Corrosion of Stainless Steels of Cryogenic Hydrocarbon Flare Tips Burners

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.