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