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04:52 Apr-24-2006

rpbhan

Engineering,
HPCL Refinery,
India,
Joined Jul 2003
11
Inspection of Reformer tubes in H2 generation units

I will like to know are there any techniques or methods in addition to Ultrasonic attenuation ( Auto UT ) which can be taken as firm inputs for deciding the replacement of Reformer tubes . Laser ID or Eddy current from tube ID is out as catalyst is not being removed at every outage . Magnetic permeabilty or OD measurement for bulging or Insitu-metallography may not be either reliable or may give indications at very late stage to take decision for replacement . Is there any role for X ray in detecting mid-wall fissures in early stages ?


 
03:52 Apr-26-2006

Rich Roberts

Engineering, Executive Managment
Quest Integrity Group,
USA,
Joined Nov 1998
78
Re: Inspection of Reformer tubes in H2 generation units Good Day,

The LOTIS technology which can be applied either EXTERNALLY or INTERNAL to inspect the centrifugally cast tubes in the steam reformer. The “external” LOTIS crawler system was developed over the last 4 years and only recently commercialized in 2005, while the “internal” LOTIS system has been examining tubes in steam reformers for nearly 10 years. These technologies have logged well over 100,000 steam reformer tube inspections. Destructive testing on dozens of tubes have been carried out to confirm the methodology.

Both the internal and external LOTIS services are provided by Johnson Matthey Catalyst (JMC) out of the UK. Contact Mr. Barry Fisher at barry.fisher@matthey.com for more details.

Regards, Rich
Quest TruTec
----------- Start Original Message -----------
: I will like to know are there any techniques or methods in addition to Ultrasonic attenuation ( Auto UT ) which can be taken as firm inputs for deciding the replacement of Reformer tubes . Laser ID or Eddy current from tube ID is out as catalyst is not being removed at every outage . Magnetic permeabilty or OD measurement for bulging or Insitu-metallography may not be either reliable or may give indications at very late stage to take decision for replacement . Is there any role for X ray in detecting mid-wall fissures in early stages ?
------------ End Original Message ------------




 
08:30 Apr-27-2006

Jason Taylor

Consultant
Oceaneering,
United Kingdom,
Joined Jul 2002
5
Re: Inspection of Reformer tubes in H2 generation units ----------- Start Original Message -----------
: I will like to know are there any techniques or methods in addition to Ultrasonic attenuation ( Auto UT ) which can be taken as firm inputs for deciding the replacement of Reformer tubes . Laser ID or Eddy current from tube ID is out as catalyst is not being removed at every outage . Magnetic permeabilty or OD measurement for bulging or Insitu-metallography may not be either reliable or may give indications at very late stage to take decision for replacement . Is there any role for X ray in detecting mid-wall fissures in early stages ?
------------ End Original Message ------------

When we last inspected the Hydrogen reformer tubes on our site we used a firm called IESCO based in California, their system carried multiple test techniques. From memory this was UT ET and physical measurement all carried out by a tube crawler unit externally. This was the only company at the time who had a unit small enough to fit between our tubes as many had buckled somewhat in use. Radiography would probably be out due to the Catalyst in the tubes




 
05:46 Apr-27-2006

Rich Roberts

Engineering, Executive Managment
Quest Integrity Group,
USA,
Joined Nov 1998
78
Re: Inspection of Reformer tubes in H2 generation units Hello Jason,

The LOTIS external crawler is the most compact and light weight crawler on the market today. The sytem is built so that the sensors actually go into the floor and roof penetrations to enable maximum tube coverage. The LOTIS inspection method inspects 100% of the circumference, rather than 50-60% which the ET & UT crawlers do. Please advise if you would like additional details.

Regards, Rich

----------- Start Original Message -----------
: : I will like to know are there any techniques or methods in addition to Ultrasonic attenuation ( Auto UT ) which can be taken as firm inputs for deciding the replacement of Reformer tubes . Laser ID or Eddy current from tube ID is out as catalyst is not being removed at every outage . Magnetic permeabilty or OD measurement for bulging or Insitu-metallography may not be either reliable or may give indications at very late stage to take decision for replacement . Is there any role for X ray in detecting mid-wall fissures in early stages ?
: When we last inspected the Hydrogen reformer tubes on our site we used a firm called IESCO based in California, their system carried multiple test techniques. From memory this was UT ET and physical measurement all carried out by a tube crawler unit externally. This was the only company at the time who had a unit small enough to fit between our tubes as many had buckled somewhat in use. Radiography would probably be out due to the Catalyst in the tubes
------------ End Original Message ------------




 
04:09 Apr-29-2006
Brian Shannon
Re: Inspection of Reformer tubes in H2 generation units ----------- Start Original Message -----------
: I will like to know are there any techniques or methods in addition to Ultrasonic attenuation ( Auto UT ) which can be taken as firm inputs for deciding the replacement of Reformer tubes . Laser ID or Eddy current from tube ID is out as catalyst is not being removed at every outage . Magnetic permeabilty or OD measurement for bulging or Insitu-metallography may not be either reliable or may give indications at very late stage to take decision for replacement . Is there any role for X ray in detecting mid-wall fissures in early stages ?
------------ End Original Message ------------

Cast materials in Reformer Units undergo degradation over tme and are subject to damage accumulation through plant operational variations. As such damage can occur at any stage of life. To determine the correct condition and life consumption of furnace tubes,NDE is applied during shutdowns.
The important thing to remember when considering an inspection of these tubes is the effectiveness of the approach being considered. It has been demonstrated that due to the nature of the varing degrees and locations of damage,no one technique will cover all of the areas that need to be assessed for an effective inspection. To simply assume that by measuring creep strain by whatever method ,be it laser,lift off sensors or simple stapping, or again by applying Eddy current as stand alone techniques, one can achieve a meaningfull inspection is incorrect. Various sensors must be employed and directed at all of the damage areas to garner sufficient information for a quantative assessment of tube life.
To that end IESCO developed the H SCAN approach which utilizes ultrasonic,eddy current and tube profiling(OD / ID measurements and wall thickness)to provide a complete inspection and condition assessment. Combined with custom software which accepts the inspection information directly and using plant operating information ,a remaining life prediction can be provided.
This approach has been adopted by many plant operators worldwide. For further detains please contact me at the address noted.



 
05:38 May-06-2006
SUNIL BIRLA
Re: Inspection of Reformer tubes in H2 generation units Mr. Rich
The H-scan by M/s IESCO covers scanning by Ultrasonic Attenuation, Profilometry OD , Eddy current and wall thickness. They say that "Tube condition cannot be determined by one stand-alone technique, as the degree of damage within a particular tube may not lend itself to that specific NDE technique. The reliability of NDE evaluation of reformer furnace tube condition can be improved by combining a variety of advanced NDE techniques ('H' SCAN Technology) that individually monitor differing physical parameters. The advantages and disadvantages of each technique, when compared against each other, reduces the occurrence of false calls, improves tube condition assessment and can increase overall furnace reliability."
How do you compare LOTIS with H-scan of M/s IESCO.


---------- Start Original Message -----------
: Good Day,
: The LOTIS technology which can be applied either EXTERNALLY or INTERNAL to inspect the centrifugally cast tubes in the steam reformer. The “external” LOTIS crawler system was developed over the last 4 years and only recently commercialized in 2005, while the “internal” LOTIS system has been examining tubes in steam reformers for nearly 10 years. These technologies have logged well over 100,000 steam reformer tube inspections. Destructive testing on dozens of tubes have been carried out to confirm the methodology.
: Both the internal and external LOTIS services are provided by Johnson Matthey Catalyst (JMC) out of the UK. Contact Mr. Barry Fisher at barry.fisher@matthey.com for more details.
: Regards, Rich
: Quest TruTec
: : I will like to know are there any techniques or methods in addition to Ultrasonic attenuation ( Auto UT ) which can be taken as firm inputs for deciding the replacement of Reformer tubes . Laser ID or Eddy current from tube ID is out as catalyst is not being removed at every outage . Magnetic permeabilty or OD measurement for bulging or Insitu-metallography may not be either reliable or may give indications at very late stage to take decision for replacement . Is there any role for X ray in detecting mid-wall fissures in early stages ?
------------ End Original Message ------------




 
08:24 May-08-2006

Rich Roberts

Engineering, Executive Managment
Quest Integrity Group,
USA,
Joined Nov 1998
78
Re: Inspection of Reformer tubes in H2 generation units Good Day Mr. Sunil Birla,

As I'm sure NDT.net would appreciate, I would prefer to illustrate comparison of NDE methodologies, rather than service trade names and/or suppliers. As I¡¯m sure you are aware, tubes operated in Steam Reformers are manufactured with unique spun cast, high alloy materials. Typical materials in this application are made up of 25% Chrome, 35% Nickel and other miscellaneous components. Both chrome and nickel are large grain, as compared to other elements. The combinations of these variables create a significant challenge for conventional NDE methodologies (i.e. Eddy Current and Ultrasonics).

ULTRASONICS (UT)
Application of the Ultrasonic Testing (UT) methodology to obtain the most simple thickness reading in spun cast, high alloy materials are obtain challenging as a ¡°very noise¡± response is produced. In steam reformer tubes it¡¯s quite challenging to obtain thickness reading due to the large grain material and grain orientation, unless a UT frequency of ¡Ý1-2 MHz is applied. As the frequency is lowered, below the most commonly applied ultrasonic frequency (2.25 ¨C 5 MHz), resolution is sacrificed. To even further challenge the application of UT in stream reformer tubes, if one attempts to apply a ¡°through transmission¡± (pitch catch) technique (2 transducers, one transmitting and one receiving) there is now twice the complication as the tube surface profile (remember steam reformer tubes have a very rough ¡°as cast¡± surface) creates more noise (each transducer has it own set of surface profile problems), ultimately impacting test data result accuracy. At the conclusion of the UT test, NDT inspectors are attempting to pick creep strain damage out of incredibly noise UT test data, ultimately resulting in operator misinterpretation and quite commonly ¡°false calls¡± or ¡°no detection¡± of existing creep strain damage.

EDDY CURRENT (ECT)
The Eddy Current Testing (ECT) test methodology is severely compromised when materials properties vary over the length of the tube. Because steam reformer tubes operate in an environment which result in significant permeability variations from top of tube to the bottom, this factor play a significant roll test results. When the permeability properties change down the length or circumference of a given steam reformer tube the reaction of eddy currents within the spun cast, high ally material will be compromised, producing ¡°erroneous results¡±.

LASER
The laser method¡¯s test results are ¡°not¡± compromised if permeability changes are present any where within the tube, surface profile is rough or material is made of large grain alloys (i.e. Chrome, Nickle, etc.). The laser is being applied to measure ¡°strain¡± which is then modeled to generate 3-Dimensional models of the entire reformer. In addition to the models the laser data is now being applied to calculate ¡°remaining life¡± within a tube. Remaining life considers laser data results (stain measurement), tube age, material, thermal cycles, etc..

Regardless if oneor several combined conventional NDE technologies (UT, ECT, etc.) are applied, if erroneous test results are generated as a function of material type (i.e. 25% Chrome / 35% Nickel), manufacturing process (i.e. spun cast) and operating inviroment, most likely the tube inspection results will either result in ¡°False Calls¡± on perfectly good tubes or simple ¡°missed detection¡± of creep strain damage on tubes which should have removed from the reformer.

To further validate use of the Laser methodology it may be best for you to speak directly with several steam reformer owner/users. A reference list with dozen¡¯s of plant references for the use of laser based technology can be provided. If you have interest in speaking with plant Owner Users which have carried out ¡°side by side¡± comparison of the Laser Technology to: (1) Eddy Current, (2)Combined Eddy Current and Ultrasonic or (3) Ultrasonic we will be happy to forward you that information.

Regards, Rich Roberts




 
06:25 May-10-2006
Brian Shannon
Re: Inspection of Reformer tubes in H2 generation units ----------- Start Original Message -----------

I think it is important to stay on point when discussing the techniques that are used to determine the condition of these reformer tubes.
Let us take a true look at how one might develope an effective inspection for a particular type or types of damage.
In reformer tubes the damage has a variety of manifestations; internal creep void formation,microcracking and macrocracking. However there are other issues;external cracking resulting from thermal shock and operational upsets,weld cracking resulting from differing ductility properties between weld and base materials.
In each case the detection and quantification of the degree of damage will depend on the sensitivity of a particular method of NDE.
To assert that in each case the damage whatever it's nature can be determined by simply measuring the tube diameter, however sophisticated the presentation,is indeed presumptuous and incorrect.
Let's look at each class of damage: early creep void formation and microcracking toward the inner one third of the tube wall thickness.This level of damage may or may not be accompanied by changes in creep strain values(changes in diameter) .The only technique that will detect this level of damage is a specialized ultrasonic examination focussed at the area where the damage will show up.
Let's look at non radial cracking or external cracking resulting from furnace upset and thermal shock ;this type of damage will certainly not exibit any change in strain values. It is only by applying a bespoke eddy current system and procedure will one be able to detect and quantify the degree of damage.
Certainly changes in tube diameter effect the life of a tube but only as it relates to the change in tube dimensions and the resultant stresses from hoop, cyclic and thermal stresses.
Damage can occur in tubes to a severe extent without any change in strain (diameter) values. Conversely tubes can exibit high degree of tube strain changes (6% - 8%) with minimal internal damage.

As I mentioned previously only by applying a multiple technique approach can one increase the overall effectiveness (90%)of the inspection. Relying on a tube measurement methodolgy however simplistic or seductive will only render a limited inspection effectiveness (10%)as it is only measuring one parameter of the tube condition.
: Mr. Rich
: The H-scan by M/s IESCO covers scanning by Ultrasonic Attenuation, Profilometry OD , Eddy current and wall thickness. They say that "Tube condition cannot be determined by one stand-alone technique, as the degree of damage within a particular tube may not lend itself to that specific NDE technique. The reliability of NDE evaluation of reformer furnace tube condition can be improved by combining a variety of advanced NDE techniques ('H' SCAN Technology) that individually monitor differing physical parameters. The advantages and disadvantages of each technique, when compared against each other, reduces the occurrence of false calls, improves tube condition assessment and can increase overall furnace reliability."
: How do you compare LOTIS with H-scan of M/s IESCO.
:
: ---------- Start Original Message -----------
: : Good Day,
: : The LOTIS technology which can be applied either EXTERNALLY or INTERNAL to inspect the centrifugally cast tubes in the steam reformer. The “external” LOTIS crawler system was developed over the last 4 years and only recently commercialized in 2005, while the “internal” LOTIS system has been examining tubes in steam reformers for nearly 10 years. These technologies have logged well over 100,000 steam reformer tube inspections. Destructive testing on dozens of tubes have been carried out to confirm the methodology.
: : Both the internal and external LOTIS services are provided by Johnson Matthey Catalyst (JMC) out of the UK. Contact Mr. Barry Fisher at barry.fisher@matthey.com for more details.
: : Regards, Rich
: : Quest TruTec
: : : I will like to know are there any techniques or methods in addition to Ultrasonic attenuation ( Auto UT ) which can be taken as firm inputs for deciding the replacement of Reformer tubes . Laser ID or Eddy current from tube ID is out as catalyst is not being removed at every outage . Magnetic permeabilty or OD measurement for bulging or Insitu-metallography may not be either reliable or may give indications at very late stage to take decision for replacement . Is there any role for X ray in detecting mid-wall fissures in early stages ?
------------ End Original Message ------------




 
03:39 Jun-18-2006
Ikesh Patel
Re: Inspection of Reformer tubes in H2 generation units Dear Mr.Birla,
Can you please tell me the specific material of the tube and tube condition (Cleaniness) and what problem you are expecting in the tubes , so that I can suggest you the roper technique.
Thanks.
Ikesh Patel.


 
06:56 Jul-29-2006
Jayapal
Re: Inspection of Reformer tubes in H2 generation units Go for H-scan inspection. The same was done by RIL at Jamnagar by IESCO, USA. In one of IOCL refineries it is being planned.


 


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