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Product features of PSA nitrogen generator

With the rapid development of industry, nitrogen has been widely used in the fields of chemicals, electronics, metallurgy, food, machinery, etc. The demand for nitrogen in my country is increasing at a rate of more than 8% every year. Nitrogen is chemically inactive, and it is very inert under ordinary conditions, and it is not easy to chemically react with other substances. Therefore, nitrogen is widely used as shielding gas and sealing gas in the metallurgical industry, electronics industry, and chemical industry. Generally, the purity of the shielding gas is 99.99%, and some require high purity nitrogen of more than 99.998%. Liquid nitrogen is a more convenient cold source, and it is more and more commonly used in the food industry, medical industry, and the semen storage of animal husbandry. In the production of synthetic ammonia in the chemical fertilizer industry, if the raw material gas of synthetic ammonia—hydrogen and nitrogen mixed gas is washed and refined with pure liquid nitrogen, the content of inert gas can be extremely small, and the content of sulfur monoxide and oxygen does not exceed 20 ppm.

Pure nitrogen cannot be drawn directly from nature, and air separation is mainly used. Air separation methods include: cryogenic method, pressure swing adsorption method (PSA), membrane separation method.

Introduction to the process and equipment of PSA nitrogen generator

Introduction to the process flow

The air enters the air compressor after removing dust and mechanical impurities through the air filter, and is compressed to the required pressure. After strict degreasing, dewatering, and dust removal purification treatments, clean compressed air is output to ensure the use of molecular sieves in the adsorption tower. life.

There are two adsorption towers equipped with carbon molecular sieve. When one tower is working, the other tower is decompressed for desorption. The clean air enters the working adsorption tower, and when it passes through the molecular sieve, oxygen, carbon dioxide and water are adsorbed by it. The gas flowing to the outlet end is nitrogen and trace amounts of argon and oxygen.

Another tower (desorption tower) separates the adsorbed oxygen, carbon dioxide and water from the pores of the molecular sieve and discharges it into the atmosphere. In this way, the two towers are carried out in turn to complete the nitrogen and oxygen separation and continuously output nitrogen. The purity of nitrogen produced by pressure swing (_bian4 ya1) adsorption is 95%-99.9%. If higher purity nitrogen is required, nitrogen purification equipment should be added.

The 95%-99.9% nitrogen output from the pressure swing adsorption nitrogen generator enters the nitrogen purification equipment, and at the same time an appropriate amount of hydrogen is added through a flowmeter, and the hydrogen and trace oxygen in the nitrogen are catalytically reacted in the deoxygenation tower of the purification equipment to remove The oxygen is then cooled by a water condenser, the steam-water separator is dewatered, and then deep-dried by a dryer (two adsorption drying towers are used alternately: one is used for adsorption and drying to remove water, the other is heated for desorption and drainage to obtain high-purity nitrogen. The purity of nitrogen can reach 99.9995%. At present, the largest production capacity of pressure swing adsorption nitrogen in the world is 3000m3n/h.