Coke formation in copper catalyst during cyclohexanol dehydrogenation: Kinetic deactivation model and catalyst characterization

2013 ◽  
Vol 214 ◽  
pp. 119-128 ◽  
Author(s):  
Ernesto Simón ◽  
Juana Maria Rosas ◽  
Aurora Santos ◽  
Arturo Romero
Keyword(s):  
Copper Catalyst ◽  
Coke Formation ◽  
Catalyst Characterization ◽  
Deactivation Model ◽  
Cyclohexanol Dehydrogenation

Hydrogen Production Using Autothermal Reforming of Biodiesel and Other Hydrocarbons for Fuel Cell Applications

Solar Energy ◽  
2006 ◽  
Author(s):  
Jose´ A. Colucci
Keyword(s):  
Gas Chromatography ◽  
Chemical Engineering ◽  
Flow Reactor ◽  
National Laboratory ◽  
Coke Formation ◽  
Plug Flow ◽  
Argonne National Laboratory ◽  
Future Research ◽  
Catalyst Characterization ◽  
Reactor Temperature

The department of Chemical Engineering of the University of Puerto Rico (UPRM) in collaboration with Argonne National Laboratory (ANL) works in the development of a reforming catalyst characterization program. The purpose of this research is to study the viability of using new catalysts to convert Biodiesel, Glycerin and Methanol to a hydrogen rich product gas and compare their production potential, identify the conditions for the accumulation of coke and determine the influence of reactor temperature and water to carbon and oxygen to carbon ratios. A Basket Stirred Tank Reactor (BSTR), Plug Flow Reactor (PFR), Gas Chromatography Mass Spectrophotometer (GCMS) and Gas Chromatography Thermal Conductivity Detector (GCTCD), and Pt and Rh-based catalysts synthesized at ANL were used. During the preliminary ATR experiments, methanol, glycerol and biodiesel showed an increase in H2 production with decreasing O2/C ratio and increases in the reactor temperature. Additionally, Scanning Electron Microscopy (SEM) and EDAX analysis has been performed in some of the catalysts samples. All biodiesel and glycerol experiments performed had shown coke formation. Future research will include, experiments with bio-ethanol and methane as fuel using a Ni-based catalyst synthesized at ANL.

Coke Formation on Zeolites Y and Their Deactivation Model

2020 ◽  
Vol 60 (4) ◽  
pp. 532-539
Author(s):  
M. V. Bukhtiyarova ◽  
G. V. Echevskii
Keyword(s):  
Coke Formation ◽  
Deactivation Model

The influence of zinc ions discharged in a non-aqueous cell on a copper catalyst on the rate of cyclohexanol dehydrogenation reaction

1996 ◽  
Vol 37 (1-2) ◽  
pp. 89-94 ◽  
Author(s):  
Andrzej Stokiosa ◽  
Janusz ZajÇcki ◽  
Grzegorz Wilczyński ◽  
Anna Wójtowicz ◽  
Stefan S. Kurek
Keyword(s):  
Copper Catalyst ◽  
Zinc Ions ◽  
Dehydrogenation Reaction ◽  
Cyclohexanol Dehydrogenation

scholarly journals Numerical Simulation and Experimental Study on Commercial Diesel Reforming Over an Advanced Pt/Rh Three-Way Catalyst

Catalysts ◽  
2019 ◽  
Vol 9 (7) ◽  
pp. 590 ◽  
Author(s):  
Hanyu Chen ◽  
Xi Wang ◽  
Zhixiang Pan ◽  
Hongming Xu
Keyword(s):  
Coke Formation ◽  
Chemical Properties ◽  
Hydrocarbon Fuel ◽  
Catalyst Characterization ◽  
Stoichiometric Ratio ◽  
Fuel Reforming ◽  
Reduced Mechanism ◽  
Composition Variation ◽  
The Difference ◽  
Physical And Chemical

Hydrocarbon fuel reforming has been proven useful for producing hydrogen that is utilized on road vehicles, but it is associated with reaction mechanism and catalyst characterization. In this study, a reduced mechanism for n-heptane/toluene reforming over an advanced Pt/Rh TWC is adopted to investigate the effects of the reaction conditions on H2 and CO concentrations. The physical and chemical properties of the advanced catalyst are examined using SEM, XRD and XPS analyses. The contrasted experiments are conducted to study the composition variation tendency of the reforming reactor gas product. The results show that the POX reaction is most likely to occur considering the stoichiometric ratio of H2/CO, and other reactions are SR or ATR. The coke formation and carbon deposition occur on the catalyst surface, and the diffraction peaks corresponding to the metallic Pt are observed, while no obvious peaks characteristic of Rh are detected. The characteristics of the concentration trend of n-heptane/toluene reforming can represent H2 and CO yield features of diesel reforming in a way; nevertheless, the difference of the average H2 and CO concentration is remarkable.

Investigation of Suitable Pretreatment for Dry Reforming of Methane Over Ni/Al2O3

2011 ◽  
Vol 233-235 ◽  
pp. 1665-1673 ◽  
Author(s):  
Ahmed Alfatesh ◽  
Anis Fakeeha
Keyword(s):  
Atmospheric Pressure ◽  
Catalyst Activity ◽  
Coke Formation ◽  
Tubular Reactor ◽  
Dry Reforming ◽  
Hydrogen Gas ◽  
Dry Reforming Of Methane ◽  
Experimental Result ◽  
Catalyst Characterization ◽  
Reforming Catalysts

Carbon dioxide reforming of methane to synthesis gas over an alumina-supported 1% Ni-based catalyst was investigated at atmospheric pressure. The effects of activation and calcination temperatures and the addition of calcium promoted on dry reforming catalysts supported on low surface area alumina Ni/α-Al2O3 (SA-5239) were studied experimentally. In this study, the prepared catalyst was tested in a micro tubular reactor at temperature ranges of 500, 600, 700 and 800°C, atmospheric pressure, using a total flow rate of 33 ml/min. of feed gas 3 ml/min of N2, 15 ml/min of CO2 and 15 ml/min of CH4. The calcination was carried out in the range of 500-900°C. The catalysts were activated inside the reactor at 500-800°C using hydrogen gas. It was observed that calcination enhances catalyst activity which increases as calcination and reaction temperatures were increased. It was found essential activating reforming catalysts with H2.The highest process activity was obtained at 800°C reaction temperature by using catalyst calcined and activated at 900°C and 700°C respectively. The addition of Ca promoter decreases the coke formation on catalyst, however, It initially reduces the activity. The catalyst characterization conducted supported the observed experimental result

Quantitative nano-characterization of heterogeneous catalysts

1995 ◽  
Vol 53 ◽  
pp. 398-399
Author(s):  
P.A. Crozier ◽  
M. Pan
Keyword(s):  
Heterogeneous Catalysts ◽  
Low Dose ◽  
Imaging Techniques ◽  
Structural Features ◽  
Catalyst Characterization ◽  
New Developments ◽  
Double Phase ◽  
Phase Systems ◽  
Dose Imaging

Heterogeneous catalysts can be of varying complexity ranging from single or double phase systems to complicated mixtures of metals and oxides with additives to help promote chemical reactions, extend the life of the catalysts, prevent poisoning etc. Although catalysis occurs on the surface of most systems, detailed descriptions of the microstructure and chemistry of catalysts can be helpful for developing an understanding of the mechanism by which a catalyst facilitates a reaction. Recent years have seen continued development and improvement of various TEM, STEM and AEM techniques for yielding information on the structure and chemistry of catalysts on the nanometer scale. Here we review some quantitative approaches to catalyst characterization that have resulted from new developments in instrumentation.HREM has been used to examine structural features of catalysts often by employing profile imaging techniques to study atomic details on the surface. Digital recording techniques employing slow-scan CCD cameras have facilitated the use of low-dose imaging in zeolite structure analysis and electron crystallography. Fig. la shows a low-dose image from SSZ-33 zeolite revealing the presence of a stacking fault.

An analytical microscopic study of metals in fluidized catalytic cracking catalyst

1986 ◽  
Vol 44 ◽  
pp. 854-855
Author(s):  
Clifford S. Rainey
Keyword(s):  
Electron Microscopy ◽  
Spatial Distribution ◽  
Catalytic Cracking ◽  
Catalyst Deactivation ◽  
Coke Formation ◽  
Acid Sites ◽  
Y Zeolite ◽  
Fcc Catalyst ◽  
Fluidized Catalytic Cracking ◽  
High Regeneration

The spatial distribution of V and Ni deposited within fluidized catalytic cracking (FCC) catalyst is studied because these metals contribute to catalyst deactivation. Y zeolite in FCC microspheres are high SiO2 aluminosilicates with molecular-sized channels that contain a mixture of lanthanoids. They must withstand high regeneration temperatures and retain acid sites needed for cracking of hydrocarbons, a process essential for efficient gasoline production. Zeolite in combination with V to form vanadates, or less diffusion in the channels due to coke formation, may deactivate catalyst. Other factors such as metal "skins", microsphere sintering, and attrition may also be involved. SEM of FCC fracture surfaces, AEM of Y zeolite, and electron microscopy of this work are developed to better understand and minimize catalyst deactivation.

Elemental Distribution in Pt-Re:Al2O3 Naphtha Reforming Catalysts

1980 ◽  
Vol 38 ◽  
pp. 200-201
Author(s):  
R. L. Freed ◽  
M. J. Kelley
Keyword(s):  
Bimetallic Catalyst ◽  
Supported Catalysts ◽  
Coke Formation ◽  
Materials Characterization ◽  
Metal Catalyst ◽  
Elemental Distribution ◽  
Exact Nature ◽  
Naphtha Reforming ◽  
Reforming Catalysts ◽  
Commercial Introduction

The commercial introduction of Pt-Re supported catalysts to replace Pt alone on Al2O3 has brought improvements to naphtha reforming. The bimetallic catalyst can be operated continuously under conditions which lead to deactivation of the single metal catalyst by coke formation. Much disagreement still exists as to the exact nature of the bimetallic catalyst at a microscopic level and how it functions in the process so successfully. The overall purpose of this study was to develop the materials characterization tools necessary to study supported catalysts. Specifically with the Pt-Re:Al2O3 catalyst, we sought to elucidate the elemental distribution on the catalyst.

Coke formation on HFAU and HEMT zeolites. Influence of the reaction temperature and propene pressure

1999 ◽  
Vol 96 (2) ◽  
pp. 303-318 ◽  
Author(s):  
G. A. Doka Nassionou ◽  
P. Magnoux ◽  
M. Guisnet
Keyword(s):  
Reaction Temperature ◽  
Coke Formation

Life Time Improvement of Hierarchically Structured SAPO-34 Nanocatalyst in MTO Reaction via Applying Clinoptilolite, Investigating of Composite Design via RSM

2020 ◽  
Vol 23 ◽  
Author(s):  
Reza Yazdanpanah ◽  
Eshagh Moradiyan ◽  
Rouein Halladj ◽  
Sima Askari
Keyword(s):  
Surface Area ◽  
Natural Zeolite ◽  
Coke Formation ◽  
Life Time ◽  
Weight Percent ◽  
Light Olefins ◽  
Bet Surface Area ◽  
Relative Crystallinity ◽  
Mto Reaction ◽  
The Common

Aim and Objective: The research focuses on recent progress in the production of light olefins. Hence, the common catalyst of the reaction (SAPO-34) deactivates quickly because of coke formation, we reorganized the mechanism combining SAPO-34 with a natural zeolite in order to delay the deactivation time. Materials and Methods: The synthesis of nanocomposite catalyst was conducted hydrothermally using experimental design. Firstly, Clinoptilolite was modified using nitric acid in order to achieve nano scaled material. Then, the initial gel of the SAPO-34 was prepared using DEA, aluminum isopropoxide, phosphoric acid and TEOS as the organic template, sources of Aluminum, Phosphor, and Silicate, respectively. Finally, the modified zeolite was combined with SAPO-34's gel. Results: 20 different catalysts due to D-Optimal design were synthesized and the nanocomposite with 50 weight percent of SAPO-34, 4 hours Crystallization and early Clinoptilolite precipitation showed the highest relative crystallinity, partly high BET surface area and hierarchical structure. Conclusion: Different analysis illustrated the existence of both components. The most important property alteration of nanocomposite was the increment of pore mean diameters and reduction in pore volumes in comparison with free SAPO-34. Due to low price of Clinoptilolite, the new catalyst develops the economy of the process. Using this composite, according to formation of multi-sized pores located hierarchically on the surface of the catalyst and increased surface area, significant amounts of Ethylene and Propylene, in comparison with free SAPO-34, were produced, as well as deactivation time that was improved.

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