Session: MF-24-01 Materials and Fabrication for Refining

Paper Number: 62868

Start Time: Thursday, July 15, 2021, 05:00 PM

62868 - Hydrogen Damage in Transfer Line Exchanger Tubes 

This paper presents the analysis of a Transfer Line Exchanger (TLE) tube, which ruptured from Hydrogen damage on the steam side.  Hydrogen damage occurs where corrosion reactions result in the production of atomic hydrogen.  Atomic hydrogen combines at grain boundaries or inclusions in the steel to produce molecular hydrogen.  Hydrogen may also react with iron carbides (Fe3C) in the metal to produce methane (CH4).  As a result, intergranular microfissures will form, linking to form larger microcracks and leading to eventual through-wall failure.  Decarburization will also occur near the tube surface.

 

TLEs are vertical heat exchangers designed to operate at extreme temperatures.  Pyrolysis furnace effluent gases enter the inner tubes at over 1500F.  The heat is then removed by boiler water, which is supplied to concentric outer tubes.  The boiler water generates steam that continues to remove the heat.  It is common for water side damage in TLEs to occur at the tubesheet, where solids from boiler water are known to deposit and inhibit heat transfer.  The nature of the rupture under discussion in this paper differs, because the location of the rupture was not near the tubesheet.  Metallurgical analysis confirmed indications that the tube failure is attributed to Hydrogen damage.

Presenting Author: Mary Catherine Huff Shell Downstream Manufacturing

Authors:

Amy Adams Shell Downstream Manufacturing
Mary Catherine Huff Shell Downstream Manufacturing
Jorge Penso Shell Global Solutions (US) Inc.