Sour Corrosion Failures in Hydrocracker Reactor Effluent Air Cooler System

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Research areas:
Year:
2016
Type of Publication:
Article
Keywords:
REAC, Flow Regime, H2S Partial Pressure, Dissolved Oxygen, Temperature Difference
Authors:
Mohamed M. Refaat; Mohamed H. Hassanean; Moustafa E. Awad
Journal:
IJAIM
Volume:
4
Number:
4
Pages:
162-168
Month:
January
ISSN:
2320-5121
Abstract:
Middle East Oil Refinery (MIDOR) constructed and put into operation a single stage hydrocracker unit in the second quarter of 2001. Since its start-up, the unit has operated smoothly by hydrocracking a blend of straight run vacuum gasoil and heavy coker gasoil with total sulfur content of 2.98 wt.%, total nitrogen content of 1398 ppmw, and with sp.gr 0.92 at 60 °f. However, in the third quarter of 2003, a leakage in one of reactor effluent air cooler (REAC) tubes was registered and the unit had to be followed emergency shutdown procedures. A significant amount of deposits was found in the tubes of the REAC. According of the data from MIDOR laboratory, the following composition of the deposit was 1 wt.% NH4HS, 74.75 wt.% FeS, 19.11% Fe2O3, 1.54 wt.% SiO2 and about 3.6 wt.% carbonaceous matter. From this time, the unit had experienced corrosion in the tubes of the REAC about 7 failures ended with tube explosion of hydrocracking REAC in the third quarter of 2009. In the present paper, root causes for several failures of hydrocracking REAC were studied to promote system reliability. Some of the major causes for several failures were relatively high PH2S to carbon steel, high dissolved oxygen in wash water which proved by analysis of deposit and wash water, and flow regime.
Full text: IJAIM-522_Final.pdf

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