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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: Glycerol steam reforming on Rh and Ni supported catalyst was investigate in view to produce syn-gas to feed a high temperature fuel cell system (SOFC-MCFC). Results obtained revealed that glycerol is subjected to pyrolysis phenomena and at temperature higher than 720K drastically decomposes before to reach the catalyst surface. Rh/Al2O3 catalyst resulted to be more active and stable than Ni supported catalysts but independently from the catalyst used (Rh or Ni) and temperature investigated, the reaction is affected by coke formation mainly promoted by the large presence of olefins formed by glycerol thermal decomposition. Even if for thermodynamic reasons the hydrogen production should be favored by operating at high temperature, results obtained demonstrate that it is more convenient to operate at temperature not higher than 923K, since higher reaction temperature promotes the formation of encapsulated carbon which negatively reflects on catalyst stability. [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 performance of MgO supported Pd, Rh, Ni and Co catalysts in the steam reforming of simulated bio-ethanol at MC fuel cell operative conditions (T=650 °C) has been investigated. Rh/MgO shows the best performance both in terms of activity and stability, however, it seems not to be so selective towards H2 production. Ni, Co and Pd catalysts are affected by deactivation mainly due to metal sintering. Ni/MgO displays the best performance in terms of H2 selectivity (>95%). A very low coke formation rate was observed on Rh/MgO catalyst, however, even on Ni/MgO catalyst coke formation occurs with modest rate. Kinetics measurements have shown that a significant difference in terms of metals specific activity exist: Rh sites resulted to be 2.2, 3.7 and 5.8 times more active than Pd, Co and Ni, respectively. [Copyright &y& Elsevier]

The effects of alkali addition (e.g. Li, Na, K) on the behavior of Ni/MgO catalyst in the bio-ethanol steam reforming have been investigated. Li and Na promote the NiO reduction but negatively affect the dispersion of the Ni/MgO catalyst, whereas K does not significantly affect either morphology or dispersion. Li and K enhance the stability of Ni/MgO mainly by depressing Ni sintering. Coke formation on bare and doped catalysts occurs but with orders of magnitude lower rates than those claimed for Ni supported on an acidic carrier. The peculiar influence of the mean Ni particle size on the turnover frequency (TOF s-1) has been explained by invoking a structure-sensitive character of the ethanol dehydrogenation reaction considered as being the first step of the reaction which evolves according to the following mechanism: ethanol hydrogenation → acetaldehyde decomposition → steam reforming of methane and water gas shift reactions. [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]

Planar polymeric membranes with hydrophilic, hydrophobic and composite (coupled or thermowelded) structures have been prepared and tested in an experimental lab-scale plant by using different liquid absorbents (amines, carbonate, H2O) as “carrier” with the aim to optimize the process of CO2 separation from other gas. The effect of nature of the membranes, differential pressure between gas/liquid phases and type and concentration of the absorbent were investigated as well as the carrier transport mechanism. The best performances (in terms of CO2 permeability) have been determined for coupled membranes. Moreover, the experimental results have shown that, between the studied carriers, the 2-etanolamine is the type of adsorbent with the greater affinity toward the CO2. [Copyright &y& Elsevier]

Steam reforming of ethanol, in simulated MCFC operative conditions was investigated over MgO supported Ni and Co catalysts. Ni/MgO catalysts exhibit higher activity and selectivity to H2 than Co/MgO catalysts because of the lower tendency of Ni to oxidize during reaction and to promote carbon monoxide methanation and ethanol decomposition reactions. Coke formation was strongly depressed due to the benefits gained through the use of basic carrier (MgO). Endurance tests carried out at low gas hourly space velocity (10,000 h−1) for 630 h showed that Ni/MgO catalyst possesses adequate characteristics to be proposed as an efficient catalytic system for the production of hydrogen for MCFC. [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]

Investigations have been carried out to study the influence of low operating temperature (873 K) on the decay mechanisms that affect the endurance of a molten carbonate fuel cell. An experiment has been performed for several thousands of hours of continuous operation at a current density of 160 mA cm-2 on a bench-scale cell to evaluate the electrochemical performance parameters and morphological characteristics of spent components. The tested components were a traditional LiAlO2 matrix, charged by a mixture of Li/K, NiO cathode and Ni/Cr anode. During the test, measurements of temperature, pressure, flows, cell internal resistance, current and voltage have been taken continuously, as well as gas chromatography analyses. At theend of the experiment, the cell showed an increase in internal resistance of 07376 omega cm-2 and a lowering of open-circuit voltage of 30 mV. The electrolyte distribution in the components indicated an excess of empty pores in the tile structure with a filling degree of 7278%. By contrast, the anode retained a filling degree of 6473%, while the cathode appeared under partial flooding condition witha filling degree of 4872%. The SEM cross-section view of the cell package (cathode, tile and anode) showed evidence of a process of cathode dissolution and coprecipitation of Ni in a narrow band located almost in the middle of the section. The Ni, Cr, Al and K distribution profiles in the cross-section were investigated by EDAX analysis. [ABSTRACT FROM AUTHOR]

The internal reforming concept has been successfully integrated in molten carbonate fuel cell (MCFC) systems. In this paper, a comparisonbetween the direct (DIR-MCFC) and indirect internal reforming (IIR-MCFC) configurations has been made. This approach, realized through a sensitivity analysis of suitable models, allows the advantages and disadvantages of the two configurations to be evaluated in terms of mass transfer balances and efficiencies. The temperature, steam/carbon ratio, electrical power and useful heat fraction have been found to bethe most important parameters for optimizing the efficiencies of thetwo systems. Moreover, a detailed analysis of the technical problemspresented by the two systems gives meaningful conclusions about their reliability for the production of electricity. [ABSTRACT FROM AUTHOR]

Abstract: Industrial wastes from the semiconductor industry comprise solvent mixtures of organic oxygenated compounds. Steam reforming of three alcohols and three oxygenated molecules (aldehydes and ketones), normally used in the electronics industry, was carried out at 1073K by using a Ni/Al2O3 catalyst. Hydroxyl and carbonyl groups show highly different reactivities and coke formation from molecules containing a hydroxyl group is higher than for those with a carbonyl group. Thermodynamic considerations on the basis of the outlet compositions have allowed calculation of the mass action ratio (MAR) for the main equilibria involved: (i) methane steam reforming (MSR); (ii) water–gas shift reaction (WGSR); (iii) methane pyrolysis (PYR); and (iv) Boudouard reaction (BOUD). We suggest that MARMSR is lower than equilibrium value and excess of methane is always present in the reaction atmosphere. [Copyright &y& Elsevier]

The steam reforming of ethanol on 5% Rh/Al2O3 catalyst has been investigated to produce H2 adequate to feed a molten carbonate fuel cell (MCFC). The influence of reaction temperature, H2O/EtOH molar ratio, gas hourly space velocities (GHSV) and O2 were investigated in order to maximize the hydrogen content at the outlet of ethanol reformer. Endurance tests to assess the feasibility of a FC system fed by simulated bio-EtOH stream (H2O/EtOH molar ratio=8.4) were also performed. Experiments carried out at MCFC operative conditions allowed to obtain a H2 reach mixture close to 60% on dry basis. In steam reforming (SR) conditions an extensive formation of encapsulated carbon was registered while a great benefits, both in terms of catalyst stability and coke formation were evidenced adding 0.4 vol.% of oxygen in the reaction stream. Oxygen however promoted metal sintering. Consideration on reaction mechanism, mainly investigated to distinguish the reaction pathway influencing the H2 production, is reported. [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]

An investigation on the feasibility of producing bio-oil and bio-char fuels from wood chips (White-Pine), a Mediterranean seaweed (Posidonia Oceanica) and a local freshwater alga (Lacustrine Alga) by pyrolysis was carried out. Experiments were performed in a fixed bed reactor at different temperatures (400, 500 and 600 °C). Thermo-gravimetric analysis (TGA/DTG) were used in order to investigate the pyrolytic behavior. Product yields and composition from algal pyrolysis were compared with those obtained from terrestrial biomass. Yields of char were in the range 22–48 wt% for algae and 20–27 wt% for lignocellulosic biomass. Due to the higher ash content (17–38%), the char obtained from algal biomasses had a lower heating value than that from White-Pine chips. By contrast, the oil yields from algae varied between 34 and 55 wt%, whereas yields from lignocellulosic biomass were in the range of 41.4–47.2%. The oil from Posidonia Oceanica showed a high heating value (HHV = 26.1 MJ/kg) close to the value of the oil obtained from White-Pine (30.1 MJ/kg). Chemical composition of liquid samples obtained at 500 °C was analyzed by GC–MS to identify organic functional groups. [ABSTRACT FROM AUTHOR]

In recent years, research efforts on fuel cells have been addressed on the development of multifuel reformers with particular emphasis toward the potential use of non-traditional fuels. Among these, biogas is considered very promising to be used as syngas source for fuel cell system applications. The interest on this hydrogen source is focused mainly to supply high temperature fuel cells (HTFC). This paper reports a wide experimental research investigation on SOFC device supplied by syngas produced with different biogas reforming processes (steam reforming, autothermal reforming and partial oxidation). Thermodynamic simulations have been performed to determine the reformed gas composition varying process, reaction temperature and steam to carbon – oxygen to carbon ratios. Syngas mixtures obtained were experimentally tested in order to evaluate the performance of a SOFC mono-cell. Furthermore, an analysis of the combination: fuel processor with a SOFC stack has been determined in order to assess the total energy efficiency. [ABSTRACT FROM AUTHOR]

Highlights: [•] Ni-based anode supported fuel cell were used to build an SOFC stack fed by biogas. [•] We focus on sulfur compound pollutant effect on fuel cell system. [•] H2S is first removed by adsorption in a zeolites bed plus a ZnO guard bed. [•] The behavior of the sub-sections are monitored by an online MS technique. [•] The 3-cells short stack showed a regular behavior with no signs of degradation. [ABSTRACT FROM AUTHOR]

Abstract: In this study, ceria nanoparticles with well-defined surface states were synthesized in order to enable the study of different ceria surfaces, independently. Ceria nanocubes were shown to expose only (100) surfaces, ceria nanooctahedra only (111) surfaces, and ceria nanorods are more complex, with at least 50% of (110) surfaces, as shown by high-resolution transmission electron microscopy. Temperature-programmed reduction (TPR) by hydrogen performed on these powders shows the following order of reaction temperatures: cubes

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]

Abstract: By means of ultra high vacuum temperature programmed desorption experiments, we studied the influence of oxygen on the decomposition of ethanol over rhodium(111) and (100) single crystal surfaces. Oxygen at low surface coverage (between 0.1 and 0.25 ML) promotes ethanol decomposition and the formation of carbon dioxide, while carbon monoxide production is not significantly affected, with respect to the reaction on clean samples. Oxygen coverage above 0.25 ML hinders hydrogen formation due to the prevalent oxidising action, which leads to water formation. These results are in line with data we obtained for ethanol decomposition over a 5% Rh/Al2O3 catalyst under typical reforming working conditions (i.e. T=923K and P=1bar), thus indicating that an oxidising environment is required in order to avoid carbon poisoning and to promote C2-containing molecules decomposition. On the contrary, excess of oxygen leads to a strong reduction of hydrogen concentration in the reaction products. [Copyright &y& Elsevier]

This study is focused to optimising a bio-ethanols auto-thermal reforming (ATR) process over 5% Rh/Al2O3 catalyst homemade, to produce syn-gas for fuel cell application. The effect of oxygen addition for a given S/C molar ratio ranging from 2.1 to 6.3 at T=923 K was investigated, varying the O2/EtOH molar ratio between 0.2 and 1.1. The results have identified an optimum range where the ethanol conversion is 100%, CH4 and CO productions go down and hydrogen yield reaches a maximum before decreasing because of the prevalent oxidizing action of oxygen. The obtained data, compared with those from steam reforming (SR) process, gave a very clear indication about the potentiality of ATR process. [Copyright &y& Elsevier]

In this review article the analysis of the main problems related to the use of NiO as material for cathodes in Molten Carbonate Fuel Cells (MCFC) is reported. Thus, the most significant evidences of the mechanism of NiO dissolution have been reported as well as its correlation with the basicity of the carbonate melt, composition of the reactants gases and temperature. Some hypotheses described here have been also verified experimentally and the results of this validation are reported. In the final section, we have described the most promising alternative solutions to this problem and the advantages and shortcomings of these alternatives. [ABSTRACT FROM AUTHOR]