Coal gangue slurry preparation and conveying system and method for goaf filling

Abstract

The invention discloses a coal gangue slurry preparation and conveying system and method for goaf filling. The coal gangue slurry preparation and conveying system comprises a material crushing system and a material conveying system, wherein the material crushing system comprises a storage bin, a vibrating feeder, a multi-stage crushing system, a vibrating screen and a surge bin; a storage bin is arranged in front of the vibrating feeder, and a multi-stage crushing system is arranged behind the vibrating feeder; the multi-stage crushing system comprises a plurality of crushing device systems, materials are treated by a first crushing device system and then enter a vibrating screen to be screened, qualified coal gangue powder enters a surge bin, and unqualified coal gangue powder enters a second crushing device system to be crushed again; the stirring and pulping system is used for stirring and pulping materials in the surge bin and then feeding the materials into the pipeline conveying system; the pipeline conveying system is provided with at least two plunger pumps, and the plunger pumps are gathered to the grouting conveying pipeline through the diverter valve and conveyed to a grouting area. The problems of underground filling of the goaf and accumulation of coal-based solid waste are solved through integration of preparation and conveying of coal gangue slurry.

Description

Technical Field

[0001] The invention relates to the technical field of gangue filling and slurry pipeline transportation, and in particular to a system and method for preparing and transporting coal gangue slurry. Background Art

[0002] Coal gangue solid waste is generated during coal mining, which is one of the largest industrial solid wastes in my country. It not only occupies a large amount of farmland and land, but also the gangue leaching water will pollute the surrounding soil and groundwater. The gangue smoke is a harmful gas that will cause serious damage to the surrounding environment. Therefore, the effective treatment of coal gangue is very necessary. At present, the treatment of coal gangue is mainly to crush it to make cement or as an additive to other building materials, but the amount of coal gangue is limited, and there are still limitations in alleviating the pressure of coal gangue solid waste accumulation. In addition, the materials are still transported by traditional means of transportation, and dust will inevitably be generated during transportation, polluting the environment.

[0003] Slurry pipeline transportation technology is a solid material transportation technology that uses water as a medium to prepare solid-liquid mixed slurry with a certain concentration and rheological properties by mixing solid materials and water according to the required particle size, pressurizing it through a pump, and transporting it to the end user through a pipeline. Slurry pipeline transportation technology is green, environmentally friendly, economical and efficient. It has been widely used in many fields such as ore transportation, deep-sea mining, tailings filling and river and lake dredging. Summary of the invention

[0004] The present invention aims to apply slurry pipeline transportation technology to the field of coal gangue solid waste treatment. Through a coal gangue slurry preparation and transportation system, the slurry preparation and transportation of coal gangue are integrated, and the coal gangue is used for underground filling in goaf areas. This is of great significance for solving the common coal-based solid waste accumulation problem in the coal industry and developing new sustainable coal mining projects.

[0005] In view of the above defects or improvement needs of the prior art, according to the first aspect of the present invention, a coal gangue slurry preparation and transportation system for filling goaf is provided, comprising: a material crushing system, a stirring slurry system and a pipeline transportation system;

[0006] The material crushing system includes a storage bin, a vibrating feeder, a multi-stage crushing system, a vibrating screen and a buffer bin; a storage bin is arranged in front of the vibrating feeder, and a multi-stage crushing system is arranged in the rear; the multi-stage crushing system includes multiple sets of crushing device systems, a first set of crushing device systems and a second set of crushing device systems, each crushing device system includes at least two multi-stage crushing devices, one of which is used as a main task device and the other is used as a backup device. After the material is processed by the first set of crushing device systems, it enters the vibrating screen for screening. The qualified coal gangue powder enters the buffer bin, and the unqualified material enters the second set of crushing device systems;

[0007] The stirring and slurrying system is used to stir and slurry the materials in the buffer bin and then send them into the pipeline transportation system;

[0008] The pipeline transportation system is equipped with at least two plunger pumps, one as a running pump and the other as a standby pump. The plunger pump is arranged below the outlet of the distribution hopper. The coal gangue slurry enters the plunger pump inlet by gravity. A safety valve and a cleaning valve are arranged at the outlet of the plunger pump. The slurry delivery pipes behind the pumps are provided with discharge branches, and an electric valve is arranged on the discharge branch. A pressure gauge is arranged on the slurry delivery pipe after the cleaning valve. The slurry delivery pipes behind each plunger pump are aggregated to the grouting delivery pipeline through a diverter valve.

[0009] Furthermore, the crushing device is provided with a plurality of particle size grade devices according to the required particle size of the finished coal gangue powder; the top of the buffer bin may also be provided with a reciprocating belt feeder, and the bottom of the bin is provided with a collecting hopper.

[0010] Furthermore, the mixing and slurrying system includes a gangue metering scale, a belt conveyor, a mixer, a distribution hopper and a water injection system; the gangue metering scale is arranged at the bottom of the buffer bin, and the material falls from the buffer bin onto the gangue metering scale for weighing and proportioning, and then enters the mixer through the belt conveyor; after the material is slurried in the mixer, it enters the pipeline conveying system through the distribution hopper.

[0011] Furthermore, the water injection system includes a mine water treatment station, a water pump, and a water metering scale; the clean water used for pulping is extracted from the mine water treatment station by the water pump, transported to the water metering scale through a water pipeline to quantitatively weigh the clean water according to the set amount, and then transported to the mixer through a pipeline.

[0012] Furthermore, the cleaning valve is also provided with an inlet for a cleaning ball to enter the pipeline, and a recovery port is provided at the outlet of the grouting delivery pipeline; the cleaning ball enters the pipeline through the cleaning valve and is recovered from the recovery port reserved downstream.

[0013] Furthermore, the safety valve and the electric valve are both connected to a pipeline branch that discharges to the ditch; and the electric valve is a double valve group, when one of the electric valves fails or is under maintenance, the other electric valve can continue to operate.

[0014] Furthermore, a concentration meter and a flow meter are arranged on the delivery pipeline at the outlet of the diverter valve; the pipeline after the flow meter is laid according to a set slope, buried below the frozen soil layer, and finally reaches the grouting area.

[0015] According to a second aspect of the present invention, there is also provided a method for preparing and conveying coal gangue slurry for filling a goaf, comprising the following steps:

[0016] a Storage: Store the gangue raw materials in the storage bin;

[0017] b Feeding: The gangue raw materials in the storage bin are evenly transported to the multi-stage crushing system through the vibrating feeder;

[0018] c. Primary crushing: The gangue raw materials are primary crushed in the first set of crushing equipment;

[0019] d. Screening: The gangue after primary crushing is screened through a vibrating screen, and qualified gangue powder enters the buffer bin, and unqualified materials are returned to the second set of crushing devices for secondary crushing; the secondary crushing device and the first set of crushing devices in step c are used as backup for each other to ensure the continuous operation of the multi-stage crushing system;

[0020] e Buffer: Store qualified coal gangue powder after screening in the buffer bin;

[0021] f. Measurement: Use the gangue measuring scale to quantitatively weigh the gangue powder in the buffer bin;

[0022] g. Transportation: The weighed gangue powder is transported to the mixer through a belt conveyor;

[0023] h Pulping water treatment: Mine water is treated in the mine water treatment station and transported to the water metering scale through a water pump;

[0024] i. Water metering: Use a water metering scale to quantitatively weigh the mine water;

[0025] j. Mixing and slurrying: Mix the gangue powder and water in a mixer to make a slurry of a predetermined concentration. The rated capacity of the mixer in step j is 4-6m 3 / times, the mass concentration of the prepared slurry is 74%-75%;

[0026] k. Material distribution: distribute the stirred slurry to the plunger pump through the material distribution hopper;

[0027] 1. Transportation: Use a plunger pump to pressurize and transport the slurry along the pipeline to the grouting area;

[0028] m. Safety monitoring: During the transportation process, the transportation of slurry is monitored and adjusted in real time through safety valves, cleaning valves, pressure gauges, diverter valves, electric valves, concentration meters and flow meters;

[0029] n. Pipeline laying: Lay the pipeline behind the flow meter below the frozen soil layer according to the predetermined slope to avoid collision with other buildings or facilities on the ground and reduce the need for insulation.

[0030] Furthermore, the flow rate of the plunger pump in step 1 is 300-340m 3 / h, the pump pressure is between 19-21MPa, and the delivery pipeline is not less than DN200 high-wear-resistant steel pipe; in the step m, the safety valve is arranged at the outlet of the plunger pump to protect the system safety in the event of overpressure.

[0031] Furthermore, in order to reduce the possibility of clogging, the slurry viscosity is first estimated in step j, and the effects of solid volume fraction, particle size distribution and temperature are considered:

[0032]

[0033] in:

[0034] η(T) is the viscosity of the slurry at temperature T, in Pa·S;

[0035] K(T) is a constant related to temperature T, which indicates the effect of temperature on slurry viscosity;

[0036] C s is the solid volume fraction of the slurry, in %;

[0037] C s，max is the maximum solid volume fraction of the slurry, in %;

[0038] D avg It is the average diameter of solid particles in the slurry, in m;

[0039] D ref is a reference diameter in m used to normalize the effect of particle size;

[0040] n and m are experimentally determined indices that represent the effects of solid volume fraction and particle size on viscosity, respectively;

[0041] Volume fraction C S , using the following formula:

[0042]

[0043] Among them, M solid is the mass of coal gangue powder, M total It is the total mass of coal gangue powder and water.

[0044] The particle size distribution function f(d) can be determined by screening tests or laser particle size analysis, and then the average diameter D is calculated. avg :

[0045]

[0046] The effect of temperature on the constant K(T) can be determined from experimental data. For example, the Arrhenius equation or other empirical models can be used to describe the effect of temperature on slurry viscosity:

[0047]

[0048] Among them, K0 is the viscosity constant at the reference temperature, E is the activation energy, R is the gas constant, and T is the absolute temperature.

[0049] In general, the above technical solutions conceived by the present invention can achieve the following beneficial effects compared with the prior art:

[0050] 1. The coal gangue slurry preparation and conveying system for filling goaf of the present invention adopts a multi-stage crushing system in combination with a vibrating screen. The vibrating screen screens the material processed by the multi-stage crushing system, and returns the screened material with unqualified particle size to the multi-stage crushing system for further graded crushing, thereby achieving accurate control of the particle size of the coal gangue material, effectively improving the output rate of qualified coal gangue powder, ensuring that the particle size of the dry material used in the subsequent slurrying link meets the requirements, and thus improving the operating stability of the entire system and the effect of slurry preparation quality.

[0051] 2. The coal gangue slurry preparation and transportation system for filling goaf areas of the present invention closely combines the buffer bin with the metering scale, and utilizes the buffer bin to temporarily store and cache the coal gangue materials, so that it plays the role of material transfer and balanced material supply, thereby avoiding flow fluctuations during material transportation; on this basis, the metering scale accurately weighs the materials output from the buffer bin in real time, thereby achieving accurate control of the amount of coal gangue materials involved in pulping in each batch, and combining with the subsequent water metering scale and pulping process to achieve accurate batching, stably and efficiently prepare coal gangue slurry that meets the preset concentration requirements, effectively ensuring the continuity and accuracy of the entire pulping process.

[0052] 3. The coal gangue slurry preparation and transportation system for filling goaf of the present invention reasonably sets electric valves in the system. On the one hand, considering that the solid particles in the coal gangue slurry will increase the wear rate of valve components, a double valve group is adopted. When the valve close to the main pipe side fails to close tightly due to wear, the other electric valve can ensure the normal closing function, and when one electric valve is undergoing normal maintenance, the other valve can continue to operate, thereby ensuring the normal and continuous operation of the pipeline transportation system; on the other hand, due to the high pressure of the coal gangue slurry, manual shut-off valve operation is risky, and the switching time of the electric valve is controllable, and manual operation will not accelerate valve wear or cause pipeline vibration due to poor control of the opening degree and valve opening and closing time, and the electric valve is connected to the centralized control system, and can be opened in time when the pipeline has an abnormal overpressure condition, avoiding pipeline pressure build-up and burst, thereby improving the safety of the system. BRIEF DESCRIPTION OF THE DRAWINGS

[0053] Figure 1 The process flow chart of the preferred embodiment of the present invention is as follows;

[0054] Figure 2 It is an enlarged view of the plunger pump of a preferred embodiment of the present invention;

[0055] In all the drawings, the same figure numbers represent the same technical features, specifically: 1-storage silo, 2-vibrating feeder, 310-the first crushing device system, 320-the second crushing device system, 311-multi-stage crushing device, 4-vibrating screen, 5-buffer bin, 6-gangue weighing scale, 7-belt conveyor, 8-mine water treatment station, 9-water pump, 10-water metering scale, 11-mixer, 12-dividing hopper, 13-plunger pump, 14-safety valve, 15-cleaning valve, 16-pressure gauge, 17-diverter valve, 18-electric valve, 19-concentration meter, 20-flow meter, 21-slurry pipe, 22-grouting conveying pipeline, 23-discharge branch pipe. DETAILED DESCRIPTION

[0056] In order to make the purpose, technical solutions and advantages of the present invention more clearly understood, the present invention is further described in detail below in conjunction with the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are only used to explain the present invention and are not intended to limit the present invention. In addition, the technical features involved in the various embodiments of the present invention described below can be combined with each other as long as they do not conflict with each other.

[0057] Example 1

[0058] Please refer to Figure 1 as well as Figure 2 In order to achieve the above-mentioned purpose, this embodiment 1 provides a coal gangue slurry preparation and transportation system for filling goaf, comprising:

[0059] 1. Material crushing system

[0060] Storage silo 1: It is made of large steel structure with a funnel-shaped bottom and lined with anti-wear rubber sheets, which not only increases friction to facilitate the smooth sliding of gangue, but also reduces the wear of the silo wall caused by the falling materials. The top is equipped with a dust cover and a spray dust suppression device to effectively suppress the flying of dust during feeding, with significant environmental protection effects; at the same time, a material level sensor is installed to accurately monitor the amount of gangue in the silo in real time, so as to facilitate the timely arrangement of feeding operations.

[0061] Vibrating feeder 2: It adopts the principle of electromagnetic vibration, and both the amplitude and frequency are adjustable. By closely connecting with the discharge port at the bottom of the storage bin 1, it can accurately control the feeding speed of coal gangue, ensure that the material is evenly and stably transported to the subsequent multi-stage crushing system 3, and avoid equipment blockage or idling due to uneven feeding.

[0062] Multi-stage crushing system: It consists of two sets of crushing device systems, each set contains two multi-stage crushing devices 311. The first set of crushing device system 310's multi-stage crushing device 311 first uses a jaw crusher and an impact crusher combination. The jaw crusher is responsible for coarse crushing, and large pieces of coal gangue with a particle size of >30mm are quickly crushed to 3-30mm, and the impact crusher takes over for medium and fine crushing; the second set of crushing device system 320 is equipped with a cone crusher as a backup and fine processing unit. When the particle size of the material is still unqualified >3mm after being processed by the first set, the cone crusher will accurately crush it to the target particle size with a high crushing ratio. Each system has a spare crusher for each crusher. Through the intelligent electronic control system, it can automatically switch at the moment of failure of the main equipment to ensure production continuity, and the equipment is connected by a closed belt conveyor to reduce material scattering and dust escape.

[0063] Vibrating screen 4: A high-frequency vibrating screen with a screen hole of 3mm is used, and the screening efficiency is as high as over 95%. The screen body is supported by high-strength springs and driven by a vibration motor, which can quickly and accurately classify the crushed materials. The qualified coal gangue powder <3mm falls directly into the buffer bin 5 through the chute, and the unqualified materials on the screen are automatically sent back to the second crushing device system 320 for further processing through the return belt.

[0064] Buffer bin 5: A rotatable material scraper is installed on the top of the bin to ensure uniform distribution of gangue powder and prevent accumulation and compaction; the bottom of the bin is funnel-shaped, with an electric material collection door, which is seamlessly connected to the gangue metering scale 6 to accurately control the discharge amount and ensure the subsequent batching process.

[0065] 2. Mixing pulping system

[0066] Gangue weighing scale 6: It adopts high-precision electronic belt scale to dynamically weigh the weight of the gangue powder output from the buffer bin 5 in real time. The weighing data is transmitted to the central control system in real time to accurately control the feeding amount according to the set formula; the surface of the scale body is specially hardened, wear-resistant and corrosion-resistant, extending the service life.

[0067] Belt conveyor 7: It adopts rubber conveyor belt with anti-skid texture on the belt surface. Protective baffles and cleaning devices are set on both sides of the machine body. It can smoothly and efficiently convey the coal gangue powder weighed by the gangue metering scale 6 to the mixer 11 without spilling the materials in the whole process.

[0068] Mixer 11: Use a twin-shaft forced mixer with a rated capacity of 5m 3 / times, making slurry with a mass concentration of 74%-75%, and the slurry stiffness coefficient is 395.55-522.18mPa·S; the stirring blade has a unique spiral design and is made of high chromium alloy, which is wear-resistant and has excellent stirring effect; the casing is lined with polyurethane wear-resistant plate to reduce material impact wear; equipped with a variable frequency speed motor, the stirring speed can be flexibly adjusted according to the material characteristics and concentration requirements, so as to achieve rapid and uniform mixing of coal gangue powder and water.

[0069] The material distribution hopper 12 is a conical hopper made of stainless steel with a smooth inner wall. An electric gate valve and a flow regulating valve are installed at the bottom to accurately control the flow direction and flow of the slurry, ensuring that the slurry enters the plunger pump 13 stably to avoid blockage and overflow. A liquid level sensor is installed on the outside of the hopper to monitor the slurry level in real time and realize automatic control in conjunction with the central control system.

[0070] Water injection system: The mine water treatment station 8 uses multiple purification processes such as sedimentation, filtration, and reverse osmosis to ensure that the water quality is pure and free of impurities, meeting the water standards for pulping; the water delivery pump 9 uses a centrifugal pump to stably transport the purified water to the water metering scale 10; the water metering scale 10 has the same accuracy standard as the gangue metering scale 6, and accurately measures water according to the formula, and accurately injects it into the mixer 11 through pipelines, flow meters and regulating valves.

[0071] 3. Pipeline transportation system

[0072] Plunger pump 13: equipped with at least two high-power plunger pumps (one main and one backup), the main pump flow rate is 320m 3 / h, pump pressure 20MPa, spare pump of the same model, pump body is cast with high-strength alloy, plunger is ceramic-coated plunger, wear-resistant and corrosion-resistant; pump inlet is equipped with filter, filtration accuracy 3mm, to prevent large particles of coal gangue from entering the pump body and damaging parts; pump outlet and slurry delivery pipe are flange-connected, with reliable sealing. A discharge branch pipe is set behind the two plunger pumps 13. When the pump is stopped due to maintenance or accident, water will be injected through the water pipe on the plunger pump 13 to flush the pipeline to prevent residual slurry from clogging the pipeline. The waste slurry after flushing is discharged into the ditch through the discharge branch pipe.

[0073] Safety valve 14: Installed at the outlet of the plunger pump 13, it adopts a spring-type safety valve with rapid response. It opens instantly when overpressure occurs, and the released slurry is safely discharged to the ditch through the pipeline branch line. The valve body is made of stainless steel, which is resistant to high pressure and erosion, and regular calibration ensures reliable performance. The plunger pump 13 has a high output pressure and is suitable for harsh slurry conditions such as short-distance coarse particles, high concentrations, and high viscosities. It can meet the pipeline transportation requirements of coal gangue slurry. The plunger pump 13 is equipped with an overpressure alarm and cut-off device to protect the safety of the pump equipment and the upstream process system, but the safety of the downstream pipeline transportation system is not guaranteed. The pump outlet safety valve 14 is set to cope with this abnormal overpressure condition and ensure the safety of the pipeline transportation system.

[0074] Cleaning valve 15: It is a ball valve structure, which has two functions: cutting off the slurry delivery pipe at the pump outlet and cleaning the pipeline system. It is equipped with a cleaning ball delivery device. The diameter of the cleaning ball is slightly smaller than the inner diameter of the pipeline. It is made of polyurethane, which has good elasticity and wear resistance. A cleaning ball recovery port is set at the pipeline outlet of the grouting area, and a guide device is set on the pipeline to ensure the smooth operation and recovery of the cleaning ball. Regular cleaning is carried out to keep the inner wall of the pipeline clean and reduce the transportation resistance.

[0075] Pressure gauge 16: The dial is clear and the readings are accurate. It monitors the pump outlet and pipeline pressure in real time. The data is transmitted to the central control system, which is convenient for operators to grasp the pressure dynamics in time and adjust the equipment operating parameters. The outer shell of the gauge has a protective cover, which is shock-resistant and pressure-resistant and can adapt to complex working conditions.

[0076] Diverter valve 17: The electric three-way diverter valve can remotely control the diversion ratio of the slurry, with flexible switching and good sealing. It is tightly connected to the slurry delivery pipe after the running pump and the standby pump, and aggregates the slurry to the grouting delivery pipeline to ensure the continuity and stability of delivery. When the plunger pump 13 switches between the running pump and the standby pump, the diverter valve 17 can be used to quickly switch the working flow channel to improve the delivery efficiency. At the same time, it can reduce the number of bends and the length of the pipeline, optimize the pipeline layout, and prevent pipe blockage.

[0077] Electric valve 18: It adopts the form of double valve group, both of which are electric ball valves, the single valve diameter is DN200, and the switching time is less than 5s; the solid particles in the coal gangue slurry will increase the wear rate of the valve parts. By setting the electric valve 18 double valve group on the discharge branch pipe, the valve close to the main pipe will wear faster. When it fails to close tightly due to wear, the other electric valve 18 can ensure the normal closing function. At the same time, when one of the electric valves 18 is under normal maintenance, the other valve can continue to operate to ensure the normal and continuous operation of the pipeline system. Operation; The pressure of coal gangue slurry is high, and the use of manual shut-off valves will have certain operational risks. In addition, if the opening degree and the opening and closing time of the valve are not well controlled during manual operation, the wear of the valve will be accelerated, or pipeline vibration will be caused. The use of electric valves 18 is safer, and the opening and closing time of the valves is controllable, avoiding abnormal conditions caused by opening and closing the valves too quickly or too slowly; the pressure gauge 16 and the electric valve 18 are both connected to the centralized control system. When the pipeline has an abnormal overpressure condition, the electric valve 18 can be opened in time to avoid pressure buildup and bursting of the pipeline, thereby ensuring the safety of the pipeline transportation system.

[0078] Concentration meter 19: Use an online ultrasonic concentration meter to monitor the solid content of the slurry in real time. The data is fed back to the central control system in real time. The proportion of the pulping process is adjusted in time according to the concentration fluctuation to ensure the stability of the slurry quality.

[0079] Flow meter 20: An electromagnetic flow meter is used to accurately measure the slurry flow rate, providing key data for the speed regulation of the plunger pump 13 and the system capacity accounting; the flow meter is installed in the horizontal straight pipe section, and sufficient straight pipe length is reserved before and after to ensure accurate measurement; the data is connected to the central control system to realize visual monitoring and regulation of the flow. The line pipeline after the flow meter 20 slopes underground according to the laying angle determined by the experiment to below the frozen soil layer. The pipeline is buried to avoid collision with other buildings or facilities on the ground. At the same time, the pipeline is below the frozen soil layer and does not need insulation.

[0080] Example 2

[0081] In order to achieve the above-mentioned purpose, this embodiment 2 provides a method for preparing and conveying coal gangue slurry for filling a goaf, comprising:

[0082] Material preparation and crushing process: Gangue raw materials are transported to storage bin 1 by mining area transport vehicles. When unloading, the spray dust suppression device is turned on to suppress dust; feed in time according to the data of the material level sensor. Start the vibrating feeder 2, set the feeding speed according to the production plan, and the gangue falls evenly into the first set of crushing device system 310. In the coarse crushing stage, the jaw crusher quickly crushes the gangue with a particle size of more than 30mm to 3-30mm; in the medium and fine crushing, the impact crusher reduces the material particle size to less than 3mm, and the crushed material is sent to the vibrating screen 4 for screening via a belt conveyor. Qualified gangue powder with a particle size of less than 3mm under the screen enters the buffer bin 5; unqualified materials on the screen are automatically transported to the second set of crushing device system 320 by the return belt, and the cone crusher accurately crushes it again until the particle size meets the standard. During the whole process, all equipment works in coordination according to the instructions of the central control system to ensure efficient and stable crushing process.

[0083] Mixing and slurrying operation steps: the electric material collecting door at the bottom of the buffer bin 5 opens according to the set amount, and the gangue powder falls to the gangue weighing scale 6. After the scale body accurately weighs the gangue powder, it is transported to the mixer 11 through the belt conveyor 7; at the same time, the purified water from the mine water treatment station 8 is extracted through the water pump 9, and the water metering scale 10 takes the weight of water that matches the weight of the gangue powder, and injects it into the mixer 11 through the pipeline and the regulating valve.

[0084] To reduce the possibility of clogging, the viscosity is estimated before slurrying, taking into account the effects of solid volume fraction, particle size distribution and temperature:

[0085]

[0086] in:

[0087] η(T) is the viscosity of the slurry at temperature T, in Pa·S;

[0088] K(T) is a constant related to temperature T, which indicates the effect of temperature on slurry viscosity;

[0089] C S is the solid volume fraction of the slurry, in %;

[0090] C S，max is the maximum solid volume fraction of the slurry, in %;

[0091] D avg It is the average diameter of solid particles in the slurry, in m;

[0092] D ref is a reference diameter in m used to normalize the effect of particle size;

[0093] n and m are experimentally determined indices that represent the effects of solid volume fraction and particle size on viscosity, respectively;

[0094] Volume fraction C S , using the following formula:

[0095]

[0096] Among them, M solid is the mass of coal gangue powder, M total It is the total mass of coal gangue powder and water.

[0097] The particle size distribution function f(d) can be determined by screening tests or laser particle size analysis, and then the average diameter D is calculated. avg :

[0098]

[0099] The effect of temperature on the constant K(T) can be determined from experimental data. For example, the Arrhenius equation or other empirical models can be used to describe the effect of temperature on slurry viscosity:

[0100]

[0101] Among them, K 0 is the viscosity constant at the reference temperature, E is the activation energy, R is the gas constant, and T is the absolute temperature.

[0102] If the estimated viscosity is too high, it may cause blockage easily. You can adjust various parameters of system operation to reduce the viscosity.

[0103] After the gangue powder and the water required for slurrying enter the mixer, start the mixer 11, stir at a low speed for 5 minutes to initially mix the materials, and then adjust to high speed for 15 minutes to make a slurry with a mass concentration of 75%. The slurry is regulated by the electric gate valve and flow regulating valve at the bottom of the hopper 12, and flows smoothly into the plunger pump 13. The batching and stirring parameters of each link in this process are accurately controlled by the central control system according to the preset process to ensure that the slurry quality meets the standards.

[0104] Pipeline transportation operation mode: The main pump of the plunger pump 13 is started, and the slurry moves forward along the pipeline under the action of the pump pressure. The pump outlet pressure is monitored in real time by the pressure gauge 16; the safety valve 14 is in standby state, and it is quickly opened to release when overpressure occurs. During operation, the cleaning valve 15 is opened regularly every month to release the pipe cleaning ball to clean the coal gangue attached to the inner wall of the pipeline, and the pipe cleaning ball is taken out from the downstream recovery port; the electric valve 18 is automatically adjusted according to the system pressure and flow. When one side of the valve fails, the other valve is seamlessly switched to ensure the smooth flow of the pipeline. The diverter valve 17 flexibly adjusts the slurry diversion ratio according to the working conditions, and stably aggregates the slurry after the operating pump and the standby pump to the grouting delivery pipeline; the concentration meter 19 and the flow meter 20 monitor the slurry concentration and flow in real time, and the data is fed back to the central control system. The operator fine-tunes the parameters such as the speed of the plunger pump 13 and the opening of each valve to ensure that the slurry is stably and accurately delivered to the grouting area of ​​the goaf along the delivery pipeline laid below the frozen soil layer, and the whole process is intelligently and finely controlled to achieve efficient and safe transportation.

[0105] It will be easily understood by those skilled in the art that the above description is only a preferred embodiment of the present invention and is not intended to limit the present invention. Any modifications, equivalent substitutions and improvements made within the spirit and principles of the present invention should be included in the protection scope of the present invention.

Claims

1. A coal gangue slurry preparation and delivery system for filling goaf, characterized in that: include: Material crushing system, mixing and slurrying system and pipeline transportation system; The material crushing system comprises a storage bin (1), a vibrating feeder (2), a multi-stage crushing system, a vibrating screen (4) and a buffer bin (5); the storage bin (1) is arranged in front of the vibrating feeder (2), and the multi-stage crushing system is arranged in the rear; the multi-stage crushing system comprises a plurality of crushing device systems, a first crushing device system (310) and a second crushing device system (320), each crushing device system comprises at least two multi-stage crushing devices (311); the material is processed by the first crushing device system (310) and then enters the vibrating screen (4); after screening, the qualified coal gangue powder enters the buffer bin (5), and the unqualified material enters the second crushing device system (320); The stirring and slurrying system is used to stir and slurry the materials in the buffer bin (5) and then send them into the pipeline transportation system; The pipeline transportation system is equipped with at least two plunger pumps (13). The plunger pump (13) is arranged below the outlet of the distribution hopper (12). The coal gangue slurry enters the inlet of the plunger pump (13) by gravity. A safety valve (14) and a cleaning valve (15) are arranged at the pump outlet. The slurry delivery pipes behind the plunger pump (13) are all provided with discharge branches, and an electric valve (18) is arranged on the discharge branch pipe; a pressure gauge (16) is arranged on the slurry delivery pipe after the cleaning valve (15); and the slurry delivery pipe (21) behind each plunger pump is converged to the grouting delivery pipe (22) through a diverter valve (17).

2. The system for preparing and conveying coal gangue slurry for filling goaf according to claim 1, characterized in that: The crushing device (311) is provided with a plurality of particle size grade devices according to the required particle size of the finished coal gangue powder; the top of the buffer bin (5) may also be provided with a reciprocating belt feeder, and the bottom of the bin is provided with a collecting hopper.

3. The system for preparing and conveying coal gangue slurry for filling goaf according to claim 1, characterized in that: The mixing and slurrying system comprises a gangue weighing scale (6), a belt conveyor (7), a mixer (11), a material distribution hopper (12) and a water injection system; the gangue weighing scale (6) is arranged at the bottom of a buffer bin (5); materials fall from the buffer bin (5) onto the gangue weighing scale (6) and are weighed and proportioned before entering the mixer (11) through the belt conveyor (7); after the materials are slurried in the mixer (11), they enter the pipeline conveying system through the material distribution hopper (12).

4. The system for preparing and conveying coal gangue slurry for filling goaf according to claim 1, characterized in that: The water injection system comprises a mine water treatment station (8), a water delivery pump (9), and a water metering scale (10); clean water used for pulping is extracted from the mine water treatment station (8) by the water delivery pump (9), transported to the water metering scale (10) through a water delivery pipeline, and the clean water is quantitatively weighed according to a set amount, and then transported to the mixer (11) through a pipeline.

5. The system for preparing and conveying coal gangue slurry for filling goaf according to claim 1, characterized in that: The cleaning valve (15) is also provided with an inlet for a cleaning ball to enter the pipeline, and a recovery port is provided at the outlet of the grouting delivery pipeline (22); the cleaning ball enters the pipeline through the cleaning valve (15) and is recovered from the recovery port reserved downstream.

6. The system for preparing and conveying coal gangue slurry for filling goaf according to claim 1, characterized in that: The safety valve (14) and the electric valve (18) are both connected to a pipeline branch line that discharges to a trench; and the electric valve (18) is a double valve group, so that when one of the electric valves (18) fails or is under maintenance, the other electric valve (18) can continue to operate.

7. A system for preparing and conveying coal gangue slurry for filling goaf according to any one of claims 1 to 6, characterized in that: A concentration meter (19) and a flow meter (20) are arranged on the grouting delivery pipeline (22) at the outlet of the diverter valve (17); the pipeline after the flow meter (20) is laid according to a set slope, buried below the frozen soil layer, and finally reaches the grouting area.

8. A method for preparing and conveying coal gangue slurry for filling goaf, characterized in that: The following steps are involved: a. Storage: storing the gangue raw materials in a storage bin (1); b. Feeding: The gangue raw materials in the storage bin (1) are evenly transported to the multi-stage crushing system (3) through a vibrating feeder (2); c. Primary crushing: The gangue raw materials are primary crushed in the first set of crushing equipment; d. Screening: The gangue after primary crushing is screened by a vibrating screen (4), and qualified gangue powder enters a buffer bin (5), and unqualified materials are returned to the second set of crushing devices for secondary crushing; the secondary crushing device and the first set of crushing devices in step c are used as backup to ensure the continuous operation of the multi-stage crushing system; e. Buffer: storing the screened qualified gangue powder in the buffer bin (5); f Measurement: Use the gangue metering scale (6) to quantitatively weigh the gangue powder in the buffer bin (5); g. Transport: The weighed gangue powder is transported to the mixer (11) via a belt conveyor (7); h. Pulping water treatment: treating the mine water in the mine water treatment station (8) and delivering it to the water metering scale (10) through the water delivery pump (9); i. Water metering: using a water metering scale (10) to quantitatively weigh the mine water; j. Mixing and slurrying: In a mixer (11), the gangue powder and water are mixed to form a slurry of a predetermined concentration; the rated capacity of the mixer (11) is 4-6m 3 / times, the mass concentration of the prepared slurry is 74%-75%; k. Material distribution: The stirred slurry is distributed to the plunger pump (13) through the material distribution hopper (12); l. Transport: The slurry is transported along the pipeline to the grouting area by pressurizing the plunger pump (13); m. Safety monitoring: During the transportation process, the transportation of the slurry is monitored and adjusted in real time through the safety valve (14), the cleaning valve (15), the pressure gauge (16), the diverter valve (17), the electric valve (18), the concentration meter (19) and the flow meter (20); n. Pipeline laying: Lay the pipeline after the flow meter (20) below the frozen soil layer at a predetermined slope to avoid collision with other buildings or facilities on the ground and reduce insulation requirements.

9. The method for preparing and conveying coal gangue slurry for filling goaf according to claim 8, characterized in that: The flow rate of the plunger pump (13) in step 1 is 300-340m 3 / h, the pump pressure is between 19-21MPa, and the delivery pipeline is not less than a high-wear-resistant steel pipe of DN200 specification; the safety valve (14) in step m is arranged at the outlet of the plunger pump (13) to protect the system safety in the event of overpressure.

10. The method for preparing and conveying coal gangue slurry for filling goaf according to claim 8, characterized in that: In step j, the slurry viscosity is first estimated, taking into account the effects of solid volume fraction, particle size distribution and temperature: in: η(T) is the viscosity of the slurry at temperature T, in Pa·S; K(T) is a constant related to temperature T, which indicates the effect of temperature on slurry viscosity; C S is the solid volume fraction of the slurry, in %; C S，max is the maximum solid volume fraction of the slurry, in %; D avg It is the average diameter of solid particles in the slurry, in m; D ref is a reference diameter in m used to normalize the effect of particle size; n and m are experimentally determined indices that represent the effects of solid volume fraction and particle size on viscosity, respectively; Volume fraction C S , using the following formula: Among them, M solid is the mass of coal gangue powder, M total is the total mass of coal gangue powder and water; Calculate the average diameter D avg : The particle size distribution function f(d) is determined by screening tests or laser particle size analysis, and then the effect of temperature on the constant K(T) is determined by experimental data, using the Arrhenius equation or other empirical models to describe the effect of temperature on slurry viscosity: Where K0 is the viscosity constant at the reference temperature, E is the activation energy, R is the gas constant, and T is the absolute temperature.

Images