High-activity uranium trioxide production method and equipment for treating large-flux uranyl nitrate

Abstract

The invention discloses a high-activity uranium trioxide production method and equipment for treating large-flux uranyl nitrate, and the method comprises the following steps: introducing fuel gas into a combustion chamber through a gas supply system, and enabling the fuel gas to be subjected to combustion reaction to generate high-temperature gas; high-temperature gas is introduced into the reaction chamber, a uranyl nitrate solution is conveyed into the reaction chamber, the uranyl nitrate solution makes contact with the high-temperature gas, then a thermal decomposition reaction is conducted, and powder mixed gas is obtained; powder mixed gas in the reaction chamber is conveyed to a powder receiving hopper through an L discharging valve and filtered through a filtering device, then the gas is introduced into a tail gas purification system to recycle nitric acid, nitric oxide in tail gas is converted into nitrogen and then discharged, the powder is led out to a collecting device after being settled, and a uranium trioxide finished product is obtained. The uranium trioxide product prepared by the method is large in specific surface area, high in activity, large in treatment flux, high in tail gas treatment efficiency and good in effect, and can solve the problems that high-flux uranyl nitrate cannot be treated and nitric oxide severely exceeds the standard in the prior art.

Description

Technical Field

[0001] The invention relates to the technical field of denitration, and in particular to a method and equipment for producing high-activity uranium trioxide for treating large-flux uranyl nitrate. Background Art

[0002] In the field of nuclear fuel production, U 3 O 8 , UO 3 and UO 2 There are three important uranium oxides with practical value. Among them, UO 3 As an important intermediate product in the nuclear fuel cycle system, its preparation technology occupies a very important position in the nuclear fuel cycle process and is widely used.

[0003] In the nuclear fuel cycle system, uranium ore or spent fuel components undergo a series of treatments to obtain uranyl nitrate solution, which can then be thermally decomposed to produce UO 3 , produced by UO 3 Sent to the nuclear fuel plant to prepare nuclear fuel.

[0004] At present, most of the dry denitration processes are used to process uranyl nitrate into uranium oxide. Some nuclear chemical plants use fluidized bed denitration processes. However, the specific surface area of ​​uranium trioxide produced by fluidized bed denitration is small, most of which are less than 2m 2 / g. Under the process conditions of fluidized bed calciner, the fluorination process has a great influence on the feed UO 3 The reactivity of UO has certain requirements. 3 When the specific surface area of ​​the fluidized bed calciner is greater than a certain value, the performance of the fluidized bed calciner product can meet the requirements. 3 The product has a low specific surface area, which makes its reactivity poor and limits its application.

[0005] In addition, since the thermal decomposition of uranyl nitrate is an endothermic reaction, a large amount of heat is required for the reaction. The existing technology cannot increase the processing flux, and there are problems such as incomplete raw material reaction, low production efficiency, and small production scale. It cannot be used on a large scale and cannot be applied to industrial-grade production. Moreover, increasing the processing flux will correspondingly produce more nitrogen oxide waste gas due to thermal decomposition. The processing efficiency of the existing technology is low, and there are problems such as serious excessive nitrogen oxides in the tail gas. At the same time, since the filter material used in the existing tail gas treatment system has a coarse diameter, it is difficult to filter out fine UO 3 The filtration effect of the powder is not ideal, and there will be more UO 3 The powder passes through the filter material, and there are problems such as large filtration resistance and high energy consumption. Summary of the invention

[0006] The technical problem to be solved by the present invention is to provide a method and equipment for producing high-activity uranium trioxide for treating large-flux uranyl nitrate in view of the above-mentioned deficiencies in the prior art. The prepared uranium trioxide product has a large specific surface area and high activity, and has a large treatment flux, high tail gas treatment efficiency and good effect, and can solve the problem that the prior art cannot treat high-flux uranyl nitrate and the problem that nitrogen oxides seriously exceed the standard.

[0007] The technical solution of the present invention to solve the above technical problems is:

[0008] According to a first aspect of the present invention, there is provided a method for producing high-activity uranium trioxide by treating a large flux of uranyl nitrate, comprising:

[0009] (1) introducing gas into the combustion chamber through a gas supply system to cause the gas to undergo a combustion reaction and generate high-temperature gas, wherein the gas supply system includes a storage tank, a compressor, an unloading module, a gasification pressure regulating device and a pressure reducing valve group, the storage tank is connected to the compressor through a first pipeline, the compressor is connected to the unloading module through a second pipeline, the unloading module is connected to the storage tank through a third pipeline, the gasification pressure regulating device is connected to the storage tank through a fourth pipeline, the pressure reducing valve group is connected to the gasification pressure regulating device, and the combustion chamber is connected to the pressure reducing valve group;

[0010] (2) introducing high temperature gas into the reaction chamber and delivering uranyl nitrate solution into the reaction chamber, so that the uranyl nitrate solution and the high temperature gas come into contact with each other and undergo a thermal decomposition reaction to generate uranium trioxide and nitrogen oxides, thereby obtaining a powder mixed gas;

[0011] (3) The powder mixed gas in the reaction chamber is transported to the powder receiving hopper through the L discharge valve. After being filtered by the filter device, the gas is introduced into the tail gas purification system to recover nitric acid and then the nitrogen oxides in the tail gas are converted into nitrogen gas before being discharged. The powder is discharged to the collection device after sedimentation to obtain a finished uranium trioxide product. The tail gas purification system specifically includes an absorption tower, an ammonia spraying device, a catalyst bed, a booster fan, a tail gas detection device and a chimney. The absorption tower is connected to the filter device, the ammonia spraying device is connected to the absorption tower, the catalyst bed is connected to the ammonia spraying device, the booster fan is connected to the catalyst bed, and the tail gas detection device and the chimney are respectively connected to the booster fan.

[0012] Optionally, the fuel gas is liquefied petroleum gas.

[0013] Optionally, the uranyl nitrate solution is sprayed into the reaction chamber in a spray manner using an atomizing nozzle.

[0014] Optionally, the aperture of the atomizing nozzle is 0.2-1.2 mm, and the atomizing angle is 40-65°.

[0015] Optionally, the feed concentration of the uranyl nitrate solution is 1000-2000 g / L, the feed flow rate is 200-400 L / h, and the nitric acid concentration in the uranyl nitrate solution is 3-5 mol / L.

[0016] Optionally, the reaction temperature in the reaction chamber is controlled to be 440-500°C, and the pressure in the reaction chamber is controlled to be -5kPa.

[0017] Optionally, the filtration device uses a high-performance filtration composite membrane as a filter element, and the high-performance filtration composite membrane is prepared in the following manner:

[0018] preparing a composite spinning solution;

[0019] Ultrasonic treatment is performed on the composite spinning solution to obtain a pretreated composite spinning solution;

[0020] The spinning solution is subjected to electrostatic spinning to obtain a composite spinning membrane;

[0021] The composite spinning membrane is dried at 80° C. for 20 hours to obtain the high-performance filtration composite membrane.

[0022] Optionally, the composite spinning solution is prepared in the following manner:

[0023] Adding polystyrene resin to an organic solvent, stirring and mixing evenly, then adding nanocomposite material and N, N', N"-tris[1-(methoxymethyl)propyl]benzene-1,3,5-tricarboxamide respectively, adjusting the temperature to 70°C, keeping the temperature and stirring for 30 minutes, and then performing ultrasonic dispersion for 5 minutes to obtain the composite spinning solution;

[0024] The organic solvent is DMF; the mixed mass ratio of polystyrene resin and DMF is 12-15:100; the mixed mass ratio of polystyrene resin, nanocomposite material and N,N',N"-tris[1-(methoxymethyl)propyl]benzene-1,3,5-tricarboxamide is 40:1-3:4-5.

[0025] Optionally, the nanocomposite material is prepared in the following manner:

[0026] The nano-bentonite was added into ethanol and dispersed by ultrasonic for 10 min to obtain a dispersion;

[0027] Adding coal slag powder and lignin into the dispersion, stirring for 30 minutes, and drying to obtain a mixture;

[0028] The mixed material is added into a tubular furnace, heated and calcined for 3 hours under the protection of an inert atmosphere, and then naturally cooled to room temperature to obtain the nanocomposite material;

[0029] The mass ratio of the nano-bentonite to ethanol is 1:5-6; the mass ratio of the nano-bentonite to coal slag powder to lignin is 10:1-2:3-5; the inert atmosphere is nitrogen; and the heating and calcining temperature is 820-860°C.

[0030] Optionally, the voltage of the electrospinning is 16-18 kV, the receiving distance is fixed at 18 cm, the ambient temperature of the spinning room is 25° C., and the humidity is 35%.

[0031] Optionally, the absorption tower comprises a plurality of absorption towers connected in series, and each absorption tower is provided with Y-250 type 304 stainless steel structured packing.

[0032] Optionally, the catalyst bed is V 2 O 5 / TiO 2 Catalytic denitrification catalyst.

[0033] Optionally, the method further comprises:

[0034] Before the gas filtered by the filter device enters the absorption tower, the gas filtered by the filter device is first condensed, the condensed non-condensable gas is heat exchanged with the gas after the catalyst bed reaction, and then the non-condensable gas after the heat exchange is passed into the absorption tower to form nitric acid;

[0035] Before the gas treated in the absorption tower enters the catalyst bed, the tail gas after the nitric acid is recovered in the absorption tower is first heated, and then introduced into the ammonia injection device to mix with ammonia and then introduced into the catalyst bed for catalytic reaction to form nitrogen.

[0036] According to a second aspect of the present invention, there is provided a high-activity uranium trioxide production device for processing large-flux uranyl nitrate, comprising a feeding system, a reaction system, a gas supply system, and an exhaust gas purification system, wherein:

[0037] The feeding system is connected to the reaction system and is used to deliver the uranyl nitrate solution to the reaction system;

[0038] The gas supply system is connected to the reaction system and is used to introduce gas into the reaction system. It specifically includes a storage tank, a compressor, an unloading module, a gasification pressure regulating device and a pressure reducing valve group. The storage tank is connected to the compressor through a first pipeline, the compressor is connected to the unloading module through a second pipeline, the unloading module is also connected to the storage tank through a third pipeline, the gasification pressure regulating device is connected to the storage tank through a fourth pipeline, and the pressure reducing valve group is connected to the gasification pressure regulating device;

[0039] The reaction system is used to receive fuel gas and uranyl nitrate solution and to generate high-temperature gas by combustion reaction of the fuel gas, so that the uranyl nitrate solution and the high-temperature gas are contacted to perform thermal decomposition reaction to generate uranium trioxide and nitrogen oxides. The reaction system specifically comprises a combustion chamber, a reaction chamber, a powder receiving hopper, a filtering device and a collecting device. The combustion chamber is connected to the pressure reducing valve group in the gas supply system, the reaction chamber is connected to the combustion chamber and the feeding system respectively, the reaction chamber is provided with an L discharge valve, the powder receiving hopper is connected to the reaction chamber through the L discharge valve, and the filtering device and the collecting device are connected to the powder receiving hopper respectively;

[0040] The exhaust gas purification system is connected to the reaction system and is used for deeply purifying the exhaust gas discharged from the reaction system. It specifically includes an absorption tower, an ammonia spraying device, a catalyst bed, a booster fan, an exhaust gas detection device and a chimney. The absorption tower is connected to the filtering device in the reaction system, the ammonia spraying device is connected to the absorption tower, the catalyst bed is connected to the ammonia spraying device, the booster fan is connected to the catalyst bed, and the exhaust gas detection device and the chimney are respectively connected to the booster fan.

[0041] Optionally, the gas supply system further includes a release module, which is connected to the storage tank and has a temperature-controlled gasifier disposed therein.

[0042] Optionally, an atomizing nozzle is provided at the tail end of the feeding system so that the transported uranyl nitrate solution enters the reaction chamber in a spray manner.

[0043] Optionally, the aperture of the atomizing nozzle is 0.8 mm and the atomizing angle is 45°.

[0044] Optionally, the filtering device uses the high-performance filtering composite membrane described in claim 7 as a filtering element, and the specific surface area of ​​the high-performance filtering composite membrane is 8-20m 2 / g.

[0045] Optionally, the absorption tower includes a first absorption tower, a second absorption tower, a third absorption tower and a fourth absorption tower, and the first absorption tower, the second absorption tower, the third absorption tower and the fourth absorption tower are arranged in series in sequence, the first absorption tower is connected to the filtering device in the reaction system, the fourth absorption tower is connected to the ammonia injection device, and the first absorption tower, the second absorption tower, the third absorption tower and the fourth absorption tower are all provided with Y-250 type 304 stainless steel structured packing.

[0046] Optionally, the catalyst bed is V 2 O 5 / TiO 2 Catalytic denitrification catalyst.

[0047] Optionally, the tail gas purification system further includes a condenser, a heat exchanger and a heating furnace, wherein:

[0048] The absorption tower is connected to the outlet end of the first channel of the heat exchanger, the inlet end of the first channel of the heat exchanger is connected to the condenser, and the condenser is connected to the filtering device in the reaction system;

[0049] The ammonia spraying device is connected to a heating furnace, and the heating furnace is further connected to an absorption tower.

[0050] Optionally, the heating furnace is connected to a pressure reducing valve group in a gas supply system to allow the introduction of fuel gas.

[0051] Beneficial effects:

[0052] The high-activity uranium trioxide production method and equipment for processing large-flux uranyl nitrate of the present invention are mainly used in uranium purification process and post-processing process. Compared with the prior art, by optimizing the full-process layout of the gas supply system-reaction system and tail gas purification system, the obtained uranium trioxide product has a large specific surface area and high activity, and has a large processing flux, high tail gas treatment efficiency and good effect. It can achieve a processing capacity of more than 5 tons of uranium / day, can be adapted to future thousand-ton nuclear chemical plants and further improve uranium conversion capacity, solve the problems that the prior art cannot process high-flux uranyl nitrate and serious excess of nitrogen oxides, and is the first time to propose a full-process flame denitrification process for the nuclear fuel cycle system, which is of great significance to the sustainable development of nuclear energy. Specifically:

[0053] 1. By optimizing the gas supply system, the circuit is simple, the operation is convenient, the safety is high, and it can provide stable energy raw materials. In addition, it can also provide gas for the reaction system and the tail gas purification system at the same time, so that each reaction process can be carried out continuously and the processing efficiency is improved;

[0054] 2. By optimizing the reaction conditions of the gas supply system and the reaction system, it is possible to make real-time adjustments according to the heat required for the thermal reaction to maximize the reaction efficiency, thereby providing a guarantee for the high-throughput uranium conversion capacity of the entire production system. Multiple solutions are being developed simultaneously to jointly improve the processing throughput and achieve a processing capacity of more than 5 tons of uranium per day, thereby increasing the production scale, which is not possible with existing technologies;

[0055] 3. By setting the L discharge valve, the reaction in the reaction chamber can be continued, the utilization rate of the heat released by the combustion of the gas can be improved, the reaction efficiency and reaction degree can be improved, and the reaction can be completed. Compared with the prior art using a disc valve for discharge, it can avoid the problem that the incomplete reaction of some uranyl nitrates due to the limited contact time between the high-temperature gas and the reaction raw materials (especially after the processing flux is increased, this problem will be more significant), resulting in a significant reduction in product quality, etc.;

[0056] 4. By optimizing the filtering device, the interception capability of uranium trioxide particles carried in the tail gas can be improved, so as to adapt to the problem of more uranium trioxide particles and powder in the tail gas caused by increasing the production scale, and prevent UO3 powder from being discharged with the gas, causing waste of resources, so that the radioactivity level of the waste liquid generated by the whole system is less than 50μgU / L, which meets the domestic emission standards;

[0057] 5. By optimizing the tail gas purification system and adopting wet absorption coupled with dry denitration technology, the purification effect of nitrogen oxides can be greatly improved and ammonia escape can be controlled, thereby adapting to the problem of more nitrogen oxide waste gas generated after high-throughput treatment, and realizing the deep purification of ultra-high concentration nitrogen oxides produced by high-throughput uranyl nitrate thermal decomposition, which can not only recover nitric acid but also meet the tail gas emission standards;

[0058] 6. By using cheap liquefied petroleum gas as fuel, costs can be reduced. At the same time, by controlling the combustion of fuel gas and oxygen in the combustion chamber, process energy consumption can also be reduced;

[0059] 7. By optimizing the atomizing nozzle and using the spray method to allow the uranyl nitrate solution to enter the reaction chamber, higher reaction efficiency can be achieved, the specific surface area of ​​the UO3 product particles can be increased, and higher reaction activity can be maintained, thereby greatly broadening the application range of the product. BRIEF DESCRIPTION OF THE DRAWINGS

[0060] Figure 1 A schematic diagram of a method and apparatus for producing high-activity uranium trioxide by processing large-flux uranyl nitrate in an embodiment of the present invention;

[0061] Figure 2 is a schematic diagram of a gas supply system in an embodiment of the present invention;

[0062] Figure 3 is a schematic diagram of an exhaust gas purification system in an embodiment of the present invention;

[0063] Figure 4 This is a general assembly diagram of a high-activity uranium trioxide production device for processing a large flux of uranyl nitrate in an embodiment of the present invention.

[0064] In the figure: 1. Feeding system; 2-Reaction chamber; 3. Combustion chamber; 4. Gas supply system;

[0065] 5. Cooling system; 6. Exhaust gas purification system; 7. Filter device; 8. Powder receiving hopper;

[0066] 9. Collection device; 10. L discharge valve;

[0067] 01, unloading module; 02, compressor; 03, storage tank; 04, third pipeline; 05, second gasification pressure regulating device; 051, first gasification pressure regulating device; 06, second pressure reducing valve group; 061, first pressure reducing valve group; 071, first output terminal; 07, second output terminal; 08, release module; 09, second unloading module;

[0068] 20. Exhaust gas inlet; 21. Booster fan; 22. Control valve; 23. Heat exchanger;

[0069] 24. First absorption tower; 25. Second absorption tower; 26. Third absorption tower; 27. Fourth absorption tower; 28. Heating furnace; 29. ​​Ammonia inlet; 210. Ammonia injection device; 211. Catalyst bed; 212. Exhaust gas detection device; 213. Chimney; 215. Condenser. DETAILED DESCRIPTION

[0070] In order to enable those skilled in the art to better understand the technical solution of the present invention, the technical solution of the present invention will be clearly and completely described below in conjunction with the drawings in the present invention. Obviously, the described embodiments are part of the embodiments of the present invention, not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without making creative work belong to the protection scope of the present invention.

[0071] Regarding UO in the existing technology 3 The specific surface area is small, the reaction activity is poor, the processing flux cannot be improved, the raw material reaction is incomplete, the production efficiency is low, the production scale is small, the tail gas treatment efficiency is low, and the nitrogen oxides are seriously exceeded. The present invention provides a high-activity uranium trioxide production method for treating large-flux uranyl nitrate, comprising:

[0072] (1) introducing gas into the combustion chamber through a gas supply system to cause the gas to undergo a combustion reaction and generate high-temperature gas, wherein the gas supply system includes a storage tank, a compressor, an unloading module, a gasification pressure regulating device and a pressure reducing valve group, the storage tank is connected to the compressor through a first pipeline, the compressor is connected to the unloading module through a second pipeline, the unloading module is connected to the storage tank through a third pipeline, the gasification pressure regulating device is connected to the storage tank through a fourth pipeline, the pressure reducing valve group is connected to the gasification pressure regulating device, and the combustion chamber is connected to the pressure reducing valve group;

[0073] (2) introducing high temperature gas into the reaction chamber and delivering uranyl nitrate solution into the reaction chamber, so that the uranyl nitrate solution and the high temperature gas come into contact with each other and undergo a thermal decomposition reaction to generate uranium trioxide and nitrogen oxides, thereby obtaining a powder mixed gas;

[0074] (3) The powder and gas in the reaction chamber are transported to the powder receiving hopper through the L discharge valve. After being filtered by the filter device, the gas is introduced into the tail gas purification system to recover nitric acid, so that the nitrogen oxides in the tail gas are converted into nitrogen gas before being discharged. After sedimentation, the powder is led out to the collection device to obtain a finished uranium trioxide product. The tail gas purification system specifically includes an absorption tower, an ammonia spraying device, a catalyst bed, a booster fan, a tail gas detection device and a chimney. The absorption tower is connected to the filter device, the ammonia spraying device is connected to the absorption tower, the catalyst bed is connected to the ammonia spraying device, the booster fan is connected to the catalyst bed, and the tail gas detection device and the chimney are respectively connected to the booster fan

[0075] Accordingly, the present invention also provides a high-activity uranium trioxide production device for processing large-flux uranyl nitrate, comprising a feeding system, a reaction system, a gas supply system, and a tail gas purification system, wherein:

[0076] The feeding system is connected to the reaction system and is used to deliver the uranyl nitrate solution to the reaction system;

[0077] The gas supply system is connected to the reaction system and is used to introduce gas into the reaction system. It specifically includes a storage tank, a compressor, an unloading module, a gasification pressure regulating device and a pressure reducing valve group. The storage tank is connected to the compressor through a first pipeline, the compressor is connected to the unloading module through a second pipeline, the unloading module is also connected to the storage tank through a third pipeline, the gasification pressure regulating device is connected to the storage tank through a fourth pipeline, and the pressure reducing valve group is connected to the gasification pressure regulating device;

[0078] The reaction system is used to receive fuel gas and uranyl nitrate solution and to generate high-temperature gas by combustion reaction of the fuel gas, so that the uranyl nitrate solution and the high-temperature gas are contacted to perform thermal decomposition reaction to generate uranium trioxide and nitrogen oxides. The reaction system specifically comprises a combustion chamber, a reaction chamber, a powder receiving hopper, a filtering device and a collecting device. The combustion chamber is connected to the pressure reducing valve group in the gas supply system, the reaction chamber is connected to the combustion chamber and the feeding system respectively, the reaction chamber is provided with an L discharge valve, the powder receiving hopper is connected to the reaction chamber through the L discharge valve, and the filtering device and the collecting device are connected to the powder receiving hopper respectively;

[0079] The exhaust gas purification system is connected to the reaction system and is used for deeply purifying the exhaust gas discharged from the reaction system. It specifically includes an absorption tower, an ammonia spraying device, a catalyst bed, a booster fan, an exhaust gas detection device and a chimney. The absorption tower is connected to the filtering device in the reaction system, the ammonia spraying device is connected to the absorption tower, the catalyst bed is connected to the ammonia spraying device, the booster fan is connected to the catalyst bed, and the exhaust gas detection device and the chimney are respectively connected to the booster fan.

[0080] Example 1

[0081] like Figure 1-4 As shown, this embodiment discloses a method for producing high-activity uranium trioxide by treating a large flux of uranyl nitrate, comprising:

[0082] Step (1) introduces fuel gas into the combustion chamber 3 in the reaction system through the gas supply system 4, so that the fuel gas undergoes a combustion reaction to generate high-temperature gas.

[0083] Among them, the gas supply system 4 includes a storage tank 03, a compressor 02, an unloading module 01, a gasification pressure regulating device and a pressure reducing valve group. The storage tank 03 is connected to the compressor 02 through a first pipeline, the compressor 02 is connected to the unloading module 01 through a second pipeline, the unloading module 01 is also connected to the storage tank 03 through a third pipeline 04, the gasification pressure regulating device is connected to the storage tank 03 through a fourth pipeline, the pressure reducing valve group is connected to the gasification pressure regulating device, and the combustion chamber 3 is connected to the pressure reducing valve group through an output terminal.

[0084] The unloading module 01 compresses and boosts the liquid fuel gas raw materials or gas fuel gas raw materials in the gas supply station through the compressor 02 to form a pressure difference with the storage tank 03, so that the fuel gas raw materials automatically flow into the storage tank 03 through the third pipeline 04, and then pass from the storage tank 03 to the gasification pressure regulating device, and then are reduced to a preset pressure through the pressure reducing valve group and transported to the combustion chamber 5 for combustion reaction.

[0085] In some embodiments, the fuel gas is liquefied petroleum gas (LPG), and the technical requirements for the use of the unloading module 01 are as follows:

[0086] a. Temperature: The temperature near the liquefied petroleum gas unloading is centrally displayed to ensure that the surrounding air temperature does not fluctuate too much during the unloading process.

[0087] b. Pressure: In the unloading module 01, the liquid / gas phase pressure of the unloading pipe is controlled at 0.60MPa, and the on-site pressure of the nitrogen pipe needs to be controlled below 0.5MPa.

[0088] c. Combustible gas detection: In the unloading module 01, when the combustible gas concentration reaches 25% LEL (lower explosion limit), an alarm is triggered and a buzzer sounds.

[0089] d. Fire monitoring signal: When a fire signal is detected in the unloading area, an alarm will be issued in time and the buzzer will sound.

[0090] In some embodiments, Figure 2 As shown, the gas supply system may further include a second unloading module 09, which is arranged in parallel with the unloading module 01, one for backup and the other for use.

[0091] In some embodiments, the gas supply system 4 further includes a release module 08 , which is connected to the storage tank 03 via a fifth pipeline and is used to release the fuel gas raw material from the storage tank 03 to the outside.

[0092] In some embodiments, the control amount of the release module 08 includes:

[0093] a. Temperature: In the emission module, a temperature-controlled vaporizer is set.

[0094] Among them, it is necessary to monitor the temperature next to the vaporizer and the temperature of the liquefied petroleum gas at the vaporizer outlet in real time. The temperature of the liquefied petroleum gas at the vaporizer outlet should be controlled at around 10°C. An alarm will be given if the temperature changes. If it is below 5°C, heating will be carried out. If it is below 3°C, an alarm will be triggered to shut down the vaporizer liquid inlet pipe control valve to prevent the liquefied petroleum gas from flowing into the vaporizer.

[0095] b. Pressure: The gasifier outlet pressure is controlled at 0.55MPa.

[0096] c. The combustible gas concentration and flame monitoring signals are consistent with the standards of the unloading module, that is: when the combustible gas concentration reaches 25%LEL, an alarm is triggered and a buzzer sounds; when a fire signal is detected, an alarm is triggered in time and a buzzer sounds.

[0097] Compared with the prior art, the gas supply system 4 of the present method can provide fuel gas raw materials for the production of high-flux uranyl nitrate, ensure the heat required for processing high-flux uranyl nitrate to produce high-activity uranium trioxide, ensure the complete reaction of the raw materials, thereby improving production efficiency and realizing large-scale production.

[0098] Step (2) introduces high temperature gas into the reaction chamber, and delivers uranyl nitrate solution to the reaction chamber, so that the uranyl nitrate solution and the high temperature gas are contacted and then thermally decomposed to generate uranium trioxide and nitrogen oxides, thereby obtaining a powder mixed gas. At the same time, the thermal decomposition reaction also generates oxygen, which can react with subsequent fuel gas to cause a combustion reaction, thereby promoting the denitration reaction of uranyl nitrate to proceed continuously.

[0099] Among them, the reactions carried out in the reaction chamber are mainly:

[0100] UO 2 (NO 3 ) 2 →UO 3 +NO x +O 2

[0101] C 3 H 8 +O 2 →CO 2 +H 2 O

[0102] In some embodiments, the temperature in the combustion chamber is 800-1400°C. Within this temperature range of the combustion chamber, the fuel gas can be fully burned, releasing a large amount of heat in a short period of time. When it enters the reaction chamber, the reaction chamber can be quickly heated up, greatly improving the reaction process in the reaction chamber without causing excessive combustion.

[0103] In some embodiments, the reaction temperature in the reaction chamber is controlled to be 440-500°C, and the pressure in the reaction chamber is controlled to be -5 kPa. When the uranyl nitrate material liquid contacts the high-temperature gas, a pyrolysis reaction occurs in the reaction chamber mainly under specific temperature conditions, which can improve the reaction efficiency, shorten the reaction time, make the reaction more complete, and obtain a large specific surface area of ​​the uranium trioxide powder particles, and greatly improve the activity.

[0104] In some embodiments, the feed concentration of the uranyl nitrate solution is 1000-2000 g / L, the feed flow rate is 200-400 L / h, and the concentration of nitric acid in the uranyl nitrate solution is 3-5 mol / L.

[0105] After a large number of experiments, the inventors found that under the feed concentration and flow conditions of the present method, the reaction can be timely and fully achieved to the greatest extent, avoiding the problem of insufficient reaction caused by excessive feed, and ensuring the steady increase of production scale. Too low feed concentration and feed flow rate make it difficult to achieve the expansion of the processing scale, and at the same time, it will easily cause the product activity to decrease to varying degrees; while too high feed concentration and feed flow rate will make the entire reaction system overloaded, unable to fully and completely react within the specified time, resulting in incomplete reaction. Subsequently, with the continuous excessively high feed concentration, a series of negative feedback will be triggered, which will cause a significant decrease in product activity, and the nitrogen oxide content in the subsequent exhaust gas will also be too high.

[0106] In some embodiments, the uranyl nitrate solution is sprayed into the reaction chamber by atomization nozzle, but it is not limited thereto and can also be directly introduced into the reaction chamber.

[0107] Furthermore, in order to ensure the realization of high-throughput uranyl nitrate to prepare highly active uranium trioxide, in some embodiments, the aperture of the atomizing nozzle is 0.2-1.2 mm, and the atomizing angle is 40-65°, so as to improve the atomization efficiency, increase the contact area of ​​the reactants, ensure the atomization effect of the high-throughput uranyl nitrate solution, accelerate the reaction rate, make the reaction more complete, avoid incomplete reaction due to poor atomization effect, high water content of the product, and ensure product quality. If an atomizing nozzle with other parameters is used, the reaction will be affected to varying degrees due to excessive or insufficient spray, which will have a significant inhibitory effect on the improvement of the reaction efficiency, which is not conducive to the stable and efficient production of the entire process system.

[0108] In this embodiment, the aperture of the atomizing nozzle is 0.8 mm, and the atomizing angle is 45°. Experiments have found that under the optimal atomizing nozzle parameter conditions, the raw material liquid of the uranyl nitrate solution can be atomized into droplets with very small particle sizes. On the one hand, the surface area of ​​the uranyl nitrate solution can be greatly increased. The atomized uranyl nitrate solution has a small volume and a large surface area, and is easier to contact with other substances (such as high-temperature gas), thereby improving the reaction efficiency; on the other hand, after atomization, the viscosity of the uranyl nitrate solution is reduced, and the fluidity is enhanced, making it easier to mix and disperse. At the same time, the uniformity of the uranyl nitrate solution is improved, making it more stable during the reaction process, thereby improving the quality of the product.

[0109] Step (3) The powder mixed gas in the reaction chamber 2 is transported to the powder receiving hopper 8 through the L discharge valve 10. After being filtered by the filter device 7, the gas is introduced into the tail gas purification system 6 to recover nitric acid, and then the nitrogen oxides in the tail gas are converted into nitrogen gas before being discharged. After sedimentation, the powder is led out to the collection device to obtain a finished uranium trioxide product.

[0110] Among them, the L unloading valve 10 includes a vertical pipe and a horizontal pipe, the vertical pipe is connected to the reaction chamber 2, one end of the horizontal pipe is connected to the vertical pipe, and the other end is connected to the powder receiving bucket 8; the exhaust gas purification system 6 specifically includes an absorption tower, an ammonia spraying device 210, a catalyst bed 211, a booster fan 21, an exhaust gas detection device 212 and a chimney 213, the absorption tower is connected to the filtering device 7, the ammonia spraying device 210 is connected to the absorption tower, the catalyst bed 211 is connected to the ammonia spraying device 210, the booster fan 21 is connected to the catalyst bed 211, the exhaust gas detection device 212 and the chimney 213 are respectively connected to the booster fan 21, and control valves 22 are respectively provided on the connecting pipes between the devices.

[0111] The powder mixed gas in the reaction chamber 2 enters the L discharge valve 10. When the drag force generated by the gas flowing in the L discharge valve 10 exceeds the flow resistance of the powder particles in the powder mixed gas in the L discharge valve 10, the entire powder mixed gas can move in the entire L discharge valve 10, thereby further continuing the reaction in the reaction chamber, that is, continuing the thermal decomposition reaction, thereby improving the reaction efficiency and reaction degree, and making the reaction complete.

[0112] After the powder mixed gas enters the powder receiving bucket 8, it is filtered by the filtering device 7, and the powder is trapped in the powder receiving bucket 8. After sedimentation, it is led out to obtain the finished uranium trioxide product. The filtered gas is introduced into the bottom of the absorption tower in the tail gas treatment system 6. The gas enters the packing layer after being distributed by the gas distributor, and the absorbent is introduced from the top of the absorption tower to make the gas and the absorbent contact in countercurrent in the absorption tower. The nitrogen oxides in the gas transfer mass and heat with the absorbent on the surface of the packing, and react to obtain the recovered nitric acid.

[0113] The tail gas after the reaction in the absorption tower has a greatly reduced nitrogen oxide content. The tail gas is introduced into the ammonia injection device 210, mixed with ammonia, and then introduced into the catalyst bed 211 for catalytic reaction to convert it into nitrogen. The reaction formula is NOx+NH 3 →N 2 +H 2 O, after being detected by the exhaust gas detection device 212 to meet the exhaust gas emission standards, is transported to the chimney 213 through the booster fan 21 for discharge.

[0114] Compared with the prior art, the tail gas purification system 6 of the present method adopts wet absorption coupled with dry denitration technology. Through the absorption tower, the ammonia injection device 210 and the catalyst bed 211 are used to greatly improve the purification effect of nitrogen oxides, and achieve deep purification of ultra-high concentration nitrogen oxides produced by high-throughput uranyl nitrate thermal decomposition. While recovering nitric acid, deep purification of nitrogen oxides is achieved. NO in the treated tail gas x The content is less than 240mg / Nm3, and NH 3 The escape amount can be controlled below 3ppm, meeting the exhaust emission standards.

[0115] In some embodiments, the inner diameter of the L discharge valve 10 is 10-100 mm, the length of the horizontal pipe is 300-400 mm, the temperature inside the L discharge valve 10 is controlled to be 300-500° C., and the inflation rate is controlled to be 0.1-5 m 3 / h.

[0116] Experiments have found that by setting the inflation rate of the present method, the flow area of ​​the powder in the vertical tube and the horizontal tube of the L discharge valve 10 can be expanded. Under this higher inflation amount, all the tube sections of the L discharge valve are in an active state, which can further enhance the collision and contact reactions between the components, thereby further improving the reaction efficiency, completing the reaction, and promoting the molding of uranium trioxide powder.

[0117] In this embodiment, the inner diameter of the L discharge valve 10 is 27 mm, the length of the horizontal pipe is 317 mm, the temperature inside the L discharge valve 10 is controlled to 465° C., and the inflation rate is controlled to 0.6 m 3 / h.

[0118] In some embodiments, the filter device 7 uses a high-performance filter composite membrane as a filter element, and the high-performance filter composite membrane is made in the following manner:

[0119] preparing a composite spinning solution;

[0120] Ultrasonic treatment is performed on the composite spinning solution to obtain a pretreated composite spinning solution;

[0121] The spinning solution is subjected to electrostatic spinning to obtain a composite spinning membrane;

[0122] The composite spinning membrane is dried at 80° C. for 20 hours to obtain the high-performance filtration composite membrane.

[0123] The existing filter materials (glass fiber filter membrane, sprayed fleece, etc.) have relatively thick fiber diameters, which are not suitable for filtering tiny UO 3 The filtration effect of powder particles is not ideal, and there will be more UO 3 The powder particles follow the filtered gas through the filter material, and the existing filter material has large filtration resistance and high energy consumption. Compared with the prior art, this method uses the high-performance filter composite membrane as the filter element of the filter device 7, which has the characteristics of a nanofiber membrane, high purity, good uniformity, large specific surface area, and high comprehensive performance, and can more effectively intercept tiny UO in the filtered gas. 3 Powder particles, and maintain relatively low filtration resistance, high filtration efficiency, can greatly avoid UO 3 The discharge of powder particles is wasteful.

[0124] In some embodiments, the voltage of electrospinning is 16-18 kV, the receiving distance is fixed at 18 cm, the ambient temperature of the spinning room is 25°C, and the humidity is 35%. In this way, very fine ultrafine fibers can be prepared. The surface area of ​​these ultrafine fibers is very large, which can improve the adsorption performance of the prepared high-performance filtration composite membrane. At the same time, by performing electrospinning at a voltage of 16-18 kV, the prepared high-performance filtration composite membrane has higher purity and better uniformity, which can further improve the overall performance.

[0125] In some embodiments, the thickness of the high performance filtration composite membrane is 20-100 μm, and in this embodiment, it is preferably controlled to be 35 μm.

[0126] In some embodiments, the composite spinning solution is prepared by:

[0127] Adding polystyrene resin to an organic solvent, stirring and mixing evenly, then adding nanocomposite material and N, N', N"-tris[1-(methoxymethyl)propyl]benzene-1,3,5-tricarboxamide respectively, adjusting the temperature to 70°C, keeping the temperature and stirring for 30 minutes, and then performing ultrasonic dispersion for 5 minutes to obtain the composite spinning solution;

[0128] Wherein, the organic solvent is DMF (i.e., N,N-dimethylformamide solvent);

[0129] The mass ratio of polystyrene resin and DMF is 12-15:100;

[0130] The mixing mass ratio of polystyrene resin, nano composite material and N, N', N"-tris[1-(methoxymethyl)propyl]benzene-1,3,5-tricarboxamide is 40:1-3:4-5.

[0131] In some embodiments, the nanocomposite is prepared by:

[0132] The nano-bentonite was added into ethanol and dispersed by ultrasonic for 10 min to obtain a dispersion;

[0133] Adding coal slag powder and lignin into the dispersion, stirring for 30 minutes, and drying to obtain a mixture;

[0134] The mixed material is added into a tubular furnace, heated and calcined for 3 hours under the protection of an inert atmosphere, and then naturally cooled to room temperature to obtain the nanocomposite material;

[0135] Wherein, the mixing mass ratio of the nano-bentonite and ethanol is 1:5-6;

[0136] The mass ratio of the nano-bentonite, coal slag powder and lignin is 10:1-2:3-5;

[0137] The inert atmosphere is nitrogen;

[0138] The heating calcination temperature is 820-860°C.

[0139] In some embodiments, the absorption tower uses multiple absorption towers connected in series, and each absorption tower is equipped with Y-250 type 304 stainless steel structured packing. The treatment is carried out through multi-stage absorption towers, and the treatment efficiency is higher and the treatment effect is better.

[0140] In this embodiment, Figure 3 As shown, four absorption towers are used, namely, the first absorption tower 24, the second absorption tower 25, the third absorption tower 26 and the fourth absorption tower 27. The first absorption tower 24, the second absorption tower 25, the third absorption tower 26 and the fourth absorption tower 27 are arranged in series in sequence. The first absorption tower 24 is connected to the filter device 7 in the reaction system, and the fourth absorption tower 27 is connected to the ammonia spraying device 210. The first absorption tower 24, the second absorption tower 25, the third absorption tower 26 and the fourth absorption tower 27 are all provided with Y-250 type 304 stainless steel structured packing, and the connecting pipes between the various devices are respectively provided with control valves 22. After the gas filtered by the filter device 7 enters the first-stage absorption tower 24, it is dispersed by the gas distributor at the bottom and then enters the packing layer, and is countercurrently contacted with the absorbent sprayed from the top of the first absorption tower 24. The nitrogen oxides and the absorbent are subjected to mass transfer and heat transfer on the surface of the packing. After the nitrogen oxides are absorbed, they enter the absorbent to form nitric acid.

[0141] In some embodiments, the absorbent is water, and the reaction occurring in the absorption tower is mainly:

[0142] NOx+H 2 O→HNO 3.

[0143] In some embodiments, the catalyst bed is V 2 O 5 / TiO 2 Catalytic denitrification catalyst. After the gas treated by the absorption tower enters the catalyst bed, the nitrogen oxides and ammonia in it are catalyzed by the catalyst to form nitrogen. The reaction formula is:

[0144] NOx+NH 3 →N 2 +H 2 O

[0145] In some embodiments, the method further comprises:

[0146] Before the gas filtered by the filter device enters the absorption tower, the gas filtered by the filter device is first condensed, the condensed non-condensable gas is heat exchanged with the gas after the catalyst bed reaction, and then the non-condensable gas after the heat exchange is passed into the absorption tower to form nitric acid;

[0147] Before the gas treated in the absorption tower enters the catalyst bed, the tail gas after the nitric acid is recovered in the absorption tower is first heated, and then introduced into the ammonia injection device to mix with ammonia and then introduced into the catalyst bed for catalytic reaction to form nitrogen.

[0148] That is to say, the exhaust gas purification system 6 also includes a condenser 215, a heat exchanger 23 and a heating furnace 28, wherein: the absorption tower is connected to the first channel outlet end of the heat exchanger 23, the first channel inlet end of the heat exchanger 23 is connected to the condenser 215, and the condenser 215 is further connected to the filtering device 7 in the reaction system, that is, the absorption tower is connected to the filtering device 7 through the heat exchanger 23 and the condenser 215; the ammonia injection device 210 is connected to the heating furnace 28, and the heating furnace 28 is further connected to the absorption tower, that is, the ammonia injection device 210 is connected to the absorption tower through the heating furnace 28; and control valves 22 are respectively provided on the connecting pipes between the various devices.

[0149] In some embodiments, fuel gas is introduced into the heating furnace 28 through the feeding system 1 , and heating is performed by combustion of the fuel gas in the heating furnace 28 , that is, the pressure reducing valve group in the feeding system 1 is also connected to the heating furnace 28 .

[0150] Step (4) After the production is completed, the supply of gas is stopped, the combustion chamber 3 is cooled by the cooling system 5, and the remaining residues are collected and cleaned, dried, and then collected again to complete the entire production process.

[0151] The high-activity uranium trioxide production method for processing large-flux uranyl nitrate in this embodiment is mainly used in uranium purification process and post-processing process. Compared with the prior art, by optimizing the full-process layout of the gas supply system-reaction system and tail gas purification system, the obtained uranium trioxide product has a large specific surface area and high activity, and has a large processing flux, high tail gas treatment efficiency and good effect. It can achieve a processing capacity of more than 5 tons of uranium / day, can be adapted to future thousand-ton nuclear chemical plants and further improve uranium conversion capacity, solve the problems that the prior art cannot process high-flux uranyl nitrate and serious excess of nitrogen oxides, and is the first time that a full-process flame denitrification process for the nuclear fuel cycle system has been proposed, which is of great significance to the sustainable development of nuclear energy. Specifically:

[0152] 1. By optimizing the gas supply system, the circuit is simple, the operation is convenient, the safety is high, and it can provide stable energy raw materials. In addition, it can also provide gas for the reaction system and the tail gas purification system at the same time, so that each reaction process can be carried out continuously and the processing efficiency is improved;

[0153] 2. By optimizing the reaction conditions of the gas supply system and the reaction system, it is possible to make real-time adjustments according to the heat required for the thermal reaction to maximize the reaction efficiency, thereby providing a guarantee for the high-throughput uranium conversion capacity of the entire production system. Multiple solutions are being developed simultaneously to jointly improve the processing throughput and achieve a processing capacity of more than 5 tons of uranium per day, thereby increasing the production scale, which is not possible with existing technologies;

[0154] 3. By setting the L discharge valve, the reaction in the reaction chamber can be continued, the utilization rate of the heat released by the combustion of the gas can be improved, the reaction efficiency and reaction degree can be improved, and the reaction can be completed. Compared with the prior art using a disc valve for discharge, it can avoid the problem that the incomplete reaction of some uranyl nitrates due to the limited contact time between the high-temperature gas and the reaction raw materials (especially after the processing flux is increased, this problem will be more significant), resulting in a significant reduction in product quality, etc.;

[0155] 4. By optimizing the filtering device, the interception capacity of uranium trioxide particles carried in the tail gas can be improved, so as to adapt to the problem of more uranium trioxide particles and powder in the tail gas caused by increasing the production scale, and prevent UO 3 The powder is discharged along with the gas, resulting in a waste of resources, making the radioactivity level of the waste liquid generated by the entire system lower than 50μgU / L, which meets the domestic emission standards;

[0156] 5. By optimizing the tail gas purification system and adopting wet absorption coupled with dry denitration technology, the purification effect of nitrogen oxides can be greatly improved and ammonia escape can be controlled, thereby adapting to the problem of more nitrogen oxide waste gas generated after high-throughput treatment, and realizing the deep purification of ultra-high concentration nitrogen oxides produced by high-throughput uranyl nitrate thermal decomposition, which can not only recover nitric acid but also meet the tail gas emission standards;

[0157] 6. By using cheap liquefied petroleum gas as fuel, costs can be reduced. At the same time, by controlling the combustion of fuel gas and oxygen in the combustion chamber, process energy consumption can also be reduced;

[0158] 7. By optimizing the atomizing nozzle and using the spray method to allow the uranyl nitrate solution to enter the reaction chamber, higher reaction efficiency can be achieved and UO 3 The specific surface area of ​​the product particles maintains a higher reactivity, thereby greatly broadening the application range of the product.

[0159] Example 2

[0160] like Figure 1-4 As shown, this embodiment discloses a high-activity uranium trioxide production device for processing large-flux uranyl nitrate, which is used in the method described in Example 1, including a feeding system 1, a reaction system, a gas supply system 4, and a tail gas purification system 6, wherein:

[0161] The feeding system 1 is connected to the reaction system and is used to deliver uranyl nitrate solution to the reaction system;

[0162] The gas supply system 4 is connected to the reaction system and is used to introduce fuel gas into the reaction system. It specifically includes a storage tank 03, a compressor 02, an unloading module 01, a gasification pressure regulating device and a pressure reducing valve group. The storage tank 03 is connected to the compressor 02 through a first pipeline, the compressor 02 is connected to the unloading module 01 through a second pipeline, the unloading module 01 is also connected to the storage tank 03 through a third pipeline 04, the gasification pressure regulating device is connected to the storage tank 03 through a fourth pipeline, and the pressure reducing valve group is connected to the gasification pressure regulating device;

[0163] The reaction system is used to receive fuel gas and uranyl nitrate solution and to generate high-temperature gas by combustion reaction of fuel gas, so that uranyl nitrate solution and high-temperature gas are contacted and then thermally decomposed to generate uranium trioxide and nitrogen oxides. The reaction system specifically includes a combustion chamber 3, a reaction chamber 2, a powder receiving hopper 8, a filtering device 7 and a collecting device 9. The combustion chamber 3 is connected to the pressure reducing valve group in the gas supply system 4, the reaction chamber 2 is connected to the combustion chamber 3 and the feeding system 1 respectively, the reaction chamber 2 is provided with an L discharge valve 10, the powder receiving hopper 8 is connected to the reaction chamber 2 through the L discharge valve 10, and the filtering device 7 and the collecting device 9 are connected to the powder receiving hopper 8 respectively;

[0164] The exhaust gas purification system 6 is connected to the reaction system and is used to perform deep purification on the exhaust gas discharged from the reaction system. It specifically includes an absorption tower, an ammonia spraying device 210, a catalyst bed 211, a booster fan 21, an exhaust gas detection device 212 and a chimney 213. The absorption tower is connected to the filtering device 7 in the reaction system, the ammonia spraying device 210 is connected to the absorption tower, the catalyst bed 211 is connected to the ammonia spraying device 210, the booster fan 21 is connected to the catalyst bed 211, and the exhaust gas detection device 212 and the chimney 213 are respectively connected to the booster fan 21

[0165] Specifically, the unloading module 01 compresses and boosts the pressure of the liquid fuel gas raw materials or gas fuel gas raw materials in the gas supply station through the compressor 02 to form a pressure difference with the storage tank, so that the fuel gas raw materials automatically flow into the storage tank 03 through the third pipeline 04, and then pass from the storage tank 03 to the gasification pressure regulating device, and then are reduced to a preset pressure through the pressure reducing valve group and transported to the combustion chamber 3 for combustion reaction.

[0166] In some embodiments, the fuel gas is liquefied petroleum gas (LPG), and the technical requirements for the use of the unloading module 01 are as follows:

[0167] a. Temperature: The temperature near the liquefied petroleum gas unloading is centrally displayed to ensure that the surrounding air temperature does not fluctuate too much during the unloading process.

[0168] b. Pressure: In the unloading module 01, the liquid / gas phase pressure of the unloading pipe is controlled at 0.60MPa, and the on-site pressure of the nitrogen pipe needs to be controlled below 0.5MPa.

[0169] c. Combustible gas detection: In the unloading module 01, if the combustible gas concentration reaches 25% LEL, an alarm will be triggered and a buzzer will sound.

[0170] d. Fire monitoring signal: When a fire signal is detected in the unloading area, an alarm will be issued in time and the buzzer will sound.

[0171] In some embodiments, the gas supply system also includes a release module 08, which is connected to the storage tank 03 through a fifth pipeline and is used to release the liquid fuel gas raw material from the storage tank 03 to the outside. In addition, a temperature-controlled gasifier is provided in the release module 08, which can detect the temperature and pressure around the gasifier and perform interlocking control.

[0172] Specifically, the control quantities of the release module 08 include:

[0173] a. Temperature: Real-time monitoring of the temperature beside the vaporizer and the temperature of the liquefied petroleum gas at the vaporizer outlet is carried out. The temperature of the liquefied petroleum gas at the vaporizer outlet is controlled at or around 10°C. An alarm is triggered when the temperature changes. If the temperature is lower than 5°C, heating is carried out. If the temperature is lower than 3°C, an alarm is triggered to shut down the vaporizer liquid inlet pipe control valve, so that the liquefied petroleum gas no longer flows into the vaporizer.

[0174] b. Pressure: The gasifier outlet pressure is controlled at 0.55MPa.

[0175] c. The combustible gas concentration and flame monitoring signals are consistent with the standards of the unloading module 08, that is, when the combustible gas concentration reaches 25%LEL, an alarm is triggered and a buzzer sounds; when a fire signal is detected, an alarm is triggered in time and a buzzer sounds.

[0176] Compared with the existing technology, the gas supply system of this equipment can provide fuel gas raw materials for the production of high-throughput uranyl nitrate, ensure the heat required for processing high-throughput uranium nitrate to produce high-activity uranium trioxide, ensure the complete reaction of the raw materials, thereby improving production efficiency and realizing large-scale production.

[0177] In some embodiments, an atomizing nozzle is provided at the tail end of the feeding system 1 so that the delivered uranyl nitrate solution enters the reaction chamber 2 in a spray manner.

[0178] Furthermore, in order to ensure the realization of high-throughput uranyl nitrate for the preparation of highly active uranium trioxide, in some embodiments, the aperture of the atomizing nozzle is 0.2-1.2 mm, and the atomizing angle is 40-65°, so as to improve the atomization efficiency, increase the contact area of ​​the reactants, ensure the atomization effect of the high-throughput uranyl nitrate solution, accelerate the reaction rate, make the reaction more complete, avoid incomplete reaction due to poor atomization effect, and ensure the product quality with high water content.

[0179] In this embodiment, the aperture of the atomizing nozzle is 0.8 mm, and the atomizing angle is 45°. Experiments have found that under the optimal atomizing nozzle parameter conditions, the raw material liquid of the uranyl nitrate solution can be atomized into droplets with very small particle sizes. On the one hand, the surface area of ​​the uranyl nitrate solution can be greatly increased. The atomized uranyl nitrate solution has a small volume and a large surface area, and is easier to contact with other substances (such as high-temperature gas), thereby improving the reaction efficiency; on the other hand, after atomization, the viscosity of the uranyl nitrate solution is reduced, and the fluidity is enhanced, making it easier to mix and disperse. At the same time, the uniformity of the uranyl nitrate solution is improved, making it more stable during the reaction process, thereby improving the quality of the product.

[0180] Specifically, the L discharge valve 10 includes a vertical tube and a horizontal tube. The vertical tube is connected to the reaction chamber 2 . One end of the horizontal tube is connected to the vertical tube, and the other end is connected to the powder receiving hopper 8 .

[0181] In some embodiments, the inner diameter of the L discharge valve 10 is 10-100 mm, the length of the horizontal pipe is 300-400 mm, the temperature inside the L discharge valve is controlled to be 300-500° C., and the inflation rate is controlled to be 0.1-5 m 3 / h.

[0182] By setting a suitable inflation rate, the flow area of ​​the powder in the vertical and horizontal tubes of the L discharge valve can be expanded. Under this higher inflation amount, all the tube sections of the L discharge valve are in an active state, which can further enhance the collision and contact reactions between the components, thereby further improving the reaction efficiency, completing the reaction, and promoting the molding of uranium trioxide powder.

[0183] In this embodiment, the inner diameter of the L discharge valve 10 is 27 mm, the length of the horizontal pipe is 317 mm, the temperature inside the L discharge valve is controlled to 465° C., and the inflation rate is controlled to 0.6 m 3 / h.

[0184] In some embodiments, the filter device 7 uses a high-performance filter composite membrane as a filter element, and the specific surface area of ​​the high-performance filter composite membrane is 8-20m 2 / g, the thickness of the high performance filtration composite membrane is 20-100 μm, preferably 35 μm.

[0185] Specifically, the high-performance filtration composite membrane is prepared in the following manner:

[0186] preparing a composite spinning solution;

[0187] Ultrasonic treatment is performed on the composite spinning solution to obtain a pretreated composite spinning solution;

[0188] The spinning solution is subjected to electrostatic spinning to obtain a composite spinning membrane;

[0189] The composite spinning membrane is dried at 80° C. for 20 hours to obtain the high-performance filtration composite membrane.

[0190] Compared with the prior art, by using the high-performance filtration composite membrane as the filter element of the filtration device, the purity is high, the uniformity is good, the specific surface area is large, and the comprehensive performance is high, and the tiny UO in the filtered gas can be more effectively intercepted. 3 Powder particles.

[0191] More specifically, the voltage of electrospinning is 16-18kV, the receiving distance is fixed at 18cm, the ambient temperature of the spinning room is 25°C, and the humidity is 35%. In this way, very fine ultrafine fibers can be prepared. The surface area of ​​these ultrafine fibers is very large, which can improve the adsorption performance of the prepared high-performance filtration composite membrane. At the same time, by electrospinning at a voltage of 16-18kV, the prepared high-performance filtration composite membrane has higher purity and better uniformity, which can further improve the overall performance.

[0192] More specifically, the composite spinning solution is prepared in the following manner:

[0193] Adding polystyrene resin to an organic solvent, stirring and mixing evenly, then adding nanocomposite material and N, N', N"-tris[1-(methoxymethyl)propyl]benzene-1,3,5-tricarboxamide respectively, adjusting the temperature to 70°C, keeping the temperature and stirring for 30 minutes, and then performing ultrasonic dispersion for 5 minutes to obtain the composite spinning solution;

[0194] Wherein, the organic solvent is DMF;

[0195] The mass ratio of polystyrene resin and DMF is 12-15:100;

[0196] The mixing mass ratio of polystyrene resin, nano composite material and N, N', N"-tris[1-(methoxymethyl)propyl]benzene-1,3,5-tricarboxamide is 40:1-3:4-5.

[0197] More specifically, the nanocomposite is prepared in the following manner:

[0198] The nano-bentonite was added into ethanol and dispersed by ultrasonic for 10 min to obtain a dispersion;

[0199] Adding coal slag powder and lignin into the dispersion, stirring for 30 minutes, and drying to obtain a mixture;

[0200] The mixed material is added into a tubular furnace, heated and calcined for 3 hours under the protection of an inert atmosphere, and then naturally cooled to room temperature to obtain the nanocomposite material;

[0201] Wherein, the mixing mass ratio of the nano-bentonite and ethanol is 1:5-6;

[0202] The mass ratio of the nano-bentonite, coal slag powder and lignin is 10:1-2:3-5;

[0203] The inert atmosphere is nitrogen;

[0204] The heating calcination temperature is 820-860°C.

[0205] In some embodiments, the absorption tower uses multiple absorption towers connected in series in sequence, and the treatment is performed through multi-stage absorption towers, which has higher treatment efficiency and better treatment effect.

[0206] In this embodiment, Figure 3 As shown, four absorption towers are used, that is, the absorption towers include a first absorption tower 24, a second absorption tower 25, a third absorption tower 26 and a fourth absorption tower 27. The first absorption tower 24, the second absorption tower 25, the third absorption tower 26 and the fourth absorption tower 27 are arranged in series in sequence. The first absorption tower 24 is connected to the filtering device 7 in the reaction system, and the fourth absorption tower 27 is connected to the ammonia injection device 210. The first absorption tower 24, the second absorption tower 25, the third absorption tower 26 and the fourth absorption tower 27 are all provided with Y-250 type 304 stainless steel structured packing and a gas distributor, and control valves 22 are respectively provided on the connecting pipes between the various devices.

[0207] In some embodiments, the absorbent in the absorption tower is water, and the reaction occurring in the absorption tower is mainly:

[0208] NOx+H 2 O→HNO 3 .

[0209] In some embodiments, the catalyst bed is V 2 O 5 / TiO 2 Catalytic denitrification catalyst.

[0210] In some embodiments, the exhaust gas purification system 6 further includes a condenser 215, a heat exchanger 23 and a heating furnace 28, wherein:

[0211] The absorption tower is connected to the first channel outlet end of the heat exchanger 23, and the first channel inlet end of the heat exchanger 23 is connected to the condenser 215, and the condenser 215 is further connected to the filter device 7 in the reaction system, that is, the absorption tower is connected to the filter device 7 through the heat exchanger 23 and the condenser 215;

[0212] The ammonia spraying device 210 is connected to the heating furnace 28, and the heating furnace 28 is further connected to the absorption tower, that is, the ammonia spraying device 210 is connected to the absorption tower through the heating furnace 28;

[0213] In addition, control valves 22 are respectively provided on the connecting pipelines between the various devices.

[0214] The gas filtered by the filter device 7 is first passed into the condenser 215 for condensation treatment to condense the water vapor contained in the gas; the condensed non-condensable gas is then passed into the heat exchanger 23 for heat exchange with the gas reacted with the catalyst bed 211 passed into the heat exchanger 23 to initially heat the non-condensable gas; the gas after the initial heating is passed into the absorption tower for reaction to recover nitric acid; the exhaust gas treated by the absorption tower is passed into the heating furnace 28 for heating, the exhaust gas is heated again, and then passed into the ammonia injection device 210, mixed with ammonia, and passed into the catalyst bed 211 for catalytic reaction, thereby converting the nitrogen oxides in the exhaust gas into nitrogen.

[0215] In some embodiments, the heating furnace 28 is connected to the pressure reducing valve group in the gas supply system 4 to allow the gas to flow in. That is, the gas supply system 4 can provide gas to the reaction system 1 and the tail gas purification system 6 at the same time.

[0216] Specifically, if Figure 3 As shown, at this time, the gasification pressure regulating device includes a first gasification pressure regulating device 051 and a second gasification pressure regulating device 0, and the pressure reducing valve group includes a first pressure reducing valve group 061 and a second pressure reducing valve group 06, wherein: the first gasification pressure regulating device 051 and the second gasification pressure regulating device 05 are respectively connected to the storage tank 03; the first pressure reducing valve group 061 is connected to the first gasification pressure regulating device 051, the second pressure reducing valve group 06 is connected to the second gasification pressure regulating device 05, the heating furnace 28 is connected to the second pressure reducing valve group 06 through the second output terminal 07, and the combustion chamber 3 is connected to the first pressure reducing valve group 061 through the first output terminal 071.

[0217] In some embodiments, the device further comprises a cooling system 5, which is connected to the combustion chamber 3 and is used to cool the combustion chamber.

[0218] After the production is finished, the gas supply is stopped, the combustion chamber is cooled by the cooling system, the remaining residues are collected and cleaned, dried and collected again, completing the entire production process.

[0219] Example 3

[0220] like Figure 1-4 As shown, this embodiment discloses a method for producing high-activity uranium trioxide by treating a large flux of uranyl nitrate, the steps comprising:

[0221] (1) Fuel gas is introduced into the combustion chamber 3 through the gas supply system 4, causing the fuel gas to undergo a combustion reaction and generate high-temperature gas.

[0222] Wherein, the gas supply system 4 includes a storage tank 03, which is connected to the compressor 02 through a first pipeline 04, and the compressor 02 is connected to the unloading module 01 through a second pipeline. The unloading module 01 is used to obtain liquid-phase gas raw materials or gas-phase gas raw materials from the gas supply station, and the storage tank 03 is connected to the dispersion module 08 through a fifth pipeline. The storage tank 03 is respectively connected to the first gasification pressure regulating device 051 and the second gasification pressure regulating device 05 through pipelines, and is respectively connected to the first output terminal 071 and the second output terminal 07 through the first pressure reducing valve group 061 and the second pressure reducing valve group 06. The liquefied petroleum gas is output to the combustion chamber 3 through the first output terminal 071 for gas combustion reaction to generate high-temperature gas, and the liquefied petroleum gas is transported to the heating furnace 28 in the exhaust gas purification system 6 through the second output terminal 07 for combustion and heating;

[0223] The temperature inside the combustion chamber is 800°C.

[0224] (2) High-temperature gas is introduced into the reaction chamber 2, and a uranyl nitrate solution is transported into the reaction chamber 2 through the feeding system 1, so that the uranyl nitrate solution and the high-temperature gas are contacted and thermally decomposed to generate uranium trioxide and nitrogen oxides, thereby obtaining a powder mixed gas.

[0225] The uranyl nitrate solution delivered by the feeding system 1 is sprayed into the reaction chamber 2 by an atomizing nozzle;

[0226] The aperture of the atomizing nozzle is 0.8mm and the atomizing angle is 45°;

[0227] The feed concentration of uranyl nitrate solution is 1000 g / L, the feed flow rate is 200 L / h, and the nitric acid concentration in the feed solution is 3 mol / L;

[0228] The reaction temperature of reaction chamber 2 is 480°C, and the pressure of reaction chamber 2 is -5Kpa.

[0229] (3) The powder mixed gas in the reaction chamber 2 is transported to the powder receiving hopper 8 through the L discharge valve 10. After being filtered by the filter device 7, the gas is introduced into the tail gas purification system 6 to recover nitric acid and convert nitrogen oxides in the tail gas into nitrogen before being discharged. After sedimentation, the powder is led out to the collection device to obtain a finished uranium trioxide product.

[0230] Among them, the inner diameter of the L discharge valve 10 is 27 mm, the horizontal pipe length of the L discharge valve 10 is 317 mm, the temperature inside the L discharge valve 10 is 465° C., and the inflation rate is 0.6 m3 / h;

[0231] The exhaust gas purification system 6 includes: an exhaust gas inlet 20, a heat exchanger 23, a first absorption tower 24, a second absorption tower 25, a third absorption tower 26, a fourth absorption tower 27, a heating furnace 28, an ammonia inlet 29, an ammonia injection device 210, a catalyst bed 211, a booster fan 21, an exhaust gas detection device 212, a chimney 213, a control valve 22, a pipeline, and a condenser 215; wherein the exhaust gas inlet 20 is connected to the condenser 215 through a pipeline, the condenser 215 is further connected to the heat exchanger 23 through a pipeline, the heat exchanger 23 is connected to the booster fan 21 through a pipeline, and the heat exchanger 23 is sequentially connected to the first absorption tower 24, the second absorption tower 25, the third absorption tower 26, the fourth absorption tower 27, the heating furnace 28, the ammonia inlet 29, the ammonia injection device 210, the catalyst bed 211, the booster fan 21, the exhaust gas detection device 212, the chimney 213, the control valve 22, a pipeline, and a condenser 215; wherein the exhaust gas inlet 20 is connected to the condenser 215 through a pipeline, the condenser 215 is further connected to the heat exchanger 23 through a pipeline, the heat exchanger 23 is connected to the booster fan 21 through a pipeline, and the heat exchanger 23 is sequentially connected to the first absorption tower 24, the second absorption tower 25, the third absorption tower 26, the fourth absorption tower 27, the heating furnace 28, the ammonia inlet 29, the ammonia injection device 210, the catalyst bed 211, the booster fan 21, the exhaust gas detection device 212, the chimney 21 The collecting tower 25, the third absorption tower 26, and the fourth absorption tower 27, the fourth absorption tower 27 is connected to the heating furnace 28 through a pipeline, the heating furnace 28 is connected to the ammonia injection device 210 through a pipeline, the ammonia injection device 210 is connected to the catalyst bed 211, the ammonia injection device passes ammonia gas to the catalyst bed 2111 through an ammonia inlet 29, the catalyst bed 211 is respectively connected to the heat exchanger 23 and the booster fan 21 through pipelines, an exhaust gas detection device 212 is provided between the booster fan 21 and the catalyst bed 211, and the booster fan 21 is connected to the chimney 213 through a pipeline, wherein the pipelines connecting the various devices are respectively provided with control valves 22;

[0232] The filter device 7 uses a high-performance filter composite membrane as a filter element. The preparation method of the high-performance filter composite membrane includes the following steps:

[0233] preparing a composite spinning solution;

[0234] Ultrasonic treatment is performed on the composite spinning solution to obtain a pretreated composite spinning solution;

[0235] The spinning solution is subjected to electrostatic spinning and then dried at 80° C. for 20 hours to obtain a high-performance filtration composite membrane having a thickness of 35 μm.

[0236] The preparation method of the composite spinning solution is as follows:

[0237] Add polystyrene resin to the organic solvent, stir and mix evenly, then add nanocomposite material and N, N', N"-tri[1-(methoxymethyl)propyl]benzene-1,3,5-tricarboxamide respectively, adjust the temperature to 70°C, keep stirring for 30 minutes, and then disperse by ultrasonic for 5 minutes to obtain a composite spinning solution;

[0238] Wherein, the organic solvent is DMF;

[0239] The mass ratio of polystyrene resin and DMF is 12:100;

[0240] The mixing mass ratio of polystyrene resin, nanocomposite material and N,N',N"-tri[1-(methoxymethyl)propyl]benzene-1,3,5-tricarboxamide is 40:1:4.

[0241] The preparation method of the nanocomposite material is as follows:

[0242] The nano-bentonite was added into ethanol and dispersed by ultrasonic for 10 min to obtain a dispersion;

[0243] Adding coal slag powder and lignin into the dispersion, stirring for 30 minutes, and drying to obtain a mixture;

[0244] The mixed material is added into a tubular furnace, heated and calcined for 3 hours under the protection of an inert atmosphere, and then naturally cooled to room temperature to obtain a nanocomposite material;

[0245] Wherein, the mixing mass ratio of the nano-bentonite and ethanol is 1:5;

[0246] The mass ratio of the nano-bentonite, coal slag powder and lignin is 10:1:3;

[0247] The inert atmosphere is nitrogen;

[0248] The heating calcination temperature is 820°C.

[0249] The voltage of electrospinning was 16 kV, the receiving distance was fixed at 18 cm, the ambient temperature of the spinning room was 25 °C, and the humidity was 35%.

[0250] The catalyst bed adopts V 2 O 5 / TiO 2 Catalytic denitrification catalyst.

[0251] (4) After the production is completed, the supply of liquefied petroleum gas is stopped, the combustion chamber 3 is cooled by the cooling system 5, and the remaining residues are collected and cleaned, dried, and then collected again to complete the entire production process.

[0252] Example 4

[0253] like Figure 1-4 As shown, this embodiment discloses a method for producing high-activity uranium trioxide by treating a large flux of uranyl nitrate, the steps comprising:

[0254] (1) Fuel gas is introduced into the combustion chamber 3 through the gas supply system 4, causing the fuel gas to undergo a combustion reaction and generate high-temperature gas.

[0255] Wherein, the gas supply system 4 includes a storage tank 03, which is connected to the compressor 02 through a first pipeline 04, and the compressor 02 is connected to the unloading module 01 through a second pipeline. The unloading module 01 is used to obtain liquid-phase gas raw materials or gas-phase gas raw materials from the gas supply station, and the storage tank 03 is connected to the dispersion module 08 through the pipeline 04. The storage tank 03 is respectively connected to the first gasification pressure regulating device 051 and the second gasification pressure regulating device 05 through pipelines, and is respectively connected to the first output terminal 071 and the second output terminal 07 through the first pressure reducing valve group 061 and the second pressure reducing valve group 06. The liquefied petroleum gas is output to the combustion chamber through the first output terminal 071 for gas combustion reaction to generate high-temperature gas, and the liquefied petroleum gas is transported to the heating furnace 28 in the exhaust gas purification system 6 through the second output terminal 07 for combustion and heating;

[0256] The temperature inside the combustion chamber is 1000°C.

[0257] (2) High-temperature gas is introduced into the reaction chamber 2, and a uranyl nitrate solution is transported into the reaction chamber 2 through the feeding system 1, so that the uranyl nitrate solution and the high-temperature gas are contacted and thermally decomposed to generate uranium trioxide and nitrogen oxides, thereby obtaining a powder mixed gas.

[0258] Wherein: the uranyl nitrate solution delivered by the feeding system 1 enters the reaction chamber 2 in the form of spray using an atomizing nozzle;

[0259] The aperture of the atomizing nozzle is 0.8mm and the atomizing angle is 45°;

[0260] The feed concentration of uranyl nitrate solution is 1200 g / L, the feed flow rate is 250 L / h, and the nitric acid concentration in the feed solution is 3.5 mol / L;

[0261] The reaction temperature of reaction chamber 2 is 460°C, and the pressure of reaction chamber 2 is -5KPa.

[0262] (3) The powder mixed gas in the reaction chamber 2 is transported to the powder receiving hopper 8 through the L discharge valve 10. After being filtered by the filter device 7, the gas is introduced into the tail gas purification system 6 to recover nitric acid and convert the nitrogen oxides in the tail gas into nitrogen before being discharged. After sedimentation, the powder is guided to the collection device 9 to obtain the finished uranium trioxide product.

[0263] Among them, the inner diameter of the L discharge valve 10 is 27 mm, the horizontal pipe length of the L discharge valve 10 is 317 mm, the temperature inside the L discharge valve 10 is 465° C., and the inflation rate is 0.6 m3 / h;

[0264] The exhaust gas purification system 6 includes: an exhaust gas inlet 20, a heat exchanger 23, a first absorption tower 24, a second absorption tower 25, a third absorption tower 26, a fourth absorption tower 27, a heating furnace 28, an ammonia inlet 29, an ammonia injection device 210, a catalyst bed 211, a booster fan 21, an exhaust gas detection device 212, a chimney 213, a control valve 22, a pipeline, and a condenser 215; wherein the exhaust gas inlet 20 is connected to the condenser 215 through a pipeline, the condenser 215 is further connected to the heat exchanger 23 through a pipeline, the heat exchanger 23 is connected to the booster fan 21 through a pipeline, and the heat exchanger 23 is connected to the booster fan 21 through a pipeline. connected to the first absorption tower 24, the second absorption tower 25, the third absorption tower 26, and the fourth absorption tower 27, the fourth absorption tower 27 is connected to the heating furnace 28 through a pipeline, the heating furnace 28 is connected to the ammonia injection device 210 through a pipeline, the ammonia injection device 210 is connected to the catalyst bed 211, the catalyst bed 211 is respectively connected to the heat exchanger 23 and the booster fan 21 through pipelines, an exhaust gas detection device 212 is provided between the booster fan 21 and the catalyst bed 211, and the booster fan 21 is connected to the chimney 213 through a pipeline, wherein the pipelines connecting the devices are respectively provided with control valves 22;

[0265] The filter device 7 uses a high-performance filter composite membrane as a filter element. The preparation method of the high-performance filter composite membrane includes the following steps:

[0266] preparing a composite spinning solution;

[0267] Ultrasonic treatment is performed on the composite spinning solution to obtain a pretreated composite spinning solution;

[0268] The spinning solution is subjected to electrostatic spinning and then dried at 80° C. for 20 hours to obtain a high-performance filtration composite membrane as a filter element. The thickness of the high-performance filtration composite membrane is 35 μm.

[0269] The preparation method of the composite spinning solution is as follows:

[0270] Add polystyrene resin to the organic solvent, stir and mix evenly, then add nanocomposite material and N, N', N"-tri[1-(methoxymethyl)propyl]benzene-1,3,5-tricarboxamide respectively, adjust the temperature to 70°C, keep stirring for 30 minutes, and then disperse by ultrasonic for 5 minutes to obtain a composite spinning solution;

[0271] Wherein, the organic solvent is DMF;

[0272] The mass ratio of polystyrene resin and DMF is 14:100;

[0273] The mixed mass ratio of polystyrene resin, nanocomposite material and N,N',N"-tris[1-(methoxymethyl)propyl]benzene-1,3,5-tricarboxamide is 40:2:4.5.

[0274] The preparation method of the nanocomposite material is as follows:

[0275] Firstly, nano-bentonite was added into ethanol and dispersed by ultrasound for 10 min to obtain a dispersion;

[0276] Adding coal slag powder and lignin into the dispersion, stirring for 30 minutes, and drying to obtain a mixture;

[0277] The mixed material is added into a tubular furnace, heated and calcined for 3 hours under the protection of an inert atmosphere, and then naturally cooled to room temperature to obtain a nanocomposite material;

[0278] Among them, the mixing mass ratio of nano-bentonite and ethanol is 1:5.2;

[0279] The mass ratio of nano-bentonite, coal slag powder and lignin is 10:1.5:3.5;

[0280] The inert atmosphere was nitrogen;

[0281] The heating calcination temperature is 830°C.

[0282] The voltage of electrospinning was 16.5 kV, the receiving distance was fixed at 18 cm, the ambient temperature of the spinning room was 25 °C, and the humidity was 35%.

[0283] The catalyst bed adopts V 2 O 5 / TiO 2 Catalytic denitrification catalyst.

[0284] (4) After the production is completed, the supply of liquefied petroleum gas is stopped, the combustion chamber 3 is cooled by the cooling system 5, and the remaining residues are collected and cleaned, dried, and then collected again to complete the entire production process.

[0285] Example 5

[0286] like Figure 1-4 As shown, this embodiment discloses a method for producing high-activity uranium trioxide by treating a large flux of uranyl nitrate, the steps comprising:

[0287] (1) Fuel gas is introduced into the combustion chamber 3 through the gas supply system 4, causing the fuel gas to undergo a combustion reaction and generate high-temperature gas.

[0288] The gas supply system 4 includes a storage tank 03, which is connected to the compressor 02 through a first pipeline 04, and the compressor 02 is connected to the unloading module 01 through a second pipeline 04. The unloading module 01 is used to obtain liquid-phase gas raw materials or gas-phase gas raw materials from the gas supply station; the storage tank 03 is connected to the dispersion module 08 through a fifth pipeline, and the storage tank 03 is respectively connected to the first gasification pressure regulating device 051 and the second gasification pressure regulating device 05 through the pipeline 04 and connected to the first output terminal 071 and the second output terminal 07 through the first pressure reducing valve group 061 and the second pressure reducing valve group 06 respectively, and outputs liquefied petroleum gas to the combustion chamber through the first output terminal 071 for gas combustion reaction to generate high-temperature gas, and transports the liquefied petroleum gas to the heating furnace through the second output terminal 07 for combustion and heating;

[0289] The temperature in the combustion chamber 3 is 1200°C.

[0290] (2) High-temperature gas is introduced into the reaction chamber 2, and a uranyl nitrate solution is transported into the reaction chamber 2 through the feeding system 1, so that the uranyl nitrate solution and the high-temperature gas are contacted and thermally decomposed to generate uranium trioxide and nitrogen oxides, thereby obtaining a powder mixed gas.

[0291] The uranyl nitrate solution delivered by the feeding system 1 is sprayed into the reaction chamber 2 by an atomizing nozzle;

[0292] The aperture of the atomizing nozzle is 0.8mm and the atomizing angle is 45°;

[0293] The feed concentration of uranyl nitrate solution is 1500 g / L, the feed flow rate is 300 L / h, and the nitric acid concentration in the feed solution is 4 mol / L;

[0294] The reaction temperature of reaction chamber 2 is 490°C, and the pressure of reaction chamber 2 is -5KPa.

[0295] (3) The powder mixed gas in the reaction chamber 2 is transported to the powder receiving hopper 8 through the L discharge valve 10. After being filtered by the filter device 7, the gas is introduced into the tail gas purification system 6 to recover nitric acid and convert the nitrogen oxides in the tail gas into nitrogen before being discharged. After sedimentation, the powder is guided to the collection device 9 to obtain the finished uranium trioxide product.

[0296] Among them, the inner diameter of the L discharge valve 10 is 27 mm, the horizontal pipe length of the L discharge valve 10 is 317 mm, the temperature inside the L discharge valve 10 is 465° C., and the inflation rate is 0.6 m3 / h;

[0297] The exhaust gas purification system 6 includes: an exhaust gas inlet 20, a heat exchanger 23, a first absorption tower 24, a second absorption tower 25, a third absorption tower 26, a fourth absorption tower 27, a heating furnace 28, an ammonia inlet 29, an ammonia injection device 210, a catalyst bed 211, a booster fan 21, an exhaust gas detection device 212, a chimney 213, a control valve 22, a pipeline, and a condenser 215; wherein the exhaust gas inlet 20 is connected to the condenser 215 through a pipeline, the condenser 215 is further connected to the heat exchanger 23 through a pipeline, the heat exchanger 23 is connected to the booster fan 21 through a pipeline, and the heat exchanger 23 is connected to the booster fan 21 through a pipeline. connected to the first absorption tower 24, the second absorption tower 25, the third absorption tower 26, and the fourth absorption tower 27, the fourth absorption tower 27 is connected to the heating furnace 28 through a pipeline, the heating furnace 28 is connected to the ammonia injection device 210 through a pipeline, the ammonia injection device 210 is connected to the catalyst bed 211, the catalyst bed 211 is respectively connected to the heat exchanger 23 and the booster fan 21 through pipelines, an exhaust gas detection device 212 is provided between the booster fan 21 and the catalyst bed 211, and the booster fan 21 is connected to the chimney 213 through a pipeline, wherein the pipelines connecting the devices are respectively provided with control valves 22;

[0298] The filter device 7 uses a high-performance filter composite membrane as a filter element. The preparation method of the high-performance filter composite membrane includes the following steps:

[0299] preparing a composite spinning solution;

[0300] Ultrasonic treatment is performed on the composite spinning solution to obtain a pretreated composite spinning solution;

[0301] The spinning solution is subjected to electrostatic spinning and then dried at 80° C. for 20 hours to obtain a high-performance filtration composite membrane having a thickness of 35 μm.

[0302] The preparation method of the composite spinning solution is as follows:

[0303] Add polystyrene resin to the organic solvent, stir and mix evenly, then add nanocomposite material and N, N', N"-tri[1-(methoxymethyl)propyl]benzene-1,3,5-tricarboxamide respectively, adjust the temperature to 70°C, keep stirring for 30 minutes, and then disperse by ultrasonic for 5 minutes to obtain a composite spinning solution;

[0304] Wherein, the organic solvent is DMF;

[0305] The mass ratio of polystyrene resin and DMF is 13:100;

[0306] The mixing mass ratio of polystyrene resin, nanocomposite material and N,N',N"-tri[1-(methoxymethyl)propyl]benzene-1,3,5-tricarboxamide is 40:2:5.

[0307] The preparation method of the nanocomposite material is as follows:

[0308] The nano-bentonite was added into ethanol and dispersed by ultrasonic for 10 min to obtain a dispersion;

[0309] Adding coal slag powder and lignin into the dispersion, stirring for 30 minutes, and drying to obtain a mixture;

[0310] The mixed material is added into a tubular furnace, heated and calcined for 3 hours under the protection of an inert atmosphere, and then naturally cooled to room temperature to obtain a nanocomposite material;

[0311] Among them, the mixing mass ratio of nano-bentonite and ethanol is 1:5.8;

[0312] The mass ratio of nano-bentonite, coal slag powder, and lignin is 10:1.8:4;

[0313] The inert atmosphere was nitrogen;

[0314] The heating calcination temperature is 850°C.

[0315] The voltage of electrospinning was 17 kV, the receiving distance was fixed at 18 cm, the ambient temperature of the spinning room was 25 °C, and the humidity was 35%.

[0316] The catalyst bed adopts V 2 O 5 / TiO 2 Catalytic denitrification catalyst.

[0317] (4) After the production is completed, the supply of liquefied petroleum gas is stopped, the combustion chamber 3 is cooled by the cooling system 5, and the remaining residues are collected and cleaned, dried, and then collected again to complete the entire production process.

[0318] Example 6

[0319] like Figure 1-4 As shown, this embodiment discloses a method for producing high-activity uranium trioxide by treating a large flux of uranyl nitrate, the steps comprising:

[0320] (1) Fuel gas is introduced into the combustion chamber 3 through the gas supply system 4, causing the fuel gas to undergo a combustion reaction and generate high-temperature gas.

[0321] The gas supply system 4 includes a storage tank 03, which is connected to the compressor 02 through a first pipeline 04, and the compressor 02 is connected to the unloading module 01 through a second pipeline. The unloading module 01 is used to obtain liquid-phase gas raw materials or gas-phase gas raw materials from the gas supply station. The storage tank 03 is connected to the dispersing module 08 through a fifth pipeline, and the storage tank 03 is respectively connected to the first gasification pressure regulating device 051 and the second gasification pressure regulating device 05 through pipelines, and is respectively connected to the first output terminal 071 and the second output terminal 07 through the first pressure reducing valve group 061 and the second pressure reducing valve group 06, and outputs liquefied petroleum gas to the combustion chamber 3 through the first output terminal 071 for gas combustion reaction to generate high-temperature gas, and transports the liquefied petroleum gas to the heating furnace through the second output terminal 07 for combustion and heating;

[0322] The temperature in the combustion chamber is 900°C;

[0323] (2) High-temperature gas is introduced into the reaction chamber 2, and a uranyl nitrate solution is delivered into the reaction chamber through the feeding system 1, so that the uranyl nitrate solution and the high-temperature gas are contacted and thermally decomposed to generate uranium trioxide and nitrogen oxides, thereby obtaining a powder mixed gas.

[0324] The uranyl nitrate solution delivered by the feeding system 1 is sprayed into the reaction chamber 2 by an atomizing nozzle;

[0325] The aperture of the atomizing nozzle is 0.8mm and the atomizing angle is 45°;

[0326] The feed concentration of uranyl nitrate solution is 1800 g / L, the feed flow rate is 350 L / h, and the nitric acid concentration in the feed solution is 4 mol / L;

[0327] The reaction temperature of reaction chamber 2 is 470°C, and the pressure of reaction chamber 2 is -5KPa.

[0328] (3) The powder mixed gas in the reaction chamber 2 is transported to the powder receiving hopper 8 through the L discharge valve 10. After being filtered by the filter device 7, the gas is introduced into the tail gas purification system 6 to recover nitric acid and convert the nitrogen oxides in the tail gas into nitrogen before being discharged. After sedimentation, the powder is guided to the collection device 9 to obtain the finished uranium trioxide product.

[0329] Among them, the inner diameter of the L discharge valve 10 is 27 mm, the horizontal pipe length of the L discharge valve 10 is 317 mm, the temperature inside the L discharge valve 10 is 465° C., and the inflation rate is 0.6 m3 / h;

[0330] The exhaust gas purification system 6 includes: an exhaust gas inlet 20, a heat exchanger 23, a first absorption tower 24, a second absorption tower 25, a third absorption tower 26, a fourth absorption tower 27, a heating furnace 28, an ammonia inlet 29, an ammonia injection device 210, a catalyst bed 211, a booster fan 21, an exhaust gas detection device 212, a chimney 213, a control valve 22, a pipeline, and a condenser 215; wherein the exhaust gas inlet 20 is connected to the condenser 215 through a pipeline, the condenser 215 is further connected to the heat exchanger 23 through a pipeline, the heat exchanger 23 is connected to the booster fan 21 through a pipeline, and the heat exchanger 23 is connected to the booster fan 21 through a pipeline. connected to the first absorption tower 24, the second absorption tower 25, the third absorption tower 26, and the fourth absorption tower 27, the fourth absorption tower 27 is connected to the heating furnace 28 through a pipeline, the heating furnace 28 is connected to the ammonia injection device 210 through a pipeline, the ammonia injection device 210 is connected to the catalyst bed 211, the catalyst bed 211 is respectively connected to the heat exchanger 23 and the booster fan 21 through pipelines, an exhaust gas detection device 212 is provided between the booster fan 21 and the catalyst bed 211, and the booster fan 21 is connected to the chimney 213 through a pipeline, wherein the pipelines connecting the devices are respectively provided with control valves 22;

[0331] The filter device 7 uses a high-performance filter composite membrane as a filter element. The preparation method of the high-performance filter composite membrane includes the following steps:

[0332] preparing a composite spinning solution;

[0333] Ultrasonic treatment is performed on the composite spinning solution to obtain a pretreated composite spinning solution;

[0334] The spinning solution is subjected to electrostatic spinning and then dried at 80° C. for 20 hours to obtain a high-performance filtration composite membrane having a thickness of 35 μm.

[0335] The preparation method of the composite spinning solution is as follows:

[0336] Add polystyrene resin to the organic solvent, stir and mix evenly, then add nanocomposite material and N, N', N"-tri[1-(methoxymethyl)propyl]benzene-1,3,5-tricarboxamide respectively, adjust the temperature to 70°C, keep stirring for 30 minutes, and then disperse by ultrasonic for 5 minutes to obtain a composite spinning solution;

[0337] Wherein, the organic solvent is DMF;

[0338] The mass ratio of polystyrene resin and DMF is 14:100;

[0339] The mixing mass ratio of polystyrene resin, nanocomposite material and N,N',N"-tri[1-(methoxymethyl)propyl]benzene-1,3,5-tricarboxamide is 40:2:4.

[0340] The preparation method of the nanocomposite material is as follows:

[0341] The nano-bentonite was added into ethanol and dispersed by ultrasonic for 10 min to obtain a dispersion;

[0342] Adding coal slag powder and lignin into the dispersion, stirring for 30 minutes, and drying to obtain a mixture;

[0343] The mixed material is added into a tubular furnace, heated and calcined for 3 hours under the protection of an inert atmosphere, and then naturally cooled to room temperature to obtain a nanocomposite material;

[0344] Among them, the mixing mass ratio of nano-bentonite and ethanol is 1:5.8;

[0345] The mass ratio of nano-bentonite, coal slag powder, and lignin is 10:1.8:4;

[0346] The inert atmosphere was nitrogen;

[0347] The heating calcination temperature is 850°C.

[0348] The voltage of electrospinning was 17 kV, the receiving distance was fixed at 18 cm, the ambient temperature of the spinning room was 25 °C, and the humidity was 35%.

[0349] The catalyst bed adopts V 2 O 5 / TiO 2 Catalytic denitrification catalyst.

[0350] (4) After the production is completed, the supply of liquefied petroleum gas is stopped, the combustion chamber 3 is cooled by the cooling system 5, and the remaining residues are collected and cleaned, dried, and then collected again to complete the entire production process.

[0351] Example 7

[0352] like Figure 1-4 As shown, this embodiment discloses a method for producing high-activity uranium trioxide by treating a large flux of uranyl nitrate, the steps comprising:

[0353] (1) Fuel gas is introduced into the combustion chamber 2 through the gas supply system 4, causing the fuel gas to undergo a combustion reaction and generate high-temperature gas.

[0354] Wherein, the gas supply system 4 includes a storage tank 03, which is connected to the compressor 02 through a first pipeline 04, and the compressor 02 is connected to the unloading module 01 through a second pipeline. The unloading module 01 is used to obtain liquid-phase gas raw materials or gas-phase gas raw materials from the gas supply station, and the storage tank 03 is connected to the dispersion module 08 through a fifth pipeline. The storage tank 03 is respectively connected to the first gasification pressure regulating device 051 and the second gasification pressure regulating device 05 through pipelines, and is respectively connected to the first output terminal 071 and the second output terminal 07 through the first pressure reducing valve group 061 and the second pressure reducing valve group 06. The liquefied petroleum gas is output to the combustion chamber through the first output terminal 071 for gas combustion reaction to generate high-temperature gas, and the liquefied petroleum gas is transported to the heating furnace through the second output terminal 07 for combustion and heating;

[0355] The temperature in the combustion chamber 3 is 1400°C.

[0356] (2) High-temperature gas is introduced into the reaction chamber 2, and a uranyl nitrate solution is delivered into the reaction chamber through the feeding system 1, so that the uranyl nitrate solution and the high-temperature gas are contacted and thermally decomposed to generate uranium trioxide and nitrogen oxides, thereby obtaining a powder mixed gas.

[0357] The uranyl nitrate solution delivered by the feeding system is sprayed into the reaction chamber 2 by an atomizing nozzle;

[0358] The aperture of the atomizing nozzle is 0.8mm and the atomizing angle is 45°;

[0359] The feed concentration of uranyl nitrate solution is 2000 g / L, the feed flow rate is 400 L / h, and the nitric acid concentration in the feed solution is 5 mol / L;

[0360] The reaction temperature of reaction chamber 2 is 500° C., and the pressure of reaction chamber 2 is -5 KPa.

[0361] (3) The powder mixed gas in the reaction chamber 2 is transported to the powder receiving hopper 8 through the L discharge valve 10. After being filtered by the filter device 7, the gas is introduced into the tail gas purification system 6 to recover nitric acid and convert the nitrogen oxides in the tail gas into nitrogen before being discharged. After sedimentation, the powder is guided to the collection device 9 to obtain the finished uranium trioxide product.

[0362] Among them, the inner diameter of the L discharge valve 10 is 27 mm, the horizontal pipe length of the L discharge valve 10 is 317 mm, the temperature inside the L discharge valve 10 is 465°C, and the inflation rate is 0.6 m3 / h;

[0363] The exhaust gas purification system 6 includes: an exhaust gas inlet 20, a heat exchanger 23, a first absorption tower 24, a second absorption tower 25, a third absorption tower 26, a fourth absorption tower 27, a heating furnace 28, an ammonia inlet 29, an ammonia injection device 210, a catalyst bed 211, a booster fan 21, an exhaust gas detection device 212, a chimney 213, a control valve 22, a pipeline, and a condenser 215; wherein the exhaust gas inlet 20 is connected to the condenser 215 through a pipeline, the condenser 215 is further connected to the heat exchanger 23 through a pipeline, the heat exchanger 23 is connected to the booster fan 21 through a pipeline, and the heat exchanger 23 is connected to the booster fan 21 through a pipeline. connected to the first absorption tower 24, the second absorption tower 25, the third absorption tower 26, and the fourth absorption tower 27, the fourth absorption tower 27 is connected to the heating furnace 28 through a pipeline, the heating furnace 28 is connected to the ammonia injection device 210 through a pipeline, the ammonia injection device 210 is connected to the catalyst bed 211, the catalyst bed 211 is respectively connected to the heat exchanger 23 and the booster fan 21 through pipelines, an exhaust gas detection device 212 is provided between the booster fan 21 and the catalyst bed 211, and the booster fan 21 is connected to the chimney 213 through a pipeline, wherein the pipelines connecting the devices are respectively provided with control valves 22;

[0364] The filter device 7 uses a high-performance filter composite membrane as a filter element. The preparation method of the high-performance filter composite membrane includes the following steps:

[0365] a. preparing a composite spinning solution;

[0366] b. subjecting the composite spinning solution to ultrasonic treatment to obtain a pretreated composite spinning solution;

[0367] c The spinning solution is subjected to electrostatic spinning and then dried at 80°C for 20 hours to obtain a high-performance filtration composite membrane. The thickness of the high-performance filtration composite membrane is 35 μm.

[0368] The preparation method of the composite spinning solution is as follows:

[0369] Add polystyrene resin to the organic solvent, stir and mix evenly, then add nanocomposite material and N, N', N"-tri[1-(methoxymethyl)propyl]benzene-1,3,5-tricarboxamide respectively, adjust the temperature to 70°C, keep stirring for 30 minutes, and then disperse by ultrasonic for 5 minutes to obtain a composite spinning solution;

[0370] Wherein, the organic solvent is DMF;

[0371] The mass ratio of polystyrene resin and DMF is 14:100;

[0372] The mixing mass ratio of polystyrene resin, nanocomposite material and N,N',N"-tri[1-(methoxymethyl)propyl]benzene-1,3,5-tricarboxamide is 40:2:5.

[0373] The preparation method of the nanocomposite material is as follows:

[0374] The nano-bentonite was added into ethanol and dispersed by ultrasonic for 10 min to obtain a dispersion;

[0375] Adding coal slag powder and lignin into the dispersion, stirring for 30 minutes, and drying to obtain a mixture;

[0376] The mixed material is added into a tubular furnace, heated and calcined for 3 hours under the protection of an inert atmosphere, and then naturally cooled to room temperature to obtain a nanocomposite material;

[0377] Among them, the mixing mass ratio of nano-bentonite and ethanol is 1:6;

[0378] The mass ratio of nano-bentonite, coal slag powder, and lignin is 10:2:5;

[0379] The inert atmosphere was nitrogen;

[0380] The heating calcination temperature is 860°C.

[0381] The voltage of electrospinning was 18 kV, the receiving distance was fixed at 18 cm, the ambient temperature of the spinning room was 25 °C, and the humidity was 35%.

[0382] The catalyst bed adopts V 2 O 5 / TiO 2 Catalytic denitrification catalyst.

[0383] (4) After the production is completed, the supply of liquefied petroleum gas is stopped, the combustion chamber 3 is cooled by the cooling system 5, and the remaining residues are collected and cleaned, dried, and then collected again to complete the entire production process.

[0384] Comparative Example 1:

[0385] The difference from Example 3 is that the feeding method adopts the direct feeding method, and the other technical solutions remain unchanged.

[0386] Comparative Example 2:

[0387] The difference from Example 3 is that no nanocomposite material is added during the preparation of the high-performance filtration composite membrane, and the rest of the technical solutions remain unchanged.

[0388] Comparative Example 3:

[0389] The existing fluidized bed denitrification method is adopted, refer to patent publication number: CN213077996U.

[0390] Test 1:

[0391] The products, condensates and tail gases in Examples 3-7 and Comparative Examples 1-3 were tested respectively, and the results are shown in Table 1.

[0392] Table 1

[0393]

[0394]

[0395] As can be seen from Table 1, the specific surface area of ​​uranium trioxide obtained by the method of the present invention is relatively large, which can reach more than 17.9, while the product generated by directly introducing uranyl nitrate solution in Comparative Example 1 not only has a small specific surface area of ​​only 2.5m2 / g, but also because the thermal decomposition reaction of large-flux uranyl nitrate requires sufficient heat and is fully in contact with high-temperature fuel gas to completely react and generate highly active uranium oxide products, the direct feeding method of Comparative Example 1 will result in insufficient heat in the thermal decomposition reaction process, insufficient contact between uranyl nitrate and fuel gas, resulting in partial raw materials not reacting completely, which shows that the method of the present invention can significantly increase the specific surface area of ​​uranium trioxide products; at the same time, through the method proposed by the present invention, the nitric acid recovery rate can be made above 50%, the tail gas NOx outlet concentration is less than 240mg / Nm3 (emission standard), and the ammonia escape is controlled below 3ppm (ammonia escape standard), which can solve the problem that the prior art cannot handle high-flux uranyl nitrate and nitrogen oxides seriously exceed the standard. Among them, the performance of the filter membrane does not affect the product specific surface area, nitric acid recovery rate and tail gas purification level.

[0396] Test 2:

[0397] The method described in Example 3 was adopted, and the aperture of the atomizing nozzle was changed to compare the effects of different atomizing nozzle apertures on the specific surface area of ​​the prepared uranium trioxide. The results are shown in Table 2.

[0398] Table 2

[0399] Atomizing nozzle aperture / mm Specific surface area m2 / g 0.1 9.5 0.2 14.2 0.4 15.7 0.6 17.5 0.8 19.2 1.0 18.0 1.2 15.1 1.3 10.1

[0400] It can be seen from Table 2 that within the aperture range of the atomizing nozzle selected by the method of the present invention, the specific surface area of ​​the uranium trioxide product is relatively large, that is, the method of the present invention can increase the specific surface area of ​​the uranium trioxide product.

[0401] Test 3:

[0402] The method described in Example 3 was adopted, and the atomization angle was changed to compare the effects of different atomization angles on the specific surface area and average particle size of the prepared uranium trioxide. The results are shown in Table 4.

[0403] Table 3

[0404] Atomization angle° Specific surface area m2 / g Average particle size μm 38 12.2 70 40 17.3 76 45 19.2 78 50 16.5 80 55 14.3 82 60 13.0 86 65 11.6 90 67 9.6 94

[0405] It can be seen from Table 3 that different atomization angles have different effects on the specific surface area of ​​uranium trioxide. Within the atomization angle range selected by the method of the present invention, the specific surface area of ​​uranium trioxide products is relatively large, which can reach more than 11.6m2 / g, and when the atomization angle is 45°, the specific surface area of ​​uranium trioxide is the largest; the average particle size of uranium trioxide products is controlled at 50-100μm, which can be directly used in subsequent purification processes, thereby avoiding the hydration reduction process. Outside the atomization angle range selected by the method of the present invention, the specific surface area is small, the product activity is low, and it cannot meet the downstream process requirements.

[0406] Test 4:

[0407] The method described in Example 3 was adopted, and the reaction chamber temperature (ie, reaction temperature) was changed to compare the effects of different reaction chamber temperatures on the obtained uranium trioxide product. The results are shown in Table 4.

[0408] Table 4

[0409]

[0410]

[0411] As can be seen from Table 4, within the reaction chamber temperature range selected by the present invention, the specific surface area of ​​the uranium trioxide product is relatively large, and the mass fraction of uranium trioxide is greater than 97%, and the water content is less than 1%, meeting the product index requirements. When the temperature in the reaction chamber is 480°C, the obtained uranium trioxide has the largest specific surface area, high purity and low water content. Outside the reaction chamber temperature range selected by the present application, if the reaction temperature is low, the reaction is incomplete and the water content is high, and the high reaction temperature will lead to lower product activity and specific surface area.

[0412] Test 5:

[0413] The filtration efficiencies of the filtration devices in Examples 3-7 and Comparative Examples 1-3 were tested respectively, and the results are shown in Table 5.

[0414] Table 5

[0415] Average U content of 24h denitrification condensate μgU / L Example 3 45.1 Example 4 42.8 Example 5 43.3 Example 6 47.2 Example 7 42.5 Comparative Example 1 86.6 Comparative Example 2 180.6 Comparative Example 3 355.0

[0416] It can be seen from Table 5 that the average U content of the 24h denitration condensate of Examples 3-7 is less than or equal to 47.2 μgU / L. Compared with Comparative Examples 1-3, the filtration efficiency is significantly higher. It can be seen that the filtration device used in the method of the present invention can efficiently filter uranium oxide particles. Since the uranium oxide powder prepared by the present invention has a small particle size, part of the uranium oxide will pass through the filter membrane used in the traditional method.

[0417] It is to be understood that the above embodiments are merely exemplary embodiments used to illustrate the principles of the present invention, but the present invention is not limited thereto. For those of ordinary skill in the art, various modifications and improvements can be made without departing from the spirit and essence of the present invention, and these modifications and improvements are also considered to be within the scope of protection of the present invention.

Claims

1. A method for producing high-activity uranium trioxide by treating large-flux uranyl nitrate, characterized in that: include: (1) The gas is introduced into the combustion chamber (3) through the gas supply system (4), so that the gas undergoes a combustion reaction to generate high-temperature gas. The gas supply system comprises a storage tank (03), a compressor (02), an unloading module (01), a gasification pressure regulating device and a pressure reducing valve group, the storage tank is connected to the compressor via a first pipeline, the compressor is connected to the unloading module via a second pipeline, the unloading module is connected to the storage tank via a third pipeline (04), the gasification pressure regulating device is connected to the storage tank via a fourth pipeline, the pressure reducing valve group is connected to the gasification pressure regulating device, and the combustion chamber is connected to the pressure reducing valve group; (2) introducing high temperature gas into the reaction chamber (2), and conveying uranyl nitrate solution into the reaction chamber, so that the uranyl nitrate solution and the high temperature gas come into contact with each other and undergo a thermal decomposition reaction to generate uranium trioxide and nitrogen oxides, thereby obtaining a powder mixed gas; (3) The powder mixed gas in the reaction chamber is transported to the powder receiving hopper through the L discharge valve (10). After being filtered by the filter device, the gas is introduced into the tail gas purification system (6) to recover nitric acid and convert nitrogen oxides in the tail gas into nitrogen gas before being discharged. After precipitation, the powder is led out to the collection device to obtain the finished uranium trioxide. The exhaust gas purification system specifically comprises an absorption tower, an ammonia spraying device (210), a catalyst bed (211), a booster fan (21), an exhaust gas detection device (212) and a chimney (213); the absorption tower is connected to the filtering device, the ammonia spraying device is connected to the absorption tower, the catalyst bed is connected to the ammonia spraying device, the booster fan is connected to the catalyst bed, and the exhaust gas detection device and the chimney are respectively connected to the booster fan.

2. The method for producing high-activity uranium trioxide by treating large-flux uranyl nitrate according to claim 1, characterized in that: The fuel gas is liquefied petroleum gas.

3. The method for producing high-activity uranium trioxide for processing large-flux uranyl nitrate according to claim 1, characterized in that: The uranyl nitrate solution is sprayed into the reaction chamber in a spraying manner using an atomizing nozzle.

4. The method for producing high-activity uranium trioxide by treating large-flux uranyl nitrate according to claim 3, characterized in that: The aperture of the atomizing nozzle is 0.2-1.2 mm, and the atomizing angle is 40-65°.

5. The method for producing high-activity uranium trioxide by treating large-flux uranyl nitrate according to claim 1, characterized in that: The feed concentration of the uranyl nitrate solution is 1000-2000 g / L, the feed flow rate is 200-400 L / h, and the nitric acid concentration in the uranyl nitrate solution is 3-5 mol / L.

6. The method for producing high-activity uranium trioxide by treating large-flux uranyl nitrate according to claim 1, characterized in that: The reaction temperature in the reaction chamber is controlled at 440-500° C., and the pressure in the reaction chamber is controlled at -5 kPa.

7. The method for producing high-activity uranium trioxide by treating large-flux uranyl nitrate according to claim 1, characterized in that: The filtering device uses a high-performance filtering composite membrane as a filtering core. The high performance filtration composite membrane is prepared in the following manner: preparing a composite spinning solution; Ultrasonic treatment is performed on the composite spinning solution to obtain a pretreated composite spinning solution; The spinning solution is subjected to electrostatic spinning to obtain a composite spinning membrane; The composite spinning membrane is dried at 80° C. for 20 hours to obtain the high-performance filtration composite membrane.

8. The method for producing high-activity uranium trioxide by treating large-flux uranyl nitrate according to claim 7, characterized in that: The composite spinning solution is prepared in the following manner: Adding polystyrene resin to an organic solvent, stirring and mixing evenly, then adding nanocomposite material and N, N', N"-tris[1-(methoxymethyl)propyl]benzene-1,3,5-tricarboxamide respectively, adjusting the temperature to 70°C, keeping the temperature and stirring for 30 minutes, and then performing ultrasonic dispersion for 5 minutes to obtain the composite spinning solution; Wherein, the organic solvent is DMF; The mass ratio of polystyrene resin and DMF is 12-15:100; The mixing mass ratio of polystyrene resin, nano composite material and N, N', N"-tris[1-(methoxymethyl)propyl]benzene-1,3,5-tricarboxamide is 40:1-3:4-5.

9. The method for producing high-activity uranium trioxide by treating large-flux uranyl nitrate according to claim 8, characterized in that: The nanocomposite material is prepared in the following manner: The nano-bentonite was added into ethanol and dispersed by ultrasonic for 10 min to obtain a dispersion; Adding coal slag powder and lignin into the dispersion, stirring for 30 minutes, and drying to obtain a mixture; The mixed material is added into a tubular furnace, heated and calcined for 3 hours under the protection of an inert atmosphere, and then naturally cooled to room temperature to obtain the nanocomposite material; Wherein, the mixing mass ratio of the nano-bentonite and ethanol is 1:5-6; The mass ratio of the nano-bentonite, coal slag powder and lignin is 10:1-2:3-5; The inert atmosphere is nitrogen; The heating calcination temperature is 820-860°C.

10. The high-activity uranium trioxide production equipment for processing large-flux uranyl nitrate according to claim 7, characterized in that: The voltage of the electrostatic spinning was 16-18 kV, the receiving distance was fixed at 18 cm, the ambient temperature of the spinning room was 25° C., and the humidity was 35%.

11. The method for producing high-activity uranium trioxide for processing large-flux uranyl nitrate according to claim 1, characterized in that: The absorption tower is a plurality of absorption towers connected in series in sequence, and each absorption tower is provided with Y-250 type 304 stainless steel structured packing.

12. The high-activity uranium trioxide production equipment for processing large-flux uranyl nitrate according to claim 1, characterized in that: The catalyst bed layer adopts V2O5 / TiO2 catalytic denitration catalyst.

13. The method for producing high-activity uranium trioxide by treating large-flux uranyl nitrate according to any one of claims 1 to 12, characterized in that: The method further comprises: Before the gas filtered by the filter device enters the absorption tower, the gas filtered by the filter device is first condensed, the condensed non-condensable gas is heat exchanged with the gas after the catalyst bed reaction, and then the non-condensable gas after the heat exchange is passed into the absorption tower to form nitric acid; Before the gas treated in the absorption tower enters the catalyst bed, the tail gas after the nitric acid is recovered in the absorption tower is first heated, and then introduced into the ammonia injection device to mix with ammonia and then introduced into the catalyst bed for catalytic reaction to form nitrogen.

14. A high-activity uranium trioxide production device for processing large-flux uranyl nitrate, characterized in that: It comprises a feeding system (1), a reaction system, a gas supply system (4), and an exhaust gas purification system (6), wherein: The feeding system is connected to the reaction system and is used to deliver the uranyl nitrate solution to the reaction system; The gas supply system is connected to the reaction system and is used to introduce fuel gas into the reaction system. It specifically includes a storage tank (03), a compressor (02), an unloading module (01), a gasification pressure regulating device and a pressure reducing valve group. The storage tank is connected to the compressor via a first pipeline, the compressor is connected to the unloading module via a second pipeline, the unloading module is also connected to the storage tank via a third pipeline (04), the gasification pressure regulating device is connected to the storage tank via a fourth pipeline, and the pressure reducing valve group is connected to the gasification pressure regulating device; The reaction system is used to receive fuel gas and uranyl nitrate solution and to cause combustion reaction of the fuel gas to generate high-temperature gas, so that the uranyl nitrate solution and the high-temperature gas come into contact and then undergo thermal decomposition reaction to generate uranium trioxide and nitrogen oxides. The reaction system specifically comprises a combustion chamber (3), a reaction chamber (2), a powder receiving hopper (8), a filtering device (7) and a collecting device (9), wherein the combustion chamber is connected to a pressure reducing valve group in a gas supply system, the reaction chamber is connected to the combustion chamber and the feeding system respectively, the reaction chamber is provided with an L discharge valve (10), the powder receiving hopper is connected to the reaction chamber via the L discharge valve, and the filtering device and the collecting device are connected to the powder receiving hopper respectively; The exhaust gas purification system is connected to the reaction system and is used to perform deep purification treatment on the exhaust gas discharged from the reaction system. It specifically comprises an absorption tower, an ammonia spraying device (210), a catalyst bed (211), a booster fan (21), an exhaust gas detection device (212) and a chimney (213). The absorption tower is connected to the filtering device in the reaction system, the ammonia spraying device is connected to the absorption tower, the catalyst bed is connected to the ammonia spraying device, the booster fan is connected to the catalyst bed, and the exhaust gas detection device and the chimney are respectively connected to the booster fan.

15. The high-activity uranium trioxide production equipment for processing large-flux uranyl nitrate according to claim 14, characterized in that: The gas supply system also includes a dispersing module (08), which is connected to the storage tank and has a temperature-controlled gasifier.

16. The high-activity uranium trioxide production equipment for processing large-flux uranyl nitrate according to claim 14, characterized in that: The tail end of the feeding system is provided with an atomizing nozzle so that the transported uranyl nitrate solution enters the reaction chamber in a spraying manner.

17. The high-activity uranium trioxide production equipment for processing large-flux uranyl nitrate according to claim 16, characterized in that: The aperture of the atomizing nozzle is 0.8 mm, and the atomizing angle is 45°.

18. The high-activity uranium trioxide production equipment for processing large-flux uranyl nitrate according to claim 14, characterized in that: The filtering device adopts the high-performance filtering composite membrane as claimed in claim 7 as the filtering core, and the specific surface area of ​​the high-performance filtering composite membrane is 8-20m 2 / g.

19. The high-activity uranium trioxide production equipment for processing large-flux uranyl nitrate according to claim 14, characterized in that: The absorption tower comprises a first absorption tower (24), a second absorption tower (25), a third absorption tower (26) and a fourth absorption tower (27), The first absorption tower, the second absorption tower, the third absorption tower and the fourth absorption tower are arranged in series in sequence, the first absorption tower is connected to the filtering device in the reaction system, the fourth absorption tower is connected to the ammonia injection device, and the first absorption tower, the second absorption tower, the third absorption tower and the fourth absorption tower are all provided with Y-250 type 304 stainless steel structured packing.

20. The high-activity uranium trioxide production equipment for processing large-flux uranyl nitrate according to claim 14, characterized in that: The catalyst bed layer adopts V2O5 / TiO2 catalytic denitration catalyst.

21. The high-activity uranium trioxide production equipment for processing large-flux uranyl nitrate according to any one of claims 14 to 20, characterized in that: The tail gas purification system further comprises a condenser (215), a heat exchanger (23) and a heating furnace (28). The absorption tower is connected to the outlet end of the first channel of the heat exchanger, the inlet end of the first channel of the heat exchanger is connected to the condenser, and the condenser is connected to the filtering device in the reaction system; The ammonia spraying device is connected to a heating furnace, and the heating furnace is further connected to an absorption tower.

22. The high-activity uranium trioxide production equipment for processing large-flux uranyl nitrate according to claim 21, characterized in that: The heating furnace is connected to a pressure reducing valve group in a gas supply system to allow gas to flow in.

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