Challenge your expeCtations

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If eight shutdowns could be reduced to one, what would that do for your productivity?

The challenge

a german oil refinery experienced corrosion problems in the overhead condensation unit of its crude oil distillation column. heat exchanger lifetime was short. twice every year, the process had to be shut down to replace the carbon steel tube bundle. the oil refinery’s goal was to increase the lifetime of the tube material in order to meet a standard 4-year inspection interval for the distillation column. they, therefore, called on sandvik’s metallurgical and materials processing expertise.

as pitting and under deposit corrosion were the reasons for the short heat exchanger life, sandvik recommended that the refinery should replace the carbon steel tubes with next generation duplex stainless steel grade, sandvik saF 2707 hD™. this hyper duplex steel has good resistance to chloride induced stress corrosion cracking and its minimal thermal expansion makes it easy to install into a carbon steel construction. Due to the increased corr-osion properties the wall thickness of the tubes could be reduced from 2,77 mm to 1,65 mm.

The Sandvik solution

The result

sandvik saF 2707 hD™ tubes were installed in 2006. the new tube bundle was inspected after 6 months and showed slight erosion corrosion. shutdown after 4 years showed no further erosion corrosion. after cleaning, eddy current testing and hydro testing, the bundle was reinstalled to run for another 4 years.

reducing the number of shutdowns from 8 to1 over a 4 year period has resulted in fewer steel bundle replacements, which has contributed to increased working safety. operationally, it has meant large savings in terms of material replacement, manpower and lost production.

Would you like your heat exchanger tubes to run 8 times longer between maintenance checks? By switching from carbon steel to Sandvik SAF 2707 HD® tubing in its heat exchangers, a German oil refi nery makes major savings in terms of material replacement, manpower and lost production.

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The challenge

A German oil refi nery was experiencing corrosion problems in the overhead condensation unit of its crude oil distillation column. Heat exchanger lifetime was short. Twice per year, the process had to be shut down to replace the carbon steel tube bundle.

The oil refi nery’s goal was to increase the length of the tube material’s life in order to meet the standard 4-year revision intervals for the distillation column.

The Sandvik solution

In 2006, the oil refi nery changed its tube material from carbon steel to Sandvik SAF 2707 HD®, a hyper duplex stainless steel with excellent resistance to pitting corrosion and chloride-induced stress corrosion cracking. Due to the increased corrosion properties of Sandvik SAF 2707 HD®, the wall thickness of the tubes could be reduced from 2.77 mm to 1.65 mm.

The result

The new tube bundle was inspected after 6 months, and showed slight corrosion. Shutdown after 4 years showed no further corrosion.

After cleaning, eddy current testing and hydro testing, the bundle was reinstalled to run for another 4 years.

Reducing the number of shutdowns from 8 to 1 over a 4-year period results in major savings in terms of material replacement, manpower and lost production. Fewer steel bundle replacements also increases occupational safety for the people involved.

CHALLENGE YOUR EXPECTATIONS

C278308_CaseStorie_Marathon.indd 1 2010-11-10 09.39

sandvik Mater ia ls technology – se-811 81 sandviken, sweden, phone +46 26-26 30 00, Fax +46 26-26 02 20www.smt . sandv ik .com

Case story | Heat exchanger tubes l Reducing shutdowns

sandvik Mater ia ls technology – se-811 81 sandviken, sweden, phone +46 26-26 30 00, Fax +46 26-26 02 20www.smt . sandv ik .com

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