Background
Florida Distillers Company is based in Auburndale Florida. Their facilities extracted, concentrated, containerized, stored, and shipped citrus and cane molasses-based products. These main product is the production of citrus and cane molasses-based spirits with the added benefits of producing livestock feed supplement, vinegar, cooking wines, and other co-products.
Process Description
(see graphic)The distillery received over 70 000 tons a year of citrus and cane molasses by tanker truck and rail car, which was unloaded into bulk storage tanks. These tanks fed the molasses into a network of batch fermentation reactors, where it was diluted with water to the desired degree Brix. If the amount of available sugar was too high or too low, the natural fermentation was inhibited which would result in the alcohol content being too low. As the diluted molasses entered the fermenter, pectinase (an enzyme) was added to improve viscosity and reduce foaming, and cultured yeast was added to begin the fermentation.
During fermentation, heat was released by the exothermic conversion of fruit sugars to ethanol and carbon dioxide, and the batch temperature was allowed to increase from 70°F to 95°F. At higher temperatures, bacteria are more active and yeast less active. Bacteria attack the sugars and convert them into lactic acid, an undesirable product. Potable well water at 70°F removed the generated heat by circulating on the outside of the inner vessel wall, and each fermenter required a flow of about 30 gal/min during the peak period. The temperature increase of the well water was limited to 25°F.
Upon completion of the fermentation cycle, the alcohol mixture (solids, water, and 8% alcohol), called beer, was transferred to an intermediate tank, called a beer well, for holding. From the beer well, the beer passed through a preheater, where alcohol vapors leaving the still warmed the beer, and then to a beer still. As the beer dropped down the still column, vapors (mostly steam) rose from the bottom of the still. These vapors stripped the alcohol from the beer, left the top of the still, and were condensed back into a liquid containing approximately 80% alcohol. The liquid, called hi-wine, was pumped to a designated intermediate storage tank, ready for final distillation.
Meanwhile, stillage and water were removed from the bottom of the beer still and pumped into intermediate tanks. The stillage was then pumped to an evaporator where it was concentrated into nonalcoholic syrup, called residuum, that was shipped offsite either by tanker truck or rail car as a livestock feed supplement.
Hi-wine was pumped from the storage tank to the aldehyde column. The principal function of this column was to separate low boiling impurities from the main alcohol feed stream to yield a distillate that is relatively impurity free. Impurities that had a lower boiling point than that of ethanol were removed from the top of the column; those that were soluble in water and had a higher boiling point than that of ethanol were withdrawn from the bottom of the column.
The distillate from the aldehyde column was condensed and pumped to the rectifying column, which concentrated the ethanol and removed any remaining impurities. The rectifying column yielded a final product of 190 proof (95%) alcohol that was pumped to designated blending tanks before entering the bottling operation.
In the blending tank, the 190 proof alcohol was diluted with demineralized water to the final alcohol content, and then appropriate flavorings and colorants were added to produce the desired final product, which were rums, tequilas, and vodkas.
Pollution Prevention Improvements
The management realized early on that pollution prevention not only protects the environment, but is synonymous with cost reduction.
Results
Above and Beyond
Florida Distillers also has taken this opportunity to go above and beyond the scope of their P2 projects. At this time they are investigating ways to improve their recycling technologies, wastewater treatment and overall efficiency of their facilities.