Maximizing Light Cycle Oil (Lco) production in fluid catalytic cracker

Abstract

Oil refining is an industrial process which involves separation, conversion and finishing. FCC centered refinery uses Fluid Catalytic Cracking Unit (FCCU) has the major conversion unit. FCCU is responsible for the production of petrol, LPG and Light Cycle Oil (LCO). Diesel is the most important fuel used in automobiles because of its high efficiency. The global demand for diesel is increasing than petrol but many older refineries have optimized their plant for producing more petrol than diesel. LCO is the diesel boiling range material, which is produced in addition to gas and petrol in the FCCU. LCO is treated in the diesel hydrotreater (DHT) unit to produce low sulphur environment friendly diesel. In this paper, production of LCO is increased in the FCCU by employing medium conversion mode rather than using traditional low conversion mode. Low conversion mode will cause a loss of gas production, deteriorate petrol octane rating and also increase the production of low valued slurry oil. With medium conversion technique both gas quality and quantity is maintained and improves the petrol octane rating. Medium conversion mode also reduces the amount of low valued slurry oil. Slurry oil contains LCO boiling range material in it, hence a separate slurry oil stripping tower is employed to recover the LCO from slurry oil. The control of Fluid Catalytic Cracking Unit is complicated as it involves numerous parameters to be monitored and controlled. Hence Distributed Control Systems (DCS) is employed to automate the FCCU Process.