Ecopetrol's integrity evaluation programme: A case study of a refinery furnace evaluation

This paper presents the relation between internal carburization of tubes fabricated in a ferritic 9Cr-1Mo steel and their mechanical properties in tension and impact, before and after operation for operating times of 14 400, 50 400, 64 800 and 72 000 h in the radiation zone of the visbreaking furnace of the Cartagena Refinery. The skin temperature of the tubes was 566 degrees C, on average, and the fluid temperature (heavy hydrocarbons) was 485degrees C. The carburized layer was observed to have a depth of 1.6 mm and a maximum concentration of 0.775% C on the internal surface of the tube with 72 000 h of continuous operation.

Keywords:

• Visbreaking Furnace
• Carburizing
• Mechanical Properties
• Cr-1mo Steel