The Nalco guide to boiler failure analysis : Nalco Chemical Company

Preface ........................................................................... v 1. Water-Formed and Steam-Formed Deposits ........... 1 Locations ............................................................................. 1 General Description ............................................................. 2 Critical Factors ..................................................................... 6 Identification ......................................................................... 10 Elimination ........................................................................... 19 Cautions ............................................................................... 19 Related Problems ................................................................ 19 2. Long-Term Overheating ............................................ 29 Locations ............................................................................. 29 General Description ............................................................. 30 Critical Factors ..................................................................... 36 Identification ......................................................................... 37 Elimination ........................................................................... 38 Cautions ............................................................................... 38 Related Problems ................................................................ 39 3. Short-Term Overheating ........................................... 47 Locations ............................................................................. 47 General Description ............................................................. 47 Critical Factors ..................................................................... 48 iv Contents This page has been reformatted by Knovel to provide easier navigation. Identification ......................................................................... 48 Elimination ........................................................................... 50 Cautions ............................................................................... 51 Related Problems ................................................................ 52 4. Caustic Corrosion ..................................................... 57 Locations ............................................................................. 57 General Description ............................................................. 57 Critical Factors ..................................................................... 58 Identification ......................................................................... 60 Elimination ........................................................................... 60 Cautions ............................................................................... 63 Related Problems ................................................................ 63 5. Chelant Corrosion ..................................................... 71 Locations ............................................................................. 71 General Description ............................................................. 71 Critical Factors ..................................................................... 73 Identification ......................................................................... 73 Elimination ........................................................................... 74 Cautions ............................................................................... 74 Related Problems ................................................................ 74 6. Low-pH Corrosion during Service ........................... 81 Locations ............................................................................. 81 General Description ............................................................. 81 Critical Factors ..................................................................... 82 Identification ......................................................................... 83 Elimination ........................................................................... 83 Cautions ............................................................................... 84 Related Problems ................................................................ 85 Contents v This page has been reformatted by Knovel to provide easier navigation. 7. Low-pH Corrosion during Acid Cleaning ................ 95 Locations ............................................................................. 95 General Description ............................................................. 95 Critical Factors ..................................................................... 98 Identification ......................................................................... 98 Elimination ........................................................................... 98 Cautions ............................................................................... 99 Related Problems ................................................................ 99 8. Oxygen Corrosion ..................................................... 109 Locations ............................................................................. 109 General Description ............................................................. 109 Critical Factors ..................................................................... 112 Identification ......................................................................... 112 Elimination ........................................................................... 112 Cautions ............................................................................... 113 Sources of Air In-Leakage .................................................... 114 Related Problems ................................................................ 114 Fire-Side Corrosion ....................................................... 121 Introduction .......................................................................... 121 9. Oil-Ash Corrosion ..................................................... 123 Locations ............................................................................. 123 General Description ............................................................. 123 Critical Factors ..................................................................... 124 Identification ......................................................................... 125 Elimination ........................................................................... 126 10. Coal-Ash Corrosion ................................................. 129 Locations ............................................................................. 129 General Description ............................................................. 129 vi Contents This page has been reformatted by Knovel to provide easier navigation. Critical Factors ..................................................................... 130 Identification ......................................................................... 130 Elimination ........................................................................... 132 11. Waterwall - Fire-Side Corrosion ............................. 135 Locations ............................................................................. 135 General Description ............................................................. 135 Critical Factors ..................................................................... 136 Identification ......................................................................... 136 Elimination ........................................................................... 137 12. Cold-End Corrosion during Service ....................... 143 Locations ............................................................................. 143 General Description ............................................................. 143 Critical Factors ..................................................................... 145 Identification ......................................................................... 146 Elimination ........................................................................... 146 Cautions ............................................................................... 146 13. Dew-Point Corrosion during Idle Periods ............. 149 Locations ............................................................................. 149 General Description .............................................................