Boiler Inspection Technics Presented by ENG.Hatem Jafoura 28 October 2021 Preparation for Inspection • Review of Boiler History & Inspection Data • Inspection reports ,failure reports, operation defects, instrumentation faults, chemical dosing system SAFETY FIRST RESPECT OF LOTO PROCEDURES, TEMPERATURE ,GAS COVERALL, HELMET, SAFETY SHOES , GLOVES, LAMP TORCH, MASK INSURE GOOD LIGHTING PHOTO APPARAT, MARKER Simplified Boiler Flow Diagram Inspection Scope The following areas should be included in the Boiler Visual Inspection scope • Gas Path • Supporting Structures • Basement • Steam/Water Side • Exterior • Drums & Tanks Inspection scope • Inspection is part of routine maintenance for boilers. Visual inspections are performed at regular intervals in accordance with the requirements of regulatory bodies and insurers. • Damage mechanisms vary in severity based on materials selected by the Boiler manufacturer, local operating stresses and the interaction between vibration and corrosion mechanisms • Deformation • Discoloration • Crack Boiler damage mechnism • High temperature progressive deformation of a material at constant stress is called creep. When a metal or alloy is under a constant load or stress, it may undergo progressive plastic deformation. • Three kinds of mechanisms are operative in creep: dislocation related, diffusional, grain boundary sliding Creep mechnism Visual Inspection • The predominant technique for inspecting Boilers is visual. Visual inspection is performed at nearly every opportunity. • Generally, a visual exam during a walkdown of the interior to view accessible components within the gas path as well as the adjoining accessible compartments. • Boiler compartments contain interconnecting piping such as jumpers, risers, drains and vents. Visual Inspection • The walkdown should also include drum internals and the Boiler casing with supporting structures. The external power piping on the unit and piping supports might be added given sufficient time. Deaerator tanks and condensers are also subject to visual inspection and periodic non-destructive inspection as required Inspection tools • Boiler component damage may include: failed pressure parts (even if the specific tube/header is relatively inaccessible – leaking water can usually be spotted), leaking or failed drains, damage to structural components and supports such as duct burner runners, gas baffles, casing liner plates, insulation, penetration seals and expansion joints. In addition, sophisticated visual instruments provide enhanced inspection of interior surfaces via borescopes, videoscopes and a variety of special purpose optical instruments such as laser profilometers. These tools provide effective means to identify corrosion, cracking and related damage to tubes, headers, flow nozzles, riser piping to drums and feeders Inspection areas Furnace walls inspection Flame impingement & tube thinning Tube hangers' inspection Soot blower Steam drum Critical point in welded joint Remote Visual Inspection (RVI), or Borescope • Flexible video inspection probes employ high-resolution camera at the probe tip to capture detailed colored inspection footage. Interchangeable lenses bring subjects both near and far into sharp focus. Variableintensity fiber optic illumination floods hidden targets with cool, white light Borescope, tube deposit Weld inspection Weld symboles • In-situ metallography, replica testing is a procedure that consists in reproducing the microstructure of a metal's surface. It enables experts to determine creep damage and to estimate the remaining service lifetime of a piece of equipment Replica testing Granularity Analysis • Granularity Analysis" solution of Stream Image Analysis Software allows inspectors to measure the "grain size number" Before &After Water wall cleaning • The ash contains varying amounts of vanadium, alkalines, sulfur, and other elements. • Insoluble residue along with a bonding binder which adheres to the water wall, superheater and reheater surfaces. • This densely bonded mass may not be completely removed by normal cleaning devices such as soot blowers. • High pressure washing may be used for washing Other inspection activities • Tube sampling (when required) • Tube internals chemical cleaning (if necessary) • Hydrostatic test after major repair of replacement. • Boiler tubes replacement • Boiler tubes washing/ blasting • Boiler tubes spry metallic coating Non destructive testing Inspection records Ultrasonic testing Replica testing Records Regulation requirements • • • • Inspection report: Date of inspection Raison of shutdown Observations: reading, thickness, NDT • Action taken • Methods used • Recommendation for the next shutdown • ASME Boiler B31.1 Power Piping Code • Track Plant History Inspection report sample See attached Questions & Answers End of the presentation Thank You