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1. WO2020142487 - METHANOL PRODUCTION PROCESS

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[ EN ]

CLAIMS

What is claimed is:

1. A process for producing methanol comprising:

(a) reacting under near-isothermal conditions, via a catalytic partial oxidation (CPO) reaction, a CPO reactant mixture in a CPO reactor to produce syngas; wherein the CPO reactant mixture comprises hydrocarbons and oxygen; wherein the CPO reactor comprises a CPO catalyst; wherein the syngas comprises hydrogen, carbon monoxide, carbon dioxide, water, and unreacted hydrocarbons; and wherein the near-isothermal conditions comprise a temperature variation of less than about + 100 °C across the CPO reactor and/or a catalyst bed thereof, and wherein the catalyst bed comprises the CPO catalyst;

(b) introducing at least a portion of the syngas to a methanol reactor to produce a methanol reactor effluent stream; wherein the methanol reactor effluent stream comprises methanol, water, hydrogen, carbon monoxide, carbon dioxide, and hydrocarbons; and

(c) separating at least a portion of the methanol reactor effluent stream into a crude methanol stream and a vapor stream; wherein the crude methanol stream comprises methanol and water; wherein the vapor stream comprises hydrogen, carbon monoxide, carbon dioxide, and hydrocarbons; and wherein the crude methanol stream comprises water in an amount of less than about 10 wt.%, based on the total weight of the crude methanol stream.

2. The process of claim 1, wherein the near-isothermal conditions are provided by external heat exchange, external coolant fluid cooling, reactive cooling, liquid nitrogen cooling, cryogenic cooling, electric heating, electric arc heating, microwave heating, radiant heating, natural gas combustion, solar heating, infrared heating, use of a diluent in the CPO reactant mixture, or combinations thereof; and wherein the diluent comprises water, steam, inert gases, nitrogen, carbon dioxide, or combinations thereof.

3. The process of claim 2, wherein the diluent contributes to the near-isothermal conditions by phase change and/or reactive heat exchange.

4. The process of claims 1, wherein the near-isothermal conditions comprise and optionally at least one CPO operational parameter selected from the group consisting of a CPO feed temperature of from about 25 °C to about 600 °C; a CPO effluent temperature in the range of from about 600 °C to about 1,400 °C; a CPO pressure of from about 1 barg to about 90 barg; a CPO contact time of from about 0.001 milliseconds (ms) to about 5 s; a carbon to oxygen (C/O) molar ratio in the CPO reactant mixture of from about 0.5: 1 to about 3: 1, wherein the C/O molar ratio refers to the total moles of carbon (C) of hydrocarbons in the reactant mixture divided by the total moles of oxygen (02) in the reactant mixture; a steam to carbon (S/C) molar ratio in the CPO reactant mixture of from about 0.01 : 1 to less than about

2.4: 1, wherein the S/C molar ratio refers to the total moles of water (H20) in the reactant mixture divided by the total moles of carbon (C) of hydrocarbons in the reactant mixture; and combinations thereof.

5. The process of claim 4, wherein the CPO effluent temperature is in the range of from about 750 °C to about 1,150 °C.

6. The process of claim 1, wherein the near-isothermal conditions are provided by removal of process heat from the CPO reactor.

7. The process of claim 6, wherein the removal of heat comprises heat removal via an endothermic dry reforming reaction between carbon dioxide and methane.

8. The process of claim 6, wherein the removal of heat comprises heat removal via an endothermic reforming reaction between water and methane.

9. The process of claim 1, wherein a portion of the hydrocarbons in the CPO reactant mixture undergo decomposition to carbon and hydrogen, wherein at least a portion of the carbon reacts with carbon dioxide in the CPO reactor to produce carbon monoxide and/or wherein at least a portion of the carbon reacts with water in the CPO reactor to produce carbon monoxide and hydrogen.

10. The process of claim 1, wherein the syngas comprises carbon dioxide in an amount of from about 0.1 mol% to about 5 mol%.

11. The process of claim 1 , wherein the syngas is characterized by a carbon monoxide to carbon dioxide (CO/C02) molar ratio of equal to or greater than about 5.

12. The process of claim 1, wherein the hydrocarbons comprise methane, natural gas, natural gas liquids, associated gas, well head gas, enriched gas, paraffins, shale gas, shale liquids, fluid catalytic cracking (FCC) off gas, refinery process gases, stack gases, fuel gas from fuel gas header, or combinations thereof.

13. The process of claim 1, wherein the syngas is characterized by an M ratio of from about 1.6 to about 2.2, wherein the M ratio is a molar ratio defined as (H2-C02)/(C0+C02).

14. The process of claim 1, wherein the syngas is characterized by an M ratio that varies by less than about 20% from a target M ratio under the near-isothermal conditions for a given set of reactor operating conditions, and wherein the M ratio is a molar ratio defined as (H2-C02)/(C0+C02).

15. The process of claim 14, wherein the reactor operating conditions comprise a CPO pressure of less than about 30 barg; and/or a carbon to oxygen (C/O) molar ratio in the CPO reactant mixture of less than about 2.2: 1, wherein the C/O molar ratio refers to the total moles of carbon (C) of hydrocarbons in the reactant mixture divided by the total moles of oxygen (02) in the reactant mixture.

16. The process of claim 1 further comprising (i) separating at least a portion of the vapor stream into a hydrogen stream and a residual gas stream, wherein the hydrogen stream comprises at least a portion of the hydrogen of the vapor stream, and wherein the residual gas stream comprises carbon monoxide,

carbon dioxide, and hydrocarbons; and (ii) recycling at least a portion of the hydrogen stream to the methanol reactor.

17. The process of claim 1 further comprising separating at least a portion of the crude methanol stream in a distillation unit into a methanol stream and a water stream, wherein the distillation unit comprises one or more distillation columns.

18. A process for producing methanol comprising:

(a) reacting under near-isothermal conditions, via a catalytic partial oxidation (CPO) reaction, a CPO reactant mixture in a CPO reactor to produce syngas; wherein the CPO reactant mixture comprises hydrocarbons and oxygen; wherein the CPO reactor comprises a CPO catalyst; wherein the syngas comprises hydrogen, carbon monoxide, carbon dioxide, water, and unreacted hydrocarbons; wherein the syngas comprises carbon dioxide in an amount of from about 0.1 mol% to about 5 mol%; and wherein the near-isothermal conditions comprise a temperature variation of less than about + 100 °C across the CPO reactor and/or a catalyst bed thereof, and wherein the catalyst bed comprises the CPO catalyst;

(b) introducing at least a portion of the syngas to a methanol reactor to produce a methanol reactor effluent stream; wherein the methanol reactor effluent stream comprises methanol, water, hydrogen, carbon monoxide, carbon dioxide, and hydrocarbons;

(c) separating at least a portion of the methanol reactor effluent stream into a crude methanol stream and a vapor stream, wherein the crude methanol stream comprises methanol and water, wherein the vapor stream comprises hydrogen, carbon monoxide, carbon dioxide, and hydrocarbons; and wherein the crude methanol stream comprises water in an amount of less than about 5 wt.%, based on the total weight of the crude methanol stream;

(d) separating at least a portion of the crude methanol stream in a distillation unit into a methanol stream and a water stream, wherein the distillation unit comprises one or more distillation columns;

(e) separating at least a portion of the vapor stream into a hydrogen stream and a residual gas stream, wherein the hydrogen stream comprises at least a portion of the hydrogen of the vapor stream, and wherein the residual gas stream comprises carbon monoxide, carbon dioxide, and hydrocarbons; and

(f) recycling at least a portion of the hydrogen stream to the methanol reactor.

19. The process of claim 18, wherein a CPO effluent temperature is in the range of from about 850 °C to about 1,050 °C.

20. The process of claim 18, wherein the number of distillation columns is lower when compared to the number of distillation columns in an otherwise similar process that introduces to a methanol reactor a syngas comprising carbon dioxide in an amount of equal to or greater than about 5 mol%.