PSA nitrogen generator works based on pressure swing adsorption technology. It usually has two adsorption towers connected in parallel and filled with adsorbents such as carbon molecular sieve. The air enters the adsorption tower after being compressed by the compressor. Under high pressure, the carbon molecular sieve selectively adsorbs impurity gases such as oxygen, carbon dioxide, and water vapor to allow nitrogen to pass through and achieve preliminary separation of nitrogen and oxygen. While one adsorption tower is adsorbing, the other is desorbing. Desorption reduces the pressure to desorb and discharge the adsorbed impurity gas from the pores of the carbon molecular sieve to regenerate the adsorbent. The two adsorption towers are alternately pressurized for adsorption and decompressed for regeneration. The control system accurately controls the adsorption and desorption time and valve switching. The cycle operation is like this to continuously produce high-purity nitrogen.
Application in food packaging
Prevent food from oxidation and deterioration: Many foods, such as potato chips and nuts, are rich in oil. During the packaging process, oxygen will cause the oil in the food to oxidize, produce a rancid smell, and affect the taste and quality of the food. The nitrogen generated by the PSA nitrogen generator can fill the food packaging bag, discharge the oxygen, and effectively extend the shelf life of the food. For example, in the packaging of fried potato chips, the injection of nitrogen allows the potato chips to maintain their crisp taste during storage, because the oxygen-free environment formed by nitrogen inhibits the oxidation of oil.
Maintain the appearance and color of food: For some colored foods, such as bacon, dried fruits and vegetables, oxygen will change their color. Take bacon as an example. In an aerobic environment, the color of bacon will gradually dim and even change color. Using nitrogen packaging can maintain the original ruddy color of bacon, making it more attractive. This is because nitrogen prevents oxygen from oxidizing with pigments and other ingredients in food.
Application in food processing
Protective gas for processing equipment: In food processing equipment, some high-precision processing links, such as food slicing and grinding, need to prevent metal parts from rusting. Nitrogen can be used as a protective gas to prevent metal parts in processing equipment from contacting with oxygen and moisture in the air. For example, in a meat slicer, nitrogen can prevent the blade from rusting, thereby ensuring the quality of the slices and extending the service life of the equipment.
Application in food drying process: In food drying processes, such as the production of raisins and dried mushrooms, nitrogen can be used as a drying medium. Compared with air, nitrogen as a drying medium can reduce oxidation reactions in food. For example, in the drying process of raisins, the use of nitrogen drying can better maintain the nutrients and color of raisins because nitrogen prevents the sugar and other nutrients in raisins from being oxidized.
Application in food storage links
Protective gas for large food storage facilities: In large food warehouses or storage tanks, nitrogen can be used to create an oxygen-free environment. The use of nitrogen is particularly important for foods such as grains and milk powder that are susceptible to pests and oxidation. For example, during the storage of milk powder, nitrogen can prevent the fat and protein in the milk powder from being oxidized, and it can also inhibit the growth of pests, because many pests cannot survive in an oxygen-free environment.
Application in wine storage: During the storage of wine, nitrogen can be used to fill the top space of oak barrels or wine bottles. The ingredients in wine, such as alcohol and phenolic substances, easily react with oxygen, causing the wine to deteriorate. Nitrogen filling can effectively prevent the oxidation of wine and maintain its flavor and quality. For example, some high-end wines are injected with nitrogen after bottling to extend the wine's drinking period.