Hydrocarbon dehydrocyclization

Patent metadata

Field	Value
Publication number	US-10273196-B2
Application number	US-201615240531-A
Country	US
Kind code	B2
Filing date	Aug 18, 2016
Priority date	Sep 25, 2015
Publication date	Apr 30, 2019
Grant date	Apr 30, 2019

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.

First claim

The invention claimed is:

1. A hydrocarbon dehydrocyclization process, the process comprising:
(a) providing a feed comprising C 2+ 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 C 2+ 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).

2. The process of claim 1 , wherein
(i) the pressure is in the range of from 0 psig (101 kPa) to 300 psig (2170 kPa),
(ii) the dehydrocyclization conditions further include a space velocity (GHSV) ≥1100 hr −1 , and
(iii) the first time interval has a duration in the range of from 0.01 seconds to 30 seconds.

3. The process of claim 1 , wherein the first time interval is in the range of from 0.1 seconds to 10 seconds.

4. The process of claim 3 , wherein the first portion of the oxidant flow is ≥50wt. % of the oxidant flow.

5. The process of claim 1 , wherein the feed comprises ≥75 wt. % of the C 2+ non-aromatic hydrocarbon, the C 2+ non-aromatic hydrocarbon comprising 10 wt. % to 40wt. % ethane, 20 wt. % to 50 wt. % propane, 20 wt. % to 50 wt. % butanes, and substantially saturated C 5+ hydrocarbon; and wherein the feed further comprises 1 wt. % or more of methane.

6. The process of claim 1 , wherein
(i) the combustion conditions include combusting in the reaction zone ≥95 wt. % of the deposited coke and combusting ≥85 wt. % of the fuel flow outside of the reaction zone,
(ii) the temperature of the dehydrocyclization catalyst during step (e) is ≤650° C.,
(iii) the second time interval is in the range of from 0.1 second to 500 seconds, and
(iv) the process includes repeating steps (d) and (e).

7. The process of claim 1 , wherein the dehydrocyclization catalyst includes
(i) at least 50 wt. % of the molecular sieve component, the molecular sieve component comprising one or more of MCM-22, ZSM-5, ZSM-11, ZSM-12, ZSM-22, ZSM-23, ZSM-35, and ZSM-48; and
(ii) at least 0.005 wt. % of the dehydrogenation component; the dehydrogenation components comprising one or more of Ga, Zn, Cu, Re, Mo, W, La, Fe, Ag, Pt, and Pd.

8. The process of claim 7 , wherein
(i) the dehydrocyclization catalyst comprises at least 90 wt. % of the molecular sieve component and at least 1 wt. % of the dehydrogenation component;
(ii) the molecular sieve component comprises at least 90 wt. % of (A) ZSM-5and/or (B) ZSM-12;
(iii) the first dehydrogenation component comprises ≥90 wt. % of (A) Ga and/or (B) Zn;
(iv) the reaction achieves (A) a C 2+ hydrocarbon conversion of X wt. % and (B) a methane selectivity of Y wt. %; and
(v) when (A)X>60 then Y≤40,(B)X is in the range of 50 to 60 then Y≤20, and (C) X<50 then Y≤15.

9. The process of claim 1 , wherein
(i) the reaction zone further comprises at least one pre-oxidized solid oxygen carrier (SOC);
(ii) step (d) further comprises 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; and
(iii) step (e) further comprises re-oxidizing the SOC with a third portion of the oxidant flow.

10. A hydrocarbon conversion process, comprising:
(a) providing a feed comprising C 2+ non-aromatic hydrocarbon;
(b) providing an oxidant and a gaseous fuel, the fuel and oxidant having a characteristic molar ratio M c 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

Assignees

• Exxonmobil Chemical Patents Inc

Inventors

• Keusenkothen Paul F
• Buchanan John S
• Coleman John S
• Washburn Seth M

Classifications

• C07C2529/70

  of types characterised by their specific structure not provided for in groups C07C2529/08 - C07C2529/65 · CPC title

• B01J2208/00548

  Flow · CPC title

• C07C2/76 Primary

  by condensation of hydrocarbons with partial elimination of hydrogen · CPC title

• C10G11/00

  Catalytic cracking, in the absence of hydrogen, of hydrocarbon oils (cracking in direct contact with molten metals or salts C10G9/34) · CPC title

• B01J8/0278

  Feeding reactive fluids (for solid material B01J8/0015) · CPC title