Search

This paper reports the performance of a molten carbonate fuel cell (MCFC) fed directly with liquid fuels referenced against results with hydrogen fuel in experiments conducted by the research team. Alcohols have greater energy density than pure hydrogen in normal conditions and, if presented as biofuels, the MCFC can be deemed a renewable energy source. For evaluation purposes various alcohols occurring in standard conditions in the liquid state were used for electricity generation in the MCFC: methanol, ethanol, propanol, butanol and glycerol. Since these alcohols can be subjected to steam reforming when mixed with water in specific ratios, they can be delivered directly in the liquid state to the fuel cell, where hydrogen is released and used to produce electricity and heat. The alcohols were mixed with water in ratios of 1:2, 1:3, 1:4. The results were compared to the MCFC fed with pure hydrogen as a fuel. In terms of power referenced to hydrogen (100%), the maximums achieved were 78% for butanol, 80% for glycerol, 83% for propanol, 86% for ethanol and 93% for methanol in comparison to the same amount of hydrogen delivered to the fuel cell in ideal steam reforming situation. Threats such as carbon deposition on the fuel cell surface were also evaluated. • MCFC fed directly with various mixtures of alcohols and water have been studied. • The steam reforming of mixtures of alcohols and water generates energy. • Temperature and anode material provide the necessary conditions for steam reforming. • Maximum power compared to hydrogen fuel for various fuels ranges between 78 and 93%. • Carbon deposition in the anode channel of commercial units can be a problem. [ABSTRACT FROM AUTHOR]

Abstract: In this paper the steam reforming of bioalcohols over Ni and Pt catalysts supported on bare Al2O3 and La2O3 and CeO2-modified Al2O3 to produce H2 was studied. Catalytic activity results showed that the glycerine and the intermediate liquid products may hinder the ethanol adsorption on metal active sites of the catalysts, especially at temperatures below 773 K. In fact, ethanol conversion was lower than glycerine conversion in the steam reforming reaction at low temperatures. H2 chemisorption revealed that La2O3 doping of the Ni/Al2O3 catalyst improved the metal dispersion providing a better behaviour to the Ni/Al2O3-O2 catalyst towards H2 production. In the case of Pt catalysts, the good reducibility and the H2 spillover effect provided to the Pt/Al2O3-O1 catalyst the capacity to produce higher H2 yields. The comparison of Pt and Ni catalyst activities showed that the Pt catalysts produced lower H2 yields. This can be attributed to the lower Pt loading as compared to the metal content of the Ni based catalysts. [Copyright &y& Elsevier]

Abstract: In this paper, direct alcohol fuel cells’ thermodynamics parameters were calculated by means of analytical formulas using thermodynamic data. The effect of temperature on reversible efficiency, electromotive force and specific energy for fuel cells supplied with alcohols having from one to five carbons was studied in the range between 298.15 and 1300 K. All parameters were also compared with those of hydrogen fuel cell. It was found that reversible efficiency, electromotive force and specific energy are a function of the amount of carbon atoms in the fuel and a function of temperature. In addition, alcohol’s structure influences fuel cells’ parameters too. We have found that there is a competition between hydrogen, ethanol and methanol at standard conditions, while methanol, ethanol, propanol isomers, 2-methylpropan-1-ol and butan-2-ol, as classified, appear more indicated than hydrogen at more elevated temperature. Therefore, the approach presented here can be considered as sufficient enough for a primary choice of an alcohol that could be used in fuel cells in the future. [Copyright &y& Elsevier]