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