Pugging device for fly ash-based catalyst and forming equipment with pugging device

Abstract

The pugging device comprises a pugging cylinder, a feeding port and a discharging port are formed in the two ends of the pugging cylinder respectively, and the inner diameter of the pugging cylinder is gradually reduced in the direction from the feeding port to the discharging port to form a plurality of step faces in the radial direction; conveying blades are spirally arranged on the periphery of the grinding conveying shaft in the axial direction, the diameter of the grinding conveying shaft is gradually reduced in the conveying direction to form a plurality of radial grinding faces, a circle of grinding teeth are fixedly installed on each grinding face, the grinding conveying shaft is located in the pugging cylinder, and the two ends of the grinding conveying shaft are rotationally connected with the inner walls of the two ends of the pugging cylinder correspondingly. The plurality of grinding surfaces and the plurality of step surfaces are in one-to-one correspondence to form a plurality of grinding gaps, and the grinding teeth on each grinding surface rotationally abut against the corresponding step surface; the pugging device provided by the invention can be used for grinding and softening a fly ash mixed material, and discharging residual gas in the material in the grinding process, so that subsequent processing steps can be smoothly carried out.

Description

Technical Field

[0001] The invention belongs to the technical field of manufacturing fly ash-based catalysts, and particularly relates to a clay kneading device for fly ash-based catalysts and a forming device with the same. Background Art

[0002] Fly ash is a by-product of high-temperature combustion in coal-fired power plants. With the increase in coal consumption, fly ash discharged from coal-fired power plants has become one of the largest industrial solid wastes. Realizing the high-value utilization of fly ash has become a research hotspot in recent years. In the prior art, there are many studies on the high-value utilization of fly ash, mainly for making fly ash-based catalysts. The preparation method usually involves subjecting fly ash to iron and silicon removal treatment, mixing it with materials such as bentonite, binder, and pore-forming agent, then aging, and finally putting the aged materials into a conventional extruder to be extruded into a mold for forming.

[0003] However, the mixed materials after aging have high strength, are relatively tough in texture, have low fluidity, and have residual gas inside. Using a conventional extruder results in poor extrusion effect, and it will also damage the screw of the extruder due to large axial stress. Moreover, when drying and firing are carried out with gas still existing inside the mixed materials, air bubbles will also be present in the finally produced catalyst, affecting the product quality. Therefore, corresponding improvements need to be made to the steps before the extrusion molding of the mixed materials when making fly ash-based catalysts currently, and the fly ash mixed materials before extrusion need to be degassed and softened. Summary of the Invention

[0004] The purpose of the invention is to provide a clay kneading device for fly ash-based catalysts, aiming to solve the problem that the aged fly ash mixed materials are too hard in texture and are not easily extruded smoothly through an extruder in the prior art.

[0005] To solve the above problems, the invention adopts the following technical solutions:

[0006] A clay kneading device for fly ash-based catalysts includes a clay kneading cylinder. Feed ports and discharge ports are respectively provided at both ends of the clay kneading cylinder, and its inner diameter gradually decreases along the direction from the feed port to the discharge port to form a plurality of stepped surfaces in the radial direction; a grinding and conveying shaft, on the outer periphery of which conveying blades are spirally arranged along its axial direction, and the diameter of the grinding and conveying shaft gradually decreases along the conveying direction to form a plurality of radial grinding surfaces. A ring of grinding teeth is fixedly installed on each grinding surface. The grinding and conveying shaft is located inside the clay kneading cylinder, and its two ends are respectively rotatably connected to the inner walls at both ends of the clay kneading cylinder. The plurality of grinding surfaces correspond to the plurality of stepped surfaces one by one to form a plurality of grinding gaps, and the grinding teeth on each grinding surface rotate and abut against the corresponding stepped surface; a driving part, which is installed on the clay kneading cylinder, and its driving end is in transmission connection with the grinding and conveying shaft.

[0007] The beneficial effects of the present invention are as follows: Multiple grinding surfaces with grinding teeth formed by multiple sections of grinding and conveying shafts cooperate with multiple stepped surfaces inside the clay kneading cylinder to additionally achieve a grinding effect during the stirring and conveying process. When the aged material enters the interior of the clay kneading cylinder through the feeding port, it comes into contact with the grinding and conveying shaft and then starts to be transported towards the discharging port while being preliminarily stirred, and successively enters the grinding gaps formed by multiple stepped surfaces and grinding surfaces. During this process, it will be ground under the combined action of the grinding teeth and the stepped surfaces to achieve the purpose of softening the fly ash mixture, and the gas remaining in the fly ash mixture can be discharged during the grinding process. Subsequently, it can be sent out through the discharging port. The fly ash mixture processed by the clay kneading device is finer, the fluidity is improved, the internal materials are more fully mixed, and at the same time, the excess gas is discharged, and the plastic effect is better, and no bubbles will be generated inside after subsequent firing.

[0008] Further, the grinding teeth are all arranged obliquely along the rotation direction of the grinding and conveying shaft.

[0009] A further beneficial effect of the present invention is that the obliquely arranged grinding teeth can provide additional shear force during the grinding process to further improve the grinding effect.

[0010] Further, the number of grinding teeth on each grinding surface increases as its diameter decreases.

[0011] A further beneficial effect of the present invention is that the grinding effect is gradually improved by the gradually increasing number of teeth.

[0012] Further, the axial spacing of multiple groups of the conveying vanes gradually decreases along the conveying direction.

[0013] A further beneficial effect of the present invention is that by gradually reducing the spacing of the stirring and conveying vanes, it can adapt to the gradually refined fly ash mixture and meet the conveying requirements.

[0014] Further, it further includes a spray head. A storage cavity is formed in the barrel wall of the clay kneading cylinder. Glycerol is stored in the storage cavity. The spray heads are multiple and are arranged at intervals along the axial direction inside the clay kneading cylinder, and the installation ends are fixedly connected to the inner wall of the clay kneading cylinder and communicated with the storage cavity.

[0015] A further beneficial effect of the present invention is that by using the glycerol in the storage cavity and the spray heads, an appropriate amount of glycerol can be released into the fly ash mixture during the clay kneading process, further playing a role in softening the material and facilitating subsequent smooth extrusion molding.

[0016] Further, it further includes an exhaust nozzle. The exhaust nozzle is fixedly connected to the side wall of the clay kneading cylinder near the discharging port and communicated with the interior of the clay kneading cylinder.

[0017] A further beneficial effect of the present invention is that an exhaust nozzle is used to assist in discharging the gas released by the fly ash mixture during the grinding process to the outside of the clay kneading cylinder.

[0018] Furthermore, a plurality of exhaust channels are provided along the conveying direction inside the cylinder wall of the clay kneading cylinder, a plurality of air inlets are provided on the outer periphery of the plurality of step surfaces, one ends of the plurality of exhaust channels are respectively communicated with the plurality of air inlets, and the other ends are communicated with the exhaust nozzle.

[0019] A further beneficial effect of the present invention is that in order to prevent the exhaust nozzle from being blocked during subsequent use, a plurality of exhaust channels are provided, and the air inlets of the exhaust channels are arranged on the outer periphery of the step surface. Through the above design, the gas discharged during the grinding process can be received, and the fly ash mixture during transportation can be effectively prevented from entering the exhaust channels. The exhaust nozzle is connected to a plurality of exhaust channels, so there is no need to directly communicate with the inside of the clay kneading cylinder, fundamentally solving the problem that the exhaust nozzle may be blocked in the later stage.

[0020] Furthermore, the inside of the grinding and conveying shaft is hollow. The driving part of the grinding and conveying shaft includes a driving motor, a transmission shaft and a connecting rod. The driving motor is fixedly connected to the end of the clay kneading cylinder. The transmission shaft is located at one end of the clay kneading cylinder and is fixedly connected to the output shaft of the driving motor. There are multiple groups of connecting rods, which are arranged at intervals along the axial direction of the transmission shaft. One end of each connecting rod is fixedly connected to the transmission shaft. The grinding and conveying shaft is sleeved outside the transmission shaft, and its inner wall is fixedly connected to the other ends of the multiple groups of connecting rods.

[0021] A further beneficial effect of the present invention is that by setting the grinding and conveying shaft to be hollow and cooperating with the transmission shaft and the connecting rod for transmission, materials can be effectively saved and energy waste can be reduced. The grinding and conveying shaft can also be detached separately for cleaning and maintenance, which is very convenient and reduces the later maintenance cost.

[0022] The present invention also provides a forming and extrusion device for a fly ash-based catalyst, including a frame; the aforementioned clay kneading device, the clay kneading cylinder is fixedly installed on the frame; an extrusion device, the extrusion device includes an extrusion cylinder, a screw and a screw driving part. The extrusion cylinder is located below the clay kneading cylinder and is fixedly installed on the frame. One end of its side wall is communicated with the discharge port, and the other end is open. One end of the screw is rotatably connected to the closed end of the extrusion cylinder. The screw driving part is fixedly connected to the end of the extrusion cylinder, and its output end is in transmission connection with one end of the screw; a forming die, the feeding end of the forming die is butted against the barrel opening of the extrusion cylinder.

[0023] The beneficial effects of the present invention are as follows: A forming and extrusion device for fly ash-based catalysts is provided. The extrusion cylinder receives the softened fly ash mixture flowing out from the clay refining device and enters the forming die through the extrusion port to finally complete the extrusion forming.

[0024] The raw materials for preparing the fly ash-based catalyst using the above device are fly ash, calcium-based bentonite, deionized water, neutral silica sol, pore-forming agent, manganese nitrate solution, and cerium nitrate solution. The manufacturing method is as follows:

[0025] S1. Grind the fly ash raw materials collected from the power plant, pass through a 40-mesh sieve, conduct high-temperature calcination, then perform pickling, followed by solid-liquid separation, wash until neutral, and dry for standby.

[0026] S2. Mix the fly ash treated in S1 and calcium-based bentonite in a ratio of 4:1 and stir evenly.

[0027] S3. Add deionized water with a mass ratio of 14% to the mixture in S2.

[0028] S4. Add neutral silica sol with a mass ratio of 6% to the mixture in S3.

[0029] S5. Add a pore-forming agent with a mass ratio of 6% to the mixture in S4.

[0030] S6. Stir the mixture in S5 evenly and let it age for 24 hours.

[0031] S7. Feed the aged mixture in S6 into the feeding port of the clay refining device in batches. After softening and exhausting air through the clay refining device, it is extruded and formed through the extrusion device and the forming die.

[0032] S8. Place the extruded and formed material in S7 into the drying oven and dry it at 65°C for 30 minutes.

[0033] S9. Immerse the calcined material in S8 into the mixed solution of manganese nitrate solution and cerium nitrate solution by the equal-volume impregnation method for 24 hours, then take it out and dry. The molar ratio of manganese and cerium in the mixed solution is 1:1.

[0034] S10. Place the dried catalyst in S9 into the muffle furnace and bake it at a constant temperature of 450°C for 2 hours.

[0035] Compared with the prior art, the present invention has the following significant improvements:

[0036] 1. The extrusion device provided by the present invention can soften and exhaust air for the aged fly ash mixture before extrusion, which is convenient for subsequent extrusion. At the same time, it can also protect the screw of the extrusion device from being damaged due to large stress.

[0037] 2. In the clay kneading device of the present invention, a multi-stage grinding and conveying shaft and multi-stage annular bosses form multiple channels and stirring and transporting channels. During the horizontal transportation process, the fly ash mixed material is additionally ground multiple times, and its softening effect is significantly better than that of conventional stirring and conveying machines.

[0038] 3. In the clay kneading device of the present invention, multiple exhaust channels are formed by its own annular bosses and connected to the exhaust nozzles. The body of the exhaust nozzle does not need to be directly connected to the inside of the clay kneading cylinder, fundamentally solving the problem of exhaust nozzle blockage.

[0039] 4. In the clay kneading device of the present invention, an appropriate amount of glycerol is sprayed through a nozzle during the final stirring process to further improve the fluidity of the fly ash mixed material and make the subsequent extrusion smoother.

[0040] 5. The extrusion device of the present invention is equipped with two mold mounting parts and a forming mold that can be used interchangeably. Different forming molds can be replaced to meet production requirements, and seamless docking can be achieved during replacement without affecting continuous production. BRIEF DESCRIPTION OF THE DRAWINGS

[0041] Figure 1 It is a schematic diagram of the clay kneading device for fly ash-based catalysts provided by the present invention;

[0042] Figure 2 It is a schematic diagram of the grinding and conveying shaft in the clay kneading device for fly ash-based catalysts provided by the present invention;

[0043] Figure 3 It is a front view of the grinding and conveying shaft in the clay kneading device for fly ash-based catalysts provided by the present invention;

[0044] Figure 4 It is a side view of the grinding and conveying shaft in the clay kneading device for fly ash-based catalysts provided by the present invention;

[0045] Figure 5 It is a side sectional view of the clay kneading device for fly ash-based catalysts provided by the present invention;

[0046] Figure 6 It is Figure 5 an enlarged schematic view of part A in

[0047] Figure 7 It is an overall schematic diagram of the forming equipment for fly ash-based catalysts provided by the present invention;

[0048] Figure 8 It is Figure 7 an enlarged schematic view of part B in

[0049] Figure 9 It is a front view of the forming equipment for fly ash-based catalysts provided by the present invention;

[0050] Figure 10 The side cross-sectional view of the forming equipment for fly ash-based catalysts provided by the present invention;

[0051] Figure 11 is Figure 1 The enlarged schematic view of the position C in

[0052] Reference numerals

[0053] 1. Frame;

[0054] 2. Clay kneading device; 21. Clay kneading cylinder 211. Feed inlet; 212. Discharge outlet; 213. Storage cavity; 214. Exhaust passage; 22. Grinding and conveying shaft; 221. Conveying blade; 222. Grinding surface; 223. Grinding teeth; 23. Transmission part; 231. Transmission shaft; 232. Connecting rod; 24. Spray head; 25. Exhaust nozzle;

[0055] 3. Extrusion device; 31. Extrusion cylinder; 32. Screw;

[0056] 4. Forming die; 41. Mud passing plate; 411. Mud passing channel; 42. Forming frame; 43. Die nail

[0057] 5. Die assembly rack; 51. Base; 52. Clamping block. Detailed implementation manners

[0058] Next, the technical solutions in the embodiments of the present invention will be clearly and completely described in conjunction with the accompanying drawings in the embodiments of the present invention. Obviously, the described embodiments are only a part of the embodiments of the present invention, rather than all the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those of ordinary skill in the art without creative efforts belong to the scope of protection of the present invention.

[0059] As shown in the figure, the present invention provides a clay kneading device for fly ash-based catalysts, mainly including:

[0060] The clay kneading cylinder 21, the grinding and conveying shaft 22 and the driving part. The grinding and conveying shaft 22 is coaxially and rotatably assembled in the clay kneading cylinder 21, and the driving part is installed on the outer shell of the clay kneading cylinder 21, and its driving end drives the grinding and conveying shaft 22 to rotate.

[0061] Specifically, the clay kneading cylinder 21 is a long cylinder. A feeding port 211 and a discharging port 212 are respectively arranged on the side walls of the clay kneading cylinder 21 near both ends. The feeding port 211 is equipped with a feeding hopper. The inner cavity of the clay kneading cylinder 21 is axially divided into four sections, namely, the first cavity, the second cavity, the third cavity and the fourth cavity. And the diameters of the four inner cavities gradually decrease along the direction from the feeding port 211 to the discharging port 212, and a total of three radial annular step surfaces are formed. That is, the inner diameter of the second cavity extends a step surface a towards the central axis relative to the inner diameter of the first cavity. Similarly, the inner diameter of the third cavity extends a step surface b towards the central axis relative to the inner diameter of the second cavity, and the inner diameter of the fourth cavity extends a step surface c towards the central axis relative to the inner diameter of the third cavity. The ring widths of the three step surfaces in the radial direction are the same.

[0062] The grinding and conveying shaft 22, the shape of the grinding and conveying shaft 22 is adapted to the shape of the inner cavity of the clay kneading cylinder 21, and is divided into four sections, namely, the first section of the shaft body, the second end of the shaft body, the third section of the shaft body and the fourth section of the shaft body. The diameter of each section of the shaft body gradually decreases and finally forms a plurality of grinding surfaces 222. That is, the diameter of the first section of the shaft body is the largest, and the diameter of the fourth section of the shaft body is the smallest. The part where the diameter of the first section of the shaft body exceeds the diameter of the second section of the shaft body generates a grinding surface a. The part where the diameter of the second section of the shaft body exceeds the diameter of the third section of the shaft body generates a grinding surface b. The part where the diameter of the third section of the shaft body exceeds the diameter of the fourth section of the shaft body generates a grinding surface c. And a ring of grinding teeth 223 is fixedly installed on each grinding surface 222. The grinding and conveying shaft 22 is rotationally assembled in the clay kneading cylinder 21, and its two ends are respectively rotationally connected to the inner walls at both ends of the clay kneading barrel 21. The first section of the shaft body is located in the first cavity, the second section of the shaft body is located in the second cavity, the third section of the shaft body is located in the third cavity, and the fourth section of the shaft body is located in the fourth cavity. The three grinding surfaces 222 correspond to the three step surfaces one by one, and the three grinding surfaces 222 are respectively in rotational abutment with the grinding teeth on their corresponding step surfaces. Since the inner diameters of the first cavity, the second cavity, the third cavity and the fourth cavity respectively match the outer diameters of the first section of the shaft body, the second section of the shaft body, the third section of the shaft body and the fourth section of the shaft body, and the lengths in the axial direction also respectively match correspondingly, the axial gap between the grinding surface a and the step surface a is small and the radial overlapping area is large, so as to form a first grinding gap in the radial direction. Similarly, a second grinding gap in the radial direction is formed between the grinding surface b and the step surface b, and a third grinding gap in the radial direction is formed between the grinding surface c and the step surface c. At the same time, the radial gap between the inner diameter of the first cavity and the outer periphery of the first section of the shaft body is small and the axial overlapping area is large, forming a first conveying gap in the axial direction. Similarly, a second conveying gap, a third conveying gap and a fourth conveying gap in the axial direction are formed between the inner diameter of the second cavity and the outer periphery of the second section of the shaft body.

[0063] Through the above technical solution, the present invention utilizes the inner cavities of the multi-segment grinding and conveying shaft 22 and the pug mill cylinder 21 to form a plurality of grinding gaps and conveying gaps. After the aged fly ash mixture enters the interior of the pug mill cylinder 21 through the feed port 211, it first enters the first conveying gap, is axially transported along the first section of the shaft body, then enters the first grinding gap, moves in the radial direction, and is subjected to the combined action of the grinding teeth 223 and the step surface a for the first grinding during this process. Subsequently, it enters the second conveying gap, is continuously stirred forward through the second section of the shaft body in the second conveying gap, then enters the second grinding gap, is refined and ground again, and then enters the third conveying gap. This process is repeated to achieve the purpose of refining the fly ash mixture. During the grinding process, the gas inside the aged fly ash mixture can also be released. The fly ash mixture processed by the pug mill device 2 is finer, its fluidity is improved, the internal materials are more fully mixed, and at the same time, the excess gas is discharged, and the plastic effect is better.

[0064] In some other embodiments, a circle of grinding teeth 223 on each grinding surface 222 is arranged obliquely along the rotation direction of the grinding and conveying shaft. In this embodiment, the obliquely arranged grinding teeth can endow the grinding teeth 223 with an additional shearing force during operation, which can further improve the crushing effect.

[0065] In some other embodiments, the density of the grinding teeth 223 on the multiple grinding surfaces 222 increases as the diameter of the grinding surface 222 decreases. In this embodiment, the fly ash mixture is gradually refined through the gradually increasing density of the grinding teeth.

[0066] In some embodiments, the grinding and conveying shaft 22 includes a shaft body and conveying blades 221. The shaft body is divided into 4 sections and the diameter of each section of the shaft body decreases gradually. The conveying blades 221 are also divided into four groups and are respectively installed on each section of the shaft body. Specifically, the stirring and conveying blades 222 are spiral blades, which are spirally wound along the axial direction of each section of the shaft body and fixed. In this embodiment, the spiral conveying blades 221 can simultaneously play the roles of conveying and stirring in each conveying gap, in cooperation with the inner wall of the pug mill cylinder 21, and continuously stir and mix the fly ash mixture during the conveying process.

[0067] On the basis of the previous embodiment, the axial spacing of the conveying blades 221 installed on the outer peripheries of the first section of the shaft body, the second section of the shaft body, the third section of the shaft body, and the fourth section of the shaft body decreases in sequence. In the embodiment: by gradually reducing the spacing of the conveying blades 221, it can adapt to the gradually refined fly ash mixture and improve the transportation effect.

[0068] In some other embodiments, a storage cavity 213 is formed inside the barrel wall of the clay kneading barrel 21, and 3 to 5 spray nozzles 24 communicating with the storage cavity 213 are fixedly installed on the inner wall. Glycerol is stored in the storage cavity 213, and the spray nozzles 24 can spray an appropriate amount of glycerol into the interior of the clay kneading barrel 21 during the stirring process. Specifically, the storage cavity 213 is separately formed in the barrel wall corresponding to the fourth cavity. When the fly ash mixture enters the fourth conveying gap, due to the previous grinding and stirring, the fly ash mixture has become relatively fine. Then, a small amount of glycerol is added appropriately, and the conveying blades 221 on the outer periphery of the fourth shaft body are used to stir evenly, further improving the fluidity of the fly ash mixture and facilitating subsequent extrusion.

[0069] In some other embodiments, an exhaust nozzle 25 is additionally provided to assist in exhausting. The exhaust nozzle 25 is installed on the clay kneading barrel 21, specifically on the side wall near one end of the discharge port 212. The gas discharged from the fly ash mixture during the grinding process is assisted to be discharged through the exhaust nozzle 25.

[0070] On the basis of the previous embodiment, in order to solve the problem that the exhaust nozzle 25 may be blocked during long-term use, a plurality of auxiliary exhaust channels 214 are additionally provided to communicate with the exhaust nozzle 25 for exhausting. Specifically, an air inlet is formed on each of the three stepped surfaces, and 3 exhaust channels 214 are correspondingly formed along the axial direction of the clay kneading barrel 21 corresponding to the air inlets and communicated with the exhaust nozzle 25. Since the air inlets of the exhaust channels 214 are arranged on the outermost periphery of the plurality of stepped surfaces, it can effectively prevent the fly ash mixture during transportation from entering the exhaust channels. And because there are a plurality of exhaust channels 214 that do not need to worry about blockage, the exhaust nozzle 25 body does not need to communicate with the interior of the clay kneading barrel 21, fundamentally solving the problem that the exhaust nozzle 25 may be blocked in the later stage.

[0071] In some other embodiments, the inside of the grinding and conveying shaft 22 is hollow, the driving part is a rotary motor and a speed reducer, and a transmission part 23 is further included. The transmission part 23 includes a transmission shaft 231 and four groups of connecting rods 232. The rotary motor is fixedly connected to the end of the clay kneading cylinder 21, and a speed reducer is installed on its motor shaft. The output shaft of the speed reducer passes through the end of the clay kneading cylinder 21 and enters the clay kneading cylinder 21. The transmission shaft 231 is located inside the clay kneading cylinder 21, one end of which is fixedly connected to the output shaft of the speed reducer through a shaft sleeve, and the other end is rotatably connected to the inside of the other side opposite to the clay kneading cylinder 21. The four groups of connecting rods 232 are arranged in sequence along the axial direction of the transmission shaft 231. One end of each group is fixedly connected to the shaft body of the transmission shaft 231. The hollow grinding and conveying shaft 22 is sleeved outside the transmission shaft 231, and its inner wall is detachably connected to the other ends of the four groups of connecting rods 232. Specifically, the four groups of connecting rods 232 respectively correspond to a section of the shaft body. In this embodiment: By setting the grinding and conveying shaft 22 to be hollow, materials can be saved and energy waste can be reduced. Moreover, the hollow grinding and conveying shaft 22 can be disassembled separately for cleaning and maintenance, which is very convenient and reduces the later maintenance cost.

[0072] On the basis of the previous embodiment, for the convenience of disassembly and assembly, the grinding and conveying shaft 22 is divided into two identical parts of the outer shell along the radial direction, which can be spliced. The inner wall of the outer shell has slots for installing the connecting rods 232, which is convenient for fixing the connecting rods 232. The connecting rods 232 can be fixed by bolts after being inserted into the slots, and the two parts of the outer shell are connected through bolt blind holes on the end face.

[0073] As shown in the figure, the present invention also provides a fly ash-based catalyst molding equipment, including a frame 1, a mud kneading device 2 in any one of the aforementioned embodiments, an extrusion device 3, a molding mold 4 and a mold assembly frame 5. The mud kneading cylinder 21 is arranged vertically and fixedly installed on the frame 1, the feed port 211 is arranged upward, and the discharge port 212 is arranged downward. The extrusion device 3 includes an extrusion barrel 31, a screw 32 and a screw driving part. The extrusion barrel 31 is arranged horizontally and fixedly installed on the frame 1, located below the mud kneading cylinder 21, and the side wall of one end thereof is connected to the discharge port 212, and a screw driving part 33 is installed at this end. The screw driving part is also composed of a rotating motor and a reducer. The output shaft of the reducer passes through the outer shell of the extrusion barrel 31 and enters the interior of the extrusion barrel 31. The other end of the extrusion barrel 31 is open, and the screw 32 is rotatably assembled in the extrusion barrel 31, and one end is transmission-connected to the output shaft of the reducer. The molding mold 4 is placed in front of the extrusion barrel 31 through the mold assembly frame 5, and its feed end is butted against the barrel mouth of the extrusion barrel 31. In the present embodiment, a molding device for a fly ash-based catalyst is provided, in which the softened fly ash mixed material flowing out from the mud kneading device 2 is received by the extrusion barrel 31 and enters the molding die 4 through the barrel mouth of the extrusion barrel 31 to finally complete the extrusion molding. Compared with the traditional technology, the fly ash mixed material is softened and exhausted before extrusion molding, and the fluidity of the material is significantly improved, and the resistance is reduced during extrusion, which can protect the screw from damage. In addition, due to the improvement of fluidity, the extrusion is smoother and the production efficiency is significantly improved.

[0074] In some embodiments, each molding mold 4 includes a mud passing plate 41, a molding frame 42 and a plurality of mold pins 43. A plurality of mud passing channels 411 are opened on the plate surface of the mud passing plate 41. The plurality of mud passing channels 411 constitute a circular mud passing area. The shape and size of the mud passing area are adapted to the shape of the barrel mouth of the extrusion barrel 31, and are used to receive the material extruded from the extrusion barrel 31. The molding frame 42 is fixed on the side of the mud passing plate 41 away from the extrusion barrel 31. The plurality of mold pins 43 are distributed in an array and are located within the range of the molding frame 42. They are also fixedly installed on the side of the mud passing plate 41 away from the extrusion barrel 31. Specifically, one end of the mold pin 43 is fixed to the portion between the channel openings of the plurality of mud passing channels 411 on the plate surface of the mud passing plate 41.

[0075] In this embodiment: the mud passing area of the mud passing plate 41 is adapted to the shape of the barrel mouth of the extrusion barrel 31, and the fly ash mixed material extruded from the extrusion barrel 31 is preferentially extruded after passing through multiple mud passing channels 411, and then further formed into the required porous structure through the gaps formed between multiple die pins 43, and the overall size is limited by the forming frame 42 to finally form a finished product.

[0076] In some embodiments, the mold assembly rack includes a base 51 and two clamping blocks 52. The base 51 is installed on the upper surface of the frame 1. The two clamping blocks 52 are arranged in parallel and are respectively slidably connected to the upper surface of the base 51 along the radial direction of the barrel diameter of the extrusion barrel 31. On the opposite sides of the two clamping blocks 52, grooves adapted to the shape of the mud passing plate 41 are respectively formed and can be locked by a locking structure. The shapes and locking methods of the two clamping blocks 52 are not limited.

[0077] Based on the previous embodiment, two mold assembly racks 5 can also be provided, which are respectively slidably connected to the upper surface of the frame 1 along the radial direction of the barrel opening of the extrusion barrel 31. The outer periphery of the mud passing plate 41 can be detachably connected to the two mold assembly racks 5 respectively. By providing two mold assembly racks 5 to cooperate with the forming mold 4, they can be used alternately and quickly docked. When it is necessary to replace the forming mold 4, another mold assembly rack 5 can be directly used to cooperate with the new forming mold 4 to continue the extrusion work, which can avoid terminating the work process and achieve uninterrupted extrusion production.

[0078] The present invention also provides a method for preparing a fly ash-based catalyst applicable to the aforementioned equipment. The preparation raw materials are fly ash, calcium-based bentonite, deionized water, neutral silica sol, pore-forming agent, manganese nitrate solution, and cerium nitrate solution. The manufacturing method is as follows:

[0079] S1. Grind the fly ash raw materials collected from the power plant, pass through a 40-mesh sieve, perform high-temperature calcination, then perform pickling, and then perform solid-liquid separation, wash until neutral, and dry for standby.

[0080] S2. Mix the fly ash treated in S1 and calcium-based bentonite in a ratio of 4:1 and stir evenly.

[0081] S3. Add deionized water with a mass ratio of 14% to the mixture in S2.

[0082] S4. Add neutral silica sol with a mass ratio of 6% to the mixture in S3.

[0083] S5. Add a pore-forming agent with a mass ratio of 6% to the mixture in S4.

[0084] S6. Stir the mixture in S5 evenly and let it age for 24 h.

[0085] S7. Send the mixture aged in S6 into the feeding port 211 of the clay refining device 2 in batches. After being softened and degassed by the clay refining device, it is extruded and formed through the extrusion device 3 and the forming mold 4.

[0086] S8. Put the material extruded and formed in S7 into a drying oven and dry it at 65 °C for 30 min.

[0087] S9. The calcined material in S8 is immersed in a mixed solution of manganese nitrate solution and cerium nitrate solution by the equal-volume impregnation method for 24 h and then taken out for drying. The molar ratio of manganese to cerium in the mixed solution is 1:1.

[0088] S10. The dried catalyst in S9 is placed in a muffle furnace and calcined at a constant temperature of 450 °C for 2 h.

[0089] Compared with the prior art, the present invention has the following remarkable improvements:

[0090] 1. The extrusion device provided by the present invention can soften and exhaust the aged fly ash mixed material before extrusion, facilitating subsequent extrusion. At the same time, it can also protect the screw of the extrusion device from being damaged due to excessive stress.

[0091] 2. In the present invention, the clay kneading device uses multiple-stage grinding and conveying shafts and multiple-stage annular bosses to form multiple channels and stirring and transporting channels. During the horizontal transportation process, the fly ash mixed material is additionally ground multiple times, and its softening effect is significantly better than that of conventional stirring and conveying machines.

[0092] 3. In the clay kneading device of the present invention, multiple exhaust channels are formed by its own annular bosses and connected to the exhaust nozzle. The body of the exhaust nozzle does not need to be directly connected to the inside of the clay kneading cylinder, fundamentally solving the problem of exhaust nozzle blockage.

[0093] 4. During the final stirring process, an appropriate amount of glycerol is sprayed through the nozzle to further improve the fluidity of the fly ash mixed material, making the subsequent extrusion smoother.

[0094] Although the embodiments of the present invention have been shown and described, those of ordinary skill in the art can understand that various changes, modifications, substitutions, and variations can be made to these embodiments without departing from the principles and purposes of the present invention. The scope of the present invention is defined by the claims and their equivalents.

Claims

1. A kneading device for fly ash-based catalysts, characterized in that Comprising: A clay kneading cylinder (21) with a feed inlet (211) and a discharge outlet (212) respectively opened at both ends. Its inner diameter gradually decreases along the direction from the feed inlet (211) to the discharge outlet (212), forming multiple stepped surfaces in the radial direction; A grinding and conveying shaft (22) with conveying blades (221) spirally arranged along its axial direction on the outer periphery. The diameter of the grinding and conveying shaft (22) gradually decreases along the conveying direction, forming multiple radial grinding surfaces (222). A ring of grinding teeth (223) is fixedly installed on each grinding surface (222). The grinding and conveying shaft (22) is located inside the clay kneading cylinder (21), and its two ends are respectively rotatably connected to the inner walls at both ends of the clay kneading cylinder (21). The multiple grinding surfaces (222) correspond to the multiple stepped surfaces one by one to form multiple grinding gaps, and the tooth surfaces of the grinding teeth (223) on each grinding surface (222) are rotationally abutted against the corresponding stepped surfaces; A driving part installed on the clay kneading cylinder (21), and its driving end is in transmission connection with the grinding and conveying shaft (22).

2. The pugging device for fly ash-based catalyst according to claim 1, characterized in that, The grinding teeth (223) are all arranged obliquely along the rotation direction of the grinding and conveying shaft (22).

3. The clay kneading device for fly ash-based catalyst according to claim 2, characterized in that, The number of teeth of the grinding teeth (223) on the multiple grinding surfaces (222) increases as the diameter of the grinding surface (222) decreases.

4. A pugging device for fly ash-based catalyst, according to claim 1, characterized in that, The axial spacing of the conveying blades (221) gradually decreases along the conveying direction.

5. The pug mill device for fly ash-based catalyst according to claim 1, characterized in that, It further includes a spray head (24). A storage cavity (213) is opened in the cylinder wall of the clay kneading cylinder (21). Glycerol is stored in the storage cavity (213). There are multiple spray heads (24), which are arranged at intervals along the axial direction inside the clay kneading cylinder (21), and their installation ends are fixedly connected to the inner wall of the clay kneading cylinder (21) and communicated with the storage cavity (213).

6. The pug mill device for fly ash-based catalyst according to claim 1, characterized in that, It further includes an exhaust nozzle (25) fixedly connected to the side wall of the clay kneading cylinder (21) near the discharge outlet (212) and communicated with the inside of the clay kneading cylinder (21).

7. A pugging device for fly ash-based catalysts according to claim 6, wherein, Multiple exhaust channels (214) are axially opened in the cylinder wall of the clay kneading cylinder (21). Air inlets are opened on the outer periphery of the multiple stepped surfaces. One end of each of the multiple exhaust channels (214) is respectively communicated with the multiple air inlets, and the other end is communicated with the exhaust nozzle (25).

8. A pug mill device for a fly ash-based catalyst according to any one of claims 1-7, characterized in that, The inside of the grinding and conveying shaft (22) is hollow. The clay kneading device further includes a transmission part (23), which includes a transmission shaft (231) and a connecting rod (232). The transmission shaft (231) is located inside the clay kneading cylinder (21), and one end of it is in transmission connection with the output end of the driving part. There are multiple groups of connecting rods (232), which are arranged at intervals along the axial direction of the transmission shaft (231). One end of each of them is fixedly connected to the shaft body of the transmission shaft (231). The grinding and conveying shaft (22) is sleeved outside the transmission shaft (231), and its inner wall is detachably connected to the other ends of the multiple groups of connecting rods (232).

9. A forming device, characterized in that, Comprising: A frame (1); The clay kneading device (2) according to any one of claims 1 to 8, wherein the clay kneading cylinder (21) is fixedly mounted on the frame (1); An extrusion device (3), the extrusion device (3) comprising an extrusion barrel (31), a screw (32) and a screw driving unit, the extrusion barrel (31) being located below the kneading barrel (21) and being fixedly mounted on the frame (1), the side wall of one end of which is connected to the discharge port (212), and the other end of which is open, the screw (32) being located inside the extrusion barrel (31), one end of which is rotatably connected to the inner wall of the closed end of the extrusion barrel (31), the screw driving unit being mounted on the extrusion barrel (31), and the driving end of which is drivingly connected to the screw (32); A mold assembly frame (5), wherein the mold assembly frame (5) is mounted on the upper surface of the frame (1); A forming die (4) is detachably connected to the die assembly frame (5), and its feed end is butted against the barrel opening of the extrusion barrel (31).

10. A molding device according to claim 9, characterized in that, The raw materials for preparing the fly ash-based catalyst are fly ash, calcium-based bentonite, deionized water, neutral silica sol, pore-forming agent, manganese nitrate solution and cerium nitrate solution. The manufacturing method of the fly ash-based catalyst is as follows: S1. The fly ash raw materials collected from the power plant are ground and passed through a 40-mesh sieve. After high-temperature calcination, they are acid-washed, followed by solid-liquid separation, washed to neutrality and dried for use. S2. Mix the fly ash and calcium-based bentonite treated in S1 in a ratio of 4:1 and stir evenly; S3. Add 14% deionized water by mass to the mixture in S2: S4. Add 6% by mass of neutral silica sol to the mixture in S3: S5. Add 6% by mass of a pore-forming agent to the mixture in S4: S6. Stir the mixture in S5 and let it age for 24 hours: S7. The stale mixture in S6 is fed into the feed port of the mud-making device in batches, and after softening and exhausting the mud-making device, it is extruded through an extrusion device and a molding die; S8. The extruded material in S7 is placed in a drying oven and dried at 65°C for 30 min; S9. The calcined material in S8 is immersed in a mixture of manganese nitrate solution and cerium nitrate solution by equal volume impregnation method for 24 hours, and then taken out and dried. The molar ratio of manganese to cerium in the mixture is 1:

1. S10. Place the dried catalyst in S9 into a muffle furnace and calcine at 450° C. for 2 h.

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