Industry Experience Fabricating Hydroprocessing Reactors Using 2¼ Cr-1 Mo-V Steel

Starting in the 1980’s, the process conditions for hydroprocessing reactors became increasingly more severe and started to exceed the economic and technically-feasible ranges for 2¼Cr-1Mo steel. Hence, new grades of reactor steels were developed to meet these demands. Reactor fabricators, steel producers, the Materials Properties Council and some refiners cautiously developed their initial applications of the new materials, with extensive testing of both the materials and fabrication methods, and restrictions to use only the most experienced, highly technical fabrication shops. The data and experience has grown exponentially since then and today, the most commonly-specified material for thick wall reactors is 2¼Cr-1Mo-¼V steel. The list of qualified fabricators worldwide has also grown, but is still limited. The purpose of this paper is to show how the industry has climbed the “learning curve,” by giving the statistics on the overall numbers of fabricated reactors (which is now over 1150), and the locations of the fabricators by country, that have been produced. Trends on the use of forgings versus plates are also included, along with the major changes over the years in the applicable ASME Codes and API standards affecting these reactors. Some of the lessons learned from past fabrication problems are also discussed along with the subsequent safeguards initiated within the industry standards.