Air separation technology (AST) is the process of physically separating the main components of air-oxygen, nitrogen, and other rare gases-through physical methods. With the development of industry, particularly in the steel, chemical, and electronics sectors, the demand for high-purity oxygen and nitrogen continues to increase, driving the development of ASU technology and its associated equipment. This article will explain the main types of ASUs and analyze their development history.
Classification of air separation units
1. Low temperature distillation method
Cryogenic distillation is one of the most widely used air separation technologies currently. It works by cooling the air to very low temperatures, liquefying it and then separating the different components based on their different boiling points. This method can produce high-purity oxygen and nitrogen and is widely used in metallurgy, chemical and other industries.
Data shows that in 2025, about 70% of global oxygen production will rely on cryogenic distillation. Due to its high efficiency and stability, this ratio is expected to remain stable in the coming years.
2. Pressure swing adsorption (PSA)
Pressure swing adsorption is a separation technology based on the difference in adsorption capacity of different gases on solid surfaces. This technology has the characteristics of simple operation and low energy consumption, and is especially suitable for small and medium-scale oxygen or nitrogen production.
According to the latest research, as of 2025, the proportion of equipment using pressure swing adsorption to produce oxygen in the world will reach about 20%, especially in the medical field.
3. Membrane separation method
Membrane separation uses membranes made of specific materials to selectively separate components in the air. Although its purity is not as good as the first two methods, it shows unique advantages in fields such as emergency oxygen supply because of its portability and flexibility.
By 2025, membrane separation technology will account for approximately 5% of the global air separation market, showing a steady growth trend.
Development history
1. Early exploration stage (early to mid-20th century)
At this stage, scientists began experimenting with cryogenic techniques to separate components in the air. In 1902, German chemist Carl von Linde successfully developed the first machine for air liquefaction, marking the beginning of modern air separation technology. By the mid-20th century, with the advancement of refrigeration technology and materials science, cryogenic distillation gradually became mainstream.
2. Technology maturity period (mid-to-late 20th century to early 21st century)
As the demand for oxygen increased, especially in the metallurgical and chemical industries, cryogenic distillation methods were further improved and developed. At the same time, the pressure swing adsorption method also received attention during this period and began to be commercially applied. After entering the 21st century, with the enhancement of environmental protection awareness and technological advancement, more environmentally friendly and efficient separation technologies such as membrane separation have also been developed.
3. Modern innovation and development (21st century to present)
Since entering the 21st century, with the development of new energy, new materials and information technology, air separation technology has ushered in new development opportunities. For example, the introduction of intelligent control systems makes the operation of air separation units more precise and efficient; the application of new materials improves separation efficiency and reduces energy consumption. In addition, with the global focus on sustainable development, how to reduce energy consumption and environmental impact during the air separation process has become a research hotspot.
The development history of air separation plants reflects the technological progress of human society. From the initial cryogenic distillation method to the current situation where multiple technologies coexist, every technological innovation has greatly promoted the development of related industries. In the future, with the continuous innovation of technology and changes in social needs, Shenger gas air separation technology will continue to develop in a more efficient and environmentally friendly direction. It is expected that the global air separation market will reach a new height by 2030, with the application of new technologies becoming a key factor driving this growth.
