How is PSA nitrogen generator used for fire suppression in the coal industry?
Coal is an important energy pillar in China, and the safety production industry is the core of development. In coal mining, coal is a major safety hazard. Traditional fire suppression methods such as water flooding and grouting are not only inefficient but also prone to causing disasters, being complex and difficult. With the increasingly mature technology, a more efficient, environmentally friendly, controllable, and safe technology – PSA (Pressure Swing Adsorption) nitrogen fire suppression technology, has become a substitute for use in the field of fire prevention and suppression in the coal industry.
I. Potential dangers of coal spontaneous combustion
Coal naturally undergoes a slow oxidation reaction due to its porous structure, which releases heat underground, causing the coal temperature to rise to approximately (60-80℃), ultimately triggering a fire. These not only waste resources but also produce a large amount of toxic gases, directly threatening the lives of miners, and may trigger major accidents such as gas explosions, posing a threat to the safety of coal mines.
PSA nitrogen generator
II. Principle and advantages of PSA nitrogen generator
Working process
Compression and adsorption: The air compressor compresses and purifies the ambient air and sends it into the adsorption tower filled with carbon molecular sieves. The carbon molecular sieves have a priority adsorption ability for oxygen, and within a short period of time, a large amount of oxygen is adsorbed in the sieve pores.
Output nitrogen: At this time, the unadsorbed nitrogen (with a purity of up to 95%-99.9%) flows out from the top of the adsorption tower and becomes the product gas, which is transported to the required location.
Pressure reduction and desorption: When the carbon molecular sieves in the adsorption tower are saturated with oxygen, the system will automatically switch to another adsorption tower to continue working, and at the same time, this saturated tower will be depressurized. The pressure reduction causes the adsorbed oxygen to be desorbed from the molecular sieves, and it is discharged as waste gas.
Cycle regeneration: Through the alternating operation of two or more adsorption towers, a PSA nitrogen generator can achieve continuous and stable production of high-purity nitrogen.
Advantages of using PSA nitrogen generator for coal mine fire suppression:
Safe inertization, no damage to production
Nitrogen, as an inert gas, can dilute the oxygen to a combustion critical value (usually <10%) below, fundamentally suffocating the fire source. This process does not damage equipment, block tunnels, or cause secondary harm, facilitating rapid post-disaster resumption of production.
Efficient penetration, no dead corners for fire suppression
Nitrogen, with its excellent fluidity and penetration ability, can penetrate into abandoned areas, coal fissures, and other concealed spaces, precisely extinguishing fire sources that traditional media (such as water, slurry) cannot reach.
Combination of prevention and control, preventing problems before they occur
This technology has both fire suppression and prevention dual functions. Continuously injecting nitrogen into the hazard area can establish an inert environment, suppressing coal oxidation from the source, achieving “preventing problems before they occur”.
III. Key Technical Guarantees for Fire Extinguishing by PSA Nitrogen Generator
To ensure the effectiveness and safety of fire extinguishing, the PSA nitrogen generator needs to achieve three technical guarantees: Firstly, raw gas purification. Given the characteristics of mine air, which contains dust, water vapor and gas, it is best to install high-efficiency filters with high filtration accuracy and adsorption-type dryers to control the inlet gas dew point below -40℃, preventing molecular sieves from getting damp and losing their effectiveness; Secondly, pressure and flow regulation. Equip with a variable frequency control system, automatically adjust the nitrogen injection pressure (usually 0.3-0.6 MPa) according to the pressure in the fire zone to prevent gas outflow; Thirdly, safety interlock protection. When abnormal pressure in the nitrogen injection pipeline or gas concentration exceeds the limit (＞1%) is detected, the system will automatically stop, cut off the pipeline and activate the alarm.
In summary, the PSA nitrogen technology, with its efficient, safe and environmentally friendly characteristics, has become a decisive force in improving the safety level of coal mining. It is not only a direct means of fighting fires, but also a fundamental guarantee for protecting the lives of miners and ensuring the stable supply of national energy. In the future of high-quality development of the industry, it will play an indispensable and crucial role.
