Supercritical Water

Preface ix

List of Acronyms and Symbols xiii

1 Introduction 1

1.1 Phase Diagrams of Single Fluids / 1

1.2 The Critical Point / 3

1.3 Supercritical Fluids as Solvents / 5

1.4 Gaseous and Liquid Water / 8

1.5 Near-Critical Water / 15

1.6 Summary / 17

2 Bulk Properties of SCW 22

2.1 Equations of State(EoS) / 22

2.1.1 PVT Data for SCW / 22

2.1.2 Classical Equations of State of SCW / 24

2.1.3 Scaling Equations of State for SCW / 26

2.1.4 EoS of Supercritical Heavy Water / 29

2.2 Thermophysical Properties of SCW / 30

2.2.1 Heat Capacity / 30

2.2.2 Enthalpy and Entropy / 32

2.2.3 Sound Velocity / 34

2.3 Electrical and Optical Properties / 34

2.3.1 Static Relative Permittivity / 34

2.3.2 Electrical Conductivity / 37

2.3.3 Light Refraction / 38

2.4 Transport Properties / 39

2.4.1 Viscosity / 39

2.4.2 Self-Diffusion / 41

2.4.3 Thermal Conductivity / 42

2.5 Ionic Dissociation of SCW / 44

2.6 Properties Related to the Solvent Power of SCW / 47

2.7 Summary / 49

3 Molecular Properties of SCW 57

3.1 Diffraction Studies of SCW Structure / 60

3.1.1 X-Ray Diffraction Studies of SCW Structure / 61

3.1.2 Neutron Diffraction Studies of SCW Structure / 62

3.2 Computer Simulations of SCW / 66

3.2.1 Monte Carlo Simulations / 67

3.2.2 Molecular Dynamics Simulations / 70

3.3 Spectroscopic Studies of SCW / 74

3.3.1 Infrared Absorption Spectroscopy / 74

3.3.2 Raman Scattering Spectroscopy / 77

3.3.3 Nuclear Magnetic Resonance / 79

3.3.4 Dielectric Relaxation Spectroscopy / 82

3.4 The Extent of Hydrogen Bonding in SCW / 83

3.5 The Dynamics of Water Molecules in SCW / 90

3.6 Summary / 92

4 SCW as a “Green” Solvent 100

4.1 Solutions of Gases in SCW / 101

4.1.1 Phase Equilibria / 101

4.1.2 Interactions in the Solutions / 104

4.2 Solutions of Organic Substances in SCW / 106

4.2.1 Phase Equilibria / 106

4.2.2 Interactions in the Solutions / 111

4.3 Solutions of Salts and Ions in SCW / 115

4.3.1 Solubilities of Salts and Electrolytes / 115

4.3.2 Thermodynamic Properties / 121

4.3.3 Transport Properties / 123

4.3.4 Ion Association in SCW / 129

4.3.5 Ion Hydration in SCW / 134

4.4 Binary Mixtures of Cosolvents with SCW / 138

4.5 Summary / 141

5 Applications of SCW 151

5.1 Conversion of Organic Substances to Fuel / 152

5.1.1 Conversion to Hydrogen and Natural Gas / 152

5.1.2 Conversion to Liquid Fuel / 156

5.2 Supercritical Water Oxidation / 157

5.2.1 General Aspects of SCWO Process / 158

5.2.2 Examples of SCWO Applications / 160

5.3 Uses of SCW in Organic Synthesis / 162

5.4 Uses in Powder Technology of Inorganic Substances / 164

5.5 Geothermal Aspects of SCW / 166

5.6 Application of SCW in Nuclear Reactors / 169

5.7 Corrosion Problems with SCW / 171

5.8 Summary / 174

Author Index 183

Subject Index 199