KINETICS OF CONTINUOUS FERMENTATION AND STRIPPING OF ETHANOL

A pilot plant consisting of a 30-liter fermenter, and a 10-cm packed c olumn with a blower and condenser to recover ethanol vapors was operat ed continuously for 185 days. On-line washing of the packing in the co lumn twice weekly with condensed ethanol from the process (approximate ly 45% v/v) controlled fouling by attached yeast cells. Steady-state g lucose consumption rates of up to 800 gh(-1), condensed ethanol produc tion rates of up to 26 Vday, and consistently high ethanol yield of ap proximately 0.50 gg(-1) glucose were observed. Data from the pilot pla nt showed that the primary inhibitory effect of ethanol on the steady- state fermenter performance was to decrease the cell yield, while the specific glucose consumption rate was almost unaffected by ethanol con centrations up to 65 gl(-1). A new kinetic model is introduced to repr esent these effects.