Rapid mobilisation saves refinery $100,000’s
A German refinery had traditionally allowed six days to clean their heavily fouled inside tube Fin Fan Air Cooled Condensers (ACC), with limited success. Initially contracted to clean two units, with the possibility of a third, Tube Tech in fact completely cleaned four totally blocked condensers back to full production standard within the shutdown period.
- A number of ACC serving the coker unit had become blocked with a material that consisted of an elastic, cured polymer, similar to bathroom sealant.
- The reduced efficiency of the units was costing the refinery around US $20 000 per day.
- Traditional cleaning contractors could not unblock the tubes.
- The deposit was pliable but tough and was resistant to jetting pressures up to 750 Bar/10kpsi.
- Once cooled, the deposit hardened to a brittle, glass-like consistency.
- Each fin fan unit contained 225 x 10 metre carbon steel tubes, terminated by 328mm-deep header boxes.
- As the ACC were on the refinery’s critical path, they could only be taken down for maintenance during a scheduled shutdown.
- Each single condenser had previously taken six days to clean, so this time it was important to reduce time significantly.
- An additional hazard risk for the cleaning team was aromatic solvent left behind by a previous cleaning attempt.
- With only a week’s notice to plan the project, prepare a quotation and get all necessary equipment assembled and shipped to site, Tube Tech moved with well-practised speed.
- Tube Tech inspected the tubes to discover the extent of the fouling.
- Three alternative cleaning systems were taken to site to ensure all scenarios were covered.
- The fouling to be removed from the inside of the tubes was a gooey and putty-like substance, which included the remains of catalytic (PCA) material.
- The effluent was potentially carcinogenic and would therefore require the operators to wear half-BA suits in the cleaning area.
- Two innovative cleaning methods were used to clean both the headers and tubes effectively.
- The first method was based on the well-established SafeTrack system.
- The second method utilised a newly-developed Hydrolance, a hydraulically-driven rotary lance which employs a hydraulically-powered reaming principle with simultaneous pump pressure of 30-52kpsi water.
- The Hydrolance applied a high-torque rotary action within the tube and it removed the various consistencies of deposit encountered.
- Despite the sticky nature of the effluent, which constantly threatened to glue the jetting lances in the tubes, both systems progressed better than expected.
- The cleaning went so well, that the two ACC units Tube Tech had been contracted to clean were completed quickly enough for the client to ask for a third, then a fourth unit to be cleaned as well.
- All four units were completely cleaned to inspection standard within the shutdown.
Tube Tech Comment
Mike Watson, Technical & Managing Director:”This is an excellent example of the kind of rapid mobilisation that makes Tube Tech one of the most responsive and effective companies in the field. In this case, we mobilised to site at very short notice, as the client wanted time to review our technical approach and approve our quotation. In the most serious emergency, however, where getting to site is more important than knowing the cost in advance, we can mobilise to sites in Europe within 24 hours and within 12 in the UK itself.”
The Shutdown Manager commented: “Cleaning these important fin-fan units has always been a problem for us, both in getting them cleaned in the time available and to the required standard, using our usual local contractors. This time we had a situation where the decision to clean the units was not made until very late in the planning for the shutdown as our replacements had been delayed. As it has been taking six days to clean just one unit and we wanted to clean at least two, we knew we had to look for an alternative service provider and we found Tube Tech. Tube Tech quickly came to the refinery to assess the problem and prepared an acceptable quotation so that we were able to get them on site in just one week. The cleaning went exceptionally well – and so quickly that we were able to get them to clean not two ACCs, but four. We had been planning to order some new ones, so badly were they blocked, but Tube Tech was able to clean all four to a much higher standard than we have seen before, so we have made some really great savings. If we had known about Tube Tech before, the savings could have been even greater, as we could have avoided ordering new ACCs.”