Brosnan D.A., Robinson G.C. Introduction to Drying of Ceramics with Laboratory Exercises

The American Ceramic Society, 2003. — 278 p.N order to accommodate readers with a range of interests and abilities, most chapters are divided into sections by basic and advanced concepts. The sections on basic concepts are intended for those readers who are interested in the practical issues and usually involve only simple mathematics. The sections on advanced concepts involve more theoretical analysis using appropriate mathematical expressions
The terminology used in this book is similar to that in the Chemical Engineer’s Handbook (John Wiley and Sons). This terminology was adopted to make the book consistent with that of the widest usage in engineering practice. English dimensions or units are used consistent with current engineering practice in North America, and metric dimensions are also provided in most sections. Text boxes indicate important facts or key concepts for readersList of figures
List of tablesIntroduction to drying
Basic ConceptsExpressing the Moisture Content of a Powder or a Ceramic Product
Adding Water to a Completely Dry Ceramic and Subsequently
Removing that Moisture
Systems and Segments of Space
Evaporation and Convection Drying Processes
Enthalpy, Energy Balances, and Reference Temperatures
Trends in Drying and Advanced Drying Processes
Drying Products Containing Nonaqueous Liquids
Dryer Stack Emissions and Air Pollution
Costs Involved in Drying Ceramics
Drying Defects
Advanced Concepts
Thermodynamic Considerations
The Carnot Cycle
Thermodynamic Equilibrium
The Clausius-Clapeyron Equation
Problems
Water, air, and water vapor
Water
ntroduction
Density
Surface Tension
Surface Tension and Capillary Suction
Scosity
Apor Pressure
Phase Relationships for Water
Effect of Solutes (Dissolved Solids) on Vapor Pressure
Air
Composition of Air and Air Pollution
Properties of Air
Air-Water Vapor MixturesAbsolute and Relative Humidity
Characterizing Atmospheres Using Wet and Dry Bulb Thermometers
Enthalpy of Air–Water Vapor Mixtures
Dew Point and Frost Point Temperatures
Problems
Drying mechanisms in particulate systems
Basic ConceptsBound Water in Particulate Systems: Hygroscopic Water
Bound Water in Particulate Systems: Capillary Water
Nonbound Water in Particulate Systems: Pore Water and Forming Water
Stages of Drying
The Rate and Stages of Drying
Stage I: the Constant Rate Period
Stage II: the First Declining Rate Period
Stage III: the Second Declining Rate Period
Introduction to Drying Shrinkage
ProblemsPsychrometry
Reading and Interpreting Psychrometric Charts
Basic Concepts
Basic Operations with Psychrometric Charts: Locating Points on the
Psychrometric Chart
Further Operations with Psychrometric Charts: Derived Units
Further Operations with Psychrometric Charts: Mixing Air Segments
Further Operations with Psychrometric Charts: Effect of Altitude
Further Operations with Psychrometric Charts: Plotting Points on the
Psychrometric Chart to Illustrate Changes
Further Operations with Psychrometric Charts: Computer-Aided
Interpretation of Psychrometric Charts
Advanced Concepts: Summary of Equations for Psychrometric
PropertiesPercentage Humidity and Relative Humidity
Plotting Lines of Constant Relative Humidity on the Psychrometric
Chart
Enthalpy of Water Vapor–Gas Mixtures
Constructing Psychrometric Charts
Problems
Characterization of dryer operations
Analyzing Dryer Performance Using Psychrometric Charts
Introduction to Dryer Analysis
Representing Dryer Operation Using Bar Charts
Representing Dryer Operation on Psychrometric Charts
Sankey Diagrams and Dryer Thermal Efficiency
Representing Operating Dryers: Sankey Diagrams
Dryer Thermal Efficiency
Problems
Dryer control: controlling countercurrent convection dryersThe Single, Closed Tunnel Concept
Pore Water Zone: The Final Stage of Drying toward the Exit End of the Dryer
Controlling the Shrinkage Water Stage (Product Entrance End Zone of the Dryer)
Basic Shrinkage Zone Control
Fan Transfer between Shrinkage and Pore Water Zones
Time Lag
Recirculation Systems
Preheat Stage
The Composite Dryer
Problems
Drying defects and drying shrinkageDrying Cracks Resulting from Material Preparation
Shrinkage Gradient Cracks
Nonhomogeneity in Structure
Water Gradient from Nonuniform Material
Water Gradient from Drying Gradient
Forming Flaws and Drying Cracks
Thickness Gradients
Theoretical Treatment of Drying ShrinkageProblems
Additional Reading
Advanced drying technologiesMicrowave Drying
Physics of Microwave Drying
Advantages of Microwave Drying
Microwave Drying Systems
A practical Example of Microwave Drying
Radio Frequency Drying
Brief Description of Radio Frequency Drying
A practical Example of Radio Frequency Drying
Costs of Microwave and Radio Frequency Drying
Airless DryingSemicontinuous Systems
Advantages of Airless Drying
Fast Drying Using ConvectionFast Drying Plants
Problems
Additional Reading
Laboratory exercisesSuggested Laboratory Safety Rules
Conducting Laboratory Exercises
Experiment 1: Particle Size (Screen Analysis)
Purpose
Procedure
Screen Analysis of Dried (Naturally Agglomerated) Materials
Preparation of a Specimen for Screen Analysis after Washing (Not
Agglomerated) and for a Sedimentation Test (Experiment 2)
Questions
Experiment 2: Particle Size (Sedimentation Analysis to Determine Colloidal Sizes)
Purpose
Procedure
Start the Sedimentation Analysis
Complete the Table
Using Stokes Law to Calculate the Size of a Particle Falling at Any Time
Using Sedimentation Analysis Data
Producing a Total Particle Size Distribution
Example Problem for Total Size Distribution
Experiment 3: Moisture Adsorption and Ignition Loss
Purpose
Procedure
Loi experiment
Ma experiment
Calculations
Experiment 4: Extrusion of Clay Bodies
Purpose
Procedure
Data
Questions
Experiment 5: Stages of Drying
Purpose
Procedure
Data
Calculations
Graphing Results
Experiment 6: Permeability in Drying (Moisture Movement in Drying)
Purpose
Procedure
Second Day, Afternoon
Calculations
Questions
Experiment 7: Mix Pelletizing
Purpose/Introduction
Procedure
Experiment 8: Thermal Gradient Furnace Testing /Thermal Expansion
Purpose/Introduction
Procedure
Questions
Experiment 9: Firing Traditional Ceramics
Purpose/Introduction
Formulas
Data Table and Calculations
Questions
Experiment 10: Firing Dry-Pressed Ceramics
Purpose/Introduction
Procedure
Calculated Values
Questions
Experiment 11: Advanced Properties of Pressed and Extruded Ceramics
ntroduction
Suggested Data to be Acquired
Questions
Appendix 1: symbols, terms, and units of measurement
Appendix 2: conversion factors
Appendix 3: answers to selected problems
Appendix 4: additional psychrometric charts