Patent Application
20240417268
The present disclosure generally relates to chemical processing and, more specifically, to zeolite catalyst compositions, methods of making the zeolite catalyst compositions, and methods of cracking hydrocarbons using the zeolite catalyst compositions.
The worldwide increasing demand for olefins remains a major challenge for many integrated refineries. In particular, the production of some valuable olefins, such as ethylene and propylene, has attracted increased attention as pure olefin streams are considered the building blocks for polymer synthesis. The production of olefins depends on several process variables, such as the feed type, operating conditions, and the type of catalyst used. Many cracking catalysts utilize a zeolite as a support material. However, these cracking catalysts can have limitations with respect to stability and heavy oil conversion. For example, conventional catalysts may have poor polyaromatic cracking conversion. Accordingly, new zeolites and zeolite-based catalysts with various improved attributes are needed.
There is a need for methods of making zeolite compositions for cracking hydrocarbons. Conventional zeolite compositions can be formed by processes that utilize calcining kaolinite to form metakaolin, prior to making the zeolite composition. Presently discovered, and included in the embodiments described in the present disclosure, are methods in which zeolite compositions are produced by calcining a clay mineral composition having greater than or equal to 10 weight percent halloysite to form metakaolin prior to making the zeolite composition. Such embodiments may yield zeolite compositions that demonstrate improved efficiency in hydrocarbon cracking.
According to one or more embodiments, methods of forming a ZSM-5 zeolite may comprise calcining one or more clay mineral compositions to form metakaolin, where the one or more clay mineral compositions may comprise greater than or equal to 10 wt. % halloysite. The methods may further comprise forming a slurry by combining at least the metakaolin, ZSM-5 zeolite seeds, a basic compound, and a silica source; hydrothermally treating the slurry to form a hydrothermal product; and calcining the hydrothermal product to form the ZSM-5 zeolite.
This summary is provided to introduce a selection of concepts that are further described in the detailed description. This summary is not intended to identify key or essential features of the claimed subject matter, nor is it intended to be used as an aid in limiting the scope of the claimed subject matter.
Additional features and advantages of the described embodiments will be set forth in the detailed description that follows. The additional features and advantages of the described embodiments will be, in part, readily apparent to those skilled in the art from that description or recognized by practicing the described embodiments, including the detailed description that follows as well as the drawings and the claims.
The following detailed description of specific embodiments of the present disclosure can be best understood when read in conjunction with the following drawings, where like structure is indicated with like reference numerals and in which:
When describing the simplified schematic illustration of
Additionally, the arrows in the simplified schematic illustration of
The arrows in the simplified schematic illustration of
Reference will now be made in greater detail to various embodiments, some embodiments of which are illustrated in the accompanying drawings.
The present disclosure is directed to methods of forming a ZSM-5 zeolite and processes for cracking hydrocarbon feeds using the resulting ZSM-5 zeolite. In particular, the present disclosure is directed to methods of forming a ZSM-5 zeolite that may include calcining a clay mineral composition to form metakaolin. The clay mineral composition may include greater than or equal to 10 weight percent halloysite. The method may further include forming a slurry by combining the metakaolin formed from calcining the kaolin clay, ZSM-5 zeolite seeds, a basic compound, and a silica source. The method of forming the ZSM-5 zeolite may further include hydrothermally treating the slurry to form a hydrothermal product, and calcining the hydrothermal product to form the ZSM-5 zeolite. A process of the present disclosure for cracking a hydrocarbon feed using the resulting ZSM-5 zeolite may include contacting the hydrocarbon feed with steam in the presence of a cracking catalyst in a reactor under reaction conditions sufficient to cause at least a portion of the hydrocarbon feed to undergo one or more cracking reactions to produce a cracking effluent comprising light olefins, light aromatic compounds, or both. The cracking catalyst may comprise the ZSM-5 zeolite formed from a clay mineral composition comprising greater than or equal to 10 weight percent halloysite.
As used throughout the present disclosure, the term “light olefins” refers to olefin compounds having from 2 to 4 carbon atoms.
As used throughout the present disclosure, the term “light aromatic compounds” refers to compounds having an aromatic ring structure from 6 to 11 carbon atoms, such as benzene, toluene, xylene, or ethylbenzene.
As used throughout the present disclosure, “cracking” generally refers to a chemical reaction where carbon-carbon bonds are broken. For example, a molecule having carbon to carbon bonds is broken into more than one molecule by the breaking of one or more of the carbon to carbon bonds, or is converted from a compound which includes a cyclic moiety, such as a cycloalkane, cycloalkane, naphthalene, an aromatic or the like, to a compound which does not include a cyclic moiety or contains fewer cyclic moieties than prior to cracking.
It should be understood that a “product effluent” generally refers to a stream that exits a system component such as a reactor or reactor zone, following a particular reaction, and generally has a different composition (at least proportionally) than the stream that entered the reactor or reaction zone, such as the hydrocarbon feed.
As used throughout the present disclosure, a “reactor” refers to a vessel in which one or more chemical reactions may occur between one or more reactants optionally in the presence of one or more catalysts.
As used throughout the present disclosure, a “reaction zone” refers to an area where a particular reaction takes place in a reactor.
As used throughout the present disclosure, the term “residence time” refers to the amount of time that reactants are in contact with a catalyst, at reaction conditions, such as at the reaction temperature.
Referring now to
As described herein, at block 102, the method may include calcining one or more clay mineral compositions to form metakaolin. Calcining may comprise heating a material to an elevated temperature, and holding the temperature of the material at an elevated temperature for a duration of time in an environment comprising oxygen. A clay mineral composition may comprise one or more clay minerals, such as kaolinite and halloysite. In embodiments, two or more clay mineral compositions may be used. That is, in embodiments, at least two separate clay mineral compositions comprising a different weight percentage of clay minerals may be used as described herein. When a weight percentage of a specific clay mineral, such as halloysite, is provided for the “one or more clay mineral compositions”, the weight percentage refers to the weight of the specific clay mineral in relation to the summation of the one or more clay mineral compositions, unless specified otherwise.
In embodiments, the one or more clay mineral compositions may comprise kaolin. As used herein, “kaolin” or “kaolin clay” refers to a class of clay minerals comprising the chemical formula Al2Si2O5(OH)4, which may include the clay minerals kaolinite, halloysite, dickite, and nacrite. In embodiments, the one or more clay mineral compositions may comprise halloysite, kaolinite, dickite, nacrite or combinations thereof. Kaolinite has the chemical formula Al2Si2O5(OH)4, and may occur in platy forms. Halloysite has a similar composition to kaolinite except that halloysite may naturally occur as small cylinders and may have additional water molecules. In its fully hydrated form, halloysite has additional water molecules between layers of the crystal structure and has a chemical formula of Al2Si2Os (OH)4·2H2O. Halloysite may also be partially dehydrated, meaning that at least a portion of the water molecules have been removed from the halloysite structure. As used herein, the term “halloysite” is used to refer to both the fully hydrated and partially hydrated forms of halloysite, unless specified otherwise.
In embodiments, the one or more clay mineral compositions may comprise greater than or equal to 10 weight percent (wt. %) halloysite, such as greater than or equal to 15 wt. %, greater than or equal to 20 wt. %, greater than or equal to 25 wt. %, greater than or equal to 30 wt. %, greater than or equal to 35 wt. %, greater than or equal to 40 wt. %, greater than or equal to 45 wt. %, greater than or equal to 50 wt. %, greater than or equal to 55 wt. %, greater than or equal to 60 wt. %, greater than or equal to 65 wt. %, greater than or equal to 70 wt. %, greater than or equal to 75 wt. %, greater than or equal to 80 wt. %, greater than or equal to 85 wt. %, greater than or equal to 90 wt. %, greater than or equal to 95 wt. %, greater than or equal to 99 wt. %, or even greater than or equal to 99.99 wt. % halloysite, based on the total weight of the one or more clay mineral compositions. In embodiments, the one or more clay mineral compositions may comprise of from 10 wt. % to 100 wt. % halloysite, such as from 20 wt. % to 100 wt. %, from 30 wt. % to 100 wt. %, from 40 wt. % to 100 wt. %, from 50 wt. % to 100 wt. %, from 60 wt. % to 100 wt. %, from 70 wt. % to 100 wt. %, from 80 wt. % to 100 wt. %, from 90 wt. % to 100 wt. %, from 10 wt. % to 90 wt. %, from 20 wt. % to 90 wt. %, from 30 wt. % to 90 wt. %, from 40 wt. % to 90 wt. %, from 50 wt. % to 90 wt. %, from 60 wt. % to 90 wt. %, from 70 wt. % to 90 wt. %, from 80 wt. % to 90 wt. %, from 10 wt. % to 80 wt. %, from 20 wt. % to 80 wt. %, from 30 wt. % to 80 wt. %, from 40 wt. % to 80 wt. %, from 50 wt. % to 80 wt. %, from 60 wt. % to 80 wt. %, from 70 wt. % to 80 wt. %, from 10 wt. % to 70 wt. %, from 20 wt. % to 70 wt. %, from 30 wt. % to 70 wt. %, from 40 wt. % to 70 wt. %, from 50 wt. % to 70 wt. %, from 60 wt. % to 70 wt. %, from 10 wt. % to 60 wt. %, from 20 wt. % to 60 wt. %, from 30 wt. % to 60 wt. %, from 40 wt. % to 60 wt. %, from 50 wt. % to 60 wt. %, from 10 wt. % to 50 wt. %, from 20 wt. % to 50 wt. %, from 30 wt. % to 50 wt. %, from 40 wt. % to 50 wt. %, from 10 wt. % to 40 wt. %, from 20 wt. % to 40 wt. %, from 30 wt. % to 40 wt. %, from 10 wt. % to 30 wt. %, from 20 wt. % to 30 wt. %, or from 10 wt. % to 20 wt. % halloysite, based on the total weight of the one or more clay mineral compositions.
In embodiments, the one or more clay mineral compositions may comprise less than or equal to 90 weight percent (wt. %) kaolinite, such as less than or equal 50 wt. %, less than or equal to 20 wt. %, less than or equal to 10 wt. %, less than or equal to 5 wt. %, less than or equal to 2 wt. %, less than or equal to 1 wt. %, less than or equal to 0.5 wt. %, or even less than or equal to 0.1 wt. % kaolinite, based on the total weight of the one or more clay mineral compositions. In embodiments, the one or more clay mineral compositions may comprise of from 0 wt. % to 90 wt. % kaolinite, such as from 0 wt. % to 80 wt. %, from 0 wt. % to 70 wt. %, from 0 wt. % to 60 wt. %, from 0 wt. % to 50 wt. %, from 0 wt. % to 40 wt. %, from 0 wt. % to 30 wt. %, from 0 wt. % to 20 wt. %, from 0 wt. % to 10 wt. %, from 0 wt. % to 5 wt. %, from 0 wt. % to 2 wt. %, from 0 wt. % to 1 wt. %, or from 0 wt. % to 0.5 wt. % kaolinite, based on the total weight of the one or more clay mineral compositions.
Without intending to be bound by any particular theory, it is believed that using one or more clay mineral compositions having a greater amount of halloysite, such as greater than or equal to 10 wt. % halloysite, in the methods described in the present disclosure may provide a ZSM-5 zeolite having improved properties, such as but not limited to increased surface area compared to methods using one or more clay minerals having less than 10 wt. % halloysite.
In embodiments, the one or more clay minerals may be naturally occurring. As used herein, “naturally occurring” refers to clay minerals that are not synthesized. In embodiments, the naturally occurring clay minerals may be processed. For instance, the clay minerals may be processed to remove impurities. Without intending to be bound by any particular theory, it is believed that the use of clay minerals that are naturally occurring may improve the environmental footprint of the methods disclosed in the present disclosure compared to using clay minerals that are synthesized.
In embodiments, calcining the clay minerals may comprise heating the clay minerals at a temperature of greater than or equal to 550° C., such as greater than or equal to 600° C., or greater than or equal to 650° C. In embodiments, calcining the one or more clay minerals may comprise heating the one or more clay minerals at a temperature of from 550° C. to 900° C., such as from 550° C. to 800° C., from 550° C. to 750° C., from 600° C. to 900° C., from 600° C. to 800° C., from 600° C. to 750° C., from 650° C. to 900° C., from 650° C. to 800° C., or from 650° C. to 750° C. In embodiments, calcining the one or more clay minerals may comprise heating the one or more clay minerals for a duration of greater than or equal to 10 minutes (min), such as greater than or equal to 30 min, greater than or equal to 60 min, or greater than or equal to 90 min. In embodiments, calcining the one or more clay minerals may comprise heating the one or more clay minerals for a duration of from 10 min to 2 days.
In embodiments, through calcination, at least a portion of the clay mineral compositions may be converted to metakaolin. As used herein, “metakaolin” refers to a compound comprising chemical formula Al2Si2O7. Metakaolin may be formed by heating kaolin, such as one or more clay mineral compositions comprising kaolinite, halloysite, or combinations thereof to an elevated temperature for a duration of time. In embodiments, changes in properties of the one or more clay mineral compositions may result in changes in properties of the metakaolin derived from calcining the clay mineral compositions. That is, the clay mineral compositions comprising an increased amount of halloysite, such as greater than or equal to 10 wt. % halloysite, may be converted to metakaolin having at least one or more different properties, such as different average surface area or different average pore volume, compared to metakaolin derived from one or more clay mineral compositions having less than 10 wt. % halloysite.
Surface area, pore volume, average pore size, and pore size distribution may be measured by nitrogen (N2) adsorption isotherms performed at 77 Kelvin (K) (such as with a Micrometrics ASAP 2020 system). As would be understood by those skilled in the art, Brunauer, Emmett, and Teller (BET) analysis methods may be utilized to calculate the surface area from the N2 adsorption isotherms, and the Barrett, Joyner and Halenda (BJH) calculation may be used to determine pore volume and pore size distribution from the N2 adsorption isotherms.
In embodiments, the metakaolin produced from calcining the clay mineral compositions may have a surface area of greater than or equal to 30 m2/g, such as greater than or equal to 35 m2/g, greater than or equal to 40 m2/g, greater than or equal to 45 m2/g, greater than or equal to 50 m2/g, greater than or equal to 55 m2/g, or even greater than or equal to 60 m2/g. In embodiments, the metakaolin may have a surface area of from 10 m2/g to 100 m2/g. For instance, in embodiments, the metakaolin may have a surface area of from 20 m2/g to 100 m2/g, from 30 m2/g to 100 m2/g, from 40 m2/g to 100 m2/g, from 50 m2/g to 100 m2/g, from 60 m2/g to 100 m2/g, from 10 m2/g to 80 m2/g, from 20 m2/g to 80 m2/g, from 30 m2/g to 80 m2/g, from 40 m2/g to 80 m2/g, from 50 m2/g to 80 m2/g, or from 60 m2/g to 80 m2/g. The surface area is determined using BET analysis.
In embodiments, the metakaolin produced from calcining the clay mineral compositions may have an average pore volume of greater than or equal to 0.15 cm3/g, such as greater than or equal to 0.20 cm3/g, greater than or equal to 0.25 cm3/g, or greater than or equal to 0.30 cm3/g. In embodiments, the metakaolin may have an average pore volume of from 0.1 cm3/g to 0.5 cm3/g. For instance, in embodiments, the metakaolin may have an average pore volume of from 0.2 cm3/g to 0.5 cm3/g, or from 0.3 cm3/g to 0.5 cm3/g. In embodiments, the metakaolin may have an average pore diameter of from 0.5 nm to 50 nm. The average pore volume and the average pore diameter are determined using BJH analysis.
Referring again to
The ZSM-5 zeolite seeds may be active to catalytically crack hydrocarbon compounds. As used in the present disclosure, “ZSM-5” or “ZSM-5 zeolites” refers to zeolites having an MFI framework type according to the IUPAC zeolite nomenclature and consisting of silica and alumina. ZSM-5 refers to “Zeolite Socony Mobil-5” and is a pentasil family zeolite that can be represented by the chemical formula NanAlnSi96-nO192·16H2O, where 0<n<27. “ZSM-5 zeolite seeds” refers to preformed ZSM-5 zeolites that are present in the slurry of the present disclosure, which may direct the formation of the ZSM-5 zeolite in the methods described in the present disclosure.
In embodiments, the ZSM-5 zeolite seeds may have a silica to alumina weight ratio (SAR) of from 10 to 280, such as from 10 to 200, from 10 to 150, from 10 to 100, from 50 to 280, from 50 to 200, from 50 to 150, or from 50 to 100.
In embodiments, the ZSM-5 zeolite seeds may have a surface area of greater than or equal to 200 m2/g, such as greater than or equal to 250 m2/g, greater than or equal to 300 m2/g, or greater than or equal to 350 m2/g. In embodiments. The ZSM-5 zeolite seeds may have a surface area of from 200 m2/g to 500 m2/g, from 200 m2/g to 400 m2/g, from 200 m2/g to 375 m2/g, from 250 m2/g to 500 m2/g, from 250 m2/g to 400 m2/g, from 250 m2/g to 375 m2/g, from 300 m2/g to 500 m2/g, from 300 m2/g to 400 m2/g, from 300 m2/g to 375 m2/g, from 350 m2/g to 500 m2/g, from 350 m2/g to 400 m2/g, or from 350 m2/g to 375 m2/g. The surface area is determined using BET analysis.
In embodiments, the ZSM-5 zeolite seeds may have an average total pore volume of greater than or equal to 0.10 cm3/g, such as greater than or equal to 0.15 cm3/g, or greater than or equal to 0.20 cm3/g. In embodiments, the ZSM-5 zeolite seeds may have an average total pore volume of less than 0.35 cm3/g, less than 0.30 cm3/g, or less than 0.25 cm3/g. In embodiments, the ZSM-5 zeolite seeds may have an average total pore volume of from 0.1 cm3/g to 0.5 cm3/g. For instance, in embodiments, the ZSM-5 zeolite seeds may have an average total pore volume of from 0.1 cm3/g to 0.4 cm3/g, from 0.1 cm3/g to 0.3 cm3/g from 0.1 cm3/g to 0.25 cm3/g, from 0.15 cm3/g to 0.4 cm3/g, from 0.15 cm3/g to 0.3 cm3/g, from 0.15 cm3/g to 0.25 cm3/g, from 0.2 cm3/g to 0.4 cm3/g, from 0.2 cm3/g to 0.3 cm3/g, or from 0.2 cm3/g to 0.25 cm3/g. The average total pore volume is determined using BJH analysis.
In embodiments, the basic compound may be any basic compound. In embodiments, the basic compound may comprise sodium hydroxide. In embodiments, the basic compound may comprise sodium carbonate. Without intending to be bound by any particular theory, it is believed that the basic compound may facilitate dissolution of the silica source in the slurry.
In embodiments, the silica source may be any source comprising silica. In embodiments, the silica source may comprise colloidal silica.
In embodiments, the slurry may comprise of from 0.5 wt. % to 5 wt. % of the metakaolin, based on the total weight of the slurry. For instance, the slurry may comprise of from 0.5 wt. % to 5 wt. %, from 0.5 wt. % to 4 wt. %, from 0.5 wt. % to 3 wt. %, from 0.5 wt. % to 2 wt. %, from 0.5 wt. % to 1 wt. %, from 1 wt. % to 5 wt. %, from 1 wt. % to 4 wt. %, from 1 wt. % to 3 wt. %, from 1 wt. % to 2 wt. %, from 2 wt. % to 5 wt. %, from 2 wt. % to 4 wt. %, from 2 wt. % to 3 wt. %, from 3 wt. % to 5 wt. %, from 3 wt. % to 4 wt. %, or from 4 wt. % to 5 wt. % of the metakaolin, based on the total weight of the slurry.
In embodiments, the slurry may comprise of from 0.01 wt. % to 5 wt. % of the ZSM-5 zeolite seeds, based on the total weight of the slurry. For instance, the slurry may comprise from 0.01 wt. % to 5 wt. %, from 0.01 wt. % to 4 wt. %, from 0.01 wt. % to 3 wt. %, from 0.01 wt. % to 2 wt. %, from 0.01 wt. % to 1 wt. %, from 0.01 wt. % to 0.5 wt. %, from 0.01 wt. % to 0.2 wt. %, from 0.1 wt. % to 5 wt. %, from 0.1 wt. % to 4 wt. %, from 0.1 wt. % to 3 wt. %, from 0.1 wt. % to 2 wt. %, from 0.1 wt. % to 1 wt. %, from 0.5 wt. % to 5 wt. %, from 0.5 wt. % to 4 wt. %, from 0.5 wt. % to 3 wt. %, from 0.5 wt. % to 2 wt. %, from 0.5 wt. % to 1 wt. %, from 1 wt. % to 5 wt. %, from 1 wt. % to 4 wt. %, from 1 wt. % to 3 wt. %, from 1 wt. % to 2 wt. %, from 2 wt. % to 5 wt. %, from 2 wt. % to 4 wt. %, from 2 wt. % to 3 wt. %, from 3 wt. % to 5 wt. %, from 3 wt. % to 4 wt. %, or from 4 wt. % to 5 wt. % of the ZSM-5 zeolite seeds, based on the total weight of the slurry.
In embodiments, the slurry may comprise of from 0.5 wt. % to 4 wt. % of the basic compound, based on the total weight of the slurry. For instance, the slurry may comprise from 0.5 wt. % to 4 wt. %, from 0.5 wt. % to 3 wt. %, from 0.5 wt. % to 2 wt. %, from 0.5 wt. % to 1 wt. %, from 1 wt. % to 4 wt. %, from 1 wt. % to 3 wt. %, from 1 wt. % to 2 wt. %, from 2 wt. % to 4 wt. %, or from 2 wt. % to 3 wt. % of the basic compound, based on the total weight of the slurry. In embodiments the slurry may comprise from 0.5 wt. % to 4 wt. %, from 0.5 wt. % to 3 wt. %, from 0.5 wt. % to 2 wt. %, from 0.5 wt. % to 1 wt. %, from 1 wt. % to 4 wt. %, from 1 wt. % to 3 wt. %, from 1 wt. % to 2 wt. %, from 2 wt. % to 4 wt. %, or from 2 wt. % to 3 wt. % of NaOH, based on the total weight of the slurry.
In embodiments, the slurry may comprise of from 5 wt. % to 60 wt. % of the silica source, based on the total weight of the slurry. For instance, the slurry may comprise from 5 wt. % to 50 wt. %, from 5 wt. % to 40 wt. %, from 5 wt. % to 30 wt. %, from 5 wt. % to 20 wt. %, from 10 wt. % to 60 wt. %, from 10 wt. % to 50 wt. %, from 10 wt. % to 40 wt. %, from 10 wt. % to 30 wt. %, from 10 wt. % to 20 wt. %, from 20 wt. % to 60 wt. %, from 20 wt. % to 50 wt. %, from 20 wt. % to 40 wt. %, from 20 wt. % to 30 wt. %, from 30 wt. % to 60 wt. %, from 30 wt. % to 50 wt. %, or from 35 wt. % to 45 wt. % of the silica source., based on the total weight of the slurry.
In embodiments, the slurry may further comprise a templating agent. In embodiments, the templating agent may comprise an ammonium salt, such as but not limited to tetrapropylammonium bromide (TPABr) or centrimonium bromide (CTAB). In embodiments, the ammonium salt may be a bromide salt. In embodiments. The templating agent may comprise a poloxamer, such as but not limited to Pluronic® F-127 and Pluronic® P-123, commercially available from BASF Corporation. As used herein, the term “poloxamer” may refer to a triblock copolymer comprising a central hydrophobic chain of poly (propylene oxide) and two hydrophilic chains of poly (ethylene oxide). In embodiments, the templating agent may comprise an ammonium salt, a poloxamer, or combinations thereof. In embodiments, the templating agent may be selected from an ammonium salt, a poloxamer, and combinations thereof.
In embodiments, the slurry may comprise of from 0 wt. % to 3 wt. % of the templating agent, based on the total weight of the slurry. For instance, the slurry may comprise from 0.5 wt. % to 3 wt. %, from 0.5 wt. % to 2 wt. %, from 0.5 wt. % to 1 wt. %, from 1 wt. % to 3 wt. %, from 1 wt. % to 2 wt. %, or from 2 wt. % to 3 wt. % of the templating agent, based on the total weight of the slurry. In embodiments, the slurry may not include the templating agent.
Referring again to
In embodiments, hydrothermally treating the slurry may include heating the slurry for a duration of greater than or equal to 1 hour (hr), such as greater than or equal to 3 hr, greater than or equal to 6 hr, greater than or equal to 12 hr, greater than or equal to 24 hr, greater than or equal to 48 hr, greater than or equal to 72 hr, or greater than or equal to 96 hr. In embodiments, hydrothermally treating the slurry may include heating the slurry for a duration of from 1 hr to 5 days. Without intending to be bound by any particular theory, it is believed that increasing the duration that the slurry is hydrothermally treated may increase the mesopore surface area, the micropore surface area, or both the mesopore surface and micropore surface area of the ZSM-5 zeolite formed therefrom. Such increase in the surface area of the ZSM-5 zeolite may result in increasing a yield of propylene from the cracking of crude oil over the ZSM-5 zeolite of the present disclosure.
In embodiments, the hydrothermal product may be separated from the slurry after hydrothermal treatment. Methods known in the art may be used to separate the hydrothermal product from the slurry, such as but not limited to decantation, filtration, vacuum filtration, or other solid-liquid separation methods. After separation, the hydrothermal product may be washed with a solution, such as water. Washing may remove excess reagents from the surface of the hydrothermal product.
Referring again to
In embodiments, the ZSM-5 zeolite may be subjected to an ion exchange process to convert the ZSM-5 zeolite to the hydrogen form of the ZSM-5 zeolite, which is referred to in the present disclosure as the HZSM-5 zeolite. In embodiments, the ZSM-5 zeolite may be subjected an ion exchange process by contacting the ZSM-5 zeolite with a solution comprising ammonium nitrate (NH4NO3) or ammonium acetate. In embodiments, the ion exchange process conditions may include contacting the ZSM-5 zeolite with a solution having a concentration of about 1 molar (M) and in an amount from 1 milliliter (mL) to 100 mL of the solution per 1 gram (g) of the ZSM-5 zeolite, such as 10 mL of the about 1 M solution per 1 g of the ZSM-5 zeolite. In embodiments, the ion exchange process may include contacting the ZSM-5 zeolite with the solution for a duration of at least 10 minutes, such as about 3 hours.
In embodiments where the ZSM-5 zeolite is subjected to the ion exchange process, the ZSM-5 zeolite may be calcined after the ion exchange process.
In embodiments, calcining the ZSM-5 zeolite may comprise heating the ZSM-5 zeolite at a temperature of greater than or equal to 400° C., such as greater than or equal to 450° C., or greater than or equal to 475° C. In embodiments, calcining the ZSM-5 zeolite may comprise heating the ZSM-5 zeolite at a temperature of from 400° C. to 700° C., such as from 400° C. to 600° C., or from 400° C. to 550° C.
In embodiments, calcining the ZSM-5 zeolite may comprise heating the ZSM-5 zeolite for a duration of greater than or equal to 10 min, greater than or equal to 30 min, or greater than or equal to 2 hr. In embodiments, calcining the ZSM-5 zeolite may comprise heating the ZSM-5 zeolite for a duration of from 10 min to 6 hr.
In embodiments, the ZSM-5 zeolite may have a surface area of greater than or equal to 100 m2/g, such as greater than or equal to 150 m2/g, greater than or equal to 175 m2/g, greater than or equal to 200 m2/g, greater than or equal to 225 m2/g, greater than or equal to 250 m2/g, or even greater than or equal to 255 m2/g. In embodiments, the ZSM-5 zeolite may have a surface area of from 100 m2/g to 400 m2/g. For instance, in embodiments, the ZSM-5 zeolite may have a surface area of from 150 m2/g to 400 m2/g, from 200 m2/g to 400 m2/g, from 225 m2/g to 400 m2/g, from 250 m2/g to 400 m2/g, from 255 m2/g to 400 m2/g, from 100 m2/g to 300 m2/g, from 150 m2/g to 300 m2/g, from 200 m2/g to 300 m2/g, from 225 m2/g to 300 m2/g, from 250 m2/g to 300 m2/g, or from 255 m2/g to 300 m2/g. The surface area is determined using BET analysis.
In embodiments, the ZSM-5 zeolite may have an average mesopore volume of greater than or equal to 0.05 cm3/g, such as greater than or equal to 0.06 cm3/g, greater than or equal to 0.07 cm3/g, greater than or equal to 0.08 cm3/g, greater than or equal to 0.09 cm3/g, greater than or equal to 0.10 cm3/g, greater than or equal to 0.11 cm3/g, greater than or equal to 0.12 cm3/g, greater than or equal to 0.13 cm3/g, greater than or equal to 0.14 cm3/g, or greater than or equal to 0.15 cm3/g. In embodiments, the ZSM-5 zeolite may have an average mesopore volume of from 0.05 cm3/g to 2.0 cm3/g. For instance, in embodiments, the ZSM-5 zeolite may have an average mesopore volume of from 0.06 cm3/g to 3.0 cm3/g, from 0.07 cm3/g to 3.0 cm3/g, from 0.08 cm3/g to 3.0 cm3/g, from 0.09 cm3/g to 3.0 cm3/g, from 0.10 cm3/g to 3.0 cm3/g, from 0.11 cm3/g to 3.0 cm3/g, from 0.12 cm3/g to 3.0 cm3/g, from 0.13 cm3/g to 3.0 cm3/g, from 0.14 cm3/g to 3.0 cm3/g, from 0.15 cm3/g to 3.0 cm3/g, from 0.05 cm3/g to 2.0 cm3/g, from 0.06 cm3/g to 2.0 cm3/g, from 0.07 cm3/g to 2.0 cm3/g, from 0.08 cm3/g to 2.0 cm3/g, from 0.09 cm3/g to 2.0 cm3/g, from 0.10 cm3/g to 2.0 cm3/g, from 0.11 cm3/g to 2.0 cm3/g, from 0.12 cm3/g to 2.0 cm3/g, from 0.13 cm3/g to 2.0 cm3/g, from 0.14 cm3/g to 2.0 cm3/g, or from 0.15 cm3/g to 2.0 cm3/g. The average pore volume is determined using BJH analysis.
In embodiments, the ZSM-5 zeolite may have an average micropore volume of greater than or equal to 0.05 cm3/g, such as greater than or equal to 0.06 cm3/g, greater than or equal to 0.07 cm3/g, greater than or equal to 0.08 cm3/g, greater than or equal to 0.09 cm3/g, or greater than or equal to 0.10 cm3/g. In embodiments, the ZSM-5 zeolite may have an average micropore volume of from 0.05 cm3/g to 2.0 cm3/g. For instance, in embodiments, the ZSM-5 zeolite may have an average micropore volume of from 0.06 cm3/g to 2.0 cm3/g, from 0.07 cm3/g to 2.0 cm3/g, from 0.08 cm3/g to 2.0 cm3/g, from 0.09 cm3/g to 2.0 cm3/g, from 0.10 cm3/g to 2.0 cm3/g, from 0.05 cm3/g to 1.5 cm3/g, from 0.06 cm3/g to 1.5 cm3/g, from 0.07 cm3/g to 1.5 cm3/g, from 0.08 cm3/g to 1.5 cm3/g, from 0.09 cm3/g to 1.5 cm3/g, or from 0.10 cm3/g to 1.5 cm3/g. The average micropore volume is determined using BJH analysis.
In embodiments, the ZSM-5 zeolite may have an average total pore volume of greater than or equal to 0.10 cm3/g, such as greater than or equal to 0.15 cm3/g, greater than or equal to 0.20 cm3/g, greater than or equal to 0.25 cm3/g, or greater than or equal to 0.30 cm3/g. In embodiments, the ZSM-5 zeolite may have an average total pore volume of from 0.1 cm3/g to 0.5 cm3/g. For instance, in embodiments, the ZSM-5 zeolite may have an average total pore volume of from 0.2 cm3/g to 0.5 cm3/g, or from 0.3 cm3/g to 0.5 cm3/g. The average total pore volume is determined using BJH analysis.
In embodiments, the ZSM-5 zeolite may be substantially free of phosphorous. As used herein “substantially free of phosphorous” refers to the ZSM-5 zeolite comprising less than 0.001 percent by weight phosphorous, based on the total weight of the ZSM-5 zeolite. In embodiments, the ZSM-5 zeolite may be substantially free of any transition metals. As used herein “substantially free of any transition metals” refers to the ZSM-5 zeolite comprising less than 0.01 percent by weight transition metals, based on the total weight of the ZSM-5 zeolite. In embodiments, the ZSM-5 zeolite may be substantially free of any transition metal oxides. As used herein “substantially free of any transition metal oxides” refers to the ZSM-5 zeolite comprising less than 0.01 percent by weight transition metal oxides, based on the total weight of the ZSM-5 zeolite.
In embodiments, the ZSM-5 zeolite prepared by the methods of the present disclosure may be used in processes for cracking hydrocarbon feeds to produce light olefins, light aromatic compounds, or both. In embodiments, the process of cracking a hydrocarbon feed may include contacting the hydrocarbon feed with steam in the presence of the ZSM-5 zeolite or HZSM-5 zeolite of the present disclosure in a reactor under reaction conditions sufficient to cause at least a portion of the hydrocarbon feed to undergo one or more cracking reactions to produce a cracking effluent comprising light olefins, light aromatic compounds, or both.
In embodiments, the hydrocarbon feed may be a crude oil. As used in the present disclosure, the term “crude oil” refers to a mixture of petroleum liquids and gases, including impurities, such as sulfur-containing compounds, nitrogen-containing compounds, and metal compounds, extracted directly from a subterranean formation or received from a desalting unit without having any fractions, such as naphtha, separated by distillation. In other embodiments, the crude oil may be processed, such as separated by distillation, and the hydrocarbon feed may comprise a processed stream of the crude oil.
In embodiments, the hydrocarbon feed may have an American Petroleum Institute (API) gravity of from 15 degrees to 50 degrees, such as from 20 degrees to 50 degrees, from 25 degrees to 50 degrees, from 30 degrees to 50 degrees, or from 35 degrees to 50 degrees. For example, the hydrocarbon feed 102 may include an extra light crude oil, a light crude oil, a heavy crude oil, or combinations of these. In embodiments, the hydrocarbon feed may be an extra light crude oil, such as but not limited to an Arab extra light export crude oil.
In embodiments, the hydrocarbon feed may comprise from 10 wt. % to 70 wt. % naphtha, based on the total weight of the hydrocarbon feed. For instance, in embodiments, the hydrocarbon feed may comprise from 10 wt. % to 60 wt. %, from 10 wt. % to 50 wt. %, from 10 wt. % to 40 wt. %, from 10 wt. % to 30 wt. %, from 10 wt. % to 20 wt. %, from 20 wt. % to 70 wt. %, from 20 wt. % to 60 wt. %, from 20 wt. % to 50 wt. %, from 20 wt. % to 40 wt. %, from 20 wt. % to 30 wt. %, from 30 wt. % to 70 wt. %, from 30 wt. % to 60 wt. %, from 30 wt. % to 50 wt. %, from 30 wt. % to 40 wt. %, from 40 wt. % to 70 wt. %, from 40 wt. % to 60 wt. %, from 40 wt. % to 50 wt. %, from 50 wt. % to 70 wt. %, from 50 wt. % to 60 wt. %, or from 60 wt. % to 70 wt. % naphtha, based on the total weight of the hydrocarbon feed. As used in the present disclosure, the term “naphtha” refers to an intermediate mixture of hydrocarbon-containing materials derived from crude oil refining and having atmospheric boiling points from 25 degrees Celsius (° C.) to 220° C.
In embodiments, the hydrocarbon feed may comprise from 20 wt. % to 60 wt. % middle distillates, based on the total weight of the hydrocarbon feed. For instance, the hydrocarbon feed may comprise from 20 wt. % to 50 wt. %, from 20 wt. % to 40 wt. %, or from 20 wt. % to 30 wt. % middle distillates, based on the total weight of the hydrocarbon feed. As used in the present disclosure, the term “middle distillates” refers to an intermediate mixture of hydrocarbon-containing materials derived from crude oil refining and having atmospheric boiling points from 221° C. to 343° C.
In embodiments, the hydrocarbon feed may comprise from 10 wt. % to 70 wt. % heavy distillates, based on the total weight of the hydrocarbon feed. For instance, in embodiments, the hydrocarbon feed may comprise from 10 wt. % to 60 wt. %, from 10 wt. % to 50 wt. %, from 10 wt. % to 40 wt. %, from 10 wt. % to 30 wt. %, from 10 wt. % to 20 wt. %, from 20 wt. % to 70 wt. %, from 20 wt. % to 60 wt. %, from 20 wt. % to 50 wt. %, from 20 wt. % to 40 wt. %, from 20 wt. % to 30 wt. %, from 30 wt. % to 70 wt. %, from 30 wt. % to 60 wt. %, from 30 wt. % to 50 wt. %, from 30 wt. % to 40 wt. %, from 40 wt. % to 70 wt. %, from 40 wt. % to 60 wt. %, from 40 wt. % to 50 wt. %, from 50 wt. % to 70 wt. %, from 50 wt. % to 60 wt. %, or from 60 wt. % to 70 wt. % heavy distillates, based on the total weight of the hydrocarbon feed. As used in the present disclosure, the term “heavy distillates” refers to an intermediate mixture of hydrocarbon-containing materials derived from crude oil refining and having atmospheric boiling points of greater than 343° C.
In embodiments, the reactor may include a tank or tubular reactor configured to operate as a batch reactor, a continuous stirred-tank reactor (CSTR), or a plug flow reactor. Example reactors include packed bed reactors such as fixed bed reactors, and fluidized bed reactors. One or more reaction zones may be disposed in a reactor. For example, a packed bed reactor with multiple catalyst beds may have multiple reaction zones, where each reaction zone is defined by the area of each catalyst bed.
In embodiments, a cracking catalyst may comprise the ZSM-5 zeolite produced by the methods of the present disclosure. The cracking catalyst can include the ZSM-5 zeolite or the HZSM-5 zeolite (hydrogen form). In embodiments, the cracking catalyst can consist of or consist essentially of the ZSM-5 zeolite or the HZSM-5 zeolite.
In embodiments, the process may include contacting the hydrocarbon feed with the steam in the presence of the ZSM-5 zeolite or the HZSM-5 zeolite in the reactor for a residence time of from 1 second to 60 seconds, such as from 5 seconds to 30 seconds, or about 10 seconds. In embodiments, the reactor may be operated at a weight hourly space velocity (WHSV) of from 0.1 h−1 to 25 h−1. As used in the present disclosure, the “WHSV” is defined as the weight of the hydrocarbon feed flowing into the reactor per unit weight of the catalyst composition in the reactor per hour. For instance, in embodiments, the reactor may be operated at a weight hourly space velocity (WHSV) of from 0.1 h−1 to 20 h−1, from 0.1 h−1 to 10 h−1, from 0.1 h−1 to 5 h−1, from 1 h−1 to 25 h−1, from 1 h−1 to 20 h−1, from 1 h−1 to 10 h−1, from 1 h−1 to 5 h−1, from 2 h−1 to 25 h−1, from 2 h-1 to 20 h−1, from 2 h−1 to 10 h−1, from 2 h−1 to 5 h−1, or from 2 h−1 to 4 h−1.
In embodiments, water may be injected into the reactor. The water may be converted to steam prior to contacting the hydrocarbon feed or upon contact with the hydrocarbon feed. The water may be delivered to the reactor at a gas hourly space velocity of greater than or equal to 0.1 per hour (h-1), greater than or equal to 0.5 h−1, greater than or equal to 1 h−1, greater than or equal to 5 h−1, greater than or equal to 6 h−1, greater than or equal to 10 h−1, or even greater than or equal to 15 h−1. The water may be introduced to the reactor at a gas hourly space velocity of less than or equal to 100 h−1, less than or equal to 75 h−1, less than or equal to 50 h−1, less than or equal to 30 h 1, or less than or equal to 20 h−1. The water may be introduced to the reactor at a gas hourly space velocity of from 0.1 h−1 to 100 h−1, from 0.1 h−1 to 75 h−1, from 0.1 h−1 to 50 h−1, from 0.1 h−1 to 30 h-1, from 0.1 h−1 to 20 h−1, from 1 h−1 to 100 h−1, from 1 h−1 to 75 h−1, from 1 h−1 to 50 h−1, from 1 h-1 to 30 h−1, or from 1 h−1 to 20 h−1.
The steam produced from injection of the water into the reactor may reduce the hydrocarbon partial pressure, which may have the dual effects of increasing yields of light olefins (e.g., ethylene, propylene and butylene) as well as reducing coke formation on the ZSM-5 zeolite or cracking catalyst comprising the ZSM-5 zeolite. Without intending to be bound by any particular theory, it is believed that light olefins like propylene and mixed butenes are mainly generated from catalytic cracking reactions following the carbonium ion mechanism, and as these are intermediate products, they can undergo secondary reactions such as hydrogen transfer and aromatization (leading to coke formation). The steam may increase the yield of light olefins by suppressing these secondary bi-molecular reactions, and may reduce the concentration of reactants and products, which favor selectivity towards light olefins. The steam may also suppress secondary reactions that are responsible for coke formation on the catalyst surface, which is good for catalysts to maintain high average activation. These factors may show that a large steam-to-oil weight ratio may be beneficial to the production of light olefins.
In embodiments, the reactor may be operated at a temperature of from 500° C. to 700° C., such as from 550° C. to 700° C., from 600° C. to 700° C., or from 650° C. to 700° C.
In embodiments, the product effluent may comprise greater than or equal to 20 wt. % light olefins, based on the total weight of the product effluent. For instance, the product effluent may comprise greater than or equal to 25 wt. %, greater than or equal to 30 wt. %, greater than or equal to 35 wt. %, or even greater than or equal to 37 wt. % light olefins. In embodiments, the product effluent may comprise of from 20 wt. % to 60 wt. % light olefins, such as from 20 wt. % to 50 wt. %, from 20 wt. % to 40 wt. %, from 30 wt. % to 60 wt. %, from 30 wt. % to 50 wt. %, from 30 wt. % to 40 wt. %, from 35 wt. % to 60 wt. %, from 35 wt. % to 50 wt. %, or from 35 wt. % to 40 wt. % light olefins.
Without intending to be bound by any particular theory, it is believed that the ZSM-5 zeolites and cracking catalysts comprising the ZSM-5 zeolites described herein may be used to crack a hydrocarbon feed and produce a product effluent having a greater amount of light olefins compared to methods using conventional catalysts derived from kaolin clay comprising less than 10 wt. % halloysite.
A first aspect of the present disclosure is directed to a method of forming a ZSM-5 zeolite, the method comprising calcining one or more clay mineral compositions to form metakaolin, forming a slurry by combining at least the metakaolin, ZSM-5 zeolite seeds, a basic compound, and a silica source, hydrothermally treating the slurry to form a hydrothermal product, and calcining the hydrothermal product to form the ZSM-5 zeolite. The one or more clay mineral compositions comprise greater than or equal to 10 wt. % halloysite.
A second aspect of the present disclosure may include the first aspect, wherein the one or more clay mineral compositions comprise of from 50 weight percent (wt. %) to 100 wt. % halloysite, based on the total weight of the one or more clay mineral compositions.
A third aspect of the present disclosure may include either one of the first or second aspects, wherein the one or more clay mineral compositions comprise from 0 wt. % to 90 wt. % kaolinite, based on the total weight of the one or more clay mineral compositions.
A fourth aspect of the present disclosure may include any one of the first through third aspects, wherein calcining the one or more clay mineral compositions comprises heating the one or more clay mineral compositions at a temperature of greater than or equal to 500° C.
A fifth aspect of the present disclosure may include any one of the first through fourth aspects, wherein the metakaolin has an average surface area of greater than 30 m2/g.
A sixth aspect of the present disclosure may include any one of the first through fifth aspects, wherein the metakaolin has an average pore volume of greater than 0.15 centimeters cubed per gram (cm3/g).
A seventh aspect of the present disclosure may include any one of the first through sixth aspects, wherein the ZSM-5 zeolite seeds have an average silica to alumina ratio of from 10 to 280.
An eighth aspect of the present disclosure may include any one of the first through seventh aspects, wherein the slurry further comprises a templating agent.
A ninth aspect of the present disclosure may include the eighth aspect, wherein the templating agent comprises an ammonium salt, a poloxamer, or combinations thereof.
A tenth aspect of the present disclosure may include either one of the eighth or ninth aspects, wherein the templating agent comprises tetrapropylammonium bromide.
An eleventh aspect of the present disclosure may include any one of the eighth through tenth aspects, wherein the slurry comprises from 0.1 wt. % to 5 wt. % of the templating agent, based on the total weight of the slurry.
A twelfth aspect of the present disclosure may include any one of the first through eleventh aspects, wherein hydrothermally treating the slurry includes heating the slurry at a temperature of greater than or equal to 100° C.
A thirteenth aspect of the present disclosure may include any one of the first through twelfth aspects, wherein hydrothermally treating the slurry includes heating the slurry at a temperature of greater than or equal to 100° C. for a duration of greater than or equal to 48 hours.
A fourteenth aspect of the present disclosure may include any one of the first through thirteenth aspects, wherein calcining the hydrothermal product comprises heating the hydrothermal product at a temperature of greater than or equal to 400° C.
A fifteenth aspect of the present disclosure may include any one of the first through fourteenth aspects, further comprising ion-exchanging the ZSM-5 zeolite with a solution comprising ammonium nitrate or ammonium acetate to produce a hydrogen form of the ZSM-5 zeolite.
A sixteenth aspect of the present disclosure may include any one of the first through fifteenth aspects, wherein the slurry comprises from 1 wt. % to 3 wt. % of the metakaolin, from 0.01 wt. % to 0.5 wt. % of the ZSM-5 zeolite seeds, from 1 wt. % to 3 wt. % of the basic compound, and from 30 wt. % to 50 wt. % of the silica source, where the weight percentages are based on the total weight of the slurry.
A seventeenth aspect of the present disclosure is directed to a ZSM-5 zeolite prepared by the method of any one of the first through sixteenth aspects.
An eighteenth aspect of the present disclosure may include the seventeenth aspect wherein the ZSM-5 zeolite has an average mesopore volume of greater than or equal to 0.10 cubic centimeters cubed per gram (cm3/g).
A nineteenth aspect of the present disclosure may include any one of the seventeenth aspect or eighteenth aspect, wherein the ZSM-5 zeolite has an average micropore volume of greater than or equal to 0.08 cubic centimeters cubed per gram (cm3/g).
A twentieth aspect of the present disclosure may include any one of the seventeenth through nineteenth aspects, wherein the ZSM-5 zeolite has an average total pore volume of greater than or equal to 0.20 cubic centimeters cubed per gram (cm3/g).
A twenty first aspect of the present disclosure may include any one of the seventeenth through twentieth aspects, where the ZSM-5 zeolite is substantially free of phosphorous, transition metals, and transition metal oxides.
A twenty second aspect of the present disclosure is directed to a process of cracking a hydrocarbon feed comprising contacting the hydrocarbon feed with steam in the presence of a cracking catalyst comprising the ZSM-5 zeolite of any one of the seventeenth through twenty first aspects in a reactor under reaction conditions sufficient to cause at least a portion of the hydrocarbon feed to undergo one or more cracking reactions to produce a cracking effluent comprising light olefins, light aromatic compounds, or both
A twenty third aspect of the present disclosure may the twenty second aspect, wherein the hydrocarbon feed is crude oil.
A twenty fourth aspect of the present disclosure may include any one of the twenty second or twenty third aspects, wherein where the hydrocarbon feed has an American Petroleum Institute gravity of from 15 degrees to 50 degrees
A twenty fifth aspect of the present disclosure may include any one of the twenty second through twenty fourth aspects, comprising contacting the hydrocarbon feed with the steam in the presence of the cracking catalyst at a temperature of from 500° C. to 700° C.
A twenty sixth aspect of the present disclosure may include any one of the twenty second through twenty fifth aspects, comprising contacting the hydrocarbon feed with the steam in the presence of the cracking catalyst for a residence time of from 0.1 seconds to 60 seconds.
A twenty seventh aspect of the present disclosure may include any one of the twenty second through twenty sixth aspects, where the cracking catalyst consists of the ZSM-5 zeolite.
The various embodiments disclosed herein will be further clarified by the following examples. The examples are illustrative in nature, and should not be understood to limit the embodiments disclosed herein.
In Comparative Example A, metakaolin was prepared by calcining kaolin clay comprising hydrated aluminum silicate (kaolinite). The kaolin clay of Comparative Example A is commercially available as Kaolin (K7375) from Sigma Aldrich. Metakaolin was formed by heating the kaolin clay in an oven at a ramp rate of 5° C./min until reaching 700° C. The sample was calcined for 2 hours at 700° C. to form metakaolin, denoted as Comparative Example A.
In Example 1, metakaolin was prepared by calcining a kaolin clay comprising halloysite. In Examples 1-1, 1-2, and 1-3, the calcining time was varied.
To prepare Example 1-1, kaolin clay comprising halloysite was calcined. The kaolin clay of Example 1 is commercially available as halloysite nanoclay (685445) from Sigma Aldrich. Metakaolin was formed by heating naturally occurring kaolin clay comprising halloysite in an oven at a ramp rate of 5° C./min until reaching 700° C. The sample was calcined for 30 min at 700° C. to form metakaolin, denoted as Example 1-1.
Example 1-2 was prepared according to Example 1-1, but the sample was calcined for 1 hour at 700° C. to form metakaolin, denoted as Example 1-2.
Example 1-3 was prepared according to Example 1-1, but the sample was calcined for 2 hour at 700° C. to form metakaolin, denoted as Example 1-3.
In Comparative Example B, ZSM-5 zeolites were prepared using metakaolin formed from kaolinite. In particular, the metakaolin was formed according to Comparative Example A.
To prepare Comparative Example B-1, an alkaline mixture was prepared by mixing 10 mL of distilled water and 1 gram of sodium hydroxide (NaOH), which was stirred for 20 min. Comparative Example A (1.0 g) was dispersed in deionized water (10 mL) and stirred for 1 hour to form a metakaolin dispersion. The metakaolin dispersion was mixed with the alkaline mixture to form a metakaolin alkaline mixture. Silica particles (Ludox® AS-40 colloidal silica, (Cat. No. 420840), available from Sigma Aldrich) in an amount of 22.83 g were added dropwise to the metakaolin alkaline mixture and stirred for 1 hour to form a metakaolin-nanosilica mixture. The metakaolin-nanosilica mixture was dispersed in deionized water (10 mL) and stirred for 16 hours. An initial ZSM-5 zeolite having a silica to alumina ratio (SAR) of 80 (Product No. CBV 8014 ZSM-5 zeolite, available from Zeolyst International) in an amount of 0.09 g was added to the metakaolin-nanosilica solution mixture to act as seeds that facilitated the zeolite growth, and was stirred for 2 hours. Tetrapropylammonium bromide (TPABr) (0.5 g) was added to the seeded metakaolin-nanosilica mixture to form the slurry, and the slurry was kept at room temperature and not stirred for 12 hours. The slurry was transferred to a Teflon-lined autoclave and aged at 175° C. for 72 hours to obtain the kaolinite-based zeolite. The kaolinite-based zeolite was extracted from the solution by vacuum filtration washed three times with deionized water, and then dried at 100° C. for 12 h. The washed and dried zeolite was calcined at 550° C. for 6 hours. The calcined zeolite was ion exchanged twice using 10 mL of 1M NH4NO3 solution per gram of zeolite at 80° C. for 3 hours. The ion-exchanged zeolite was washed and calcined at 500° C. for 2 hours. The final zeolite product is denoted as Comparative Example B-1.
Comparative Example B-2 was prepared according to the method described in Comparative Example B-1, but the TPABr was not present in the slurry. The final zeolite is denoted as Comparative Example B-2.
In Example 2. ZSM-5 zeolites were prepared using metakaolin formed from halloysite. In particular, the metakaolin was formed according to the method described in Example 1-3.
To prepare Example 2-1, an alkaline mixture was prepared by mixing 10 mL of distilled water and 1 gram of sodium hydroxide (NaOH), which was stirred for 20 min. Example 1-3 (1.0 g) was dispersed in deionized water (10 ml) and stirred for 1 hour to form a metakaolin dispersion. The metakaolin dispersion was mixed with the alkaline mixture to form a metakaolin alkaline mixture. Silica particles (Ludox® AS-40 colloidal silica, (Cat. No. 420840), available from Sigma Aldrich) in an amount of 22.83 g were added dropwise to the metakaolin alkaline mixture and stirred for 1 hour to form a metakaolin-nanosilica mixture. The metakaolin-nanosilica mixture was dispersed in deionized water (10 mL) and stirred for 16 hours. An initial ZSM-5 zeolite having a silica to alumina ratio (SAR) of 80, a surface area of 358 m2/g, and pore volume of 0.22 cm3/g (Product No. CBV 8014 ZSM-5 zeolite, available from Zeolyst International) in an amount of 0.09 g was added to the metakaolin-nanosilica solution mixture to act as seeds that facilitated the zeolite growth, and was stirred for 2 hours. Tetrapropylammonium bromide (TPABr) (0.5 g) was added to the seeded metakaolin-nanosilica mixture to form the slurry, and the slurry was kept at room temperature and not stirred for 12 hours. The slurry was transferred to a Teflon-lined autoclave and aged at 175° C. for 72 hours to obtain the halloysite-based zeolite. The halloysite-based zeolite was extracted from the solution by vacuum filtration washed three times with deionized water, and then dried at 100° C. for 12 h. The washed and dried zeolite was calcined at 550° C. for 6 hours. The calcined zeolite was ion exchanged twice using 10 mL of 1M NH4NO3 solution per gram of zeolite at 80° C. for 3 hours. The ion-exchanged zeolite was washed and calcined at 500° C. for 2 hours. The final ZSM-5 zeolite is denoted as Example 2-1.
To prepare Example 2-1, an alkaline mixture was prepared by mixing 10 mL of distilled water and 1 gram of sodium hydroxide (NaOH), which was stirred for 20 min. Example 1-3 (1.0 g) was dispersed in deionized water (10 ml) and stirred for 1 hour to form a metakaolin dispersion. The metakaolin dispersion was mixed with the alkaline mixture to form a metakaolin alkaline mixture. Silica particles (Ludox® AS-40 colloidal silica, (Cat. No. 420840), available from Sigma Aldrich) in an amount of 22.83 g were added dropwise to the metakaolin alkaline mixture and stirred for 1 hour to form a metakaolin-nanosilica mixture. The metakaolin-nanosilica mixture was dispersed in deionized water (10 mL) and stirred for 16 hours. An initial ZSM-5 zeolite having a silica to alumina ratio (SAR) of 80 (Product No. CBV 8014 ZSM-5 zeolite, available from Zeolyst International) in an amount of 0.09 g was added to the metakaolin-nanosilica solution mixture to act as seeds that facilitated the zeolite growth, and was stirred for 2 hours. Tetrapropylammonium bromide (TPABr) (0.5 g) was added to the seeded metakaolin-nanosilica mixture to form the slurry, and the slurry was kept at room temperature and not stirred for 12 hours. The slurry was transferred to a Teflon-lined autoclave and aged at 175° C. for 72 hours to obtain the halloysite-based zeolite. The halloysite-based zeolite was extracted from the solution by vacuum filtration washed three times with deionized water, and then dried at 100° C. for 12 h. The washed and dried zeolite was calcined at 550° C. for 6 hours. The calcined zeolite was ion exchanged twice using 10 mL of 1M NH4NO3 solution per gram of zeolite at 80° C. for 3 hours. The ion-exchanged zeolite was washed and calcined at 500° C. for 2 hours. The final ZSM-5 zeolite is denoted as Example 2-1.
Example 2-2 was prepared according to Example 2-1, but the slurry was aged for 96 hours instead of 72 hours. The ZSM-5 zeolite is denoted as Example 2-2.
Example 2-3 was prepared according to Example 2-1, but the slurry was aged for 120 hours instead of 72 hours. The ZSM-5 zeolite is denoted as Example 2-3.
Example 2-4 was prepared according to Example 2-1, but the TPABr was not present in the slurry. The ZSM-5 zeolite is denoted as Example 2-4.
In Example 3, the metakaolin formed in Comparative Example A and Example 1-3 were characterized to distinguish differences between the metakaolin based on the kaolin material calcined.
Referring to
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Further, the surface areas, pore volumes, and pore distributions of the Examples and Comparative Examples were measured, and are summarized in Table 1. A t-plot was used to differentiate microporous and mesoporous surface area. MicroSA refers to the microporous surface area. MicroPV refers to the microporous pore volume. MesoPV refers to the mesoporous pore volume. PSD refers to the pore size distribution.
Referring to
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Referring to
Referring to
Ammonia temperature programmed desorption (NH3-TPD) analysis was carried out to characterize the acid strength of the Examples and Comparative Examples. Typically, two desorption peaks in the range of 100-300° C. and above 350° C. were observed in all the analyzed samples. A low desorption peak between 100-300° C. corresponds to weak acid sites (almost Lewis), while high temperature desorption between 400-550° C. is ascribed to strong acid sites (almost Bronsted). A summary of the results is presented in Table 2.
Referring to
Referring to
Referring to
The reaction product streams from the cracking reaction over various zeolites were analyzed. The yield analysis for commercial zeolites ZSM-5 (23) and ZSM-5 (80), Example 2-1, and Comparative Examples B-1 and B-2 are listed in Table 5. As shown, Example 2-1 had the highest conversion yield of ethylene (19.2 wt. %) and propylene (18.1 wt. %) compared to the commercial ZSM-5 (23) catalyst (CBV 2314, Zeolyst International) and ZSM-5 (80) (CBV 8014, Zeolyst International) catalysts. Example 2-1 also had a higher total yield of ethylene and propylene (C27+C3=) (37.3 wt. %) compared to that Comparative Example B-1 and Comparative Example B-2 (36.1 wt. % and 36.7 wt. %, respectively). These results demonstrate that zeolites derived from kaolin clay comprising halloysite can provide improved catalytic cracking compared to conventional zeolites.
The reaction product streams from the cracking reaction over a comparative catalyst and Examples 2-1, 2-2, and 2-3 in combination with Ecat (Equilibrium catalyst, W.R. Grace & Co-Conn) were analyzed. Examples 2-1, 2-2, and 2-3 were steam deactivated at 810° C. for 6 hr before using in the reactor. In Example 5-1, 5-2, and 5-3, 75 wt. % Ecat and 25 wt. % of Examples 2-1, 2-2, and 2-3, respectively were loaded in the reactor. Comparative Example 5-A is commercial catalyst (UMIX75, W.R. Grace & Co-Conn) comprising 75 wt. % equilibrium catalyst (Ecat) with USY zeolite and 25 wt. % OlefinsUltra® provided by W. R. Grace & Co-Conn. Table 6 provides the summarized results of the reaction product streams from the cracking reaction. As shown, these results demonstrate that cracking the AXL oil over Examples 5-1, 5-2, and 5-3 had a higher yield of ethylene, propylene, and butylene compared to Comparative Example 5-A.
It is noted that one or more of the following claims utilize the term “where” as a transitional phrase. For the purposes of defining the present technology, it is noted that this term is introduced in the claims as an open-ended transitional phrase that is used to introduce a recitation of a series of characteristics of the structure and should be interpreted in like manner as the more commonly used open-ended preamble term “comprising.”
It should be understood that any two quantitative values assigned to a property may constitute a range of that property, and all combinations of ranges formed from all stated quantitative values of a given property are contemplated in this disclosure. The subject matter disclosed herein has been described in detail and by reference to specific embodiments. It should be understood that any detailed description of a component or feature of an embodiment does not necessarily imply that the component or feature is essential to the particular embodiment or to any other embodiment. Further, it should be apparent to those skilled in the art that various modifications and variations can be made to the described embodiments without departing from the spirit and scope of the claimed subject matter. Since modifications, combinations, sub-combinations, and variations of the disclosed embodiments, which incorporate the spirit and substance disclosed herein, may occur to persons of ordinary skill in the art, the scope disclosed herein should be construed to include everything within the scope of the appended claims and their equivalents.
