Patent Application
20250073681
Carbon dioxide (CO2) can be converted to carbon monoxide (CO) through a process called reverse water gas shift reaction (RWGS). CO is a useful feedstock for methanol synthesis, liquid hydrocarbon production, and the production of other specialty chemicals. Typically, RWGS reactions are performed at low (ambient) pressure and high temperature. The RWGS reaction is usually conducted at ambient pressure since the methanation reaction (conversion of carbon oxides and hydrogen to methane) is favored at high-pressure. Also, the reaction must be conducted at high temperatures (above 500° C.) when a non-noble-metal catalyst is used.
This summary is provided to introduce a selection of concepts that are further described below in the detailed description. This summary is not intended to identify key or essential features of the claimed subject matter, nor is it intended to be used as an aid in limiting the scope of the claimed subject matter.
In one aspect, embodiments disclosed herein relate to a composition of an indium oxide catalyst comprising an alkali dopant.
Embodiments disclosed herein also relate to a method for producing an indium oxide catalyst including an alkali dopant, including the steps of: mixing a solution of an indium salt with a base to form precipitated indium hydroxide, contacting the precipitated indium hydroxide with a solution including an alkali metal salt to produce an indium hydroxide solution, and calcinating the indium hydroxide solution to form indium oxide; thereby forming the indium oxide catalyst including an alkali dopant.
Any combinations of the various embodiments and implementations disclosed herein can be used in a further embodiment, consistent with the disclosure. Other aspects and advantages of the claimed subject matter will be apparent from the following description and the appended claims.
In the following detailed description of embodiments of the disclosure, numerous specific details are set forth in order to provide a more thorough understanding of the disclosure. However, it will be apparent to one of ordinary skill in the art that the disclosure may be practiced without these specific details. In other instances, well-known features have not been described in detail to avoid unnecessarily complicating the description.
Throughout the application, ordinal numbers (e.g., first, second, third, etc.) may be used as an adjective for an element (i.e., any noun in the application). The use of ordinal numbers is not to imply or create any particular ordering of the elements nor to limit any element to being only a single element unless expressly disclosed, such as using the terms “before”, “after”, “single”, and other such terminology. Rather, the use of ordinal numbers is to distinguish between the elements. By way of an example, a first element is distinct from a second element, and the first element may encompass more than one element and succeed (or precede) the second element in an ordering of elements.
It is to be understood that the singular forms “a,” “an,” and “the” include plural referents unless the context clearly dictates otherwise. Thus, for example, reference to “a fluid sample” includes reference to one or more of such samples.
Terms such as “approximately,” “substantially,” “about,” etc., mean that the recited characteristic, parameter, or value need not be achieved exactly, but that deviations or variations, including for example, tolerances, measurement error, measurement accuracy limitations and other factors known to those of skill in the art, may occur in amounts that do not preclude the effect the characteristic was intended to provide.
It is to be understood that one or more of the steps shown in the flowcharts may be omitted, repeated, and/or performed in a different order than the order shown. Accordingly, the scope of the invention should not be considered limited to the specific arrangement of steps shown in the flowcharts.
In the following description of the figures, any component described regarding a figure, in various embodiments disclosed herein, may be equivalent to one or more like-named components described with regard to any other figure. For brevity, descriptions of these components will not be repeated regarding each figure. Thus, each and every embodiment of the components of each figure is incorporated by reference and assumed to be optionally present within every other figure having one or more like-named components. Additionally, in accordance with various embodiments disclosed herein, any description of the components of a figure is to be interpreted as an optional embodiment which may be implemented in addition to, in conjunction with, or in place of the embodiments described with regard to a corresponding like-named component in any other figure.
Embodiments disclosed herein generally relate to an indium oxide (In2O3) catalyst composition containing an alkali dopant. One or more embodiments also relate to a method to produce an In2O3 catalyst composition containing an alkali dopant. Additionally, one or more embodiments relate to a process for reacting an In2O3 catalyst composition containing an alkali dopant in a RWGS reaction to form CO.
A few examples of catalysts for high-pressure RWGS have been previously reported, however, with significant formation of methane. In cases where methane formation is hindered, these catalysts still require relatively high temperatures (above 500° C.)
Therefore, a need exists for an improved In2O3 catalyst which increases the conversion rate of CO2 to CO while minimizing the selectivity to undesirable side products, for example methane (CH4) or methanol (CH3OH). As used herein, the term “selectivity” of a catalyst is the ability to produce a product, desirable or undesirable, and the term “conversion” refers to the amount of a reactant which has reacted. Doping of an In2O3 catalyst with an alkali metal according to one or more embodiments presented herein produces a catalyst composition which maximizes CO production in a RWGS reaction that is performed at high pressure (i.e., above about 30 bar) and low temperature (i.e., below about) 500°.
As noted above, one or more embodiments of the present disclosure relate to an indium oxide (In2O3) catalyst composition containing an alkali dopant. In one or more embodiments, indium hydroxide [In(OH)3], In2O3, or a mixture thereof, may be prepared as a starting point for producing an alkali-doped In2O3 catalyst composition. The In(OH)3 and In2O3 compounds, or a mixture thereof, may be obtained commercially or produced according to methods provided in later sections.
In general, the use of an In2O3 catalyst in an RWGS reaction has high selectivity to CH3OH production and relatively low CO production at low reaction temperatures and high reaction pressures. Therefore, when CO is the desired product, high reaction temperatures, and low reaction pressures are typically required.
In2O3 catalyst doped with an alkali metal according to embodiments herein provides improved selectivity for enhanced CO production at low or high pressures (i.e., from ambient pressure to 50 bar) and moderate temperatures (less than about 500° C.) compared to the In2O3 catalyst alone.
The term “dopant” refers to a substance added to a composition to modify or improve the properties of the composition. Specifically, a dopant according to embodiments herein refers to an alkali metal which is added to In(OH)3 or In2O3 catalyst to produce an alkali-doped In2O3 catalyst.
In one or more embodiments, an alkali-dopant may be any alkali metal cation selected from group one of the periodic table, including lithium (Li+), sodium (Na+), potassium (K+), rubidium (Rb+), cesium (Cs+), francium (Fr+), or combinations therein.
In one or more embodiments, an alkali-dopant may be added to an In2O3 catalyst to produce an alkali-doped In2O3 catalyst in an amount in the range of from about 0.5 wt. % to about 10 wt. % based on the total weight of the catalyst, such as a lower limit selected from any one of 0.5, 2, and 5 wt. %, to an upper limit selected from any one of 7, 9 and 10 wt. %, where any lower limit may be paired with any upper limit.
In one or more embodiments, the alkali-doped In2O3 catalyst may have a particle size in the range of from about 10 nm to about 200 nm, such as a lower limit selected from any one of 10, 25, and 50 nm, to an upper limit selected from any one of 75, 100 and 200 nm, where any lower limit may be paired with any upper limit. The particle size of the alkali-doped In2O3 catalyst may be isolated or formed from larger aggregates.
In one or more embodiments, the alkali-doped In2O3 catalyst may be amorphous, or have cubic, or hexagonal crystal unit cells, or mixtures thereof.
In one or more embodiments, the alkali-doped In2O3 catalyst may have a surface area in the range of from about 7 to about 55 m2/g, such as a lower limit selected from any one of 7, 10, 15 and 20 m2/g to an upper limit selected from any one of 25, 50, and 55 m2/g.
As noted above, one or more embodiments also relate to a method to produce an In2O3 catalyst composition containing an alkali dopant. In one or more embodiments, the method for producing an alkali-doped In2O3 catalyst includes preparing indium hydroxide, impregnating the indium hydroxide with a solution of an alkali metal salt, and then calcinating to form an In2O3 catalyst containing an alkali dopant.
The mixing of an indium salt solution with a base to form precipitated indium hydroxide may be done using any method known in the art, for example a simple stirring mechanism such as a stir bar, high shear mixer, or a shaker may be used.
The indium salt may be any soluble indium compound including, but not limited to, indium nitrate, indium acetate, indium chloride, indium oxalate, or indium sulfate under any hydration form. The indium precursor may be present as a mixture of one or more of the indium compounds.
The solution of an indium salt may have a concentration suitable to reach the maximum solubility of the salt in the reaction solvent. As will be appreciated by those skilled in the art, the solubility of the indium salt varies based on the salt and solvent(s) used. For instance, for reactions in water using indium nitrate, the concentration may be between 0.01 M and 4.00 M. However, this concentration range will change from salt-to-salt, so the range is used for illustrative purposes only. Thus, a suitable concentration to fully saturate the solvent may be used in each reaction.
The solution of an indium salt may be combined with a base to form precipitated indium hydroxide. Examples of the base include, but are not limited to, ammonium hydroxide, an alkali metal hydroxide, or a quaternary ammonium hydroxide, or mixtures thereof.
In one or more embodiments, the base is used to control the pH of the solution to promote the precipitation of indium hydroxide. The pH of solution may be in a range of from about 3 to about 12, such as a lower limit selected from any one of 3, 4, 6 and 7, to an upper limit selected from any one of 9, 10, and 12.
Upon combining the solution of an indium salt with the base, precipitated indium hydroxide is formed. Keeping with
The drying of indium hydroxide may be conducted at a temperature in a range of from about 20° C. to about 120° C., such as a lower limit selected from any one of 20, 25, and 50 to an upper limit selected from any one of 60, 75, 100 and 120° C., where any lower limit may be paired with any upper limit.
The drying of indium hydroxide may be conducted for a range of from about 1 h to about 15 h, such as a lower limit selected from any one of 1, 5, and 7 h to an upper limit selected from any one of 10, 12, and 15 h, where any lower limit may be paired with any upper limit.
In one embodiment, the method for producing an alkali-doped In2O3 catalyst includes contacting the indium hydroxide with a solution containing an alkali metal salt to form an alkali-impregnated-indium hydroxide as shown in step 102 of
In one or more embodiments, the alkali metal salt may be an alkali metal nitrate, an alkali metal chloride, an alkali metal sulfate, or an alkali metal carbonate. For example, the alkali metal nitrate may be lithium nitrate, sodium nitrate, potassium nitrate, rubidium nitrate, cesium nitrate, or combinations thereof. The alkali metal chloride may be lithium chloride, sodium chloride, potassium chloride, rubidium chloride, cesium chloride, or combinations thereof. The alkali metal nitrate may be lithium nitrate, sodium nitrate, potassium nitrate, rubidium nitrate, cesium nitrate, or combinations thereof. The alkali metal sulfate may be lithium sulfate, sodium sulfate, potassium sulfate, rubidium sulfate, cesium sulfate, or combinations thereof. The alkali metal carbonate may be lithium carbonate, sodium carbonate, potassium carbonate, rubidium carbonate, cesium carbonate, or combinations thereof.
The alkali metal salt solution may have a concentration in a range of from about 0.01 M to about 4 M, such as a lower limit selected from any one of 0.01, 0.1, 0.5, and 1 M, to an upper limit selected from any one of 2, 3, and 4 M where any lower limit may be paired with any upper limit. However, this concentration range will change from salt-to-salt, so the range is used for illustrative purposes only.
Contacting the indium hydroxide with an alkali metal salt solution may be conducted at a temperature in a range of from about 20° C. to about 120° C., such as a lower limit selected from any one of 20, 25, and 50 to an upper limit selected from any one of 60, 75, 100 and 120° C., where any lower limit may be paired with any upper limit.
Contacting the indium hydroxide with an alkali metal salt solution may be conducted for a duration in a range of from about 1 min to about 12 hours, such as a lower limit selected from any one of 1, 10, 30, and 60 min, to an upper limit selected from any one of 2, 5, 10, 12, and 15 h, where any lower limit may be paired with any upper limit.
Contacting the indium hydroxide with an alkali metal salt solution may be conducted by any method known in the art. For example, a simple wetness impregnation may be carried out. In this case, the alkali metal salt solution may be added to solid, powdered indium hydroxide until it fills the indium hydroxide's pores. Alternatively, the solid, powdered indium hydroxide may be added to the alkali metal salt solution and then mixed. The mixing may be done by any method known in the art, for example via a simple mixer such as a stir bar or using a high shear mixer. In this case, the alkali metal from the alkali metal solution diffuses into the indium hydroxide structure.
Upon contacting the indium hydroxide with a solution containing an alkali metal salt, an alkali-impregnated-indium hydroxide is formed. Keeping with
The drying of the alkali-impregnated-indium hydroxide may be conducted at a temperature in a range of from about 20° C. to about 120° C., such as a lower limit selected from any one of 20, 25, and 50 to an upper limit selected from any one of 60, 75, 100 and 120° C., where any lower limit may be paired with any upper limit.
The drying of alkali-impregnated-indium hydroxide may be conducted for a range of from about 1 h to about 15 h, such as a lower limit selected from any one of 1, 5, and 7 h to an upper limit selected from any one of 10, 12, and 15 h, where any lower limit may be paired with any upper limit.
The method for producing an alkali-doped In2O3 catalyst includes calcinating the alkali-impregnated-indium hydroxide to form In2O3 as shown in step 104 of
Calcinating the alkali-impregnated-indium hydroxide to form an alkali-doped In2O3 may be conducted at a temperature in a range of from about 250 to about 700° C., such as a lower limit selected from any one of 250, 300, and 400° C., to an upper limit selected from any one of 500, 600, and 700° C., where any lower limit may be paired with any upper limit.
Calcinating the alkali-impregnated-indium hydroxide to form an alkali-doped In2O3 may be conducted for a duration in a range of from about 1 h to about 15 h, such as a lower limit selected from any one of 1, 3, 5, and 6 hours, to an upper limit selected from any one of 10, 12, and 15 hours, where any lower limit may be paired with any upper limit.
Calcinating the alkali-impregnated-indium hydroxide to form an alkali-doped In2O3 catalyst may be done by any method known to the art, for example the indium hydroxide may be heated in a muffle or tube furnace, or the like, under air or another oxygen-containing atmosphere.
Upon calcinating the alkali-impregnated-indium hydroxide an alkali-doped In2O3 is formed.
In another embodiment, the indium hydroxide produced via precipitation in steps 100 and 101 of
In
Calcinating the indium hydroxide to form In2O3 may be conducted at a temperature in a range of from about 250 to about 700° C., such as a lower limit selected from any one of 250, 300, and 400° C., to an upper limit selected from any one of 500, 600, and 700° C., where any lower limit may be paired with any upper limit.
Calcinating the indium hydroxide to form In2O3 may be conducted for a duration in a range of from about 1 to about 15 h, such as a lower limit selected from any one of 1, 3, 5, and 6 hours, to an upper limit selected from any one of 10, 12, and 15 hours, where any lower limit may be paired with any upper limit.
Calcinating the indium hydroxide to form In2O3 may be done by any method known to the art, for example the indium hydroxide may be heated in a muffle or tube furnace, or the like, under air or another oxygen-containing atmosphere.
Once In2O3 has been formed via calcination of the indium hydroxide, in one or more embodiments, the method for producing an alkali doped In2O3 catalyst includes contacting the In2O3 with an alkali metal salt solution to form an alkali-doped In2O3 catalyst as shown in step 106 of
The alkali metal salt solution may be any alkali metal salt solution described previously. The concentration of the alkali metal salt solution may be the concentration of the alkali metal salt solution described previously.
Contacting the In2O3 with an alkali metal salt solution may be conducted at a temperature in a range of from about 20° C. to about 120° C., such as a lower limit selected from any one of 20, 25, and 50 to an upper limit selected from any one of 60, 75, 100 and 120° C., where any lower limit may be paired with any upper limit.
Contacting the In2O3 with an alkali metal salt solution may be conducted for a duration in a range of from about 1 min to about 12 hours, such as a lower limit selected from any one of 1, 10, 30, and 60 min, to an upper limit selected from any one of 2, 5, 10, 12, and 15 h, where any lower limit may be paired with any upper limit.
Contacting the In2O3 with an alkali metal salt solution may be conducted by any method known in the art. For example, a simple wetness impregnation may be carried out. In this case, the alkali metal salt solution may be added to solid, powdered indium hydroxide until it fills the indium hydroxide's pores. Alternatively, the solid, powdered indium hydroxide may be added to the alkali metal salt solution and then mixed. The mixing may be done by any method known in the art, for example via a simple mixer such as a stir bar or using a high shear mixer. In this case, the alkali metal from the alkali metal solution diffuses into the indium hydroxide structure.
Upon contacting the In2O3 with a solution containing an alkali metal salt, an alkali-doped In2O3 catalyst is formed.
The drying of alkali-doped In2O3 catalyst may be conducted at a temperature in a range of from about 20° C. to about 120° C., such as a lower limit selected from any one of 20, 25, and 50 to an upper limit selected from any one of 60, 75, 100 and 120° C., where any lower limit may be paired with any upper limit.
The drying of alkali-doped In2O3 catalyst may be conducted for a range of from about 1 h to about 12 h, such as a lower limit selected from any one of 1, 5, and 7 h to an upper limit selected from any one of 10, 12, and 15 h, where any lower limit may be paired with any upper limit.
In yet another embodiment, the method for producing an alkali-doped In2O3 catalyst includes mixing an indium salt solution with an alkali metal base to form a precipitated alkali-impregnated-indium hydroxide. The alkali-impregnated-indium hydroxide is separated by filtration or centrifugation, dried, and calcinated to produce an alkali-doped In2O3 catalyst.
In
The alkali metal base may be lithium hydroxide, sodium hydroxide, potassium hydroxide, rubidium hydroxide, cesium hydroxide, or combinations thereof. In one or more embodiments, the alkali metal base may be a mixture of one or more alkali metal bases and/or non-alkali metal bases. The non-alkali metal bases may include, but are not limited to, those described previously.
In one or more embodiments, the base is used to control the pH of the solution to promote the precipitation of indium hydroxide. The pH of solution may be in a range of from about 3 to about 12, such as a lower limit selected from any one of 3, 4, 6 and 7, to an upper limit selected from any one of 9, 10, and 12.
The mixing of an indium salt solution with an alkali metal base may be done using any method known in the art, for example a simple stirring mechanism such as a stir bar, high shear mixer, or a shaker may be used.
The indium salt may be any of the indium salts described previously.
Upon mixing the indium salt solution with the alkali metal base, a precipitated alkali-impregnated-indium hydroxide is formed.
In one or more embodiments the method to produce an alkali-doped In2O3 catalyst includes separating, by filtration or centrifugation, and drying the alkali-impregnated-indium hydroxide as shown in step 112 of
The drying of the alkali-impregnated-indium hydroxide may be conducted at a temperature in a range of from about 20° C. to about 120° C., such as a lower limit selected from any one of 20, 25, and 50 to an upper limit selected from any one of 60, 75, 100 and 120° C., where any lower limit may be paired with any upper limit.
The drying of alkali-impregnated-indium hydroxide may be conducted for a range of from about 1 h to about 12 h, such as a lower limit selected from any one of 1, 5, and 7 h to an upper limit selected from any one of 10, 12, and 15 h, where any lower limit may be paired with any upper limit.
The method for producing an alkali-doped In2O3 catalyst includes calcinating the alkali-impregnated-indium hydroxide to form In2O3 as shown in step 114 of
Calcinating the alkali-impregnated-indium hydroxide to form an alkali-doped In2O3 may be conducted at a temperature in a range of from about 250 to about 700° C., such as a lower limit selected from any one of 250, 300, and 400° C., to an upper limit selected from any one of 500, 600, and 700° C., where any lower limit may be paired with any upper limit.
Calcinating the alkali-impregnated-indium hydroxide to form an alkali-doped In2O3 may be conducted for a duration in a range of from about 1 to about 12 h, such as a lower limit selected from any one of 1, 3, 5, and 6 hours, to an upper limit selected from any one of 10, 12, and 15 hours, where any lower limit may be paired with any upper limit.
Calcinating the alkali-impregnated-indium hydroxide to form an alkali-doped In2O3 catalyst may be done by any method known to the art, for example the indium hydroxide may be heated in a muffle or tube furnace, or the like, under air or another oxygen-containing atmosphere.
Upon calcinating the alkali-impregnated-indium hydroxide an alkali-doped In2O3 is formed.
In general, reverse water gas shift (RWGS) reaction refers to the conversion of CO2 to CO, as shown in the chemical reaction of Equation 1.
CO2+H2CO+H2O Equation 1
The equilibrium of the RWGS reaction is highly temperature dependent. At high pressure, secondary reactions producing side products shown in Equations 2 and 3, are favorable. Equations 2 and 3 depict methanation reactions, in which carbon oxides and hydrogen are converted to methane and water. Therefore, when CO is the desired product, high reaction temperatures and low reaction pressures are typically required.
CO+3H2→CH4+H2O Equation 2
CO2+4H2→CH4+2H2O Equation 3
Performing the RWGS reaction with the alkali-doped In2O3 catalyst according to embodiments herein provides improved selectivity for enhanced CO production at high pressures (i.e., 50 bar) and moderate temperatures (<500° C.) compared to an In2O3 catalyst alone.
Keeping with
In
Keeping with
The CO stream 210 may be sent to a CO conversion process 212 for further processing. The CO conversion process of
The examples and comparative examples described in the following sections are provided to further illustrate the present invention but are not to be taken as limiting.
Example 1 was prepared by dissolving 6 g of indium nitrate in 100 ml of water. Under stirring, 30% aqueous solution of ammonium hydroxide to the metal solution until pH of 7. The dispersion was stirred for 10 min, and the indium hydroxide was separated by centrifugation. The solid was washed with water, dried for 15 h at 80° C. The resulting indium hydroxide was ground in a mortar.
Example 2 was prepared taking 1.17 g of Example 1 underwent impregnation with a solution containing 0.074 g of NaNO3 and 0.55 mL of water. The mixture was dried for 1.5 h at 100° C. and then calcinated for 3 h at 350° C. to form a Na-doped In2O3 catalyst containing 2 wt. % Na (Na/In2O3).
Example 3 was prepared by the same procedure as Example 2, except 0.074 g of NaNO3 was replaced by 0.052 g of KNO3 to form a K-doped In2O3 catalyst containing 2 wt. % K (K/In2O3).
Example 4 was prepared by the same procedure as Example 2, 0.074 g of NaNO3 was replaced by 0.035 g of RbNO3 to form a Rb-doped In2O3 catalyst containing 2 wt. % Rb (Rb/In2O3).
Example 5 was prepared by the same procedure as Example 2, except 0.074 g of NaNO3 was replaced by 0.029 g of CsNO3 to form a Cs-doped In2O3 catalyst containing 2 wt. % Cs (Cs/In2O3).
Comparative Example 1 was 99.9% commercial indium oxide catalyst acquired by Sigma-Aldrich (In2O3-Comm).
Comparative Example 2 was prepared impregnating 0.98 g of commercial indium oxide with a solution containing 0.074 g of NaNO3 and 0.77 mL of water. The mixture was dried for 1.5 h at 100° C. and then calcinated for 3 h at 350° C. to form a Na-doped In2O3 catalyst containing 2 wt. % Na (Na/In2O3-Comm).
Comparative Example 3 was prepared by the same method as Comparative Example 2, except 0.074 g of NaNO3 was replaced by 0.052 g of KNO3 to form a K-doped In2O3 catalyst containing 2 wt. % K (K/In2O3-Comm).
Comparative Example 4 was prepared by the same method as Comparative Example 2, except 0.074 g of NaNO3 was replaced by 0.035 g of KNO3 to form a Rb-doped In2O3 catalyst containing 2 wt. % Rb (Rb/In2O3-Comm).
Comparative Example 5 was prepared by the same method as Comparative Example 2, 0.074 g of NaNO3 was replaced by 0.029 g of KNO3 to form a Cs-doped In2O3 catalyst containing 2 wt. % Cs (Cs/In2O3-Comm).
Examples 1-5 and Comparative Examples 1-5 were used as a catalyst for a RWGS reaction to produce carbon monoxide (CO). The reaction bed was loaded with a catalyst selected from Examples 1-5 or Comparative Examples 1-5 and the reaction was conducted at 400° C. and 50 bar. A gas feed containing hydrogen/carbon dioxide (H2/CO2) at a 4:1 molar ratio was fed into a parallel reactor Flowrence® from Avantium reactor at a gas hourly space velocity (GHSV) of 15,000 mL/g/h.
Catalytic tests were conducted using the parallel reactor Flowrence® from Avantium. The system distributed one mixed feed gas flow over 16 channels, ensuring a relative standard deviation of 2%. The mixed feed gas consisted of approximately 20 vol % of CO2 and 80 vol % of H2. Additionally, 2 mL/min of He was added to the feed as an internal standard. The target flow rate per channel was set at 15000 mL/g/h. Quartz reactors measuring 30 cm in length with an internal diameter of 2 pm were used.
To ensure an isothermal zone for the placement of the catalytic bed, the tubes were initially filled with a 9.5 cm bed of coarse SiC (particle grit 40, 300 pi). Subsequently, 50 mg of catalyst particles within the range of 150 μm and 250 pm were loaded. As a control, a blank test was conducted with a reactor filled solely with SiC after every 45 catalytic runs.
Before introducing the reaction mixture, all samples were pretreated in-situ with a pure N2 atmosphere for approximately 1 h at 400° C. The tubes were then pressurized to approximately 50 bar using a membrane-based pressure controller that operated with N2 pressure. The analysis of the resulting products was performed using an Agilent 7890B chomatograph equipped with two loops. One loop was connected to the Column 5 Flaysep Q 6 Ft G3591-80013 and TCD, while the second loop was connected to the Gaspro 30M, 0.32 MM OD column followed by FID.
Results for the RWGS reaction of Examples 1-5 and Comparative Examples 1-5 at 400° C. 50 bar, and 15,000 mL/g/h H2/CO2 at a 4:1 molar ratio feed gas are shown in
In
The highest performing catalyst of the example reaction at 50 bar, Example 3 (K/In2O3), was subjected to further testing in which the RWGS reaction was conducted at various reaction conditions. For comparison, Example 1 was run at the same various reaction conditions. Examples 1 and 3 were used as a catalyst for a RWGS reaction to produce carbon monoxide (CO) in which the reaction bed was loaded Example 1 or Example 3 catalyst, and the reaction was conducted at various temperatures, pressures, and feed gas GHSV conditions, as listed in Tables 1-1 and 1-2. In all reactions, the gas feed contained hydrogen/carbon dioxide (H2/CO2) at a 4:1 molar. The same reactor type was used as described in previous examples.
Results for RWGS reactions at the various reaction conditions listed in Tables 1 and 2 are shown with Example 3 as the catalyst in
Although only a few example embodiments have been described in detail above, those skilled in the art will readily appreciate that many modifications are possible in the example embodiments without materially departing from this invention. In addition, many modifications will be appreciated by those skilled in the art to adapt a particular instrument, situation, or material to embodiments of the disclosure without departing from the essential scope thereof. Accordingly, all such modifications are intended to be included within the scope of this disclosure as defined in the following claims.
Furthermore, the compositions described herein may be free of any component, or composition not expressly recited or disclosed herein. Any method may lack any step not recited or disclosed herein. Likewise, the term “comprising” is considered synonymous with the term “including.” Whenever a method, composition, element, or group of elements is preceded with the transitional phase “comprising,” it is understood that we also contemplate the same composition or group of elements with transitional phases “consisting essentially of,” “consisting of,” “selected from the group of consisting of,” or “is” preceding the recitation of the composition, element, or elements and vice versa.
Unless otherwise indicated, all numbers expressing quantities of ingredients, properties such as molecular weight, reaction conditions, and so forth used in the present specification and associated claims are to be understood as being modified in all instances by the term “about.” Accordingly, unless indicated to the contrary, the numerical parameters set forth in the following specification and attached claims are approximations that may vary depending upon the desired properties sought to be obtained by one or more embodiments described herein. At the very least, and not as an attempt to limit the application of the doctrine of equivalents to the scope of the claim, each numerical parameter should at least be construed in light of the number of reported significant digits and by applying ordinary rounding techniques.
