Norman P. Lieberman

Troubleshooting Vacuum Systems (eBook, PDF)

Steam Turbine Surface Condensers and Refinery Vacuum Towers

• Format: PDF

Produktbeschreibung

Vacuum systems are in wide spread use in the petrochemical plants, petroleum refineries and power generation plants. The existing texts on this subject are theoretical in nature and only deal with how the equipment functions when in good mechanical conditions, from the viewpoint of the equipment vendor. Also, the existing texts fail to consider the interaction of the vacuum system with the process equipment it serves and the variability of the motive steam conditions, change in cooling water temperature condenser fouling and erosion of the ejectors. Here are some of the many questions answered in this groundbreaking volume: * Why does my first stage jet make a surging sound during hot weather? * Why does the vacuum suddenly break? * I've seen moisture condensing on the jet's body! What's causing that? * Why do I have to steam-out the drain legs from our condensers? * Superheated steam is making our vacuum worse. Is this normal? * How can I locate and measure air leaks? * Reducing the steam pressure to my jets improves vacuum. But why? * I can't pull the pre-condenser bundle. The shell side is fouling. What should I do? * We're not getting our normal horsepower from our steam turbine. Could this be a jet problem? * Raising the seal drum level improves vacuum! Is there an explanation for this? * Our turbine exhaust steam pressure to our surface condenser has doubled in the last two years. What should we do? * Restricting cooling water flow from our elevated condensers improves vacuum! Is this possible? * What's a converging-diverging ejector all about? * What's the difference between a barometric condenser and a surface condenser? Which is better?

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Produktdetails

• Verlag: John Wiley & Sons
• Seitenzahl: 280
• Erscheinungstermin: 19. Dezember 2012
• Englisch
• ISBN-13: 9781118571200
• Artikelnr.: 37347118

Autorenporträt

Norm Lieberman is one of the most well-known and respected process engineers in history. With over 47 years of experience and eight often-quoted and often-used books to his credit, he has left and continues to leave a lasting impression on the energy industry. His contribution to the industry is considerable, and troubleshooting vacuum systems is the single biggest part of his business. With a writing style that is unique to technical books, he brings a no-nonsense and practical approach to his subjects.

Inhaltsangabe

Preface xiii Introduction xv Definition of Terms xix Other Books by Author
xxiii 1 How Jets Work 1 1.1 The Converging-Diverging Ejector 1 1.2
Interaction of Steam Nozzle with Converging-Diverging Diffuser 5 1.3
Compression Ratio 6 1.4 Converging-Diverging Ejector 7 1.5 Velocity Boost 9
1.6 Surging 10 1.7 Critical Discharge Pressure 11 1.8 Observing the
Conversion of Heat to Velocity 12 1.9 Jet Discharge Pressure 13 1.10
Reducing Primary-Jet Discharge Pressure 14 1.11 Bypassing First Stage
Ejectors 15 2 Making Field Measurements 17 2.1 Getting Started 17 2.2 How
to Unscrew Steel Plugs 23 2.3 Effect of Barometric Pressure on Indicated
Vacuum 24 2.4 Use of Piccolo 25 2.5 Measuring Deep Vacuums using an Hg
Manometer 27 2.6 Measurement of a Deep Vacuum without Mercury 28 2.7
Measuring Condensibles in Feed to First Stage Ejector 30 2.8 Identifying
Loss of Sonic Boost by Sound 31 2.9 Identifying Air Leaks 32 2.10 Air Leaks
in Flanges 34 2.11 Vacuum Measurement Units 35 3 Tabulation of Vacuum
System Malfunctions 39 3.1 Tidal Flop in Delaware 40 3.2 Critical Discharge
Pressure 43 3.3 Fouling in Final Condenser 43 3.4 Reduction in Back
Pressure 45 3.5 Loss of LVGO Pan Level 45 3.6 Variations in Cooling Water
Temperature 47 3.7 Multi-Component Malfunctions 50 3.8 Partial Tabulation
of Vacuum System Malfunctions 51 4 Effect of Water Partial Pressure on Jet
Efficiency 55 4.1 Vapor Pressure of Water Limits Vacuum 56 4.2 Reminder
about Water Partial Pressure 59 4.3 Air Leaks in Steam Turbine Surface
Condensers 59 4.4 Variable Cooling Water Temperature 60 4.5 Loss of Sonic
Boost 60 4.6 Relative Jet Efficiency 62 4.7 Definition of "Vacuum Breaking"
63 4.8 Critical Discharge Pressure Exceeded 64 5 Air Leaks 67 5.1 Upper
Explosive Limits 67 5.2 How to Find Air Leaks 68 5.3 Diffuser Air Leaks 69
5.4 Air Leaks on Vacuum Towers 70 5.5 Air Leaks in Heater Transfer Lines 71
5.6 Air Leaks - Turbine Mechanical Seal 72 6 Sources and Disposal of
Hydrocarbon Off-Gas 75 6.1 Evolution of Cracked Gas 75 6.2 Sources of
Cracked Gas 78 6.3 Cracked Gas Evolution from Boot 80 6.4 Air Equivalent 81
6.5 Overloading Vacuum Jets 84 6.6 Excess Cracked Gas Flow 85 6.7 Field
Checking Gas Flow Meter in Vacuum Service 85 6.8 Surging 3rd Stage Jet Bogs
Down Primary Jet 89 6.9 Exchanger Leaks Overloads Jets 90 6.10 Poor Vacuum
Tower Feed Stripping 92 6.11 Level Connection Purges and Pump Mechanical
Seal Gas 94 6.12 Effect of Heater Outlet Temperature 95 6.13 Extracting H2S
from Vacuum Tower Off-Gas Upstream of Ejectors 97 6.14 Disposal of Seal
Drum Off-Gas 99 6.15 Fouling of Waste Gas Burner 100 7 Motive Steam
Conditions 101 7.1 Effect of Wet Steam 102 7.2 Water in Motive Steam 103
7.3 The Tale of Weak Steam 104 7.4 Internal Freezing of Steam Nozzle 105
7.5 High Pressure, Superheated Motive Steam 108 7.6 Effect of Moisture
Content of Saturated Steam on Temperature 108 7.7 Steam Pressure Affects
Vacuum 109 7.8 Effect of Superheated Steam 111 8 Mechanical Defects of
Ejectors 113 8.1 Steam Nozzle Testing 113 8.2 Other Mechanical Defects of
Jets 114 8.3 Fouled Steam Nozzles 117 8.4 Diffuser Erosion 118 8.5 Repair
of Ejector Body 119 8.6 Changing Worn Steam Nozzles 119 8.7 Restoring
Critical Flow 120 9 Condenser Fouling and Cleaning 123 9.1 Fouling
Mechanism in Condensers for Refinery Vacuum Towers 123 9.2 Fouling Due to
Chemical Additives 124 9.3 Minimizing Condenser Fouling in Vacuum Towers
125 9.4 Fouled Pre-condenser 126 9.5 Fixed Tube Sheet Condensers 128 9.6
Cleaning Condensers On-Stream 129 9.7 Optimum Condenser Bundle
Configuration 130 9.8 Chemically Cleaning Condensers 130 9.9 Ball Cleaning
Condenser Tubes 131 9.10 Corrosion Control by Better Desalting 132 10
Pressure Control of Vacuum Towers 135 10.1 Positive Feedback Loop 141 11
Condenser Cooling Water Flow 143 11.1 Cooling Water Flow Configuration 143
11.2 Air Evolving from Cooling Water Reduces Cooling Water Flow 145 11.3
Cooling Water Pressure to Surface Condensers 148 11.4 Tube Leaks 149 12
Condensate Back-Up in Condensers 151 12.1 Undersized Condenser Drain Nozzle
153 12.2 Seal Drum Level Indication 155 12.3 Leaking Gauge Glass on Surface
Condenser Boot 157 12.4 Condensate Pump Cavitation Due to Air Leaks 161
12.5 Condensate Back-Up in Surface Condenser Boot 162 12.6 Experiment with
Condensate Back-Up 165 12.7 Condensate Back-Up 166 13 Seal Leg Drainage 169
13.1 Sludge Accumulation in Seal Drum 169 13.2 Seal Leg Leak Inside Seal
Drum 171 13.3 Seal Leg Flange Leak Outside Seal Drum 174 13.4 Seal Leg
Design 177 13.5 Inadequate Seal Leg Length for Hydrocarbons 180 13.6
Inadequate Seal Leg Capacity 182 13.7 High Back-Pressure from Seal Drum 183
13.8 Detecting Condensate Back-Up in Seal Legs 184 13.9 Condensate Back-Up
Due to Air Leak in Barometric Drain Line 186 13.10 Seal Drum Design 188
13.11 Seal Drum Fills with Corrosive Deposits 189 13.12 Seal Drum Design
Tips 193 13.13 An Unfortunate Incident 194 14 Other Types of Vacuum
Equipment 197 14.1 Hogging Jets 197 14.2 Use of Hogging Jet on Surface
Condenser 198 14.3 Liquid Seal Ring Compressors 200 14.4 Gas Ejectors 202
14.5 Liquid Ejectors 203 14.6 Ejector Compression Efficiency 204 15 Air
Baffle and Impingement Plate in Surface Condensers 205 15.1 Mechanical
Configuration of Seal Strips 206 15.2 Corroded Brass Seal Strips 208 15.3
Air or Vapor Baffle Leak 208 15.4 Identifying Defective Seal Strips 209
15.5 Air Baffle Clearance 211 15.6 Fouling Mechanism in Vacuum Tower
Surface Condensers 212 15.7 Surface Condenser Impingement Plate 212 15.8
Oversized Impingement Plate 214 15.9 Impingement Plates as Vapor
Distributors 215 16 Optimizing Vacuum Tower Operation 217 16.1 Steam to
Heater Passes 218 16.2 LVGO Pan Level Loss Causes a Loss in Vacuum 220 16.3
Carry-Over of LVGO Pumparound Spray 226 16.4 Optimizing Vacuum Tower Top
Temperature 227 16.5 Plugged Vacuum Tower Top Demister 229 16.6 Bypassing
Primary Ejector 232 17 Frequently Asked Questions 233 17.1 Vacuum Systems
233 The Norm Lieberman DVD/Video Library 243 Index 247