Patent ID: 9272256
Filing Date: 2016-03-01
CPC Classification: B01J,C10G,C22C

Claim Text:
1. A process for treating a hydrocarbon stream containing hydrogen sulfide, the process comprising: flowing the hydrocarbon stream containing hydrogen sulfide through a hydrocarbon treating vessel; heating at least a portion of an interior surface of the vessel to a predetermined vessel temperature of 565° C. or greater for 1,000 hours or more; allowing a portion of the hydrogen sulfide to interact with oxygen and air within the vessel to form polythionic acid and controlling stress corrosion cracking of the portion due to the polythionic acid; controlling sensitization of the portion of the hydrocarbon treating vessel by employing a hydrocarbon treating vessel with at least the portion thereof formed of a low-carbon stainless steel alloy having a Pa value below 0.10 comprising 0.005 to 0.020 wt-% carbon, 9.0 to 13.0 wt-% nickel, 17.0 to 19.0 wt-% chromium, 0.20 to 0.50 wt-% niobium, and 0.06 to 0.10 wt-% nitrogen to restrict sensitization of the portion of the interior surface; and intermittently stopping flowing the hydrocarbon stream, reducing the vessel temperature below the predetermined temperature, and exposing the interior of the hydrocarbon treating vessel to an external environment including oxygen and moisture without neutralizing or purging the interior of the hydrocarbon treating vessel and without causing polythionic acid stress corrosion cracking of the portion of the interior surface.