Patent Description:
The present disclosure is directed to hydrocarbon processing, in particular, to composite catalysts and methods of making composite catalysts for conducting olefin metathesis and cracking.

In recent years, there has been a dramatic increase in the demand for propene to feed the growing markets for polypropylene, propylene oxide, and acrylic acid. Currently, most of the propene produced worldwide (<NUM> million tons/year) is a by-product from steam cracking units (<NUM>%), which primarily produce ethylene, or a by-product from Fluid Catalytic Cracking (FCC) units (<NUM>%), which primarily produce gasoline. These processes cannot respond adequately to a rapid increase in propene demand.

Production of propene from a butene-containing stream, such as a Raffinate stream or other butene-containing stream, can be accomplished through metathesis of the butene to propene and other compounds in combination with cracking, isomerization, or both. Some propene processes include metathesis, isomerization, and cracking in order to increase the overall yield and propene selectivity of the reaction system. Each of these types of reactions can require a different type of catalyst, such as a cracking catalyst for the cracking reaction, a metathesis catalyst for the metathesis reaction, and an isomerization catalyst for the isomerization reaction. In conventional reaction system for converting butene to propene, the separate catalysts may be isolated in separate catalyst zones, such as by charging each of the separate catalysts to a separate reactor or by charging the catalyst to a single reactor and separating each catalyst with inert spacers, such as quartz wool or silicon carbide. Segregating the catalysts into separate reactor vessels substantially increases the initial capital cost of the reaction system. Additionally, separating the catalysts with inert spacers creates dead volumes in the reactor, which may reduce the efficiency of the reactor.

To reduce costs and eliminate dead zones, a physical catalyst mixture of two or more separate solid particulate catalyst materials may be used. However, these physical catalyst mixtures of different solid catalyst materials may gradually segregate in the reactor over time due to settling that occurs with continuing use and handling. This segregation, or settling, effect can be increasingly drastic when, for example, the physical properties of the separate solid particulate catalyst materials are significantly different, relative to the other catalyst materials in the physical catalyst mixture. Thus, the effectiveness of the physical catalyst mixtures of solid catalyst particles may decrease over time as the separate catalysts segregate through settling.

<CIT> and <CIT> disclose processes for preparing metathesis catalysts and their use in conversion of butene to propene.

Accordingly, there is an ongoing need for multi-functional composite catalysts and methods of synthesizing the composite catalysts. The present disclosure is directed to multi-functional composite catalysts and methods of producing the composite catalysts. The composite catalysts of the present disclosure may include a plurality of composite catalyst particles and each of the composite catalyst particles may include a plurality of different catalytically active constituents. Each of the plurality of catalytically active constituents in the composite catalyst may provide a different catalytic functionality to the composite catalyst particles. Thus, the multi-functional composite catalyst may combine multiple catalytic functionalities into a single particle. In particular, the composite catalysts of the present disclosure may include zeolite particles at least partially or fully embedded in a catalyst support material and a catalytically active compound deposited on the surfaces of the catalyst support material, the zeolite particles, or both. The composite catalyst may have a uniform distribution of the catalytically active compound across the outer surfaces and pore surfaces of the catalyst support material, the zeolite particles, or both. Thus, the composite catalyst may have substantially uniform physical properties and may not experience the drawbacks associated with settling of physical catalyst mixtures. The multi-functional composite catalyst may enable a single particulate catalyst to be charged to a reactor to conduct a plurality of different chemical reactions, such as combinations of isomerization, metathesis, and cracking, for producing propene from <NUM>-butene, for example.

The invention relates to a method of preparing a composite catalyst according to claim <NUM> and a method for producing propene according to claim <NUM>.

Additional features and advantages of the described embodiments will be set forth in the following detailed description and, in part, will be readily apparent to those skilled in the art from that detailed description or recognized by practicing the described embodiments, including the detailed description, the claims, as well as the appended drawings.

For the purpose of describing the simplified schematic illustrations and descriptions of <FIG> and <FIG> the numerous valves, temperature sensors, electronic controllers, and similar processing components that may be employed and well known to those of ordinary skill in the art of certain chemical processing operations may not be included. Further, accompanying components that are often included in typical chemical processing operations, carrier gas supply systems, pumps, vessel agitators, compressors, furnaces, or other subsystems may not be depicted. However, operational components, such as those described in the present disclosure, may be added to the embodiments described in this disclosure.

Arrows in the Figures refer to process streams. However, the arrows may equivalently refer to transfer lines which may serve to transfer process streams between two or more system components. Additionally, arrows that connect to system components may define inlets or outlets in each given system component. The arrow direction corresponds generally with the major direction of movement of the materials of the stream contained within the physical transfer line signified by the arrow. Furthermore, arrows which do not connect two or more system components may signify a product stream which exits the depicted system or a system inlet stream which enters the depicted system. Product streams may be further processed in accompanying systems or may be commercialized as end products.

Additionally, arrows in the Figures may schematically depict process steps of transporting a stream from one system component to another system component. For example, an arrow from one system component pointing to another system component may represent "passing" a system component effluent to another system component, which may include the contents of a process stream "exiting" or being "removed" from one system component and "introducing" the contents of that product stream to another system component.

It should be understood that two or more process streams are "mixed" or "combined" when two or more lines intersect in the schematic flow diagrams of <FIG> and <FIG>. Mixing or combining may also include mixing by directly introducing both streams into a like system component, such as a vessel, reactor, separator, or other system component. For example, it should be understood that when two streams are depicted as being combined directly prior to entering a system component, the streams could equivalently be introduced into the system component and be mixed in the system component.

The present disclosure is directed to multi-functional composite catalysts and methods of preparing the composite catalysts. In particular, the composite catalyst may include a catalyst support material, zeolite particles at least partially or fully embedded within the catalyst support material, and a catalytically active compound providing catalytically active sites at outer and pore surfaces of the catalyst support material, the zeolite particles, or both. The composite catalyst of the invention is prepared according to claim <NUM>.

The composite catalyst may provide a multi-functional catalyst having multiple distinct catalytic species, each catalytic species may be capable of catalyzing a different reaction independent of the other catalytic species in the composite catalyst. For example, the composite catalyst may be useful for converting <NUM>-butene to propene through metathesis and may include the zeolite particles and a metal oxide, such as but not limited to tungsten oxide, as the catalytically active compound. The metal oxide may be catalytically active to cross-metathesize <NUM>-butene and <NUM>-butene to produce propene, pentene, and optionally other C6+ olefins. The zeolite particles may catalyze cracking of pentene or other C6+ olefins into propene and other smaller olefins during the metathesis reaction.

The composite catalyst may enable a reaction system to perform multiple catalytic reactions, such as metathesis and cracking, without requiring handling and management of multiple catalyst materials. Further, use of the composite catalyst may eliminate or reduce the need to install spacer materials in a reactor to separate catalyst beds having different catalysts. This may eliminate or reduce dead zones from a reactor. Dead zones are zones in which no reaction takes place, such as due to the presence of inert spacing materials. In some conventional reaction systems, a blend or physical mixture of two separate dry particulate catalysts may be prepared and charged to the reactor. Although a dry blend of two particulate catalysts may initially provide a multi-functional catalytic environment within a reactor system, one of the particulate catalysts may eventually settle to the bottom of the reactor under the force of gravity, which may create a separation of the two blended catalysts into separate zones in the reactor. Such separation may lead to undesirable shifts in the efficiency of the reaction system as the separate catalysts settle and develop zones within the catalyst bed with varied concentrations of the two blended catalysts. The composite catalyst described in this disclosure may reduce or eliminate the problems associated with a blended catalyst settling out in a reaction system over time.

As used in this disclosure, a "catalyst" may refer to a solid particulate that includes at least one catalytically active compound that increases the rate of a specific chemical reaction, increases the selective production of certain products in a reaction, or both.

As used through the present disclosure, the term "mesoporous" may refer to a material having an average pore size of from <NUM> nanometers (nm) to <NUM>.

As used in this disclosure, a "catalytically active compound" may refer to a substance that increases the rate of a specific chemical reaction, increases the selective production of certain products in a reaction, or both. Catalytically active compounds and the catalysts made with the catalytically active compounds described in this disclosure may be utilized to promote various reactions, such as, but not limited to, isomerization, metathesis, cracking, hydrogenation, demetalization, desulfurization, denitrogenation, other reactions, or combinations of these.

As used in this disclosure, "catalytic activity" may refer to a degree to which a catalyst or a catalytically active compound increases the reaction rate of a reaction. Greater catalytic activity of a catalyst increases the reaction rate of a reaction compared to a catalyst having a lesser catalytic activity.

As used in this disclosure, a "stable" mixture refers to a solids-liquid mixture in which the liquid portion includes dissolved solids that do not precipitate out of the liquid portion. The dissolved solids in the liquid portion of a stable mixture, for example, will not precipitate out during later processing steps of the method disclosed herein.

As used throughout the present disclosure, the term "butene" or "butenes" may refer to compositions comprising one or more than one of <NUM>-butene, trans-<NUM>-butene, cis-<NUM>-butene, isobutene, or mixtures of these isomers. As used throughout the present disclosure, the term "normal butenes" may refer to compositions comprising one or more than one of <NUM>-butene, trans-<NUM>-butene, cis-<NUM>-butene, or mixtures of these isomers, and does not include isobutene. As used throughout the present disclosure, the term "<NUM>-butene" may refer to trans-<NUM>-butene, cis-<NUM>-butene, or a mixture of these two isomers.

As previously discussed, the composite catalyst may be a spray dried catalyst that includes zeolite particles at least partially or fully surrounded by or embedded within agglomerates formed of the catalyst support material and at least one catalytically active compound deposited on surfaces of the catalyst support material, the zeolite particles, or both. The agglomerates of the catalyst support material and zeolite particles may be formed by agglomeration of the catalyst support material during spray drying. The catalyst support material may be an oxide of a metal or metalloid, such as an oxide of one or more of silicon, aluminum, titanium, cerium, or combinations of these. The catalyst support material may be silica, fumed silica, alumina, fumed alumina, titania, fumed titania, ceria, fumed ceria, or combinations of these.

In one or more embodiments, the catalyst support material may be silica. Examples of silica catalyst support materials suitable for use in preparing the composite catalyst may include mesoporous silica supports. The mesoporous silica supports may have an average pore diameter from <NUM> nanometers (nm) to <NUM> and a total pore volume of at least <NUM> milliliter per gram (mL/g). In one or more embodiments, silica of the catalyst support material may have an average pore diameter of from <NUM> to <NUM>, or from <NUM> to <NUM>, or from <NUM> to <NUM>, or from <NUM> to <NUM>, or from <NUM> to <NUM>, or from <NUM> to <NUM>. The silica supports suitable for the catalyst support material may have a total pore volume of from <NUM>/g to <NUM>/g, or from <NUM>/g to <NUM>/g, or from <NUM>/g to <NUM>/g, or from <NUM>/g to <NUM>/g, or from <NUM>/g to <NUM>/g, or from <NUM>/g to <NUM>/g. Silica supports suitable for the catalyst support material may have a surface area of from <NUM> square meters per gram (m<NUM>/g) to <NUM><NUM>/g. The silica supports may have a surface area of from <NUM><NUM>/g to <NUM><NUM>/g, or from <NUM><NUM>/g to <NUM><NUM>/g, or from <NUM><NUM>/g to <NUM><NUM>/g, or from <NUM><NUM>/g to <NUM><NUM>/g.

In one or more than one embodiments, the silica supports may be substantially free of extraneous metals or elements which might adversely affect the catalytic activity of the system. As used in the present disclosure, the term "substantially free" of a component may refer to a composition, such as a catalyst support material, zeolite, catalyst or catalyst precursor mixture, having less than <NUM> weight percent (wt. %) of that component in the composition. For example, the silica supports that are substantially free of extraneous metals or elements may contain less than <NUM> wt. % of these extraneous metals or elements. One suitable silica support may be the Santa Barbara Amorphous (SBA-<NUM>) mesoporous silica molecular sieve. Alternatively, another suitable example of a silica support may be the CARiACT® silica support (commercially available from Fuji Silysia Chemical Ltd, headquartered in Aichi, Japan). In one or more embodiments, catalyst support material can be CARiACT® Grade Q-<NUM> silica support particles having an average pore diameter of <NUM>, a pore volume of <NUM>/g, a surface area of <NUM><NUM>/g, and an average particle size of from <NUM> micrometers (µm) to <NUM>. In one or more embodiments, the catalyst support material can be CARiACT® Grade Q-<NUM> silica particles with average particle sizes of from <NUM> to <NUM>.

The composite catalyst and methods of making the composite catalyst of the present disclosure utilize preformed catalyst support particles, such as silica or other metal oxide particles, for the catalyst support material instead of other sources of catalyst supports. Thus, the methods of the present disclosure for preparing the composite catalysts may not include the step of forming the catalyst support materials from one or more precursors, such as preparing silica from one or more silica precursors, prior to spray drying, during the spray drying process, or during an additional calcination step. The initial provision of the preformed catalyst support material with optimal properties of surface area, pore diameter, and pore volume leads to the reliable formation of a uniform catalyst composition. The use of silicon dioxide precursors, such as tetraethyl orthosilicate, requires additional steps of formation of SiO<NUM> in the spray dryer and does not result in uniform support structures. Additionally, when silica precursors are used, at least a portion of the catalytically active compound precursor may be trapped within the silica rather than being deposited on the surfaces of the silica, which can render this portion of the catalytically active compounds unusable and can increase the amount of the expensive catalytically active compound precursors required. Thus, the propylene selectivity and yield in the metathesis reactions are affected.

The composite catalyst may include an amount of the catalyst support material sufficient to form agglomerates that partially or fully surround and entrap the zeolite particles within the agglomerates of the catalyst support material. The composite catalyst may have from <NUM> wt. % to <NUM> wt. % catalyst support material based on the total weight of the composite catalyst. The composite catalyst may include from <NUM> wt. % to <NUM> wt. %, from <NUM> wt. % to <NUM> wt. %, from <NUM> wt. % to <NUM> wt. %, from <NUM> wt. % to <NUM> wt. %, from <NUM> wt. % to <NUM> wt. %, from <NUM> wt. % to <NUM> wt. %, from <NUM> wt. % to <NUM> wt. %, from <NUM> wt. % to <NUM> wt. %, from <NUM> wt. % to <NUM> wt. %, from <NUM> wt. % to <NUM> wt. %, from <NUM> wt. % to <NUM> wt. %, from <NUM> wt. % to <NUM> wt. %, from <NUM> wt. % to <NUM> wt. %, from <NUM> wt. % to <NUM> wt. %, from <NUM> wt. % to <NUM> wt. %, from <NUM> wt. % to <NUM> wt. %, from <NUM> wt. % to <NUM> wt. %, or from <NUM> wt. % to <NUM> wt. % catalyst support material based on the total weight of the composite catalyst.

As previously discussed, the composite catalyst may further include zeolite particles that are at least partially or fully surrounded by or embedded in the catalyst support material. The zeolite particles may include one or more than one zeolite composition. As used in the present disclosure, a zeolite composition refers to a zeolite with a particular zeolitic framework structure and having a particular material composition. Thus, zeolite compositions may differ between one another by framework structure, composition, or both. Zeolite compositions may be grouped into "zeolite types" such as MFI framework type zeolites (such as ZSM-<NUM> zeolite), FAU framework type zeolites (such as Y zeolite), or *BEA framework type zeolites (such as zeolite Beta), each of which is described subsequently in this disclosure. Other zeolite types having other framework types and compositions may also be used to produce the composite catalyst.

In one or more embodiments, the zeolite particles may comprise one or more MFI framework type zeolites, such as ZSM-<NUM>. As used in the present disclosure, "ZSM-<NUM>" refers to zeolites having an MFI framework type according to the International Union of Pure and Applied Chemistry (IUPAC) zeolite nomenclature and consisting of silica and alumina. ZSM-<NUM> refers to "Zeolite Socony Mobil-<NUM>" and is a pentasil family zeolite that can be represented by the chemical formula NanAlnSi<NUM>-nO<NUM>·<NUM><NUM>O, where <NUM><n<<NUM>. Examples of commercially available zeolite ZSM-<NUM> may include but are not limited to CBV2314, CBV3024E, CBV5524G and CBV28014 (available from Zeolyst International). The MFI framework type zeolite may comprise one or more phosphorous-containing compounds, such as a phosphorous oxide, such as phosphorous pentoxide ("P<NUM>O<NUM>").

In one or more embodiments, the catalyst composition may comprise a FAU framework type zeolite, such as zeolite Y. As used in this disclosure, "zeolite Y" refers to zeolite having a FAU framework type according to the IUPAC zeolite nomenclature and consisting of silica and alumina, where the molar ratio of silica to alumina is at least <NUM>. For example, the molar ratio of silica to alumina in the zeolite Y may be at least <NUM>, at least <NUM>, or even at least <NUM>, such as from <NUM> to <NUM>, from <NUM> to <NUM>, or from about <NUM> to about <NUM>. The unit cell size of the zeolite Y may be from about <NUM> Angstrom to about <NUM> Angstrom, such as <NUM> Angstrom.

In one or more embodiments, the catalyst composition may comprise one or more *BEA framework type zeolites, such as zeolite Beta. As used in this disclosure, "zeolite Beta" refers to zeolite having a *BEA framework type according to the IUPAC zeolite nomenclature and consisting of silica and alumina. The molar ratio of silica to alumina in the zeolite Beta may be at least <NUM>, at least <NUM>, or even at least <NUM>. For example, the molar ratio of silica to alumina in the zeolite Beta may be from <NUM> to <NUM>, such as from <NUM> to <NUM>. Examples of commercially available zeolite Beta compositions may include, but are not limited to, CP814C, CP814E and CP811C-<NUM> (produced by Zeolyst International). The zeolite Beta may be in the form of H-Beta. H-Beta refers to the acidic form of zeolite Beta usually derived from ammonium-Beta (NH<NUM>-Beta) via calcination. In one or more embodiments, the zeolite Beta may be stabilized by direct reaction with phosphoric acid (H<NUM>PO<NUM>) or by impregnation with ammonium hydrogen phosphate ((NH<NUM>)<NUM>HPO<NUM>). According to one or more embodiments, the *BEA framework type zeolite may comprise one or more phosphorous-containing compounds, such as a phosphorous oxide or phosphorous pentoxide ("P<NUM>O<NUM>").

The zeolite particles may have a weight ratio of silica to alumina of from <NUM>:<NUM> to <NUM>:<NUM>. For example, the zeolite may have a weight ratio of silica to alumina of from <NUM>:<NUM> to <NUM>:<NUM>, from <NUM>:<NUM> to <NUM>:<NUM>, from <NUM>:<NUM> to <NUM>:<NUM>, from <NUM>:<NUM> to <NUM>:<NUM>, from <NUM>:<NUM> to <NUM>:<NUM>, from <NUM>:<NUM> to <NUM>:<NUM>, from <NUM>:<NUM> to <NUM>:<NUM>, from <NUM>:<NUM> to <NUM>:<NUM>, from <NUM>:<NUM> to <NUM>:<NUM>, from <NUM>:<NUM> to <NUM>:<NUM>, from <NUM>:<NUM> to <NUM>:<NUM>, from <NUM>:<NUM> to <NUM>:<NUM>, from <NUM>:<NUM> to <NUM>:<NUM>, from <NUM>:<NUM> to <NUM>:<NUM>, from <NUM>:<NUM> to <NUM>:<NUM>, from <NUM>:<NUM> to <NUM>:<NUM>, from <NUM>:<NUM> to <NUM>:<NUM>, from <NUM>:<NUM> to <NUM>:<NUM>, from <NUM>:<NUM> to <NUM>:<NUM>, from <NUM>:<NUM> to <NUM>:<NUM>, from <NUM>:<NUM> to <NUM>:<NUM>, or from <NUM>:<NUM> to <NUM>:<NUM>, based on the total weight of the zeolite. In one or more embodiments, the zeolite particles may be an MFI <NUM> zeolite cracking catalyst having a weight ratio of silica to alumina of <NUM>:<NUM>.

The zeolite particles may have an average particle size less than the average particle size of the composite catalyst. The zeolite particles may have an average particle size of less than or equal to <NUM>, less than or equal to <NUM>, less than or equal to <NUM>, or even less than or equal to <NUM>. The zeolite particles may have an average particle size of greater than or equal to <NUM>, greater than or equal to <NUM>, or even greater than or equal to <NUM>. The zeolite particles may have an average particle size of from <NUM> to <NUM>, from <NUM> to <NUM>, from <NUM> to <NUM>, from <NUM> to <NUM>, from <NUM> to <NUM>, from <NUM> to <NUM>, from <NUM> to <NUM>, from <NUM> to <NUM>, from <NUM> to <NUM>, from <NUM> to <NUM>, from <NUM> to <NUM>, from <NUM> to <NUM>, from <NUM> to <NUM>, or even from <NUM> to <NUM>.

The composite catalyst may include an amount of the zeolite particles sufficient to catalyst cracking reactions during metathesis of butene to produce propene and other light olefins. The composite catalyst may include from <NUM> wt. % to <NUM> wt. % zeolite particles based on the total weight of the composite catalyst. The composite catalyst may include from <NUM> wt. % to <NUM> wt. %, from <NUM> wt. % to <NUM> wt. %, from <NUM> wt. % to <NUM> wt. %, from <NUM> wt. % to <NUM> wt. %, from <NUM> wt. % to <NUM> wt. %, from <NUM> wt. % to <NUM> wt. %, from <NUM> wt. % to <NUM> wt. %, from <NUM> wt. % to <NUM> wt. %, or from <NUM> wt. % to <NUM> wt. % zeolite particles based on the total weight of the composite catalyst.

In some embodiments, the composite catalyst particles of the present disclosure may be agglomerations of the catalyst support material and the zeolite particles. For example, the catalyst support material and zeolite particles may form agglomerates in which the zeolite particles are at least partially or fully embedded in the catalyst support material. Additionally, a catalytically active compound may be deposited on surfaces throughout the composite catalyst particles and may produce catalytically active sites at outer surfaces and pore surfaces of the catalyst support material, the zeolite particles, or both.

As previously described, the composite catalyst may have at least one catalytically active compound supported by the catalyst support material, the zeolite particles, or both. The catalytically active compound is different from the zeolite particles and the catalyst support material. The catalytically active compounds may include compounds that have catalytic activity to promote metathesis reactions, isomerization reactions, or both. The catalytically active compounds may also be functional to remove contaminants and catalyst poisons from a reactant stream. The catalytically active compounds may include a metathesis catalyst. In one or more embodiments, the catalytically active compounds may include an isomerization catalyst.

The catalytically active compound may be a metal, metal oxide, other catalytically active compound, or combinations of these. The catalytically active compound may be a metal, such as but not limited to platinum, gold, palladium, rhodium, iridium, chromium, other metal, or combinations of these. The catalytically active compound may include a metal oxide, such as one or more than one oxide of a metal from Groups <NUM>-<NUM> of the International Union of Pure and Applied Chemistry Periodic Table of the Elements (IUPAC periodic table). The metal oxide may include at least one oxide of molybdenum, rhenium, tungsten, manganese, titanium, cerium, or any combination of these. In some embodiments, the metal oxide may be tungsten oxide. The morphology, type, and amount of the catalytically active compound deposited on the surface of the catalyst support may determine the catalytic activity of the composite catalyst.

The composite catalyst may include one or a plurality of catalytically active compounds supported by the catalyst support material, the zeolite particles, or both. For example, the composite catalyst may include <NUM>, <NUM>, <NUM>, <NUM>, <NUM>, <NUM>, or more than <NUM> catalytically active compounds. Theoretically, the number of different catalytically active compounds that can be incorporated into the composite catalyst may be unlimited. However, the number of different catalytically active compounds that can be included in the composite catalyst may be limited by the type of reactions that can be conducted simultaneously. The number of different catalytically active compounds may also be limited by reactions that must be conducted sequentially. The number of different catalytically active compounds may also be limited by catalyst poisoning considerations.

The catalytically active compounds may be disposed at the surfaces of the composite catalyst that are accessible to vapors and gases, such as being deposited on the outer surfaces and pore surfaces of the composite catalyst. The catalytically active compounds may be deposited on the outer surfaces or pore surfaces of the catalyst support material, the zeolite particles, or both. The catalytically active compounds may provide catalytically active sites at the surfaces of the composite catalyst, such as the outer surfaces, pore surfaces, or both.

The composite catalyst may have an amount of the catalytically active compounds sufficient for the composite catalyst to exhibit the functionality of the catalytically active compound. For example, the catalytically active compound may be tungsten oxide, and the composite catalyst may include an amount of the tungsten oxide sufficient to catalyze olefin metathesis reactions. The composite catalyst may include from <NUM> wt. % to <NUM> wt. % catalytically active compound based on the total weight of the composite catalyst. The composite catalyst may have from <NUM> wt. % to <NUM> wt. %, from <NUM> wt. % to <NUM> wt. %, from <NUM> wt. % to <NUM> wt. %, from <NUM> wt. % to <NUM> wt. %, from <NUM> wt. % to <NUM> wt. %, from <NUM> wt. % to <NUM> wt. %, from <NUM> wt. % to <NUM> wt. %, from <NUM> wt. % to <NUM> wt. %, from <NUM> wt. % to <NUM> wt. %, from <NUM> wt. % to <NUM> wt. %, from <NUM> wt. % to <NUM> wt. %, from <NUM> wt. % to <NUM> wt. %, from <NUM> wt. % to <NUM> wt. %, from <NUM> wt. % to <NUM> wt. %, from <NUM> wt. % to <NUM> wt. %, from <NUM> wt. % to <NUM> wt. %, from <NUM> wt. % to <NUM> wt. %, from <NUM> wt. % to <NUM> wt. %, from <NUM> wt. % to <NUM> wt. %, or from <NUM> wt. % to <NUM> wt. % catalytically active compound based on the total weight of the composite catalyst.

The composite catalysts of the present disclosure may be synthesized through a spray drying process. In the spray drying process, a catalyst precursor mixture may be prepared and then introduced to a spray dryer. The catalyst precursor mixture may prepared by combining the zeolite particles, the catalyst support material, a catalytically active compound precursor, a surfactant, and at least one diluent to form a catalyst precursor composition and then mixing the catalyst precursor composition to produce the catalyst precursor mixture. The zeolite particles may be any of the zeolites previously described in the present disclosure. For example, in one or more embodiments, the zeolite particles may be ZSM-<NUM> zeolite particles. The catalyst precursor mixture may include from <NUM> weight percent (wt. %) to <NUM> wt. % zeolite particles based on the dry weight of the catalyst precursor mixture. As used throughout the present disclosure, the "dry weight" of the catalyst precursor mixture refers to the total weight of the catalyst precursor mixture minus the total weight of diluents in the catalyst precursor mixture.

The catalyst support material may be any of the catalyst support materials previously described in the present disclosure. For example, in one or more embodiments, the catalyst support material may include one or more of silica, alumina, titania, ceria, or combinations of these. In one or more embodiments, the catalyst support material may be silica supports, such as preformed silica support particles, which may have any of the features, characteristics, or properties previously described for the silica supports. The catalyst precursor mixture may include from <NUM> wt. % to <NUM> wt. % catalyst support material based on the dry weight of the catalyst precursor mixture. Again, dry weight refers to the weight of the catalyst precursor mixture <NUM> without the diluent. For example, in some embodiments, the catalyst precursor mixture <NUM> may include from <NUM> wt. % to <NUM> wt. %, from <NUM> wt. % to <NUM> wt. %, from <NUM> wt. % to <NUM> wt. %, from <NUM> wt. % to <NUM> wt. %, from <NUM> wt. % to <NUM> wt. %, from <NUM> wt. % to <NUM> wt. %, from <NUM> wt. % to <NUM> wt. %, from <NUM> wt. % to <NUM> wt. %, from <NUM> wt. % to <NUM> wt. %, from <NUM> wt. % to <NUM> wt. %, from <NUM> wt. % to <NUM> wt. %, from <NUM> wt. % to <NUM> wt. %, from <NUM> wt. % to <NUM> wt. %, from <NUM> wt. % to <NUM> wt. %, from <NUM> wt. % to <NUM> wt. %, from <NUM> wt. % to <NUM> wt. %, from <NUM> wt. % to <NUM> wt. %, or from <NUM> wt. % to <NUM> wt. % catalyst support material based on the dry weight of the catalyst precursor mixture.

The catalytically active compound precursor may be a metal, such as platinum, gold, palladium, rhodium, iridium, chromium, other metal, or combinations of these. Alternatively or additionally, the catalytically active compound precursors may include a metal salt that can be solubilized in the diluent. The catalytically active compound precursors may include an oxometallate precursor. The oxometallate precursor may be a metal oxide precursor of one or more oxides of a metal from the Groups <NUM>-<NUM> of the IUPAC Periodic Table. The metal oxide may be at least one oxide of molybdenum, rhenium, tungsten, manganese, titanium, cerium, or any combination of these. Alternatively, the oxometallate precursor may be a tungstate precursor. Examples of tungstate precursors may include, but are not limited to, ammonium metatungstate ((NH<NUM>)<NUM>H<NUM>W<NUM>O<NUM>), ammonium paratungstate, tungstic acid, phosphotungstic acid, sodium tungstate, other tungstate precursor, or combinations of these. In one or more embodiments, the tungstate precursor may comprise ammonium metatungstate, ammonium metatungstate hexahydrate, or ammonium paratungstate. In one or more embodiments, the oxometallate precursor may be a tungsten oxide, such as tungsten (IV) oxide, tungsten (VI) oxide, other tungsten oxides, or combinations of tungsten oxides. In one or more embodiments, the metal oxide is tungsten oxide (WO<NUM>). The catalyst precursor mixture may include a plurality of catalytically active compound precursors to produce a composite catalyst having a plurality of catalytically active compounds deposited on the outer and pore surfaces of the catalyst support material, zeolite particles, or both.

The catalyst precursor mixture may include from <NUM> wt. % to <NUM> wt. % catalytically active compound precursors, based on the dry weight of the catalyst precursor mixture. The catalyst precursor mixture may include from <NUM> wt. % to <NUM> wt. %, from <NUM> wt. % to <NUM> wt. %, from <NUM> wt. % to <NUM> wt. %, from <NUM> wt. % to <NUM> wt. %, from <NUM> wt. % to <NUM> wt. %, from <NUM> wt. % to <NUM> wt. %, from <NUM> wt. % to <NUM> wt. %, from <NUM> wt. % to <NUM> wt. %, from <NUM> wt. % to <NUM> wt. %, from <NUM> wt. % to <NUM> wt. %, from <NUM> wt. % to <NUM> wt. %, from <NUM> wt. % to <NUM> wt. %, from <NUM> wt. % to <NUM> wt. %, from <NUM> wt. % to <NUM> wt. %, from <NUM> wt. % to <NUM> wt. %, from <NUM> wt. % to <NUM> wt. %, from <NUM> wt. % to <NUM> wt. %, from <NUM> wt. % to <NUM> wt. %, from <NUM> wt. % to <NUM> wt. %, or from <NUM> wt. % to <NUM> wt. % catalytically active compound precursors, based on the dry weight of the catalyst precursor mixture.

A polymeric surfactant may be included in the catalyst precursor mixture to enhance the dispersion of the catalytically active compound precursor in the catalyst precursor mixture, resulting in improved distribution of the catalytically active compound on the surfaces of the catalyst support material, zeolite particles, or both. The surfactant may be a symmetric triblock copolymer surfactant, such as the Pluronic® P123 surfactant (available from BASF Corporation, headquartered in Florham Park, N. , USA), which is a poly(ethylene glycol)-block-poly(propylene glycol)-block-poly(ethylene glycol) copolymer (PEG-PPG-PEG copolymer). The triblock copolymer, PEG-PPG-PEG, comprises of poly(ethylene oxide)(PEO) and poly (propylene oxide)(PPO) comonomers and exhibits hydrophobicity at temperatures above <NUM> Kelvin and solubility in water at temperatures below <NUM> Kelvin. This dual characteristic leads to formation of micelles including of PEG-PPG-PEG triblock copolymers. Dissolved Pluronic® P123 surfactant forms micelles that are used as the backbone to make structured mesoporous silica such as SBA-<NUM>. In contrast, disclosed here are uses of the triblock copolymer to facilitate the deposition of the catalytically active compound, such as tungsten oxide, on the catalyst support material. In a conventional synthesis, the surfactant is added to a metal precursor and this mixture is subject to thermal treatment. The metal precursor decomposes to generate a metal oxide. In the methods and compositions of the present disclosure, the surfactant may be used to enhance the mixing between the catalyst support material, such as a silica support, and the catalytically active compound precursor, such as tungsten precursor, in the catalyst precursor mixture. The enhanced mixing provided by the surfactant may improve the distribution of the catalytically active compound (such as tungsten oxide) on the surfaces of the catalyst support material and zeolite particles, upon thermal treatment. Surfactant properties, such as whether the surfactant is ionic, cationic, or nonionic, play a role in the effectiveness of a polymeric surfactant. The use of a triblock copolymer enables an easy and reliable large-scale method of preparation of the composite catalysts of the present disclosure.

The catalyst precursor mixture may have an amount of surfactant sufficient to evenly disperse the catalytically active compound precursor throughout the catalyst precursor mixture. The catalyst precursor mixture may include from <NUM> wt. % to <NUM> wt. % surfactant based on the dry weight of the catalyst precursor mixture. The catalyst precursor mixture may include from <NUM> wt. % to <NUM> wt. %, from <NUM> wt. % to <NUM> wt. %, from <NUM> wt. % to <NUM> wt. %, from <NUM> wt. % to <NUM> wt. %, from <NUM> wt. % to <NUM> wt. %, from <NUM> wt. % to <NUM> wt. %, from <NUM> wt. % to <NUM> wt. %, from <NUM> wt. % to <NUM> wt. %, from <NUM> wt. % to <NUM> wt. %, from <NUM> wt. % to <NUM> wt. %, from <NUM> wt. % to <NUM> wt. %, or from <NUM> wt. % to <NUM> wt. % surfactant based on the dry weight of the catalyst precursor mixture.

The diluent may be water, an organic solvent, or a combination of water and at least one organic solvent. Example organic solvents may include methanol, ethanol, acetone, or a combination of solvents. In one or more embodiments, the diluent may be water such that the catalyst precursor mixture is an aqueous catalyst precursor mixture. The diluent may also include water in combination with an alcohol, such as ethanol, which may improve the ability to dissolve the triblock copolymer surfactant in the diluent during preparation of the catalyst precursor mixture. The catalyst precursor mixture may have an amount of the diluent sufficient to atomize the catalyst precursor mixture in the spray dryer. The catalyst precursor mixture may have an amount of diluent sufficient to produce a desired average particle size of the composite catalyst particles made by the spray drying process. For example, increasing the amount of diluent may decrease the average particle size of the composite catalyst due to the decreased concentration of the catalyst support material, zeolite particles, catalytically active compound precursor, and surfactant in each of the droplets. The catalyst precursor mixture may include from <NUM> wt. % to <NUM> wt. % diluent based on the total weight of the catalyst precursor mixture. For example, the catalyst precursor mixture may include from <NUM> wt. % to <NUM> wt. %, from <NUM> wt. % to <NUM> wt. %, from <NUM> wt. % to <NUM> wt. %, from <NUM> wt. % to <NUM> wt. %, from <NUM> wt. % to <NUM> wt. %, from <NUM> wt. % to <NUM> wt. %, from <NUM> wt. % to <NUM> wt. %, or from <NUM> wt. % to <NUM> wt. % diluent based on the total weight of the catalyst precursor mixture.

Referring to <FIG>, the catalyst precursor mixture, designated in <FIG> by reference number <NUM>, may be prepared by combining the catalyst support material, the zeolite particles, the catalytically active compound precursor, the triblock copolymer surfactant, and the diluent to form a catalyst precursor composition and then mixing the catalyst precursor composition to produce the catalyst precursor mixture. The catalyst precursor composition may be prepared through one or a plurality of mixing processes. Preparation of the catalyst precursor mixture <NUM> may include a first mixing process <NUM> that may include combining the zeolite particles <NUM>, the catalyst support material <NUM>, and a first portion <NUM> of the diluent to produce a first mixture <NUM>. The first mixing process <NUM> may further include mixing the first mixture <NUM> under conditions sufficient to disperse the solid zeolite particles and solid catalyst support materials in the diluent. The first mixing process <NUM> may be conducted in a vessel having a mixer or agitator. In one or more embodiments, the vessel may be a feed vessel for the spray dryer <NUM>. The first mixture <NUM> may be mixed at a rotational speed of greater than or equal to <NUM> rotations per minute (rpm), greater than or equal to <NUM> rpm, or even greater than or equal to <NUM> rpm, such as from <NUM> rpm to <NUM> rpm. The first mixture <NUM> may be mixed for at least <NUM> minutes, such as from <NUM> minutes to <NUM> hours.

Preparation of the catalyst precursor mixture <NUM> may include a second mixing process <NUM>, in which the surfactant <NUM>, such as the triblock copolymer surfactant, may be combined with a second portion <NUM> of the diluent and mixed until the surfactant is completely dissolved in the diluent to produce a second mixture <NUM>. When the surfactant is a triblock copolymer surfactant, the second portion <NUM> of the diluent may include an alcohol <NUM>, such as ethanol for example, which may be added to the second portion <NUM> of the diluent. The ethanol <NUM> may assist in dissolving the surfactant <NUM> to form a homogeneous second mixture <NUM>. The second mixture <NUM> may be prepared in a vessel having a mixer or agitator and may be mixed under conditions sufficient to completely dissolve the surfactant <NUM> in the diluent. For example, the second mixture <NUM> may be mixed at a rotational speed of greater than or equal to <NUM> rpm, greater than or equal to <NUM> rpm, or greater than or equal to <NUM> rpm, such as from <NUM> rpm to <NUM> rpm or from <NUM> rpm to <NUM> rpm. The second mixture <NUM> may be mixed for a time period of at least <NUM> minutes, such as from <NUM> minutes to <NUM> hours.

Preparation of the catalyst precursor mixture <NUM> may further include a third mixing process <NUM>, in which at least one catalytically active compound precursor <NUM> may be combined with a third portion <NUM> of the diluent, such as water, and mixed until the catalytically active compound precursor <NUM> completely dissolves in the third portion <NUM> of the diluent to produce a third mixture <NUM>. The third mixture <NUM> may be prepared in a vessel having a mixer or agitator and may be mixed under conditions sufficient to completely dissolve the catalytically active compound precursor <NUM> in the diluent. For example, the third mixture <NUM> may be mixed at a rotational speed of greater than or equal to <NUM> rpm, greater than or equal to <NUM> rpm, or greater than or equal to <NUM> rpm, such as from <NUM> rpm to <NUM> rpm or from <NUM> rpm to <NUM> rpm. The third mixture <NUM> may be mixed for a time period of at least <NUM> minutes, such as from <NUM> minutes to <NUM> hours.

Referring still to <FIG>, preparation of the catalyst precursor mixture <NUM> may include combing the second mixture <NUM> and the third mixture <NUM> to produce a fourth mixture <NUM> that includes the surfactant <NUM> and the at least one catalytically active compound precursor <NUM> dissolved in the diluent. The fourth mixture <NUM> may be mixed under conditions sufficient to produce a homogeneous mixture of the surfactant and catalytically active compound precursor.

The fourth mixture <NUM> may be added to the first mixture <NUM>, which includes the zeolite particles and catalyst support material dispersed in the diluent to produce the catalyst precursor composition. The fourth mixture <NUM> and first mixture <NUM> may be combined in the feed vessel <NUM> of the spray dryer <NUM>. The catalyst precursor composition may be mixed to produce the catalyst precursor mixture <NUM> in which the catalyst support material and the zeolite particles are suspended in the diluent and do not precipitate or settle out of the catalyst precursor mixture <NUM> during spray drying. The catalyst precursor composition may be mixed under conditions sufficient to reduce or prevent precipitation or settling of the catalyst support material, zeolite particles, or both, during spray drying. The catalyst precursor composition may be mixed at a rotational speed of up to <NUM> rpm, such as from <NUM> rpm to <NUM> rpm. The catalyst precursor composition may be mixed for a period of time sufficient to produce the catalyst precursor mixture which may be a colloidal mixture in which the catalyst support particles, zeolite particles, or both do not precipitate or settle out during spray drying. The catalyst precursor composition may be mixed for a period of time greater than or equal to <NUM> hours, such as from <NUM> hours to <NUM> hours or from <NUM> hours to <NUM> hours to produce the catalyst precursor mixture <NUM>. After mixing, the catalyst precursor mixture <NUM> may be colloidal solution, which may be a stable mixture. In other words, after mixing, the catalyst precursor mixture <NUM> may be a homogeneous colloidal mixture that may have a reduced propensity for solids dropping out of solution and settling compared to the catalyst precursor composition before mixing. When the mixing time is less than <NUM> hours, the catalyst precursor mixture <NUM> may not form a stable colloidal solution and may exhibit settling of the catalyst support material during spray drying, which may adversely affect the composite catalyst produced by the process. This settling may affect the efficiency of the spray drying process, which may decrease the product yield when the composite catalyst is used in a metathesis process.

The catalyst precursor mixture <NUM> may include from <NUM> wt. % to <NUM> wt. % catalyst support material <NUM>, from <NUM> wt. % to <NUM> wt. % zeolite particles <NUM>, from <NUM> wt. % to <NUM> wt. % surfactant, and from <NUM> wt. % to <NUM> wt. % catalytically active compound precursors, based on the dry weight of the catalyst precursor mixture. The catalyst precursor mixture <NUM> may have an amount of solids of from <NUM> wt. % to <NUM> wt. %, from <NUM> wt. % to <NUM> wt. %, from <NUM> wt. % to <NUM> wt. %, from <NUM> wt. % to <NUM> wt. %, from <NUM> wt. % to <NUM> wt. %, from <NUM> wt. % to <NUM> wt. %, from <NUM> wt. % to <NUM> wt. %, from <NUM> wt. % to <NUM> wt. %, from <NUM> wt. % to <NUM> wt. %, from <NUM> wt. % to <NUM> wt. %, from <NUM> wt. % to <NUM> wt. %, from <NUM> wt. % to <NUM> wt. %, or from <NUM> wt. % to <NUM> wt. % based on the total weight of the catalyst precursor mixture <NUM>, where the solids comprise the zeolite particles, catalyst support material, catalytically active compound precursor, and copolymer surfactant (everything but the diluents).

Referring again to <FIG>, the catalyst precursor mixture <NUM> may be spray dried in a spray dryer <NUM> to produce the composite catalyst. The spray dryer <NUM> may be any commercially-available spray dryer system. The spray dryer <NUM> may include a drying chamber <NUM> that includes a cylindrical portion <NUM> and a conical portion <NUM>. The spray dryer <NUM> may also include a spray nozzle <NUM> disposed within the drying chamber <NUM> and operable to atomize the catalyst precursor solution <NUM> within the drying chamber <NUM>. A heated gas <NUM> may be introduced to the drying chamber <NUM>. The gas may be air or an inert gas, such as but not limited to nitrogen, helium, argon, or other inert gas. Additionally, water <NUM> may be fluidly coupled to the spray nozzle <NUM> for use during start-up of the spray dryer <NUM>. The catalyst precursor mixture <NUM> may be heated to a spraying temperature prior to introducing the catalyst precursor mixture <NUM> to the spray nozzle <NUM>. The spraying temperature of the catalyst precursor mixture <NUM> may be greater than or equal to <NUM>, greater than or equal to <NUM>, or even greater than or equal to <NUM>. The spraying temperature of the catalyst precursor mixture may be from <NUM> to <NUM>, from <NUM> to <NUM>, from <NUM> to <NUM>, from <NUM> to <NUM>, from <NUM> to <NUM>, or even from <NUM> to <NUM>. If the spraying temperature is too low, evaporation of the diluent from the droplets of catalyst precursor mixture <NUM> in the drying chamber <NUM> may be insufficient at the surface temperature of the drying chamber <NUM>. If the spraying temperature is too high, evaporation of the diluent may be too rapid, resulting in reduced cohesion within the composite catalyst, which can influence the durability of the composite catalyst.

During steady-state operation of the spray dryer <NUM>, the catalyst precursor mixture <NUM> may be delivered to the spray nozzle <NUM> by catalyst precursor pump <NUM>. The spray nozzle <NUM> may atomize the catalyst precursor mixture <NUM> into a plurality of droplets of the catalyst precursor mixture <NUM>. The type of spray nozzle <NUM> may influence the average droplet size of the droplets of catalyst precursor mixture <NUM> in the drying chamber <NUM>, which may influence the average particle size of the composite catalyst recovered from the spray dryer <NUM>. For example, a spray nozzle <NUM> configured to produce smaller-sized droplets may produce composite catalysts having a smaller average particle size. Additionally, the pressure, flowrate, or both, of the catalyst precursor mixture <NUM> delivered to the spray nozzle <NUM> may also influence the droplet size and the average particle size of the composite catalyst.

Referring to <FIG>, the droplets of the catalyst precursor mixture <NUM> are atomized into the spray drying chamber <NUM>, where the droplets are heated by the heated gas <NUM>. The drying chamber <NUM> of the spray dryer <NUM> may be maintained at a surface temperature sufficient to vaporize the diluent <NUM> from the droplets of the catalyst precursor mixture <NUM> to form a plurality of solid composite catalyst particles. The surface temperature of the drying chamber <NUM> refers to the temperature measured at the interior surface of the drying chamber <NUM>. The heated gas <NUM> may be heated to a temperature sufficient to maintain the surface temperature of the drying chamber <NUM>. The drying chamber <NUM> may be maintained at a surface temperature of from <NUM> to <NUM>, such as from <NUM> to <NUM>, from <NUM> to <NUM>, from <NUM> to <NUM>, from <NUM> to <NUM>, from <NUM> to <NUM>, from <NUM> to <NUM>, from <NUM> to <NUM>, from <NUM> to <NUM>, from <NUM> to <NUM>, from <NUM> to <NUM>, or from <NUM> to <NUM>. If the surface temperature of the drying chamber is too low, then the diluent in the droplets of catalyst precursor mixture <NUM> may not completely vaporize to produce the solid composite catalyst particles.

In the drying chamber <NUM>, heat from the heated gas <NUM> may cause removal of the diluents from the droplets of the catalyst precursor mixture <NUM>, such as by vaporization of the diluents. As the diluent vaporizes from the droplets of the catalyst precursor mixture <NUM>, the volume of each of the droplets of the catalyst precursor mixture <NUM> may decrease, and the catalyst support material of the catalyst support precursor <NUM> may converge to form agglomerates that may at least partially or fully surround and secure or trap the zeolite particles within the catalyst support material to form the composite catalyst particles.

As the diluent is removed, the catalytically active compound precursor may deposit onto the surfaces of the catalyst support material, the zeolite particle, or both. The triblock copolymer surfactant in the catalyst precursor mixture may operate to space apart the catalytically active compound precursor and prevent consolidation of the catalytically active compound precursor into larger crystals or agglomerates during the drying process. This may enable the catalytically active compound precursor to be more evenly distributed across the surfaces (outer and pore surfaces) of the catalyst support material, zeolite particles, or both. As the diluent is removed from the droplets of the catalyst precursor mixture <NUM> in the drying chamber <NUM>, the catalytically active compound precursor depositing on the surfaces of the catalyst support material, zeolite particles, or both may undergo chemical reaction to transition from the catalytically active compound precursor into the catalytically active compound. For example, a catalytically active compound precursor comprising a tungsten compound, such as ammonium metatungstate, may undergo oxidation at the temperatures in the drying chamber <NUM> to convert the tungsten compound to tungsten oxide. Thus, the composite catalyst recovered from the drying chamber <NUM> of the spray dryer <NUM> may include the catalytically active compound deposited on the outer and pore surfaces of the catalyst support material, the zeolite particles, or both.

Referring again to <FIG>, the spray dryer <NUM> may include one or a plurality of catalyst outlets in the drying chamber <NUM>, each outlet fluidly coupled to a solid separator and blower <NUM> operable to pull air and spray dried composite catalyst out of the drying chamber <NUM>. A first composite catalyst stream <NUM> may be removed from a first outlet disposed at a converging end of the conical portion <NUM> of the drying chamber <NUM>. The converting end of the conical portion <NUM> may be disposed at a bottom end of the drying chamber <NUM> so that the first outlet is at the bottom of the drying chamber <NUM>. Composite catalyst spray dried in the drying chamber <NUM> may eventually descend to the conical portion <NUM> of the drying chamber <NUM>. The first composite catalyst stream <NUM> may be passed out of the drying chamber <NUM> and to a first solid separator <NUM>. The first solid separator <NUM> may be fluidly coupled to the blower <NUM>, which may be operable to pull the first composite catalyst stream <NUM> comprising composite catalyst and heated air out of the drying chamber <NUM> from the first catalyst outlet and transfer the first composite catalyst stream <NUM> to the first solid separator <NUM>. The first solid separator <NUM> may be operable to separate a first composite catalyst <NUM> from the heated air in the first composite catalyst stream <NUM>. The first solid separator <NUM> may be a cyclonic separator, filter, or other solid-gas separation device. The first composite catalyst <NUM> may be recovered from the first solid separator <NUM>. The heated gas may be drawn through the first solid separator by the blower <NUM> and removed from the process.

A second composite catalyst stream <NUM> may be removed from a second outlet of the drying chamber <NUM>. The second outlet may be disposed upstream of the first outlet relative to the flow of the composite catalyst downward through the drying chamber <NUM>. The second outlet may be disposed in the cylindrical section <NUM> of the drying chamber <NUM> or proximate a diverging end of the conical portion <NUM> of the drying chamber <NUM>. As the droplets of the catalyst precursor mixture <NUM> transition to solid composite catalyst particles in the drying chamber <NUM>, the heavier solid composite catalyst particles may descend more rapidly downward in the -Z direction of the coordinate axis in <FIG> compared to the lighter solid composite catalyst particles. As used throughout this disclosure, "heavier" composite catalyst particles may refer to composite catalyst particles that have greater density or greater average particle size compared to "lighter" composite catalyst particles. Thus, during steady state operation of the spray dryer <NUM>, a gradient in particle density, average particle size, or both, may form in drying chamber <NUM> in the vertical direction (+/-Z direction of the coordinate axis in <FIG>). Removing the composite catalyst from different vertical positions of the drying chamber <NUM> may enable recovery of composite catalysts with different average particles sizes, different densities, or both. Generally, removing the composite catalyst particles from a higher position (in a greater +Z position) within the drying chamber <NUM> may produce a composite catalyst stream that includes composite catalyst having a lesser density, average particle size, or both, compared to the first composite catalyst <NUM> recovered from the bottom of the drying chamber <NUM>.

The second composite catalyst stream <NUM> may be passed out of the drying chamber <NUM> and to a second solid separator <NUM>. The second solid separator <NUM> may be fluidly coupled to the blower <NUM>, which may be operable to pull the second composite catalyst stream <NUM> comprising composite catalyst and heated air out of the drying chamber <NUM> from the second catalyst outlet and transfer the second composite catalyst stream <NUM> to the second solid separator <NUM>. The second solid separator <NUM> may be operable to separate a second composite catalyst <NUM> from the heated gas in the second composite catalyst stream <NUM>. The second solid separator <NUM> may be a cyclonic separator, filter, or other solid-gas separation device. The second composite catalyst <NUM> may be recovered from the second solid separator <NUM>. The heated gas may be drawn through the second solid separator <NUM> by the blower <NUM> and removed from the process. The second composite catalyst <NUM> may have a lesser density, smaller average particle size, or both, compared to the first composite catalyst <NUM> recovered from the bottom of the drying chamber <NUM>. Although a first composite catalyst <NUM> and a second composite catalyst <NUM> are described, it is understood that one or a plurality of composite catalyst streams may be removed from the drying chamber at various positions to produce a plurality of composite catalysts, each having a different average particle size, average density, or both.

Following spray drying of the composite catalyst, the composite catalyst, such as the first composite catalyst, the second composite catalyst, or both, may be calcined in a calcination furnace. The calcination process may be a two-step calcination process. This two-step calcination process may ensure the decomposition of the triblock copolymer surfactant, such as the Pluronic® P <NUM> surfactant, and also the formation of stable and active catalytically active compound from the catalytically active compound precursor. For example, calcination may ensure formation of stable and active tungsten oxide species from the tungsten precursor, such as ammonium metatungstate. Calcination may be carried out in the presence of one or more of the following gases: air, oxygen, hydrogen, and nitrogen. Calcination may be carried out at calcination temperatures of from <NUM> to <NUM>. The thermal treatment conditions, including the type of gaseous environment and calcination temperature, may influence the tungsten oxide species that are formed. The type of tungsten oxide species formed influences the stability and metathesis activity of the catalyst composition, including the propylene yield. The two-step calcination process described here may produce stable tungsten oxide phases for self- and cross-metathesis. The first step of the calcination process follows the thermal decomposition of ammonium metatungstate as it is converted to tungsten oxide. In an embodiment, this first step is carried out at about <NUM> to <NUM> in the presence of air. There is a significant weight loss of the tungsten precursor. The degradation of the tungsten precursor and conversion of the tungsten precursor to tungsten oxide continues until the second step which is carried out at a calcination temperature of from <NUM> to <NUM>, at which the weight loss of the tungsten precursor is stabilized and active tungsten oxide species for metathesis are formed. In one or more embodiments, the composite catalyst may be first subjected to calcination at <NUM> for <NUM> hours and at <NUM> for <NUM> hours, with a ramping rate of <NUM> per minute until the first temperature is reached and <NUM> per minute until the second temperature is reached. Although the calcination process has been described with respect to composite catalysts having tungsten oxide as the catalytically active compound, it is understood that the calcination process may be used to complete formation of composite catalysts having other catalytically active compounds.

Evaluation of the physical characteristics of the spray-dried composite catalyst revealed a uniform dispersion of the catalytically active material, such as tungsten oxide, on the outer and pore surfaces of the catalyst support material. This uniform dispersion of catalytically active material may translate to greater conversions and greater propylene and ethylene yields for the composite catalyst compared to conventional metathesis catalysts prepared by conventional techniques, such as wet impregnation or incipient wetness impregnation.

The composite catalysts prepared by spray drying according to the present disclosure may have a reduced average particle size compared to the average particle size of metathesis catalyst prepared by conventional techniques, such as wet impregnation or incipient wetness impregnation. The composite catalysts may have an average particle size of less than or equal to <NUM> micrometers (µm), less than or equal to <NUM>, less than or equal to <NUM>, or even less than or equal to <NUM>. The composite catalysts of the present disclosure may have an average particle size of from <NUM> to <NUM>, from <NUM> to <NUM>, from <NUM> to <NUM>, from <NUM> to <NUM>, from <NUM> to <NUM>, from <NUM> to <NUM>, from <NUM> to <NUM>, from <NUM> to <NUM>, from <NUM> to <NUM>, from <NUM> to <NUM>, from <NUM> to <NUM>, or from <NUM> to <NUM>. The average particle size may be determined through scanning electron microscopy (SEM) or other known analytical methods.

The composite catalyst comprising the zeolite particles embedded within the catalyst support material and the catalytically active compound deposited on the outer and pore surfaces of the catalyst support material, the zeolite particles, or both, may be employed in a metathesis reaction process to convert butene to propene, ethene, and other olefins. The metathesis reaction process may include a metathesis reaction in combination with isomerization of butene, cracking, or both. As shown in Reaction <NUM> (RXN <NUM>), the isomerization of <NUM>-butene to <NUM>-butene, and the isomerization of <NUM>-butene to <NUM>-butene, is an equilibrium reaction, as denoted by the bi-directional arrows with single heads. The isomerization of <NUM>-butene and <NUM>-butene may be achieved with an isomerization catalyst. As used in the present disclosure, the term "isomerization catalyst" may refer to a catalyst that promotes isomerization of alkenes, including, for example, isomerization of <NUM>-butenes to <NUM>-butene. As shown in Reaction <NUM> (RXN <NUM>), the cross-metathesis of <NUM>-butene and <NUM>-butene may produce <NUM>-propene and <NUM>-pentene. As used in the present disclosure, the term "cross-metathesis" may refer to an organic reaction that involves the redistribution of fragments of alkenes by the scission and regeneration of carbon-carbon double bonds. In the case of cross-metathesis between <NUM>-butene and <NUM>-butene, the redistribution of these carbon-carbon double bonds through metathesis produces propene and C<NUM>-C<NUM> olefins. The cross-metathesis of <NUM>-butene and <NUM>-butene may be achieved with a metathesis catalyst, such as tungsten oxide. As used in the present disclosure, the term "metathesis catalyst" may refer to a catalyst that promotes the metathesis reaction of alkenes to form other alkenes. The metathesis catalyst may also isomerize <NUM>-butenes to <NUM>-butene through a "self-metathesis" reaction mechanism. <CHM>
<CHM>.

Referring to RXN <NUM> and RXN <NUM>, the isomerization and metathesis reactions are not limited to these reactants and products; however, RXN <NUM> and RXN <NUM> provide a simplified illustration of the reaction methodology. As shown in RXN <NUM>, metathesis reactions may take place between two alkenes. The groups bonded to the carbon atoms of the carbon-carbon double bond may be exchanged between the molecules to produce two new alkenes with the exchanged groups. The specific metathesis catalyst that is selected may generally determine whether a cis-isomer or trans-isomer is formed, as the formation of a cis-isomer or a trans-isomer may be, at least partially, a function of the coordination of the alkenes with the catalyst. <NUM>-butene may also self-metathesize in the presence of a metathesis catalyst to produce ethylene and <NUM> hexene through similar reaction mechanisms.

Further, as shown in the following Reaction <NUM> (RXN <NUM>), which is provided subsequently in this disclosure, "cracking" may refer to the catalytic conversion of C4+ alkenes to propene and other alkanes, alkenes, or alkanes and alkenes, for example, C<NUM>-C<NUM> alkenes. Cracking reactions are not limited to the reactants and products shown in RXN3; however, RXN <NUM> provide a simplified illustration of the cracking reaction.

Butene may be converted to propene and other olefins through metathesis and cracking by contacting a butene-containing feedstock with the composite catalyst of the present disclosure at reactions conditions sufficient to conduct the metathesis reaction. In one or more embodiments, the composite catalyst may include ZSM-<NUM> zeolite particles embedded in the catalyst support material comprising mesoporous silica. The composite catalyst may further include tungsten oxide as the catalytically active compound dispersed across the outer and pore surfaces of the mesoporous silica catalyst support, the ZSM-<NUM> zeolite particles, or both. The metathesis process may optionally include an additional isomerization catalyst to maintain an equilibrium concentration of <NUM>-butene and <NUM>-butene in the reactor. The isomerization catalyst may be a separate particulate catalyst disposed upstream of the composite catalyst or mixed with the composite catalyst.

Referring now to <FIG>, a reactor system <NUM> for conducting metathesis of butene is schematically depicted. The reactor system <NUM> may include a metathesis reactor <NUM> and a metathesis effluent separation system <NUM> downstream of the metathesis reactor <NUM>. The metathesis reactor <NUM> may be a fixed bed reactor or any other type of reactor suitable for conducting metathesis reactions. The metathesis reactor <NUM> may include a plurality of metathesis reactors in series or in parallel. The metathesis reactor <NUM> may be operable to contact a butene-containing feed <NUM> with the composite catalyst of the present disclosure in a metathesis reaction zone <NUM>. The metathesis reactor <NUM> may include inert packing material <NUM> upstream and downstream of the metathesis reaction zone <NUM> to secure the composite catalyst in the metathesis reaction zone <NUM>.

The butene-containing feed <NUM> may comprise <NUM>-butene, trans-<NUM>-butene, cis-<NUM>-butene, or combinations of these. The butene-containing feed <NUM> may further comprise other C<NUM>-C<NUM> components. The butene-containing feed <NUM> may comprise from <NUM> wt. % to <NUM> wt. % <NUM>-butene based on the total weight of the butene-containing feed <NUM>. For example, the butene-containing feed <NUM> may comprise from <NUM> wt. % to <NUM> wt. %, from <NUM> wt. % to <NUM> wt. %, from <NUM> wt. % to <NUM> wt. %, from <NUM> wt. % to <NUM> wt. %, from <NUM> wt. % to <NUM> wt. %, from <NUM> wt. % to <NUM> wt. %, from <NUM> wt. % to <NUM> wt. %, from <NUM> wt. % to <NUM> wt. %, from <NUM> wt. % to <NUM> wt. %, from <NUM> wt. % to <NUM> wt. %, from <NUM> wt. % to <NUM> wt. %, from <NUM> wt. % to <NUM> wt. %, from <NUM> wt. % to <NUM> wt. %, or from <NUM> wt. % to <NUM> wt. % <NUM>-butene based on the total weight of the butene-containing feed <NUM>. The butene-containing feed <NUM> may comprise from <NUM> wt. % to <NUM> wt. % <NUM>-butene (that is, cis-<NUM>-butene, trans-<NUM>-butene, or both) based on the total weight of the butene-containing feed <NUM>. For example, the feedstock <NUM> may comprise from <NUM> wt. % to <NUM> wt. %, from <NUM> wt. % to <NUM> wt. %, from <NUM> wt. % to <NUM> wt. %, from <NUM> wt. % to <NUM> wt. %, from <NUM> wt. % to <NUM> wt. %, from <NUM> wt. % to <NUM> wt. %, from <NUM> wt. % to <NUM> wt. %, from <NUM> wt. % to <NUM> wt. %, from <NUM> wt. % to <NUM> wt. %, from <NUM> wt. % to <NUM> wt. %, from <NUM> wt. % to <NUM> wt. %, from <NUM> wt. % to <NUM> wt. %, from <NUM> wt. % to <NUM> wt. %, or from <NUM> wt. % to <NUM> wt. % <NUM>-butene based on the total weight of the butene-containing feed <NUM>. Additionally, the butene-containing feed <NUM> may be substantially free of ethylene. For example, the butene-containing feed <NUM>, which may be substantially free of ethylene, may comprise less than <NUM> wt. % of ethylene based on the total weight of the butene-containing feed <NUM>.

In one or more embodiments, the butene-containing feed <NUM> may be a C4 Raffinate stream, such as but not limited to a Raffinate-<NUM> stream. Raffinate is the residue C4 stream from a naphtha cracking process or from a gas cracking process when one or more constituents are removed (the C4 stream typically containing, as its chief components, n-butane, <NUM>-butene, <NUM>-butene, isobutene, and <NUM>,<NUM>-butadiene, and optionally some isobutane and said chief components together forming up to <NUM>% or more of the C4 stream). The butene-containing feed <NUM> may include a raffinate-<NUM> stream. Raffinate-<NUM> is the C<NUM> residual obtained after separation of <NUM>,<NUM>-butadiene from the C<NUM> raffinate stream and comprises mainly <NUM>-butene, <NUM>-butene, and isobutene, which may make up from <NUM> wt. % to <NUM> wt. % of the raffinate-<NUM> stream. For example, the raffinate-<NUM> stream may comprise from <NUM> wt. % to <NUM> wt. % of <NUM>-butene, from <NUM> wt. % to <NUM> wt. % of <NUM>-butene, and from <NUM> wt. % to <NUM> wt. % isobutene, based on the total weight of the raffinate-<NUM> stream. The butene-containing feed <NUM> may comprise a raffinate-<NUM> stream. Raffinate-<NUM> is the C<NUM> residual obtained after separation of <NUM>,<NUM>-butadiene and isobutene from the C<NUM> raffinate stream and comprise mainly <NUM>-butene, <NUM>-butene, and n-butane, which may make up from <NUM> wt. % to <NUM> wt. % of the raffinate-<NUM> stream. For example, the raffinate-<NUM> stream may comprise from <NUM> wt. % to <NUM> wt. % of <NUM>-butene, from <NUM> wt. % to <NUM> wt. % of <NUM>-butene, and from <NUM> wt. % to <NUM> wt. % n-butane, based on the total weight of the raffinate-<NUM> stream. The butene-containing feed <NUM> may comprise a raffinate-<NUM> stream. Raffinate-<NUM> is the C<NUM> residual obtained after separation of <NUM>,<NUM>-butadiene, isobutene, and <NUM>-butene from the C<NUM> raffinate stream and comprises mainly <NUM>-butene, n-butane, and unseparated residual <NUM>-butene, which combined may make up from <NUM> wt. % to <NUM> wt. % of the raffinate-<NUM> stream. For example, the raffinate-<NUM> stream may comprise from <NUM> wt. % to <NUM> wt. % of <NUM>-butene and from <NUM> wt. % to <NUM> wt. % of n-butane, based on the total weight of the raffinate-<NUM> stream. The presence of isobutene, inert gases, and non-olefinic hydrocarbons, such as n-butane, in the butene-containing feed <NUM> may not negatively affect the target metathesis reactions, but may undergo cracking reactions through contact with the zeolite particles in the composite catalyst.

As depicted in <FIG>, a butene-containing feed <NUM> may be introduced into the metathesis reactor <NUM> and contacted with the composite catalyst in the metathesis reaction zone <NUM>, the composite catalyst may include the ZSM-<NUM> zeolite particles embedded in the mesoporous silica catalyst support material and tungsten oxide as the catalytically active compound dispersed across the outer and pore surfaces of the mesoporous silica catalyst support, the ZSM-<NUM> zeolite particles, or both. Contact of the butene-containing feed <NUM> with the composite catalyst may cause at least a portion of the butene in the butene-containing feed <NUM> to react to form propene and other olefins. The reactions may include cross-metathesis, cracking, or both.

The metathesis reaction zone <NUM> may be maintained at a metathesis reaction temperature sufficient to promote the cross-metathesis reaction of <NUM>-butene and <NUM>-butene. The metathesis reaction temperature may be from <NUM> degrees Celsius (°C) to <NUM>. For example, the metathesis reaction zone <NUM> may be maintained at a metathesis reaction temperature of from <NUM> to <NUM>, from <NUM> to <NUM>, from <NUM> to <NUM>, from <NUM> to <NUM>, from <NUM> to <NUM>, from <NUM> to <NUM>, from <NUM> to <NUM>, from <NUM> to <NUM>, from <NUM> to <NUM>, from <NUM> to <NUM>, from <NUM> to <NUM>, from <NUM> to <NUM>, from <NUM> to <NUM>, from <NUM> to <NUM>, from <NUM> to <NUM>, from <NUM> to <NUM>, from <NUM> to <NUM>, from <NUM> to <NUM>, from <NUM> to <NUM>, from <NUM> to <NUM>, from <NUM> to <NUM>, from <NUM> to <NUM>, from <NUM> to <NUM>, from <NUM> to <NUM>, from <NUM> to <NUM>, from <NUM> to <NUM>, or from <NUM> to <NUM>.

The composite catalysts prepared by the spray dry method of the present disclosure may exhibit enhanced metathesis performance compared to conventional metathesis catalysts prepared by conventional techniques, such as wet impregnation or incipient wetness impregnation as well as compared to dual catalyst systems comprising a combination of a metathesis catalyst and a cracking catalyst. The catalytic activity of the spray-dried composite catalyst of the present disclosure was evaluated for conversion of butene to propene in a fixed bed reactor and its performance was compared against a dual catalyst reaction system comprising a conventional metathesis catalyst prepared by wet impregnation and a separate zeolite cracking catalyst. The spray-dried composite catalyst was highly active and stable, and performed comparable to the dual-catalyst system with the conventional metathesis catalyst and the separate cracking catalyst. Thus, the composite catalysts of the present disclosure can provide comparable metathesis performance with a single catalyst that does not require preparation of a catalyst mixture or isolation and separation of two or more reaction zones within the metathesis reactor, which may result in unutilized dead zones within the reactor.

A metathesis effluent <NUM> comprising the propene and other olefins may be passed out of the metathesis reactor <NUM>. The metathesis effluent <NUM> may be passed to the metathesis effluent separation system <NUM> operable to separate the metathesis effluent <NUM> into a plurality of product streams, such as but not limited to, an ethylene stream <NUM>, a propene stream <NUM>, a C4 stream <NUM>, a C5+ stream <NUM>, or combinations of these. The ethylene stream <NUM>, propene stream <NUM>, or both may be passed to downstream processing units to purify the ethylene, propene, or both. The ethylene, propene, or both may be used as valuable intermediates in the production of polymers and other valuable chemical products. The C4 stream <NUM> may be recycled back to the metathesis reactor <NUM> or passed to one or more downstream processing operations. The C5+ stream <NUM> may be passed to one or more downstream processing operations for further processing.

The following examples illustrate one or more additional features of the present disclosure described previously. It should be understood that these examples are not intended to limit the scope of the disclosure or the appended claims in any manner.

In a typical synthesis, <NUM> grams of tetrapropyl ammonium bromide (TPABr) and <NUM> ammonium fluoride were dissolved in <NUM> grams of deionized water and stirred well for <NUM> minutes to produce a TPABr solution. <NUM> grams of fumed silica and <NUM> grams of aluminum nitrate were gradually added simultaneously to the TPABr solution while stirring vigorously. Once the solution gelled, the gel was mixed with a spatula for about <NUM> minutes until homogenized. The obtained gel was placed in a TEFLON®-lined acid digestive bomb and maintained at <NUM> for <NUM> days. After two days, the digestive bomb was removed from the oven and was quenched in cold water for <NUM> minutes. The contents of the digestive bomb were filtered and washed with <NUM> liter of deionized water. The molar composition of gel was <NUM> SiO<NUM>: <NUM> Al<NUM>O<NUM>: <NUM> (TPA)Br: <NUM> NH<NUM>F: <NUM><NUM>O. The solid products obtained were washed with water and dried at <NUM> overnight. The template was removed by calcination in air at <NUM> for <NUM> hours with a ramp up of <NUM> per minute.

The MFI-<NUM> cracking catalyst of Example <NUM> was analyzed using X-Ray Diffraction (XRD). Referring to <FIG>, the XRD plot for the MFI-<NUM> cracking catalyst of Example <NUM> shows the characteristic peaks for the MFI-<NUM> cracking catalyst at <NUM>-theta equal to <NUM> degrees (°), <NUM>°, <NUM>°, and <NUM>°.

In Comparative Example <NUM>, a comparative metathesis catalyst comprising tungsten oxide supported on a mesoporous silica support was prepared. The metathesis catalyst of Comparative Example <NUM> was prepared through a wet impregnation technique. About <NUM> grams of the silica support material and about <NUM> of ammonium metatungstate (<NUM>% trace metals basis) were added to a round bottom flask. The silica support material was CARiACT® Grade Q-<NUM> mesoporous silica obtained from Fuji Silysia Chemicals, Ltd and calcined at <NUM> for three hours and then at <NUM> for five hours, with a ramping rate of <NUM> per minute. About <NUM> of deionized water was then added to the flask. A magnetic stir bar was added to the flask and the flask is placed on a stir plate that was programmed to run at <NUM> rpm, for roughly two hours. The magnetic stir bar was removed from the flask, and the flask was connected to a rotary evaporator. The conditions for operations of the rotary evaporator were: rotation set to <NUM> rpm, temperature of the water bath set to <NUM>, vacuum set to <NUM> millibar, and the cooling liquid (<NUM>% water and <NUM>% glycol) was maintained at <NUM>. Following that, the catalytic composition was placed in a drying oven overnight at <NUM>. The dried catalyst was calcined at <NUM> for <NUM> hours and at <NUM> for <NUM> hours, with a ramping rate of <NUM> per minute until the first temperature is reached and <NUM> per minute until the second temperature is reached. Calcination of these samples was carried out in a VULCAN® <NUM>-<NUM> furnace (commercially available from Dentsply Ceramco, headquartered in York, Pa. The comparative metathesis catalyst of Comparative Example <NUM> included a tungsten oxide loading of <NUM> weight percent based on the total weight of the comparative metathesis catalyst.

The metathesis catalyst of Comparative Example <NUM> was analyzed using X-Ray Diffraction (XRD). The XRD data for the Examples of the present disclosure were collected using a D4 Endeavor X-Ray Diffractometer from Bruker AXS GmbH (Karlsruhe, Germany) and analyzed using DIFFRAC. <NUM> version (available from Bruker), which had a built-in PDF library to match the perfect scan. Analyses were carried out at room temperature in the <NUM>-theta range from <NUM> degrees to <NUM> degrees. As shown in <FIG>, the XRD plot for the metathesis catalyst of Comparative Example <NUM> includes the characteristic peaks for silica as well as characteristic peaks for tungsten oxide in the range of <NUM>-theta of between <NUM>° and <NUM>°.

Additionally, the metathesis catalyst of Comparative Example <NUM> was subjected to scanning electron microscopy (SEM) to determine the average particle size. The metathesis catalyst of Comparative Example <NUM> prepared by wet impregnation without spray drying had an average particle size of <NUM> micrometers (µm).

In Example <NUM>, a composite catalyst was prepared according to the methods of the present disclosure using the MFI-<NUM> cracking catalyst of Example <NUM>. A first solution was prepared by combining <NUM> grams of silica, <NUM> grams of MFI-<NUM> cracking catalyst from Example <NUM>, and <NUM> milliliters (mL) of water. The silica was CATiRAC™, grade Q-<NUM> silica from Fuji Silysia Chemicals, Ltd. The mixture of silica and MFI-<NUM> cracking catalyst in water was stirred for <NUM> minutes at a speed of greater than <NUM> rotations per minute (rpm). A second solution comprising <NUM> grams of surfactant, <NUM> of water, and <NUM> of ethanol was prepared and stirred for <NUM> minutes at greater than <NUM> rpm to fully dissolve the surfactant. The surfactant was PLURONIC® P123 poly(ethylene glycol)-block-poly(propylene glycol)-block-poly(ethylene glycol) surfactant obtained from Sigma Aldrich. A third solution was prepared by mixing <NUM> grams of tungsten precursor (ammonium meta tungstate hexahydrate) with <NUM> of water and shaking the third solution vigorously until all the tungsten precursor was dissolved. The third solution was then combined with the second solution and the resulting mixture was stirred for <NUM> minutes. The combined mixture of the second solution and third solution was then added to the first solution comprising the silica and MFI-<NUM> cracking catalyst to produce the spray dryer solution. The spray dryer solution was stirred at a speed of greater than <NUM> rpm for three days. The resulting spray dryer solution was milky and homogeneous in appearance.

The spray dryer solution was then spray dried using a GEA Niro spray dryer MOBILE MINOR™ for aqueous feeds. The drying chamber of the spray dryer had a cylinder size of <NUM> millimeters (mm), a height of <NUM>, and a cone angle of <NUM> degrees. Spray drying was conducted with a target feed flow rate of <NUM> milliliters per minute (mL/min) although the flow rate was constantly adjusted to maintain the exhaust temperature less than <NUM>. The surface temperature of the drying chamber was maintained at <NUM> and the fan speed of the fan withdrawing air and composite catalyst out of the drying chamber was set to <NUM> rpm.

To start the spray drying process, the spray dryer was turned on and allowed to gradually heat while feeding deionized water. Once the surface temperature of the drying chamber reached the target temperature of <NUM> and the temperature of the outlet air stabilized, the spray dryer solution was introduced to the spray dryer in place of the deionized water. The composite catalyst was removed from the spray dryer at two locations: the bottom of the cone portion of the drying chamber and a position at the side of the drying chamber just above the conical portion of the drying chamber. The composite catalyst withdrawn from the bottom of the drying chamber will be referred as composite catalyst 3A, and the composite catalyst withdrawn from the side of the drying chamber will be referred to as composite catalyst 3B. The composite catalyst 3B comprised catalyst particles that were lighter in density and slightly smaller in average particle size compared to the composite catalyst 3A.

The composite catalyst 3A and composite catalyst 3B were calcined according to the calcination process previously described in Example <NUM>. The composite catalyst 3A of Example <NUM> was analyzed using X-Ray Diffraction (XRD). Referring to <FIG>, the XRD plot for the composite catalyst 3A of Example <NUM> includes the characteristic peaks for the MFI-<NUM> cracking catalyst of Example <NUM> at <NUM> theta equal to <NUM> degrees (°), <NUM>°, <NUM>°, and <NUM>° as well as the characteristic peak for tungsten oxide at <NUM> theta equal to about <NUM>°.

Additionally, the composite catalyst 3A, composite catalyst 3B, and a <NUM>:<NUM> mixture by weight of composite catalysts 3A and 3B were was subjected to scanning electron microscopy (SEM) to determine the average particle size. The values for the average particle size for the composite catalysts of Example <NUM> and the metathesis catalyst of Comparative Example <NUM> are provided in Table <NUM>. As shown in Table <NUM>, the spray drying process in Example <NUM> produces composite catalysts having average particle sizes that are substantially less than the average particles sizes of conventional metathesis catalysts prepared through wet impregnation, such as those prepared in Comparative Example <NUM>.

In Example <NUM>, the composite catalyst 3B of Example <NUM> was used to conduct metathesis of a butene-containing feed. The metathesis reactions were conducted in fixed bed reactor at atmospheric pressure. The fixed bed reactor was a <NUM>-fold High Throughput reactor unit. A fixed amount of <NUM> grams of the composite catalyst 3B was packed into the reactor between two layers of silicon carbide. The silicon carbide was used as an inert packing material to maintain the catalyst in the reactor and did not participate in the metathesis reaction.

The composite catalyst 3B of Example <NUM> was first pretreated and activated at a temperature of <NUM> under nitrogen at a flow rate of <NUM> milliliters per minute (mL/min) for <NUM> hours. The temperature of the fixed bed reactor was adjusted to <NUM> at atmospheric pressure, and a butene-containing feed was introduced to the fixed bed reactor. The butene-containing feed included <NUM> wt. % isobutane, <NUM> wt. % n-butane, <NUM> wt. % trans-<NUM>-butene, <NUM> wt. % cis-<NUM>-butene, and <NUM> wt. % <NUM>-butene based on the total weight of the butene-containing feed. The butene-containing feed was passed through the fixed bed reactor at a weight hourly space velocity (WHSV) of <NUM> per hour (h-<NUM>) for <NUM> hours. Quantitative analysis of the reactor effluent was performed using a gas chromatograph (commercially available as Agilent GC-7890B) with a thermal conductivity detector (TCD) and two flame ionization detectors (FID).

Referring to <FIG>, the total conversion of butene and yields of each of ethene, propene, five-carbon hydrocarbons (C5), and hydrocarbons having <NUM> or more carbons (C6+) are provided as percentages. The conversion and yields in <FIG> are the average of <NUM> samples taken periodically over the <NUM> hour run time of the experiment. The composite catalyst 3B of Example <NUM> resulted in a total conversion of <NUM> %, a yield of propene of <NUM> %, and a yield of ethene of <NUM> %.

In Comparative Example <NUM>, a butene-containing feed was contacted with a dual catalyst system that included the metathesis catalyst of Comparative Example <NUM> and the MFI-<NUM> cracking catalyst of Example <NUM>. The metathesis catalyst of Comparative Example <NUM> (<NUM> grams) and the MFI-<NUM> catalyst of Example <NUM> (<NUM> grams) were packed into the fixed bed reactor with the metathesis catalyst disposed upstream of the MFI-<NUM> cracking catalyst. The metathesis catalyst of Comparative Example <NUM> was placed upstream of the MFI-<NUM> cracking catalyst of Example <NUM>.

The catalysts of the dual catalyst system of Comparative Example <NUM> were pretreated and activated according to the process described in Example <NUM>. Following pretreatment, the reactor temperature was adjusted to <NUM> at atmospheric pressure, and a butene-containing feed was introduced to the fixed bed reactor. The butene-containing feed was passed through the fixed bed reactor at a weight hourly space velocity (WHSV) of <NUM> per hour (h-<NUM>) for <NUM> hours. Quantitative analysis of the reactor effluent was performed using a gas chromatograph (commercially available as Agilent GC-7890B) with a thermal conductivity detector (TCD) and two flame ionization detectors (FID).

Referring to <FIG>, the total conversion of butene and yields of each of ethene, propene, five-carbon hydrocarbons (C5), and hydrocarbons having <NUM> or more carbons (C6+) are provided as percentages. The conversion and yields in <FIG> are the average of <NUM> samples taken periodically over the <NUM> hour run time of the experiment. The dual catalyst system of Comparative Example <NUM> resulted in a total conversion of <NUM> %, a yield of propene of <NUM> %, and a yield of ethene of <NUM> %.

As shown in <FIG>, the composite catalyst of Example <NUM> (<FIG>) produced results comparable to the dual catalyst system of Example <NUM> having the metathesis catalyst of Comparative Example <NUM> and the zeolite of Example <NUM> (<FIG>). In fact, the composite catalyst of Example <NUM> exhibited a greater overall conversion of butene, which demonstrates overall greater catalytic activity compared to the metathesis catalyst of Comparative Example <NUM>. Not intending to be bound by any particular theory, it is believe that the process for making the composite catalyst of Example <NUM> according to the present disclosure reduces the average particle size and increases both the surface area and degree of dispersion of the catalytically active compound over the surfaces of the composite catalyst compared to the metathesis catalyst of Comparative Example <NUM>, which was prepared by wet impregnation. This lesser average particle size, greater surface area, and greater dispersion of catalytically active compound on the surfaces are believed to result in greater catalytic activity of the composite catalysts prepared by the methods of the present disclosure compared to metathesis catalysts made using conventional wet impregnation or incipient wetness impregnation synthesis methods.

In Example <NUM>, the influence of the average particle size of the composite catalyst of Example <NUM> on the metathesis of butene was investigated by conducting the metathesis reaction according to the process in Example <NUM> with the composite catalyst 3A, composite catalyst 3B, and a composite catalyst mixture that included both 3A and 3B. As previously discussed, the average particle size of the composite catalyst 3A was greater than the average particle size of the composite catalyst 3B. The butene metathesis reactions were conducted in accordance with the process described in Example <NUM> at temperatures of <NUM>, <NUM>, and <NUM> for each of the composite catalysts and the composite catalyst mixture. The compositie catalyst mixture included equal amounts by weight of composite catalyst 3A and composite catalyst 3B. The average yields for propene, ethene, C5 hydrocarbons, and C6+ hydrocarbons resulting for each of the butene metathesis reactions of Example <NUM> are provided below in Table <NUM>.

As shown by the results in Table <NUM>, the composite catalyst 3B having the smaller average particle size produced better selectivity towards propene at greater metathesis temperatures compared to the composite catalyst 3A having the greater average particle size. At lower temperatures, the composite catalyst 3A provided better metathesis performance with respect to propene selectivity.

Determination of "Conversion" was calculated according to formula <NUM>.

Similarly, determination of "Conversion-C<NUM>" was calculated according to formula <NUM>.

Claim 1:
A method of preparing a composite catalyst, the method comprising:
combining a catalyst support material, zeolite particles, a triblock copolymer surfactant, a catalytically active compound precursor, and a diluent to produce a catalyst precursor composition;
mixing the catalyst precursor composition to produce a catalyst precursor mixture in which the catalyst support material and the zeolite particles are suspended in the diluent;
spray drying the catalyst precursor mixture, where spray drying comprises:
atomizing the catalyst precursor mixture to produce a plurality of droplets; and
drying the plurality of droplets in a drying chamber, where drying removes the diluent from each of the plurality of droplets to form agglomerates comprising the zeolite particles at least partially secured within the catalyst support material and causes the catalytically active compound precursor to react to form a catalytically active compound deposited on outer surfaces and pore surfaces of the catalyst support material, the zeolite particles, or both;
removing a first composite catalyst from the drying chamber at a first outlet disposed at a bottom of the drying chamber; and
removing a second composite catalyst from the drying chamber at a second outlet upstream of the first outlet, where the second composite catalyst has an average particle size or a density less than an average particle size or a density, respectively, of the first composite catalyst.