Corrosion of Stainless Steels of Cryogenic Hydrocarbon Flare Tips (Burners)
Keywords:
corrosion, cryogenic service, environment, scaling, stabilization, stainless steel.Abstract
Analysis of the corrosion resistance of AISI Type 304 Stainless Steel (SS) used
in flare tips (burners) of natural gas (NG) extraction facilities is considered to determine the
resistance of this grade of austenitic stainless steel to the aggressive corrosive actions of the
environment. It was observed that the grade of SS yielded quite early to corrosion attacks
which gave effects to scaling, flaking, pitting, material thinning and flare distortions in the
burners contrary to expectations. This necessitated replacements with costs and thus there
was need to analyse the causes and find solutions to the problem in such a way that a longer
service time could be obtained with minimal shut downs. The solution was found in the
grades of SS with balanced higher quantities of nickel, chromium, molybdenum and SS
type with partial nitrogen substitution for nickel which helps in stabilization of the austenite
structure. There was need to balance the contents of the alloying elements to ensure the
desired microstructure is preserved. Further study is required in the area of “weld decay”
caused by intergranular corrosion of the weld HAZ.
