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US 10,273,196 B2Granted
Hydrocarbon dehydrocyclization
AssigneeExxonMobil Chemical Patents Inc.
InventorsPaul F. Keusenkothen, John S. Buchanan, John S. Coleman, Seth M. Washburn
Life of this patent
Estimating the term…
Abstract
The invention relates to hydrocarbon dehydrocyclization to produce products such as aromatic hydrocarbon, to equipment and materials useful for dehydrocyclization, to processes for carrying out dehydrocyclization, and to the use of dehydrocyclization for, e.g., natural gas upgrading. The dehydrocyclization is carried out in a catalytic reaction zone of a reverse-flow reactor.
Claims18
A hydrocarbon dehydrocyclization process, the process comprising:
- (a) providing a feed comprising C2+ non-aromatic hydrocarbon;
- (b) providing an oxidant and a gaseous fuel;
- (c) providing a reverse-flow reactor, the reverse-flow reactor including
- (i) a pre-heated reaction zone, and
- (ii) a dehydrocyclization catalyst located in the reaction zone, the dehydrocyclization catalyst comprising a molecular sieve component and a dehydrogenation component;
- (d) during a first time interval,
- (i) establishing a forward flow of the feed to the reaction zone,
- (ii) transferring heat from the reaction zone to the feed to produce a heated feed and a cooled reaction zone,
- (iii) reacting at least a portion of the heated feed flow's C2+ non-aromatic hydrocarbon in the presence of the dehydrocyclization catalyst under dehydrocyclization conditions which include a temperature of 400° C. to 700° C. and a pressure ≥0 psi gauge (psig) (101 kPa) to produce a forward flow of a reaction product comprising molecular hydrogen and aromatic hydrocarbon,
- (iv) depositing coke on or proximate to the dehydrocyclization catalyst,
- (v) conducting the forward flow of reaction product from the reaction zone and away from the reverse-flow reactor, and
- (vi) decreasing the feed flow to the reaction zone;
- and
- (e) during a second time interval,
- (i)establishing a reverse flow of the fuel and a reverse flow of the oxidant toward the reverse-flow reactor, the oxidant flow comprising first and second portions of the oxidant,
- (ii) combusting the first portion of the oxidant flow under combustion conditions with at least a portion of the fuel flow outside of the reaction zone to produce a reverse flow of a first combustion product toward the reaction zone,
- (iii) combusting within the reaction zone the second portion of the oxidant flow with at least a portion of the deposited coke to produce a reverse flow of a second combustion product in the reaction zone,
- (iv) conducting the reverse flows of the first and second combustion products away from the reaction zone and out of the reverse-flow reactor, wherein heat is transferred from the combustion products to the reaction zone to re-heat the reaction zone, and
- (v) decreasing the reverse flow of fuel and the reverse flow of oxidant,
- wherein the combustion of step (e)(ii) is carried out in the presence of a catalytically effective amount of at least one selective combustion catalyst, ≥95 wt. % of the fuel flow is combusted in the presence of the selective combustion catalyst, and the reaction zone has a non-monotonic temperature profile at the end of step (e).
17 more elements
A hydrocarbon conversion process, comprising:
- (a) providing a feed comprising C2+ non-aromatic hydrocarbon;
- (b) providing an oxidant and a gaseous fuel, the fuel and oxidant having a characteristic molar ratio Mc for stoichiometric combustion of the fuel;
- (c) providing a reverse-flow reactor, the reverse-flow reactor including
- (i) a pre-cooled heat-transfer zone,
- (ii) a pre-heated reaction zone opposed to the heat-transfer zone,
- (iii) a third zone located between the heat-transfer and reaction zones, the third zone being in fluidic communication with the heat-transfer and reaction zones,
- (iv) a dehydrocyclization catalyst located in the reaction zone, the dehydrocyclization catalyst comprising a molecular sieve component and a dehydrogenation component, and
- (v) at least one pre-oxidized solid oxygen carrier (SOC) in the reaction zone;
- (d) during a first time interval having a time duration of no more than 90 seconds,
- (i) establishing a forward flow of the feed to the reaction zone,
- (ii) transferring heat from the reaction zone to the feed to produce a heated feed and a cooled reaction zone,
- (iii) reacting the flow of heated feed in the presence of the dehydrocyclization catalyst under dehydrocyclization conditions which include an average temperature ≥400° C. and a pressure ≥0 psi gauge (psig) (101 kPa) to produce a forward flow of a reaction product comprising molecular hydrogen and aromatic hydrocarbon, a deviation in temperature across the dehydrocyclization catalyst in the reaction zone at a beginning of the first time interval being 10% or less of the average temperature in °C.,
- (iv) increasing aromatic hydrocarbon yield by reducing the pre-oxidized SOC to release oxygen. and combusting at least a portion of the released oxygen with at least a portion of the reaction product's molecular hydrogen
- (v) depositing coke on or proximate to the dehydrocyclization catalyst,
- (vi) conducting the forward flow of reaction product from the reaction zone, through the third and heat-transfer zones, and away from the reverse-flow reactor, wherein heat is transferred from the reaction product to the heat-transfer zone to heat the heat-transfer zone, and
- (vii) decreasing the teed flow to the reaction zone;
- and
- (e) during a second time interval,
- (i) establishing a reverse flow of the fuel and a reverse flow of the oxidant to the heat-transfer zone at an oxidant flow :
- fuel flow molar ratio >Mc, and transferring heat from the heat-transfer zone to at least the oxidant flow to re-cool the heat-transfer zone,
- (ii) producing a reverse-flow of combustion products by combusting with the heated oxidant flow (A) at least a portion of the deposited coke and (B) at least a portion of the fuel flow, wherein ≥50 wt. % of the fuel flow combustion occurs in the heat-transfer zone and/or the third zone,
- (iii) re-oxidizing the SOC with a third portion of the oxidant flow
- (iv) conducting the reverse flow of combustion products away from the reaction zone and out of the reverse-flow reactor, wherein heat is transferred from the combustion products to the reaction zone to re-heat the reaction zone, and
- (v) decreasing the reverse flow of fuel and the reverse flow of oxidant to the heat-transfer zone.
21 more elements
Dependencies are inferred from the claim text.