Condition Assessment Strategies in Centrifugally Cast HP Steam Reformer Tube Alloys
In steam methane reforming one of the key reliability aspects relates to ensuring the integrity and reliable operation of the catalyst filled radiant tubes. The tubes experience temperatures beyond 900°C for a considerable length of time, which makes creep the prime mode of failure. Predicting and assessing creep damage rates is challenging for a number of reasons: the alloys are not subject to any international specifications, the tubes are cast and their microstructures evolve substantially in service. These factors are known to lead to considerable scatter in creep life, strain and ductility response.
This paper describes the initial steps of a current approach to managing tube life and outlines the early stages of a study aimed at development of a methodology to utilise appropriate inspection in combination with judicious creep strain/rupture testing to provide an effective strategy for longterm assessment and management of reformer tube integrity. The work involves creep testing and microstructural characterisation of service-exposed material to incorporate the influences of material changes.