Heat Exchanger World magazine April 2024 | Page 32

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Duplex can be used , including duplex or superduplex for pump and pipe connections . Finally , duplex stainless steel ’ s weight properties and low maintenance make it ideal for any load-bearing functions ( architecture , cranes , bridges ) or where a favourable strength-to-weight ratio is required . In water management , duplex ’ s combination of corrosion / erosion resistance and high strength comes into its own . An
Alleima duplex SAF™ 2205 stainless steel heat exchanger tubing , used in chemical and petrochemical plants . application of duplex highly advantage in locations that are difficult to inspect . Longer service life and reduced maintenance means less offline time and , in the case of bridges , less interruption to traffic .
Applications This is why duplex grades are finding ever more uses across a wide range of industries , including oil & gas , chemical & petrochemical , food & drink , paper & pulp , water management ( including desalination ), architecture & street furniture , and bridges . Let us examine some of these . The oil & gas , petrochemical and chemical industries remain the primary drivers for duplex stainless-steel demand . After the Covid lull , all these industries are booming . Duplex is used in subsea umbilicals in offshore installations , and several orders have recently been placed with suppliers such as Alleima and Tubacex . In a first of its kind , a gas project in Oman applied duplex type 2205 for a 24-inch pipeline that is 34km in length . The line pipe is coated and buried to ensure its external corrosion protection . Heat exchangers in chemical and petrochemical plants require duplex grades . Mayr & Wilhelm recently chose Alleima ’ s duplex SAF™ 2205 stainless steel for the tubing of its shell-and-tube heat exchanger . Superduplex , such as DMV25,7N from Mannesmann Stainless Tubes continues to be the leading material selected not only for conventional oil & gas applications but also CCUS developments . A special subtype of petrochemical is urea and ammonia production , used in fertilizers . The leading technological provider is Stamicarbon , which is building a new generation of low-energy plants , in the USA , Sub-Saharan Africa , China ’ s Jiangxi province , and other places . The high-pressure equipment for these plants is in superduplex stainless steel Safurex ® ; whilst the latest developments from Mannesman Stainless Tubes of DMV 29.7 super duplex provide solutions in seamless HX tubing and pipe . Another area in which duplex grades are required is CCS ( carbon capture & storage ) technology . This involves separating the CO 2 from other combustion gases , compressing and transporting it to the sequestration location , and inserting it into the subsurface reservoir . To withstand the acidic conditions , only the highest grades
The DESMI scrubber-grade pump . The DESMI exhaust gas cleaning systems ( EGC systems ), known as scrubbers , reduce sulphur content from exhaust gas . The pumps are made in superduplex to handle high temperatures and severe corrosion .
3D printing
Additive manufacturing or 3D printing has long been applied to nickel and titanium alloys to make aircraft parts and prosthetic devices . Now duplex is catching up , and there are clearly opportunities for components such as heat exchangers , offshore platforms , chemical processing equipment , boilers , and pressure vessels . Alleima ( formerly Sandvik ) collaborated with BEAMIT to produce superduplex impellers for use in offshore installations . The Japanese construction company Takenaka Corp . Worked with MX3D to produce a duplex structural connecter using the WAAM ( Wire Arc Additive Manufacturing ) method . In April 2022 3D Metalforge announced it had developed printing parameters for additive manufacturing in superduplex . Also , ADDere has developed laserwire additive manufacturing systems , with a laser heating and closed-loop control system , which allows for precise heat control across the entire 3D printing process .
32 Heat Exchanger World April 2024 www . heat-exchanger-world . com