Decanter Centrifuge Handbook

Edited By

  • A. Records
  • K Sutherland

Scope of Publication
A reference work for process designers and users of decanters, this book aims to bridge the information gap in this field - that between academic theory promoted in student textbooks and case study data in manufacturers sales literature.

It includes information on design and specification, preparing the reader to select and correctly size equipment.

As a design or project engineer working with vendors to make final equipment selection, this work provides the readers with the full facts before they start talking to product vendors.

In an environment of industry consolidation, the handbook allows you to track suppliers old and new, providing a basis on which users can find the new relevant company for the parts/service he/she wishes to purchase.

Once an equipment purchase is made, the user needs to be made aware of how to optimally operate decanters. The Decanter Centrifuge Handbook covers relevant (process) operating issues such as instrumentation and control and the use of flocculents.

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Process designers, manufacturers and users of decanters.


Book information

  • Published: March 2001
  • Imprint: ELSEVIER
  • ISBN: 978-1-85617-369-8

Table of Contents

Decanter development Manufacturers: who entered the markeplace, who left, who owns whom, specialities of major suppliers
Trends in technology

Decanter Design
Basic construction: vertical/horizontal, concurrent/countercurrent, leading/trailing conveyor, design limitation, natural frequency versus L/D and design
Materials of construction: maximum bowl speed versus bowl diameter, materials of construction
Basic components: bowl, conveyor, casing, drive, backdrive, gearbox, frame and mounting, inlets and outlets, bearings and seals
Variants: bowl diameter, clarifying length, beach angle, scolling aids: liners and grooving, conveyor leads, conveyor pitch, flight profile, cant and rake, flow: axial helical and vane assisted, baffle designs, feed zone design and position, polymer inlets, gearbox designs and alternatives, cake discharge, brakes, weat inserts, tiles, noise abatement features, surface finishes
Special features: three phase design, screen bowls, double beach design, nozzle cake discharge, vanes and discs, casing baffles, windage control, cake collectors, cake reslurry, back drive systems, centripetal pump, skimmer pipe, drain valves, high temperature and high pressure designs, compound beach angles
Instrumentation: Tachometers, proximity probes, torque monitoring, power meters, controllers

The Market
Where decanters are used, how many are used, importance in that market, impact on decanter design and use for manufacturer and end-user

Applications: effluent - municipal and industrial, drilling muds, olive and palm oils, proteins, starches, brewery and distillery grains, dairy, petrochemicals, minerals, pharmaceuticals, heavy chemicals, clays, water works sludges, fish meal, surimi, rendering
Application Types: clarification, classification, dewatering, extra dry solids, washing, reslurry wash, thickening

Clarification: sigma theory, classification, thickening, compaction, limitations, examples
Conveying: beta theory, scrolling, scrolling efficiency, dewatering examples
Power Consumption: W&F, scrolling, process, braking, total
Polymer Addition: mixing, flocculation time, addition point, consumption
Pressure developed: in liquor, in cake, equivalent of torque, g-force
Scaling: conveying, power, torque, dryness, capacity
Particle size distribution: cut point, surface area, converting number of weight distribution, use with sigma and capacity
Moving layer theory
Calculating the effect of vanes and discs
Fundamental studies

Types of flocculents: polycrylomides and others, anoimic, cationic, nonionic, molecular weight, ionic charge
Dosing Make-up: methods, equipment, time, concentration, addition point

Test work and data
Test methods: equipment needed, planning the test, data needed, manipulating the data, examples of data to illustrate theory

Calculations and scale-up
Identifying the pertinent method
Data needed
Preparing the date: function to be calculated
Mass balance
Polymer Dose
Power Calculations
Worked examples

Plant Instrumentation and Control
The complete decanter plant is considered. Feed and polymer pumps, polymer make up systems, off-take conveyors and centrate receivers will all be included. Instrumentation in common use will be enumerated including mechanical and electronic devices. These will include level indicators, speed meters, torque meters, solids in liquid monitors and meters, timers, starters, vibration monitors and bearing condidtion monitors

Decanter Features for special applications

Tables of decanter data

Nomenclature, acknowledgements, references, index