Uses and common preparation methods of nitrogen
First, the nature of nitrogen
Nitrogen, under normal conditions, is a colorless, tasteless, odorless gas and is usually non-toxic. Nitrogen accounts for 78.12% of the total atmosphere (volume fraction). At normal temperature, it is a gas. At standard atmospheric pressure, it becomes a colorless liquid when it is cooled to -195.8℃. When it is cooled to -209.86℃, liquid nitrogen becomes a snow-like solid. Usage: chemical synthesis (synthetic nylon, acrylic fiber, synthetic resin, synthetic rubber and other important raw materials), automobile tires (nitrogen can effectively reduce the noise of tires, prolong the service life of tires). Because nitrogen is chemically inert, it is often used as a protective gas, such as melon, fruit, food, and light bulb filling gas.
Two, the use of nitrogen
Nitrogen in metallurgy, chemical industry, light industry, electronics and other departments, as feedstock gas, protective gas, replacement gas and sealing gas. Liquid nitrogen products are also widely used in food frozen, vegetables and fruits preservation. It is also widely used in agriculture and animal husbandry, such as insecticidal grain storage, frozen storage of semen of superior livestock, etc. Is the constituent of proteins in plants and animals.
With the progress of science and technology and the development of economy, the application scope of nitrogen is expanding day by day.
Take advantage of the inertia of nitrogen
Metal thermal processing: bright quenching, bright annealing, carburizing, carbonitriding, soft nitriding and other nitrogen based atmosphere heat treatment of nitrogen source, welding and powder metallurgy burning process protection gas, etc.
Metallurgical industry: continuous casting, continuous rolling, steel annealing protective atmosphere, BOF top compound blowing nitrogen steelmaking, steelmaking BOF seal, BF top seal, BF ironmaking pulverized coal injection and other processes.
Using cryogenic liquid nitrogen
Electronic industry: large-scale integrated circuit, color TV picture tube, TV and recorder components and conductor production process protection, etc.
Food preservation: food, fruit (fruit), vegetables and other air conditioning storage and preservation, meat, cheese, mustard, tea and coffee, such as fresh packaging, jam, such as nitrogen oxygenation preservation, various bottles of wine purification and covering, etc.
Pharmaceutical industry: Chinese medicine (ginseng) nitrogen filling storage and preservation, western medicine injection nitrogen filling, storage tank and container nitrogen filling oxygen, drug pneumatic transmission of air source, etc.
Chemical industry: replacement, cleaning, sealing, leak detection and protection of gas, dry quenching, catalyst regeneration, petroleum fractionation, chemical fiber production, etc.
Fertilizer industry: raw material of nitrogen fertilizer. Catalyst protection copy, washing gas, etc.
Plastics industry: pneumatic transmission of plastic particles, plastic production and storage oxidation prevention.
Rubber industry: rubber packaging and storage, tire production, etc.
Glass industry: Protective gas for float glass production process.
Petroleum industry: nitrogen filling and purification of storage, containers, catalytic towers and pipelines, pressure leak detection of management systems, etc.
Offshore oil development: gas covering of offshore oil platforms, nitrogen injection for oil recovery, tank and container inerting, etc.
Lump storage: to prevent cellar, barn and other warehouse combustible dust ignition and explosion, etc.
Shipping: oil tanker cleaning gas, etc.
Aerospace technology: rocket fuel booster, launch pad replacement gas and safety protection gas, astronaut control gas, space simulation room, aircraft fuel pipeline cleaning gas, etc.
Other: paint and coating nitrogen oxygenation to prevent the polymerization of oil drying, oil and natural gas storage tanks and containers nitrogen oxygenation, etc.
Using cryogenic liquid nitrogen
Hypothermia medicine: surgical hypothermia, cryotherapy, blood refrigeration, drug freezing and cryopatter, etc.
Biomedicine: cryopreservation and transportation of precious plants, plant cells, genetic germplasm, etc.
Some industrial applications of nitrogen
In the process of industrial production, toxic and harmful, volatile, flammable and explosive materials need to be protected by inert gases. Nitrogen, as one of the inert gases, has a rich gas source, with a content of 79% in the air, and has been increasingly widely used in production. At present, the single making device is widely used in safety protection gas, replacement gas, nitrogen injection three times oil recovery, coal mine fire prevention and fire fighting, nitrogen based atmosphere heat treatment, anti-corrosion and explosion-proof, electronic industry, integrated circuit, etc.
Carbon molecular sieves and zeolite molecular sieves are used more in the field of nitrogen production. The separation of oxygen and nitrogen by molecular sieve is mainly based on the different diffusion rates of the two gases on the surface of molecular sieve. Carbon molecular sieve is a carbon-based adsorbent with some characteristics of activated carbon and molecular sieve. Carbon molecular sieves are composed of very small pores. The smaller diameter gas diffuses faster and enters the solid phase of the molecular sieve, so that the nitrogen enrichment component can be obtained in the gas phase. Molecular sieve nitrogen is air as raw material, with carbon molecular sieve as adsorbent, using the principle of pressure change adsorption, the use of carbon molecular sieve on oxygen and nitrogen selective adsorption and separation of nitrogen and oxygen method, commonly known as PSA nitrogen device.
As adsorbent for different gases in the adsorption capacity and adsorption speed, adsorption and other differences, as well as the adsorbent adsorption capacity varies with pressure change, therefore the PSA nitrogen making device can be finished in a pressurized conditions of mixed gas adsorption separation process, reduce pressure desorption adsorption by the impurity components, so as to realize the recycling of gas separation and adsorbent.
In some emerging material industry, electronic industry, integrated circuit, beer beverage and other inert gas applications are also constantly expanding new application fields. For example, the new PSA nitrogen production device has been used for inert protection of mobile phone lithium battery production, nitrogen packaging for beer and beverage, nitrogen dehydration and drying in organosilicone production, and nitrogen packaging for snack food instead of air and deoxidizer. The application of nitrogen makes the products of these enterprises in the process technology, product quality has been improved, to win the core competitiveness.
Gas separation equipment: localization is still the top priority
The new normal will be the main theme of the 13th Five-Year Plan period. From the perspective of the various fields of gas separation equipment application, after the 12th five-year development, petroleum, chemical, fertilizer, metallurgy, building materials, machinery and other fields, and photovoltaic industry, electronic industry, production capacity has reached the high level, further improve the possibility of smaller, this will make "much starker choices-and graver consequences-in" during the application of gas separation equipment in these areas is greatly reduced. But at the same time, China's GDP will maintain a growth rate of 6.5% ~ 7%, gas separation equipment industry will still have a certain development. In addition, market-oriented reform and the implementation of "going out" strategy are also expected to further stimulate the vitality of gas separation equipment.
At present, the gas separation equipment manufacturing industry has formed the following development ideas: in the "13th Five-Year" period, continue to promote the localization of super large air separation equipment, and realize the localization of supporting key components on the basis of fully mastering the complete set of integration technology. Products to high quality, better performance, technology integration direction development. Substantive progress has been made in the application research of special gases, high purity gases and rare gases. Promote the research of cryogenic engineering and petrochemical related products, especially natural gas and coalbed methane. Establish a large experimental research platform in the field of air separation and low temperature, and carry out research on the mechanism of air separation. It can be seen that localization is still the top priority in the development of gas separation equipment manufacturing industry in the "13th Five Year Plan".
Gas separation equipment industry should also accelerate the transformation from traditional manufacturing industry to manufacturing service industry. First, air separation equipment industry as the main body extends to both ends, the upstream focuses on the development of complete engineering service business, the downstream focuses on the development of industrial gas business, to strengthen the application research of industrial gas; Second, "expand the horizontal", while developing complete sets of air separation equipment and key supporting units business, take into account the horizontal development of petrochemical low-temperature related industries and characteristic products with competitive advantages; Third, while maintaining the domestic market share to open up the international market.