Reactor engineering calculations with a detailed reaction mechanism for the oxidative coupling of methane
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Sonya Rivera
Abstract
The oxidative coupling of methane (OCM) is a potential option for conversion of excess natural gas to higher value products or useful feedstocks. The preferred or ideal OCM stoichiometry is: 2CH4 + O2 → C2H4 + 2H2O, but real OCM produces a variety of species. Using a detailed mechanism from the literature for OCM over a La2O3/CeO2 catalyst that combines coupled elementary gas phase and surface reactions, a reactor engineering study has been done. Adiabatic packed bed reactor (PBR, modeled as plug flow) and continuous stirred tank reactor (CSTR, perfect mixing) simulations using this mechanism are presented. Each reactor simulation used the same total number of catalyst sites. Process variables included CH4/O2 feed ratio (7, 11), feed temperature (843–1243 K), and feed rate. All runs were conducted at 1.01E5 Pa pressure. The results show the CSTR produces high conversions at much lower feed temperatures than those required by the PBR. Once full PBR “light off” occurs, however, its CH4 conversions exceed CSTR. The simulations reveal OCM over this catalyst at these conditions gives a mixture of synthesis gas (CO, H2) and C2Hx (primarily C2H4 plus small quantities of C2H6 and C2H2). The CSTR favors the production of synthesis gas, while the PBR favors C2Hx. Within the suite of CSTR cases, C2Hx is favored at the lowest feed temperature and highest CH4/O2 feed ratio.
Acknowledgment
The authors gratefully acknowledge the support and helpful comments from Dr. Canan Karakaya, Mechanical Engineering Department, Colorado School of Mines.
Author contribution: All the authors have accepted responsibility for the entire content of this submitted manuscript and approved submission.
Research funding: None declared.
Conflict of interest statement: The authors declare no conflicts of interest regarding this article.
Nomenclature for Detchem®
- CSTR
- A
catalytic surface area (m2)
- ck
molar concentration of gas phase species k (moles/m3)
- H
total enthalpy of gas within reactor (J)
inlet or outlet mean molar mass (kg/mole)
- t
time (s)
- V
reactor volume (m3)
inlet or outlet gas volumetric flow rate (m3/s)
- α
coverage relaxation factor
fraction of surface sites covered by adsorbed species k
surface site density (moles/m2)
- PBED
- av
catalytic surface area per unit volume of bed (1/m)
- Cp
mass-weighted mean specific heat (J/kg-K)
- kg
total number of gas species
- Mk
molecular weight of gas species k
- Yk
mass fraction of gas species k
- u
gas superficial velocity (m/s)
- z
axial position (m)
- ε
bed porosity
- ρ
gas mass density (kg/m3)
- Common to PBED and CSTR
- hk
molar enthalpy of gas species k (J/mole)
- T
temperature (K)
species k surface reaction rate (moles/m2-s)
species k gas reaction rate (moles/m3-s)
- Subscripts
- in
inlet
- k
species k
- out
outlet
References
Alexiadis, V., J. Thybaut, P. Kechagiopoulos, M. Chaar, A. Van Veen, M. Muhler, and G. Marin. 2014. “Oxidative Coupling of Methane: Catalytic Behavior Assessment via Comprehensive Microkinetic Modeling.” Applied Catalysis B: Environmental 150–151: 496–505, https://doi.org/10.1016/j.apcatb.2013.12.043.Search in Google Scholar
Aseem, A., G. Jeba, M. Conato, J. Rimer, and M. Harold. 2018. “Oxidative Coupling of Methane over Mixed Metal Oxide Catalysts: Steady State Multiplicity and Catalyst Durability.” Chemical Engineering Journal 331: 132–43, https://doi.org/10.1016/j.cej.2017.08.093.Search in Google Scholar
Beck, B., V. Fleischer, S. Arndt, M. Hevia, A. Urakawa, P. Hugo, and R. Schomacker. 2014. “Oxidative Coupling of Methane – A Complex Surface/gas Phase Mechanism with Strong Impact on the Reaction Engineering.” Catalysis Today 228: 212–8, https://doi.org/10.1016/j.cattod.2013.11.059.Search in Google Scholar
Cernansky, R. 2015. “Natural Gas Boom Brings Major Growth for US Chemical Plants.” Yale Environment 360: 29.Search in Google Scholar
Cruellas, A., T. Melchiori, F. Gallucci, and M. van Sint Annaland. 2017. “Advanced Reactor Concepts for Oxidative Coupling of Methane.” Catalysis Reviews 59 (3): 234–94, https://doi.org/10.1080/01614940.2017.1348085.Search in Google Scholar
Deutschmann, O., S. Tischer, C. Correa, D. Chatterjee, S. Kleditzsch, V. M. Janardhanan, N. Mladenov, H. D. Minh, H. Karadeniz, and M. Hettel. 2014. DETCHEM Software Package, 2.5 ed. Karlsruhe. Also available at www.detchem.com.Search in Google Scholar
Elliott, R. 2019. “The Leaks that Threaten Clean Image of Natural Gas.” Wall Street Journal 10: B4.Search in Google Scholar
Elrod, M. J. 1999. “Greenhouse Warming Potentials from the Infrared Spectroscopy of Atmospheric Gases.” Journal of Chemical Education 76 (12): 1702, https://doi.org/10.1021/ed076p1702.Search in Google Scholar
Farrell, B., V. Igenegbai, and S. Linic. 2016. “A Viewpoint on Direct Methane Conversion to Ethane and Ethylene Using Oxidative Coupling on Solid Catalysts.” ACS Catalysis 6: 4340–6, https://doi.org/10.1021/acscatal.6b01087.Search in Google Scholar
Galadima, A., and O. Muraza. 2016. “Revisiting the Oxidative Coupling of Methane to Ethylene in the Golden Period of Shale Gas: A Review.” Journal of Industrial and Engineering Chemistry 37: 1–13, https://doi.org/10.1016/j.jiec.2016.03.027.Search in Google Scholar
Harder, A. 2015. “EPA to Propose Rules Cutting Methane Emissions from Oil and Gas Drilling.” Wall Street Journal.Search in Google Scholar
Kanellos, M. 2015. The Mind-Boggling Statistics Around Wasted Natural Gas. Forbes. Also available at http://www.forbes.com/sites/michaelkanellos/2015/01/29/the-mind-boggling-statistics-around-wasted-natural-gas/#14587d1a7e18.Search in Google Scholar
Karakaya, C., S. H. Morejudo, H. Zhu, and R. J. Kee. 2016. “Catalytic Chemistry for Methane Dehydroaromatization (MDA) on a Bifunctional Mo/HZM-5 Catalyst in a Packed Bed.” Industrial & Engineering Chemistry Research 55: 9895–906.10.1021/acs.iecr.6b02701Search in Google Scholar
Karakaya, C., H. Zhu, B. Zohour, S. Senkan, and R. J. Kee. 2017. “Detailed Reaction Mechanisms for the Oxidative Coupling of Methane over La2O3/CeO2 Nanofiber Fabric Catalysts.” ChemCatChem 9: 4538–51.10.1002/cctc.201701172Search in Google Scholar
Keller, G. E., and M. M. Bhasin. 1982. “Synthesis of Ethylene via Oxidative Coupling of Methane. I. Determination of Active Catalysts.” Journal of Catalysis 73 (1): 9–19.10.1016/0021-9517(82)90075-6Search in Google Scholar
Noon, D., B. Zohour, and S. Senkan. 2014. “Oxidative Coupling of Methane with La2O3–CeO2 Nanofiber Fabrics: A Reaction Engineering Study.” Journal of Natural Gas Science and Engineering 18: 406–11.10.1016/j.jngse.2014.04.004Search in Google Scholar
NASA. Reaction Equilibrium Calculator. Also available at https://www.grc.nasa.gov/www/CEAWeb/ceaHome.htm.Search in Google Scholar
Nunez, C. 2014. “Oil Drillers’ Burning of Natural Gas Costs U.S. Millions in Revenue.” National Geographic.Search in Google Scholar
Ogihara, H., H. Tajima, and H. Kurokawa. 2020. “Pyrolysis of Mixtures of Methane and Ethane: Activation of Methane with the Aid of Radicals Generated from Ethane.” Reaction Chemistry & Engineering 5 (1): 145–53.10.1039/C9RE00400ASearch in Google Scholar
Stansch, Z., L. Mleczko, and M. Baerns. 1997. “Comprehensive Kinetics of Oxidative Coupling of Methane over the La2O3/CaO Catalyst.” Industrial & Engineering Chemistry Research 36: 2568–79.10.1021/ie960562kSearch in Google Scholar
Yang, S., and R. Dezember. 2019. “The U.S. Is Overflowing with Natural Gas. Not Everyone Can Get it.” Wall Street Journal. Also available at https://www.wsj.com/articles/the-u-s-is-overflowing-with-natural-gas-not-everyone-can-get-it-11562518355.Search in Google Scholar
Zohour, B., D. Noon, and S. Senkan. 2013. “New Insights into the Oxidative Coupling of Methane from Spatially Resolved Concentration and Temperature Profiles.” ChemCatChem 5 (10): 2809–12.10.1002/cctc.201300401Search in Google Scholar
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Articles in the same Issue
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- Application of statistical analysis, Deng’s relevancy and BP neural network for predicting molten iron sulfur in COREX process
- Batch and packed bed techniques for adsorptive aqueous phase removal of selected phenoxyacetic acid herbicide using sugar industry waste ash
- Fluidization characteristics of wide-size-distribution particles in a gas-solid fluidized bed reactor
- Separation of copper and indium from zinc hydrometallurgy solution
- Reactor engineering calculations with a detailed reaction mechanism for the oxidative coupling of methane
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- Esterification of glycerol with acetic acid using a sulfonated polyphenylene sulfide non-woven fabric as a catalyst
- Effect of H/D ratio and impeller type on power consumption of agitator in continuous stirred tank reactor for nitrocellulose production from cotton linter and nitric acid
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