102
running on high severity. Hence, a higher yield of coke and gas is also observed;
however, it is offset by increased margins due to high propylene yield.
Since hydrogen transfer is a bimolecular reaction, reducing the hydrocarbon partial pressure will shift the reaction’s equilibrium toward olefins [25]. Hence, optimizing reactor–regenerator pressure balance and/or addition of high amount of
diluents (steam) to the riser is advisable if propylene maximization is intended.
Modern high-severity FCC units (PFCC, HSFCC, DCC, etc.), which are designed
for high propylene yield, consume high amounts of steam for this purpose.
Feed characteristics also affect propylene yield. Feeds having a high hydrogen to
carbon ratio and a lower amount of contaminants generally favor the yield of light
Fig. 24 Changes in light olefin yield with temperature [88]
Fig. 25 Changes in propylene yield with HTI [88]
A. R. Khande et al.
running on high severity. Hence, a higher yield of coke and gas is also observed;
however, it is offset by increased margins due to high propylene yield.
Since hydrogen transfer is a bimolecular reaction, reducing the hydrocarbon partial pressure will shift the reaction’s equilibrium toward olefins [25]. Hence, optimizing reactor–regenerator pressure balance and/or addition of high amount of
diluents (steam) to the riser is advisable if propylene maximization is intended.
Modern high-severity FCC units (PFCC, HSFCC, DCC, etc.), which are designed
for high propylene yield, consume high amounts of steam for this purpose.
Feed characteristics also affect propylene yield. Feeds having a high hydrogen to
carbon ratio and a lower amount of contaminants generally favor the yield of light
Fig. 24 Changes in light olefin yield with temperature [88]
Fig. 25 Changes in propylene yield with HTI [88]
A. R. Khande et al.