(395a) Adsorption Equilibrium Studies of Bio-Based Fermentation Broth (Acetone, Butanol, and Ethanol) Onto Immobilization of Starch Sorbents

Adsorption Equilibrium Studies of Bio-Based Fermentation Broth (Acetone, Butanol, and Ethanol) onto Immobilization of Potato Starch Sorbents and ZSM-5

Bio-based butanol has superior properties when compared to ethanol to be the gasohol and is gradually considered to be an important biofuel from the biomass fermentation. These properties include higher calorific value, low vapor pressure, low freezing point and miscibility with gasoline and diesel. In this context, in 2007, DuPont (US) and BP (UK) announced their plans to produce bio-butanol to be used as a new gasoline extender. [1] 1-Butanol can be produced by non-food products of fiber fermentation by Clostridium acetobutylicum or C. berijerinckii with acetone and ethanol as by-products. This acetone-butanol-ethanol (ABE) fermentation process used to be the main process for industrial production of butanol. The ABE solvent concentration is 20 g/L of which 1-butanol is only 8-13 g. As expected, the energy cost for traditional distillation to recover 1-butanol will be very high. The adsorption using silicalite (Al-free or high Si/Al zeolites) is the most energy efficient method compared to pervaporation, gas stripping and liquid-liquid extraction.[2]

Therefore, in this study, the high Si/Al ratio zeolites, the self-made silica immobilized starch sorbents and their mixtures will be conducted in our laboratory by using the gravimetric adsorption equilibrium apparatus and the dynamic adsorption system to evaluate the competitive adsorption behavior of 1-butanol with other compounds in the ABE solution. The results of this study can be applied to develop a high effectiveness industrial process of butanol recovery from ABE fermentation solution.

In the first year of this study, the selected sorbents will be used to adsorb 1-butanol, acetone, ethanol and water vapor for gas-phase single-component adsorption equilibrium study and analysis by our gravimetric adsorption equilibrium apparatus. The isotherm data were obtained in this study as well as the development of regression models for the isotherm data.

In the second year of this study, our dynamic adsorption system will be modified to allow the control of the required operating parameters. The breakthrough curves of the adsorption of each compound in ABE solution by the selected sorbent in a packed column will be obtained in this study and the effect of each operating parameter on the product concentration of 1-butanol will be discussed. It is important for the design of an industrial butanol recovery adsorption system form ABE solution.