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Abstract: The continuous increasing in biodiesel production by transesterification process is leading to an excess of glycerol production as a byproduct. The utilization of this huge amount of glycerol appears as a not easy solvable problem and thus several authors have proposed alternative ways. The integration of the main production process with a glycerol feed molten carbonate fuel cells bottoming cycle, to satisfy plant energy requirements, seems to be one of the most promising one. The proposed paper reports the main results obtained by authors in the framework of an investigation on a possible use of glycerol as energy sources for a real pilot plant for biodiesel production. An overall evaluation of worldwide biodiesel production plants was made and especially about the production capacity in European Union in the last decade. To make a more detailed study, authors were taken into account a real production plant. After a preliminary step, purported to plant mass and energy flows determination, authors considered the integration of a bottoming cycle based on: (i) steam reforming of glycerol for syn-gas production; (ii) molten carbonate fuel cells (MCFC) system supplied by syn-gas for heat and electricity production. A mathematical model, based on experimental data, has been developed to calculate mass and energy balances for the proposed plant lay-out as well as plant energy efficiency enhancement has been determined. Results have evidenced the feasibility of this process and demonstrated that plant integrated with bottoming cycle can reach a very high level of energy self-production. [Copyright &y& Elsevier]

Abstract: Ethanol reforming over MgO and Ni supported catalysts in molten carbonate fuel cell (MCFC) simulated operative conditions has been investigated. Results revealed that an optimum ratio (ATR condition) exists to enhance the performance of both catalysts which otherwise significantly deactivate mainly due to the coke formation. Oxygen contributes to depress coke formation but in some cases promotes acetaldehyde formation specially on catalysts. Very high selectivity in steam reforming (SR) were obtained on both Ni/MgO and catalysts by operating at while in ATR conditions a decrease in hydrogen selectivity was observed at high GHSV only since reactions involved in the reaction mechanism are not at equilibrium. [Copyright &y& Elsevier]

The catalytic behavior of the bare and K-promoted 21% Ni/MgO catalyst in the ethanol steam reforming at MCFC operative conditions has been investigated. The effect of K loading (1–3 wt.%) on the catalytic activity, stability and coking rate have been addressed. K addition stabilizes Ni catalyst mainly by depressing the metal sintering, while coke formation does not seem to be influenced by alkali addition. Endurance test (500 h−1) performed at 20,000 h−1 allows foresee a very long catalyst life in the case of practical application. High H2 productivity (>5 mol H2/mol fed ethanol) was obtained. A change in the electronic properties of the active phase accounts for the effect of K addition on the catalytic behavior of the Ni/MgO catalyst. [Copyright &y& Elsevier]

H2 production by ethanol steam reforming in simulating molten carbonate fuel cell (MCFC) conditions was explored. Ni/MgO catalysts exhibit very high selectivity to H2 and CO2 as a consequence of their low tendency to promote carbon monoxide methanation and ethanol decomposition reactions. Coke formation is strongly depressed due to the benefits induced by the use of basic carrier which positively modify the electronic properties of supported Ni. [Copyright &y& Elsevier]

This study investigates on the efficiency of integrated reformer-MCFC system. Performances of a Ni catalyst working under steam reforming conditions of three different bio-fuels (biogas, ethanol and glycerol) are experimentally evaluated. Reformers outlet stream were applied as fuel for a MCFC stack in order to estimate the total integrated system efficiencies. It is found that the large amount of heat (20%–54% of the inlet fuel – LHV basis) is employed for the reforming of the biofuel during the heating phase of inlet stream to the reforming operative temperature. Moreover, among the examined biofuels the highest amount of externally supplied energy (∼79% of the inlet fuel – LHV basis) is wasted in the fuel processor unit for the steam reforming of ethanol, mostly due to the high amount of the water required (S/C = 4.2 mol/mol). Finally, it is also found that the combined biogas reformer-MCFC system is exhibited the highest electrical efficiency (76%). [ABSTRACT FROM AUTHOR]

Abstract: The paper reports the main results of an investigation on biogas reforming process developed for an integration with high temperature fuel cells systems. Experimental activities have been developed to determine performances of a nickel catalyst in different biogas reforming conditions have been investigated. Attention has been addressed toward the effect of gasifier agents (CO2, H2O and O2) on outlet stream composition and carbon deposition on catalytic surface. Previously, the carbon formation rate in dry and steam reforming reactions apply to a biogas stream (CH4/CO2–60/40vol%) has been evaluated using Aspen plus chemical processor simulator in order to define the operative conditions limit and to selected the best one. A mathematical model, based on experimental data, has been developed to compare the polarization curves of a MCFC mono-cell fed with three different syngas compositions obtained by biogas reforming section in order to find out the best operational conditions for the two integrated systems (MCFC/fuel processor). A parallel trend of the the polarization curves have been obtained due to the assumptions considered for the model developing, as: (i) inlet gas composition effects on ohmic and activation loses are negligible; (ii) diffusional losses are dependent by gas compositions; (iii) diffusional losses are negligible in the graphic sections characterized by low current density. [Copyright &y& Elsevier]

Abstract: The influence of the metal precursor on the catalytic behaviour of Rh/MgO catalysts in steam reforming of ethanol was investigated. Rhodium nitrate and acetylacetonate, having different chemical properties, have been used as hydrophilic and hydrophobic precursors, respectively. More highly dispersed catalysts were obtained using Rh-nitrate, while catalysts prepared with Rh-acetylacetonate show higher stability being generally less affected by coke formation. Catalytic tests performed at molten carbonate fuel cell (MCFC) operative conditions clearly show a structure-sensitive reaction since the turnover frequency (TOF) significantly increases with the mean Rh particle size. Thermodynamic considerations on the basis of the outlet composition allowed to calculate the experimental equilibrium constant for (i) methane steam reforming (MSR), (ii) water–gas shift (WGS), (iii) methane pyrolysis and (iv) Boudouard reactions. By comparing with the equilibrium provided mass action ratios , we suggest that only WGS is fully equilibrated and that coke is formed mainly through methane pyrolysis. [Copyright &y& Elsevier]