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SLS 6: Centrifugation

SLS 6: Centrifugation
     SLS 6A: Centrifugation - Filtering Centrifuges
         1. Introduction
             1.1 Background and Objectives
             1.2 Scope of the report
         2. Types and Applications
             2.1 Introduction
                 2.1.1 Background and Objectives
                 2.1.2 Scope of Report
             2.2 Maintypes of filtering centrifuge
                 2.2.1 Centrifuges with Continuous Slurry Feed
                 2.2.2 Centrifuges with Batch Slurry Feed
             2.3 Applications for filtering centrifuges
                 2.3.1 Slip Discharge Cone Screen
                 2.3.2 Baffle Ring Centrifuge (Krauss-Maffei)
                 2.3.3 Vibration Discharge Cone Screen
                 2.3.4 Tumbler Centrifuge
                 2.3.5 Conveyor Discharge Cone Screen
                 2.3.6 Directed Flow Centrifuge (Heinkel)
                 2.3.7 Screen Bowl Centrifuge
                 2.3.8 Pusher Centrifuges
                 2.3.9 Manual Discharge Basket Centrifuges
                 2.3.10 Plough Discharge Batch Basket Centrifuges
                 2.3.11 Peeler Centrifuges
                 2.3.12 Inverting Filter Centrifuge (Heinkel)
             2.4 Flowsheets for filtering centrifuges
                 2.4.1 Crystal Washing
                 2.4.2 Slurry Dewatering
                 2.4.3 Clarification of Filtrate
                 2.4.4 Dewatering Coarse Solids
             2.5 References
         3. Theory and Design
             3.1 introduction
             3.2 Stages in centrifugal filtration
             3.3 Basic filtering centrifuge theory
             3.4 Theoretical treatments for the various stages
                 3.4.1 The cake build-up stage
                 3.4.2 The permeation stage
                 3.4.3 The drainage stage
                 3.4.4 Washing stages
         4. Selection and Sizing
             4.1 Introduction
             4.2 Why select a filter centrifuge?
                 4.2.1 When to use a filter centrifuge
                 4.2.2 When not to use a filtration centrifuge
             4.3 Criteria for selecting a filter centrifuge
                 4.3.1 Feed slurry properties
                 4.3.2 Process requirements
                 4.3.3 Machine characteristics
         5. Test Procedures and Data Analysis
             5.1 Introduction
             5.2 Laboratory scale testing
                 5.2.1 Vacuum filtration tests
                 5.2.2 Filter bucket centrifuge tests
                 5.2.3 Evaluation of data from bucket centrifuge tests
                 5.2.4 Use of a filter bucket with transparent sides
                 5.2.5 Washing tests in the filter bucket centrifuge
                 5.2.6 Bench scale centrifuge tests
                 5.2.7 Determining the sliding and conveying properties of filter cakes
             5.3 Pilot scale testing and optimisation
                 5.3.1 Introduction
                 5.3.2 Setting up the pilot scale test
                 5.3.3 Pilot scale testing of continuous centrifuges.
             5.4 Pilot scale testing of batch basket centrifuges
                 5.4.1 Introduction
                 5.4.2 Variables to be tested
                 5.4.3 Some important factors in testing batch basket centrifuges
             5.5 Scale up from pilot scale centrifuge tests
         6. Installation and Operation
             6.1 Introduction
             6.2 Flowsheets for filtering centrifuges
                 6.2.1 Crystal washing
                 6.2.2 Slurry dewatering
                 6.2.3 Clarification of filtrate
                 6.2.4 Dewatering coarse solids
             6.3 Control of filtering centrifuges
                 6.3.1 Introduction
                 6.3.2 Control of continuously operating filter centrifuges
                 6.3.3 Control of batch filter centrifuges
             6.4 Installation of centrifuges
                 6.4.1 Weight and dimensions
                 6.4.2 Space and services for maintenance
                 6.4.3 Mounting and vibration
                 6.4.4 Location of the machine in relation to feed and product streams
                 6.4.5 Type and location of drive
             6.5 Operational problems
                 6.5.1 Introduction
                 6.5.2 Balance and vibration
                 6.5.3 The distribution of slurry feed to multiple batch filtration centrifuges
                 6.5.4 Wear
                 6.5.5 Blinding and holing of screens or cloth media
                 6.5.6 Glazed heel cakes
                 6.5.7 Application of wash liquids
                 6.5.8 Difficulties in discharging cakes
             6.6 Maintenance
                 6.6.1 Introduction
                 6.6.2 Cost of maintenance
                 6.6.3 Lubrication
             6.7 Safety aspects
                 6.7.1 Introduction
                 6.7.2 Mechanical hazards
                 6.7.3 Fire and explosion hazards
                 6.7.4 Toxic hazards
                 6.7.5 Noise
         7. Nomenclature
         8. References
     SLS 6B: Centrifugation - Sedimenting Centrifuges
         1. Introduction
             1.1 Scope of the Report
         2: Types and Applications
             1 INTRODUCTION
                 1.1 Definition and Purpose
                 1.2 Scope of the Manual
             2 LABORATORY CENTRIFUGES
                 2.1 Introduction
                 2.2 Analytical and Chemical Bottle Centrifuges
                 2.3 Ultra Centrifuges
                 2.4 Zonal Centrifuge
                 2.5 Moving Boundary
                 2.6 Buoyant Separation
                 2.7 Counter Current Centrifugation (Elutriation)
                 2.8 Applications and Limitations
                 2.9 Maintenance
             3 THE TUBULAR BOWL CENTRIFUGE
                 3.1 Description
                 3.2 Operating Conditions
                 3.3 Applications and Limitations
                 3.4 Maintenance
             4 THE SOLID BOWL CENTRIFUGE
                 4.1 Description
                 4.2 Mixer Centrifuge
                 4.3 Operating Conditions
                 4.4 Applications and Limitations
                 4.5 Maintenance
             5 DISC STACK CENTRIFUGES
                 5.1 Description
                 5.2 Operating Conditions
                 5.3 Applications and Limitations
                 5.4 Maintenance
             6 SCROLL DISCHARGE CENTRIFUGES
                 6.1 Description
                 6.2 Definitions
                 6.3 Process Effect of Machine Variables
                 6.4 Machine Variables
                 6.5 Effects of Machine Variables on Process
                 6.6 Design Variations
                 6.7 Combined Centrifugation and Drying
                 6.8 Feed Acceleration
                 6.9 Operating Conditions
                 6.10 Applications and Limitations
                 6.11 Maintenance
             7 CONTROL OF CENTRIFUGES
                 7.1 Introduction
                 7.2 Batch Centrifuges
                 7.3 Semi-Continuous Centrifuge
                 7.4 Continuous Centrifuges
                 7.5 Malfunction - Alarm Systems
             8 SAFETY ASPECTS OF CENTRIFUGES
                 8.1 Introduction
                 8.2 Mechanical Hazards
                 8.3 Centrifuge Operational Safety
                 8.4 Hazards of Fire and Explosion
                 8.5 Toxicity Hazards
                 8.6 Evaluation and Control of Hazards
                 8.7 Inert Gas Blanketing
                 8.8 Bio-Safety - A Special Case
                 8.9 Noise Control
                 8.10 Pressure & fume tight decanter centrifuges
             9 SEDIMENTING CENTRIFUGE TECHNOLOGY
             10 REFERENCES
         3. Theory and Design
             3.1 General Theory
             3.2 Application of Theory to Different Centrifuge Types
             3.3 Efficiency Factors
         4. Selection and Sizing
             4.1 Introduction
             4.2 Slurry Evaluation
                 4.2.1 Minimum particle size
                 4.2.2 Feed solids content and flow rate
                 4.2.3 Process circuit requirements
         5. Test Procedures and Data Analysis
             5.1 Tests for Selection and Sizing
                 5.1.1 Introduction
                 5.1.2 Settling tests
                 5.1.3 Laboratory centrifuge tests
             5.2 Pilot Scale and Full Scale Tests
         6. Installation and Operation
             6.1 Control of Centrifuges
                 6.1.1 Introduction
                 6.1.2 Batch Centrifuges
                 6.1.3 Semi-Continuous Centrifuge
                 6.1.4 Continuous Centrifuges
                 6.1.5 Malfunction - Alarm Systems
             6.2 Safety Aspects of Centrifuges
                 6.2.1 Introduction
                 6.2.2 Mechanical Hazards
                 6.2.3 Hazards of Fire and Explosion
                 6.2.4 Toxicity Hazards
                 6.2.5 Evaluation and Control of Hazards
                 6.2.6 Inert Gas Blanketing
                 6.2.7 Bio-Safety - A Special Case
                 6.2.8 Noise Control
         7. Nomenclature
         8. References

Volume SLS VIA : Centrifugation - Filtering Centrifuge.

 

Part 1   Introduction
Part 2   Types and Applications
Part 3   Theory and Design
Part 4   Selection, Sizing and Operation (Filtering Centrifuges - SAR
Part 5   Test Procedures and Data Analysis
Part 6   Equipment for specific application

 

This manual volume reviews the theoretical and practical aspects of centrifugal filtration and contains information on the types of equipment available, selection and test methods, scale-up and optimisation, operational control and safety. Part 2 describes the mechanical and operational features of the main types of filtering centrifuge. Filter cake washing is considered as well as centrifuges for continuous and batch slurry feeds and solids discharge. Part 3 outlines the theory behind centrifugal filtration and deals separately with the various operations involved in atypical filtration cycle, which include; cake formation, permeation, washing and de-watering. Models based on fundamental equations that govern centrifugal filtration are presented for steady-state and batchwise operations. Part 4 starts by discussing the reasons for selecting a filtering centrifuge before other solid/liquid separation equipment and then goes on to review the selection of a particular type of centrifuge in relation to: feed slurry properties, process requirements and machine characteristics. Laboratory and pilot scale test work is described in Part 5 for the different types of machine and recommendations are made as to how the test data can be used to scale-up and optimise the design of a filtering centrifuge system. The installation, control, operation and maintenance of continuous and batch filtering centrifuges are also described in this part, covering aspects such as weight, space requirement, mounting and vibration, location and control systems. Part 5 also provides a brief survey of the safety aspects associated with filtering centrifuges and indicates where supplementary information can be found. The areas of safety that are covered include mechanical, fire and explosive hazards, toxic hazards and noise. Part 6 matches different types of equipment to specific applications.

 


 

Volume SLS VIB : Centrifugation - Sedimenting Centrifuge.

 

Part 1 Introduction
Part 2 Types and Applications
Part 3 Theory and Design
Part 4 Selection, Sizing and Operation (Sedimenting Centrifuges)
Part 5 Test Procedures and Data Analysis
Part 6 Equipment for specific application

 

This manual presents an overview of sedimenting centrifuges and is intended as a general survey of the different types of machine and the sorts of applications for which they are suited. Part 2 is concerned with the individual centrifuge types; providing a description of the machines and their modifications, as well as summaries of their operating conditions, reviews of their applications and limitations, and notes on maintenance. In Part 3 the general theory of centrifugal settling is presented. The ‘S Theory’ of centrifugal sedimentation is given with expressions for the ‘S Factor’ for solid bowl centrifuges of differing geometry. Efficiency factors are introduced which take into account the deviations from the ‘ideal’ general theory which centrifuges show in practice. Part 4 is intended to aid the selection of sedimenting centrifuges from the different types available and to help in determining the optimum size and operating conditions of the machine. Relevant tests to evaluate the process stream properties are described as well as tests for machine selection and sizing. The control of centrifuges is considered under batch, semi-continuous and continuous operating regimes. Test procedures, data analysis and aspects of safety are covered in Part 5. Safety issues are mainly concerned with safe operation of sedimenting centrifuges and the evaluation and control of certain hazards. The particular areas considered are; mechanical hazards, fire and explosion hazards, toxicity, biosafety and noise control. Part 6 deals with specific types of centrifuges and their applications.