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Basic characteristics of sulfide catalysts for the direct decomposition of H2S
Bonnet, Florian; Kaluža, Luděk
2024 - English
Sulfide catalysts are crucial in the hydrodesulfurization (HDS) of petroleum fractions, facilitating the hydrogenolysis of carbon-sulfur bonds. This process generates significant volumes of hydrogen sulfide (H2S), which is typically processed in the Claus unit. However, excess H2S can overwhelm the Claus process, creating both operational and environmental challenges. Researchers are now exploring sulfide catalysts for the direct thermo-catalytic decomposition of H2S to address this issue. Supported catalysts, like Mo/Al2O3, and commercial catalysts, considered typical monolayer-type well-dispersed catalysts, show the highest O2 uptake, ranging from 41.29 μmol/g for MoS2/Al2O3 (KLO) to 58.70 μmol/g for the commercial 715. Unsupported multilayer catalysts, such as Ni/MoWS2 (KKP), exhibit lower O2 uptake at 2.54 μmol/g, though it demonstrates high HDS activity with thiophene. Moreover, O2 uptake effectively describes the sintering of the Mo monolayer phase during the thermocatalytic reaction of H2S at 800°C. These O2 uptakes clearly correlate with the XRD patterns, where the MoS2 phase is X-ray amorphous with an O2 uptake of about 19.04 μmol/g, while the MoS2 phase in the spent catalyst shows certain crystallinity exhibiting an average particle size by Scherrer equation of about 6 nm and the O2 uptake of 1.63 μmol/g. O2 chemisorption thus serves as a valuable measure of the dispersion of Mo sulfides. The results obtain with the study of CoMo/Al2O3 (KJJ-family catalysts), highlight the correlation between the increasing amount of adsorbed O2 with the increasing nominal loading of MoO3 and the increasing rate constant of thiophene kTH. This research reveals the potential of these catalysts in hydrocarbon refining. The findings underline the connection between catalytic chemistry, process engineering, and environmental sustainability, with the objective to enhance industrial refining processes.
Keywords:
sulfide catalyst; O2 chemisorption; H2S decomposition
Available at various institutes of the ASCR
Basic characteristics of sulfide catalysts for the direct decomposition of H2S
Sulfide catalysts are crucial in the hydrodesulfurization (HDS) of petroleum fractions, facilitating the hydrogenolysis of carbon-sulfur bonds. This process generates significant volumes of hydrogen ...
EDWork Manual IV. User Guide to EDWork 4.1
Sobolík, Václav; Wein, Ondřej
2020 - English
The presen report would serve as a user guide to the software package EDWork 4.1.
Keywords:
electrodiffusion technique; edwork manual; user guide
Available at various institutes of the ASCR
EDWork Manual IV. User Guide to EDWork 4.1
The presen report would serve as a user guide to the software package EDWork 4.1.
Kinetic Study of a Gas Absorption Into a Liquid Stages 1.1 and 1.2
Stavárek, Petr
2018 - English
Report describes the experimental apparatus and measurements of the kinetics of a gas absorption into a liquid and reports the evaluated results.
Keywords:
experimental apparatus; measurements; gas absorption
Available at various institutes of the ASCR
Kinetic Study of a Gas Absorption Into a Liquid Stages 1.1 and 1.2
Report describes the experimental apparatus and measurements of the kinetics of a gas absorption into a liquid and reports the evaluated results.
39M-IMMEDIATE Research Report: Remarks on Repeatability Experiments and Perspective Exploitation of MAE Pt/C\nElectrocatalysts.
Kaluža, Luděk; Gulková, Daniela; Soukup, Karel
2016 - English
The 36-39 months of the projekt solution were devoted to summarize aspects of the most perspective results on Pt/C electrocatalysts preparation to focus on industrial expoitation. Chellenges of Pt dispersion in the Pt/C were compared with preliminary outcomes from volumetric determination of hydrogen adsorption.
Keywords:
Pt/c electrocatalysts; industrial exploitation; hydrogen absorption
Available at various institutes of the ASCR
39M-IMMEDIATE Research Report: Remarks on Repeatability Experiments and Perspective Exploitation of MAE Pt/C\nElectrocatalysts.
The 36-39 months of the projekt solution were devoted to summarize aspects of the most perspective results on Pt/C electrocatalysts preparation to focus on industrial expoitation. Chellenges of Pt ...
Hydrodynamic Study of the Downward Annular Gas-Liquid Flow under the Pilot Plant Operating Conditions 2013-2014.
Stavárek, Petr; Křišťál, Jiří
2014 - English
Hydrodynamics of annular liquid flow in a vertical tube with cocurrent gas flow has been studied. Effect of gas - liquid flow rate and liquid viscosity on two-phase flow hydrodynamics was investigated for glycerol – air system. The evaluated parameters were pressure drop and hydrodynamic regime at different gas/liquid ratios.
Keywords:
annular gas-liquid flow; pressure drop; hydrodynamics
Available at various institutes of the ASCR
Hydrodynamic Study of the Downward Annular Gas-Liquid Flow under the Pilot Plant Operating Conditions 2013-2014.
Hydrodynamics of annular liquid flow in a vertical tube with cocurrent gas flow has been studied. Effect of gas - liquid flow rate and liquid viscosity on two-phase flow hydrodynamics was investigated ...
18M-IMMEDIATE Research Report: Prototype of Catalyst Powder Sufficient for Testing in MEAs Fabricated
Kaluža, Luděk; Zdražil, Miroslav; Gulková, Daniela; Koštejn, Martin; Vít, Zdeněk
2014 - English
High loadings of platinum (60 wt%) were precipitated (ICPF) or depo-sited (CNRS) onto research grade carbon black supports provided by TC. The supports and the resulting electrocatalysts were thoroughly characterised in order to select the best ones for optimisation and up-scaled manufacturing. For the preparation and characterisation vari-ous methodologies have been developed. Batches of the gram size were prepared of a handful of the most promising catalysts. This is sufficient for the preparation of test MEAs.
Keywords:
Pt catalysts; stress tests; nitrogen physisorption
Available at various institutes of the ASCR
18M-IMMEDIATE Research Report: Prototype of Catalyst Powder Sufficient for Testing in MEAs Fabricated
High loadings of platinum (60 wt%) were precipitated (ICPF) or depo-sited (CNRS) onto research grade carbon black supports provided by TC. The supports and the resulting electrocatalysts were ...
Models of AWS Material Functions
Wein, Ondřej; Pěnkavová, Věra
2014 - English
New classes of 4-parameter models of fluidity for the shear-thinning non-Newtonian liquids are introduced, including their local pseudosimilarity representation. The models cover both purely-viscous (PV) and visco-plastic (VP) flow behavior. New 4-parameter model of slipidity (Navier slip coefficient) is introduced, as well as its modification for retarded AWS (slipidity decreasing with rising shear stress) and wall dilatancy (negative slipidity). Their asymptotic behavior, as well as their asymptotic sub-models are identified and prepared for implementation in the software AWSWork.
Keywords:
visco-plastic materials; purely viscous liquids; pseudosimilarity; material functions
Available on request at various institutes of the ASCR
Models of AWS Material Functions
New classes of 4-parameter models of fluidity for the shear-thinning non-Newtonian liquids are introduced, including their local pseudosimilarity representation. The models cover both purely-viscous ...
12M-IMMEDIATE Research Report: Preparation of Pt on Carbon Black Supported Catalysts
Kaluža, Luděk; Zdražil, Miroslav; Gulková, Daniela; Vít, Zdeněk; Šolcová, Olga; Soukup, Karel; Maixnerová, Lucie
2014 - English
The aim of this work was to elucidate on advanced preparation of Pt/C catalysts from TimCal carbon black and H2PtCl6. The attention was directed to residual content of chloride in the prepared catalysts and scale-up to the amount about 1 gram of final product. The textrual properties of the supports and selected catalyst were studied by nitrogen physisorption. The analytical methods such as instrumental neutron activation analysis (INAA), liquid ion chromatography (LC), and titration with silver nitrates were applied for Cl analysis. Electron probe micro analysis (SEM-EDX), hydrogen chemisorption, temperature programed desorption of hydrogen (TPD) and a simplified determination of ignition temperature in air flow were used for Pt/C catalysts characterization.
Keywords:
Pt/C catalysts; carbon black; analytical methods
Available at various institutes of the ASCR
12M-IMMEDIATE Research Report: Preparation of Pt on Carbon Black Supported Catalysts
The aim of this work was to elucidate on advanced preparation of Pt/C catalysts from TimCal carbon black and H2PtCl6. The attention was directed to residual content of chloride in the prepared ...
Rheology of Colloidal Dispersions: Deflocculation of Kaolin Dispersions
Guerreiro, M.I.A.; Růžička, Marek; Pěnkavová, Věra
2013 - English
All inorganic additives in their optimal concentrations proved to be effective at reducing the initial viscosity to 1%. In the case of NaOH two different trends were observed: firstly this additive behaved as a deflocculant agent where, at its optimal range of concentrations, the viscosity of kaolin dispersion reduced to its minimal value, secondly when used at concentrations above its optimal range, sodium hydroxide behaved like a flocculant agent increasing strongly the viscosity of kaolin dispersions. The possible cause was attributed to an excess of Na+ and OH- species in bulk media that promoted the reversible effect. Similar effect was also reported for NaCMC at high and medium molar weight, were the viscosity firstly decreased to a certain concentration of additive and then above that concentration started to increase. Thus low molar weight NaCMC was the most effective among the organic additives since it decreased the viscosity to 10% of initial viscosity. Qualitative evaluation showed that organic additives promoted more stable dispersions, in contrast to poor stability offered by the inorganic additives, with exception of NaOH that provided dispersions with good stability inside of its optimal range.
Keywords:
kaolin dispersions; yield strss; viscoplastic fluids
Available at various institutes of the ASCR
Rheology of Colloidal Dispersions: Deflocculation of Kaolin Dispersions
All inorganic additives in their optimal concentrations proved to be effective at reducing the initial viscosity to 1%. In the case of NaOH two different trends were observed: firstly this additive ...
6M-IMMEDIATE Research Report: Preparation of Pt on Carbon Black Supported Catalysts
Kaluža, Luděk; Zdražil, Miroslav; Gulková, Daniela; Vít, Zdeněk; Šolcová, Olga; Soukup, Karel; Maixnerová, Lucie
2013 - English
The purpose of the present work is to elucidate on carbon black materials as a support for high loading of Pt in highly dispersed form. There are three main methodologies described in the .literature for deposition of Pt: i) impregnation of the support with solution of well soluble Pt precursors, ii) deposition of a colloidal form of Pt onto the support, and iii) deposition of Pt onto the supports from microemulsion of Pt precursor with the assistance of surfactant. The Pt containing species are deposited either by spontaneous adsorption or by evaporation of the solvent. The deposited platinum compound is transformed to metallic platinum with some chemical or physical (temperature) treatment. Remainders of the deposited compound other than platinum must be removed from the catalysts (for instance by washing, calcination, etc.).
Keywords:
elucidate; carbon black materials; platinum
Available at various institutes of the ASCR
6M-IMMEDIATE Research Report: Preparation of Pt on Carbon Black Supported Catalysts
The purpose of the present work is to elucidate on carbon black materials as a support for high loading of Pt in highly dispersed form. There are three main methodologies described in the .literature ...
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