The project was undertaken on a massive 120 foot high, 100,000 barrel propane tank which is an important plant component. External corrosion to the flange bolts and body meant the six inch ball valve needed to be changed, but the traditional route would have meant decommissioning the tank. This would have disrupted production for several months at high cost, and involved complex recommissioning, as well as potentially creating process problems.

Furmanite fitted a strongback and ‘G’ clamps to secure the valve while a decision on changing it was taken, and was then selected to perform the valve change work while the tank remained live. Furmanite’s proposal to achieve this was selected after review and risk assessment of a number of possible options.

Furmanite’s solution involved a hot tapping procedure to execute the work, using a valve change out tool and plug assembly designed and manufactured by Furmanite. A trial run on a redundant tank using the valve change out tool and plug was undertaken in advance of the procedure being performed live.

Following a hot bolting procedure on the 24 inch nozzle flange and six inch ball valve lower and top flanges to ensure a quick change, a valve plug was inserted and the valve change out performed.

Furmanite technical support engineer Doug Cameron explained: “The valve change out tool (previously shown to accommodate high pressures) is designed with high density neoprene/polyurethane rubber seals, grips and gland assembly, and tests were carried out to confirm its suitability. The tool has a launching and retrieval chamber and gland assembly, and was mounted on the existing transition piece above the valve. The top grips were operated initially and the plug positioned, expanded and tested. The lower grips were then operated to allow the old valve to be removed and the new valve positioned, bolted and torqued down. The plug could then be retrieved allowing the new valve to be closed, and the plug assembly was vented and fully removed.”

The project was carefully planned and, with close co-operation with the customer, was safely and successfully completed in just eight days by Furmanite technicians, with rigging and mechanical assistance from the in-house team.

Cameron pointed out: “Furmanite is well known for being able to undertake special and difficult tasks on process and steam systems. This is typical of the service we are able to offer our customers to help them keep their assets operating and earning – proposing the solution, managing the design and testing, and performing the project successfully on site. Now that the expertise has been demonstrated, it could have wider application on cryogenic tanks elsewhere.”