Propositions de contrats Post-Doctoral

Le M2P2 recrute, tout au long de l'année, des post-doctorants en CDD (contrats temporaires de chercheur) dans le cadre des projets de recherche du laboratoire.

Le recrutement post-doctoral sur contrat est destiné aux jeunes docteurs pour leur permettre de :

  • réaliser une mobilité dans le cadre de leur formation
  • d'acquérir une expérience complémentaire de recherche
  • se préparer à un recrutement ultérieur dans une entreprise ou dans un laboratoire académique

2025

  • Feedstock characterization and optimization of efficient mix for reducing inorganic gaseous pollutants in gasification

    I. Context

    The position is in the frame of a national work program funded by the French National Research Agency. Consortium is made up of an academic laboratory (M2P2, Aix-Marseille Université) and ENGIE Lab CRIGEN (Centre de Recherche et Innovation Gaz et Energies Nouvelles), the ENGIE Group's centre for research and operational expertise dedicated to gas, new energies and emerging technologies. The aim of the TIGRE project is to develop effective methods for full-scale modelling of the behavior of inorganic compounds in gasification reactors, taking into account the hydrodynamics of the system, heat transfer and the chemical nature of the various phases. You will be integrated in a pluri-disciplinary team with experts in the field of gasification and solid characterization. The project fits with the need to reduce dependence on fossil fuels and thus to the decrease of the environmental footprint of energy sector which is of major importance.

    II. Scientific issues

    The thermal gasification of waste represents a promising avenue for sustainable energy production and waste valorization. However, the formation of unwanted by-products coming from the inorganics elements originally present in feedstock constitutes a significant hurdle for process design and optimization. Addressing these scientific bottlenecks requires a combination of experimental research and advanced modeling techniques to enhance gasification efficiency and improve the quality of the resulting syngas. Indeed, the syngas quality is directly correlated to the non-content of compounds such as sulfur or chlorine. A large bench of analytical apparatus has been deployed for understanding behaviors and interactions of mineral matter during gasification. This includes the characterization and the definition of the initial feed, and the characterization of all mineral phase formed during the process.
    During pyro-gasification, the inorganic components of biomass undergo diverse transformations depending on whether they are naturally embedded within the biomass matrix (autogenic origin) or externally introduced (technogenic origin or contaminants). In this context, the fluidized bed material is considered part of the externally added inorganic matter. Owing to its elemental composition and catalytic behavior, it can sometimes exhibit higher reactivity than other forms of debris or technogenic materials, thereby influencing the evolution of both the organic and inorganic fractions during gasification. The progression of these changes in the inorganic fraction remains unknown.
    A portion of the inherent inorganic matter may volatilize during devolatilization, later condensing as fine particulates or reacting with external inorganic phases—whether solid or molten—to form slag or agglomerated structures. Some of the native inorganic elements that do not volatilize immediately may be transferred into the gas or vapor phases during rapid pyrolysis and gasification. These transitions are enhanced by reactions involving oxidants, syngas, char, and tar. Simultaneously, structural changes in the organic matrix facilitate the migration and proximity of certain inorganic species, allowing them to interact and produce either low-melting compounds or chemically stable phases. As gasification consumes the organic matrix, these transformations culminate in ash formation. The ash, through interactions with both molten and solid phases of the endogenous and exogenous mineral matter, can contribute further to agglomeration.
    The consumption of the fluidized bed material produces ash that actively promotes tar reforming and enhances the breakdown of char. Furthermore, remnants of the fluidized medium can come into contact with the surface-exposed endogenous minerals, driven there by prior migration mechanisms. Due to the catalytic nature of the metallic elements in these residues, their presence can increase the molten fraction on the char surface, encouraging the formation of a coating. This coated char, along with the resulting ashes from both internal and external inorganic sources, forms a sticky, softened layer under pyro-gasification conditions. These residues can adhere—partially or fully—to the surfaces of the bed particles, fostering sintering between char and bed grain interfaces and ultimately leading to agglomerate formation.
    The innovation of this work is the investigation of the possible interaction of added waste containing different minerals to the main feed to decrease volatility of overall mineral or to increase their capture during the process. Additionally, you could set the definition of mixing rules of different waste to mitigate mineral composition. By combining several analytical techniques and chemometrics, we aimed at the design of solid preparation strategies and optimization of feed mixture.
    The research proposed in this postdoc is at the frontier of chemistry and chemical engineering.
    In a first period, uou will have to perform and understand the characterization with most UpToDate analytical apparatus (SEM-EDX, XRD, elemental analyzer, ICP, μ-XRF, Sequential extraction … ) on different solid phase (raw material, ashes, char, fluidizing sand…) to define the mineral structure of each solid and their interaction during gasification of previous experiments. In addition, along with chemometric, you will have to design a program to handle all the data in a comprehensive way and to compare with already published data. To investigate possible mechanisms, you will have to lead an experimental campaign to study the volatilization of some targeted compounds. A continuous fluidized bed of several kilograms per hour will be used for the experimental campaign. Due to the size of the gasifier the number of experiments is limited. You then will have to set an experimental design to study the effect of experimental conditions and proportion of mixed waste of different compositions on the behavior of inorganic compounds. This task will be done in collaboration with members of the group. You will have to analyze all those new data and assays for establishing complete mass balance and mechanisms of interactions who could optimize inorganic capture in the solid stream.

    III. Profile required

    - An autonomous person with a strong sense of initiative
    - PhD in Process Engineering/Geology/Analytical Chemistry with skills in analytical works
    - Skills for data processing and chemiometric
    - Skills for solid characterization techniques
    - Writing reports and scientific publications.
    - Fluent French or fluent English
    As a manager, you’ll have to supervise interns and PhD students. Presentation of results at international conferences are welcome.

    IV. Duration : 18 months


    V. Localization and applications

    The laboratory is based in Aix en Provence, southern France. Travel in Stains, closed to Paris is to be expected at least once a month and for experimental assays on the fluidized bed.
    To apply, please send a resume and a cover letter to jean-henry.ferrasse@univ-amu.fr and
    Maxime.HERVY@engie.com.

  • New strategies to manage inorganic compounds in efficient steam waste gasification

    I. Context

    The position is in the frame of a national work program funded by the French National Research Agency. Consortium is made up of an academic laboratory (M2P2, Aix-Marseille Université) and ENGIE Lab CRIGEN (Centre de Recherche et Innovation Gaz et Energies Nouvelles), the ENGIE Group's center for research and operational expertise dedicated to gas, new energies and emerging technologies. The aim of the TIGRE project is to develop effective methods for full-scale modelling of the behavior of inorganic compounds in gasification reactors, considering the hydrodynamics of the system, heat transfer and the chemical nature of the various phases. You will be in charge to lead experimental work on a continuous gasifier. You will be integrated in a multidisciplinary team of experts in the field of gasification.

    II. Scientific issues

    The thermal gasification of waste represents a promising avenue for sustainable energy production and waste valorization. However, the formation of unwanted by-products coming from the inorganics elements originally present in feedstock constitutes a significant hurdle for process design and optimization. Addressing these scientific bottlenecks requires a combination of experimental research and advanced modeling techniques to enhance gasification efficiency and improve the quality of the resulting syngas. It is in this context that an experimental setup was developed to study the performance of a bubbling fluidized bed at low fluidization velocity. The experimental setup is a continuous pilot of some kg/hours with gas cleaning and sampling facilities (gas and solids) allowing gasification to be performed under a vast set of atmospheres. This experimental procedure provides complete temperature, gas composition and flow rate data for balance and efficiency calculation. Experimental tests and associated analyses are conducted to establish possible synergy between different feedstocks to expand the possible applicable feedstocks. The final objective is to develop a comprehensive modeling of inorganics behavior.
    The innovation of this work is then the application of different feedstock management strategies and
     controlled operating conditions and the consequence of those strategies on the resulting outflows of the process. In the first six months, you ‘ll work on several biomass and waste such as received to collect data and trained on the experimental pilot by exploring a range of operating conditions. The study of the physico-chemical interactions of raw materials with the fluidizing medium and the gasification atmosphere is a key point for this period. In a second time, in collaboration with the team, you’ll contribute to the design of a dedicated experimental plan and tests specifications to optimize inorganics recovery. The team is composed of 10 researchers. Among them you will have to specifically work daily with two PhD students.
    You may contribute to the development and comparison of gas sampling and analysis methods. Depending on experimental results, you may also contribute to the Improvement of the experimental pilot design. The project fits perfectly with the need to reduce dependence on fossil fuels and thus to the decrease of the environmental footprint of energy sector which is of major importance to meet the objectives of the European Union.

    III. Profile required

    - An autonomous person with a strong sense of initiative
    - PhD in Process Engineering with skills in experimental works on thermal processing
    - Skills Data processing and analysis
    - Skills for kinetic modeling
    - Writing reports and scientific publications.
    As a manager, you’ll have to supervise interns and PhD students. Presentation of results at international conferences are welcome.

    IV. Duration : 18 months


    V. Localization and applications

    You will be based in Stains closed to Paris, easily accessible from Paris center by public transportation. A monthly travel to Aix-en-Provence (southern France) for discussions is also to be planned.

    To apply, please send a resume and a cover letter to jean-henry.ferrasse@univ-amu.fr and Maxime.HERVY@engie.com.
  • ALE multi-fluid methods

    The mathematical and numerical modelling of multi-phase flows is never ending challenge for the academia (astrophysics, geophysics, meteorology, etc.) and industry (combustion, nuclear, health etc.). This modelling often involves dispersed multiple phases (liquid, gas, solid, and their combinations) and/or components (individual particles, droplets, bubbles, etc.). The extreme complexity and variety of mixed phases interactions, such as pressure gradients, flow speeds, material properties often limits multi-phase oriented research to simplified or ideal cases while numerous importance physical phenomena have to be addressed, even if in approximate ways, such as bubbles and slugs in pipes, nuclear reactor safety, cavitation, dust combustion and explosions and many more. 

    One of the most used approaches to describe such flows is multiphase or multi-fluid modelling based on a time, space or ensemble phase-conditioning average. A large variety of models exists based on the phases characteristics, geometries of dispersion, flow regimes, dissipation strategies, source terms, boundary conditions etc. However, all multifluid models are reduced to Euler-like fluid equations for mass, momentum and energy involving transport and pressure terms only when the dissipation effects are neglected. This is referred to as a ”backbone model”.
    Apart of the model choice, the numerical discretization of multi-fluid equations is a constant challenge due to variety of reasons: (i) the pressure couplings often cause the non-conservative form of equations, (ii) strong contrast of fluid characteristics yields to the presence of stiff terms, (iii) possible ellipticity of the system for certain flows (with subsonic inter-fluid drift velocities, for instance), (iv) the loss of the thermodynamic consistency resulted by pressure calculations inconsistency. Thus, an appropriate numerical scheme is required in order to address these difficulties. To this extend, a novel and efficient multi-fluid numerical scheme for discretizing the ”backbone” equations over a moving grid (ALE or Arbitrary Lagrangian–Eulerian) has been developed through a “Geometry, Energy, and Entropy Compatible” mimicking procedure (GEEC) [1–4]. Starting from the discretized density fields, energy fields, and transport operators, the procedure yields the discrete evolution equations in a practically univocal way. With arbitrarily moving grids, number of fluids, contrasts of volume fractions and equations of state, the resulting scheme is fully conservative in masses, momentum, and energy, preserves isentropic behaviour to the scheme order, and ensures per-fluid thermodynamic consistency. Noticeably, optimal isentropic behaviour is obtained thanks to a non-standard downwind form of pressure gradient. This has been validated in an ”in-house” developped 1D/2D code on a classic set of academic validation problems.

    This postdoctoral position will be dedicated to the extension of the previously developed work/code to 3D C++ multi-fluid parallelised solver in particular by addressing the following features:
    • introduction of turbulent energies under the constraint of pressure equalities;
    • introduction of dissipative terms and collision terms in accordance with mass transfer terms and adjustable pseudo-viscosities;
    • introduction of explicit estimates of implicit pressure with prediction-correction of transport and pseudo viscosity per fluid;
    • introduction of added masses under the constraint of pressures equality;
    • concept validation of all above in 3D parallelised code.

    The candidate will be working in a team of other members of the project in M2P2 including the collaboration with CEA researchers and engineers.

    How to apply
    Email to Pierre Boivin and Ksénia Kozhanova (firstname.lastname@univ-amu.fr)
    - Detailed CV and cover letter,
    - Transcripts (PhD students), PhD defense report (if applicable), a selection of 1-2 relevant research articles.
    - References
    - Preferred topic.

    References
    [1] Thibaud Vazquez-Gonzalez; Schémas numériques mimétiques et conservatifs pour la simulation d’écoulements multiphasiques compressibles; Université Paris–Saclay, Ph.D. thesis 2016SACLC051 (2016)
    [2] Thibaud Vazquez-Gonzalez, Antoine Llor, Christophe Fochesato; A mimetic numerical scheme for multi-fluid flows with thermodynamic and geometric compatibility on an arbitrarily moving grid; European Journal of Mechanics / B Fluids 65, 494–514 (2017).
    [3] Thibaud Vazquez-Gonzalez, Antoine Llor, Christophe Fochesato; A mimetic numerical scheme for multi-fluid flows with thermodynamic and geometric compatibility on an arbitrarily moving grid; International Journal of Multiphase Flow 132, 103324 (2020).
    [4] Eric Heulhard de Montigny, Antoine Llor; Taming the “stiff stiffness” of pressure work and equilibration in numerical schemes for compressible multi-fluid flows; International Journal of Multiphase Flow 153, 104078 (2022).

2024

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2023

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2022

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2021

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2020

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2019

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2018

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2017

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2016

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