Conversion of synthesis gas to liquid fuels

Abstract

This provides a catalyst system and corresponding method for a single-stage conversion of syngas into fuel boiling range products, which is effective for naphtha production (C5-C9) or distillate production (C6-C9). 10 -C 20 It exhibits enhanced selectivity. This enhanced selectivity for naphtha production or distillate production is related to the increased selectivity for higher boiling range components (C...). 21+ The reduced selectivity is provided together with the )

Description

[0001] Cross-references to related applications

[0002] This application relates to and claims the benefit of priority to U.S. Provisional Application No. 63 / 219,746, filed July 8, 2021, which is incorporated herein by reference in its entirety. Technical Field

[0003] Systems and methods are provided for converting syngas into fuel compounds within the boiling range in a single reaction stage, while reducing or minimizing the generation of higher boiling components. Background Technology

[0004] One way to convert natural gas resources into liquid fuels is to reform the natural gas to produce syngas, and then use the syngas to form liquid fuels. The Fischer-Tropsch reaction provides a known pathway for converting syngas into hydrocarbons and hydrocarbon compounds.

[0005] While the Fischer-Tropsch reaction is efficient for converting syngas into larger-chain compounds, one of the challenges of the Fischer-Tropsch pathway is that the chain lengths of the compounds formed during the reaction follow an Anderson-Schulz-Flory (ASF) distribution. Achieving significant yields of naphtha and / or diesel boiling range compounds, based on this chain length distribution, also yields significant yields of waxy compounds with boiling points of 370°C or higher. These heavier compounds could potentially be used to form lubricants, but expanding the lubricant processing train requires substantial additional capital investment. Therefore, systems and methods that allow the formation of fuel boiling range compounds from syngas while reducing or minimizing the selectivity for forming longer-chain compounds with boiling points above the fuel boiling range are desirable. This reduced selectivity for longer-chain compounds preferably allows for the formation of still relatively large quantities of fuel boiling range compounds.

[0006] U.S. Patent 7,973,087 describes the conversion of syngas into liquid fuels using a mixture of a syngas conversion catalyst and a bifunctional catalyst. The syngas conversion catalyst is described as containing cobalt on a support containing an acidic component, and optionally further containing a promoter metal. The bifunctional catalyst is described as containing a hydrogenation component and an acidic component. Examples include bifunctional catalysts corresponding to Pd / ZSM-5 (MFI framework structure) and Pt / SSZ-33 (CON framework structure), both of which are three-dimensional mesoporous zeotype framework structures.

[0007] U.S. Patent 4,794,099 describes a catalyst for Fischer-Tropsch synthesis. The catalyst comprises cobalt supported on an inorganic refractory carrier. The catalyst is further doped with silica.

[0008] A journal article by Kibby et al. describes a mixed conversion catalyst for the conversion of syngas to hydrocarbons. (Catalysis Today, Vol. 215 (2013), pp. 131-141.) The article describes the loading of cobalt and ruthenium on ZSM-5 (MFI framework structure) and ZSM-12 (MTW framework structure). MTW is a one-dimensional mesoporous zeolite framework structure. In the results presented here, the distillate compound (C...) of the mixed catalyst... 10 -C 20 The yield is lower than that of simply exposing the syngas feed to the corresponding FT synthesis catalyst.

[0009] A journal article by Martinez et al. describes hybrid conversion catalysts for the conversion of syngas into hydrocarbons. (Journal of Catalysis, Vol. 249 (2007), pp. 162-173.) The article describes several types of hybrid catalyst systems with Fischer-Tropsch synthesis activity and acidic function for syngas conversion, including catalysts incorporating USY zeolite (FAU framework structure). Based on the Brønsted acidity values ​​reported in the article, it is believed that the α value of all zeolite structures in the article is greater than 110. Summary of the Invention

[0010] In some aspects, a catalyst system is provided. The catalyst system comprises a hydrocarbon synthesis catalyst, wherein the hydrocarbon synthesis catalyst comprises 5.0 wt% or more cobalt on the oxide support relative to the weight of the oxide support. Additionally, the catalyst system comprises an acid catalyst having an α value of 2.0 to 100, comprising an amorphous oxide, a zeolite-type framework with a pore size of 6.5 Å or greater, or a combination thereof. The first catalyst and the second catalyst may correspond to a catalyst mixture in a weight ratio of 0.1 to 9.0.

[0011] In other aspects, a catalyst system is provided. The catalyst system comprises a hydrocarbon synthesis catalyst, wherein the hydrocarbon synthesis catalyst comprises 5.0 wt% or more cobalt on the oxide support relative to the weight of the oxide support. Additionally, the catalyst system comprises an acid catalyst having an α value of 80 or greater, comprising an MWW zeolite framework, a UFI zeolite framework, or a combination thereof. The first catalyst and the second catalyst may correspond to a catalyst mixture in a weight ratio of 0.1 to 9.0. Optionally, the acid catalyst may further comprise an amorphous oxide binder.

[0012] In some aspects, a method for converting a feedstock containing syngas is provided. The method comprises exposing the feedstock comprising syngas to a catalyst system as described herein under conversion conditions for converting 30 vol% or more of CO in the feedstock into hydrocarbons, said conversion conditions including temperatures from 190°C to 280°C. Attached Figure Description

[0013] Figure 1 The correlation between the α value of USY and Bronsted acidity is shown.

[0014] Figure 2 The correlation between the α value of ZSM-5 and Brønsted acidity is shown. Detailed Implementation

[0015] All numerical values ​​in the specific embodiments and claims herein are modified by the terms “about” or “approximately” and take into account experimental errors and variations that can be expected by one of ordinary skill in the art.

[0016] Overview

[0017] In various aspects, catalyst systems and corresponding methods are provided for single-stage conversion of syngas into fuel boiling-range products, exhibiting improved selectivity for naphtha production (C5-C9) or distillate production (C10-C20). This improved selectivity for naphtha or distillate production is related to the selectivity for higher boiling-range components (C5-C9). 21+ The reduced selectivity is provided together with the )

[0018] One characteristic of converting syngas into hydrocarbons using Fischer-Tropsch synthesis is that the selectivity for products with different carbon chain lengths follows an ASF distribution. Peaks in the distribution can be shifted by selecting different reaction conditions, but the overall shape remains consistent across conditions. Conventionally, one of the difficulties in forming fuels using Fischer-Tropsch synthesis is identifying the conditions that provide the desired fuel products. One option is to select conditions that minimize selectivity for methane and light gases. This increases the production of naphtha and distillate boiling-range compounds. However, since the products produced by conventional Fischer-Tropsch processes follow an ASF distribution, minimizing selectivity for methane and light gases also introduces a significant amount of C2O2. 21+ The formation of compounds. These waxes C 21+ The compounds are not easily incorporated into fuels, and often require further processing to convert waxy compounds into components with lower boiling ranges.

[0019] Some conventional synthetic methods have attempted to overcome the formation of waxy compounds by using catalyst systems that also contain hydrogenation and / or cracking catalysts. Adding other types of catalysts to the catalyst system used for syngas conversion can reduce Cg. 21+ The formation of compounds and / or in C 21+ After the compounds are formed, they are cracked to produce lower-boiling fractions. While this strategy is generally effective, further improvements are possible. For example, when distillate (e.g., diesel) fuel is the desired product, adding an additional catalyst to the catalyst system typically results in a decrease in diesel selectivity compared to using only a Fischer-Tropsch synthesis catalyst. Alternatively, when naphtha fuel is the desired product, while adding an additional catalyst to the syngas reforming catalyst system can increase the amount of naphtha, a higher selectivity for naphtha production would also be desirable.

[0020] In some aspects, catalyst systems for improved diesel selectivity have been provided. In such aspects, the catalyst system may comprise a Co-containing synthesis catalyst and an open-framework cracking catalyst with low to moderate acidity. The open-framework cracking catalyst may correspond to an amorphous catalyst or a zeolite-type catalyst with sufficiently large pores, such as the USY catalyst. The open-framework cracking catalyst may have an acidity corresponding to an α value of 100 or less, or 80 or less. This is unexpected, as conventionally, higher acidity in cracking catalysts is expected to provide improved results, partly due to the lower reaction temperatures at which the synthesis process takes place. However, it has been found that using acidic catalysts with only moderate or lower acidity can provide improved diesel yields. Without being bound by any particular theory, it is believed that the combination of a relatively open framework with low to moderate acidity allows larger waxy molecules to enter the active sites within the framework to facilitate conversion to distillate boiling range compounds, while reducing or minimizing excessive molecular cracking to naphtha boiling range compounds, which can occur under high-acidity catalysts. Optionally, a hydrogenated metal may be included as part of the open-framework cracking catalyst.

[0021] In other aspects, catalyst systems for enhancing naphtha selectivity have been provided. In such aspects, these catalyst systems can correspond to Co-containing synthesis and cracking catalysts, providing surface pockets for reaction with waxy molecules while possessing a porous structure that makes it relatively inaccessible to waxy compounds due to diffusion limitations. The MWW framework catalyst is an example of this type of structure. The MWW framework catalyst is a mesoporous catalyst. Without being bound by any particular theory, it is believed that the MWW framework structure only provides a limited opportunity for waxy molecules to enter the structural pores for reaction. However, the MWW framework catalyst also contains surface pockets that can serve as active sites for larger molecules. These surface sites are believed to increase the conversion of waxy compounds and distillate compounds while reducing or minimizing excessive cracking of naphtha into light gases (C). 4- It is believed that the UFI framework catalyst provides another instance of this type of structure.

[0022] definition

[0023] In this discussion, acidity is defined based on the α value of the catalyst. The α value is a measure of the acid activity of a zeolite catalyst (or more generally, a zeolite-type catalyst) compared to a standard silica-alumina catalyst. α tests are described in U.S. Patent No. 3,354,078; *Journal of Catalysis*, Vol. 4, p. 527 (1965); Vol. 6, p. 278 (1966); and Vol. 61, p. 395 (1980), each incorporated herein by reference. The experimental conditions used in the tests described herein included a constant temperature of 538 °C and variable flow rates, as detailed in *Journal of Catalysis*, Vol. 61, p. 395. Higher α values ​​correspond to more active cracking catalysts.

[0024] In this discussion, naphtha selectivity is defined based on the production of compounds containing 5 to 9 carbon atoms (C5-C9). In this discussion, diesel selectivity is defined based on compounds containing 10 to 20 carbon atoms (C6-C9). 10 -C 20 The compound is defined by the generation of the compound.

[0025] In this discussion, the space velocity of syngas is described relative to the weight of the synthesis catalyst (Fischer-Tropsch catalyst) in the catalyst system. An example of a unit used to describe space velocity is a certain number of liters of syngas per hour per gram of synthesis (Fischer-Tropsch) catalyst. This type of unit is abbreviated as L / g. FT / hr.

[0026] Diesel selective catalyst system

[0027] In some respects, diesel selective catalyst systems can be used to convert syngas into fuel boiling range products. These systems can comprise two types of catalyst particles. One type corresponds to a Co-containing catalyst with Fischer-Tropsch activity, where Co is supported on an oxide support. The second type corresponds to an open-framework catalyst with low to moderate acidity. This catalyst system has been found to unexpectedly provide higher diesel selectivity than Fischer-Tropsch catalysts alone, while also enabling the conversion of C... 21+ The selectivity of the compound is reduced or minimized.

[0028] Catalysts exhibiting Fischer-Tropsch conversion activity can correspond to Co-based catalysts. For example, the catalyst can correspond to Co nanoparticles supported on a low-acidity oxide support, such as silica, titanium dioxide, alumina, or combinations thereof. The catalyst may contain 5.0 wt% to 25 wt%, or 5.0 wt% to 20 wt%, or 5.0 wt% to 15 wt%, or 5.0 wt% to 10 wt% Co relative to the total weight of the catalyst. The α value of the support (before Co deposition) can be 20 or less, or 10 or less, or 5.0 or less, such as as low as 0.6 or possibly still lower. Alternatively or additionally, in some aspects, commercially available Co-based Fischer-Tropsch catalysts can be used. Co-based catalysts are preferred because they provide Fischer-Tropsch conversion activity at relatively low temperatures to mitigate common deactivation problems. Examples of Co-based Fischer-Tropsch catalysts are described in U.S. Patent 4,794,099.

[0029] In some aspects, the Co-based catalyst may further comprise a promoter metal. In such aspects, the activity of the catalyst can be enhanced by optionally adding a variety of metals as part of the catalyst support, said metal comprising sodium, potassium, copper, cerium, rhenium, manganese, platinum, palladium, iridium, rhodium, molybdenum, tungsten, ruthenium, or zirconium. Such catalysts are well known, and examples of such catalysts are described in U.S. Patent No. 4,568,663 and European Patent No. 0,266,898. In some aspects, the promoter metal may be ruthenium, rhenium, zirconium, or a combination thereof. In other aspects, the promoter metal may be Ru, Re, Mn, Zr, Ir, Au, Ag, Ce, Ba, or a combination thereof. In various aspects, the catalyst may comprise 0.05 wt% to 2.0 wt%, or 0.05 wt% to 1.5 wt%, or 0.2 wt% to 1.5 wt% of the promoter metal.

[0030] The catalyst system may also contain a catalyst with cracking activity. To provide diesel selectivity, the cracking catalyst can have low to moderate acidity while providing a relatively open framework. In various aspects, the α value of the cracking catalyst (before the addition of metals) can be 100 or less, or 80 or less, or 50 or less, or 25 or less, such as as low as 1.0 or possibly still lower.

[0031] In addition to having low to moderate acidity, cracking catalysts can also have a relatively open framework. This can be achieved, for example, by using amorphous cracking catalysts or by using zeolite-type cracking catalysts with sufficiently large pore structures. In the aspect of cracking catalysts having a zeolite-type framework, the cracking catalyst can contain pores with diameters of about 6.5 Å or greater, 7.0 Å or greater, or 7.5 Å or greater, or 8.0 Å or greater, such as up to 20 Å or possibly still higher. In this discussion, the pore diameter is defined as the diameter of the largest sphere that can diffuse along the pore. Examples of framework types with channels of 6.5 angstroms or larger in diameter include, but are not limited to, FAU (Zeolite Y, USY), DFO (DAF-1), EMT (EMC-2), ETR (ECR-34), GME (Gmelinite), IFT (ITQ-53), IFU (ITQ-54), MEI (ZSM-18), MOZ (ZSM-10), MSE (MCM-68), OFF (Offretite), and IWV (ITQ-27).

[0032] For cracking catalysts with amorphous supports, in some aspects, the amorphous supports can have a pore volume of 0.77 cm³. 3 / g or greater (e.g., as measured by Hg porosity determination), diameter 7.0 angstroms or greater, surface area >320 m² 2 / g holes, which provide a relatively open framework.

[0033] Optionally, the cracking catalyst may also contain a hydrogenated metal. Examples of hydrogenated metals include, but are not limited to, metals from Groups 8-10 of the IUPAC periodic table. In some aspects, the hydrogenated metal may be Pt, Pd, Rh, Ir, Co, Ni, Ru, or combinations thereof. For example, the hydrogenated metal may be Pt, Pd, or combinations thereof. The amount of hydrogenated metal relative to the weight of the cracking catalyst may be from 0.05 wt% to 5.0 wt% or from 0.05 wt% to 2.0 wt%.

[0034] Optionally, the cracking catalyst comprising a zeolite-type framework structure may further comprise an amorphous oxide binder. In such an optional aspect, the cracking catalyst may comprise 0.1 wt% to 50 wt%, or 0.1 wt% to 10 wt%, or 0.1 wt% to 5.0 wt% of the amorphous oxide binder.

[0035] A catalyst system with improved distillate selectivity can be formed by mixing a Co-containing synthesis catalyst with a distillate-selective cracking catalyst in a suitable ratio. In various aspects, the weight ratio of the Co-containing synthesis catalyst to the distillate-selective catalyst can range from 0.1 to 9.0 (i.e., 1:9 to 9:1). Any convenient type of catalyst mixture can be used. In some aspects, various types of catalyst particles can be mixed together to form a mixture of individual particles. In some aspects, various types of catalyst particles can be ground into powder, mixed together, and then pressed to form particles containing a mixture of various types of catalysts. In still other aspects, any convenient method for forming a physical mixture of two (or more) types of catalyst particles can be used.

[0036] Naphtha selective catalyst system

[0037] In some respects, naphtha-selective catalyst systems can be used to convert syngas into fuel boiling range products. These systems can comprise two types of catalyst particles. One type corresponds to a Co-containing catalyst with Fischer-Tropsch conversion activity, where Co is supported on an oxide support. The second type corresponds to a catalyst comprising an MWW zeolite framework. This catalyst system has been found to provide unexpectedly high naphtha selectivity.

[0038] Catalysts exhibiting Fischer-Tropsch activity can correspond to Co-based catalysts. For example, the catalyst can correspond to Co nanoparticles supported on a low-acidity oxide support, such as silica, titanium dioxide, alumina, or combinations thereof. The catalyst can contain 5.0 wt% to 25 wt%, or 5.0 wt% to 20 wt%, or 5.0 wt% to 15 wt%, or 5.0 wt% to 10 wt% Co relative to the total weight of the catalyst. The α value of the support (before Co deposition) can be 20 or less, or 10 or less, or 5.0 or less, such as as low as 0.1 or possibly still lower. Alternatively or alternatively, in some aspects, commercially available Co-based Fischer-Tropsch catalysts can be used. Co-based catalysts are preferred because they provide Fischer-Tropsch conversion activity at relatively low temperatures to mitigate common deactivation problems.

[0039] In some aspects, the Co-based catalyst may further comprise a promoter metal. In such aspects, the activity of the catalyst can be enhanced by optionally adding a variety of metals as part of the catalyst support, said metal comprising sodium, potassium, copper, cerium, rhenium, manganese, platinum, palladium, iridium, rhodium, molybdenum, tungsten, ruthenium, or zirconium. Such catalysts are well known, and examples of such catalysts are described in U.S. Patent No. 4,568,663 and European Patent No. 0,266,898. In some aspects, the promoter metal may be ruthenium, rhenium, zirconium, or a combination thereof. In other aspects, the promoter metal may be Ru, Re, Mn, Zr, Ir, Au, Ag, Ce, Ba, or a combination thereof. In various aspects, the catalyst may comprise 0.05 wt% to 2.0 wt%, or 0.05 wt% to 1.5 wt%, or 0.2 wt% to 1.5 wt% of the promoter metal.

[0040] The catalyst system may also contain a catalyst with cracking activity. To provide enhanced naphtha selectivity, the cracking catalyst may have surface pits that allow larger compounds to enter the active sites within the catalyst without requiring them to enter the interior of the catalyst's pore structure. Without being bound by any particular theory, it is believed that using cracking catalysts with surface pits allows larger compounds to crack without the cracking products becoming trapped in the pores and "over-cracking" to form lighter gases. The MWW framework structure is one example of a zeolite type providing surface pits for increased naphtha selectivity during syngas conversion. Examples of structures with the MWW framework include EMM-10, MCM-22, MCM-49, and MCM-56. The UFI framework structure is another example of a zeolite type providing surface pits suitable for increased naphtha selectivity. Furthermore, in various aspects, the α value of the cracking catalyst for naphtha selectivity can be 85 or greater, or 105 or greater, or 125 or greater, such as up to 400 or possibly still higher.

[0041] Optionally, the cracking catalyst may also contain a hydrogenated metal. Examples of hydrogenated metals include, but are not limited to, metals from Groups 8-10 of the IUPAC periodic table. In some aspects, the hydrogenated metal may be Pt, Pd, Rh, Ir, Co, Ni, Ru, or combinations thereof. For example, the hydrogenated metal may be Pt, Pd, or combinations thereof. The amount of hydrogenated metal relative to the weight of the cracking catalyst may be from 0.05 wt% to 5.0 wt% or from 0.05 wt% to 2.0 wt%.

[0042] Optionally, the cracking catalyst may comprise an amorphous oxide binder. In such an option, the cracking catalyst may comprise 0.1 wt% to 50 wt%, or 0.1 wt% to 10 wt%, or 0.1 wt% to 5.0 wt% of an amorphous oxide binder. SiO2 is an example of a suitable binder.

[0043] A catalyst system with improved naphtha selectivity can be formed by mixing a Co-containing synthesis catalyst with a naphtha selective cracking catalyst in a suitable ratio. In various aspects, the weight ratio of the Co-containing synthesis catalyst to the naphtha selective catalyst can range from 0.1 to 9.0 (i.e., 1:9 to 9:1). Any convenient type of catalyst mixture can be used. In some aspects, various types of catalyst particles can be mixed together to form a mixture of individual particles. In some aspects, various types of catalyst particles can be ground into powder, mixed together, and then pressed to form particles containing a mixture of various types of catalysts. In still other aspects, any convenient method for forming a physical mixture of two (or more) types of catalyst particles can be used.

[0044] Synthesis of hydrocarbon compounds—catalytic conversion of syngas

[0045] One process for converting syngas (sometimes called syngas) into fuel-boiling-range products is the Fischer-Tropsch process, in which syngas can be reacted over a catalyst at high temperatures and pressures, primarily producing long-chain hydrocarbons (or hydrocarbon-containing compounds) and potentially small amounts of oxygen-containing compounds. The most commonly used catalysts typically include iron-based catalysts (for so-called high-temperature Fischer-Tropsch synthesis) and cobalt-based catalysts (for so-called low-temperature Fischer-Tropsch synthesis). Iron-based catalysts, and other related catalysts, can also be called shift catalysts because the water-gas shift reaction can be readily equilibriumed over these catalysts. Co-containing catalysts and other related catalysts can be called non-shift catalysts because they appear to substantially not carry out and / or catalyze the water-gas shift equilibrium reaction under standard operating conditions below approximately 250°C. While other catalyst systems and process conditions can be used, cobalt- or iron-based catalysts are commonly used in commercial operations. In all respects, Co-containing catalysts may be preferred in the catalyst systems described herein.

[0046] The syngas feed used in a typical Fischer-Tropsch process can include a mixture of H2 and CO, wherein the H2:CO molar ratio is 1.7 or greater, or 2.1 or greater, such as 1.7 to 2.5, or 2.1 to 2.5, or 1.7 to 2.1. The Fischer-Tropsch process can be implemented in a variety of systems, such as fixed-bed, slurry-bed, and multi-channel designs. In various aspects, the Fischer-Tropsch process can be used in a variety of reactors, such as small reactors (e.g., 1+ barrels / day) or very large reactors (e.g., 10,000–50,000 barrels / day or more). The product, typically a hydrocarbon wax, can be used as is and / or can be converted into other (e.g., liquid) components through a variety of well-known chemical conversion processes.

[0047] Typically, the Fischer-Tropsch process can be operated in a temperature range of 150°C to 350°C (302℉-662℉) and a pressure range of 100 kPaa to 10 MPaa. In various aspects of the Fischer-Tropsch process using catalyst systems comprising both synthesis and cracking catalysts, the temperature range can be 190°C to 280°C, 190°C to 260°C, or 210°C to 260°C. In some aspects using amorphous catalysts as cracking catalysts for distillate-selective catalyst systems, the temperature range can be 210°C to 280°C, or 210°C to 260°C. The space velocity of the syngas relative to the weight of the synthesis catalyst (i.e., Co-containing Fischer-Tropsch catalyst) in the catalyst system can be 0.25-10.0 L / g of syngas per gram of catalyst, or 0.25-10.0 L / g. FT / hr. One method for selecting reaction conditions is to select conditions that efficiently convert 30 vol% or more, or 50 vol% or more, or 60 vol% or more, such as up to substantially complete conversion of the syngas (i.e., up to 100 vol%) in the conversion process feed, relative to the volume of syngas in the conversion process feed on a single-pass basis. The volume of syngas corresponds to the total volume of H2 and CO in the conversion process feed. In some aspects, fractions containing unconverted syngas can be separated from the conversion products and recycled back to the conversion process.

[0048] Modifying the reaction conditions in the Fischer-Tropsch process can provide control over the yield and / or composition of the reaction products, including at least some control over the chain length of the reaction products. Typical reaction products may include alkanes and alkenes (primary reaction products), as well as oxygen-containing compounds, other hydrocarbon-containing compounds similar to hydrocarbons but which may contain one or more heteroatoms other than carbon and hydrogen, and various additional reaction byproducts and / or unreacted feed components, one or more of these. Primary products from Fischer-Tropsch synthesis can be used directly and / or further processed as needed. For example, a Fischer-Tropsch synthesis process for forming distillate boiling range molecules can produce one or more product streams, which can then be dewaxed and / or hydrocracking to produce final products, for example, having desired chain lengths, viscosities, and cold flow properties.

[0049] In the use of distillate-selective catalyst systems, under similar conditions, the distillate compound (C) used to form said catalyst system... 10 -C 20 The selectivity of the catalyst can be greater than that of the distillate compounds synthesized alone. This is unexpected, because conventionally, the addition of cracking compounds inhibits the selectivity of the distillate (C... 10 -C 20 ) and wax (C 21+Selectivity of compounds. This enhanced selectivity for forming distillate compounds can be achieved under conversion conditions that result in 30 vol% or more of syngas conversion, or 40 vol% or more, or 50 vol% or more, or 60 vol% or more, such as up to substantially complete conversion (on a single-pass basis, relative to the volume of syngas in the conversion process feed).

[0050] In the use of naphtha-selective catalyst systems, the selectivity of naphtha compounds (C5-C9) used to form said catalyst system is unexpectedly high compared to other types of catalyst systems containing cracking catalysts. This enhanced selectivity for forming naphtha compounds can be achieved under conversion conditions that result in 30 vol% or more of syngas conversion, or 40 vol% or more, or 50 vol% or more, or 60 vol% or more, such as up to substantially complete conversion (on a single-pass basis, relative to the volume of syngas in the conversion process feed).

[0051] Example 1 - Comparison of α value and Brønsted acidity

[0052] In this discussion, the acidity of various catalysts is described using α-value tests. Other types of acidity characterization are also available. For example, another method for characterizing acidity is based on the Brønsted acidity of the catalyst. This can be determined, for example, by determining the amount of Brønsted acid sites based on the adsorption of pyridine at a specified temperature (e.g., 150 °C). The adsorption of pyridine at the acid sites can be determined using infrared (IR) spectroscopy.

[0053] It is worth noting that the number of Brønsted acid sites showing pyridine adsorption depends on temperature. As temperature increases, pyridine will desorb more and more from the weakly acidic sites, resulting in a decrease in the total amount adsorbed. Therefore, Brønsted acidity measurements at lower temperatures can be used as a lower limit for Brønsted acidity measurements at higher temperatures, because increasing the temperature will reduce the amount of pyridine adsorbed.

[0054] For a given type of acidic catalyst, the α value of the catalyst can be correlated with the Brønsted acidity. This correlation is typically linear. The slope of the linear correlation can vary depending on the properties of the catalyst. Figure 1 and Figure 2 Representative α values ​​for two different types of acid catalysts and their correlation with Brønsted acidity are provided. Figure 1 The correlation between the α value and Brønsted acidity of ultrastable γ zeolite (USY) is shown. Figure 2 The correlation between the α value of ZSM-5 and Brønsted acidity is shown. Figure 1 and Figure 2The correlation is shown in the Brønsted acidity measured at a pyridine adsorption temperature of 150 °C.

[0055] exist Figure 1 The diagram shows the correlation between the α value of USY and Brønsted acidity in mmol / g (as determined by IR spectroscopy). Figure 1 As shown, for every 10-unit increase in the α value, the corresponding Brønsted acidity increases by approximately 0.02 mmol / g or approximately 20 μmol / g. Therefore, an α value of 100 for the USY catalyst corresponds to a Brønsted acidity of approximately 0.2 mmol / g or 200 μmol / g measured at 150 °C. As mentioned above, since pyridine desorption increases with increasing temperature, a Brønsted acidity of 0.2 mmol / g at 250 °C would correspond to an even higher α value.

[0056] Figure 2 A similar correlation plot for ZSM-5 is shown. (e.g.) Figure 2 As shown, with Figure 1 As shown in the diagram, compared to USY, the α value of ZSM-5 increases more rapidly. For example, as... Figure 2 As shown, for ZSM-5, a Brønsted acidity of approximately 0.2 mmol / g measured at 150 °C corresponds to an α value of over 2000.

[0057] Similar correlation plots can also be prepared for any convenient type of zeolite framework. It is noteworthy that for mordenite (MOR), a Brønsted acidity of 0.4 mmol / g at 150 °C corresponds to an α value greater than 1000. For zeolite β, a Brønsted acidity of 0.18 mmol / g at 150 °C corresponds to an α value of approximately 700.

[0058] Example 2 - Naphtha Selectivity

[0059] To investigate naphtha selectivity, a series of catalyst systems were developed and placed in a laboratory-scale reactor. One part of the system was a Co-containing catalyst with Fischer-Tropsch conversion activity. The Co-containing catalyst contained 11 wt% Co on a titanium dioxide support, relative to its weight. Another part of the catalyst system was a cracking catalyst. The weight of the Co-containing catalyst was approximately equal to that of the cracking catalyst. The catalysts were ground into powder, mixed together, pressed, and sized to 50-60 mesh (250-300 μm) before being loaded into the reactor. Silicon carbide was also added as an inert diluent to maintain isothermal conditions inside the reactor. Before use for syngas conversion, the catalyst system was activated in hydrogen at 375°C or 400°C for at least 3 hours.

[0060] The cracking catalysts used in the catalyst system include the following: ZSM-5 (MFI framework); EMM-10 (MWW framework); zeolite β (BEA framework); ZSM-48 (MRE framework); and ZSM-12 (MTW framework). The maximum pore size of all these cracking catalysts is less than 7.0 Å. Additionally, 0.6 wt% Pt is supported on each of these cracking catalysts.

[0061] The catalyst system was used to convert syngas at a pressure of 20 bar-a (~2.0 MPa-a) and a temperature of 200 to 250 °C. For naphtha selectivity studies, all runs were performed at approximately 2.0 L / g. FT The reaction was carried out at a syngas hourly space velocity (SHSV) of 2.0 / hr. The molar ratio of H2 to CO in the syngas was 2.0. The product composition leaving the reactor was characterized by gas chromatography.

[0062] Table 1 shows the results of the naphtha selectivity study. In Table 1, the type of catalyst system is shown along with the temperature of the syngas. For comparison, the operation using only the Co-containing Fischer-Tropsch catalyst is also shown.

[0063] Table 1 - Naphtha Selectivity

[0064]

[0065]

[0066] As shown in Table 1, the catalyst system containing EMM-10 as a cracking catalyst exhibits unexpectedly higher naphtha selectivity than any other catalyst system, while also providing significantly lower wax selectivity relative to various catalyst systems. This unexpected benefit in naphtha selectivity was provided at CO conversion levels of 42 vol%, 59 vol%, and 73 vol%. This indicates that EMM-10 provides this unexpected naphtha selectivity at any commercially desirable CO (or syngas) conversion level. Notably, the α value of the EMM-10 catalyst is 140, significantly lower than that of the ZSM-5 catalyst, yet the catalyst system containing EMM-10 provides significantly higher naphtha selectivity. Therefore, it is believed that the improved naphtha selectivity of EMM-10 is attributed to the catalyst's framework structure, which includes a 7.0x... The 12-membered ring cavity is not present in the other cracking catalysts shown in Table 1.

[0067] Example 3 - Diesel Selectivity

[0068] It is worth noting that, in Table 1, the highest distillate selectivity (C) was observed.10 -C 20 The concentration was 20 wt%, achieved in one of the comparative runs using a Co-containing Fischer-Tropsch synthesis catalyst without the accompanying cracking catalyst. The lower distillate selectivity of the catalyst systems shown in Table 1 is believed to be due to the combination of higher acidity (i.e., higher α value) and smaller pore size. This view is based in part on the finding that using a cracking catalyst with medium to low acidity and a relatively open framework yields catalyst systems that can provide higher distillate selectivity compared to using only a synthesis catalyst.

[0069] Table 2 shows the results of studies on other catalyst systems. The results in Table 2 were generated in a similar manner to those shown in Table 1. One difference is the final catalyst system shown in Table 2. For the catalyst system containing unsupported hydrogenation metal USY, approximately 3.0 L / g was used. FT The synthesis gas space velocity is 1.0 L / hr, instead of the 2.0 L / g used in other operations. FT The / hr value. For ease of comparison, the operation of the synthesis (Fischer-Tropsch) catalyst, which is only included in Table 1, is also included in Table 2.

[0070] Table 2 - Distillate Selectivity

[0071]

[0072] Three types of catalyst systems were used to produce the results shown in Table 2. The first catalyst system contained a USY catalyst (containing channels with a size greater than 7.0 Å) and also contained 0.6 wt% Pt as the hydrogenation metal. The second catalyst system contained a higher acidity USY catalyst without a supported hydrogenation metal. The third catalyst system contained an amorphous silica-alumina catalyst with 0.5 wt% Pd as the supported hydrogenation metal.

[0073] As shown in Table 2, catalyst systems containing either USY or amorphous cracking catalysts exhibited unexpectedly higher distillate selectivity than when the synthesis catalyst was used alone. Therefore, the open framework and lower acidity of the catalysts used in the systems shown in Table 2 reduced wax selectivity while increasing distillate selectivity. Notably, the catalyst system containing the unsupported hydrogenation metal USY catalyst provided the highest distillate selectivity. However, the amorphous catalysts exhibited a greater reduction in wax selectivity compared to the USY catalyst.

[0074] Other embodiments

[0075] Example 1. A catalyst system comprising: a hydrocarbon synthesis catalyst, the hydrocarbon synthesis catalyst comprising 5.0 wt% or more cobalt on the oxide support relative to the weight of the oxide support; and an acid catalyst having an α value of 2.0 to 100, the acid catalyst comprising an amorphous oxide, a zeolite-type framework with a pore size of 6.5 angstroms or greater, or a combination thereof, the first catalyst and the second catalyst constituting a catalyst mixture in a weight ratio of the first catalyst to the second catalyst of 0.1 to 9.0.

[0076] Example 2. The catalyst system according to Example 1, wherein the α value of the acid catalyst is 2.0 to 80.

[0077] Example 3. The catalyst system according to any one of the preceding examples, wherein the acid catalyst comprises a FAU zeolite framework, or wherein the amorphous oxide comprises silica and alumina.

[0078] Example 4. A catalyst system comprising: a synthetic catalyst, wherein the synthetic catalyst comprises 5.0 wt% or more cobalt on the oxide support relative to the weight of the oxide support; and an acid catalyst having an α value of 80 or greater, the acid catalyst comprising an MWW zeolite framework, a UFI zeolite framework or a combination thereof, wherein the first catalyst and the second catalyst constitute a catalyst mixture in which the weight ratio of the first catalyst to the second catalyst is 0.1 to 9.0.

[0079] Example 5. The catalyst system according to Example 4, wherein the acid catalyst comprises an α value of 100 or greater, or wherein the acid catalyst further comprises an amorphous oxide binder, or wherein the acid catalyst comprises EMM-10, or a combination thereof.

[0080] Example 6. The catalyst system according to any one of the foregoing examples, wherein the acid catalyst does not contain a supported hydrogenation metal.

[0081] Example 7. A catalyst system according to any one of the preceding examples, wherein, relative to the weight of the acid catalyst, the acid catalyst further comprises 0.1 wt% to 5.0 wt% of a hydrogenation metal supported on the acid catalyst; or wherein, relative to the weight of the hydrocarbon synthesis catalyst, the hydrocarbon synthesis catalyst further comprises 0.05 wt% to 2.0 wt% of a promoter metal; or a combination thereof.

[0082] Example 8. According to the catalyst system of Example 7, i) the hydrogenation metal includes Pt, Pd or a combination thereof; ii) the promoter metal includes Ru, Re, Mn, Zr, Ir, Au, Ag, Ce, Ba or a combination thereof; or iii) a combination of i) and ii).

[0083] Example 9. A catalyst system according to any one of the foregoing examples, wherein the catalyst mixture comprises catalyst particles, the catalyst particles comprising a mixture of the hydrocarbon synthesis catalyst and the acid catalyst.

[0084] Example 10. A catalyst system according to any one of the preceding examples, wherein the α value of the oxide support of the synthesized catalyst is less than 2.0.

[0085] Example 11. A method for converting a feedstock containing syngas, the method comprising: exposing the feedstock containing syngas to a catalyst system under conversion conditions for converting 30 vol% or more of CO in the feedstock into hydrocarbons, the conversion conditions including a temperature of 190°C to 280°C, the catalyst system comprising the catalyst system according to any one of Examples 1 to 10.

[0086] Example 12. The method according to Example 11, wherein the conversion conditions include a temperature of 210°C to 260°C.

[0087] Example 13. The method according to Example 11 or 12, wherein the acid catalyst does not contain a supported hydrogenation metal.

[0088] Example 14. The method according to any one of Examples 11 to 13, wherein, relative to the weight of the acid catalyst, the acid catalyst further comprises 0.1 wt% to 5.0 wt% of a hydrogenation metal supported on the acid catalyst; or wherein the hydrocarbon synthesis catalyst further comprises 0.05 wt% to 2.0 wt% of a promoter metal; or a combination thereof.

[0089] Example 15. A synthetic product comprising hydrocarbons formed according to any one of Examples 11 to 14.

[0090] Another embodiment A. According to the catalyst system of Example 14, i) wherein the hydrogenation metal includes Pt, Pd or a combination thereof; ii) wherein the promoter metal includes Ru, Re, Zr or a combination thereof; or iii) a combination of i) and ii).

[0091] When lower and upper limits are listed herein, a range from any lower limit to any upper limit is considered. While illustrative embodiments of this disclosure have been specifically described, it should be understood that various other modifications will be apparent to those skilled in the art and readily available without departing from the spirit and scope of this disclosure. Therefore, the scope of the appended claims is not intended to be limited to the examples and descriptions set forth herein, but rather the claims are to be construed as covering all features of patentable novelty present in this disclosure, including all features that a person skilled in the art to which this disclosure pertains would consider its equivalents.

[0092] This disclosure has been described above with reference to numerous embodiments and specific examples. Many variations will arise in the mind of those skilled in the art from the detailed description above. All such obvious variations are within the full scope of the appended claims.

Claims

1. A catalyst system comprising: A hydrocarbon synthesis catalyst, wherein, relative to the weight of the oxide support, the hydrocarbon synthesis catalyst comprises 5.0 wt% or more cobalt on the oxide support; as well as An acid catalyst having an α value of 2.0 to 100, comprising amorphous oxides, zeolite-type frameworks with a pore size of 6.5 angstroms or larger, or combinations thereof. The hydrocarbon synthesis catalyst and the acid catalyst constitute a catalyst mixture in which the weight ratio of the hydrocarbon synthesis catalyst to the acid catalyst is 0.1 to 9.

0. The acid catalyst further comprises, relative to the weight of the acid catalyst, 0.1 wt% to 5.0 wt% of a hydrogenation metal supported on the acid catalyst; or the hydrocarbon synthesis catalyst further comprises, relative to the weight of the hydrocarbon synthesis catalyst, 0.05 wt% to 2.0 wt% of a promoter metal; or a combination thereof.

2. The catalyst system according to claim 1, wherein the α value of the acid catalyst is from 2.0 to 80.

3. The catalyst system according to claim 1, wherein the acid catalyst comprises a FAU zeolite framework, or wherein the amorphous oxide comprises silica and alumina.

4. The catalyst system according to claim 2, wherein the acid catalyst comprises a FAU zeolite framework, or wherein the amorphous oxide comprises silica and alumina.

5. The catalyst system according to claim 1, i) wherein the hydrogenation metal comprises Pt, Pd or a combination thereof; ii) wherein the promoter metal comprises Ru, Re, Mn, Zr, Ir, Au, Ag, Ce, Ba or a combination thereof; or iii) a combination of i) and ii).

6. The catalyst system according to any one of claims 1 to 5, wherein the catalyst mixture comprises catalyst particles, the catalyst particles comprising a mixture of the hydrocarbon synthesis catalyst and the acid catalyst.

7. The catalyst system according to any one of claims 1 to 5, wherein the α value of the oxide support of the synthesized catalyst is less than 2.

0.

8. The catalyst system according to claim 6, wherein the α value of the oxide support of the synthesized catalyst is less than 2.

0.

9. A method for converting a feedstock containing syngas, the method comprising: A feedstock comprising syngas is exposed to a catalyst system under conversion conditions for converting 30 vol% or more of CO in the feedstock into hydrocarbons, the conversion conditions including a temperature of 190°C to 280°C, the catalyst system comprising any one of claims 1 to 8.

10. The method of claim 9, wherein the conversion conditions include a temperature of 210°C to 260°C.

11. The method according to claim 9 or 10, wherein the acid catalyst does not contain a supported hydrogenation metal.

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