Flue gas adsorption-storage method based on goaf pressure-bearing multi-source solid waste filling

Abstract

The invention relates to the technical field of mine green filling and waste gas storage, and provides a flue gas adsorption-storage method based on goaf pressure-bearing multi-source solid waste filling. Aiming at the problems of surface subsidence of the goaf after coal mining and pollution of flue gas of the pithead power plant to the atmospheric environment, solid wastes generated in the coal mining process are used for performing nearby backfilling on the goaf, and meanwhile, harmful flue gas of the pithead power plant is subjected to adsorption-storage; and the filling cost is reduced, and meanwhile, the quality of air around a mining area is improved. Moreover, a'whole-section high multi-separation-layer continuous grouting 'method is adopted, so that'one hole with multiple purposes' and timely grouting in the dynamic development process of the separation layers are realized, the failure rate of the drill hole is reduced, and the service life of the drill hole is prolonged. Furthermore, a sensor installed in a to-be-filled area is utilized, intelligent real-time monitoring of the goaf roof contact condition and the flue gas sealing condition in the filling process is achieved, and the working efficiency is greatly improved.

Description

Technical Field

[0001] The present invention relates to the technical field of green mine filling and waste gas sealing, and in particular to a flue gas adsorption-sealing method based on pressurized multi-source solid waste filling in goafs. Background Art

[0002] With the development of social economy, the demand for coal has been increasing, resulting in a continuous increase in coal mining, accompanied by the generation of a large amount of solid wastes such as coal slag and coal gangue. The solid waste pollution caused by coal mining has become the main component of solid waste in my country. In addition, during the coal mining operation, after the underground coal or coal gangue is mined, there will be cavities or holes left, forming goafs. Goafs will cause the overlying rock strata to lose support, causing surface subsidence, which will affect safety and the environment.

[0003] In addition, the pit power plants around coal mines produce a large amount of coal-fired fly ash and coal-fired flue gas every year. The main components of the flue gas from power plants include N2, CO2, O2, SO x 、NO x And smoke, excessive emissions will not only endanger human health, but also seriously pollute the environment.

[0004] Therefore, how to deal with the solid waste generated by coal mining and the flue gas generated by pithead power plants, while filling the goaf, is an urgent problem that needs to be solved. Summary of the invention

[0005] In view of this, the present invention provides a flue gas adsorption-sealing method based on filling the goaf with pressurized multi-source solid waste. The present invention can not only fill the goaf with solid waste generated during coal mining, greatly reducing the surface subsidence caused by coal mining, but also seal the harmful flue gas generated by the pit power plant, reduce flue gas pollution, and improve air quality.

[0006] In order to achieve the above-mentioned object of the invention, the present invention provides the following technical solutions:

[0007] A flue gas adsorption-sealing method based on filling of pressurized multi-source solid waste in goaf includes the following steps:

[0008] Drilling is performed on the surface of the goaf to form grouting boreholes;

[0009] Mixing coal mine slag, coal gangue and fly ash to obtain filling aggregate;

[0010] The whole section high multi-detached layer continuous grouting method is adopted, and the filling aggregate, water and smoke are injected into the goaf and the overlying detached layer of the goaf through the smoke-slurry mixed injection system; the smoke-slurry mixed injection system includes an aggregate pipeline, a water injection pipeline, a smoke injection pipeline and a grouting pipe; the aggregate pipeline, the water injection pipeline and the smoke injection pipeline are all connected to the grouting pipe; the grouting pipe is connected to the grouting pump; the grouting pipe extends from the grouting borehole.

[0011] Preferably, the coal slag, coal gangue and fly ash are crushed and pulverized in sequence before use, and the particle size of the pulverized coal slag, coal gangue and fly ash is less than 100 μm.

[0012] Preferably, the mass ratio of the coal mine slag, coal gangue and fly ash is 1-2:1-2:1; the filling aggregate and water form slurry in the grouting pipe, and the water-to-solid ratio of the slurry is 0.6-1.3:1.

[0013] Preferably, the diameter of the grouting pipe is 110-130 mm; grouting holes are arranged on the wall of the grouting pipe, and the grouting holes are arranged along the length direction of the grouting pipe; the distance between adjacent slurry holes in the length direction is 0.2 m.

[0014] Preferably, the injection process is controlled by an intelligent grouting pumping system; the intelligent grouting pumping system includes a smoke-slurry automatic distribution system, an intelligent grouting pressure automatic control system, a goaf sensor real-time data collection feedback adjustment system and a grouting pipe automatic lifting system.

[0015] Preferably, the goaf sensor real-time data collection feedback adjustment system includes sensors; the sensors include filling body sensing sensors and smoke sensors; the sensors are installed on the two sides and the top plate of the goaf to be filled, and the sensors are used to perform real-time monitoring and information feedback on the goaf roof connection and smoke sealing conditions, and the intelligent grouting pumping system adjusts the pumping pressure of the injection process through the intelligent grouting pressure automatic control system based on the information obtained from the feedback.

[0016] Preferably, the whole section high multi-layer continuous grouting method comprises:

[0017] (1) Determine the theoretical grouting volume required for filling the goaf and each separation layer within 100 m of the overlying rock stratum above the goaf, and determine the length of the grouting pipe and the grouting pressure required to be provided by the grouting pump;

[0018] (2) Determine the theoretical flue gas storage capacity of the goaf to be filled and each layer within 100 m of the overlying rock strata above the goaf;

[0019] (3) Based on the theoretical grouting volume, grouting pipe length, grouting pressure and theoretical flue gas storage volume determined in steps (1) and (2), an intelligent grouting pumping system is used for control, and the goaf and each separation layer within 100 m of the overlying rock layer above the goaf are filled in sequence from bottom to top through a flue gas-slurry mixed injection system;

[0020] There is no time limit for step (1) and step (2).

[0021] Preferably, the grouting pressure in step (1) is controlled according to the grouting depth, and the grouting pressure increases by 2 to 3 MPa for every 10 m increase in the grouting depth;

[0022] The theoretical flue gas storage amount in step (2) is the sum of the chemical solidification storage amount and the physical adsorption storage amount.

[0023] Preferably, the step (3) specifically includes: first filling the goaf, and after the grouting volume and the smoke storage volume in the goaf reach the theoretical values, continuing to fill for 20 minutes, and then stopping the filling; lifting the grouting pipe to the abscission layer above the goaf for filling, and after the grouting volume and the smoke storage volume reach the theoretical values, continuing to fill for 20 minutes, and then stopping the filling, lifting the grouting pipe to the upper abscission layer and continuing to fill, until all abscission layers within 100m of the overlying rock layer above the goaf are filled.

[0024] Preferably, after all the separation layers within 100m of the overlying rock strata in the goaf are completely filled, the filling condition is detected by a drilling detection method, and secondary filling is performed when the solidity rate is less than 85%, until the solidity rate is greater than 85%.

[0025] The present invention provides a flue gas adsorption and sealing method based on filling of pressurized multi-source solid waste in goaf, comprising the following steps: drilling on the surface of the goaf to form a grouting borehole; mixing coal mine slag, coal gangue and fly ash to obtain filling aggregate; adopting a full-section high-multi-detached layer continuous grouting method, injecting the filling aggregate, water and flue gas into the goaf and the detached layer overlying the goaf through a flue gas-slurry mixed injection system; the flue gas-slurry mixed injection system comprises an aggregate pipeline, a water injection pipeline, a flue gas injection pipeline and a grouting pipe; the aggregate pipeline, the water injection pipeline and the flue gas injection pipeline are all connected to the grouting pipe; the grouting pipe is connected to a grouting pump; and the grouting pipe extends from the grouting borehole. The present invention recycles solid waste (coal slag, coal gangue) generated during coal mining, and gas-solid waste (fly ash, flue gas) discharged from pit-mouth power plants on site, and utilizes the filling body formed by coal solid waste to have a certain pressure-bearing effect in the goaf to fill the goaf, thereby greatly reducing the surface subsidence caused by coal mining; at the same time, the main components of the flue gas from the pit-mouth power plant are CO2, SO2, nitrogen oxides, etc., and the flue gas forms acids such as carbonic acid, sulfuric acid, and nitrous acid when it meets water, and the acids react with coal slag, coal gangue, and fly ash to form stable carbonates, sulfates, nitrates, etc., thereby realizing chemical solidification and sealing of the flue gas from the pit-mouth power plant; in addition, the surfaces of media such as coal pillars, coal slag, and coal gangue left in the goaf can also adsorb these flue gases, thereby realizing physical adsorption and sealing of the flue gas from the pit-mouth power plant.

[0026] The present invention utilizes a flue gas-slurry mixed injection system to simultaneously inject filling aggregate, water and flue gas, and utilizes the pressure during the flue gas injection process to coordinate the grouting pump, which can improve the fluidity of the filling slurry in the pipeline and improve the pumpability during the transportation process. In addition, the present invention adopts the "full-section high-multi-detached layer continuous grouting" method to achieve the filling of the goaf and multiple detached layers overlying the goaf through one borehole, realizing "one hole for multiple uses" and timely grouting during the dynamic development of detached layers, reducing the failure rate of drilling holes and extending the service life of the borehole. Furthermore, the present invention utilizes sensors installed in the area to be filled to realize intelligent real-time monitoring of the "top connection condition" and "smoke sealing" condition of the goaf during the filling process, and adjusts the grouting pressure according to the monitoring conditions, greatly improving the work efficiency.

[0027] In summary, the present invention aims to solve the problems of surface subsidence caused by goaf after coal mining and atmospheric pollution caused by flue gas from pit power plants. The solid waste generated in the coal mining process is used to backfill the goaf nearby, and the harmful flue gas from the pit power plant is "adsorbed and sealed". The filling cost is reduced while the air quality around the mining area is improved, which promotes the development of collaborative technology for green mining of my country's coal resources. BRIEF DESCRIPTION OF THE DRAWINGS

[0028] Figure 1It is a flow chart of a flue gas adsorption-storage method based on filling of pressurized multi-source solid waste in goaf in an embodiment of the present invention;

[0029] Figure 2 Schematic diagram of the grouting pipe used in the embodiment of the present invention; 1 is the grouting pipe, 2 is the grouting hole;

[0030] Figure 3 It is a schematic diagram of the full-section high-multi-layer continuous grouting method of the present invention. DETAILED DESCRIPTION

[0031] The present invention provides a flue gas adsorption-sealing method based on filling of pressurized multi-source solid waste in goaf, comprising the following steps:

[0032] Drilling is performed on the surface of the goaf to form grouting boreholes;

[0033] Mixing coal mine slag, coal gangue and fly ash to obtain filling aggregate;

[0034] The whole section high multi-detached layer continuous grouting method is adopted, and the filling aggregate, water and smoke are injected into the goaf and the overlying detached layer of the goaf through the smoke-slurry mixed injection system; the smoke-slurry mixed injection system includes an aggregate pipeline, a water injection pipeline, a smoke injection pipeline and a grouting pipe; the aggregate pipeline, the water injection pipeline and the smoke injection pipeline are all connected to the grouting pipe; the grouting pipe is connected to the grouting pump; the grouting pipe extends from the grouting borehole.

[0035] The present invention drills on the surface of the goaf to form a grouting borehole; the grouting borehole is connected to the goaf. In the present invention, the construction is carried out from top to bottom on the surface of the goaf, and the overlying rock strata are sequentially passed through to reach the goaf to form a grouting borehole; the overlying rock strata include curved sinking zones, fracture zones and collapse zones from top to bottom.

[0036] The present invention mixes coal slag, coal gangue and fly ash to obtain filling aggregate. In the present invention, the coal slag and coal gangue are both solid wastes generated in the process of coal mining; the fly ash is solid waste generated by the pit power plant around the coal mine; the coal slag, coal gangue and fly ash are preferably crushed and pulverized in sequence before use, and the particle size of the crushed coal slag, coal gangue and fly ash is preferably less than 100 μm; the mass ratio of the coal slag, coal gangue and fly ash is preferably 1-2:1-2:1, and more preferably 1:1:1.

[0037] After obtaining the filling aggregate, the present invention adopts the full-section high multi-detached layer continuous grouting method, and injects the filling aggregate, water and flue gas into the goaf and the detached layer overlying the goaf through the flue gas-slurry mixed injection system. In the present invention, the flue gas is the coal-fired flue gas generated by the pit power plant around the coal mine. In a specific embodiment of the present invention, it is preferred to establish a filling aggregate storage bin, a pit power plant flue gas storage bin and a water storage bin near the mining area, and connect the aggregate pipeline, the flue gas injection pipeline and the water injection pipeline to the filling aggregate storage bin, the pit power plant flue gas storage bin and the water storage bin respectively.

[0038] In the present invention, the flue gas-slurry mixed injection system includes an aggregate pipeline, a water injection pipeline, a flue gas injection pipeline and a grouting pipe; the aggregate pipeline, the water injection pipeline and the flue gas injection pipeline are all connected to the grouting pipe; the grouting pipe is connected to a grouting pump. In a specific embodiment of the present invention, the filling aggregate is introduced from the aggregate pipeline, the water is introduced from the water injection pipeline, and the flue gas is introduced from the flue gas pipeline, and finally all enter the grouting pipe; the filling aggregate and water form slurry in the grouting pipe, and the water-to-solid ratio of the slurry is preferably 0.6 to 1.3:1, and more preferably 0.8 to 1.2:1.

[0039] In the present invention, the diameter of the grouting pipe is preferably 110-130 mm, more preferably 120 mm; the wall of the grouting pipe is provided with grouting holes, and the grouting holes are arranged along the length direction of the grouting pipe; the distance between adjacent grouting holes in the length direction is preferably 0.2 m; the diameter of the grouting hole is preferably 10 mm; in a specific embodiment of the present invention, Figure 2 As shown, a pair of grouting holes is arranged every 0.2m in the length direction of the grouting pipe, and the pair of grouting holes is arranged opposite to each other on both sides of the grouting pipe wall; the length of the grouting pipe can be determined according to the actual filling depth and the conventional method in the field.

[0040] In the present invention, the injection process is preferably controlled by an intelligent grouting pumping system; the intelligent grouting pumping system preferably includes a smoke-slurry automatic distribution system, an intelligent grouting pressure automatic control system, a goaf sensor real-time data collection feedback adjustment system and a grouting pipe automatic lifting system; the smoke-slurry automatic distribution system automatically distributes the smoke and slurry required for filling each layer according to the calculated theoretical grouting volume and theoretical smoke storage volume; the intelligent grouting pressure automatic control system is used to adjust the grouting pressure; the goaf sensor real-time data collection feedback adjustment system is used to monitor and feedback the filling situation of the goaf; the grouting pipe automatic lifting system is used to adjust the depth of the grouting pipe.

[0041] In the present invention, the goaf sensor real-time data collection feedback adjustment system preferably includes sensors; the sensors preferably include filling body sensing sensors and smoke sensors; the sensors are installed at the two sides and the top plate of the goaf to be filled, and the sensors are used to monitor the goaf roof connection and smoke sealing conditions in real time and provide monitoring information feedback, and the intelligent grouting pumping system adjusts the pumping pressure of the injection process through the intelligent grouting pressure automatic control system based on the information obtained from the feedback, so that the goaf and the ground form a benign adjustment feedback system. In a specific embodiment of the present invention, when installing sensors on the two sides and the top plate of the goaf, it is preferred to install a sensor every 10m, and the filling body sensing sensor and the smoke sensor are arranged at intervals.

[0042] In the present invention, the whole section high multi-layer continuous grouting method preferably includes:

[0043] (1) Determine the theoretical grouting volume required for filling the goaf and each separation layer within 100 m of the overlying rock stratum above the goaf, and determine the length of the grouting pipe and the grouting pressure required to be provided by the grouting pump;

[0044] (2) Calculate the theoretical flue gas storage capacity of the goaf to be filled and each layer within 100 m of the overlying rock layer above the goaf;

[0045] (3) Based on the theoretical grouting volume, grouting pipe length, grouting pressure and theoretical flue gas storage volume determined in steps (1) and (2), an intelligent grouting pumping system is used for control, and the goaf and each stratum within 100 m of the overlying rock strata above the goaf are filled in sequence from bottom to top through a flue gas-slurry mixed injection system.

[0046] The present invention preferably determines the theoretical grouting volume required for each separation layer within 100m of the goaf to be filled and the overlying rock layer above the goaf, and determines the length of the grouting pipe and the grouting pressure required to be provided by the grouting pump. The separation layer will basically appear below the key layer. In the specific embodiment of the present invention, based on the geological survey, comprehensive drilling column chart, coal rock physical and mechanical parameters and other information provided by the mine, the number, depth and width of the key layer within 100m above the goaf are determined, and the volume of the separation layer is further obtained; in the present invention, the key layers are recorded as n1, n2, n3... layers in order from bottom to top; the depth of each key layer is recorded as h1, h2, h3..., and the width of each key layer is recorded as L1, L2, L3...; in order from bottom to top, each separation layer to be filled is recorded as separation layer 1, separation layer 2..., the volume of each separation layer is recorded as V1, V2, V3..., and the volume of the goaf is recorded as V; the present invention has no special requirements for the specific calculation method of the goaf and the volume of each separation layer, and it can be used by those skilled in the art.

[0047] In a specific embodiment of the present invention, after obtaining the volume of the goaf and each stratum overlying the goaf, the theoretical grouting volume required to fill the goaf and each stratum is calculated according to the volume of the goaf and each stratum, and the length of the grouting pipe and the grouting pressure required to be provided by the grouting pump are calculated. The present invention has no special requirements for the specific calculation method of the theoretical grouting volume, the length of the grouting pipe and the grouting pressure, and the method well known to those skilled in the art can be adopted; specifically, the grouting pressure is controlled according to the grouting depth, and the grouting pressure is preferably increased by 2 to 3 MPa, and more preferably increased by 2.5 MPa, for every 10m increase in the grouting depth. In a specific embodiment of the present invention, during the grouting process, it is initially in a non-pressure grouting state. As the grouting continues, the goaf and the overburden cracks are continuously enriched, so that the grouting state gradually changes to a pressurized grouting state. The orifice pressure of the grouting borehole is recorded as P 孔口 , the outlet pressure of the grouting pump is recorded as P 注浆泵 , the transport grouting pipeline resistance is recorded as P 管道阻力 , then P 注浆泵 >P 管道阻力 +P 孔口 .

[0048] In the specific embodiment of the present invention, the theoretical grouting volume of the goaf is recorded as M c , from bottom to top, the theoretical grouting amount of each separation layer to be filled is recorded as m1, m2, m3... In the present invention, the grouting amount specifically refers to the weight of the slurry formed by the filling aggregate and water.

[0049] The present invention preferably calculates the theoretical flue gas storage capacity of each separation layer within 100m of the goaf to be filled and the overlying rock layer above the goaf. In the present invention, the theoretical flue gas storage capacity is the sum of the chemical solidification storage capacity and the physical adsorption storage capacity. The chemical solidification storage capacity is recorded as Q1, the physical adsorption storage capacity is recorded as Q2, and the theoretical flue gas storage capacity is recorded as Q, then Q=Q1+Q2; the above theoretical flue gas storage capacity, chemical solidification storage capacity and physical adsorption storage capacity are all calculated based on the mass of flue gas.

[0050] The calculation method of theoretical flue gas storage capacity in the goaf is taken as an example to illustrate the calculation method of Q1 and Q2, where the calculation method of Q1 is as follows:

[0051] ① Test the temperature of the goaf to be filled, and collect and store the flue gas from the mine power plant near the mine;

[0052] ② Mix filling aggregate and water to prepare slurry, the amount ratio of filling aggregate and water is set according to the actual filling ratio; the mass of filling aggregate is recorded as q1;

[0053] ③ In the room, keep the temperature constant under the conditions of the goaf to be filled, and introduce the collected flue gas while stirring the slurry. After the flue gas and slurry fully react, stop stirring first and then stop introducing the flue gas;

[0054] ④ Allow the slurry to dry naturally after the reaction, and weigh it regularly to obtain its mass until its mass no longer changes, which is recorded as q2;

[0055] ⑤ The mass of flue gas from the mine mouth power plant that can be chemically solidified and sealed by unit filling aggregate is q c =q2-q1, that is, when the required filling aggregate mass is M1, the chemical solidification storage amount of flue gas is Q1=M1×q c .

[0056] Q2 is calculated as follows:

[0057] ① Sampling the coal pillars left in the goaf, and conducting simulated flue gas adsorption experiments on the coal samples and filling blocks (made of filling aggregates according to the proportion) under the same constant temperature and pressure conditions as the goaf, to obtain the flue gas adsorption mass of the coal samples left in the goaf per unit (denoted as q a ) and the mass of flue gas adsorbed by unit filling aggregate (denoted as q b );

[0058] ② When the mass of the coal pillar left in the goaf to be filled is M2 and the mass of the filling aggregate is M1, the physical adsorption amount of the flue gas is Q2 = M2 × q a +M1×q b .

[0059] According to the same method, the theoretical flue gas adsorption capacity of each layer above the adoption area is calculated. The q calculated by the above scheme can be directly used in the calculation. c ,q a and q b The value is that only the mass of the filling aggregate is replaced by the mass of the aggregate required for the separation layer. When calculating the theoretical smoke adsorption capacity of the separation layer, the value of M2 is 0. In the specific embodiment of the present invention, the theoretical smoke storage capacity of the goaf is recorded as Qc, and the theoretical grouting amount of each separation layer to be filled is recorded as Qc in order from bottom to top. i , Q ii , Q iii ….

[0060] After determining the theoretical grouting volume, grouting pipe length, grouting pressure and theoretical flue gas storage volume, the present invention uses an intelligent grouting pumping system for control according to the above-determined parameters, and fills the goaf and each separation layer within 100m of the overlying rock layer in the goaf in sequence from bottom to top through the flue gas-slurry mixed injection system. In the present invention, the filling specifically includes: first filling the goaf, and after the grouting volume and flue gas storage volume of the goaf reach the theoretical value, continue filling for 20 minutes, and then stop filling; lift the grouting pipe to the separation layer above the goaf for separation layer filling, and after the slurry volume and flue gas storage volume reach the theoretical value, continue filling for 20 minutes, then stop filling, lift the grouting pipe to the upper separation layer and continue filling, until each separation layer within 100m of the overlying rock layer of the goaf is filled.

[0061] In a specific embodiment of the present invention, it is preferred to first set the total amount of slurry injection required for filling (total amount of slurry = M c +m1+m2…), the amount of slurry injection required for the goaf and each stratum, the total amount of filled and sealed flue gas (total amount of sealed flue gas = Q c +Q i +Q ii …) and the amount of sealed flue gas required for the goaf and each stratum, and then set the pumping pressure in the intelligent grouting pressure automatic control system to start filling. After the goaf is filled, the grouting pipe is lifted to stratum 1 for filling through the grouting pipe automatic lifting system. After the stratum is filled, the grouting pipe is lifted to stratum 2 for filling through the grouting pipe automatic lifting system. In this way, the filling is repeated upward until the stratum below the key layer within 100m of the overlying rock stratum of the goaf is filled, and the filling and sealing is completed. Figure 3 It is a schematic diagram of the full-section high-multi-layer continuous grouting method of the present invention.

[0062] During the entire filling and sealing process of the present invention, the sensor real-time collection feedback adjustment system automatically adjusts the "smoke-slurry automatic distribution system" and the "intelligent grouting pressure automatic control system". The entire process does not require human intervention, which greatly improves work efficiency.

[0063] In the present invention, after the filling is completed, the filling condition is preferably detected by a drilling detection method, and when the solidity rate is less than 85%, a secondary filling is performed until the solidity rate is greater than 85%.

[0064] The following will be combined with the embodiments of the present invention to clearly and completely describe the technical solutions of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0065] Example 1

[0066] The operation flow diagram of this embodiment is as follows: Figure 1 As shown, the grouting pipe used is as follows Figure 2 shown.

[0067] Conduct on-site investigation of the target mining area, master the geological data of the target mining area, test the pressure, temperature and other parameters of the goaf, and calculate the total amount to be filled and the total amount of residual coal pillars in the mining area.

[0068] Based on the geological survey and other data provided by the mine, the number of key layers n (n1, n2...), depth h (h1, h2...) and width L (L1, L2...) within 100m above the goaf are determined, and the volume (V) of each stratum to be filled (v1, v2...) and goaf is further obtained; the grouting volume (M) of each stratum to be filled (m1, m2...) and goaf is further calculated, and the length of the grouting pipe and the grouting pressure provided by the grouting pump are determined; for every 10m increase in grouting pressure, the pumping pressure should be increased by 2.5MPa.

[0069] On-site sampling is carried out to collect slag, gangue, fly ash and flue gas from pit power plants in the target mining area, and the solid waste is crushed and ground, requiring the particle size after treatment to be less than 100μm. The ratio of water to filling aggregate is 4:6; (in the filling aggregate, the mass ratio of coal slag, gangue and fly ash is 1:1:1). Through indoor experiments, the total amount of flue gas storage and adsorption in each separation layer within 100m of the goaf and the overlying rock strata above the goaf is calculated, which includes two parts. The first part is the chemical solidification storage amount Q1, and the second part is the physical adsorption storage amount Q2. The specific calculation method of Q1 and Q2 will not be repeated.

[0070] According to the parameters determined above, field application is carried out as follows:

[0071] In the goaf, construction is carried out from top to bottom to form grouting holes.

[0072] Construct filling aggregate storage bins, pithead power plant flue gas storage bins and water storage bins near the mining area.

[0073] Filling body sensing sensors and flue gas sensors are installed every 10m between the two sides and the roof of the goaf to be filled, and connected to the "flue gas-slurry mixed injection system" on the ground to carry out intelligent real-time monitoring and feedback of the "roof connection condition" and "flue gas sealing of the pit mouth power plant" of the goaf during the filling process.

[0074] The aggregate pipeline, water injection pipeline and flue gas injection pipeline are connected with the grouting pipe (with a diameter of 120 mm) to form a "flue gas-slurry mixed injection system". In conjunction with the "intelligent grouting pumping system", the "full-section high-multi-layer continuous grouting method" is used to inject it into the goaf for filling. The details are as follows: According to indoor tests and theoretical analysis, the total amount of slurry for this filling (M c +m1+m2…), the amount of slurry injection required for the goaf and each stratum, and the total amount of flue gas filled and sealed (Q c +Q i +Q ii …) and the amount of sealed flue gas required for the goaf and each stratum, and then set the pumping pressure in the intelligent grouting pressure automatic control system to start filling. When the amount of slurry filled in the goaf reaches M c And the amount of sealed flue gas reaches Q c , after continuing to fill for 20 minutes, stop filling this layer, and lift the grouting pipe to the separation layer 1 for filling through the grouting pipe automatic lifting system. When the slurry volume in the separation layer reaches m1 and the sealed flue gas volume reaches Q1, continue to fill for 20 minutes, stop filling this layer, and lift the grouting pipe to the separation layer 2 for filling through the grouting pipe automatic lifting system. In this way, the filling is repeated upward until the separation layer below the key layer within 100m of the overlying rock stratum in the goaf is filled, and the filling and sealing are completed.

[0075] The above is only a preferred embodiment of the present invention. It should be pointed out that for ordinary technicians in this technical field, several improvements and modifications can be made without departing from the principle of the present invention. These improvements and modifications should also be regarded as the scope of protection of the present invention.

Claims

1. A flue gas adsorption and sealing method based on filling of pressurized multi-source solid waste in goaf, characterized in that: The following steps are involved: Drilling is performed on the surface of the goaf to form grouting boreholes; Mixing coal mine slag, coal gangue and fly ash to obtain filling aggregate; The whole section high multi-detached layer continuous grouting method is adopted, and the filling aggregate, water and smoke are injected into the goaf and the overlying detached layer of the goaf through the smoke-slurry mixed injection system; the smoke-slurry mixed injection system includes an aggregate pipeline, a water injection pipeline, a smoke injection pipeline and a grouting pipe; the aggregate pipeline, the water injection pipeline and the smoke injection pipeline are all connected to the grouting pipe; the grouting pipe is connected to the grouting pump; the grouting pipe extends from the grouting borehole.

2. The flue gas adsorption-storage method according to claim 1, characterized in that: The coal slag, coal gangue and fly ash are crushed and pulverized in sequence before use, and the particle size of the crushed coal slag, coal gangue and fly ash is less than 100 μm.

3. The flue gas adsorption-storage method according to claim 1, characterized in that: The mass ratio of the coal mine slag, coal gangue and fly ash is 1-2:1-2:1; the filling aggregate and water form slurry in the grouting pipe, and the water-to-solid ratio of the slurry is 0.6-1.3:

1.

4. The flue gas adsorption-storage method according to claim 1, characterized in that: The diameter of the grouting pipe is 110-130 mm; grouting holes are arranged on the pipe wall of the grouting pipe, and the grouting holes are arranged along the length direction of the grouting pipe; the distance between adjacent slurry holes in the length direction is 0.2 m.

5. The flue gas adsorption-storage method according to claim 1, characterized in that: The injection process is controlled by an intelligent grouting pumping system; the intelligent grouting pumping system includes a smoke-slurry automatic distribution system, an intelligent grouting pressure automatic control system, a goaf sensor real-time collection feedback adjustment system and a grouting pipe automatic lifting system.

6. The flue gas adsorption-storage method according to claim 5, characterized in that: The goaf sensor real-time data collection feedback adjustment system includes sensors; the sensors include filling body sensing sensors and smoke sensors; the sensors are installed on the two sides and the top plate of the goaf to be filled, and the sensors are used to perform real-time monitoring and information feedback on the goaf roof connection and smoke sealing conditions. The intelligent grouting pumping system adjusts the pumping pressure of the injection process through the intelligent grouting pressure automatic control system based on the information obtained from the feedback.

7. The flue gas adsorption-storage method according to claim 1, characterized in that: The whole section high multi-layer continuous grouting method comprises: (1) Determine the theoretical grouting volume required for filling the goaf and each separation layer within 100 m of the overlying rock stratum above the goaf, and determine the length of the grouting pipe and the grouting pressure required to be provided by the grouting pump; (2) Determine the theoretical flue gas storage capacity of the goaf to be filled and each layer within 100 m of the overlying rock strata above the goaf; (3) Based on the theoretical grouting volume, grouting pipe length, grouting pressure and theoretical flue gas storage volume determined in steps (1) and (2), an intelligent grouting pumping system is used for control, and the goaf and each separation layer within 100 m of the overlying rock layer above the goaf are filled in sequence from bottom to top through a flue gas-slurry mixed injection system; There is no time limit for step (1) and step (2).

8. The flue gas adsorption-storage method according to claim 7, characterized in that: The grouting pressure in step (1) is controlled according to the grouting depth. For every 10m increase in the grouting depth, the grouting pressure increases by 2-3MPa. The theoretical flue gas storage amount in step (2) is the sum of the chemical solidification storage amount and the physical adsorption storage amount.

9. The flue gas adsorption-storage method according to claim 7, characterized in that: The step (3) specifically includes: first, filling the goaf, and after the grouting volume and smoke sealing volume of the goaf reach the theoretical values, continuing to fill for 20 minutes, and then stopping the filling; lifting the grouting pipe to the abscission layer above the goaf for filling, and after the grouting volume and smoke sealing volume reach the theoretical values, continuing to fill for 20 minutes, and then stopping the filling, lifting the grouting pipe to the upper abscission layer and continuing to fill, until all abscission layers within 100m of the overlying rock layer above the goaf are filled.

10. The flue gas adsorption-storage method according to claim 9, characterized in that: After all the separation layers within 100m of the overlying rock strata in the goaf are filled, the filling situation is tested by drilling detection method. When the solidity rate is less than 85%, secondary filling is carried out until the solidity rate is greater than 85%.

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