CO2 conversion in nonuniform discharges: disentangling dissociation and recombination mechanisms

This archive contains supplementary data associated with the following publication:

Title:   CO2 Conversion in Nonuniform Discharges: Disentangling Dissociation and Recombination Mechanisms
Authors: A.J. Wolf, F.J.J. Peeters, P.W.C. Groen, W.A. Bongers, and M.C.M. van de Sanden
Journal: The Journal of Physical Chemistry C
Date of publication: July 14, 2020
DOI: https://dx.doi.org/10.1021/acs.jpcc.0c03637

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ABSTRACT
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Motivated by environmental applications such as synthetic fuel synthesis, plasma-driven conversion shows promise for efficient and scalable gas-conversion of CO2 to CO. Both discharge contraction and turbulent transport have a significant impact on the plasma processing conditions, but are, nevertheless, poorly understood. This work combines experiments and modeling to investigate how these aspects influence the CO production and destruction mechanisms in the vortex-stabilized CO2 microwave plasma reactor. For this, a two-dimensional axisymmetric tubular chemical kinetics model of the reactor is developed, with careful consideration of the non-uniform nature of the plasma and the vortex-induced radial turbulent transport. Energy efficiency and conversion of the dissociation process show a good agreement with the numerical results over a broad pressure range from 80 - 600mbar. The occurrence of an energy efficiency peak between 100 - 200 mbar is associated with a discharge mode transition. The net CO production rate is inhibited at low pressure by the plasma temperature, while recombination of CO back to CO2 dominates at high pressure. Turbulence-induced cooling and dilution of plasma products limit the extent of the latter. The maxima in energy efficiency observed experimentally around 40% are related to limits imposed by production and recombination processes. Based on these insights, feasible approaches for optimization of the plasma dissociation process are discussed.
 

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STRUCTURE AND CONTENT OF THE SUPPLEMENTARY DATA
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The data and numerical code used to produce Figs. 6-16 in the publication are structured as listed below. The reactor model has been carried out in Wolfram Mathematica 11, as detailed in the publication. The code is available upon request by contacting the corresponding authors. The thermodynamics calculations regarding the quenching scenarios are carried out in python 3.7 using the thermodynamic equilibrium solver of the Cantera chemical kinetics library.

DIRECTORY     |  DESCRIPTION
.\reactor_model  |  input files and simulation results used to produce Figs. 6 - 14
.\experimental   |  experimental data used in Fig 15
.\thermodynamics |  thermodynamic calculations (python code and input file) used to produce Fig. 16
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TERMS OF USE
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The data contained in this repository is published under a Creative Commons Attribution 4.0 license.