The Production Of Biobutanol From Biomass Via A Hybrid Biological Chemical Process

Biobutanol use as a fuel began in the late 19th century. Problems remain in economic viability. A review of the state of the art and need for technical advances is presented. The technical potential of producing biofuel from a naturally occurring macroalgae was studied. The algae grow in Jamaica Bay, New York City, in contaminated water. The process consisted of mechanical harvesting, drying, grinding, and acid hydrolysis to form an algal sugar solution. Clostridium beijerinckii and C. saccharoperbutylacetonicum were used in an acetone butanol ethanol (ABE) fermentation to make butanol. Fermentation was followed by distillation Butanol concentrations during fermentation reached 4 g/L. The recovery of reducing sugars in the media was 0.29 g butanol/g sugar. Feedstock with greater than 7 g/L butyric acid caused death of the butanol-producing bacteria. The kinetics of the production of 1-octadecanol from octadecanoic acid was investigated in a liquid-phase trickle-bed reactor by hydrogenation. The primary reactions occurring in the reactor were the desired conversion of octadecanoic acid to 1-octadecanol and the subsequent undesired conversion of 1-octadecanol to octadecane. A series-parallel kinetics model first order in acid and zero order in hydrogen was developed to predict these two reactions. The activation energies of the reactions were 63.7.8 and 45.6 kJ/mole, respectively. The conversion of octadecanoic acid and the selectivity to the desired product as functions of temperature, space velocity, and inlet octadecanoic acid concentration were then estimated. The model predicts maximum productivity of 1-octadecanol at higher temperatures and short residence times. Parametric plots show productivity to be ≥0.48 g 1-octadecanol/g octadecanoic acid at 566 °F and a 0.1 h residence time. The model from the 1-octadecanoic acid study was fitted to several sets of data for the hydrogenation of butyric acid to butanol in the temperature regime of 300-400 °F and pressures of 700-1000 psig. The model failed to accurately predict the final concentrations of 1-butanol and butane. Reasons for this are suggested and future work to fix this problem is presented and discussed.