Critical path Texas Tower back online in 2.5 days
Tube Tech faced several challenges winning the contract to clean a Vertical Combined Feed Exchanger (VCFE) otherwise known as a Texas Tower feed effluent heat exchanger at a petrochemical plant in central France . The client wanted a fast but effective clean without the waste generated by traditional methods.
- Clearly pulling a tube bundle of this size for conventional HP water jetting would only be considered as a last resort so there is a big incentive to do in-situ cleaning if there is evidence of significant fouling.
- Typical fouling deposits on the combined feed (tube) side in no particular order could be scale, debris, iron sulphide, iron chloride ammonium chloride and gums.
- Typical fouling deposits on the reactor effluent (shell) side in no particular order could be polynuclear aromatics (eg. resins), ammonium chloride and catalyst dust.
- The Texas Tower in the platformer unit is invariably on the critical path and is a vital part of the operation but 10% of its 3,500 tubes were blocked by a hard, compacted scale.
- Because lost production is costly in the oil industry Tube Tech was set the task of speeding up the cleaning of the 18-metre long tubes which have an 11.8mm internal diameter.
- Safety and cost effectiveness were paramount.
- Chemical waste, an unwanted by-product of traditional cleaning methods, also had to be reduced.
- Use of high-pressure water jetting lances in the past had been a lengthy process and created dangerous hydraulic action within such small tubes. Neither chemicals nor water jetting had provided a solution to clearing the heat exchanger tubes.
- As no chemicals were to be used the Tube Tech team developed it’s very own 7mm to 8 mm high-pressure micro lance system manufactured under license.
- Tube Tech’s own lance-feeding mechanism, because of its versatility, was able to accept the various diameters and lengths of lances.
- A mix of ceramic and spinning darts were also used in conjunction with Tube Tech’s Rotaflex system and rotating “Soft drill”.
- Tube Tech achieved the required high standard of cleaning in just 3 days, representing a time saving of 75% on methods used by other traditional contractors which normally takes up 10 days.
- With downtime running into hundreds of thousands of dollars a day, this was a vital cost-saving for the client.
- The work was carried out safely because very little high-pressure equipment was utilized and, without chemicals, no noticeable waste was generated.
- Tube Tech’s trained confined space team used breathing apparatus to avoid inhalation of dust or vapor.
Tube Tech Comment
Mike Watson, Technical and Managing Director: “We won the contract on our proven track record for innovation in this field. With this particular contract we were challenged to develop a process that was faster, cleaner, safer, more cost-effective and produced less waste. The day before we mobilised, we were advised that a cleaning contractor had achieved a clean in 7 days in Australia so we were up against it from the start. With a few adjustments we not only achieved all our goals but exceeded the client’s expectations. As with all projects, valuable lessons were learnt and now feel confident we can clean similar sized VCFE’s in less than 2 days.”
A spokesman for the client said: “Historically, attempts using high-pressure jetting have taken up to 10 days to clean Texas Tower tubes. TTIL achieved a result beyond expectations and completed the project in 2.5 days and certainly lived up to my expectations. Lengthy downtime would have been expensive with the Texas Tower being at critical path.”