Dry Reforming Of Ethanol Research Articles

Thermodynamic analysis and process simulation for the H2 production by dry reforming of ethanol with CaCO3

The dry reforming of hydrocarbons, which employs CO2 to produce hydrogen–synthesis gas (H2-syngas) and the use of ethanol as a renewable feedstock is a convenient process that would prevent CO2 emissions into the atmosphere. One innovative approach is the use of a solid carbonate to serve as a source of CO2 for this process. Decomposition of a solid carbonate at high temperatures, will emit CO2, which is then can be used as a raw material along with ethanol (EtOH) to produce H2-syngas. The present work is aimed to perform a thermodynamic analysis and process simulation to explore reaction conditions close to equilibrium for a high H2-syngas production, under the dry reforming of ethanol. CaCO3 was used as CO2 source for the reaction system. Results indicate that at T ≥ 750 °C and CaCO3/EtOH ≥ 2.2, a free carbon formation syngas can be produced. Maximum H2 was obtained at 790 °C.

Hydrogen production by conversion of ethanol using atmospheric pressure microwave plasmas

The efficiency of hydrogen production from ethanol in the atmospheric pressure plasma generated in waveguide-supplied metal-cylinder-based microwave plasma source (MPS) was investigated experimentally. The tested parameters of hydrogen production efficiency were: hydrogen production rate in NL(H2)/h, energy yield of hydrogen production in NL(H2)/kWh, ethanol conversion degree in % and volume concentration of hydrogen in the outlet gas in %. Two ethanol based methods of hydrogen production were performed, namely ethanol dry and steam reforming. The best achieved experimental results showed that the energy yield of hydrogen production was about 78 NL(H2) per kWh of absorbed microwave energy in the case of ethanol dry reforming and about 257 NL(H2)/kWh in the case of ethanol steam reforming. Presented microwave plasma method can be successfully used for hydrogen production not only from ethanol, but also from different liquid compounds like gasoline, heavy oils and biofuels.

Study of the dry reforming of methane and ethanol using Rh catalysts supported on doped alumina

Various MxOy–Al2O3 oxides (M=Zr, Mg, Ni, Ce, La), prepared by a sol–gel method, were used as supports for rhodium catalysts in methane and ethanol dry reforming. After calcination, the Rh/MxOy–Al2O3 catalysts present BET surface areas between 85 and 208m2g−1. For the CH4 dry reforming, the highest yields in hydrogen are obtained in the following ranking: Rh/NiO–Al2O3>Rh/Al2O3>Rh/MgO–Al2O3≈Rh/CeO2–Al2O3>Rh/ZrO2–Al2O3>Rh/La2O3–Al2O3, not very different from the one for ethanol dry reforming at 800°C which is: Rh/NiO–Al2O3≫Rh/Al2O3≈Rh/MgO–Al2O3≈Rh/CeO2–Al2O3>Rh/ZrO2–Al2O3≈Rh/La2O3–Al2O3, although the reaction temperature is different. For the two reactions, the best catalyst is Rh/NiO–Al2O3 even if it deactivates during the reaction due to carbon deposition. This high activity may be explained by both the presence of the NiAl2O4 spinel phase, avoiding the deactivation of rhodium by migration in alumina, and the high dispersion of Rh favored by the presence of nickel particles at the support surface. Moreover, Ni particles on the support surface also contribute to the activity as demonstrated by the high hydrogen yield obtained in the presence of NiO–Al2O3, which is similar to the one obtained with Rh/Al2O3.

Dry reforming of ethanol over supported Ni catalysts prepared by impregnation with methanolic solution

Nickel catalysts were prepared on single-oxide supports of Al2O3, CeO2, MgO and ZrO2 by impregnation of the oxide with a solution of Ni(NO3)2 in methanol. The catalysts were characterized by N2 physisorption (BET method), TPR, XRD, SEM and Raman spectroscopy and tested in dry reforming of ethanol (DRE). It was observed that the interaction with the support and Ni reducibility depended on the support used. According to TPR results, NiO species supported on CeO2 and Al2O3 were the easiest to reduce. Possibly, this behavior combined to redox properties of CeO2 inhibited side undesirable reactions and contributed to the higher selectivity for H2 on the NiCe catalyst. The catalytic test at 750°C on NiCe showed better H2 selectivity than the test at 700°C, suggesting that the higher temperature enhanced CO2 conversion and hindered carbon deposition in dry reforming of ethanol reactions.

Microkinetic modeling and analysis of ethanol partial oxidation and reforming reaction pathways on platinum at short contact times

In this work, a novel microkinetic model for ethanol partial oxidation and reforming on platinum (Pt) is developed and validated with minimal parameter tuning against experimental data at short contact times. Mechanistic analysis of the surface chemistry indicates the presence of up to four reaction zones over the length of the catalyst, viz., (i) ethanol dehydration and oxidation, (ii) transition from ethanol oxidation to dry reforming, (iii) dry reforming of ethanol, and (iv) dry and steam reforming of methane. As the majority of the catalyst is dominated by dry reforming conditions, additional validation of the microkinetic model is carried out with methane dry reforming experiments on Pt/Al2O3. The proposed microkinetic model for ethanol partial oxidation and reforming is able to predict the dry reforming data without further adjustment of kinetic parameters.

Steam and CO2 reforming of ethanol over Rh/CeO2 catalyst

The performance of ceria supported Rh catalysts prepared with high and low surface areas for steam reforming and dry reforming of ethanol was investigated. According to results of diffuse reflectance infrared Fourier transform spectroscopy of both reactions, dissociative adsorption of ethanol over ceria gives rise to ethoxy species and bridging OH groups. Oxidation of ethoxy species proceeds by addition of O provided by the support from species such as Type II bridging OH groups (i.e., steam reforming) or O adatoms (e.g., CO2 reforming). Rh promotes demethanation of acetate to carbonate and the steam/dry reforming of CHx species.Catalyst deactivation occurs from the deposition of carbon on the catalysts during both reactions. However, no carbon formation is observed on the Rh/CeO2 high surface area catalyst during steam reforming due to a higher surface fugacity of O from species adsorbed on the support that react to remove carbon.

Carbon dioxide reforming of ethanol over Ni/Y2O3–ZrO2 catalysts

Supported nickel catalysts of composition Ni/Y2O3–ZrO2 were synthesized in one step by the polymerization method and compared with a nickel catalyst prepared by wet impregnation. Stronger interactions were observed in the formed catalysts between NiO species and the oxygen vacancies of the Y2O3–ZrO2 in the catalysts made by polymerization, and these were attributed to less agglomeration of the NiO during the synthesis of the catalysts in one step. The dry reforming of ethanol was catalyzed with a maximum CO2 conversion of 61% on the 5NiYZ catalyst at 800°C, representing a better response than for the catalyst of the same composition prepared by wet impregnation.

Catalytic properties of carbon nano-filaments produced by iron-catalysed reforming of ethanol

Various applications for carbon nano-filaments (CNF), such as polymer additives, gas storage materials and catalyst supports have recently been reported. The present work focuses on the catalytic properties of carbon nano-filaments, as produced through the catalytic dry reforming of ethanol, using low-carbon steel as the catalyst. It has been quantitatively demonstrated that these carbon nano-filaments have high catalytic activity in respect of the ethanol dry reforming and cracking reactions. Iron carbide particles, encapsulated in the CNF, are shown to be the active agents possessing the observed catalytic properties. The exact reaction mechanism of this process is still unknown.