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Heat Exchanger – Unblocking Hairpins in Titanium U-Tube Heat Exchangers for Gas Liquefaction Company

Bespoke water jetting cleans titanium heat exchanger from Arabia

Summary

An Arabian gas liquefaction company shipped a titanium U-tube (hairpin) heat exchanger to Tube Tech’s UK head office so that Tube Tech could remove calcium carbonate and tenacious silicate deposits from within the fragile tubes thus increasing the heat exchangers efficiency.

Challenge

While long-lasting in terms of operational life, even titanium heat exchanger tubes become blocked.
The item, transported by sea to Tube Tech, was heavily blocked around the hairpins with calcium carbonate and tenacious silicate deposits which had contributed to a loss of heat transfer abilities.
Tube Tech was contracted because the heat exchanger had very long tubes and the company has a reputation for being successful with difficult heat exchanger cleaning projects.
Titanium tubes, while having excellent heat transfer properties, are thin and soft and require more than usual delicacy while cleaning.

Solution

A multi-phase heat exchanger cleaning approach was devised which started with a low-volume 60,000 PSI (4,000 BAR) water jetting system utilising intelligent metal lances which conformed to the shape of the tubes while drilling and jetting simultaneously.
As acid-type chemicals are not recommended on titanium, a biodegradable wash was used to remove traces of scale from the tube walls once a bore was created.
A miniature rotating Dartt was fired around the bend before a video probe sent back a 3D image to confirm no damage to interior bores.
An alternative heat exchanger cleaning system to shatter the scale was being simultaneously developed if the procedure was unsuccessful.
Careful use of bespoke jets and turbines and the lack of aggressive acids meant the titanium suffered no damage and was polished to a pristine condition after the heat exchanger cleaning was completed.

Client Comment

A spokesperson for the client said: “We were very satisfied with the standard of clean achieved. We had tried drilling, high-pressure jetting at 1,000BAR and various chemicals with no joy. Our objective was unblocking 5% of tubes to reach satisfactory performance. Tube Tech achieved 7% and promised to attain 95%-plus if required. This avoided a full and expensive retube costing at least $250,000. We will have no hesitation in calling in Tube Tech again.”

Tube Tech Comment

Mike Watson, Managing & Technical Director: “The hairpins were solidly blocked. This level of blockage and hardness factor has always previously meant a re-tube or full replacement. We had to take great care because the heat exchanger was titanium, perhaps the only one of its type that has been done in this manner.”

Due to Bespoke Intellectual Property being used Tube Tech International Ltd are happy to demonstrate and discuss the unique U tube heat exchanger cleaning process if further information is required.

Clients can be contacted via Tube Tech for references.

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