30 20 25 10 15 40 35 50 45
45
42.5
35
25
5
and molybdenum content, making Sanicro 35 an excellent material for many petrochemical applications. Combined with excellent pitting corrosion resistance, it is also suitable for environments with organic acids contaminated by halides such as chlorides and bromides. For refineries and renewable fuels Sanicro 35 has great resistance to ammonium chloride corrosion, and in laboratory testing, it has shown similar performance to Alloy 625. This makes it a good option for overhead condensers in refineries. In hydrotreater plant heat exchangers, stabilised 304 grades TP321 and TP347 can suffer corrosion and cracking due to long-term build-up of ammonium chloride deposits. The standard solution has been to upgrade the tubes to Alloy 625, but Sanicro 35 can offer a cost-effective alternative to the nickel base alloy. Hydrotreater plants processing renewable feedstock use Alloy 625 extensively due to ammonium chloride deposits or high- temperature, acidic water phases containing chlorides. Advanced laboratory tests have shown that Sanicro 35 is resistant to these kinds of environments and, therefore, offers a cost-efficient alternative to Alloy 625. For hydrotreater reactor effluent air coolers (REACs), ammonium bisulphide corrosion is commonly the main concern. However, in some cases, the process stream can also contain high amounts of chlorides. In such cases, Sanicro 35 offers a cost-effective alternative to the standard solution of using Alloy 625. The grade’s high chromium and molybdenum content makes it resistant to high TAN feedstocks. It is, therefore, also suitable for several waste-to-hydrocarbon processes, and has, in Sanicro 35 has shown high corrosion resistance in caustic environments
Sanicro® 35 Alloy 625 Alloy C-276 254 SMO® 0
several pilot and demo plants, outperformed Alloy 625 and other nickel base alloys. Offshore, marine, and seawater applications Sanicro 35 has excellent resistance towards offshore marine environments and sour service. It is, therefore, considered a good alternative to Alloy 625 when sour service resistance is required in H&I systems. Thanks to its fully austenitic microstructure, it is not susceptible to hydrogen-induced stress cracking (HISC). The grade is, therefore, considered a good alternative to precipitation hardened nickel base fasteners in offshore environments. In service and advanced laboratory testing, it has shown excellent resistance towards chlorinated seawater. The grade is, therefore, a good material for seawater-cooled heat exchangers. Moving industry forward Sanicro 35 bridges the properties gap between super austenitic steel grades and more expensive high nickel alloys for the chemical, petrochemical, and refinery industries sectors. Its excellent corrosion resistance and mechanical properties make it an interesting and cost-saving alternative for many applications where nickel base alloys are the traditional material solutions. 1 PREN = %Cr+3.3×(%Mo+0.5×%W)+16×%N Sanicro is a trademark of Alleima. Angela Philipp and Jonas Höwing Alleima Contact: angela.philipp@alleima.com, jonas.howing@alleima.com Figure 3 Results from crevice corrosion testing of Sanicro 35 and competing alloys according to ASTM G48 Method F
www.decarbonisationtechnology.com
67
Powered by FlippingBook