Our heat exchanger tubes are typically used in
Overhead condensers are part of the distillation of crude oil, the Cooling/condensation is often made with water containing chlorides, air and other contaminants that contribute to increase of corrosiveness. Materials of choice from Alleima portfolio offer Sanicro® 28, SAF™ 2507, SAF™ 2707 HD and Sanicro® 35 that can extend the lifetime of the equipment and avoid costly maintenance stops.
To produce concentrated phosphoric acid it’s needed to have heat exchanger evaporators / coolers. This acid is very aggressive, with the presence of large amounts of contaminants (e.g. Chlorides, fluorides, etc) that will increase the corrosion challenges. Alleima can offer different grades depending on the acid concentration and the impurity levels, e.g., chlorides and fluorides present in the different parts of the plant. Materials of choice are 316L, 2RK65 (904L), Sanicro® 28 and Sanicro® 35. Both Sanicro® 28 & Sanicro® 35 are applied in phosphoric acid evaporators tubular heat exchangers, besides other applications like piping, pumps, valves, etc.
Nitric acid is a strong oxidizing acid, yet it only becomes extremely corrosive when processed in high concentrations or at high temperatures. The severe corrosive conditions are typically found in cooler/condensers, tail gas preheaters, and boiler feedwater heaters, and for these demanding applications, 2RE10 outperforms 304L, the workhorse, for nitric acid.
The bimetallic tube 2RE10 / ZR702 manages the challenge of providing zirconium-level corrosion performance at an affordable price. Duplex stainless steels are recommended for applications where the cooling water has increased chloride content as a cost-effective alternative to high alloyed austenitic stainless steels. Titanium is also used for nitric acid applications.
For years, the LNG regasification industry has experienced a challenge using direct seawater in vaporizing units. The high level of chlorides in the water, the higher ambient temperature the equipment may encounter, and the lack of effectiveness of flushing the units may lead to the severe corrosion of heat exchanger tubes.
Traditionally, the most popular material used in the manufacture of vaporizing units has been the super austenitic stainless steels such as AL6XN and 254 SMO. However, cryogenic conditions, corrosive seawater, and several kilometers of vulnerable tubes create a recipe for potentially significant productivity losses and a short material lifespan due to corrosion and leakage.
Exotic, high-nickel alloys such as Alloy 625 or Alloy C276 may improve performance but are high in cost.
Alleima Sanicro® 35 bridges the performance gap between stainless steels and higher-cost nickel alloys. They offer excellent resistance to highly corrosive conditions, making them ideally suited for LNG cryogenic seawater vaporizer tubing.
In the Petrochemical plants, petroleum products are further processed to produce other products (e.g. Plastic, oils, resins, etc), these products are usually heated, reacted at high temperatures and pressures and cooled. In some parts of the petrochemical plant the corrosiveness is quite high, and the material choice is often high-nickel alloys such as Alloy 625 or Alloy C276 may improve performance but are high in cost, Sanicro® 35 is an option with similar corrosion resistance with better lifecycle cost.
In most of the Heat exchangers, especially coolers/condensers, water has been used as a cooling agent. Due to the less availability of fresh water, the use of seawater is more common, the presence of NaCl at the range of temperatures will increase the corrosiveness. Typically, in this application, the grades applied historically have been Titanium, 254SMO, SAF™ 2507, Alloy 625 and most recently Sanciro® 35.
Urea is a product that on its transformation process several equipment's have demanding corrosion resistance materials (e.g. Carbamate condensers, High pressure tubing, etc), Alleima has developed several special grades for the Urea industry (e.g. 3R60 UG, 2RE69, Bimetallic Tubes, Safurex®).
When revamping existing hydrotreaters, or building new ones, to process renewable feedstock several heat exchangers and piping systems are usually upgraded to nickel base alloys. Also in pre-treatment units, nickel base alloys are commonly used. Alleima has cost-effective alternatives to nickel base alloys in these kinds of applications. Don’t hesitate to contact Alleima to discuss the options.
Natural and chlorinated seawater, brackish water and process waste waters are very corrosive and generally require grades like super duplex stainless SAF™ 2507 or hyper duplex stainless steel SAF™ 2707 HD. In some cases, such as wastewater treatment, the corrosivity of the water can be so high that nickel base alloys are considered. Alleima has the right alloy for all water applications, so contact us to discuss your material needs.