Heat Exchanger Severe Scaling Removed from U-Tubes

Throughput improves following in-situ heat exchanger cleaning

The ‘A’ platform, operating in the oil field off the coast of Qatar, was experiencing problems because of severe blockages inside two shell and tube crude oil heat exchangers particularly in the U-bend section. The severe scaling was affecting rig processes – and the quality of the crude oil exported from the platform.

The Challenge

  • The scaling and blockages were restricting the amount of heat put into the crude oil which helps reduce the water content.
  • The less water in the oil, the better the crude quality.
  • The right temperature also reduces the viscosity of the oil and improves platform efficiency by being able to process and pump the oil faster.
  • Previous cleaning efforts by other contractors using conventional and even some quite-advanced methods had failed to clear either the straight legs or U sections.

Solution

  • As with all offshore contracts effective preparation was paramount and with two different levels of fouling to deal with Tube Tech arrived on the platform with a selection of innovative cleaning technology plus technicians to work both day and night shifts.
  • Tube Tech lined the entire bund area, the location of the units, with plastic and a waste collection divert was also erected in the bund area.
  • Crude oil heater ‘A’ was cleaned first as it had the least fouling and needed to have an IRIS inspection immediately after cleaning. Super high pressure water jetting using a combination of turbojet & polishing jets was used to clean heater ‘A’ quickly, after cleaning the IRIS inspection was achieved successfully.
  • Crude oil heater ‘B’ was initially cleaned using the same system as ‘A’ unit, once all the blockages were removed (100% of the tubes) a thin hard scale was left even harder than originally thought, Tube Tech converted their bespoke pumps to facilitate considerably higher pressures, attached their rotating wysper seal lance and were then able to again achieve the desired standard suitable for IRIS inspection to prove that the tubes were still in a good physical order and suitable working condition.

Tube Tech Comment

Scott Donson, Technical Sales Manager: “Logistically and technically this was a big and quite complex operation because we had to overcome several obstacles, not least limited access combined with removing extremely hard deposits from hairpin bends/ u tubes, on an oil rig in the middle of the ocean. The variety of equipment shipped to the Gulf assured us the greatest possible chance of success and was far more than other contractors had taken previously. We thoroughly tested our new technologies and equipment prior to shipping on mock tubes with blockages to the same dimensions as the clients crude heater to be certain our unique nozzle designs would negotiate the tightest of bends. Once our system was installed and we had demonstrated our ability to extract the tenacious blockages hiding around the u tubes, the client allowed us the time to achieve best overall cleanliness which was to ultimately benefit our client long term. Patience and dexterity of technology was the key on this occasion. Its lovely to see the upfront planning and hard work back at base paying off culminating in a successful operation and a really happy client.”

Clients Comment

The client’s Senior Process Engineer said: “Tube Tech had been patiently waiting in the wings while we tried other high-tech and traditional options, both locally and globally, with limited success. The time came to try Tube Tech, a company which is reputed to be a technical leader in their field by the likes of Shell, BP and Total. I confess to being pleasantly surprised when we witnessed not only the level of success the Tube Tech team achieved where others had failed but their professionalism, dedication and team work, not just from site personnel but from their HQ in England. Tube Tech were the only company we found that was willing to develop a brand new, dedicated solution to our problem with several back-ups in tow. In my opinion they definitely live up to their reputation as a world leader in their field of hi tech cleaning. The savings our Company has made have been substantial and therefore I have absolutely no hesitation in recommending this company to others.”

Images and videos associated with this project are available via Tube Tech International
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