The Laboratoire du Génie des Procédés Papetiers (LGP2) and the Laboratoire de Rhéologie et Procédés (LRP), are seeking candidates for a PhD on ultrasound assisted de-inking or bleaching processes of cellulose fibres.
The research problem deals with the use of ultrasound to increase mass transfer in liquid phase of reactive gases used in unit operations of paper processes. Beyond the transfer, the action of ultrasound on the reactivity of these gases and/or on the generation of oxidizing species within the liquid phase will also be investigated. Attention will also be paid on possible interactions between ultrasound and fibres. The objective is therefore the intensification of processes in the aim of improving the overall performances (effluent and fibre quality) while reducing the quantity of reagents used and the environmental impact of discharges.
Project outline
The main work package of the project will be:
- WP1: Bibliography on the subject with two main parts: (i) gas/liquid transfer and ultrasound and (ii) implementation of oxygen and ozone in paper processes.
- WP2: Characterization of gas/liquid contactors with and without ultrasound. Determination of volumic transfer coefficients and specific surface area of exchange by controlled model systems (e.g. oxygen in a sulphite solution) and of the solubility of ozone and oxygen in different waters (tap water, paper mill model water, different pH values, etc.) and for different operating conditions (e.g. flow rate) and ultrasonic wave emission (frequency, power).
- WP3: Determination of gas/liquid reaction regimes, for the self-decomposition of gases into water and for reactions with contaminants in paper process water. Reaction kinetics will be studied, and an approach based on adimensional numbers with integration of ultrasound characteristics will be considered.
- WP4: Incorporation of virgin and/or recovered cellulosic fibres in suspension at low consistency (1-3%) with and without ultrasound. The use of ultrasound coupled with the introduction of gas may be carried out upstream or in the reactor containing the fibres. The performances on the optical (whiteness, ...) and physical properties (tear resistance, ...) of the fibres and on the quality of the effluents (COD, ...) will be characterised.
- WP5: Valorisation of the results in the form of articles, conference proceedings and thesis manuscript.
Location and practical aspects
The PhD student will be supervised by Professors Marc Aurousseau (Grenoble INP / LGP2) and Nicolas Gondrexon (UGA / LRP). The research work will therefore be carried out within the framework of a collaboration between two laboratories, LGP2 and LRP, located on the university campus of Saint-Martin d'Hères near Grenoble, 150 metres from each other and providing complementary expertise and experimental equipment (reactors, ultrasound devices, characterisation of gaseous, liquid and solid phases, etc.). The site's shared platform resources could also be used (high-speed camera for example) and collaborations with other French laboratories are envisaged.
Profile
The candidate recruited must have a Master 2 or engineering degree in Process Engineering. Experience in gas/liquid transfer and/or in the implementation of ultrasonic waves would be appreciated, as well knowledge of cellulosic fibres. The expected skills are: taste for the research approach, experimenter qualities, team work on a multidisciplinary subject, autonomy, very good level in English, writing. For foreign student, a B2 level in French will be appreciated. He/she will be enrolled in the I-MEP2 doctoral school.
Salary
As part of a doctoral contract with Grenoble INP the net salary will be of 1400 € month. Possibility to work shifts or the RES label allowing an additional income.
Application
Please, send your CV, transcripts and cover letter with motivations by e-mail to Marc Aurousseau and Nicolas Gondrexon.
Deadline for application: May 20, 2020.
