Coal Spontaneous Combustion Control in Storage & Transportation
In the process of coal storage and transportation, the industry is plagued by prevalent pain points such as prominent spontaneous combustion risks, uncontrolled coal quality, surging environmental protection pressure and accumulated invalid costs, with personalized challenges in different scenarios:
(1) Dynamically Circulated Coal: Unfixed coal storage cycles and extended stockpiling due to power grid peak regulation, a high proportion of blended easily spontaneous combustion coal types. Traditional water-based fire extinguishing tends to cause re-ignition, coal quality damage and frequent environmental problems.
(2) Long-term Stored Coal: Storage cycles far exceeding the natural ignition period of coal, rapid oxidative heating inside coal piles, great difficulty in disposal after spontaneous combustion, accompanied by calorific value loss and toxic gas emission.
(3) Coal Transportation Chain: Rapid temperature rise in the enclosed space of carriages/cargo holds, difficult early warning of spontaneous combustion and fire extinguishing disposal, environmental pollution caused by flue gas diffusion, ambiguous definition of liabilities for spontaneous combustion, as well as frequent problems such as shipping/train delays and cargo damage claims.
The core industrial demands focus on ensuring continuous supply, controlling fuel/cargo damage costs, stabilizing coal quality, avoiding safety and environmental risks, abiding by transportation timeliness, and realizing long-term stable storage and safe, efficient transportation of coal.
1. Core Solution: Integrated Prevention of Spontaneous Combustion and Coal Quality Management
With maintaining coal quality stability as the core of spontaneous combustion prevention and control, this solution achieves flame retardation and loss reduction, intelligent prevention and control, and environmental compliance through the whole-process technical means of monitoring-prevention-governance, and simultaneously attains the dual goals of fire prevention and quality preservation, applicable to all scenarios of dynamic circulation, long-term storage and coal transportation.
1.1 Whole-process Technology for Coal Spontaneous Combustion Prevention and Coal Quality Management in Storage
A 9-step standardized governance process is implemented for the coal storage link, blocking coal-oxygen contact in an all-round way and inhibiting oxidative heating from basic preparation to real-time monitoring to ensure stable coal quality:
(1) Overall Shaping of Coal Piles: Trim the roads on coal piles and level the top to create basic conditions for subsequent construction.
(2) Spraying of Coal-Oxygen Inhibitor: Spray on the shallow surface of coal piles to passivate active groups, raise the critical temperature of coal oxidation and increase the difficulty of oxidation.
(3) Spraying of Dual-Phase Change Colloid Material: Fixed-point spraying in high-temperature open fire areas for rapid cooling and oxygen isolation; mobile intelligent spraying devices can be used for short-term circulated coal.
(4) Leveling with Slope Compactor: Level and compact the slopes of coal piles with the YSBZ slope compaction device to reduce the internal porosity of coal piles.
(5) Arrangement of Wireless Ad Hoc Network Terminals: Evenly arrange at the middle and lower parts of coal piles to realize real-time monitoring of discrete points of coal temperature and CO concentration.
(6) Spraying of Sealing Material Ⅰ: Fill the surface cracks of coal piles to form a complete integrated structure and block oxygen penetration through cracks.
(7) Spraying of Sealing Material Ⅱ: Form a dense protective layer on the coal surface to isolate oxygen contact from the surface layer.
(8) Inert Gas Filling: Form a micro-positive pressure space between the sealing layer and coal mass to further block coal-oxygen contact and strengthen the oxygen isolation effect.
(9) Real-time Online Monitoring: Real-time monitor coal temperature and CO content through the system composed of terminals, repeaters, receivers and upper computers, and supplement inert gas on demand to realize dynamic prevention and control.
1.2 Customized Solutions for Different Scenarios
(1) Solution for Dynamically Circulated Coal
Applicable Scenarios: Scenarios with flexible coal storage cycles and a high proportion of easily spontaneous combustion coal types, such as peak-regulating power plants and coal chemical enterprises.
Solution Ideas:
Flame retardation and loss reduction (compaction for oxygen isolation + sealing technology to block oxidation and reduce calorific value loss) → Intelligent prevention and control (wireless ad hoc network monitoring system: monitor temperature/CO gas and give early warning of spontaneous combustion; mobile intelligent spraying device: cool down and isolate oxygen to reduce the cost and risk of manual disposal) → Environmental compliance (efficient and intelligent disposal methods to control spontaneous combustion flue gas and curb dust and foul gas emission).
Core Value: Extend the coal storage cycle to more than 2 months, solve the dilemma of coal storage time limit for peak-regulating power plants, eliminate environmental problems caused by spontaneous combustion, and reduce the cost of manual disposal.
(2) Solution for Long-term Stored Coal
Applicable Scenarios: Scenarios with storage cycles exceeding the natural ignition period, such as strategic coal reserve bases, emergency coal storage yards of power plants and long-term coal stockpiling at ports.
Solution Ideas: Adopt advanced and reliable comprehensive coal spontaneous combustion prevention and control technologies to inhibit coal spontaneous combustion, extend the natural ignition period of coal, thus avoiding invalid passive rotation and supporting the long-term strategic storage of coal resources.
Core Value: Extend the safe storage cycle of easily spontaneous combustion coal types to more than 6 months without any spontaneous combustion signs throughout the process, ensure the stable calorific value of coal quality, and avoid the increase of coal storage costs caused by invalid passive rotation.
(3) Solution for Coal Transportation Chain
Applicable Scenarios: Railway, waterway and highway coal transportation, especially long-distance transportation scenarios such as intra-river transshipment at ports and international maritime transportation.
Implementation Ideas: Source oxygen inhibition (blend inhibitors synchronously during loading to reduce the oxidation activity of coal) → Intelligent monitoring (arrange wireless monitoring grids in carriages/cargo holds to locate the overall status of stored coal and accurately capture the abnormal critical value of CO) → Surface oxygen sealing (spray sealing materials to form a dense oxygen isolation layer on the coal surface and continuously block oxidation reactions) → Pollution prevention and control (implement overall disposal measures for coal spontaneous combustion in transportation, block flue gas emission and curb the diffusion of toxic gases).
Core Value: Achieve zero spontaneous combustion accidents during transportation, block the emission of spontaneous combustion flue gas, reduce cargo damage claims and delay fines, and ensure the stable and smooth operation of the coal supply chain.
2. Core Technology and Equipment System
Ji’an Technology has built a technology and equipment system centered on intelligent monitoring and early warning, fire prevention and extinguishing materials, intelligent equipment and emergency disposal. All technologies have been verified by the industry, some of which have reached the international leading level. They are non-toxic, non-corrosive, have no impact on coal quality, and take both safety and environmental protection into account.
2.1 Intelligent Monitoring and Early Warning System
1. Bundle Tube Gas Sampling Device (MZQC6/6)
- Core Function: Realize real-time monitoring of gases such as CO, CO₂, O₂, CH₄, C₂H₂, C₂H₄ as well as temperature, humidity and pressure difference, and early forecast of fire conditions.
- Technical Features: 6-channel sampling, local/remote dual control, automatic switching of circulating air extraction, high precision of continuous monitoring by sensors, self-check for faults, visual flow rate, and long single-channel sampling distance.
- Early Warning Method: Acoustic and optical dual early warning by upper computer, providing scientific data basis for spontaneous combustion prevention and control.
2. Wireless Ad Hoc Network Monitoring System
- Core Function: Realize low-cost real-time monitoring and early warning of discrete points of temperature and CO concentration in coal piles/carriages/cargo holds.
- Technical Features: Small size, easy installation, no complicated wiring, adapt to the mobile and decentralized monitoring needs of storage and transportation scenarios, and accurately capture the precursors of spontaneous combustion.
2.2 Core Fire Prevention and Extinguishing Materials
(1) Coal-Oxygen Inhibitor
Its core function is to passivate the activity of coal mass and cut off coal-oxygen contact from the source. At the same time, it can also play a role in dust suppression and loss prevention, reducing weight loss during coal transportation and storage. As an off-white liquid, it has no adverse effect on coal quality, can effectively improve the activation energy of coal mass and raise the critical temperature of all stages of oxidation, essentially inhibiting coal oxidative spontaneous combustion. It has the dual practical effects of fire prevention and dust suppression, and can be widely used in shallow surface spraying of coal piles, blending during transportation loading, belt conveying and other links.
(2) Dual-Phase Change Colloid Material
It features two core functions of rapid cooling and oxygen isolation. Meanwhile, it can be compounded with mud or fly ash slurry to effectively solidify the slurry, prevent pipeline blockage, and improve grouting efficiency and quality. As a white powder, it has fast cooling speed, excellent oxygen isolation performance and lasting effect after compounding with slurry, and outstanding thermal stability. It can be safely used even in open fire areas without the risk of water gas explosion, and is mainly applicable to spontaneous combustion governance scenarios such as fixed-point spraying in high-temperature open fire areas and cooling grouting inside coal piles.
(3) Prater Fire Extinguishing Material
Designed specifically for the precise treatment of point-like high-temperature areas, it accurately controls water at high-temperature areas for heat absorption and cooling through its water absorption and retention characteristics, minimizing the impact on the surrounding coal mass. Adopting an A/B two-component compound form, it has excellent water retention after gel formation, with lasting cooling effect and no easy loss. The construction process is simple and convenient without the need for large-scale equipment to excavate coal piles. It can quickly dispose of point-like high-temperature areas in coal piles and is also suitable for rapid fire extinguishing operations in the early stage of spontaneous combustion.
(4) New Sealing Material
Its core role is to form a dense oxygen isolation film on the coal surface, achieving efficient oxygen isolation while also playing the roles of wind and dust prevention and rain erosion resistance, providing multiple protections for coal mass. As an off-white liquid, it can form a film with a thickness of 2-5mm after spraying. The film layer has good ductility and strength, strong damage resistance, low dosage, high adaptability of effective components, no impact on coal quality, and lasting oxygen isolation and dust prevention effects. It is mainly used for full-surface spraying of coal piles, surface oxygen sealing of transported coal and other scenarios.
2.3 Intelligent Construction and Compaction Equipment
(1) YSBZ Slope Compactor
- Core Function: Compact and level the slopes and tops of coal piles to reduce internal porosity and lay a foundation for oxygen isolation protection.
- Technical Features: Wireless remote control operation, with operators away from the operation area for high safety and efficiency; the roller can be weighted by quantitative water addition to adapt to different coal pile working conditions; driven by a double-drum hoist, with low failure rate and convenient maintenance.
(2) Mobile Intelligent Spraying Equipment for Sealing Materials
- Core Function: Realize all-round and uniform spraying of new sealing materials to achieve dead-angle-free oxygen isolation on the coal pile surface.
- Technical Features: Unmanned remote control with real-time viewing of spraying effect through high-definition images; built-in material loading and unloading mechanism, liftable to adapt to complex positions such as pile tops, with high operation efficiency and reduced labor intensity of operators.
2.4 Emergency Disposal Equipment: Emergency Fire Prevention and Extinguishing Device
- Core Function: Integrate batching, conveying, spraying/grouting in one, meeting the dual needs of high-temperature fire extinguishing and oxygen isolation prevention.
- Technical Features: Integrated whole assembly, flexibly towed by loaders/excavators with convenient movement and fast response; modular and intelligent design with constant proportion automatic batching for precise ingredient preparation; built-in supercharging equipment with strong power, adapting to on-site emergency disposal.
The integrated solution for coal spontaneous combustion prevention and coal quality management in storage and transportation is applicable to the whole chain of dynamic circulation, long-term storage and coal transportation with customized strategies for all scenarios. It builds a full-process prevention and control system of monitoring-prevention-governance, integrating spontaneous combustion prevention and coal quality management to achieve dual effects. Equipped with a complete set of technical equipment including intelligent monitoring, fire prevention and extinguishing materials, intelligent construction and emergency disposal, the materials are environmentally friendly, non-toxic and have no impact on coal quality, while the intelligent equipment supports remote/unmanned operation to reduce costs and improve efficiency. Through multiple protection measures, it achieves a lasting and stable prevention and control effect, greatly extends the coal storage and transportation cycle, creates a systematic solution for the whole storage-transportation chain, and fundamentally solves the industrial pain points such as spontaneous combustion, uncontrolled coal quality and excessive environmental indicators.
