Flash Ironmaking

This book addresses the two major issues faced by the modern steel industry: CO2 emissions and energy consumption. The steel industry accounts for 6.7% of the anthropogenic CO2 emissions and consumes 6% of the total energy consumed in manufacturing. In response to these critical issues, a new technology called flash ironmaking has been developed, aimed at producing iron directly from iron ore concentrate using gaseous reductants/fuels such as natural gas or hydrogen. This ironmaking technology takes advantage of the rapid reaction rate of fine particles and bypasses the palletization process. This book discusses the principles of flash ironmaking, laboratory experiments, and design and operation of a prototype flash reactor. • Provides theories and principles of ironmaking and a novel ironmaking technology. • Includes laboratory experiments to establish the kinetic feasibility of flash ironmaking. • Covers the design and operation of a prototype flash reactor as well as the design of industrial-size flash ironmaking reactors. • Describes various cases of flow sheet development, which forms the basis for process analysis and simulation • Presents economic analysis case studies. Presenting a novel technology that addresses contemporary issues facing one of the largest manufacturing industries, this book is aimed at professionals and researchers in metallurgy, materials engineering, manufacturing engineering, and related disciplines. Cover Half Title Title Page Copyright Page Dedication Table of Contents Abbreviations Nomenclature Preface Acknowledgments Author Chapter 1 Introduction Chapter 2 Current Technologies for Ironmaking 2.1 Blast Furnace Process 2.2 Direct Reduction Processes 2.3 Smelting Reduction Processes 2.3.1 Advantages 2.3.2 Disadvantages Chapter 3 Issues Facing the Steel Industry 3.1 Raw Materials 3.2 Greenhouse Gas Emissions 3.3 Energy Consumption Chapter 4 Flash Ironmaking Technology – Concept Development Chapter 5 Basic Properties and Sources of Magnetite Concentrate Chapter 6 Principles Related to Iron Oxide Reduction 6.1 Thermochemistry 6.1.1 The First Law of Thermodynamics – Heat and Heat Capacity 6.1.2 Physical Changes and Heat Content 6.1.3 Chemical Changes and Standard State 6.1.4 Standard Heat of Formation or Standard Enthalpy of Formation 6.1.5 Standard Heat of Combustion 6.1.6 Hess' Law 6.1.7 Heat of Chemical Reaction 6.1.8 Heat of Reaction at Different Temperatures 6.1.9 Adiabatic Reaction Temperature 6.1.10 Heat of Mixing 6.1.11 The Second Law of Thermodynamics 6.1.12 Activity and Activity Coefficient 6.1.13 Chemical Equilibrium 6.1.14 Calculation of Equilibrium Composition 6.1.15 Ellingham Diagram – ΔG° – T Diagram 6.1.16 Gibbs' Phase Rule 6.1.17 Stability Diagram 6.2 Reaction Kinetics of Fine Solid Particles with a Gas 6.2.1 Introduction 6.2.2 Chemically Controlled Shrinking-Core Kinetics 6.2.3 Nucleation and Growth Kinetics – Avrami–Erofeev Equation 6.2.4 Nucleation and Growth Kinetics – Prout–Tompkins Model (Also Called the Autocatalytic Model) 6.2.5 Solid-State Diffusion Model 6.2.6 Summary of Various Solid-State Reaction Kinetics Models 6.2.7 Analysis of Rate Data 6.2.7.1 The Isothermal Method 6.2.7.2 The Direct Differential Method – Linear T-t Program 6.2.7.3 Coats–Redfern Integral Method – Linear T-t Program 6.2.7.4 Iso-Conversional Methods 6.2.7.5 Sohn's Non-Linear Temperature–Time Program Chapter 7 Development of Flash Ironmaking Technology – Reduction Kinetics of Magnetite Concentrate Particles 7.1 Materials 7.2 Experimental Apparatus 7.3 Experimental Procedure 7.4 Formulation of Reduction Kinetics Equation 7.4.1 Definitions of Parameters 7.4.1.1 Reduction Degree 7.4.1.2 The Amount of Excess Reducing Gas 7.4.1.3 Excess Driving Force 7.4.1.4 Particle Residence Time 7.4.2 Selection of Rate Equation 7.4.3 Determination of the Reaction Order with Respect to Gas Partial Pressures 7.4.4 Effect of Particle Size 7.4.5 Determination of the Activation Energy 7.4.6 Verification of the Absence of the Effects of Mass Transfer and Pore Diffusion 7.5 Results of Rate Measurements and Rate Equations 7.5.1 Reduction by Hydrogen: Temperature Range of 1,150°C–1,350°C 7.5.2 Reduction by Hydrogen: Temperature Range of 1,350°C–1,600°C 7.5.3 Reduction by Carbon Monoxide: Temperature Range of 1,150°C–1,350°C 7.5.4 Reduction by Carbon Monoxide: Temperature Range of 1,350°C–1,600°C 7.5.5 Reduction by H[sub(2)] + CO Mixtures: Temperature Range of 1,150°C–1,350°C 7.5.6 Reduction by H[sub(2)] + CO Mixtures: Temperature Range of 1,350°C–1,600°C 7.5.7 Summary on the Reduction Kinetics of Magnetite Concentrate Particles 7.6 Refinements of the Rate Equations for the Reduction of Concentrate Particles Through Computational Fluid Dynamics Modeling 7.6.1 Approach and Methodology 7.6.2 Numerical Procedure 7.6.3 Modeling Results 7.6.4 Kinetics Analysis Procedure 7.6.5 Complete Rate Equations 7.6.5.1 Reduction by Hydrogen: Temperature Range of 1,150°C–1,350°C 7.6.5.2 Reduction by Hydrogen: Temperature Range of 1,350°C–1,600°C 7.6.5.3 Reduction by Carbon Monoxide: Temperature Range of 1,150°C–1,350°C 7.6.5.4 Reduction by Carbon Monoxide: Temperature Range of 1,350°C–1,600°C 7.6.5.5 Reduction of Hematite Concentrate by H[sub(2)] or CO 7.6.5.6 Derivation for Comparison of X-vs-t of a Compound with That of an Intermediate Phase as a Separate Reactant 7.6.6 Reduction by H[sub(2)] + CO Mixtures 7.6.7 Summary and Concluding Remarks Chapter 8 Development of Flash Ironmaking Technology – Tests in a Laboratory Flash Reactor 8.1 Laboratory Flash Reactor 8.1.1 Importance of Testing in Laboratory Flash Reactor 8.1.2 Apparatus 8.1.3 Experimental Procedure 8.2 Factors Affecting the Extent of Reduction 8.2.1 Particle Feeding Modes 8.2.2 Flame Configuration 8.2.3 Excess Driving Force – for H[sub(2)] + CO mixtures 8.2.4 Nominal Particle Residence Time 8.3 Experiments with Hydrogen 8.4 Experiments with Methane 8.5 Concluding Remarks Chapter 9 Development of Flash Ironmaking Technology – Operation of a Pilot-Plant-Scale Flash Reactor 9.1 Introduction 9.2 Facility 9.2.1 Reactor Vessel and Roof 9.2.2 Burners 9.2.3 Quench Tank 9.2.4 Flare Stack 9.2.5 Gas Valve Train 9.2.6 Off-Gas Analyzer 9.2.7 Water-Cooling System 9.2.8 Concentrate Feeding System 9.2.9 Gas Leak Detectors 9.2.10 Human–Machine Interface 9.3 Operation of the Mini-Pilot Flash Reactor 9.4 Results from Mini-Pilot Flash Reactor Runs 9.5 Difficulties During Operation 9.5.1 Water-Cooling System 9.5.2 Embedded Thermocouples in Reactor Vessel 9.5.3 Quench Tank Cracking 9.5.4 Sample Collection 9.6 Concluding Remarks Chapter 10 Development of Flash Ironmaking Technology – Computational Fluid Dynamics Design of Flash Ironmaking Reactors 10.1 Computational Fluid Dynamics Modeling of the Utah Laboratory Flash Reactor 10.1.1 Fluid Flow 10.1.2 Heat Transfer 10.1.3 Species Transport 10.1.4 Particle Tracking 10.1.5 Boundary Conditions 10.1.6 Numerical Details 10.1.7 Laboratory Flash Reactor Runs – with Hydrogen 10.1.7.1 Combustion Mechanism Validation 10.1.7.2 Temperature Validation 10.1.7.3 Reduction Degree 10.1.7.4 Velocity Field 10.1.7.5 Temperature Distribution 10.1.7.6 Species Distribution 10.1.7.7 Particle Residence Time 10.1.7.8 Concluding Remarks on Runs with Hydrogen 10.1.8 Laboratory Flash Reactor Runs – with Methane 10.1.8.1 Definition of Parameters 10.1.8.2 Governing Equations 10.1.8.3 Combustion Mechanism 10.1.8.4 Experimental Results 10.1.8.5 CFD Simulation Results 10.1.9 Concluding Remarks 10.2 Computational Fluid Dynamics Modeling of the Pilot-Plant-Scale Flash Reactor 10.2.1 Introduction 10.2.2 CFD Simulation 10.2.2.1 Incorporation of Natural Gas Combustion 10.2.3 Results and Discussion 10.2.4 Concluding Remarks 10.3 Optimization of Mini-Pilot Flash Reactor Operating Conditions with CFD 10.3.1 Realistic Boundary Conditions 10.3.2 Effect of the Inlet Oxygen to Natural Gas Ratio with the Same Total Gas Flow Rate 10.3.3 Effect of Total Gas Flow Rate with Constant Oxygen/Natural Gas Ratio 10.3.4 Comparison of the Simulated and the Equilibrium Gas Compositions 10.3.5 Profiles of Metallization Degree 10.3.6 Heat Loss to the Surroundings 10.4 Computational Fluid Dynamics Modeling – Design of Intermediate-Size Flash Ironmaking Reactors 10.4.1 Introduction 10.4.2 Geometries and Dimensions 10.4.3 Operating Conditions 10.4.4 Meshing and Mathematical Model 10.4.5 One-Burner Design 10.4.6 Four-Burner Design 10.4.7 Summary 10.5 Computational Fluid Dynamics Modeling – Design of Full-Scale Industrial Flash Ironmaking Reactors 10.5.1 Introduction 10.5.2 Model 10.5.3 Dimensions and Operating Conditions 10.5.4 Meshing 10.5.5 Mass-Weighted Average Gas Composition and Product Metallization at the Outlet 10.5.6 Profiles of Metallization Degree 10.5.7 Heat Loss 10.5.8 Concluding Remarks Chapter 11 Flash Ironmaking Flow Sheet Development and Process Analysis 11.1 Hydrogen-Based Flash Ironmaking Technology 11.1.1 Introduction 11.1.2 Flow Sheet Development and Process Simulation 11.1.3 Simulation Results 11.1.3.1 Material and Energy Balances 11.1.4 Summary on Hydrogen-Based Flash Ironmaking 11.2 Natural-Gas-Based Flash Ironmaking Technology – Reformerless Process 11.2.1 Introduction 11.2.2 Flow Sheet Development and Process Simulation 11.2.3 Material and Energy Balances 11.2.4 Summary on Reformerless Natural-Gas-Based Flash Ironmaking Technology 11.3 Natural-Gas-Based Flash Ironmaking Technology–Ironmaking Combined with Steam-Methane Reforming 11.3.1 Introduction 11.3.2 Flow Sheet Development and Process Simulation 11.3.2.1 Ironmaking Section 11.3.2.2 Steam-Methane Reforming Section 11.3.3 Material and Energy Balances 11.3.4 Summary on Natural-Gas-Based Flash Ironmaking Technology – Combined with Steam-Methane Reforming Chapter 12 Economic Analysis of Flash Ironmaking Technology 12.1 Introduction 12.2 Methods of Estimation for Economic Feasibility Analysis 12.2.1 Capital Cost Estimation 12.2.2 Operating Cost Estimation 12.2.2.1 Estimation Procedure of Net Present Value 12.2.2.2 Carbon Dioxide Emission Credit 12.3 Net Present Value Results and Sensitivity Analysis – Hydrogen-Based Flash Ironmaking 12.4 Net Present Value Results and Sensitivity Analysis – Natural-Gas-Based Flash Ironmaking 12.4.1 Capital Cost Estimation 12.4.2 Operating Cost Estimation 12.4.3 Summary of Net Present Value Estimation 12.4.4 Conclusions on Natural-Gas-Based Flash Ironmaking References Index