Argon is a rare gas widely used in various industrial fields. It is used as a shielding gas for arc welding of metals such as stainless steel and aluminum, and as a purging gas in the smelting of metals such as steel, aluminum, titanium, and zirconium. It is also used in lighting technology and as a filling gas for fluorescent lamps. Industrial electronics also use argon as a shielding gas. Argon content in air is 0.932%. In air separation units, 30%-50% of the argon in the processed air can generally be obtained as a product. With the improvement of argon production technology and advanced air separation process flow and operation methods, the argon extraction rate has now been increased to over 80%.
Factors affecting the argon extraction rate in air separation equipment include: main column operating conditions, argon fraction control system, and crude argon column operating conditions. Stable main column operating conditions are a prerequisite for stable argon column operating conditions, while stable argon fraction operation is the foundation for stable crude argon column operation. All of these conditions are indispensable. The main factors affecting the main column's operating condition include the magnitude and frequency of load fluctuations in the air separation unit and changes in the amount of air entering the column caused by the switching process of the molecular sieve purifier. During daily operation, a specified variable load can be adopted to ensure the stability of the main column's operating condition. By improving the argon fraction control system, the control value can be appropriately reduced while ensuring argon fraction stability, thereby minimizing the fluctuation range of argon fraction. During operation, the exhaust valve at the top of the crude argon column can be opened 3%-5% periodically to increase the emission of crude argon gas while maintaining stable operating conditions, thus preventing nitrogen blockage in the crude argon column.
Through these methods, the nitrogen extraction rate of the air separation unit can be effectively improved, resulting in considerable economic benefits for the enterprise.