Abstract
An immature failure of a gas flare tip used in Qatar oil and gas offshore industry was investigated throughout this study. The design lifetime of the flare was fifteen years; however, it manifested immature failure resulting in a reduction of its lifetime to ten years. The flare is composed of different parts where the upper flare body and wind deflector showed failure while other components were still healthy. The material used for the aforementioned failed parts was Incoloy 800H, which is a highly corrosion and high-temperature resistant steel alloy. The material was rolled up and welded together with different welding joints. The root cause of failure was identified by using chemical analysis and microstructural and mechanical characterizations. For the mechanical characterization, an optical microscope (OM) and scanning electron microscope (SEM) equipped with energy dispersive spectroscopy (EDS) analyses were used for the specimen extracted from the failed part in order to ensure that the material mentioned by the manufacturer demonstrated the same metallurgical properties. For the mechanical characterization, two sets of specimens were used, one close to the failure region and the other far from the failure area. The chemical analysis revealed that the material was truthfully Incoloy 800H. The mechanical examination results showed a significant reduction of mechanical properties, i.e., the ultimate tensile strength (UTS) and microhardness dropped by 44% and 41% for samples close and far from the failure regions, respectively. Careful examination of the failed parts indicated that failure mostly took place in the vicinity of the welds, in particular near the joints. Improper joint designs, as well as a number of joints being designed in tiny areas, worsened the harmful effect of the heat-affected zone (HAZ), resulting in crack nucleation in the HAZ regions. The effect of welding in a combination of harsh service conditions of flare caused further crack extension where they merged, resulting in final immature failure.
Highlights
The oil and gas industry is accompanied by the generation of a significant amount of gas emissions and high temperatures
This paper examines the failure of the flare tip, which is generally made from stainless steel or Incoloy 800H
The existence of sour gases, hydrocarbon gases and carbon dioxide arisen from the combustion processes along with the high service temperature approximately between 500 ◦ C and 900 ◦ C resulted in surface oxidation and carburization of the flare tip
Summary
The oil and gas industry is accompanied by the generation of a significant amount of gas emissions and high temperatures. In a study done by Yousefi et al [23], the root failure of a gas flare used in the Iranian oil and gas industry was investigated According to their results, the existence of sour gases, hydrocarbon gases and carbon dioxide arisen from the combustion processes along with the high service temperature approximately between 500 ◦ C and 900 ◦ C resulted in surface oxidation and carburization of the flare tip. H2 S at 60 ◦ C and 40 MPa pressure while the external surface exposed to winds, salt spray and sand storm They stated that fatigue crack initiations were the root cause of failure resulting from the curvature design of the bellows itself, i.e., stress concentration, the high chloride content of the bellows surface, high service temperature along with the alternating vibration, i.e., fatigue. It demonstrated immature failure, a maximum lifetime of 10 years
Sign-in/Register to view highlights & summary Sign-in/Register to access full text options 
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a callDisclaimer: All third-party content on this website/platform is and will remain the property of their respective owners and is provided on "as is" basis without any warranties, express or implied. Use of third-party content does not indicate any affiliation, sponsorship with or endorsement by them. Any references to third-party content is to identify the corresponding services and shall be considered fair use under The CopyrightLaw.
