Computer simulation is the key to comprehending and controlling the full-scale industrial plant used in the chemical, oil, gas and electrical power industries. Simulation of Industrial Processes for Control Engineers shows how to use the laws of physics and chemistry to produce the equations to simulate dynamically all the most important unit operations found in process and power plant.
The book explains how to model chemical reactors, nuclear reactors, distillation columns, boilers, deaerators, refrigeration vessels, storage vessels for liquids and gases, liquid and gas flow through pipes and pipe networks, liquid and gas flow through installed control valves, control valve dynamics (including nonlinear effects such as static friction), oil and gas pipelines, heat exchangers, steam and gas turbines, compressors and pumps, as well as process controllers (including three methods of integral desaturation). The phenomenon of markedly different time responses ("stiffness") is considered and various ways are presented to get around the potential problem of slow execution time. The book demonstrates how linearization may be used to give a diverse check on the correctness of the as-programmed model and explains how formal techniques of model validation may be used to produce a quantitative check on the simulation model's overall validity.
The material is based on many years' experience of modelling and simulation in the chemical and power industries, supplemented in recent years by university teaching at the undergraduate and postgraduate level. Several important new results are presented. The depth is sufficient to allow real industrial problems to be solved, thus making the book attractive to engineers working in industry. But the book's step-by-step approach makes the text appropriate also for post-graduate students of control engineering and for undergraduate students in electrical, mechanical and chemical engineering who are studying process control in their second year or later.
"With his book, Professor Thomas has provided a major contribution to the modelling of major unit processes which are found in the chemical, oil-and -gas and power generation industries....the book represents a major achievement and can be strongly recommended."
IMechE - Proc. Inst. Mech. Engrs. October 2001
'..highly recommended to anyone involved in mathematical simulation for any purpose..'
Nuclear Energy, October 2000.
"Professor Thomas has produced a much-needed work in the field of modeling and simulation of industrial systems...It is most apparent that a practitioner with many years of experience has written this book....a most valuable addition to any technical library..It is a useful reference not just for control engineers but for mechanical and chemical engineers as well." - Intech (ISA Journal) , August 2000
"Engineers simulating industrial processes commonly found in the chemical, nuclear and oil industries will find this book essential to their work....this book will be of considerable importance to all engineers interested in the mathematical modelling and simulation of industrial processes. The book is clearly the most comprehensive and up-to-date treatise currently available on this important topic."
IEE Computing & Control Engineering Journal, April 2000.
"This is a significant book for those serious about learning how to produce good dynamic simulations of process plant...it shows how to use good science to derive models of the appropriate complexity to suit the particular problem....It is recommended both for those wishing to learn about the subject, and for the experienced who need to find out how to model a particular piece of equipment."
Measurement and Control, Nov. 1999
"Professor Thomas and his publishers are to be congratulated for producing such a useful resource text."
The Nuclear Engineer, Vol. 41, No. 1, 2000
"This book should be of great interest to those addressed in the title...It is difficult to think of a comparable source of explanation and information in this field."
Dr Alex Thompson, HMS Sultan
"it is rare to find a modern engineering textbook which combines theory and practice to such a useful effect. Professor Thomas is to be congratulated on providing such an outstanding work."
Dr Andrew Eadie, Glasgow Caledonian University.
Foreword | p. xv |
Notation | p. vxii |
Introduction | p. 1 |
Fundamental concepts of dynamic simulation | p. 5 |
Introduction | p. 5 |
Building up a model of a simple process-plant unit: tank liquid level | p. 5 |
The general form of the simulation problem | p. 7 |
The state vector | p. 8 |
Model complexity | p. 9 |
Distributed systems: partial differential equations | p. 10 |
The problem of stiffness | p. 12 |
Tackling stiffness in process simulations: the properties of a stiff integration algorithm | p. 15 |
Tackling stiffness in process simulations by modifications to the model | p. 16 |
Solving nonlinear simultaneous equations in a process model: iterative method | p. 17 |
Solving nonlinear simultaneous equations in a process model: the Method of Referred Derivatives | p. 18 |
Bibliography | p. 20 |
Thermodynamics and the conservation equations | p. 21 |
Introduction | p. 21 |
Thermodynamic variables | p. 21 |
Specific heats of gases | p. 22 |
Conservation of mass in a bounded volume | p. 23 |
Conservation of energy in a fixed volume | p. 24 |
Effect of volume change on the equation for the conservation of energy | p. 26 |
Conservation of energy equation for a rotating component | p. 26 |
Conservation of mass in a pipe | p. 27 |
Conservation of energy in a pipe | p. 28 |
Conservation of momentum in a pipe | p. 30 |
Bibliography | p. 31 |
Steady-state incompressible flow | p. 32 |
Introduction | p. 32 |
The energy equation for general steady-state flow | p. 32 |
Incompressible flow | p. 33 |
Magnitude of the Fanning friction factor, f | p. 34 |
Frictionally resisted, incompressible flow through a real pipe | p. 35 |
Pressure drop due to level difference | p. 36 |
Frictional pressure drop | p. 36 |
Pressure drop due to bends and fittings | p. 37 |
Pressure drop at pipe outlet | p. 37 |
Pressure drop at pipe inlet | p. 39 |
Overall relationship between mass flow and pressure difference | p. 40 |
Bibliography | p. 40 |
Flow through ideal nozzles | p. 41 |
Introduction | p. 41 |
Steady-state flow in a nozzle | p. 41 |
Maximum mass flow for a polytropic expansion | p. 45 |
Sonic flow | p. 45 |
Comparison between flow formulae | p. 47 |
Bibliography | p. 49 |
Steady-state compressible flow | p. 50 |
Introduction | p. 50 |
General overview of compressible pipe-flow | p. 50 |
Frictionally resisted, adiabatic flow inside the pipe | p. 51 |
Solution sequence for compressible flow through a pipe | p. 55 |
Determination of the friction factor, f | p. 56 |
Determination of the effective length of the pipe | p. 56 |
Sample calculation | p. 56 |
Explicit calculation of compressible flow | p. 57 |
Example using the long-pipe approximation | p. 58 |
Bibliography | p. 59 |
Control valve liquid flow | p. 60 |
Introduction | p. 60 |
Types of control valve | p. 60 |
Pressure distribution through the valve | p. 61 |
Liquid flow through the valve | p. 62 |
Cavitation and choking in liquid flow | p. 63 |
Relationship between valve capacity at part open and capacity at full open | p. 64 |
The valve characteristic | p. 64 |
Velocity-head loss across the value | p. 65 |
Bibliography | p. 67 |
Liquid flow through the installed control valve | p. 68 |
Introduction | p. 68 |
Liquid flow through an installed valve | p. 68 |
Choking during liquid flow | p. 69 |
Cavitation during liquid flow | p. 70 |
Example: calculation of liquid flow | p. 70 |
Control valve gas flow | p. 74 |
Introduction | p. 74 |
Representing the first section of the control valve as a nozzle | p. 74 |
The relationship between throat ratio and the valve pressure ratio at high valve pressure ratios, p2/p1 | p. 76 |
Deriving a value for throat area, A[subscript t] from the limiting gas conductance, C[subscript g] | p. 77 |
Correlation of the friction coefficient at high-pressure ratios with the cavitation coefficient | p. 77 |
The relationship between throat and valve pressure ratios when the valuve pressure ratio is low | p. 78 |
Relating throat and exit pressure ratios throughout the pressure ratio range | p. 80 |
Flow at partial valve openings | p. 81 |
Summary of the nozzle-based model for gas flow through the control valve | p. 82 |
Worked example using the nozzle-based calculational model | p. 83 |
Other models for gas flow | p. 85 |
Bibliography | p. 88 |
Gas flow through the installed control valve | p. 90 |
Introduction | p. 90 |
Gas flow through an installed valve - Velocity-Head Implicit Method (VHIM) | p. 90 |
Gas flow through an installed valve - Smoothed Velocity-Head Implicit Method (SVHIM) | p. 94 |
Gas flow through an installed valve - Average Specific Volume Approximation Method (ASVAM) | p. 97 |
Example: calculation of gas flow | p. 98 |
Discussion | p. 106 |
Accumulation of liquids and gases in process vessels | p. 108 |
Introduction | p. 108 |
Accumulation of liquid in an open vessel at constant temperature | p. 108 |
Accumulation of gas in a vessel at constant temperature | p. 108 |
Use of kilogram-moles in modelling the accumulation of a mixture of gases | p. 110 |
Gas accumulation with heat exchange | p. 112 |
Liquid and gas accumulation with heat exchange | p. 114 |
Two-phase systems: boiling, condensing and distillation | p. 117 |
Introduction | p. 117 |
Description of single component boiling/condensing: boiling model | p. 117 |
Functions used in the modelling of vapour--liquid equilibrium | p. 120 |
Application of the boiling model to a steam drum and recirculation loop | p. 120 |
Continuous distillation in a distillation column | p. 122 |
Mathematical model of the distillation plate | p. 123 |
Functions used in the modelling of the distillation plate | p. 130 |
Modelling the distillation column as a whole | p. 132 |
Bibliography | p. 134 |
Chemical reactions | p. 135 |
Introduction | p. 135 |
The reaction at the molecular and kilogram-mole levels | p. 135 |
Reaction rate relationship for the different chemical species in the reaction | p. 136 |
Reaction rates | p. 137 |
Generalization for multiple reactions | p. 137 |
Conservation of mass in a bounded volume | p. 138 |
Conservation of energy in a fixed volume | p. 139 |
The internal energy of reaction and the enthalpy of reaction | p. 140 |
The effect of temperature on [Delta]U and [Delta]H | p. 142 |
Continuous reaction in a gas reactor | p. 143 |
Modelling a Continuous Stirred Tank Reactor (CSTR) | p. 146 |
Bibliography | p. 151 |
Turbine nozzles | p. 152 |
Introduction | p. 152 |
Velocity and enthalpy relationships in a turbine nozzle: nozzle efficiency | p. 152 |
Dependence of the polytropic exponent on nozzle efficiency | p. 153 |
Effect of nozzle efficiency on nozzle velocity | p. 155 |
Using the concept of stagnation to account for non-neglible inlet velocities | p. 156 |
Sonic flow | p. 157 |
The convergent-only nozzle | p. 158 |
The convergent--divergent nozzle | p. 161 |
Bibliography | p. 171 |
Steam and gas turbines | p. 172 |
Introduction | p. 172 |
The turbine stage | p. 172 |
Stage efficiency and the stage polytropic exponent | p. 173 |
Reaction | p. 174 |
Mid-stage pressure; nozzle discharge velocity; stage mass flow | p. 176 |
Design conditions in an impulse blade | p. 176 |
Off-design conditions in an impulse stage: blade efficiency and stage outlet velocity in the absence of blade and nozzle inlet loss | p. 178 |
Loss ofkinetic energy caused by off-design angles of approach to moving and fixed blades | p. 179 |
Off-design conditions in an impulse blade: typical corrections for kinetic energy losses | p. 181 |
50% reaction stage: the design of the fixed blades (nozzles) and the moving blades | p. 181 |
Blade efficiency at design conditions for a 50% reaction stage | p. 183 |
Blade efficiency at off-design conditions for a 50% reaction stage | p. 185 |
The polytropic exponent for saturated steam | p. 187 |
Calculation sequence for turbine simulation | p. 187 |
Bibliography | p. 189 |
Steam and gas turbines: simplified model | p. 190 |
Introduction | p. 190 |
The effect of neglecting interstage velocities in modelling a real turbine stage: the approximate equivalence of kinetic energy and enthalpy at nozzle inlet | p. 190 |
Stage efficiency for an impulse stage | p. 191 |
Stage efficiency for a reaction stage | p. 192 |
Evaluation of downstream enthalpies following isentropic and frictionally resisted expansions | p. 193 |
Analytic functions linking entropy and enthalpy for saturated and superheated steam | p. 196 |
Specific volume at stage outlet | p. 199 |
Simplifying the calculation of mass flow | p. 199 |
Calculation sequence for the simplified turbine model | p. 201 |
Bibliography | p. 203 |
Turbo pumps and compressors | p. 204 |
Introduction | p. 204 |
Applying dimensional analysis to centrifugal and axial pumps | p. 204 |
Pump characteristic curves | p. 207 |
Pump dynamics | p. 209 |
Calculating the flow pumped through a pipe | p. 210 |
Rotary compressors | p. 211 |
Compressor characteristics based on polytropic head | p. 212 |
Compressor characteristics based on pressure ratio | p. 216 |
Computing the performance of the complete compressor | p. 218 |
Bibliography | p. 220 |
Flow networks | p. 221 |
Introduction | p. 221 |
Simple parallel networks | p. 221 |
Simple series network | p. 222 |
Complex networks | p. 223 |
Strategy for solving flow networks using iterative methods | p. 224 |
Modifying the flow equations to speed up the Newton--Raphson method | p. 225 |
Solving the steady-state flow network using the Method of Referred Derivatives | p. 229 |
Worked example using the Method of Referred Derivatives: liquid flow network | p. 230 |
Avoiding problems at flow reversal with the Method of Referred Derivatives | p. 235 |
Liquid networks containing nodes with significant volume: allowing for temperature changes | p. 236 |
Bibliography | p. 238 |
Pipeline dynamics | p. 239 |
Introduction | p. 239 |
Dynamic equations for a pipeline: the full equations | p. 239 |
Development of the equation for conservation of mass | p. 239 |
Development of the equation for conservation of momentum | p. 240 |
Applying the Method of Characteristics to pipeline dynamics | p. 240 |
Interfacing the Method-of-Characteristics pipeline model to the rest of process simulation: boundary conditions | p. 243 |
Correcting the speed of sound for the elasticity of the pipe material | p. 250 |
Example of pipeline flow using the Method of Characteristics | p. 251 |
Finite differences | p. 254 |
Bibliography | p. 255 |
Distributed components: heat exchangers and tubular reactors | p. 256 |
Introduction | p. 256 |
General arrangement of a shell-and-tube heat exchanger | p. 256 |
Equations for flow in a duct subject to heat exchange | p. 257 |
Equation for liquid flow in a duct subject to heat exchange | p. 258 |
Equation for gas flow in a duct subject to heat exchange | p. 258 |
Application of the duct equations to the tube-side fluid | p. 259 |
Application of the duct equations to the shell-side fluid | p. 259 |
Equations for the tube wall and the shell wall | p. 260 |
Solving the heat exchanger equations using spatial finite differences | p. 261 |
The tubular reactor | p. 262 |
Mass balance for the gas flowing through the catalyst bed | p. 263 |
Energy balance for the gas flowing through the catalyst bed | p. 263 |
Solving the temperature and conversion equations using finite differences | p. 266 |
Bibliography | p. 267 |
Nuclear reactors | p. 268 |
Introduction | p. 268 |
General description of a nuclear reactor | p. 268 |
The process of nuclear fission | p. 269 |
Delayed neutrons | p. 270 |
Reactor multiplication factor, k | p. 271 |
Absorption of neutrons and the production of prompt neutrons | p. 272 |
Overall neutron balance | p. 273 |
The balance for delayed neutron precursors | p. 273 |
Summary of neutron kinetics equations; reactor power | p. 274 |
Values of delayed neutron parameters and the problem of stiffness | p. 274 |
Relationship between neutron density, neutron flux and thermal power | p. 275 |
Spatial variations in neutron flux and power: centre-line and average reactor flux | p. 276 |
Flux and power in axial segments of the reactor core | p. 277 |
Calculating the temperature of the fuel in each of the axial segments | p. 279 |
Calculating the coolant temperature | p. 280 |
Calculating the reactivity | p. 280 |
Bibliography | p. 281 |
Process controllers and control valve dynamics | p. 282 |
Introduction | p. 282 |
The proportional controller | p. 282 |
The basic operation of the proportional plus integral controller | p. 283 |
The proportional plus integral plus derivative (PID) controller | p. 284 |
Integral desaturation | p. 285 |
The dynamics of control valve travel | p. 289 |
Modelling static friction: the velocity deadband method | p. 290 |
Using nonlinearity blocks: the backlash description of value static friction | p. 291 |
Bibliography | p. 295 |
Linearization | p. 296 |
Introduction | p. 296 |
Principles of linearization | p. 296 |
Example of analytic linearization: the response of liquid flow to valve opening in a pumped liquid system | p. 297 |
Response of flow to value opening when the differential pressure controller is switched out | p. 298 |
Including the effect of the differential pressure controller | p. 301 |
Using the linear block diagram | p. 307 |
Bibliography | p. 307 |
Model validation | p. 308 |
Introduction | p. 308 |
The philosophy of model validation | p. 308 |
The concept of Model Distortion | p. 309 |
Transfer-function-based technique for model distortion | p. 311 |
Time-domain technique for the solution of the model distortion equations | p. 317 |
Applications | p. 322 |
Bibliography | p. 322 |
Appendices | |
Comparative size of energy terms | p. 323 |
Introduction | p. 323 |
Bulk kinetic energy | p. 323 |
The relative size of the potential energy term | p. 323 |
Vessel filled with liquid or gas | p. 324 |
Liquid partially filling a vessel | p. 324 |
Gas partially filling a vessel, contained above a movable surface, e.g. a liquid surface, undergoing a near-adiabatic expansion or compression | p. 325 |
Explicit calculation of compressible flow using approximating functions | p. 328 |
Introduction | p. 328 |
Applying dimensional analysis to compressible flow | p. 328 |
The shape of the dimensionless flow function, f[subscript pipe] | p. 328 |
Developing a long-pipe approximation to the full compressible flow equations | p. 333 |
Calculation of b[subscript 0] | p. 336 |
Using polynomial functions to characterize the b[subscript 0] surface | p. 336 |
Size of errors using approximating functions | p. 337 |
Simplified approximation using a constant value of b[subscript 0] | p. 338 |
Bibliography | p. 340 |
Equations for control valve flow in SI units | p. 341 |
Introduction | p. 341 |
Liquid flow through the valve | p. 341 |
Gas flow at small pressure drops in US units | p. 341 |
Gas flow at very large pressure drops | p. 342 |
Gas flow at intermediate pressure drops: the Fisher Universal Gas Sizing Equation (FUGSE) | p. 342 |
Converting the Fisher Universal Gas Sizing Equation to SI units | p. 343 |
Summary of conversions between SI and US value coefficients | p. 343 |
Comparison of Fisher Universal Gas Sizing Equation, FUGSE, with the nozzle-based model for control valve gas flow | p. 344 |
Introduction | p. 344 |
Comparison of the Fisher Universal Gas Sizing Equation, FUGSE, with direct data | p. 344 |
Comparison of the FUGSE with the nozzle-based model for control valve gas flow | p. 345 |
Measurement of the internal energy of reaction and the enthalpy of reaction using calorimeters | p. 348 |
Introduction | p. 348 |
Measuring the internal energy of reaction using the bomb calorimeter | p. 348 |
Measuring the enthalpy of reaction using an open-system calorimeter | p. 349 |
Comparison of efficiency formulae with experimental data for convergent-only and convergent-divergent nozzles | p. 351 |
Experimental results | p. 351 |
Theory versus experiment for the convergent-only nozzle | p. 353 |
Divergence ratio for the convergent-divergent nozzles | p. 355 |
Interpreting the experimental results for convergent-divergent nozzles | p. 357 |
Comparing calculated efficiency curves with measured efficiency curves | p. 359 |
Conclusions | p. 362 |
Reference | p. 362 |
Approximations used in modelling turbine reaction stages in off-design conditions | p. 363 |
Axial velocity over the fixed blades at off-design conditions for a 50% reaction stage | p. 363 |
Degree of reaction at off-design conditions for a 50% reaction stage | p. 365 |
Fuel pin average temperature and effective heat transfer coefficient | p. 369 |
Introduction | p. 369 |
Applying Fourier's law of heat conduction to the fuel | p. 369 |
Heat transfer across the gas gap | p. 371 |
Heat transfer through the cladding | p. 371 |
Heat transfer from the cladding to the coolant | p. 371 |
The overall heat transfer coefficient | p. 371 |
Example of calculating average fuel temperatures in a PWR | p. 372 |
Bibliography | p. 373 |
Conditions for emergence from saturation for P + I controllers with integral desaturation | p. 374 |
Introduction | p. 374 |
Type 1 integral desaturation | p. 374 |
Type 2 integral desaturation | p. 375 |
Type 3 integral desaturation | p. 377 |
Index | p. 379 |
Table of Contents provided by Syndetics. All Rights Reserved. |
ISBN: 9780750641616
ISBN-10: 0750641614
Audience:
Professional
Format:
Hardcover
Language:
English
Number Of Pages: 390
Published: 11th August 1999
Publisher: Elsevier Science & Technology
Country of Publication: GB
Dimensions (cm): 25.2 x 19.5
x 2.39
Weight (kg): 0.75