Hydrogen production via glycerol dry reforming over La-Ni/Al 2O3 catalyst (original) (raw)
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J Energy Chemistry, 2014
In the current paper, dry (CO 2 )-reforming of glycerol, a new reforming route, was carried out over alumina (Al 2 O 3 )-supported, non-promoted and lanthanum-promoted nickel (Ni) catalysts. Both sets of catalysts were synthesized via a wet co-impregnation procedure. Physicochemical characterization of the catalysts showed that the promoted catalyst possessed smaller metal crystallite size, hence higher metal dispersion compared to the virgin Ni/Al 2 O 3 catalyst. This was also corroborated by the surface images captured by the FESEM analysis. From temperature-programmed calcination analysis, the derivative weight profiles revealed two peaks, which represent a water elimination peak at a temperature range of 373 to 473 K followed by nickel nitrate decomposition from 473 to 573 K. In addition, BET surface area measurements gave 85.0 m 2 ·g −1 for the non-promoted Ni catalyst, whilst the promoted catalysts showed an average of 1% to 6% improvement depending on the La loadings. Significantly, reaction studies at 873 K showed that glycerol dry reforming successfully produced H 2 . The 2%La-Ni/Al 2 O 3 catalyst, which possessed the largest BET surface area, gave an optimum H 2 generation (9.70%) at a glycerol conversion of 24.5%.
Production of CO-rich hydrogen gas from glycerol dry reforming over La-promoted Ni/Al2O3 catalyst
International Journal of Hydrogen Energy, 2014
Lanthanide Syngas a b s t r a c t Dry reforming of glycerol has been carried out over alumina-supported Ni catalyst promoted with lanthanum. The catalysts were characterized using EDX, liquid N 2 adsorption, XRD technique as well as temperature-programmed reduction. Significantly, catalytic glycerol dry reforming under atmospheric pressure and at reaction temperature of 1023 K employing 3 wt%LaeNi/Al 2 O 3 catalyst yielded H 2 , CO and CH 4 as main gaseous products with H 2 :CO < 2.0. Post-reaction, XRD analysis of used catalysts showed carbon deposition during glycerol dry reforming. Consequently, BET surface area measurement for used catalysts yielded 10e21% area reduction. Temperature-programmed gasification studies with O 2 as a gasification agent has revealed that La promotion managed to reduce carbon laydown (up to 20% improvement). In comparison, the unpromoted Ni/Al 2 O 3 catalyst exhibited the highest carbon deposition (circa 33.0 wt%).
Experimental Investigation of Steam Reforming of Glycerol over Alumina Supported Nickel Catalysts
The growing demand of hydrogen needs renewable sources of raw materials to produce it. Glycerol, by-product of biodiesel synthesis, could be a bio-renewable substrate to obtain hydrogen. Momentous amount of glycerol is produced as a byproduct during bio-diesel production by the transesterification of vegetable oils, which are available at low cost in large supply from renewable raw materials. As hydrogen is a clean energy carrier, conversion of glycerol to hydrogen is one among the most attractive ways to make use of glycerol. Production of hydrogen from glycerol is environmentally friendly because it adds value to glycerol generated from biodiesel plants. In this study, the catalytic production of hydrogen by steam reforming of glycerol has been experimentally performed in a fixed-bed reactor. The performance of this process was evaluated over 5wt%, 10wt%, and 15wt% Ni/Al2O3. The catalysts were prepared by the wet impregnation technique. For a comparative purpose, the steam reforming experiments were conducted under same operating conditions, i.e., reaction temperature ranging from 700°C to 900°C, atmospheric pressure and 1:9 glycerol to water molar ratio. Also the effect of glycerol to water ratio, metal loading, and the feed flow rate (space velocity) was analysed. The results showed that the hydrogen production increased with the increase in the treatment temperature. The highest amount of hydrogen produced was attained over 15wt% Ni/Al2O3 at 850 °C at 1:9 glycerol to water molar ratio. The catalyst Co/Al2O3,Cu/Al2O3 were prepared by wet impregnation technique and need to do activity test and compare the results with Ni/Al2O3.
Syngas production from glycerol-dry(CO2) reforming over La-promoted Ni/Al2O3 catalyst
Renewable Energy, 2015
A 3 wt% La-promoted Ni/Al2O3 catalyst was prepared via wet co-impregnation technique and physicochemically-characterized. Lanthanum was responsible for better metal dispersion; hence higher BET specific surface area (96.0 m2 g−1) as compared to the unpromoted Ni/Al2O3 catalyst (85.0 m2 g−1). In addition, the La-promoted catalyst possessed finer crystallite size (9.1 nm) whilst the unpromoted catalyst measured 12.8 nm. Subsequently, glycerol dry reforming was performed at atmospheric pressure and temperatures ranging from 923 to 1123 K employing CO2-to-glycerol ratio from zero to five. Significantly, the reaction results have yielded syngas as main gaseous products with H2:CO ratios always below than 2.0 with concomitant maximum 96% glycerol conversion obtained at the CO2-to-glycerol ratio of 1.67. In addition, the glycerol consumption rate can be adequately captured using power law modelling with the order of reactions equal 0.72 and 0.14 with respect to glycerol and CO2 whilst the activation energy was 35.0 kJ mol−1. A 72 h longevity run moreover revealed that the catalyst gave a stable catalytic performance.
RSC Advances, 2014
Glycerol steam reforming, which is a potential technology for hydrogen production in fuel-cell applications, is of great interest to researchers in recent years. Using aqueous glycerol, which is a byproduct in biodiesel production, as a direct feed for steam reforming is a promising method to produce hydrogen. Ni (5, 10, 15, 20 and 25 wt%) loaded on commercial γ-Al2O3 by the impregnation method is used to study steam reforming of glycerol. The catalyst was characterized by XRD, EDAX, BET surface area, TPR, NH3-TPD, TEM, CHNS and Raman techniques. The catalysts are evaluated on time streams for the effect of Ni loading, temperature, and glycerol-to-water mole ratio (GWMRs). Under the parameters investigated, 15 wt% Ni/γ-Al2O3 was found to be the most promising catalyst in terms of glycerol conversion and hydrogen production with minimum coking. The characterization of the catalysts clearly establishes that interaction of Ni2+ with γ-Al2O3 support, Ni2+ reducibility, particle size, and acidity of the support are seen governing the stable activity of the catalysts. Thus, a structural activity correlation has been established on the Ni/γ-Al2O3 catalysts.
Chinese Journal of Catalysis, 2016
The influence of the synthesis method parameters used to prepare nickel-based catalysts on the catalytic performance for the glycerol steam reforming reaction was studied. A series of Al2O3-supported Ni catalysts were synthesized, with nickel loading of 8 wt%, using the incipient wetness, wet impregnation, and modified equilibrium deposition filtration methods. The catalysts' surface and bulk properties were determined by inductively coupled plasma (ICP), N2 adsorption-desorption isotherms (BET), X-ray diffraction (XRD), scanning electron microscopy (SEM), transmission electron microscopy (TEM), and temperature-programmed reduction (TPR). Used catalysts were characterized by techniques such as elemental analysis and SEM in order to determine the level of carbon that was deposited and catalyst morphology. The results indicated that the synthesis method affected the textural, structural and surface properties of the catalysts, differentiating the dispersion and the kind of nickel species on alumina's surface. The formation of nickel aluminate phases was confirmed by the XRD and TPR analysis and the β-peak of the Ni/Al-edf catalyst was higher than in the other two catalysts, indicating that the nickel aluminate species of this catalyst were more reducible. Both Ni/Al-wet and Ni/Al-edf catalysts showed increasing CO2 selectivities and approximately constant CO selectivities for temperatures above 550 °C, indicating that these catalysts successfully catalyze the water gas shift reaction. It was also confirmed that the Ni/Al-edf catalyst had the highest values for glycerol to gaseous products conversion, hydrogen yield, allyl alcohol, acetaldehyde, and acetic acid selectivities at 650 °C and the lowest carbon deposition of the catalysts tested. The correlation of the catalysts' structural properties, dispersion and reducibility with catalytic performance reveals that the EDF method can provide catalysts with higher specific surface area and active phase's dispersion, that are easier to reduce, more active and selective to hydrogen production, and more resistant to carbon deposition.
Processes, 2019
Nowadays, the massive production of biodiesel leads to a surplus of glycerol. Thus, new applications of this by-product are being developed. In this study, glycerol steam reforming was carried out with Ni catalysts supported on Al2O3 rings and La-modified Al2O3. The catalysts were characterized by N2 physical adsorption, X-ray diffraction, X-ray photoelectron spectroscopy, scanning electron microscopy, and thermogravimetry. Both catalysts were effective in glycerol steam reforming. However, Ni/Al2O3 activity decreased over reaction time. Ni/La2O3/Al2O3 showed the best stability during the reaction. In addition, the activity of the modified support, La2O3/Al2O3, was evaluated. The modification of the support lent catalytic properties to the solid. Some conditions such as catalyst arrangement (catalyst in the first or second reactor), space velocity, and reaction temperature were studied. The highest hydrogen production was obtained when half the amount of the catalyst was located in ...
Topics in Catalysis, 2008
Hydrogen production from glycerol reforming in liquid (aqueous phase reforming, APR) and vapor (steam reforming SR) phase over alumina-supported nickel catalysts modified with Ce, Mg, Zr and La was studied. Characterization of catalysts by temperature programmed reduction and XPS analyses revealed important structural effects: (i) the intercalation of Mg between nickel and alumina that inhibited the alumina incorporation to nickel phases, (ii) the close contact between Ni and Zr phases and, (iii) the close surface interaction of La and Ce ions with NiO phases. The catalytic activity of the samples studied in this work clearly indicated the different catalyst functionalities necessary to carry out aqueous-phase and vaporphase steam reforming of glycerol. For aqueous phase reforming of glycerol, the addition of Ce, La and Zr to Ni/ Al 2 O 3 improves the initial glycerol conversions obtained over the Ni/Al 2 O 3 supported catalyst. It is suggested that the differences in catalytic activities are related with geometric effects caused by the decoration of Ni phases by Ce and La or by the close interaction between Ni and Zr. In spite that nickel catalysts showed high APR activities at initial times on stream, all samples showed, independently of support, important deactivation rates that deactivate the catalysts after few hours under operation. Catalysts characterization after APR showed the oxidation of the active metallic Ni during reaction as the main cause of the observed deactivation. In the case of the glycerol steam reforming in vapor phase, the use of Ce, La, Mg and Zr as promoters of Ni based catalysts increases the hydrogen selectivity. Differences in activity were explained in terms of enhancement in: surface nickel concentration (Mg), capacity to activate steam (Zr) and stability of nickel phases under reaction conditions (Ce and La).
Steam Reforming of Glycerol for Hydrogen Production Over Supported Nickel Catalysts on Alumina
Journal of Nanoscience and Nanotechnology, 2013
The experiment was carried out to produce hydrogen through steam reforming of glycerol over nano-sized Ni catalysts supported on alumina (Al 2 O 3). The catalysts were characterized by BET surface area, metal dispersion, XRD, TPR, NH 3-TPD and SEM. 15 wt% Ni/Al 2 O 3 catalysts presented carbon nano fiber after the catalyst was used. However, when the Ni loading was higher than that of 15 wt%, the catalytic activity reduced, and the increase of the Ni particle size and the formation of graphitic carbon occurred. The Ni/SiO 2 (70)-Al 2 O 3 with the high surface area and the small Ni particle size promoted the catalytic activity and could easily reduce from NiO to Ni, inhibiting the formation of NiAl 2 O 4 .