General information
Organisation
The French Alternative Energies and Atomic Energy Commission (CEA) is a key player in research, development and innovation in four main areas :
• defence and security,
• nuclear energy (fission and fusion),
• technological research for industry,
• fundamental research in the physical sciences and life sciences.
Drawing on its widely acknowledged expertise, and thanks to its 16000 technicians, engineers, researchers and staff, the CEA actively participates in collaborative projects with a large number of academic and industrial partners.
The CEA is established in ten centers spread throughout France
Reference
SL-DES-24-0604
Thesis topic details
Category
Technological challenges
Thesis topics
Study of the thermoconversion and de-polymerization mechanisms of plastic wastes in supercritical water conditions
Contract
Thèse
Job description
The waste valorization is a hot topic that has attracted great interest in the Circular Carbon Economy. Substantial efforts have been devoted to strengthening sustainable processes in recent years. These are based on the development of systems to improve carbon circularity (material and energy recycling).Global production of plastics doubled from 230 million tons in 2000 to 460 million tons in 2019. This exponential production/consumption has significant consequences on the environment. Despite the existence of recycling methods, only 9% of global plastic production is currently recycled, and the remaining quantity (not valorized) represents a real source of pollution [1].
Mixtures of different types of plastics make sorting stages difficult, which represents the main disadvantage for material recycling systems. An interesting application recently reported in the literature is the use of the hydrothermal gasification process to treat waste (and mixtures of difficult-to-sort) plastics to produce a gas rich in CH4 and H2 [2]. Hydrothermal gasification (HTG) is a thermochemical process which employs the supercritical conditions of water (T > 374 ° C, P > 221 bar), in order to convert the organic carbon contained in the wet feedstock into a gaseous phase (which contains CH4, H2, CO and CO2, mainly). In addition, the flexibility of the process also allows the study of de-polymerization of these wastes in conditions close to the critical point of water, which facilitates the production of chemical intermediates (and their reuse) in the chemical industry.
Thus, the understanding of the conversion mechanisms of different types of plastics (and their mixtures) seems essential to valorize these wastes. However, the identification of reaction pathways is still a major scientific obstacle. The objective of the thesis is the study of the reaction mechanisms of transformation of model plastics (and their mixtures) in supercritical water conditions. Understanding the phenomena will lead to the optimization of the HTG process (with and without catalysts) to facilitate the production of a gas rich in CH4/H2 and the production of intermediates for the chemical industry. The focus of this PhD work will involve: i) the study of thermo-conversion and de-polymerization of plastics; ii) the study of the behavior of catalysts in the supercritical water environment (activation/deactivation); iii) the study of selectivity towards the production of a gas containing CH4/H2 and the production of chemical intermediates.
University / doctoral school
Chimie, Procédés, Environnement (Chimie Lyon)
Université de Lyon
Thesis topic location
Site
Grenoble
Requester
Position start date
01/10/2024
Person to be contacted by the applicant
DEMEY CEDENO Hary hary.demeycedeno@cea.fr
CEA
DRT/DTCH//LRP
Commissariat à l’énergie atomique et aux énergies alternatives
17 rue des martyrs, F-38054 Grenoble Cedex
04 38 78 56 50
Tutor / Responsible thesis director
FONGARLAND Pascal pfo@lgpc.cpe.fr
CPE Lyon/CNRS
CP2M
CPE
CP2M
Domaine Scientifique de la Doua
Bâtiment Hubert Curien
43, boulevard du 11 Novembre 1918
BP 82077 - 69616 Villeurbanne Cedex
0472431757
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