Case Study: Nigg Terminal

Early 2015 saw a major milestone for Denholm MacNamee with the successful completion of de-sludging and water-jetting operations on a large diameter crude oil storage tank to allow inspection and re-certification to take place.

Located at the Nigg Oil Terminal, this work was undertaken during the challenging winter months and, on completion, was the largest diameter (108m) tank clean ever undertaken by the company to date.

Process

In the initial stages of discussions with the client, Denholm MacNamee recommended the use of its non-intrusive tank sweeping system. This allows both the agitation and mixing of the tank contents without manned entry and, once mixed, the contents of the tank can either be transferred to another tank for treatment at a later date or "side-streamed" to a centrifuge system for the on-site processing of solids and recovery of hydrocarbons.

After discussions with the client, it was determined that due to limited recoverable hydrocarbons being present,  in this instance an "intrusive" clean using both mechanical dozer systems and manpower would be their preferred method.

Utilising a pair of mini hydraulic dozer systems and a team of highly experienced Denholm MacNamee personnel, work began to clean and water-jet the tank internals to achieve the desired inspection standards required by the client’s third-party inspection company.

Result

48 days, 29,500 man hours and no LTIs later, the tank was handed back to the client in the required condition.

Conclusion

The client’s spokesman commented: "This was a good job, safely delivered and well executed, given the task and conditions."  He added that they "would have no hesitation in recommending Denholm MacNamee for similar projects."