Core application areas

（1） Industrial manufacturing field

Chemical safety protection: used for inert protection of reaction vessels and storage tanks, by replacing air to reduce oxygen concentration to below 2% (highly flammable media such as hydrogen should be ≤ 1%), to prevent the formation of explosive mixtures; ​

Metallurgical processing protection: Nitrogen gas with a purity of ≥ 99.9% is introduced during stainless steel heat treatment, which improves the surface smoothness by 2-3 levels and reduces the scrap rate from 5% to below 1%; When welding aluminum profiles, nitrogen is used to isolate the air, reducing the porosity of the weld seam by 90%; ​

Machinery and Energy: Nitrogen injection underground in coal mines to suppress coal seam spontaneous combustion requires approximately 500000 cubic meters of nitrogen injection per 10000 tons of coal seam; ​

（2） Food and pharmaceutical industry

Food preservation: Food grade nitrogen (purity ≥ 99.5%) is used for modified atmosphere packaging. When the oxygen content of berry fruits is controlled to be less than 2%, the preservation period is extended to 30 days, and the incidence of nut oxidation and halitosis is reduced from 12% to 0.5%; After nitrogen filled packaging of puffed food, the rate of oil spoilage is reduced by 50%, and the shelf life is extended from 6 months to 18 months; ​

Medical support: Pharmaceutical grade nitrogen (purity ≥ 99.99%) is used for filling injection ampoules, extending the shelf life of penicillin and other drugs from 24 months to 36 months; When biological samples are frozen and stored, nitrogen and liquid nitrogen are combined to maintain an inert environment, resulting in a vaccine efficacy rate of over 95%. ​

（3） Electronics and Research Fields

Electronic manufacturing: Semiconductor wafer processing requires 6N grade high-purity nitrogen (99.9999%), ambient oxygen concentration ≤ 10ppm, dew point ≤ -60 ℃, to prevent wafer surface oxidation defects and improve chip yield by 12%; Nitrogen protection during LED soldering reduces the virtual soldering rate from 8% to 0.3%;

Low temperature and scientific research: Liquid nitrogen is used as a refrigerant (temperature -196 ℃) for superconducting material testing and biological sample freezing; In the quantum laboratory, blowing nitrogen through optical components can reduce water vapor interference and improve experimental accuracy by 20%. ​

（4） Daily life and environmental protection

Environmental governance: Nitrogen is added in the aeration process of sewage treatment, dissolved oxygen is maintained at 2-4mg/L, and COD removal rate reaches 85%; Nitrogen injection in eutrophication treatment of lakes improves the anaerobic environment of water bodies, and the mortality rate of algae reaches 90%; ​

Home applications: Nitrogen filling for grain storage and pest control, replacing chemical agents to reduce mold growth rate from 15% to 1%; Storing wine with nitrogen to isolate the air slows down tannin oxidation by 60%. ​

Safety regulations and operating guidelines

（1） Storage requirements

Environmental control: cool and ventilated warehouse (temperature ≤ 30 ℃), safe distance from flammable materials and reducing agents ≥ 5 meters, equipped with explosion-proof lighting and mechanical ventilation equipment (air exchange rate ≥ 10 times/hour); ​

Container standard: Use seamless steel cylinders (working pressure 12-15MPa), inspected every 5 years; Liquid nitrogen storage tanks need to be regularly checked for vacuum degree to prevent overpressure caused by insulation failure. ​

（2） Transportation standards

UN classification: Non flammable and non-toxic gases (category 2.2), transportation vehicles labeled with “inert gas” signs, equipped with self-contained breathing apparatus and leak sealing equipment; ​

Special requirements: Steel cylinders must be fixed to prevent tipping and avoid impact; Liquid nitrogen transport vehicles need to be equipped with low-temperature protection devices to avoid densely populated areas and heat sources. ​

（3） Operation and Emergency Response

Operation taboos:

Before working in a confined space, check the oxygen concentration (≥ 19.5% for entry) and wear a portable oxygen detector; ​

During the replacement operation, the nitrogen flow rate should be ≤ 5m/s. Oxygen concentration should be detected every 10 minutes until it meets the process requirements (usually ≤ 5%) before operation can begin; ​

It is prohibited to use a filter mask to enter the leakage area, and a self-contained breathing apparatus (SCBA) must be used. ​

Leakage handling:

Immediately report to the police and designate a warning zone of ≥ 50 meters, turn on all ventilation equipment, and evacuate personnel in the upwind direction; ​

Close the upstream and downstream valves in case of pipeline leakage, tighten the main valve clockwise in case of cylinder leakage, and seal the valve with a special cylinder cap when it is damaged; ​

Continuously monitor oxygen concentration until it recovers to 20% -21% before lifting the alert. ​

Emergency measures:

Immediately transfer oxygen deficient individuals to fresh air and administer oxygen (flow rate 2-4L/min); ​

For those who have stopped breathing, perform cardiopulmonary resuscitation (chest compressions at a frequency of 100-120 times/minute), simultaneously dial 120 and explain “nitrogen asphyxia”. ​

（4） Disposal of waste

The residual gas in the steel cylinder can be emptied in a ventilated area without a fire source. Damaged steel cylinders should be disposed of by professional institutions as scrapped pressure vessels, and unauthorized cutting and modification are prohibited.