Liquid-Liquid Equilibria Studies of Potential Organic Solvents as Ethanol Extractants from Aqueous Solutions
Chemical and Materials Engineering
Recent years have brought concern for the environment to the forefront, specifically with negative impacts of fossil fuels. Jet fuels are estimated to contribute to 2% of CO2 emissions and are predicted to rise. Many alternatives to petroleum based fuels are being explored, including biofuels which have the potential to reduce CO2 emissions by 85%. However, biofuels do not come without challenges. Inevitably, these fuels will have high water content, due to water formed during biological reactions. Unfortunately, water can be damaging to engines, requiring removal for optimum performance rates. Hydrocarbons, such as ethanol, have unideal interactions with water, forming an azeotrope, and cannot be fully separated via simple chemical engineering separations such as distillation, making the process highly energy-intensive and expensive. Liquid-liquid extraction could be a more cost-effective solution, with a proper solvent, because it can be implemented with smaller equipment and lower energy consumption. This project analyzes the effectiveness of using three organic solvents: castor oil, dodecane, and 2-methylcyclohexanol, to extract ethanol from water. Liquid-liquid equilibrium was determined using the cloud point method and data for the three ternary systems was collected using headspace gas chromatography at 25°C. A ternary diagram for each organic solvent, water, and ethanol was obtained. Preliminary liquid-liquid extractions using a laboratory scale mixer-settler were completed with vegetable oil to provide a proof of concept method for the separation ethanol from the aqueous stream. Parameters gleaned from the ternary systems and the preliminary liquid-liquid extractions studies were used to analyze the potency of each solvent in the separation of ethanol and to determine the conditions for the best separation. Ultimately, this work provides new insights into the use of green solvents as possible ethanol extraction agents in liquid-liquid extractions processes.
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Docken, Grace, "Liquid-Liquid Equilibria Studies of Potential Organic Solvents as Ethanol Extractants from Aqueous Solutions" (2020). Honors Theses. 254.
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