A former refinery in Eastern Canada was carrying out a site-wide conversion in preparation for the use of renewable fuels instead of oil. The Canadian government was partly financing this conversion, and the refinery aims to start processing sustainable aviation fuel (SAF) this summer, which can result in an up to 80% reduction in carbon emissions compared to the traditional jet fuel it replaces.
Two reactors and two drums required an internal metallurgy upgrade due to the new operating conditions, as with renewables processing, reactors are susceptible to high temperature free fatty acid corrosion, sulfidation, wet chloride corrosion, and stress corrosion cracking. This upgrading could be achieved by automated welding, or high velocity thermal spray (HVTS).
The refinery, in conjunction with its EPC (Engineering,Procurement and Construction contractor) decided to use HVTS instead of automated welding, which would probably save half of their costs, and selected Integrated Global Services (IGS) as their turnkey contractor.
Another reason for not using automated welding, was that the substrate does not have to be preheated, which was important as the facility was subjected to Arctic conditions. The selected contractor could perform the blasting, provide ventilation, and apply the thermal spray, as well as supplying inspection services.
IGS designed and specified two different alloys for the drums and the reactors, NiCroMoXX type material was used for the reactors due to its excellent resistance to chloride corrosion, SCC and sulfidation, and for the drums, a NiCroMoWXX material was used because of its proven corrosion and erosion resistance.
The facility owner required comprehensive pre-qualification testing and adherence to a tight engineering standard, to govern the quality of the cladding applied and ensure that the HVTS protection would hold up against the new harsh corrosion environment.
Iain Hall, IGS CTO, said: “While material selection is important, it is only a small part of the technical package required to ensure durable long-term performance in cladding systems. Careful attention to surface preparation and accessibility, utilisation of the High Velocity process, and critical parameter control, is necessary to ensure homogenous alloy cladding with the right mechanical properties”.
IGS delivered an engineering package, including the project plan, method statement, inspection test plan, project safety analysis, risk mitigation plan and the job-specific safety data sheets, and the whole project was completed in 29 days.