Boiler operator's handbook

Chapter 1 - OPERATING WISELY .............................................. 1 Why wisely? .......................................................................... 1 Prioritizing ............................................................................. 1 Safety ....................................................................................... 5 Measurements ....................................................................... 7 Flow ...................................................................................... 13 What happens naturally ................................................... 14 Water, steam and energy .................................................. 15 Combustion.......................................................................... 18 The central boiler plant ..................................................... 25 Electricity .............................................................................. 26 Documentation .................................................................... 31 Standard Operating Procedures ...................................... 33 Disaster Plans ...................................................................... 36 Logs ....................................................................................... 37 Chapter 2 - OPERATIONS .......................................................... 45 Operating Modes ................................................................ 45 Valve manipulation ............................................................ 45 New startup ......................................................................... 49 Dead plant startup ............................................................. 62 Normal boiler startup ........................................................ 63 Emergency boiler startup .................................................. 65 Normal operation ............................................................... 67 Idle equipment .................................................................... 69 Superheating ........................................................................ 72 Switching fuels .................................................................... 73 Standby operation .............................................................. 75 Rotating (alternating) boilers ........................................... 76 Bottom blowoff ................................................................... 77 Annual inspection .............................................................. 78 Operating during maintenance and repairs .................. 80 Pressure testing ................................................................... 81 Lay-up................................................................................... 83 Tune-ups ............................................................................... 84 Auxiliary turbines .............................................................. 88 Chapter 3 - WHAT THE WISE OPERATOR KNOWS .......... 93 Know your load ................................................................. 93 Know your plant ................................................................ 97 Matching equipment to the load .................................... 98 Efficiency ............................................................................ 100 Performance monitoring ................................................. 105 Modernizing and upgrading .......................................... 106 Chapter 4 - SPECIAL SYSTEMS .............................................. 109 Vacuum systems ............................................................... 109 Hydronic heating .............................................................. 110 High temperature hot water (HTHW) ......................... 114 Organic fluid heaters and vaporizers .......................... 116 Service water heating ...................................................... 118 Waste heat service ............................................................ 123 Chapter 5 - MAINTENANCE .................................................. 125 Maintenance....................................................................... 125 Cleaning ............................................................................. 126 Instructions and specifications ....................................... 127 Lock-out, tag-out .............................................................. 128 Lubrication ......................................................................... 129 Insulation ........................................................................... 132 Refractory ........................................................................... 134 Packing ............................................................................... 136 Controls and instrumentation ........................................ 138 Lighting and electrical equipment ................................ 140 Miscellaneous .................................................................... 143 Replacements ..................................................................... 144 Maintaining efficiency ..................................................... 148 Records ............................................................................... 149 Chapter 6 - CONSUMABLES ................................................... 151 Fuels .................................................................................... 151 Fuel gases ........................................................................... 152 Oils ...................................................................................... 154 Coal ..................................................................................... 159 Other solid fuels ............................................................... 160 Water ................................................................................... 162 Treatment chemicals ......................................................... 164 Miscellaneous .................................................................... 165 Chapter 7 - WATER TREATMENT ......................................... 167 Water treatment ................................................................ 167 Water testing ...................................................................... 168 Pretreatment ...................................................................... 172 Feedwater tanks and deaerators ................................... 175 Blowdown .......................................................................... 179 Chemical treatment .......................................................... 180 Preventing corrosion ........................................................ 182 Preventing scale formation ............................................. 184 Chapter 8 - STRENGTH OF MATERIALS ............................ 187 Strength of materials ....................................................... 187 Stress ................................................................................... 187 Cylinders under internal pressure ................................ 189 Cylinders under external pressure................................ 191 Piping Flexibility .............................................................. 192 Chapter 9 - PLANTS AND EQUIPMENT ............................. 195 Types of Boiler Plants ...................................................... 195 Boilers ................................................................................. 196 Heat transfer in boilers ................................................... 197 Circulation .......................................................................... 199 Construction ...................................................................... 202 Boiler, cast iron and tubeless ......................................... 203 Table of Contents vi Firetube boilers ................................................................. 203 Watertube boilers .............................................................. 208 Trim ..................................................................................... 219 Heat traps .......................................................................... 231 Burners ............................................................................... 234 Pumps ................................................................................. 249 Fans and blowers ............................................................. 268 Cogeneration ..................................................................... 280 Chapter 10 - CONTROLS The basics ........................................................................... 289 Self contained controls .................................................... 305 Linearity ............................................................................. 307 Steam pressure maintenance .......................................... 308 Fluid temperature maintenance ..................................... 312 Fluid level maintenance .................................................. 314 Burner management......................................................... 318 Firing rate control ............................................................ 321 Low fire start ..................................................................... 322 High-Low ........................................................................... 322 Burner cutout .................................................................... 323 Jackshaft control ............................................................... 323 Establishing linearity ....................................................... 326 Startup control .................................................................. 327 Parallel positioning .......................................................... 328 Inferential metering .......................................................... 330 Steam flow / air flow ..................................................... 330 Full metering cross limited ............................................ 331 Dual fuel firing ................................................................. 333 Choice fuel firing .............................................................. 334 Oxygen trim ...................................................................... 334 Combustibles trim ............................................................ 336 Draft control ...................................................................... 336 Feedwater pressure control ............................................ 338 Instrumentation ................................................................. 340 Chapter 11 - WHY THEY FAIL A little bit of history ........................................................ 347 Low water .......................................................................... 347 Thermal Shock .................................................................. 349 Corrosion and wear ......................................................... 350 Operator error and poor maintenance ......................... 350 APPENDICES Properties of water and steam ...................................... 353 Water pressure per foot head ........................................ 357 Nominal capacities of pipe ............................................. 358 Properties of pipe ............................................................. 360 Secondary ratings of joints, flanges, valves, and fittings ................................. 368 Pressure ratings for various pipe materials ................ 371 Square root curve ............................................................. 372 Square root graph paper ................................................. 373 Viscosity conversions ....................................................... 374 Thermal expansion of materials .................................... 376 Value conversions ............................................................. 377 Combustion calculation sheets ...................................... 378 Excess air/O2 curve ......................................................... 384 Properties of Dowtherm A ............................................. 385 Properties of Dowtherm J ............................................... 386 Chemical Tank Mixing Table ......................................... 387 Suggested mnemonic abbreviations for device identification .............................................. 389 Specific heats of common substances .......................... 391 Design temperatures for selected cities ....................... 392 Code Symbol Stamps....................................................... 395 Bibliography ................................................................................. 396 Index ............................................................................................. 397