Questions about the taste of alcohol!
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In 2005, our company introduced a set of premium alcohol production equipment from the United States with an annual output of 150,000 tons of alcohol! This equipment was put into production in April 2007. In more than two years of operation, the equipment has been operating at full capacity, and all physical and chemical indicators of the finished wine can reach Premium grade standards (such as fusel oil, n-propanol, methanol, acetaldehyde); however, during high-load operation, the taste of the finished alcohol produced by the distillation unit is not good and can only meet the standard of ordinary grade alcohol, but the laboratory cannot detect which impurities are present. According to my personal opinion, it may be related to the temperature of the tower. When running at 100% load, the steam consumption of the polishing tower increases, and the temperature can reach 152-153 degrees. At this temperature, the following high boiling point impurities, such as furfural, may be produced, which may affect the taste of alcohol. (At 70% load, the taste basically meets the requirements of the premium grade. At this time, the temperature of the polishing tower is about 145 degrees.) Please help discuss what may cause the taste problem.
Low oxidation time is the main reason, and unsaturated aldehydes also affect the taste! The most important thing is that if the alcohol contains trace amounts of sulfides, it will have a huge impact on the taste! You may consider adding a copper device to the reflux of the distillation tower! It can improve the taste! The key at present is to increase the amount of aldehyde discharge, especially to increase the temperature of the final cooler! More mention of denatured alcohol! Control the extraction rate of industrial alcohol at 5%!
2# henan2006 Now the aldehyde content in the finished product is below 1mg/L, which is already very low! I know that copper can remove odors, and our distillation tower also has 5 layers of copper trays at the extraction outlet! The industrial wine extraction rate now accounts for about 20% of the total alcohol, which is already very high!
What is the oxidation time? Are the production raw materials moldy? Pay attention to the gas impurities in the crude tower and water washing tower! Is there a pipeline to add steam condensate to the washing tower if necessary? Reduce the waste water at the bottom of the distillation tower. It may be that impurities are circulating in the system! Have you added alkali? If so, stop and give it a try. Adding too much alkali will definitely affect the taste! Reflux the methanol tower to see if the color changes. If the color changes, it means impurities have accumulated in the methanol tower. Increase the temperature of the methanol tower condenser and discharge the impurities in the form of gas! The proportion of industrial alcohol extracted is too high! no need!
4# henan2006 The oxidation time is about 60 minutes, basically not less than 40 minutes. The mash at the bottom of the crude tower goes directly to the feed system. Adding fresh water to the washing water in the water washing tower can indeed improve the taste, but the conditions are still met; in the methanol tower, we have a flow of industrial wine (liquid phase) from the reflux tank. As for the color, we haven’t paid much attention yet! The key issue is that the taste changes significantly when running at low load! One thing worth noting is that at low load, the reflux ratio of the purification tower is much higher than when running at high load. The extraction outlet of fusel oil and n-propanol should be at the desired extraction position at low load. I suspect it has something to do with the reflux. But at present, due to problems with the design of the reboiler, it is impossible to continue to increase the reflux at high load! In the future, at low load, I will try to reduce the reflux and see how it tastes! Thank you for your advice, we can learn from each other* !