ABSTRACT
Predicting corrosion risks and developing inspection and mitigation plans form a vital part of any Integrity Management System (IMS). Most of the emphasis from operators is given to upstream and processing facilities, however, the facilities installed downstream, in particular the storage and transport of refined hydrocarbon products, are often considered in the “fit and forget” philosophy.
Refined hydrocarbon products such as Jet A1, LPG and ULG etc. are not generally corrosive to metals and alloys which are used for their storage and transport; however, they do contain dissolved water, organic sulphides and oxygen containing compounds that can cause corrosion over time. Conventional corrosion prediction models are not relevant since hydrogen sulphide and significant carbon dioxide are not present. In order to overcome this limitation and to allow corrosion risk assessment of both existing and aging facilities, an alternative in-house corrosion risk assessment methodology has been developed. This methodology helps to dilute the corrosion risks associated with these facilities in a well-structured process as practiced for one of the major operators in the Middle East. This paper discusses the methodology adopted to model the corrosion rates and risk assessment involving both probability and consequences within these product streams.
INTRODUCTION
Refined hydrocarbons or fuels are the backbone of modern day industries whether it’s aviation, automobile, shipping, power, agriculture, fertilizer, textiles or any other sector. Crude oil which is a mixture of different liquid hydrocarbons undergoes distillation and treating operations, yielding refined hydrocarbons that include unleaded gasoline (ULG), liquified petroleum gas (LPG), Jet A1, Gasoil and JP8 (military grade aviation fuel). Since these products are refined, it is misunderstood that they cannot corrode the equipment and pipelines that handle them. Vice versa, the quality of these fuels can be compromised by the equipment they are contained in, whether metallic or non-metallic once degraded or corroded. This is one of the reasons there are sets of filters installed to maintain cleanliness of the fuels at locations along the transportation route of these products. Thus, performing corrosion risk assessments for these assets is vital for their reliability, personnel safety and the environment in which they are contained.