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US 12,037,314 B2Granted
Processes for isomerizing C8 aromatic hydrocarbons
AssigneeExxonMobil Engineering & Technology Company
InventorsRobert G. Tinger, Hari Nair, Todd E. Detjen, Paul Podsiadlo, Travis D. Sparks
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Abstract
A liquid phase isomerization process comprising cofeeding molecular hydrogen at a feeding rate ≥100 ppm by weight can effectively convert a C8 aromatic hydrocarbon isomerization feed in the presence of an isomerization catalyst with a very low deactivation rate of the catalyst, even at high WHSV ≥5 hour−1.
Claims25
A process comprising:
- co-feeding molecular hydrogen and a liquid phase isomerization hydrocarbon feed comprising C8 aromatic hydrocarbons into an isomerization reactor having a ZSM-5 isomerization catalyst disposed therein, wherein the co-feeding comprises feeding the molecular hydrogen at a feeding rate from 200 ppm to less than or equal to 1000 ppm by weight, based on the total weight of the isomerization hydrocarbon feed;
- and
- contacting the molecular hydrogen and the C8 aromatic hydrocarbons with the ZSM-5 isomerization catalyst under isomerization conditions in the isomerization reactor to produce an isomerization effluent, wherein the isomerization conditions comprise a reaction pressure in the isomerization reactor from 1,700 kPa-gauge to 3,500 kPa-gauge and a reaction temperature such that the C8 aromatic hydrocarbons are substantially in a liquid phase in the isomerization reactor, and a weight hourly space velocity from 5 to 20 hour−1.
A process for producing p-xylene, the process comprising:
- co-feeding molecular hydrogen and a liquid phase isomerization hydrocarbon feed comprising C8 aromatic hydrocarbons into an isomerization reactor having a ZSM-5 isomerization catalyst disposed therein, wherein the co-feeding comprises feeding the molecular hydrogen at a feeding rate from 200 ppm to less than or equal to 1000 ppm by weight, based on the total weight of the isomerization hydrocarbon feed;
- and
- contacting the molecular hydrogen and the C8 aromatic hydrocarbons with the ZSM-5 isomerization catalyst under isomerization conditions in the isomerization reactor to produce an isomerization effluent, wherein the isomerization conditions comprise a reaction pressure from 1,700 kPa-gauge to 3,500 kPa-gauge and a reaction temperature of from 200 to 300° C. such that the C8 aromatic hydrocarbons are substantially in a liquid phase in the isomerization reactor, and a weight hourly space velocity from 5 to 20 hour−1;
- the isomerization effluent comprises p-xylene at a concentration higher than the isomerization hydrocarbon feed;
- and
- recovering at least a portion of the p-xylene from the isomerization effluent.
3 more elements
Dependencies are inferred from the claim text.