Refinery Flare Structure Maintenance and Repairs

Client - Refining NZ Date - 2018

Without a properly functioning flare system, Refining NZ’s Marsden Point refinery cannot legally or safely operate. Used to vent pressure and gas during process upsets and emergencies, the flare is part of the most critical process safety system on site. Access to the full flare structure can only be gained when the refinery is shut down, once every 12-15 years.

In 2018, maintenance and repairs to the flare had to be completed within the eight day shutdown period, ensuring the flare was fit for service for the next operational period.

In order to develop a maintenance scope, a condition assessment and design review were required.

Grit Engineering worked with rope access inspectors and drone operators to safely generate detailed inspection reports including the difficult access areas.

Grit Engineers provided the scope, technical direction, review and approval for a structural assessment that was carried out using current codes and IPENZ PN19 (allowing for age of structure). The assessment considered:

  • Fitness for service of design, compared with current codes, to establish whether the
    structure needed any structural modifications or upgrades ignoring condition.
  • Fitness for purpose in current deteriorated condition, to establish the repairs necessary
    for the structure to remain in service.
  • Corrosion rates and predicted losses over the next 15 year period using NZ guidelines and atmospheric data.
  • Fitness for purpose of future deteriorated state to ensure the structure will be fit for purpose throughout the next operational period (15 years).

Minimum maintenance scopes required for safe operation over the next 12-15 years, a scope of suggested repairs to minimise future issues, along with repair specifications were generated between project execution team, RNZ stakeholders and Grit engineers.

GRIT provided ongoing support and expert advice throughout the project, inspected repairs and reviewed and approved quality control documentation.

We were also  engaged to produce a presentation on the project, detailing ongoing risks and future challenges relating to the structure after maintenance had been executed.

The client now has an idea of what they can expect in terms of maintenance in 12-15 years, along with any residual risks in between.

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