Outokumpu delivered duplex stainless steel for biogas tanks built by German biogas tank manufacturer Börger GmbH. Tanks built in LDX 2404® and LDX 2101® are now up and running. Lean duplex stainless steel is proving to be an ideal construction material for new generation biogas tanks. These biogas tanks built by Börger are larger biogas tanks than they had built before.
Biogas tanks are usually built from cement or enamelled, zinc-coated or coated carbon steel. Börger builds their biogas tanks in stainless steel, because they see the stainless steel as the best defence against corrosive conditions in tanks, caused by hydrogen sulphide. Initial idea was to build the biogas tanks in austenitic stainless steel. When Börger approached Outokumpu, a new duplex stainless steel grade LDX 2404®, the sixth and latest member of the Outokumpu duplex family, had just been launched.
Tank weight reduced by 25%
Outokumpu's sales company in Germany saw the potential of LDX 2404® for biogas tanks.
Mr Bernd Beckers Global Product Manager Duplex at Outokumpu said that "LDX 2404® is a grade that provides all the benefits of lean duplex stainless steel. It is high-strength achieved with low nickel content, and it is highly corrosion resistant properties exceed for example the austenitic 316 grade. Moreover, duplex LDX 2404® features excellent mechanical properties."
Börger opted to use Börger opted to use LDX 2404® in storage tanks and a combination of LDX 2404® and LDX 2101®, lower-alloy duplex stainless steel by Outokumpu, in process tanks. Due to duplex stainless steel, tank construction weigh less compared to the conventional stainless steel grades. Low nickel content of lean duplex translated into price stability against the volatile nickel price.
Mr Gerd Buβ sales manager at Börger GmbH said that "The main reason for the selection of lean duplex LDX 2404® for the tank system was its high strength which allowed us to use 25% less material. Additionally, for the first time we could create a storage tank with a capacity greater than 5 000 cubic meters. Stainless steel tanks are maintenance free and maintain their value and additionally their size and design can be flexibly adapted to meet the needs of our customers."
Duplex biogas tanks manufactured by Börger are now up and running in West-Münsterland, Germany. Börger's biogas tanks are bolted, which allow individual and flexible design, and thus possibility to choose between different lid types. It even allows dismantling and re-assembling the tank at a different location. After 2020, when current regulations for the renewable energy policy will expire, the tanks could be used for different purposes if necessary.