Main column separation of FCC product effluent
First Claim
1. In a fluid catalytic cracking process, wherein a hydrocarbonaceous charge stock is converted into lower-boiling hydrocarbons in contact with finely-divided catalyst particles, the method of separating catalyst-containing, catalytically-cracked product effluent which comprises the steps of:
- a. introducing said product effluent into a first fractionation column through a first locus in the bottom portion thereof;
b. withdrawing a light naphtha fraction from a second locus in the upper portion of said column, condensing and separating said light naphtha fraction to provide (i) a first vaporous phase and, (ii) a liquid phase;
c. recycling a first portion of said liquid phase, as a reflux stream, to said first column through a third locus below said second locus, and introducing a second portion into a second fractionation column;
d. separating said second portion to provide (i) a second vaporous phase and, (ii) a light naphtha product stream;
e. withdrawing a heavy naphtha fraction from said first column, through a fourth locus below said third locus, and introducing at least a portion thereof into a third fractionation column;
f. separating the portion of said heavy naphtha fraction to provide (i) a heavy naphtha bottoms product stream substantially free from light naphtha and, (ii) a light naphtha containing overhead stream;
g. introducing at least a portion of said overhead stream into said first column through a fifth locus intermediate said third and fourth loci; and
,h. withdrawing a catalyst-containing slurry oil fraction from said first column through a sixth locus below said first locus.
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Accused Products
Abstract
Separation of the catalyst-containing product effluent from a fluid catalytic cracking unit is effected in the main column by a technique which involves removing a light naphtha fraction as the single overhead stream and separately withdrawing a heavy naphtha fraction as a lower side-cut. The latter is stripped of light naphtha (for recycle to the main column) and recovered as a product stream. Preferably a portion of the heavy naphtha fraction (as withdrawn) is cooled and combined with the light naphtha overhead reflux stream.
29 Citations
7 Claims
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1. In a fluid catalytic cracking process, wherein a hydrocarbonaceous charge stock is converted into lower-boiling hydrocarbons in contact with finely-divided catalyst particles, the method of separating catalyst-containing, catalytically-cracked product effluent which comprises the steps of:
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a. introducing said product effluent into a first fractionation column through a first locus in the bottom portion thereof; b. withdrawing a light naphtha fraction from a second locus in the upper portion of said column, condensing and separating said light naphtha fraction to provide (i) a first vaporous phase and, (ii) a liquid phase; c. recycling a first portion of said liquid phase, as a reflux stream, to said first column through a third locus below said second locus, and introducing a second portion into a second fractionation column; d. separating said second portion to provide (i) a second vaporous phase and, (ii) a light naphtha product stream; e. withdrawing a heavy naphtha fraction from said first column, through a fourth locus below said third locus, and introducing at least a portion thereof into a third fractionation column; f. separating the portion of said heavy naphtha fraction to provide (i) a heavy naphtha bottoms product stream substantially free from light naphtha and, (ii) a light naphtha containing overhead stream; g. introducing at least a portion of said overhead stream into said first column through a fifth locus intermediate said third and fourth loci; and
,h. withdrawing a catalyst-containing slurry oil fraction from said first column through a sixth locus below said first locus. - View Dependent Claims (2, 3, 4, 5, 6, 7)
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Specification