Power Plant Instrumentation and Control Handbook

A Guide to Thermal Power Plants

Swapan Basu, Ajay Kumar Debnath

• Publisher: Academic Press
• Year: 2014
• eBook ISBN: 9780128011737
• Topic: Technology & Engineering
• Subtopic: Industrial Engineering
• Index: Technology & Engineering

The book discusses instrumentation and control in modern fossil fuel power plants, with an emphasis on selecting the most appropriate systems subject to constraints engineers have for their projects. It provides all the plant process and design details, including specification sheets and standards currently followed in the plant. Among the unique features of the book are the inclusion of control loop strategies and BMS/FSSS step by step logic, coverage of analytical instruments and technologies for pollution and energy savings, and coverage of the trends toward filed bus systems and integration of subsystems into one network with the help of embedded controllers and OPC interfaces. The book includes comprehensive listings of operating values and ranges of parameters for temperature, pressure, flow, level, etc of a typical 250/500 MW thermal power plant. Appropriate for project engineers as well as instrumentation/control engineers, the book also includes tables, charts, and figures from real-life projects around the world. - Covers systems in use in a wide range of power plants: conventional thermal power plants, combined/cogen plants, supercritical plants, and once through boilers - Presents practical design aspects and current trends in instrumentation - Discusses why and how to change control strategies when systems are updated/changed - Provides instrumentation selection techniques based on operating parameters. Spec sheets are included for each type of instrument - Consistent with current professional practice in North America, Europe, and India

Chapter I

Introduction

Abstract

Authors are associated with the Instrumentation System of Power Plants for over decades and are still in touch with modern technology. This book is the outcome of their experiences to benefit practicing engineers and students associated with power plants. Power Plant concepts are based on Laws of Thermodynamics depicting the relations among Heat, Work, property of system, Specific Weight / Volume, Path, Process, etc. Definitions of different types of Energy, Work, Boyle’s Law & Charles Law with general and combined equations, Avogadro’s Law / Hypothesis, Universal Gas Constant, Enthalpy, Entropy, Rankin and other cycles are touched upon in this Chapter along with Pressure – Volume and Temperature-Entropy Diagram for steam, different types of Boilers, Turbines, Condensers and Regenerative cycles. These recapitulations have been done at the beginning to enable reader to refresh basic knowledge on power plants.

Keywords

Power Plant Hand Book; Heat & Work; Laws of Thermodynamics; Rankin cycle; Enthalpy; Entropy; Steam & Gas Turbine

1. Introduction

The authors of this book have been associated with the Instrumentation and Control System of Modern Power Plants for more than two decades while working with a leading consulting firm. They are still in touch with modern technology by associating with the engineering and consultancy activities of ongoing projects. We wanted to document their extended experience in the form of a reference book so that professional engineers, working engineers in power plants, and students could benefit from the knowledge gathered during their tenure.

There are so many valuable and good books available on a variety of subjects related to power plants about boilers, turbines, and generators and their subsystems, but it is very difficult to get a single book or single volume of a book to cater to the equipment, accessories, or items along with the instrumentation and control systems associated with them. In this book, there is a very brief description of the system and equipment along with diagrams for a cursory idea about the entire plant. Up-to-date piping and instrumentation diagrams (P&IDs) are included to better understand the tapping locations of measuring and control parameters of the plant.

Various types of instruments, along with sensors, transmitters, gauges, switches, signal conditioner/converter, etc., have been discussed in depth in dedicated chapters, whereas special types of instruments are covered in separate chapters. Instrument data sheets or specification sheets are included so that beginners may receive adequate support for preparing the documents required for their daily work.

The control system chapters VIII, IX and X incorporate the latest control philosophy that has been adopted in several power stations.

This book mainly emphasizes subcritical boilers, but a separate appendix is provided on supercritical boilers because of their economic and low-pollution aspects, which create a bigger demand and need than do conventional subcritical boilers.

It is hoped that this book may help students and/or those who perform power plant-oriented jobs.

2. Fundamental Knowledge about Basic Process

Power plant concepts are based on the Laws of Thermodynamics, which depict the relationship among heat, work, and various properties of the systems. All types of energy transformations related to various systems (e.g., mechanical, electrical, chemical etc.) may fall under the study of thermodynamics and are basically founded on empirical formulae and system and/or process behavior. A thermodynamic system is a region in space on control volume or mass under study toward energy transformation within a system and transfer of energy across the boundaries of the system.

2.0. Ideas within and Outside the System

1. Surrounding: Space and matter outside the thermodynamic system.

2. Universe: Thermodynamic system and surroundings put together.

3. Thermodynamic systems:

a. Closed: Only energy may cross the boundaries with the mass remaining within the boundary.

b. Open: Transfer of mass takes place across the boundary.

c. Isolated: The system is isolated from its surrounding and no transfer of mass or energy takes place across the boundary.

4. State: It is the condition detailed in such a way that one state may be differentiated from all other states.

5. Property: Any observable characteristics measurable in terms of numbers and units of measurement, including physical qualities such as pressure, temperature, flow, level, location, speed, etc. The property of any system depends only on the state of the system and not on the process by which the state has been achieved.

a. Intensive: Does not depend on the mass of the system (e.g., pressure, temperature, specific volume, and density).

b. Extensive: Depends on the mass of the system (i.e., volume).

6. Specific weight: The weight density (i.e., weight per unit volume).

7. Specific volume: Volume per unit mass.

8. Pressure: Force exerted by a system per unit area of the system.

9. Path: Thermodynamic system passes through a series of states.

10. Process: Where various changes of state take place.

11. Cyclic process: The process after various changes of state complete their journey at the same initial point of state.

2.0.1. Zeroeth Law of Thermodynamics

“If two systems are both in thermal equilibrium with a third system, they are in thermal equilibrium with each other.” Thermal equilibrium displays no change in the thermodynamic coordinates of two isolated systems brought into contact; thus, they have a common and equal thermodynamic property called temperature. With the help of this law, the measurement of temperature was conceived. A thermometer uses a material’s basic property, which changes with temperature.

2.0.1.1. Energy

“The definition in its simplest form is capacity for producing an effect.” There are a variety of classifications for energy.

1. Stored energy may be described as the energy contained within the system's boundaries. There are various forms, such as:

a. Potential

b. Kinetic

c. Internal

2. Energy in transition may be described as e...

Table of contents

• Cover image
• Title page
• Table of Contents
• Copyright
• Dedication
• Foreword
• Preface
• Acknowledgments
• Chapter I. Introduction
• Chapter II. Main Equipment
• Chapter III. Plant P&ID Discussions
• Chapter IV. General Instruments
• Chapter V. Special Instrument
• Chapter VI. Final Control Element
• Chapter VII. Intelligent Control System
• Chapter VIII. Boiler Control System
• Chapter IX. Turbo Generator Control System
• Chapter X. Coordinated Control System
• Chapter XI. Balance of Plant Control System
• Chapter XII. Installation Practices
• Appendix I. Process and Mechanical Standard Table
• Appendix II. Electrical Data and Tables
• Appendix III. ISA Standard, Materials, Human Engineering, and Control Room
• Appendix IV. Network Control and Communication
• Appendix V. Super/Ultra Super Critical Power Plants
• Appendix VI. Integrated Gasifier and Combined Cycle Plant (Pollution Control)
• Appendix VII. A Few Operational Features of the Unit
• Index