The transportation sector is a major contributor to green house gas (GHG) emissions. It is widely accepted that immediate action is required before irreversible damage is caused to our environment. There is a need to progressively move to renewable energy sources. Biomass, which typically uses approximately the same amount of CO2 during growth as the CO2 generated during its consumption, can advantageously serve as a renewable source of energy. Bio-ethanol produced from cellulosic biomass can mitigate the net CO2 released for the transportation sector. Biomass can potentially be produced from energy crops and other agricultural materials.

During the fermentation process, it is not feasible to go above 5-6 % (w/w) ethanol when fermenting xylose to ethanol with the currently available technology. In the research described herein, it is proposed to continually remove the ethanol from the fermentor by adsorption, to shift the fermentation towards the more rapid production of ethanol to reduce the load of the distillation column downstream in the bio-ethanol production.

Adsorption of ethanol from aqueous solution by activated carbon and ZSM-5 adsorbents was performed in a column-recirculation system to determine the effective adsorption isotherm. The measured capacity in these experiments was lower than experiments performed in previous well mixed batch systems over the same concentration range. The effect of adsorbent attrition is thought to play a role in the capacity discrepancy as particle breakdown was noted in the well mixed batch systems. The effect of the particle size is also discussed.

A model based on finite difference method is presented for the purpose of mass transfer parameter estimation in batch systems and in breakthrough column studies. The applicability of breakthrough simulations based solely on batch kinetic experiments and column-recirculation isotherms is discussed.

A rough economic analysis of the process based on the preliminary data is also presented.