PSA full name: Pressure Swing Adsorption， The Chinese meaning is: pressure swing adsorption. PSA is a new gas separation technology that utilizes the difference in adsorption performance of molecular sieves for different gas molecules to separate gas mixtures. It uses air as the raw material and utilizes the selective adsorption performance of a high-performance and highly selective solid adsorbent for nitrogen and oxygen to separate nitrogen and oxygen from the air. With the rapid development of industry, nitrogen has been widely used in fields such as chemical engineering, electronics, metallurgy, food, and machinery. China's demand for nitrogen is increasing at a rate of over 8% per year. The chemical properties of nitrogen are not active, and it exhibits great inertness in its normal state, making it difficult to undergo chemical reactions with other substances. Therefore, nitrogen is widely used as a protective gas and sealing gas in the metallurgical industry, electronics industry, and chemical industry. The purity requirement for protective gas is generally 99%, with a higher requirement of 99.9%. The highest requirement is 99.9995%. Oxygen content below 5ppm is used as a protective gas.