Rotary Kilns: Transport Phenomena and Transport Processes

Rotary Kilns—rotating industrial drying ovens—are used for a wide variety of applications including processing raw minerals and feedstocks as well as heat-treating hazardous wastes. They are particularly critical in the manufacture of Portland cement. Their design and operation is critical to their efficient usage, which if done incorrectly can result in improperly treated materials and excessive, high fuel costs. This professional reference book will be the first comprehensive book in many years that treats all engineering aspects of rotary kilns, including a thorough grounding in the thermal and fluid principles involved in their operation, as well as how to properly design an engineering process that uses rotary kilns. Chapter 1: The Rotary Kiln Evolution & Phenomenon Chapter 2: Basic Description of Rotary Kiln Operation Chapter 3: Freeboard Aerodynamic Phenomena Chapter 4: Granular Flows in Rotary Kilns Chapter 5: Mixing & Segregation Chapter 6: Combustion and Flame Chapter 7: Freeboard Heat Transfer Chapter 8: Heat Transfer Processes in the Rotary Kiln Bed Chapter 9: Mass & Energy Balance Chapter 10: Rotary Kiln Minerals Process Applications Readership •Professional Mechanical Engineers working in heating and drying processes; Chemical Engineers; Materials Engineers Contents Chapter 1: The Rotary Kiln Evolution & Phenomenon The Rotary Kiln Evolution Types of Rotary Kilns Wet Kilns Long Kilns Short Dry Kilns Coolers and Dryers References Chapter 2: Basic Description of Rotary Kiln Operation Subtopics anticipated will include but not limited to the following: Bed Phenomenon Geometrical Features and their Transport Effects Transverse Bed Motion Experimental Observations of Transverse Flow Behavior Axial Motion Dimensionless Residence Time References Chapter 3: Freeboard Aerodynamic Phenomena Fluid Flow in Pipes - General Background Basic Equations of Multicomponent Reacting Flows Development of a Turbulent Jet Confined Jets Swirling Jets Precessing Jets The Particle-laden Jet Dust Entrainment Induced Draft Fan References Chapter 4: Granular Flows in Rotary Kilns Flow of Granular Materials (Granular Flows) The Equations of Motion for Granular Flows Particulate Flow Behavior in Rotary Kilns Overview of the Observed Flow Behavior in a Rotary Drums Modeling the Granular Flow in the Transverse Plain Particulate Flow Model in Rotary Kilns Model Description Simplifying Assumptions Governing Equations for Momentum Conservation Integral Equation for Momentum Conservation Solution of the Momentum Equation in the Active Layer of the Bed Velocity Profile in the Active Layer Density and Granular Temperature Profiles An Analytical Expression for the Thickness of the Active Layer Numerical Solution Scheme for the Momentum Equation Model Results and Validation Application of the Flow Model References Chapter 5: Mixing & Segregation Modeling of Particle Mixing and Segregation in Rotary Kilns Bed Segregation Model The Governing Equations for Segregation Boundary Conditions Solution of the Segregation Equation Numerical Solution of the Governing Equations Validation of the Segregation Model Application of Segregation Model References Chapter 6: Combustion and Flame Combustion Mole and Mass Fractions Combustion Chemistry Practical Stoichiometry Adiabatic flame temperature Types of Fuels used in Rotary Kilns Coal Types, Ranking, and Analysis Petroleum Coke Combustion Scrap Tire Combustion Pulverized Fuel (coal/coke) Firing in Kilns Pulverized Fuel Delivery and Firing Systems Estimation of Combustion Air Requirement Reaction Kinetics of Carbon Particles Fuel Oil Firing Combustion Modeling Flow Visualization Modeling (Acid Alkali Modeling) Mathematical Modeling including CFD Gas-Phase Conservation Equations used in CFD Modeling Particle-Phase Conservation Equations used in CFD Modeling Emissions Modeling CFD Evaluation of a Rotary Kiln Pulverized Fuel Burner Reference Chapter 7: Freeboard Heat Transfer Overview of Heat Transfer Mechanisms Conduction Heat Transfer Convection Heat Transfer Conduction-Convection Problems Shell Losses Refractory Lining Materials Radiation Heat Transfer The concept of blackbody Radiation Shape Factors Radiation Exchange Between Multiple Gray Surfaces Radiative Effect of Combustion Gases Heat Transfer Coefficients for Radiation in the Freeboard of a Rotary Kiln Radiative Exchange from the Freeboard Gas to Exposed Bed and Wall Surfaces Radiative Heat Transfer among Exposed Freeboard Surfaces Reference Chapter 8: Heat Transfer Processes in the Rotary Kiln Bed Heat Transfer between the Covered Wall and the Bed Modified Penetration Model for Rotary Kiln Wall-to-Bed Heat Transfer Effective Thermal Conductivity of Packed Beds Effective Thermal Conductivity in Rotating Bed Mode Thermal Modeling of Rotary Kiln Processes Description of the Thermal Model One-dimensional Thermal Model for Bed and Freeboard Two-dimensional Thermal Model for the Bed The Combined Axial and Cross-sectional Model – The Quasi 3-Dimensional Model for the Bed Solution Procedure Model Results and Application Single-Particle Heat transfer Modeling for Expanded Shale Processing Reference Chapter 9: Mass & Energy Balance Chemical Thermodynamics Gibbs Free Energy and Entropy Global Heat and Material Balance Thermal Module for Chemically Reactive System Mass Balance Inputs Chemical Compositions Energy Balance Inputs Chapter 10: Rotary Kiln Minerals Process Applications Lime Making Limestone Dissociation (Calcination) The rotary Lime Kiln The Cement Making Process The Cement Process chemistry Rotary Cement Kiln Energy Usage Mineral Ore Reduction Processes in Rotary Kilns The Rotary Kiln SL/RN Process Roasting of Titaniferous Materials The Rotary Kiln Lightweight Aggregate Making Process Raw Material Characterization Mineralogy Thermal History References Appendices. Author Information By Akwasi A Boateng.