JPS6391143A - Catalyst composite for converting hydrocarbon - Google Patents

Abstract

(57) [Abstract] This bulletin contains application data before electronic filing, so abstract data is not recorded.

Description

DETAILED DESCRIPTION OF THE INVENTION Field of the Invention This invention relates to novel catalyst complexes for hydrocarbon conversion, particularly for the dehydrocyclization of aliphatic hydrocarbons to aromatics. More specifically, the novel catalyst complex is capable of converting 06 and higher paraffins to the corresponding aromatics with a high degree of selectivity, thereby allowing for the facile production of large quantities of aromatics.

In the past, well-known catalytic reforming processes have been used to convert syrialiphatic hydrocarbons to aromatics. In catalytic reforming, a hydrocarbon feedstock, typically a petroleum naphtha fraction, is contacted with a Group VIII metal-containing catalyst complex to produce a reformate product with increased aromatic content. Naphtha fractions typically range from 10 to about 38°C
It is a full boiling range fraction having an initial boiling point of 163 to about 219°C. Such full boiling range naphthas contain significant amounts of 06 and above paraffinic hydrocarbons and 06 and above naphthenic hydrocarbons. As is well known, these paraffinic and naphthenic hydrocarbons are converted to aromatics by various reaction mechanisms. These mechanisms include dehydrogenation, dehydrocyclization, isomerization followed by dehydrogenation. Naphthenic hydrocarbons are converted to aromatics by dehydrogenation.

Paraffinic hydrocarbons may be converted to desired aromatics by dehydrocyclization or may be isomerized.

It is therefore clear that there are many reactions that take place in the catalytic reforming zone, and therefore a typical reforming catalyst must be capable of producing many reactions to be useful in a commercially viable reaction system. .

Since the reaction mechanisms that proceed in catalytic reforming are complex and numerous, attempts have recently been made to develop highly specific catalysts that convert only specific reactive species into aromatics. Such catalysts offer advantages over typical reforming catalysts, which must be able to participate in many reaction mechanisms.

In this respect, current research is directed in particular towards the production of catalysts for the conversion of paraffinic hydrocarbons containing 6 or more carbon atoms into the corresponding aromatic hydrocarbons. Such catalysts appear to be more layer specific with respect to the final product compounds, resulting in a reduction in undesirable side reactions such as hydrocracking. As those skilled in the art know, it is desirable to obtain a large number of aromatics. Demand in the petrochemical industry as a result of the high aromatic content of gasoline and lead phase reduction makes C6-C8 aromatics highly desirable products. Therefore, it is not worth much 0
It would be highly advantageous to have a highly selective catalyst complex for converting 6+ paraffins to higher value 06+ aromatics.

OBJECTS AND EMBODIMENTS It is therefore a principal object of the present invention to provide a catalyst composite for hydrocarbon conversion and methods of making and using the same. The general objective is to provide a process for converting 06 or higher .xi. rough-in hydrocarbons, especially C6-cs' .xi. rough-in hydrocarbons, to aromatics.

Accordingly, a broad aspect of the present invention is directed to a catalyst composite consisting of a non-acidic zeolite, a catalytically effective amount of a Group VIII metal component, and a silica support matrix derived by high pH gelation of an alkali metal silicate. There is.

Another broad aspect of the invention provides a hydrocarbon feedstock and a non-acidic zeolite under hydrocarbon conversion conditions, a catalytically effective amount of a
A method for converting hydrocarbons comprising contacting a group (1) metal component with a catalyst complex consisting of a silica support matrix derived from high pH gelation of an alkali metal silicate.

A further aspect of the present invention is a method for making a catalyst composite comprising combining a Group VIII metal component, a non-acidic zeolite, and a silica support matrix derived from high pH gelation of an alkali metal silicate. .

These and other objects and aspects will become apparent from the more detailed description of the invention below.

BACKGROUND OF THE INVENTION Aluminosilicates containing alkali metals are well known in the art. For example, U.S. Pat. No. 3,013,986, issued December 9, 1968, discloses alkali metal supported L-zeolites. In particular, this document indicates that potassium and potassium/sodium type L zeolites are the preferred starting materials for alkali metal supported L zeolites. This document teaches that an alkali metal-supported molecular sieve containing an alkali metal inside a zeolite molecular sieve can be produced by contacting a dehydrogenated molecular sieve with an alkaline earth metal vapor. However, this document does not disclose a catalyst composite consisting of a non-acidic zeolite, a catalytically effective amount of a Group VIII metal component, and a silica support matrix derived by high pH gelation of an alkali metal silicate. Furthermore, this document does not disclose that such composites have any use as hydrocarbon conversion catalysts.

U.S. Patent No. 3.376.21 issued April 2, 1968
In No. 5, the carrier is (1) a refractory inorganic oxide adsorbent and (
2) from a Group VIII metal-containing cocatalyst solid support consisting of a mordenite-structured zeolite, on which about 10 to 1000 ppm by weight of a metal selected from the group consisting of alkali metals, alkaline earth metals, and mixtures thereof is deposited based on the zeolite; A hydrocarbon conversion catalyst is disclosed. This document teaches that a support consisting of a mordenite-type zeolite and a refractory oxide is cocatalytic.

This document teaches that the cocatalytic refractory oxide can be a silica gel or even a silica-alumina.

However, this document emphasizes that alumina is the preferred refractory oxide. Furthermore, the only example of a refractory support derived by gelation is an alumina support derived from an alumina sol, which is well known to be acidic;
Here, gelation is carried out by neutralization with ammonia. Therefore, this document does not disclose the catalyst composite of the present invention. First, the non-acidic zeolite of the present invention is unlikely to have a catalytic effect on the reaction of interest. Rather, it is believed that the non-acidic zeolite modifies the Group VIII metal catalyst component of the catalyst complex but does not promote the dehydrocyclization reaction. Secondly, there is no disclosure of the use of IJ Lux, a silica carrier derived from high pH gelation of alkali metal silicate sols.

This document discloses little regarding the silica gel cocatalyst support source disclosed herein. Furthermore, the surprising and unexpected results obtained by using the conjugates of the present invention are disclosed.

U.S. Patent No. 3,755,4 issued August 28, 1973
No. 86 is Li, N impregnated with 03 to 1.4% platinum.
Discloses a method for dehydrocyclizing C6-Cl0 hydrocarbons having at least a C6 main chain using zeolite X or Y or 7-Osiasite in a or a.

However, from the outside this document shows that non-acidic zeolite, No. VII
There is no disclosure of the advantages to be derived by utilizing a catalyst composite consisting of a silica support matrix derived by high pH gelation of a Group I metal component and an alkali metal silicate. Similarly, U.S. Patent No. 3.819.507 issued June 25, 1974 and U.S. Patent No. 3.832.414 issued August 27, 1974 are Although the method is disclosed, it does not teach the uses and advantages to be derived from the use of the catalyst according to the invention.

U.S. Patent No. 4.140.32 issued August 1, 1978
No. 0 has exchangeable cations of which at least 90% are alkali metal ions selected from the group consisting of ions of sodium, lithium, potassium, rubidium and cesium and of the group consisting of metals of group VIII, tin and germanium. Discloses a method for dehydrocyclizing aliphatic hydrocarbons using L-type zeolite containing at least one metal selected from the following. This document does not disclose the catalyst composite of the present invention in that it does not disclose a bonded catalyst system in which the support matrix is derived from high pH gelation of an alkali metal silicate sol. November 2, 1983
U.S. Patent No. 4.417.083, issued on the 2nd, is 6.5
Discloses a dehydrocyclization method using a substantially non-acidic zeolite having a pore diameter of A or more and containing at least one metal selected from the group consisting of platinum, rhenium, iridium, tin and germanium. There is. In addition, this catalyst contains sulfur and alkali cations. However, in this literature, the high p of alkali metal silicate sols is
There is no disclosure of catalysts with silica support matrices induced by H-gelation.

U.S. Patent No. 4,416, issued November 22, 1983,
No. 806 is a zeolitic crystalline aluminosilicate supplemented by more than 90% alkali cations and having a pore diameter of 65 angstroms or more with platinum, rhenium as carbonyl, and other paraffinic dehydrogenation rings containing sulfur. discloses a chemical catalyst.

This document also does not disclose the catalyst composite for dehydrocyclization according to the present invention. Although this document contains extensive disclosure of using alumina or clay binders, it does not disclose any binders similar to the present invention.

Recent U.S. Patent No. 4430, issued February 7, 1984;
No. 200 discloses a hydrocarbon conversion catalyst consisting of a high silica zeolite, such as mordenite molten olide Y, base exchanged with an alkali metal. Although this document teaches a silica support matrix, it is not comparable to the matrix of the present invention, which is induced by high pH gelation of an alkali metal silicate sol. Moreover, this document merely discloses the use of conventional catalysts in the cracking step rather than in the dehydrocyclization step.

Recent U.S. Patent No. 4,44 issued May 15, 1984
No. 8.891 discloses a dehydrocyclization catalyst consisting of L zeolite soaked in an alkaline solution of at least 11 p, H for a time and temperature effective to increase the period of time the catalyst remains active. are doing. In addition, this catalyst
Contains Group I metals.

However, this document does not disclose the use of carrier matrices similar to the present invention.

In short, a non-acidic zeolite, a catalytically effective amount of Part V
Group I metal component and high pH of alkali metal silicate sol
No catalyst composition is known in the art for the conversion of hydrocarbons, particularly for the dehydrocyclization of paraffins of 06 and above to aromatics, which consists of a silica support matrix derived from gelation. Furthermore, such new catalysts and the additional benefits derived from their use were also unknown in the art.

Briefly reiterated, the present invention relates to a catalyst composition consisting of a non-acidic zeolite, a catalytically effective amount of a Group Vl metal component, and a silica support matrix resulting from high pH gelation of an alkali metal silicate sol. In addition, the present invention provides 0
It has particular use as a catalyst for the dehydrocyclization of paraffins of 6 or more, especially C6-Cl0 paraffins.

As previously pointed out, it is an essential feature of the catalyst of the present invention that it contains non-acidic zeolite. °゛Non-acidic zeolite”
' is to be understood to mean that substantially all of the cation exchange sites of the zeolite are occupied by non-hydrogen cationic species. Preferably such cationic species are alkali metal cations, although other cationic species may also be present. Regardless of the actual cation species present at the exchange sites, the non-acidic zeolites of the present invention have nearly all of the cation sites occupied by non-hydrogen cations, thereby rendering the zeolite nearly fully cation-exchanged and non-acidic. ing. Many means of obtaining highly cation-exchanged zeolites are well known and there is therefore no need to elaborate on such means here. The non-acidic zeolite of the present invention has a denaturing effect on Group VIII catalytic metals and is substantially inert to the reaction. Thus, the non-acidic zeolite support of the present invention is non-catalytic and is an essential feature of the present invention.

Representative non-acidic zeolites that can be utilized in the present invention are X-zeolite, Y-zeolite, and mordenite. L-zeolite is particularly preferred in the practice of this invention. Of course, all of these zeolites must be of the generally non-acidic type mentioned above, so that the cation-exchangeable sites are almost completely cation-exchanged by non-hydrogen cationic species. Also, as per the above, the cations occupying the cation exchangeable sites will typically be one or more alkali metals including lithium, sodium, potassium, rubidium and cesium. Thus, the non-acidic zeolite of the present invention can be a sodium form of X-zeolite, Y-zeolite or mordenite. A particularly preferred non-acidic zeolite for the practice of this invention is the potassium type L-zeolite. However, it should also be understood that the non-acidic zeolites of the present invention may contain other than alkali metal cations such as sodium and potassium in the cation exchangeable sites.

Regardless of the particular non-acidic zeolite utilized, the catalysts of the present invention contain catalytically effective amounts of nickel components, rhodium components,
It also includes a catalytically effective amount of a Group VIII metal component, including a palladium component, an iridium component, a platinum component, and even mixtures thereof. Particularly preferred among the Group VIII metal components is platinum.

It is believed that for the Group VIII metal component to achieve maximum catalytic effectiveness, this component should be supported on a non-acidic zeolite rather than a silica support matrix. Therefore, it is preferred that the Group Vl metal component is substantially supported on the non-acidic zeolite.

The Group VIII metal component may be deposited onto the non-acidic zeolite by any suitable means known in the art. For example, a non-acidic zeolite may be impregnated with a platinum component from a suitable solution, such as a dilute solution of chloroplatinic acid, and then the platinum-loaded non-acidic zeolite may be bonded to a silica support matrix. Alternatively, the Group VIII metal component may be deposited on the non-acidic zeolite by ion exchange, in which case some of the cation exchange sites of the non-acidic zeolite are
Contains Group II metal cations. After ion exchange, the Group VIII metal may be subjected to low temperature oxidation prior to the reduction step.

A non-acidic zeolite carrying a Group Vl metal component may then be bonded to the silica support matrix.

As explained in more detail below, a non-acidic zeolite is first bonded to a silica support matrix, and then a Group V metal component is preferably bonded to the non-acidic zeolite in a manner that results in selective deposition of the Group V metal component. may be selectively mixed with the zeolite and carrier matrix.

Regardless of the method by which the Group VIII metal component is deposited, a catalytically effective amount of any Group VIII metal component can be used. The optimum Group Vl metal component content is generally determined by which Group V
It depends on whether the Group I metal component is used in the catalyst of the present invention. However, generally about 0.0
1 to about 5.0 weight percent of the Group VIII metal component may be suitably deposited on the zeolite.

It should also be understood that best results are obtained when the Group Vl metal component is well dispersed on the non-acidic zeolite. Group V metal components are most effective in reduced conditions.

Any suitable means of reducing the Group Vl metal component can be used, and many of these are well known in the art. For example, after deposition on non-acidic zeolite, VI
The Group II metal component may be contacted with a suitable reducing agent, such as hydrogen, at an elevated temperature for a predetermined period of time.

It is contemplated by the present invention that in addition to including a Group VIII metal component, the present catalyst may include other metal components known to have catalyst modifying properties. Such metal components include rhenium, tin, cobalt, indium, gallium, lead, zinc,
Contains components such as uranium, thallium, dysprosium, and germanium. The inclusion of such metal components has been found to be advantageous in catalytic reforming as promoters and/or extenders. Accordingly, it is within the scope of the present invention to advantageously include catalytically effective amounts of such modifiers in the catalysts of the present invention to improve performance.

Regardless of the particular Group V metal component and catalyst modifier combined with the catalyst compositions of the present invention, another essential feature of the present invention is that the high pH gelation of the alkali metal silicate sol induces silica carrier matrix. Silica support matrices are well known in the art. Carrier matrices of this type find widespread use in the petroleum and petrochemical industries. It is particularly used to bond molecular sheets in various separation and catalytic processes. However, as explained further below, the silica support matrix of the present invention derived from high pH gelation of an alkali metal silicate sol provides surprising and unexpected advantages in the present invention.

As is well known in the art, a silica support matrix can be used to increase the physical strength of the catalyst. Therefore, by bonding a non-acidic zeolite to a silica carrier matrix, a catalyst with increased physical strength can be obtained. In addition, the combination of non-acidic zeolites produces forms suitable for use in catalytic conversion processes. For example, by using a silica support, the catalyst of the present invention can be shaped into spheres. It is well known that the use of spherical shapes is advantageous for various applications. In particular, when the catalyst of the present invention is placed in a continuous moving bed system, the spherical shape enhances the ability of the catalyst to move easily through the reaction zone. Of course, other shapes can also be used to advantage. Therefore,
The catalyst of the present invention may be formed into extrudates, saddles, and the like. Regardless of the specific shape of the silica support matrix,
Sufficient non-acidic zeolite and silica support matrix should be used such that the catalyst composition contains about 25 to 75 weight percent non-acidic zeolite based on the weight of zeolite and support matrix. Composites containing about 50% by weight non-acidic zeolite based on the weight of the zeolite and carrier matrix are preferred. In addition, the non-acidic zeolite microcrystals should be uniformly dispersed throughout the silica support matrix. This uniform distribution of non-acidic zeolite imparts improved particle strength properties and reactivity to the catalyst composite.

Another essential feature of the invention is that the silica support matrix is derived from high pH gelation of an alkali metal silicate sol. As used herein, the term "high pH gelling" should be understood to mean gelling at a pH of 7 or higher. This high pH gelation provides two distinct advantages. First, for high pH gelling, non-acidic zeolites can be incorporated into the alkali metal silicate sol before gelling the carrier matrix without loss of crystallinity. As is well known, zeolites are sensitive to the pH of their environment. Therefore, zeolites dispersed in acidified sol may lose crystallinity during gelation.

This disadvantage can be overcome by the high pH gelation used in the present invention to induce the silica support matrix.

Since the easiest means of preparing the catalysts of the invention is to disperse non-acidic zeolites in alkali metal silicates prior to gelation, the high pH environment of gelation is ideal for making the catalyst complexes of the invention. Avoiding the concomitant possibility of zeolite loss. High pH gelling also avoids introducing acidic sites into non-acidic zeolites. The introduction of such acidic sites causes the zeolite to promote undesirable side reactions such as cranking.

A second advantage of deriving a silica support matrix by high pH gelation of an alkali metal silicate sol is that the final catalyst complex has surprising and unexpected selectivity for the production of aromatic hydrocarbons from paraffins of 0.6 and above. It is to bring about.

Although not fully understood, it is believed that high pH gelation of soluble alkali metal silicates results in a silica support matrix with increased interaction of the non-acidic zeolite with the silica of the support matrix. This interaction apparently results in modification of the Group VIII metal component to increase the overall selectivity of the catalyst for producing aromatics from paraffins of 06 and above.

Therefore, deriving a silica support matrix by high pH gelation of alkali metal silicates not only allows easy preparation of the final catalyst composite but also has surprisingly high selectivity for the production of aromatics of C6 and above. yielding a catalytic complex.

As is well known in the art, alkali metal silicate sols may be used as precursors to silica support matrices. Water glass (sodium silicate) has often been used as a precursor for support matrices. In addition, there are various known means of performing high pH gelation. However, the preferred alkali metal silicate and high pH gelation techniques were
No. 4,53'7866, issued Aug. 27, 2005, the contents of which are incorporated herein. In this preferred method, the lithium silicate sol is heated to a temperature of about 70 DEG C. or higher, thereby gelling the sol. Thereafter, the gelled lithium silicate sol is subjected to a washing process to remove lithium and thereby fix the shigel. Lithium silicate sols that can be used in the present invention will have a S i O2/L i 20 molar ratio of up to about 25:1. Particularly preferred lithium silicate is S
iO2/L i02 molar ratio is about 4:0 to about 8
:1. All of these lithium silicate sols have a pH of about 7 or higher, and preferred lithium silicate sols have a pH of about 1
0 to about 110 pH.

Since the lithium silicate sol can be gelled by heating without the need to adjust the pH with a gelling agent (typically an acid), the above-mentioned high pH gelling is possible. Accordingly, in making the catalyst composite of the present invention by the method described in the previously mentioned US Pat. No. 4,537,866, a non-acidic zeolite is dispersed in a lithium silicate sol. Thereafter, a lithium silicate sol having particles of a predetermined shape is generated. The shaped particles are then packed into approximately 70
The shaped particles form a gel when heated to temperatures above .degree. The lithium silicate gel containing non-acidic zeolite is then subjected to a washing process to remove lithium from it. This washing step fixes the gel.

As those skilled in the art know, many methods can be used to make shaped particles of non-acidic zeolite-containing lithium silicate sol. These include extrusion, pilling, molding, etc. Among the many known methods, a particularly preferred method for making shaped particles of the present invention is the oil drop method. In the oil drop method, sol particles are formed as droplets. Typically, these drops are formed by directing the sol through a suitable orifice or from a rotating disk. The droplets are then allowed to fall into a suspension medium such as oil. As the drop passes through the oil suspension medium, it assumes an elliptical spherical shape. The diameter of the ellipsoidal particles may be controlled by adjusting the diameter of the orifice through which the droplets flow and/or the rate of oscillation of the falling head. As the non-acidic zeolite-containing sol droplets pass through the suspension medium, heating to a temperature of about 70° C. or higher causes the sol to gel. The gelled particles are then collected, aged and subjected to a washing step to remove the lithium.

Thus, a non-acidic zeolite bound within a silica support matrix is derived by high pH gelation of an alkali metal silicate, preferably lithium silicate.

As previously indicated, the non-acidic zeolite is preferably blended with a silica support matrix and then blended with the Group VIII metal component. Furthermore, as already indicated, Section V
Preferably, the Group III metal component is substantially supported on the non-acidic zeolite. Of course, any suitable means of accomplishing these preferred steps may be utilized in the present invention. However, a particularly preferred method is to use selective ion exchange techniques, whereby the Group VIII metal component is deposited substantially on the non-acidic zeolite rather than on the silica support matrix.

Selective deposition of platinum onto the non-acidic zeolite as opposed to the silica support matrix can be achieved by controlling the pH of the exchange solution to a value of 8 or less. Silica support matrices are known to be cation exchangers at pHs above about 8. In contrast, the ion exchange capacity of zeolite is p
No H dependence. Thus, when the Group VIII metal component is deposited by ion exchange with an ion exchange solution having a pH of about 8 or higher, the Group VIII metal component is deposited on the silica carrier.
IJ Lux tends to deposit on both non-acidic zeolites. However, at pH below 8, the silica support matrix loses its cation exchange capacity. Thus, by using a cation exchange solution with a pH of about 8 or less, Part VI
The Group II metal component is almost selectively deposited only on the non-acidic zeolite. Adjust the pH of the cation exchange solution to about 4 to about 8.
It is particularly preferred to maintain the pH in the range of . This will result in selective deposition of the Group VIII metal component on the non-acidic zeolite rather than the silica support matrix.

Regardless of the method of manufacture, the catalyst composites of the present invention have particular application as hydrocarbon conversion catalysts. Accordingly, a hydrocarbon feedstock is contacted with the catalyst composite of the present invention under hydrocarbon conversion conditions. A wide range of hydrocarbon conversion conditions can be used and this depends on the particular feedstock and reaction to be performed. Generally, these conditions include a temperature of about 0 to about 816 degrees Celsius, a pressure of about atmospheric to about 100 atmospheres, and a temperature of about 0 to about 1
5 hr-1 (calculated on the basis of the liquid volume of the feed in contact with the catalyst divided by the volume of the conversion zone containing the catalyst per hour). Additionally, hydrocarbon conversion conditions may include the presence of a diluent such as hydrogen. In this case, the molar ratio of hydrogen to hydrocarbon can be from about 05:1 to about 30=1.

A particularly preferred application of the catalyst of the invention is as a dehydrocyclization catalyst, particularly for the dehydrocyclization of C6-08 non-aromatic hydrocarbons. Accordingly, a hydrocarbon feed consisting of C6-C8 non-aromatic hydrocarbons is contacted with the catalyst of the present invention under dehydrocyclization conditions. Dehydrocyclization conditions are from about 0 to about 68
95 kPag pressure, preferably about 0 to about 4137
kPag pressure, a temperature of about 427 to about 649°C, and a liquid hourly space velocity of about 0.1 to about IQhr''. Preferably, hydrogen can be used as the diluent. Hydrogen, when used, About 0.1 to about 10 moles of hydrogen can be recycled per hydrogen.

According to the invention, a hydrocarbon feedstock is contacted with the catalyst of the invention in a hydrocarbon conversion zone. This contact can occur in fixed bed systems,
This can be accomplished using catalysts in moving bed systems, fluidized bed systems, or batch operations. The hydrocarbon feedstock and optionally hydrogen-enriched gas as a diluent are typically preheated to the desired reaction temperature by suitable power heating means and then passed to the conversion zone containing the catalyst of the present invention. It will be understood, of course, that the conversion zone may be one or more separate reactors with suitable means in between to maintain the desired conversion temperature at the inlet of each reactor. Will.

It is also important that the reactants can be contacted with the catalyst bed in upflow, downflow or radial flow, the latter being preferred. In addition, the reactants may be in a liquid phase, a mixed liquid-vapor phase,
Alternatively, it can be in a vapor phase. Best results are obtained when the reactants are in the vapor phase.

When the catalyst of the invention is used in a dehydrocyclization process, the dehydrocyclization system consists of a reaction zone containing the catalyst of the invention. As previously indicated, the catalyst can be used within the reaction zone as a fixed bed system, a moving bed system, a fluidized bed system or as a batch operation, but in view of the operational advantages well recognized in the art, moving bed It is preferred to utilize the catalyst of the present invention in the system. In such systems, the reaction zone may be one or more separate reactors with heating means in between to compensate for the endothermic nature of the dehydrocyclization reaction occurring in each catalyst bed. .

A hydrocarbon feed stream, preferably consisting of C6-08 non-aromatic hydrocarbons, is contacted with a transfer catalyst in the reaction zone to effect dehydrocyclization.

After contacting the catalyst of the present invention, the hydrocarbon feedstock that has undergone dehydrocyclization is withdrawn from the reaction zone as an effluent stream and passes through cooling means into the separation zone.

In the separation zone the effluent can be separated into various components depending on the desired product. When hydrogen is utilized as a diluent in the reaction zone, the separation zone typically consists of a vapor-liquid equilibrium separation zone and a fractionation zone. Hydrogen-rich gas is separated from the aromatics-containing high octane liquid product produced in the dehydrocyclization zone. After separation, at least some of the hydrogen-rich gas may be returned to the reaction zone as a diluent. The remainder of the hydrogen-rich gas can be recovered for other uses. The high octane liquid product containing aromatics is then sent to a fractionation zone to separate the aromatics from the unconverted component feedstock.

These unconverted components may then be returned to the reaction zone for processing or to other steps for utilization elsewhere.

A wide variety of hydrocarbon feedstocks can be used in the process of the present invention. The feedstock utilized will, of course, depend on the correct application of the catalyst. Typically, hydrocarbon feedstocks that can be used in the present invention include naphthenes and paraffins, but may also include aromatics and olefins in some cases. Therefore, the groups of available feedstocks are straight-run naphtha, natural naphtha,
Contains synthetic naphtha, etc. Alternatively, straight-run naphtha and cracked naphtha can also be used advantageously. The naphtha feedstock can be a full boiling range naphtha or a fraction selected therefrom having an initial boiling point of about 10 to about 66°C and a final boiling point of about 163 to 219°C. The feedstock used in this invention is treated by conventional catalytic pretreatment methods such as hydrorefining, hydrotreating, hydrodesulfurization to remove substantially all of the sulfur, nitrogen,
and water-generated contaminants are preferably removed.

When using the catalyst of the present invention as a dehydrocyclization catalyst, it is preferred that the feedstock consists essentially of paraffins. This is of course because the purpose of the dehydrocyclization process is to convert paraffins to aromatics. Because of the value of C6-08 aromatics, it is further preferred that the hydrocarbon feedstock consists of 06-08 paraffin. However, regardless of the preferred embodiment of the hydrocarbon feedstock, the C6-C
In addition to the 8/ξ rough-in, naphthenes, aromatics, and olefins may also be included.

Examples are provided below to more fully demonstrate the advantages resulting from the invention. It is to be understood that the following examples are for illustrative purposes only and are not intended to unduly limit the broad scope of the invention.

It should be understood that there are three useful parameters in evaluating the performance of hydrocarbon conversion catalysts, particularly in evaluating and comparing dehydrocyclization catalysts. The first is 'activity', which is a measure of a catalyst's ability to convert reactants at specific reaction conditions.

A second catalytic performance criterion is "selectivity," which is a measure of the catalytic ability to produce high yields of the desired product.

The third parameter is “stability,” which is a measure of the catalyst's ability to maintain its activity and selectivity over time.
It is. The criterion of interest in the following examples is the selectivity of the catalyst. For purposes of the following, the catalyst of the present invention is exemplified as a dehydrocyclization catalyst and a measure of catalyst selectivity is the conversion of paraffinic reactants to aromatics.

BRIEF DESCRIPTION OF THE DRAWINGS Figures 1 and 2 are diagrams of catalyst selectivity for the production of aromatics as a function of time. In Figure 1, 2
Performance data for two catalysts are shown; Catalyst A and Catalyst B are not of the present invention. Figure 2 shows catalyst C of the present invention.
and test results for catalysts that are not of the present invention.

Example I A first catalyst consisting of a non-acidic zeolite bound to silica was prepared. In this example the silica support matrix was not derived by high pH gel techniques. In this catalyst, the non-acidic zeolite was potassium exchanged L zeolite. The catalyst was prepared by mixing L-zeolite and colloidal silica in varying amounts such that the final composite consisted of 10% by weight silica and 90% by weight L-zeolite based on the weight of silica and L-zeolite. The mixture was evaporated to dryness, ground, and extruded using about 5 g of polyvinyl alcohol as an extrusion aid. The extrudates were then calcined at 500°C.

The calcined extrudates were then subjected to an ion exchange step to deposit platinum thereon. Pt(NH3)4Cρ2/KCQ-/J
- An ion exchange solution was used. Then the extrudate was
It was subjected to an oxidation step and a reduction step at 0°C. Finishing catalyst is 087
It contained 7% by weight of platinum. This catalyst was designated as catalyst A. Although bonded to a silica-containing support matrix, Catalyst A was unsuccessful in the present invention because the support matrix of Catalyst A was not due to the high pH gelation technique of alkali metal silicate.

Example ■ In this example, a second catalyst was prepared. The catalyst was unbound L-zeolite in the potassium form. The unbound L-zeolite was subjected to an ion exchange step as shown in Example I to deposit the platinum component.

After deposition of the platinum component, approximately 350% of the unbound L-zeolite
An oxidation treatment was carried out in air at a temperature of 350°C, followed by a reduction process using hydrogen at a temperature of about 350°C. The finished catalyst contained 0.657% by weight platinum. This catalyst was designated as Hb, and n was not of the present invention.

In this Example, Catalyst A and Catalyst B were tested to determine their relative performance as dehydrocyclization catalysts. The test was carried out in a pilot plant consisting of a reaction zone containing the catalyst to be tested. Conditions in the reaction zone are 690 kPag
pressure, l, liquid hourly space velocity of Q hr, and 50
The reaction inlet temperature was 0°C.

Sufficient hydrogen was mixed with the feedstock prior to contacting the catalyst to give a hydrogen to hydrocarbon molar ratio of 10.0:1.0. The feedstock was a paraffin mixture of isoC6 + isoC7 + normal C6 and normal C7, with a small amount of alkylcyclopentane.

The hydrocarbon feed was contacted with a catalyst placed within the reaction zone and the reaction zone effluent was analyzed. In this test, both Catalyst A and Catalyst B were tested and the data obtained is shown in FIG. FIG. 1 is a graphical representation of catalyst selectivity for the production of aromatics as a function of time measured over a 6 hour period. In this example, the selectivity is 10 grams of aromatics produced per gram of feed converted.
Defined as multiplied by 0. As can be seen from Figure 1, Catalyst B showed higher selectivity for aromatic production than Catalyst A, with the exception of Period 3. Thus, unbound L-zeolite with supported platinum showed better selectivity for the production of aromatics than a catalyst comprising a platinum component and bound L-zeolite in a silica support matrix.

Example■ In this example a catalyst was made according to the invention.

Approximately 300 g of potassium type L-zeolite was
It was ground in a ball mill with 1382 g of lithium silicate sol having a 2/L i O2 of 6 and a pH of about 10.5. This sol was then dispersed as droplets in an oil-suspending medium. The sol droplets were now gelled at a temperature of about 100°C. The gel spheres were then aged in oil at a temperature of about 100-150° C. and a pressure of about 552 kPag for about 2 hours. After that, the aged spheres were heated to about 95°C with 0.15 mol KC.
Lithium was removed by washing with 14 liters of ρ solution for 2 hours.

The spheres were then dried at 95°C. After drying, the spheres were gradually heated to 610° C. over a period of 6 hours. Then the ball is 610
It was baked in dry air at ℃ for 2 hours.

The resulting spheres were potassium-type zeolites bound within a silica support matrix by high pH gelation of an alkali metal silicate sol. The composition contains 50% by weight of L-
It was zeolite and 50% by weight silica.

The calcined spheres were then subjected to an ion exchange process to deposit the platinum component substantially on the L-zeolite. The ion exchange solution was 0.03 mol Pt(NH3)4Cρ maintained at a pH below 8.
It was a 210.90 mol KC solution.

As previously indicated, it is possible to deposit substantially all of the platinum onto the L-zeolite by maintaining the pH below 8. The catalyst was then washed with water and dried at a temperature of about 95°C. After drying, the catalyst was oxidized at a temperature of 350°C and reduced in a stream of hydrogen at a temperature of about 350°C. The resulting catalyst contained 0.786% by weight of platinum. This catalyst according to the invention was designated as Catalyst C.

Example (2) An unbonded non-acidic zeolite catalyst was prepared in substantially the same manner as in Example (2). However, in this example the catalyst contained approximately 0.882% by weight platinum on potassium-type pore-zeolite. Therefore, this catalyst was almost the same as catalyst B of Example (2).

However, the catalyst of this example contained more platinum component. The catalyst prepared in this example was used as a catalyst.

Example 2 Catalyst C and Catalyst C were tested to determine the relative performance of the catalyst prepared according to the present invention and a catalyst consisting of unbonded L-zeolite containing platinum as dehydrocyclization catalysts. This test was conducted in a pilot plant substantially identical to that used to test Catalysts A and B in Example 2 above. However, since orange, a different test method was used in this example.

The conditions used during this test period for Catalysts C and D were: reaction zone inlet temperature of 500°C; The liquid hourly space velocity was Ohr', and the reaction zone pressure was 345 kPag. Hydrogen was mixed into the hydrocarbon feed prior to fusion with the catalyst. Sufficient hydrogen was used on a single pass basis so that the ratio of moles of hydrogen to moles of hydrocarbon feed was 5:1.

The method used in the test was to first combine the catalyst and feedstock with 41
Contacting was at a reaction zone temperature of 0°C. 410
The reaction zone inlet temperature of 0.degree. C. was maintained for 7 hours. The reaction zone inlet temperature was then increased to 500° C. for 3 hours. A temperature of 500° C. was then maintained during the 12 hour test period in which the reaction zone effluent was analyzed hourly by on-line gas chromatograph.

The feedstock used in this example had the following analysis: C3/C4/'C5/ξMiraffin 04 wt% C6
Paraffin 69.5% by weight C6 naphthene
0.7% by weight 07ξ Rough-in 2
1.4% by weight total 100.0% by weight The test results are shown in FIG. In the following discussion, for Figure 2,
The selectivity is the same as that given in Example ① above.

Surprisingly and unexpectedly, the data in Figure 2 shows that the catalyst of the present invention exhibits significantly higher selectivity for the production of aromatics than the unbound L-zeolite and platinum catalyst. As shown by the data in FIG. 1, this is contrary to the results obtained in Example 2 above. In Example 2, the unbonded L-zeolite and platinum catalyst performed better than the silica-bound L-zeolite and platinum catalyst.

However, in this example, the silica-bound L-zeolite and platinum catalyst exhibited higher selectivity for aromatic production than the unbound L-zeolite and platinum catalyst. It can therefore be concluded that the surprising and unexpected results achieved by the present invention are caused by the fact that the silica support matrix of catalyst C is derived from high pH gelation of an alkali metal silicate sol. Catalyst A, a platinum-containing silica-bonded L-zeolite catalyst, did not exhibit superior selectivity compared to a platinum-containing unbound L-zeolite catalyst. The difference in relative selectivity shown in this example and Example It is not due to

As previously indicated, non-acidic zeolites are non-catalytic and merely act to modify the catalytic Group VIII metal component within the system.

Although it is not fully understood whether the incorporation of platinum-containing non-acidic zeolite into a silica support matrix by high pH gelation of an alkali metal silicate sol results in improved selectivity, It is believed that the interactions caused by the high pH gelling conditions between the two groups further modify the catalytic function of the platinum component. Such modification provides improved selectivity for the conversion of paraffins to aromatics.

[Brief explanation of the drawing]

FIGS. 1 and 2 are diagrams showing the relationship between time and selectivity. (5 others) 1. Reihiro (C Chikenzu City 41 s'/s Cao Huiyi procedural amendment (method) 1. Indication of the case 1966 Patent Application No. 2310-6 No. 6, person making the amendment Relationship to the incident Applicant Address Name Euohhi 0-・Inko+,” L-Thea
G4. Agent

Claims (1)

Claims: 1) A catalyst composite consisting of a combination of a non-acidic zeolite, a catalytically effective amount of a Group VIII metal component, and a silica support matrix derived by high pH gelation of an alkali metal silicate sol. 2) The composite according to claim 1, wherein the Group VIII metal component is a platinum component. 3) The composite according to claim 1, wherein the non-acidic zeolite is L-zeolite. 4) The composite according to claim 3, wherein the L-zeolite is a potassium type L-zeolite. 5) A composite according to claim 1, wherein substantially all of the catalytically effective amount of Group VIII metal component is supported on a non-acidic zeolite. 6) A composite according to claim 1, wherein the carrier matrix is derived by high pH gelation of a lithium silicate sol. 7) The composite of claim 1, comprising from about 0.01 to about 5.0% by weight Group VIII metal component, based on the weight of the zeolite, carrier matrix, and Group VIII metal component. 8) Approximately 2 based on the weight of zeolite and carrier matrix
A composite according to claim 1, comprising 5 to 75% by weight of non-acidic zeolite. 9) A hydrocarbon conversion process comprising contacting a hydrocarbon feedstock with a catalyst composite according to any of claims 1 to 8 under hydrocarbon conversion conditions. 10) The method of claim 9, wherein the hydrocarbon feedstock consists of C_6 to C_8 non-aromatic hydrocarbons. 11) the hydrocarbon conversion conditions are dehydrocyclization conditions;
A method according to claim 9.