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

PhD : selection by topics

Technological challenges >> Green and decarbonated energy incl. bioprocesses and waste valorization
10 proposition(s).

Porous structures of hydrogenated nanodiamonds for CO2 transformation in exploitable products

Département Métrologie Instrumentation et Information (LIST)

Laboratoire Capteurs Diamants

01-10-2020

SL-DRT-20-0571

Green and decarbonated energy incl. bioprocesses and waste valorization (.pdf)

Since its identification as a source of solvated electrons usable for photocatalysis, hydrogenated bulk diamond is actively investigated for CO2 reduction. This behaviour is conferred by the C-H dipoles present at the surface that favor the electron emission to the interface with surrounding media. Moreover, its electronic structure (negative electron affinity) allows the emission of photoelectrons, able to initiate the CO2 reduction at one electron or to form solvated electrons. Hydrogenated nanodiamonds behave a similar electronic structure as we demonstrated few years ago. This PhD aims first to elaborate porous materials using diamond nanoparticles via innovative and scalable technics to allow a tunable and efficient use for CO2 reduction. Performances for CO2 reduction will be then evaluated while mechanisms involved in the production of reducing species under illumination will be investigated via a more fundamental approach. The first barrier concerns the elaboration of nanocomposite porous matrix fabricated from hydrogenated diamond particles for photo(electro)catalysis. An original process (HIMAYALAN) developed at LEDNA, combining nanoparticles jets under vacuum to magnetron sputtering, will be used. Porous layers of nanoparticles embedded in another material (silica or amorphous carbon) will be fabricated exhibiting a very high porosity. A co-doping of such composites with metallic particles is also performed to improve the optical absorption performances. A proof of concept is currently under progress with the Bottom-up project CORAIL. The second obstacle corresponds to the boron doping of diamond particles (size 10 to 200 nm) which confers it an electrochemical activity. In that case, their catalytic efficiency can be enhanced applying a bias. Different synthesis routes are considered: from the milling of boron doped diamond films (commercial particles) to a more innovative and scalable approach based on the synthesis of core shell boron doped diamond. The former process patented at LCD will be developed during an ANR PRCE project starting in April 2020. The second aspect of this PhD concerns the evaluation of porous nanocomposite diamond layers for the CO2 reduction via photo(electro)catalysis. A dedicated set-up will be developed at LCD including a lamp and the ability to work under CO2 pressure. The crystalline structure and the properties of hydrogenated boron doped diamond particles will be investigated using SOLEIL Synchrotron facilities. Relations with their photocatalytic performances will allow to improve their efficiency. XPS studies on isolated particles will be achieved on PLEIADES beamline to extract the surface structure at the atomic level and the location of heteroatoms. Photo-ionisation and photo-fragmentation studies versus the wavelength of incident radiation will be performed on DESIRS beamline.

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Behavior of inorganic elements in supercritical water gasification

Département Thermique Biomasse et Hydrogène (LITEN)

Laboratoire de Conversion de ressources Carbonées par voie Hydrothermale

01-10-2020

SL-DRT-20-0649

geert.haarlemmer@cea.fr

Green and decarbonated energy incl. bioprocesses and waste valorization (.pdf)

To valorize very wet or even liquid carbon resources, a very promising process for energy valorization is the gasification in supercritical water that produces a synthesis gas (mixture of CH4, H2 and CO2). Gasification in supercritical water is based on phenomena related to water properties under high pressure and high temperature. Beyond its critical point (temperature 374 ° C and pressure 22.1 MPa), water becomes a very reactive medium and promotes gasification reactions. Among the resources targeted by this process, we can cite, for example, waste from the agri-food industry (fruit and brewer's grains ...), industrial effluents (black liquor), microalgae, digestates from anaerobic digestion, sewage sludge ... The development of gasification process in supercritical water is at the laboratory pilot scale. Research and development actions are still needed to reach the industrial scale. One of the main barriers is the management of pollutants in the resource such as H2S and the presence of inorganics. The aim of this thesis is to better understand the behavior of salts and pollutants in supercritical water conditions. With this knowledge, an evaluation of the different inorganic and pollutant management strategies is expected, either thermodynamically or chemically, and thus help the laboratory to propose design solutions for future supercritical water gasification pilots.

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Development of MOFs for the detection, adsorption and destruction of toxic gas

Département des Technologies des NanoMatériaux (LITEN)

Laboratoire des Eco-procédés et EnVironnement

01-09-2020

SL-DRT-20-0736

arthur.roussey@cea.fr

Green and decarbonated energy incl. bioprocesses and waste valorization (.pdf)

This PhD thesis focuses on the development of novels Metal Organic Frameworks (MOFs) for the adsorption and destruction of toxic chemicals such as H2S or organophosphorus based pesticides. MOFs are a class material with very high specific surface area composed of metallic ions or clusters coordinated with organic ligands. As a wide variety of metals and ligands can be used, innovative materials can be synthesized to obtain specific physical and chemical properties. During the thesis, using molecular engineering, the candidate will synthesize and/or functionalize MOFs to enhance their adsorption capacity and selectivity towards the target chemicals. Mechanistic studies of adsorption or chemisorption will be performed by adsorption capacities and selectivity measurement in conditions representatives of the applications. Materials structure and target/material interactions will be finely characterized using the wide range of available technics (XRD, XPS, FTIR, UV-Vis-NIR, solid-state NMR, ?). The integration of chromogenic ligand will also be investigated to allow direct colorimetric detection of the target chemicals.

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Optimization of a liquid hydrocarbon synthesis reactor from a biobased syngaz and a renewable hydrogen production

Département Thermique Biomasse et Hydrogène (LITEN)

Laboratoire Echangeurs et Réacteurs

01-10-2020

SL-DRT-20-0815

genevieve.geffraye@cea.fr

Green and decarbonated energy incl. bioprocesses and waste valorization (.pdf)

During the past 20 years, « Biomass-to-liquid » processes have considerably grown. They aim at producing a large range of fuels (gasoline, kerozene, diesel, marine diesel oil) by coupling a biomass gazéificationgasification into syngaz syngas unit (CO+CO2+H2 mixture) and a Fischer-Tropsch (FT) synthesis unit. Many demonstration pilots have been operated within Europe. Nevertheless, the low H/C ratio of bio-based syngazsyngas from gasification requires the recycling or even a discharge of a huge quantity of CO2 at the inlet of gaseificationgasification process, which implies complex separation and has a negative impact on the overall valorization of bio-based carbon. Moreover, the possibility to realiserealize, in the same reactor, the Reverse Water Gas Shift (RWGS) and Fischer-Tropsch (FT) reaction in the same reactor with potassium promoted iron supported catalysts has been proved (Riedel et al. 1999) and validated in the frame of a CEA project PhD thesis (Panzone, 2019). Therefore, this concept coupled with the production of hydrogen from renewable electricity opens new opportunities to better valorize the carbonaceous content of biomass. The focus of the PhD is based on the FT synthesis under dynamic regime. On the one hand, the catalytic synthesis will be realized performed with dynamic variations of inlet gases composition (various ratios of CO2, CO, H2, CH4 ?) and total syngas flow in a fixed bed reactor. On the other hand, a reactor model will be built (coupling kinetic, thermodynamic, heat and mass transfer ? with COMSOL software) in order to understand and define and understand physico-chemical effect of such dynamic variations.

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Recycling of fluorinated polymers contained in new technologies for energy (NTE)

Département des Technologies des NanoMatériaux (LITEN)

Laboratoire des Eco-procédés et EnVironnement

01-10-2019

SL-DRT-20-0825

emmanuel.billy@cea.fr

Green and decarbonated energy incl. bioprocesses and waste valorization (.pdf)

Fluoropolymers are today very widely used for their mechanical and chemical properties and their durability. Polymers are unavoidable in the field of NTEs such as proton exchange membrane fuel cells (Nafion membrane in PEMFCs), batteries (PVDF at electrodes), or photovoltaic panels (EVA at the glass cell interface). With the advent of carbon-free technologies, the issue of recycling has become central to bringing these technologies to market. Historically, recycling processes were designed for processing different technologies and large volumes. This has led to the establishment of pyrometallurgical processes (high temperature) that are robust, but destructive and non-selective. In a context constrained by strategic, legislative (recycling rate) and environmental issues, it is necessary to recycle "more" and "better". This thesis aims at finding new wet or dry ways for the treatment of fluorinated compounds. The use of ionic liquids for the solubilization of polymers will be a preferred route. Their intrinsic physicochemical properties (very low volatility and flammability) make them ideal candidates for overcoming safety and environmental issues. The thesis work will be divided into three parts. Firstly, a state of the art will be realized for the evaluation of conventional processes and media for the treatment of fluorinated compounds. The state of the art will be tightened on the fluorinated polymers used in the field of new technologies for energy (NTE). A second part will deal with the chemistry of polymers and solvents in which a polymer can be dissolved. A third part of a fundamental nature will aim at linking the macroscopic results to the structural evolutions of the polymers.

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Abatement of gaseous inorganic pollutant release in biomass and waste gasification

Département Thermique Biomasse et Hydrogène (LITEN)

Laboratoire de Conversion de ressources Carbonées par voie Sèche

01-10-2020

SL-DRT-20-0850

sylvie.valin@cea.fr

Green and decarbonated energy incl. bioprocesses and waste valorization (.pdf)

The objective of the thesis is to characterize the release of gaseous inorganic pollutants (H2S, COS, HCl, NaCl, KCl in particular) in biomass and waste gasification, and to propose and test in-situ methods to limit this release. These methods, based on chemical interactions between inorganic elements, will mainly consist in the use of additives or in implementation of resource blends. Gasification allows producing a synthesis gas which can be used in cogeneration (heat and electricity) or for the synthesis of liquid or gaseous fuel. However, inorganic volatile pollutants must be removed before the final application, because of environmental emission standards, as well as because of their corrosive nature (HCl, KCl, NaCl), or of their poisoning influence on catalysts used for synthesis (H2S). The proposed approach will consist in, firstly, performing thermodynamic simulations so as to understand the behavior of inorganic elements in gasification, and to define and interpret the experiments to be performed in the laboratory. Analytical experiments will be performed at laboratory and pilot scale, and will be associated with gas analyses and characterization of the residual ash (SEM, XRD). The obtained results will be used to better control the inorganic pollutant concentrations in synthesis gas as a function of the variability of the carbonaceous resources, and to precise the cleaning process before the final application.

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Optimization of the recycling of cathode materials for lithium-ion batteries by hydrometallurgical processes: study of the reactivity of transition metal oxides with ionic liquids.

Département des Technologies des NanoMatériaux (LITEN)

Laboratoire de Nanocaractérisation et Nanosécurité

01-09-2020

SL-DRT-20-0863

anass.benayad@cea.fr

Green and decarbonated energy incl. bioprocesses and waste valorization (.pdf)

The fast demand for electrical vehicle as well as the need to increase our capacity to store intermittent energy sources induce a strong demand for Li-ion batteries. Production is not only costly in terms of energy but also regarding pollution, which means that they must be recycled. Indeed, separately, the components can have a second life in new batteries. Thus reducing the dependency on the battery material considered critical and strategic by the European Union. Their treatment is imperative for the massive development of electric vehicles in France and Europe. The end of life of Li-ion batteries is a major industrial issue throughout the recycling chain. Recycling batteries, which are complex in composition (polymer, metals or plastics), is a technological and environmental challenge. Hydrometallurgical processes offer better prospects for reducing energy costs for the treatment of this type of waste and meeting the global demand for high-purity precursors for the synthesis of new electrode materials. However, many technological building blocks of recycling processes must be developed to meet the economic and environmental challenges of battery recycling. The use of ionic liquids, presents an alternative for their use in various process bricks to reduce the risks associated with conventional solvents. Due to their low saturation vapor pressure, they are non-flammable and non-volatile, reducing the risks associated with conventional media (aqueous and organic). However, the reactivity of the materials making up Li-ion batteries (cathode materials based on transition metal oxides, spectators, collectors, etc.) with ionic liquids is not well studied. The purpose of this thesis is to study the reactivity of anode and cathode materials based on transition oxide metals with respect to solvents based on ionic liquids by coupling physico-chemical and electrochemical characterization in post-mortem mode and operando. This coupling will provide solutions for the extraction of transition metals to reintegrate them into new applications for energy storage. The candidate must hold a master's degree in research (M2) or an engineering degree in materials science, physics or equivalent. A background in electrochemistry will be suitable He or she must be motivated to work in a multidisciplinary team. The candidate will be welcomed in the laboratories of the L2N and L2EV of the DTNM to carry out his internship work.

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Modeling of biomass torrefaction at pilot scale with data measured at small scale

Département Thermique Biomasse et Hydrogène (LITEN)

Laboratoire de Conversion de ressources Carbonées par voie Sèche

01-10-2020

SL-DRT-20-0866

Muriel.Marchand@cea.fr

Green and decarbonated energy incl. bioprocesses and waste valorization (.pdf)

Torrefaction is a thermal pretreatment applied to biomass, carried out under neutral atmosphere for several tens of minutes, at temperatures between 200 and 300°C. Once treated, the solid exhibits properties closer to those of coal (fossil), making it suitable to the same industrial facilities as this latter. Namely, torrefaction enhances the carbon content in the solid, thus increasing the interest of its thermochemical conversion to contribute to the closure of the carbon cycle. The biomass platform of CEA Grenoble has been equipped with a pilot-scale torrefaction oven (capacity: 150kg/h of wood). The results obtained in this pilot oven are always out of sync with the torrefaction data measured in the laboratory. Therefore, the validity of the change of scale for this process is questionable. The aim of this thesis is to improve the extrapolation at pilot scale of data measured with small analytical equipment. Three successive phd prepared in the laboratory, have led to a model representing the different chemical transformations of biomass during torrefaction. This model will be used in the proposed phd. This work will require to perform a lot of experimental investigations, in the laboratory (small scale) as well as to participate to torrefaction campaigns with the pilot.

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Intensification of carbon dioxide sequestration through microalgae photosynthesis

DPACA (CTReg)

Autre DPACA

01-10-2020

SL-DRT-20-0948

gatien.fleury@cea.fr

Green and decarbonated energy incl. bioprocesses and waste valorization (.pdf)

Numerous scientific studies, led in particular by IPCC, have shown that anthropogenic greenhouse gas emissions are responsible for global warming of Earth's atmosphere. Due to the tremendous volumes emitted worldwide annually (more than 30 billion metric tons), CO2 is considered to be one of the main contributors to global warming. Among the methods for sequestering CO2, photosynthesis is particularly attractive, since it makes it possible to create different products through to the capture of solar energy together with CO2. This PhD thesis will focus on the use of microalgae photosynthesis for CO2 sequestration. After a bibliography step which will allow the student to better understand the equilibria at stake and the corresponding equations, first part of the work will focus on the development of an analytical model allowing to simulate different operating conditions by a multidisciplinary approach (in particular fluid mechanics, chemistry and biology). After validation of this model on simple experiments made up with a strain of reference, an innovative culture device (photobioreactor) making it possible to intensify the mass transfers of a gas phase enriched in C02 towards microalgal biomass could be proposed, developed and tested.

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Capture and recovery of CO2 by electroreduction

Département des Technologies des NanoMatériaux (LITEN)

Laboratoire des Eco-procédés et EnVironnement

01-10-2020

SL-DRT-20-0955

vincent.faucheux@cea.fr

Green and decarbonated energy incl. bioprocesses and waste valorization (.pdf)

Electrochemical conversion of CO2 (from industry or directly from air) is a way to produce fuels or chemicals from intermittent electricity. In addition, micro-algae culture is a process that could replace petrochemicals, by producing biofuels while completing the anthropogenic carbon cycle. The combination of these two sectors in a new hybrid concept would improve the performance of microalgae production processes upstream of bioenergy applications. Indeed, the culture of micro-algae in the presence of light and an organic substrate formate based, produced by electrolysis of CO2 allows accelerated growth. Several challenges must be addressed to reach such technology with high-energy yields: catalytic in order to maximize the production of formate and integrative in order to maximize the yield of photo bioreactors by using the whole solar spectrum (by coupling photovoltaic generation of electricity and photosynthetic generation of biomass according to the absorbed wavelengths). The first objective of the thesis is to develop a catalytic system associated with an advantageous liquid media based on the use of ionic liquids whose CO2 absorption capacity is much greater than for water. Measurements will permit to establish material and energy balances by coupling the reduction of CO2 with the oxidation of water. Acquired knowledges will then be transferred to the cases of physiological fluids, compatible with the generation of formate and the production of lipids by micro algae. The second objective consists in improving the energy efficiency of biomass production within a high-yield photo bioreactor (PBR) which will use the whole solar spectrum, by coupling photovoltaic generation of electricity and photosynthetic generation of biomass. Semi-transparent photovoltaic systems that can be integrated into PBR and optically optimized to promote the production of electricity and the growth of micro-algae will be developed. As part of this thesis project, the goal is to develop an electrolyzer for the production of formate in physiological electrolyte which can be supplied by the above-mentioned photovoltaic panel.

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