Insights into coke location of catalyst deactivation during in-situ catalytic reforming of lignite pyrolysis volatiles over cobalt-modified zeolites

Dehalogenation of low-chlorinated arenes such as p-dichlorobenzene or chlorobenzene with the title hydride is accelerated in the presence of transition metal species formed in situ from the corresponding 2,4-pentanedionates. Their efficiency decreases in the order: Co ≈ Ni ≈ Pd > Cu >> Mn > Fe which results from changes of their activity and stability. The dehalogenation is well described by a kinetic model consisting of the set of dehalogenation steps which are first order in the chloroarene combined with the catalyst deactivation which is second order in the transition metal compound.

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IN SITU Device for Real-Time Catalyst Deactivation Measurements

10.2172/924163 ◽

2008 ◽

Author(s):

◽

Keyword(s):

Real Time ◽

Catalyst Deactivation

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Structural Insight into La0.5Ca0.5Mn0.5Co0.5O3 Decomposition in the Methane Combustion Process

Nanomaterials ◽

10.3390/nano11092283 ◽

2021 ◽

Vol 11 (9) ◽

pp. 2283

Author(s):

Olga Nikolaeva ◽

Aleksandr Kapishnikov ◽

Evgeny Gerasimov

Keyword(s):

Solid Solution ◽

Catalyst Deactivation ◽

Combustion Process ◽

Methane Combustion ◽

Large Loss ◽

In Situ Xrd ◽

Oxide Particles ◽

Structural Insight ◽

Insight Into

Perovskite-like solid solution La0.5Ca0.5Mn0.5Co0.5O3 was tested during the total methane combustion reaction. During the reaction, there is a noticeable decrease in methane conversion, the rate of catalyst deactivation increasing with an increase in temperature. The in situ XRD and HRTEM methods show that the observed deactivation occurs as a result of the segregation of calcite and cobalt oxide particles on the perovskite surface. According to the TGA, the observed drop in catalytic activity is also associated with a large loss of oxygen from the perovskite structure.

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Inductive Heating Assisted-Catalytic Dehydrogenation of Tetralin as a Hydrogen Source for Downhole Catalytic Upgrading of Heavy Oil

Topics in Catalysis ◽

10.1007/s11244-019-01206-w ◽

2019 ◽

Vol 63 (3-4) ◽

pp. 268-280 ◽

Cited By ~ 4

Author(s):

Abarasi Hart ◽

Mohamed Adam ◽

John P. Robinson ◽

Sean P. Rigby ◽

Joseph Wood

Keyword(s):

Catalyst Deactivation ◽

Oil Quality ◽

Coke Formation ◽

Coke Deposition ◽

Conventional Heating ◽

Inductive Heating ◽

Catalytic Dehydrogenation ◽

Catalytic Upgrading ◽

Bed Temperature

AbstractThe Toe-to-Heel Air Injection (THAI) combined with a catalytic add-on (CAPRI, CATalytic upgrading PRocess In-situ) have been a subject of investigation since 2002. The major challenges have been catalyst deactivation due to coke deposition and low temperatures (~ 300 °C) of the mobilised hot oil flowing over the catalyst packing around the horizontal well. Tetralin has been used to suppress coke formation and also improve upgraded oil quality due to its hydrogen-donor capability. Herein, inductive heating (IH) incorporated to the horizontal production well is investigated as one means to resolve the temperature shortfall. The effect of reaction temperature on tetralin dehydrogenation and hydrogen evolution over NiMo/Al2O3 catalyst at 250–350 °C, catalyst-to-steel ball ratio (70% v/v), 18 bar and 0.75 h−1 was investigated. As temperature increased from 250 to 350 °C, tetralin conversion increased from 40 to 88% while liberated hydrogen increased from 0.36 to 0.88 mol based on 0.61 mol of tetralin used. The evolved hydrogen in situ hydrogenated unreacted tetralin to trans and cis-decalins with the selectivity of cis-decalin slightly more at 250 °C while at 300–350 °C trans-decalin showed superior selectivity. With IH the catalyst bed temperature was closer to the desired temperature (300 °C) with a mean of 299.2 °C while conventional heating is 294.3 °C. This thermal advantage and the nonthermal effect from electromagnetic field under IH improved catalytic activity and reaction rate, though coke formation increased.

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Exploiting In-Situ Characterization for a Sabatier Reaction to Reveal Catalytic Details

Chemistry ◽

10.3390/chemistry3040084 ◽

2021 ◽

Vol 3 (4) ◽

pp. 1157-1165

Author(s):

Simon Yunes ◽

Urim Pearl Kim ◽

Hoang Nguyen ◽

Jeffrey Kenvin

Keyword(s):

High Temperature ◽

Active Sites ◽

Catalyst Deactivation ◽

Active Species ◽

Catalyst Characterization ◽

In Situ Characterization ◽

Spent Catalyst ◽

Sabatier Reaction

In situ characterization of catalysts provides important information on the catalyst and the understanding of its activity and selectivity for a specific reaction. TPX techniques for catalyst characterization reveal the role of the support on the stabilization and dispersion of the active sites. However, these can be altered at high temperature since sintering of active species can occur as well as possible carbon deposition through the Bosch reaction, which hinders the active species and deactivates the catalyst. In situ characterization of the spent catalyst, however, may expose the causes for catalyst deactivation. For example, a simple TPO analysis on the spent catalyst may produce CO and CO2 via a reaction with O2 at high temperature and this is a strong indication that deactivation may be due to the deposition of carbon during the Sabatier reaction. Other TPX techniques such as TPR and pulse chemisorption are also valuable techniques when they are applied in situ to the fresh catalyst and then to the catalyst upon deactivation.

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Bioalcohol Reforming: An Overview of the Recent Advances for the Enhancement of Catalyst Stability

Catalysts ◽

10.3390/catal10060665 ◽

2020 ◽

Vol 10 (6) ◽

pp. 665 ◽

Cited By ~ 3

Author(s):

Vincenzo Palma ◽

Concetta Ruocco ◽

Marta Cortese ◽

Marco Martino

Keyword(s):

Fossil Fuels ◽

Catalyst Deactivation ◽

Coke Formation ◽

Catalyst Stability ◽

Side Reactions ◽

Catalytic Reforming ◽

Aqueous Phase Reforming ◽

Production Of Hydrogen ◽

Interesting Approach ◽

Reforming Reactions

The growing demand for energy production highlights the shortage of traditional resources and the related environmental issues. The adoption of bioalcohols (i.e., alcohols produced from biomass or biological routes) is progressively becoming an interesting approach that is used to restrict the consumption of fossil fuels. Bioethanol, biomethanol, bioglycerol, and other bioalcohols (propanol and butanol) represent attractive feedstocks for catalytic reforming and production of hydrogen, which is considered the fuel of the future. Different processes are already available, including steam reforming, oxidative reforming, dry reforming, and aqueous-phase reforming. Achieving the desired hydrogen selectivity is one of the main challenges, due to the occurrence of side reactions that cause coke formation and catalyst deactivation. The aims of this review are related to the critical identification of the formation of carbon roots and the deactivation of catalysts in bioalcohol reforming reactions. Furthermore, attention is focused on the strategies used to improve the durability and stability of the catalysts, with particular attention paid to the innovative formulations developed over the last 5 years.

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Mathematical modeling and optimization of semi-regenerative catalytic reforming of naphtha

Oil & Gas Science and Technology – Revue d’IFP Energies nouvelles ◽

10.2516/ogst/2021041 ◽

2021 ◽

Vol 76 ◽

pp. 64

Author(s):

Emilia Ivanchina ◽

Ekaterina Chernyakova ◽

Inna Pchelintseva ◽

Dmitry Poluboyartsev

Keyword(s):

Octane Number ◽

Catalyst Deactivation ◽

Formation Rate ◽

Coke Formation ◽

Space Velocity ◽

Catalyst Stability ◽

Hydrocarbon Mixture ◽

Catalytic Reforming ◽

Modeling And Optimization ◽

Petroleum Refineries

Catalytic naphtha reforming is extensively applied in petroleum refineries and petrochemical industries to convert low-octane naphtha into high-octane gasoline. Besides, this process is an important source of hydrogen and aromatics obtained as side products. The bifunctional Pt-catalysts for reforming are deactivated by coke formation during an industrial operation. This results to a reduction in the yield and octane number. In this paper modeling and optimization of a semi-egenerative catalytic reforming of naphtha is carried out considering catalyst deactivation and a complex multicomponent composition of a hydrocarbon mixture. The mathematical model of semi-egenerative catalytic reforming considering coke formation process was proposed. The operating parameters (yield, octane number, activity) for different catalysts were predicted and optimized. It was found that a decrease in the pressure range from 1.5 to 1.2 MPa at the temperature 478–481 °C and feedstock space velocity equal to 1.4–1 h induces an increase in the yield for 1–2 wt.% due to an increase in the aromatization reactions rate and a decrease in the hydrocracking reactions rate depending on the feedstock composition and catalyst type. It is shown that the decrease in pressure is limited by the requirements for the catalyst stability due to the increase in the coke formation rate. The criterion of optimality is the yield, expressed in octanes per tons.

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