Q & A > Question Details
My question relaters to the maximum temperature that can be reached in the feed preheater furnace in FCC unit. We operate one of our FCC units in maximum distillates mode and we want to decrease cat/oil to minimum. Currently, we have the following design limits in the feed preheater furnace: 360C (680 F) in the process size and 419C (786F) in the skin points of the furnace tubes. According to a study by our engineering department, temperature in the skin points could be increased to 467C (873F). But our main concern is that an increase in temperature in furnace tubes could cause coking of the feed. Although the feed to the unit is Mild Hydrocracker residue, that has low tendency to coking.
Has anyone experience running FCC units at feed preheat temperatures higher that 360C (680F) in process / 419C (786F) in skin point?
21/02/2016 A: Andrey Sysoev, CJSC TH Strommashina, strommash42@gmail.com
About furnaces of indirect heating: http://strommashina.com/catalog/kilns-furnaces-of-indirect-heating
20/01/2012 A: Celso Pajaro, Sulzer Chemtech, celso.pajaro@sulzer.com
Besides evaluating the maximum temperature that you heater tubes can achieved, you have to make sure that feed will not flash at the new conditions, a small amount of vapor can increase nozzle erosion, in one case nozzles eroded in 12 months.