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Hydroprocessing reactor weld examination

2026-06-06 · Hydrocracker & hydrotreater reactors, high-pressure separators & heat exchangers (API 941 / API 579)

Measured outcomeEvery high-pressure reactor nozzle, girth weld, and clad overlay carries a permanent PAUT and API 579 history on the asset record.

Hydroprocessing units (hydrotreaters, hydrocrackers, and catalytic reformers) operate at high hydrogen partial pressures and temperatures where High Temperature Hydrogen Attack (HTHA per API RP 941), wet H2S cracking (HIC/SOHIC), and stainless weld-overlay disbonding require advanced non-destructive examination (PAUT, TOFD, AUBT) and rigorous fitness-for-service tracking.

Current state before intelliSPEC

  • Advanced NDE files disconnected from the vessel: Phased-array ultrasonic (PAUT) and time-of-flight diffraction (TOFD) encoded scan files sat on contractor hard drives, while only a two-page summary PDF entered the refinery's IDMS.
  • Difficult flaw-growth comparisons: When a subsurface laminar indication or weld-toe crack was re-examined at the next turnaround, analysts had to hunt for the previous outage's setup file, transducer wedge details, and sizing table to prove whether the flaw had grown.
  • Manual API 941 operating-envelope audits: Proving that every carbon and C-0.5Mo steel component had been screened against the latest API 941 Nelson curves required manual spreadsheet cross-references.

Configured path

The refinery configured intelliVISION, intelliNDT, intelliINTEGRITY, intelliCREW, and intelliTRACK.

  1. Weld-by-weld reactor and exchanger map: Every longitudinal seam, circumferential girth weld, nozzle-to-shell weld, internal attachment, and gasket groove was indexed in .
  2. Structured PAUT/TOFD and DICONDE archive: stored encoded scan media, setup parameters, calibration blocks (from ), and examiner ASNT/PCN Level II/III credentials (from ) directly on the weld record.
  3. API 581 and API 579 flaw tracking: Subsurface indications were logged with length, through-wall height, and depth below surface in , linking multi-cycle sizing comparisons and engineer-verified fitness-for-service evaluations.

Measured outcome

  • Cycle-to-cycle flaw repeatability: Advanced NDE crews open the exact prior scan parameters, datum points, and indication coordinates before placing the probe on the shell.
  • Complete HTHA and wet H2S governance: Every susceptible circuit and vessel is mapped to its API 571 damage mechanism and API 941 inspection plan.
  • Defensible run-or-repair engineering calls: Insurers and corporate chief inspectors review the raw NDE evidence, corrosion rates, and engineer sign-off in one place.