This document discusses reformer tube inspection tools and issues affecting tube life. It describes an internal and external inspection system that uses laser scanning and eddy current testing to detect cracks, measure diameter expansion, and monitor creep damage in reformer tubes. Local issues like overheating, thermal shocks, and catalyst fouling can be identified. Comprehensive inspection reports are generated with results for each tube. The non-destructive testing helps assess tube condition and remaining life.

1. Issues Affecting Tube Life
&
Reformer Tube Inspection
Thomas Fortinberry SME
KontrollTechnik GmbH
Testing of Reformer Tubes by Internal and External Inspection Tools

2. Introduction
Testing of Reformer Tubes by Internal and External Inspection Tools
One of the most important tasks for a
reliable operation of reformer furnaces
is the integrity of the reformer tubes.
The early detection of creep damage and
micro-cracks using the Reformer
Pipe Scanner (RPS 360)
proprietary OD and ID inspection
systems can lead to improved reformer
tube knowledge and operation. The
diameter is measurement by laser for
expansion and is performed
simultaneously with our proprietary
360° crack detection system.

3. Tube Pinching
Testing of Reformer Tubes by Internal and External Inspection Tools
Isolated hot spots and tube ruptures can
occasionally develop on radiant tubes
during operation. Rather than shut the
furnace down to replace these isolated
tubes, the tubes are externally pinched
at their inlet and outlet pigtail without
shutting down the furnace. The only way
is to do hot crimping at both inlet and
outlet pigtail tube ends of the damaged
reformer tubes when in service. After
this the tube has no flow to absorb the
energy and the outside of the tube
becomes overheated. This affects the
neighboring tubes and causes elevated
temperatures thus creating more
overheating. This over heating can affect
the complete circumference of the tube.
Overheated Pinched Tubes

4. Local Overheating
Testing of Reformer Tubes by Internal and External Inspection Tools
Flame impingement can happen for a number
of reasons for example, misaligned burners
this is when the flame deviated from the
vertical position and the flame impinges on
the tube surface. Flue gas mal-distribution
happens when the flu gas is moved from the
normal flow pattern and can impinge on the
tube this can happen on the hot or cold face.
Insufficient combustion air on one row of
burners can lead to excessively high flame
temperatures which can cause the tube to
overheat. All of these can lead to local flame
impingement, this not only affects the fire
side of the tube but also the non-fired sides
of the tubes.

5. Reformer Tube Issues & Inspection Solution
Testing of Reformer Tubes by Internal and External Inspection Tools
Thermal shock is very damaging to tube life, it
can even cause catastrophic effects to the
whole reformer. When you experience a
thermal shock it is important to perform an
inspection and check for damage. Any damage
that occurred during the excursion should be
evaluated carefully, due to the rapid damage all
indications are of importance. Here are some
examples of damages from thermal shock, as
you can see these were catastrophic failures
but also note they didn’t just fail on the main
fire side. After this type of event it’s imperative
to perform a 360° inspection and not just focus
the fired side of the tube but you want to
inspect the whole tube for damage.

6. Catalyst Fouling of Reformer Tubes
Testing of Reformer Tubes by Internal and External Inspection Tools
Typically giraffe necking is caused by
the catalyst being poisoned from the
natural gas entering the reformer
tube that has impurities, it is
normally the up-stream zinc oxide
bed that is the root cause, allowing
mercury and other impurities to
enter the feed. As you can see in the
pictures this causes local hot spots
on the tubes and not always just on
the main fired side but can be found
anywhere along the circumference
of the tube.

7. Reformer Tube Issues & Inspection Solution
Testing of Reformer Tubes by Internal and External Inspection Tools
RPS 360
• Identifies failure mechanisms in
individual tubes:
o Creep strain (most prevalent
failure mechanism)
o Bulging
o Swelling
o Manufacturing flaws
• Early warning of problems
before tube failure
• Provides baseline
measurements for new tubes to
determine condition before
tubes are put in-service
Overheated Tubes

8. Crack Detection
Testing of Reformer Tubes by Internal and External Inspection Tools
With our newly developed Proprietary
crack detection system we are able to
scan 360° of the tube circumference and
the complete thickness of the wall. The
current systems available for tube wall
scans were developed over 30 years ago
and only offer minimum coverage of tube
wall (less than 30%)
Both measurements strain and crack
detection are carried out simultaneously
during the inspection. During each tube
inspection millions of data points are
collected on each tube.

9. Solution
Testing of Reformer Tubes by Internal and External Inspection Tools
RPS 360 OD
• 100% OD coverage of each reformer
tube with our 360° crack detection
• 6-point laser inspection over entire
length of inspected tube
• Collects millions of data points
during each tube inspection
• Repeatable, accurate and fast
inspection

10. Structure of the External Reformer Tube Inspection System
Testing of Reformer Tubes by Internal and External Inspection Tools

11. Testing of Reformer Tubes by Internal and External Inspection Tools
Technical Features of the External Tube Scanner RPS 360 OD
Tube Diameter Range : 80 – 155 mm adjustable
Length : 692 mm
Drive Motors : 4 pcs. electric drive motors
Driving Speed : approx. 300 mm/sec
Drive Control : manual or automatic mode
Max. Vertical Driving Length : up to 16 m adjustable
Minimal Gap between Adjoined
Tubes : 40 mm
Number of EC – Probe Channels: 2 to 16 depending on Tube
diameter
Max. Testable Wall Thickness : 23 mm
Detection Capacity : notch <30% at the Tube
inside wall
Number of Laser Channels : 3x 2 Laser Modules spaced
60° on the Tube circum-
ference.
opposed sensor modules are
connected in differential mode to
compensate radial displacement.

12. ID Inspection
Testing of Reformer Tubes by Internal and External Inspection Tools
RPS 360 ID
• 100% laser ID coverage of each
reformer tube
• 100% crack detection coverage of
each reformer tube
• Collects millions of data points
during each tube inspection
• Repeatable, accurate and fast
inspection

13. Testing of Reformer Tubes by Internal and External Inspection Tools
Structure of the Internal Reformer Tube Inspection System

14. Testing of Reformer Tubes by Internal and External Inspection Tools
Technical Features of the Internal Tube Scanner RPS 360 ID
Technical Features:
Tube Diameter Range : 80 – 170 mm adjustable
Length of Rotating Probe : 592 mm (incl.sensor head)
Rotating Speed : up to 600 rpm
Axial Drive Mechanism : compact wheel mechanism with
free-wheeling for fast probe
insertion
Axial Driving Speed : up to 10 m/min adjustable
Drive Control : manual or automatic mode
Max. Vertical Driving Length : up to 20 m adjustable
Number of EC – Probe Channels : 1
Max. Testable Wall Thickness : 23 mm
Detection Capacity : notch <30% deep at the Tube
outside wall
Number of Laser Channels : 1

15. Result Evaluation and Documentation
Testing of Reformer Tubes by Internal and External Inspection Tools
The Result Documentation consists of:
▪ Inspection Report
description of the project and overall inspection result
▪ Result Data Overview
tabulating the comprehensive inspection result (crack testing and expansion
measurement) for each tested reformer tube
▪ Result Crack Testing
showing the position and statistic distribution of tubes with crack indications
▪ Result Expansion Measurement
showing the position and statistic distribution of tubes with diameter expansions
▪ Sample Report for each Tested Tube
showing the the result of the crack testing and expansion measurement in
graphic form
▪ Remaining Life Assessment
Kontrolltechnik GmbH uses different suppliers for Remaining Life Assessment

16. Result Evaluation and Documentation
Testing of Reformer Tubes by Internal and External Inspection Tools
Results Data Overview
The Result Data Overview shows in a comprehensive form the inspection result (crack testing & expansion
measurement) with min., max. and mean diameter for each tested reformer tube and each tube section.

17. Testing of Reformer Tubes by Internal and External Inspection Tools
Result Evaluation and Documentation
Results Crack Testings
The Result Crack Testing is showing the position and statistic distribution of tubes with crack indications

18. Testing of Reformer Tubes by Internal and External Inspection Tools
Result Evaluation and Documentation
Results Expansion Measurement
The Result Expansion Measurement is showing the position and statistic distribution of tubes with
expansions

19. Testing of Reformer Tubes by Internal and External Inspection Tools
Result Evaluation and Documentation
Sample Report for each Tested Tube
EC-Testing:
▪ eddy current result
presentation in color
scan mode for the entire
tube circumference
▪ easy indentification of
defects
Features Laser Testing
▪ Evaluation of min., max.
and mean diameter for
each tube section at 3
circumferential positions
(only for external reformer
tube testing)
▪ Comparison of max.
diameter to nominal and/or
mean diameter for each
tube section
▪ Comparison of data with
previous or fingerprint laser
testing data (optional)

20. KontrollTechnik GmbH
Im Laab 23
D-29690 Schwarmstedt
Tel. +49 05071 / 9815-11
Fax +49 05071 / 3610
Web www.kontrolltechnik.com
Web www.kontrolltechnik-us.com
Email T.Fortinberry@kontrolltechnik.com
Thomas Fortinberry
Reformer SME
Business Development Director
SLOFEC® Prüfung erdverlegter Leitungen - Stand 2018