The busy Port of Barcelona is about to witness a major stride in liquid storage tank engineering: the largest tank terminal built to date from Outokumpu’s proprietary LDX2101^® duplex stainless steel. By replacing a conventional tank material – austenitic stainless steel ASTM 304 (EN 1.4301) – with LDX2101^®, the tank maker Emypro, S.A. throws convention aside and becomes a pioneer in the industry.

By early 2007, Emypro will construct 13 tanks for the bulk-liquid storage company Relisa, S.A. at Quay 32 of the Port of Barcelona out of 1,350 tons of LDX2101^® hot-rolled plates from Outokumpu.

The important stride in materials selection comes at a time when duplex grades emerge as noteworthy challengers to standard austenitic stainless steels thanks to their exquisite mechanical properties and good corrosion resistance. These qualities of duplex translate into significant savings. “Duplex grades are noteworthy alternatives in 90 percent of medium-size and heavy industrial applications,” says Erik Johansson of Outokumpu’s Spanish sales office, adding, “The future of stainless steel is duplex.”

Using LDX2101^®, Emypro needs 200 tons less material compared with 304, because the 90 percent higher mechanical strength of LDX 2101® allows for considerably thinner plates. Savings in material costs alone amount to over half a million euros.

The tank maker took the pioneering decision for LDX2101^® with confidence, based on both the company’s expertise in storage tank engineering and trust in its stainless steel supplier’s grade expertise.

Emypro is a stainless steel tank specialist with 25 years of experience and a reference list that represents more than three million cubic meters of storage space in Europe and the Americas. Emypro’s cooperation with Outokumpu goes back 15 years and embraces many milestones achieved together, including the largest tank ever built out of duplex 2304 – 22 meters in diameter and 25 meters high. Emypro’s decision in 2005 to go for 2304 was based on the efforts of Outokumpu’s team of application and grade professionals in Spain to persuade Emypro of the merits of duplex stainless steel. Emypro could reduce tank weight by 40 tons and achieved significant cost savings as a result.

Realizing the winning potential of duplex for the new project for Relisa, Emypro’s engineers needed only 24 hours to make the decision in favor of LDX2101^® when the project got green light in April 2006. 

Relisa’s new tanks are meant for storing honey, oils and other mild liquids, ideally handled by LDX2101^®. Duplex 2304 is the appropriate grade as an alternative for ASTM 316L (EN 1.4404) for storing corrosive liquids. Duplex stainless steels perform well in the temperature range of -40…+250 degrees Celsius.

Outokumpu has developed a calculation tool to demonstrate the weight saving potential of duplex stainless steel in large storage tanks.

Layout of Relisa’s new tank terminal