24 May 2024
Job Information
- Organisation/Company
CNRS- Department
Laboratoire Réactions et Génie des Procédés- Research Field
Chemistry
Physics
Technology- Researcher Profile
First Stage Researcher (R1)- Country
France- Application Deadline
13 Jun 2024 - 23:59 (UTC)- Type of Contract
Temporary- Job Status
Full-time- Hours Per Week
35- Offer Starting Date
1 Oct 2024- Is the job funded through the EU Research Framework Programme?
HE- Is the Job related to staff position within a Research Infrastructure?
No
Offer Description
This thesis will take place at the University of Lorraine (UL) at the Reaction and Process Engineering Laboratory (LRGP – UMR CNRS 7274) in Nancy (54000, France).
The subject of this thesis concerns the precipitation step of lignin present in black liquors assisted by CO2 coupled with a conversion by pyrolysis to produce molecules of interest (phenols). One of the technological issue associated with the lignin pyrolysis is the agglomeration and clogging of the reactors. Indeed, during pyrolysis, the lignins form a sticky reactive intermediate material converted into char and liquid products (bio-oils) generated in the form of aerosols or vapors condensed in pyrolysis units. The scientific challenge of lignin pyrolysis is to control the composition of the liquids (monomers, suitable oligomers) and the structure of the char (biochar) produced. The objectives of this doctorate are:
- ) to optimize the lignin precipitation step from black liquors from the DREAM project in a semi-continuous reactor: study of the effect of temperature, pressure, pH. Characterize the products obtained (GC, LC, NMR, IR, thermal analyses, etc.) -) study the pyrolysis of lignins obtained in a fluidized bed reactor (and others): flow rates, temperatures, fluidization behavior of the bed depending on the lignins. Hydrodynamic study by in-situ visualization of the reactor. Characterization of the products obtained (GC, LC, NMR, IR, thermal analyses, etc.).
The development of alternative biosourced processes is one of the major challenges of a sustainable economy concerned with preserving the environment. In pulp mills (from wood raw material to pulp), cellulose (fibers) are separated from lignin, hemicellulose and inorganic molecules. Around 100 million tonnes of wood are recovered for a production of 85 million tonnes of pulp in Europe (2022 data, including the use of recycled paper – 185 million tonnes worldwide, 7 million tonnes in France). The most used process is the Kraft process (90% of world production) which involves the treatment (digestion) of wood fibers in an aqueous solution called white liquor containing sodium hydroxide and sodium sulphide. Thus, black liquors (BL) are a waste stream from the Kraft process obtained after delignification of the biomass (wood) during the digestion operation. With more than 500 million tonnes/year of BL generated worldwide, the treatment and recovery of BL is an important industrial and environmental issue.
Currently, BLs are concentrated by multiple evaporator systems and are then burned to regenerate inorganic materials and recover heat necessary for the Kraft process. Since evaporation systems have a fixed capacity, they currently constitute a bottleneck compared to a potential increase in production within factories using the Kraft process. In fact, these factories cannot produce more paper pulp without taking the risk of not being able to regenerate all of the by-products formed. Thus, the exploration of alternative processes for a portion of the BL produced could benefit pulp mills by reducing CO2 emissions and producing a wide variety of biosourced compounds: lignin, phenolic compounds, aromatics, acids. In the medium term, these pulp mills have the potential to transform into integrated forest biorefineries, producing a wide range of bio-sourced products. Numerous valorization strategies have been explored to extract/separate the compounds of interest (membrane filtration, liquid-liquid extraction, decantation, distillation) or to transform BL directly into energy (gasification, pyrolysis, hydrothermal treatment). It is in this context of need for development that the EIC Pathfinder DREAM project (processing complex matrices: Description, REAction-separation, Modelling) financed by the European Council takes place. The DREAM project aims to contribute to major scientific advances in the study of complex matrices (black liquor as a case study) with potentially future “on-site” industrial development. Several separation/extraction routes are studied in the DREAM project (membrane separation, precipitation, membrane filtration) followed by several transformation/purification routes (Reactive distillation, thermochemical processes).
Requirements
- Research Field
- Chemistry
- Education Level
- PhD or equivalent
- Research Field
- Physics
- Education Level
- PhD or equivalent
- Research Field
- Technology
- Education Level
- PhD or equivalent
- Languages
- FRENCH
- Level
- Basic
- Research Field
- Chemistry
- Years of Research Experience
- None
- Research Field
- Physics
- Years of Research Experience
- None
- Research Field
- Technology
- Years of Research Experience
- None
Additional Information
Additional comments
https://cordis.europa.eu/project/id/101130523
- Website for additional job details
https://emploi.cnrs.fr/Offres/Doctorant/UMR7274-YANLEB-004/Default.aspx
Work Location(s)
- Number of offers available
- 1
- Company/Institute
- Laboratoire Réactions et Génie des Procédés
- Country
- France
- City
- NANCY
- Geofield
Where to apply
- Website
https://emploi.cnrs.fr/Candidat/Offre/UMR7274-YANLEB-004/Candidater.aspx
Contact
- City
NANCY- Website
http://lrgp-nancy.cnrs.fr
STATUS: EXPIRED