Safe coal storage method

Abstract

The invention discloses a coal safety storage method which comprises the steps of layered compaction operation, construction of a coal slime closed isolation layer, spraying maintenance management, all-directional monitoring and monitoring, high-temperature emergency stripping treatment and pile turning and stack transferring treatment. Through double physical barriers of layered compaction and the coal slime closed isolation layer, the oxygen permeability is greatly reduced; the coal oxidation reaction is inhibited from the source in cooperation with humidity regulation and control of spraying maintenance; a monitoring mode of combining infrared thermal imaging and a temperature measurement probe rod is adopted, and manual inspection is matched, so that all-around and real-time monitoring of the surface layer and deep layer temperature of the coal pile is realized, high-temperature hidden danger inspection omission is avoided, and the safety early warning efficiency is improved. Through graded emergency measures of high-temperature stripping and pile turning and stack transferring, high-temperature hidden dangers of different degrees can be precisely handled, and meanwhile the processes of retesting, backfilling and the like are conducted; used equipment is conventional equipment in the field of coal storage, step design is standard, complex process transformation is not needed, and the method can be directly applied to coal storage of various large coal yards and coal sheds.

Description

Technical Field

[0001] This invention relates to the field of coal storage technology, specifically a method for safe coal storage. Background Technology

[0002] During storage, coal undergoes an oxidation reaction upon contact with air, releasing heat. If this heat cannot dissipate in time, the temperature of the coal pile will continue to rise, potentially leading to spontaneous combustion. Spontaneous combustion not only wastes coal resources but also produces toxic and harmful gases that pollute the environment and can even cause fires, explosions, and other safety hazards. Existing coal storage methods often rely solely on simple compaction and spraying techniques, which suffer from incomplete oxygen isolation, easy formation of oxidation hotspots, delayed monitoring of high-temperature hazards, and inadequate emergency response procedures, making it difficult to achieve long-term safe coal storage.

[0003] Therefore, those skilled in the art provide a method for the safe storage of coal to solve the problems mentioned in the background art. Summary of the Invention

[0004] The purpose of this invention is to provide a method for the safe storage of coal to solve the problems mentioned in the background art.

[0005] To achieve the above objectives, the present invention provides the following technical solution:

[0006] A method for safe coal storage includes the following steps:

[0007] 1) Layered compaction operation: After unloading coal, bulldozers are used to level and compact the coal pile, compressing the coal pile layer by layer to connect the pores. After compacting one layer, water spraying is carried out immediately to moisten the surface coal body. The coal spreading-compacting process is repeated, and water spraying is carried out simultaneously after compaction until the designed pile height is reached. After each layer is compacted, a level is used to check the flatness and remove local protrusions to avoid the formation of oxidation hot spots.

[0008] 2) Construction of coal slime sealing and isolation layer: After the top coal pile is compacted, a water collection pit is dug above the coal pile in a mesh structure. The water is continuously and evenly sprayed through a spraying system, so that the fine coal particles in the coal pile sink down with the water flow and fill the gaps between the coal blocks, forming a coal slime sealing and isolation layer on the surface. The water level in the water collection pit is kept stable so as to continuously replenish water to the coal slime layer and realize the dynamic repair of micro-cracks.

[0009] 3) Sprinkler curing management: By adjusting the frequency and volume of water spraying through the sprinkler system, the moisture content of stored coal is controlled within the preset range of 12% to 15%. The water infiltration from the water collection pit repairs the micro-cracks in the coal slurry layer caused by evaporation, and continuously ensures the isolation and sealing performance.

[0010] 4) Comprehensive monitoring: The monitoring system consists of an infrared thermal imaging camera and a three-section temperature probe to monitor the surface and deep temperatures of the coal pile. Combined with manual inspections and park security patrols, the frequency of inspections is increased for blind spots in the monitoring area.

[0011] 5) High-temperature emergency stripping treatment: When the local temperature of the coal pile is detected to rise to the 90℃ threshold, and conventional cooling measures such as increasing the spray volume and forced water injection are ineffective, an isolation zone is dug from the periphery of the high-temperature point, and the high-temperature coal body is gradually stripped towards the center and transferred to the temporary cooling area. After the temperature is retested and found to be qualified, it is backfilled and compacted.

[0012] 6) Turning over and stacking: When the coal pile that has been stripped at high temperature is heated to the threshold of 90℃ again, the entire pile is turned over and stacked to cool down. After the temperature reaches the standard, it is re-stacked according to the layered compaction and spraying requirements of step 1). It is then given priority for subsequent shipment.

[0013] As a further aspect of the present invention: In step 1), a large bulldozer is used for compaction, and the design height of the pile for layered compaction is 14-15m, with no more than 5 layers; the initial porosity of the loose coal pile is 35%-50%, and the porosity is precisely controlled to 20%-25% after compaction, thereby reducing the oxygen permeation rate by more than 60%.

[0014] As a further embodiment of the present invention: in step 2), the depth of the water accumulation pit is 0.3m, the distance between adjacent water accumulation pits is 10m, and they are evenly arranged in a mesh structure; the spraying duration is not less than 48 hours, the thickness of the coal slime sealing isolation layer is 5-10cm, the porosity is <10%, and the oxygen permeability is ≤0.005cm² / s.

[0015] As a further aspect of the present invention: in step 3), an intelligent spraying system is used to monitor the moisture content in real time and automatically adjust it to stabilize the moisture content of the stored coal in the optimal range of 13% to 14%. Under this moisture content condition, the coal pile oxidation rate is reduced by more than 90% compared with dry coal with a moisture content of <5%, and the surface temperature is reduced by 15 to 20°C compared with the ambient temperature.

[0016] As a further aspect of the present invention: In step 4), the infrared thermal imaging camera is arranged to cover the entire coal pile area according to standard, and the three-section temperature measuring probe is inserted into the coal pile at 2m intervals, with the insertion position rotated daily; manual inspection is carried out 4 times a day, and data is recorded at 12 preset temperature measuring points for each coal pile; the frequency of security patrols in the park is no less than 4 times a day, and 2 additional inspections are carried out for the northeast corner of the tipper and the blind spots near the wall of the adjacent area.

[0017] As a further aspect of the present invention: In step 5), the conventional cooling measures are to increase the spray volume and force water injection. If the temperature is still higher than 85°C after continuous treatment for more than 4 hours, it is ineffective. The isolation zone is excavated from 5m outside the high temperature point. First, a 0.3-0.5m thick layer of normal temperature coal is removed. After the temperature of the isolation zone is re-measured with a temperature probe and found to be ≤40°C and without any hidden high temperature points, the stripping is then advanced towards the center.

[0018] As a further aspect of the present invention: a loader is used for high-temperature stripping operations, with each stripping layer being 0.5 to 1 meter thick, prioritizing the removal of smoking and red-hot high-temperature coal bodies; during the stripping process, one inspector is assigned to monitor the temperature in real time with a temperature probe, inserting it deep into the coal pile to measure the temperature after each layer is stripped; if the temperature rises above 100°C, the operation is immediately stopped, and high-pressure spray cooling is activated; the operation is resumed only after the temperature drops below 50°C.

[0019] As a further step of the present invention: after the high-temperature coal body is transferred to the temporary cooling zone, it is spread out in layers with a thickness not exceeding 0.5m, and water is continuously sprayed for natural cooling; after the temperature inside the coal pile is ≤40℃, 3 to 5 points are randomly selected in the original high-temperature zone, and a 1.5m deep temperature probe is inserted for retesting. If the temperature of all points is stable at 35 to 40℃ and the fluctuation range is ≤2℃, it is considered that there are no residual high-temperature points. Then, the pit is backfilled with normal-temperature coal in layers and compacted.

[0020] As a further aspect of the present invention: In step 6), the turning and stacking is carried out with the full cooperation of a loader, and continuous spraying and cooling for more than 48 hours to reduce the temperature of the coal pile to below 50°C; when re-stacking, the layered compaction and spraying requirements of step 1) are strictly followed, and after stacking, it is included in the priority outbound plan, and all shipments are completed within 15 days unless there are special circumstances.

[0021] As a further aspect of the present invention: Step 1) By alternating the operation of layered compaction and spraying after compaction, the porosity of the coal pile is precisely controlled from 35% to 50% to 20% to 25%, forming the first dense oxygen isolation barrier, which together with the coal slime sealing isolation layer in Step 2) constitutes a dual protection system to block the diffusion of oxygen into the coal pile.

[0022] Compared with the prior art, the beneficial effects of the present invention are:

[0023] 1. This application significantly reduces oxygen permeability through a dual physical barrier of layered compaction and coal slime sealing and isolation layer. Combined with humidity control through spray curing, it inhibits coal oxidation reaction from the source, extending the coal spontaneous combustion period by more than 2 times compared to a single protection method. The application adopts a monitoring method combining infrared thermal imaging and temperature probes, along with manual inspection, to achieve comprehensive and real-time monitoring of the surface and deep temperatures of the coal pile, avoiding the omission of high-temperature hazards and improving the efficiency of safety early warning.

[0024] 2. This application uses graded emergency measures of high-temperature stripping and stacking to accurately handle high-temperature hazards of different degrees and prevent the spread of hazards. At the same time, through processes such as retesting and backfilling, it ensures that the treatment is thorough and there are no secondary hazards. The equipment used are all conventional equipment in the field of coal storage, and the steps are designed in a standardized manner. No complicated process modification is required. It can be directly applied to coal storage in various large coal yards and coal sheds, and has strong applicability. Detailed Implementation

[0025] The technical solutions in the embodiments of the present invention will be clearly and completely described below. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0026] In this embodiment of the invention, a method for safe coal storage includes the following specific steps:

[0027] 1. Layered Compaction Operation: After unloading the coal, a large bulldozer is used to level the surface of the coal pile, followed by compaction to compress the interconnected pores within the coal pile layer by layer. The initial loose coal pile porosity was 42%, which decreased to 23% after compaction, reducing the oxygen permeability rate by 65%. After the first layer of compaction is completed, a sprinkler system is activated to ensure the surface coal is moist. The coal laying-compaction process is then repeated, with a total of 5 layers laid, resulting in a final pile height of 14.8m. After each layer is compacted, a spirit level is used to check the flatness, and any protruding areas are removed to prevent the formation of oxidation hotspots.

[0028] 2. Construction of the Coal Slurry Sealing and Isolation Layer: After the top coal pile is compacted, a 0.3m deep water collection pit is dug every 10m in a mesh structure, ensuring uniform distribution of the pits. Water is continuously and evenly sprayed through a sprinkler system, causing fine coal particles in the coal pile to sink with the water flow, gradually filling the gaps between the coal blocks. After 48 hours of continuous spraying, an 8cm thick coal slurry sealing and isolation layer is formed on the surface of the coal pile. Testing shows that this coal slurry layer has a porosity of 8% and an oxygen permeability of 0.004cm² / s, effectively blocking the diffusion of oxygen from the surface to deeper layers. Simultaneously, the water level in the collection pits is maintained stable, providing a continuous water supply to the coal slurry layer.

[0029] 3. Sprinkler Curing Management: An intelligent sprinkler system regulates the frequency and volume of water spraying, and monitors the moisture content of the coal pile in real time to ensure it remains stable at 13%–14%. Under this moisture content condition, the oxidation rate of the coal pile is reduced by 92% compared to dry coal, and the surface temperature is 18°C ​​lower than the ambient temperature. When micro-cracks appear in the coal slurry layer due to moisture evaporation, water from the sump promptly seeps in, filling and repairing the cracks, ensuring the airtightness of the isolation layer.

[0030] 4. Comprehensive Monitoring: Three infrared thermal imaging cameras are deployed to cover the entire coal shed, scanning the surface temperature of the coal pile in real time. Simultaneously, three-section temperature probes are inserted into the coal pile at 2-meter intervals, with the probe positions rotated daily to record deep temperature data. Manual inspections are conducted four times daily, recording the temperature and coal movement at each of the 12 pre-set temperature measurement points in each coal pile. Security patrols are conducted five times daily in the park, with two additional patrols targeting blind spots such as the northeast corner of the tipper and near adjacent walls to prevent theft and ensure no security risks are missed.

[0031] 5. High-Temperature Emergency Stripping Treatment: At the end of the second month of storage, a temperature probe detected a local temperature rise of 92℃ in a coal pile. The spraying volume was immediately increased and forced water injection implemented. After 4 hours, the temperature remained at 88℃, and high-temperature stripping operations were initiated. Starting 5m from the periphery of the high-temperature point, a loader was used to remove the top 0.4m thick layer of normal-temperature coal to form an isolation zone. The temperature of the isolation zone was retested at 38℃. After confirming there were no hidden high-temperature points, stripping proceeded gradually towards the center, with each stripping layer being 0.8m thick, prioritizing the removal of locally smoking coal. During the stripping process, one inspector monitored the temperature in real time, inserting a temperature probe to check the internal temperature after each layer was stripped. When the third layer was stripped, the local temperature suddenly rose to 101℃. Operations were immediately stopped, and high-pressure spraying was activated for cooling. Operations resumed after the temperature dropped below 50℃. The stripped high-temperature coal was transported to a temporary cooling area, spread out in layers to a thickness of 0.5m, and allowed to cool naturally while continuously spraying water. After stripping the coal pile until the internal temperature dropped to 39℃, four points were randomly selected in the original high-temperature zone, and 1.5m deep temperature probes were inserted for retesting. The temperatures were all stable between 37 and 39℃, confirming that there were no residual high-temperature points. Subsequently, the pits were backfilled in layers with room-temperature coal and compacted.

[0032] 6. Turning over and repacking: When the coal pile was stored for 4 months, the local temperature was detected to rise to 91℃ again. Turning over and repacking was started. A loader was used to turn over and spread out all the coal in the pile. Spraying was continued to cool it down. After 48 hours, the temperature of the coal pile dropped to 48℃. The pile was then repacked using the layered compaction method. It was then included in the priority outbound plan and all shipments were completed within 15 days.

[0033] This embodiment achieves four months of coal storage without the risk of spontaneous combustion, and the coal pile temperature is always controlled within a safe range, effectively ensuring the safety of coal storage and reducing coal oxidation loss.

[0034] The above description is only a preferred embodiment of the present invention, but the scope of protection of the present invention is not limited thereto. Any equivalent substitutions or modifications made by those skilled in the art within the scope of the technology disclosed in the present invention, based on the technical solution and inventive concept of the present invention, should be covered within the scope of protection of the present invention.

Claims

1. A method of safe storage of coal, characterized in that, The method comprises the following steps: 1) Layered compaction operation: After unloading coal, a bulldozer is used to level and compact the coal pile, and the coal pile is compressed layer by layer to connect the pores. After the compaction of one layer, spraying and watering operation is immediately performed to make the surface layer of coal wet. The process of coal paving and compaction is repeated, and spraying is performed synchronously after compaction until the designed pile height is reached. After the compaction of each layer, a level gauge is used to detect the flatness, and local protruding parts are removed to avoid the formation of oxidation hot spots; 2) Construction of coal slime sealing and isolation layer: After the compaction of the top layer of the coal pile is completed, a water accumulation pit is dug on the coal pile according to a net structure, uniform spraying is continuously performed through a spraying system, fine coal particles in the coal pile sink to fill the gaps between coal blocks with water flow, a coal slime sealing and isolation layer is formed on the surface layer, the water level of the water accumulation pit is maintained to continuously supply water to the coal slime layer, and dynamic repair of micro cracks is realized; 3) Spraying maintenance management: The frequency and water quantity of spraying are controlled through the spraying system, the water content of stored coal is controlled in a preset range of 12% to 15%, the micro cracks of the coal slime layer due to evaporation are repaired by means of water infiltration of the water accumulation pit, and the sealing and isolation property is continuously ensured; 4) Comprehensive monitoring and monitoring: A monitoring system composed of an infrared thermal imaging camera and a three-section temperature measuring probe is used to monitor the surface layer and the deep layer of the coal pile, manual inspection and park security patrol are combined, and the inspection frequency of dead angle areas is increased; 5) High-temperature emergency stripping treatment: when it is detected that the local temperature of the coal pile rises to 90℃ threshold, after the conventional cooling measures of increasing the spraying quantity and forced water injection are invalid, an isolation belt is dug around the high-temperature point, the high-temperature coal body is gradually stripped to the center and transported to a temporary cooling area, and after the temperature is re-measured to be qualified, the isolation belt is backfilled and compacted; 6) Disposal of pile turning and pile unstacking: when the coal pile treated by high-temperature stripping is heated to 90℃ threshold again, the whole pile is turned and unstacked to be spread and cooled, and after the temperature reaches the standard, the pile is restacked according to the requirements of layered compaction and spraying of step 1), and subsequent transportation and shipment are preferentially arranged.

2. The method of claim 1, wherein, In step 1), a large bulldozer is used for compaction operation, the designed value of the layered compaction pile height is 14-15m, and the number of layers is not more than 5; the initial porosity of the loose coal pile is 35%-50%, and the porosity after compaction is accurately controlled to 20%-25%, so that the oxygen permeation rate is reduced by more than 60%.

3. The method of claim 1, wherein, In step 2), the depth of the water accumulation pit is 0.3m, the distance between adjacent water accumulation pits is 10m, and the water accumulation pits are uniformly arranged according to a net structure; the spraying duration is not less than 48 hours, the thickness of the formed coal slime sealing and isolation layer is 5-10cm, the porosity is less than 10%, and the oxygen permeation rate is less than or equal to 0.005cm² / s.

4. The method of claim 1, wherein, In step 3), an intelligent spraying system is used to monitor the water content in real time and automatically control the water content, so that the water content of stored coal is stably controlled in an optimal range of 13%-14%; under the condition of the water content, the oxidation rate of the coal pile is reduced by more than 90% compared with dry coal with a water content less than 5%, and the surface layer temperature is reduced by 15-20℃ compared with the ambient temperature.

5. The method of claim 1, wherein, In step 4), the infrared thermal imaging camera is arranged according to the standard of full coverage of the coal pile area, and the three-section temperature measuring probe is inserted into the coal pile at an interval of 2m, and the probe position is changed daily; Artificial inspection is carried out 4 times a day, and 12 preset temperature measuring points are recorded for each coal pile. The frequency of security patrol in the park is not less than 4 times a day, and 2 additional inspections are added in the northeast corner of the tipping machine and near the adjacent area wall.

6. The method of claim 1, wherein, In step 5), the conventional cooling measures are to increase the amount of spraying and forced water injection, and the treatment is continued for more than 4 hours. If the temperature is still higher than 85℃, it is invalid. The isolation zone is excavated from 5m outside the high temperature point. First, remove the 0.3-0.5m thick surface layer of normal temperature coal. After the temperature in the isolation zone is measured to be ≤40℃ and there is no hidden high temperature point, the stripping is pushed to the center.

7. A method of safe storage of coal as claimed in claim 6 wherein, The high-temperature stripping operation is carried out by a loader, with a stripping thickness of 0.5-1m each time, and the smoking and red high-temperature coal body is removed first. During the stripping process, a tester holds a temperature probe to monitor in real time. After each layer is stripped, the temperature is measured in the deep layer of the coal pile. If the temperature rises above 100℃, the operation is immediately stopped, the high-pressure spraying cooling is started, and the operation is resumed after the temperature drops below 50℃.

8. The method of claim 6, wherein, After the high-temperature coal is transported to the temporary cooling area, it is spread in layers with a thickness of not more than 0.5m, and water is continuously sprayed for natural cooling. After the internal temperature of the coal pile is ≤40℃, 3-5 random points are selected in the original high-temperature area, and a 1.5m deep temperature probe is inserted for re-measurement. If the temperature of all points is stable at 35-40℃ and the fluctuation amplitude is ≤2℃, it is a non-residual high-temperature point. Then, the normal temperature coal is used to backfill the pit in layers and compacted.

9. The method of claim 1, wherein, In step 6), the loader is used throughout the process of turning and dumping, and the spraying cooling is continued for more than 48 hours to reduce the temperature of the coal pile to below 50℃. When the pile is re-stacked, the requirements of step 1) for layering and compaction and spraying are strictly followed. After the pile is stacked, it is included in the priority delivery plan, and all shipments are completed within 15 days without special circumstances.

10. The method of claim 1, wherein, In step 1), through the alternating operation of layering and compaction and spraying after compaction, the porosity of the coal pile is precisely controlled from 35%-50% to 20%-25%, forming the first dense oxygen isolation barrier. Together with the closed isolation layer of coal slurry in step 2), it forms a double protection system to block the diffusion of oxygen into the coal pile.