Air is the "life gas" that we breathe every day, and its main components are nitrogen and oxygen. According to the volume fraction, nitrogen is about 78%, oxygen is about 21%, and the other 1% includes rare gases such as helium, neon, argon, krypton, xenon, radon, etc. The volume fraction is about 0.934%, about 0.034% of carbon dioxide, and about 0.002% of water vapor, impurities, and other substances.
Although these gases are transparent, colorless, and odorless, and cannot be easily detected by people, they have an important impact on the survival and production of human beings. People's industrial production: iron and steel making, ammonia synthesis process, rocket fuel, etc. all need a lot of oxygen but are directly extracted from the air in the production of the required oxygen; green plants also need oxygen for respiration. It can be seen that oxygen is necessary for all oxygen-demanding organisms.
Nitrogen in the atmosphere, although more than oxygen, it is an inert gas, its nature is not active, often used as a protective gas, such as in melons, fruits, food, and light bulbs filling gas. To prevent certain objects from being oxidized by oxygen when exposed to air, fill the granary with nitrogen, so that the grain does not mold, not germinate, for long-term preservation.
With the rapid development of industry, nitrogen has been widely used in chemicals, electronics, metallurgy, food, machinery, and other fields, and the demand for nitrogen in China is increasing at a rate of more than 8 percent per year. The chemical property of nitrogen is not active, and it shows great inertness in an unusual state, and it is not easy to have a chemical reaction with other substances. Therefore, nitrogen is widely used as a protective gas and sealing gas in the metallurgical industry, electronic industry, and chemical industry, and the general purity of protective gas is 99.99%, and some require 99.998% or more high purity nitrogen. However, pure nitrogen cannot be drawn directly from nature, so in order to better improve the utilization rate of nitrogen in industrial production, companies mainly use the air separation method. Air separation methods include deep cooling, pressure swing adsorption (PSA), and membrane separation. The following is a brief introduction to the application of oxygen analyzers in PSA-type nitrogen generators.
Working Principle PSA Type Nitrogen Generator
PSA (Pressure Swing Adsorption) is a new gas separation technology that uses the difference in "adsorption" properties of molecular sieves for different gas molecules to separate gas mixtures, which is based on air as raw material and carbon molecular sieves as adsorbent. Using the principle of variable pressure adsorption, the nitrogen and oxygen are separated by the selective adsorption of carbon molecular sieves on oxygen and nitrogen, commonly known as PSA nitrogen production. Technology has been rapidly developed in foreign countries since the late 60s and early 70s.
Features of PSA nitrogen generator
- low cost: PSA process is a simple method of nitrogen production, nitrogen is produced in a few minutes after the machine is turned on, energy consumption is low, and the cost of nitrogen is much lower than the deep cooling method of air separation nitrogen production and liquid nitrogen on the market.
- reliable performance: imported microcomputer control, fully automatic operation, no need for special training of operators, just press the start switch, it can automatically run, to achieve continuous gas supply.
- High purity of nitrogen: the instrument detects trace oxygen and traces water to ensure the purity of nitrogen required, and the purity can reach 9999%.
- the use of imported molecular sieve: with a large adsorption capacity, strong anti-pressure performance, long service life, and other characteristics.
- High-quality control valve: Imported special pneumatic valve can ensure the reliable operation of nitrogen equipment.
Working principle of nitrogen generator
The workflow of the nitrogen generator is controlled by the programmable controller which controls the three pilot solenoid valves, and then the solenoid valves control the opening and closing of the eight pneumatic pipeline valves respectively to complete. The three pilot solenoid valves control the left suction, equal pressure, and right discharge respectively. When the process is in the left suction state, the solenoid valve controlling the left suction is energized and the pilot gas is connected to the left suction inlet valve, the left suction production valve, and the right exhaust valve, making these three valves open to complete the left suction process and the right adsorption tank desorption at the same time. When the process is in the equal pressure state, the solenoid valve controlling the equal pressure is energized and the other valves are closed; the pilot gas is connected to the upper and lower equal pressure valves, which makes these two valves open and complete the equal pressure process. From the principle of PSA type nitrogen generator above, we know that in the adsorption tank of variable pressure adsorption nitrogen generator, when the pressure is high, the carbon molecular sieve adsorbs the oxygen in the air, and the nitrogen that is not easily adsorbed becomes the product; when the pressure is low, the oxygen is desorbed from the carbon molecular sieve. Using the change of pressure, the required nitrogen can be effectively separated from the air.