Recycle old air separation plant

In the switching heat exchanger, moisture and carbon dioxide cannot be completely and thoroughly removed. Although the remaining amount is very small, it will gradually block the switching heat exchanger over time. In the production, it shows that the resistance of switching heat exchanger increases continuously, the free section of gas flow decreases, and the air volume cannot enter. In addition, in the cold section of the switching heat exchanger, carbon dioxide has been basically cleaned up theoretically, but due to the clamping effect of air flow, the amount of carbon dioxide brought into the tower is much more than the theoretical content. Apart from being partially cleared by the adsorption filter, the rest of the carbon dioxide will gradually accumulate in the tower and block the tower plates, pipelines and valves. In addition, the air also contains a small amount of acetylene and hydrocarbon. Although adsorbed by acetylene adsorber, its adsorption efficiency can only reach a...

The liquid nitrogen supercooler uses the low temperature gas nitrogen from the upper tower to cool the liquid nitrogen from the lower tower, so as to reduce the gas rate when the liquid nitrogen throttling enters the upper tower. Why is the temperature of gas nitrogen lower than that of liquid nitrogen? This is because for the same substance, phase change temperature (saturation temperature) is related to pressure. The lower the pressure is, the lower the corresponding saturation temperature is (see Figure 8 ). On the top of the tower, it is in the saturated state of the coexistence of gas nitrogen and liquid nitrogen, both of which have the same saturation temperature. The absolute pressure of nitrogen going out of the tower is about 0.13MPa, and the corresponding saturation temperature is-193℃, which is also the temperature of the nitrogen saturated vapour going out of the tower. The absolute pressure on the top of the lower tower is about 0.55MPa, and the corresponding nitrogen s...