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US 9,353,023 B2Granted
Catalytic alkane conversion and olefin separation
AssigneeExxonMobil Chemical Patents Inc.
InventorsJuan D. Henao, Paul F. Keusenkothen, Abhimanyu O. Patil
Life of this patent
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Abstract
Disclosed is a hydrocarbon conversion process that is less energy intensive than comparable processes. The hydrocarbon conversion process is particularly desirable for converting alkanes, such as methane into C2+ olefins, such as ethylene and propylene, particularly with increasing selectivity to ethylene production. It is also desirable for effectively removing a C2 composition (i.e., ethane, ethylene and/or acetylene) produced from the catalytic conversion of hydrocarbon comprised of C2+ olefins. In addition, the hydrocarbon process is desirable for providing a substantially non-cryogenic separation of the desired C2 compositions from the hydrocarbons (e.g., methane) present in the reaction mixture.
Claims8
A process for producing and isolating a C2 composition comprising:
- (a) providing first and second hydrocarbon reactants and first and second oxidants, wherein the first and second hydrocarbon reactants each comprise ≧10% methane (molar basis, per mole of hydrocarbon reactant) and the first and second oxidants each comprise O2;
- (b) catalytically converting at least a portion of the first hydrocarbon reactant in the presence of the first oxidant and an oxidative methane coupling catalyst to produce a first reaction mixture comprised of (A) a C2 composition produced by the catalytic conversion, (B) water and/or CO2 produced during the catalytic conversion, and (C) unconverted methane, wherein
- i) the catalytic conversion includes catalytic oxidative methane coupling carried out in a reverse-flow reactor, the reverse-flow reactor comprising a heated first thermal mass comprising ≧50.0 wt. % of a first sorbent, based on total weight of the first thermal mass, a second thermal mass comprising ≧50.0 wt. % of a second sorbent, based on total weight of the second thermal mass, and the oxidative methane coupling catalyst;
- ii) the first reaction mixture is produced by combining the first hydrocarbon reactant and the first oxidant at a methane:O2 molar ratio of >2:1, and
- iii) the catalytic conversion is carried out in a first time interval, and the first interval includes the steps of:
- I passing the first hydrocarbon reactant and the first oxidant to the reverse-flow reactor;
- II transferring heat from the heated first thermal mass to at least one of the first hydrocarbon reactant and the first oxidant and combining the hydrocarbon reactant and the first oxidant to produce a first heated feedstock mixture;
- III producing the first reaction mixture by carrying out step (b) using the first hydrocarbon reactant and the first oxidant of the first heated feedstock mixture;
- IV transferring heat from the first reaction mixture to the second thermal mass to produce a heated second thermal mass;
- (c) exposing the first reaction mixture to the second sorbent under kinetic sorption conditions to selectively remove from the first reaction mixture at least a portion of the first reaction mixture's C2 composition to produce a first C2 lean mixture comprised of at least a portion of the unconverted methane, wherein
- (i) the first C2 lean mixture has a C2 content less than that of the first reaction mixture, and
- (ii) the sorbent comprises C2 selective sorbent having a selectivity for [ethane+ethylene] over that of methane >1.0;
- and
- (d) lessening or discontinuing the passing of the first hydrocarbon reactant and the first oxidant to the reverse-flow reactor.
11 more elements
A hydrocarbon conversion process, comprising:
- a. providing a first reactant and a first oxidant, wherein the first reactant comprises ≧10.0% C5− alkane (molar basis, per mole of first reactant) and the first oxidant comprises O2;
- b. providing a second reactant and a second oxidant, wherein the second reactant comprises ≧10.0% C5− alkane (molar basis, per mole of second reactant) and the second oxidant comprises O2;
- c. providing a reverse-flow reactor comprising a heated first thermal mass comprising ≧50.0 wt. % of a first sorbent, based on total weight of the first thermal mass, a second thermal mass comprising ≧50.0 wt. % of a second sorbent, based on total weight of the second thermal mass, and at least one oxidative methane coupling catalyst;
- d. during a first time interval,
- i. passing the first reactant and the first oxidant to the reverse-flow reactor;
- ii. transferring heat from the heated first thermal mass to at least one of the first reactant or first oxidant and combining the first reactant and first oxidant to produce a first feedstock mixture, the first feedstock mixture having a methane:O2 molar ratio ≧2.0;
- iii. catalytically converting at least a portion of the first feedstock's mixture's C5− alkane in the presence of the oxidative methane coupling catalyst to produce a first reaction mixture, the first reaction mixture comprising (A) ethylene produced by the alkane conversion and (B) unconverted C5− alkane, wherein the catalytic conversion includes catalytic oxidative methane coupling;
- iv. transferring heat from the first reaction mixture to the second thermal mass;
- v. exposing the first reaction mixture to the second sorbent to selectively sorb ethylene from the first reaction mixture to produce a first ethylene-lean mixture, wherein
- (A) the first ethylene-lean mixture comprises at least a portion of the first reaction mixture's unconverted C5− alkane,
- (B) the first ethylene-lean mixture has an ethylene content less than that of the first reaction mixture;
- and
- (C) the second sorbent comprises olefin-selective sorbent;
- and
- vi. lessening or discontinuing the passing of the first mixture to the reverse-flow reactor;
- and
- e. during a second time interval,
- i. passing the second reactant and second oxidant to the reverse-flow reactor;
- ii. transferring heat from the heated second thermal mass to at least one of the second reactant or second oxidant and combining the second reactant and second oxidant to produce a second feedstock mixture, the second feedstock mixture having a methane:O2 molar ratio ≧2.0;
- iii. catalytically converting at least a portion of the second feedstock mixture's methane in the presence of the oxidative methane coupling catalyst to produce a second reaction mixture, the second reaction mixture comprising (A) ethylene produced by the catalytic conversion and (B) unconverted C2 composition, wherein the catalytic conversion includes catalytic oxidative methane coupling;
- iv. transferring heat from the second reaction mixture to the first thermal mass to re-heat the first thermal mass;
- v. exposing the second reaction mixture under kinetic sorption conditions to the first sorbent to selectively sorb ethylene from the second reaction mixture to produce an ethylene-lean mixture, wherein
- (A) the second ethylene-lean mixture comprises at least a portion of the second reaction mixture's unconverted C5− alkane,
- (B) the second ethylene-lean mixture has an ethylene content less than that of the second reaction mixture;
- and
- (C) the first sorbent comprises olefin-selective sorbent;
- and
- vi. lessening or discontinuing the passing of the second mixture to the reverse-flow reactor.
25 more elements
Dependencies are inferred from the claim text.