Sichuan air separation plant

The temperature condition adjustment of the cooler (or switching heat exchanger) is based on the central temperature. The "middle" mentioned here does not refer to the central position of geometric dimension, but refers to the temperature on the barrel (or switching channel) near the central air extraction or the outlet of circulation. It is also related to the location where the thermometer is installed. The purpose of temperature condition adjustment is to keep the temperature difference between cold end and hot end within the specified range. Then, why should the temperature in the middle prevail? We need to take a look at the relationship between the temperature of the middle part and the temperature difference of the cold end and the temperature difference of the hot end, and what rules the temperature changes along the height direction of the cooler (or the switching heat exchanger) follow. The temperature condition change of the cooler (or switching heat exchanger) is general...

The reflux liquid in the upper column of the distillation column is throttled by the lower column to the liquid air and liquid nitrogen of the upper column, and the reflux ratio of the upper column is regulated by the liquid nitrogen throttle valve. When the liquid air and liquid nitrogen pass through the throttle valve, the pressure will decrease, and the corresponding saturation temperature will also be reduced. If the supercooling degree of liquid is not enough, some liquid will be vaporized. The higher the gasification rate is, the lower the reflux ratio of the upper column is, and the purity of nitrogen is affected. Therefore, in order to improve the supercooling degree of the liquid nitrogen in the night sky through the throttle valve, a subcooler is generally set up to increase the supercooling degree of the liquid nitrogen in the liquid air.