JPS6324034B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The degree of conversion obtained by a cracking operation is such that the feedstock hydrocarbon having a normal boiling point of at least 221°C is converted into a hydrocarbon product having a normal boiling point below 221°C during the conversion stage. It can be defined as the percentage of volume that can be changed. Conversion rate is often used as a measure of the severity of commercial cracking operations. For fixed operating conditions, a more active catalyst will have a higher conversion than a less active catalyst. A high conversion rate gives the FCC device a wide range of operation. For example, increasing the conversion rate can increase the feed rate, or can maintain feed conversion at a high rate under a constant feed rate.

Selectivity in converting the feed to the desired hydrocarbon products is also important. The primary desired product is a naphtha boiling range hydrocarbon, i.e. approximately 24°C to
This product has a standard boiling point of 220℃. Other possible conversion products are usually less valuable than naphtha. For example, feed conversion may produce coke, hydrogen, and by-products that normally have no economic value, such as light paraffins, methane, ethane, and propane. Although some coke formation is necessary as a process heat source, coke formation at the expense of naphtha is undesirable. In contrast to light paraffins, light olefins can be economically attractive products. _C3 and _C4 olefins can be utilized as feedstocks for other hydrocarbon conversion processes, e.g. alkylation of isoparaffins to form high-octane gasoline components, or as feedstocks for petrochemical-type operations, e.g. polymerization. It is.

Recent trends in removing octane improvers such as lead and manganese from commercial gasoline have increased the importance of improving the simple octane numbers of the various components that make up the gasoline pool. Catalytic cracking naphtha is an important source of gasoline in the United States, but is often among the lower octane components used in unleaded gasoline pools.
Although FCC derived naphtha can be improved in quality by some conventional refining methods such as reforming, if the octane number of FCC naphtha can be raised to an acceptable level by improving the catalytic cracking process itself, Expenses for additional purification can be avoided. According to the present invention, it is possible to increase the aromatic content, olefin content, or both contained in catalytically cracked naphtha, thereby increasing its octane number. Furthermore, the process of the present invention can increase the octane number of a potential gasoline pool by providing additional light olefins for alkylation.

There are a few patents that suggest improvements to cracking catalysts to increase the octane number of FCC naphtha. This improvement usually involves adding metals with moderate dehydrogenation activity to the catalyst particles. For example, US Pat. No. 3,835,032 states:
It has been suggested that silver-exchanged or copper-exchanged Y-type zeolite components be used in cracking catalysts to increase the aromatic content of naphtha products. US Pat. No. 3,929,621 suggests the use of copper-exchanged Y-type zeolite for the purpose of increasing the aromatic compounds and olefins contained in cracked naphtha. US Pat. No. 3,994,800 states:
It has been suggested that modified Y-type zeolites be used to increase the olefin content of catalytically cracked naphthas.
U.S. Pat. No. 3,788,977 discloses the addition of uranium or platinum on an alumina support within cracking catalyst particles or separate particles that are introduced into circulation as particulate solids inventory in a cracking system. It has been suggested that this increases the dehydrogenation and cyclization reactions that occur within the cracking reaction column.

Metals that have substantial dehydrogenation activity also generally have substantial activity for oxidation catalysts. The desire to promote efficient combustion of carbon monoxide during cracking catalyst regeneration has led to the use of highly active metals in cracking catalysts. In some commercial cracking systems, catalyst regeneration is performed by incomplete carbon monoxide combustion, in which a substantial amount of carbon, e.g., greater than 0.2% by weight, typically about 0.25%, is deposited on the regenerated catalyst. ~0.45
% by weight of residual carbon typically remains. The flue gases emerging from cracking catalyst regeneration operations in incomplete combustion regimes are characterized by a relatively low carbon dioxide/carbon monoxide volume ratio. The amount of oxygen introduced into the catalyst regenerator operating in the incomplete combustion mode is such that the amount of oxygen introduced into the flue gas downstream of the dense catalyst bed causes afterburning, i.e., overheating of the flue gas. It is usually necessary to carefully limit carbon monoxide to prevent its combustion.

Most fluid catalytic cracking systems currently use zeolite-containing catalysts that exhibit high activity and selectivity, especially when the coke concentration on the catalyst is relatively low. Therefore, in order to obtain high activity and selectivity, it is desirable to regenerate the zeolite-containing catalyst so as to reduce the amount of coke as much as possible. It is also desirable to perform carbon monoxide combustion as completely as possible during catalytic regeneration to obtain additional heat, especially when the coke concentration on the spent catalyst is low due to high catalyst selectivity. One way to reduce the amount of coke on the regenerated catalyst and to enhance the combustion of carbon monoxide for process heating is to use a dense phase in the regenerator catalyzed by an active combustion-promoting metal. This is the combustion of carbon monoxide in the catalyst bed. The metal is an integral component of cracking catalyst particles.
Or, when the active metal is associated with a support other than a catalyst, it is conventionally used either as a component of another particulate additive. Additive particles are mixed with catalyst particles in the circulating particulate solids inventory. Various methods have been suggested for using carbon monoxide combustion promoting metals in cracking systems. U.S. Pat. No. 2,647,860 discloses that 0.1 to 1% by weight of chromic oxide is added to the cracking catalyst to promote the combustion of carbon monoxide to carbon dioxide;
Moreover, it has been proposed to prevent afterburning. No. 3,808,121 proposes introducing relatively large sized particles containing carbon monoxide combustion promoting metals into a cracking catalyst regeneration device. A circulating particulate solids inventory, consisting of catalyst particles of relatively small size, is circulated between the cracking reactor and the catalyst regenerator, while the combustion-promoting particles are trapped within the regenerator due to their size. remain. Pro-oxidant metals such as cobalt, copper, nickel, manganese, copper-chromite, etc. impregnated onto inorganic oxides, such as alumina, are disclosed. Belgian patent publication no.
No. 820181 suggests using catalyst particles containing platinum, palladium, iridium, rhodium, osmium, ruthenium or rhenium to accelerate the oxidation of carbon monoxide in a catalyst regenerator. Traces to 100 ppm during catalyst production or during cracking operations by adding combustion-promoting metal compounds to the hydrocarbon feed.
amount of metal is added to the catalyst particles. The addition of this promoter metal to the cracking system substantially increases the formation of coke and hydrogen;
It is said to reduce product selectivity. Catalyst particles containing promoter metals can be used alone or can be circulated in a physical mixture with catalyst particles that do not contain combustion promoting metals. U.S. Patent Nos. 4,072,600 and 4,093,535 each include 0.01 to 50 ppm based on total catalyst inventory.
The use of combustion promoting metals in cracking catalysts at concentrations of .

It is recognized in the cracking art that metals that actively catalyze dehydrogenation and oxidation reactions can have serious deficiencies when used in cracking catalysts. The presence of such metals in cracking catalysts increases the formation of coke, hydrogen, and light paraffin gases such as methane, as seen, for example, in the refining of nickel-rich hydrocarbon feeds. In this technical field,
Several methods have been suggested to obtain the benefits of using active metals in cracking catalysts without incurring losses in product selectivity. One approach is to avoid all hydrocarbons from contacting the catalytic metal. Only the oxidation activity of the metal is utilized because the metal remains in the catalyst regenerator (e.g., U.S. Pat. No. 3,808,121) or the pore opening is less than 5 Å and the small size (3-5 Å). The metal is incorporated into a zeolitic crystalline aluminosilicate having a cage of
3364136). In another attempt,
Using low concentrations of catalytic metals, the loss in selectivity due to the presence of the metal is replaced by an increase in available heat due to catalyzed carbon monoxide combustion and an increase in the selectivity of the zeolite due to the low residual coke content. It is an attempt to offset this.

On the other hand, improving the octane number of active metals and dehydrogenation
Attempts have been made to utilize the aromatization activity, on the one hand, and the carbon monoxide combustion and oxidation activities of active metals, but these two different activities have not been combined in a single cracking catalyst. This has not been successful because metals with carbon monoxide oxidation activity tend to build up coke, hydrogen, and light paraffin gases instead of valuable aromatics and olefins. According to the present invention, it is possible to simultaneously utilize both the dehydrogenation-aromatization activity and the oxidation activity of the active metal in a cracking catalyst.

Uniform pore opening ranging from 5.5 to 7.0 Å and 5.5 to
It is known to use crystalline aluminosilicate zeolites with a maximum cage dimension of 7.0 Å for catalytic cracking. For example, U.S. Pat. No. 3,758,403, no.
The specifications of No. 3849291 and No. 3856659 all contain zeolite ZSM-5 in two types of zeolite catalysts.
It has been suggested to use the above-mentioned crystalline aluminosilicates with larger pore openings and cages, such as Y-type zeolites.
U.S. Pat. No. 3,894,934 suggests the use of carbon monoxide combustion promoting components with ZSM-5 and large pore size crystalline alumina silicates. Active catalytic metal value (catalytic
U.S. Patent No.
3953366. Catalysts containing ZSM-5 are also disclosed in US Pat. Nos. 3,702,886 and 3,926,782. Crystalline silicates are described in U.S. Pat.
No. 4073865 and is described in each specification.

The present invention provides a method for converting feedstock hydrocarbons having a normal boiling point higher than 220°C, comprising: (a) a crystalline solid selected from zeolitic crystalline aluminosilicates and crystalline silicates; Contains 0.01 to 1000 ppm by weight of an active metal or active metal compound selected from platinum, palladium, iridium, rhodium, osmium, ruthenium, and copper arranged inside the crystal, calculated as an element based on the catalyst. A granular solid catalyst is circulated between a reaction zone and a catalyst regeneration zone, and the crystal structure of the crystalline solid is between 5.5 and 5.5.
defining a substantially uniform pore opening having a maximum diameter of 7.0 Å and a substantially uniform cage having a maximum cage dimension of 5.5 to 7.0 Å, thereby forming a raw material carbonization limiting contact between hydrogen and active metals;
(b) Contacting the feedstock hydrocarbons with a catalyst in a reaction zone under cracking conditions including the absence of added molecular hydrogen to form cracked hydrocarbons having a normal boiling point below 220°C, and forming particulate solids. The dehydrogenation and aromatization of aliphatic components in feedstock and cracked hydrocarbons is carried out by depositing coke on the material and contacting it with active metals located inside the crystalline solid in the reaction zone. (c) in a regeneration zone, burning off coke from the catalyst using molecular oxygen under catalyst regeneration conditions to form carbon monoxide; It relates to a process for the conversion of hydrocarbons, which consists in burning carbon oxide with molecular oxygen in contact with an active metal arranged inside a crystalline solid.

The improved product octane number obtained by the dehydrogenation activity of platinum and other catalytically active metals with a high degree of dehydrogenation activity makes it possible for the same metals to burn carbon monoxide and coke during cracking catalyst regeneration. can be synergistically combined with improved catalyst regeneration obtained by the oxidation activity of This is achieved by incorporating the active metal inside the crystals of a crystalline solid having uniform pore openings and cages with sizes in the range of 5.5-7.0 Å. This limits the contact between the hydrocarbon and the active metal, and favors the contact between the metal and the hydrocarbon, which has a relatively small molecular diameter, so that the crystalline aliphatic hydrocarbon preferentially contacts the active metal. do. Thereby, low-octane hydrocarbons are catalytically aromatized to form high-octane aromatics. Coke-forming hydrocarbons with large diameters are selectively excluded from contact with active metals, thereby limiting coke and hydrogen formation. Therefore, the total octane number of naphtha produced by the cracking method is improved. Low value _C2 ~ _C4
In contrast to paraffins, the formation of valuable _C2 - _C4 olefin by-products is encouraged. Moreover, the size of the pore openings and cages within the crystalline solid are large enough to provide access for the active metal to carbon monoxide and oxygen during catalyst regeneration, such that the active metal has a combustion promoting activity. It is possible to promote the combustion of carbon monoxide and coke in the catalyst regeneration device by using this.

The present invention is used in a catalytic cracking system for hydrocarbon feeds. Conventional catalytic cracking feeds typically include a mixture of aliphatic and aromatic hydrocarbons with boiling points above 221°C. The same cracking feedstock hydrocarbons that are normally purified in commercial catalytic cracking systems can be purified in cracking systems using the present invention. Suitable feedstocks include, for example, straight-run or partially refined petroleum distillates or kettle bottoms, such as by catalytic hydrorefining. Conventional gas oil fractions are therefore suitable, as are atmospheric and vacuum distillation residues. Also suitable are so-called synthetic feedstocks, such as coal oil, bitumen and shale oil. Suitable feeds may include recycled hydrocarbons that have already been subjected to cracking, such as light, medium and heavy recycled oils.

Suitable feeds may be previously treated or purified to remove sulfur, nitrogen or metals, such as by contact treatment in the presence of hydrogen. It is particularly preferred to use feedstocks with low nitrogen concentrations, and therefore feedstocks that have been subjected to hydrodenitrification are believed to be particularly suitable.

The conversion or cracking conditions used in the hydrocarbon conversion step of the present invention are such that the hydrocarbon feed is preheated or heat exchanged to a temperature of about 315-400°C before it is introduced into the cracking zone. Although partially obtained, preheating of the feedstock is not essential. Cracking and conversion conditions include:
from about 425°C to about 600°C, preferably from 460°C to
Temperatures of 560°C are included. Cracking conditions also include pressures from about 1 atmosphere to about 4 atmospheres or more, preferably from about 2 atmospheres to about 3 atmospheres. For fluidized catalyst systems, a catalyst/hydrocarbon weight ratio of about 3 to about 10 is generally preferred. The weight hourly space velocity of the hydrocarbons in the cracking zone preferably ranges from about 5 to 250 per hour. The so-called “spent” catalyst after contact with the hydrocarbons in the cracking zone
Preferably, the average amount of coke in the catalyst is from about 0.5% to about 2.5% by weight at the time the catalyst is passed through the regenerator. The exact coke concentration on the spent catalyst depends in part on the desired carbon concentration of the regenerated catalyst in the particular system, but also on the thermal balance of the particular system. The cracking, or reaction zone, may be of conventional design, including dilute-phase fluidized catalyst contact, riser-type entrained catalyst contact, dense bed fluidized catalyst contact, and countercurrent between the feed hydrocarbon and catalyst. Contact or a combination thereof can be used. Fluidization and entrainment of the catalyst can be aided using gases such as water vapor or nitrogen.

The catalyst regeneration zone used in embodiments of the invention may also be of any conventional design suitable for regeneration of cracking catalysts. The gaseous ambient atmosphere within a conventional cracking catalyst regeneration zone normally contains a mixture of gases, the concentrations of which vary depending on location within the regenerator. The concentration of the gas also varies depending on the coke concentration on the spent catalyst particles entering the regenerator and on the amount of molecular oxygen and water vapor introduced into the regenerator. Typically, the gaseous atmosphere within the regenerator includes 5-25% water vapor, varying amounts of oxygen, carbon monoxide, carbon dioxide, and nitrogen.
Regeneration zone temperatures of about 538°C to about 815°C are generally suitable, with temperatures of about 600°C to about 700°C being preferred. Preferably, regeneration is carried out in a dense phase fluidized bed of catalyst, where "dense phase" is defined as a density of 160 kg/m ³ or more.

An essential feature of the invention is the use of a crystalline solid having uniformly sized pore openings, or apertures, with a maximum diameter in the range of 5.5 to 7.0 Å units. Preferably, the crystalline solid is a zeolitic crystalline aluminosilicate or a crystalline silicate. Crystalline solids of this type are commonly referred to as having pore openings of "intermediate" size. Zeolitic crystalline aluminosilicates contain aluminum and silicon atoms, each of which is associated with four oxygen atoms, which combine with other aluminum and silicon atoms to form larger crystalline structures. do. The four oxygen atoms define a tetrahedron around the aluminum or silicon atom, with the aluminum and silicon atoms located in the center. The crystalline silicates that are suitable for use are also tetrahedrally organized, like the zeolitic aluminosilicates, but essentially no aluminum atoms are present in the crystal structure. The tetrahedra of these crystalline solids combine to form structural crystals with molecular-sized pores, openings, and cages or channels.
Crystalline silicates typically do not have cation exchange properties, whereas zeolitic aluminosilicates have
The above behavior is usually observed because of the electrical imbalance caused by the association of the aluminum atom and the four oxygen atoms. In the prior art, the pore openings or gaps in crystalline aminosilicates and crystalline silicates are
It is described as being defined by a certain number of tetrahedral "sides". Crystalline materials with pore sizes in the intermediate range usually have 10-sided pore sizes.
-sided apertures), whereas small pore zeolites, such as zeolite A, usually have 8-sided apertures, and large pore zeolites, such as zeolites X and Y
usually has 12 side gaps. Pore sizes with intermediate dimensions on the order of 5.5-7.0 Å are sufficient to allow paraffin and other relatively small diameter molecules to enter the crystalline solid cages relatively easily, but molecules with larger effective diameters, e.g. It is small enough to prevent dicyclics from penetrating into the crystal cages. It is also an essential feature of the invention that suitable crystalline solids have substantially uniform cages of "intermediate" maximum diameter, ie, units of 5.5 to 7.0 Å. In some cases, the crystal structure defines long channels rather than cages. In this case, the critical maximum dimension is that of the maximum diameter of the cross section of the channel. Cages with a diameter of 5.5-7.0 Å of suitable crystalline solids allow dehydrogenation of paraffin to occur, but prevent the formation of large coke-forming molecules within cages of intermediate dimensions. This is in contrast to the reactions that can take place within the large size cages present in crystalline aluminosilicates traditionally used in cracking catalysts, such as hydrogen or rare earth zeolite Y.

Suitable crystalline solids include, for example, zeolites.
These include ZSM-5, small pore mordenite, zeolite NU-1, a crystalline silicate named "silicalite", and other crystalline solids with characteristic crystal structures. Crystalline solids of this type can be used as synthesized or modified by known techniques such as ion exchange, acid leaching etc. to improve their porosity, acid strength and total acidity, their Catalytic hydrogen exchange and hydrogen transfer properties and their proportions of backbone atoms can also be varied. The products obtained by the process of the invention will vary depending on the characteristics of the particular crystalline solid employed. When so-called "silicalite" is used in the method of the present invention,
A relatively olefinic product is produced, whereas ZSM-5 type zeolites with low silica/alumina ratios
Despite having exactly the same crystal structure, relatively aromatic products tend to be obtained. Preferred suitable crystalline solids are zeolites having a crystal structure of type ZSM-5. Zeolites that fall into this category include, for example, in addition to ZSM-5.
ZSM-8 (see Dutch Patent Publication No. 7014807 and US Patent No. 3758403),
ZSM-11 (U.S. Patent Nos. 3709979 and 3804746)
Other zeolites such as ZSM-35 (see US Pat. Nos. 3,962,364, 3,965,210, 3,992,466 and 4,016,245) are included. Zeolite NU-1 (see U.S. Pat. No. 4,061,724) and "silicalite", a crystalline silicate described in Nature, Vol. 271, p. U.S. Patent No. 4,061,724 and
4073865 (please also refer to each specification) is also suitable.

Another essential feature of the invention is the use of catalytically active metals that have both strong dehydrogenation activity and strong oxidation activity. Active metals suitable for use in the practice of this invention include platinum, palladium,
Includes iridium, rhodium, osmium, ruthenium and copper. Platinum is particularly preferred since it has both a strong dehydrogenating activity and a particularly strong oxidizing activity. Like mixtures of platinum and palladium, platinum and iridium, platinum and rhodium, etc.
Combinations of two or more of the above active metals can also be used. In some cases, small amounts of other metals can have a promoting effect on the catalytic action of the inherently active metal. In this regard, chromium, zinc,
Mention may be made of tin, germanium, rhenium and lead. Accordingly, combinations such as platinum-tin, copper-chromium, platinum-rhenium and platinum-germanium are contemplated for use in the present invention. The promoter metal is preferably added to the original active metal in an amount such that the atomic ratio is between 0.01 and 1 per part of active metal.

Dehydrogenation-oxidized metal with activity is 5.5-7.0 Å
of the crystalline solid component, ie, the active metal is located on the inner surface of the crystal rather than on the outer surface of the crystal. Those skilled in the art will recognize that any practical method of disposing active metal within the interior of the crystal will inevitably result in a small proportion of the active metal being disposed on the external surface of the crystal. be. Although it is therefore desirable to minimize the amount of active metal present on the external surface of the crystal, it is already clear that in many cases it is unavoidable that some amount of active metal is present on the external surface of the crystal. It's calculated. The specified values for the amount of active metal in the catalyst refer only to the active metal present inside the crystals of the crystalline solid.

The active metal may be introduced into the interior of the crystalline solid by any conventional method. When using ion-exchangeable zeolitic crystalline aluminosilicate,
Cations, including active metals, can be ion-exchanged into the crystal structure of the zeolite using well-known techniques. To achieve a concentration that exceeds the exchange capacity, the active metal can be incorporated by other means, such as by an impregnation operation. When using crystalline silicates, the active metal can be impregnated within the silicate crystals while remaining essentially isolated from the silicate crystal structure. Various impregnation methods may be used, including pore-fill methods that do not result in too high a concentration of active metal on the external surface of the catalyst.
method) is preferred. It is also possible to incorporate a desired amount of metal into the crystal by combining methods for introducing the active metal into the interior of the crystal, for example by using both ion exchange and impregnation.

The amount of active metal contained within the crystals of the crystalline solid is calculated on the basis of the total particulate catalyst into which the crystalline solid containing the active metal is incorporated. In addition to the crystalline solid and the active metal, the catalyst particles preferably also include a matrix or binder component. The catalyst particles may also contain a second crystalline aluminosilicate component, such as an acidic zeolitic crystalline aluminosilicate component having large size pore openings and/or large size cages. can. Such large pore size zeolites are particularly suitable for acidic catalysis of some cracking reactions. Materials suitable for use as binders or matrices include, for example, silica, alumina, magnesia,
Included are porous inorganic oxides such as titania, natural and synthetic clays, silica-alumina, and others.
Inorganic oxide binders of this type are well known to those skilled in the art. Conventional zeolite catalysts include zeolite crystals associated with a matrix, ie, zeolite crystals dispersed or embedded in a matrix. This facilitates the shaping of catalyst particles.

The amount of active metal contained within the crystalline solids in the catalyst is from 0.01 to 1000 ppm by weight, based on the total weight of the catalyst. Preferably, the amount of active metal contained within the crystalline solid component is based on the weight of the catalyst.
It is 0.01 to 100ppm. In making the catalyst, a crystalline solid of intermediate pore size containing the active metal is mixed with a matrix or binder material or their precursors, and the mixture is then shaped by spray drying for use in a fluidized system. or, for moving bed systems, preferably by extrusion, pilling, etc. Generally, crystalline solids of intermediate pore size account for 0.05 to 50% by weight of the catalyst particles.
Good results are obtained when the Preferably, about 0.25 to 25% by weight of mesopore size crystalline solids are included in the catalyst particles. If large pore size zeolites are also included, the catalyst
Preferably, it is present at a concentration of ~30% by weight.

If the 5.5-7.0 Å crystalline solids used in catalysts have cation exchange properties, they can optionally exchange cations other than those of the active metal in the crystal structure, usually alkali metal cations. Can be substituted with synthetic cations. Preferred cations include, for example, known stabilizing cations such as rare earth metal cations, protons or proton precursors,
Examples include ammonium. If large pore or large cage crystalline aluminosilicate,
For example, when an X or Y type zeolite is incorporated into the catalyst particles along with a smaller pore zeolite of 5.5-7.0 Å, the cation exchange sites of the large pore zeolite may also contain rare earth, proton or proton precursors. Preferably, it is occupied by conventional activating or stabilizing cations such as.

Catalyst particles containing active metals can be advantageously used in any of several optional ways in cracking systems. In one approach, a single catalyst composition can be used as the sole catalyst agent in the particulate solids inventory circulating within the cracking system.
In such embodiments, the catalyst composition includes, in addition to the crystalline solid containing the active metal, a catalytically active,
Preferably, stable forms of large pore acidic crystalline aluminosilicate components are also included, such as X- or Y-type zeolites.

In another optional mode of use, the active metal-containing catalyst can be circulated through the cracking system as a physical mixture with other particulate solids. Other solids may be, for example, conventional zeolite-containing particulate cracking catalysts, or non-zeolitic crystalline or amorphous particulate cracking catalysts, such as acidic silica-alumina cogels, clay, etc. Other suitable particulate solids include alumina, or U.S. Pat. Nos. 4,071,436 and 4,115,249
Included are alumina-containing particles that can be used in cracking systems for the purpose of controlling sulfur oxides in catalyst regenerators, such as those disclosed in U.S. Pat. Alumina also has an intermediate pore size and can serve as a matrix or binder in conjunction with, or be incorporated into, metal-promoted zeolites.

In any of the modes utilized to carry out the process of the present invention, the total concentration of active metal present within the crystalline solids recycled to the purification system will exceed the weight of the total circulating particulate solids inventory in any individual unit. Calculated based on the standard, weight is 0.01 or more
Preferably maintained at 100 ppm. It is particularly preferred that the active metal is included at a concentration of 0.1 to 10 ppm by weight, based on the circulating particulate solids inventory. For example, catalyst particles containing active metals
5.5 to 5.5 in the catalyst itself when used as the sole component of the circulating particulate solids inventory.
The active metal concentration in the 7.0 Å crystalline solid is preferably between 0.01 and 100 ppm, particularly preferably between 0.1 and 10 ppm, based on the weight of the catalyst.
The active metal-containing catalyst is circulated as a physical mixture with other particulate solids, which may be, for example, conventional cracking catalyst particles or alumina particles (e.g. additive or co-catalyst).
catalyst)], the amount of active metal present within the crystals of the crystalline solid component and the concentration of active metal-containing particles in the system are such that the total particulate solids inventory is 5.5 to 7.0 Å crystals. Preferably, the total concentration of active metals present inside the solid is maintained at a level of 0.01 to 100 ppm, particularly preferably 0.1 to 10 ppm.

When burning off coke from active metal-containing crystalline solids in cracking catalyst regeneration units, it is best to make full use of the presence of prooxidizing active metals to achieve as complete an oxidation of coke and carbon monoxide as possible. preferable. The degree of complete combustion of coke during catalyst regeneration is characterized by the coke concentration on the regenerated catalyst. In the method of the invention, it is preferred that the coke be burned off from the catalyst such that the coke concentration on the regenerated catalyst particles is 0.2% by weight or less, particularly preferably 0.05% by weight or less. The degree of complete combustion of carbon monoxide during regeneration is characterized by the volumetric concentration ratio of carbon dioxide to carbon monoxide contained in the flue gas removed from the cracking catalyst regenerator. In the method of the present invention, the combustion of carbon monoxide in the cracking catalyst regenerator is controlled by an active metal such that the carbon dioxide/carbon monoxide volume ratio in the flue gas removed from the regenerator is at least 5. It is preferable to catalyze using. It is particularly preferred to provide sufficient carbon monoxide combustion in the regenerator to achieve a carbon dioxide/carbon monoxide ratio of at least 200 in the effluent gas.

To achieve the preferred relatively complete combustion of coke and carbon monoxide as described above, it is recommended to introduce molecular oxygen into the regenerator in excess of the stoichiometric amount of oxygen required for combustion. desirable. The amount of excess oxygen used in the regenerator is characterized by the oxygen concentration in the flue gas removed from the catalyst regenerator. When carrying out the method of the present invention,
Preferably, sufficient molecular oxygen is introduced into the regenerator to obtain an oxygen concentration of at least 0.3% by volume in the gaseous effluent from the regenerator. The carbon monoxide afterburn problem often experienced when using excess oxygen in conventional regenerators is overcome in the process of the present invention by the presence of active pro-oxidant metals in the regenerator. This will be avoided. Due to the oxidation catalytic activity of the metal, the combustion of carbon monoxide takes place rapidly in the presence of sufficient catalyst particles.
As a result, most of the heat of combustion of carbon monoxide is absorbed relatively uniformly by the catalyst particles, reducing the increase in flue gas temperature caused by additional combustion downstream of the catalyst bed.
It can be little or no.

The active metal-containing catalyst particles can be used in multiple stages of hydrocarbon conversion prior to regeneration. for example,
The circulating catalyst is first contacted with a first feed stream consisting of a relatively light hydrocarbon that lends itself to reforming type reactions, such as naphtha and lighter, and then a relatively light hydrocarbon that favors a cracking reaction. A second feed stream consisting of heavier hydrocarbons is contacted and finally regenerated. In the initial conversion stage, the light hydrocarbon feed is preferably a relatively low octane hydrocarbon, e.g. in the naphtha boiling range, such as n-pentane, n-hexane, n-
- heptane, etc., or relatively low octane hydrocarbon fractions, such as straight-run naphtha. The product obtained from this type of paraffin or naphtha upgrading stage can be combined with the product from the cracking stage or can be recovered separately. The products obtained from this type of first conversion stage typically contain naphtha boiling range olefins and aromatics, which have relatively high octane numbers.

As an alternative to multiple serial conversion stages, it is possible to carry out two or more separate conversion operations in parallel units, each utilizing a portion of the active metal-containing catalyst. A portion of the catalyst from each converter can be combined together and regenerated within a single regeneration zone. For example, a heavy hydrocarbon feed suitable for cracking-type conversion may be purified in a riser reactor unit while a lighter feed, originally suitable for dehydrogenation and aromatization-type conversion, may be purified in a second reactor. It is possible to purify the product in a riser reactor using a common product-catalyst separation zone and a common catalyst regeneration unit.

In addition to cracking reactions, other suitable conversion reactions that can be carried out using active metal-containing catalysts include dehydrogenation, polymerization, alkylation, cyclization, and the like. As used herein, the term "aromatization" refers to the reaction of aliphatic hydrocarbons to form hydrocarbons containing benzene rings. Examples include dehydrogenation of cyclohexane to form benzene, dehydrocyclization of n-heptane to form toluene, dehydrocyclodimerization of butane to form xylene, etc.

One advantage of two or more series conversion stages using a single catalyst recirculation stream is that one type of feed can contact the newly regenerated, relatively hot catalyst while It is possible to contact the catalyst particles, which are less active at low temperatures, with other types of feeds as appropriate. Such stepwise conversion steps can be achieved by serial purification in completely separate reaction columns or by converting different feeds at different points in a single reaction column, such as at different levels of a single riser reaction column. This can be achieved by introducing

Besides the light paraffinic and olefinic hydrocarbons or hydrocarbon fractions, other specific feeds are also advantageously treated in a separate conversion stage completely or partially separated from the main catalytic cracking stage. be able to. These include, for example, raffinates obtained from aromatic extraction operations, light oils with high paraffin content, slack waxes, foots oils, and the like. In general, it is advantageous for feeds suitable for conversion, separate from the original cracking feed, to be contacted with relatively hot catalysts in the absence of conventional catalytic cracking feedstocks.

Particularly desirable products from the original catalytic cracking process of this invention include products from paraffin dehydrogenation, such as _C3 to _C8 olefins, especially alkyl aromatics such as toluene, ethylbenzene, xylenes, and the like. These dehydrogenation and aromatization products have high octane numbers, which positively impacts the overall octane number of the catalytically cracked naphtha.

The examples described below illustrate the preparation and use of catalysts according to the process of the invention, along with a comparison with the preparation and use of conventional cracking catalysts.

Example 1 To demonstrate the effectiveness of a typical FCC catalyst containing a calcined rare earth Y-sieve with the same activity as a commercially available catalyst:
First, a comparative catalyst was prepared. 29 pounds of water in a 5-gallon container stirred in a Cowles dissolver
Kg), 900g of γ-alumina, and
Amorphous silica ground to an average particle size of 15 microns
Added 5 pounds of alumina. To this stirred mixture was added 325 ml of concentrated nitric acid. The mixture was then heated to 130°C (approximately 54.4°C) and stirred for 45 minutes. After 45 minutes, 527 g of calcined rare earth exchanged Y-zeolite obtained from Union Carbide Corporation was added.
The resulting mixture was heated to an inlet temperature of 375°C and 130°C.
Storke, New Jersey, with an outlet temperature of
Spray dried using a two-component nozzle in a Bowen Engineering of Somerville spray dryer. The finished catalyst had a water pore volume of 0.29 cc/g and a nitrogen surface area of 190 m ² /g. This composition will be referred to as Catalyst A hereafter.

Example 2 Example 2 describes the preparation of a second comparative catalyst containing REY-sieves and H-ZSM zeolite. The H-ZSM zeolite of this catalyst does not have active metals incorporated into its crystal structure. This second comparative catalyst was made using essentially the same procedure as Catalyst A, except for the simple changes described below:
Along with the addition of zeolite, crystalline aluminosilicate of type H-ZSM was added in an amount to give 2.5% by weight of the finished catalyst. The finished catalysts had almost unchanged surface area and pore volume. This composition is
Hereinafter, it will be referred to as catalyst B.

EXAMPLE 3 Instead of using H-ZSM zeolite, a third catalyst having the requisite properties for use in the process of the invention was added in a quantity sufficient to present 2.5% by weight of Pt-ZSM zeolite in the finished catalyst. Catalyst B was prepared in the same manner as in the preparation of catalyst B, except that a platinum-exchanged ZSM-type zeolite containing about 0.36% by weight of platinum was added. This catalyst contained 90 ppm platinum as a finished catalyst. It was named catalyst C. The physical properties of Catalyst C were the same as Catalyst A and Catalyst B.

Example 4 Catalytic cracking properties of Catalyst A were tested in a fluidized circulation test device. In this test, the catalyst is placed in a vessel and heated to 925°C, and the feedstock, light East Texas gas oil (LETGO), is introduced into the bottom of the vessel. The total feed weight was 1/5 of the original catalyst charge weight. The product from the test was collected and thoroughly stripped of spent catalyst using nitrogen before analysis. The spent catalyst was then regenerated with oxygen and the carbon dioxide was collected and analyzed using known analytical methods. The four cycles were then repeated for a total of five cycles. Before introducing the catalyst particles into the equipment, the catalyst particles were incubated at 1400 〓 (approximately 760
℃) for 6 hours. This steaming method provides the catalyst with the same activity found in equilibrium catalysts in commercial FCC equipment. As an average of 5 cycles, Catalyst A produced 66.32% by volume of 430〓 (approx.
221.1°C) - conversion, 3.40% by weight coke (based on fresh feed) and 0.10% by weight hydrogen. The gasoline yield was 45.38% by weight. The octane number (single taste) of the gasoline obtained with catalyst A was 85.5 according to the research method, and the octane number (single taste) according to the motor method was 78.1. The analysis results of this gasoline were as follows.

Weight % Olefinic 7 Aromatic 32 Paraffinic and Naphthenic 61 These results are essentially what would be expected by one skilled in the art and are representative of current commercial FCC catalysts.

Example 5 Catalyst B was tested in the same manner as Catalyst A. In this test, catalyst B gave a conversion of 56.32 LV%. The degree of reduction was compared with that of catalyst A. Based on the feed, coke was 2.70% by weight and hydrogen was 0.13% by weight. Regarding hydrogen, it increased slightly compared to catalyst A. The yield of gasoline is
It was 35.77% by weight based on fresh feed.
The octane number of this gasoline is 85.6 according to the research method.
(single) and 78.2 (single) using the motor method. Analysis of the gasoline showed 14% olefins, 33% aromatics, and 53% paraffins and naphthenes. Catalyst B had a lower gasoline yield than Catalyst A, but the octane number of the gasoline was higher mainly due to the increased olefin content. This analysis is consistent with a substantial gain in octane for the Research method, but only a minimal gain in octane for the Motor method. This is because olefins, as a class, exhibit higher research octane values than paraffins and naphthenes, but comparable (or slightly higher) motor octane values. Therefore, a high olefin content significantly improves the research octane number, but not the motor octane number. Those skilled in the art will recognize that motor method octane ratings are more relevant to drivability than research method octane ratings. The reduction in C ₅ + gasoline yield is typical of the results of cracking with catalysts containing ZSM-type zeolite components.

Example 6 In this example, Catalyst C according to the invention was used to crack a heavy hydrocarbon feed. Under the same test conditions as in Example 4, for catalyst C
A conversion of 60.98 LV%, 3.22 wt% coke and 0.15 wt% hydrogen was obtained. The gasoline yield was 37.53%. The yield of this gasoline is amazing. By exchanging platinum into ZSM,
The gasoline yield was increased over Catalyst B, which is a ZSM-type catalyst. This is an unexpected and very advantageous effect obtained by including platinum in the ZSM-type zeolite. Additionally, the use of Catalyst C results in a slight increase in coke and hydrogen, which is surprisingly modest compared to the current patent literature teachings about the deleterious effects of adding platinum to cracking catalysts. it is conceivable that. According to the analysis results of gasoline obtained using catalyst C,
8% olefins, 38% aromatics, and 54% paraffins and naphthenes. Since aromatic compounds as a class have high octane numbers for research and high octane numbers for motor methods, higher aromatics would be expected to show benefits in both research and motor octane numbers. The measured octane number is
The score was 87.0 for the research method and 78.8 for the motor method.
This shows that the octane number of gasoline can be improved by platinum exchange with ZSM-type zeolite mainly due to the production of aromatic compounds. This should be compared with the case of the gasoline with catalyst B in the experiment described in Example 5, where the octane number improved almost entirely due to the formation of olefins. In conclusion, it can be said that platinum performs an advantageous function in the implementation of the hydrocarbon conversion of the present invention by increasing the gasoline yield compared to the catalyst containing sieves of the H-ZSM type (catalyst B). Catalyst B itself is superior to Catalyst A, which is a conventional zeolite-type catalyst, but Catalyst B has an even better octane number in both the Research method and the Motor method than Catalyst B.
obtained by.

EXAMPLE 7 Measurements of CO conversion activity of catalysts A-C were made on spent portions of the catalysts after use in the experiments described in Examples 4-6 using a 1- _inch diameter (approx. 2.54 cm) in a floor of 1250 mm (approx.
676.7°C). Catalyst C was found to have substantial CO→CO ₂ conversion activity.

The embodiments described below represent preferred modes of carrying out the method of the invention.

Embodiments Zeolite crystals are formed from an initial aqueous reaction mixture containing ethylene diamine, sodium silicate solution, sodium aluminate, sodium chloride, and hydrochloric acid. The composition of this initial reaction mixture, based on moles of oxide, is _ED2O10.56 : _Na2O .
Al ₂ O ₃ 5.44: SiO ₂ 80: H ₂ O 42: NaCl 83.9.
"ED ₂ O" used here represents an oxide of ethylenediamine. Sodium chloride and hydrochloric acid are used in the initial mixture to maintain proper PH and ionic strength levels. The gel obtained from this mixture is homogenized and aged for approximately 2 months at an ambient temperature of about 25°C. After aging, the gel is autoclaved
Maintain temperature at 150°C for 8 days. At the end of the 8 day period, the zeolite crystals are filtered from the resulting solution, washed free of chloride ions and dried for 17 hours at 110° C. in a nitrogen atmosphere. As a result of powder X-ray diffraction analysis, U.S. Patent No.
ZSM, as disclosed in specification no. 3702886
A ZSM-type figure unique to type-5 zeolite was shown. This zeolite crystal is observed to have a uniform pore opening of about 6.5 Å and a uniform cage with a maximum diameter of about 6.5 Å. Zeolite crystals,
The zeolite crystal is brought into contact with an aqueous solution of a platinum compound containing platinum in the form of a cation to impregnate the crystal structure of the zeolite crystal with platinum to perform ion exchange. The resulting active metal-containing zeolite crystals are then calcined and mixed with aqueous silica-alumina hydrogel and hydrogen form zeolite Y crystals. On an anhydrous basis, this mixture contains 2.5% by weight of platinum-containing ZSM-5 zeolite;
〓15% by weight of calcined rare earth exchanged Y-type zeolite, 57.5% by weight of amorphous silica-alumina and 25% by weight of alumina
Including weight %. The mixture is then spray dried to form catalyst particles with a particle size of 50-100 microns. The catalyst particles thus formed contain 75 ppm by weight of platinum, calculated as an element. Using a combination of riser and floor type cracking,
Conduct a cracking test within the FCC equipment. For comparison, a conventional FCC containing 15% by weight of rare earth exchanged zeolite Y in a silica-alumina matrix
The catalyst is first applied to the device and the baseline
Establishing a bond. A raw material light oil having a boiling point range of 325 to 525°C is used. The decomposition temperature is 500°C and the catalyst/oil ratio is 7. The spent catalyst passed to the regenerator contains 0.8% by weight of coke. Regenerate the spent catalyst at a temperature of 650℃. The carbon dioxide/carbon monoxide ratio in the flue gas from the catalyst regenerator is approximately 2 by volume, and the oxygen concentration in the flue gas is approximately 2% by volume. The carbon concentration of the regenerated catalyst is approximately
It is 0.08% by weight. All naphtha products (24-220℃)
The research method octane number is determined to be approximately 91. Total feed conversion was approximately 70% by weight with product 15.0%
The weight percent is _C2 - _C4 olefin. In accordance with the present invention, the conventional catalyst is then replaced with a platinum-containing intermediate pore size zeolite catalyst in the same FCC apparatus using the same feedstock and the same cracking conditions. Maintain catalyst regenerator temperature at 677°C.
Carbon dioxide in flue gas from regenerator/
The volume ratio of carbon monoxide is recognized to be approximately 200,
As a result of introducing a sufficient excess of oxygen into the regenerator, it is observed that the oxygen concentration in the flue gas is approximately 2% by volume. The amount of coke on the spent catalyst is approximately 0.9% by weight
, and the carbon concentration on the regenerated catalyst is found to be approximately 0.05% by weight. The research method octane rating for all naphtha products is 93. The total conversion obtained using the catalyst of the present invention is about 67% by weight, with 18.0% by weight of the product being _C2 - _C4 olefins.

Embodiments Zeolite crystals are formed using the same procedure as described in the embodiments. The zeolite crystals are impregnated with anionic form of platinum from an aqueous chloroplatinic acid solution using a pore-filling impregnation method. The active metal-containing zeolite crystals are then mixed with hydrolyzed clay and the resulting mixture is spray-dried to a diameter of 50 mm.
Forms particles of ~100 microns. The particles obtained contain 20 ppm by weight of platinum, calculated as an element. The same conventional method as in the embodiment
The cracking test is carried out again in the FCC equipment, with the same feed and under the same operating conditions. First, the conventional RE-Y catalyst is used alone to obtain the same conventional results as in the embodiment. Next, according to the present invention,
Fifteen weight percent of the conventional RE-Y catalyst is removed from circulation within the FCC unit and replaced with an equal amount of platinum impregnated mesoporous zeolite catalyst particles. Maintain the temperature inside the catalyst regenerator at 677°C. The volume ratio of carbon dioxide/carbon monoxide in the flue gas from the regenerator was found to be approximately 150, and as a result of introducing a sufficient excess of oxygen into the regenerator, the concentration of molecular oxygen in the flue gas is found to be approximately 2% by volume. The amount of coke on the spent catalyst was determined to be approximately 0.9% by weight;
It is observed that the concentration of carbon on the regenerated catalyst is about 0.08% by weight. The research method octane rating for all naphtha products is 93. A total conversion of about 68% by weight is obtained, with 16% by weight of the product being _C2 - _C4 olefins.

Although preferred embodiments of the present invention have been described above, the broad scope of the present invention as well as various modifications of the present invention,
Equivalent methods and modifications will be apparent to those skilled in the art. The claims are intended to cover these variations, modifications and equivalents.

Claims (1)

[Scope of Claims] 1. A method for converting a feedstock hydrocarbon having a normal boiling point higher than 220°C, comprising: (a) a crystalline solid selected from zeolitic crystalline aluminosilicate and crystalline silicate; placed inside a solid crystal,
0.01 or more by weight of an active metal or a compound of an active metal selected from platinum, palladium, iridium, rhodium, osmium, ruthenium and copper, calculated as an element based on the catalyst
1000 ppm of particulate solid catalyst is circulated between the reaction zone and the catalyst regeneration zone, wherein the crystalline structure of the crystalline solid is substantially uniform pores having a maximum diameter on the order of 5.5 to 7.0 Å. (b) defining an opening and a substantially uniform cage having a maximum cage dimension in the range of 5.5 to 7.0 Å, thereby limiting contact between the feedstock hydrocarbon and the active metal; contacting the feedstock hydrocarbon with the catalyst in the reaction zone under cracking conditions including the absence of added molecular hydrogen;
forming cracked hydrocarbons having a normal boiling point below °C and depositing coke on the particulate solids and contacting the active metals contained in the crystalline solids in the reaction zone; dehydrogenating and aromatizing aliphatic components in the feedstock hydrocarbon and the cracked hydrocarbon to form olefins and aromatic compounds; and (c) in the regeneration zone under catalyst regeneration conditions. burning off coke from the catalyst using molecular oxygen to form carbon monoxide; and combusting the carbon monoxide with molecular oxygen in contact with the active metal contained in the crystalline solid. How to characterize it. 2. The method according to 1 above, wherein the active metal is platinum. 3. The crystalline solid is a zeolitic crystalline aluminosilicate, and at least a portion of the active metal is located within the aluminosilicate as a cation occupying an ion-exchangeable cation site in the crystal structure of the aluminosilicate. The method according to 1 above. 4. The method according to 1 above, wherein at least a portion of the active metal is introduced into the interior of the crystalline solid by impregnation. 5. The method according to 1 above, wherein the crystalline solid has a ZSM-5 type crystal structure. 6. The method of claim 1, wherein sufficient carbon monoxide is combusted in the catalyst regeneration zone to provide a carbon dioxide/carbon monoxide volume ratio of at least 5 in the gas removed from the regeneration zone. 7. The catalyst contains 2.5-25% by weight of crystalline solids,
2. The method of claim 1, further comprising a porous inorganic oxide matrix. 8. The method according to 7 above, wherein the catalyst further comprises a crystalline aluminosilicate selected from zeolite X or zeolite Y in hydrogen form and zeolite X or zeolite Y in rare earth form. 9. The method of claim 1, further comprising contacting at least a portion of the catalyst, after burning off the coke from the catalyst in the regeneration zone, with at least one hydrocarbon having a normal boiling point below 220°C. Method. 10. Circulating the catalyst between the reaction zone and the regeneration zone as a physical mixture with a particulate solid comprising alumina and at least one component selected from zeolitic crystalline aluminosilicates having a haujasite crystal structure. The method described in 1.