Duplex stainless steels in petrochemical heat exchanger applications

Citation

(1998), "Duplex stainless steels in petrochemical heat exchanger applications", Anti-Corrosion Methods and Materials, Vol. 45 No. 3. https://doi.org/10.1108/acmm.1998.12845cab.031

Duplex stainless steels in petrochemical heat exchanger applications

Duplex stainless steels in petrochemical heat exchanger applications

Keywords Petrochemical industry, Publication, Sandvik, Steel

A new technical brochure from Sandvik Steel describes the role of duplex stainless steels in petrochemical heat exchanger applications.

Aimed at designers, specifiers and engineers in the petrochemical and fabrication industries, the new 20-page brochure promotes duplex steels and explains Sandvik's view that, more than solving ongoing plant maintenance problems, the materials of fabrication constitute an integral part of the process technology.

The brochure describes the use of duplex stainless steels in heat exchangers in the production of organic acids, where equal or better resistance to general corrosion than high cost nickel-base alloys has been demonstrated. It also details the role of duplex steels in the chlorination of hydrocarbons and their use for cooling water applications, particularly sea water cooling.

For each of these three end uses, the brochure examines typical processes and the shortcomings of the most commonly used materials of construction. It then suggests the role for duplex stainless steels. Each suggestion is supported by a description of an actual Sandvik installation.

Duplex stainless steel can be used in many corrosive environments within the temperature range of ­50° to 300°C. When considering which duplex stainless steel to use in a particular heat exchanger, one of the main concerns is resistance of the material to localised pitting corrosion. Detailed criteria for selecting Sandvik's duplex steels is provided in the brochure. Critical pitting temperature curves for different chemical solutions are shown. In addition, there are graphs showing stress corrosion cracking and general corrosion properties for Sandvik's duplex stainless steels compared with standard austenitic stainless steels.

The brochure also contains a section on the corrosivity of organic acids, with particular focus on the most common in today's chemical industry ­ formic, acetic, propionic and butyric acids. Graphs of corrosion rates are shown for various alloy steels demonstrating the potential benefits of duplex stainless steels in heat exchanger applications.

Sandvik claims that two of the most potent tools in selecting materials for the upgrading of heat exchangers are previous experience with the material and what material solutions have been used successfully before. From this viewpoint, the brochure contains over 30 references, which present data from plants worldwide, where duplex alloys have a proven track record over a period of time.

Copies of the new brochure can be obtained from Sandvik Steel UK, Manor Way, Halesowen, West Midlands B62 8QZ, UK. Tel: +44 (0) 121 504 5100; Fax: +44 (0) 121 504 5151.