Ammonia catalytic cracking device based on plasma assistance

Abstract

The invention discloses an ammonia catalytic cracking device based on plasma assistance, which relates to the technical field of low-pressure reaction containers, and comprises a plasma high-voltage power supply, an outer cylinder, an inner cylinder, a rotating shaft and an impeller group, the front end and the rear end of the inner cylinder are respectively communicated with the air inlet and the air outlet of the outer cylinder; the front end of the rotating shaft is rotationally connected with the front end surface of the outer cylinder; an impeller group is fixedly arranged on the rotating shaft in the inner cylinder; the positive electrode of the plasma high-voltage power supply is electrically communicated with the rotating shaft and the impeller group, and the negative electrode is electrically communicated with the inner cylinder; the outer cylinder is grounded and electrically communicated with the inner cylinder. The ammonia gas is cracked and heated by high-voltage discharge, the catalyst is heated by heat generated by discharge, secondary thermal cracking of the ammonia is promoted by the catalytic action of the catalyst, the ammonia gas is efficiently cracked into an ammonia-hydrogen mixed gas for subsequent proportioning or purification, and the problem that the ammonia is difficult to apply as a fuel is solved; the device is simple and compact in structure, easy to disassemble and assemble and convenient to use and maintain.

Description

Technical Field

[0001] The invention relates to the technical field of low-pressure reaction vessels, and in particular to a device for cracking ammonia. Background Art

[0002] Hydrogen energy is a secondary clean energy that has been developed and utilized at an accelerated pace in recent years. Hydrogen production from renewable energy can achieve large-scale consumption of renewable energy such as solar energy and wind energy while obtaining hydrogen energy, but its large-scale application still faces the problem of hydrogen energy storage and transportation, which is difficult to break through in the short term.

[0003] Ammonia as a hydrogen storage medium has advantages over hydrogen, such as high energy density, easy liquefaction, easy storage and transportation, and has advantages over gasoline, such as higher octane number and good anti-knock performance, and has good application prospects. However, ammonia as a fuel also has some disadvantages, such as high flash point (651℃), high ignition energy (8 mJ), low flame combustion speed (10cm / s) and low calorific value (18.8MJ / kg), which limit the large-scale production and application of ammonia fuel.

[0004] In order to solve the above problems, an ammonia-hydrogen synthesis-cracking method has been proposed, that is, using renewable energy to produce hydrogen to synthesize ammonia, after transporting the ammonia to the destination, the ammonia is cracked into an ammonia-hydrogen mixed gas containing a certain hydrogen concentration through an ammonia cracking device, and the ammonia-hydrogen mixed gas is further proportioned or purified to produce hydrogen for use.

[0005] Through the search of prior art, the following known technical solutions exist for plasma-assisted ammonia combustion catalytic cracking devices: Prior art 1: A compact and efficient magnetically enhanced plasma-assisted ammonia cracking system Application number: CN202221569317.3, application date: 2022-06-22, publication (announcement) date: 2022-11-08.

[0006] Prior art 1 discloses a compact and efficient magnetically enhanced plasma-assisted ammonia cracking system, including a magnetically enhanced plasma-assisted burner, a heat pipe, a cracking pipe, a heat exchange fin, a catalyst bed, a flow guide pipe, an exhaust gas treatment end, a head, a mixed gas outlet end, a cooling separation chamber, an ammonia hydrogen supply end, a liquid ammonia recovery end, a liquid ammonia tank, a liquid ammonia pump, a liquid phase pressure reducing valve, and an ammonia import interface; the plasma-assisted burner is inserted and arranged inside the heat pipe, the cracking pipe is arranged outside the heat pipe, and the flow guide pipe is arranged outside the cracking pipe; a permanent magnet is placed outside the plasma-assisted burner. The utility model utilizes magnetically enhanced plasma-assisted ammonia combustion to heat and crack ammonia, thereby improving the stability of plasma generation and the concentration of active groups in the plasma, improving the ammonia combustion efficiency, and reducing the size and weight of the entire device, making it more compact and efficient.

[0007] Prior art 2: A device for catalytic cracking of ammonia Application number: CN202410514075.5, application date: 2024-04-26, publication (announcement) date: 2024-07-30.

[0008] Prior art 2 discloses a device for catalytic cracking of ammonia, including a cracking device and its control system. The cracking device includes a cracker and a pipeline system; the pipeline system includes a primary air branch, a secondary air branch, a combustion ammonia branch and a cracking ammonia branch; the air of the primary air branch and the secondary air branch and the ammonia of the combustion ammonia branch are introduced into the plasma-assisted ammonia combustion heat exchange section for plasma-assisted ammonia combustion, and the ammonia of the cracking ammonia branch is introduced into the cracking chamber of the cracker for catalytic ammonia cracking; the cracking device control system monitors the temperature in the cracking device and the hydrogen concentration of the ammonia-hydrogen mixture in the outlet buffer tank, and by adjusting the flow of ammonia and air introduced into the plasma-assisted ammonia combustion heat exchange section, the cracker works in a set state, so that the cracking device can stably output an ammonia-hydrogen mixture of a specific temperature, pressure and hydrogen concentration, and the ammonia-hydrogen mixture can be introduced into the engine system for use.

[0009] However, both the prior art 1 and the prior art 2 use the heat generated by plasma-assisted ammonia combustion for catalytic cracking of ammonia, and both require a separate channel for ammonia combustion and corresponding intake pipes and accessories for burning ammonia and air, and are also required to be equipped with sufficient heat exchange components. The structure is complex, and the combustion control is difficult, which makes it difficult to control the stability of the cracking temperature.

[0010] Through the above search, it is found that the above technical solutions do not affect the novelty of the present invention; and the mutual combination of the above prior arts does not destroy the creativity of the present invention. Summary of the invention

[0011] In order to avoid the above-mentioned deficiencies in the prior art, the present invention provides a plasma-assisted ammonia catalytic cracking device.

[0012] The present invention adopts the following technical solution to solve the technical problem: a plasma-assisted ammonia catalytic cracking device, an outer cylinder as a reaction container, with an air inlet and an air outlet, including a plasma high-voltage power supply, an inner cylinder, a rotating shaft and an impeller group, and the front end surface of the outer cylinder is insulated; In actual configuration, the front end surface of the outer cylinder is preferably made of an insulating material such as polyetheretherester PEEK that meets relevant performance requirements; The inner cylinder is inserted into the outer cylinder, and its front end and rear end are respectively connected to the air inlet and the air outlet; the rotating shaft is located in the outer cylinder and the inner cylinder, and its front end is rotatably mounted and connected to the front end surface of the outer cylinder, and an impeller assembly is fixedly mounted on it in the inner cylinder; The positive electrode of the plasma high voltage power supply is electrically connected to the rotating shaft and the impeller assembly, and the negative electrode is electrically connected to the inner cylinder; the outer cylinder is grounded and electrically connected to the inner cylinder.

[0013] The impeller assembly includes a driving impeller and discharge impellers arranged in sequence from the front end to the rear end of the rotating shaft; the driving blades of the driving impeller are inclined in the same direction and arranged to cover the entire circumference, and the discharge blades of the discharge impellers are inclined in the same direction and arranged in sequence along the circumference, and the discharge blades together cover the entire circumference; In actual setting, the driving impeller and the discharge impeller are preferably fixed to the rotating shaft by means of set screws, and the driving blades and the discharge blades are preferably inclined in the same direction at an angle of 30°, 45° or 60°; The diameter of the driving impeller is smaller than the diameter of the discharging impeller, and the distance between the driving impeller and the inner cylinder is larger than the discharging distance, and the distance between the discharging impeller and the inner cylinder is smaller than the discharging distance; The air inlet is arranged opposite to the rotation path of the driving blade and deviates from the axis of the rotating shaft.

[0014] Furthermore, a pair of mesh plates covering the gas flow cross-section in the outer tube is provided in the outer tube between the rear end of the inner tube and the gas outlet, the mesh plates are conductive, and a catalyst cavity filled with catalyst is formed between the pair of mesh plates and the outer tube.

[0015] In actual setting, the mesh plate is preferably a perforated metal mesh plate, on which circular small holes are densely distributed at equal intervals; the material selection of the mesh plate should not only ensure its conductivity, but also ensure that it has good high temperature resistance.

[0016] Furthermore, the impeller assembly includes one driving impeller and four discharging impellers, and the outer cylinder, the inner cylinder, the rotating shaft, the driving impeller and the discharging impellers are coaxially arranged, and the discharging impellers are arranged at equal angular intervals in the circumferential direction; The driving blades of the driving impeller are evenly distributed along the circumferential direction, and the discharge blades of the discharge impellers are evenly distributed throughout the circumference.

[0017] Furthermore, the inner wall of the inner cylinder is provided with an inner cylinder internal thread throughout its length, and the rotation direction of each of the driving blades of the driving impeller and each of the discharge blades of the discharge impeller that are inclined in the same direction is the same as the rotation direction of the inner cylinder internal thread.

[0018] In actual configuration, the inner thread of the inner cylinder is preferably triangular or trapezoidal, and the pitch is preferably one third of the axial height of the discharge blade.

[0019] Furthermore, a through mounting hole is provided on the front end surface of the outer cylinder coaxially with the rotating shaft, and a conical screw hole is provided on the front end surface of the rotating shaft; It also includes a clamping structure, which is made of a conductive material, and the positive electrode of the plasma high-voltage power supply is electrically connected to the rotating shaft through the clamping structure; The clamping structure includes a spring seat, a spring, a ball stud and a conical screw; The conical screw is threadably connected with the rotating shaft at the conical screw hole, and a concave conical groove is provided at the front end thereof; The spring seat is fixedly mounted on the front end surface of the outer cylinder, and a spring cavity is provided on one end thereof facing the mounting hole; the front end of the spring is fixedly mounted in the spring cavity, and the rear end thereof is telescopic along the axis of the mounting hole; the front end of the ball pin is fixedly connected to the rear end of the spring, and the rear end is spherical and is pressed tightly in the conical groove under the elastic force of the spring.

[0020] In actual settings, the plasma high-voltage power supply is preferably electrically connected to the spring seat via a high-voltage wire, a wiring port is provided at the connection between the high-voltage wire and the spring seat, and the high-voltage wire is preferably fixed at the wiring port with a set screw; the spring is preferably a round wire spring.

[0021] Further, it also includes an insulating sleeve; The insulating sleeve is located outside the outer cylinder, and the insulating sleeve is arranged outside the spring seat of the compression structure.

[0022] In actual setting, the insulating sleeve is preferably a nylon insulating sleeve.

[0023] Furthermore, the front end and the rear end of the outer cylinder are respectively fixedly mounted with a front end cover plate and a rear end cover plate as the front end face and the rear end face thereof; Gaskets are provided between the front end cover plate and the front end of the outer tube, between the rear end cover plate and the rear end of the outer tube, and between the spring seat and the front end cover plate.

[0024] In actual setting, the gasket arranged between the front end cover plate and the front end of the outer tube and between the spring seat and the front end cover plate is preferably a graphite gasket, and the gasket arranged between the rear end cover plate and the rear end of the outer tube is preferably a graphite or graphite stainless steel composite gasket.

[0025] Furthermore, the air inlet and the air outlet are respectively opened on the front cover plate and the rear cover plate, and the front cover plate and the rear cover plate are respectively provided with an inlet joint and an outlet joint at the air inlet and the air outlet through threaded connection.

[0026] Furthermore, it also includes a bearing structure, and the rotating shaft is rotatably mounted and connected to the front end surface of the outer cylinder through the bearing structure; The bearing structure comprises a bearing seat, a first bearing, a second bearing, an inner sleeve, an outer sleeve and a bearing end cover; The bearing seat is installed and fixed on the front end surface of the outer cylinder in the outer cylinder, and a through bearing seat hole is provided on the bearing seat hole coaxially with the rotating shaft; the first bearing and the second bearing are arranged in the bearing seat hole in sequence from front to back, and the inner sleeve and the outer sleeve are sandwiched between the first bearing and the second bearing; The bearing end cover is inserted into the bearing seat hole from the rear end of the bearing seat hole, pressed forward against the outer ring of the second bearing, and the front end surface of the outer ring of the first bearing is pressed against the step structure at the front end of the bearing seat hole through the outer sleeve; The inner ring of the first bearing, the inner sleeve and the inner ring of the second bearing are sleeved on the front end of the rotating shaft, and the rear end face of the conical screw head is pressed backward against the front end face of the inner ring of the first bearing, and the rear end face of the inner end of the second bearing is pressed against the step structure provided on the rotating shaft through the inner sleeve.

[0027] Further, it also includes an inner tube sleeve; An inner tube sleeve is also provided between the front end of the inner tube and the front end surface of the outer tube, the front end of the inner tube sleeve is pressed against the front end surface of the outer tube, the rear end is pressed against the front end of the inner tube, and the rear end of the inner tube is pressed against the step structure provided in the outer tube.

[0028] The present invention provides a plasma-assisted ammonia catalytic cracking device, which has the following beneficial effects: 1. The present invention utilizes high-voltage discharge to crack and heat ammonia, and utilizes the heat generated by the discharge to heat the catalyst, and utilizes the catalytic action of the catalyst to promote the secondary thermal cracking of ammonia, efficiently cracking ammonia into an ammonia-hydrogen mixed gas for subsequent proportioning or purification, thereby solving the problem of the difficulty in using ammonia as a fuel.

[0029] 2. The discharge channel formed by the discharge impeller of the present invention slides along the thread in the inner cylinder under the joint action of the discharge impeller and the rotating airflow to form a sliding arc. The discharge blades of each discharge impeller are arranged in sequence along the circumferential direction to avoid the arc always staying at a fixed position on the inner wall of the inner cylinder, reduce the concentration of electrode ablation, and effectively extend the service life of the ammonia catalytic cracking device.

[0030] 3. The present invention utilizes ammonia gas flow as the power for the rotation of the rotating shaft and the impeller group, and utilizes the heat generated by discharge as the heat source for thermal cracking. No additional driving mechanism and heating device are required. The structure is simple, compact, easy to disassemble and assemble, and convenient to use and maintain. It is also beneficial to the control of manufacturing cost and occupied space.

[0031] 4. The present invention is applicable to the synthesis of ammonia obtained by producing hydrogen from renewable energy, is beneficial to the large-scale consumption of renewable energy such as solar energy and wind energy, and is environmentally friendly. BRIEF DESCRIPTION OF THE DRAWINGS

[0032] Figure 1 It is a cross-sectional structural schematic diagram of the present invention; Figure 2 It is a partial enlarged structural diagram of A of the present invention; Figure 3 It is a schematic diagram of the cross-sectional structure at DD of the present invention.

[0033] In the figure: 1. Outer cylinder, 11. Air inlet, 12. Air outlet, 13. Screen, 14. Catalyst chamber, 15. Mounting hole; 2. Impeller assembly, 21. Driving impeller, 22. Discharging impeller; 3. Clamping structure, 31. Spring seat, 32. Spring, 33. Ball pin, 34. Conical screw; 4. Insulating sleeve; 5. Rotating shaft; 6. Inner cylinder; 7. Bearing structure, 71. Bearing seat, 72. First bearing, 73. Second bearing, 74. Inner sleeve, 75. Outer sleeve, 76. Bearing end cover; 8. Inner cylinder sleeve; 9. Gasket. DETAILED DESCRIPTION

[0034] In order to make the purpose, technical solution and advantages of the embodiments of the present invention clearer, the technical solution in the embodiments of the present invention will be clearly and completely described below in combination with the embodiments of the present invention. Obviously, the described embodiments are part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0035] like Figure 1~Figure 3 As shown, an ammonia catalytic cracking device based on plasma assistance has the following structural relationship: an outer cylinder 1 is used as a reaction container, and its front end and rear end are respectively blocked by a front end cover plate and a rear end cover plate that are installed and fixed, and the front end cover plate is made of polyetheretherester PEEK material; an air inlet 11 is opened on the front end cover plate, and an inlet joint is threadedly connected to the air inlet 11, and an air outlet 12 is opened on the rear end cover plate, and an outlet joint is threadedly connected to the air outlet 12.

[0036] The inner tube 6 is inserted into the outer tube 1, and a trapezoidal internal thread is arranged inside the inner tube 6; an inner tube sleeve 8 is tightly arranged between the front end of the inner tube 6 and the front end cover plate, and the rear end is tightly arranged against the step structure arranged in the outer tube 1; a pair of mesh plates 13 are arranged between the inner tube 6 and the rear end cover plate to cover the gas flow section in the outer tube 1, and a catalyst cavity 14 filled with catalyst is formed between the pair of mesh plates 13 and the outer tube 1, and the catalyst cavity 14 is filled with catalyst.

[0037] The mesh plate 13 is a perforated mesh plate, which is made of a metal having electrical conductivity and high heat resistance. Small circular holes are densely distributed at equal intervals, with a hole diameter of 1 mm and a hole spacing of 2 mm. The catalyst particles have a diameter of 1 mm to 4 mm.

[0038] The rotating shaft 5 is coaxially arranged with the outer cylinder 1 and the inner cylinder 6, and its front end is rotatably mounted on the front cover plate through the bearing structure 7. The bearing seat 71 is fixed on the rear end surface of the front cover plate, and a through bearing seat hole is provided on the bearing seat hole coaxially with the rotating shaft 5; the first bearing 72 and the second bearing 73 are arranged in the bearing seat hole from front to back, and the inner sleeve 74 and the outer sleeve 75 are sandwiched between the first bearing 72 and the second bearing 73; the bearing end cover 76 is inserted into the bearing seat hole from the rear end of the bearing seat hole, and is pressed against the outer ring of the second bearing 73 forward, and the front end surface of the outer ring of the first bearing 72 is pressed against the step structure at the front end of the bearing seat hole through the outer sleeve 75; the inner ring of the first bearing 72, the inner sleeve 74 and the inner ring of the second bearing 73 are sleeved on the front end of the rotating shaft 5, and the rear end surface of the head of the conical screw 34 is pressed against the front end surface of the inner ring of the first bearing 73 backward, and the rear end surface of the inner end of the second bearing 73 is pressed against the step structure set on the rotating shaft 5 through the inner sleeve 74.

[0039] An impeller group is fixedly mounted on the rotating shaft 5, and the impeller group 2 includes a driving impeller 21 and four discharge impellers 22, namely, a discharge impeller 22a, a discharge impeller 22b, a discharge impeller 22c and a discharge impeller 22d; the driving impeller 21 and the four discharge impellers 22 are respectively fixedly mounted on the rotating shaft 5 by set screws; wherein, the driving impeller 21 is evenly provided with six driving blades at an angular interval of 60°, and the discharge impeller 22 is provided with two discharge blades at an angular interval of 45°, and at the same time, the four discharge impellers 22 are sequentially mounted and fixed on the rotating shaft 5 at an angular interval of 90°. Under this arrangement, each discharge blade and the discharge blade on another adjacent discharge impeller 22 are also arranged at an angular interval of 45°, and the eight discharge blades just cover the entire circumference of 360°.

[0040] The driving blade and the discharge blade are arranged in the same tilted posture, and the angle of the same tilt is 45°. At the same time, the rotation direction of the driving blade and the discharge blade is the same as the rotation direction of the internal thread of the inner cylinder 6. The pitch of the internal thread of the inner cylinder 6 is 3mm, and it is one third of the axial height of the discharge blade. In addition, it should be ensured that the air inlet 11 is arranged directly opposite to the rotation path from the middle to the outer end of the driving blade, and deviates from the axis of the rotating shaft 5.

[0041] The positive electrode of the plasma high voltage power supply is electrically connected to the rotating shaft 5 and the impeller group 2 through the compression structure, and the negative electrode is electrically connected to the inner cylinder 6; the outer cylinder 1 is grounded and electrically connected to the inner cylinder 6. The diameter of the driving impeller 21 is smaller than the diameter of the discharge impeller 22, and the distance between the driving impeller 21 and the inner cylinder 6 is larger than the discharge distance, and the distance between the discharge impeller 22 and the inner cylinder 6 is smaller than the discharge distance.

[0042] The front cover plate and the rotating shaft 5 are coaxially provided with a through mounting hole 15, and the front end surface of the rotating shaft 5 is provided with a conical screw hole; in the clamping structure 3, the conical screw 34 is threadedly connected with the rotating shaft 5 at the conical screw hole, and a concave conical groove is provided at its front end; the spring seat 31 is fixedly installed with the front end surface of the outer cylinder 1, and a spring cavity is provided at one end thereof facing the mounting hole 15; the front end of the spring 32 is fixedly installed in the spring cavity, and the rear end is telescopic along the axis of the mounting hole 15; the front end of the ball pin 33 is connected and fixedly connected with the rear end of the spring 32, and the rear end is spherical and is pressed in the conical groove under the elastic force of the spring 32; the positive electrode of the plasma high-voltage power supply is electrically connected with the spring seat 31 by a high-voltage wire, and a wiring port is provided at the connection point, and the high-voltage wire is fixed at the wiring port by a set screw. The part of the spring seat 31 exposed outside the outer cylinder 1 is completely insulated and covered with an insulating sleeve 5 made of nylon.

[0043] A gasket 9 made of graphite is arranged between the front end cover plate and the front end of the outer tube 1 and between the spring seat 31 and the front end cover plate, and a gasket 9 made of graphite or stainless steel is arranged between the rear end cover plate and the rear end of the outer tube 1 .

[0044] The outer cylinder 1, the rear end cover plate, the impeller assembly 2, the clamping structure 3, the rotating shaft 5, the inner cylinder 6, the bearing structure 7, the inner cylinder sleeve 8, the mesh plate 13, the inlet joint, the outlet joint and the set screws are all made of stainless steel, specifically SUS304, SUS316 or SUS310s stainless steel.

[0045] The above-mentioned ammonia catalytic cracking device is used to carry out catalytic cracking of ammonia gas with a pressure range of 0.1-1.0 MPa, including the following process: The first step is to pass the high-voltage wire through the wire hole on the insulating sleeve 4, connect the wire end to the wiring port of the spring seat 31, and fix it with a set screw; Then, the portion of the spring seat 31 exposed outside the outer tube 1 is completely insulated and covered with an insulating sleeve 4, and the insulating sleeve 4 is installed and fixed to the front end cover plate. The second step is to connect the ammonia catalytic cracking unit to the ammonia supply system through the inlet connector and the outlet connector.

[0046] The third step is to purge the entire ammonia supply system with nitrogen.

[0047] The fourth step is to start the ammonia supply system and then start the plasma high voltage power supply.

[0048] Ammonia enters the outer cylinder 1 from the air inlet 11, acts on the driving blades, and drives the rotating shaft 5 and the discharge impellers 22 fixed on the rotating shaft 5 to rotate synchronously through the driving impeller 21; while the discharge impeller 22 rotates, it discharges the internal thread of the inner cylinder 6, and the discharge channel slides along the internal thread of the inner cylinder 6 under the combined action of the rotation action and the ammonia gas flow, forming a sliding arc, heating and cracking the ammonia in the inner cylinder 6; The heat energy generated by the discharge also heats the catalyst in the catalyst chamber 14 at the same time. The ammonia gas heated and cracked in the inner tube 6 then flows into the catalyst chamber 14 and is cracked by secondary catalytic heat to form an ammonia-hydrogen mixed gas.

[0049] In the fifth step, the ammonia-hydrogen mixed gas flows out of the ammonia catalytic cracking device from the gas outlet 12, and is introduced into the engine system after being tested and mixed / purified as required.

[0050] It should be noted that, in this article, relational terms such as first and second, etc. are only used to distinguish one entity or operation from another entity or operation, and do not necessarily require or imply any such actual relationship or order between these entities or operations. Moreover, the terms "include", "comprise" or any other variants thereof are intended to cover non-exclusive inclusion, so that a process, method, article or device including a series of elements includes not only those elements, but also other elements not explicitly listed, or also includes elements inherent to such process, method, article or device. In the absence of further restrictions, the elements defined by the sentence "comprise a ..." do not exclude the existence of other identical elements in the process, method, article or device including the elements.

[0051] The above embodiments are only used to illustrate the technical solutions of the present invention, rather than to limit the same. Although the present invention has been described in detail with reference to the aforementioned embodiments, those skilled in the art should understand that the technical solutions described in the aforementioned embodiments may still be modified, or some of the technical features may be replaced by equivalents. However, these modifications or replacements do not deviate the essence of the corresponding technical solutions from the spirit and scope of the technical solutions of the embodiments of the present invention.

Claims

1. A plasma-assisted ammonia catalytic cracking device, wherein an outer cylinder (1) is used as a reaction container and is provided with an air inlet (11) and an air outlet (12), and is characterized in that: It comprises a plasma high-voltage power supply, an inner cylinder (6), a rotating shaft (5) and an impeller assembly (2), wherein the front end surface of the outer cylinder (1) is insulated; The inner cylinder (6) is inserted into the outer cylinder (1), and its front end and rear end are respectively connected to the air inlet (11) and the air outlet (12); the rotating shaft (5) is located in the outer cylinder (1) and the inner cylinder (6), and its front end is rotatably mounted and connected to the front end surface of the outer cylinder (1), and an impeller assembly (2) is fixedly mounted on the rotating shaft in the inner cylinder (6); The positive electrode of the plasma high-voltage power supply is electrically connected to the rotating shaft (5) and the impeller assembly (2), and the negative electrode is electrically connected to the inner cylinder (6); the outer cylinder (1) is grounded and electrically connected to the inner cylinder (6); The impeller assembly (2) comprises a driving impeller (21) and discharge impellers (22) which are arranged in sequence from the front end to the rear end of the rotating shaft (5); the driving blades of the driving impeller (21) are inclined in the same direction and are arranged to cover the entire circumference, and the discharge blades of the discharge impellers (22) are inclined in the same direction and are arranged in sequence in the circumference, and the discharge blades together cover the entire circumference; The diameter of the driving impeller (21) is smaller than the diameter of the discharging impeller (22), and the distance between the driving impeller (21) and the inner cylinder (6) is larger than the discharging distance, and the distance between the discharging impeller (22) and the inner cylinder (6) is smaller than the discharging distance; The air inlet (11) is arranged opposite to the rotation path of the driving blade and deviates from the axis of the rotating shaft (5).

2. The plasma-assisted ammonia catalytic cracking device according to claim 1, characterized in that: A pair of mesh plates (13) covering the gas flow cross section in the outer cylinder (1) are provided in the outer cylinder (1) between the rear end of the inner cylinder (6) and the gas outlet (12); the mesh plates (13) are conductive, and a catalyst cavity (14) filled with a catalyst is formed between the pair of mesh plates (13) and the outer cylinder (1).

3. The plasma-assisted ammonia catalytic cracking device according to claim 1 or 2, characterized in that: The impeller assembly (2) comprises one driving impeller (21) and four discharging impellers (22), and the outer cylinder (1), the inner cylinder (6), the rotating shaft (5), the driving impeller (21) and the discharging impellers (22) are coaxially arranged, and the discharging impellers (22) are arranged at equal angular intervals in the circumferential direction; The driving blades of the driving impeller (21) are evenly distributed along the circumferential direction, and the discharge blades of the discharge impellers (22) are evenly distributed throughout the circumference.

4. The plasma-assisted ammonia catalytic cracking device according to claim 1 or 2, characterized in that: The inner wall of the inner cylinder (6) is provided with an inner cylinder internal thread throughout its length, and the rotation direction of each of the driving blades of the driving impeller (21) and each of the discharge blades of the discharge impeller (22) that are inclined in the same direction is the same as the rotation direction of the inner cylinder internal thread.

5. The plasma-assisted ammonia catalytic cracking device according to claim 2, characterized in that: The front end surface of the outer cylinder (1) is provided with a through mounting hole (15) coaxially with the rotating shaft (5), and the front end surface of the rotating shaft (5) is provided with a conical screw hole; It also includes a clamping structure (3), the clamping structure (3) is made of a conductive material, and the positive electrode of the plasma high-voltage power supply is electrically connected to the rotating shaft (5) through the clamping structure (3); The clamping structure (3) comprises a spring seat (31), a spring (32), a ball pin (33) and a conical screw (34); The conical screw (34) is threadably connected to the rotating shaft (5) at the conical screw hole, and a concave conical groove is provided at the front end thereof; The spring seat (31) is fixedly mounted on the front end surface of the outer cylinder (1), and has a spring cavity at one end thereof facing the mounting hole (15); the front end of the spring (32) is fixedly mounted in the spring cavity, and the rear end thereof is telescopic along the axis of the mounting hole (15); the front end of the ball pin (33) is fixedly connected to the rear end of the spring (32), and the rear end is spherical and is pressed tightly into the conical groove under the elastic force of the spring (32).

6. The plasma-assisted ammonia catalytic cracking device according to claim 5, characterized in that: Also includes an insulating sleeve (5); The insulating sleeve (5) is located outside the outer cylinder (1), and the insulating sleeve is arranged outside the compression structure spring seat (31).

7. The plasma-assisted ammonia catalytic cracking device according to claim 5, characterized in that: The front end and rear end of the outer cylinder (1) are respectively fixedly mounted with a front end cover plate and a rear end cover plate as the front end surface and the rear end surface thereof; Gaskets (9) are provided between the front end cover plate and the front end of the outer cylinder (1), between the rear end cover plate and the rear end of the outer cylinder (1), and between the spring seat (31) and the front end cover plate.

8. The plasma-assisted ammonia catalytic cracking device according to claim 7, characterized in that: The air inlet (11) and the air outlet (12) are respectively provided on the front cover plate and the rear cover plate, and the front cover plate and the rear cover plate are respectively provided with an inlet joint and an outlet joint at the air inlet (11) and the air outlet (12) via threads.

9. The plasma-assisted ammonia catalytic cracking device according to claim 5, characterized in that: It also includes a bearing structure (7), through which the rotating shaft (5) is rotatably mounted and connected to the front end surface of the outer cylinder (1); The bearing structure (7) comprises a bearing seat (71), a first bearing (72), a second bearing (73), an inner sleeve (74), an outer sleeve (75) and a bearing end cover (76); The bearing seat (71) is fixedly mounted on the front end surface of the outer cylinder (1) in the outer cylinder (1), and a bearing seat hole is provided thereon coaxially with the rotating shaft (5); the first bearing (72) and the second bearing (73) are arranged in the bearing seat hole in sequence from front to back, and the inner sleeve (74) and the outer sleeve (75) are sandwiched between the first bearing (72) and the second bearing (73); The bearing end cover (76) is inserted into the bearing seat hole from the rear end of the bearing seat hole, pressed forward against the outer ring of the second bearing (73), and the front end surface of the outer ring of the first bearing (72) is pressed against the step structure at the front end of the bearing seat hole through the outer sleeve (75); The inner ring of the first bearing (72), the inner sleeve (74) and the inner ring of the second bearing (73) are sleeved onto the front end of the rotating shaft (5); the rear end surface of the head of the conical screw (34) is pressed backward against the front end surface of the inner ring of the first bearing (73); and the rear end surface of the inner end of the second bearing (73) is pressed against the step structure provided on the rotating shaft (5) via the inner sleeve (74).

10. The plasma-assisted ammonia catalytic cracking device according to claim 5, characterized in that: Also includes an inner tube sleeve (8); An inner tube sleeve (8) is further provided between the front end of the inner tube (6) and the front end surface of the outer tube (1); the front end of the inner tube sleeve (8) is pressed against the front end surface of the outer tube (1), and the rear end is pressed against the front end of the inner tube (6), so that the rear end of the inner tube (6) is pressed against a step structure provided in the outer tube (1).

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