WO2017098390A1

WO2017098390A1 - Conversion of blend gas composition comprising methane steam reforming process with co2 for the production of syngas composition for multiple applications

Info

Publication number: WO2017098390A1
Application number: PCT/IB2016/057329
Authority: WO
Inventors: Aghaddin Mamedov; Clark Rea
Original assignee: Sabic Global Technologies B.V.
Priority date: 2015-12-09
Filing date: 2016-12-02
Publication date: 2017-06-15

Abstract

Methods of preparing syngas are provided. Blend gas obtained from methane steam reforming can be reacted with CO₂to provide syngas with various compositions.

Description

CONVERSION OF BLEND GAS COMPOSITION COMPRISING METHANE STEAM REFORMING PROCESS WITH C0₂ FOR THE PRODUCTION OF SYNGAS COMPOSITION FOR MULTIPLE APPLICATIONS

CROSS-REFERENCE TO RELATED APPLICATIONS [0001] This application claims priority to and the benefit of U.S. Provisional Application No. 62/265,083, filed December 9, 2015. The contents of the referenced application are incorporated into the present application by reference.

FIELD

[0002] The presently disclosed subject matter relates to methods for production of synthesis gas with various compositions.

BACKGROUND

[0003] Synthesis gas (also known as syngas) is a mixture of carbon monoxide (CO) and hydrogen (H₂). Syngas can be prepared in a number of different ways including through a reverse water gas shift (RWGS) reaction or methane steam reforming. The steam reforming reaction can be described by the following equation:

CH₄ + H₂0≠CO + 3H₂ (1) and occurs in the presence of a metal catalyst at high temperatures. The reaction can produce some amounts of C0₂ through water shift reaction, thereby creating an overall product blend gas:

CO+ H₂O^C0₂+ H₂0 (2)

[0004] Syngas is a versatile mixture that can be used to prepare light olefins, methanol, acetic acid, aldehydes, and many other important industrial chemicals. However, the efficiency of the preparation of different chemicals, for example, methanol versus light olefins, from syngas can depend on the composition of the syngas. Syngas containing H₂ and CO in a molar ratio (H₂:CO) of about 2: 1 can be useful for olefin synthesis whereas a molar ratio of more than 4.5: 1 can be useful for methanol synthesis. Syngas produced by methane steam reforming is suitable only for methanol synthesis. In order to use syngas produced by methane steam reforming for applications other than methanol synthesis, the syngas must be separated into its components and then mixed with additional H₂ and/or CO to achieve the necessary molar ratio.

[0005] Thus, there remains a need in the art for new methods for producing syngas with ideal molar ratios of H₂:CO for different synthesis applications.

SUMMARY OF THE DISCLOSED SUBJECT MATTER

[0006] The presently disclosed subject matter provides for processes for C0₂ hydrogenation, which can include feeding blend gas and C0₂ into a reactor. The blend gas can include CO, C0₂ and H₂. The process can further include forming hydrogenation reaction products with a catalyst at from about 580°C to about 640°C. The catalyst can include Cu-Mn/Al₂03. The process can also include recovering hydrogenation reaction products H₂ and CO in a ratio of from about 3 : 1 to about 1 :3.

[0007] In certain embodiments, the catalyst can include 10% Cu and 10% Mn by weight.

[0008] In certain embodiments, the blend gas can include from about 10 to about 20% CO, from about 5 to about 20% C0₂ and from about 60 to about 80% H₂.

[0009] In certain embodiments, the blend gas can include 14.2% CO, 8.1% C0₂ and 78.2% H₂ or 21.7%CO + 17.7%C0₂+ 60.4%H₂.

[0010] In certain embodiments, the reaction temperature is about 640 °C. In certain embodiments, the reaction temperature is about 600 °C. In certain embodiments, the reaction temperature is about 580 °C.

[0011] In certain embodiments, the product mixture can include H₂ and CO in a molar ratio (H₂:CO) of about 0.5: 1 to about 5: 1. In further embodiments, the product mixture can include H₂ and CO in a molar ratio (H₂:CO) of about 4.5: 1. In further embodiments, the product mixture can include H₂ and CO in a molar ratio (H₂:CO) of about 2: 1, about 1 : 1, or about 0.5: 1.

[0012] In further embodiments, the product mixture can further include C0₂ and H₂0.

[0013] In certain embodiments, the reactor is a quartz or metal reactor.

[0014] In certain embodiments, C0₂ is present in a flow rate amount of from about 5 to about 30 cc/min. In certain embodiments, C0₂ is present in a flow rate amount of about 15 cc/min.

[0015] In certain embodiments, the blend gas is present in a flow rate amount of from about 5 cc/min to about 50 cc/min. In certain embodiments, the blend gas is present in a flow rate from about 10 cc/min to about 35 cc/min.

[0016] In certain embodiments, the process proceeds at a gas hour space velocity (GHSV) of from about 360 to about 3600 h^"1.

BRIEF DESCRIPTION OF THE DRAWINGS

[0017] FIG. 1 is a schematic diagram presenting an exemplary process for preparation of syngas.

DETAILED DESCRIPTION

[0018] There remains a need in the art for new methods of preparing syngas with different ratios of H₂:CO. The presently disclosed subject matter provides novel methods of converting C0₂ and a blend gas mixture into syngas with various H₂:CO ratios. The presently disclosed subject matter includes the surprising discovery that syngas obtained from methane steam reforming processes can be reacted with C0₂ to control the ratio of H₂:CO in a product mixture.

[0019] As used herein, the term "about" or "approximately" means within an acceptable error range for the particular value as determined by one of ordinary skill in the art, which will depend in part on how the value is measured or determined, i.e., the limitations of the measurement system. For example, "about" can mean a range of up to 20%, up to 10%, up to 5%), and or up to 1% of a given value.

Reactors and Reaction Chambers

[0020] The methods of the present disclosure can involve fixed bed isothermal or adiabatic reactors suitable for reactions of gaseous reactants and reagents catalyzed by solid catalysts. The reactor can be constructed of any suitable materials capable of holding temperatures, for example from about 500°C to about 700°C. Non-limiting examples of such materials can include quartz, metals, alloys (including steel), glasses, ceramics or glass lined metals, and coated metals.

[0021] The dimensions of the reaction vessel and reaction chamber are variable and can depend on the production capacity, feed volume, and catalyst. The geometries of the reactor can be adjustable in various ways known to one of ordinary skill in the art.

[0022] In certain embodiments, reaction conditions within the reaction chamber can be isothermal. That is, hydrogenation of C0₂ can be conducted under isothermal conditions. In certain alternative embodiments, a temperature gradient can be established within the reaction chamber. For example, hydrogenation of C0₂ can be conducted across a temperature gradient using an adiabatic reactor.

[0023] The pressure within the reaction chamber can be varied, as is known in the art. In certain embodiments, the pressure within the reaction chamber can be atmospheric pressure, i.e., about 1 bar.

Catalysts

[0024] Catalysts suitable for use in conjunction with the presently disclosed subject matter can be catalysts capable of catalyzing hydrogenation of C0₂. In certain embodiments, the catalyst can be a solid catalyst, e.g., a solid-supported catalyst. The catalyst can be a metal oxide or mixed metal oxide. In certain embodiments, the catalyst can be located in a fixed packed bed, i.e., a catalyst fixed bed. In certain embodiments, the catalyst can include solid pellets, granules, plates, tablets, or rings.

[0025] In certain embodiments, the catalyst can include one or more transition metals. The catalyst can include copper (Cu) and/or manganese (Mn).

[0026] In certain embodiments, the catalyst can include a solid support. That is, the catalyst can be solid-supported. In certain embodiments, the solid support can include various metal salts, metalloid oxides, and/or metal oxides, e.g., titania (titanium oxide), zirconia (zirconium oxide), silica (silicon oxide), alumina (aluminum oxide), magnesia (magnesium oxide), and magnesium chloride. In certain embodiments, the solid support can include alumina (A1₂0₃), silica (Si0₂), magnesia (MgO), titania (Ti0₂), zirconia (Zr0₂), cerium(IV) oxide (Ce0₂), or a combination thereof. The amount of the solid support present in the catalyst can be between about 15% and about 95%, by weight, relative to the total weight of the catalyst. By way of non-limiting example, the solid support can constitute about 15%, 20%, 25%, 30%, 35%, 40%, 45%, 50%, 55%, 60%, 65%, 70%, 75%, 80%, 85%, 90%, or 95% of the total weight of the catalyst.

[0027] In certain embodiments, the catalyst can include about 1% to about 25% Cu and/or Mn, by weight. For example, the catalyst can include about 1%, 2%, 3%, 4%, 5%, 6%, 7%, 8%, 9%, 10%, 11%, 12%, 13%, 14%, 15%, 16%, 17%, 18%, 20%, 22%, or 25% Cu and/or Mn, by weight. The remainder of the catalyst can be solid support {e.g., A1₂0₃). In certain embodiments, the catalyst includes about 10% Cu and 10% Mn supported on A1₂0₃.

[0028] The catalysts of the presently disclosed subject matter can be prepared according to various techniques known in the art. For example, metal oxide catalysts suitable for use in hydrogenation reactions can be prepared from various metal nitrates, metal halides, metal salts of organic acids, metal hydroxides, metal carbonates, metal oxyhalides, metal sulfates, and the like. In certain embodiments, a transition metal oxide (e.g., a Mn oxide) can be precipitated along with a solid support (e.g., AI₂O₃).

Reaction Mixtures

[0029] The presently disclosed subject matter provides methods of converting H₂ within a blend gas mixture and C0₂ into syngas. Blend gas can include a mixture of CO, C0₂, and H₂. A mixture of blend gas and C0₂ can be termed a "reaction mixture." The mixture of blend gas and C0₂ can alternatively be termed a "feed mixture" or "feed gas."

[0030] The C0₂ in the reaction mixture can be derived from various sources. In certain embodiments, the C0₂ can be a waste product from an industrial process. In certain embodiments, C0₂ that remains unreacted can be recovered and recycled back into the reaction.

[0031] Reaction mixtures suitable for use with the presently disclosed methods can include various proportions of blend gas. In certain embodiments, the blend gas is obtained from a methane steam reforming process. In other embodiments, the blend gas is obtained from a C0₂ injected methane steam reforming process. In certain embodiments, the blend gas can include from about 5% to about 25% CO. In other embodiments, the blend gas can include from about 5% to about 25% C0₂. In additional embodiments, the blend gas can include from about 50% to 90% H₂. In certain embodiments, the reaction mixture can include a blend gas comprising 14.2%CO + 8.1%C0₂+ 78.2%H₂ or 21.7%CO + 17.7%C0₂+ 60.4%H₂. Methods of Preparing Syngas

[0032] The methods of the presently disclosed subject matter include methods of preparing syngas. In one embodiment, an exemplary method 100 can include providing a reaction chamber, as described above. The reaction chamber can include a solid-supported catalyst, e.g. a Cu-Mn/Al₂03 catalyst as described above. The method can further include feeding blend gas and C0₂ into a reactor, wherein the blend gas includes CO, C0₂ and H₂ 101. The method can additionally include forming hydrogenation reaction products with a catalyst at from about 580°C to about 640°C 102. The method can also include recovering hydrogenation reaction products H₂ and CO in a ratio of from about 3 : 1 to about 1 :3 103.

[0033] The reaction mixture can be fed into the reaction chamber at various flow rates. The flow rate can be varied for each component of the reaction mixture, e.g., blend gas and C0₂, as is known in the art. In certain embodiments, the flow rate of the blend mixture can be from about 5 cc/min to about 50 cc/min. In certain embodiments, the flow rate can be from about 10 cc/min to about 35 cc/min. In certain embodiments, the flow rate can be about 11, 12, 15, 26.7, or 34 cc/min. In certain embodiments, the flow rate of the C0₂ can be from about 5 cc/min to about 30 cc/min. In certain embodiments, the flow rate can be from about 5 cc/min to about 20 cc/min. In certain embodiments, the flow rate can be about 6.7, 8.5, 15, 18, or 19 cc/min. In certain embodiments, the flow rate of the components of the reaction and total gas mixture can be selected to provide gas hour space velocity (GHSV) from about 360 to about 3600 h^"1. In certain embodiments, the GHSV can be from about 350 to about 500 h^"1 or from about 800 to about 1200 h^"1. In other embodiments, the GHSV can be about 1000 h^"1.

[0034] In certain embodiments, the catalyst is present in an amount of from about 1 to about 1000 mL. In certain embodiments, the catalyst is present in an amount of from about 2 to about 10 mL. In certain embodiments, the catalyst is present in an amount of about 2 or 8 mL.

[0035] The reaction temperature can be understood to be the temperature within the reaction chamber. The reaction temperature can influence the hydrogenation reaction, including conversion of C0₂ and H₂, the ratio of H₂:CO in the product mixture, and the overall yield. In certain embodiments, the reaction temperature can be greater than 560 °C, e.g., greater than about 570 °C, 580 °C, 590 °C, 600 °C. In certain embodiments, the reaction temperature can be less than about 650 °C, e.g., less than about 640 °C, 630 °C, 620 °C, 610 °C, and 600°C. In certain embodiments, the reaction temperature can be between about 580 °C and about 640 °C. In certain embodiments, the reaction temperature can be about 640 °C. In certain embodiments, the reaction temperature can be about 600 °C. In certain embodiments, the reaction temperature can be about 580 °C.

[0036] The reaction can proceed with partial conversion of C0₂ and H₂, thus providing a product mixture that includes CO, H₂0, C0₂, and H₂. In certain embodiments, the reaction can be performed to about 70% conversion of C0₂.

[0037] In certain embodiments, the product mixture can include H₂ and CO in a molar ratio (H₂:CO) of about 0.5: 1 to about 5: 1. In certain embodiments, the product mixture can include H₂ and CO in a molar ratio (H₂:CO) of about 1 : 1 to about 3 : 1, e.g., about 1 : 1, 1.1 : 1, 1.2: 1, 1.3 : 1, 1.4: 1, 1.5: 1, 1.6: 1, 1.7: 1, 1.8: 1, 1.9: 1, 2: 1, 2.1 : 1, 2.2: 1, 2.3 : 1, 2.4: 1, 2.5: 1, 2.6: 1, 2.7: 1, 2.8: 1, 2.9: 1, or 3 : 1. In certain embodiments, the product mixture can include H₂ and CO in a molar ratio (H₂:CO) of about 1.25, about 1.07, about 0.94, about 2.4, about 2.27, about 1.54, about 1.48, or about 0.9.

[0038] The methods of the presently disclosed subject matter can have advantages over other techniques for preparation of syngas from methane steam reforming gas. The presently disclosed subject matter includes the surprising discovery that the syngas composition can be varied by conversion with C0₂. Varying the initial blend gas composition and C0₂ can result in various H₂:CO ratios, ideal for applications in addition to methanol synthesis. EXAMPLES

[0039] The following examples are merely illustrative of the presently disclosed subject matter and should not be considered as limiting in any way.

EXAMPLE 1 - Hydrogenation of CO? with blend gas

[0040] A quartz reactor was charged with 8 ml (5.18g) of a 10%Cu- 10%Mn/Al₂O₃ catalyst. The reactor temperature was 600 °C. A reaction mixture containing 14.2%CO + 8.1%C0₂+ 78.2%H₂ at a flow rate of 15 cc/min and a stream of C0₂ at a flow rate of 15 cc/min was fed into the reactor, thereby contacting the reaction mixture with the catalyst and inducing a hydrogenation reaction. A product mixture containing H₂, C0₂, and CO was removed from the reactor. The ratio of H₂:CO of the dry gas was 1.25. Conversion of C0₂ was 37.9%. The composition of the dry gas mixture is presented in Table 1.

Table 1. Composition of dry gas

EXAMPLE 2 - Hydrogenation of CO? with blend gas

[0041] The process of Example 1 was repeated with a change in flow rate. The blend gas was fed into the reactor at 12 cc/min and C0₂ at 18 cc/min. The ratio of H₂:CO of the dry gas was 1.07. Conversion of C0₂ was 30.4%. The composition of the dry gas mixture is presented in Table 2. Table 2. Composition of dry gas

EXAMPLE 3 - Hydrogenation of CO? with blend gas

[0042] The process of Example 1 was repeated with a change in flow rate. The blend gas was fed into the reactor at 11 cc/min and C0₂ at 19 cc/min The ratio of H₂:CO of the dry gas was 0.94. Conversion of C0₂ was 27.8%. The composition of the dry gas mixture is presented in Table 3.

Table 3. Composition of dry gas

EXAMPLE 4 - Hydrogenation of CO? with blend gas

[0043] The process of Example 1 was repeated with a change in flow rate in a metal reactor. The blend gas was fed into the reactor at 34 cc/min and C0₂ at 8.5 cc/min The ratio of H₂:CO of the dry gas was 2.4. Conversion of C0₂ was 58.8%. The composition of the dry gas mixture is presented in Table 4.

Table 4. Composition of dry gas

EXAMPLE 5 - Hydrogenation of CO? with blend gas

[0044] The process of Example 1 was repeated in a metal reactor. Reaction temperature was 640°C and catalyst loading was 2 ml. The blend gas was fed into the reactor at 34 cc/min and C0₂ at 8.5 cc/min. The ratio of H₂:CO of the dry gas was 2.27. Conversion of C0₂ was 61.1%. The composition of the dry gas mixture is presented in Table 5.

Table 5. Composition of dry gas

EXAMPLE 6 - Hydrogenation of CO? with blend gas

[0045] A metal reactor was charged with 2 ml of a 10%Cu-10%Mn/Al₂O₃ catalyst. The reactor temperature was 580 °C. A reaction mixture containing 21.7%CO + 17.7%C0₂+ 60.4%H₂ at a flow rate of 26.7 cc/min and a stream of C0₂ at a flow rate of 6.7 cc/min were fed into the reactor, thereby contacting the reaction mixture with the catalyst and inducing a hydrogenation reaction. A product mixture containing H₂, C0₂, CO, and CH₄ was removed from the reactor. The ratio of H₂:CO of the dry gas was 1.54. Conversion of C0₂ was 52.4%. The composition of the dry gas mixture is presented in Table 6.

Table 6. Composition of dry gas

EXAMPLE 7 - Hydrogenation of CO? with blend gas

[0046] The reaction of Example 6 was repeated at a temperature of 600 °C. A product mixture containing H₂, C0₂, CO, and CH₄ was removed from the reactor. The ratio of H₂:CO of the dry gas was 1.48. Conversion of C0₂ was 53.7%. The composition of the dry gas mixture is presented in Table 7.

Table 7. Composition of dry gas

EXAMPLE 8 - Hydrogenation of CO? with blend gas

[0047] The reaction of Example 7 was repeated in a quartz reactor. The blend gas was fed into the reactor at 15 cc/min and C0₂ at 15 cc/min. A product mixture containing H₂, C0₂, CO, and CH₄ was removed from the reactor. The ratio of H₂:CO of the dry gas was 0.9. Conversion of C0₂ was 34.6%. The composition of the dry gas mixture is presented in Table 8.

Table 8. Composition of dry gas

[0048] Although the presently disclosed subject matter and its advantages have been described in detail, it should be understood that various changes, substitutions and alterations can be made herein without departing from the spirit and scope of the disclosed subject matter as defined by the appended claims. Moreover, the scope of the disclosed subject matter is not intended to be limited to the particular embodiments described in the specification. Accordingly, the appended claims are intended to include within their scope such alternatives.

Claims

1. A process for C0₂ hydrogenation, the process comprising:

a. feeding blend gas and C0₂ into a reactor, wherein the blend gas comprises CO, C0₂ and H₂;

b. forming hydrogenation reaction products with a catalyst at from about 580°C to about 640°C, wherein the catalyst is Cu-Mn/Al₂0₃; and

c. recovering hydrogenation reaction products H₂ and CO in a ratio of from

about 3 : 1 to about 1 :3 or about 0.5 : 1 to about 5 : 1.

2. The process of claim 1, wherein the catalyst comprises about 10% Cu by weight and about 10% Mn by weight.

3. The process of claim 1, wherein the blend gas comprises from about 10% to about 20% CO, from about 5% to about 20% C0₂ and from about 60% to about 80% H₂.

4. The process of claim 3, wherein the blend gas comprises about 14.2% CO, about 8.1% C0₂ and about 78.2% H₂.

5. The process of claim 1, wherein the blend gas comprises about 21.7%CO , about 17.7%C0_2; and about 60.4%H₂.

6. The process of claim 1, wherein the reaction temperature is about 640 °C.

7. The process of claim 1, wherein the reaction temperature is about 600 °C.

8. The process of claim 1, wherein the reaction temperature is about 580 °C.

9. The process of claim 1, wherein the product mixture comprises H₂ and CO in a molar ratio (H₂:CO) of about 0.5 : 1 to about 5 : 1.

10. The process of claim 9, wherein the product mixture comprises H₂ and CO in a molar ratio (H₂:CO) of about 4.5 : 1.

1 1. The process of claim 9, wherein the product mixture comprises H₂ and CO in a molar ratio (H₂:CO) of about 2: 1.

12. The process of claim 9, wherein the product mixture comprises H₂ and CO in a molar ratio (H₂:CO) of about 1 : 1.

13. The process of claim 9, wherein the product mixture comprises H₂ and CO in a molar ratio (H₂:CO) of about 0.5: 1.

14. The process of claim 1, wherein the product mixture further comprises C0₂ and H₂0.

15. The process of claim 1, wherein the reactor is a quartz or metal reactor.

16. The process of claim 1, wherein C0₂ is present in a flow rate amount of from about 5 to about 30 cc/min.

17. The process of claim 16, wherein C0₂ is present in a flow rate amount of about 15 cc/min.

18. The process of claim 1, wherein the blend gas is present in a flow rate amount of from about 5 cc/min to about 50 cc/min.

19. The process of claim 18, wherein the blend gas is present in a flow rate from about 10 cc/min to about 35 cc/min.

20. The process of claim 1, wherein the process proceeds at a gas hour space velocity (GHSV) of from about 360 to about 3600 h^"1.