Boiler Control Systems Engineering is designed for anyone working with boilers, including utility managers, power plant managers, control systems engineers, maintenance technicians and operators. It primarily focuses on water-tube boilers with induced draft (ID) and forced draft (FD) fans, as well as those with only FD fans. The content can also be applied to any fuel-fired steam generator. Although other books on boiler control exist, they do not cover the detailed engineering aspects of control systems and the setup of various control functions.
This book provides specific examples of boiler control, including configuration and tuning, valve sizing and transmitter specifications. This expanded and updated Second Edition features drum-level compensation equations, additional piping and instrumentation diagrams (P&IDs) and examples of permissive start-up and tripping logic for gas, oil and coal-fired boilers. It also covers different control schemes for furnace draft management. NFPA 85 Code 2007 control system requirements are included, along with illustrated examples of coal-fired boilers and information on the latest ISA-77 standards.
Table of Contents:
Chapter 1 Boiler Fundamentals 1
Basic Boilers 1
Boiler Components 2
Furnace 2
Fans 2
Windbox 2
Flue Gas Heat Exchangers 2
Combustion Air Preheater 5
Economizer 5
Superheater 6
Boiler Drums 6
Piping and Instrument Diagrams (P&IDs) 7
Design Basis Check List 8
Chapter 2 Control of Boilers 11
Control Strategies 11
Bumpless Transfer 11
Simple Feedback Control 11
Feedforward plus Feedback Control 12
Cascade Control 13
Ratio Control 14
Feedforward Control 14
Controller Tuning 15
Determining Gain, Reset, and Derivative 17
Gain vs Proportional Band (PB) 19
Controller Actions 19
Controller Actions Setup 22
The Effects on Tuning 22
Calibration Effect on Gain 22
Transmitters 22
Redundancy 23
Interlock Circuitry 23
Final Control Elements 24
Chapter 3 Furnace Draft 25
Pressure Fired Boilers 25
Balanced Draft Boiler Fans 26
Furnace Pressure Control 26
Summer 30
Chapter 4 Feedwater 35
Once-Through Boilers 35
Drum Level Feedwater Control 36
Transmitters 41
Shrink and Swell 42
Single Element Level Control 44
Two Element Level Control 44
Three Element Level Control 48
Control System Configuration 48
Summer 48
Chapter 5 Coal Fired Boilers 51
Pulverized Coal Fired Boilers 51
Raw Coal and Feeder 54
Stoker Boilers 56
Cyclone Boiler 56
Graphics: Pulverizer Coal Boiler 59
Chapter 6 Fuel and Air Control 67
Fuel and Air Control Gas Oil 72
Fuel and Air Control Characterization 74
Excess Air to Oxygen 76
Multiple Fuel Control 77
Oxygen (O2) Trim Control 78
Multiple Boilers 80
Chapter 7 Steam Temperature 81
Three Element Level Control 83
Chapter 8 Burner Management Systems 91
Burner Management System (BMS) Control 91
NFPA 85 Code 2007 91
Boiler Control and Operating Documentation 92
Combustion Control 92
Purge Control 93
Requirement for Independence of Control (Hardware/Software) 94
Flame Detection 95
Flame Monitoring and Tripping System (Multiple Burner Boilers) 96
Flame Tripping Validation 97
Examples of Permissive Starting Logic and Protective Tripping Logic 109
Chapter 9 Environment 111
NOx and NOx Control 111
Excess Air to Oxygen 113
Boiler Efficiency Computations 115
Input/Output Example 115
Chapter 10 Control Valve Sizing 117
Valve Characteristics 117
Valve Characteristic Graph 118
Recommended Velocities 118
Valve Sizing for Different Control Media 119
Control Valve Sizing Calculations 119
Gas Valve Sizing 120
Chapter 11 Steam Temperature Control 123
Purpose 123
Introduction 123
Principles and Methods of Transient Superheat Steam 124
Temperature Control
NOx Control 126
Redundancy 126
Reset Windup Prevention 126
Advanced Steam Temperature Control 127
Acronyms 129
Appendix A 131
Appendix B 141
Appendix C 179
Appendix D 181
Bibliography 187
References 189
Kraft Pulp Mill 195
Index 197
About the Author :
Jerry Gilman's career has spanned more than 37 years with Procter & Gamble (P&G), and its subsidiaries. As a process control systems engineer for P&G, Gilman was dedicated to improving control systems and implementing new technology in numerous product areas at P&G in the US and foreign countries. One of his areas of expertise has been with boiler control systems engineering: improving efficiency, conserving energy, and working as a primary troubleshooter on boilers and other combustion systems.
A licensed professional engineer, Jerry Gilman currently provides training for ISA (International Society of Automation) and consulting to utility plants, industrial power plants and engineering contractors. This includes performing startups, tuning, and troubleshooting more than a hundred boilers and combustion systems such as dryers, roasters, and ovens. Gilman's expertise in fuels and combustion control ranges from finding solutions for new unit applications to retrofitting existing installations in order to save fuel, change fuels, or improve overall control. He has applied his experience in combustion testing and energy utilization to help simplify boiler performance monitoring techniques and methods. His approaches are easy to understand and use effectively.
Jerry Gilman is the developer of the "ISA Boiler Control Systems Engineering" and "ISA Burner Management Systems Engineering" training courses. He has been a guest speaker on boiler control, burner management, and boiler safety issues at various ISA section meetings and other user groups and seminars. Additionally, he was a technical advisor for "Win Boiler Sim," a PC-based boiler training program developed by Len Klochek and sold through ISA.
Jerry Gilman is an active member on the following ISA Standards Committees: ISA84 Programmable Electronic Systems (PES) for Use in Safety Applications; ISA84 Burner Management System Working Group; and ISA77 Fossil Fuel Power Plant Standards.
