Pressure vessels and piping fabrication specialist and construction fabrication consortium the Hydra Arc group of companies is continuing its long-term partnership with energy and chemicals company Sasol by assisting it with the construction of an air separation unit, as well as developing outside battery limit modules for Sasol's Coal Tar Filtration East (CTFE) project.

Hydra Arc COO Sheldon Nel highlights that the company has been working with Sasol for more than 25 years, providing maintenance, turnaround, general overhaul, scheduled shutdown and project-specific services as required.

Hydra Arc was contracted by construction entities Group 5 (G5) and Stefanutti Stocks’ oil and gas divisions in January and February respectively to assist in building Sasol’s 5 000 t/d air separation train for the project’s main contractor, multinational gas and services supplier Air Liquide. The company will own and operate the train, which will supply oxygen and nitrogen to Sasol’s proprietary synthetic fuels and chemicals manufacturing process. This is the seventeenth train to be built at Sasol’s Secunda complex, in Mpumalanga.

Hydra Arc was contracted by G5 – which completed its project in June – for the fabrication of pipe spools for a cooling water line for the oxygen train. Stefanutti Stocks requires work on piping and ducting for the new train and is expected to conclude its project by February 2017.

Nel states that the G5 project required that pipe spools of about 3 300'' in diameter be manufactured, while Stefanutti Stocks requires pipe spools of 1 600''. The products are all manufactured at Hydra Arc’s Sky Hill Heavy Engineering facility, in Secunda.

In addition, Hydra Arc has been contracted to assist with Sasol’s CTFE project, which involves the extension of its Secunda plant. The plant’s extension is expected to reach beneficial operation in the first half of 2017.

Hydra Arc engineering manager Ewan Huisamen says the Hydra Arc group has earned a reputation as a fabricator of high-quality novel plant modules for the petrochemicals industries.

He notes that this particular project involves a novel approach to plant design and construction, as it comprises an intricate network of piping and cable racks, divided into subsequent modules that form part of the CTFE plant.

“The whole plant will comprise interconnected modules, which increases the amount of factory-based fabrication and reduces on-site construction time. The idea is that each module is fabricated to include all its equipment, vessels, piping, instrumentation and supporting structures,” says Huisamen.

He explains that, once the site foundations have been prepared, the modules are delivered to site and coupled to form a functional plant. Site works and modular fabrication can be run in parallel, facilitating the speedy completion of a project, as well as subsequent cost benefits.

Once completed, some modules will have a mass of more than 400 t and include two pressure vessels and all the interconnecting piping, flanges and support structures. The CTFE plant currently being built consists of 24 individual modules that have been fabricated at Hydra Arc’s Sky Hill facility.

The facility has bays that are exclusively reserved for new fabrication projects of small to very large-scale components in any material type, whether pressure vessels (drums, columns and wall vessels); heat exchangers (fixed/floating tube sheets, channel/bonnet types); larger-bore piping prefabrication; or supported flat-bottom-type storage tanks.

Huisamen comments that these modules are becoming increasingly popular globally, especially in harsh environments and complex building environments such as Canada and Russia.