The lower tower and upper tower in the air separation equipment are the main equipment in the distillation system of the cryogenic oxygen air separation equipment. They work together to complete the task of air separation.
The main function of the lower tower is to perform preliminary separation of air. During the distillation process, the liquid flows through the sieve plate one by one from top to bottom. Due to the effect of the overflow weir, a certain liquid level height will be formed on the tray. When gas passes through the small holes of the sieve plate from bottom to top, it comes into contact with the liquid and generates bubbles, thereby increasing the gas-liquid contact area and enabling effective heat and mass exchange processes. Low boiling point components (such as nitrogen) gradually evaporate into the gas phase, while high boiling point components (such as oxygen) gradually liquefy into the liquid phase. In this way, low boiling point pure nitrogen can be obtained at the top of the lower tower, while high boiling point oxygen rich liquid air components can be obtained at the bottom of the tower.
The main function of the upper tower is to further distill and separate the oxygen rich liquid air sent from the lower tower. During the distillation process in the upper tower, the gas rises along the packed tray through the distributor, while the liquid is evenly distributed on the packing tray from top to bottom through the water separator. The gas and liquid on the surface of the packing are in complete contact for effective heat exchange. The low boiling point oxygen content in the rising gas continues to increase, and a large amount of high boiling point component oxygen is washed down to form reflux liquid. Finally, low boiling point pure nitrogen gas is obtained at the top of the tower, and high boiling point liquid oxygen is obtained at the bottom of the tower.
