cold energy release area 713.

[0049] The solvent condensation zone 714 has a solvent condensation collection tank 7141 and a solvent outlet 7142 at its bottom. The solvent condensation collection tank 7141 is an arc-shaped collection tank extending axially along the bottom of the rotor housing 71, located at the lowest point of the solvent condensation zone 714, and is used to collect the solvent condensate discharged from the drain hole 7222 on the end plate of the cold storage chamber 722 into the end face space of the solvent condensation zone 714. The solvent outlet 7142 is located at the lowest point of the solvent condensation collection tank 7141 and is connected to an external solvent recovery storage tank through a cryogenic shut-off valve.

[0050] like Figure 1As shown, the tubular condenser 3 is equipped with a nitrogen inlet 31 and a nitrogen outlet 32. The nitrogen inlet 31 is connected to the outlets of the cooling capacity charging zone 712 and the cooling capacity release zone 713 via a three-way valve and pipeline. The nitrogen discharged from the cooling capacity charging zone 712 and the cooling capacity release zone 713 merges outside the valve through the three-way valve and then enters the tubular condenser 3. The nitrogen outlet 32 ​​is connected to the bottom inlet of the double-layer adsorption tower mechanism 4. The tubular condenser 3 uses an ethylene glycol aqueous solution with a temperature of -15 to -25°C and a mass fraction of 50% to 60% as the refrigerant to further cool the nitrogen to -30 to -45°C, condensing and removing residual solvent vapors. After condensation, the solvent vapor concentration in the outlet nitrogen is reduced to 100 to 200 ppm.

[0051] The dual-layer adsorption tower mechanism 4 includes two adsorption towers 41 connected in parallel. Each adsorption tower 41 is a vertical cylindrical stainless steel pressure vessel, with a coconut shell activated carbon layer 42 and a 13X molecular sieve layer 43 filled sequentially from bottom to top inside. The coconut shell activated carbon layer 42 is used to adsorb residual organic solvent vapors, and the 13X molecular sieve layer 43 is used for deep removal of moisture. Both adsorption towers 41 are equipped with tower switching valve groups 411 on their inlet and outlet pipelines, enabling parallel operation with one tower in online adsorption and the other in standby or regeneration mode. The dual-layer adsorption tower operates at -10 to 0°C and a pressure of 0.5 to 1.5 barG, with a solvent content in the outlet nitrogen gas below 1 ppm and a moisture dew point below -70°C.

[0052] like Figure 5 , Figure 6 As shown, the cryogenic liquefaction cold box 5 uses a perlite vacuum powder insulated box body, with a high-pressure air inlet 51 on one side and a liquid nitrogen outlet 52 and a return gas outlet 53 at the bottom. The cryogenic liquefaction cold box 5 contains a primary plate-fin heat exchanger, a secondary plate-fin heat exchanger, a primary turbine expander, a secondary turbine expander, and a throttling valve. High-pressure nitrogen is divided into two paths within the cold box. The first path is cooled by the primary plate-fin heat exchanger and then sent to the primary turbine expander to provide cooling capacity. The second path is cooled sequentially by the primary and secondary plate-fin heat exchangers, with part of it being depressurized and liquefied into liquid nitrogen product by the throttling valve, and the remainder being expanded by the secondary turbine expander to provide cooling capacity. The liquid nitrogen product is sent to a storage tank through the liquid nitrogen outlet 52 and then returned to the cryogenic reactor 2 for recycling.

[0053] The compression regenerative mechanism 6 includes a gas-liquid separator 63, a compressor 61, an aftercooler 62, and a plate-fin regenerative heat exchanger 64 connected in sequence. The gas-liquid separator 63 has a low-pressure inlet 65 at its inlet, which connects to the top outlet of the double-layer adsorption tower mechanism 4, used to separate liquid droplets that may be carried in the nitrogen gas. The compressor 61 is a screw compressor that pressurizes the low-pressure nitrogen gas to 5 to 8 barG. The aftercooler 62 uses circulating cooling water as a refrigerant to cool the pressurized high-temperature nitrogen gas to room temperature. The plate-fin regenerative heat exchanger 64 recovers the cooling capacity of the reflux low-temperature nitrogen gas for pre-cooling the high-pressure nitrogen gas. Its high-pressure side outlet is connected to the high-pressure inlet 51 of the cryogenic liquefaction cold box 5, and the reflux gas outlet 53 of the cryogenic liquefaction cold box 5 is connected to the low-pressure side inlet of the plate-fin regenerative heat exchanger 64.

[0054] The working principle of the rotary cold storage distribution mechanism 7 in this embodiment is as follows: the servo drive motor 74 drives the main shaft 73 and the cold storage wheel 72 to rotate continuously after being reduced in speed by the planetary gear reducer 75. As the cold storage wheel 72 rotates, each cold storage chamber 722 sequentially passes through the cold energy charging zone 712, the solvent condensation zone 714, and the cold energy release zone 713 and cycles back and forth. At any given time, 2 to 3 cold storage chambers 722 in the cold energy charging zone 712 are absorbing the cold energy from the low-temperature exhaust gas, 2 to 3 cold storage chambers 722 in the cold energy release zone 713 are releasing cold energy to cool the high-temperature exhaust gas, and 2 to 3 cold storage chambers 722 in the solvent condensation zone 714 are undergoing solvent condensation and drainage. The cold energy charging and cold energy release occur simultaneously and continuously, eliminating the switching lag and temperature overshoot problems associated with static cold storage tank schemes.

[0055] The valve drive motor 77 independently drives the cylindrical valve core 762 of the rotary distribution valve 76 to switch between the charging and releasing positions based on the signal received from the temperature sensor 81 in the control cabinet 9. When the reactor discharges low-temperature nitrogen, the valve core 762 rotates to the charging position, and the main air inlet 7611 connects to the charging gas interface 7612 through the arc-shaped guide channel 763, allowing low-temperature nitrogen to enter the cold energy charging zone 712. When the reactor discharges high-temperature nitrogen, the valve core 762 rotates to the releasing position, and the main air inlet 7611 connects to the releasing gas interface 7613 through the arc-shaped guide channel 763, allowing high-temperature nitrogen to enter the cold energy releasing zone 713. During the switching process of the valve core 762, the 5° to 10° overlap angle of the arc-shaped guide channel 763 ensures a smooth, uninterrupted switching process. The outer peripheral spring-compensated sealing strip 7112 and the end face partitions 716 maintain a dynamic separation seal during the rotation of the rotor, ensuring that gases in each functional area do not mix.

[0056] The discharge path of the solvent condensate is as follows: the solvent liquid condensed on the surface of the aluminum cold storage ball 723 flows along the surface of the cold storage ball to the radial outer side of the cold storage chamber 722 under the combined action of centrifugal force and gravity, and collects in the drain trough 7221 at the bottom of the cold storage chamber 722. It flows axially along the drain trough 7221 to the end plate, and is discharged into the end face fan-shaped gas chamber corresponding to the solvent condensation area 714 through the leakage hole 7222 on the end plate. It flows downward along the inner wall of the end cover 715 under the action of gravity into the solvent condensation collection tank 7141, and is finally discharged through the solvent outlet 7142.

[0057] The cryogenic liquid nitrogen recycling process in the cryogenic reactor of this embodiment includes the following steps: Step 1: System Start-up and Continuous Operation. Start the servo drive motor 74, which, after being reduced in speed by the planetary gear reducer 75, drives the main shaft 73 and the cold storage wheel 72 to rotate continuously within the wheel housing 71 at a speed of 2 r / min. As the cold storage wheel 72 rotates, the eight cold storage chambers 722 sequentially pass through the cold charge zone 712, the solvent condensation zone 714, and the cold release zone 713 in a cyclical manner. At any given time, two to three cold storage chambers 722 in both the cold charge zone 712 and the cold release zone 713 are operating simultaneously.

[0058] Step 2, Cold Charge Stage. When the cryogenic reactor is in the isothermal reaction stage (exhaust temperature -130℃) or the re-cooling and liquid filling stage (exhaust temperature -150℃), the temperature sensor 81 on the main intake pipe 8 detects that the exhaust temperature is below -90℃. The control cabinet 9 determines that it is in the cryogenic exhaust stage, and the control valve drive motor 77 drives the cylindrical valve core 762 to rotate to the charging position. The main air inlet 7611 is connected to the charging gas interface 7612 through the arc-shaped guide channel 763. Cryogenic nitrogen enters the cold charge zone 712 through the charging gas interface 7612 and the pipe that passes through the end cover 715. Low-temperature nitrogen gas passes axially through two to three cold storage chambers 722 that are currently passing through the cold charge zone 712. It then enters the aluminum cold storage ball 723 bed within the cold storage chamber 722 through the end plate vents. The low-temperature nitrogen gas transfers its cooling capacity to the aluminum cold storage balls 723, causing their temperature to drop to -140°C, thus completing the cold storage process. After heat exchange, the nitrogen gas temperature rises to -90°C and flows out from the outlet of the cold charge zone 712.

[0059] Step 3: Solvent Pre-condensation Stage. After the cold storage chamber 722 has completed its cold storage, it rotates from the cold charge zone 712 into the solvent condensation zone 714 along with the cold storage rotor 72. At this time, the surface temperature of the aluminum cold storage ball 723 is approximately -140℃, far below the dew point temperature of solvent vapors such as tetrahydrofuran. Nitrogen gas carrying solvent vapor comes into contact with the low-temperature aluminum cold storage ball 723 in this section, and the solvent vapor condenses into a liquid film on the surface of the aluminum cold storage ball 723. Under the combined action of centrifugal force and gravity, the condensate flows along the surface of the aluminum cold storage ball 723 to the radial outer side of the cold storage chamber 722, and collects in the drain trough 7221 at the bottom of the cold storage chamber 722. It flows axially along the drain trough 7221 to the end plate, and is discharged into the fan-shaped gas chamber on the end face corresponding to the solvent condensation zone 714 through the leakage hole 7222 on the end plate. It then flows downward along the inner wall of the end cover 715 into the solvent condensation collection tank 7141, and is discharged to the external solvent recovery storage tank through the solvent outlet 7142 and the low temperature shut-off valve.

[0060] Step 4: Cold Release and Pre-cooling Stage. When the reactor enters the heating and discharge stage, the temperature of the discharged nitrogen gas jumps to -55°C, and the concentration of tetrahydrofuran vapor surges to 4500 ppm. Temperature sensor 81 detects that the exhaust temperature is higher than -80°C, and control cabinet 9 determines it to be in the high-temperature exhaust stage. Control valve drive motor 77 drives the cylindrical valve core 762 to rotate to the release position. The main inlet 7611 is connected to the release gas interface 7613 through the arc-shaped guide channel 763. High-temperature solvent-containing nitrogen gas enters the cold release zone 713 through the release gas interface 7613 and the pipe penetrating the end cover 715, passing axially through 2 to 3 cold storage chambers 722 that are passing through the cold release zone 713. The aluminum cold storage ball 723 (previously cooled to -140°C in the cold charge zone 712) releases the stored cold energy to continuously cool the high-temperature exhaust gas, reducing the exhaust temperature from -55°C to -80°C. Meanwhile, the residual solvent vapors further condense on the surface of the low-temperature aluminum cold storage ball 723, and the solvent vapor concentration in the nitrogen gas exiting the tank decreases from 4500ppm to 2550ppm, resulting in pre-cooled and pre-purified nitrogen gas, which flows out from the outlet of the cold energy release zone 713.

[0061] At the instant the reactor switches from the constant temperature reaction stage to the heating and discharge stage, the cold storage rotor 72 continues to rotate continuously, and the cold energy release zone 713 always has the cold storage chamber 722 that has stored cold energy releasing cold energy. There is no lag problem in the static cold storage tank scheme where the cold energy is not ready before switching to the cold release mode, and the temperature fluctuation is smoothed in real time.

[0062] Step 5: Primary Condensation and Purification Stage. Nitrogen gas discharged from the cold charge zone 712 and the cold release zone 713 merges outside the valve via a three-way valve and is then introduced into the condenser nitrogen inlet 31 of the shell-and-tube condenser 3 through a connecting pipeline. An independently configured chiller unit provides a 55% (-20℃) ethylene glycol aqueous solution refrigerant, which exchanges heat counter-currently with the tube-side nitrogen in the shell side of the shell-and-tube condenser 3. The pre-cooled and pre-purified nitrogen gas is further cooled to -35℃. The remaining solvent vapor in the nitrogen condenses into liquid on the outer wall of the heat exchange tube bundle, flows along the tube wall to the bottom liquid seal, and is discharged to the solvent recovery storage tank through the condensate outlet. After condensation, the solvent vapor concentration in the outlet nitrogen gas drops to 150 ppm, resulting in primary purified nitrogen gas, which flows out from the condenser nitrogen outlet 32.

[0063] Step Six: Deep Adsorption and Purification Stage. Primary purified nitrogen is introduced into the bottom inlet of the online adsorption tower 41 of the double-layer adsorption tower mechanism 4. After being evenly distributed by the gas distributor, it flows upwards, passing sequentially through the coconut shell activated carbon layer 42 and the 13X molecular sieve layer 43. The coconut shell activated carbon layer 42 adsorbs residual organic solvent vapors, while the 13X molecular sieve layer 43 deeply removes moisture. The double-layer adsorption tower operates at -5℃ and 1.0 barG. The adsorbed nitrogen flows out from the top outlet of the adsorption tower. The solvent content in the outlet nitrogen is less than 1 ppm, and the moisture dew point is less than -70℃, resulting in deeply purified nitrogen. Because the rotary cold storage distribution mechanism 7 has pre-reduced the solvent concentration from 4500 ppm to 2550 ppm, and the tubular condenser 3 further reduces it to 150 ppm, the inlet load of the double-layer adsorption tower is significantly reduced, and a single operating cycle can reach 11 hours.

[0064] Step 7: Compression and Cryogenic Liquefaction Stage. Deeply purified nitrogen is fed into the low-pressure inlet 65 of the compression regenerative mechanism 6. It first enters the gas-liquid separator 63 to separate any potential liquid droplets, and then enters the compressor 61 to be pressurized to 7 barG. The pressurized high-temperature nitrogen enters the aftercooler 62, where it is cooled to 35°C using circulating cooling water as the refrigerant, resulting in high-pressure ambient-temperature nitrogen. This high-pressure ambient-temperature nitrogen enters the high-pressure side of the plate-fin regenerative heat exchanger 64, where it undergoes counter-current heat exchange with the low-pressure nitrogen returning from the cryogenic liquefaction chamber 5. After pre-cooling, the high-pressure nitrogen exits from the high-pressure side outlet and is then fed into the high-pressure inlet 51 of the cryogenic liquefaction chamber 5 via a vacuum-insulated pipe.

[0065] High-pressure, ambient-temperature nitrogen gas enters the cryogenic liquefaction chamber 5 and splits into two streams. The first stream, accounting for 35% of the total gas volume, is cooled by a primary plate-fin heat exchanger and then expanded to 1.0 barG by a primary turbine expander, providing cooling capacity for the high-temperature section. The expanded cryogenic nitrogen gas returns to the low-pressure side of the primary plate-fin heat exchanger. The second stream, accounting for 65% of the total gas volume, is cooled sequentially by primary and secondary plate-fin heat exchangers. Of this, 45% is depressurized to 1.5 barG via a throttling valve, and liquefied into liquid nitrogen at -196℃. This liquid nitrogen is then sent to a storage tank via liquid nitrogen outlet 52 and returned to cryogenic reactor 2 for recycling. The remaining 20% ​​is sent to a secondary turbine expander to 1.0 barG, providing cooling capacity for the cryogenic section, and then returned to the low-pressure side of the secondary plate-fin heat exchanger. The returned cryogenic nitrogen gas flows out from return gas outlet 53 and returns to the low-pressure side of the plate-fin regenerative heat exchanger 64 for reheating and recycling.

[0066] Since the rotary cold storage distribution mechanism 7 has smoothed the exhaust temperature fluctuation to the range of -80 to -90℃, the nitrogen entering the cryogenic liquefaction cold box 5 tends to be constant after reheating and compression. The temperature field of each heat exchanger in the cryogenic cold box remains stable, and the liquid nitrogen production is not interrupted due to the batch switching of the reactor.

[0067] Step 8: Adsorption Tower Switching and Regeneration Stage. The double-layer adsorption tower mechanism 4 is configured with two units operating in parallel. After the online adsorption tower has been running for 11 hours, if the online photoionization detector or dew point meter detects that the outlet solvent content is close to 1 ppm or the moisture dew point is close to -70℃, the control cabinet 9 activates the tower switching valve group 411, switching the airflow to the standby adsorption tower for continued operation. The saturated adsorption tower is then subjected to the following sequential steps: purging with 20℃ dry nitrogen at room temperature for 0.75 hours to replace residual gas; starting the electric heater to heat the regeneration nitrogen to 250℃ for high-temperature regeneration and desorption for 3 hours; the desorption tail gas is cooled to -15℃ via a cold trap, the solvent vapor condenses into liquid and is discharged into the solvent collection tank, and the non-condensable tail gas is treated by the tail gas treatment device before being discharged; the electric heater is stopped, and 20℃ dry nitrogen is introduced for cold purging for 1.5 hours until the tower temperature drops to room temperature. After regeneration is completed, the tower is switched to standby mode.

[0068] Throughout the entire reactor batch switching process, the cold storage rotor 72 maintains continuous rotation. The cold energy charging zone 712 and the cold energy release zone 713 simultaneously have different cold storage chambers 722 for cold energy storage and release, respectively, achieving continuous cold energy transfer and real-time smoothing of the exhaust temperature. The rotational speed of the servo drive motor 74 is dynamically adjusted according to the reactor operation stage: the speed is 1 r / min during the isothermal reaction stage, the speed is increased to 3 to 5 r / min during the heating and discharging stage to increase the cold energy release rate, and the speed is 2 r / min during the cooling and liquid filling stage to accelerate the cold energy storage rate.

[0069] The embodiments described above are merely examples of several implementations of the present invention, and while the descriptions are relatively specific and detailed, they should not be construed as limiting the scope of the present invention. It should be noted that those skilled in the art can make various modifications and improvements without departing from the concept of the present invention, and these modifications and improvements all fall within the scope of protection of the present invention.

Claims

1. A cryogenic liquid nitrogen recycling system in a cryogenic reactor, comprising a frame base (1) and a cryogenic reactor (2) disposed on one side of the frame base (1), wherein the frame base (1) is provided with a tubular condenser (3), a double-layer adsorption tower mechanism (4), a cryogenic liquefaction cold box (5), and a compression regeneration mechanism (6), characterized in that, It also includes a rotary cold storage distribution mechanism (7), the air inlet of which is connected to the exhaust pipe of the low temperature reactor (2) through the main air inlet pipe (8); The rotary cold storage distribution mechanism (7) includes a wheel housing (71), a cold storage wheel (72), a main shaft (73), a servo drive motor (74), a planetary gear reducer (75), and a rotary distribution valve (76). The cold storage wheel (72) is coaxially fixed on the main shaft (73) and located inside the wheel housing (71). The interior of the cold storage wheel (72) is provided with multiple radially extending fan-shaped partitions (721). Adjacent fan-shaped partitions (721) form independent cold storage chambers (722). Each cold storage chamber (722) is filled with several aluminum cold storage balls (723). The output end of the servo drive motor (74) is connected to the input end of the planetary gear reducer (75), and the output end of the planetary gear reducer (75) is connected to one end of the main shaft (73). The rotary distribution valve (76) includes a valve body (761) and a cylindrical valve core (762). The outer wall of the valve core (762) is in clearance fit with the inner wall of the valve body (761). An arc-shaped flow guide channel (763) is provided on one side of the cylindrical valve core (762). One end of the cylindrical valve core (762) is connected to a valve drive motor (77). The valve drive motor (77) is electrically connected to the control cabinet (9).

2. The cryogenic liquid nitrogen recycling system in a cryogenic reactor according to claim 1, characterized in that, The inner wall of the rotor housing (71) is fixed with three sealing arc plates (711) at equal intervals along the circumference. The sealing arc plates (711) divide the annular space between the rotor housing (71) and the cold storage rotor (72) into a cold charge zone (712), a cold release zone (713), and a solvent condensation zone (714). The rotor housing (71) is fixed with end caps (715) at both ends. The end caps (715) are provided with end face partitions (716) on the inner side of the end caps (715) corresponding to the sealing arc plates (711). The end of the end face partitions (716) abuts against the sealing arc plates (711).

3. The cryogenic liquid nitrogen recycling system in a cryogenic reactor according to claim 2, characterized in that, The valve housing (761) is provided with a main air inlet (7611) at the top, and a charging air inlet (7612) and a releasing air inlet (7613) are symmetrically provided on both sides. The main air inlet (7611) is connected to the exhaust port of the low-temperature reactor (2) through the main air inlet pipe (8). A temperature sensor (81) is provided on the main air inlet pipe (8). The temperature sensor (81) is electrically connected to the control cabinet (9). The charging air inlet (7612) is connected to the cold energy charging area (712) through the pipe through end cap (715). The releasing air inlet (7613) is connected to the cold energy releasing area (713) through the pipe through end cap (715).

4. The cryogenic liquid nitrogen recycling system in a cryogenic reactor according to claim 3, characterized in that, The solvent condensation zone (714) is provided with a solvent condensation collection tank (7141) and a solvent outlet (7142) at the bottom. The main shaft (73) is fitted with bearing seats (731) at both ends and rotates in cooperation. The bearing seats (731) are fixedly installed inside the end cover (715). A sealing ring (732) is provided between the main shaft (73) and the end cover (715).

5. A cryogenic liquid nitrogen recycling system in a cryogenic reactor according to claim 4, characterized in that, The sealing arc plate (711) is an arc-shaped plate extending circumferentially along the inner wall of the wheel housing (71). Each sealing arc plate (711) has multiple sealing grooves (7111) extending axially on its inner arc surface. A spring compensation sealing strip (7112) is installed in the sealing groove (7111). The spring compensation sealing strip (7112) abuts against the outer wall of the cold storage wheel (72). The spring compensation sealing strip (7112) is made of polytetrafluoroethylene filled with graphite material.

6. A cryogenic liquid nitrogen recycling system in a cryogenic reactor according to claim 5, characterized in that, The fan-shaped partition (721) is provided with several vent holes, and the adjacent cold storage chambers (722) are connected through the vent holes. Each cold storage chamber (722) is provided with a drain trough (7221) at the bottom end, and several vent holes and a leakage hole (7222) are evenly distributed on both side end plates. The leakage hole (7222) is connected to the drain trough (7221).

7. A cryogenic liquid nitrogen recycling system in a cryogenic reactor according to claim 6, characterized in that, The tubular condenser (3) is provided with a condenser nitrogen inlet (31) and a condenser nitrogen outlet (32). The condenser nitrogen inlet (31) is connected to the cold charge charging zone (712) and the cold release zone (713) through a three-way valve and pipeline. The condenser nitrogen outlet (32) is connected to the bottom air inlet of the double-layer adsorption tower mechanism (4).

8. A cryogenic liquid nitrogen recycling system in a cryogenic reactor according to claim 7, characterized in that, The double-layer adsorption tower mechanism (4) includes two adsorption towers (41) arranged in parallel. Each adsorption tower (41) is filled with a coconut shell activated carbon layer (42) and a 13X molecular sieve layer (43) from bottom to top. Both the inlet and outlet pipes of the two adsorption towers (41) are equipped with tower switching valve groups (411).

9. A cryogenic liquid nitrogen recycling system in a cryogenic reactor according to claim 8, characterized in that, The cryogenic liquefaction cold box (5) is provided with a high-pressure air inlet (51) on one side, and a liquid nitrogen outlet (52) and a reflux gas outlet (53) at the bottom. The compression regeneration mechanism (6) includes a gas-liquid separator (63), a compressor (61), an aftercooler (62), and a plate-fin regeneration heat exchanger (64) connected in sequence. The inlet of the gas-liquid separator (63) is a low-pressure air inlet (65) connected to the top outlet of the double-layer adsorption tower mechanism (4). The outlet of the plate-fin regeneration heat exchanger (64) is connected to the high-pressure air inlet (51). The reflux gas outlet (53) of the cryogenic liquefaction cold box (5) is connected to the low-pressure side inlet of the plate-fin regeneration heat exchanger (64). The liquid nitrogen outlet (52) is connected to the internal storage tank of the cryogenic reactor (2).

10. The process for recycling cryogenic liquid nitrogen in a cryogenic reactor according to claim 9, characterized in that, The cryogenic liquid nitrogen recycling system applied to any one of claims 1-9 in a cryogenic reactor includes the following steps: Step 1: System startup and continuous operation, the servo drive motor (74) drives the main shaft (73) and the cold storage wheel (72) to rotate continuously in the wheel housing (71) after being reduced by the planetary gear reducer (75), so that each cold storage chamber (722) passes through the cold energy charging zone (712), the solvent condensation zone (714) and the cold energy release zone (713) in sequence and cycles back and forth; Step 2, cold energy charging stage: When the temperature sensor (81) on the main air inlet pipe (8) detects that the low temperature reactor (2) is discharging low temperature nitrogen, the control cabinet (9) controls the valve drive motor (77) to drive the cylindrical valve core (762) to rotate to the charging station. The main air inlet (7611) is connected to the charging air interface (7612) through the arc-shaped guide channel (763). The low temperature nitrogen enters the cold energy charging zone (712) and passes through the aluminum cold storage ball (723) bed in the cold storage chamber (722) that is passing through the cold energy charging zone (712) along the axis. The low temperature nitrogen transfers the cold energy to the aluminum cold storage ball (723) to complete the cold storage. Step 3, Solvent pre-condensation stage: After the cold storage chamber (722) is completed, it rotates with the cold storage wheel (72) and enters the solvent condensation zone (714). The surface temperature of the aluminum cold storage ball (723) is lower than the dew point of the solvent vapor. Nitrogen carrying solvent vapor comes into contact with the low temperature aluminum cold storage ball (723). The solvent vapor condenses into a liquid film on the surface of the aluminum cold storage ball (723). The condensate flows along the surface of the aluminum cold storage ball (723) to the drain trough (7221) at the bottom of the cold storage chamber (722). It is discharged into the end face space corresponding to the solvent condensation zone (714) through the drain hole (7222) on the end plate and finally flows into the solvent condensation collection tank (7141) and is discharged through the solvent outlet (7142). Step 4, Cold Release and Pre-cooling Stage: When the temperature sensor (81) detects that the low-temperature reactor (2) is discharging high-temperature solvent-containing nitrogen, the control cabinet (9) controls the valve drive motor (77) to drive the cylindrical valve core (762) to rotate to the release position. The main air inlet (7611) is connected to the release gas interface (7613) through the arc-shaped guide channel (763). The high-temperature solvent-containing nitrogen enters the cold release zone (713) and passes through the cold storage chamber (722) which is passing through the cold release zone (713) along the axial direction. The aluminum cold storage ball (723) releases the stored cold energy to continuously cool the high-temperature exhaust gas. At the same time, the residual solvent vapor is further condensed on the surface of the low-temperature aluminum cold storage ball (723) to obtain pre-cooled and pre-purified nitrogen. Step 5, Primary condensation and purification stage: The nitrogen discharged from the cold charge zone (712) and the cold release zone (713) is combined outside the valve through a three-way valve and then introduced into the shell and tube condenser (3). Ethylene glycol aqueous solution is used as the refrigerant to further cool and condense to remove solvent vapor, and primary purified nitrogen is obtained. Step 6, Deep Adsorption and Purification Stage: The primary purified nitrogen gas is introduced into the double-layer adsorption tower mechanism (4). The nitrogen gas passes through the coconut shell activated carbon layer (42) and the 13X molecular sieve layer (43) from bottom to top for deep adsorption, and the deep purified nitrogen gas is obtained. Step 7, compression and cryogenic liquefaction stage: Deeply purified nitrogen gas is reheated and compressed by the compression and reheating mechanism (6) and then sent to the cryogenic liquefaction cold box (5). After turbine expansion refrigeration and throttling depressurization, it is liquefied into liquid nitrogen. The liquid nitrogen is sent back to the cryogenic reactor (2) through the liquid nitrogen outlet (52) for recycling. Step 8, Adsorption Tower Switching and Regeneration Stage: The double-layer adsorption tower mechanism (4) is configured with two units operating in parallel. After the online adsorption tower has been running for 8 to 14 hours, it is switched to the standby tower. The saturated adsorption tower is then subjected to ambient temperature purging, high temperature regeneration desorption, and cold blowing operations in sequence. During the entire process of reactor batch switching, the cold storage rotor (72) keeps rotating continuously. The cold energy charging zone (712) and the cold energy release zone (713) have different cold storage chambers (722) for cold storage and cold release respectively, so as to realize the continuous transfer of cold energy and the real-time smoothing of exhaust temperature.

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