Scientific direction Development of key enabling technologies
Transfer of knowledge to industry

PhD : selection by topics

Technological challenges >> Additive manufacturing, new routes for saving materials
3 proposition(s).

See all positions [+]

Architectured materials for heat exchangers applied to the energy transition

Département des Technologies des NanoMatériaux (LITEN)

Laboratoire de Modélisation et Matériaux pour la Métallurgie

01-09-2021

SL-DRT-21-0731

guilhem.roux@cea.fr

Additive manufacturing, new routes for saving materials (.pdf)

This project concerns the eco-innovation of multi-scale 3D printed architectured structures for innovative reactor-exchangers. The ambition is to improve the performance in terms of kinetics, stability and selectivity of chemical reactions used in the field of hydrogen production or recovery. The structures developed will be optimized by thermal simulation in order to maximize their efficiency by taking advantage of additive manufacturing geometric possibilities. The targeted applications are the production of synthesis gas by catalytic processes: CO2 methanation [1], Fischer-Tropsch reactions, LOHC technology or even the decomposition of NH3. As part of the thesis, it is proposed that one of these applications be treated as a priority. Scientific challenges considered during this thesis will be the development of reliable thermo-fluidic simulation tools at the scale of elementary cells (Representative Elementary Volume) by coupling thermal simulation for the solid part and lattice Boltzmann method for the fluid part. Using an upscaling strategy, modeling at the representative scale of the useful reactors sections (mesoscopic calculation) as well as full scale reactors will be carried out using finite element method (Comsol). A screening of elementary structures will be carried out beforehand in order to identify the most suitable structures for each application, using a design tool for elementary structures. Final expectations will feed several circular economy action levers to reduce economic (competitiveness with more compact, more selective exchangers) and environmental impacts (low in energy and material): increase the process efficiency, increase catalyst lifetimes and decrease in ecological impact through a comparative environmental impact analysis (LCA). This thesis will be a collaboration between DAM/Le Ripault and DRT /Liten. The first year of the thesis will be conducted at Le Ripault (Tours) and the last two years in Grenoble.

Download the offer (.zip)

Multi-functional material for catalytic hydrogenation of CO2 to methanol and dimethyl-ether

Département Thermique Conversion et Hydrogène (LITEN)

Laboratoire réacteurs et procédés

01-09-2021

SL-DRT-21-0750

albin.chaise@cea.fr

Additive manufacturing, new routes for saving materials (.pdf)

Hydrogen production by water electrolysis coupled to catalytic hydrogenation of CO2 into hydrocarbon or oxygenates of high energetic Density (methanol, DME) can contribute to the decarbonation of transportations (sea, air transportation) and provide products for a sustainable chemistry. However, these reactions are limited thermodynamically. The current PhD proposal aims at developing a coupled system of catalytic reaction (CuZnO/Al2O3 and zeolites), de-hydratation by separation and/or adsorption of water (ZSM5 and LTA zeolites) for direct synthesis of methanol and DME form CO2. Non-critical and recyclable material (Cu, Zn, Al) and low environmental footprint processes (supercritical CO2, hydrothermal, micro-waves) or bio-templates. One essential goal will be to obtain 3D oriented zeolites with limited defaults, first on planes surfaces then on 3D structures (ceramics or metal). The intrinsic material performances will first be tested on samples. Then the material will be integrated in a 3D reactor with catalysts at the scale of a few L/min of reactants.

Download the offer (.zip)

Numerical simulation for processing powder bed additive manufacturing

Département des Technologies des NanoMatériaux (LITEN)

Laboratoire de Modélisation et Matériaux pour la Métallurgie

01-09-2021

SL-DRT-21-0752

guilhem.roux@cea.fr

Additive manufacturing, new routes for saving materials (.pdf)

The project concerns the study of powder spreading in the context of powder bed additive manufacturing processes, in particular L-PBF (Laser-, Powder Bed Fusion) and MBJ (Metal Binder Jetting) processes. The ambition is to give CEA a reliable simulation tool making it possible to reproduce what happens during this process key stage, when the real powder bed (intended to be melted or agglomerated depending on the technologies) is spread out. This project will be fed by results from a dedicated instrumented spreading set-up as well as by elementary experiments. The simulation will be based on DEM method (discrete element method, [1]), benefiting from developments acquired by the partners (DES/IRESNE) in powder transitics and from first developments in progress at DRT / LITEN. The particle interaction behavior models will be fed by a wide range of real characterizations under elementary flow conditions. The models will then be initially compared on these elementary tests, then ultimately on real full-scale results obtained on the specific DRT/LITEN spreading set-up. Today, several works are carried out on this subject ([2] [3] [4] [5]), but they take into account idealized, spherical and mainly monodisperse powders. The originality of this work compared to the state of the art is to investigate beyond the behavior of model powders by taking into account real morpho-physico-chemical state of various powders (surface roughness, sphericity, charge electrostatic effect, effect of humidity, effect of oxidation state,?) of powders. In particular, one objective will be to understand the mechanisms powders ageing and their consequence on flowability, a real industrial issue. In addition, this study will show the consequences on the flowability of composite powders developed at CEA ([6] [7]). This thesis will be a collaboration between DES/IRESNE and DRT/LITEN.

Download the offer (.zip)

See all positions