Version française
RSS feeds
Accueil
Home > Expertise > Research divisions > Process Experiments > Complex reactions? Supercritical microfluidics to the rescue!

Process Experiments

Complex reactions? Supercritical microfluidics to the rescue!

Thesis by Bruno Pinho Da Silva*

Propylene is a key chemical intermediate produced through catalyzed selective hydrogenation of hydrocarbons (C3 fractiona).

Studying the consequent reaction is complex as it is an extremely quick, triphasic (gas-liquid-solid) reaction. To better understand this reaction, studies aiming to improve the catalysts have been carried out in a single pellet string reactor, in supercritical phaseb.

a - Mix of hydrocarbons composed of molecules containing three carbon atoms
   
b - Monophasic intermediary state between gas and liquid

This requires precise knowledge of the thermodynamic conditions (P,T) at which the real hydrocarbons/hydrogen mixes under study reach this supercritical state.

Appropriate operating conditions can then be set to guarantee the desired state for the reactants within the reactor.

During this thesis, an original methodology for determining the "supercritical point" was successfully developed(1). It is based on the use of a microfluidic device —high pressure and high temperature — on a silica/alumina chip, allowing thermodynamic data to be acquired quickly for a given reaction mixture.

After the mix to be tested has been injected into the chip, the temperature is increased at constant pressure until the boiling and dew points can be observed. The procedure is repeated at different pressures to obtain the range within which the mixture reaches its super-critical point.

In these operating conditions, studies using a single pellet string reactor have shown:

  • the intrinsic performances of the catalyst,
  • and provided a better understanding of the reaction system.

Managing the gas/liquid mass transfer was thus revealed as a key for the productivity of the process.

This methodology, in addition to being appropriate for other industrial processes, has proven that the use of a microfluidic chip is a quick, precise and inexpensive means which can be used for determining other types of physicochemical properties(2).

 

Scientific contact:  ghislain.bergeot@ifpen.fr

Published in Science@ifpen n° 27 - December 2016

* Thesis entitled “Specific properties of super-critical fluids for fast and exothermic reactive systems”

Publications

  1. B. Pinho, S. Girardon, F. Bazer-Bachi, G. Bergeot, S. Marre, C. Aymonier,
    A microfluidic approach for investigating multicomponent system thermodynamics at high pressures and temperatures, Lab on a chip 2014, 14 (19), 3843–3849.
    >> DOI: 10.1039/c4lc00505h
      
  2. B. Pinho, S. Girardon, F. Bazer-Bachi, G. Bergeot, S. Marre, C. Aymonier, Simultaneous measurement of fluids density and viscosity using HP/HT capillary devices, The Journal of Supercritical Fluids 2015.
    >> DOI: 10.1016/j.supflu.2015.04.016
      

links list

  • Print page