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US 2021/0387928 A1Published application
Isomerization Processes for Converting Aromatic Hydrocarbons Comprising Alkyl-Demethylation
OwnerMichel Molinier, Hari Nair +4inventors
InventorsMichel Molinier, Hari Nair, Meha Rungta, Michael Salciccioli, Doron Levin, Scott J. Weigel
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Abstract
Alkyl-demethylation of C2+-hydrocarbyl substituted aromatic hydrocarbons can be utilized to treat one or more of a heavy naphtha reformate stream, a hydrotreated SCN stream, a C8 aromatic hydrocarbon isomerization feed stream, a C9+ aromatic hydrocarbon transalkylation feed stream, and similar hydrocarbon streams to produce additional quantity of xylene products.
Claims23
A process for isomerizing C8 aromatic hydrocarbons, the process comprising:
- (i) providing a first C8 aromatic hydrocarbon stream comprising ethylbenzene, p-xylene, m-xylene, and optionally o-xylene;
- (ii) separating the first C8 aromatic hydrocarbon stream in a p-xylene recovery sub-system to obtain a p-xylene product stream and a p-xylene depleted stream;
- (iii) contacting at least a portion of the p-xylene depleted stream with a first ethyl-demethylation catalyst in a first ethyl-demethylation zone under a first set of ethyl-demethylation conditions to convert at least a portion of the ethylbenzene present in the p-xylene depleted stream to toluene to obtain a first ethyl-demethylation effluent exiting the first ethyl-demethylation zone, wherein the first ethyl-demethylation catalyst favors the conversion of ethylbenzene to toluene than to benzene under the first set of ethyl-demethylation conditions;
- (iv) contacting at least a portion of the first ethyl-demethylation effluent and optionally at least a portion of the p-xylene depleted stream with a first xylenes isomerization catalyst in a first xylenes isomerization zone under a first set of xylenes isomerization conditions to obtain a first xylenes isomerization effluent, wherein the first xylenes isomerization zone is separate from the first ethyl-demethylation zone;
- and
- (v) supplying at least a portion of the first xylenes isomerization effluent to the p-xylene recovery sub-system to obtain the p-xylene product stream and the p-xylene depleted stream.
3 more elements
A process for converting C8 aromatic hydrocarbons, the process comprising:
- (i) providing a first C8 aromatic hydrocarbon stream comprising ethylbenzene, p-xylene, m-xylene, and optionally o-xylene;
- (ii) separating the first C8 aromatic hydrocarbon stream in a p-xylene recovery sub-system to obtain a p-xylene product stream and a p-xylene depleted stream;
- (iii) contacting at least a portion of the p-xylene depleted stream with a first ethyl-demethylation catalyst in a first ethyl-demethylation zone under a first set of ethyl-demethylation conditions to convert at least a portion of the ethylbenzene present in the p-xylene depleted stream to toluene to obtain a first ethyl-demethylation effluent exiting the first ethyl-demethylation zone, wherein the first ethyl-demethylation catalyst favors the conversion of ethylbenzene to toluene than to benzene under the first set of ethyl-demethylation conditions;
- (iv) contacting at least a portion of the first ethyl-demethylation effluent and optionally at least a portion of the p-xylene depleted stream with a first xylenes isomerization catalyst in a first xylenes isomerization zone separate from the first ethyl-demethylation zone under a first set of xylenes isomerization conditions to obtain a first xylenes isomerization effluent;
- and
- (v) supplying at least a portion of the first xylenes isomerization effluent to the p-xylene recovery sub-system to obtain the p-xylene product stream and the p-xylene depleted stream;
- wherein:
- the first set of ethyl-demethylation conditions comprise:
- a temperature in a range from 200 to 500° C.;
- an absolute pressure in a range from 350 to 2500 kilopascal;
- a molar ratio of molecular hydrogen to hydrocarbon in a range from 0.5 to 20;
- and a weight hourly space velocity in a range from 1 to 20 hour−1;
- and
- the first ethyl-demethylation catalyst comprises a first metal element selected from groups 7, 8, 9, and 10 metals and combinations thereof, and a support.
11 more elements
Dependencies are inferred from the claim text.