Fluid catalytic cracking in the oil & gas industry

Fluid catalytic cracking (FCC) is a process where the long chain hydrocarbon molecules in the lighter gas oil streams from the distillation columns are broken down into shorter molecules. In this way the feedstock produces mainly gasoline (known as petrol in Europe), and not diesel. Where there is a high demand for diesel fuel, this FCC process would not be used.

The feeds into the FCC reactor comprise the light gas oil streams, which are hot, and have been mixed with a catalyst: there is then another feed of steam into the bottom of the reactor. The gaseous reaction product gas then passes into a distillation column and various separators, producing output streams of fuel oil, naphtha and off gas. Such FCC processing units operate continuously 24 hours a day for as much as 2 to 3 years between shutdowns, so the reliability and long term performance of the fluid catalytic cracking instrumentation is of paramount importance.

KROHNE provides flow and level measurement solutions that are particularly suited to the demands created by continuous operation and the high temperatures normal in fluid catalytic crackers. The ultrasonic, electromagnetic and vortex flowmeters used for gas and liquid flow measurement have no mechanical moving parts, and offer no obstruction to the flow in the line. These instruments do not require flow conditioning plates or tubes, which means the pressure drop introduced is only the equivalent of a full bore piece of pipe with the same length as the meter. The KROHNE guided wave radar level and interface measurement systems used in the separators, settling tanks and even the distillation column also have no moving parts, only using a smooth vertical metal probe within the process vessel.