WO2017141143A1

WO2017141143A1 - Conversion of methane steam reforming gas composition with co2 for the production of syngas composition for oxosynthesis

Info

Publication number: WO2017141143A1
Application number: PCT/IB2017/050740
Authority: WO
Inventors: Aghaddin Mamedov; Clark Rea
Original assignee: Sabic Global Technologies B.V.
Priority date: 2016-02-16
Filing date: 2017-02-10
Publication date: 2017-08-24

Abstract

Methods of preparing syngas are provided. Blend gas obtained from methane steam reforming can be reacted with CO2 in the presence of a spent catalyst to provide syngas with a composition ideal for oxo-synthesis.

Description

CONVERSION OF METHANE STEAM REFORMING GAS COMPOSITION WITH C0₂ FOR THE PRODUCTION OF SYNGAS COMPOSITION FOR OXO-

SYNTHESIS

CROSS-REFERENCE TO RELATED APPLICATIONS [0001] This application claims the benefit of priority of U.S. Provisional Patent Application No. 62/295,584, filed February 16, 2016, which is hereby incorporated by reference in its entirety.

FIELD

[0002] The presently disclosed subject matter relates to methods for production of synthesis gas with a composition ideal for oxo-synthesis.

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 the water shift reaction, thereby creating an overall product blend gas composition that includes C0₂, H₂, and CO. The water shift reaction can be described by the following equation:

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, aldehydes and methanol, from syngas can depend on the composition of the syngas. Syngas containing H₂ and CO in a molar ratio (H₂:CO) of about 1 : 1 can be useful for producing aldehydes and alcohols, e.g., oxo-synthesis, whereas a molar ratio of more than 4.5 : 1 can be useful for methanol synthesis. Syngas produced by methane steam reforming is typically suitable only for methanol synthesis. In order to use syngas produced by methane steam reforming for applications such as oxo-synthesis, the molar ratio of H₂ and CO must be adjusted to closer to stoichiometric.

[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 processes can further include forming hydrogenation reaction products with a catalyst at from about 500°C to about 900°C. The catalyst can include a spent chromia-alumina catalyst. The processes can also include recovering hydrogenation reaction products H₂ and CO in a ratio of from about 2: 1 to about 1 :2.

[0007] In certain embodiments, 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.

[0008] In certain embodiments, the blend gas comprises about 14.2% CO, about 8.1% C0₂ and about 78.2% H₂ or 21.1%CO, about 18.1%C0₂, and about 59.8%H₂.

[0009] In certain embodiments, the reaction temperature is about 600 °C.

[0010] In certain embodiments, the spent chromia-alumina catalyst comprises 60% catalyst and 40% inert ceramic particles.

[0011] In certain embodiments, the product mixture can include H₂ and CO in a molar ratio (H₂:CO) of about 1 : 1 or about less than 1 : 1.

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

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

[0014] In certain embodiments, C0₂ is present in a flow rate amount of from about 5 to about 3000 cc/min. In certain embodiments, C0₂ is present in a flow rate amount of from about 30 to about 200 cc/min.

[0015] In certain embodiments, the blend gas is present in a flow rate amount of from about 5 cc/min to about 3000 cc/min. In certain embodiments, the blend gas is present in a flow rate from about 30 cc/min to about 200 cc/min.

[0016] In certain embodiments, C0₂ and blend gas is present in a ratio of about 1 : 1.

[0017] The presently disclosed subject matter also 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 processes can further include forming hydrogenation reaction products with a catalyst at from about 500°C to about 900°C. The catalyst can include a spent chromia-alumina catalyst. The processes can also include recovering hydrogenation reaction products H₂ and CO in a ratio of about 1 : 1. The processes can also include contacting the H₂ and CO with a second catalyst and an olefin stream to form oxo- synthesis products.

BRIEF DESCRIPTION OF THE DRAWINGS

[0018] FIG. 1 is a schematic diagram presenting an exemplary process for preparation of syngas.

DETAILED DESCRIPTION

[0019] There remains a need in the art for new methods of preparing syngas with different ratios of H₂:CO, e.g., ratios close to 1 : 1. The presently disclosed subject matter provides novel methods and catalysts for converting C0₂ and a blend gas mixture into syngas with H₂:CO ratios close to 1 : 1. The presently disclosed subject matter includes the surprising discovery that syngas obtained from methane steam reforming processes can be reacted with C0₂ in the presence of a spent chromia-alumina catalyst to achieve a ratio of H₂:CO close to 1 : 1 in a product mixture.

[0020] 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

[0021] The methods of the present disclosure can involve fixed bed isothermal 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 900°C. Non-limiting examples of such materials can include quartz, metals, alloys (including steel), glasses, ceramics or glass lined metals, and coated metals.

[0022] 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.

[0023] In certain embodiments, reaction conditions within the reaction chamber can be isothermal. That is, hydrogenation of C0₂ can be conducted under isothermal conditions.

[0024] 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

[0025] Catalysts suitable for use in conjunction with the presently disclosed matter can be catalysts capable of catalyzing hydrogenation of C0₂. More specifically, a suitable catalyst shows high reaction rates, high olefin selectivity and has a longer stability.

[0026] In certain embodiments, the catalyst can be a metal oxide or mixed metal oxide. In specific embodiments, the catalyst can include one or more transition metals. More specifically, the catalyst can include chromium (Cr).

[0027] In certain embodiments, the catalyst can be a solid catalyst, e.g., a solid-supported catalyst. The 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.

[0028] In certain embodiments, the solid support can include zirconia (zirconium oxide), alumina (aluminum oxide), magnesia (magnesium oxide), SAPO-34 (silicoaluminophosphate) compositions, zeolites, and combinations 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.

[0029] In certain embodiments, the catalyst can include about 1% to about 25% Cr, 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% Cr by weight. The remainder of the catalyst can be solid support (e.g., A1₂0₃).

[0030] In specific embodiments, the catalyst is a Catofin® catalyst (Clariant). In certain embodiments, the catalyst is a spent Catofin® catalyst. In one, non-limiting embodiment, the spent catalyst can include 60% catalyst and 40% inert ceramic particles. In certain embodiments, the spent catalyst is the catalyst which was deactivated in an industrial isobutene dehydrogenation process. As used herein, a Catofin® catalyst is a chromia- alumina catalyst (CrOx/Al₂0₃) with an alkaline promotor.

[0031] A promotor can be selected from the group consisting of alkaline earth metals, lithium, sodium, potassium, rubidium, cesium, beryllium, magnesium, calcium, strontium, barium, tin, platinum-tin, zinc, copper, molybdenum, ruthenium, lanthanum and a combination thereof. [0032] Other catalysts suitable for dehydrogenation of light alkanes to light olefins are also contemplated by the presently disclosed subject matter. Dehydration catalysts include chromium oxide support catalysts with promotors as discussed, platinum supported catalysts with one or more promotors and one or more Group VIII metals (i.e., iron (Fe), ruthenium (Ru), osmium (Os) and hassium (Hs)), vanadium oxide catalysts, molybdenum oxide catalysts, gallium supported catalysts, and carbon-based catalysts (e.g., carbon nanotubes and nanofibers).

Reaction Mixtures

[0033] 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."

[0034] 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.

[0035] 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 21.1%CO + 18.1%C0₂+ 59.8%H₂. Methods of Preparing Syngas

[0036] The methods of the presently disclosed subject matter include methods of preparing syngas. In one embodiment, with reference to FIG. 1, 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 spent Cr/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 the catalyst at from about 500°C to about 900°C 102. The method can also include recovering hydrogenation reaction products H₂ and CO in a ratio of from about 2: 1 to about 1 :2 103. In further embodiments, the hydrogenation reaction products can undergo oxo- synthesis in the presence of a second catalyst and an olefin stream to produce alcohols and/or aldehydes.

[0037] 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 3000 cc/min. In certain embodiments, the flow rate can be from about 50 cc/min to about 200 cc/min. In certain embodiments, the flow rate can be about 32, 64, 96, 128, or 192 cc/min. In certain embodiments, the flow rate of the C0₂ can be from about 5 cc/min to about 3000 cc/min. In certain embodiments, the flow rate can be from about 50 cc/min to about 200 cc/min. In certain embodiments, the flow rate can be about 32, 64, 96, 128, or 192 cc/min.

[0038] In certain embodiments, the ratio of C0₂:blend gas in the reaction mixture is from about 3 : 1 to about 1 :3. In other embodiments, the ratio of C0₂:blend gas in the reaction mixture is about 1 : 1, about 1.5: 1, or about 0.8: 1.

[0039] 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 280 to about 400 h-1. [0040] 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 20 mL. In certain embodiments, the catalyst is present in an amount of about 15 ml.

[0041] 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 between about 500 °C and about 900 °C. In certain embodiments, the reaction temperature can be about 600 °C.

[0042] In certain embodiments, the product mixture can include H₂ and CO in a molar ratio (H₂:CO) of about 0.1 :3 to about 3 :0.1. In certain embodiments, the product mixture can include H₂ and CO in a molar ratio (H₂:CO) of from about 0.5:2 to about 2:0.5, e.g., about 0.5:2, 0.6:2, 0.7:2, 0.8:2, 0.9:2, 1 :2, 1.1 :2, 1.2:2, 1.3 :2, 1.4:2, 1.5:2, 1.6:2, 1.7:2, 1.8:2, or 1.9:2. In certain embodiments, the product mixture can include H₂ and CO in a molar ratio (H₂:CO) of about 1 : 1.

[0043] 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 in the presence of a spent chromia-alumina catalyst. Use of a spent chromia-alumina catalyst can result in H₂:CO ratios of about 1 : 1, ideal for use in oxo- synthesis. EXAMPLES

[0044] 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

[0045] A quartz reactor was charged with 15 ml of a spent Catofin® catalyst (Clariant; fixed bed Cr/alumina catalyst), comprising 60% catalyst and 40% inert ceramic particles. The reactor temperature was 600 °C. The catalyst particle size was 3x7 mm. A reaction mixture containing 2\ . \%CO + 18.1%C0₂+ 59.8%H₂ at a flow rate of 32 cc/min and a stream of C0₂ at a flow rate of 32 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 composition of the dry gas mixture after the reaction is presented in Table 1.

Table 1. Composition of dry gas (mol %)

EXAMPLE 2 - Hydrogenation of CO? at alternative flow rates

[0046] The process of Example 1 was repeated with a change in flow rate. The blend gas was fed into the reactor at 64 cc/min and C0₂ at 64 cc/min. The composition of the dry gas mixture after the reaction is presented in Table 2. Table 2. Composition of dry gas (mol %)

EXAMPLE 3 - Hydrogenation of CO? at alternative flow rates

[0047] The process of Example 1 was repeated with a change in flow rate. The blend gas was fed into the reactor at 96 cc/min and C0₂ at 96 cc/min. The composition of the dry gas mixture after the reaction is presented in Table 3.

Table 3. Composition of dry gas (mol %)

EXAMPLE 4 - Hydrogenation of CO? at alternative flow rates

[0048] The process of Example 1 was repeated with a change in flow rate. The blend gas was fed into the reactor at 128 cc/min and C0₂ at 128 cc/min. The composition of the dry gas mixture after the reaction is presented in Table 4.

Table 4. Composition of dry gas (mol %)

EXAMPLE 5 - Hydrogenation of CO? at alternative flow rates

[0049] The process of Example 1 was repeated with a change in flow rate. The blend gas was fed into the reactor at 192 cc/min and C0₂ at 192 cc/min. The composition of the dry gas mixture after the reaction is presented in Table 5.

Table 5. Composition of dry gas (mol %)

* * *

[0050] 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; and

b. contacting the blend gas and C0₂ with a spent chromia-alumina catalyst at from about 500°C to about 900°C to form a product mixture comprising H₂ and CO in a ratio of from about 2: 1 to about 1 :2.

2. 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.

3. The process of claim 2, wherein the blend gas comprises about 14.2% CO, about 8.1% C0₂ and about 78.2% H₂.

4. The process of claim 2, wherein the blend gas comprises about 21.1% CO, about 18.1% C0_2, and about 59.8% H₂.

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

6. The process of claim 1, wherein the spent chromia-alumina catalyst comprises 60% catalyst and 40% inert ceramic particles.

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

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

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

10. The process of claim 1, wherein the reactor is a quartz reactor.

1 1. The process of claim 1, wherein C0₂ is present in a flow rate amount of from about 5 to about 3000 cc/min.

12. The process of claim 1 1, wherein C0₂ is present in a flow rate amount of from about 30 to about 200 cc/min.

13. The process of claim 1, wherein the blend gas is present in a flow rate amount of from about 5 cc/min to about 3000 cc/min.

14. The process of claim 13, wherein the blend gas is present in a flow rate from about 30 cc/min to about 200 cc/min.

15. The process of claim 1, wherein C0₂ and blend gas is present in a ratio of about 1 : 1 in step a).

16. The process of claim 1, wherein the blend gas is obtained from a methane steam

reforming reaction.

17. The process of claim 16, wherein the product mixture comprises H₂ and CO in a

molar ratio (H₂:CO) of about 1 : 1.

18. 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. contacting the blend gas and C0₂ with a spent chromia-alumina catalyst at from about 500°C to about 900°C to form a product mixture comprising H₂ and CO in a ratio of about 1 : 1; and

c. contacting the product mixture with a second catalyst and an olefin stream to form oxo-synthesis products.

19. The process of claim 18, wherein the blend gas is obtained from a methane steam

reforming reaction.