Aromatics extraction and distillation process
AssigneeUop LLC
InventorAnthony G. Vickers
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Abstract
An improved aromatics extraction process is disclosed. Key feature of the present invention is use of the fractionator in the hydrodealkylation unit or other unit with a benzene fraction to fractionate not only hydrodealkylated benzene but also extracted benzene. The extracted benzene is used as "pseudo" reflux in the hydrodealkylation unit fractionator, thereby reducing the reflux requirement. The conventional re-run fractionator for clay treated benzene extract is eliminated, since polymerized olefins in this extract are removed as a bottoms fraction from the hydrodealkylation fractionator.
Claims17
In a process for the fractionation of benzene in a benzene product fractionator wherein a benzene-rich stream is fed to an intermediate locus, benzene reflux is supplied to the top of the fractionator and benzene product is recovered from an upper portion of the fractionator, above the feed locus, and material heavier than benzene is recovered from a lower portion of the fractionator, the improvement which comprises supplying as at least a portion of the reflux requirement of the benzene fractionator a high purity, clay treated benzene fraction derived from an aromatics extraction unit, wherein the extracted, clay treated benzene is added to the benzene fractionator at a point between the benzene product withdrawal locus, and the feed locus of the fractionator.
In a process for the hydrodealkylation of alkylaromatics to benzene wherein a stream comprising toluene is charged to a hydrodealkylation zone to produce a benzene and toluene-rich dealkylation effluent containing trace amounts of olefins, the dealkylation effluent is passed through a clay treating zone for conversion of olefins to di-olefins, and heavier material, clay treated dealkylation effluent is introduced into an intermediate locus of benzene product fractionator wherein benzene reflux is supplied to the top of the fractionator and benzene product is recovered from an upper portion of the fractionator, above the feed locus, a toluene fraction is recovered from a lower portion of the fractionator for recycle to the hydrodealkylation unit, and heavy aromatics and polymerized olefins are removed as a bottoms fraction, the improvement which comprises:
- supplying as at least a portion of the reflux requirement of the benzene fractionator a high purity, clay treated benzene fraction derived from an aromatics extraction unit, wherein the extracted, clay treated benzene is added to the benzene fractionator at a point between the benzene product withdrawal locus and the feed locus of the fractionator.
A combination aromatics extraction and dealkylation process comprising:
- a. extracting benzene from a benzene-rich fraction;
- b. passing at least a portion of the extracted benzene through a first clay treating zone;
- c. introducing clay treated benzene into a benzene fractionator at a first locus, in an upper portion thereof;
- d. dealkylating a toluene-rich fraction to produce a benzene- and toluene-rich dealkylation effluent;
- e. passing at least a portion of the dealkylation effluent through a second clay treating zone;
- f. introducing clay treated dealkylation effluent into the benzene fractionator at a second locus, below said first locus;
- and,
- g. withdrawing a benzene product from the benzene fractionator at a third locus above said first locus.
Dependencies are inferred from the claim text.