Talk about the distillation and rectification of alcohol

Alcohol distillation dates back thousands of years. In ancient times, people would eat wild fruits that had been on the ground for a long time to satisfy their hunger. They discovered that wild fruits that had been on the ground for a long time would have a different, fragrant and sweet taste. They were inspired by this and learned how to make wine. However, directly brewed wine is not easy to store and will completely change its flavor over time.

Later, humans extended the storage time by heating, but heating would affect the taste. By chance, someone discovered that during the heating process of wine, the condensed liquid on the pot lid had the same strong and sweet taste.

So humans learned to use steaming to collect steam and then cool it with water to obtain a clear and transparent condensate, which is wine, which can be preserved for a long time while maintaining its original flavor. Since then, alcohol distillation has been applied and continuously developed.

The principle of distillation is actually very simple. In a nutshell: substances are separated through the different boiling points of various substances. Alcohol, whose scientific name is ethanol, is easy to volatilize, with a boiling point of 78°C. During the heating process, it is easy to vaporize and run out of the mash liquid and separate from the mash residue.

In the distillation process, substances with low boiling points are evaporated first, and substances with high boiling points are evaporated last. A heating vessel is used to cook the wine and condense the wine vapor. This process is called simple distillation. The wine obtained after only one simple distillation is still turbid and white, with a strong and spicy taste. There are "turbid wine" and "baijiu" called. Later, humans used the method of re-distilling multiple times to make the wine clearer and clearer, and the alcohol content continued to increase, producing "strong wine".

In the industrial age, science and technology developed rapidly, and people discovered that although multiple simple distillations could achieve the desired goals, the steps were extremely cumbersome and the manufacturing costs were high. At this time, the theory of distillation appears. Distillation is a distillation method that uses reflux to separate liquid mixtures with high purity.

The theory of distillation is relatively complex and can be simply understood as the superposition of multiple simple distillations to form distillation. A simple distillation is to hold a mixture in a heater, heat it at the bottom, and then discharge low-boiling substances from the top in large quantities in the form of gas.

Distillation is to stack multiple simple distillations together from bottom to top. The important tool in simple distillation - "pot", is stacked one on top to become the most important tool in distillation. Important tool - "Distillation Tower".

The working principle of the distillation tower can also be easily understood in this way. The bottom pot (temporarily called pot No. 1, which is actually the first tray in the distillation tower) is heated directly or indirectly by steam, and low-boiling-point substances and some high-boiling-point substances escape from pot No. 1 in the form of gas. The gas is then condensed by the liquid in the pot above (pot 2). The gaseous high-boiling-point substances evaporated from the No. 1 pot will be condensed preferentially, and heat will be generated after condensation (similar to water vapor that will release a lot of heat after condensation). This heat will preferentially vaporize the low-boiling-point substances in the No. 2 pot. , so that more low-boiling-point substances and a small amount of high-boiling-point substances in pot No. 2 diffuse to pot No. 3.

After circulating through multiple pots in this way, we can get a very high concentration of low boiling point substances from the top pot, and a very high concentration of high boiling point substances from the bottom pot.

Distillation is widely used in petrochemical, light food, metallurgy and other industries. The tall, thin ironware installed everywhere in chemical plants is the distillation tower. Whether it is alcohol or ethyl ester, the final concentration is completed by the distillation tower to obtain qualified products.