New market for finned tubes

Sandvik Steel has developed a production method for internally, longitudinally finned, cold finished tubes for use as pyrolysis tubing in the demanding environment of ethylene furnaces.

With supply approvals having been obtained from key contractors, Sandvik has become an approved industry supplier. As a result, a major order has been obtained from Russia's largest oil company, Luk Oil Europe Holding Ltd, for the supply of furnace radiant tubes for four furnaces at the Luk Oil ethylene plant in Burgas, Bulgaria.

In the ethylene process, steam and hydrocarbon are mixed together and heated, resulting in a tube metal temperature of between 900° and 1150°C and extremely aggressive and corrosion conditions. In order to extend the life of tubes in such an environment, Sandvik produces the required 2-3" (50-76 mm) outside diameter finned tubes in a modified high temperature steel grade Sandvik 353MA (UNS S35315) - an austenitic, chromium-nickel steel alloyed with nitrogen and rare earth metals.

Longitudinal fins increase the inside surface area of a tube by up to 25% and this enlargement of the tube's inside area improves heat transfer, which means increased productivity for ethylene producers.