Brown coal dust mist spraying treatment equipment for closed coal yard

Abstract

The invention discloses lignite dust mist spraying treatment equipment for a closed coal yard, and relates to the technical field of dust mist spraying for the closed coal yard, the lignite dust mist spraying treatment equipment for the closed coal yard comprises a channel and a main spray head, the channel is provided with a differential pressure induction type spraying unit, and the differential pressure induction type spraying unit comprises a main spray head. According to the invention, the intensity and the coverage angle of the fog curtain can realize self-adaption and graded active mechanical angle expansion according to the size of the negative pressure in the coal yard, active adjustment can be realized without manual intervention, and finer and more water fog drops which are distributed more uniformly are generated along with the secondary atomization effect in the angle expansion process; the collision probability and the adsorption efficiency of water droplets and dust in unit volume are greatly increased, a formed mist curtain is more compact and uniform, the dust wrapped by negative pressure vortex can be effectively disturbed, blocked and soaked, the escape path of the dust is cut off, and the interception effect in complex vortex is remarkably improved.

Description

Technical Field

[0001] This invention relates to the field of dust mist spraying technology for enclosed coal yards, specifically to a dust mist spraying device for lignite in enclosed coal yards. Background Technology

[0002] Spray dust suppression is the mainstream technology for dust control during coal storage and transportation. It has been widely used and achieved certain results in open and semi-enclosed coal yards. However, for enclosed coal yards, the special ventilation and airflow environment makes traditional spray dust suppression technology difficult to adapt to the control needs of lignite dust. The specific problems are as follows: The presence of a specific negative pressure airflow field in enclosed coal yards provides the driving force for the escape of lignite dust. Enclosed coal yards require ventilation through a top negative pressure exhaust system to remove toxic and harmful gases such as methane produced during lignite oxidation. This creates a stable negative pressure environment of -50 to -200 Pa inside the coal yard. Meanwhile, the operation of belt conveyors in the transfer area and the falling of lignite from chutes cause severe disturbances to the surrounding air, creating localized turbulent airflow. When this localized airflow overlaps with the main negative pressure airflow created by the top exhaust system, it easily generates irregular eddies. Especially in the vehicle entrance and exit passage areas, the outside normal pressure air and the negative pressure air in the coal yard form strong convection, further aggravating the eddy effect and making the airflow trajectory within the passage complex and variable.

[0003] The physical properties of lignite dust make it extremely easy for it to be carried away and escape by negative pressure vortices. Most lignite dust particles are <10μm in diameter (some are 2~5μm). They are lightweight and have a bulk density of only 60%~70% of that of conventional coal dust. They are highly responsive to airflow and are easily carried by negative pressure vortices, eventually escaping to the outside world through channel gaps and ventilation openings.

[0004] The structural limitations of traditional spray dust suppression equipment result in low interception efficiency: The fog curtain formed by ordinary nozzles is essentially a non-dense barrier composed of a large number of discrete water droplets suspended in the air. Its dust interception mechanism relies on the collision and adsorption between water droplets and dust particles, causing the dust to become heavier and then naturally settle. This process is highly dependent on the density and stability of the fog curtain. However, traditional nozzles have two major drawbacks: First, the fog curtain parameters are fixed, with spray pressure, droplet size, and distribution density all being constant values. The resulting fog curtain has a constant "rigidity," and when the negative pressure increases, the high-speed airflow can easily break through the fog curtain, forming an escape channel. Second, the adjustment method is passive. Even if some nozzles have pressure regulation functions, they still require manual operation and cannot respond in real time to the dynamic fluctuations of negative pressure in the coal yard. When the negative pressure rises sharply, the fog curtain does not have time to strengthen, and fine dust has already escaped through the gaps. When the negative pressure decreases, the excessive number of droplets will cause water waste and surface water problems.

[0005] Based on this, the present invention designs a jet spray treatment device for lignite dust in enclosed coal yards to solve the above problems. Summary of the Invention

[0006] The purpose of this invention is to provide a mist spraying device for treating lignite dust in enclosed coal yards, so as to solve the problems mentioned in the background art.

[0007] To achieve the above objectives, the present invention provides the following technical solution: a mist spraying device for treating lignite dust in an enclosed coal yard, comprising a channel and a main nozzle, wherein a differential pressure sensing spraying unit is installed on the channel, and the differential pressure sensing spraying unit comprises: The cavity is located in the passageway and connects the inside and outside of the coal yard; An elastic diaphragm is located inside the cavity; The pipe is connected at its bottom to the main nozzle and is located inside the coal yard. The throttling orifice is conical and located inside the pipe. The adjusting rod has one end located inside the throttling orifice and matching the shape of the orifice, while the other end of the adjusting rod is disposed on an elastic diaphragm.

[0008] As a further aspect of the present invention, the main nozzle also includes a jet-assisted momentum implantation expansion unit; The jet-assisted momentum implantation expansion unit includes an auxiliary nozzle, a connecting pipe, and a pressure triggering unit. The auxiliary nozzle is sleeved on the main nozzle, and several nozzle holes are opened at the bottom of the auxiliary nozzle. The axis of the nozzle holes is inclined relative to the axis of the main nozzle. The connecting pipe is located between the auxiliary nozzle and the main pipe. The pressure triggering unit is used to connect the connecting pipe to the auxiliary nozzle after the pressure reaches the threshold.

[0009] As a further embodiment of the present invention, the spray hole includes an inner hole and an outer hole, and the inclination of the axes of the inner hole and the outer hole relative to the main nozzle gradually increases; The pressure triggering unit is used to connect the inner hole and the outer hole to the connecting pipe, respectively.

[0010] As a further embodiment of the present invention, the pressure triggering unit includes a baffle that is elastically slidably connected inside the connecting pipe. The baffle has a notch, and the connecting pipe has a flow channel one and a flow channel two. The flow channel one communicates with the inner hole, and the flow channel two communicates with the outer hole.

[0011] As a further embodiment of the present invention, a threaded rod is threadedly connected to the bottom of the connecting pipe, the bottom end of the threaded rod is located outside the connecting pipe, and a spring is provided between the top end of the threaded rod and the baffle.

[0012] As a further embodiment of the present invention, a fixing plate is provided on the inner wall of the cavity, and a connector is provided at the other end of the adjusting rod. The connector is located on the other side of the elastic diaphragm, and the connector is threadedly connected to the adjusting rod.

[0013] As a further embodiment of the present invention, a support frame is provided on the side wall of the channel, and the support frame is disposed on the pipe.

[0014] As a further embodiment of the present invention, the elastic diaphragm is made of fluorosilicone rubber.

[0015] Compared with the prior art, the beneficial effects of the present invention are: This invention enables the fog curtain's intensity and coverage angle to be adaptively and progressively expanded mechanically according to the magnitude of the negative pressure inside the coal yard. This active adjustment is achieved without human intervention. Furthermore, the secondary atomization effect accompanying the expansion process generates finer, more numerous, and more uniformly distributed water droplets, significantly increasing the collision probability and adsorption efficiency between water droplets and dust per unit volume. The resulting fog curtain is denser and more uniform, effectively disrupting, blocking, and wetting the dust carried by the negative pressure vortex, cutting off its escape path, and significantly improving the interception effect in complex vortices. Attached Figure Description

[0016] Figure 1 This is a schematic diagram of the overall structure of the present invention; Figure 2 This is a schematic diagram showing the connection relationship between the support frame and the channel sidewall of the present invention; Figure 3 This is a schematic diagram of the internal structure of the pipe and cavity of the present invention; Figure 4 This is a schematic diagram of the internal structure of the connecting pipe and the auxiliary nozzle of the present invention; Figure 5 This is a schematic diagram of the internal structure of the connecting pipe and the auxiliary nozzle of the present invention; Figure 6 This is a schematic diagram showing the spray angle of the mist cone under low, medium, and high pressure conditions according to the present invention; Figure 7 This is a schematic diagram showing the encounter between the droplets ejected from the main nozzle of the present invention and the jet streams ejected from the inner and outer holes; Figure 8 This is a schematic diagram showing the connection relationship between the fixing plate and the inner wall of the cavity in this invention.

[0017] The attached diagram lists the components represented by each number as follows: 1. Channel; 2. Main nozzle; 3. Cavity; 4. Elastic diaphragm; 5. Pipe; 6. Throttling orifice; 7. Adjusting rod; 8. Auxiliary nozzle; 9. Nozzle; 901. Inner hole; 902. Outer hole; 10. Connecting pipe; 1001. Flow channel one; 1002. Flow channel two; 11. Baffle; 12. Notch; 13. Threaded rod; 14. Spring; 15. Fixing plate; 16. Connecting piece; 17. Support frame. Detailed Implementation

[0018] Please see Figures 1-8 This invention provides a technical solution: a mist spraying device for treating lignite dust in a closed coal yard, comprising a channel 1 and a main nozzle 2. A differential pressure sensing spraying unit is installed on the channel 1. The differential pressure sensing spraying unit includes a cavity 3, an elastic diaphragm 4, a pipe 5, a throttling orifice 6, and an adjusting rod 7. The elastic diaphragm 4 divides the cavity 3 into two chambers, one near the inside of the coal yard and the other near the outside. The cavity 3 is located on the channel 1 and connects the inside and outside of the coal yard. The elastic diaphragm 4 is located inside the cavity 3. The bottom end of the pipe 5 is connected to the main nozzle 2 and is located inside the coal yard. The top end of the pipe 5 is provided with a water inlet end that communicates with an external water pipe. The throttling orifice 6 is conical and is located inside the pipe 5. One end of the adjusting rod 7 is located inside the throttling orifice 6 and matches the shape of the throttling orifice 6. The other end of the adjusting rod 7 is located on the elastic diaphragm 4.

[0019] like Figures 1-3 As shown: When the negative pressure in the coal yard increases, the elastic diaphragm 4 is indented into the coal yard by the pressure difference, which drives the regulating rod 7 to move inside the throttling orifice 6. The opening of the throttling orifice 6 increases, the pressure inside the pipeline 5 increases, and the flow velocity of the mist droplets sprayed from the main nozzle 2 increases, forming a denser mist curtain with higher kinetic energy to counteract the enhanced vortex airflow, prevent lignite dust from escaping from the gaps in the mist curtain, and improve the interception efficiency.

[0020] Conversely, when the negative pressure inside the coal yard weakens, the elastic diaphragm 4 rebounds, pulling the adjusting rod 7 back, reducing the opening of the throttle orifice 6, and the spray pressure automatically decreases to avoid over-spraying.

[0021] The main nozzle 2 also includes a jet-assisted momentum implantation expansion unit; The jet-assisted momentum implantation expansion unit includes an auxiliary nozzle 8, a connecting pipe 10, and a pressure triggering unit. The auxiliary nozzle 8 is sleeved on the main nozzle 2. Several nozzle holes 9 are opened at the bottom of the auxiliary nozzle 8. The axis of the nozzle holes 9 is inclined relative to the axis of the main nozzle 2. The connecting pipe 10 is located between the auxiliary nozzle 8 and the pipe 5. The distance between the main nozzle 2 and the nozzle holes 9 is sufficient to allow the droplet cloud generated by the main nozzle 2 to meet the fine water line that is inclinedly jetted from the nozzle holes 9 around the main nozzle 2 when it first leaves the main nozzle 2 and has not yet fully diffused. The pressure triggering unit is used to connect the connecting pipe 10 to the auxiliary nozzle 8 after the pressure reaches the threshold.

[0022] The nozzle 9 includes an inner hole 901 and an outer hole 902, and the inclination of the axes of the inner hole 901 and the outer hole 902 relative to the main nozzle 2 gradually increases; The pressure triggering unit is used to connect the inner hole 901 and the outer hole 902 to the connecting pipe 10, respectively.

[0023] The pressure triggering unit includes a baffle 11 that is elastically slidably connected inside the connecting pipe 10. The baffle 11 has a notch 12. The connecting pipe 10 has a flow channel 1001 and a flow channel 1002. The flow channel 1001 is connected to the inner hole 901, and the flow channel 1002 is connected to the outer hole 902.

[0024] like Figures 1-7 As shown: The working conditions for inner hole 901 and outer hole 902 are as follows: At low pressure (i.e., initial pressure), the opening of the throttle orifice 6 is fixed, the water pressure is fixed, and when the water flows from inside the pipe 5 into the connecting pipe 10, it is blocked by the baffle 11, which blocks the water flow and prevents the water flow from moving into the auxiliary nozzle 8, so that it does not work at low pressure.

[0025] At medium pressure, when the regulating rod 7 moves to the right inside the throttle port 6, the opening increases and the water pressure increases to the point that it pushes the baffle 11 down the inner wall of the connecting pipe 10 to the notch 12 and the flow channel 1001. At this time, the spring 14 is compressed, and the water flow inside the pipe 5 enters the auxiliary nozzle 8 after passing through the notch 12 and the flow channel 1001, and is ejected from the inclined inner hole 901 as an inclined fine water line.

[0026] Under high pressure, the opening of the throttle port 6 increases again, and the spring 14 is compressed again. At this time, the notch 12 is connected to the second flow channel 1002. The upper part of the cylindrical baffle 11 blocks the inlet of the first flow channel 1001. The water flow inside the connecting pipe 10 enters the auxiliary nozzle 8 through the second flow channel 1002 and is ejected from the outer hole 902.

[0027] When the negative pressure increases and the opening of the throttle orifice increases, the spray height rises, and the spray angle of the mist cone will decrease due to the high pressure (e.g., Figure 7 As shown, a, b, and c correspond to the spray angles of the mist cone at low, medium, and high pressures, respectively, where a > b > c. Spray blind zones may appear on both sides of channel 1 (the blind zones are as follows: ...). Figure 1 The area marked with a shaded region H is formed by the change of the jet line of the droplets from S to s, causing the fine dust of lignite to escape from the blind zone. Therefore, the spray angle of the mist cone needs to be increased when the pressure increases.

[0028] The specific process for jet-assisted momentum implantation into the expanding angle unit is as follows: Phase 1: High-pressure assisted jet generation and radial momentum implantation: When the negative pressure in the coal yard increases, the pressure inside the main pipeline 5 rises (inner hole 901 and outer hole 902 will be triggered separately under medium and high pressure conditions; here, we will not distinguish between high and low pressure conditions, but only describe it by the nozzle 9). After triggering the pressure triggering unit, the high-pressure water flows through the connecting pipe 10 into the annular auxiliary nozzle 8, and finally sprays out at extremely high speed from the circumferentially evenly distributed, inclined nozzles 9, forming a dense, thin high-energy water jet (the water jets of inner hole 901 and outer hole 902 are marked as S1 and S2 respectively in the figure, where S represents the droplets sprayed by the main nozzle 2); these jets form a preset angle with the central axis of the main nozzle 2 (e.g., the angle of inner hole 901 is 30°, and the angle of outer hole 902 is 45°). Furthermore, the velocity vector of each inclined jet can be decomposed into an axial component and a radial component, with the radial component pointing outwards from the mist cone. In the very near region where the mist cone of the main nozzle 2 just begins to diffuse (marked by the dashed box P in the figure, i.e., the contact area between S1, S2 and the mist droplets S), these high-energy water jets from all sides directly impact the edge of the central mist cone's mist droplet group from the side. Through direct fluid collision, the water jets efficiently and forcibly "implant" their enormous radial momentum into the mist droplets (S), giving them a strong, outward initial acceleration. This is the most fundamental "first driving force" for changing the trajectory of the mist droplet group and achieving the expansion angle.

[0029] Second stage: Formation of strong shear layer and secondary droplet fragmentation (dynamic enhancement) The high-energy water jet ejected from nozzle 9 has a velocity much higher than the average velocity of the droplets in the main mist cone, creating a huge velocity difference that generates a strong velocity shear layer in the convergence region. This shear layer is extremely unstable and can induce severe Kelvin-Helmholtz instability. Under this effect: The high-speed water jet itself is elongated, twisted, and broken into larger droplets, but the process releases energy (manifested as periodic vortexing and shearing at the shear layer interface). More importantly, the high shear force acts on the larger droplets in the main mist cone, producing a strong stretching and tearing effect, causing them to undergo secondary breakage, splitting into more and finer droplets. The fine droplets produced by secondary breakage have less inertia, can more efficiently absorb the radial momentum transferred by the jet, and their outward diffusion speed is significantly increased compared to unbroken droplets, further amplifying the widening effect. At the same time, the specific surface area of ​​the fine droplets increases and their inertia decreases, making them better able to follow the airflow in the subsequent flow and easier to diffuse and transport, laying the foundation for subsequent dust capture.

[0030] Phase 3: Composite Flow Field Reorganization and Aerodynamic Entrainment Diffusion (Stable Formation) The effects of the first two stages alter the local flow field structure near the main nozzle 2. The main atomized flow from the center mixes, collides, and exchanges momentum with the inclined high-energy jets (and their broken droplets) from all sides, jointly reorganizing and creating a completely new, highly turbulent gas-water two-phase mixed flow field. The overall momentum direction of this flow field is outward along the inclined direction of the nozzle 9, forming a strong expansion trend. The high-speed expansion of the composite flow field will entrain the surrounding air. The entrained airflow forms an "aerodynamic support layer" on the outside of the fog cone and further promotes the fog droplets to diffuse outward, forming a denser and stiffer fog curtain.

[0031] To ensure stable mechanical expansion of the fog curtain's spray angle when increased negative pressure leads to increased water pressure and causes a reduction in the fixed spray angle of the fog cone, and to improve the density and rigidity of the fog curtain when water pressure increases, thus ensuring effective dust collection.

[0032] Through the inner hole 901 and outer hole 902 with different inclinations, the system is triggered at medium and high pressure respectively (and can still be automatically triggered when transitioning from high to medium pressure). That is, at medium pressure (when the fog cone spray angle is reduced to a low degree), the slightly inclined inner hole 901 performs a first-stage expansion; at high pressure (when the fog cone spray angle is reduced to a high degree), the outer hole 902 performs a second-stage expansion. For example, when the pressure is constant, the initial radiation width of the droplet (S) is LS. The coverage width after the expansion of the angle through the inner hole 901 and the outer hole 902 will become LS1 and LS2 (LS < LS1 < LS2).

[0033] Furthermore, in actual use, the channel 1 does not need to be equipped with many nozzles. Only 1-2 main nozzles 2 and auxiliary nozzles 8 in this embodiment are required. This can avoid excessive overlap of the mist cones of multiple nozzles when the initial low pressure is low, which would cause a lot of water waste. In addition, there is no need for multiple matching water inlet pipes and mounting brackets when multiple nozzles are densely installed.

[0034] This invention enables the fog curtain's intensity and coverage angle to be adaptively and progressively expanded mechanically according to the magnitude of the negative pressure inside the coal yard. This active adjustment is achieved without human intervention. Furthermore, the secondary atomization effect accompanying the expansion process generates finer, more numerous, and more uniformly distributed water droplets, significantly increasing the collision probability and adsorption efficiency between water droplets and dust (especially <10μm lignite dust) per unit volume. The resulting fog curtain is denser and more uniform, effectively disrupting, blocking, and wetting the dust carried by the negative pressure vortex, cutting off its escape path, and significantly improving the interception effect in complex vortices.

[0035] As a further embodiment of the present invention, a threaded rod 13 is threadedly connected to the bottom of the inner tube 10, the bottom end of the threaded rod 13 is located outside the inner tube 10, and a spring 14 is provided between the top end of the threaded rod 13 and the baffle 11.

[0036] like Figure 4 and Figure 5 As shown: By rotating the threaded rod 13 inside the connecting pipe 5, the spring 14 is pre-compressed or pre-relaxed, thereby adjusting the force of the baffle 11 in unidirectionally blocking the water flow.

[0037] As a further embodiment of the present invention, a fixing piece 15 is provided on the inner wall of the cavity 3, and a connector 16 is provided at the other end of the adjusting rod 7. The connector 16 is located on the other side of the elastic diaphragm 4, and the connector 16 is threadedly connected to the adjusting rod 7.

[0038] like Figure 3 and Figure 8 As shown: The fixing plate 15 is detachably connected to the inner wall of the cavity 3 by bolts (marked as A1 in the figure), and the elastic diaphragm 4 is clamped between the cavity 3 and the fixing plate 15. The connecting piece 16 passes through the center of the elastic diaphragm 4 and is threadedly connected to the adjusting rod 7, which facilitates the replacement of the elastic diaphragm 4.

[0039] A support frame 17 is provided on the side wall of channel 1, and the support frame 17 is installed on pipe 5.

[0040] like Figure 2 and Figure 3 As shown: The pipe 5 is supported by the support frame 17, which can be threaded for easy disassembly.

[0041] The elastic diaphragm 4 is made of fluorosilicone rubber (FVMQ), which is suitable for extreme temperatures of -20℃ to 60℃ in winter and summer.

Claims

1. A lignite dust fogging treatment equipment for closed coal yard, comprising a channel (1) and a main nozzle (2), characterized in that, The channel (1) is provided with a differential pressure sensing type spraying unit, which comprises: The cavity (3) is opened on the channel (1) and is connected with the inside and outside of the coal yard. The elastic diaphragm (4) is located inside the cavity (3). The pipeline (5) is connected with the main nozzle (2) at the bottom end and is located inside the coal yard. The throttle (6) is tapered and is opened inside the pipeline (5). The adjusting rod (7) is located inside the throttle (6) at one end and is matched with the shape of the throttle (6), and the other end of the adjusting rod (7) is arranged on the elastic diaphragm (4).

2. The lignite dust misting device for closed coal yard according to claim 1, characterized in that: The main nozzle (2) further comprises a jet auxiliary momentum implantation angle expansion unit. The spacing between the main nozzle (2) and the jet auxiliary momentum implantation angle expansion unit satisfies that the mist droplet cloud generated by the main nozzle (2) meets the water mist line obliquely sprayed by the jet auxiliary momentum implantation angle expansion unit when the mist droplet cloud leaves the main nozzle (2) and has not been fully dispersed, so that the angle of the mist droplet cloud is expanded by the momentum implantation of the jet auxiliary momentum implantation angle expansion unit. The pressure trigger unit is used to make the communication pipe (10) and the auxiliary spray pipe (8) communicate when the pressure reaches a threshold value.

3. The lignite dust misting device for closed coal yard according to claim 2, characterized in that: The jet auxiliary momentum implantation angle expansion unit comprises an auxiliary spray pipe (8), a communication pipe (10) and a pressure trigger unit, the auxiliary spray pipe (8) is sleeved on the main nozzle (2), the bottom of the auxiliary spray pipe (8) is provided with a plurality of spray holes (9), the axis of the spray hole (9) is arranged obliquely relative to the axis of the main nozzle (2), and the communication pipe (10) is arranged between the auxiliary spray pipe (8) and the pipeline (5).

4. The lignite dust misting device for closed coal yard according to claim 3, characterized in that: The spray hole (9) comprises an inner hole (901) and an outer hole (902). The pressure trigger unit is used to make the inner hole (901) and the outer hole (902) respectively communicate with the communication pipe (10).

5. The lignite dust misting device for closed coal yard according to claim 4, characterized in that: The inclination of the axes of the inner hole (901) and the outer hole (902) relative to the main nozzle (2) gradually increases.

6. The lignite dust misting device for closed coal yard of claim 5, characterized in that: The pressure trigger unit comprises a baffle (11) elastically and slidably connected inside the communication pipe (10), the baffle (11) is provided with a notch (12), the communication pipe (10) is provided with a flow channel one (1001) and a flow channel two (1002), the flow channel one (1001) communicates with the inner hole (901), and the flow channel two (1002) communicates with the outer hole (902).

7. The lignite dust misting device for closed coal yard of claim 6, characterized in that: The inner bottom of the communication pipe (10) is threadedly connected with a threaded rod (13), the bottom end of the threaded rod (13) is located outside the communication pipe (10), and a spring (14) is arranged between the top end of the threaded rod (13) and the baffle (11).

8. The lignite dust misting device for closed coal yard of claim 1, characterized in that: The inner wall of the cavity (3) is provided with a fixing piece (15), the other end of the adjusting rod (7) is provided with a connecting piece (16), the connecting piece (16) is located on the other side of the elastic diaphragm (4), and the connecting piece (16) is threadedly connected with the adjusting rod (7).

9. The lignite dust misting device for closed coal yard of claim 1, characterized in that: The side wall of the channel (1) is provided with a support frame (17), and the support frame (17) is arranged on the pipeline (5).

10. The lignite dust misting management equipment for closed coal yard according to claim 1, characterized in that: The elastic diaphragm (4) is made of fluorosilicone rubber.

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