Carbon Dioxide Dry Reforming of Glycerol for Hydrogen Production using Ni/ZrO2 and Ni/CaO as Catalysts (original) (raw)
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Catalysis for Sustainable Energy, 2013
Nickel catalysts supported on Al 2 O 3 , CeO 2 and ZrO 2 were prepared by wet impregnation method and evaluated in steam reforming of glycerol. The catalysts were characterized by chemical composition, textural analysis, crystalline structure and reducibility. The structural characterization of the catalysts revealed a good dispersion of Ni particles using the Al 2 O 3 support, needing higher reduction temperature. The reactions were performed at 500°C with 10 vol.% glycerol solution in a continuous flow reactor. All catalysts showed conversions close to 100%. The selectivity to gas products and formation of liquid by-products were found to be dependent on the type of support. The H 2 selectivity showed the following trend: ZrO 2 > Al 2 O 3 ≈ CeO 2. The catalyst supported on CeO 2 showed low activity for water-gas shift reaction, with the highest CO selectivity. All catalysts presented a low formation of CH 4. In the liquid phase some by-products were identified (hydroxyacetone, acetic acid, lactic acid, acetaldehyde, acrolein and ethanol) and secondary reaction routes were proposed. Coke formation was higher on Ni/Al 2 O 3 catalyst, but no deactivation was observed during 8 h of reaction.
Yellow glycerol and crude glycerol, by-products of biodiesel, are renewable resource that can be used for sustainable production of hydrogen. The oxidative steam reforming of biodiesel by-products over Ni/CeO 2 -ZrO 2 /Al 2 O 3 catalyst were investigated and the effluents from reforming of both by-products were compared with that of pure glycerol. Preliminary analysis of yellow glycerol showed that there were methanol and fatty acid methyl esters in it whereas the presence of potassium (K) and sodium (Na) was observed in crude glycerol. The catalytic activity of Ni/CeO 2 -ZrO 2 /Al 2 O 3 catalyst was studied isothermally under atmospheric pressure at water-to-glycerol and oxygen-to-glycerol molar ratio of 9:1 and 0.5:1, respectively. Under these conditions, the glycerol was reformed to H 2 , CO 2 , CO and CH 4 with small amount of C 2 gas products that were measured by gas chromatograph. The results showed that the yellow glycerol was completely converted in gas phase and provided hydrogen yield and selectivity at 71% and 72%, respectively, whereas crude glycerol was nearly completed to convert in gas phase and gave the lowest hydrogen yield and selectivity at 37% and 42%, respectively because of the presence of coke formation. Therefore, the potential to produce hydrogen gas with low price feedstock like yellow glycerol was highly recommended with respect to pure glycerol.
Hydrogen production via glycerol dry reforming over La-Ni/Al 2O3 catalyst
2013
Glycerol (a bio-waste generated from biodiesel production) has been touted as a promising bio-syngas precursor via reforming route. Previous studies have indicated that carbon deposition is the major performance-limiting factor for nickel (Ni) catalyst during glycerol steam reforming. In the current paper, dry (CO2)-reforming of glycerol, a new reforming route was carried out over alumina (Al2O3)-supported nonpromoted and lanthanum-promoted Ni catalysts. Both sets of catalysts were synthesized via wet coimpregnation procedure. The physicochemical characterization of the catalyst showed that the promoted catalyst possessed smaller metal crystallite size, hence higher metal dispersion compared to the virgin Ni/Al2O3 catalyst. This was also corroborated by the surface images captured by the FESEM analysis. In addition, BET surface area measurement gave 92.05m²/g for non-promoted Ni catalyst whilst promoted catalysts showed an average of 1 to 6% improvement depending on the La loading. Reaction studies at 873 K showed that glycerol dry reforming successfully produced H2 with glycerol conversion and H2 yield that peaked at 9.7% and 25% respectively over 2wt% La content. The optimum catalytic performance by 2%La-Ni/Al2O3 can be attributed to the larger BET surface area and smaller crystallite size that ensured accessibility of active catalytic area.
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.
Bulletin of Chemical Reaction Engineering & Catalysis, 2016
The carbon dioxide (CO2) dry reforming of glycerol for syngas production is one of the promising ways to benefit the oversupply crisis of glycerol worldwide. It is an attractive process as it converts carbon dioxide, a greenhouse gas into a synthesis gas and simultaneously removed from the carbon biosphere cycle. In this study, the glycerol dry reforming was carried out using Silver (Ag) promoted Nickel (Ni) based catalysts supported on silicon oxide (SiO2) i.e. Ag-Ni/SiO2. The catalysts were prepared through wet impregnation method and characterized by using Brunauer-Emmett-Teller (BET) surface area, Scanning Electron Microscopy (SEM), X-ray Diffraction (XRD), and Thermo Gravimetric (TGA) analysis. The experiment was conducted in a tubular reactor which condition fixed at 973 K and CO2:glycerol molar ratio of 1, under atmospheric pressure. It was found that the main gaseous products are H₂, CO and CH4 with H₂:CO molar ratio < 1.0. From the reaction study, Ag(5)-Ni/SiO2 results i...
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%).
International Journal of Hydrogen Energy, 2013
H 2 production from glycerol steam reforming by the NieCueAl, NieCueMg, NieMg catalysts was evaluated experimentally in a continuous flow fixed-bed reactor under atmospheric pressure within a temperature range from 450 to 650 C. The catalysts were synthesized by the co-precipitation methods, and characterized by the elemental analysis, BET, XRD and SEM. The GC and FTIR were applied to analyze the products from steam reforming of glycerol. The coke deposited on the catalysts was measured by TGA experiments during medium temperature oxidation. The results showed that glycerol conversion and H 2 production were increased with increasing temperatures, and glycerol decomposition was favored over its steam reforming at low temperatures. The NieCueAl catalyst containing NiO of 29.2 wt%, CuO of 31.1 wt%, Al 2 O 3 of 39.7 wt% performed high catalytic activity, and the H 2 selectivity was found to be 92.9% and conversion of glycerol was up to 90.9% at 650 C. The deactivation of catalysts due to the formation and deposition of coke was observed. An improved iterative CoatseRedfern method was used to evaluate the nonisothermal kinetic parameters of coke removal from catalysts, and the results showed the reaction order of n ¼ 1 and 2 in the Fn nth order reaction model predicted accurately the main phase in the coke removal for the regeneration of NieMg and NieCueAl catalysts, respectively.
HYDROGEN GAS PRODUCTION FROM GLYCEROL VIA STEAM REFORMING USING NICKEL LOADED ZEOLITE CATALYST
Glycerol is the main by-product of biodiesel production that produces from transesterification process. In this research, focused was on hydrogen production via glycerol steam reforming using nickel loaded HZSM-5 catalyst. The catalysts were prepared by using different loading amount of nickel (0.5, 1.0, 5.0, 10.0 and 15 wt %) on HZSM-5 catalyst through the wet impregnation method at temperature 500 ºC and atmospheric pressure. The catalyst was characterized by using XRD, FTIR and SEM. Then, only 15 wt % Ni loading has been chosen based on the parameter which is different range of catalyst weight (0.3-0.5g) at different range of glycerol flow rate (0.2-0.4mL/min) at temperature 600 ºC and atmospheric pressure. The products were analyzed by using gas-chromatography with thermal conductivity detector (GC-TCD) where it is used to identify the yield of hydrogen. The data of the experiment were analyzed by using Response Surface Methodology (RSM) in order to study the relationship of catalyst weight and glycerol flow rate. The results showed that the optimum condition to produce a maximum hydrogen yield with 15wt% Ni/HZSM-5 catalyst was 78.10004% at glycerol flow rate of 0.356484 mL/min and catalyst weight of 0.429267 g.