Recent Trends in Fluid Catalytic Cracking Patents, Part IV: Cracking Catalysts

Fluid Catalytic Cracking Patents (IV): Cracking Catalysts – 2012-2013 [1]

This is the fourth article in a review of recent patents in the area of Fluid Catalytic Cracking (FCC).  The first article reviewed patents on catalyst additives, and demonstrated that relatively few patents had recently issued on FCC additives (e.g., gasoline sulfur reduction catalysts), likely reflecting the current use of gas oil hydrotreaters and naphtha hydrotreaters/desulphurizers, which reduce the need for such additives.  The second article reviewed patents related to zeolites, and demonstrated that trends in this area reflected an emphasis on the mesoporosity of those zeolites.  The third article reviewed patents on cyclones, and showed that patenting trends in this area appear to be primarily related to improvements in performance for conventional designs, consolidation of other reactor operations (stripping) to the cyclone, or design of separation systems usable in a variety of existing regenerator designs.  The current article covers recent patents relating to cracking catalysts.  There are relatively few of these patents, and not enough to designate any trends as a whole, although as mentioned previously there are patenting trends in the zeolite portion of the catalyst.

The group of patents covered in this article have been given the designation, Cracking Catalyst.  Several of these could have been included in the previous article relating to zeolites, but possessed enough additional structure as to the catalyst system as a whole that they deserved to be discussed separately.  However, there does not appear to be enough relatedness in the patents to reliably designate any trends.  Two of the patents in this group, U.S. 8,137,534 and 8,614,160, relate to tri-zeolite systems designed for coke selective propylene production.  U.S. 8,278,235 relates to a cracking catalyst prepared in such a way as to have a substantially inert core and an active shell containing zeolite and matrix.  This type of system would be targeted at short contact time operations because as the patent explains, “the diffusion path length through the active shell is shorter than that in a conventional catalyst that doesn’t have an inert core, but does have the same diameter.”  U.S. 8,524,630 relates to a method for producing a mesoporous alumina composition which can be used either as a catalyst or as a support for a catalyst.  As discussed in the previous article on zeolites, the mesoporous alumina would be expected to provide bottoms upgrading capability.  Finally, U.S. 8,614,159 relates to a method of reusing treated spent equilibrium catalyst (ECAT).  The addition of ECAT is widely used commercially to maintain both the FCC catalyst unit inventory and heat balance, as well as to control contaminants deposited onto the catalyst within the unit inventory.    Successful treatment of the ECAT would not only potentially improve the quality of ECAT by tailoring its performance characteristics to that required in a target unit, but would also potentially allow recovery of valuable elements contained on the ECAT.

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 The patents related to cracking catalysts are summarized below.  Table 1 lists relevant information in the patents.  Table 2 contains a representative independent claim from each.

Cracking Catalyst

U.S. Patent No. 8,137,534, assigned to UOP LLC, generally relates to a process for fluid catalytic cracking in a reaction zone with a cracking catalyst composition to produce C₁-C₄ hydrocarbons including propylene and gasoline.  The cracking catalyst comprises: (1) a large pore zeolite; (2) a medium pore zeolite having a silica to alumina framework molar ratio of 30 to 60; and (3) a siliceous zeolite having a silica to alumina framework molar ratio of at least about 100.  The large pore zeolite has pores with an effective pore diameter of greater than 0.7 nanometers that are defined by 10- or more-membered ring, such as synthetic zeolites like zeolite X, zeolite Y, mordenite, and faujasite.  The medium pore zeolite has pores with an effective pore diameter of less than or equal to 0.7 nm and which are defined by 10 or fewer membered ring pores.  The siliceous zeolite have structures with 10-membered ring pores, such as MFI, MEL, NES, SFG MWW, and ITH structures.  The three zeolites can also contain a binder or matrix, and may be present as separate bound catalysts.  The patent contains a single independent claim which is summarized in Table 3.

U.S. Patent No. 8,278,235, assigned to BASF Corporation, generally relates to a fluidizable cracking catalyst comprising: (1) 5 to 50% by volume of an inert core comprising mullite; and (2) 50 to 95% by volume of an active shell comprising a NaY zeolite catalyst and a matrix.    The NaY catalyst is crystallized in the active shell by spray-drying a slurry containing microhpheres of mullite, a NaY precursor and matrix.  The cracking catalyst retains at least 45% of its original zeolite surface area through standard steaming (4 hours at 1500°F, 1 atm 100% steam).  The patent contains three independent claims (1, 13 and 21).  Claim 1 is summarized in Table 3.

U.S. Patent No. 8,524,630, assigned to ExxonMobil Research and Engineering Company, generally relates to a process for making a mesoporous alumina composition comprising aluminum, at least one rare earth element and phosphorous.  The process includes (a) forming a reaction mixture of at least one rare earth element, a source of aluminum, a source of phosphorus, and a mesopore templating agent in a liquid medium; (b) precipitating the components of the reaction mixure so that residual mesopore templating agent is within the pores; (c) separating liquid from the as-synthesized form of the mesoporous alumina composition; (d) optionally removing a portion of the mesopore templating agent from the as-synthesized form of mesoporous alumina composition of step (c) by solvent extraction; and (e) calcining the as-synthesized form of the mesoporous alumina composition of step (c) or (d) under calcination conditions to form a calcined form of the mesoporous alumina composition.  The calcination conditions are sufficient to remove the residual mesopore templating agent and cause condensation reactions with hydroxyl groups to liberate H₂O.  The molar ratio of Al:P:RE in the reaction mixture are 5-10:1:0.5:-1.  The mesoporous alumina composition of step e has an average pore size of from 45 Angstroms to 80 Angstroms and a surface are of 150 to 300 m²/g.  The patent contains two independent claims (1 and 9).  Claim 1 is summarized in Table 3.

U.S. Patent No. 8,614,159 generally relates to a method of re-using spent FCC catalyst comprising aluminum and at least one rare earth element, the method comprises reacting the spent FCC catalyst with an extracting agent to extract at least a portion of the at least one rare earth element from the FCC catalyst while extracting no more than half of the aluminum.  The extracting agent is a liquid solution having a pH of either less than approximately 6 or greater than approximately 8.  The treated FCC catalyst is then used in an additional FCC process.  The patent contains three independent claims (1, 18 and 33).  Claim 1 is listed in Table 3.

U.S. Patent No. 8,614,160, assigned to UOP LLC, generally relates to a catalyst blend  of separate catalyst particles of (1) Y zeolite; (2) ZSM-5 zeolite; and (3) a silicalite having a silica to alumina framework molar ratio from about 500 to 2000.  The separate catalyst particles of silicalite contain from about 20% to about 75% by weight of silicalite.  The silicalite is present in the catalyst blend in an amount from about 1% to about 10%.  The patent is a divisional of U.S. Patent No. 8,137,534 and contains a single independent claim which is summarized in Table 3.

Table 1
FCC Patents—Cracking Catalysts

Patent Number	Inventor	Assignee	Title	Issue Date
U.S. 8,137,534	Upson et al.	UOP LLC	Catalyst Compositions For Improved Fluid Catalytic Cracking (FCC) Processes Targeting Propylene Production	March 20, 2012
U.S. 8,278,235	Stockwell et al.	BASF Corporation	Structurally Enhanced Cracking Catalysts	October 2, 2012
U.S. 8,524,630	Wang et al.	ExxonMobil Research and Engineering Company	Mesoporous Aluminas Stabilized With Rare Earth And Phosphorous	September 3, 2013
U.S. 8,614,159	Vierheilig		Methods Of Re-Using A Spent FCC Catalyst	December 24, 2013
U.S. 8,614,160	Upson, et al.	UOP LLC	Catalyst Compositions For Improved Fluid Catalytic Cracking (FCC) Processes Targeting Propylene Production	December 24, 2013

Table 2.
Cracking Catalysts Claims

Patent Number	Independent Claim
U.S. 8,137,534	Claim 1.  A fluid catalytic cracking (FCC) process, comprising: contacting a heavy hydrocarbon stream with a cracking catalyst composition in an FCC reaction zone to provide an effluent stream comprising C1-C4 hydrocarbons including propylene and gasoline boiling range hydrocarbons, wherein said cracking catalyst composition comprises (i) a large pore zeolite, (ii) a medium pore zeolite having a silica to alumina framework molar ratio ranging from about 30 to about 60, and (iii) a third, siliceous zeolite having a silica to alumina framework molar ratio of at least about 100 for a reduced production of dry gas.
U.S. 8,278,235	Claim 1.  A fluidizable cracking catalyst, comprising: from about 5% to less than 50% by volume a substantially inert core comprising mullite; and from 50% to about 95% by volume of an active shell comprising a NaY zeolite catalyst and a matrix, wherein the NaY zeolite catalyst is crystallized in the active shell after a slurry containing microspheres of mullite, NaY zeolite precursor, and matrix precursor is spray-dried, wherein the cracking catalyst maintains at least about 45% of original NaY zeolite surface area through standardized steaming.
U.S. 8,524,630	Claim 1  A method for making a mesoporous alumina composition comprising, in addition to aluminum (Al), at least one rare earth element (RE) and phosphorus (P), said method comprising the steps of: (a) forming a reaction mixture comprising a source of at least one rare earth element, a source of aluminum, a source of phosphorus, and a mesopore templating agent in a liquid medium; (b) maintaining said reaction mixture of step (a) under conditions sufficient to precipitate said sources of rare earth element, aluminum, phosphorus and said mesopore templating agent to form an as-synthesized form of said mesoporous alumina composition comprising residual mesopore templating agent within pores of said mesoporous oxide composition; (c) separating said liquid from the as-synthesized form of said mesoporous alumina composition obtained in step (b); (d) optionally, removing at least a portion said mesopore templating agent from said as-synthesized form of said mesoporous alumina composition of step (c) by solvent extraction; and (e) calcining said as-synthesized form of said mesoporous alumina composition of step (c) or step (d) under calcination conditions to form a calcined form of said mesoporous alumina composition, wherein said calcination conditions are sufficient to remove any residual mesopore templating agent and to cause condensation reactions with hydroxyl groups to liberate H2O; wherein a molar ratio of Al:P:RE in said reaction mixture of step (a) is 5-10:1:0.5-1, and wherein said calcined form of said mesoporous alumina composition of step (e) has an average pore size of from 45 Angstroms to 80 Angstroms, and a surface area of 150 to 300 m.sup.2/g.
U.S. 8,614,159	Claim 1.  A method of re-using a spent fluid catalytic cracking (FCC) catalyst, previously used in an FCC process, in an additional FCC process, the method comprising the steps of: providing FCC catalyst that has been utilized in an FCC process, defined as spent FCC catalyst, wherein said spent FCC catalyst includes both aluminum and at least one rare earth element therein; reacting the spent FCC catalyst with an extracting agent to extract at least a portion of the at least one rare earth element from the spent FCC catalyst, while extracting no more than half of the aluminum from the spent FCC catalyst, wherein the extracting agent is a liquid solution having a pH of either less than approximately 6 or greater than approximately 8; and after performing the reacting step, using the reacted spent FCC catalyst in an additional FCC process.
U.S. 8,614,160	Claim 1  A catalyst blend comprising separate catalyst particles of (i) Y zeolite, (ii) ZSM-5 zeolite, and (iii) silicalite having a silica to alumina framework molar ratio from about 500 to about 2000, wherein (a) said separate catalyst particles of silicalite contain from about 20% to about 75% by weight of silicalite and (b) said silicalite is present in said catalyst blend in an amount from about 1% to about 10% by weight.