Study of coke deposition phenomena on the SAPO_34 catalyst and its effects on light olefin selectivity during the methanol to olefin reaction

RSC Advances ◽  
2015 ◽  
Vol 5 (100) ◽  
pp. 81965-81980 ◽  
Author(s):  
Reza Bagherian Rostami ◽  
Mohammad Ghavipour ◽  
Zuoxing Di ◽  
Yao Wang ◽  
Reza Mosayyebi Behbahani
Keyword(s):  
Hydrogen Transfer ◽  
Catalyst Deactivation ◽  
Coke Formation ◽  
Great Influence ◽  
Product Distribution ◽  
Coke Deposition ◽  
Light Olefin ◽  
Methanol To Olefin ◽  
Olefin Selectivity ◽  
Transfer Index

Hydrogen transfer index was found to be a key parameter in prediction of coke deposition behavior. A good macro-model of product distribution with coke formation is provided. Temperature had a great influence on distribution of coke species and catalyst deactivation.

CTAB-assisted size controlled synthesis of SAPO-34 and its contribution toward MTO performance

2018 ◽  
Vol 47 (29) ◽  
pp. 9861-9870 ◽  
Author(s):  
Syed ul Hasnain Bakhtiar ◽  
Xiaotong Wang ◽  
Sher Ali ◽  
Fulong Yuan ◽  
Zhibin Li ◽  
...  
Keyword(s):  
Controlled Synthesis ◽  
Pore System ◽  
Light Olefin ◽  
Diffusion Limitations ◽  
Small Pore ◽  
Methanol To Olefin ◽  
Olefin Selectivity ◽  
Size Controlled

SAPO-34 shows higher light olefin selectivity in the reaction of methanol to olefin (MTO), but its small pore system implies diffusion limitations to bigger molecular products and results in coking too.

Optimization of Vapor Phase Pyridine Synthesis Hindered by Rapid Catalyst Deactivation

2008 ◽  
Vol 6 (1) ◽  
Author(s):  
Suresh Kumar Reddy Kuppi Reddy ◽  
Inkollu Sreedhar ◽  
Kondapuram Vijaya Raghavan ◽  
Shivanand Janardan Kulkarni ◽  
Machiraju Ramakrishna
Keyword(s):  
Catalyst Deactivation ◽  
A Priori ◽  
Coke Formation ◽  
Product Distribution ◽  
Combined Effects ◽  
Reactor Operation ◽  
Proper Selection ◽  
Pyridine Bases ◽  
Deactivation Process ◽  
Selection Of

The synthesis of pyridine bases from acetaldehyde, formaldehyde and ammonia through aminocyclization continues to provide the best prospect for meeting growing demand. A proper selection of catalyst and standardization of process parameters are vital to achieve a market friendly product distribution and reactor operation. In this work, the major responsible factors for enhancing the activity and selectivity of HZS-5 catalysts have been identified and their individual and combined effects on aldehyde conversion, coke formation and selectivity to pyridine formation have been assessed. A priori assessment of catalyst time on stream behavior has been achieved by modeling the catalyst deactivation process.

scholarly journals Mechanistic Insights into Hydrodeoxygenation of Acetone over Mo/HZSM-5 Bifunctional Catalyst for the Production of Hydrocarbons

Energies ◽  
2021 ◽  
Vol 15 (1) ◽  
pp. 53
Author(s):  
Kai Miao ◽  
Tan Li ◽  
Jing Su ◽  
Cong Wang ◽  
Kaige Wang
Keyword(s):  
Hydrogen Pressure ◽  
Catalyst Deactivation ◽  
Catalyst Activity ◽  
Coke Formation ◽  
Bifunctional Catalyst ◽  
Acid Sites ◽  
Coke Deposition ◽  
Enhanced Production ◽  
Bio Oil ◽  
Catalytic Hydropyrolysis

Catalytic hydropyrolysis via the introduction of external hydrogen into catalytic pyrolysis process using hydrodeoxygenation catalysts is one of the major approaches of bio-oil upgrading. In this study, hydrodeoxygenation of acetone over Mo/HZSM-5 and HZSM-5 were investigated with focus on the influence of hydrogen pressure and catalyst deactivation. It is found that doped MoO3 could prolong the catalyst activity due to the suppression of coke formation. The influence of hydrogen pressure on catalytic HDO of acetone was further studied. Hydrogen pressure of 30 bar effectively prolonged catalyst activity while decreased the coke deposition over catalyst. The coke formation over the HZSM-5 and Mo/HZSM-5 under 30 bar hydrogen pressure decreased 66% and 83%, respectively, compared to that under atmospheric hydrogen pressure. Compared to the test with the HZSM-5, 35% higher yield of aliphatics and 60% lower coke were obtained from the Mo/HZSM-5 under 30 bar hydrogen pressure. Characterization of the spent Mo/HZSM-5 catalyst revealed the deactivation was mainly due to the carbon deposition blocking the micropores and Bronsted acid sites. Mo/HZSM-5 was proved to be potentially enhanced production of hydrocarbons.

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

2019 ◽  
Vol 63 (3-4) ◽  
pp. 268-280 ◽  
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.

Kinetic Modelling of Propane Dehydrogenation over a Pt–Sn/hierarchical SAPO-34 Zeolite Catalyst, Including Catalyst Deactivation

2017 ◽  
Vol 42 (4) ◽  
pp. 344-360
Author(s):  
Milad Komasi ◽  
Shohreh Fatemi ◽  
Seyed Hesam Mousavi
Keyword(s):  
Catalyst Deactivation ◽  
Kinetic Modelling ◽  
Coke Formation ◽  
Fixed Bed ◽  
Reaction Network ◽  
Normal Pressure ◽  
Fixed Bed Reactor ◽  
Propane Dehydrogenation ◽  
Coke Deposition ◽  
Formation Kinetic

Pt–Sn/hierarchical SAPO-34 was synthesised and kinetically modelled as an efficient and selective catalyst for propylene production through propane dehydrogenation. The kinetics of the reaction network were studied in an integral fixed-bed reactor at three temperatures of 550, 600 and 650 °C and weight hourly space velocities of 4 and 8 h−1 with a feed containing hydrogen and propane with relative molar ratios of 0.2, 0.5 and 0.8, at normal pressure. The experiments were performed in accordance with the full factorial experimental design. The kinetic models were constructed on the basis of different mechanisms and various deactivation models. The kinetics and deactivation parameters were simultaneously predicted and optimised using genetic algorithm optimisation. It was further proven that the Langmuir–Hinshelwood model can well predict propane dehydrogenation kinetics through lumping together all the possible dehydrogenation steps and also by assuming the surface reaction as the rate-determining step. A coke formation kinetic model has also shown appropriate results, confirming the experimental data by equal consideration of both monolayer and multilayer coke deposition kinetic orders and an exponential deactivation model.

Comparative Study on Hydrotreating of Venezuela De-Asphalted Oil: Conversion Behavior of Heteroatom Compounds and HDM Catalyst Deactivation

2014 ◽  
Vol 926-930 ◽  
pp. 320-324
Author(s):  
Tao Zhang ◽  
Shi Jie Zhou ◽  
Qiang Wei ◽  
Ting Ting Liu ◽  
Wen Wu Zhou ◽  
...  
Keyword(s):  
Catalyst Deactivation ◽  
Coke Formation ◽  
Coke Deposition ◽  
Diffusion Resistance ◽  
Second Stage ◽  
Reaction Severity ◽  
The Stability ◽  
Impurities Removal ◽  
Heteroatom Compounds

A 1000 hour hydrotreating experiment was performed to investigate the hydrotreating behavior of heteroatom compounds (first stage) and HDM catalyst deactivation (second stage) using Venezuela De-Asphalted Oil. The effect of reaction severity on impurities removal was the expected one, the deeper the hydrotreating degree, the higher the conversion of impurities. The Characterization of spent HDM catalyst shows that the content of coke deposition on spent HDM catalyst is only 4 wt% while that of metal is more than 30 wt%. Vanadium compounds in DAO with less diffusion resistance can deposit inside of the HDM catalyst grain. Lower coke formation also retard the HDM catalyst by keeping the diffusion pores and active cites. The removal of asphaltenes largely improved the stability of the HDM catalyst.

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.

scholarly journals Bio-DEE Synthesis and Dehydrogenation Coupling of Bio-Ethanol to Bio-Butanol over Multicomponent Mixed Metal Oxide Catalysts

Catalysts ◽  
2021 ◽  
Vol 11 (6) ◽  
pp. 660
Author(s):  
Izabela S. Pieta ◽  
Alicja Michalik ◽  
Elka Kraleva ◽  
Dusan Mrdenovic ◽  
Alicja Sek ◽  
...  
Keyword(s):  
Active Sites ◽  
Internal Combustion Engines ◽  
Mixed Oxides ◽  
Catalyst Activity ◽  
Product Distribution ◽  
Coke Deposition ◽  
Precipitation Method ◽  
Mixed Metal Oxide ◽  
Low Carbon ◽  
Municipal Solid Wastes

Within the Waste2Fuel project, innovative, high-performance, and cost-effective fuel production methods from municipal solid wastes (MSWs) are sought for application as energy carriers or direct drop-in fuels/chemicals in the near-future low-carbon power generation systems and internal combustion engines. Among the studied energy vectors, C1-C2 alcohols and ethers are mainly addressed. This study presents a potential bio-derived ethanol oxidative coupling in the gas phase in multicomponent systems derived from hydrotalcite-containing precursors. The reaction of alcohol coupling to ethers has great importance due to their uses in different fields. The samples have been synthesized by the co-precipitation method via layered double hydroxide (LDH) material synthesis, with a controlled pH, where the M(II)/M(III) ≈ 0.35. The chemical composition and topology of the sample surface play essential roles in catalyst activity and product distribution. The multiple redox couples Ni2+/Ni3+, Cr2+/Cr3+, Mn2+/Mn3+, and the oxygen-vacant sites were considered as the main active sites. The introduction of Cr (Cr3+/Cr4+) and Mn (Mn3+/Mn4+) into the crystal lattice could enhance the number of oxygen vacancies and affect the acid/base properties of derived mixed oxides, which are considered as crucial parameters for process selectivity towards bio-DEE and bio-butanol, preventing long CH chain formation and coke deposition at the same time.

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