A device for recycling hydrogen fluoride in tail gas of uranium dioxide hydrofluorination process

Abstract

A device for recycling hydrogen fluoride in tail gas of uranium dioxide hydrofluorination process belongs to the technical field of uranium conversion production. The present invention is to improve the utilization rate of hydrogen fluoride in tail gas of hydrofluorination process and reduce the generation rate of fluorine-containing waste in the preparation process of uranium tetrafluoride. The present invention includes a feeding hopper, a feeding screw conveyor, a moving bed and a discharging screw conveyor. The feeding screw conveyor feeds the material in the feeding hopper into the moving bed, and the discharging screw conveyor discharges the material in the moving bed. The present invention feeds uranium dioxide material into the moving bed through the feeding screw conveyor, and introduces hydrogen fluoride in the tail gas of uranium dioxide hydrofluorination process into the moving bed in a countercurrent manner, so that hydrogen fluoride is fully in contact with uranium dioxide, thereby increasing the absorption rate of uranium dioxide and hydrogen fluoride in the tail gas.

Description

Technical Field

[0001] The invention relates to a device for recycling hydrogen fluoride in tail gas of a uranium dioxide hydrofluorination process, belonging to the technical field of uranium conversion production. Background Art

[0002] In the field of uranium conversion production, in the process of preparing uranium tetrafluoride by uranium dioxide hydrofluorination, excessive hydrogen fluoride measures are taken to improve the utilization rate of metallic uranium. An important indicator for testing the quality of hydrofluorination (hydrofluorination refers to the process of generating uranium tetrafluoride by the reaction of uranium dioxide and anhydrous hydrogen fluoride) processes and equipment is to make full use of hydrogen fluoride while obtaining high-quality uranium tetrafluoride products at a high yield.

[0003] At present, there are three main types of hydrogen fluoride recovery devices:

[0004] The first device is a distillation tower, which specifically utilizes the physical properties of hydrogen fluoride itself to separate the waste acid by simple distillation. However, this route is not feasible in practice. The main reason is that water is a liquid at room temperature, while HF (hydrogen fluoride) is a gas at room temperature. The boiling point of water is 100°C, while the boiling point of HF is 19.5°C. The two will form an azeotrope during the distillation separation process. The azeotrope exists in the form of HF-H2O, so it is impossible to obtain HF with a content of 99%.

[0005] The second device is a sodium fluoride absorption tower, which can recover all the hydrogen fluoride in the waste acid. The sodium fluoride generated after pyrolysis can be recycled as a raw material. No other by-products are produced, and no secondary pollution is caused. However, the test verification found that due to the loss of some sodium fluoride and hydrogen fluoride when the supernatant was drawn off, the sodium fluoride could not be fully recycled, and the hydrogen fluoride recovery rate did not meet the design requirements.

[0006] The third device is the "LC" furnace. The international uranium conversion industry and its technological development show that in the process of preparing uranium tetrafluoride by hydrofluorination, the selection of appropriate process equipment and the reasonable arrangement of the process can achieve direct recycling of excess hydrogen fluoride. The so-called direct recycling refers to the process in which hydrogen fluoride is directly returned to the main process without recovery treatment. In this regard, the low-temperature adsorption of the French "LC" furnace production process is a good method. The HF concentration of the tail gas of the "LC" furnace equipment is 2% to 5%, which represents the current international advanced level.

[0007] At present, the tail gas treatment method of uranium conversion hydrofluorination process is to neutralize it with lime after condensation, which produces a large amount of lime slag secondary waste that is difficult to handle and dispose of.

[0008] Based on the above situation, research on the recovery and reuse technology of hydrogen fluoride in the tail gas of the hydrofluorination process is carried out to improve and perfect the existing production system. This is of great significance to ensure the stable operation of uranium conversion facilities, improve the utilization rate of hydrogen fluoride, reduce the generation rate of fluorine-containing waste in the preparation process of uranium tetrafluoride from the source, and ensure the safe operation and environmental safety of uranium conversion facilities. Summary of the invention

[0009] The present invention aims to improve the utilization rate of hydrogen fluoride in the tail gas of the hydrofluorination process and reduce the generation rate of fluorine-containing waste in the preparation process of uranium tetrafluoride. A brief summary of the present invention is given below to provide a basic understanding of certain aspects of the present invention. It should be understood that this summary is not an exhaustive summary of the present invention. It is not intended to identify the key or important parts of the present invention, nor is it intended to limit the scope of the present invention.

[0010] The technical solution of the present invention:

[0011] A device for recycling hydrogen fluoride in tail gas of uranium dioxide hydrofluorination process comprises a feed hopper, a feed screw conveyor, a moving bed and a discharge screw conveyor. The feed screw conveyor feeds materials in the feed hopper into the moving bed, and the discharge screw conveyor discharges materials in the moving bed.

[0012] Preferably: the moving bed includes a bed body, a moving center axis and a ring plate, the bed body is provided with a feed pipe and an air inlet pipe, the top of the bed body is provided with an air outlet pipe, the bottom of the bed body is provided with a discharge port, the feed screw conveyor establishes a matching installation relationship with the feed pipe, the discharge port at the bottom of the bed body establishes a matching installation relationship with the unloading screw conveyor, a moving center axis is provided in the bed body, and a ring plate is arranged on the moving center axis.

[0013] Preferably, the air outlet pipe is connected to the dust collector through a conduit.

[0014] Preferably, the output end of the unloading screw conveyor is connected to the unloading chamber.

[0015] Preferably, the moving bed is installed via a discharging telescopic hopper and a discharging screw conveyor.

[0016] Preferably, a material inlet pipe is provided at the upper part of the unloading telescopic hopper to connect with the discharge port of the moving bed, a stuffing sealing box is provided between the discharge port and the unloading telescopic hopper, and the lower part of the unloading telescopic hopper is connected with the silo of the unloading screw conveyor.

[0017] Preferably, the feed pipe and the air intake pipe are both installed on the side wall of the bed, the feed pipe is arranged at the upper part of the bed, and the air intake pipe is arranged at the lower part of the bed.

[0018] Preferably, the feed pipe is arranged and installed on the bed in an inclined manner.

[0019] Preferably, the inclination angle formed by the feed pipe and the axis of the bed is 20-60°.

[0020] Preferably, an upper cover is installed on the top of the bed, and the upper end of the moving central axis passes through the upper cover and is connected to a vibration mechanism.

[0021] Preferably: the vibration mechanism includes a motor, a cam and a transmission rod, the cam is an eccentric rotating cam, the cam is installed on the output shaft of the motor, the transmission rod is connected to the fulcrum O, one end of the transmission rod establishes an installation relationship with the cam, and the other end of the transmission rod establishes an installation relationship with the moving center axis.

[0022] Preferably, it also includes a tension spring, one end of which is hooked on the moving central axis, and the other end of the tension spring is fixed.

[0023] Preferably, the ring plate comprises an inner ring plate and an outer ring plate, and the inner ring plate and the outer ring plate are installed on the moving central shaft in an inclined manner.

[0024] Preferably, the inner ring plate and the outer ring plate are arranged on the moving central axis at an angle of 5°-15°, the inner ring plate is inclined downward in the horizontal direction, and the outer ring plate is inclined upward in the horizontal direction.

[0025] Preferably: the feeding screw conveyor comprises a feeding motor, a coupling, a bearing box, a silo stirring shaft, a stuffing box, a screw conveying shaft and a sleeve. The feeding motor, the bearing box and the stuffing box are arranged in sequence. The screw conveying shaft is rotatably installed in the bearing box. The screw conveying shaft establishes an installation relationship with the feeding motor through a coupling. The stuffing box is connected with a sleeve. The screw conveying shaft extends into the stuffing box and the sleeve. The silo stirring shaft extends into the stuffing box. The silo stirring shaft and the screw conveying shaft are respectively installed with a first gear and a second gear, and the first gear and the second gear are meshingly installed.

[0026] Preferably, the feed screw conveyor further comprises a connecting spring box, and the sleeve is installed in cooperation with the moving bed via the connecting spring box.

[0027] Preferably: it also includes a feeding electronic scale, and the feeding electronic scale is arranged at the lower side of the feeding screw conveyor.

[0028] Preferably: it also includes a feeding trolley, which is installed at the lower end of the feeding electronic scale.

[0029] The present invention has the following beneficial effects:

[0030] 1. Improvement and enhancement of existing processes

[0031] The existing hydrofluorination process has the disadvantages of low efficiency and generation of a large amount of difficult-to-treat secondary waste in tail gas treatment. The use of a baffled moving bed to recover hydrogen fluoride can improve and increase the utilization rate of the existing process system.

[0032] 2. Reduce the amount of fluorine-containing waste, which is beneficial to environmental protection

[0033] The hydrogen fluoride content in the tail gas of the hydrofluorination process is 20% (mass fraction). A large amount of fluorine-containing waste liquid is generated during tail gas elution. It is usually treated by lime neutralization. This method has a treatment efficiency of only about 30% and produces a large amount of secondary waste. After the hydrogen fluoride is recovered by the baffled moving bed, no fluorine-containing waste is generated, which is beneficial to environmental protection.

[0034] 3. It is conducive to energy saving and consumption reduction, and improves the economic efficiency of process operation.

[0035] Excess hydrogen fluoride in the hydrofluorination tail gas is not recycled, which affects the utilization rate of hydrogen fluoride in the hydrofluorination production process. The use of a baffled moving bed to recover hydrogen fluoride can improve the economy of the process operation.

[0036] 4. The present invention comprises a hydrogen fluoride recycling device composed of a feeding screw conveyor, a moving bed and a discharging screw conveyor. The uranium dioxide material is fed into the moving bed through the feeding screw conveyor, and hydrogen fluoride in the tail gas of the uranium dioxide hydrofluorination process is introduced into the moving bed in a countercurrent manner. A new type of baffle with vibration is arranged in the moving bed to make hydrogen fluoride fully contact with uranium dioxide, thereby increasing the absorption rate of uranium dioxide and hydrogen fluoride in the tail gas;

[0037] 5. The feed screw conveyor of the present invention not only realizes the conveyance of uranium dioxide particles to the moving bed, but also transmits the rotational force to the silo stirring shaft through the second gear and the first gear. The stirring teeth arranged on the silo stirring shaft continuously stir the uranium dioxide material falling into the stuffing box, so that the material in the stuffing box is in a loose state to avoid the occurrence of material jamming. Therefore, the feed screw conveyor of the present invention cleverly utilizes the mechanical transmission principle, has the characteristics of compact structure and diversified functions, and has the advantages of high transmission efficiency and reliable operation.

[0038] 6. The present invention has an ingenious structural design, a compact structure, complete functions, is easy to install and maintain, can effectively realize the recycling of hydrogen fluoride in the tail gas of the uranium oxide hydrofluorination process, and is suitable for promotion and use. BRIEF DESCRIPTION OF THE DRAWINGS

[0039] Figure 1 It is a layout diagram of a device for recycling hydrogen fluoride in the tail gas of the uranium dioxide hydrofluorination process;

[0040] Figure 2 is a structural schematic diagram of a specific implementation method three;

[0041] Figure 3 It is a schematic diagram of the plan structure of the feeding screw conveyor;

[0042] Figure 4 It is a cross-sectional view of the bed;

[0043] Figure 5 It is a structural diagram of the vibration mechanism;

[0044] Figure 6 yes Figure 4 The enlarged schematic diagram of point A in the middle;

[0045] In the figure, 1-feed hopper, 2-feed screw conveyor, 3-moving bed, 4-discharging screw conveyor, 5-bed, 6-moving central axis, 7-ring plate, 8-feed pipe, 9-inlet pipe, 10-outlet pipe, 11-discharge port, 12-duct, 13-dust collector, 14-discharging chamber, 15-upper cover, 16-vibration mechanism, 17-motor, 18-cam, 19-transmission rod, 20-tension spring, 21-inner ring plate , 22-outer ring plate, 23-feeding motor, 24-coupling, 25-bearing box, 26-silo stirring shaft, 27-stuffing box, 28-screw conveyor shaft, 29-sleeve, 30-connecting spring box, 31-conical inlet section, 32-first base, 33-first bearing seat, 34-stirring teeth, 35-second gear, 36-feeding electronic scale, 37-feeding trolley, 38-unloading telescopic hopper, 39-first gear. DETAILED DESCRIPTION

[0046] In order to make the purpose, technical scheme and advantages of the present invention clearer, the present invention is described below by the specific embodiments shown in the accompanying drawings. However, it should be understood that these descriptions are only exemplary and are not intended to limit the scope of the present invention. In addition, in the following description, the description of well-known structures and technologies is omitted to avoid unnecessary confusion of the concept of the present invention.

[0047] The connection mentioned in the present invention is divided into fixed connection and detachable connection. The fixed connection (i.e., non-detachable connection) includes but is not limited to conventional fixed connection methods such as folding connection, rivet connection, bonding connection and welding connection. The detachable connection includes but is not limited to conventional detachable methods such as threaded connection, snap connection, pin connection and hinge connection. When the specific connection method is not clearly defined, it is assumed that at least one connection method can always be found in the existing connection methods to achieve the function. Those skilled in the art can choose according to their needs. For example: welding connection is selected for fixed connection, and hinge connection is selected for detachable connection. Specific implementation method one:

[0049] Reference Figure 1As shown, this embodiment provides a device for recycling hydrogen fluoride in the tail gas of uranium dioxide hydrofluorination process, including a feed hopper 1, a feed screw conveyor 2, a moving bed 3 and a discharge screw conveyor 4. The feed screw conveyor 2 feeds the material in the feed hopper 1 into the moving bed 3, and the discharge screw conveyor 4 discharges the material in the moving bed 3.

[0050] In this embodiment, according to the actual operation situation of the uranium dioxide hydrofluorination process in the uranium conversion production field, the recovery of hydrogen fluoride in the tail gas of the uranium dioxide hydrofluorination process is carried out, and a hydrogen fluoride recovery test system in the tail gas of the uranium dioxide hydrofluorination process is established, which is applied to production practice, so as to achieve a recovery and reuse rate of hydrogen fluoride in the tail gas of the hydrofluorination process of ≥90%, improve the utilization rate of hydrogen fluoride, and achieve environmental protection requirements. Specifically, the uranium dioxide material in the feed hopper 1 is conveyed to the moving bed 3 by the feed screw conveyor 2, and the hydrogen fluoride in the tail gas of the uranium dioxide hydrofluorination process is input into the moving bed 3, so that the uranium dioxide is fully contacted with the hydrogen fluoride in the tail gas of the hydrofluorination process, and the absorption rate of uranium dioxide to the hydrogen fluoride in the tail gas is increased, and then the material in the moving bed 3 is discharged by the unloading screw conveyor 4.

[0051] Most of the tail gas in the hydrofluorination process is excess HF gas, containing a small amount of impurities such as water vapor and nitrogen. The working environment is a hydrogen fluoride atmosphere, so the bed must be corrosion-resistant. In addition, it needs to be heated to 200℃~230℃ during operation, so the material of the moving bed 3 must be resistant to high temperatures. After comprehensive consideration, Monel 400 is selected as the material of the bed. Monel 400 is a corrosion-resistant alloy with the largest dosage, the widest application, and excellent comprehensive performance. This alloy has excellent corrosion resistance in hydrofluoric acid and fluorine gas media, and also has excellent corrosion resistance to hot concentrated alkali solution. Specific implementation method 2:

[0053] Reference Figure 1 , Figure 2 and Figure 4 As shown, this embodiment provides a device for recycling hydrogen fluoride in tail gas of uranium dioxide hydrofluorination process, comprising a feed hopper 1, a feed screw conveyor 2, a moving bed 3 and a discharge screw conveyor 4, wherein the feed screw conveyor 2 feeds the material in the feed hopper 1 into the moving bed 3, and the discharge screw conveyor 4 discharges the material in the moving bed 3. The moving bed 3 is arranged in a vertical direction, and the feed screw conveyor 2 is connected and installed at the top of the moving bed 3, and the feed screw conveyor 2 feeds the material in the feed hopper 1 into the moving bed 3, and the discharge screw conveyor 4 is connected at the bottom of the moving bed 3, and the discharge screw conveyor 4 discharges the uranium dioxide and hydrogen fluoride materials in the moving bed 3 after full contact. Specific implementation method three:

[0055] Reference Figure 2 , Figure 3 As shown, a feed port with an inner hole of φ265mm and a height of 50mm is arranged at the center of the top of the feed hopper 1, and a tail gas outlet of DN40 (with a matching flange and a bellows joint) is arranged on the side; a discharge port is arranged at the bottom of the feed hopper 1, and the discharge port diameter of the feed hopper 1 is connected with the screw conveyor bin of the feed screw conveyor 2;

[0056] The feeding screw conveyor 2 includes a feeding motor 23 (variable frequency, equipped with local and remote control), a coupling 24, a bearing box 25, a silo stirring shaft 26, a stuffing box 27, a screw conveying shaft 28, a sleeve 29 and a connecting spring box 30. The feeding motor 23, the bearing box 25 and the stuffing box 27 are sequentially mounted on a first base 32. The screw conveying shaft 28 is rotatably mounted in the bearing box 25. The screw conveying shaft 28 establishes an installation relationship with the feeding motor 23 through the coupling 24. The stuffing box 27 is connected with a sleeve 29, and the sleeve 29 is installed in cooperation with the moving bed 3 through the connecting spring box 30. The spiral conveying shaft 28 extends into the stuffing box 27 and the sleeve 29. The stuffing box 27 has a straight section and a tapered inlet section 31 connected to the straight section. The silo stirring shaft 26 is installed on the first base 32 through a first bearing seat 33. The silo stirring shaft 26 extends into the stuffing box 27. The silo stirring shaft 26 is installed with stirring teeth 34. The stirring teeth 34 are arranged at the connection between the straight section and the tapered inlet section 31. The silo stirring shaft 26 and the spiral conveying shaft 28 are respectively installed with a first gear 39 and a second gear 35. The first gear 39 and the second gear 35 are installed in meshing. In this arrangement, the feed hopper 1 and the conical inlet section 31 of the stuffing box 27 are mounted in a flange manner, and the uranium dioxide material in the feed hopper 1 enters the stuffing box 27. Under the driving action of the feed motor 23, the screw conveying shaft 28 conveys the uranium dioxide in the stuffing box 27 into the moving bed 3 through the sleeve 29 and the connecting spring box 30. When the screw conveying shaft 28 rotates, the rotational force is transmitted to the silo stirring shaft 26 through the second gear 35 and the first gear 39. The stirring teeth 34 arranged on the silo stirring shaft 26 continuously stir the uranium dioxide material falling into the stuffing box 27, so that the material in the stuffing box 27 is stirred. The material is in a loose state to prevent the uranium dioxide material from depositing, causing the screw conveying shaft 28 to get stuck and causing the material transmission to fail. In this embodiment, in the process of realizing material transportation through the screw conveying shaft 28, the mechanical transmission principle is cleverly used to transmit the power of the screw conveying shaft 28 to the silo stirring shaft 26, and the uranium dioxide material in the loose filling box 27 is realized under the action of the silo stirring shaft 26. Therefore, unlike the prior art, the feeding screw conveyor 2 of this embodiment has the characteristics of compact structure and diversified functions, and by using this feeding screw conveyor 2, the material transmission efficiency and reliability are significantly improved.

[0057] In this embodiment, the connecting spring box 30 is used to connect the moving bed 3 and the sleeve 29 (the sleeve 29 is connected and installed on the stuffing box 27). The connecting spring box 30 can specifically be a corrugated conveying pipe. Under the action of the connecting spring box 30, the vibration force of the entire feed screw conveyor 2 is buffered, and the direct contact between the sleeve 29 and the moving bed 3 during the use / installation process is effectively avoided. The sleeve 29 and / or the feed port of the moving bed 3 is damaged by stress concentration, which indirectly increases the service life of the entire feed screw conveyor 2 and the entire hydrogen fluoride recycling device.

[0058] Preferably, a feed electronic scale 36 is installed under the feed screw conveyor 2 (or the first base 32). The feed electronic scale 36 has a load-bearing capacity of about 4 tons. The weight of uranium dioxide input into the moving bed 3 from the feed hopper 1 can be effectively weighed by the feed electronic scale 36, which is more beneficial to control the amount of uranium dioxide and hydrogen fluoride gas fed into the moving bed to ensure that the two are fully contacted in accordance with the required ratio.

[0059] Preferably, the lower end of the feeding electronic scale 36 is mounted on a feeding trolley 37, and the feeding trolley 37 is mounted under the feeding electronic scale and on a 8kg / m light rail; the load-bearing weight is about 5t; and the size of the trolley matches the feeding electronic scale. The feeding screw conveyor 2 and the feeding hopper 1 are driven to move by the feeding trolley 37 to improve the flexibility of uranium dioxide loading. For example, when the uranium dioxide in the feeding hopper 1 is used up, the mobile feeding trolley 37 can be replaced more efficiently, and then another feeding hopper 1 can be replaced to improve work efficiency.

[0060] Preferably, the moving bed 3 is installed with the unloading screw conveyor 4 through a unloading telescopic hopper 38. The unloading telescopic hopper 38 is a transition hopper between the moving bed 3 and the unloading screw conveyor 4. A DN100 material inlet pipe is arranged on the upper part of the hopper to connect with the discharge port 11 of the moving bed 3. A stuffing sealing box is arranged between the discharge port 11 and the telescopic hopper, which can achieve a certain amount of movement to alleviate the displacement of the moving bed during the heating process; the lower part of the unloading telescopic hopper 38 is connected with the silo of the unloading screw conveyor 4. The structure of the unloading screw conveyor 4 is consistent with that of the feeding screw conveyor 2, but the screw shaft and the sleeve are longer. The discharge port of the unloading screw conveyor 4 is arranged at the bottom and connected with the feed pipe of the unloading chamber 14.

[0061] Preferably, the discharge chamber 14 contains a feed pipe, the upper end of the feed pipe is connected to the discharge pipe of the discharge screw conveyor 4, and the lower end is connected to a spring box. A set of pneumatic clamping devices is provided and connected to the spring box outlet pipe, and the spring box outlet is connected to the 210L container inlet. The 210L container is placed on an electric trolley, and a set of electronic scales is provided at the bottom of the electric trolley light rail to control the filling amount of the 210L container; the whole set of devices is in the discharge chamber 14, a DN40 exhaust outlet is provided at the top of the discharge chamber 14, and a pair of pneumatic gates are provided in the discharge chamber 14; the length of the light rail outside the discharge chamber 14 is about 5000mm.

[0062] Preferably, the moving bed 3 comprises a bed body 5, a moving central axis 6 and a ring plate 7, the bed body 5 is provided with a feed pipe 8 and an air inlet pipe 9, the top of the bed body 5 is provided with an air outlet pipe 10, the bottom of the bed body 5 is provided with an outlet port 11, the feed screw conveyor 2 is in a matching installation relationship with the feed pipe 8, the outlet port 11 at the bottom of the bed body 5 is in a matching installation relationship with the unloading screw conveyor 4, the air outlet pipe 10 is connected to the dust collector 13 through a conduit 12, the dust collector 13: φ 400×800mm; cone length: 800mm; inlet and outlet: DN100 inlet is connected to the tail gas pipe of the moving bed, the outlet is connected to the on-site exhaust system, and the cone outlet DN40 pipe is connected to the tail gas pipeline of the feed hopper 1 with an acid-resistant rubber hose. The dust collector 13 performs dust removal on the tail gas flowing out of the moving bed. Specific implementation method four:

[0064] Reference Figure 1 , Figure 2 and Figure 4 As shown, this embodiment provides a device for recycling hydrogen fluoride in tail gas of uranium dioxide hydrofluorination process, comprising a feed hopper 1, a feed screw conveyor 2, a moving bed 3 and a discharge screw conveyor 4, wherein the feed screw conveyor 2 feeds the material in the feed hopper 1 into the moving bed 3, and the discharge screw conveyor 4 discharges the material in the moving bed 3, wherein the moving bed 3 comprises a bed body 5, a moving central axis 6 and a ring plate 7, the bed body 5 is provided with a feed pipe 8 and an air inlet pipe 9, the top of the bed body 5 is provided with an air outlet pipe 10, the bottom of the bed body 5 is provided with a discharge port 11, the feed screw conveyor 2 establishes a matching installation relationship with the feed pipe 8, the discharge port 11 at the bottom of the bed body 5 establishes a matching installation relationship with the discharge screw conveyor 4, a moving central axis 6 is provided in the bed body 5, and a ring plate 7 is arranged on the moving central axis 6, the bed body 5 is a vertical chamber, and the bed body 5 is circular, square, rectangular, rhombus, etc.;

[0065] In this embodiment, the bed 5 is a cylindrical cavity, and a feed pipe 8 and an air inlet pipe 9 are provided on the bed 5. The air inlet pipe 9 is below the feed pipe 8. The uranium dioxide material enters the cavity from the feed pipe 8, and the hydrogen fluoride in the tail gas of the uranium dioxide hydrofluorination process enters the bed 5 in a countercurrent manner from the air inlet pipe 9. In the bed 5, the tail gas of the uranium conversion uranium dioxide process enters the moving bed 3 from the lower end of the bed 5, and countercurrently contacts with the uranium dioxide entering from the feed pipe 8 at the upper end of the moving bed 3. When contacting, the uranium dioxide falls downward and fully collides / contacts with the hydrogen fluoride flowing upward, thereby improving the absorption rate of the uranium dioxide to the hydrogen fluoride in the tail gas.

[0066] In addition, a moving central shaft 6 is provided in the bed body 5, and a ring plate 7 is arranged on the moving central shaft 6. Under the action of the moving central shaft 6 and the ring plate 7, the uranium dioxide entering the bed body 5 from the feed pipe 8 slowly falls, thereby prolonging the contact time between the uranium dioxide particles and the tail gas of the hydrofluorination process.

[0067] It should be further explained that those skilled in the art can change the arrangement of the feed pipe 8 and the air inlet pipe 9 on the bed 5 in any way, as long as it does not exceed the spirit of this patent, it is within the protection scope of this patent;

[0068] For example:

[0069] The feed pipe 8 and the air intake pipe 9 are arranged on the same side of the bed 5;

[0070] The feed pipe 8 and the air intake pipe 9 are arranged on different sides of the bed 5;

[0071] The feed pipe 8 is arranged above the center line of the bed 5 , and the air intake pipe 9 is arranged below the center line of the bed 5 . Specific implementation method five:

[0073] Reference Figure 1 , Figure 4As shown, different from the fourth specific embodiment, the feed pipe 8 is installed on the bed 5 in an inclined manner, and a solid feed pipe 8 is arranged on the upper side of the bed. It is an inclined tube, and the inclination angle formed by the feed pipe 8 and the axis of the bed 5 is 20-60°, and the optimal inclination angle is 30°. The feed pipe 8 is installed on the bed 5 in an inclined manner, so that the uranium dioxide particles can enter the bed 5 in an incision manner, making the material entering the bed 5 smoother. In addition, the feed pipe 8 is installed on the bed 5 in an inclined manner, rather than being directly fixed above the bed 5. The purpose is to avoid that when the feed pipe 8 is arranged directly above the bed 5, the uranium dioxide particles entering the bed 5 from the feed pipe 8 fall vertically into the inside of the bed 5, so that the uranium dioxide will be deposited on the ring plate 7 during its falling process, causing the uranium dioxide particles to be stuck on the ring plate 7, that is, the "dead bed" phenomenon. Therefore, the feed pipe 8 is installed on the bed 5 in an inclined manner and has the effect of buffering the entry of uranium dioxide particles, so that it can continuously and slowly enter the bed, maintain a good feeding state, and meet the requirements of secondary contact between uranium dioxide and hydrogen fluoride. Specific implementation method six:

[0075] Reference Figure 1 , Figure 4 and Figure 5 As shown, different from the fourth embodiment, an upper cover 15 is installed on the top of the bed body 5, and the upper end of the moving central shaft 6 passes through the upper cover 15 and is connected to a vibration mechanism 16. The vibration mechanism 16 can be an electric cylinder, a hydraulic cylinder, an electric telescopic rod, a motor, a cam reciprocating motion mechanism, or a mechanism that can drive the moving central shaft to complete linear reciprocating motion.

[0076] Under the action of the vibration mechanism 16, the vibration mechanism 16 drives the moving central shaft 6 to perform linear reciprocating motion in the bed body 5. Driven by the moving central shaft 6, the ring plate 7 vibrates up and down at a certain frequency in the bed body 5. In this way, the contact time between the uranium dioxide particles and the tail gas of the hydrofluorination process is prolonged, and the uranium dioxide particles are prevented from adhering to the baffle plate to cause a "dead bed" phenomenon. Specific implementation method seven:

[0078] Reference Figure 5As shown, on the basis of the specific embodiment 6, the vibration mechanism 16 includes a motor 17, a cam 18 and a transmission rod 19, wherein the cam 18 is an eccentric rotating cam, the cam 18 is installed on the output shaft of the motor 17, the transmission rod 19 is connected to the fulcrum O, one end of the transmission rod 19 is installed with the cam 18, and the other end of the transmission rod 19 is installed with the moving central shaft 6. In this way, the motor 17 drives the cam 18 to rotate, and under the action of the cam 18, the transmission rod 19 moves with O as the fulcrum, and the transmission rod 19 drives the moving central shaft 6 to move up and down. The ring plate 7 is driven by the central shaft to vibrate up and down in the bed body at a certain frequency, which further prolongs the contact time between the solid particles and the hydrogen fluoride tail gas of the hydrofluorination process, thereby increasing the absorption rate of uranium dioxide to hydrogen fluoride in the tail gas. In addition, under the action of the vibration mechanism 16 of this embodiment, the moving central shaft 6 drives the ring plate 7 to vibrate at a certain frequency, which prevents the uranium dioxide particles from sticking to the ring plate and causing the "dead bed" phenomenon. Specific implementation eight:

[0080] Reference Figure 5 As shown, different from the specific embodiment seven, a tension spring 20 is also installed on the moving center shaft 6, and the other end of the tension spring 20 is fixed, for example, fixed on the beam of the factory building (at point H). By setting the tension spring 20, the moving center shaft 6 has a rebound force during the reciprocating motion in the vertical direction. The benefits of this rebound force are: (1) it can assist the moving center shaft 6 to rise, increase the vibration frequency of the vibration mechanism 16, and thereby increase the contact rate between uranium dioxide and hydrogen fluoride in the bed 5; (2) under the action of the tension spring 20 hooked at point H, the gravity on the moving center shaft 6 can be reduced; (3) under the action of the tension spring 20, it can assist in reducing the load of the motor 17 and increase the service life of the motor 17. Specific implementation method nine:

[0082] Reference Figure 6 As shown, the ring plate 7 includes an inner ring plate 21 and an outer ring plate 22 , and the inner ring plate 21 and the outer ring plate 22 are installed on the moving central shaft 6 in an inclined manner.

[0083] The inner ring plate 21 and the outer ring plate 22 constitute a baffle, and a pair of the inner ring plate 21 and the outer ring plate 22 is a level. The entire moving central shaft is equipped with several levels of baffles, for example, 20 levels, wherein the inner ring plate 21 and the outer ring plate 22 are arranged on the moving central shaft 6 at an angle of 10°, the inner ring plate 21 is tilted downward at an angle of 10° in the horizontal direction, and the outer ring plate 22 is tilted upward at an angle of 10° in the horizontal direction; the inner ring plate and the outer ring plate are connected, and the baffle structure increases the residence time of the material in the reactor, and the tilt angle of 10° is equal to the value of the material accumulation angle, so as to avoid the material from falling smoothly. The moving central shaft drives the baffle connected thereto to vibrate, and the material jumps and falls step by step, which effectively prolongs the reaction time and is suitable for most materials with poor fluidity to react.

[0084] It should be noted that the terms used herein are only for describing specific embodiments and are not intended to limit the exemplary embodiments according to the present application. As used herein, unless the context clearly indicates otherwise, the singular form is also intended to include the plural form. In addition, it should be understood that when the terms "comprise" and / or "include" are used in this specification, it indicates the presence of features, steps, operations, devices, components and / or combinations thereof.

[0085] Unless otherwise specifically stated, the relative arrangement of the parts and steps described in these embodiments, numerical expressions and numerical values ​​do not limit the scope of the present invention. At the same time, it should be understood that, for ease of description, the sizes of the various parts shown in the accompanying drawings are not drawn according to the actual proportional relationship. The technology, method and equipment known to ordinary technicians in the relevant field may not be discussed in detail, but in appropriate cases, the technology, method and equipment should be regarded as a part of the authorization specification. In all examples shown and discussed here, any specific value should be interpreted as being merely exemplary, rather than as a limitation. Therefore, other examples of exemplary embodiments may have different values. It should be noted that similar reference numerals and letters represent similar items in the following drawings, so once a certain item is defined in an accompanying drawing, it does not need to be further discussed in subsequent drawings.

[0086] In the description of the present invention, it is necessary to understand that the directions or positional relationships indicated by directional words such as "front, back, up, down, left, right", "lateral, vertical, perpendicular, horizontal" and "top, bottom" are usually based on the directions or positional relationships shown in the drawings. They are only for the convenience of describing the present invention and simplifying the description. Unless otherwise specified, these directional words do not indicate or imply that the devices or elements referred to must have a specific direction or be constructed and operated in a specific direction. Therefore, they cannot be understood as limiting the scope of protection of the present invention. The directional words "inside and outside" refer to the inside and outside relative to the contours of each component itself.

[0087] For ease of description, spatially relative terms such as "above", "above", "on the upper surface of", "above", etc. may be used here to describe the spatial positional relationship between a device or feature and other devices or features as shown in the figure. It should be understood that spatially relative terms are intended to include different orientations of the device in use or operation in addition to the orientation described in the figure. For example, if the device in the accompanying drawings is inverted, the device described as "above other devices or structures" or "above other devices or structures" will be positioned as "below other devices or structures" or "below other devices or structures". Thus, the exemplary term "above" can include both "above" and "below". The device can also be positioned in other different ways (rotated 90 degrees or in other orientations), and the spatially relative descriptions used here are interpreted accordingly.

[0088] It should be noted that the terms "first", "second", etc. in the specification and claims of the present application and the above-mentioned drawings are used to distinguish similar objects, and are not necessarily used to describe a specific order or sequence. It should be understood that the numbers used in this way can be interchanged where appropriate, so that the embodiments of the present application described herein can be implemented in an order other than those illustrated or described herein.

[0089] It should be noted that in the above embodiments, as long as the technical solutions are not contradictory, they can be arranged and combined, and those skilled in the art can exhaust all possibilities based on the mathematical knowledge of arrangement and combination. Therefore, the present invention will no longer describe the technical solutions after arrangement and combination one by one, but it should be understood that the technical solutions after arrangement and combination have been disclosed by the present invention.

[0090] This implementation is only an exemplary description of this patent and does not limit its protection scope. Those skilled in the art may also make partial changes to it, as long as they do not exceed the spirit of this patent, they are all within the protection scope of this patent.

Claims

1. A device for recycling hydrogen fluoride in tail gas of uranium dioxide hydrofluorination process, characterized in that: The invention comprises a feed hopper (1), a feed screw conveyor (2), a moving bed (3) and a discharge screw conveyor (4), wherein the feed screw conveyor (2) delivers the material in the feed hopper (1) into the moving bed (3), and the discharge screw conveyor (4) discharges the material in the moving bed (3); The movable bed (3) comprises a bed body (5), a movable central shaft (6) and a ring plate (7); the bed body (5) is provided with a feed pipe (8) and an air inlet pipe (9); the top of the bed body (5) is provided with an air outlet pipe (10); the bottom of the bed body (5) is provided with a discharge port (11); the feed screw conveyor (2) is in a matching installation relationship with the feed pipe (8); the discharge port (11) at the bottom of the bed body (5) is in a matching installation relationship with the discharge screw conveyor (4); a movable central shaft (6) is provided in the bed body (5); and a ring plate (7) is arranged on the movable central shaft (6); The feed pipe (8) and the air intake pipe (9) are both installed on the side wall of the bed (5), the feed pipe (8) is arranged at the upper part of the bed (5), and the air intake pipe (9) is arranged at the lower part of the bed (5); An upper cover (15) is installed on the top of the bed (5), and the upper end of the moving central shaft (6) passes through the upper cover (15) and is connected to a vibration mechanism (16); The ring plate (7) comprises an inner ring plate (21) and an outer ring plate (22), and the inner ring plate (21) and the outer ring plate (22) are installed on the moving central shaft (6) in an inclined manner; The inner ring plate (21) and the outer ring plate (22) are arranged on the moving central axis (6) at an angle of 5°-15°, the inner ring plate (21) is inclined downward in the horizontal direction, and the outer ring plate (22) is inclined upward in the horizontal direction; The vibration mechanism includes a motor, a cam and a transmission rod. The cam is an eccentric rotating cam. The cam is installed on the output shaft of the motor. The transmission rod is connected to the fulcrum O. One end of the transmission rod establishes an installation relationship with the cam, and the other end of the transmission rod establishes an installation relationship with the moving center axis.

2. The device for recycling hydrogen fluoride in tail gas of uranium dioxide hydrofluorination process according to claim 1, characterized in that: The air outlet pipe (10) is connected to the dust collector (13) through a conduit (12).

3. The device for recycling hydrogen fluoride in tail gas of uranium dioxide hydrofluorination process according to claim 1, characterized in that: The output end of the unloading screw conveyor (4) is connected to the unloading chamber (14).

4. The device for recycling hydrogen fluoride in tail gas of uranium dioxide hydrofluorination process according to claim 1, characterized in that: The moving bed (3) is installed with the unloading screw conveyor (4) via a unloading telescopic hopper (38).

5. The device for recycling hydrogen fluoride in tail gas of uranium dioxide hydrofluorination process according to claim 4, characterized in that: The upper part of the discharging telescopic hopper (38) is provided with a material inlet pipe connected to the discharge port (11) of the moving bed (3), a stuffing sealing box is provided between the discharge port and the discharging telescopic hopper, and the lower part of the discharging telescopic hopper (38) is connected to the material bin of the discharging screw conveyor (4).

6. The device for recycling hydrogen fluoride in tail gas of uranium dioxide hydrofluorination process according to claim 1, characterized in that: The feed pipe (8) is arranged and installed on the bed (5) in an inclined manner.

7. The device for recycling hydrogen fluoride in tail gas of uranium dioxide hydrofluorination process according to claim 6, characterized in that: The inclination angle formed by the feed pipe (8) and the axis of the bed (5) is 20-60°.

8. The device for recycling hydrogen fluoride in tail gas of uranium dioxide hydrofluorination process according to claim 1, characterized in that: The feeding screw conveyor (2) comprises a feeding motor (23), a coupling (24), a bearing box (25), a silo stirring shaft (26), a stuffing box (27), a screw conveying shaft (28), and a sleeve (29). The feeding motor (23), the bearing box (25), and the stuffing box (27) are arranged in sequence. The screw conveying shaft (28) is rotatably mounted in the bearing box (25). The screw conveying shaft (28) is installed with the feeding motor (23) through the coupling (24). The stuffing box (27) is connected with a sleeve (29). The screw conveying shaft (28) extends into the stuffing box (27) and the sleeve (29). The silo stirring shaft (26) extends into the stuffing box (27). The silo stirring shaft (26) and the screw conveying shaft (28) are respectively installed with a first gear (39) and a second gear (35). The first gear (39) and the second gear (35) are meshed and installed.

9. The device for recycling hydrogen fluoride in tail gas of uranium dioxide hydrofluorination process according to claim 8, characterized in that: The feeding screw conveyor (2) also includes a connecting spring box (30), and the sleeve (29) is installed in cooperation with the moving bed (3) via the connecting spring box (30).

10. The device for recycling hydrogen fluoride in tail gas of uranium dioxide hydrofluorination process according to claim 8 or 9, characterized in that: It also includes a feeding electronic scale (36), which is arranged on the lower side of the feeding screw conveyor (2).

11. The device for recycling hydrogen fluoride in tail gas of uranium dioxide hydrofluorination process according to claim 10, characterized in that: The utility model also comprises a feeding trolley (37), which is installed at the lower end of the feeding electronic scale (36).

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