DTEC were contracted to make a repair to the inside of a 72” Vacuum tower transfer line which was suffering from internal corrosion and erosion to the extrados of a number of bends. We developed a bespoke automation setup to provide a multi layer weld overlay using a high nickel filler material. As part of the contract we also included for our Emergency Response Service (ERS).  The service provides automation equipment, power sources, tooling and consumables to be mobilized to site prior to the start date all at pre-turnaround agreed rates. This service ensured that we were able to react to emerging workscope as and when the vessels were opened for inspection…….

 Early during this turnaround the client found severe corrosion to the lower segment of a drum on the Alkylation unit. We were able to immediately start preparation, by working with a heat treatment provider to bake out the vessel in readiness to make this repair, which consisted of applying a 5mm Thk carbon steel weld overlay build up. During this time we had a further requirement for our ERS on the Vacuum tower, this tower required repairs numerous elevations:  we provided shell wall weld overlay to extend below an existing band, provided localized repairs to internal equipment and made full circumferential seam repairs to a shell strake transition joint which was suffering from severe in-weld corrosion.

During this ERS contract we were able to mobilize and de-mobilize as the workscope increased/decreased whilst all the time maintaining the level of equipment and consumables required to react to the demands of the turnaround.

Following this contract we executed another interesting repair at a refinery in Belgium. The process vessel was suffering from Corrosion Under Insulation (CUI). This repair comes with its own challenges, as this is an external repair to the vessel there are commonly access  restrictions and weather elements to consider.  This repair required a multilayer build up with a carbon steel consumable. We fully automated these repairs to numerous locations/elevations. One particular repair area required up to 4 layers to achieve thickness criteria.

Our final project highlight of the year was the execution of approximately 55m2 of weld overlay to a process vessel at a UK chemical plant. The consumable was a nickel based alloy. This repair required the use of multiple systems and also included the lower dished end – which was also welded using automated equipment. During this turnaround we also executed a number of emergent repairs to circumferential and vertical vessel seams, again these were repaired using Vcald® automated welding technology. 

So, overall a successful year that demonstrated the benefits to our customers that DTEC provides a full turnkey service, from isolation, inspections, equipment removal/reinstatement, corrosion repair, weld overlay and de-isolations. Please feel free to contact us to discuss any of the above repair scenarios as well as our ERS emergency service.

Steve Colclough. Director