FIELD OF THE INVENTION

[0001] This disclosure relates to methods and systems for converting hydrocarbons to a hydrocarbon product in the presence of nitrogen (N) and a catalyst comprising substantially no intentionally added chlorine, particularly converting a naphtha stream to a reformed naphtha product and C6-C7 paraffins to C6-C7 aromatics.

BACKGROUND OF THE INVENTION

[0002] Catalytic reforming of naphtha is widely used in the petroleum refining industry to increase the octane number of naphtha for gasoline blending, generate H2, and generate chemical feedstocks. Important reactions that occur in catalytic reforming include the dehydrogenation of naphthenes to aromatics, isomerization of paraffins to isoparaffins, and the dehydrocyclization of paraffins to aromatics. Undesirable reactions include the hydrocracking of paraffins and naphthenes and the dealkylation of aromatics that results in the loss of liquid and hydrogen yields and the production of lower-valued fuel gas.

[0003] Typically, dual functional (or bifunctional) catalysts are employed for reforming processes. These dual functional catalysts include a metal function (e.g., Pt) as well as an acid function to dehydrogenate naphtha range paraffins and naphthenes, to catalyze ring closure of generated olefins and/or isomerization of olefins and paraffins. Many catalysts rely on chlorided alumina as the source of the acid functionality. However, the presence of chlorine and the need to continually supply chloride to the reactor to replenish chloride levels on the catalyst present many operational issues. For example, one issue caused by the presence of chlorine is the formation of chloramines by reaction of chloride with any nitrogen present in a naphtha feed stream to the reformer. The chloramines can facilitate chloride removal from the catalyst thereby increasing catalyst deactivation, system corrosion, and make-up chloride requirements. In order to avoid such a problem, a feed pretreater in the form of a naphtha hydrotreater is traditionally required to remove nitrogen from the system to an amount typically less than 1 ppm (preferably less than 0.5 ppm). Such constraints on the feed purity to a reformer can often result in the hydrotreater catalyst lifetime being determinative of reformer process turnaround time. Thus, there remains a need for catalysts for hydrocarbon conversion processes, such as reforming processes, which do not require chlorine and that can be used in the presence of nitrogen.

SUMMARY OF THE INVENTION

[0004] It has been unexpectedly found that a catalyst including a molecular sieve material, such as a zeolite, a silicoaluminophosphate (SAPO), and an aluminophosphate (A1PO), at least one transition metal and substantially no intentionally added chlorine can be used in the presence of nitrogen in systems and methods for converting hydrocarbons without significant loss of catalyst activity.

[0005] Thus, this disclosure relates to a method for converting hydrocarbons. A method can include contacting a hydrocarbon feed stream with a catalyst in the presence of greater than or equal to about 1 ppmw of nitrogen under effective conditions in a reaction zone to convert the hydrocarbon feed stream to a hydrocarbon product stream. The hydrocarbon feed stream may include a naphtha stream or a C6-C8 paraffin-containing stream including at least about 90 wt% C6-C8 paraffins based on total weight of the CT-Cs paraffin-containing stream. The hydrocarbon product stream may include a reformed naphtha stream or a G,-Cs aromatic-containing stream including at least about 90 wt% G,-Cs aromatics based on total weight of the G,-Cs aromatic- containing stream. The catalyst can include a mesoporous or microporous molecular sieve material selected from the group consisting of an aluminosilicate, a zeolite, a zeotype, an aluminosilicate, a silicoaluminophosphate (SAPO), an aluminophosphate (A1PO), and a combination thereof; at least one transition metal; and substantially no intentionally added chlorine.

[0006] In another aspect, this disclosure relates to a system for converting hydrocarbons. A system can include, a hydrocarbon feed stream, a hydrocarbon product stream, and at least one reactor operated under conditions to convert the hydrocarbon feed stream to the hydrocarbon product stream. The hydrocarbon feed stream may include a naphtha stream or a G,-Cs paraffin- containing stream including at least about 90 wt% G,-Cs paraffins based on total weight of the C6-C8 paraffin-containing stream. The hydrocarbon product stream may include a reformed naphtha stream or a G,-Cs aromatic-containing stream including at least about 90 wt% G,-Cs aromatics based on total weight of the G,-Cs aromatic-containing stream. The reactor may include a catalyst, nitrogen in an amount of greater than or equal to about 1 ppmw, a hydrocarbon feed inlet constructed and arranged to receive the hydrocarbon feed stream, and a hydrocarbon product outlet constructed and arranged to provide the hydrocarbon product stream. The catalyst may include a a mesoporous or microporous molecular sieve material selected from the group consisting of a zeolite, a zeotype, an aluminosilicate, a silicoaluminophosphate (SAPO), an aluminophosphate (A1PO), and a combination thereof, at least one transition metal, and substantially no intentionally added chlorine.

BRIEF DESCRIPTION OF THE FIGURES [0007] The drawings described herein are for illustrative purposes only of selected embodiments and not all possible implementations, and are not intended to limit the scope of the present disclosure.

[0008] FIG. 1A illustrates an exemplary embodiment of a system for converting hydrocarbons.

[0009] FIG. IB illustrates an exemplary embodiment of an alternative system for converting hydrocarbons.

[0010] FIG. 2 illustrates yield of toluene as a function of time on stream (TOS) at different concentrations of nitrogen (in ppm by weight N, provided as pyridine) for Catalysts A, B and C.

[0011] FIG. 3 illustrates yield of liquid petroleum gas (LPG) (C3 and C4 paraffins) as a function of TOS at different concentrations of nitrogen (in ppm by weight N, provided as pyridine) for Catalysts A, B and C.

[0012] FIG. 4 illustrates selectivity for LPG (C3 and C4 paraffins) as a function of TOS at different concentrations of nitrogen (in ppm by weight N, provided as pyridine) for Catalysts A, B and C.

[0013] FIG. 5 illustrates selectivity for toluene as a function of (C3 and C4 paraffins) as a function of TOS at different concentrations of nitrogen (in ppm by weight N, provided as pyridine) for Catalysts A, B and C.

[0014] FIG. 6 illustrates yield of C1+C6 and C2+C5 metal catalyzed cracking products as a function of TOS at different concentrations of nitrogen (in ppm by weight N, provided as pyridine) for Catalysts A, B and C.

DETAILED DESCRIPTION

DEFINITIONS

[0015] To facilitate an understanding of the present invention, a number of terms and phrases are defined below.

[0016] For purposes of this disclosure and the claims hereto, the numbering scheme for the Periodic Table Groups is according to the IUPAC Periodic Table of Elements.

[0017] As used in the present disclosure and claims, the singular forms“a,”“an,” and“the” include plural forms unless the context clearly dictates otherwise.

[0018] The term“and/or” as used in a phrase such as“A and/or B” herein is intended to include“A and B”,“A or B”,“A”, and“B”.

[0019] As used herein, and unless otherwise specified, the term“Cn” means hydrocarbon(s) having n carbon atom(s) per molecule, wherein n is a positive integer.

[0020] As used herein, and unless otherwise specified, the term“hydrocarbon” means a class of compounds containing hydrogen bound to carbon, and encompasses (i) saturated hydrocarbon compounds, (ii) unsaturated hydrocarbon compounds, and (iii) mixtures of hydrocarbon compounds (saturated and/or unsaturated), including mixtures of hydrocarbon compounds having different values of n.

[0021] As used herein, and unless otherwise specified, the term “aromatic” refers to unsaturated cyclic hydrocarbons having a delocalized conjugated p system and having from 5 to 30 carbon atoms (aromatic C5-C30 hydrocarbon). Exemplary aromatics include, but are not limited to benzene, toluene, xylenes, mesitylene, ethylbenzenes, cumene, naphthalene, methylnaphthalene, dimethylnaphthalenes, ethylnaphthalenes, acenaphthalene, anthracene, phenanthrene, tetraphene, naphthacene, benzanthracenes, fluoranthrene, pyrene, chrysene, triphenylene, and the like, and combinations thereof. Additionally, the aromatic may comprise one or more heteroatoms. Examples of heteroatoms include, but are not limited to, nitrogen, oxygen, and/or sulfur. Aromatics with one or more heteroatom include, but are not limited to furan, benzofuran, thiophene, benzothiophene, oxazole, thiazole and the like, and combinations thereof. The aromatic may comprise monocyclic, bi cyclic, tricyclic, and/or polycyclic rings (in any embodiment, at least monocyclic rings, only monocyclic and bicyclic rings, or only monocyclic rings) and may be fused rings.

[0022] As used herein, the term“olefin,” alternatively referred to as“alkene,” refers to an unsaturated hydrocarbon chain of 2 to about 12 carbon atoms in length containing at least one carbon-to-carbon double bond. The olefin may be straight-chain or branched-chain. Non- limiting examples include ethylene, propylene, butylene, and pentene.“Olefin” is intended to embrace all structural isomeric forms of olefins. As used herein, the term“light olefin” refers to olefins having 2 to 4 carbon atoms (i.e., ethylene, propylene, and butenes).

[0023] As used herein, and unless otherwise specified, the term“paraffin,” alternatively referred to as“alkane,” refers to a saturated hydrocarbon chain of 1 to about 30 carbon atoms in length, such as, but not limited to methane, ethane, propane and butane. The paraffin may be straight-chain, cyclic or branched-chain.“Paraffin” is intended to embrace all structural isomeric forms of paraffins. The term“acyclic paraffin” refers to straight-chain or branched-chain paraffins. The term“isoparaffin” refer to branched-chain paraffin, and the term“n-paraffin” or “normal paraffin” refers to straight-chain paraffins.

[0024] As used herein, and unless otherwise specified, the term“naphthene” refers to a cycloalkane (also known as a cycloparaffin) having from 3-30 carbon atoms. Examples of naphthenes include, but are not limited to cyclopropane, cyclobutane, cyclopentane, cyclohexane, cycloheptane, cyclooctane and the like. The term naphthene encompasses single- ring naphthenes and multi-ring naphthenes. The multi-ring naphthenes may have two or more rings, e.g., two-rings, three-rings, four-rings, five-rings, six-rings, seven-rings, eight-rings, nine- rings, and ten-rings. The rings may be fused and/or bridged. The naphthene can also include various side chains, particularly one or more alkyl side chains of 1-10 carbons.

[0025] As used herein, the term“naphtha” or“naphtha boiling range” refers to a middle boiling range hydrocarbon fraction or fractions, typically including three or more hydrocarbons (e.g., between four and twelve carbon atoms), which are major components of gasoline, and having a boiling range distribution of about 10°C to about 232°C. Naphtha and naphtha holing range components can include paraffins, olefins, naphthenes and/or aromatics. In one embodiment, naphtha or naphtha boiling range components is further defined to have a boiling range distribution of about 38°C to about 200°C at 0.101 MPa as measured according to ASTM D86, and further defined to meet ASTM standard D4814.

[0026] As used herein, "reaction zone" refers to any vessel(s) in which a chemical reaction occurs, for example, a batch reactor or continuous reactor. When multiple reactors are used in either series or parallel configuration, each reactor may be considered as a separate reaction zone. Alternatively, a reactor may include one or more reaction zones.

[0027] As used herein, the term“straight run naphtha” refers to petroleum naphtha obtained directly from fractional distillation.

[0028] As used herein, the term“fluid catalytic cracker (FCC) naphtha” refers to naphtha produced by the well-known process of fluid catalytic cracking. The term FCC naphtha is intended to encompass one or more of light cut naphtha (LCN), intermediate cut naphtha (ICN), and heavy cut naphtha (HCN).

[0029] As used herein, the term“coker naphtha” refers to naphtha produced by the well- known process of coking in one or more coker units or cokers. Coker naphtha generally includes more sulfur and/or nitrogen than straight run naphtha.

[0030] As used herein, the term“delayed coker naphtha” refers to naphtha produced by the well-known process of delayed coking.

[0031] As used herein, the term“fluid coker naphtha” refers to naphtha produced by the well-known process of fluid coking.

[0032] As ushed herein, the term“hydrocrackate” refers to a naphtha cut of a hydrocracker byproduct.

[0033] As used herein, the term“hydrotreated naphtha” refers to naphtha produced by the well-known process of hydrotreating. [0034] As used herein, the term“steam cracker naphtha (SCN)” refers to naphtha produced by the well-known process of steam cracking.

[0035] A common method for characterizing the octane rating of a composition is to use an average of the Research Octane Number (RON). Although various methods are available for determining RON, in the claims below, references to Research Octane Number (RON) correspond to RON determined as described in Ghosh, P. et al. (2006)“Development of Detailed Gasoline Composition-Based Octane Model,” Ind. Eng. Chem. Res., 45 1), pp 337-345.

[0036] As used herein, the term“molecular sieve” refers to crystalline or non-crystalline materials having a porous structure. A molecular sieve may be microporous and typically have pores having a diameter of less than or equal to about 2.0 nm. Additionally or alternatively, a molecular sieve may be mesoporous and typically have pores with diameters of about 2 to about 50 nm.

METHODS OF CONVERTING HYDROCARBONS

[0037] Methods for converting hydrocarbons are provided herein. The methods comprise contacting a hydrocarbon feed stream with a catalyst in a reaction zone under effective conditions in a reaction zone to convert the hydrocarbon feed stream to a hydrocarbon product stream. In any embodiment, the catalyst comprises a molecular sieve, at least one transition metal, and substantially no added chlorine. Advantageously, using a catalyst as described herein with substantially no intentionally added chlorine can relax constraints on nitrogen provided to the reaction zone, such that the methods described herein can be performed in the presence of nitrogen without significant loss of catalyst activity. Consequently, the methods described herein can improve operation performance. For example, during naphtha reforming processes, operation can be improved by debottlenecking a feed hydrotreater and potentially allowing for greater catalyst lifetime of the hydrotreating catalyst, which can extend the time between process turnarounds.

Hydrocarbon Feed Stream

[0038] In any embodiment, the hydrocarbon feed stream may comprise, consist essentially of, or consist of a naphtha stream, for example, having a boiling range of about 10°C to about 232°C. The naphtha stream may comprise one or more of the following: hydrotreated naphtha, fluid catalytic cracker (FCC) naphtha, straight run naphtha, coker naphtha, delayed coker naphtha, steam cracker naphtha (SCN), fluid coker naphtha, and hydrocrackate. In any embodiment, the hydrocarbon feed stream may comprise FCC naphtha, straight run naphtha hydrotreated naphtha, coker naphtha, or a combination thereof. In any embodiment, the hydrocarbon feed stream is FCC naphtha comprising one or more of of light cut naphtha (LCN), intermediate cut naphtha (ICN), and heavy cut naphtha (HCN).

[0039] In any embodiment, the hydrocarbon feed stream may comprise naphtha in an amount of (based on total weigh of hydrocarbon feed stream) at least about 50 wt%, at least about 70 wt%, at least about 90 wt%, at least about 95 wt%, at least about 99 wt% or about 100 wt%; or in a range of about 50-100 wt%, about 70-100 wt% or about 90-100 wt%.

[0040] The naphtha stream may have various properties. For example, the naphtha stream may have a lower octane rating. In any embodiment, the naphtha stream may have an octane rating (RON) less than or equal to about 80, less than or equal to about 70, less than or equal to about 60, less than or equal to about 50, less than or equal to about 40, or about 30; or in a range of about 30-80, about 40-70 or about 50-60.

[0041] In any embodiment, the naphtha stream may have an American Petroleum Institute (API) gravity, as measured according to ASTM D4052, of at least about 30, at least about 45, at least about 50, at least about 55, at least about 60, at least about 65 or about 70; or in a range of about 45-70, about 50-70 or about 55-65. Bromine number, representative of olefin content, of the naphtha stream may be typically from about about 0-80, about 45-80, about 50-75, about 50-70, unless lowered by a significant amount of straight run naphtha. Bromine number may be measured according to ASTM D1159.

[0042] Additionally or alternatively, the naphtha stream may have a sulfur content, as measured according to ASTM D4294, of at least about 10 ppmw, at least about 50 ppmw, at least about 100 ppmw, at least about 250 ppmw, at least about 500 ppmw, at least about 750 ppmw, or about 1000 ppmw; or in a range of about 10-1000 ppmw, about 50-1000 ppmw, about 100-900 ppmw, about 500-800 ppmw, or about 10-50 ppmw. In any embodiment, the naphtha stream may have been or may not have been subjected to hydrotreating before entering the reaction zone. In any embodiment, a naptha stream which, for example, has been subjected to hydrotreating may have a sulfur content of less than or equal to about 5 ppmw, less than or equal to about 1 ppmw, less than or equal to about 0.5 ppmw, or about 0.1 ppmw; or in a range of about 0.1 ppmw to about 5 ppmw, about 0.1 ppmw to about 1 ppmw, or about 0.1 ppmw to about 0.5 ppmw.

[0043] Alternatively, the hydrocarbon feed stream may comprise, consist essentially of, or consist of a G,-G paraffin-containing stream, for example, heptane, hexane and/or octane. In any embodiment, the hydrocarbon feed stream may comprise, consist essentially of, or consist of a C6-C8 paraffin-containing stream. In any embodiment when the hydrocarbon feed stream may be a C6-C8 paraffin-containing stream, the G,-Cs paraffin-containing stream may comprise G,-Cs paraffins (based on total weight of the C6-C8 paraffin-containing stream), singularly or in combination, in an amount of at least about 70 wt%, at least about 80 wt%, at least about 90 wt%, at least about 95 wt%, at least about 99 wt% or about 100 wt%; or in a range of about 70- 100 wt%, about 90-100 wt% or about 95-100 wt%. In any embodiment, the C6-C8 paraffin- containing stream may comprise a majority (e.g., greater than 50 wt%, greater than 75 wt%, greater than 90 wt%, etc.) heptane or may comprise all heptane (e.g., greater than 99 wt% or about 100 wt%). Alternatively, in any embodiment, the G,-Cs paraffin-containing stream may comprise a majority (e.g., greater than 50 wt%, greater than 75 wt%, greater than 90 wt%, etc.) hexane or may comprise substantially all hexane (e.g., greater than 99 wt% or about 100 wt%). Alternatively, in any embodiment, the G,-Cs paraffin-containing stream may comprise a majority (e.g., greater than 50 wt%, greater than 75 wt%, greater than 90 wt%, etc.) octane or may comprise substantially all octane (e.g., greater than 99 wt% or about 100 wt%).

[0044] In any embodiment, a G,-Cs paraffin-containing stream may have a sulfur content of less than or equal to about 5 ppmw, less than or equal to about 1 ppmw, less than or equal to about 0.5 ppmw, or about 0.1 ppmw; or in a range of about 0.1 ppmw to about 5 ppmw, about 0.1 ppmw to about 1 ppmw, or about 0.1 ppmw to about 0.5 ppmw.

Nitrogen

[0045] As discussed above, the methods described herein advantageously may be performed in the presence of nitrogen. Furthermore, it was discovered that the presence of nitrogen can block excess acid sites on the catalyst (further described below) thereby reducing unselective and undesirable side reactions, such as unselective cracking, and consequently reducing liquid yield loss. As used herein “nitrogen” encompasses nitrogen (N) present in nitrogen-containing compounds, such as, but not limited to amines and alkylamines (e.g. tertiary butylamine), ammonia, nitrogen-containing heterocyclic compounds (e.g., pyridine, pyrrole), as well as N2.

[0046] In any embodiment, nitrogen may be present in amount of greater than or equal to about 1 ppmw, greater than or equal to about 10 ppmw, greater than or equal to about 100 ppmw, greater than or equal to about 1,000 ppmw, greater than or equal to about 5,000 ppmw, or about 10,000 ppmw; or in a range of about 1-10,000 ppmw, about 1-5,000 ppmw, about 1-100 ppmw, about 10-10,000 ppmw, about 10-1,000 ppmw, or about 10-100 ppmw. When referring to the above-described amounts of nitrogen (N), the amount is based on the amount of nitrogen (N) or basic nitrogen, not N2.

[0047] The nitrogen may be provided to the reaction zone in various ways. For example, the nitrogen may be present in the hydrocarbon feed stream, the nitrogen may be provided via a separate nitrogen stream, or a combination thereof. In any embodiment, a separate nitrogen stream may be mixed with the hydrocarbon feed stream prior to the hydrocarbon feed stream entering the reaction zone. Additionally or alternatively, a separate nitrogen stream may be provided directly to the reaction zone. In any embodiment, a separate nitrogen stream may be provided to one or more reaction zones at any time during the conversion reaction. For example, a separate nitrogen stream may be provided to a reaction zone at the beginning of the conversion reaction, for example, substantially concurrently with the hydrocarbon feed stream, or a separate nitrogen stream may be provided to a reaction zone at some point in later in time (after the beginning) during the conversion reaction. Alternatively, if multiple reaction zones (e.g., a first reaction, a second reaction zone, a third reaction zone, etc.) are present, a separate nitrogen stream may be provided to the second reaction and/or the third reaction zone. In any embodiment, nitrogen may be present in the hydrocarbon stream, for example, as an impurity, in a lower amount (e.g., less than about 10 ppmw, or less than about 1 ppmw) and additional nitrogen may be provided via a separate nitrogen stream having a higher content of nitrogen (e.g., greater than 10 ppmw, greater than 25 ppmw, etc.), which may be mixed with a hydrocarbon feed stream, provided separately to the reaction zone or a combination thereof. Alternatively, in any embodiment, nitrogen may be provided to the reaction zone only via a separate nitrogen stream.

Catalyst

[0048] The catalysts for use in the methods and systems described herein may include a molecular sieve material, at least one transition metal, and substantially no intentionally added chlorine. As used herein“intentionally added” refers to chlorine or chloride added to a catalyst, for example, added to the molecular sieve and/or binder via chlorine-containing compounds, for purposes of providing a source of acid functionality to the catalyst and/or contributing positively to the performance of the catalyst. For example, chlorided alumina has been intentionally added to catalysts as a source of acid functionality. Thus,“no intentionally added” excludes the addition of chloride alumina and the like from the catalyst compositions described herein. “Intentionally added” does not include chlorine or chloride present in the catalyst compositions as an impurity, for example, where chlorine-containing compounds, such as structure directing agents, are used to prepare the molecular sieve or chlorine-containing and metal-containing precursors are used to add the metals (e.g., Pt) to the molecular sieve, and the resultant molecular sieve contains a trace amount of chlorine. As used herein,“substantially no intentionally added chlorine” means any intentionally added chlorine, if present, is present in a minor, or a non- substantial, or a negligible amount, or not present at all (for example, such component is present in an amount less than 1.0 wt%, less than 0.10 wt%, less than 0.010 wt%, or 0.0 wt% based on the weight of the catalyst).

[0049] The molecular sieve materials useful herein include mesoporous or microporous materials. As used herein, and unless otherwise specified, the term "mesoporous" refers to solid materials having pores that have a diameter within the range of from about 2 nm to about 50 nm. As used herein, and unless otherwise specified, the term "microporous" refers to solid materials having pores that have a diameter of less than 2 nm. Non-limiting examples of suitable molecular sieve materials include a zeolite, an aluminosilicate, a silicoaluminophosphate (SAPO), an aluminophosphate (A1PO), a zeotype, and combinations thereof. As used herein, “zeolite” is defined to refer to a crystalline material having a porous framework structure built from tetrahedra atoms connected by bridging oxygen atoms. Examples of known zeolite frameworks are given in the“Atlas of Zeolite Frameworks” published on behalf of the Structure Commission of the International Zeolite Association”, 6 ^th revised edition, Ch. Baerlocher, L.B. McCusker, D.H. Olson, eds., Elsevier, New York (2007) and the corresponding web site, http://www.iza-structure.org/databases/. Under this definition, a zeolite can refer to aluminosilicates having a zeolitic framework type as well as crystalline structures containing oxides of heteroatoms different from silicon and aluminum. Such heteroatoms can include any heteroatom generally known to be suitable for inclusion in a zeolitic framework, such as gallium, boron, germanium, phosphorus, zinc, antimony, tin, and/or other transition metals that can substitute for silicon and/or aluminum in a zeolitic framework. As used herein, “zeotype” refers to any members of a family of artificial materials winch are based on the structure of zeolites. Under this definition, zeotype can include heteroatoms generally known to be suitable for inclusion in a zeolitic framework, such as gallium, boron, germanium, phosphorus, zinc, antimony, tin, and/or other transition metals that can substitute for silicon and/or aluminum in a zeolitic framework

[0050] In any embodiment, suitable zeolites include zeolites comprising a ten-membered ring, a twelve-membered ring, or a combination thereof. Preferably, the zeolite comprises a ten- membered ring, a twelve-membered ring, or a combination thereof. Nonlimiting examples of zeolite framework structures having ten-membered rings include AEL, AFO, AHT, CFG, CGS, DAC, EUO, FER, HEU, IMF, ITH, LAU, MEL, MFI, MFS, MTTK, MWW, NES, OBW, -PAR, PON, RRO, SFF, SFG, STF, STI, SZR, TER, TON, TUN, WEI, and -WEN. Nonlimiting examples of zeolite framework structures having twelve-membered rings include AFI, AFR, AFS, AFY, ASV, ATO, BEA, BEC, BOG, BPH, CAN CON, CZP, DFO, EMT, EON, EZT, FAU, GME, GON, IFR, ISV, IWR, IWV, IWW, LTL, MAZ, MEI, MOR, MOZ, MSE, MTW, NOP, OFF, OSI, -RON, RWY, SAO, SBE, SBS, SBT, SFE, SFO, SOS, SSY, USI, VET, and intermediates thereof.

[0051] In any embodiment, the zeolite has a framework structure selected from the group consisting of FAU, LTL, BEA, MAZ, MTW, MEI MOR, and EMT-FAU intermediates. Examples of zeolites having an FAU framework structure include, but are not limited to US-Y (or dehydrated US-Y), Na-X (or dehydrated Na-X), LZ-210, Li-LSX, zeolite X, and zeolite Y. Examples of zeolites having a LTL framework structure include, but are not limited to zeolite L, gallosillicate L, LZ-212 and perlialite. Examples of zeolites having a BEA framework structure include, but are not limited to beta, Al-rich beta, CIT-6, and pure silica beta. Examples of zeolites having an MAZ framework structure include, but are not limited to mazzite, LZ-202, and ZSM-4. Examples of zeolites having an MTW framework structure include, but are not limited to ZSM-12, CZH-5, NU-13, TPZ-12, Theta-3 and VS-12. Examples of zeolites having an MEI framework structure include, but are not limited to ZSM-18 and ECR-40. Examples of zeolites having an MOR framework structure include, but are not limited to Ca-Q, LZ-211, mordenite, and Na-D. Examples of zeolites having an EMT-FAU intermediate structure include, but are not limited to CSZ-1, ECR-30, ECR-32, ZSM-20 and ZSM-3. In any embodiment, the zeolite is selected from the group consisting of zeolite L, zeolite Y, and US-Y.

[0052] Additionally or alternatively, the molecular sieve material may be an aluminophosphate (i.e.. A1PO). Suitable AlPOs can include, but are not limited to AlPO-11, A1PO-H2, A1PO-31 and A1PO-41.

[0053] Additionally or alternatively, the molecular sieve material may be a silicoaluminophosphate (i.e.. SAPO). Suitable SAPOs can include, but are not necessarily limited to SAPO-11, SAPO-37, SAPO-41, and SAPO-31.

[0054] Additionally or alternatively, the molecular sieve material may be an aluminosilicate, such as, but not limited to MCM-41.

[0055] A person of ordinary skill in the art knows how to make the aforementioned frameworks and molecular sieve materials. For example, see the references provided in the International Zeolite Association’s database of zeolite structures found at www.iza- structure. org/ databases

[0056] In any embodiment, the molecular sieve material may have hexane cracking activity as described by US. Patent No. 3,354,078, of less or equal to about 100, less than or equal to about 50, less than or equal to about 25, less than or equal to about 10, less than or equal to about 5 or about 1; or in a range of about 1-100, about 1-25, about 1-10 or about 15.

[0057] In any embodiment, the molecular sieve material, for example, the zeolite may have a bulk silica to alumina ratio of at least about 5: 1, at least about 25: 1, at least about 50: 1, at least about 100: 1, at least about 200: 1, or at least about 400: 1. As used herein,“bulk silica to alumina ratio” refers to a silica to alumina ratio of the molecular sieve material inclusive of alumina within and outside the framework (extra-framework alumina). In any embodiment, the molecular sieve material, for example, the zeolite may have a framework silica to alumina ratio of at least about 10: 1, at least about 50: 1, at least about 100: 1, at least about 250: 1, at least about 500: 1, or at least about 1000: 1. As used herein,“framework silica to alumina ratio” refers to a silica to alumina ratio of the molecular sieve material of only alumina within the framework and exclusive of alumina outside the framework (extra-framework alumina). The bulk silica to alumina ratio and framework silica to alumina ratio are measured post-modification, for example, after steaming, silicone selectivation and/or acid/base leaching of the molecular sieve material.

[0058] One or more transition metals may be present in the catalyst. For example, a transition metal may be present, based on total weight of the catalyst, in an amount of at least about 0.01 wt%, at least about 0.05 wt%, at least about 1 wt%, at least about 2.5 wt%, at least about 5 wt%, or about 7.5 wt%; or in a range from about 0.01-7.5 wt%, about 0.05-7.5 wt%, about 0.05-5 wt%, about 0.05-2.5 wt% or about 0.05-1 wt%. In any embodiment, the transition metal may be a Group 10 transition metal, for example, nickel (Ni), palladium (Pd), or platinum (Pt). In any embodiment, the transition metal may be Pt.

[0059] Additionally or alternatively, a base metal or a non-precious metal may be present in the catalyst. For example, a base metal may be present, based on total weight of the catalyst, in an amount of at least about at least about 1 wt%, at least about 10 wt%, at least about 20 wt% or about 40 wt%; or in a range from about 1-40 wt%, about 10-40 wt%, or about 20-40 wt%. Examples of base metals include, but are not limited to lead (Pb), nickel (Ni), zinc (Zn) or copper (Cu).

[0060] Additionally or alternatively, one or more promoter metals may be present in the catalyst. For example, a promoter metal may be present, based on total weight of the catalyst, in an amount of at least about 0.005 wt%, at least about 0.01 wt%, at least about 0.5 wt%, at least about 1 wt%, at least about 10 wt% or about 15 wt%; or in a range from about 0.005-15 wt%, about 0.005-10 wt%, about 0.005-7.5 wt%, about 0.005-1 wt% or about 0.01-1 wt%. In any embodiment, the promoter metal may be a Group 7 metal, a Group 9 metal, a Group 11 metal, a Group 13 metal and a Group 14 metal. Examples of promoter metals include, but are not limited to rhenium (Re), tin (Sn), gallium (Ga), indium (In), iridium (Ir), germanium (Ge), rhodium (Rh), ruthenium (Ru), and copper (Cu).

[0061] Additionally or alternatively, one or more alkali metals may be present in the catalyst. For example, an alkali metal may be present, based on total weight of the catalyst, in an amount of at least about 0.005 wt%, at least about 0.01 wt%, at least about 0.5 wt%, at least about 1 wt%, at least about 5 wt%, or at least about 10 wt%; or in a range from about 0.005-10 wt%, about 0.005-5 wt%, about 0.01-1 wt% or about 0.5-1 wt%. In any embodiment, the alkali metal may be lithium (Li), sodium (Na), potassium (K), rubidium (Rb) or cesium (Ce).

[0062] Additionally or alternatively, one or more alkaline earth metals may be present in the catalyst. For example, an alkaline metal may be present, based on total weight of the catalyst, in an amount of at least about 0.005 wt%, at least about 0.01 wt%, at least about 0.5 wt%, at least about 1 wt%, at least about 5 wt%, or at least about 10 wt%; or in a range from about 0.005-10 wt%, about 0.005-5 wt%, about 0.01-1 wt% or about 0.5-1 wt%. In any embodiment, the alkaline earth metal may be beryllium (Be), magnesium (Mg), calcium (Ca), strontium (Sr) or barium (Ba).

[0063] Additionally or alternatively, the zeolite may be present at least partly in hydrogen form in the catalyst. Depending on the conditions used to synthesize the zeolite, this may implicate converting the zeolite from, for example, the alkali (e.g., sodium) form. This can readily be achieved, e.g., by ion exchange to convert the zeolite to the ammonium form, followed by calcination in air or an inert atmosphere at a temperature from about 400°C to about 1000°C to convert the ammonium form to the active hydrogen form. If an organic structure directing agent is used in the synthesis of the zeolite, additional calcination may be desirable to remove the organic structure directing agent.

[0064] The catalysts described herein can optionally be employed in combination with a support or binder material (binder). It is contemplated herein that the metals described above may be supported on the molecular sieve material, on the binder, or a combination thereof. Typical methods for incorporation of a metal on a molecular sieve and/or binder include impregnation (such as by incipient wetness), ion exchange, deposition by precipitation, and any other convenient method for depositing a metal on a molecular sieve and/or binder.

[0065] Binders may be catalytically active or inactive and include other zeolites, other inorganic materials such as clays and metal oxides such as alumina, silica, silica-alumina, titania, zirconia, Group 1 metal oxides, Group 2 metal oxides, and combinations thereof. Clays may be kaolin, bentonite and montmorillonite and are commercially available. They may be blended with other materials such as silicates. Other binary porous matrix materials in addition to silica- aluminas include materials such as silica-magnesia, silica-thoria, silica-zirconia, silica-beryllia and silica-titania. Ternary materials such as silica-alumina-magnesia, silica-alumina-thoria and silica-alumina-zirconia can also be suitable for use as binders. One or more binders may be used, for example, silica and alumina may be used in combination. [0066] A binder may be present in the catalyst in an amount, based on total weight of the catalyst, of at least about 1 wt%, at least about 25 wt%, at least about 50 wt%, at least about 75 wt%, at least about 90 wt%, at least about 95 wt%, or about 99 wt%; or in a range of about 1-99 wt%, about 1-95 wt%, about 25-95 wt% or about 50-90 wt%. In any embodiment, molecular sieve material to binder ratio may be about 10: 1, about 2: 1, about 1: 1, about 1 :2, about 1:4, or about 1 : 10.

[0067] In any embodiment, the catalyst can be steamed under effective steaming conditions. For example, the molecular sieve material may be steamed to further reduce acidity prior to metal incorporation. In any embodiment, the catalyst may be steamed once or multiple times. General examples of effective steaming conditions (carried out once or multiple times) include exposing a catalyst to an atmosphere comprising steam at a temperature of about 400°C to about 1200°C, about 400°C to about 850°C, about 400°C to about 650°C, about 500°C to about 850°C, about 500°C to about 750°C, or about 500°C to about 650°C. The atmosphere can include as little as 1 vol% water and up to 100 vol% water. The catalyst can be exposed to the steam for any convenient period of time, such as about 10 minutes (0.15 hours) to about 48 hours. In any embodiment, if steamed multiple times, the steamings can occur with other steps performed in between steamins, for example, acid leaching. In any embodiment, steaming may occur to the zeolite particle before binding and/or to a formulated extrudate.

[0068] In any embodiment, the catalyst may undergo silicone seletivation. Silicone selectivation can be performed with any suitable silicone oil (e.g. Dow Coming 550) or from an organic silica source such as tetraethyl orthosilicate (TEOS).

[0069] In any embodiment, catalyst may undergo acid leaching. Typical leaching conditions can include using a suitable acid, such oxalic acid, citric acid, or nitric acid, in concentrations ranging from about 0.1 up to about 10 molar, preferably about 1 molar, at a temperature ranging from about 20°C up to about 100°C.

[0070] In any embodiment, the catalyst may be sulfided prior to use to form a sulfided catalyst. The sulfidation of the metals can be performed by any convenient method, such as gas phase sulfidation or liquid phase sulfidation. Sulfidation is generally carried out by contacting a catalyst precursor (such as a catalyst precursor that includes metals complexed by a dispersion agent and/or metals in the form of metal oxides) with a sulfur containing compound, such as elemental sulfur, hydrogen sulfide or polysulfides. Hydrogen sulfide is a convenient sulfidation agent for gas phase sulfidation, and can be incorporated into a gas phase sulfidation atmosphere containing hydrogen in an amount of about 0.1 wt% to 10 wt%. Sulfidation can also be carried out in the liquid phase utilizing a combination of a polysulfide, such as a dimethyl disulfide spiked hydrocarbon stream, and hydrogen. The sulfidation can be performed at a convenient sulfidation temperature, such as a temperature from 150°C to 500°C. The sulfidation can be performed at a convenient sulfidation pressure, such as a pressure of 100 psig to 1000 psig or more. The sulfidation time can vary depending on the sulfidation conditions, so that sulfidation times of 1 hour to 72 hours can be suitable.

Reaction Conditions

[0071] It is contemplated herein that the methods described may be performed in one or more reaction zones. For example, when upgrading a naphtha stream, the processes of isomerization, cracking, dehydrogenation, and dehydrocyclization can be performed in one or more reaction zones.

[0072] Additionally, the methods described herein may further comprise providing hydrogen (Fk) to the reaction zone. The reaction conditions for converting the hydrocarbon feed stream to the hydrocarbon product stream may be any suitable conditions known in the art, for example, for upgrading a naphtha stream or converting C6-C7 paraffins to C6-C7 aromatics. For example, the methods may be performed at a temperature of about 400°C to about 750°C, a pressure of about 100 kPa to about 10000 kPa, weight hourly space velocity (WHSV) of about 0.1 to about 10 and an Fkihydrocarbon ratio of about 0.1 to about 10. However, it is contemplated herein that the reaction conditions may vary based on the properties of the hydrocarbon feed stream, feed configurations, and/or the reactor configuration. For example, the reaction zone may comprise a fixed bed reactor and moving bed reactor. A fixed bed reactor may operate at higher pressures compared to a moving bed reactor.

[0073] In any embodiment, the methods described herein advantageously may be operated at higher conditions, e.g. , temperature, pressure, to produce a higher yield because the catalysts described herein are more stable with time on stream, for example, when compared to traditional catalysts containing intentionally added chlorine. Regeneration of the catalyst can occur as frequently as every 1 to 3 days or as infrequently as 3 to 12 months depending the hydrocarbon feed stream and the reaction conditions.

Hydrocarbon Product Stream

[0074] In any embodiment, the hydrocarbon product stream may comprise, consist essentially of, or consist of an upgraded naphtha stream or reformed naphtha stream when the hydrocarbon feed stream is a naphtha stream. The upgraded naphtha stream or reformed naptha stream may have a higher octane rating than the naphtha stream provided to the reaction zone. For example, the upgraded naphtha stream or reformed naptha stream may have an octane rating (RON) of at least about 80, at least about 85, at least about 90, at least about 95, at least about 98, or about 100; or in a range of about 80-100, about 90-100 or about 95-100. In any embodiment, the upgrade naphtha stream or reformed naptha stream may be used as a blendstock and be further blended with other streams, such as a gasoline source.

[0075] Alternatively, in any embodiment, the hydrocarbon product stream may comprise, consist essentially of, or consist of a G-G aromatic-containing stream. In any embodiment when the hydrocarbon product stream may be a G-G aromatic-containing stream, the G-G aromatic-containing stream may comprise G-G aromatic (based on total weight of the G-G aromatic-containing stream), singularly or in combination, in an amount of at least about 30 wt%, at least about 50 wt%, at least about 70 wt%, at least about 90 wt%, at least about 99 wt% or about 100 wt%; or in a range of about 30-100 wt%, about 50-100 wt%, about 70-100 wt%, about 30-90 wt% or about 50-70 wt%. In any embodiment, the G-G aromatic-containing stream may comprise a majority (e.g., greater than 50 wt%, greater than 75 wt%, greater than 90 wt%, etc.) benzene or may comprise all benzene (e.g., greater than 99 wt% or about 100 wt%). Alternatively, in any embodiment, the G-G aromatic-containing stream may comprise a majority (e.g., greater than 50 wt%, greater than 75 wt%, greater than 90 wt%, etc.) toluene or may comprise substantially all toluene (e.g., greater than 99 wt% or about 100 wt%). Alternatively, in any embodiment, the G-G aromatic-containing stream may comprise a majority (e.g., greater than 50 wt%, greater than 75 wt%, greater than 90 wt%, etc.) G aromatic (e.g., ethylbenzene, p-xylene, and/or m-xylene) or may comprise substantially all G aromatic (e.g., greater than 99 wt% or about 100 wt%). In any embodiment, the C6-C8 aromatic- containing stream, for example, the balance of the G-G aromatic-containing stream not comprising C6-C8 aromatics, may comprise unconverted G-G paraffins, e.g., hexane, heptane, and/or octane, or side reaction products.

III. SYSTEMS FOR CONVERTING HYDROCARBONS

[0076] Systems for converting hydrocarbons utilizing the catalysts described herein are also provided. An exemplary system 1 is provided in FIG. 1A. The system 1 includes a hydrocarbon feed stream 2, at least one reactor 3 and a hydrocarbon product stream 4. In any embodiment, the hydrocarbon feed stream 2 may be a naphtha feed stream as described herein, for example, a hydrotreated naphtha, fluid catalytic cracker (FCC) naphtha, straight run naphtha, coker naphtha, delayed coker naphtha, fluid coker naphtha or a combination thereof. In any embodiment, the hydrocarbon feed stream 2, which is a naphtha feed stream, may have a boiling range of about 10°C to about 232°C and/or an octane rating (RON) of about 40-70. It is contemplated herein that depending on refinery conditions and configuration, the naphtha feed stream may have an octane rating (RON) outside the range of about 40-70. When the hydrocarbon feed stream 2 is a naphtha stream, the hydrocarbon product stream 4 may be a reformed naphtha stream as described herein, for example, having an octane rating as determined by (RON+MON)/2, of at least about 90.

[0077] Alternatively, in any embodiment, the hydrocarbon feed stream 2 may be a C6-C7 paraffin-containing stream as described herein, for example, comprising C6-C7 paraffins (based on total weight of the C6-C7 paraffin-containing stream), singularly or in combination, in an amount of at least about 90 wt%. When the hydrocarbon feed stream 2 is a C6-C7 paraffin- containing stream, the hydrocarbon product stream 4 may be a C6-C7 aromatic-containing stream as described herein, for example, comprising C6-C7 aromatics (based on total weight of the C6-C7 aromatic-containing stream), singularly or in combination, in an amount of at least about 90 wt%.

[0078] The reactor 3 may be any suitable reactor, such as a moving bed reactor or a fixed bed reactor. In any embodiment, the reactor 3 may encompass a series of reactors, for example a series of reactor beds arranged horizontally or stacked vertically (e.g., moving bed reactors), which may have reheating zones in between them. The reactor 3 may be operated under conditions as described herein to convert the hydrocarbon feed stream 2 to the hydrocarbon product stream 4. In any embodiment, the conditions may comprise one or more of a temperature of about 400°C to about 750°C, a pressure of about 100 kPa to about 10000 kPa, weight hourly space velocity (WHSV) of about 0.1 to about 10 and an Fkihydrocarbon ratio of about 0.1 to about 10. The reactor 3 may comprise a catalyst as described herein for contacting with the hydrocarbon feed stream 2 and nitrogen in an amount as described herein, for example, greater than or equal to about 1.0 ppmw or from about 10-1000 ppmw. The reactor 3 may also include a hydrocarbon feed inlet (not shown) constructed and arranged to receive the hydrocarbon feed stream 2, and a hydrocarbon product outlet (not shown) constructed and arranged to provide the hydrocarbon product stream 4.

[0079] The nitrogen may be provided to the reactor 3 as described herein. For example, the nitrogen may be present in the hydrocarbon feed stream 2. In any embodiment, the hydrocarbon feed stream 2 may provide a sufficient amount of nitrogen and no further nitrogen addition may be needed. Additionally or alternatively, nitrogen optionally may be provided via a separate nitrogen stream. A separate nitrogen stream may be provided to the reactor any time during the conversion reaction. For example, as shown in FIG. IB, nitrogen optionally may be provided to the hydrocarbon feed stream 2 via a feed nitrogen stream 5 before the hydrocarbon feed stream 2 enters the reactor 3 in a system 10. Additionally or alternatively, nitrogen optionally may be provided directly to the reactor 3 via a reactor nitrogen stream 6. In such instances, the reactor 3 may also include a nitrogen feed inlet (not shown) constructed and arranged to receive the reactor nitrogen stream 6. Additionally or alternatively, nitrogen optionally may be provided via the feed nitrogen stream 5 and the reactor nitrogen stream 6. Alternatively, if multiple reactors (e.g., a first reactor, a second reactor, a third reactor, etc.) are present, a separate nitrogen stream may be provided to the second reactor and/or the third reactor.

[0080] In any embodiment, a hydrogen (Eh) stream 7 may also be provided to the reactor 3. In such instances, the reactor 3 may also include a hydrogen feed inlet (not shown) constructed and arranged to receive the hydrogen stream 7.

[0081] The catalyst present in the reactor 3 may include a mesoporous or microporous molecular sieve material as described herein (e.g., a zeolite, a zeotype, an aluminosilicate, a SAPO, an A1PO), at least one transition metal as described herein and substantially no intentionally added chlorine. In any embodiment, the catalyst may comprise a zeolite comprising an eight-membered ring, a ten-membered ring, a twelve-membered ring, or a combination thereof. In any embodiment, the zeolite may have a framework structure as described herein, for example, a FAU, LTL, BEA, MTW, MEI, or MOR framework structure, preferably, the zeolite may be selected from the group consisting of zeolite L, zeolite Y, and US-Y. In any embodiment, the transition metal may be a Group 10 metal (e.g., Pt) and be present in amounts as described herein, for example, about 0.05-5.0 wt%, based on total weight of the catalyst. In any embodiment, the catalyst may further comprise one or more of: a binder as described herein (e.g, silica, silica-alumina, alumina, titania, zirconia, Group 1 metal oxides, Group 2 metal oxides); a promoter metal as described herein (e.g., Re, Sn, Ga, In, Ir, Ga, Ge, Rh, Ru, Cu); an alkali metal as described herein (e.g., Na, K); and an alkaline earth metal as described herein (Mg, Ca, Ba). In any embodiment, the binder may be present in an amount of about 1.0 wt% to about 95 wt% based on total weight of the catalyst and/or the promoter metal may present in an amount of about 0.010 wt% to about 10 wt% based on total weight of the catalyst. In any embodiment, the catalyst may comprise no binder.

EXAMPLES

General Methods

Gas Chromatography (GC)

[0082] The following provided below was the GC set-up and method performed in Example 2

Front Inlet (leads to column 1)

• Split/Splitless inlet - Split Mode, 25: 1 split

• 250°C

• 3 mL/min septum purge • Total flow: 81 mL/min

Back Inlet (leads to column 2)

• Same as front inlet

Column 1

• 60 m x 0.32 mm ID x 5 um film DB-1

• th carrier gas

• Ramped flow mode: 3 mL/min, hold 22 min; ramp 99 mL/min to 5 mL/min, hold 9.5 min

Column 2

• 60 m x 0.25 mm ID x 0.5 um film DB-Wax

• Lh carrier gas

• Constant flow mode: 3 mL/min

Oven

• Start at 35°C, hold 5 min; ramp 100°C/min to 80°C, hold 9.5 min; ramp 10°C/min to 115°C, hold 0 min; ramp 25°C/min to 225°C hold 8.6 min - total run time 31.45 min

Front Detector (FID)

• 275°C

• 40 mL/min H2; 400 mL/min zero air

• N2 makeup; constant column + makeup = 30 mL/min

• Data Rate: 50 Hz

Back Detector (FID)

• 275°C

• 40 mL/min H2; 400 mL/min zero air

• N2 makeup; constant column + makeup = 30 mL/min

• Data Rate: 50 Hz

Example 1— Catalyst Preparation

[0083] Catalysts A, B, and C used in the example below were commercially available USY zeolites with FAU frameworks that had bulk Si: AI2 ratios in the range of 53 to 388. The catalysts were bound with a silica binder in the ratio of 80:20 zeolite to binder, and then steamed in 100% steam at a temperature and for an amount of time listed below in Table 1 to further reduce acidity. After steaming, they were impregnated with 0.9 wt% Pt using tetramine platinum nitrate. Alternative Pt sources include, for example, tetraamine platinum hydroxide, chloroplatinic acid, and a combination thereof. Additives or pH adjusters (e.g. NaOH or NH4OH) can optionally be added to improve metal dispersion. The catalysts were reduced in H2 and then sulfided in 2 wt% H2S before being loaded into the reactor. Sulfidation was performed by drying the catalyst in flowing N2 at 120°C for 1 hour, ramped to 300°C, and held for 30 minutes. The catalyst was then reduced in flowing H2 by ramping to 500°C and holding for 5 hours. Next, the catalyst was sulfided in flowing 10% H2S for 6 hours. Finally, excess S was removed by flowing H2 while cooling.

[0084] Details of Catalysts A, B, and C are summarized in Table 1 below.

Table 1-Catalyst Properties

Example 2— Catalyst Testing and Results

[0085] Catalysts A, B, and C were tested in a 16-channel fixed bed unit. Normal heptane was used as a model compound feed. Nitrogen was supplied using pyridine in concentrations of either 7 or 28 ppm by weight of N. The reaction was performed at 500°C, 350 psig, 5: 1 H2 to heptane ratio, and a WHSV (n-Heptane basis) of 10 h ¹ . The total effluent of the reactor was delivered to and analyzed by gas chromatography as described above.

[0086] The testing results for Catalyst A, B, and C with two are shown in FIGS. 2-6.

[0087] FIG. 2 illustrates yield of toluene as a function of time on stream (TOS) at different concentrations of nitrogen for Catalysts A, B and C. As can be seen in FIG. 2, the yield of toluene was constant across nitrogen feed concentrations in the range of 0-28 ppm nitrogen for Catalysts A, B and C. Both the maintenance of activity and selectivity are unique to non chloride based catalysts (Catalysts A, B and C) because the acid function was not removed as a chloramine during the reaction

[0088] Acid sites on a bifunctional catalyst can also catalyze unselective reactions such as paraffin cracking to liquid petroleum gas (LPG) (C3 and C4 paraffins) as well. For catalysts that have excess acid sites, the presence of nitrogen in the feed can actually temper these unselective reactions, decreasing the selectivity to less valuable LPG, which in turn may increase the liquid yield from the process. FIG. 3 illustrates yield of LPG as a function of TOS at different concentrations of nitrogen for Catalysts A, B and C. As shown in FIG. 3, the catalysts with the lower Si: AI2 ratios had a larger decrease in LPG yields under these conditions. [0089] FIGS. 4 and 5 illustrate LPG and toluene selectivities, respectively, as a function of TOS at different concentrations of nitrogen for Catalysts A, B and C. FIG. 6 illustrates yield of Ci+Ce and C2+C5 metal catalyzed cracking products as a function of TOS at different concentrations of nitrogen for Catalysts A, B and C. FIGS. 2-5 together appear to demonstrate that the nitrogen addition decreased the undesirable cracking reaction, while not affecting the preferred aromatization reaction. This was additionally supported by FIG. 6, which showed the combined yields of C1+C6 and C2+C5, which are believed to represent metal catalyzed cracking products.