(28c) Troubleshooting Jet-Fuel Production on Crude Distillation Unit in Pemex Cadereyta Refinery

This paper shows the troubleshooting and analysis that led to a successful modification on the jet-fuel draw-off tray of a crude distillation tower. The modification solved a problem of yield reduction and difficulties to maintain product specifications.

The problem was reviewed qualitatively and quantitatively using different methods proposed by famous authors in this field like Kister and Lieberman. We used process simulators, heat and material balances, mechanical drawings of tower internal construction, and flow sketches through sections inside the tower. By the use of these tools and the recommended bibliography we solved the problem and evaluated the modification after plant turndown.

The modification of the jet-fuel chimney tray allowed an enhanced performance, a more stable operation for tower profile control, and an increase in the naphtha yield by 1.2% and jet-fuel by 8.3%. All this led to an improvement on plant preheat train thermal stability which gave energy savings of around 5.4 MMUSD per year.

Due to the improved crude preheat resulting from the modification, a better desalting is achieved, the pre-flash tower takes more lights off the crude, which allow a better pressure control on atmospheric tower. A large reduction in fuel gas in fired heaters was achieved because of the increase in heater inlet temperature.

Yield increase of naphtha allows earnings of around 54.3 MMUSD per year. In addition, a potential jet-fuel earning could be achieved because of the production increase, which represents 55.3 MMUSD per year.