Energy conservation in the mechanical forest industries

Table of Contents

FAO FORESTRY PAPER 93

FOOD AND AGRICULTURE ORGANIZATION OF THE UNITED NATIONS
Rome, 1990

The designations employed and the presentation of material in this publication do not imply the expression of any opinion whatsoever on the part of the Food and Agriculture Organization of the United Nations concerning the legal status of any country, territory, city or area or of its authorities, or concerning the delimitation of its frontiers or boundaries.

M-30

ISBN 92-5-102912-1

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© FAO 1990

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Table of Contents

Foreword

Introduction

1. Descriptions of manufacturing processes

1.1 Introduction
1.2 Sawmilling

1.2.1 Log sorting and barking
1.2.2 Log sawing or breakdown
1.2.3 Sorting and grading
1.2.4 Drying
1.2.5 Regrading and surfacing

1.3 Plywood production

1.3.1 Log sorting, conditioning and barking
1.3.2 Peeling, reeling and clipping
1.3.3 Veneer drying
1.3.4 Assembly
1.3.5 Pressing
1.3.6 Finishing

1.4 Particleboard production

1.4.1 Particle preparation
1.4.2 Particle drying and screening
1.4.3 Blending and mat forming
1.4.4 Pressing
1.4.5 Board finishing

2. Energy consumption

2.1 Energy consumed by the industry
2.2 Energy supply

2.2.1 Electric power
2.2.2 Heat
2.2.3 Heat applications
2.2.4 Secondary energy

2.3 Pattern of energy input

2.3.1 Input variations

2.4 Specific energy consumption

2.4.1 Factors which influence energy consumption
2.4.2 Specific energy requirements

2.5 Proportional energy utilization in the manufacturing process

3. Government energy conservation policies

3.1 Introduction
3.2 Common policy aims
3.3 A selection of adopted national energy policies
3.4 Energy policies of selected developed countries

3.4.1 United Kingdom
3.4.2 Canada
3.4.3 Sweden
3.4.4 Finland
3.4.5 United States
3.4.6 France
3.4.7 Germany
3.4.8 Greece

3.5 Suggested recommendations for Government action

3.5.1 Expected benefits

4. Managing an energy conservation programme

4.1 Introduction

4.1.1 Fuel price increases
4.1.2 Benefits of energy conservation
4.1.3 Some examples of reasons held for caution

4.2 Role of management

4.2.1 Energy manager

4.3 Staff development, training and motivation
4.4 Investment appraisal
4.5 Strategic approach to planning

4.5.1 Seeking advice
4.5.2 Energy audit

5. The role of design and equipment selection

5.1 Introduction
5.2 Plant layout, building design and equipment selection

5.2.1 Wood-yard and plant layout
5.2.2 Buildings
5.2.3 Equipment selection

5.3 Materials handling

5.3.1 Log handling, washing and barking
5.3.2 Raw materials for particleboard manufacture
5.3.3 Conveying systems
5.3.4 Importance of buffer stocks
5.3.5 Mobile equipment

5.4 Log breakdown, peeling and particle reduction

5.4.1 Sawing
5.4.2 Veneer peeling
5.4.3 Peeler-log conditioning
5.4.4 Particle reduction

5.5 Drying

5.5.1 Kiln drying of lumber
5.5.2 Air drying and pre-drying
5.5.3 Veneer drying
5.5.4 Particle drying
5.5.5 Heat recovery

5.6 Hot pressing

5.6.1 Pre-pressing

5.7 Primary finishing
5.8 Services

5.8.1 Boiler plant
5.8.2 Steam and condensate system
5.8.3 Electrical power
5.8.4 Lighting
5.8.5 Compressed air

6. The potential use of wood residues for energy generation

6.1 Introduction
6.2 Sources of available wood residues

6.2.1 Forest residues
6.2.2 Mill-site generated wood waste
6.2.3 Integrated production
6.2.4 Alternative uses of residues

6.3 The fuel value of wood residues

6.3.1 Heating value
6.3.2 Effect of moisture content and particle size on heat values

6.4 The preparation of wood waste fuel

6.4.1 Collection and handling
6.4.2 Storage
6.4.3 Size reduction and screening
6.4.4 Fuel drying
6.4.5 Densification

6.5 Applications for waste-based energy
6.6 Combustion

6.6.1 Firetube and watertube boilers
6.6.2 Pile burners
6.6.3 Suspension and cyclone burners
6.6.4 Fluidized-bed combustors

6.7 Cogeneration

6.7.1 Restrictive regulations and penalties
6.7.2 Economic considerations

APPENDIX I

APPENDIX II

APPENDIX III

APPENDIX IV

APPENDIX V

APPENDIX VI

REFERENCES