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Michael L. Reinig Jr.
Nuclear Science and Engineering Institute
University of Missouri-Columbia
Advisors: Dabir S. Viswanath, Tushar K. Ghosh, and S. K. Loyalka
Abstract
Advances in fuel cell technology have been taking place at a rapid pace during the past, particularly fuel cells in the automotive industry. Among the various types of fuel cells, direct oxidation fuel cell (DOFC) based on methanol (direct methanol fuel cell, DMFC) has received considerable attention. Methanol has many disadvantages as a fuel. It has a high fuel crossover rate, toxic, and high vapor pressure because of its lower boiling pointing. For these reasons, other fuels have been investigated, and the one using dimethyl oxalate (DMO) shows significant potential as a DOFC fuel to replace methanol. DMO has a lower fuel crossover rate, higher fuel utilization, is non-toxic, and has a higher boiling point compared to methanol. Feasibility of a DMO DOFC has been experimentally evaluated by Peled et al. Peled et al.'s experimental work employed a methanol optimized catalyst and membrane in the DMO DOFC.
In this investigation, certain thermodynamic evaluations have been carried out to see if improvements in a DMO DOFC are possible. Thermodynamic calculations for the anode reaction: C4H6O4 + 4H2O -> 2CO2 + 7H2, were done using already known experimental data. Additionally, Peled et al.'s fuel cell was an open system, however if future thermodynamic calculations are needed for a sealed DMO DOFC, a model for the pressure of DMO as a function of temperature will be needed. A correlation of the available experimental vapor pressure data fitted the Antoine's equation, and the value of the constants are A = 8.3149, B = 2440.37 and C = -140.933. The data fits the Antoine's equation with a maximum error of ± 0.22 and an average absolute deviation of ± 3.66. Equilibrium constants for the operational temperatures of 333 - 368 K for a DMO DOFC show that the reaction is favorable with an equilibrium constant of 8.69E+11 at 333 K and increases with temperature. Equilibrium composition determination shows that DMO (on a basis of 1 mole of DMO) at equilibrium is 4.01E-6 moles at 333 K and decreases with increasing temperature.
Mike Reinig is an undergraduate student at the University of Missouri in Columbia.
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