In 1969, the Delaware Refinery, was the first in North America to install titanium tubes as part of its effort to combat severe corrosion of the copper nickel alloys from corrosive lower Delaware River Water. where chloride concentrations normally range from 100 to 2500 ppm, but can range as high as 12,000 ppm at pH 6.5 to 9.8. Since then over 640,000 meters (2.1 million feet) of titanium tubing, mainly 19.05 mm OD x 0.9 mm wall (3/4" x .035") welded tubing, have been installed in about 140 exchangers in a wide variety of services. There has never been a
waterside corrosion failure of titanium. In some cases, tubes have outlasted the other components and have been salvaged for re-assembly in a replacement bundle. Success with tubing has led to wider use of titanium for tubesheets, baffles and tie rods, waterboxes and complete shells. The most severe combination of temperature and pressure on
the process side is in the Desulfurizer Product Condensers, which have 171°C (340°F) inlet temperatures and operate at 765 psi& Refinery records indicate that there was only one process side corrosion failure, believed to be galvanically induced hydrogen embrittlement in rich monoethanolamine (MEA) operating at 120°C (250°F). There have been a few vibration failures, both baffle and mid-span collision damage, that were corrected by changes in mechanical design. Future directions for application of titanium in refineries are expected to include more original specification of titanium, use of new more corrosion resistant or stronger alloys, lighter tube wall, welded tube to tubesheet joints, titanium waterboxes and shells, piping, tower internals, complete vessels, and other components. Process design will better utilize the unique properties of titanium, for example, by using higher velocities in heat exchangers to reduce capital cost. and improve thermal efficiency.
Keywords: Titanium, titanium alloys, heat exchangers, tubing, refining, corrosion, service experience