Decoupled approach to the modeling of contaminants removal from recycled paper - Archive ouverte HAL Accéder directement au contenu
Communication Dans Un Congrès Année : 2005

Decoupled approach to the modeling of contaminants removal from recycled paper

Résumé

The use of waste paper by paper industry has increased in recent two decades to the level compared to the use of virgin fibres. In the meantime the use of pressure sensitive adhesive (PSA) products (labels, stickers, tapes etc.) has become more and more popular due to their important performance benefits they offer to the consumers. Unfortunately even very small content of PSA material may dramatically reduce the paper quality so the removal of PSA particles (the so-called "stickies") has become the most important and most challenging part of paper recycling process. Pressure screening is the most efficient method used for mechanical separation of paper pulp impurities during recycling process. It is aimed at removal of pulp contaminants, which are of relatively big size when compared to paper fibres (diameter of 30m). The removal of PSA particles from the paper pulp is carried out with the use of the screening mill, where the flow (water suspension of fibres and contaminants) is enforced to pass the fine slots (100-200)m wide. The screening surface should let the fibres to pass while to reject the contaminants. The experimental practice indicates, however, that soft and visco-elastic PSA particles are able to pass the screen slots even if they are 3-4 times larger than the slot width. The paper presents the numerical modelling of the separation process aimed at the increased rejection efficiency. The simulation was split into two steps carried out with the use of two different tools, i.e. CFD code Fluent and ANSYS for structural mechanics analysis. During the first step the flow was resolved in the vicinity of the screening surface by employing one-phase flow model. Such an assumption could be made taking advantage of low mass content (not exceeding 3%) of discrete phase. The CFD computation provided the pressure distribution which could be then applied during the second simulation step to load the particle, assumed to be in rest at the inlet to the screen slot. The simulation performed with the use of ANSYS allowed to study the process of deformation and possible extrusion into the slot as a function of flow kinematics, screen geometry as well as PSA particle size and material properties. The results of the simulation provided the necessary insight into the complex phenomenon of the screening process and allowed to identify the parameters promoting the increased removal efficiency. The recommendations were defined for the industry on how the screening machinery (geometry and running parameters) and PSA materials could be modified in order to optimise the recycling process.
2005_06_02_Dresden.pdf (1.82 Mo) Télécharger le fichier
Origine : Fichiers produits par l'(les) auteur(s)

Dates et versions

hal-00205057 , version 1 (07-02-2020)

Identifiants

  • HAL Id : hal-00205057 , version 1

Citer

Dariusz Asendrych, Michel Favre-Marinet, François Julien Saint Amand. Decoupled approach to the modeling of contaminants removal from recycled paper. Third Joint Workshop on Multi-Phase Flows: simulation, experiment and application, May 2005, Rossendorf, Germany. ⟨hal-00205057⟩
61 Consultations
6 Téléchargements

Partager

Gmail Facebook X LinkedIn More