Working principle of cryogenic air separation equipment

Expander is a kind of equipment that uses the principle of mechanical work output when compressed gas expands and depressurizes to lower the temperature of gas. Expander is the key equipment to provide cooling capacity for air separation plant. The efficiency of expander directly affects the operation effect of air separation plant. The following introduces several factors that cause the efficiency reduction of expander.

Temperature difference is the power of heat transfer. As long as there is temperature difference between two materials, they will carry out the heat or cold transfer spontaneously. The heat is always transferred from the fluid with higher temperature to the lower temperature fluid. Although the heat transfer process of various heat exchangers is not identical, the heat transfer law is basically the same. The following is an example of the most widely used dividing wall heat exchanger: heat is transferred from hot fluid to cold fluid through the wall and flows in the opposite direction. The whole heat transfer process is divided into three stages. In the first stage, convection heat transfer: the heat flow body transmits heat to the wall surface. This process not only has heat transfer caused by the relative displacement of each part of the fluid, but also has heat conduction in the fluid, which is the comprehensive function of convection and heat conduction. In the second