US 5,360,533 AGranted

Direct dry gas recovery from FCC reactor

AssigneeUop LLC

InventorsConstante P. Tagamolila, Edward C. Haun, David A. Lomas, Joseph E. Zimmermann

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Abstract

A FCC product recovery section operates at greater efficiency by recovering separate riser product streams and reactor product streams and quenching and absorbing lighter, more valuable hydrocarbon products from the reactor product stream in separate quench and absorption vessels. The quench and absorbtion vessels are intergrated with a main fractionator and gas concentration section of a typical FCC product recovery section. Heavy hydrocarbons, clarified oil and/or cycle oil absorb hydrocarbons from the reactor product stream in the quench and absorption vessels and return the absorbed products to the main fractionator while net gasoline product from the reactor product stream enter the primary absorber of the gas concentration section. This arrangement is particularly useful in increasing the product recovery capacity of an existing FCC product separation section.

Claims21

Dependent claims

A process for the fluidized catalytic cracking (FCC) of an FCC feedstock and the recovery of a riser effluent stream and a reactor effluent stream, said process comprising:

a) passing an FCC feedstock and regenerated catalyst particles to a reactor riser and transporting said catalyst and feedstock through said riser to convert said feedstock;
b) discharging a mixture comprising catalyst particles and gaseous hydrocarbons from a discharge end of said riser directly into a separation zone, separating gaseous hydrocarbons from catalyst containing adsorbed hydrocarbons and recovering a riser effluent stream from said separation zone;
c) passing said catalyst containing adsorbed hydrocarbons from said separation zone into a reaction vessel and withdrawing a reactor effluent stream from said reactor vessel;
d) separating said riser effluent stream in a primary fractionation zone and recovering fractions comprising a heavy hydrocarbon stream, a light cycle oil stream and a gasoline stream;
e) passing said reactor effluent stream to a reactor quench zone and contacting said reactor effluent stream with at least a portion of at least one of said fractions in said quench zone to absorb C.sub.3 and higher hydrocarbons from said reactor effluent stream and produce a quenched overhead stream and a primary recycle stream;
f) returning at least a portion of said primary recycle stream to said primary fractionation zone;
g) passing at least a portion of said quenched overhead stream to a reactor absorber and contacting said at least a portion of said quenched overhead stream with at least a portion of said light cycle oil stream in said reactor absorber to absorb C.sub.3 and higher hydrocarbons from said quenched overhead stream and produce a reactor gas stream comprising C.sub.2 hydrocarbons and lower boiling gases and a C.sub.3 rich light cycle oil stream;
and,
h) returning said C.sub.3 rich light cycle oil stream to said primary fractionation zone.

6 more elements

A process for the fluidized catalytic cracking (FCC) of an FCC feedstock and the recovery of a riser product stream and a reactor product stream, said process comprising:

a) passing said FCC feedstock and regenerated catalyst particles to a reactor riser and transporting said catalyst and feedstock upwardly through said riser thereby converting said feedstock to a riser gaseous product stream;
b) discharging a mixture of catalyst particles and gaseous products from a discharge end of said riser directly into a disengaging vessel, separating gaseous components from catalyst containing adsorbed hydrocarbons in said disengaging vessel and recovering a riser product stream from said disengaging vessel;
c) passing said catalyst containing adsorbed hydrocarbons from said disengaging vessel into a reaction vessel, maintaining a dense bed of catalyst in said reaction vessel and withdrawing a reactor product stream from said reactor vessel;
d) passing spent catalyst from said reactor vessel into a regeneration zone and contacting said spent catalyst with a regeneration gas in said regeneration zone to combust coke from said catalyst particles and produce regenerated catalyst particles for transfer to said reactor riser;
e) separating said riser product stream in a primary fractionation zone and producing a heavy hydrocarbon stream, a light cycle oil stream and a gasoline stream;
f) condensing said gasoline stream and separating said gasoline stream into a first vapor gasoline fraction and a first liquid gasoline fraction;
g) passing said reactor product stream to a reactor quench zone and contacting said reactor product stream with a portion of said heavy hydrocarbon stream in said quench zone to absorb C.sub.3 and higher hydrocarbons from said reactor product stream and produce a quenched overhead stream and a heavy hydrocarbon recycle stream and returning said heavy hydrocarbon recycle stream to said primary fractionation zone;
h) separating said quenched overhead fraction into a first absorber gas stream and a first recycle liquid and passing at least a portion of said first recycle liquid to said primary fractionation zone;
i) separating said first absorber gas into a second absorber gas stream and a second recycle liquid;
j) passing said second absorber gas stream to a reactor absorber and contacting said second absorber gas with a portion of said light cycle oil stream in said reactor absorber to absorb C.sub.3 and higher hydrocarbons from said second absorber gas and produce a reactor gas stream comprising C.sub.2 hydrocarbons and lower boiling gases and a C.sub.3 rich light cycle oil stream and returning said C.sub.3 rich light cycle oil stream to said primary fractionation zone;
k) combining said second recycle liquid with said first vapor gasoline fraction and separating the combined stream into a second vapor gasoline fraction and second gasoline liquid fraction;
l) stripping and debutanizing said second gasoline fraction to produce a gasoline product stream;
and,
m) contacting said second gasoline vapor stream with a portion of at least one of said gasoline product stream and said first liquid gasoline fraction to absorb C.sub.2 and lower boiling hydrocarbons and produce a light gas stream and a gasoline recycle stream.

11 more elements

A process for the fluidized catalytic cracking (FCC) of an FCC feedstock and the recovery of a riser product stream and a reactor product stream, said process comprising:

a) passing said FCC feedstock and regenerated catalyst particles to a reactor riser and transporting said catalyst and feedstock upwardly through said riser thereby converting said feedstock to a riser gaseous product stream;
b) discharging a mixture of catalyst particles and gaseous products from a discharge end of said riser directly into a separation zone, separating gaseous components from catalyst containing adsorbed hydrocarbons in said disengaging vessel and recovering a riser product stream from said separation zone;
c) passing said catalyst containing adsorbed hydrocarbons from said separation zone into a reaction vessel, maintaining a dense bed of catalyst in said reaction vessel and withdrawing a reactor product stream from said reactor vessel;
d) separating said riser product stream in a primary fractionation zone and producing a heavy hydrocarbon stream, a light cycle oil stream and a gasoline stream;
e) condensing said gasoline stream and separating said gasoline stream into a first vapor gasoline fraction and a first liquid gasoline fraction;
f) passing said reactor product stream to a reactor quench zone and contacting said reactor product stream with a portion of said heavy hydrocarbon stream in said quench zone to absorb C.sub.3 and higher hydrocarbons from said reactor product stream and produce a quenched overhead stream and a heavy hydrocarbon recycle stream and returning said heavy hydrocarbon recycle stream to said primary fractionation zone;
g) condensing said quenched overhead stream and separating said quenched overhead stream into a first absorber gas stream and a first recycle liquid and passing at least a portion of said first recycle liquid to said to said primary fractionation zone;
h) condensing said first absorber gas stream and separating said first absorber gas stream into a second absorber gas stream and a second recycle liquid;
i) combining said second recycle liquid with said first vapor gasoline fraction and separating the combined stream into a second vapor gasoline fraction and second gasoline liquid fraction;
j) stripping and debutanizing said second gasoline fraction to produce a gasoline product stream;
k) contacting said second gasoline vapor stream with a portion of said gasoline product stream and a portion of said first liquid gasoline fraction to absorb C.sub.2 and lower boiling hydrocarbons and produce a light gas stream and a gasoline recycle stream and recycling said gasoline recycle stream to said first gasoline vapor stream;
and,
l) contacting said light gas stream and said second absorber gas stream with a portion of said light cycle oil in a secondary absorber to absorb C.sub.4 and higher boiling hydrocarbons, recycling the light cycle oil from said secondary absorber to said primary fractionation zone and recovering a net gas stream from said secondary absorber.

10 more elements

Dependencies are inferred from the claim text.