Preparation method and equipment of magnesite enhanced ceramsite proppant

Abstract

The invention discloses a magnesite enhanced ceramsite proppant preparation method and equipment, and relates to the technical field of ceramsite proppants, the magnesite enhanced ceramsite proppant preparation equipment comprises a support, a first granulation disc and a second granulation disc are obliquely and rotatably connected to the support, and the second granulation disc is located under the first granulation disc; a vortex-shaped sieve tray synchronously rotating with the first granulation tray is arranged between the first granulation tray and the second granulation tray, a plurality of sieve holes are uniformly formed in the vortex-shaped sieve tray, a discharge port is formed in the inner side of the vortex-shaped sieve tray, and a material collecting tray is arranged at the position, corresponding to the discharge port, between the vortex-shaped sieve tray and the second granulation tray; a mother nucleus forming device fixedly connected with the support is arranged above the first granulation disc and comprises a charging barrel, and the inner side of the charging barrel is rotationally connected with a rotating shaft. According to the preparation method and equipment of the magnesite enhanced ceramsite proppant, relatively high strength can be obtained while low apparent density can be maintained, and meanwhile, the blank forming efficiency can be improved.

Description

Technical Field

[0001] This invention relates to the field of ceramic proppant technology, specifically to a method and equipment for preparing magnesite-reinforced ceramic proppant. Background Technology

[0002] In the field of oil and gas extraction, ceramsite proppant is a key material in fracturing operations, and it must simultaneously meet the core requirements of low apparent density and high compressive strength. Low apparent density reduces the energy consumption of fracturing fluid transportation, facilitating the delivery of proppant to deep fractures downhole; high compressive strength can withstand the high-pressure environment downhole, preventing proppant breakage and fracture blockage, and ensuring unobstructed oil and gas passages. However, in existing ceramsite proppant preparation technologies, density and strength often present a trade-off: increasing the porosity of raw materials to reduce density easily leads to a loose proppant skeleton structure and a significant decrease in compressive strength; increasing aggregate content to enhance strength leads to an increase in apparent density, increasing construction costs and difficulty. In addition, existing ceramsite proppants mostly adopt a single-layer structure design, making it difficult to balance porosity and density, further limiting the synergistic optimization of density and strength.

[0003] In terms of production equipment and process efficiency, existing ceramsite proppant is mostly granulated using disc granulators. The formation of its core largely depends on the rotation of the disc granulator to form powder into balls, which is a relatively slow and random process. This results in slow particle growth, making it difficult to meet the needs of large-scale industrial production. At the same time, the existing disc granulator granulation is not suitable for the formation of multi-layer structure ceramsite proppant.

[0004] Therefore, it is necessary to propose a method and equipment for preparing magnesite-reinforced ceramic proppant to solve the above problems. Summary of the Invention

[0005] (a) Technical problems to be solved The purpose of this invention is to provide a method and equipment for preparing magnesite-reinforced ceramsite proppant, so as to solve the problems mentioned in the background art.

[0006] (II) Technical Solution To achieve the above objectives, the present invention provides a method for preparing a magnesite-reinforced ceramsite proppant, comprising the following steps: S1. Ingredients: Weigh the kernel powder and shell powder according to the formula ratio; S2. Mixing and preparing wet materials: The core powder and the shell powder are fed into a mixer separately, and a binder is added for stirring and mixing to obtain wet core materials and wet shell materials respectively. S3. Core preparation: The wet core material is prepared into a core. S4. Core Granulation: The mother core is fed into a granulator and wet core material is added to allow the mother core to gradually grow to the standard size. S5. Screening: The granulated kernel particles are screened to remove particles larger than the preset diameter, so as to obtain kernel particles that meet the standard size. S6. Shell Coating: The screened kernel particles are fed into the granulator, and wet shell material is added to make the kernel particles uniformly coated with the shell layer and gradually grow to the target size. S7. Drying and sintering: The double-layer structure green body particles are dried, and the dried particles are sent to a rotary kiln for high-temperature calcination to obtain ceramsite support.

[0007] Preferably, the core powder comprises the following raw materials in parts by weight: 50-65 parts of bauxite, 10-20 parts of magnesite, 10-20 parts of potassium feldspar, and 5-15 parts of iron ore; the outer shell powder comprises the following raw materials in parts by weight percentage: 70-85 parts of bauxite, 15-25 parts of magnesite, 1-5 parts of potassium feldspar, and 1-5 parts of iron ore.

[0008] A magnesite-reinforced ceramsite proppant preparation device includes a support frame. A first granulation disc and a second granulation disc are rotatably connected to the support frame. The second granulation disc is located directly below the first granulation disc. A vortex screen disc that rotates synchronously with the first granulation disc is provided between the first granulation disc and the second granulation disc. The vortex screen disc has a plurality of screen holes evenly distributed on it. A discharge port is provided on the inner side of the vortex screen disc. A collection disc is provided at a position corresponding to the discharge port between the vortex screen disc and the second granulation disc. Above the first granulation disc is a core forming device fixedly connected to the support. The core forming device includes a material cylinder, a rotating shaft rotatably connected to the inner side of the material cylinder, a spiral blade fixedly connected to the outer side of the rotating shaft, and a plurality of extrusion ports opened at the discharge end of the material cylinder. A cutter fixedly connected to the rotating shaft is provided on the outer side of the extrusion port.

[0009] Preferably, a first rotating frame driven to rotate by a first hydraulic cylinder is rotatably connected to the support, a first motor is fixedly connected to the first rotating frame, and the first granulation disc and the vortex screen disc are both rotatably connected to the first rotating frame and driven to rotate by the first motor.

[0010] Preferably, the collecting tray is fixedly connected to the first rotating frame, and a guide groove is connected to one side of the collecting tray.

[0011] Preferably, a second rotating frame driven to rotate by a second hydraulic cylinder is rotatably connected to the support, a second motor is fixedly connected to the second rotating frame, and the second granulation disc is rotatably connected to the second rotating frame and driven to rotate by the second motor.

[0012] Preferably, scrapers are provided on the inner sides of both the first and second granulation discs.

[0013] Preferably, the cross-section of the vortex screen is arc-shaped.

[0014] Preferably, a conical seat is fixedly connected to the discharge end of the material cylinder.

[0015] (III) Beneficial Effects Compared with the prior art, the present invention provides a method and equipment for preparing magnesite-reinforced ceramsite proppant, which has the following beneficial effects: 1. The preparation method and equipment of the magnesite-reinforced ceramsite proppant adopts a "core + shell" double-layer design to form a porous core and a dense high-alumina / mullite shell, thereby reducing the overall particle density and increasing the compressive strength, thus achieving high strength while maintaining low apparent density.

[0016] 2. The method and equipment for preparing magnesite-reinforced ceramsite proppant include a core forming device for extrusion to form cores, which makes it easier for wet core material to adhere and accelerates particle growth, thereby increasing the yield per unit time. The stacked first and second granulation discs allow the finished core material to fall directly into the second granulation disc, eliminating the material conveying process and preventing the dried surface of the finished core material from affecting the adhesion of the wet outer shell. A vortex screen between the first and second granulation discs is used to screen out finished core material larger than the standard size, preventing the core diameter from being too large and affecting the outer shell thickness. Attached Figure Description

[0017] Figure 1 This is a three-dimensional schematic diagram of the structure of the present invention; Figure 2 This is a rear-view perspective view of the structure of the present invention; Figure 3 This is a cross-sectional schematic diagram of the structure of the present invention; Figure 4 This is a three-dimensional schematic diagram of the vortex sieve disc of the present invention; Figure 5 This is a three-dimensional schematic diagram of the material collection tray of the present invention; Figure 6 This is a cross-sectional schematic diagram of the core forming device of the present invention; Figure 7 This is a three-dimensional schematic diagram of the core forming device of the present invention.

[0018] In the diagram: 1. Nucleus forming device; 2. First granulation disc; 3. Vortex screen disc; 4. Second granulation disc; 5. Support; 6. First hydraulic cylinder; 7. First rotating frame; 8. Scraper; 9. Second rotating frame; 10. Second hydraulic cylinder; 11. Collection disc; 12. First motor; 13. Second motor; 14. Third motor; 15. Feed inlet; 16. Rotating shaft; 17. Spiral blade; 18. Material cylinder; 19. Conical seat; 20. Extrusion outlet; 21. Cutter; 22. Discharge outlet; 23. Screen hole; 24. Guide channel. Detailed Implementation

[0019] The technical solutions of the present invention will be clearly and completely described below with reference to the accompanying drawings of the embodiments of the present invention. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments.

[0020] Example 1 A method for preparing a magnesite-reinforced ceramsite proppant includes the following steps: Ingredients: The core powder consists of 55 parts bauxite, 15 parts magnesite, 15 parts potassium feldspar, and 10 parts iron ore by weight percentage; the outer shell powder consists of 75 parts bauxite, 20 parts magnesite, 3 parts potassium feldspar, and 3 parts iron ore by weight percentage.

[0021] Mixing and preparing wet materials: The core powder and the shell powder are fed into a mixer separately, and 2%-5% of the total mass of binder is added and stirred to prepare the core wet material and the shell wet material respectively. The moisture content is controlled between 8%-12%. The binder is a polyvinyl alcohol aqueous solution or a sodium carboxymethyl cellulose aqueous solution. Core preparation: The wet core material is prepared into cores with a particle size of 3-5 mm; Core granulation: The mother core is fed into a disc granulator and wet core material is added, so that the mother core gradually grows to 10-12mm; Screening: The granulated kernel particles are screened through a 12mm sieve to remove particles larger than 12mm in diameter and unqualified kernel particles larger than 12mm in diameter. Kernel particles with a diameter of 8-12mm that meet the standard are collected. Shell coating: The screened core particles are fed into the granulator and the outer shell wet material is added so that the surface of the core particles is evenly coated with the outer shell layer and gradually grows into a double-layer structure green particle of 15-17mm. Drying and sintering: The double-layer green pellets are dried, and the dried pellets are sent into a rotary kiln for high-temperature calcination at 1250-1300℃ for 3-5 hours to obtain the product.

[0022] Example 2 Unlike Example 1, the core powder consists of 50 parts bauxite, 20 parts magnesite, 20 parts potassium feldspar, and 15 parts iron ore by weight percentage; the outer shell powder consists of 70 parts bauxite, 25 parts magnesite, 5 parts potassium feldspar, and 5 parts iron ore by weight percentage.

[0023] Example 3 Unlike Example 1, the core powder consists of 65 parts bauxite, 10 parts magnesite, 10 parts potassium feldspar, and 5 parts iron ore by weight percentage; the outer shell powder consists of 85 parts bauxite, 15 parts magnesite, 1 part potassium feldspar, and 1 part iron ore by weight percentage.

[0024]

[0025] In the above embodiments, the content of the main components in the raw materials is as follows: The Al2O3 content in bauxite is 58.3%-65.2%, and the SiO2 content is approximately 15.5%-20.1%. Magnesite contains 45.8-48.2% MgO and approximately 5.7-8.1% SiO2.

[0026] The SiO2 content in potassium feldspar is approximately 63.5-65.5%, Al2O3 is approximately 17.1-18.3%, and potassium K2O is approximately 14.5-16.5%.

[0027] The Fe2O3 content in iron ore is 65.1-69.5%.

[0028] Magnesite-reinforced ceramsite proppant employs a dual-layer design of "core + shell." The core uses bauxite to provide Al2O3, forming a mullite framework to establish strength. Magnesite enhances its strength through Mg²⁺ doping to optimize the lattice. Potassium feldspar acts as a flux and promotes micropore formation, while iron ore aids in sintering and induces micropores through reduction and gas generation, laying the foundation for overall strength and low density. The shell improves surface density and smoothness by increasing the high-alumina / mullite content. The dense high-alumina / mullite shell provides extremely high compressive strength, effectively resisting formation closure pressure. The hard shell protects the relatively fragile porous core from crushing. Even if microcracks appear in the core, they are difficult to penetrate the dense shell, thus improving overall toughness. The porous core reduces the overall particle density, forming uniform closed pores through the fluxing and pore-forming effects of potassium feldspar and iron ore. Although the shell is dense, its thinness limits its contribution to overall weight. Ultimately, a "light inside, heavy outside" structure is achieved, maintaining low apparent density while obtaining high strength.

[0029] Please see the appendix Figure 1-7A magnesite-reinforced ceramsite proppant preparation device includes a support 5. A first granulation disc 2 and a second granulation disc 4 are rotatably connected to the support 5 at an incline. The second granulation disc 4 is located directly below the first granulation disc 2. A vortex screen 3, which rotates synchronously with the first granulation disc 2, is provided between the first granulation disc 2 and the second granulation disc 4. A plurality of screen holes 23 are evenly opened on the vortex screen 3. A discharge port 22 is provided on the inner side of the vortex screen 3. A collection disc 11 is provided between the vortex screen 3 and the second granulation disc 4 at a position corresponding to the discharge port 22. A core forming device 1, which is fixedly connected to the support 5, is provided above the first granulation disc 2. The core forming device 1 includes a material cylinder 18. A rotating shaft 16 is rotatably connected to the inner side of the material cylinder 18. A spiral blade 17 is fixedly connected to the outer side of the rotating shaft 16. A plurality of extrusion ports 20 are opened at the discharge end of the material cylinder 18. A cutter 21, which is fixedly connected to the rotating shaft 16, is provided on the outer side of the extrusion port 20. Specifically, the diameter of the vortex screen 3 is larger than the diameter of the first granulation disc 2; the rotating shaft 16 is driven to rotate by the third motor 14, and the feed section of the material cylinder 18 is fixedly connected to the feed port 15.

[0030] In use, the mixed core wet material is fed into the core forming device 1 and the first granulation disc 2. The rotating shaft 16 applies pressure to the powder through the spiral blades 17, causing the powder to be extruded from the extrusion port 20. The rotating shaft 16 drives the cutter 21 to rotate, and the cutter 21 cuts the extruded columnar material. The cut columnar material falls into the first granulation disc 2 as the core. The diameter and length of the cut columnar material are the same. The first granulation disc 2 rotates, driving the core to roll. During the rolling process, the core continuously adheres to new core wet material. After growing to a certain size, under the action of its weight and centrifugal force, it moves to the edge of the disc, and the finished core is automatically formed. The finished product kernels overflow from the edge of the disc into the vortex screen disc 3; the finished product kernels that meet the size standard pass through the screen holes 23 and fall into the second granulation disc 4. As the vortex screen disc 3 rotates continuously, the larger diameter particles gradually move towards its center and finally fall into the collection disc 11 from the discharge port 22. The mixed outer shell wet material is fed into the second granulation disc 4. The second granulation disc 4 rotates to drive the finished product kernels falling into the second granulation disc 4 to roll. During the rolling process, the mother kernel continuously adheres to new outer shell wet material. After growing to a certain size, under the action of its weight and centrifugal force, it moves to the edge of the disc, and the semi-finished particles automatically overflow from the edge of the disc.

[0031] By setting up a core forming device 1 to extrude and form a core, the wet material of the core is more easily attached, which accelerates the growth rate of the particles and thus increases the output per unit time. By stacking the first granulation disc 2 and the second granulation disc 4, the finished core can fall directly into the second granulation disc 4, eliminating the material conveying process and avoiding the drying of the finished core surface from affecting the adhesion of the wet material of the outer shell. By setting a vortex screen disc 3 between the first granulation disc 2 and the second granulation disc 4, finished cores larger than the standard size are screened out, avoiding the core diameter being too large and affecting the thickness of the outer shell.

[0032] In some embodiments, to facilitate adjustment of the tilt angle of the first granulation disc 2, a first rotating frame 7 driven by a first hydraulic cylinder 6 is rotatably connected to the support 5. A first motor 12 is fixedly connected to the first rotating frame 7. Both the first granulation disc 2 and the vortex screen disc 3 are rotatably connected to the first rotating frame 7 via bearings and are driven to rotate by the first motor 12. The two ends of the first hydraulic cylinder 6 are hinged to the support 5 and the first rotating frame 7, respectively. When adjusting the tilt angle of the first granulation disc 2, the first rotating frame 7 is driven to rotate by the first hydraulic cylinder 6, thereby adjusting the tilt angle of the first granulation disc 2.

[0033] Specifically, the collecting tray 11 is fixedly connected to the first rotating frame 7 so that the collecting tray 11 can remain parallel to the vortex screen 3, ensuring that it can collect the kernels sent out from the discharge port 22. A guide channel 24 is connected to one side of the collecting tray 11, and the kernels collected in the collecting tray 11 are discharged from the guide channel 24 under the action of gravity.

[0034] In some embodiments, a second rotating frame 9 driven to rotate by a second hydraulic cylinder 10 is rotatably connected to the support 5. A second motor 13 is fixedly connected to the second rotating frame 9. The second granulation disc 4 is rotatably connected to the second rotating frame 9 through a bearing and driven to rotate by the second motor 13. The two ends of the second hydraulic cylinder 10 are respectively hinged to the support 5 and the second rotating frame 9. When adjusting the tilt angle of the second granulation disc 4, the second rotating frame 9 is driven to rotate by the second hydraulic cylinder 10, so that the tilt angle of the second granulation disc 4 can be adjusted.

[0035] To prevent material from adhering to the inner walls of the first granulation disc 2 and the second granulation disc 4, scrapers 8 are provided on the inner sides of both the first granulation disc 2 and the second granulation disc 4. The scraper 8 located on the inner side of the first granulation disc 2 is fixedly connected to the first rotating frame 7, and the scraper 8 located on the inner side of the second granulation disc 4 is fixedly connected to the second rotating frame 9.

[0036] To avoid affecting the screening effect when adjusting the tilt angle of the vortex screen 3, the cross-section of the vortex screen 3 is arc-shaped. A second granulation disc 4 with an arc-shaped cross-section is used, with screen holes 23 evenly opened on its arc-shaped surface to allow the finished product kernels to pass through.

[0037] To prevent material stagnation due to dead zones at the discharge end of the material cylinder 18, a conical seat 19 is fixedly connected to the discharge end of the material cylinder 18. The conical seat 19 guides the flow to prevent material stagnation.

[0038] Although embodiments of the invention have been shown and described, it will be understood by those skilled in the art that various changes, modifications, substitutions and alterations can be made to these embodiments without departing from the principles and spirit of the invention, the scope of which is defined by the appended claims and their equivalents.

Claims

1. A method for preparing a magnesite-reinforced ceramsite proppant, characterized in that: Includes the following steps: S1. Ingredients: Weigh the kernel powder and shell powder according to the formula ratio; S2. Mixing and preparing wet materials: The core powder and the shell powder are fed into a mixer separately, and a binder is added for stirring and mixing to obtain wet core materials and wet shell materials respectively. S3. Core preparation: The wet core material is prepared into a core. S4. Core Granulation: The mother core is fed into a granulator and wet core material is added to allow the mother core to gradually grow to the standard size. S5. Screening: The granulated kernel particles are screened to remove particles larger than the preset diameter, so as to obtain kernel particles that meet the standard size. S6. Shell Coating: The screened kernel particles are fed into the granulator, and wet shell material is added to make the kernel particles uniformly coated with the shell layer and gradually grow to the target size. S7. Drying and sintering: The double-layer structure green body particles are dried, and the dried particles are sent to a rotary kiln for high-temperature calcination to obtain ceramsite support.

2. The method for preparing a magnesite-reinforced ceramsite proppant according to claim 1, characterized in that: The core powder comprises the following raw materials in parts by weight: 50-65 parts bauxite, 10-20 parts magnesite, 10-20 parts potassium feldspar, and 5-15 parts iron ore; the outer shell powder comprises the following raw materials in parts by weight: 70-85 parts bauxite, 15-25 parts magnesite, 1-5 parts potassium feldspar, and 1-5 parts iron ore.

3. A magnesite-reinforced ceramsite proppant preparation device, comprising a support frame (5), characterized in that: The support (5) is inclined and rotatably connected to a first granulation disc (2) and a second granulation disc (4). The second granulation disc (4) is located directly below the first granulation disc (2). Between the first granulation disc (2) and the second granulation disc (4), there is a vortex screen disc (3) that rotates synchronously with the first granulation disc (2). The vortex screen disc (3) has a plurality of screen holes (23) evenly opened. The inner side of the vortex screen disc (3) is provided with a discharge port (22). Between the vortex screen disc (3) and the second granulation disc (4), there is a collection disc (11) at a position corresponding to the discharge port (22). Above the first granulation disc (2) is a core forming device (1) fixedly connected to the support (5). The core forming device (1) includes a material cylinder (18). A rotating shaft (16) is rotatably connected to the inner side of the material cylinder (18). A spiral blade (17) is fixedly connected to the outer side of the rotating shaft (16). A plurality of extrusion ports (20) are opened at the discharge end of the material cylinder (18). A cutter (21) fixedly connected to the rotating shaft (16) is provided on the outer side of the extrusion port (20).

4. The equipment for preparing magnesite-reinforced ceramsite proppant according to claim 3, characterized in that: The bracket (5) is rotatably connected to a first rotating frame (7) driven by a first hydraulic cylinder (6). A first motor (12) is fixedly connected to the first rotating frame (7). The first granulation disc (2) and the vortex screen disc (3) are both rotatably connected to the first rotating frame (7) and driven by the first motor (12).

5. The equipment for preparing magnesite-reinforced ceramsite proppant according to claim 3, characterized in that: The collecting tray (11) is fixedly connected to the first rotating frame (7), and a guide groove (24) is connected to one side of the collecting tray (11).

6. The equipment for preparing magnesite-reinforced ceramsite proppant according to claim 3, characterized in that: The bracket (5) is rotatably connected to a second rotating frame (9) driven by a second hydraulic cylinder (10). A second motor (13) is fixedly connected to the second rotating frame (9). The second granulation disc (4) is rotatably connected to the second rotating frame (9) and driven by the second motor (13).

7. The equipment for preparing magnesite-reinforced ceramsite proppant according to claim 6, characterized in that: Scrapers (8) are provided on the inner sides of both the first granulation disc (2) and the second granulation disc (4).

8. The equipment for preparing magnesite-reinforced ceramsite proppant according to claim 3, characterized in that: The cross-section of the vortex sieve disc (3) is arc-shaped.

9. The equipment for preparing magnesite-reinforced ceramsite proppant according to claim 3, characterized in that: The discharge end of the material cylinder (18) is fixedly connected to a conical seat (19).

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