Alcohol

Corn purification is performed to remove impurities such as iron, sand, stones, and stems from corn, thereby improving the quality of raw materials and protecting production equipment. The raw materials are cleaned using equipment such as rotary screens, magnetic separators, and aspirators.

To increase the heating surface area of starch granules and facilitate their water absorption, swelling, and gelatinization, the heat treatment efficiency is improved and heat treatment time is shortened. Corn is transported by a belt conveyor to the crushing workshop. After being crushed by a hammer mill, conveyed by negative pressure air, and unloaded by a cyclone, the corn flour is sent to a slurry tank via a screw conveyor.

Corn starch dissolves in water after swelling and cooking for hydrolysis under the action of liquefying enzymes to produce a series of dextrins, completing the liquefaction process. It is further hydrolyzed by saccharifying enzymes to obtain fermentable sugars.

The alcohol fermentation process involves yeast converting fermentable sugars into alcohol and CO₂ through biochemical reactions mediated by intracellular zymase enzymes, and expelling these products through the cell membrane. In continuous fermentation, the saccharified mash is added continuously, with simultaneous saccharification and fermentation. Yeast converts fermentable sugars into alcohol, which enters the distillation process with the mature mash. CO₂ is discharged into the atmosphere through a scrubber (or used for producing CO₂ products), while the fermentation heat generated is dissipated through forced external circulation via a plate type heat exchanger to ensure normal yeast metabolism.

The volatility of various substances contained in the mature mash differs. The mash is vaporized and condensed repeatedly in the column, concentrating ethanol in the mixture. The preheated mature mash is transported into a crude distillation column, where it is separated into crude alcohol vapor and spent mash. The condensed crude alcohol vapor is injected to a crude alcohol tank and is further concentrated and purified in a rectification column via pumping to obtain alcohol with a concentration above 95%.

Alcohol concentration is achieved through a molecular sieve adsorption bed to obtain alcohol with a concentration above 99.5% (V/V). When wet alcohol vapor passes through the adsorption bed, water is adsorbed, and alcohol is concentrated and flows through the sieve bed. By virtue of the temperature and pressure swing adsorption technology, the adsorption and desorption processes are alternated, enabling continuous feed and discharging operations.