- Tube Tech surveyed the flare line and the client provided digital images, isometrics and inspection records.
- Surprising the client Tube Tech reported that the flare line could be cleaned online.
- If it could be achieved, while addressing all safety issues, it would be a world first for the oil industry.
- The flare line clean could then be taken out of the shutdown and be done at the client's convenience.
- Tube Tech demonstrated their technology on a full-scale mock-up of key sections of the flare line at its UK operations centre.
- The client's consultants witnessed a successful on-line trial, which demonstrated multiple fail-safes.
- A bespoke seal coped with temperatures and pressures inside the flare line and prevented oxygen and spark ingress and the escape of toxic gases.
- The major technical difficulty was to design seals to access 25mm valve ports located at intervals along the length of the flare line.
- Ultimately, only two points of entry were used.
- Cleaning was carried out using pulsed high-pressure jetting lances designed to be heat and scratch resistant when fed into the small 25mm entry points.
- All three systems devised for the project were trialed on the life-sized mock-up.
- Locating the deposits and establishing their level and density before cleaning was carried out by Tracerco, using gamma ray-based inspection before, during and after cleaning.
- Intrinsically-safe video probes were used by Tube Tech through the 25mm ports to take digital images before and after cleaning.
- The objective was to reduce the deposition level within the flare line by removing as much sludge as possible, to level the remaining deposit and achieve an 80% cleanliness level in order to reduce excessive back-pressure.
- Some entry points turned out to be corroded shut or obstructed by weld intrusion, but Tube Tech's 'design-on-the-run' reputation came to bear and equipment was modified to accommodate this unforeseen additional challenge.
- In just five days the cleaning standard had been achieved.