Applied Technology and Instrumentation for Process Control

by de Sa; Douglas O

• ISBN13: 9781591690214
• ISBN10: 1591690218
• Format: Hardcover
• Copyright: 2004-01-28
• Publisher: CRC Press

Summary

Applied Technology and Instrumentation for Process Controlpresents the complex technologies of different manufacturing processes and the control instrumentation used. The large variety of processes prohibits covering more than a few. Carefully selected and diverse, but representative, examples show how fundamentally basic simpler elements or techniques can be coordinated and expanded into more control systems. This book is suitable for all levels of practitioners and engineers in related industries or applications.

Author Biography

Douglas O.J. deSa has been involved in the field of process instrumentation and control since he emigrated to the U.K. in 1958. In 1973 he joined the Foxboro Company, where he initiated, developed and commissioned several advanced control systems. He has worked in Europe, Canada, and the United States, and lectured at several colleges and universities in the U.K. He has been retired since 1997

Table of Contents

PREFACE	xvii
INTRODUCTION	xix
NOTATION USED IN THIS BOOK	xxi
INSTRUMENTATION SYMBOLS USED IN THIS BOOK	xxiii
TAG NUMBER SYSTEM USED IN THIS BOOK	xxv
CHAPTER 1 APPLICABILITY OF MISCELLANEOUS CONTROL STRATEGIES-INDUSTRYWIDE	1	(34)
PROPORTIONING OR RATIO CONTROL	1	(2)
Other Industries Using Similar Ratioing Techniques	2	(1)
SOLID MATERIAL CONVEYING SYSTEMS	3	(2)
Other Industries Using Conveyor Techniques	5	(1)
HEAT GENERATION	5	(9)
Furnace Control	5	(1)
Simplified Combustion Theory	6	(2)
Special (Analytical) Instruments	8	(1)
Other Industries Using Similar Space-Heating Techniques	9	(1)
Multiple Fuel Systems	10	(1)
Considerations for a Rapidly Changing Demand	11	(3)
PRODUCT QUALITY CONTROL	14	(4)
pH Measurement and Control	14	(1)
Mixing-Vessel Level Control	15	(1)
Industries That Use pH as a Measurement of Quality	16	(1)
Conductivity Measurement and Control	16	(2)
Industries That Use Conductivity as a Measurement of Quality	18	(1)
OTHER INDUSTRIES THAT REQUIRE CONTROL OF PARAMETERS ALREADY DISCUSSED	18	(2)
Glass Furnaces	18	(1)
Basic Oxygen Furnaces-Steel Making	19	(1)
SOME CONSIDERATIONS ON INSTRUMENTATION AND CONTROL METHODS	20	(9)
Instrumentation	20	(4)
Flow	20	(1)
Volumetric Flow	20	(1)
Mass Flow	20	(1)
Compensating Flow Measurement	21	(1)
Pressure	21	(1)
Level	21	(1)
Temperature	22	(2)
Mechanical Methods	22	(1)
Thermoelectric Devices	23	(1)
Element Protection	23	(1)
Analytical	24	(1)
Control	24	(12)
Mass Measurement with Differential-Creating Primary Devices	24	(1)
Corrected Volumetric Flow with Direct Flow-Measuring Devices	25	(1)
Flow Integration	25	(1)
Signal Selection	26	(1)
Integral Saturation or Reset Windup	26	(1)
Signal Characterizers	27	(1)
Ramp Generators	28	(1)
Controller Output Bias Adjustment	28	(1)
SUMMARY	29	(6)
CHAPTER 2 DIGESTERS-PAPER PULP	35	(48)
CONTROL OF CONTINUOUS PULP DIGESTERS IN PAPER MAKING	35	(1)
PRE-PULPING PROCESSES	36	(3)
Processing the Waste From Logging Operations	36	(1)
Offcut Processing	36	(1)
Solvent Extraction	36	(1)
Preparing the Logs of Wood for Pulping	37	(2)
The Abrasive Method	38	(1)
The Hydraulic Method	39	(1)
THE PULPING PROCESS	39	(6)
Operating Principles	39	(1)
Mechanical Pulping	39	(3)
Chemical Pulping	42	(1)
Alkaline Pulping	42	(1)
Sulfite Pulping	43	(1)
The Kraft Process	44	(1)
Semichemical and Chemimechanical Processes	44	(1)
A Simplified Explanation of the Mechanisms in the Fiber/Chemical Reactions Involved	45	(1)
A TYPICAL REAL PULPING PROCESS	45	(20)
Raw Chip Handling and Pre-Processing	46	(19)
Conveyor Belt or Chain Control	47	(12)
Motor and Conveyor Belt Controls	51	(1)
Motor Control-with Relay Ladder Logic	51	(1)
Enhancement to the Basic Motor Control Circuit-Motor Start/ Stop Feedback	52	(1)
Motor Start/Stop Feedback Circuit with Addition of Conveyor Belt Speed	52	(1)
Motor Control-with Binary Logic	52	(1)
Circuit Functional Description-Last Belt in the Series	53	(1)
Automatic Operation	53	(1)
Automatic Operation-Manual Stop	55	(1)
Manual Operation-Local Start/Stop	55	(1)
Manual Operation-Remote Start/Stop	56	(1)
First and Intermediate Conveyor Belt Control-Relay Ladder Circuit	57	(1)
Circuit Functional Description-First and Intermediate Belt in the Series with Binary Logic	57	(1)
Connecting the Control Circuit to the Drive Motor	58	(1)
The Full Electrical Contactor Circuit	59	(1)
Conveyor Belt Configuration and Material Weighing	59	(1)
Control of the Chip Silo	60	(1)
Control of the Chip Washer	61	(1)
Control of the Chip Hopper	62	(1)
The Low-Pressure Feeder	63	(1)
Control of the Steaming Vessel	63	(1)
Control of the Chip Chute and Level Tank	63	(1)
The Chip Chute	63	(1)
The Level Tank	64	(1)
The High Pressure Feeder	64	(1)
DIGESTER CONTROL	65	(13)
The Top Separator	65	(3)
The Control of the Digester	68	(4)
Chip/Liquor Level Control	69	(1)
Digester Temperature Control	70	(1)
Digester Pressure Control	70	(1)
Digester Liquor	70	(29)
Liquor Heating	71	(1)
Digester Bottom Scraper	72	(1)
Primary Pulp Refining	73	(2)
Rotary Vacuum Washer	75	(3)
SUMMARY	78	(5)
CHAPTER 3 PAPER MACHINE	83	(64)
THE PAPER MACHINE	83	(1)
THE WET END	83	(1)
THE FOURDRINIER	84	(1)
THE MIXING CHEST	85	(3)
Stock-Proportioning Ratio Control	85	(1)
Stock-Proportioning Pacing Ratio Control	86	(2)
PULPERS	88	(1)
The Stand-Alone Pulper	88	(1)
THE PULPER LOCATED UNDER THE FOURDRINIER MACHINE	89	(5)
The Control of Pulp Consistency-Normal Operation	90	(1)
The Control of Pulp Consistency-Abnormal Operation	91	(1)
The Control of Pulp Consistency-Under Dry End	92	(1)
Paper-Break Conditions
The Control of Pulp Consistency-Under Full	93	(1)
Paper-Break Conditions
The Control of Pulp Consistency-Stand-Alone Pulper	94	(1)
PULP ADDITIVES	94	(3)
Sizing	95	(1)
Rosin Size	95	(1)
Latex	96	(1)
Starch	96	(1)
Alum	96	(1)
Fillers	97	(1)
SOME OF THE FILLERS USED	97	(1)
Clay	97	(1)
Calcium Sulfate-CaSO4	97	(1)
Calcium Carbonate-CaCO3	98	(1)
PULP PREPARATION EQUIPMENT	98	(6)
The Hollander	98	(1)
The Jordan	99	(4)
The Time-Proportioning Controller	100	(2)
The Refiner Control System	102	(1)
Disk Refiners	103	(1)
CONTROL OF HIGH-CONSISTENCY STUFF	104	(2)
Single Dilution of the Stock	105	(1)
Double Dilution of the Stock	105	(1)
Double Dilution of the Stock-System Operation	105	(1)
THE HEADBOX	106	(6)
Open Type	107	(1)
Control Techniques Used to Ensure an Even Distribution of the	107	(1)
Stock
The Headbox Slice	108	(4)
A Mechanical Method	108	(1)
Instrumentation-Assisted Stock-Level Control of the Headbox	109	(3)
Rush/Drag Control 111
Stock pH Control	112	(1)
WATER DRAINAGE FROM THE STOCK ON THE WIRE	112	(4)
Suction Box Vacuum Control	113	(2)
The Wire Pit	115	(1)
THE DRY END	116	(2)
STEAM DISTRIBUTION TO THE DRIER ROLLS	118	(1)
THE CONTROL SYSTEM FOR THE DRIER ROLL	118	(5)
The Auto-Selector Control System	120	(2)
The Control System for the Drier Rolls-Continued	122	(1)
THE YANKEE MACHINE	123	(7)
Heat Transfer and Drier Performance	124	(1)
Instrumentation and Control for the Yankee Drier	125	(3)
The Thermo-Compressor	128	(2)
MACHINE ROOM VENTILATION	130	(3)
Instrumentation and Control System Operation	131	(1)
Ventilation System for a Yankee Drier	132	(1)
THE VAT OR CYLINDER PAPER MACHINE	133	(3)
SUMMARY	136	(11)
CHAPTER 4 EVAPORATORS	147	(40)
PROCESS EVAPORATORS AND SOME TECHNIQUES TO CONTROL PRODUCTION	147	(16)
Basic Definition of Evaporation	147	(6)
The Principles Involved in the Evaporation Process	147	(1)
Basic Definition of Vaporization	148	(1)
Graphical Concepts of the Evaporation Process	148	(3)
The Results When Applied to Multiple-Effect Evaporator Systems	151	(2)
Some Types of Evaporators Used	153	(5)
The Single-Effect Evaporator-The Short Tube Vertical Type	153	(2)
The Vacuum Pan-As Used in the Sugar Industry (Modified Short Tube Type)	155	(1)
Forced Circulation Evaporator	156	(1)
Long Tube Vertical Evaporator	157	(1)
Long Tube Vertical Black Liquor Evaporator-As Used in the Paper Industry	158	(1)
The Falling Film Evaporator	158	(1)
The Steam Condenser	158	(5)
Principle of Operation of the Steam Condenser	160	(3)
CONTROL OF A MULTIPLE-EFFECT EVAPORATOR PRODUCING A MILK CONCENTRATE	163	(11)
Raw Milk Receipt	163	(1)
Process Equipment	164	(1)
Construction Requirements	164	(1)
Cleaning Requirements	165	(1)
Raw Milk Handling	165	(6)
Pasteurization and First-Stage Evaporation	166	(2)
The Heat Demand	168	(3)
The Milk Concentrating Process	171	(1)
Converting the Milk Concentrate to Powdered Milk	171	(3)
THE MULTIPLE-EFFECT BLACK LIQUOR EVAPORATOR-FOR THE PAPER INDUSTRY	174	(7)
The Boiling Point Rise Sensor/Transmitter	174	(3)
Controlling the Multiple-Effect Black Liquor Evaporator Train	177	(1)
The Recovery Boiler for the Paper Industry-Functionality and Control Instrumentation	178	(1)
The Reduction Zone	178	(2)
The Water/Steam Circuit	180	(1)
The Fuel/Air Control Circuit	181	(1)
THE MULTIPLE-EFFECT EVAPORATOR-FOR THE CANE SUGAR INDUSTRY	181	(2)
System Operation	183	(1)
SUMMARY	183	(4)
CHAPTER 5 PRODUCT DISTILLATION	187	(72)
THE BASICS OF THE DISTILLATION PROCESS	187	(4)
Laboratory Equipment	188	(1)
Industrial Equipment	188	(3)
THE CONVERSION PROCESS	191	(2)
THE PRACTICAL DISTILLATION COLUMN	193	(3)
Liquid/Liquid Solutions	194	(2)
OPERATING A COLUMN IN TOTAL REFLUX MODE	196	(2)
DESIGN OF A DISTILLATION COLUMN	198	(6)
Methods of Calculation	198	(2)
Typical Arrangements of Distillation Columns	200	(1)
The Flash Drum	200	(1)
The Absorption and Rectification Columns	201	(1)
Stripping Columns with and without Reboiler	202	(1)
The Azeotropic Distillation Column	202	(2)
Extractive Distillation Column	204	(1)
DISTILLATION COLUMN CONTROL SYSTEMS	204	(22)
Process Heaters-Control of the Inflow of Energy	205	(1)
The Dowtherm Heating System	205	(2)
Combustion Control of a Direct-Fired Process Heater	207	(1)
Indirect Heaters	207	(4)
Steam-Heated Reboilers	209	(1)
Reboiler Control	210	(1)
Column Feed Preheat	211	(1)
Column Differential Pressure	212	(1)
Condensers-Control of the Outflow of Energy	212	(5)
The Air-Cooled Condenser	212	(5)
The Cooling Fan	214	(1)
Determining Gas Velocity from Velocity Pressure	214	(1)
Velocity of Gases Other Than Air	214	(1)
Determining the Horsepower of the Fan	215	(1)
Fundamental Fan Rules	215	(1)
Measurement of Sound/Noise Intensity	216	(1)
Electric Motor Speed Control	217	(7)
The Direct Current (dc) Machine	217	(2)
The Alternating Current Machine	219	(1)
The Induction Motor	219	(1)
Torque/Rotor Power Factor Relationship	220	(1)
Starting Torque	221	(1)
The Effect of Supply Voltage Variation	222	(1)
Rotor Slip	223	(1)
Speed Control of an Induction Motor	223	(1)
By Rotor Resistance Change	223	(1)
By Pole Changing	223	(1)
Infinitely Variable Speed Control	223	(1)
The Recirculating Dry Air-Cooled Condenser	224	(2)
EXAMPLE (a)	226	(1)
EXAMPLE (b)	226	(1)
EXAMPLE (c)	226	(15)
The Evaporative Condenser	226	(1)
Low-Pressure Columns	227	(1)
Floating Pressure Control of a Column	228	(2)
Implementing a Practical Floating Pressure Controller	228	(2)
Vapor-Pressure Control System for Two-Phase Overhead Products	230	(1)
Control of Internal Reflux in a Column	230	(2)
Basic Controls for a Distillation Column	232	(1)
Other Methods to Control a Distillation Column	233	(1)
Control System for Material (Mass) Balance	234	(1)
Controls Applied When Bottoms Product Is Less Than Distillate	235	(1)
Controls Applied When Distillate Flow Regulates Bottoms	236	(2)
Product Quality
Starting Up and Shutting Down a Distillation Column	238	(21)
Conditions for Normal Running	241	(1)
SUMMARY	241	(18)
CHAPTER 6 PRODUCT BLENDING	259	(40)
IN-LINE PRODUCT BLENDING	259	(17)
Basic Blend-Loop Requirements	260	(1)
The Blending System in a Nonhazardous Environment	260	(1)
The Blending System in a Hazardous Environment	261	(1)
General Overview of a Microprocessor Based Blending System	261	(5)
Configuring a Basic Blend Loop	262	(1)
Functional Detail of the Blender-Single Master	263	(1)
Scaling	263	(2)
Functional Detail of the Blender-Multimaster	265	(1)
Functional Detail of the Multimaster Blender with Supervisory Computer	266	(1)
The Vital Blending Software Blocks	266	(10)
Master 0 Display	266	(4)
Master 0 Operation	268	(2)
Local Master	270	(3)
Local Master Operation	271	(2)
The Blend Loop	273	(3)
Blend Loop Operation	273	(3)
Design and Implementation of a (Specific) Blending System	276	(14)
System Application-Objectives and Overview, Brief System Specification-Physical Requirements	276	(14)
Product Requirements	277	(1)
Operational Requirements	277	(2)
System Overview	277	(1)
Additional Equipment	277	(2)
System Inputs and Outputs	279	(1)
Component Pump Selection	280	(2)
Design Criteria for Pump Selection	282	(1)
Pump Selection Circuit Operation	282	(2)
No Pump Selection Made	282	(1)
Pump Selection and Pump Start from the Control Console (Remote Facility)	282	(1)
Automatic Start of Standby Pump #2	283	(1)
Local Start/Stop Facility	283	(1)
Component Storage Tank Level	284	(1)
Tank Low-Level Alarm	284	(1)
Tank High-Level Alarm	284	(1)
Neither Component Pump Selected	285	(1)
One Component Pump Selected	285	(1)
The Microprocessor Blending Control Unit	285	(5)
Allocation of Input and Output Interfaces	288	(1)
Blender Control System Hierarchy	288	(1)
The RS232-C Serial Communications Link	288	(2)
SOFTWARE DESIGN REQUIREMENTS	290	(8)
Communication Between the Blending Controller and the Personal Computer	290	(9)
The On-Line Mode	290	(4)
Product Delivery	292	(1)
On-Line Manufactured Product Documentation	292	(2)
The Off-Line Mode	294	(22)
Uploading and Downloading the Blending Controller Database	294	(1)
Database Modification	294	(1)
Hard Copies of the Database, Configuration, and Products	294	(1)
Database Configuration	295	(1)
Recipe Handling	295	(1)
Implementing Changes	296	(2)
SUMMARY	298	(1)
CHAPTER 7 THE BREWING INDUSTRY	299	(42)
THE RAW MATERIALS	299	(4)
Barley (and the Malting Process)	299	(1)
Water	300	(1)
Wheat	301	(1)
Oats	301	(1)
Millet	301	(1)
Corn	301	(1)
Yeast and Other Ingredients	302	(1)
Yeast	302	(1)
Hops	302	(1)
Additives	302	(1)
THE CHEMISTRY	303	(2)
Disaccharides	303	(1)
Maltose	304	(1)
A BRIEF GENERAL PROCESS OVERVIEW	305	(1)
Beers-Ales and Lagers	305	(1)
THE PRODUCTION OF MALT	305	(5)
Kiln Instrumentation and Control	305	(2)
Fuel/Air Ratio Control (Heat Input)	307	(1)
Position of the Dampers at the Start of the Malt Finishing Operation	308	(1)
Detailed Operation and Terminating the Malting Process	309	(1)
MILLING	310	(1)
THE MASHING OPERATION	311	(8)
Grain Weighing	311	(2)
Cereal Cooking	313	(3)
The Mashing Operation in Practice	316	(4)
Double Mashing	316	(2)
Decoction Mashing	318	(1)
Calculating the Resulting Temperature When Mash and Hot Water Are Mixed	318	(1)
LAUTERING	319	(1)
THE BREW KETTLE	320	(6)
The Kettle Control System and Logic	322	(3)
The Switching Logic	323	(2)
Wort Cooling	325	(1)
FERMENTATION	326	(5)
Specific Gravity Measurement	328	(2)
Carbon Dioxide Storage	330	(1)
FINISHING THE FERMENTED BEER	331	(1)
Secondary Fermentation	331	(1)
CLARIFICATION	332	(1)
PASTEURIZATION	332	(1)
SUMMARY	333	(8)
CHAPTER 8 PROJECT MANAGEMENT AND ADMINISTRATION	341	(21)
THE TECHNOLOGIST VERSUS THE MANAGER (ADMINISTRATOR)	341	(1)
The Manager (Administrator)	342	(1)
The Technologist	342	(1)
THE REQUIREMENTS OF THE ADMINISTRATOR	342	(1)
STARTING OFF A PROJECT	343	(2)
PRE-PROJECT INVOLVEMENT FOR THE PRODUCT MANUFACTURER	345	(2)
The Manufacturing Site	345	(1)
Project Justifications	346	(1)
Process Aspects	346	(1)
Financial and Legal Aspects	346	(1)
Preparation of the Process Plant Specification	346	(1)
Selection of the Process Plant Constructor	347	(1)
CONSIDERATIONS GIVEN BY THE CONSTRUCTION COMPANY	347	(2)
Technical Aspects	347	(1)
Process Engineering Aspects	347	(1)
Commercial Aspects	348	(1)
The Project Bureaucracy	348	(1)
Legal and Financial Aspects	348	(4)
Legal Input	348	(1)
Financial Input	349	(1)
CONSTRUCTOR'S INVITATION TO BID-ISSUED TO SUBCONTRACTORS	349	(2)
The Construction Specification	350	(1)
RESPONSE OF THE INSTRUMENTATION AND CONTROL SYSTEM MANUFACTURERS	351	(3)
The Field Equipment	352	(1)
Installation and Commissioning	352	(1)
The Control System	352	(1)
Engineering Drawings	353	(1)
The Proposal	353	(1)
The Systems Content	353	(1)
The Instrumentation Content	353	(1)
The Commercial Content	354	(1)
OPENING OF THE TENDER DOCUMENTS FROM CONTRACTORS-BY THE END USER	354	(3)
Award of the Contract to the Successful Instrument and System Vendor-by the Contractor	354	(3)
Setting Up the Project Team	355	(1)
Processing the Manufacture of Project Equipment	355	(1)
Equipment Supplied by Other Manufacturers-Third-Party Suppliers	355	(2)
THE PROJECT SCHEDULE AND ADMINISTRATION	357	(5)
The Role of the Project Engineer	359	(2)
The Role of the Technician	361	(1)
System Checkout and Final Acceptance Test	362	(1)
SYSTEM DOCUMENTATION	362	(1)
SYSTEM PACKAGING AND SHIPPING	363	(1)
CLOSE OUT REPORT	363	(1)
SOME TERMS FOUND IN CONTRACTUAL DOCUMENTS	364	(1)
SUMMARY	365	(4)
BIBLIOGRAPHY	369	(2)
INDEX	371