Re: Ultrasonic Inspection of Reformer Tubes.

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Re: Ultrasonic Inspection of Reformer Tubes.
Posted by: Richard D. Roberts (PID_163), E-mail: richardr@qi2.com, on May 11, 2000 at 15:06 :
In Reply to: Ultrasonic Inspection of Reformer Tubes. posted by : Ram Iyengar on May 11, 2000 at 14:43:
Dear Ram Iyengar,
Conventional NonDestructive Examination(NDE) inspection techniques such as Ultrasonics (UT) and Eddy Current (ET) currently applied to tubing in process plants are geared to finding creep damage in the form of internal cracking within or accross grain boundries. However, with the trend towards larger tube diameters and longer intervals between turnarounds, the detection of such defects may not allow for sufficient time for forward planning of tube replacements. Also, such ‘end of life’ techniques do not allow any differentiation between the ‘good’ tubes. Early detection of underutilized tube life can prevent the lost opportunity on both unrealized production through running them too cool and tube life ‘giveaway’ if good tubes are discarded prematurely.
Tubes in furnaces, reformers, etc. undergo creep strain, in the form of diametrical growth, from the first day that they are fired. The ability to accurately measure and record this growth means that the tubes’ condition can be monitored from day one. Therefore, not only can individual tubes be retired from service at an appropriate time, but also the component as a whole can be assessed for performance. The use of QUEST Integrated, Inc. internal laser mapping technique is not only useful in preventing tube failures but has huge potential in optimizing production from the whole tube set without sacrificing reliability. Of course, EXTERNAL diameter measurements can be used but they are limited as the automated devices only measure across one diameter and are often access restricted. Manual measurements are too time consuming to provide more than a few readings per tube. Furthermore, neither way can provide diametral growth data at or through the furnaces or reformers refractory. External measurements are inherently less precise as they are based on a crude surface rather than the internal surface and do not take into account the effects of oxide shedding. The most accurate growth measurements are obtained when ‘as new’ baseline data has been taken prior to the tube being fired for the first time.
Recently, the use of the laser mapping method referred to as “laser profilometry” has gained worldwide acceptance as a viable inspection method for the early detection and characterization of creep. Process plants in New Zealand, South America, Canada, and the United States have successfully used the laser profilometry method. Whenever furnace, reformer, etc. tubes are operating under pressure in their creep temperature range, their ID will increase over time.. Use of laser profilometry allows mapping and quantification of a tube’s ID as several hundred thousand diameter readings can be acquired down its length. Since small diameter increases on the tube’s interior (i.e.1% are indications of early stages of creep, it is essential to gather data with such accuracy).
QUEST Integrated, Inc. has developed a laser-based system which provides precise inner diameter dimension down the length of catalyst tubes in reformers. This process has been quite successful in providing data to 3-Dimensional (3D) model steam reformer tubing in several Methanol and Ammonia plants. The advantage is that scale, corrosion, etc. on the tubes exterior has no effect on the data quality. When Eddy Current or Ultrasonics is utilized scale, corrosion, etc. tend to create noise levels which can produce erroneous results. QUEST’s laser method could also be used in your situation as well. If you have interest in knowing more please contact Richard D. Roberts/QUEST at 1-253-872-1275.
Regards,
Richard D. Roberts
-------------------------- origional message -------------
: Gentlemen,
: I need information about Ultrasonic Inspection of Reformer Tubes used in fertilizer plants.
: Information with respect to the above subject will be appreciated.
: regards
: ram iyengar

QUEST Integrated, Inc.

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: Dear Ram Iyengar, : Conventional NonDestructive Examination(NDE) inspection techniques such as Ultrasonics (UT) and Eddy Current (ET) currently applied to tubing in process plants are geared to finding creep damage in the form of internal cracking within or accross grain boundries. However, with the trend towards larger tube diameters and longer intervals between turnarounds, the detection of such defects may not allow for sufficient time for forward planning of tube replacements. Also, such ‘end of life’ techniques do not allow any differentiation between the ‘good’ tubes. Early detection of underutilized tube life can prevent the lost opportunity on both unrealized production through running them too cool and tube life ‘giveaway’ if good tubes are discarded prematurely. : Tubes in furnaces, reformers, etc. undergo creep strain, in the form of diametrical growth, from the first day that they are fired. The ability to accurately measure and record this growth means that the tubes’ condition can be monitored from day one. Therefore, not only can individual tubes be retired from service at an appropriate time, but also the component as a whole can be assessed for performance. The use of QUEST Integrated, Inc. internal laser mapping technique is not only useful in preventing tube failures but has huge potential in optimizing production from the whole tube set without sacrificing reliability. Of course, EXTERNAL diameter measurements can be used but they are limited as the automated devices only measure across one diameter and are often access restricted. Manual measurements are too time consuming to provide more than a few readings per tube. Furthermore, neither way can provide diametral growth data at or through the furnaces or reformers refractory. External measurements are inherently less precise as they are based on a crude surface rather than the internal surface and do not take into account the effects of oxide shedding. The most accurate growth measurements are obtained when ‘as new’ baseline data has been taken prior to the tube being fired for the first time. : Recently, the use of the laser mapping method referred to as “laser profilometry” has gained worldwide acceptance as a viable inspection method for the early detection and characterization of creep. Process plants in New Zealand, South America, Canada, and the United States have successfully used the laser profilometry method. Whenever furnace, reformer, etc. tubes are operating under pressure in their creep temperature range, their ID will increase over time.. Use of laser profilometry allows mapping and quantification of a tube’s ID as several hundred thousand diameter readings can be acquired down its length. Since small diameter increases on the tube’s interior (i.e.1% are indications of early stages of creep, it is essential to gather data with such accuracy). : QUEST Integrated, Inc. has developed a laser-based system which provides precise inner diameter dimension down the length of catalyst tubes in reformers. This process has been quite successful in providing data to 3-Dimensional (3D) model steam reformer tubing in several Methanol and Ammonia plants. The advantage is that scale, corrosion, etc. on the tubes exterior has no effect on the data quality. When Eddy Current or Ultrasonics is utilized scale, corrosion, etc. tend to create noise levels which can produce erroneous results. QUEST’s laser method could also be used in your situation as well. If you have interest in knowing more please contact Richard D. Roberts/QUEST at 1-253-872-1275. : Regards, : Richard D. Roberts : -------------------------- origional message ------------- : : Gentlemen, : : I need information about Ultrasonic Inspection of Reformer Tubes used in fertilizer plants. : : Information with respect to the above subject will be appreciated. : : regards : : ram iyengar

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