Liquid oxygen is an important industrial gas. How to manufacture liquid oxygen

Liquid Oxygen (LOX) is an important industrial gas widely used in medical, chemical, aerospace and other fields. The preparation of liquid oxygen is mainly achieved through air separation technology, and the specific process is as follows:
1. Compressed air
Firstly, the air in the atmosphere is sucked into the compressor for compression. This step can increase the partial pressure of each component in the air, preparing for the subsequent separation process.
2. Preprocessing
Compressed air needs to be pre treated to remove impurities such as moisture and carbon dioxide. These impurities will freeze under low temperature conditions, affecting the subsequent separation efficiency. Usually, adsorbents such as molecular sieves are used to complete this process.
3. Cooling
Next, the purified air will be cooled to an extremely low temperature. This step is usually achieved using a heat exchanger and an expander (or throttle valve). During the expansion process, air will do external work, causing its own temperature to decrease and reach the desired low temperature state.
4. Separation
When air is cooled to near its boiling point (approximately -196 ° C), different gas components begin to gradually liquefy due to their different boiling points. The boiling point of nitrogen is lower than that of oxygen, so it liquefies before oxygen. By repeatedly evaporating and condensing liquid air through a distillation tower, oxygen can be effectively separated from other components (mainly nitrogen). During this process, heavier oxygen tends to stay at the bottom, while lighter nitrogen rises to the top.
5. Collection and storage
The separated liquid oxygen is then collected and stored in specially designed low-temperature storage tanks to maintain its liquid form. These storage tanks typically have good insulation properties to reduce heat transfer and prevent liquid oxygen evaporation.
6. Quality inspection
Finally, in order to ensure product quality, the produced liquid oxygen also needs to undergo strict quality testing, including testing of purity, moisture content, and other indicators.
The entire production process needs to be operated by experienced technicians in a professional factory and strict safety regulations must be followed, as liquid oxygen is highly flammable and improper handling may cause fires or explosions.