A small coal powder feeder with adjustable air and powder for experimental use

Abstract

The present invention relates to the technical field of powder feeders, and specifically to a small-sized coal powder feeder with adjustable wind and powder for experiments, comprising a rotating motor and a screw feeder, wherein a screw feeder threaded rod is installed for rotation inside the screw feeder, and the output end of the rotating motor is fixedly connected to one end of the screw feeder threaded rod; a heating component, wherein the heating component is arranged on the outer surface of the screw feeder, and the heating component is used to heat the material inside the screw feeder; and a primary air duct, wherein the primary air duct is arranged below one side of the screw feeder. Compared with the prior art, the present application improves the stability and efficiency of coal powder combustion through the primary air duct, and the overall design takes into account the requirements of anti-blocking, anti-wear and efficient combustion, which significantly improves the safety of equipment operation and the reliability of combustion experiments.

Description

Technical Field

[0001] The invention relates to the technical field of powder feeders, in particular to a small-sized coal powder feeder with adjustable wind and powder for experiments. Background Art

[0002] Building a small pulverized coal flame in the laboratory to study the combustion characteristics of pulverized coal is an important method in the field of combustion science. This method can systematically study the combustion behavior, reaction kinetics and flame characteristics of pulverized coal in a controllable environment, providing key data for optimizing combustion efficiency and reducing pollutant emissions. In this process, the performance of the pulverized coal feeding device plays a vital role. Its stability and accuracy directly affect the uniformity of pulverized coal supply and the controllability of the flow rate, which in turn has a significant impact on the formation, propagation and stability of the pulverized coal flame.

[0003] In the prior art, the existing large-scale pulverized coal feeding devices have a series of drawbacks. For example, "Diagnosis of pulverized coal feeding pipeline blockage fault based on neural network", "Power Generation Equipment", 2007NO.4 pointed out that the existing furnace powder feeding device is a Y-shaped pipe fitting, and the primary air and pulverized coal are fed in from their respective entrances. Since the pulverized coal falls completely by gravity and mixes with the primary air at the Y-shaped interface, the pulverized coal falling pipe fitting is directly connected to the furnace, which is very sensitive to the pressure change of the furnace and the fluctuation of the pulverized coal feeding amount. When the pulverized coal feeding amount suddenly increases or the internal pressure of the furnace suddenly increases, the pulverized coal is easily blocked at the Y-shaped interface, which has a very bad impact on the normal operation of the thermal equipment. Another example is "The influence of the combined primary air duct on the operation of the boiler". "Journal of Power Engineering", 2018, 38 (9) pointed out that when the boiler is running at low load, the pulverized coal concentration decreases and ignition is difficult. Increasing the pulverized coal concentration in the primary air flow and maintaining the primary air pulverized coal concentration at the optimal pulverized coal concentration that is conducive to stable ignition can improve ignition stability at low loads. However, the specific implementation of this technology is very difficult because when the boiler is running at low load, the amount of coal required for boiler combustion decreases with the reduction of the unit load. However, since the flow area of ​​the boiler's powder delivery pipeline cannot be adjusted, in order to prevent the pulverized coal from being deposited due to the low flow rate of the pulverized coal delivery airflow, a higher primary air volume is required to maintain the flow rate of the pulverized coal delivery airflow within the specified range. This results in a low pulverized coal concentration in the pulverized coal delivery airflow, which is not conducive to the stable ignition and combustion of pulverized coal. When running at low load, there is a contradiction between maintaining the optimal pulverized coal concentration and preventing pulverized coal deposition. The current choice is to abandon the optimal pulverized coal concentration and ensure the safety of pulverized coal transportation, which is bound to have an adverse effect on the stable combustion of pulverized coal.

[0004] Therefore, the present application discloses a small-sized coal powder feeder with adjustable wind and powder for experimental use, which can achieve accurate and stable coal powder supply. Summary of the invention

[0005] In view of this, the purpose of the present invention is to propose a small-scale coal powder feeder with adjustable wind and powder for experimental use, so as to solve the problems of coal powder blockage, unstable transportation and difficulty in balancing the prevention of coal powder deposition and maintaining the optimal coal powder concentration during low-load operation in existing large-scale coal powder feeding devices, which affect combustion stability and equipment operation.

[0006] Based on the above purpose, the present invention provides a small-sized coal powder feeder with adjustable wind and powder for experiment, comprising a rotating motor and a screw feeder, wherein a screw feeder threaded rod is rotatably installed inside the screw feeder, and the output end of the rotating motor is fixedly connected to one end of the screw feeder threaded rod, a screw feeder coal powder inlet is arranged above one side of the screw feeder, and a screw feeder coal powder outlet is arranged below one side of the screw feeder;

[0007] A heating component, the heating component is arranged on the outer surface of the screw feeder, and the heating component is used to heat the material inside the screw feeder;

[0008] A primary air duct, the primary air duct is arranged below one side of the screw feeder, a primary air duct coal powder inlet is arranged in the middle of the primary air duct to match the coal powder outlet of the screw feeder, and the primary air duct is used to transport a mixture of air and coal powder;

[0009] A mixing component is arranged at the inner bottom of the screw feeder, and is used for enhancing the mixing of the material inside the screw feeder during the extrusion process.

[0010] Preferably, the heating assembly includes a heating jacket sleeved on the outer surface of the screw feeder, a plurality of hot air blowers are arranged at the bottom of the heating jacket, an air inlet channel for heating the incoming air is arranged at the bottom of the plurality of hot air blowers, the heating jacket is a double-layer hollow arrangement, and the hot air blowers are connected to the heating jacket.

[0011] Preferably, both inner side walls of the screw feeder are provided with protrusions matched with the threaded rods of the screw feeder.

[0012] Preferably, the mixing assembly comprises a plurality of mixing blocks fixedly mounted on the bottom of the screw feeder, and two ends of the mixing assembly are respectively abutted against the protrusions on both sides of the screw feeder.

[0013] Preferably, a plurality of mixing grooves are equidistantly provided on the upper surface of the mixing block, a plurality of inclined reflux grooves are staggered on both sides of the mixing groove, one end of the reflux groove is connected to the mixing groove, and the other end is arranged in a concave semicircular shape to achieve a reflux effect.

[0014] Preferably, the reflux groove is provided with a matching reflux column inside, one end of the reflux column is in a slope shape and parallel to the mixing groove, and the other end is arranged in a semicircular shape protruding outward.

[0015] Preferably, the primary air duct includes a primary air duct thick section a, a primary air duct thin section and a primary air duct thick section b, the two ends of the primary air duct thin section are respectively fixedly connected to the primary air duct thick section a and the primary air duct thick section b, the diameters of the primary air duct thick section a and the primary air duct thick section b are twice the diameter of the primary air duct thin section, a primary air duct air inlet is provided on one side of the primary air duct thick section a, a primary air duct outlet is provided on one side of the primary air duct thick section b, an air inlet fan for air intake is provided on one side of the primary air duct inlet, and the primary air duct outlet is aligned with the external furnace.

[0016] Preferably, the diameter of the connection between the thick section a of the primary air duct and the thin section of the primary air duct is gradually reduced, thereby forming a Venturi effect, improving the mixing efficiency of coal powder and wind, and preventing coal powder from depositing.

[0017] Preferably, the diameter of the coal powder inlet of the primary air duct is smaller than the primary air duct thin section, and a vibration motor is provided on one side of the primary air duct thin section.

[0018] Preferably, a motor frequency converter for controlling the rotating motor is disposed on one side of the rotating motor, and a fan frequency converter for controlling the fan is also disposed on one side of the fan.

[0019] Beneficial effects of the present invention:

[0020] 1. This kind of experimental small-scale coal powder feeder with adjustable air and powder is equipped with a primary air duct. The Venturi tube structure effectively improves the mixing efficiency of coal powder and air, ensures that coal powder does not settle or get blocked during transportation, and thus improves the stability and combustion efficiency of the powder supply system. The thin section of the primary air duct is located between the two thick tubes, so that the airflow is accelerated in the thin section to form a suction effect, enhance the mixing degree of coal powder and air, prevent coal powder from accumulating on the inner wall of the pipeline, and reduce the frequency of equipment maintenance. The coal powder inlet of the primary air duct is designed to be smaller than the diameter of the thin section, and the connection adopts a rounded transition to avoid the formation of dead zones by sharp corners, effectively prevent coal powder from accumulating or settling at the interface, and improve the continuity and reliability of transportation. In addition, the screw feeder outlet The height difference between the inlet and the coal powder inlet of the primary air duct combined with the effect of gravity allows the coal powder to fall smoothly into the airflow and quickly enter the primary air duct under the suction of high-speed airflow, avoiding coal powder accumulation and blockage at the outlet. The installation of a vibration motor further reduces the risk of deposition at the coal powder inlet. Vibration can cause the coal powder to loosen and enter the airflow smoothly, reducing the risk of blockage from the source. The diameter of the thick section b is enlarged to reduce the wind speed of the mixed gas powder before it is transported to the furnace, ensuring uniform distribution of coal powder and avoiding wear and deviation of the furnace or pipe wall by high-speed airflow, thereby improving the stability and efficiency of coal powder combustion. The overall design takes into account the needs of anti-blocking, anti-wear and efficient combustion, significantly improving the safety of equipment operation and the reliability of combustion experiments.

[0021] 2. This type of experimental small-scale coal powder feeder with adjustable wind and powder is equipped with a mixing component, and the mixing trough and the reflux trough are staggered to form a multi-stage mixing path, so that the coal powder can continuously change its flow direction during the spiral propulsion process, prevent particle stratification or agglomeration, and ensure uniform supply of coal powder. The reflux column set in the reflux trough further enhances the turbulence and reflux effects, promotes repeated circulation of coal powder, achieves deep mixing, and reduces the problem of unstable transportation caused by the different sizes of coal powder particles. The concave semicircular structure of the reflux trough effectively prevents coal powder from depositing, avoids pipeline blockage, and improves the continuity and reliability of equipment operation. The overall design ensures that the coal powder always maintains a good flow state during the transportation process, which not only improves the accuracy of the powder supply system, but also reduces the maintenance frequency and blockage risk, providing a more stable and efficient powder supply guarantee for coal powder combustion experiments.

[0022] 3. This kind of experimental small pulverized coal feeder with adjustable wind and powder is equipped with a heating component. The heating jacket adopts a double-layer hollow structure. The hot air blower transports hot air into the cavity through the heated air inlet channel, so that the heat is evenly distributed inside the cavity, thereby comprehensively heating the outer surface of the screw feeder to avoid local overheating or uneven heating, improve heating efficiency, and keep the pulverized coal in good fluidity during transportation to prevent moisture or agglomeration. Multiple hot air blowers are distributed at the bottom of the heating jacket to form a multi-point heating mode. Even if a hot air blower fails, it will not affect the overall heating effect, thereby improving system reliability and ensuring the continuity and stability of the experimental process. BRIEF DESCRIPTION OF THE DRAWINGS

[0023] In order to more clearly illustrate the technical solutions in the present invention or the prior art, the drawings required for use in the embodiments or the description of the prior art will be briefly introduced below. Obviously, the drawings in the following description are only for the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying creative work.

[0024] Figure 1 This is a schematic diagram of the three-dimensional structure of the present invention from a first viewing angle;

[0025] Figure 2 It is a schematic diagram of the three-dimensional structure of the present invention from a second viewing angle;

[0026] Figure 3 It is a structural schematic diagram of the spiral feeder of the present invention;

[0027] Figure 4 This is a schematic diagram of the heating assembly structure of the present invention;

[0028] Figure 5 This is a schematic diagram of the structure of the threaded rod of the screw feeder of the present invention;

[0029] Figure 6 It is a schematic diagram of the structure of the mixing assembly of the present invention;

[0030] Figure 7 It is a schematic diagram of the local structure of the mixing assembly of the present invention;

[0031] Figure 8 This is a schematic diagram of the primary air duct structure of the present invention.

[0032] The markings in the figure are:

[0033] 1. Rotating motor; 2. Motor inverter; 3. Screw feeder; 4. Coal powder inlet of screw feeder; 5. Coal powder outlet of screw feeder; 6. Heating jacket; 7. Hot air blower; 8. Air inlet channel; 9. Air inlet fan; 10. Primary air duct; 11. Vibrating motor; 12. Coal powder inlet of primary air duct; 13. Air inlet of primary air duct; 14. Coarse section a of primary air duct; 15. Thin section of primary air duct; 16. Coarse section b of primary air duct; 17. Primary air duct outlet; 18. Threaded rod of screw feeder; 19. Bump; 20. Mixing block; 21. Mixing trough; 22. Reflux trough; 23. Reflux column. DETAILED DESCRIPTION

[0034] In order to make the objectives, technical solutions and advantages of the present invention more clearly understood, the present invention is further described in detail below in conjunction with specific embodiments.

[0035] It should be noted that, unless otherwise defined, the technical terms or scientific terms used in the present invention should be understood by people with ordinary skills in the field to which the present invention belongs. The "first", "second" and similar words used in the present invention do not indicate any order, quantity or importance, but are only used to distinguish different components. "Include" or "comprise" and similar words mean that the elements or objects appearing before the word include the elements or objects listed after the word and their equivalents, without excluding other elements or objects. "Connect" or "connected" and similar words are not limited to physical or mechanical connections, but may include electrical connections, whether direct or indirect. "Up", "down", "left", "right" and the like are only used to indicate relative positional relationships. When the absolute position of the described object changes, the relative positional relationship may also change accordingly.

[0036] like Figures 1 to 8 As shown, a small-scale coal powder feeder with adjustable wind and powder for experiment comprises a rotating motor 1 and a screw feeder 3, wherein a screw feeder threaded rod 18 is rotatably installed inside the screw feeder 3, and the output end of the rotating motor 1 is fixedly connected to one end of the screw feeder threaded rod 18, a screw feeder coal powder inlet 4 is arranged above one side of the screw feeder 3, and a screw feeder coal powder outlet 5 is arranged below one side of the screw feeder 3; a heating component, the heating component is arranged on the outer surface of the screw feeder 3, and the heating component is used to heat the material inside the screw feeder 3; a primary air duct 10, the primary air duct 10 is arranged below one side of the screw feeder 3, a primary air duct coal powder inlet 12 is arranged in the middle of the primary air duct 10 and is adapted to the screw feeder coal powder outlet 5, and the primary air duct 10 is used to convey a mixture of air and coal powder; a mixing component, the mixing component is arranged at the inner bottom of the screw feeder 3, and the mixing component is used to enhance the mixing of the material inside the screw feeder 3 during the extrusion process;

[0037] The pulverized coal is added to the screw feeder 3 through the pulverized coal inlet of the screw feeder 3, and the rotating motor 1 drives the screw feeder 3 threaded rod to rotate, and gradually pushes the pulverized coal to the pulverized coal outlet. During the pushing process, the pulverized coal is heated by the internal heating component of the screw feeder 3 to prevent it from getting damp and agglomerating. At the same time, the mixing component further stirs and enhances the uniformity of the pulverized coal. The pulverized coal enters the primary air duct 10 through the pulverized coal outlet of the screw feeder 3, and is fully mixed with the air under the action of the high-speed airflow provided by the fan and transported to the furnace to complete the pulverizing and combustion-supporting process. The heating component performs external heating on the screw feeder 3 to prevent the pulverized coal from getting damp and agglomerating due to humidity or temperature changes during the transportation process, thereby maintaining the fluidity and transportation stability of the pulverized coal, avoiding the deposition of pulverized coal inside the feeder, reducing the frequency of cleaning and maintenance, and improving the experimental efficiency. A primary air duct 10 is arranged below the screw feeder 3 to achieve preliminary mixing of pulverized coal and air during the transportation process, improve the transportation efficiency, and prevent the pulverized coal from being deposited or blocked in the pipeline. After the air and pulverized coal are mixed, the pulverized coal is more evenly distributed in the furnace, which is conducive to the stability and consistency of combustion.

[0038] like Figures 1 to 4 As shown, the heating assembly includes a heating jacket 6 sleeved on the outer surface of the screw feeder 3, a plurality of hot air blowers 7 are arranged at the bottom of the heating jacket 6, and an air inlet channel 8 for heating the incoming air is arranged at the bottom of the plurality of hot air blowers 7, the heating jacket 6 is a double-layer hollow arrangement, and the hot air blowers 7 are connected to the heating jacket 6;

[0039] The heating jacket 6 adopts a double-layer hollow structure. The hot air blower 7 delivers hot air into the cavity through the heated air inlet channel 8, so that the heat is evenly distributed inside the cavity, thereby comprehensively heating the outer surface of the screw feeder 3, avoiding local overheating or uneven heating, improving the heating efficiency, and keeping the coal powder in good fluidity during transportation to prevent moisture or agglomeration. Multiple hot air blowers 7 are distributed at the bottom of the heating jacket 6 to form a multi-point heating mode. Even if a hot air blower 7 fails, it will not affect the overall heating effect, thereby improving the reliability of the system and ensuring the continuous and stable experimental process. The double-layer hollow structure forms a heat insulation layer to reduce heat spillover, improve heating efficiency and reduce energy consumption. The hot air blower 7 directly delivers heated air into the cavity to reduce heat transfer loss and achieve energy saving and consumption reduction.

[0040] Both inner side walls of the screw feeder 3 are provided with protrusions 19 adapted to the screw feeder threaded rod 18;

[0041] The protrusion 19 is adapted to the threaded rod of the screw feeder 3, and plays a limiting and guiding role, ensuring that the threaded rod runs stably during rotation, avoiding unstable coal powder supply due to deviation or shaking. The threaded rod and the protrusion 19 are closely matched to reduce resistance and energy loss during transportation, increase the coal powder propulsion speed, make the powder supply more continuous and stable, and avoid powder supply interruption or jamming.

[0042] like Figure 1 , Figure 3 , Figure 6 As shown, the mixing assembly includes a plurality of mixing blocks 20 fixedly mounted on the bottom of the screw feeder 3, and the two ends of the mixing assembly are respectively abutted against the protrusions 19 on both sides of the screw feeder 3, and a plurality of mixing grooves 21 are equidistantly provided on the upper surface of the mixing block 20, and a plurality of reflux grooves 22 are staggeredly provided on both sides of the mixing groove 21 in an inclined shape, one end of the reflux groove 22 is connected to the mixing groove 21, and the other end of the reflux groove 22 is set to be a concave semicircle to achieve a reflux effect, and a matching reflux column 23 is set inside the reflux groove 22, one end of the reflux column 23 is in an inclined shape and parallel to the mixing groove 21, and the other end of the reflux column 23 is set to be a semicircle protruding outward;

[0043] The coal powder enters the mixing assembly through the screw feeder 3. As the threaded rod of the screw feeder 3 rotates, the coal powder is pushed into the mixing groove 21 of the mixing block 20. During the spiral advancement process, the coal powder continuously enters the reflux groove 22 and generates reflux and disturbance under the action of the reflux column 23. The coal powder particles are repeatedly interlaced and mixed. At the same time, the concave semicircular structure of the reflux groove 22 further guides the coal powder to reflux to prevent sedimentation and achieve uniform transportation. The mixing groove 21 and the reflux groove 22 set on the mixing block 20 form a multi-stage mixing path, so that the coal powder changes its flow direction many times during the advancement process. Through the reflux and disturbance effect, the coal powder particles are prevented from being stratified or agglomerated, ensuring uniform and consistent coal powder supply.

[0044] like Figure 1 , Figure 2 , Figure 8 As shown, the primary air duct 10 includes a primary air duct thick section a14, a primary air duct thin section 15 and a primary air duct thick section b16. The two ends of the primary air duct thin section 15 are fixedly connected to the primary air duct thick section a14 and the primary air duct thick section b16 respectively. The diameters of the primary air duct thick section a14 and the primary air duct thick section b16 are twice the diameter of the primary air duct thin section 15. A primary air duct air inlet 13 is provided on one side of the primary air duct thick section a14, and a primary air duct outlet 17 is provided on one side of the primary air duct thick section b16. A blower 9 for air intake is arranged on one side of 13, a primary air duct outlet 17 is aligned with the external furnace, the diameter of the connection between the primary air duct thick section a14 and the primary air duct thin section 15 is gradually reduced, thereby forming a Venturi effect, improving the mixing efficiency of coal powder and wind, and preventing coal powder from depositing, the diameter of the primary air duct coal powder inlet 12 is smaller than the diameter of the primary air duct thin section 15, the connection between the primary air duct coal powder inlet 12 and the primary air duct thin section 15 is rounded, and a vibration motor 11 is arranged on one side of the primary air duct coal powder inlet 12;

[0045] The pulverized coal enters the screw feeder 3 through the pulverized coal inlet of the feeder, and is transported to the outlet of the screw feeder 3 under the push of the spiral structure. The pulverized coal falls into the pulverized coal inlet 12 of the primary air duct from the outlet of the screw feeder 3 under the action of gravity; the fan blows air in from the air inlet of the primary air duct 10, and the air flow passes through the primary air duct thick section a14, the primary air duct thin section 15 and the primary air duct thick section b16 in sequence. The wind speed increases when flowing through the thin section, resulting in a suction effect, so that the pulverized coal and air are quickly mixed, and the pulverized coal is prevented from being deposited in the primary air duct 10; the mixed gas and powder continue to flow along the pipeline to the primary air duct thick section b16, and the wind speed decreases as the pipe diameter increases, and finally is evenly blown into the external furnace from the primary air duct outlet 17 to realize the pulverized coal combustion process, wherein the primary air duct thin section 15 is arranged between the two thick pipes to form a Venturi tube structure. When the air flows through the primary air duct thin section 15, the pipe diameter is reduced, resulting in an increase in wind speed, which produces a strong suction effect The pulverized coal and air are mixed quickly and fully, the uniformity of gas-powder mixing is improved, and the pulverized coal is prevented from settling or flowing poorly. The diameter of the pulverized coal inlet 12 of the primary air duct is smaller than the diameter of the thin section, and the connection is rounded, which eliminates the dead zone of the sharp corner, reduces the risk of pulverized coal accumulating at the interface, and improves the transportation stability. The suction effect of the high-speed airflow can also make the pulverized coal fall smoothly into the primary air duct 10, prevent the accumulation of pulverized coal at the outlet of the screw feeder 3, and avoid the blockage of the outlet. A vibration motor 11 is installed outside the pulverized coal inlet 12 of the primary air duct to prevent the accumulation of pulverized coal at the inlet through vibration, which helps the pulverized coal fall smoothly into the airflow, further reducing the risk of blockage and deposition. The diameter of the thick section b16 of the primary air duct is enlarged, and the wind speed is slowed down, so that the pulverized coal and air mixture is smoothly transported to the furnace, avoiding the wear or deflection caused by the pulverized coal hitting the pipe wall or the furnace due to the excessive wind speed, ensuring the uniform distribution of pulverized coal and improving the combustion efficiency.

[0046] A motor frequency converter 2 for controlling the rotating motor 1 is provided on one side of the rotating motor 1, and a fan frequency converter for controlling the fan 9 is also provided on one side of the fan 9;

[0047] The motor frequency converter is used to control the speed of the rotating motor 1 of the screw feeder 3. It can dynamically adjust the powder supply according to the experimental requirements to ensure the continuity and accuracy of the coal powder supply and avoid unstable combustion caused by excessive or insufficient powder supply. The fan frequency converter controls the air volume of the air inlet fan 9 to match the flow rate of the primary air with the coal powder supply, maintain a reasonable gas-powder ratio, ensure that the coal powder is fully burned in the furnace, and effectively avoid incomplete combustion or flameout caused by excessive or thin coal powder.

[0048] A person skilled in the art should understand that the discussion of any of the above embodiments is merely illustrative and is not intended to imply that the scope of the present invention (including the claims) is limited to these examples. Under the concept of the present invention, the technical features in the above embodiments or different embodiments may be combined, the steps may be implemented in any order, and there are many other variations of the different aspects of the present invention as described above, which are not provided in detail for the sake of simplicity.

[0049] The present invention is intended to cover all such substitutions, modifications and variations that fall within the broad scope of the appended claims. Therefore, any omissions, modifications, equivalent substitutions, improvements, etc. made within the spirit and principles of the present invention should be included in the scope of protection of the present invention.

Claims

1. A small coal powder feeder with adjustable air and powder for experimental use, characterized in that: include: A rotating motor (1) and a screw feeder (3), wherein a screw feeder threaded rod (18) is rotatably mounted inside the screw feeder (3), an output end of the rotating motor (1) is fixedly connected to one end of the screw feeder threaded rod (18), a screw feeder coal powder inlet (4) is provided above one side of the screw feeder (3), and a screw feeder coal powder outlet (5) is provided below one side of the screw feeder (3); A heating component, the heating component is arranged on the outer surface of the screw feeder (3), the heating component is used to heat the material inside the screw feeder (3), the heating component comprises a heating sleeve (6) sleeved on the outer surface of the screw feeder (3), a plurality of hot air blowers (7) are arranged at the bottom of the heating sleeve (6), and an air inlet channel (8) for heating the incoming air is arranged at the bottom of the plurality of hot air blowers (7), the heating sleeve (6) is a double-layer hollow arrangement, the hot air blowers (7) are connected to the heating sleeve (6), and both side walls inside the screw feeder (3) are provided with protrusions (19) adapted to the screw feeder threaded rod (18); a primary air duct (10), the primary air duct (10) being arranged below one side of the screw feeder (3), a primary air duct coal powder inlet (12) being arranged in the middle of the primary air duct (10) and being matched with the coal powder outlet (5) of the screw feeder, the primary air duct (10) being used for conveying a mixture of air and coal powder; A mixing component, the mixing component is arranged at the bottom of the screw feeder (3), the mixing component is used to enhance the mixing of the material inside the screw feeder (3) during the extrusion process, the mixing component comprises a plurality of mixing blocks (20) fixedly mounted at the bottom of the screw feeder (3), and the two ends of the mixing component are respectively abutted against the protrusions (19) on both sides of the screw feeder (3), and the upper surface of the mixing block (20) is provided with a plurality of mixing grooves at equal intervals. (21), a plurality of inclined reflux grooves (22) are staggered on both sides of the mixing groove (21), one end of the reflux groove (22) is connected to the mixing groove (21), and the other end of the reflux groove (22) is arranged in a concave semicircular shape to achieve a reflux effect, and a matching reflux column (23) is arranged inside the reflux groove (22), one end of the reflux column (23) is in an inclined shape and parallel to the mixing groove (21), and the other end of the reflux column (23) is arranged in an outwardly protruding semicircular shape.

2. The small-sized coal powder feeder with adjustable air and powder for experiment according to claim 1 is characterized in that: The primary air duct (10) comprises a primary air duct thick section a (14), a primary air duct thin section (15) and a primary air duct thick section b (16); two ends of the primary air duct thin section (15) are respectively fixedly connected to the primary air duct thick section a (14) and the primary air duct thick section b (16); the diameters of the primary air duct thick section a (14) and the primary air duct thick section b (16) are twice the diameter of the primary air duct thin section (15); a primary air duct air inlet (13) is provided on one side of the primary air duct thick section a (14); a primary air duct outlet (17) is provided on one side of the primary air duct thick section b (16); an air inlet fan (9) for air intake is provided on one side of the primary air duct air inlet (13); and the primary air duct outlet (17) is aligned with an external furnace.

3. The small-sized coal powder feeder with adjustable air and powder for experiment according to claim 2 is characterized in that: The diameter of the connection between the thick section a (14) of the primary air duct and the thin section (15) of the primary air duct is gradually reduced, thereby forming a Venturi effect, improving the mixing efficiency of coal powder and air, and preventing coal powder from depositing.

4. The small-sized coal powder feeder with adjustable air and powder for experiment according to claim 3 is characterized in that: The diameter of the primary air duct coal powder inlet (12) is smaller than the diameter of the primary air duct thin section (15); the connection between the primary air duct coal powder inlet (12) and the primary air duct thin section (15) is rounded; and a vibration motor (11) is provided on one side of the primary air duct coal powder inlet (12).

5. The small-sized coal powder feeder with adjustable air and powder for experiment according to claim 4 is characterized in that: A motor frequency converter (2) for controlling the rotating motor (1) is provided on one side of the rotating motor (1), and a fan frequency converter for controlling the fan (9) is also provided on one side of the fan (9).

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