Purification and Quality Enhancement of Fuel Ethanol to Produce Industrial Alcohols with Ozonation and Activated Carbon

摘要

The total ethanol production capacity in the US just passed 6 billion gals/year. The production process of ethanol from corn includes corn milling, cooking, enzymatic starch conversion, fermentation and distillation. Food-grade alcohol production requires more care and undergoes costly additional purification to remove volatile organic impurities. These impurities could be of health concern and/or impart unpleasant tastes and odors to beverage alcohol. Multiple distillation steps are usually employed. The additional purification of ethanol to obtain food-grade alcohol adds at least $0.30 per gallon in processing costs. In this research, we tested a novel approach to purify fuel grade ethanol to pharmaceutical and beverage grade. The cost of the proposed treatment process is expected to be less than $0.01 per gallon. We have shown that ozone can oxidize a number of undesirable compounds in ethanol. Furthermore, it was demonstrated that adsorption on granular activated carbon can remove many of the ozonolysis byproducts. All chemical and sensory analyses were completed using solid phase microextraction (SPME) to extract volatile organic compounds from ethanol samples and a multidimensional GC-MS-Olfactometry system to identify impurities and the impact of odorous compounds. To date, we confirmed a significant reduction of some impurities with ozone alone. Ozone and granular activated carbon are very effective in purifying fuel ethanol. Also, we designed a purer ozone generating setup. This setup can provide further purification efficiency on this research. This technology will help the corn milling and ethanol industry and provide an opportunity for improving the long-term sustainability of corn growing and processing.