Model of air separation unit

Distillation is using the different boiling points of the two substances to condense the mixed steam and vaporize the mixed liquid repeatedly to achieve gas separation. For a mixed liquid composed of two substances with different boiling points, when the heat absorption part evaporates, the volatile components will evaporate more, while the mixed steam will give off heat and partially condense, the non volatile components will condense more. If the saturated steam with higher temperature is mixed with the saturated liquid with lower temperature, the steam will release heat and partially condense, and the liquid will absorb heat part of it evaporates. If after a round of partial evaporation and partial condensation, the steam and liquid with higher concentration will contact with the steam and liquid with different temperature respectively, and then partial condensation and partial evaporation will occur again. This process will be repeated for many times, and finally gas separation

At present, there are two types of common condensing evaporators in domestic air separation units, plate fin condensing evaporator and tubular condensing evaporator. Tubular condensing evaporator is divided into three types: long tube, short tube and coil. The long tube and short tube are all in row. The tube is made of red copper and the tube sheet is made of brass. It is generally used in small and medium-sized air separation plants. Coil type is generally used for auxiliary condensing evaporator. Because there is no fixed liquid level in the coil, the heat transfer coefficient is small, so it has been gradually eliminated. The plate fin condenser evaporator is made of all aluminum structure, and the plate unit is arranged in vertical star shape. Its characteristics are compact structure, light weight, small volume and easy to manufacture. It is widely used in large and medium air separation plants. Due to the gradual enlargement of the air separation unit, the heat excha