The definition of Replacement in Kind according to OSHA’s Standard 1910.119(b) means a replacement which satisfies the design specification. (1)
When planning to replace or upgrade critical heat exchanger equipment with a Management of Change (MOC) for a long-term production run, many factors come into play in choosing the best path forward. Some questions must be asked and answered:
- How did the previous heat exchangers perform?
- Did the original metallurgy stand up to the process?
- Have there been any process changes that would alter future performance?
- Will an upgrade in metallurgy improve reliability, reducing future corrosion issues and unscheduled shutdowns to repair tube leaks?
- How can we get to the next scheduled TAR with the best allocation of assets?
In most cases, the MOC engineering package from the last turnaround will be investigated to determine how the exchanger functioned and any issues that arose. With heat exchanger equipment, the decision is to use the original carbon steel tube material is an easy one but is not always the most effective and reliable for its intended service. Carbon steel tubes may work adequately in certain applications where the process is not corrosive and fouling is kept to a minimum, however many critical heat exchangers in service experience significant wall loss due to various forms of severe corrosion, cracking and fouling that deprives the exchanger’s efficiency.
An upgrade in tubing metallurgy is routinely considered but the high cost of alloyed tubes can be cost prohibitive. An alternate solution is available and has been part of MOC and FEED/FEL engineers’ decision making for nearly three decades. CTI’s thin-walled Full Length Tube Liners have been a cost effective and reliable solution to short-lived carbon steel tubes. CTI Liners are available in a variety of stainless steel and nickel alloy materials that can be installed in both new and existing damaged heat exchanger tubes.
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CTI Full Length Tube Liners installed in new heat exchanger equipment will add an initial expenditure to budgeting for the next turnaround, however the cost of keeping the original carbon steel tubes in your work scope could cost significantly more down the road when unexpected tube leaks force emergency shutdowns or create safety and environmental implications.
It is becoming the norm when routine equipment inspections performed to regularly monitor the condition of the carbon steel tubes turns into frantic emergency repair or a re-tube situation. The anticipated corrosion/pitting of the carbon steel tubes often has accelerated beyond anyone’s expectations and cannot be put back into service as is. The scenario has become more common place with changes in crude quality and/or operational process management.
CTI receives heat exchanger drawings on a regular basis from clients looking for solutions to their tube damage. We are seeing “born on” manufacture dates on these drawings that are only two to three years old.
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Several years ago, CTI installed tube liners into four NEW crude overhead shell and tube exchangers for a Gulf Coast refinery. The refinery managers knew from past practice that they could not sustain a 5-year uninterrupted run without tube leaks using carbon steel tubes, no matter how thick they made the tube walls. Tube leaks were inevitable; so the decision was made to have the four new exchangers built at an OEM shop. This refinery’s previous experience with CTI Full Length Tube Liners in air cooled exchanger tubes over the course of a decade led them to think out-of-the-box and use CTI’s Liners in the shell and tube crude units to get the five-year-run they were looking for.
Looking beyond the base-line TAR budgeting, CTI’s Full Length Tube Liners may be considered an upsell to management. If you consider the true costs of what is involved with a forced shut down or hazardous safety concerns, CTI Liners’ long-term reliability should be given serious consideration to combat tube failures in critical heat exchanger equipment.
Achieving maximum performance and reliability from your critical heat exchanger equipment is not only possible, it’s actually happening right now. Liners can be considered a permanent repair or upgrade as they can be inspected with standard NDT methods. CTI can provide calibration standards comprised of liner samples installed into parent tubes. Baseline and follow-up inspections can be routinely performed to monitor the liners’ effectiveness.
CTI Industries has over 40 years of experience increasing the reliability of heat exchanger tubes in over 50 countries around the world. Whether in newly designed exchangers or in existing damaged/leaking tubes, CTI Full Length Tube Liners can not only restore previously plugged tubes back to service, they will also extend the life of your exchanger and can improve efficiency by reducing fouling that commonly occurs in carbon steel.
The definition of insanity is doing the same thing time and time again while expecting different/better results. It is always easier to use the “replace in kind” thought process, but when you know that tube failure is inevitable, CTI Liners can be your solution.
For more product information, please visit www.cti-ind.com.
