Valero Turnaround & Inspection: Chemical Cleaning Tank and Containment Bund Facility Design & Construction

The Objective

When Valero Energy’s Pembroke Refinery undertook a £50m Cracking and Olefins Major Maintenance event, a key aspect of the ‘Turnaround and Inspection’ was the cleaning and maintenance of their Alkylation plant.

The presence of highly toxic and aggressive high octane gasoline chemicals in the Alkylation unit are highly hazardous and as such a rigorous cleaning regime is required prior to any maintenance of the plant.

Previous approaches to maintenance had proven expensive with key equipment being taken out of service for a prolonged period. Instead Austwel were asked to design and construct the concrete base for a temporary tank and the containment bund required around the tank in case of any tank breach.

The Solution

The client needed a cost effective solution that would provide the required support to the tank but which could be removed relatively easily when the cleaning work was completed. In addition the base would need to be designed to withstand the action of the chemicals within the tank during the cleaning process.

This construction project would require conventional civil engineering techniques as well as specialist impermeable lining installation. Survey work was undertaken to assist in the determining the size and shape of the containment bund together with the calculation of capacity required. Austwel developed a solution and produced CAD drawings for the client’s approval. A watertight seal for the tank/base intersection was created with a rebate design for the tank intersection to include a hydrophilic joint strip. The tank base was designed with fibre reinforced concrete.

The Outcome

Austwel’s proactive approach provided the client with a complete turnkey solution. Once Valero had issued the scope they were comfortable that Austwel would deliver the project on time and within budget. The tank and bund were completed to schedule and used very successfully throughout the maintenance event. The bund area with its robust construction has also provided prolonged use as a storage area for quarantined pipework allowing a safe and controlled environment for other ongoing cleaning projects.