New grade P9Mod has been developped in order to improve resistance to coke deposit comparing to widely used P5 or P9 grades in refinery furnaces.

Specific chemical analysis based on Cr, Si, Cu and Ni contents  has been specified after laboratory testing on different heats. Thermogravimetric analysis have been performed to differentiate materials (ferritic to austenitic grades) in terms of coking level and coking rate. Alloys have been classified versus their coking resistance in function of temperature showing the efficiency and  enhanced resistance of P9Mod solution.Ranking of materials after thermogravimetric analysis have demonstrated the impact and influence of Cr content. We have defined our new chemical analysis on P9 basis with adding of specific elements:

Si:together with Chromium drastically reduce the coking rate

Cu:together with Silicon also reduces the coking rate.If a weak zone appears on the oxide layer (cracks) then the catalytic effect of Iron will be reduced by the presence of Cu

Ni:is used to avoid delta ferrite (gamma-phase producing) formation and to improve toughness values

Different laboratory heats have been tested in order to define the right Si, Cu and Ni contents. New ranking after thermogravimetric analysis ,after 5 hours testing,gave a coking rate of P9Mod  10 times less than for P9.

Industrial heats have been produced and P9Mod tubes have been installed in European visbreaker during one year for field testing. Even if the process parameters were not the best one , results are showing the efficiency of P9Mod as coke resistant material and highest mechanical properties (thanks to alloying elements ) comparing to P9.


P9mod: Coke Resistant Tubes/pipes Developed by Vallourec for Refinery Furnaces

Division / Sponsors: 
Pressure Vessels & Piping (PVP)


Paper Proceedings: https://asmedigitalcollection.asme.org/PVP/PVP2020/volume/83815

PVP2020 - Virtual Conference

Supporting the need among researchers worldwide for additional online and multimedia content, ASME now offers the ASME Conference Video Collection. This platform will collect and provide long-term access to conference presentation videos, encompassing all technology areas within ASME's technical conference and events program. About 30,000-40,000 engineers across all mechanical engineering and related disciplines participate in ASME conferences each year. This includes authors of approximately 6,000 to 8,000 technical papers published by ASME, the majority of whom also submit video presentations for our virtual conferences. The video collection will be available as an add-on to existing product packages or as a separate subscription.