When one of New Zealand’s leading suppliers of refined petroleum products to the New Zealand market was facing difficult and costly maintenance to an existing structure, they engaged GRIT to develop a practical solution that was fit-for-purpose, safe, and cost-effective. Through smart and lateral thinking, GRIT was able to minimise the cost and risk involved with this brownfield industrial maintenance project.
Located in the North Island, this industrial production and manufacturing plant processes a wide range of products imported from around the world and produces world-class clean fuels.
Although originally built in the early sixties, a major expansion and upgrade of the original plant in the mid-eighties resulted in a relatively modern industrial plant. The continual upgrading of plant and preventative maintenance ensures world-class reliability and efficiency.
Our client identified that one of the plant’s reactors needed its top gasket replaced and the surfaces required resurfacing. However, they knew this would not be an easy task since the top of the reactor is +/- 70m above ground level and weighs 13 tonnes.
In order to carry out this scope, the top section of the reactor had to be removed or suspended to provide access to the surfaces. Lifting the top section by crane would be very expensive and risky as bad weather such as high winds would create a schedule risk during a very tight turnaround window.
GRIT was engaged to investigate the options and provide a practical, cost-effective solution that would meet site safety requirements and reduce the risk.
GRIT’s team investigated a number of options until they came up with a practical solution – designing a lifting frame which attached to the top of the reactor support structure (70m above ground) to lift the 13-tonne vessel + 3 tonnes of machinery required to complete the maintenance.
The design of the lifting frame was tailored around constructability and a fit for purpose approach with a focus on safety. This involved an engineering assessment of the reactor support structure to consider the existing load cases plus the additional load from the frame and suspended vessel and machinery. Due to site safety constraints, all welding was completed offsite by a local company who fabricated and installed the lifting frame.
GRIT’s team also wrote a load testing, lifting, and suspending procedure, then worked with local riggers, to set up, load test the frame, and eventually lift and suspend the reactor vessel.
The vessel was lifted and supported for about a week while the maintenance was completed by the machining contractor. Since the lifting frame was installed before the turnaround, there was no schedule risk due to the weather.
Additionally, the lifting frame and procedure are reusable which means future maintenance on the reactor can be undertaken with very little cost.
- Added value – Removed turnaround schedule risk, reduced resource demand, reduced cost, and provided a useful maintenance asset for the future.
- Cared for our connections – Designed a lifting system with a completely redundant parallel rigging system where people were in the line of fire with lifting. This provided a safety net in case of any rigging equipment failure.
- Owned the challenge – The team used lateral thinking, investigating a number of options until coming up with a practical solution.
- Tailored for constructability – Designed the frame to suit site safety constraints and use the existing support structure where possible to distribute loads, minimising modifications.
- Cost savings – This design provided savings in the short term to offset the need for a large crane but also significant savings long term as the lifting frame and lifting procedure are reusable in future.