SMART PIG INSPECTION OF FIRED HEATER PROCESS TUBES

Merlin Inspection Technology

This technology has progressed through scientific research and development since the late 1990s.  The result has been steadily improving stages of capability, performance and reliability.  The most recent achievement stage is the Mark IV, which successfully entered commercial service during 2012.

Once the decoking operation has been completed, the Merlin Intelligent Pig is driven by water through the internal passageway of a pass or coil.  The Merlin Intelligent Pig uses sophisticated ultrasound technology to internally scan fired heater tubes, recording and identifying measurements and internal surface condition.  The current development stage is proven to allow passage through box/plugged headers without modification.  Using a single body of specially prepared composite material, Merlin Mark IV technology is designed to have narrow passageway capability and has been used in tube circuits which include box headers featuring a central crossover passage with 3” diameter.

Navigating through 180° u-bends is even easier!  The new Mark IV Intelligent Pig can pass through 3” schedule 160 tubes which have an internal diameter of 2.6 inches (66.7mm).

Merlin Tube Inspection

Key Features of Merlin Intelligent Pig

  • Bi-directional single body
  • Able to pass through box/plugged headers (mule ears) unaided
  • Able to inspect any grade of steel including stainless, CrMo, cast, incology etc.
  • Custom designed bespoke piezo-composite transducers
  • Up to 11700 wall thickness and internal radius measurements taken per foot
  • Automated data analysis and defect detection

Advantages of a Merlin Inspection

  • Combined Service of decoking and tube inspection
  • Inspection technicians work together with decoking operators to increase the efficiency of cleaning operations
  • Multiple inspections carried out per pass for data validation, at no extra cost to client
  • Ability to inspect convection coils
  • Proven ability to inspect furnaces containing box/plugged headers (mule ears)
  • Data coverage significantly higher than alternative UT methods

Advantages of Smart Pigging over handheld UT

  • Huge increase in data coverage
  • Ability to inspect convection coils
  • Quicker
  • Abilities to detect localised defects
  • Ability to detect creep damage

What can Merlin inspect?

  • Fired heaters including Visbreakers, Delayed Cokers, Vacuum Furnaces, Crude Furnaces, Reboilers and Heli Coils
  • HRSG Units
  • OTSG Units

Merlin Smart Pig Specifications

  • Internal tube diameter range: 2.6 – 12″
  • Wall thickness static accuracy: 0.012″
  • ID accuracy: ±0.75% (full scale)
  • Axial location accuracy: 2.4″ (typical)
  • Resolution: 0.3″ (axial) x 0.5″ (circumferential) typical
  • Data sampling rate: 60Hz
  • Number of transducers: 16 (3 – 5″) 32 (6 – 12″)
  • Number of measurements per sample: 128 (3 – 5″) 256 (6 – 12″)
  • Transducer centre frequency: 5MHz
  • Battery life before recharge: 8 hours
  • Running speed: 1.0 – 3.0FPS
  • A-scan recording for every measurement

Defect Detection and Classification

  • Metal loss (distinction between internal and external)
  • Bulging
  • Ovality
  • Diametric growth or swelling
  • Dents
  • Fretting
  • Internal fouling
  • Axial AND circumferential anomaly location
  • Level 1 & 2 assessments in accordance with API 579-1/ASME FFS-1-fitness for service

Coke Detection

  • Coke and internal fouling can be accurately located and quantified.
  • Inspectors can advise decoking operators where coke is located to optimise decoking efficiency.
  • Hot spots will be identified.
  • Tube inspection is the only ‘true’ way of assessing if process tubes are internally clean.

Fast & Reliable Reporting

  • Any anomalies identified when still on site will be reported ASAP.
  • Field report issued within 24 hours of final inspection run (including quantification and location of any anomalies).
  • Final reports are always issued within one week.
  • Each Merlin inspection final report includes a full written summary of findings, data tables, linear graphs (for each tube) and C-scans.
  • Fully interactive 3D-C-scans and software are issued to the client, enabling them to quickly and accurately locate areas of concern.
  • Feature of the 3D software include: 360° rotations and panning, 3D models for WT, IR, ID, OR, OD and internal fouling, zoom function and metric or imperial scale options.

Contact our Merlin Inspection Team today with your enquiry.

Tube Inspection technical contacts UK:
David Thewsey | John Farrell | +44 (0)1244 531 765

Tube Inspection technical contact USA:
Robert Williams | +1 281.537.7475

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