Voltage-Enhanced Processing of Biomass and Biochar (eBook)

Gerardo Diaz, PhD, is a Professor of Mechanical Engineering and Director of the Sustainable Plasma Gasification Lab at the University of California at Merced. He received his PhD in Mechanical Engineering from the University of Notre Dame in 2000.

Contributors xi

Preface xiii

Acknowledgments xv

Acronyms xvii

Introduction xix

1 Carbonaceous Material Characterization 1

1.1 Material Characterization 2

1.1.1 Thermophysical properties 3

1.1.2 Moisture Content 3

1.1.3 Ultimate and Proximate analysis 4

1.1.4 Dielectric and electrical properties 4

1.2 Biomass 6

1.3 Biochar 7

1.3.1 Surface area, cation exchange capacity, and pH 9

1.4 Activated carbon 11

1.5 Pyrolytic graphite 11

Bibliography 12

2 Conventional Processing Methods 21

2.1 Biomass Processing 22

2.1.1 Biomass Pyrolysis 23

2.1.2 Biomass Gasification 26

2.2 Biochar production and post processing 28

2.2.1 Biochar Activation 34

Bibliography 44

3 Introduction to Plasmas 49

3.1 Thermal Plasmas 50

3.1.1 Mathematical model 53

3.2 Non-thermal Plasmas 56

3.2.1 DC non-thermal electrical discharges 59

3.2.2 Dielectric barrier discharge 64

3.2.3 Pulsed discharges 65

3.2.4 Gliding arc 66

3.2.5 Microwave-induced discharges 67

3.3 Impedance matching 68

3.4 Discharges in liquids 71

3.4.1 Contact glow discharge electrolysis 72

3.4.2 Plasma electrolysis with AC power 76

3.4.3 Gliding arc in glycerol for hydrogen generation 77

Bibliography 78

4 Voltage-Enhanced Processing of Biomass 85

4.1 Biomass gasification with thermal plasma 86

4.1.1 Plasma parameters 87

4.1.2 Syngas composition 88

4.1.3 Energy balance 92

4.1.4 Temperature decay in plasma/biomass discharge 95

4.2 Dielectric breakdown of biomass 97

4.2.1 Biomass-in-the-loop 98

4.3 Biomass gasification with non-thermal plasma 99

4.3.1 Tar breakdown 100

4.3.2 Circuit configuration 104

4.3.3 Scaling up of the technology 107

Bibliography 107

5 Voltage-Enhanced Processing of Biochar 113

5.1 DC Power Applied to Biochar 114

5.1.1 Joule heating of biochar 114

5.1.2 Joule heating of activated carbon 118

5.1.3 Recent Trends in Mathematical modelling 150

5.2 Physical activation of biochar with non-thermal plasma 159

5.2.1 Plasma-steam activation 160

Bibliography 162

6 Numerical simulations 167

6.1 Background 167

6.2 Modeling approaches 168

6.2.1 Kinetic approach 169

6.2.2 Fluid model approach 172

6.3 Examples of non-thermal plasma modeling 175

6.3.1 Cathode fall of a DC glow discharge 176

6.3.2 RF plasma discharge 179

6.3.3 Plasma chemistry 185

Bibliography 191

7 Control of plasma systems 195

7.1 Control of thermal plasma torches 196

7.1.1 Dynamics 198

7.1.2 Control 201

7.2 Control of nonthermal plasma discharges 207

7.2.1 Plasma diagnostics 208

7.2.2 AI-based control 209

Bibliography 214