Question
-
Is it possible that refiners could be overlooking some practical solutions to increasing FCC olefins yields, such as in the gas plant/recovery section?
Feb-2023
Answers
-
Bani Cipriano, W. R. Grace & Co, bani.cipriano@grace.com
The yield of light olefins from the FCC can be increased by optimising different FCC process variables, including riser operating temperature (ROT), injection of ZSM-5 additives, hydrocarbon partial pressure, and the recycle of light naphtha, C4 or oligomer streams into the FCC. Increasing the yield of light olefins increases the load on the wet gas compressor (WGC) and the gas plant.
The FCC unit can realise maximum value within unit constraints by optimising the appropriate variables, and it is important not to overlook catalytic solutions to these constraints. For example, by increasing the yield of light olefins via ZSM-5 additives versus ROT increase, it is possible to make more light olefins per unit of dry gas production and, therefore, for a given unit limitation on the WGC and the gas plant.
Furthermore, in high metals applications, using an appropriate coke-selective catalyst with metals trapping functionality can result in lower H2 make, which further offloads the WGC and gas plant. In both cases, an increase in recovery of light olefins is enabled. As the cost of propylene production from the FCC is lower than other propylene production routes, the use of catalytic solutions or minor revamps to overcome the gas plant handling capacity are effective ways of realising the maximum value from the FCC.
Feb-2023
SPONSORS