ESR 15

Host institution: LPP – Ecole polytechnique (CNRS – LPP)
Supervisor: Olivier Guaitella
Start date: September 2019
Gross salary: ~27 000 € /year (may vary according to institution).


Title: Role of vibrationally excited molecules on catalytic surfaces

Objectives: 

The purpose of this ESR will be to evaluate the relevance of fluidized bed reactors coupled with non thermal plasmas. The expected advantages would be a better use of the whole mass of catalytic material and a better heat exchange to prevent high temperatures that could promote back reaction from CO to CO2. The fluidized bed regime (FB) can be achieved with well-calibrated particles having sizes from few tens of nm to few microns. The typical gas velocities required to obtain a FB are a few [m/s]. A RF discharge will be ignited in a tube of typically 2 cm inner diameter with gas pressure of a few mbar. In such conditions, typical gas flow of 1 L/min should provide fluidized regime. For a good recirculation with heavier particles, gas flow of 10 L/min will be necessary. In the DBD reactor, with 1 mm gap and 2 cm width, a gas flow of 5 L/min should provide a gas velocity about 4 m/s that is given in the literature as a typical value for obtaining fluidized bed. Special care will be taken for the gas distributor at the bottom of the reactor. Most of the studies dedicated to fluidized beds are dealing with large dimensions. The behavior of small dimensions reactor, with particles charges by the plasma will be completely new but it is probable that the strong influence of the wall will favor captive regimes unless electrostatic phenomena can increase the circulation of particles.

The particles used will be developed and calibrated at UoB. They will have a large content of MgO not only for their catalytic activity also studied in other ESRs of PIONEER but also because MgO is a very efficient secondary electron emitter that could promote homogeneous discharge at elevated pressure. The gas mixtures studied will first be pure CO2, but then will move towards CO2/H2O and CO2/H2

Characterization of gas phase species but also of particles by DRIFT and transmission FTIR will be performed and gas temperature measurement in the reactor, as well as a variety of surface diagnostics at UoB.

Links with other ESRs: Comparison with CO2 conversion efficiency obtained in conventional DBD reactors from ESRs 6-10

Expected Results:

  • Relevance of fluidized bed reactor coupled with plasma for CO2 conversion
  • Obtaining discharge with lower electric field at atmospheric pressure or close to atmospheric pressure

Co-supervisor: Vasile Parvulescu (UoB), 18 months The ESR will be learning how to develop the catalyst and characterize them at the University of Bucarest (UoB).

Industrial partner: Solayl will provide its expertise for power measurements in the difficult condition of a fluidized bed reactor (2 months)