Reference : UPR3346-NADMAA-079
Nombre de Postes : 1
Workplace : FUTUROSCOPE
Date of publication : Friday, January 13, 2023
Type of Contract : FTC Scientist
Contract Period : 3 months
Expected date of employment : 1 March 2023
Proportion of work : Full time
Remuneration : Between 2805 € et 3963 € gross monthly according to experience
Desired level of education : 5-year university degree
Experience required : Indifferent
At CNRS, on the Futuroscope site, the Pprime Institute is recruiting a researcher will participate in the research activities of the Triboelectrostatics team relating to the contract of the PPRIME Institute with GRANUPLAST company on improvement of a method for the triboelectrostatic separation of PE and PP pellets contained in certain mixtures from plastics recycling lines.
The collaboration contract between the two establishments follows the service contract carried out by the Triboelectrostatics team of the PPRIME Institute on behalf of the GRANUPLAST company on the Jassans-Riottier site. After a diagnosis of the weaknesses of the current electrostatic separation line and the formulation of the first recommendations to achieve the operation of the installation, GRANUPLAST and the Triboelectrostatic team wish to continue their partnership to improve the performance of the installation. On the one hand, it is a question of proposing the necessary modifications to improve the existing one in the tribocharging module and in the electrostatic separation module. Measurements and samples will be taken on the GRANUPLAST site and experimental plans will be conducted in Angoulême to determine the optimal operating parameters for the current installation. And on the other hand, to evaluate the interest of preloading the flakes upstream of the triboloader in the conveying system between the exit of the centrifugal dryer and the entrance of the triboloader. After GRANUPLAST has carried out the various proposed modifications, electrical charge measurements at several points on the line will be carried out to assess the performance of the installation.
* First step: proposal of the necessary modifications aimed at improving the performance of the current triboelectrostatic separation process: March 1st, 2023 - April 30th, 2023.
Preliminary tests will be carried out on the industrial installation to determine the minimum and maximum values of the inlet flow rate of the mixture in the tribocharger, the speed of rotation and the inclination of the tribocharger, the inclination and the values of the high voltage of the electrodes in order to have the limits to carry out several plans of experiments.
For each point of the experimental plans, measurements and samples will be taken on the industrial installation to evaluate the efficiency of the separation (the quantities of products obtained and their purities):
- measure the masses introduced in a unit of time (one hour) into the installation and the quantities of flakes recovered in the 11 compartments of the collector;
- recover samples of flakes collected in each of the 11 bins, measure their electrical charge using a Faraday cage connected to an electrometer, as well as their mass, to then calculate the electrical charge/mass ratio (the high values of this ratio, typically greater than 4 nC/g guarantee the quality of the separation);
- also take samples at the outlet of the funnel containing the mixture to be separated, at the outlet of the rotating tribocharger and at the outlet of the oscillating chute, and measure for each the electric charge/mass ratio;
- for each of the samples, after carrying out the electrical charge and mass measurements indicated in the previous paragraphs, evaluate the percentages of PP and HDPE by scanning them with the SIROPAD.
The implementation of experimental plans and the analysis and interpretation of this data in Angouleme will make it possible to determine the optimal operating point of the industrial installation. Mathematical models of the purities of the separations according to the operating parameters will be established. Tests will be conducted on the industrial installation to experimentally confirm the optimum operating point.
*Second Step 2: pre-study of the interest of preloading the chaff upstream of the tribocharger May 1st, 2023 – May 31st, 2023.
In situ analysis of the material conveying system between the outlet of the centrifugal dryer and the inlet of the tribocharger will determine whether it is possible to take advantage of this space to preload the mixture to be separated. The triboelectric charge at the input of the tribocharger will be evaluated by measuring the electric charges directly by a Keitheley electrometer, connected to a specially constructed Faraday cage. These measurements at different points of the line at the optimal operating point determined during step one will allow to evaluate the interest or not of having a preloading system.
The results obtained during the improvement phase and the pre-study of a preloading system will allow us to define the milestones of a possible second collaboration to modify the current system more structurally.
The candidate must have the following skills:
- High voltage engineering
- Instrumentation for measuring electrical quantities (potential, charge)
- Design of experiments methodology
- Data acquisition & analysis techniques
- Writing technical and scientific reports
The Electro-Fluido-Dynamics team has internationally recognized skills in the experimental and numerical modeling of physical phenomena associated with the movements of charged or polarized particles in a fluid in the presence of an electric field. This ranges from electrostatic precipitation at the scale of nanometer particles to electrostatic separation of granules at the millimeter scale, including electrostatic manipulation of powders and powdery materials at the micrometer scale. The investigation approach is mainly experimental, but it is supported by a growing activity of numerical and analytical modelling. The most important part of this team's activities concerns the research and development of a range of triboelectric chargers (rotating cylinder, fluidized bed, vibration) and electrostatic separators (drum, metal strip, two-disc electrodes) for the recycling of granular materials from waste electrical and electronic equipment. These industrial or laboratory facilities are the result of strong industrial partnerships with the CITF company (two CIFRE theses), manufacturer of special machines, Michelin, APR2 and Environnement Recycling, recycling specialists, as well as university collaborations (PHC – TASSILI and BRANCUSI, ERASMUS) with higher education institutions in Algeria (Sidi-Bel-Abbes, Oran, Guelma, Constantine) or Romania (Cluj-Napoca, Bucharest, Timisoara).
Constraints and risks
Short term travels in France are to be expected.
An extension of the contract is envisaged depending on the results obtained.
We talk about it on Twitter!