Page 9 - Biomass Gasification, Pyrolysis And Torrefaction Practical Design and Theory

viii Contents

2.3.4 Torrefier Cost 38
2.3.5 Pyrolyzer Cost 39
2.3.6 Comparison of Capital Costs 39
2.4 Financial Analysis 40
2.4.1 Capital Cost Adjustment for Size and Time 40
2.4.2 Capital Requirement 42
2.4.3 Operation and Maintenance Cost 43
Symbols and Nomenclature 46

3. Biomass Characteristics 47
3.1 Introduction 47
3.2 What Is Biomass? 47
3.2.1 Biomass Formation 48
3.2.2 Types of Biomass 49
3.3 Structure of Biomass 54
3.3.1 Structure of Wood 55
3.3.2 Constituents of Biomass Cells 56
3.4 General Classification of Fuels 60
3.4.1 Atomic Ratio 60
3.4.2 Relative Proportions of Lignocellulosic Components 61
3.4.3 Ternary Diagram 62
3.5 Properties of Biomass 63
3.5.1 Physical Properties 63
3.5.2 Thermodynamic Properties 67
3.6 Composition of Biomass 73
3.6.1 Ultimate Analysis 73
3.6.2 Proximate Analysis 75
3.6.3 Thermogravimetric Analysis 78
3.6.4 Bases of Expressing Biomass Composition 78
3.6.5 Heating Value of Fuel 80
3.6.6 Stoichiometric Calculations for Complete Combustion 82
3.6.7 Composition of the Product Gas of Gasification 83
Symbols and Nomenclature 84

4. Torrefaction 87
4.1 Introduction 87
4.2 What Is Torrefaction? 87
4.2.1 Pyrolysis, Carbonization, and Torrefaction 89
4.3 Carbonization 92
4.3.1 Charcoal Fuel 92
4.3.2 Activated Charcoal 93
4.3.3 Biocoke 93
4.3.4 Biochar 94
4.4 Torrefaction Process 94
4.4.1 Heating Stages 96
4.4.2 Mechanism of Torrefaction 99
4.4.3 Effect of Design Parameters on Torrefaction 101