Detailed introduction
　　Alcohol distillation column contains not only alcohol but also dozens of other substances in fermented mash. If water is added, the content of these substances far exceeds the content of alcohol. The content of alcohol in mature mash is only about 7-11%. The impurities including water, alcohols, aldehydes, acids and lipids account for almost 90%. In order to obtain pure alcohol, a certain amount of alcohol must be used. Method: Alcohol was separated from mature mash. In production, various boiling points, specific gravity and volatile substances are separated from different equipment by means of heating distillation, so that higher purity alcohol can be obtained. The working principle of the crude distillation tower is that the fermented mash is preheated and then enters the upper part of the crude distillation tower. The bottom of the tower is continuously uniformly fed with heating steam. At this time, the liquid alcohol in the mature mash can be converted into alcohol gas due to heating. At the same time, other impurities with low boiling point and volatility become gaseous, and enter the aldehyde discharging tower together with alcohol (or directly into the distillation tower). At the bottom, the distilled waste residue is discharged out of the tower. When the crude distillation column is in normal operation, the top temperature of the tower should not be lower than 93 C, but it should not be too high. Excessive top temperature is not conducive to separation, and the consumption of steam is large. Generally controlled at 95 - 96 C. When the temperature is too low, the alcohol in waking does not evaporate completely, and the rate of escaping alcohol increases obviously. The boiling point of pure alcohol is 78.3 C, but the boiling point of mixed liquids mixed with water and other components is far more than 78.3 C. Therefore, the bottom temperature of crude distillation column should not be lower than 105 C, generally between 105 C and 109 C. The mature mash must be preheated before entering the crude distillation column to reduce the temperature difference, which is conducive to the stable operation of the crude distillation column. Generally, the preheating temperature of mash should be controlled between 60 - 70 C. Because of the influence of equipment performance, some production units generally have a low temperature of 5 - 10 C. The working principle of the dealdehyde tower is that the alcohol in the mature mash is roughly distilled, and then the gas enters the dealdehyde tower from the top of the crude distillation tower. The low boiling point and volatile impurities such as aldehydes and esters in the crude alcohol are discharged from the dealdehyde tube by heating, condensation and reflux in the dehyde tower. The dealdehyde alcohol enters the liquid distillation tower from the bottom of the aldehyde tower and part of the wine head enters the liquor head tube after entering. In fermenter mash or mature mash. Normally, the bottom temperature of the aldehyde removal tower is 86-89 C, the top temperature of the tower is 79 C, the water temperature of the 1* condenser on the aldehyde removal tower should not be lower than 60 C, and the temperature of the last condenser should not be lower than 25 C. The working principle of the distillation column is that after the distillation of alcohol through the above two towers, the concentration of alcohol still needs to be further improved and the impurities need to be further eliminated. The distillation purpose of the distillation column is to obtain the finished product of alcohol which meets the quality standard by heating evaporation, condensation and reflux, removing the first impurities, extracting fusel oil and discharging the tail impurities. The top temperature of distillation column should generally be controlled at 79 C, the bottom temperature should be controlled at 105 - 107 C, and the temperature of distillation column should be between 88 - 92 C under the normal condition of liquor extraction. The water temperature of 1 * condenser on distillation column should be 60 - 65 C, 2 * condenser should be 35 - 40 C, and the last condenser should be at least 25 C.