coker heater tubes metal

[Anonymous]

Date: 12 Aug 2005

is it possible from the metalorogy view point to make the last seven tubes of the coker heater from a metal which withstand skin temperature in the range of 730C ? We always suffer from high skin temperatures(677C) in the last three tubes(the nearest to the burners) of the heater short times( 30days) after steam spalling.the tubes metal is 9cr.
-Semon Jones

…copied form the old discussion forum

[Anonymous]

Some companys have gone to 347 S|S material to be able to run higher skin temps.

[Anonymous]

In our Upgrader, we use 9 Cr-1 Mo tubes for high skin temperatures and they can run until 1350ºF as maximum per design in On line spalling in accordance to API RP 530
 
Regards,
Euclides Prieto, BSIE, MSME
Inspection Engineer Lead – DCU Area
Hamaca Upgrader, Venezuela
eprieto@ameriven.com

[Gaetano Ambrosino]

A Uniform Temperature Distribution within the furnace is very important in eliminating the tube hot spots induced by flame impingements.
One of the problems encountered in refineryfire heaters is an imbalance in the heat flux in the individual heater passes. The imbalance can cause high coke formation rates and high tubes metal temperature, which reduce a units capacity and can cause premature failure.

The BOILERWATCH MMPII, Acoustic Pyrometer provides highly accurate temperature measurement of heat exchange and heat transfer performance; and allows monitoring of gas temperature conditions, and alerts plant operators concerning impending failures, reducing the frequency of unplanned shutdowns and Coke formation.

Please visit http://www.sciengr.com

[Author]

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