Hydrogen explosion incident mitigation in steam reforming units through enhanced inspection and forecasting corrosion tools implementation

• Published in: Journal of loss prevention in the process industries 2020-01, Vol.63, p.104016, Article 104016
• Main Authors: Defteraios, N., Kyranoudis, C., Nivolianitou, Z., Aneziris, O.
• Format: Article
• Language: English
• Subjects: Condition monitoring locations; Corrosion loops; Corrosion prediction; Gas steam reforming units; Multivariable prediction functions; Multivariable regression; Risk based inspection; Wall thickness measurements
• ISSN: 0950-4230
• DOI: 10.1016/j.jlp.2019.104016

Hydrogen (H2) explosion effects recently examined, are confirming the devastating loss scenarios to humans, environment, assets, and associated business interruption. H2 production is a core process in refineries used in further process steps. Steam reforming of natural gas or a mix with naphtha or LPG is a common hydrogen production technique, where the latest technologies have adopted enhanced metallurgies to minimize explosion risk and the associated maintenance cost following plant degradation owing to corrosion effects. However, corrosion rates are still high in specific areas of piping and process equipment. The aim of this paper is to present a methodology based on semi-quantitative RBI modeling according to regulations by API and recent EN standards, adopting a family of linear regression forecasting models that depict the yearly corrosion rate (per corrosion loop) of a hydrogen production steam reforming unit; this is done under different operating conditions (e.g., temperature, pressure, and fluid speed), metallurgy and other related physicochemical variables. The model is based on the examination of both ultrasonic wall thinning measurements and the examination of quantitative crosslinking total corrosion effects along with the physicochemical properties prevailing in different plant corrosion loops. The outcome of the regression analysis is an expansive family of multivariable equations describing, with a defined accuracy, the yearly corrosion rate and associated lifespan forecast per corrosion loop, and per examined part. These equations were further utilized in a custom-made database that can be used as an additional loss prevention tool by the hydrogen production unit management team. Evaluation results regarding the tool efficiency are presented in the following of this paper. •A family of multivariable functions was developed for prediction of measurable corrosion yearly rate and associated remaining life.•A multivariable regression methodology has been adopted.•Methodology application provides comprehensive identification of failures involving hydrogen explosions.•The outcome assists inspection and maintenance optimization in  refinery high-risk units.•Optimized inspection and maintenance without compromising safety, lead to lower operational costs.