Nitrogen filling in the well can not only increase the pressure in the well and increase the oil recovery, but also can be used as a buffer pad in the drill pipe measurement, completely avoiding the possibility of the mud propeller pressure squeezing the lower test tube column. Nitrogen is also used in downhole operations such as acidification, fracturing, hydraulic blowout, and hydraulic packer setting. Filling natural gas with nitrogen can reduce the calorific value. When crude oil is replaced, liquid nitrogen can be used to burn and inject materials at both ends to solidify and block them. It is safe, convenient and economical to use nitrogen gas in pressure transportation of pulverized coal.

2. Application in chemical industry

Nitrogen is the main raw material for ammonia synthesis. The nitrogen needed for ammonia synthesis does not need to be separated and purified, and comes directly from the air. In the production process of ammonia syngas, oxygen in the air reacts with hydrocarbon raw materials at high temperature. After transformation, decarbonization, methanation and other processes, a mixture of hydrogen and a small amount of methane, carbon monoxide and carbon dioxide is generated. Nitrogen and argon in the air do not participate in the reaction and directly enter the syngas, so as to obtain ammonia syngas dominated by hydrogen and nitrogen. In ammonia synthesis, oxygen, carbon monoxide and carbon dioxide are easy to make the synthesis catalyst toxic, and methane and argon are inert substances, which will reduce the synthesis efficiency. The use of liquid nitrogen washing process to purify the synthesis gas can prolong the service life of the catalyst and improve the efficiency of ammonia synthesis.

Nitrogen is also the main raw material for the synthesis of calcium cyanamide, sodium cyanide and silicon nitride.

High purity nitrogen can be used as auxiliary gas for polyethylene production. For example, a polyethylene production line with an annual output of 10 million tons requires 4,400 standard cubic meters of pure nitrogen per hour.

Using the chemical inactivity of nitrogen, nitrogen is filled in the reactor and storage tank of many flammable liquid substances, which not only protects the material from oxidation, maintains the quality of the product, but also ensures the safety and prevents the occurrence of combustion and explosion accidents.

3. Application in metallurgy industry

Nitrogen is mainly used as protective gas and purge gas in metallurgical industry. In the process of steel rolling and metal heat treatment, due to the protection of nitrogen, reduce the high temperature oxidation of metal, so that the surface is smooth. Filling the non-ferrous metal smelting furnace with nitrogen can reduce oxygen and temperature, reduce oxidation, and improve product purity. Purge molten steel with nitrogen to reduce the hydrogen content in steel and improve the strength of the product. 86% nitrogen is blown into the blast furnace when it is in operation, which can reduce coke consumption and prolong service life. Nitrided high speed tool steel can be produced by charging nitrogen in plasma electric arc furnace.

4. Application in electronic industry

In the electronic industry, the silicon wafers can be kept dry and clean by drying nitrogen. In the production process of large-scale integrated circuit, high purity nitrogen can be used as carrying gas, inert protective gas and packaging gas of chemical reaction gas.

5. Application in machining

Liquid nitrogen is used for over-matching or static matching of metal assembly, avoiding high temperature oxidation, can maintain the surface finish of parts. The wear life can be extended after processing the parts with liquid nitrogen bubble. Metal cutting with liquid nitrogen cooling, with long life, high surface finish advantages.

6. Application of science and technology

Nitrogen with high purity is commonly used as carrier gas in gas chromatography analysis. Liquid nitrogen is an important cold source in scientific instruments or experiments. For example, the single-crystal lithium detector of EDAX energy spectrometer needs to be stored and used at the temperature of liquid nitrogen. Many tests are carried out at low temperatures, which in most cases are provided by liquid nitrogen. Liquid nitrogen can be used as a cold trap, cold pump and cold source of low temperature superconductivity.

7. Application in food industry

Nitrogen is mainly used as protective gas in the food industry. For example, in the fruit and vegetable warehouse, nitrogen is filled to expel oxygen, inhibit the growth of mold and the generation and release of ethylene, delay the metabolism of fruits and vegetables, and lengthen the fresh-keeping period. In the storage of grain, filled with nitrogen, can delay aging, in a long time, maintain the flavor of new rice. With the acceleration of the pace of life, people pay more and more attention to fast food, filling the packaging container with nitrogen can extend the shelf life of these food. Fish, meat and other foods, frozen with liquid nitrogen, can achieve the effect of rapid freezing, prevent the water in the tissue to form glass, so that the tissue is not destroyed, reheating can maintain the original delicious taste.

8. Biological and medical applications

Nitrogen in the biological and medical fields, mainly or the use of liquid nitrogen low temperature nature and inert and non-toxic, is the ideal cold source. Liquid nitrogen has been widely used in the preservation of animal semen, human tissue and surgery.

9. Others

Liquid nitrogen also has some applications in the field of construction, such as the heat release of large volume of concrete when curing, internal cracks often appear and reduce the strength, using liquid nitrogen as a coolant, can greatly improve the strength of concrete. Liquid nitrogen plays a unique role in salvage operations. Liquid nitrogen creates pressure after gasification and can be used as a power source. Liquid nitrogen is also used in atmospheric condensation into clouds, space environment simulation, formation of low-temperature pneumatic channels, recovery of radioactive waste, removal of scale layer on metal surface, production of ceramic superconducting cables, crushing and recovery of waste rubber and plastic products, etc. Nitrogen can also be used as a fire extinguishing gas. Use nitrogen or nitrogen argon mixture alone to fill the bulb, can extend the life of the bulb.

In short, nitrogen is widely used in national economy and people's livelihood, which is closely related to human life, production activities and scientific experiments.