The technology of using the different boiling points and relative volatility of components to achieve the separation of different substances has had a preliminary development in the handicraft era, which is the so-called distillation condensation separation technology. In fact, the so-called distillation technology is the special case that there is no distillation section in the rectification technology, only the distillation section and the theoretical number of plates is 1, and condensation is no distillation section in the rectification technology. Only the distillation section and the number of theoretical plates is 1. The most important application case is to make high-alcohol liquor from low-alcohol fermented wine, and heat low-concentration fermented wine with fire or steam. Both water and alcohol in fermented wine will evaporate into the gas phase, but alcohol will evaporate into the gas phase more than water due to its low boiling point and higher volatility. Then use cooling water or natural air to cool the mixed steam of alcohol and water will be higher than the liquor alcohol concentration, of course, with the progress of distillation, the alcohol concentration of fermented wine decreases, and the alcohol concentration of distilled wine condensed by the gas phase also decreases accordingly, so the distilled wine has the first way of wine, two ways of wine. Whether it is the first or two Xiao Xiao wine is a mixture of water and alcohol, but the alcohol concentration is different, in order to get a higher concentration of liquor or even pure alcohol, it is necessary to repeat distillation and condensation. When the cryogeny-air separation textbook talks about how to produce oxygen, it also makes a similar deduction, that is, the use of liquid-air repeated distillation to obtain pure oxygen, but this process is actually impossible to happen, because the air separation distillation is a distillation process with a boiling point below the ambient temperature, and the cryogeny-air separation textbook describes only a thought experiment.
