scholarly journals Honeycomb Structured Catalysts for H2 Production via H2S Oxidative Decomposition

Catalysts ◽  
2018 ◽  
Vol 8 (11) ◽  
pp. 488 ◽  
Author(s):  
Vincenzo Palma ◽  
Daniela Barba ◽  
Vincenzo Vaiano ◽  
Michele Colozzi ◽  
Emma Palo ◽  
...  
Keyword(s):  
Catalytic Performance ◽  
Dip Coating ◽  
H2 Production ◽  
Sem Analysis ◽  
Operating Conditions ◽  
Structured Catalysts ◽  
Structured Catalyst ◽  
Honeycomb Monolith ◽  
Different Temperatures ◽  
H2 Yield

Cordierite honeycomb structured catalysts were studied for the reaction of H2S decomposition in the presence of oxygen to obtain H2 and sulphur. An Al2O3-based washcoat was deposited on the honeycomb monolith by a dip-coating procedure. In particular, three different washcoat percentages (15, 20 and 30 wt%) were deposited on the structured carrier and the obtained samples were characterized by N2 adsorption and SEM analysis. The evaluation of the catalytic performance of the three samples was carried out at two different temperatures (1000 °C and 1100 °C). The sample with 30 wt% washcoat content showed the lowest SO2 selectivity at 1000 °C (<0.4%), whereas the H2S conversion and H2 yield values were very similar to those achieved for the samples at 15 and 20 wt% washcoat loading. Based on these results, additional tests were carried out on the catalyst with 30 wt% Al2O3-based washcoat loading, varying the contact time and the H2S inlet concentration to identify the operating conditions that minimize the SO2 formation, obtaining good H2S conversion and H2 yield. The comparison of the structured catalyst with the powder alumina sample has shown the same catalytic performance, exhibiting lower SO2 selectivity.

scholarly journals Nickel-Based Structured Catalysts for Indirect Internal Reforming of Methane

2020 ◽  
Vol 10 (9) ◽  
pp. 3083
Author(s):  
Mariarita Santoro ◽  
Igor Luisetto ◽  
Simonetta Tuti ◽  
Silvia Licoccia ◽  
Claudia Romano ◽  
...  
Keyword(s):  
Focused Ion Beam ◽  
Ion Beam ◽  
Operating Conditions ◽  
Dry Reforming Of Methane ◽  
Metallic Foam ◽  
X Ray ◽  
Structured Catalysts ◽  
Internal Reforming ◽  
Structured Catalyst ◽  
Coating Method

A structured catalyst for the dry reforming of methane (DRM) was investigated as a biogas pre-reformer for indirect internal reforming solid oxide fuel cell (IIR-SOFC). For this purpose, a NiCrAl open-cell foam was chosen as support and Ni-based samarium doped ceria (Ni-SmDC) as catalyst. Ni-SmDC powder is a highly performing catalyst showing a remarkable carbon resistance due to the presence of oxygen vacancies that promote coke gasification by CO2 activation. Ni-SmDC powder was deposited on the metallic support by wash-coating method. The metallic foam, the powder, and the structured catalyst were characterized by several techniques such as: N2 adsorption-desorption technique, X-ray diffraction (XRD), scanning electron microscopy with energy dispersive X-ray spectroscopy (SEM-EDX), focused ion beam (FIB), temperature programmed reduction (H2-TPR), and Raman spectroscopy. Catalytic tests were performed on structured catalysts to evaluate activity, selectivity, and stability at SOFC operating conditions.

scholarly journals Hydrotalcite-Type Materials Electrodeposited on Open-Cell Metallic Foams as Structured Catalysts

Inorganics ◽  
2018 ◽  
Vol 6 (3) ◽  
pp. 74 ◽  
Author(s):  
Phuoc Ho ◽  
Erika Scavetta ◽  
Domenica Tonelli ◽  
Giuseppe Fornasari ◽  
Angelo Vaccari ◽  
...  
Keyword(s):  
Catalytic Performance ◽  
H2 Production ◽  
High Specific Surface Area ◽  
Metallic Foams ◽  
Open Cell ◽  
Structured Catalysts ◽  
Fundamental Understanding ◽  
Acidic Sites ◽  
Coating Procedure

Structured catalysts based on hydrotalcite-derived coatings on open-cell metallic foams combine tailored basic/acidic sites, relatively high specific surface area and/or metal dispersion of the coating as well as low pressure drop and enhanced heat and mass transfer of the 3D metallic support. The properties of the resulting structured catalysts depend on the coating procedure. We have proposed the electro-base generation method for in situ and fast precipitation of Ni/Al and Rh/Mg/Al hydrotalcite-type materials on FeCrAlloy foams, which after calcination at high temperature give rise to structured catalysts for syngas (CO + H2) production through Steam Reforming and Catalytic Partial Oxidation of CH4. The fundamental understanding of the electrochemical-chemical reactions relevant for the electrodeposition and the influence of electrosynthesis parameters on the properties of the as-deposited coatings as well the resulting structured catalysts and, hence, on their catalytic performance, were summarized.

Modelling of the Membrane Permeability Effect on the H2 Production Using CFD Method

2014 ◽  
Vol 12 (1) ◽  
pp. 333-344 ◽  
Author(s):  
Yacine Benguerba ◽  
Christine Dumas ◽  
Barbara Ernst
Keyword(s):  
Three Dimensional ◽  
Porous Membrane ◽  
H2 Production ◽  
Operating Conditions ◽  
Membrane Reactors ◽  
Production Of Hydrogen ◽  
Different Temperatures ◽  
Computational Fluid Dynamics Cfd ◽  
Cfd Method ◽  
Supported Ni

Abstract Autothermal reforming of CH4 in a membrane catalytic microreactor for the production of hydrogen at different temperatures over supported Ni catalysts has been studied. A three-dimensional mathematical model was developed using a computational fluid dynamics (CFD) technique. The effect of using different membranes on the performance of the micro-reactor was analysed. The amounts of hydrogen produced and separated in each case, under the same operating conditions, were compared. It was proven that using the porous membrane (Ni–Al2O3) could be an economic solution for the production and separation of hydrogen in membrane reactors.

scholarly journals Catalytic Steam Reforming of Toluene: Understanding the Influence of the Main Reaction Parameters over a Reference Catalyst

Energies ◽  
2020 ◽  
Vol 13 (4) ◽  
pp. 813 ◽  
Author(s):  
Hua Lun Zhu ◽  
Laura Pastor-Pérez ◽  
Marcos Millan
Keyword(s):  
Steam Reforming ◽  
High Performance ◽  
Space Velocity ◽  
Catalytic Performance ◽  
H2 Production ◽  
Operating Conditions ◽  
Molar Ratio ◽  
Main Reaction ◽  
Toluene Conversion ◽  
Steam Reforming Of Toluene

Identifying the suitable reaction conditions is key to achieve high performance and economic efficiency in any catalytic process. In this study, the catalytic performance of a Ni/Al2O3 catalyst, a benchmark system—was investigated in steam reforming of toluene as a biomass gasification tar model compound to explore the effect of reforming temperature, steam to carbon (S/C) ratio and residence time on toluene conversion and gas products. An S/C molar ratio range from one to three and temperature range from 700 to 900 °C was selected according to thermodynamic equilibrium calculations, and gas hourly space velocity (GHSV) was varied from 30,600 to 122,400 h−1 based on previous work. The results suggest that 800 °C, GHSV 61,200 h−1 and S/C ratio 3 provide favourable operating conditions for steam reforming of toluene in order to get high toluene conversion and hydrogen productivity, achieving a toluene to gas conversion of 94% and H2 production of 13 mol/mol toluene.

scholarly journals Role of Mixed Oxides in Hydrogen Production through the Dry Reforming of Methane over Nickel Catalysts Supported on Modified γ-Al2O3

Processes ◽  
2021 ◽  
Vol 9 (1) ◽  
pp. 157
Author(s):  
Ahmed Sadeq Al-Fatesh ◽  
Mayankkumar Lakshmanbhai Chaudhary ◽  
Anis Hamza Fakeeha ◽  
Ahmed Aidid Ibrahim ◽  
Fahad Al-Mubaddel ◽  
...  
Keyword(s):  
Mixed Oxides ◽  
Nickel Catalysts ◽  
H2 Production ◽  
Dry Reforming ◽  
Dry Reforming Of Methane ◽  
Incipient Wetness Impregnation ◽  
Thermally Stable ◽  
Oxide Systems ◽  
Catalyst Systems ◽  
H2 Yield

H2 production through dry reforming of methane (DRM) is a hot topic amidst growing environmental and atom-economy concerns. Loading Ni-based reducible mixed oxide systems onto a thermally stable support is a reliable approach for obtaining catalysts of good dispersion and high stability. Herein, NiO was dispersed over MOx-modified-γ-Al2O3 (M = Ti, Mo, Si, or W; x = 2 or 3) through incipient wetness impregnation followed by calcination. The obtained catalyst systems were characterized by infrared, ultraviolet–visible, and X-ray photoelectron spectroscopies, and H2 temperature-programmed reduction. The mentioned synthetic procedure afforded the proper nucleation of different NiO-containing mixed oxides and/or interacting-NiO species. With different modifiers, the interaction of NiO with the γ-Al2O3 support was found to change, the Ni2+ environment was reformed exclusively, and the tendency of NiO species to undergo reduction was modified greatly. Catalyst systems 5Ni3MAl (M = Si, W) comprised a variety of species, whereby NiO interacted with the modifier and the support (e.g., NiSiO3, NiAl2O4, and NiWO3). These two catalyst systems displayed equal efficiency, >70% H2 yield at 800 °C, and were thermally stable for up to 420 min on stream. 5Ni3SiAl catalyst regained nearly all its activity during regeneration for up to two cycles.

scholarly journals Exergy analysis of a biomass-based multi-energy system

2019 ◽  
Vol 113 ◽  
pp. 02017
Author(s):  
Mariagiovanna Minutillo ◽  
Alessandra Perna ◽  
Alessandro Sorce
Keyword(s):  
Exergy Analysis ◽  
Energy System ◽  
H2 Production ◽  
Operating Conditions ◽  
Processing Unit ◽  
Storage Unit ◽  
Fuel Processing ◽  
Fuel Processor ◽  
Energy Processes ◽  
And Storage

This paper focuses on a biofuel-based Multi-Energy System generating electricity, heat and hydrogen. The proposed system, that is conceived as refit option for an existing anaerobic digester plant in which the biomass is converted to biogas, consists of: i) a fuel processing unit, ii) a power production unit based on the SOFC (Solid Oxide Fuel Cell) technology, iii) a hydrogen separation, compression and storage unit. The aim of this study is to define the operating conditions that allow optimizing the plant performances by applying the exergy analysis that is an appropriate technique to assess and rank the irreversibility sources in energy processes. Thus, the exergy analysis has been performed for both the overall plant and main plant components and the main contributors to the overall losses have been evaluated. Moreover, the first principle efficiency and the second principle efficiency have been estimated. Results have highlighted that the fuel processor (the Auto-Thermal Reforming reactor) is the main contributor to the global exergy destruction (9.74% of the input biogas exergy). In terms of overall system performance the plant has an exergetic efficiency of 53.1% (it is equal to 37.7% for the H2 production).

Influence of Impregnation-Vacuum Filtration Conditions on Ni Dispersion and Activity of Ni-Cordierite for Hydrogenation

2013 ◽  
Vol 781-784 ◽  
pp. 312-319
Author(s):  
Shao Wen Liu ◽  
Zhuo Long Guan ◽  
Lei Qing ◽  
Jiu Ling Chen ◽  
Hai Nan Wang ◽  
...  
Keyword(s):  
Solution Concentration ◽  
Catalytic Performance ◽  
Filtration Time ◽  
Filtration Method ◽  
Vacuum Filtration ◽  
Structured Catalysts ◽  
Preparation Conditions ◽  
Vacuum Degree ◽  
Close Relationship ◽  
Impregnation Time

The influence of the preparation conditions of the impregnation-vacuum filtration method was investigated systematically on the Ni dispersion and the activity of Ni-cordierite structured catalysts in hydrogenation of m-dinitrobenzene to m-phenylenediamine. H2-TPD measurement showed that the Ni dispersion has close relationship with the impregnation solution concentration of nickel nitrate, the impregnation time, the vacuum degree, the vacuum filtration time and the calcination temperature. The hydrogenation activity test and nitrogen physisorption investigation showed that the catalytic performance of Ni-cordierite is dependent upon the Ni dispersion and the chemisorption mode of m-dinitrobenzene on Ni particles.

Effect of Ions Substitution on Nanospace La-Fe-O Catalytic Properties for Simultaneous Removal of NOx and Soot

2013 ◽  
Vol 740 ◽  
pp. 565-569
Author(s):  
Xiao Xiao Meng ◽  
Mao Xiang Jing ◽  
Feng Lin He ◽  
Xiang Qian Shen
Keyword(s):  
High Performance ◽  
Catalytic Properties ◽  
Catalytic Performance ◽  
Dip Coating ◽  
Exhaust Emission ◽  
Simultaneous Removal ◽  
Microstructural Characteristics ◽  
Coating Method ◽  
Citrate Gel Process ◽  
Dip Coating Method

The catalysts La0.8K0.2FeO3(LKFO), La0.8K0.2Fe0.7Mn0.3O3(LKFMO) and La0.8K0.2Fe0.67Mn0.3Pt0.03O3(LKFMPO) were prepared by the citrate-gel process and the catalyst-coated honeycomb ceramic devices were prepared by the citrate-gel assisted dip-coating method. All the catalysts have a high performance on the simultaneous removal of NOxand soot at a temperature range of 200 to 400°C under the practical diesel exhaust emission. The obvious catalytic improvement is largely due to the effects of ions substitution, pore structure and microstructural characteristics of the catalysts. The catalytic performance order is LKFMPO > LKFMO > LKFO. Among them the LKFMPO catalyst shows the best catalytic properties, especially in the removal of NOx, with a maximum conversion rate of NOx(21.2%).

scholarly journals The Effect of Ni Addition onto a Cu-Based Ternary Support on the H2 Production over Glycerol Steam Reforming Reaction

Nanomaterials ◽  
2018 ◽  
Vol 8 (11) ◽  
pp. 931 ◽  
Author(s):  
Kyriaki Polychronopoulou ◽  
Nikolaos Charisiou ◽  
Kyriakos Papageridis ◽  
Victor Sebastian ◽  
Steven Hinder ◽  
...  
Keyword(s):  
Sol Gel ◽  
Strong Acid ◽  
H2 Production ◽  
Impregnation Method ◽  
Reaction Products ◽  
Cu Content ◽  
Ni Addition ◽  
Support Matrix ◽  
Temperature Programmed ◽  
H2 Yield

In the present study, Ni/Ce-Sm-xCu (x = 5, 7, 10 at.%) catalysts were prepared using microwave radiation coupled with sol-gel and followed by wetness impregnation method for the Ni incorporation. Highly dispersed nanocrystallites of CuO and NiO on the Ce-Sm-Cu support were found. Increase of Cu content seems to facilitate the reducibility of the catalyst according to the H2 temperature-programmed reduction (H2-TPR). All the catalysts had a variety of weak, medium and strong acid/basic sites that regulate the reaction products. All the catalysts had very high XC3H8O3 for the entire temperature (400–750 °C) range; from ≈84% at 400 °C to ≈94% at 750 °C. Ni/Ce-Sm-10Cu catalyst showed the lowest XC3H8O3-gas implying the Cu content has a detrimental effect on performance, especially between 450–650 °C. In terms of H2 selectivity (SH2) and H2 yield (YH2), both appeared to vary in the following order: Ni/Ce-Sm-10Cu > Ni/Ce-Sm-7Cu > Ni/Ce-Sm-5Cu, demonstrating the high impact of Cu content. Following stability tests, all the catalysts accumulated high amounts of carbon, following the order Ni/Ce-Sm-5Cu < Ni/Ce-Sm-7Cu < Ni/Ce-Sm-10Cu (52, 65 and 79 wt.%, respectively) based on the thermogravimetric analysis (TGA) studies. Raman studies showed that the incorporation of Cu in the support matrix controls the extent of carbon graphitization deposited during the reaction at hand.

scholarly journals CuZnAl-Oxide Nanopyramidal Mesoporous Materials for the Electrocatalytic CO2 Reduction to Syngas: Tuning of H2/CO Ratio

Nanomaterials ◽  
2021 ◽  
Vol 11 (11) ◽  
pp. 3052
Author(s):  
Hilmar Guzmán ◽  
Daniela Roldán ◽  
Adriano Sacco ◽  
Micaela Castellino ◽  
Marco Fontana ◽  
...  
Keyword(s):  
Noble Metals ◽  
Co2 Reduction ◽  
Reduction Process ◽  
Mesoporous Structure ◽  
Catalytic Performance ◽  
H2 Production ◽  
Ambient Conditions ◽  
Transfer Resistance ◽  
Faradaic Efficiency ◽  
Co2 Electroreduction

Inspired by the knowledge of the thermocatalytic CO2 reduction process, novel nanocrystalline CuZnAl-oxide based catalysts with pyramidal mesoporous structures are here proposed for the CO2 electrochemical reduction under ambient conditions. The XPS analyses revealed that the co-presence of ZnO and Al2O3 into the Cu-based catalyst stabilize the CuO crystalline structure and introduce basic sites on the ternary as-synthesized catalyst. In contrast, the as-prepared CuZn- and Cu-based materials contain a higher amount of superficial Cu0 and Cu1+ species. The CuZnAl-catalyst exhibited enhanced catalytic performance for the CO and H2 production, reaching a Faradaic efficiency (FE) towards syngas of almost 95% at −0.89 V vs. RHE and a remarkable current density of up to 90 mA cm−2 for the CO2 reduction at −2.4 V vs. RHE. The physico-chemical characterizations confirmed that the pyramidal mesoporous structure of this material, which is constituted by a high pore volume and small CuO crystals, plays a fundamental role in its low diffusional mass-transfer resistance. The CO-productivity on the CuZnAl-catalyst increased at more negative applied potentials, leading to the production of syngas with a tunable H2/CO ratio (from 2 to 7), depending on the applied potential. These results pave the way to substitute state-of-the-art noble metals (e.g., Ag, Au) with this abundant and cost-effective catalyst to produce syngas. Moreover, the post-reaction analyses demonstrated the stabilization of Cu2O species, avoiding its complete reduction to Cu0 under the CO2 electroreduction conditions.

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