scholarly journals Comparative Study Between two Reaction Kinetic Mechanisms of Thiophene Hydrodesulphurization over CoMo /gama - Al2O3 Supported Catalyst

2019 ◽  
Vol 70 (7) ◽  
pp. 2481-2484
Author(s):  
Rami Doukeh ◽  
Mihaela Bombos ◽  
Ion Bolocan
Keyword(s):  
Active Sites ◽  
Reaction Kinetic ◽  
Supported Catalyst ◽  
Calculated Data ◽  
Space Velocity ◽  
Thiophene Hydrodesulfurization ◽  
Liquid Hourly Space Velocity ◽  
Kinetic Mechanisms ◽  
Kinetics Of ◽  
Al2o3 Catalyst

The kinetic study of the thiophene hydrodesulphurisation process was carried out for CoMo/gama-Al2O3 catalyst, at temperatures between 175 and 275 �C, pressure ranged from 30bar to 60 bar and the liquid hourly space velocity from 1h-1 to 4 h-1. For the reaction mechanism, the Langmuir-Hinshelwood-Hougen-Watson model (LHHW) was used and two kinetic models were proposed: the first model, that considered that H2 is adsorbed on a different type of active center than thiophene and the second model, that considered that the two reactants are adsorbed on the same type of active sites. The values obtained for the average relative error (ARE) and the correlation coefficient between the experimental and the calculated data (R2) indicate that the Langmuir-Hinshelwood model, describing the adsorption on two active sites, best describes the kinetics of the thiophene hydrodesulfurization reaction over CoMo/gama-Al2O3 tested catalyst.

Dimethyldisulphide Hydrodesulphurization on NiCoMo / Al2O3 Catalyst

2017 ◽  
Vol 68 (7) ◽  
pp. 1496-1500
Author(s):  
Rami Doukeh ◽  
Mihaela Bombos ◽  
Ancuta Trifoi ◽  
Minodora Pasare ◽  
Ionut Banu ◽  
...  
Keyword(s):  
Good Accuracy ◽  
Fixed Bed ◽  
Continuous System ◽  
Space Velocity ◽  
Molar Ratio ◽  
Catalytic Reactor ◽  
Liquid Hourly Space Velocity ◽  
Hydrodesulfurization Process ◽  
Al2o3 Catalyst ◽  
Simplified Kinetic Model

Hydrodesulphurization of dimethyldisulphide was performed on Ni-Co-Mo /�-Al2O3 catalyst. The catalyst was characterized by determining the adsorption isotherms, the pore size distribution and the acid strength. Experiments were carried out on a laboratory echipament in continuous system using a fixed bed catalytic reactor at 50-100�C, pressure from 10 barr to 50 barr, the liquid hourly space velocity from 1h-1 to 4h-1 and the molar ratio H2 / dimethyldisulphide 60/1. A simplified kinetic model based on the Langmuir�Hinshelwood theory, for the dimethyldisulphide hydrodesulfurization process of dimethyldisulphide has been proposed. The results show the good accuracy of the model.

Hydroisomerization of Biomass Derived n-Hexadecane Towards Diesel Pool: Effect of Selective Removal External Surface Sites from Pt/ZSM-22

2016 ◽  
Vol 14 (1) ◽  
pp. 155-165 ◽  
Author(s):  
Abhijeet H. Thaker ◽  
Mathew John ◽  
Kishore Kumar ◽  
Mahesh W. Kasture ◽  
Snehalkumar Parmar ◽  
...  
Keyword(s):  
Oxalic Acid ◽  
Active Sites ◽  
External Surface ◽  
Space Velocity ◽  
Product Distribution ◽  
Catalytic Performance ◽  
Selective Removal ◽  
Cold Flow ◽  
External Site ◽  
Kinetics Of

AbstractInfluence of dealumination of zeolite ZSM-22 (Si/Al ratio of 45) by treating it with oxalic acid on its catalytic performance in n-hexadecane hydroisomerization reaction was studied. This reaction is an attempt in the direction of green and sustainable source of diesel via improving the cold-flow properties of deoxygenated vegetable oils. Pt (0.5 wt%) on ZSM-22 treated with 1 M oxalic acid afforded highest yields of the mono-branched paraffins. This improved is attributed to selective removal of active sites on external surface of zeolite crystals (responsible for undesired cracking reactions) using the bulkier dealuminating agent, oxalic acid. Thus, pore-mouth key-lock mechanism was brought to play the role to cause high selectivity to mono-branched isomers. Preferential external site deactivation was inferred from mesitylene cracking results. Effects of operating parameters such as temperature, and space velocity on product distribution also were studied. Also, kinetics of the reactions involved too has been in brief reported.

scholarly journals Optimization of Bio-Hydrogenated Kerosene from Refined Palm Oil by Catalytic Hydrocracking

Energies ◽  
2019 ◽  
Vol 12 (16) ◽  
pp. 3196 ◽  
Author(s):  
Praepilas Dujjanutat ◽  
Arthit Neramittagapong ◽  
Pakawadee Kaewkannetra
Keyword(s):  
Palm Oil ◽  
Freezing Point ◽  
Reaction Pathway ◽  
Space Velocity ◽  
Mass Percentage ◽  
Carbon Loss ◽  
Heating Value ◽  
Box Behnken Design ◽  
Liquid Hourly Space Velocity ◽  
Al2o3 Catalyst

In this work, hydro-processing was used as an alternative route for producing bio-hydrogenated kerosene (BHK) from refined bleached deodorized palm oil (RPO) in the presence of a 0.5 wt% Pd/Al2O3 catalyst. The Box-Behnken Design was used to determine the effects of reaction temperature, H2 pressure, and reaction time in terms of liquid hourly space velocity (LHSV) on BHK production. The kerosene selectivity was used as the response for staticial interpretation. The results show that both temperature and LHSV produced significant effects, whereas H2 pressure did not. The optimal conditions were found to be 483 °C, 5.0 MPa, and 1.4 h−1 LHSV; these conditions provided approximately 57.30% kerosene selectivity and a 47.46% yield. The BHK product had a good heating value and flash point. However, the mass percentage of carbon and hydrogen was 99.1%, which is just below the minimum standard (99.5%), according to the carbon loss by the reaction pathway to form as CO and CO2. Water can be produced from the reaction induced by oxygen removal, which results in a high freezing point.

Modeling the kinetics of sulfidation over NiMo/Al2O3 catalyst for thiophene hydrodesulfurization

2015 ◽  
Vol 115 (2) ◽  
pp. 635-649 ◽  
Author(s):  
Weikun Lai ◽  
Yingrui Xu ◽  
Yusheng Zhao ◽  
Jinbao Zheng ◽  
Xiaodong Yi ◽  
...  
Keyword(s):  
Thiophene Hydrodesulfurization ◽  
Kinetics Of ◽  
Al2o3 Catalyst

scholarly journals Liquid-Phase Hydrogenation of 1-Phenyl-1-propyne on the Pd1Ag3/Al2O3 Single-Atom Alloy Catalyst: Kinetic Modeling and the Reaction Mechanism

Nanomaterials ◽  
2021 ◽  
Vol 11 (12) ◽  
pp. 3286
Author(s):  
Alexander V. Rassolov ◽  
Igor S. Mashkovsky ◽  
Galina N. Baeva ◽  
Galina O. Bragina ◽  
Nadezhda S. Smirnova ◽  
...  
Keyword(s):  
Reaction Mechanism ◽  
Liquid Phase ◽  
Reaction Kinetic ◽  
Single Atom ◽  
Kinetic Characteristics ◽  
Liquid Phase Hydrogenation ◽  
Alkyne Hydrogenation ◽  
Kinetics Of ◽  
Al2o3 Catalyst ◽  
Single Atom Alloy

This research was focused on studying the performance of the Pd1Ag3/Al2O3 single-atom alloy (SAA) in the liquid-phase hydrogenation of di-substituted alkyne (1-phenyl-1-propyne), and development of a kinetic model adequately describing the reaction kinetic being also consistent with the reaction mechanism suggested for alkyne hydrogenation on SAA catalysts. Formation of the SAA structure on the surface of PdAg3 nanoparticles was confirmed by DRIFTS-CO, revealing the presence of single-atom Pd1 sites surrounded by Ag atoms (characteristic symmetrical band at 2046 cm−1) and almost complete absence of multiatomic Pdn surface sites (<0.2%). The catalyst demonstrated excellent selectivity in alkyne formation (95–97%), which is essentially independent of P(H2) and alkyne concentration. It is remarkable that selectivity remains almost constant upon variation of 1-phenyl-1-propyne (1-Ph-1-Pr) conversion from 5 to 95–98%, which indicates that a direct alkyne to alkane hydrogenation is negligible over Pd1Ag3 catalyst. The kinetics of 1-phenyl-1-propyne hydrogenation on Pd1Ag3/Al2O3 was adequately described by the Langmuir-Hinshelwood type of model developed on the basis of the reaction mechanism, which suggests competitive H2 and alkyne/alkene adsorption on single atom Pd1 centers surrounded by inactive Ag atoms. The model is capable to describe kinetic characteristics of 1-phenyl-1-propyne hydrogenation on SAA Pd1Ag3/Al2O3 catalyst with the excellent explanation degree (98.9%).

Catalytic Neutralization of Naphthenic Acid from Petroleum Crude Oil by Using Cerium Oxide Catalyst and 2- Methylimidazole in Polyethylene Glycol

2020 ◽  
Vol 13 ◽  
Author(s):  
Norshahidatul Akmar Mohd Shohaimi ◽  
Norfakhriah Jelani ◽  
Ahmad Zamani Ab Halim ◽  
Nor Hakimin Abdullah ◽  
Nurasmat Mohd Shukri
Keyword(s):  
Polyethylene Glycol ◽  
Crude Oil ◽  
Cerium Oxide ◽  
Active Sites ◽  
Naphthenic Acid ◽  
Naphthenic Acids ◽  
Catalyst Loading ◽  
High Concentration ◽  
Oil Refineries ◽  
Al2o3 Catalyst

: The presence of relatively high naphthenic acid in crude oil may contribute to the major corrosion in oil pipelines and distillation units in crude oil refineries. Thus, high concentration Naphthenic Acids crude oil is considered tobe of low quality and is marketed at lower prices. In order to overcome this problem, neutralization method had been developed to reduce the TAN value in crude oil. In this study, crude oil from Petronas Penapisan Melaka was investigated. The parameters studied were reagent concentration, catalyst loading, calcination temperature and reusability of the potential catalyst. Basic chemical used were 2- methylimidazole in polyethylene glycol (PEG 600) with concentration 100, 500 and 1000 ppm. Cerium oxide-based catalysts supported onto alumina prepared with different calcination temperatures. The catalyst was characterized by using Brunauer-Emmett-Teller (BET), Fourier Transform Infrared Spectroscopy (FTIR) and Thermogravimetry Analysis-Differential Thermal Gravity (TGA-DTG) to study physical properties of the catalyst. The Ce/Al2O3 catalyst calcined at 1000°C was the best catalyst due to larger surface area formation which lead to increment of active sites thus will boost the catalytic activity. The result showed that the Ce/Al2O3 catalyst meet Petronas requirement as the TAN value reduced to 0.6 mgKOH/g from original TAN value of 4.22 mgKOH/g. The best reduction of TAN was achieved by using catalyst loading of 0.39% and reagent of 1000 ppm.

Kinetics of the catalytic hydrodesulphurization reaction system; hydrogenolysis of thiophene

1980 ◽  
Vol 45 (10) ◽  
pp. 2728-2741 ◽  
Author(s):  
Pavel Fott ◽  
Petr Schneider
Keyword(s):  
Atmospheric Pressure ◽  
Active Sites ◽  
Flow Reactor ◽  
Kinetic Equations ◽  
Reaction System ◽  
Reaction Products ◽  
Molybdenum Catalyst ◽  
Cobalt Molybdenum Catalyst ◽  
Kinetics Of ◽  
Reaction Schemes

Kinetics have been studied of the reaction system taking place during the reaction of thiophene on the cobalt-molybdenum catalyst in a gradientless circulation flow reactor at 360 °C and atmospheric pressure. Butane has been found present in a small amount in the reaction products even at very low conversion. In view of this, consecutive and parallel-consecutive (triangular) reaction schemes have been proposed. In the former scheme the appearance of butane is accounted for by rate of desorption of butene being comparable with the rate of its hydrogenation. According to the latter scheme part of the butane originates from thiophene via a different route than through hydrogenation of butene. Analysis of the kinetic data has revealed that the reaction of thiophene should be considered to take place on other active sites than that of butene. Kinetic equations derived on this assumption for the consecutive and the triangular reaction schemes correlate experimental data with acceptable accuracy.

Kinetics of catalytic reduction of nitrogen oxide by carbon monoxide on CuO/Al2O3 catalyst

1983 ◽  
Vol 48 (11) ◽  
pp. 3202-3208 ◽  
Author(s):  
Zdeněk Musil ◽  
Vladimír Pour
Keyword(s):  
Carbon Monoxide ◽  
Nitrogen Oxide ◽  
Rate Equation ◽  
Catalytic Reduction ◽  
Zero Order ◽  
Spectroscopic Measurements ◽  
First Order ◽  
Ir Spectroscopic ◽  
Kinetics Of ◽  
Al2o3 Catalyst

The kinetics of the reduction of nitrogen oxide by carbon monoxide on CuO/Al2O3 catalyst (8.36 mass % CuO) were determined at temperatures between 413 and 473 K. The reaction was found to be first order in NO and zero order in CO. The observed kinetics are consistent with a rate equation derived from a mechanism proposed on the basis of IR spectroscopic measurements.

Polymer structure and catalytic activity of ion exchangers

1981 ◽  
Vol 46 (7) ◽  
pp. 1577-1587 ◽  
Author(s):  
Karel Jeřábek
Keyword(s):  
Catalytic Activity ◽  
Ethyl Acetate ◽  
Active Sites ◽  
Crosslinking Agent ◽  
Reaction Medium ◽  
Polymer Structure ◽  
Local Concentration ◽  
Ion Exchangers ◽  
Styrene Divinylbenzene ◽  
Kinetics Of

Catalytic activity of ion exchangers prepared by partial sulphonation of styrene-divinylbenzene copolymers in reesterifications of ethyl acetate by methanol and propanol, hydrolysis of ethyl acetate and in synthesis of bisphenol A has been compared with data on polymer structure of these catalysts and with distribution of the crosslinking agent, divinylbenzene, calculated from literature data on kinetics of copolymerisation of styrene with divinylbenzene. It was found that the polymer structure of ion exchangers influences catalytic activity predominantly by changing the local concentration of acid active sites. The results obtained indicated that the effect of transport phenomena on the rate of catalytic reactions does not depend on the degree of swelling of the ion exchangers in reaction medium but it is mainly dependent on the relative affinity of reaction components to the acid groups or to the polymer skeleton.

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