Application Guides

Gasifier Shutdown Corrosion Inspection Workflow

A gasifier shutdown creates a limited opportunity to preserve as-found evidence before cleaning changes the surface. This workflow organizes inspection by equipment zone, distinguishes deposits from possible corrosion or erosion, and records what requires closer testing or engineering review. It does not assert that a DAYU-X product was used on the inspected equipment.

Define the shutdown inspection boundary

Confirm isolation, safe access and the exact internal surfaces covered by the inspection plan. Divide the gasifier into traceable elevations, orientations and transition zones so findings can be returned to after cleaning or repair.

Identify waterwall, membrane, weld and attachment zones.
Mark transitions, openings and known repair areas.
Record surfaces that cannot be accessed safely.
Assign a location reference to every image and observation.

Preserve evidence before cleaning

Capture gasifier as-found patterns before deposits are disturbed. Record deposit colour, distribution, apparent thickness variation, flow direction, detached material and relationships to equipment geometry as visual observations, not a chemical identification.

Separate deposits, corrosion, erosion, and old repairs

Use morphology and location to establish investigation categories rather than declaring a mechanism from one photograph. Deposits can cover wall loss; cleaning can create marks; and an earlier repair can interrupt an otherwise repeated pattern.

Deposit and flow-pattern observations

Map accumulations, clean tracks, directional marks and shielded regions in relation to gas or particle movement. Note where sampling or operating information is needed before a mechanism can be evaluated.

Possible corrosion, erosion, and combined damage

Record pitting, scale disruption, directional loss, polished areas and local attack as observations. Where mechanisms may interact, keep the categories open until measurements and relevant technical review are complete.

Map waterwall and transition-zone findings

Pay particular attention to weld transitions, membrane connections, openings, attachments, repaired areas and changes in gas-path exposure. Compare equivalent zones where possible to distinguish a repeated operating pattern from an isolated defect.

Repeat the inspection after controlled cleaning

Gasifier shutdown inspection should connect the as-found record with a repeat inspection after controlled cleaning at the same location references. Retain both image sets so hidden damage, cleaning effects and remaining deposits are not confused. Keep ambiguous findings open for measurement, sampling or engineering review rather than declaring a mechanism from appearance. Visual records support condition mapping; they do not establish chemistry, corrosion rate, structural capacity, service life or product suitability.

Preserve deposit and damage patterns before cleaning.
Return to the same mapped zones after controlled cleaning.
Compare as-found and cleaned observations without assuming the damage mechanism.
Record measurement, sampling or engineering hold points for unresolved findings.

Create traceable hold points and escalation records

Define which zones can proceed to preparation, which require measurement or sampling, and which remain outside coating work. Cracks, bulging, leakage, structural wall loss or ambiguous widespread damage require the appropriate engineering review.

Limits of shutdown visual inspection

Visual evidence supports location and condition mapping, but it does not determine material chemistry, corrosion rate, remaining structural capacity, future service life or product suitability. Keep those conclusions separate and evidence-led.