Process for the preparation of catalysts and for cracking mineral oil fractions

The present invention relates to a process for preparing catalysts or catalyst additives for use in petroleum cracking, wherein the suspension consists of a catalytically active component, preferably H-ZSM-5 zeolite, as well as aluminum hydroxide and / or one or more aluminum hydroxy compounds. , and / or one or more other binders and, if necessary, kaolin (s) as well as one or more fluxes, mixing and / or grinding and processing by spray drying and heat treatment. The invention also relates to a modification of the silicic acid of formula (I):

H4 + y._z[(SiO4 / 2) xy (AlO4 / 2) y (SiO3 / 2O) 4._z(AlO3 / 2) z] (I) wherein y is less than 1, z is less than 1, ox is 0, 4, 10 or 16-18 prepared by ion exchange of aluminum-containing sodium silicate strains using petroleum fractions for cracking or for the production of olefins with branched chains.

Conversion of high-boiling oil fractions into low-boiling fractions, which are generally suitable as fuel for gasoline and diesel engines, a process known as "liquid catalytic cracking (SKK)", has been economically viable for several decades in petrochemicals. the most important and volume-based process. Zeolites, especially of the phoazite type, are converted to their H-form [CJ Plank and EJ Rosinski, Chem. Eng. Prog. Symp. Ser. 73, 26 (1967)] as an important technological advance in the use of active components in SKK catalysis.

In recent years, a number of processes have been patented, the novelty characteristics of which include the use of one or more other types of zeolites, typically H-ZSM-5, in combination with foyazite-type zeolites used as active components in SKK catalysis to obtain cracked products with suitable octane number compositions. and environmental effects of combustion products. The methods discussed in the patent literature can be divided into two groups:

1. The general characteristics of the first group of processes are that one or more additives containing other catalytically active, liquid-formable, particulate-component components are added to the reactor apart from the phosazite-type catalyst.

2. According to the second group of methods, two or more catalytically active zeolite components are added to the SKK catalyst particles in the required ratios; the active components in the particles are in a discrete, homogeneously distributed crystallite form.

The first group of catalysts, which can be added in any desired ratio, gives greater flexibility to the SKK process, as this process can be tailored to the requirements of the product composition and the raw materials to be processed, choosing the correct ratios.

According to European patent no. 229609, the catalyst was prepared using a clay mineral matrix bonded to a colloidal alumina and / or silica solution and finely dispersed ZSM-5 zeolite. Combined use of this catalyst with a conventional SKK catalyst allows the conversion of high boiling point oil fractions into gasoline high octane fractions.

According to U.S. Patent No. 4309279, an increase in olefin yield of 14.4 to 21% (by volume) and an increase in experimental octane number of the gasoline fraction from 89.2 to

The 91.2 SKK process can be achieved mainly at the expense of the gasoline fraction if the active component is used in a 0.5% (w / w) additive of a ZSM-5 zeolite in combination with a conventional SKK catalyst.

In European patent no. 156490 also describes a process which essentially involves the use of a mixture of two liquid catalysts as a SKK catalyst. One component of the mixture is a conventional SKK catalyst containing phosazite, and the second is a liquid catalyst consisting of an amorphous aluminum silicate phase with HZSM-5 zeolite in an amount of 0.1 to 20% by weight. The proportion of the component containing the H-ZSM-5 zeolite may vary between 0.1 and 50% (w / w). Although the addition of a catalyst containing 2% (w / w) of zeolite pretreated with steam at 788 ° C, the C3 / C4 fraction and the olefinic product content and the octane yield of the small gasoline fraction obtained are practically unaffected by the addition of that catalyst. the quantity of fresh additive not previously treated with steam.

Similarly, European patent no. The essence of 600686 is that a mixture consisting of SKK catalyst containing 12.24% (w / w) of ultra-stabilized Y-zeolite and a liquefying catalyst additive having a boiling point is used for cracking high-boiling fractions, such as diesel oil vacuum distillate. 25-57.5% by weight of H-ZSM zeolite. Substantial increases in the olefinic fraction of the product, e.g., from 16% to 36%, can be achieved by adding a catalyst additive up to 60% to conventional SKK catalysts.

U.S. Pat. No. 3758403 is directed to a SKK catalyst prepared by incorporation of coarse zeolite, preferably in the form of fine porosity, in the form of fine crystallites in the form of fine crystallites of the phosazite type, together with medium zeolite, preferably of the Pentasil grade, and its use in high octane gasoline.

U.S. Pat. No. 5077253 describes a SKK catalyst which has beneficial properties, with a high ability to bind heavy metals. This catalyst has a high concentration of particulate zeolite, preferably dealuminized Y-zeolite, and a zeolite having cracking and isomerization activity, preferably H-ZSM-5, and a zeolitic component, preferably Ga-ZSM-5, catalyzing aromatization, lower particle shell concentration and higher particle concentration. at the core.

In European patent no. No. 489324 describes a process for the selective production of olefinic and aromatic compounds and high octane gasoline; this process involves the simultaneous use of omega- and Y-zeolite as a catalyst.

The use of phosazite and ZSM-5 zeolites as catalysts for SKK is described in U.S. Pat. 3894934, in which both zeolites are homogeneously distributed in a matrix or they form the active component of separate catalysts. Both catalysts having one of the active components give effect separately in the two reaction zones separated from each other in the cracking reactor.

In the methods described in the patent literature relating to the preparation of SKK catalysts and additives, spherical or nearly spherical catalyst particles of the required size can be obtained by spray drying aqueous suspensions containing the catalytically active zeolitic component (s) as well as one or more suitable excipients. Typically, fillers are kaolinite or other clay minerals in amounts ranging from 20 to 70% by weight based on the total solids weight (see, for example, U.S. Patent Nos. 3142057, 3867308 and 4086187). Suitable binders are usually aluminum hydroxy compounds (see, for example, U.S. Patent Nos. 4458023 and Canadian Patent No. 967136) and silica hydrosols (see, e.g., U.S. Pat. 3972835 and 3867308), used alone or in combination with selected silica or alumina in a wide range, typically 5 to 50%, based on the total weight of solids (see, e.g., U.S. Patents 3,957,689 and 4,493,902). The weight ratio of solids to water in the spray emulsion is limited, on the one hand, by the viscosity, which determines sprayability, and, on the other, by the particle diameter of the catalyst produced, which must be in the range of 20-100 µm. The water content of the spray emulsion is usually 20-60% by weight. The spray-dried product is calcined at elevated temperatures (300-800 ° C) for several hours, for example according to U.S. Pat. 4677084 and 4493902; 3001800 and 3317946 for obtaining catalysts with suitable mechanical properties, in particular with higher resistance to degradation.

A general characteristic of the catalysts and their applications described so far is that these catalysts significantly increase the yield of C3-C5 olefins at the expense of the gasoline fraction and the octane number of the gasoline fraction obtained in the SKK process. However, the patents described above do not mention the relationship between the individual butenes and the pentenes in the respective fractions. Currently, isobutene is one of the most desirable petrochemicals because, in addition to methanol, it is used as a starting material for the industrial production of methyl t-butyl ether (MTBE), an additive that increases octane in unleaded petrol. Thus, it is desirable to enhance the isobutene selectivity of the SKK process by promoting skeletal isomerization of other butenes.

In our research, it has been found that aluminum-containing silicic acid modifications of Formula (I) wherein y is less than 1, z is less than 1, and x is 0, 4, 10, or 16-18 (particularly isostructured silicic acid modifications, wherein x is 10 obtained from magnesium ion exchange) can, under appropriate reaction conditions, catalyze the isomerization of short-chain olefins, especially n-butenes, to branched-chain olefins having a quaternary carbon atom.

It has now been found (in experiments conducted on a standardized "Microactivity Assay (MAT)") that the yield of isobutene is greatly increased at the expense of other butenes (that is, the concentration of individual butenes in the butene fraction is compositions containing a modification of the silicic acid of formula (I), ⁵ LT 4214 B catalyzed isomerization of short chain olefins, mixed with 230% (w / w) conventional SKK catalyst.

Thus, the present invention relates to the preparation of catalysts or catalyst additives using a suspension comprising a catalytically active component, preferably H-ZSM-5 zeolite, and aluminum hydroxide and / or one or more aluminum hydroxide compounds and / or one or more other binders and such as mixing and / or grinding kaolin (kaolinite) and also one or more liquefying agents, spray drying and heat treatment. According to the present invention, one or more alumina-containing silicic acid modifications of formula (I) are used in place of kaolin (kaolinite) or a portion thereof used as a filler, wherein y is less than 1, z is less than 1, ox is 0 , 4.10 or 16-18, preferably 10.

In addition, the present invention also relates to a catalyst or catalyst additive having a silicic acid modification of formula (I) wherein y is less than 1, z is less than 1, ox is 0, 4, 10 or 16-18. by ion-exchange of aluminum-containing sodium silicate.

The present invention also relates to the use of this catalyst or catalyst additive to obtain cracked petroleum fractions or branched olefins, in particular isobutene.

We have found that the mechanical properties of the catalyst particles, in particular their resistance to degradation, are greatly improved when the kaolinite used as a filler or a portion thereof is replaced by a modification of the silicic acid of the invention. It has been found suitable to use equal amounts of the silicic acid and kaolinite of the invention, each of which is present in an amount of 25%, based on the solids content of the suspension.

The main advantages of the process and the catalyst or catalyst additive according to the present invention are as follows:

(a) in the butene fraction of cracked products, the amount of isobutene used in the production of methyl butyl ether, which is used to increase the octane number, is increased;

(b) the products have improved mechanical properties such as resistance to breakage;

c) The catalyst and catalyst additive of the present invention can be readily prepared using conventional technical equipment.

The preparation of a catalyst or catalyst additive according to the present invention and their use as a SKK catalyst or catalyst additive are illustrated by the following examples, which do not limit the scope of the invention.

example

The air-dried H-ZSM-5 zeolite, kaolin, and crystalline silica modification having a layered structure (produced in the case of a catalyst additive from magadite isomorphically substituted with aluminum and designated by number 2 in Table 1) were suspended in the weight ratio in Table 1 at such in an amount of 60% (w / w) dry weight of aluminum hydroxychloride solution. The slurry was milled in a ball mill for 40 hours to give 95% (w / w) solids of less than 10 µm in size. The viscosity of the suspension, measured with a rotary viscometer, was found to be 2500 mPa.s at 3 s'¹, and 200 mPa.s at 1000 s'¹. The suspension was dried in a spray dryer at an inlet temperature of 300 ° C and an outlet temperature of 140 ° C. The operating characteristics of the spray disk were chosen so that the dried product had spherical or near-spherical particles between 20 and 100 µm in diameter. Subsequently, the product was spread on drying trays and calcined in an electric furnace at 550 ° C for 10 hours to obtain adequate resistance to decomposition.

The degradation values ​​of the SKK catalyst additive obtained in this way are shown in Table 1.

table

<td></td><td>Annex 1 the usual composition</td><td>Annex 2 composition according to the invention</td>

<td>H-ZSM-5</td><td>25% by weight</td><td>25% by weight</td>

<td>Kaolin</td><td>55% by weight</td><td>30% by weight</td>

<td>Silicic acid¹</td><td> ...</td><td>25% by weight</td>

<td>Aluminum hydroxide</td><td> 20 ^c/ ((by weight)</td><td>20% (by weight)</td>

<td>Decomposition²</td><td>12.5% ​​w / w</td><td> 6,0 ^CA (by weight)</td>

Ί

Devison decay rate³ 2,85 0,87

Jersey indicator⁴ 0,14 0,002 ¹ Crystalline silicic acid having a layered structure derived from aluminum-containing magadite by ion exchange.

² Particle size of particles less than 40 µm in diameter after grinding a screened fraction above 40 µm for 30 minutes under standardized conditions.

³ Determined by U.S. Pat. 3957689.

⁴ Determined by U.S. Pat. 3957689 sample of material disrupted during the second 10 minute period

Addition 1 of the SKK catalyst, containing the usual composition obtained according to Example 1, and the additive 2, containing the composition according to the invention, were mixed with 5% (w / w) of a commercially available SKK catalyst containing ultra-stabilized Y zeolite substituted by rare earth metals. ion and then stored in a vapor atmosphere (1 bar) at 750 ° C for 6 hours. The activity and selectivity of the catalyst mixtures in the catalytic cracking process were investigated by the MAT test detailed in the Oil and Gas Journal (6063, November 23), accurately maintaining the experimental parameters and test equipment used. The results relevant to the present invention are given in Table 2.

table additive usual composition additive composition according to the invention

<td>Conversion, 7c. by mass</td><td> 72,2</td><td> 72,2</td>

<td>(C3-C4) olefins,% yield by weight</td><td> 14,7</td><td> 14,8</td>

<td>C₄ olefins,% by weight</td><td> 8,1</td><td> 8,0</td>

<td>Coke,% by weight</td><td> 3,6</td><td> 3,7</td>

<td>Petrol, yield 7c by weight</td><td> 45</td><td> 45</td>

<td>Isobutene / all butenes</td><td> 30,5</td><td> 33,7</td>

Motor Octane Number (MON) 81.0 81.2

Experimental octane number (RON) 94.3 94.5

It can be noted that at the same conversion and coke formation rates, the use of the catalyst of the present invention yields more isobutene than the conventional catalyst.