The benefits of hydrotreating Fluid Catalytic Cracker (FCC) feed are well known in the refining industry. The FCC unit has improved operation with feeds containing low contaminants (metals), high hydrogen, and low sulfur. The main purpose of the VGO hydrotreater/FCC pretreat hydrotreater is to generate high quality feed to the FCC unit by improving the quality of the VGO via contaminants removal and an increase in the hydrogen content.
Pretreatment is important because a reduction in the feed stream sulfur content translates to lower sulfur levels achieved in FCC gasoline product which helps to meet the increasingly stringent global clean fuels specifications. For example, a 1,200 ppm sulfur concentration in the FCC feed is converted to approximately 60 ppm sulfur content in FCC product gasoline. Thoughtfully designed FCC pretreat hydrotreaters may remove the need for further downstream hydrotreating to reduce fuel sulfur content.
Pretreating the FCC feed also helps to minimize octane losses associated with saturating olefins and aromatics which are undesirable results of hydrotreating the FCC product streams. The lower sulfur content of the FCC feed also translates to lower SOx emissions from the FCC regenerator further assisting the refiner in being an environmental steward.
The lower nitrogen content of the pretreated FCC feed increases catalytic cracking activity which results in higher conversion and FCC gasoline yields. Furthermore, a reduction in the metals content of the FCC feed translates to a reduction in FCC catalyst deactivation.
The IsoTherming® technology for VGO hydrotreating enables increased conversion in the FCC unit and improved gasoline and diesel yields. To date, there are two IsoTherming® VGO hydrotreaters in commercial operation.
50,000 BPSD/311 m3/h
< 800 ppm sulfur
59,105 BPSD/392 m3/h
< 1000 ppm sulfur