Unparalleled innovative alloys for demanding applications
^ Sandvik has an extensive manufacturing program for seamless heat exchanger tubes.
Article by Ellie Pritchard and John Butterfield
Part of the Sandvik Group, Sandvik Materials Technology is a world leader when it comes to innovating, developing, and manufacturing advanced stainless steels and special alloys for very demanding environments, and systems for industrial applications. Its business history dates back 150 years, attributing to an unparalleled level of experience and expertise. Today, the company has a strong industry position across a multitude of end-user markets with leading players.
To understand more about the company’s continually expanding material solutions for heat exchanger applications, Heat Exchanger World spoke with Barinder Ghai, Regional Technical Marketing Manager, EMEA, and Jari Ponsiluoma, Product Manager for Heat Exchanger and Fertilizer Tube, EMEA.
For heat exchangers, Sanicro® 35 offers a smarter choice compared to other austenitic or super-austenitic steel grades and nickel alloys.
Innovation is key, as with Safurex® and Sanicro® 35
In the urea industry, for example, carbamate corrosion poses a particular challenge as the fertilizer process produces ammonium carbamate, which often causes extensive and relatively rapid corrosion even among many different grades of stainless steel. To combat this, Sandvik and its long-term partner Stamicarbon developed a highly corrosion-resistant material called Safurex®. It was created by combining Sandvik’s specialist knowledge in high-alloyed stainless steel and Stamicarbon’s expertise in the fundamentals of carbamate corrosion. Safurex® has not only proved to be highly corrosive resistant, solving 80% of all corrosion issues in instances of its application, it also allows a significant reduction of passivation air (80% proven), and can be operated without oxygen (although at an increased passivation corrosion rate). Safurex® does not corrode actively, also without oxygen, and has effectively led to 1.5 million years of heat exchanger tube usage without rupture, a gargantuan achievement. Other additional benefits to plant operators are that Safurex® has higher process safety, provides a higher yield for the plant since there is less inert gas in the process, leads to less maintenance and inspection costs, has higher flexibility in operations in blocking-in and start-ups, and is less sensitive to upset conditions.
Sandvik’s product offering for heat exchangers
Sandvik has an extensive manufacturing program for seamless heat exchanger tubes covering most types of standard austenitic, duplex (austenitic–ferritic) and high-alloy austenitic stainless steels, as well as titanium and zirconium. Produced in imperial and metric dimensions, the tubes range from 12 mm up to 40 mm outside diameters, and straight lengths up to 30 meters or as U-bends. Additionally, special sizes can be made to order.
Full control, full independence
Sandvik’s highly integrated and sustainable production
Sandvik state of the art melting AOD process.
Sandvik and heat exchangers applications
“Choosing the correct materials to enhance heat exchanger lifetimes is never an easy decision,” says Barinder Ghai, “and wrong material selection can lead to shorter lifetimes of equipment, excessive costs, increased downtime, and even health and safety issues.” It is therefore not surprising that the Sandvik Materials Technology technical marketing and sales teams pay great attention in helping their customers select optimum grades for their applications with knowledge based upon their extensive service experience, which has been gained from worldwide installations.
“The most expensive solutions on offer are also definitely not always the best solution for a company,” adds Mr. Ponsiluoma. “What is particularly important is that the selected grade needs to have sufficient corrosion resistance combined with suitable mechanical and physical properties.”
In seawater coolers, for example, choosing the correct grade is critical as seawater contains large amounts of sodium chlorides and solid particles such as silt and organic solids. In such severe environments, a grade is needed that has a high resistance against both localized corrosion and erosion–corrosion, such as SAF 2707 HDTM.
Jari Ponsiluoma, Product Manager for Heat Exchanger and Fertilizer, Tube, EMEA.
“In today’s oil refineries the process streams involve many corrosive elements that can shorten the life span of low-alloyed steels. This is because refining consists of many complex processes in which the heat exchangers operate under severe corrosion conditions.
“Most leakages occur because of corrosion in the tubing,” says Jari Ponsiluoma. As such Sandvik has created several grades to provide solutions in such situations: SAF 2205™, SAF 2507®, and SAF 2707 HDTM. These grades are used in a large variety of applications such as overhead condensers, effluent coolers, feed preheaters, water coolers, air coolers, reboilers, condensers, evaporators, strippers, as well as in salt evaporation, power generation, and gas processing.
Barinder Ghai, Regional Technical Marketing Manager, EMEA.
The road forwards
Duplex vs. carbon steel in heat exchangers
Short-term carbon steel option
Increased inspection costs
More frequent maintenance required
More frequent replacements required
Greater risk of production stoppages
Long-term stainless steel/special grade option
More reliable operations
Less frequent maintenance required
Less frequent replacements required
Lower lifecycle costs
About this Featured Story
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– FEATURED STORY BY ELLIE PRITCHARD