Superlocal chemical reaction equilibrium in low temperature plasma


Uner N. B. , Thimsen E.

AICHE JOURNAL, vol.66, no.6, 2020 (Journal Indexed in SCI) identifier identifier

  • Publication Type: Article / Article
  • Volume: 66 Issue: 6
  • Publication Date: 2020
  • Doi Number: 10.1002/aic.16948
  • Title of Journal : AICHE JOURNAL
  • Keywords: CO2 splitting, low-pressure reactor, low-temperature plasma, plasma chemistry, superlocal equilibrium, RADIOFREQUENCY ELECTRIC-DISCHARGE, CARBON-DIOXIDE, CO2 CONVERSION, PHOTOCATALYTIC REDUCTION, SAHA EQUATION, KINETICS, DECOMPOSITION, DISSOCIATION, OXIDATION, MONOXIDE

Abstract

Low temperature plasmas (LTP) are a unique class of open-driven systems in which chemical reactions are unpredictable using established concepts. The terminal state of chemical reactions in LTP, termed the superlocal equilibrium state, is hypothesized to be defined by a proposed set of state variables. Using a LTP reactor wherein the state variables have been measured, it is shown that CO2 spontaneously splits and the effluent speciation is independent of the influent speciation if the state variables are held constant and the residence time is long. CO2 conversion at long residence times, which is expected to be nominally zero from equilibrium thermodynamics, can be as high as 70% in the LTP. The employed low pressure plasma reactor (P = 10 mbar) had a similar volume, productivity, and energy efficiency compared to an atmospheric pressure dielectric barrier discharge reactor, thanks to reaction rates that were three orders of magnitude faster.