CONTENTS

ABOUT THE BOOK
The history of Unit Operations in Food Processing, and how it came to be published on the web.

CHAPTER 1.
INTRODUCTION
Method of studying food process engineering
Basic principles of food process engineering
Conservation of mass and energy
Overall view of an engineering process.
Dimensions and units
Dimensionssymbols
Units
Dimensional consistency
Unit consistency and unit conversion
Dimensionless ratiosspecific gravity
Precision of measurement
Summary.
Problems.

CHAPTER 2.
MATERIAL AND ENERGY BALANCES
Basic principles
Material balances
Basis and units
total mass and composition
concentrations
Types of Process situations
continuous processes
blending
Layout
Energy balances
Heat balancesenthalpylatent heatsensible heatfreezing
       dryingcanning
Other forms of energymechanical energyelectrical energy
Summary
Problems

CHAPTER 3.
FLUID-FLOW THEORY.
Introduction
Fluid staticsfluid pressureabsolute pressures gauge pressures
       head
Fluid dynamics
Mass balancecontinuity equation
Energy balance
Potential energy
Kinetic energy
Pressure energy
Friction loss
Mechanical energy
Other effects
Bernouilli's equationflow from a nozzle
Viscosityshear forcesviscous forces
Newtonian and Non-Newtonian Fluidspower law equation
Streamline and turbulent flowdimensionless ratios
       Reynolds number
Energy losses in flow
Friction in PipesFanning equationHagen Poiseuille equation
       Blasius equationpipe roughnessMoody graph
Energy Losses in Bends and Fittings
Pressure Drop through Equipment
Equivalent Lengths of Pipe
Compressibility Effects for Gases
Calculation of Pressure Drops in Flow Systems
Summary
Problems

CHAPTER 4.
FLUID-FLOW APPLICATIONS
Introduction
Measurement of pressure in a fluidmanometer tube Bourdon tube
Measurement of velocity in a fluidPitot tubePitot-static tube
       Venturi meterorifice meter
Pumps and fans
Positive Displacement Pumps
Jet pumps
Air-lift Pumps
Propeller Pumps and Fan
Centrifugal Pumps and Fanspump characteristicsfan laws
Summary
Problems

CHAPTER 5.
HEAT-TRANSFER THEORY
Introduction
Heat Conductionthermal conductancethermal conductivity
Thermal Conductivity
Conduction through a SlabFourier equation
Heat Conductances
Heat Conductances in Series
Heat Conductances in Parallel
Surface-Heat TransferNewton's Law of Cooling
Unsteady-State Heat TransferBiot NumberFourier Number
       charts
Radiation-Heat TransferStefan-Boltzmann Lawblack body
       emissivity grey bodyabsorbtivityreflectivity
Radiation between Two Bodies
Radiation to a Small Body from its Surroundings
Convection-Heat Transfer
Natural ConvectionNusselt NumberPrandtl Number
       Grashof Number
Natural Convection Equationsvertical cylinders and planes
       horizontal cylindershorizontal planes
Forced Convection
Forced-convection Equationsinside tubesover plane surfaces
       outside tubes
Overall Heat-Transfer Coefficientscontrolling terms
Heat Transfer from Condensing Vapours
       vertical tubes or plane surfaceshorizontal tubes
Heat Transfer to Boiling Liquids
Summary
Problems

CHAPTER 6.
HEAT-TRANSFER APPLICATIONS
Introduction
Heat Exchangers
Continuous-flow Heat Exchangersparallel flowcounter flow
       cross flow heat exchanger heat transferlog mean temperature difference
Jacketed Pans
Heating Coils Immersed in Liquids
Scraped Surface Heat Exchangers
Plate Heat Exchangers
Thermal Processing
Thermal Death Time
F valuesEquivalent Killing Power at Other Temperatures
       z valuesterilization integrationtime/temperature curves
Pasteurizationmilk pasteurization
       High Temperature Short Time HTST
Refrigeration, Chilling and Freezing
Refrigeration Cycletemperature/enthalphy chartevaporator
       condenseradiabatic compressioncoefficient of performance
       ton of refrigeration
Performance Characteristics
Refrigerantsammoniarefrigerant 134A
Mechanical Equipment
Refrigeration EvaporatorHeat transfer coefficientfins
Chilling
FreezingPlank's equationfreezing timeshape factors
Cold Storage
Summary
Problems

CHAPTER 7.
DRYING
Basic Drying Theory
Three States of Waterphase diagram for water
       vapour pressure/temperature curve for water
Heat Requirements for Vaporization
Heat Transfer in Drying
Dryer Efficiencies
Mass Transfer in Dryingmass transfer coefficient
Psychrometryabsolute humidityrelative humidity
       dew pointhumid heat
Wet-bulb Temperaturesdry bulb temperatureLewis number
Psychrometric Charts
Measurement of Humidityhygrometers
Equilibrium Moisture Content
Air Dryingdrying rate curves
Calculation of Constant Drying Rates
Falling-rate Drying
Calculation of Drying Times
Conduction Drying
Drying Equipment
Tray Dryers
Tunnel Dryers
Roller or Drum Dryers
Fluidized Bed Dryers
Spray Dryers
Pneumatic Dryers
Rotary Dryers
Trough Dryers
Bin Dryers
Belt Dryers
Vacuum Dryers
Freeze Dryers
Moisture Loss in Freezers and Chillers
Summary
Problems

CHAPTER 8.
EVAPORATION
The Single-Effect Evaporator
Vacuum Evaporation
Heat Transfer in Evaporators
Condensers
Multiple-Effect Evaporation
Feeding of Multiple-effect Evaporators
Advantages of Multiple-effect Evaporators
Vapour Recompression
Boiling Point ElevationRaoult's LawDuhring's rule
       Duhring plotlatent heats of vaporization
Evaporation of Heat-Sensitive Materials
Evaporation Equipment
Open Pans
Horizontal-tube Evaporators
Vertical-tube Evaporators
Plate Evaporators
Long-tube Evaporators
Forced-circulation Evaporators
Evaporation for Heat-sensitive Liquids
Summary
Problems

CHAPTER 9.
CONTACT-EQUILIBRIUM PROCESSES
Introductioncontact equilibrium separationphase distribution
       equilibrium distribution coefficients

PART 1: THEORY
Concentrationsmole fractionpartial pressureAvogadro's Law
Gas-Liquid Equilibriapartial vapour pressureHenry's Law
       solubility of gases in liquids
Solid-Liquid Equiibriasolubility in liquids
       solubility/temperature relationshipsaturated solution
       supersaturated solution
Equilibrium-Concentration Relationshipsoverflow/underflow
       equilibrium diagram
Operating Conditionscontact stagesmass balances
Calculation of Separation in Contact-Equilibrium Processes
       combining equilibrium and operating conditions
       deodorizing/steam strippingMcCabe/Thiele diagram

PART 2: APPLICATIONS
Gas Absorptionnumber of contact stages
Rate of Gas AbsorptionLewis and Whitman Theory
Stage-equilibrium Gas Absorption
Gas-absorption Equipment
Extraction and Washingequilibrium and operating conditions
       McCabe Thiele diagram
Rate of Extraction
Stage-equilibrium Extraction
Washing
Extraction and Washing Equipmentextraction battery
Crystallizationmother liquor
Crystallization Equilibriumgrowthnucleation
       metastable region
       seed crystalsheat of crystallization
Rate of Crystal Growth
Stage-equilibrium Crystallization
Crystallization Equipmentscraped surface heat exchanger
       evaporative crystallizer
Membrane Separationsosmotic pressureultrafiltration
       reverse osmosis
Rate of Flow Through MembranesVan't Hoff equation
       Diffusion equationsSherwood numberSchmidt number
Membrane Equipment
DistillationEquilibrium relationships
       boiling temperature/concentration diagram azeotropes
Steam Distillation
Vacuum Distillation
Batch Distillation
Distillation Equipment
Summary
Problems

CHAPTER 10.
MECHANICAL SEPARATIONS
Introduction
The velocity of particles moving in a fluidterminal velocity
       drag coefficient terminal velocity magnitude.
SedimentationStokes' Law
Gravitational Sedimentation of Particles in a Liquidzones
       velocity of rising fluidsedimentation equipment
Flotation
Sedimentation of Particles in a Gas
Settling Under Combined Forces
Cyclones- optimum shapeefficiency
Impingement separators
Classifiers
Centrifugal separationscentrifugal forceparticle velocity
Liquid Separationradial variation of pressure
       radius of neutral zone
Centrifuge Equipment
Filtrationrates of filtrationfilter cake resistance
       equation for flow through the filter
Constant-rate Filtration
Constant-pressure Filtrationfiltration graph
Filter-cake Compressibility
Filtration Equipment
Plate and frame filter press
Rotary filters
Centrifugal filters
Air filters
Sievingrates of throughputstandard sieve sizes
       cumulative analysesparticle size analysis
       industrial sievesair classification
Summary.
Problems.

CHAPTER 11.
SIZE REDUCTION
Introduction
Grinding and cutting.
Energy Used in GrindingKick's LawRittinger's Law
       Bond's LawWork Index
New Surface Formed by Grindingshape factors
Grinding equipment.
Crushers
Hammer mills
Fixed-head mills
Plate mills
Roller mills
Miscellaneous milling equipment
Cutters
Emulsificationdisperse/continuous phasesstability
       emulsifying agents
Preparation of Emulsionsshearinghomogenization
Summary.
Problems.

CHAPTER 12.
MIXING
Introduction
Characteristics of mixtures.
Measurement of mixingsample sizesample compositions
Particle mixingrandom mixturethorough mixture
       mixing index
Mixing of Widely Different Quantitiesmixing in stages
Rates of Mixingmixing times
Energy Input in Mixing
Liquid mixingpropeller mixersPower numberFroude number
Mixing equipment
Liquid Mixers
Powder and Particle Mixers
Dough and Paste Mixers
Summary.
Problems.

APPENDICES
1. Symbols, units and dimensions
2. Units and conversion factors
3. Some properties of gases
4. Some properties of liquids
5. Some properties of solids
6. Some properties of air and water
7. Thermal data for some food products
8. Steam table - saturated steam
9. (a) Psychrometric charts - normal temperatures
9. (b) Psychrometric charts - high temperatures
10. Standard sieves
11. (a) Pressure/enthalpy chart for refrigerant - R134a
11. (b) Pressure/enthalpy chart for refrigerant - Ammonia

INDEX TO FIGURES

INDEX TO EXAMPLES

REFERENCES

BIBLIOGRAPHY

USEFUL LINKS