When Sulfidation damage is found, it most often (usually) appears as:

• Localized corrosion    

• High velocity erosion-corrosion

• Uniform thinning

• Under-deposit (scale) corrosion

Hydrochloric acid (aqueous HCl) in a very wide range of concentrations causes:

• General corrosion that is very aggressive to both CS & Low alloy steel

• Localized corrosion that is very aggressive to both CS & Low alloy steel

• General & localized corrosion that is very aggressive to CS, Low alloy steel and SS

• General & localized corrosion very aggressive to most common refinery construction mat’ls

Regarding acidic corrosion, at a given pressure, H²S concentration in sour water_____

• Increases as the temperature increases

• Increases as the temperature decreases

• Decreases as the temperature increases

• Decreases as the temperature decreases

Caustic embrittlement is a form of stress corrosion cracking characterized by Surface- initiated cracks in piping and equipment exposed to caustic and located:

• In the HAZ of welds always 

• Most often in the HAZ of welds

• Mostly adjacent to Non-PWHT welds

• mostly adjacent to zones of high stress

  Which statement is FALSE regarding Caustic Corrosion?

• A concentrating mechanism is not required to build up caustic strength

• Caustic may become concentrated by DNB, evaporation and deposition

• Alkaline salts may enter process streams through leaks in condensers or process equipment

• Process units use caustic solutions for neutralization & sulfur or chlorine compound removal

Crude and vacuum unit piping and vessels exposed to naphthenic acids in some crude oils may suffer which type of damage and severe metal loss when the specific factors of temperature, velocity, and sulfur content are considered?

• Erosion

• Erosion-corrosion

• Caustic corrosion

• Sulfidation

Amine cracking (form of Alkaline SCC) is more likely to occur in which services?

• MDEA &

  DGA

• ADIP & DGA

• MEA & DEA

• DIPA & DGA

Critical factors for Chloride SCC include all of the following EXCEPT:

• Chloride content

• pH & temperature

• Alloy composition

•   Stress & presence of CO²

Main concern during start-up, shutdown and/or hydrotesting for equipment/piping operating at elevated temps and this event can also occur in an auto refrigeration event in units processing light hydrocarbons:

• Stress fracture

•   Carburization

• Spheroidization

• Brittle fracture

Critical Environmental Factors for CUI can include all of the following EXCEPT:

   

• Insulation system design & type

• Humidity & Rainfall

• Chlorides from Marine Environment

• Industrial pollution (SO², etc)