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Catalytic Reactors and Hybrid Processes

Contact : Carine JULCOUR

Studying transfer mechanisms and their coupling with reactions for innovative catalytic systems and original hybrid reactors

- This research covers 3 sub-topics:

  • metrology and numerical tools for the local analysis of hydrodynamics and mass transfer in multiphase gas-liquid-(solid) reactors,
  • multiphase processes for homogeneous catalysis,
  • design, modeling and hybridization of bubble column, fixed bed and structured gas-liquid reactors.

Study of mass transfer in Taylor flow using the PLIF-I technique: dissolved gas concentration.

Hybridising operations to improve (catalytic) multiphase processes

- Monolithic reactor-heat exchanger for three-phase catalytic reactions

  • In the ANR project Hydromore, an intensified monolithic reactor for the (selective) hydrogenation of bio-sourced products is studied. The challenges are first technological with the design and realization of a heat-conducting reactor that includes channels with catalytic walls and channels for cooling, as well as a specific device to ensure an even distribution of the fluids towards the catalytic channels and the so-called Taylor flow regime.
  • Concerning modeling, the difficulty stands in the strong coupling that exists between reaction, heat and mass transfer and hydrodynamics, which must be described at various scales: the lubricating film at the gas-liquid interface, the catalytic channel, and the whole reactor.

- CO2 sequestration using an attrition reactor for the accelerated leaching of minerals

  • The ANR project CARMEX found an innovative solution for direct aqueous mineral carbonation, which involves concomitant exfoliation and mineralization [1]. This solution overcomes a major limitation in silicate mineralization: the precipitation of passivating layers at the material surface during dissolution.
  • The proof of concept of the continuous attrition of these passivation layers was achieved in an autoclave reactor transformed into an agitated ball mill. Our aim is now to extend this process to various materials, then to study its scale-up for continuous operation and its optimization.

Stirred multiphase reactor under pressure.

Assessing and analyzing new systems for homogeneous multiphase catalysis

- Different strategies are studied to achieve an efficient immobilization of homogeneous catalysts (allowing for their separation from the products and their recycling), while maintaining high reaction rates: supported ionic liquid phase catalysis and aqueous biphasic catalysis with amphiphilic polymeric ligands.
- En collaboration avec le NCL Pune (projet CEFIPRA 3305-2), le LCC Toulouse et le C2P2 Lyon (ANR Biphasnanocat), nous caractérisons l’activité catalytique, la sélectivité et la perte en métal de ces systèmes. Les études utilisent comme réaction modèle l’hydroformylation de l’oct-1-ène en n-nonanal catalysée par le rhodium. Des activités catalytiques élevées (TOF dépassant 500 h-1) ont pu être mises en évidence à la fois pour le catalyseur à phase liquide ionique supportée et le polymère coeur-coquille, grâce à la création d’un environnement favorable, riche en oléfine, à proximité du métal.
- The model reaction is the rhodium-catalyzed hydroformylation of 1-octene to n-nonanal. High catalytic activities (TOF exceeding 500 h-1) are obtained for both the supported ionic liquid phase catalyst and for the core-shell polymer through the creation of a favorable (olefin-rich) environment in the vicinity of the metal.
- A thorough kinetic study was carried out in ionic liquids, involving the measurements of partition coefficients of the substrate/product between the ionic liquid and the organic phase (by multiple headspace-gas chromatography) and the derivation of rate laws from reaction mechanisms (using the “Christiansen matrix” approach). The effect of the gas-liquid transfer has also been modeled using reaction experiments under slow stirring and mass transfer measurements. We investigated the influence of the core-shell polymer architecture on the activity, selectivity and stability of the resulting catalysts, providing clues for their optimization. Further studies on coreshell polymers are aiming to elucidate mass transfer mechanisms and to model the reaction kinetics, which implies analysis of the microenvironment composition.

Biphasic (organic/aqueous) reaction system with core-shell polymers.