When the air volume increases, the purity of oxygen and nitrogen will be affected.
The amount of oxygen extracted will affect the amount of steam in the upper tower. If the extraction amount of oxygen is large, it will increase the reflux ratio of the upper tower, causing the nitrogen in the liquid phase to not be completely evaporated, thereby affecting the purity of oxygen. When the amount of expanding air entering the upper tower increases, it will disrupt the normal distillation conditions of the upper tower, resulting in a decrease in oxygen purity. When maintaining a fixed level of air volume and nitrogen concentration during processing, if high purity requirements are placed on oxygen, the amount of oxygen extracted can only be within a certain range. If a large amount of oxygen is required, the purity of oxygen will inevitably be affected and the purity will decrease.
When the air volume increases, the reflux ratio of the lower tower may decrease (under constant air separation load), which can lead to an increase in liquid air purity and a decrease in nitrogen purity in the lower tower. But if only increasing the air volume in the lower tower without making other adjustments, it may also disrupt the normal distillation conditions due to phenomena such as flooding, thereby affecting nitrogen purity. Due to the increase in the amount of expanding air entering the upper tower, the purity of nitrogen discharge will decrease. This will also affect the purity of the nitrogen gas ultimately separated from the upper tower.
In order to ensure the purity and yield of oxygen and nitrogen meet production needs, flexible adjustments need to be made based on the actual operating status and adjustment measures of the air separation equipment.
