New decanter centrifuge technology for improved separation and high throughput

Woon Fong Leung

Research output: Journal article publicationReview articleAcademic researchpeer-review

2 Citations (Scopus)

Abstract

An innovative new technology has been developed to improve clarification and separation of decanter typed centrifuge, which includes solid-bowl and screen-bowl centrifuges. For separation and clarification the new technology has demonstrated to increase substantially the solids recovery, or reduce solids in effluent, at given operating centrifugal gravity level, pool depth, differential speed, and feed rate. The new technology is especially advantageous for "difficult-to-separate" applications such as for feed slurry with (a) fine particles less than 10 microns, (b) small density difference between suspending solids and liquid phase as found in organic and biological solids suspended in aqueous phase, or (c) suspension with high viscosity. For the same solids recovery (or centrate solids), the centrifuge clarifier technology can increase throughput for the decanter typed machine provided the latter is not mechanically limited by the motor and conveyor-drive. When coagulant and/or flocculant are used less dosage is consumed as the technology provides superior separation compared with conventional decanter. Typically there is no effect on cake dryness unless much finer particles get settled in the cake and bring excess moisture which is not removed in the centrifuge. The technology is also attractive for screen-bowl centrifuge when employed in separating high-rate mineral slurries in which higher concentration of unsettled solids in the effluent is the limiting factor due to low speed/centrifugal gravity G and a short cylindrical clarifier providing minimal residence time for the feed. The new technology can be applied to wet classification of slurry with micron-sized feed resulting in much finer (1-2 μm) particles in the product effluent at the same size recovery or yield. The latter finds applications in classification of kaolin, calcium carbonate, silica, mica, talc, and other fine-particle slurries. The centrifuge clarifier technology can be used alone, or in partnership with an improved feed acceleration system wherein feed is instantly accelerated to speed when it is introduced to the separation pool of the centrifuge. Both technologies, when combined, can further improve separation and increase throughput to the centrifuge. Numerous examples are used to illustrate both separation and classification of fine-particle slurry. The centrifuge clarifier and feed acceleration technologies can be used to retrofit almost all existing installed decanter typed centrifuges, or implemented in new centrifuges, to improve throughput and separation.
Original languageEnglish
Pages (from-to)37-51
Number of pages15
JournalFluid - Particle Separations Journal
Volume16
Issue number1
Publication statusPublished - 1 Jun 2004
Externally publishedYes

Keywords

  • Centrifuge
  • Clarifier technology
  • Classification
  • Decanter
  • Feed acceleration
  • Screen bowl
  • Separation
  • Solid bowl
  • Solids recovery
  • Throughput

ASJC Scopus subject areas

  • Fluid Flow and Transfer Processes
  • Filtration and Separation

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