Liquid biofuel production from volatile fatty acids

摘要: The production of renewable fuels and chemicals reduces the dependency on fossil limits increase CO2 concentration in atmosphere only if a sustainable feedstock an energy efficient process are used. thesis assesses possibility to use municipal industrial waste as biomass have little no competition with food production, save greenhouse gasses emissions. Waste is complex substrate diverse composition high water content. It can be homogenized without losing its initial value by anaerobic conversion volatile fatty acids. Using VFA gives opportunity cheap abundantly present residues fuel chemical instead sugar containing crops or vegetable oil. This describes feasibility convert compounds higher content using mixed culture fermentations eliminating oxygen and/or increasing carbon hydrogen At pressure, protons electrons release via reduction organic products such becomes thermodynamically more attractive. Three reactions were studied: hydrogenation alcohol 1) 2) electrode electron donor, 3) chain elongation ethanol. Based concentration, rate efficiency, acetate ethanol was best technique into fuel. In continuous flow CSTR, 10.5 g L-1 caproic acid 0.48 caprylic produced at specific MCFA activity 2.9 caproate 0.09 caprylate per gram VSS d-1. selectively removed calcium precipitation solvent extraction ethyl hexanoate petroleum ether. Microbial characterization revealed that microbial populations stable dominated relatives Clostridium kluyveri. could also reduced alcohols. Acetic, propionic butyric acids biohydrogenated acetic electrode. Observed concentrations 0.62 ethanol, 0.49 propanol 0.27 n-butanol. Methanogenesis successfully inhibited after thermal pre-treatment incubated pH 6, while enhanced. second study, (0.084 L-1) cathodic compartment bioelectrochemical system, which transport mediated methyl viologen. cathode very short term, since mediator irreversibly reacted surface cathode. Of two processes, biohydrogenation elongation, dominant consumes medium With this technology, wet converted biofuels efficient. technology promising due good separation properties acids, produce them rates comparable other conversions.