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The aim of this work is to exploit the potential of residual biomass, different from the traditional wood feedstock, by thermochemical gasification process. In particular, citrus peels waste of the juice extraction process, was selected since it is a typical local Sicilian residue. The citrus peel conversion performances in air-steam gasification process were evaluated and compared with those obtained with pinewood as feedstock. Experimental activities of air-steam gasification were carried out in a bench-scale fluidized bed reactor at 1023 K, for both citrus peel and pinewood, varying the steam to biomass ratio (S/B). A simulation model of the experimental facility was developed in order to find a useful tool to realize the virtual scale-up of the system with downstream syngas utilization. The cold gas efficiency (CGE) and the net cold gas efficiency (CGEnet) were calculated to define the best gasification conditions. Results showed that using pinewood a very low reactivity can be observed, showing a very low net CGE. The highest net CGE for citrus peel was observed at S/B = 0.5, while for pinewood the addition of water did not improve the net CGE. Finally, an integration of the citrus peel gasification system with a commercial CHP unit was proposed and the efficiencies were evaluated. [ABSTRACT FROM AUTHOR]

This study reports the influence of biogas poisoning on a Ni based catalyst working under steam reforming conditions (atmospheric pressure, T = 1073 K and H 2 O/CH 4 = 2 mol/mol). A biogas stream composed by CH 4 and CO 2 with a ratio 55/45 vol.%, added with different chemical species (H 2 S, hydrocarbons mixture and D5) as contaminants, was used as inlet gas stream. First, effect of poisoning on Ni catalyst were separately evaluated and the boundary concentrations for each contaminants were revealed (0.4 ppm, 200 ppm and 0.5 ppm for H 2 S, hydrocarbons and D5 respectively) to assure Ni stable performances on time on stream (100 h at 50,000 h −1 of GHSV). Successively, a comparison between Ni catalytic behaviors in presence of two combined poisoning in the biogas (H 2 S + Hydrocarbons and Hydrocarbons + D5) was carried out. It was found that the effect of combined poisoning, even though it considered in moderate concentration, is harmful for Ni catalyst activity. Methane conversion on time on stream was reduced from 86% to 40% after 50 h, when the couple of poisoning Hydrocarbons + D5 was added to the inlet gas stream, while a lower deactivation pattern (about 73%) was leaded by couple H 2 S + Hydrocarbons. Both poisoning mixtures promoted coke deposition on Ni catalyst surface (about ≥0.5 mgC/g cat ·h) independently by poisoning chemical characteristics probably due to adsorption/deposition of contaminants on catalytic sites. [ABSTRACT FROM AUTHOR]

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]

Abstract: The present paper deals with the study of the combustion of reforming gas in a small size Internal Combustion Engine. Therefore, mathematical models of both reforming process and internal combustion engine were implemented. In particular, steams reforming of glycerol to produce synthesis gas and spark ignition four strokes ICE were studied. The reforming process mathematical model was verified using experimental data. Synthesis gas was used to feed the ICE with different syngas and engine configuration. On the basis of the comparison with the experimental results, it is possible to state that the mathematical model is validated. Engine performance and pollutant emission evaluation was carried out using the integrated mathematical models with reference to the engine running on standard commercial fuel. The results highlight a reduction in engine performance and, at the same time a reduction of pollutant emissions in terms of CO and CO2. [Copyright &y& Elsevier]

Abstract: In the last decade, production of biogas from biomass degradation has attracted the attention of several research groups. The interest on this hydrogen source is focused on the potential use of this gas as raw material to supply high temperature fuel cells (HTFC). This paper reports a wide research investigation carried out at CNR-ITAE on biogas reforming processes (steam reforming, autothermal reforming and partial oxidation). A mathematical model was developed, in Aspen Plus, and an experimental validation was made in order to confirm model results. Simulations were performed to determine the reformed gas composition and the system energy balance as a function of process temperature and pressure. The value of Gas Hour Space Velocity (GHSV) was selected for calculating compositions at full equilibrium, as it is expected in operative large scale plant. To obtain a realistic evaluation of the reforming processes efficiency, the energy balance for each examined process was developed as available energy of outlet syngas on inlet required energy ratio. The comparison between values of efficiency process gives useful indication about their reliability to be integrate with fuel cell systems. [Copyright &y& Elsevier]

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: 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]

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: 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]

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: 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]

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]

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]