Careers Texas Tower (VCFE) Mechanical External Shell Side Fouling Removal is a World First
Two Texas Towers (VCFE Platformer) Restored in Five Shifts, Down from 24 Shifts.
Safety, speed, and cleanliness were deemed the most important factors by the 230,00bpd (crude) and 17,000bpd (lubricant) French refinery. The two combine feed/effluent exchangers were last removed of fouling on the shell and tube side in 2001 when it took 24 shifts to restore each VCFE Texas Tower, using traditional high-pressure water jetting guns and lances, but this was deemed dangerous, slow and very inefficient with very little improvement in performance.
ROT / HIT (Reactor Outlet Temperature – V – Heater Inlet Temperatures)
- Cold Approach Graph
- Cleaning Hot Approach Graph
- Heat Transfer Coefficient Graph
The Challenge
- Heat transfer in both Texas Towers had been on the decline since 2001 and to complicate matters, there was no record of deposit characteristics.
- With vast VCFE heat transfer restoration experience, Tube Tech knew that gummy and coke-like deposits settle in certain areas of the exchanger.
- Accidental carry over of several cubic metres of light oil compounded shell side fouling of both Texas Towers. This light oil was suspected to have burnt off at high temperature leaving a hard layer of hydrocarbons of unknown thickness, volume, consistency or location.
- When previous attempts in 2001 on a cleaner exchanger had limited success it was obvious that neither traditional 1000 bar jetting nor chemical cleaning would remove a likely hydrocarbon coke formation deep in between the tubes of the shell.
- The client was very concerned having tried several chemical and water jetting contractors around the world but none guaranteed success due to the limited access.
- With a critical shut down schedule, the client was eager to have both the shell side and tube side of both vertical combined feed/effluent exchangers cleaned within a 6-day window instead of the previous 24, and at the same time remove the coke.
The Solution
- Both exchangers were pulled and suspended vertically in parallel to their respective shells.
- Both Texas Towers were restored with Tube Tech’s own innovation called Shell Jett.
- The combined effect of this highly unique jetting process was faster than anyone had predicted.
- Tube Tech used its darTT technology to remove blockages from 3612 tubes.
- Each darTT was handmade to fit the 14.83mm tube ID and debris from within the tubes was collected beneath the two Texas Towers.