A nitrogen-oxygen compound rare earth ceramic riser base and a preparation process thereof

Abstract

The application discloses a nitrogen-oxygen composite rare earth ceramic riser base and a preparation process thereof, and relates to the technical field of coke oven riser. The riser base comprises a base and a riser cylinder, the riser cylinder is fixedly arranged on the upper portion of the base, and the riser cylinder and the base are both circular in cross section and concentrically arranged. The base comprises the following components in parts by weight: 40-50 parts by weight of silicon carbide powder, 12-13 parts by weight of industrial silicon powder, 8-10 parts by weight of silicon micro powder, 2-3 parts by weight of additives and 33-36 parts by weight of a binding agent. A decoking assembly for cleaning graphite and tar attached to the inner wall of the base is arranged in the base. The preparation process comprises the following steps: S1, mixing; S2, forming; S3, sintering; and S4, installation. The application selects high-purity silicon carbide as the main raw material, guarantees excellent thermal shock stability of the product, adds rare earth oxides to improve the toughness of the riser base material, and further improves the wear resistance and oxidation resistance of the riser base.

Description

Technical Field

[0001] This invention relates to the field of coke oven riser technology, specifically to a nitrogen-oxygen composite rare earth ceramic riser base and its preparation process. Background Technology

[0002] The base of the coke oven riser is installed at the bottom of the riser pipe, which is a channel connecting the coke oven and the gas collecting pipe. The riser pipe opening at the top of the coke oven is used to exhaust the raw coal gas in the carbonization chamber.

[0003] During the operation of a coke oven, tar vapors in the generated raw coal gas are cooled or condensed and precipitated, flowing down the walls of the riser pipe to the bottom. When the precipitated liquid tar encounters the high-temperature environment inside the pipe, it undergoes pyrolysis and thermal condensation reactions to generate graphite. The higher the temperature, the greater the amount of graphite deposited inside the riser pipe, adhering to the inner wall, especially at the base, thus affecting the riser pipe's performance. Therefore, it is necessary to optimize the material of the riser pipe base to reduce graphite adhesion, and simultaneously employ appropriate coke cleaning methods to achieve optimal protection.

[0004] Patent CN113150802B discloses an online coking cleaning riser pipe for coke ovens and its online coking cleaning method. The invention includes a coke oven body, a riser pipe seat, a riser pipe, a riser pipe tee, an online coking cleaning drive device, an internal connecting section, a riser pipe water seal cover, a heat exchanger inside the riser pipe, a coking cleaning drive screw, a coking cleaning device, a support, a pipe seat coking cleaning device, and a coke oven mouth coking cleaning device. The riser pipe seat is installed at the oven mouth of the coke oven body, and the riser pipe is installed on the riser pipe seat. A riser pipe tee is installed on one side of the top of the riser pipe, and a riser pipe water seal cover is fixed to the top of the riser pipe. This invention addresses the issue of coking at the oven mouth of the riser pipe seat and at the root channel of the riser pipe during coke oven operation, thus achieving online coking cleaning of the coke oven riser pipe and solving the coking problem inherent in the online coking cleaning device itself. However, most of the device structure is located inside the riser pipe, making it prone to focusing, and no optimization is made to the material and structure of the riser pipe seat. Summary of the Invention

[0005] To address the aforementioned problems, this invention provides...

[0006] The technical solution of this invention is:

[0007] A nitrogen-oxygen composite rare earth ceramic riser base includes a base and a riser cylinder. The riser cylinder is fixedly disposed on the upper part of the base. The cross-sections of the riser cylinder and the base are both circular and concentrically arranged.

[0008] The components of the base, by weight, include: 40-50 parts by weight of silicon carbide powder, 12-13 parts by weight of industrial silicon powder, 8-10 parts by weight of silicon micro powder, 2-3 parts by weight of additives, and 33-36 parts by weight of binder.

[0009] The base is equipped with a descaling component for cleaning graphite and tar adhering to the inner wall of the base.

[0010] Further, the silicon carbide powder contains, by mass percentage: 0.2-0.3% Fe₂O₃, with the balance being SiC; the industrial silicon powder contains, by mass percentage: 0.5-0.55% Fe, 0.2-0.4% Al, 0.01-0.02% Ca, with the balance being Si; and the silicon micropowder contains, by mass percentage: 96-99% SiO₂.

[0011] Note: By optimizing the composition of the base, excellent thermal shock stability of the riser pipe base product is ensured.

[0012] Furthermore, the additive is one or more of rare earth oxides La2O3, Nd2O3, and CeO2, and the binder is a CMC solution with a mass concentration of 40%.

[0013] Note: By adding rare earth oxides during the production process, the toughness of the riser base material is improved, further enhancing the product's wear resistance and oxidation resistance.

[0014] Furthermore, the coke removal assembly includes a first fixing rod, a second fixing rod, a rotating shaft assembly, and a coke removal rod. The first fixing rod and the second fixing rod are both fixedly installed on one side of the inner wall of the riser tube and extend through the other side of the riser tube. The first fixing rod is located directly above the second fixing rod. Both the first fixing rod and the second fixing rod are hollow. The first fixing rod has a first groove inside, and the second fixing rod has a second groove inside.

[0015] The rotating shaft assembly is located at the center of the base. The rotating shaft assembly includes an upper rotating shaft and a lower rotating shaft that are slidably connected. The upper rotating shaft passes through the middle of the second fixed rod and extends to the bottom of the first fixed rod. A pulley assembly is provided inside the second groove of the second fixed rod. The pulley assembly includes a first pulley and a second pulley that rotate synchronously. The upper rotating shaft is engaged with the center of the second pulley and rotates synchronously with the second pulley. The first pulley is driven to rotate by a pulley motor located below the second fixed rod. The top of the lower rotating shaft is provided with a steel wire rope for pulling it to slide up and down along the inside of the upper rotating shaft. The steel wire rope passes through the bottom of the first fixed rod and the first groove and is connected to a winding drum located at the outer end of the first fixed rod. The bottom of the winding drum is provided with a servo motor for driving it to reciprocate. The servo motor and the pulley motor are fixedly arranged side by side.

[0016] The coke-clearing rods are a plurality of rods arranged at equal intervals around the bottom of the lower rotating shaft. The bottom of the coke-clearing rods is provided with a groove, and the top of the groove is provided with a sliding groove for accommodating a spring. One end of the spring is fixedly connected to the innermost side of the sliding groove, and the other end of the spring is fixedly provided with a slider. The bottom of the slider is provided with a first rotating rod rotatably connected thereto. The bottom of the first rotating rod is fixedly connected to a connecting rod. The bottom of both ends of the connecting rod is provided with a second rotating rod rotatably connected thereto. The bottom of the second rotating rod is fixedly connected to a coke-clearing plate.

[0017] Note: The coke removal component enables continuous coke removal during coke oven operation, preventing the accumulation of tar and graphite on the inner wall of the riser base.

[0018] Furthermore, the upper rotating shaft has limiting grooves on both sides of its inner wall, which are slidably connected to limiting protrusions on the outer wall of the lower rotating shaft to enable the upper and lower rotating shafts to slide and rotate synchronously. The second fixing rod has a limiting slot on each side corresponding to the second pulley for vertically fixing the second pulley. A row of pulleys is provided at the bottom of the limiting slot to support the surface of the second pulley.

[0019] Explanation: The combination of the limiting groove and the limiting protrusion enables the upper and lower rotating shafts to slide relative to each other and rotate synchronously.

[0020] Furthermore, there are three coke-clearing rods, and the coke-clearing plate is arranged in a triangular shape. Each corner of the coke-clearing plate is provided with an arc-shaped scraper. An air guide pipe is provided on one side of the end of the first fixed rod. The air guide pipe is connected to an externally installed air pump and communicates with the inside of the first groove. The bottom of the first fixed rod is provided with a rotating groove for rotating and sealingly connecting with the upper rotating shaft. The top of the lower rotating shaft is provided with an opening for air intake. The opening extends to the bottom of the lower rotating shaft and communicates with the air outlet provided at the bottom of the coke-clearing rod. The end of the air outlet extends out from the inner wall of the groove.

[0021] Explanation: By injecting air into the inner wall of the riser base using an air pump, the accumulation of tar and graphite on the coke cleaning component body can be reduced, especially in areas prone to accumulation such as springs. This extends the service life of the coke cleaning component, while ensuring smooth internal circulation within the riser base, reducing the pressure in the subsequent carbonization chamber, preventing smoke from the furnace door and frame, and making it more energy-efficient and environmentally friendly. The scraper design also prevents damage to the internal lining bricks during the rise and rotation of the coke cleaning component.

[0022] The manufacturing process of a nitrogen-oxygen composite rare earth ceramic riser base as described in any of the above-mentioned methods includes the following steps:

[0023] S1. Mixing: Weigh the silicon carbide powder, industrial silicon powder and silicon micro powder according to the weight parts and grind them for later use. Put the silicon carbide powder and binder into a mixer and mix for 10-15 minutes. Then add the industrial silicon powder, silicon micro powder and additives, continue to mix for 15-20 minutes and then discharge the material. After re-mixing for 36 hours, the mixture is obtained.

[0024] S2. Molding: The mixture obtained in step S1 is placed in a vibratory press for molding. The molding time is 9-10 hours. After demolding, it is naturally dried for 24 hours, and then placed at 200℃ for 48 hours to obtain precast bricks.

[0025] S3. Sintering: The precast bricks obtained in step S2 are placed in a sintering furnace for sintering. During sintering, N2 is introduced to maintain a slightly positive pressure of 0.1 MPa inside the furnace. First, the temperature is raised to 1000-1050℃ at a heating rate of 15-20℃ / min and held for 36 hours. Then, the temperature is raised to 1400-1420℃ at a heating rate of 4-6℃ / min and held for 36 hours to obtain the sintered base.

[0026] S4. Installation: Install the riser tube cylinder on the upper part of the base obtained in step S3, and install the descaling component inside the base to obtain the nitrogen-oxygen composite rare earth ceramic riser tube base.

[0027] Furthermore, in step S1, the maximum particle size of the silicon carbide powder, industrial silicon powder, and silicon micro powder grinding does not exceed 3.5 mm.

[0028] Note: Stability of the mixing process is ensured by controlling the maximum particle size of silicon carbide powder, industrial silicon powder, and silicon micro powder during grinding.

[0029] Furthermore, the brick shape formed in step S2 is 230mm long, 114mm wide, and 65mm high.

[0030] Note: By controlling the dimensions of the brick shape, it is easier to form the riser base.

[0031] The beneficial effects of this invention are:

[0032] (1) The nitrogen-oxygen composite rare earth ceramic riser base of the present invention optimizes the raw material formula, strictly controls the purity of the raw materials, selects high-purity silicon carbide as the main raw material to ensure the excellent thermal shock stability of the product, and adds rare earth oxides to improve the toughness of the riser base material, further improving the wear resistance and oxidation resistance of the riser base.

[0033] (2) The nitrogen-oxygen composite rare earth ceramic riser base of the present invention can continuously perform coking treatment while the coke oven is in use by the provided coking cleaning component, which prevents tar and graphite from accumulating on the inner wall of the riser base; by setting an air pump to inject air into the inner wall of the riser base, the accumulation of tar and graphite on the body of the coking cleaning component can be reduced, especially in parts that are prone to accumulation such as springs, which extends the service life of the coking cleaning component, while ensuring smooth internal circulation of the riser base, reducing the pressure of the subsequent carbonization chamber, avoiding smoke from the furnace door and furnace frame, and making it more energy-saving and environmentally friendly. The scraper can prevent damage to the internal lining bricks when the coking cleaning component rises and rotates.

[0034] (3) The nitrogen-oxygen composite rare earth ceramic riser base preparation process of the present invention uses silicon carbide powder, industrial silicon powder and silicon micro powder to synthesize silicon nitride or silon bond phase with high-purity nitrogen gas, which greatly improves the strength and wear resistance of the riser base, while increasing the N2 pressure, making the N element penetration layer in the material product thicker, and ensuring the integrity and uniformity of the riser base. Attached Figure Description

[0035] Figure 1 This is a schematic diagram of the overall structure of the nitrogen-oxygen composite rare earth ceramic riser base of the present invention;

[0036] Figure 2 This is a schematic diagram of the bottom structure of the nitrogen-oxygen composite rare earth ceramic riser pipe base of the present invention;

[0037] Figure 3 This is a top view of the nitrogen-oxygen composite rare earth ceramic riser base of the present invention.

[0038] Figure 4 This is a front view and internal structural schematic diagram of the descaling component of the nitrogen-oxygen composite rare earth ceramic riser tube base of the present invention.

[0039] Figure 5 This is a schematic diagram of the bottom structure of the descaling rod of the nitrogen-oxygen composite rare earth ceramic riser tube base of the present invention.

[0040] Figure 6 This is a schematic diagram of the internal pulley assembly structure of the second fixing rod of the nitrogen-oxygen composite rare earth ceramic riser pipe base of the present invention;

[0041] Figure 7 This is a schematic diagram of the internal limiting groove structure of the second fixing rod of the nitrogen-oxygen composite rare earth ceramic riser pipe base of the present invention;

[0042] Figure 8 This is a schematic diagram of the connection structure between the upper and lower rotating shafts of the nitrogen-oxygen composite rare earth ceramic riser pipe base of the present invention.

[0043] Figure 9 This is a schematic diagram of the rotating groove structure in the middle of the first fixing rod of the nitrogen-oxygen composite rare earth ceramic riser pipe base of the present invention.

[0044] Figure 10 This is a process flow diagram of the preparation process of the nitrogen-oxygen composite rare earth ceramic riser base of the present invention.

[0045] Among them, 1-base, 2-riser tube cylinder, 3-first fixed rod, 31-first groove, 32-winding drum, 33-servo motor, 34-air guide pipe, 35-air pump, 36-rotating groove, 4-second fixed rod, 41-second groove, 5-rotating shaft assembly, 51-upper rotating shaft, 52-lower rotating shaft, 53-wire rope, 54-limiting groove, 55-limiting protrusion, 56-opening, 6-coke clearing rod, 61-groove, 62-sliding groove, 63-spring, 64-slider, 65-first rotating rod, 66-connecting rod, 67-second rotating rod, 68-coke clearing plate, 69-scraper, 7-pulley assembly, 71-first pulley, 72-second pulley, 73-pulley motor, 8-limiting slot, 81-pulley, 9-air outlet. Detailed Implementation

[0046] Example 1

[0047] like Figure 1 As shown, a nitrogen-oxygen composite rare earth ceramic riser base includes a base 1 and a riser cylinder 2. The riser cylinder 2 is fixedly installed on the upper part of the base 1. The cross-sections of the riser cylinder 2 and the base 1 are both circular and concentrically arranged.

[0048] The components of the base 1, by weight, include: 45 parts by weight of silicon carbide powder, 12.5 parts by weight of industrial silicon powder, 9 parts by weight of silicon micro powder, 2.5 parts by weight of additives, and 34 parts by weight of binder; the silicon carbide powder, by weight percentage, contains 98.5% SiC and 0.25% Fe2O3; the industrial silicon powder, by weight percentage, contains 98.5% Si, 0.52% Fe, 0.3% Al, and 0.015% Ca; the silicon micro powder, by weight percentage, contains 98% SiO2; the additive is rare earth oxide La2O3, and the binder is a 40% CMC solution;

[0049] The base 1 is equipped with a tar removal component for cleaning the graphite and tar adhering to the inner wall of the base 1. The tar removal component is a commercially available tar removal component.

[0050] Example 2

[0051] The difference between this embodiment and Embodiment 1 is that the composition ratio of the base 1 is different.

[0052] The components of the base 1, by weight, include: 40 parts by weight of silicon carbide powder, 12 parts by weight of industrial silicon powder, 8 parts by weight of silicon micro powder, 2 parts by weight of additives, and 33 parts by weight of binder; the silicon carbide powder, by weight percentage, contains 98% SiC and 0.2% Fe2O3; the industrial silicon powder, by weight percentage, contains 98% Si, 0.5% Fe, 0.2% Al, and 0.01% Ca; the silicon micro powder, by weight percentage, contains 96% SiO2; the additive is rare earth oxide Nd2O3, and the binder is a 40% CMC solution.

[0053] Example 3

[0054] The difference between this embodiment and Embodiment 1 is that the composition ratio of the base 1 is different.

[0055] The components of the base 1, by weight, include: 50 parts by weight of silicon carbide powder, 13 parts by weight of industrial silicon powder, 10 parts by weight of silicon micro powder, 3 parts by weight of additives, and 36 parts by weight of binder; the silicon carbide powder, by weight percentage, contains 99% SiC and 0.3% Fe2O3; the industrial silicon powder, by weight percentage, contains 99% Si, 0.55% Fe, 0.4% Al, and 0.02% Ca; the silicon micro powder, by weight percentage, contains 99% SiO2; the additives are rare earth oxides La2O3, Nd2O3, and CeO2 mixed in a mass ratio of 1:1:1, and the binder is a 40% CMC solution.

[0056] Example 4

[0057] The difference between this embodiment and Embodiment 1 is that:

[0058] like Figures 1-4 As shown, the coke removal assembly includes a first fixing rod 3, a second fixing rod 4, a rotating shaft assembly 5, and a coke removal rod 6. The first fixing rod 3 and the second fixing rod 4 are both fixedly installed on one side of the inner wall of the riser tube 2 and extend through the other side of the riser tube 2. The first fixing rod 3 is located directly above the second fixing rod 4. Both the first fixing rod 3 and the second fixing rod 4 are hollow. The first fixing rod 3 has a first groove 31 inside, and the second fixing rod 4 has a second groove 41 inside.

[0059] like Figure 1 , 2 4, 6 The rotating shaft assembly 5 is located at the center of the base 1. The rotating shaft assembly 5 includes an upper rotating shaft 51 and a lower rotating shaft 52 that are slidably connected. The upper rotating shaft 51 passes through the middle of the second fixed rod 4 and extends to the bottom of the first fixed rod 3. The second groove 41 of the second fixed rod 4 is provided with a pulley assembly 7. The pulley assembly 7 includes a first pulley 71 and a second pulley 72 that rotate synchronously. The upper rotating shaft 51 is engaged with the center of the second pulley 72 and the upper rotating shaft 51 and the second pulley 72 rotate synchronously. The first pulley 71 passes through the position The pulley motor 73 below the second fixed rod 4 drives the rotation. The top of the lower rotating shaft 52 is provided with a steel wire rope 53 for pulling it to slide up and down along the inside of the upper rotating shaft 51. The steel wire rope 53 passes through the bottom of the first fixed rod 3 and the first groove 31 and is connected to the winding drum 32 located at the outer end of the first fixed rod 3. The bottom of the winding drum 32 is provided with a servo motor 33 for driving it to reciprocate. The servo motor 33 and the pulley motor 73 are fixedly arranged side by side. Both the pulley motor 73 and the servo motor 33 are commercially available products.

[0060] like Figures 6-8 As shown, the upper rotating shaft 51 has limiting grooves 54 on both sides of its inner wall. The limiting grooves 54 are slidably connected to the limiting protrusions 55 on the outer wall of the lower rotating shaft 52. This is used to complete the sliding and synchronous rotation of the upper rotating shaft 51 and the lower rotating shaft 52. The second fixing rod 4 has a limiting groove 8 on both sides corresponding to the second pulley 72 for vertically fixing the second pulley 72. A row of pulleys 81 is provided at the bottom of the limiting groove 8 to support the surface of the second pulley 72.

[0061] like Figure 1 , 2As shown in Figures 5 and 9, there are three coke-clearing rods 6, circumferentially spaced at the bottom of the lower rotating shaft 52. Each coke-clearing rod 6 has a slot 61 at its bottom, and a groove 62 at the top of the slot 61 to accommodate a spring 63. One end of the spring 63 is fixedly connected to the innermost side of the groove 62, and the other end of the spring 63 is fixedly connected to a slider 64. The bottom of the slider 64 is provided with a first rotating rod 65 rotatably connected to it. A connecting rod 66 is fixedly connected to the bottom of the first rotating rod 65. Both ends of the connecting rod 66 are provided with second rotating rods 67 rotatably connected to it. A coke-clearing plate 68 is fixedly connected to the bottom of the second rotating rods 67. The coke-clearing process... There are three rods 6. The coke cleaning plate 68 is triangular and has an arc-shaped scraper 69 at each corner. The first fixed rod 3 has an air guide pipe 34 on one side of its end. The air guide pipe 34 is connected to an external air pump 35 and communicates with the inside of the first groove 31. The bottom of the first fixed rod 3 has a rotating groove 36 for rotating and sealingly connecting with the upper rotating shaft 51. The top of the lower rotating shaft 52 has an opening 56 for air intake. The opening 56 extends to the bottom of the lower rotating shaft 52 and communicates with the air outlet 9 at the bottom of the coke cleaning rod 6. The end of the air outlet 9 extends out from the inner wall of the groove 61.

[0062] Working principle: The working principle of the desiccant removal component of the present invention will be briefly explained below.

[0063] In use, the first belt pulley 71 is rotated by turning on the belt pulley motor 73, which in turn drives the second belt pulley 72 to rotate. The second belt pulley 72 is supported and rotated by the pulley 81, thereby driving the upper rotating shaft 51 to rotate synchronously, which in turn drives the lower rotating shaft 52 and the coke cleaning rod 6 to rotate synchronously. During the rotation of the coke cleaning rod 6, the scraper 69 of the coke cleaning plate 68 contacts the inner wall of the base 1 and abuts against the inner wall under the action of friction. At this time, the connecting plate 66 rotates along the slot 61 under the action of the second rotating rod 67 and the first rotating rod 65. The slider 64 compresses the spring 63 until the spring 63 is compressed to its shortest position. At this time, the connecting rod 66 is perpendicular to the inner wall of the base 1, and the spring 63 rebounds. The rotating shaft group continues to rotate so that the other coke cleaning plate 68 located on the same connecting rod 66 contacts the inner wall of the base 1.

[0064] Simultaneously with the above process, the servo motor 33 is turned on to drive the winding drum 32 to rotate back and forth, thereby pulling the lower rotating shaft 52 seat up and down through the wire rope 53. The limiting protrusion 55 of the upper rotating shaft 52 slides relative to each other in the limiting groove 54. At the same time, the coke cleaning plate 68 and the hanging plate 69 also move up and down, thereby cleaning and scraping the inner wall of the base 1.

[0065] During the scraping process, the air pump 35 is turned on to deliver compressed air to the air outlet 9 through the air guide pipe 34, the first groove 31, and the opening 56, thereby reducing the accumulation of tar and graphite on the body of the coking removal component, especially in areas prone to accumulation such as springs, and extending the service life of the coking removal component.

[0066] Example 5

[0067] This embodiment describes the fabrication process of a nitrogen-oxygen composite rare-earth ceramic riser tube base according to Example 1, including the following steps:

[0068] S1. Mixing: Weigh out the silicon carbide powder, industrial silicon powder and silicon micro powder according to the weight parts and grind them for later use. Put the silicon carbide powder and binder into a mixer and mix for 13 minutes. Then add the industrial silicon powder, silicon micro powder and additives, and continue to mix for 17 minutes before discharging. After re-mixing for 36 hours, a mixture is obtained. Re-mixing means that after standing for 12 hours, it is continued to mix for 24 hours. The maximum particle size of the silicon carbide powder, industrial silicon powder and silicon micro powder should not exceed 3.5 mm.

[0069] S2. Molding: The mixture obtained in step S1 is placed in a vibratory press for molding. The molding time is 9.5 hours. After demolding, it is naturally dried for 24 hours, and then dried at 200℃ for 48 hours to obtain precast bricks. The molded bricks are 230 mm long, 114 mm wide, and 65 mm high.

[0070] S3. Sintering: The precast bricks obtained in step S2 are placed in a sintering furnace for sintering. During sintering, N2 is introduced to maintain a slightly positive pressure of 0.1 MPa inside the furnace. First, the temperature is raised to 1025℃ at a heating rate of 18℃ / min and held for 36 hours. Then, the temperature is raised to 1410℃ at a heating rate of 5℃ / min and held for 36 hours to obtain the sintered base 1.

[0071] S4. Installation: Install the riser tube body 2 on the upper part of the base 1 obtained in step S3, and install the coking removal component inside the base 1 to obtain the nitrogen-oxygen composite rare earth ceramic riser tube base.

[0072] Example 6

[0073] The difference between this embodiment and embodiment 5 is that the process parameters of step S1 are different.

[0074] S1. Mixing: Weigh out the silicon carbide powder, industrial silicon powder and silicon micro powder according to the specified weight parts, grind them for later use, put the silicon carbide powder and binder into a mixer and mix for 10 minutes, then add the industrial silicon powder, silicon micro powder and additives, continue mixing for 15 minutes and then discharge the material. After re-mixing for 36 hours, a mixture is obtained. The maximum particle size of the silicon carbide powder, industrial silicon powder and silicon micro powder should not exceed 3.5 mm.

[0075] Example 7

[0076] The difference between this embodiment and embodiment 5 is that the process parameters of step S1 are different.

[0077] S1. Mixing: Weigh out the silicon carbide powder, industrial silicon powder and silicon micro powder according to the specified weight proportions, grind them for later use, put the silicon carbide powder and binder into a mixer and mix for 15 minutes, then add the industrial silicon powder, silicon micro powder and additives, continue mixing for 20 minutes and then discharge the material. After re-mixing for 36 hours, a mixture is obtained. The maximum particle size of the ground silicon carbide powder, industrial silicon powder and silicon micro powder shall not exceed 3.5 mm.

[0078] Example 8

[0079] The difference between this embodiment and embodiment 5 is that the process parameters for steps S2 and S3 are different.

[0080] S2. Molding: The mixture obtained in step S1 is placed in a vibratory press for molding. The molding time is 9 hours. After demolding, it is naturally dried for 24 hours and then placed at 200℃ for 48 hours to obtain precast bricks. The molded bricks are 230mm long, 114mm wide and 65mm high.

[0081] S3. Sintering: The precast bricks obtained in step S2 are placed in a sintering furnace for sintering. During sintering, N2 is introduced to maintain a slightly positive pressure of 0.1 MPa inside the furnace. First, the temperature is raised to 1000℃ at a heating rate of 15℃ / min and held for 36 hours. Then, the temperature is raised to 1400℃ at a heating rate of 4℃ / min and held for 36 hours to obtain the sintered base 1.

[0082] Example 9

[0083] The difference between this embodiment and embodiment 5 is that the process parameters for steps S2 and S3 are different.

[0084] S2. Molding: The mixture obtained in step S1 is placed in a vibratory press for molding. The molding time is 10 hours. After demolding, it is naturally dried for 24 hours and then dried at 200℃ for 48 hours to obtain precast bricks. The molded bricks are 230mm long, 114mm wide and 65mm high.

[0085] S3. Sintering: The precast bricks obtained in step S2 are placed in a sintering furnace for sintering. During sintering, N2 is introduced to maintain a slightly positive pressure of 0.1 MPa inside the furnace. First, the temperature is raised to 1050℃ at a heating rate of 20℃ / min and held for 36 hours. Then, the temperature is raised to 1420℃ at a heating rate of 6℃ / min and held for 36 hours to obtain the sintered base 1.

[0086] Experimental Example

[0087] Taking the nitrogen-oxygen composite rare earth ceramic riser base prepared by the process method in Example 5 as an example, performance testing was conducted. First, the reaction mechanism of the process steps of the present invention is summarized:

[0088] Silicon begins to react in an N2 environment at around 1000℃ to form crystalline Si3N4. At this point, the active Si3N4 microcrystals and active SiO2 form a solid solution, forming stable Si2N2O crystals. The role of rare earth oxide additives is to accelerate the reaction under liquid phase conditions. During sintering, the reactants first dissolve in the liquid phase, then fill the pores through diffusion, and finally Si2N2O precipitates from the liquid phase. The reaction equation is as follows:

[0089] 3Si + 2N₂ → Si₃N₄

[0090] Si3N4 + SiO2 → 2Si2N2O

[0091] 3Si + 2N₂ + SiO₂ → 2Si₂N₂O

[0092] The test results of the obtained nitrogen-oxygen composite rare earth ceramic riser pipe base are as follows:

[0093] SiC: 78.80%, Si2N2O: 18.83%, Porosity: 10.8%, Bulk density: 2.75 g / m³ 3 Pressure resistance at room temperature: 216MPa; flexural strength at room temperature: 46.8MPa; thermal shock resistance: >30 water cooling cycles at 1100℃; oxidation resistance: 1200℃ / 100h +0.012%.

Claims

1. A nitrogen-oxygen composite rare earth ceramic riser pipe base, characterized in that, It includes a base (1) and a riser tube (2), wherein the riser tube (2) is fixedly installed on the upper part of the base (1), and the cross sections of the riser tube (2) and the base (1) are both circular and concentrically arranged; The components of the base (1) by weight include: 40-50 parts by weight of silicon carbide powder, 12-13 parts by weight of industrial silicon powder, 8-10 parts by weight of silicon micro powder, 2-3 parts by weight of additives, and 33-36 parts by weight of binder. The base (1) is equipped with a tar removal assembly for cleaning graphite and tar adhering to the inner wall of the base (1). The tar removal assembly includes a first fixing rod (3), a second fixing rod (4), a rotating shaft assembly (5), and a tar removal rod (6). The first fixing rod (3) and the second fixing rod (4) are both fixedly installed on one side of the inner wall of the riser cylinder (2) and pass through the other side of the riser cylinder (2). The first fixing rod (3) is located directly above the second fixing rod (4). The first fixing rod (3) and the second fixing rod (4) are both hollow. The first fixing rod (3) has a first groove (31) inside, and the second fixing rod (4) has a second groove (41) inside. The rotating shaft assembly (5) is located at the center of the base (1). The rotating shaft assembly (5) includes an upper rotating shaft (51) and a lower rotating shaft (52) that are slidably connected. The upper rotating shaft (51) passes through the middle of the second fixing rod (4) and extends to the bottom of the first fixing rod (3). A pulley assembly (7) is provided inside the second groove (41) of the second fixing rod (4). The pulley assembly (7) includes a first pulley (71) and a second pulley (72) that rotate synchronously. The upper rotating shaft (51) is engaged with the center of the second pulley (72), and the upper rotating shaft (51) and the second pulley (72) rotate synchronously. The first pulley (71) is driven to rotate by a pulley motor (73) located below the second fixed rod (4). The top of the lower rotating shaft (52) is provided with a steel wire rope (53) for pulling it to slide up and down along the inside of the upper rotating shaft (51). The steel wire rope (53) passes through the bottom of the first fixed rod (3) and the first groove (31) and is connected to the winding drum (32) located at the outer end of the first fixed rod (3). The bottom of the winding drum (32) is provided with a servo motor (33) for driving it to reciprocate. The servo motor (33) and the pulley motor (73) are fixedly arranged side by side. The coke-clearing rods (6) are a plurality of rods and are circumferentially spaced at the bottom end of the lower rotating shaft (52). The bottom of the coke-clearing rods (6) is provided with a groove (61), and the top of the groove (61) is provided with a sliding groove (62) for accommodating a spring (63). One end of the spring (63) is fixedly connected to the innermost side of the sliding groove (62), and the other end of the spring (63) is fixedly provided with a slider (64). The bottom of the slider (64) is provided with a first rotating rod (65) rotatably connected thereto. The bottom of the first rotating rod (65) is fixedly connected with a connecting rod (66). The bottom of both ends of the connecting rod (66) is provided with a second rotating rod (67) rotatably connected thereto. The bottom of the second rotating rod (67) is fixedly connected with a coke-clearing plate (68).

2. The nitrogen-oxygen composite rare earth ceramic riser pipe base according to claim 1, characterized in that, The silicon carbide powder contains, by mass percentage: 0.2-0.3% Fe2O3, with the balance being SiC; the industrial silicon powder contains, by mass percentage: 0.5-0.55% Fe, 0.2-0.4% Al, 0.01-0.02% Ca, with the balance being Si; the silicon micropowder contains, by mass percentage: 96-99% SiO2.

3. The nitrogen-oxygen composite rare earth ceramic riser pipe base according to claim 1, characterized in that, The additive is one or more of rare earth oxides La2O3, Nd2O3, and CeO2, and the binder is a CMC solution with a mass concentration of 40%.

4. The nitrogen-oxygen composite rare earth ceramic riser pipe base according to claim 1, characterized in that, The upper rotating shaft (51) has a limiting groove (54) on both sides of its inner wall. The limiting groove (54) is slidably connected to the limiting protrusion (55) on the outer wall of the lower rotating shaft (52) to complete the sliding and synchronous rotation of the upper rotating shaft (51) and the lower rotating shaft (52). The second fixing rod (4) has a limiting slot (8) on both sides corresponding to the second pulley (72) for vertically fixing the second pulley (72). The bottom of the limiting slot (8) has a row of pulleys (81) to support the surface of the second pulley (72).

5. The nitrogen-oxygen composite rare earth ceramic riser pipe base according to claim 1, characterized in that, There are 3 coke-clearing rods (6), and the coke-clearing plate (68) is set in a triangular shape. Each corner of the coke-clearing plate (68) is provided with an arc-shaped scraper (69). The first fixed rod (3) is provided with an air guide pipe (34) on one side of its end. The air guide pipe (34) is connected to an externally provided air pump (35). The air guide pipe (34) is connected to the inside of the first groove (31). The bottom of the first fixed rod (3) is provided with a rotating groove (36) for rotating and sealingly connected with the upper rotating shaft (51). The top of the lower rotating shaft (52) is provided with an opening (56) for air intake. The opening (56) extends to the bottom of the lower rotating shaft (52) and is connected to the air outlet (9) provided at the bottom of the coke-clearing rod (6). The end of the air outlet (9) extends out from the inner wall of the groove (61).

6. The preparation process of a nitrogen-oxygen composite rare earth ceramic riser base according to any one of claims 1 to 5, characterized in that, Includes the following steps: S1. Mixing: Weigh the silicon carbide powder, industrial silicon powder and silicon micro powder according to the weight parts and grind them for later use. Put the silicon carbide powder and binder into a mixer and mix for 10-15 minutes. Then add the industrial silicon powder, silicon micro powder and additives, continue to mix for 15-20 minutes and then discharge the material. After re-mixing for 36 hours, the mixture is obtained. S2. Molding: The mixture obtained in step S1 is placed in a vibratory press for molding. The molding time is 9-10 hours. After demolding, it is naturally dried for 24 hours, and then placed at 200℃ for drying for 48 hours to obtain precast bricks. S3, Sintering: The precast bricks obtained in step S2 are placed in a sintering furnace for sintering. During sintering, N2 is introduced to keep the pressure inside the furnace slightly positive at 0.1MPa. First, the temperature is raised to 1000~1050℃ at a heating rate of 15~20℃ / min and held for 36h. Then, the temperature is raised to 1400~1420℃ at a heating rate of 4~6℃ / min and held for 36h to obtain the sintered base (1). S4. Installation: Install the riser tube body (2) on the upper part of the base (1) obtained in step S3, and install the coking removal component inside the base (1) to obtain the nitrogen-oxygen composite rare earth ceramic riser tube base.

7. The preparation process of a nitrogen-oxygen composite rare earth ceramic riser base according to claim 6, characterized in that, In step S1, the maximum particle size of the silicon carbide powder, industrial silicon powder, and silicon micro powder grinding does not exceed 3.5 mm.

8. The preparation process of a nitrogen-oxygen composite rare earth ceramic riser base according to claim 6, characterized in that, The brick shape formed in step S2 is 230mm long, 114mm wide, and 65mm high.

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