Return air waste heat circulation consolidation system for coal slime-based filling material

Abstract

The utility model belongs to the field of coal mine cemented filling mining, and particularly discloses a return air waste heat circulating consolidation system for a coal slime-based filling material, which is characterized in that a heat exchange pipeline is pre-buried in a filling body between coal pillars, mine return air waste heat is utilized to accelerate dehydration consolidation of the coal slime-based filling material, and seepage water is recovered to realize secondary utilization. The system comprises an air inducing device, a heat preservation pipeline, a gas flow dividing device, a heat exchange pipeline and a water storage device. The air inducing device is arranged at the air return well bottom; the upper part of the heat exchange pipeline is arranged in the water permeable tank and is used for accelerating dehydration and solidification of the coal slime-based filling material and collecting exuded water; the heat exchange pipelines are all connected to the same gas distribution device which is connected with an air inducing device through a heat preservation pipeline. The tail end of the heat exchange pipeline is connected with a water storage device. The device has the characteristics of economy, energy conservation, environmental protection and high dehydration efficiency, the compactness and the early strength of a filling body are remarkably improved, and the energy consumption and the environmental influence of filling mining are reduced.

Description

TECHNICAL FIELD

[0001] The utility model relates to the field of coal mine cemented filling mining, especially relates to a back air waste heat circulation consolidation system for slime base filling material. BACKGROUND

[0002] In the process of coal mining, the heat of the working face mainly comes from the heat dissipation of the coal wall, human body and mechanical equipment, and the heat brought out by the gas gushing in the coal body. These heat exchanges with the air at the bottom of the well, causing the temperature of the back air flow to rise, thereby taking away most of the heat of the working face. After leaving the working face, affected by the ground temperature of the coal mine, the heat loss of the back air flow is less, and the temperature is basically constant. According to statistics, most of the back air flow temperature in winter remains above 15 DEG C, with stable and high-quality characteristics, and has high utilization value.

[0003] Room and pillar mining method is a commonly used method in coal mining in China, but if the coal pillar is not recovered, it will lead to waste of a large amount of high-quality coal resources and spontaneous combustion of residual coal; if the coal pillar is directly mined, the stable structure between the coal pillar and the roof and floor may be damaged. Therefore, how to safely and efficiently recover the coal pillar has become a key problem restricting the development of coal mines.

[0004] Due to the limitation of the size of the coal pillar and the stress of the surrounding rock, the traditional coal pillar recovery methods mainly include bag wing type, external type and split column type, but these methods have the disadvantages of low recovery rate and high safety risk. In order to solve this problem, the coal slime base filling material is used to fill the coal room goaf, and then the whole is recovered after solidification. This method can realize the recovery of all coal pillars and reduce the possibility of mine pressure and spontaneous combustion. However, the coal slime base filling material has the disadvantages of low dehydration efficiency and long period, and incomplete dehydration of the filling body will cause structural defects. Therefore, accelerating the dehydration and consolidation of the coal slime base filling material is the focus of the current research.

[0005] The traditional dehydration and consolidation method of coal slime base filling material mainly relies on natural drying or external heating, but these methods have the problems of low efficiency and high energy consumption. UTILITY MODEL CONTENT

[0006] The utility model aims at providing a back air waste heat circulation consolidation system for coal slime base filling material, which solves the above technical problems existing in the prior art.

[0007] To achieve the above object, the utility model provides the following scheme: a kind of back air waste heat circulation consolidation system for coal slime base filling material, including several heat exchange pipes embedded in filling body between coal pillar, the upper portion of heat exchange pipe is located in water permeable tank, for accelerating the dehydration consolidation of coal slime base filling material and collecting exuded moisture;The heat exchange pipes are all connected to the same gas shunting device, the gas shunting device is connected to air induction device by heat preservation pipeline, and the air induction device is arranged at the bottom of back air shaft, for introducing mine back air containing waste heat;The end of heat exchange pipe is connected with water storage device, for storing recycled moisture and realizing secondary use.

[0008] The above structure aims at providing a back air waste heat circulation consolidation system with economic energy saving, green environmental protection and high dehydration efficiency, which recycles and utilizes mine back air waste heat by arranging air induction device at the bottom of back air shaft, so that the heat source is stable, and resource waste caused by directly discharging back air into atmosphere is avoided, heat exchange pipes made of heat-conducting material are arranged in filling body, the heat exchange contact area is increased, the dehydration consolidation speed of coal slime base filling material can be effectively accelerated by the heat, and the production efficiency of filling mining operation is improved.

[0009] In some optional schemes of the utility model, at least one booster fan is arranged at a preset distance position along the length direction of the heat preservation pipeline.

[0010] In some optional schemes of the utility model, the air induction device comprises:

[0011] The filter screen is detachably installed at the air inlet of the air induction device, and is used for intercepting solid particles in air flow.

[0012] The high-pressure spray gun is detachably connected to the inner side of the air inlet of the air induction device, and is used for cleaning the filter screen.

[0013] The air induction device in the utility model can filter coal dust, rock dust and other impurities in air flow through the filter screen, and is provided with a high-pressure spray gun, so that when the amount of impurities is too large, the blocked filter screen can be cleaned regularly by spraying gas or liquid during non-working time, and the filter screen can be replaced when the service life is reached.

[0014] In some optional schemes of the utility model, the gas shunting device has an annular pressure balance cavity, and one end of each heat exchange pipe is communicated with the annular pressure balance cavity.

[0015] In some optional schemes of the utility model, the connection position of the annular pressure balance cavity and the heat exchange pipe is provided with a porous plate, and a plurality of through holes are arranged on the porous plate, for regulating the flow and distribution of air flow.

[0016] In some optional schemes of the utility model, one side of each of the plurality of porous plates is connected with an adjusting valve, the adjusting valve is used for controlling the number of passages in the porous plate, and the air flow distribution of different heat exchange pipes is realized.

[0017] The gas distribution device is designed as an annular pressure balance cavity, can reduce the wind speed by expanding the flow area, and installs a porous plate in front of the distribution pipeline to reduce the air pressure and flow rate in the heat exchange pipeline, avoids the reduction of the heat exchange efficiency and water seepage effect of hot air flow and the filling body caused by excessive air pressure and flow rate, simultaneously realizes the quantitative regulation and control of the air flow, and improves the applicability and flexibility of the system.

[0018] In some optional schemes of the utility model, the heat exchange pipeline is arranged in the middle and lower part of the filling body in the goaf in an inclined manner, and the inclination angle is 2-5°.

[0019] In some optional schemes of the utility model, the outer diameter of the heat exchange pipeline is 1 / 8-1 / 10 of the height of the goaf.

[0020] In some optional schemes of the utility model, a water permeable groove is formed in the upper part of the heat exchange pipeline, the water permeable groove extends along the length direction of the heat exchange pipeline, a layer of geotextile is installed in the middle of the water permeable groove, and one layer of iron wire mesh is installed above and below the geotextile.

[0021] The water permeable groove is formed in the upper part of the heat exchange pipeline, can make the excess water in the filling material enter the pipeline and be discharged into the water storage device, realizes the secondary utilization of the mine water, and the water permeable groove is alternately arranged with the water permeable slurry separation material geotextile and the iron wire mesh, effectively prevents the large particles from entering the heat exchange pipeline and causing the pipe blockage problem while ensuring that the pipeline is not damaged.

[0022] In some optional schemes of the utility model, the mesh size of the iron wire mesh satisfies the formula:

[0023] d net ≤k×d interception ;

[0024] Wherein, d net is the mesh size of the iron wire mesh, k is a safety margin coefficient, the value is 0.7-0.9, and d interception is the equivalent particle diameter of D30 particles in the coal slime based filling material.

[0025] In some optional schemes of the utility model, a water storage device is connected to the end of the heat exchange pipeline, the water storage device is used for storing the water seeped from the filling body, a liquid level sensor and a drain valve are installed in the water storage device, and an exhaust port capable of filtering air flow is arranged above the liquid level sensor.

[0026] Further, the drainage port is arranged at the bottom of the water storage device upward 1 / 4 height, which can reduce the discharge of water bottom sediments, and the bottom plate of the water storage device is detachable, so that the sediments can be cleaned separately during non-working time.

[0027] The utility model discloses further arrange water storage device in heat exchange pipeline end, can be used to store the water that fills the body and filters the air current, when liquid storage is too much or after standing and depositing, can open the drain valve and discharge water through the drainage port, and after further water purification treatment, can be used as filling material water, mining equipment cooling and spray dust removal secondary utilization.

[0028] Compared with the prior art, the utility model discloses at least the following beneficial effects:

[0029] The utility model discloses a kind of back air waste heat circulation consolidation systems for coal slime-based filling material, with remarkable economic, environmental protection and efficiency promotion effect. By recycling mine back air waste heat, avoid energy waste, reduce the external heating energy consumption needed by traditional dehydration consolidation method, significantly reduce the operating cost of filling mining. At the same time, system utilizes mine back air waste heat to accelerate the dehydration consolidation speed of coal slime-based filling material, shortens the consolidation period, improves the production efficiency of filling mining operation. In addition, system recovers the water that fills the body and realizes secondary utilization, reduces the waste of mine water, and is friendly to environment. BRIEF DESCRIPTION OF DRAWINGS

[0030] In order to more clearly illustrate the technical scheme in the embodiments of the utility model or prior art, the drawings needed to be used in the embodiments will be simply introduced below, and obviously, the drawings in the following description are only some embodiments of the utility model, and other drawings can be obtained according to these drawings without creative labor for those skilled in the art.

[0031] Figure 1 It is the whole structure schematic diagram of the back air waste heat circulation consolidation system for coal slime-based filling material proposed by the utility model;

[0032] Figure 2 It is the front face outer shape structure diagram of the air induction device in the system of the utility model;

[0033] Figure 3 It is the side face internal structure diagram of the air induction device in the system of the utility model;

[0034] Figure 4 It is the structure diagram of the air induction device air inlet in the system of the utility model;

[0035] Figure 5 It is the structure diagram of the air induction device outlet in the system of the utility model;

[0036] Figure 6It is a structure schematic view of the gas shunting device in the system of the utility model;

[0037] Figure 7 It is a structure schematic view of the gas shunting device in the system of the utility model; Figure 6 It is a sectional view at A-A in the system of the utility model;

[0038] Figure 8 It is a structure schematic view of the heat exchange pipeline unit in the system of the utility model;

[0039] Figure 9 It is a structure schematic view of the heat exchange pipeline unit in the system of the utility model; Figure 8 It is a sectional view at B-B in the system of the utility model;

[0040] Figure 10 It is a structure schematic view of the heat exchange pipeline unit in the system of the utility model; Figure 9 It is a sectional view at C in the system of the utility model;

[0041] Figure 11 It is a structure schematic view of the water storage device in the system of the utility model;

[0042] Figure 12 It is a position schematic view of the heat exchange pipeline in the system of the utility model.

[0043] In the drawing: 1, air induction device; 11, filter screen; 12, high-pressure spray gun; 2, heat preservation pipeline; 3, gas shunting device; 31, annular pressure balance cavity; 32, multi-hole plate; 33, regulating valve; 4, booster fan; 5, heat exchange pipeline; 51, water permeable groove; 52, water permeable hole; 53, geotextile; 54, wire mesh; 6, water storage device; 61, liquid level sensor; 62, drain valve; 63, exhaust port; 7, air return well. DETAILED DESCRIPTION

[0044] The technical solutions in the embodiments of the utility model will be clearly and completely described below with reference to the drawings in the embodiments of the utility model. Obviously, the described embodiments are only part of the embodiments of the utility model, rather than all the embodiments. Based on the embodiments in the utility model, all other embodiments obtained by those skilled in the art without creative labor fall within the protection scope of the utility model.

[0045] The utility model discloses based on the limitation of existing mine air return waste heat utilization technology and the problem existing in the application of coal slime based filling material, and proposes a kind of air return waste heat circulation consolidation system for coal slime based filling material, mainly used for the consolidation of coal slime based filling material in room and pillar mining. By pre-arranging pipeline in filling body, mine air return dust removal after being introduced into pipeline with waste heat, the dehydration consolidation of filling body is accelerated using its heat, while the water migration path is regulated, the water exuded in filling body is output and recycled through pipeline, realizes the secondary use of mine water, improves the compactness and early strength of filling body, with the characteristics of economic energy saving, green environmental protection, high dehydration efficiency.

[0046] In order to make the above-mentioned purposes, features and advantages of the present application more apparent and understandable, the present application will be further described in detail below with reference to the drawings and specific embodiments.

[0047] Referring to Figures 1 to 12 The utility model embodiment provides a kind of back air waste heat circulation consolidation system for slime-based filling material, including air induction device 1, heat preservation pipeline 2, gas shunt device 3, relay fan 4, heat exchange pipeline 5, water storage device 6;The air induction device 1 is arranged in the well bottom of back air shaft 7, is connected to gas shunt device 3 by heat preservation pipeline 2, and the gas shunt device 3 is used to shunt hot air into different positions heat exchange pipeline 5;The heat exchange pipeline 5 is prearranged in coal pillar before filling, and water-permeable groove 51 is opened in its upper portion;The water storage device 6 is arranged at the end of heat exchange pipeline 5;When the transport distance is longer, one or more relay fans 4 are provided on the heat preservation pipeline 2, and the relay fan 4 supplies power to air flow in the middle of pipeline.

[0048] In one specific embodiment, as Figures 2 to 5 The air induction device 1 includes device body, fan rotating in device body, and fan transmission connection, the device body has circular air inlet and square air outlet, and filter screen 11 is installed at air inlet, for intercepting coal dust, rock dust and other impurities in air flow. Further, high-pressure spray gun 12 is installed inside the air inlet of the device body, and the high-pressure spray gun 12 is used to spray high-pressure gas or liquid at non-working time, to clean the impurities accumulated on the filter screen 11.

[0049] The air induction device 1 is used to introduce air flow into heat preservation pipeline 2, and heat preservation pipeline 2 is connected between air induction device 1 and relay fan 4 / gas shunt device 3, to reduce heat loss of hot air flow. Since there are coal dust, rock dust and other impurities in the air flow, filter screen 11 is installed at the air inlet of air induction device 1 to intercept impurities. However, long-term work can cause dust accumulation to block filter screen 11, resulting in reduced air induction efficiency. Therefore, high-pressure spray gun 12 is arranged inside the air inlet, which can spray high-pressure gas or liquid to periodically clean the blocked filter screen 11 at non-working time, and the filter screen 11 can be removed and replaced.

[0050] In one specific embodiment, as Figure 6 And Figure 7As shown, the gas shunting device 3 has a ring-shaped pressure balance cavity 31 inside the gas shunting device 3 for expanding the flow area of the air flow; by expanding the flow area, the dynamic pressure of the air flow is converted into static pressure, thereby reducing the wind speed and wind pressure of the air flow; this design can effectively avoid the problem of excessive wind speed caused by excessive wind pressure in the heat exchange pipe 5, thereby reducing the heat exchange efficiency and water infiltration effect of the hot air flow and the filling material. The ring-shaped pressure balance cavity 31 is connected to a plurality of heat exchange pipes 5, and a plurality of perforated plates 32 are installed between the ring-shaped pressure balance cavity 31 and the heat exchange pipes 5, and a plurality of through holes are provided on the perforated plates 32 for further regulating the flow and distribution of the air flow. At the same time, an adjusting valve 33 is connected to each perforated plate 32, and the adjusting valve 33 is used to control the number of passages in the perforated plate 32, and by adjusting the opening degree of the adjusting valve 33, the flow of the air flow can be quantitatively regulated, thereby realizing the distribution of the air flow to different heat exchange pipes 5.

[0051] As can be seen from the above structure, the gas shunting device 3 is connected between the heat preservation pipe 2 and the heat exchange pipe 5 for shunting the air flow; excessive wind pressure in the heat exchange pipe 5 can cause excessive wind speed, thereby reducing the drying and water infiltration effect; therefore, a ring-shaped pressure balance cavity 31 is provided inside the shunting device to reduce the wind speed by expanding the flow area, reduce the wind pressure in the heat exchange pipe 5, and a plurality of perforated plates 32 are provided between the balance cavity and the heat exchange pipe 5 to realize quantitative regulation of the air flow by adjusting the number of passages in the perforated plate 32 through the adjusting valve 33. The combination of the ring-shaped pressure balance cavity 31, the perforated plate 32 and the adjusting valve 33 of the gas shunting device 3 realizes accurate regulation of the flow and wind pressure of the hot air flow. It can effectively avoid the problem of excessive wind speed caused by excessive wind pressure in the heat exchange pipe 5, and at the same time, the quantitative distribution of the air flow is realized through the adjusting valve 33, thereby improving the flexibility and applicability of the system.

[0052] In one specific embodiment, as shown in Figure 8 and Figure 9 As shown, the heat exchange pipe 5 includes a pipe body made of aluminum alloy, which has high strength and good thermal conductivity. A water permeable groove 51 is formed in the upper part of the pipe body, which extends along the axial direction of the pipe body. A layer of water-permeable and slurry-impermeable material is installed in the middle of the water permeable groove 51 to prevent solid particles from entering the pipe. The entire water permeable groove 51 is used to collect excess water seepage from the coal slime-based filling material. Specifically, the water-permeable and slurry-impermeable material is a geotextile 53, and a layer of iron mesh 54 is installed on the upper and lower parts of the geotextile 53. The surface of the iron mesh 54 is coated with a coating to improve its wettability and promote drainage. The iron mesh 54 is installed on the upper and lower sides of the water permeable groove 51 to support the geotextile 53 and prevent it from being crushed. The mesh size of the iron mesh 54 is designed to allow water to pass through while preventing most solid particles from entering the pipe.

[0053] Further optimization scheme, mesh size design formula as follows:

[0054] d net ≤k×d interception

[0055] In the formula, d net Mesh size, mm; k is the safety margin coefficient, take 0.7~0.9; d interception Key intercept size, take D30 (cumulative particle size distribution of solid particles reaches 30% when corresponding to the equivalent particle size). Particle size less than D30 slurry particles can form filter cake layer on the mesh, further block the entry of solid particles, avoid the generation of pipe blockage problem, prevent the filter cake from constantly thickening under the action of gas pressure to affect the water permeability.

[0056] Further optimization scheme, the water permeable tank 51 is provided with two rows of water permeable holes 52 on both sides, each row includes a plurality of water permeable holes 52 arranged equidistantly along the length direction of the heat exchange pipeline 5. In the embodiment, the number of the two rows of water permeable holes 52 is same, the positions are one-to-one corresponding, and the structure of the single water permeable hole 52 is similar to that of the water permeable tank 51, and each includes a layer of geotextile 53 and two layers of iron wire mesh 54 distributed above and below the geotextile 53, and the mesh design of the iron wire mesh 54 is consistent with that of the water permeable tank 51.

[0057] Further optimization scheme, the heat exchange pipeline 5 is arranged in the lower part of the filling body in the goaf, and an inclination angle of 2-5° is arranged, which is used for heating and drying the filling body and providing the condition for the water in the pipeline to flow into the water storage device 6 by itself, and the outer diameter of the heat exchange pipeline 55 is 1 / 8-1 / 10 of the height of the goaf, so as to reduce the influence on the strength of the filling body.

[0058] In one specific embodiment, as shown in Figure 1 And Figure 11 The water storage device 6 is connected at the end of the heat exchange pipeline 5, is used for storing the water seeped from the filling body, and is internally provided with a liquid level sensor 61 and a drain valve 62, the exhaust port 63 for filtering air flow is arranged above the liquid level sensor 61, and the exhaust port 63 cooperates with the water below to reduce the content of harmful gas or dust in the air flow, the drain valve 62 is automatically opened to discharge the water through the drain port when the liquid storage is too much, the drain port is arranged at the bottom of the water storage device 6 and upwardly by 1 / 4 height, which can reduce the discharge of the sediment at the bottom of the water, the bottom plate of the water storage device 6 is detachable, and the sediment is cleaned separately during non-working time.

[0059] The working principle of the embodiment of the utility model is as follows:

[0060] The hot air at the bottom of the air return shaft 7 is introduced into the heat preservation pipeline 2 after being filtered by the air guide device 1. When the coal dust and rock dust in the air guide device 1 are accumulated too much, the high-pressure spray gun 12 can be used for cleaning. The hot air flow is transported to the filling working face in the heat preservation pipeline 2, and the heat preservation pipeline 2 can effectively reduce the heat loss of the air flow in the pipeline during the flow process. After the hot air flow reaches the working face, the flow and air pressure are regulated by the gas flow dividing device 3, and are divided into different heat exchange pipelines 5. The hot air flow entering the heat exchange pipeline 5 exchanges heat with the coal slime-based filling material by using the temperature of the hot air flow, so that the drying and solidification speed of the filling material is accelerated. The filtered air flow is discharged, and the water seeping from the filling material can enter the pipeline through the water permeable groove 51 on the upper portion of the heat exchange pipeline 5 and be transported to the water storage device 6 at the end of the heat exchange pipeline 5, so that the water is reused.

[0061] Compared with the prior art, the back air waste heat recycling and solidification system for the coal slime-based filling material provided by the embodiment of the utility model realizes the filtration of impurities in the air flow and avoids the accumulation of impurities to affect the efficiency. The system transports the mine back air with a higher temperature to the working face, and regulates the flow and air pressure through the annular flow dividing device, so that the heat exchange with the coal slime-based filling material is directly performed, thereby accelerating the drying and solidification speed of the filling material and indirectly improving the recovery efficiency. Meanwhile, the water seeping from the filling material is transported to the water storage device 6 through the heat exchange pipeline 5, so that the mine water resource is reused, and the influence on the environment in the mining process is reduced. The system has the characteristics of economic energy saving, green environmental protection, high back air waste heat utilization rate, good solidification effect of the coal slime-based filling material, low construction difficulty and no pollution, and meets the demand of sustainable development.

[0062] In the description of the utility model, it is understood that the orientation or position relationship indicated by the terms "longitudinal", "transverse", "upper", "lower", "front", "rear", "left", "right", "vertical", "horizontal", "top", "bottom", "inner", "outer" and the like is the orientation or position relationship shown in the drawings, and is only for the convenience of describing the utility model, and does not indicate or imply that the indicated device or element must have a particular orientation, be constructed and operated in a particular orientation, and therefore cannot be understood as a limitation on the utility model.

[0063] The above-described embodiments are only used to describe the preferred modes of the utility model, and do not limit the scope of the utility model, and various modifications and improvements to the technical scheme of the utility model made by those skilled in the art without departing from the design spirit of the utility model should fall within the protection scope of the utility model claim.

Claims

1. A return air waste heat circulation consolidation system for coal slime-based backfill materials, characterized in that, The system includes several heat exchange pipes (5) embedded in the filling body between coal pillars. The upper part of the heat exchange pipes (5) is located in a permeable trough (51) to accelerate the dehydration and consolidation of the coal slime-based filling material and collect the seepage water. All heat exchange pipes (5) are connected to the same gas diversion device (3). The gas diversion device (3) is connected to an exhaust fan (1) through an insulated pipe (2). The exhaust fan (1) is located at the bottom of the return air shaft (7) to introduce mine return air containing residual heat. The end of the heat exchange pipes (5) is connected to a water storage device (6) to store the recovered water and realize its secondary use.

2. The return air waste heat circulation consolidation system for coal slime-based backfill materials according to claim 1, characterized in that, At least one relay fan (4) is installed at a predetermined distance along the length of the insulated pipe (2).

3. The return air waste heat circulation consolidation system for coal slime-based backfill materials according to claim 1, characterized in that, The air extraction device (1) includes: A filter screen (11) is detachably installed at the air inlet of the air intake device (1) to intercept solid particles in the airflow; A high-pressure spray gun (12) is detachably connected to the inside of the air inlet of the air-drawing device (1) and is used to clean the filter screen (11).

4. The return air waste heat circulation consolidation system for coal slime-based backfill materials according to claim 1, characterized in that, The gas splitting device (3) has an annular pressure balancing chamber (31), and one end of each heat exchange pipe (5) is connected to the annular pressure balancing chamber (31).

5. The return air waste heat circulation consolidation system for coal slime-based backfill materials according to claim 4, characterized in that, A perforated plate (32) is provided at the connection position between the annular pressure balance chamber (31) and the heat exchange pipe (5). The perforated plate (32) has several through holes for regulating the flow rate and distribution of airflow.

6. The return air waste heat circulation consolidation system for coal slime-based backfill materials according to claim 5, characterized in that, Each of the perforated plates (32) is connected to a regulating valve (33) on one side. The regulating valve (33) is used to control the number of passages in the perforated plate (32) to realize the airflow distribution to different heat exchange pipes (5).

7. The return air waste heat circulation consolidation system for coal slime-based backfill materials according to claim 1, characterized in that, The heat exchange pipe (5) is inclined in the lower middle part of the goaf filling body, and the inclination angle is 2 to 5°.

8. The return air waste heat circulation consolidation system for coal slime-based backfill materials according to claim 7, characterized in that, The outer diameter of the heat exchange pipe (5) is 1 / 8 to 1 / 10 of the height of the goaf.

9. The return air waste heat circulation consolidation system for coal slime-based backfill materials according to claim 1, characterized in that, A permeable trough (51) is provided at the upper part of the heat exchange pipe (5). The permeable trough (51) extends along the length of the heat exchange pipe (5). A layer of geotextile (53) is installed in the middle of the permeable trough (51). A layer of wire mesh (54) is installed above and below the geotextile (53).

10. The return air waste heat circulation consolidation system for coal slime-based backfill materials according to claim 9, characterized in that, The mesh size of the wire mesh (54) satisfies the formula: d net ≤k×d interception ; Where, d net Let d be the mesh size of the wire mesh (54), k be the safety margin factor, and take a value of 0.7 to 0.

9. interception The equivalent particle size of D30 particles in coal slime-based backfill materials.

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