Pulp fibers can be spouted in a conical vessel if the inlet Reynolds number is above a critical value which varies linearly with mass of pulp in the vessel. Continuous pulp spouting is also feasible in a wedge-like vessel within certain limits of flow rate and inlet pulp consistency. Spouting hydrodynamics and particle separation behavior in both vessels were investigated for pulp fibers and recycled pulp suspensions. / The minimum spouting velocity (MSV), spouting stability and the pressure drop-flow rate relationship were determined for liquid spouting of pulp fibers and of rigid particles. Liquid spouting of rigid particles is similar to gaseous spouting; pulp spouting is different. The liquid flow field in a conical spouted bed of pulp fibers is of a jet expansion type. A model for predicting the MSV for spouting pulp fibers was developed based on visual observation of the transition of the jet flow patterns in the conical vessel. / Small particles including both ink and pulp fines can be elutriated from a spouted bed of a recycled pulp suspension, with little fiber loss, in both semi-batch and continuous modes using conical and wedge-like vessels, respectively. Both processes were studied using on-line measurement of the exit particle concentration. / For the semi-batch process, the first order elutriation coefficient increased with the flow rate, but was about the same for all pulps. Based on the analysis of the flow field around a porous spherical particle in a shear flow, an elutriation model was developed for fine particle removal from a suspension of porous coarse particles. For the continuous operation, the particle separation mechanism and the fractional particle removal were investigated. Separation occurs by excluding fibers from the top stream, while fines are split according to the ratio of top to bottom flow rates.
| Identifer | oai:union.ndltd.org:LACETR/oai:collectionscanada.gc.ca:QMM.28409 |
| Date | January 1994 |
| Creators | Al-Jabari, Maher |
| Contributors | Weber, M. E. (advisor), Ven, T. G. M. van de (advisor) |
| Publisher | McGill University |
| Source Sets | Library and Archives Canada ETDs Repository / Centre d'archives des thèses électroniques de Bibliothèque et Archives Canada |
| Language | English |
| Detected Language | English |
| Type | Electronic Thesis or Dissertation |
| Format | application/pdf |
| Coverage | Doctor of Philosophy (Department of Chemical Engineering.) |
| Rights | All items in eScholarship@McGill are protected by copyright with all rights reserved unless otherwise indicated. |
| Relation | alephsysno: 001425462, proquestno: NN00072, Theses scanned by UMI/ProQuest. |
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