FCC process combining molecular separation with staged conversion
OwnerGeorge Swan, Bruce Cook +2inventors
InventorsGeorge Swan, Bruce Cook, B. Henry, Steven Lowenthal
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Abstract
This invention relates to fluid catalytic cracking (FCC) process for improving the quality of distillates suitable as blend stocks for diesel fuels. The FCC process combines staging the FCC conversion process with interstage molecular separation of multi-ring aromatic species. Lower and higher severity reaction zones in the riser of the FCC reactor are combined with selective molecular separations to improve the production of diesel quality distillates.
Claims15
A catalytic cracking process for enhancing the production of distillate suitable as a diesel fuel or blend stock for diesel fuel which comprises:
- (a) contacting hydrocarbon feed with catalyst in a two zone FCC reactor, said reactor comprising a first low severity zone and a second higher severity zone and said feed comprises a fresh feed and a recycled feed wherein the fresh feed is contacted with catalyst in the first zone and recycled feed is contacted with catalyst in the second zone to form combined cracked product;
- (b) separating combined cracked product from catalyst;
- (c) fractionating separated cracked product from step (b) into a naphtha fraction, a fraction containing diesel fuel or blend stock for diesel and a bottoms fraction;
- (d) passing the fraction from step (c) containing diesel fuel or blend stock for diesel fuel through a selective low energy molecular separation to produce a diesel fuel or blend stock for diesel fuel and a light cycle oil;
- (e) passing the bottoms fraction from step (c) through a second selective low energy molecular separation to produce a second bottoms fraction and a feed fraction;
- and
- (f) passing the feed fraction from step (e) as recycled feed to the second zone of step (a).
A catalytic cracking process for enhancing the production of distillate suitable as a diesel fuel or blend stock for diesel fuel which comprises:
- (a) contacting hydrocarbon feed with catalyst in a FCC process containing a first and second riser, said first riser comprising a low severity zone and said second riser comprising a higher severity zone, and said feed comprises a fresh feed and a recycled feed wherein the fresh feed is contacted with catalyst in the first riser to form a first cracked product and recycled feed is contacted with catalyst in the second riser to form a second cracked product;
- (b) combining the first and second cracked product to from a combined cracked product and separating combined cracked product from catalyst;
- (c) fractionating separated combined cracked product from step (b) into a naphtha fraction, a fraction containing diesel fuel or blend stock for diesel and a bottoms fraction;
- (d) passing the fraction from step (c) containing diesel fuel or blend stock for diesel fuel through a selective low energy molecular separation to produce a diesel fuel or blend stock for diesel fuel and a light cycle oil;
- (e) passing the bottoms fraction from step (c) through a second selective low energy molecular separation to produce a second bottoms fraction and a feed fraction;
- and
- (f) passing the feed fraction as recycled feed to the second riser of step (a).
A catalytic cracking process for enhancing the production of distillate suitable as a diesel fuel or blend stock for diesel fuel which comprises:
- (a) contacting hydrocarbon feed with catalyst in a riser of a FCC reactor, said riser comprises a low severity zone and a higher severity zone and said feed comprises a fresh feed and a recycled feed wherein the fresh feed and recycled feed are first contacted with catalyst in the higher severity zone to form combined cracked product;
- (b) separating cracked product from catalyst;
- (c) fractionating separated cracked product from step (b) into a naphtha fraction, a fraction containing diesel fuel or blend stock for diesel and a bottoms fraction;
- (d) passing the fraction from step (c) containing diesel fuel or blend stock for diesel fuel through a selective low energy molecular separation to produce a diesel fuel or blend stock for diesel fuel and a light cycle oil;
- (e) passing the bottoms fraction from step (c) through a second selective low energy molecular separation to produce a second bottoms fraction and a recycled feed fraction;
- and
- (f) combining the fresh feed and recycled feed fraction;
- and
- (g) contacting combined fresh feed and recycled feed with catalyst in step (a).
Dependencies are inferred from the claim text.