The core of the working principle of the cold box of the air separation equipment is to use the enclosed low-temperature environment to realize the deep air separation through the coordination of the integrated system, specifically as follows:
1. The cold box is a sealed structure to build a low-temperature environment, and the key systems such as heat exchange, rectification, refrigeration and liquid treatment are integrated inside to provide basic conditions for the separation operation;
2. The plate-fin heat exchanger plays a core heat exchange role to realize the deep air cooling and efficient cold recovery, reduce energy consumption and lay a low temperature foundation for subsequent separation;
3. Relying on the difference of boiling points of oxygen and nitrogen, the high and low pressure rectification tower completes the high-precision separation of air through the countercurrent contact of vapor and liquid to ensure the purity of oxygen and nitrogen;
4. The expander provides the key low-temperature cooling capacity for the system and maintains the stable cryogenic working condition of the unit;
5. The supporting low-temperature pipeline, valve and liquid storage and transportation system form a closed and efficient separation unit to avoid cold loss and external interference and ensure the stable operation of the overall process.
