Effect of Multifunctional Nanocatalysts on n-C7Asphaltene Adsorption and Subsequent Oxidation under High-Pressure Conditions. Medina, O.; Gallego, J.; Olmos, C.; Chen, X.; Cortés, F.; and Franco, C. Energy and Fuels, 34(5):6261-6278, 2020. cited By 4
Effect of Multifunctional Nanocatalysts on n-C7Asphaltene Adsorption and Subsequent Oxidation under High-Pressure Conditions [link]Paper  doi  abstract   bibtex   
This study was carried out to evaluate the effect of high pressure on the oxidation kinetics of n-heptane asphaltenes in the presence and absence of AuPd/Ce0.62Zr0.38O2 catalysts. Bimetallic Au-Pd catalysts with Au/Pd molar ratios from 3.5 to 9.6 were synthesized by deposition-precipitation of Au and followed by incipient wetness impregnation of Pd (3:1AuPd and 10:1AuPd). Adsorption isotherms between hydrocarbons and nanocatalysts were constructed varying the initial asphaltene concentration from 100 to 1500 mg·L-1. Subsequent oxidation was evaluated using thermogravimetric analysis under an air atmosphere, at different pressures from 0.084 to 6.0 MPa in a wide temperature range between 100 and 800 °C. Kinetic parameters were calculated using a first-order kinetic model, considering the system pressure. Adsorption affinity increases in the order support < 3:1AuPd < 10:1AuPd. The catalytic activity of the nanocatalyst was highly dependent on the employed temperature and pressure. Their presence reduces the n-C7 asphaltene decomposition temperature from 450 °C to temperatures below 200 °C for all catalysts used at 6.0 MPa. The main decomposition peaks are presented at 150, 170, and 210 °C for 10:1AuPd, 3:1AuPd, and support, at 6.0 MPa, respectively. Besides, the oxygen chemisorption (OC) region is favored as the material has a greater catalytic activity, increasing from 9.0 to 14.0% (on the load asphaltene basis calculation) for the support and 10:1AuPd catalyst. This was corroborated by the activation energy, which is reduced by more than 30% for all pressures evaluated with the best system. Besides, 89.0 and 80.0% of the mass are lost in the decomposition of the chemisorbed oxygen (DCO) thermal event for the 10:1AuPd and 3:1AuPd nanocatalysts, respectively. Finally, first and second combustions were carried out at temperatures below 240 °C at 6.0 MPa for the 10:1AuPd system, which is a very promising result to determine the reaction pathway for the heavy and extraheavy crude oils during EOR application. Copyright © 2020 American Chemical Society.
@ARTICLE{Medina20206261,
author={Medina, O.E. and Gallego, J. and Olmos, C.M. and Chen, X. and Cortés, F.B. and Franco, C.A.},
title={Effect of Multifunctional Nanocatalysts on n-C7Asphaltene Adsorption and Subsequent Oxidation under High-Pressure Conditions},
journal={Energy and Fuels},
year={2020},
volume={34},
number={5},
pages={6261-6278},
doi={10.1021/acs.energyfuels.0c00653},
note={cited By 4},
url={https://www.scopus.com/inward/record.uri?eid=2-s2.0-85085168589&doi=10.1021%2facs.energyfuels.0c00653&partnerID=40&md5=7fe14746c4b7e5478ccb03d47254d9cd},
abstract={This study was carried out to evaluate the effect of high pressure on the oxidation kinetics of n-heptane asphaltenes in the presence and absence of AuPd/Ce0.62Zr0.38O2 catalysts. Bimetallic Au-Pd catalysts with Au/Pd molar ratios from 3.5 to 9.6 were synthesized by deposition-precipitation of Au and followed by incipient wetness impregnation of Pd (3:1AuPd and 10:1AuPd). Adsorption isotherms between hydrocarbons and nanocatalysts were constructed varying the initial asphaltene concentration from 100 to 1500 mg·L-1. Subsequent oxidation was evaluated using thermogravimetric analysis under an air atmosphere, at different pressures from 0.084 to 6.0 MPa in a wide temperature range between 100 and 800 °C. Kinetic parameters were calculated using a first-order kinetic model, considering the system pressure. Adsorption affinity increases in the order support < 3:1AuPd < 10:1AuPd. The catalytic activity of the nanocatalyst was highly dependent on the employed temperature and pressure. Their presence reduces the n-C7 asphaltene decomposition temperature from 450 °C to temperatures below 200 °C for all catalysts used at 6.0 MPa. The main decomposition peaks are presented at 150, 170, and 210 °C for 10:1AuPd, 3:1AuPd, and support, at 6.0 MPa, respectively. Besides, the oxygen chemisorption (OC) region is favored as the material has a greater catalytic activity, increasing from 9.0 to 14.0% (on the load asphaltene basis calculation) for the support and 10:1AuPd catalyst. This was corroborated by the activation energy, which is reduced by more than 30% for all pressures evaluated with the best system. Besides, 89.0 and 80.0% of the mass are lost in the decomposition of the chemisorbed oxygen (DCO) thermal event for the 10:1AuPd and 3:1AuPd nanocatalysts, respectively. Finally, first and second combustions were carried out at temperatures below 240 °C at 6.0 MPa for the 10:1AuPd system, which is a very promising result to determine the reaction pathway for the heavy and extraheavy crude oils during EOR application. Copyright © 2020 American Chemical Society.},
keywords={Activation energy;  Adsorption;  Asphaltenes;  Atmospheric temperature;  Binary alloys;  Catalyst activity;  Cerium alloys;  Chemisorption;  Gold alloys;  Heptane;  High pressure effects;  Kinetic parameters;  Molar ratio;  Nanocatalysts;  Oxidation;  Oxygen;  Thermogravimetric analysis;  Zircaloy, Asphaltene decomposition;  Deposition precipitation;  Effect of high pressure;  First-order kinetic models;  High-pressure condition;  Incipientwetness impregnation;  Temperature and pressures;  Wide temperature ranges, Palladium alloys},
document_type={Article},
source={Scopus},
}
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