Recycling and Refining of Alcohol Derived from Waste Beer Separated from Spent Yeast

Abstract

Spent yeast slush is a by-product of brewing, the yield of which is approx. 1.5% of total beer production. The yeast is separated from the spent yeast slush, which can be utilized generally, while the rest of the waste beer can be used as raw material to produce alcohol. A technique was proposed to recycle and refine alcohol from the waste beer separated from spent yeast. The rough alcohol was recycled from spent yeast after distillation by a continuous column consisting of 28 plates. The flow rate of the waste beer was 11.1 kg/min. The still pressure was 0.12 MPa, and the temperature at the top of the column was 85°C. The rough alcohol obtained was bitter and astringent and was refined using a 50-L batch column. Some parameters were optimized during the refining process of batch distillation. The initial alcohol content was 60%, and the reflux ratio was 3. The foreshot recovery was 3%, while the feints recovery was 14%. The refined alcohol was treated with 0.4% (wt/wt) activated carbon for 24 hr and then analyzed based on Chinese national standard GBT394.2–2008.