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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: 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]

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]

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]

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]

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]

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]