DD151568A3 - PREPARATION OF ALUMINUM OXIDE-CONTAINING CATALYSTS FOR N-PARAFFINIZERIZATION - Google Patents

Abstract

The invention relates to the preparation of alumina-containing y-zeolite catalysts for the conversion of n-paraffinic hydrocarbons in iso-paraffinic hydrocarbons to improve the octane number. It was the object to find such a deformation method for y-zeolite catalyst masses, are obtained with the mechanically stable and specific light moldings of any shape and high macroporosity. In a first stage, a boehmite-containing alumina hydrogel having a basic salt-forming acid in the molar ratio of acidity / hydrogel of 0.05 to 0.20 at room temperature in a low dispersibility Hydrosol I, in the second of this Hydrosol I by heating to 323 to 423 K in a Hydrosol II is transferred and heated until the desired degree of dispersity is reached. The hydrosol II is optionally shaped in combination with other components with the addition of finely ground ion-exchanged Y zeolite under reaction with a coagulant to moldings, and further processed in a known manner.

Description

-Ί-

VEB Leuna-Werke Merseburg, July 3, 1979

"Walter Ulbricht" DCP / Sch

LP 7921 Title of the invention

Preparation of Alumina-Containing Catalysts for !! Paraffin Isomerization

Field of application of the invention

The invention relates to a process for the preparation of highly porous and mechanically solid alumina-containing Y zeolite catalysts for the isomerization of low-boiling n-paraffins or coal mixtures containing such.

Characteristic of the known technical solutions

As a catalyst for the isomerization of low-boiling n-paraffins or hydrocarbon mixtures containing such ion-Etenau.au.t., noble metal-containing Y zeolites are used. These catalysts can be used in a wide variety of geometrical forms, whereby, inter alia, the geometry of the technical reactor used determines the suitability of certain catalyst moldings. If it is possible to ensure a sufficiently high catalytic activity, the specific bulk density is thus low.

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as the catalysts contain very expensive constituents. On the other hand, the catalyst moldings must be able to cope with the mechanical stresses of practical operation.

For the preparation of zeolite catalyst moldings "several methods have already been proposed, as well as mordenite, erionite, X and A zeolites were used as zeolites." Zeolithformlinge should by tabletting without binder (DE-AS 1 667 314) or by tableting after mixing the zeolite powder with suitable binders (DE-AS 1 249 834, DD-PS 130 531) or by extrusion into solid billets (DD-PS 96 642, DD-PS 116 008) or by agglomeration to Agglomerierkugeln (DD-PS 100 403) to be produced · another solution to the problem of deformation of mordenites is the common V _e rtropfung of suspensions of mordenite and a binder in an organic agent and then curing (DE-AS 1,215,660, DE-AS 1,259,853, DE-AS 1,442,856 DE-AS 1 442 858, DE-AS 1 442 859, DE-AS 1 442 880, DE-AS 1 442 882, DE-AS 1 545 283, DE-AS 1 545 418).

The binders used are predominantly aluminum oxides or oxide hydrates and / or aluminosilicates (DD-PS 116 008, DE-AS 1 946 187) or partially hydrolyzed aluminum salts (SU-PS 484 183).

The Hauptnactteil the previously known methods for the deformation of Ϊ zeolite catalyst masses is that either the moldings produced by the deformation method Although the required for a technical application high mechanical strength but at the same time have a high bulk density, (78OO g / l), which uneconomically high Consumption of expensive feedstocks (zeolite, precious metal) causes or that a low bulk density (z600 g / l) is achieved, but the too-high-Saxon strength makes technical use difficult or impossible, »The application of the Mordenite described method of deformation by dripping is not yet known for Y zeolites

- 3 - «; ι ο ο * ♦ ο.

In the DD-.WP 136 344- is a method

for the preparation of mechanically stable Y-zeolite catalyst moldings which, by means of a complicated technology when using binder mixtures and a specific thermal treatment, enables the preparation of mechanically stable hollowware moldings with a bulk density of only 56O to 570 g / l *

Object of the invention

The object of the invention is a simple process for the preparation of mechanically stable Y-zeolite catalyst moldings with low specific bulk density, which causes the catalytic properties of the Y-ze & ithkatalysatassen for u-paraffin isomerization without reduction to effect »The Y-zeolite catalyst moldings should be easy to produce and the Forming mold can be easily adapted to the respective application «Pur the deformation process should be easy to produce ^ Cheap and universal ^ usable binders can be used»

Principle of the _Er-making

The object of the invention is to prepare such alumina hydrosols as a mixed component by conversion of böhmithaltigen Alurniniumoxid hydrogels of any provenance, with which ea is possible to deform Y zeolite catalyst masses to mechanically stable, specific light forms of any shape and high macroporosity.

According to the invention, the object is achieved by carrying out a peptization of an alumina hydrogel two stages, wherein in the first stage, a predominantly boehmite hydrogel containing a basic salts acid forming in the molar ratio acid / hydrogel of 0 ^ .05 to 0.20 at Room temperature in. A hydrosol I low dispersity and viscosity converts and in the second stage, the hydrosol I

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by heating to temperatures of 323 to 423 K in a hydrosol II and heated until the desired degree of dispersity is reached, the hydrosol II optionally in combination with other components with the addition of finely ground ion-exchanged Y-zeolite under reaction with a coagulant z \ x forms moldings which are thermally post-treated and processed in a known manner. The use of an alumina hydrogel, which has been precipitated above the pH of 7.5, in the form of a moist cake or in the form of finely ground, dried aluminum trihydroxide or mixtures of filter cake and dried products, is particularly favorable

As favorable, an adjustment of the water content of the hydrosol I formed in the first stage of 60 to 90 mass%, "Advantageously, used as the basic salt-forming acids nitric acid, hydrogen halides or carboxylic acids", The desired high degree of dispersity of the hydrosol II can by It is possible to form mixtures of hydrosol II and ion-exchanged Y zeolite as well as of hydrosol I, hydrosol II and ion-exchanged Y zeolite, the content of which can be achieved for a period of 0.1 to 24 h Y zeolite may be from 1 to even 80 % of the solids content of the total mixture.

For the process according to the invention, it is possible to use Y zeolites which have been ion-exchanged by a wide variety of methods and ions, that is, the ion exchange in one or more stages with or without heat treatment between optionally several exchange cycles both in solutions and in melts The Y zeolite catalyst moldings prepared according to the invention have such good mechanical properties that it is also possible to carry out further ion exchange operations on the finished molds.

The following exemplary embodiments are intended to explain the invention in more detail.

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Exemplary embodiments

example 1

10.3 kg Ka Y-zeolite having a siop / Al ^ O ^ molar ratio of 4.9 to 17.5 1 3.85 GaClg η solution and η 3.67 11.5 1 Mg (New) 2- After filtration and washing, the filter cake was dried at 385 K and annealed at 800 K for 12 h. The ground product was treated with 10 l of 3.85 g of CaCl 4 solution and 19 1 3.67 η Mg (KOo) ₂ solution and 25 1 of water for 3 h at 348 K stirred »Then it was filtered off and washed and dried at 385 K overnight»

The CaMg Y zeolite powder thus prepared was ground and treated with platinum tetrammine chloride solution until the product contained 0.75 mass% Pt.

After admixing finely ground aluminum oxide powder in an amount of 30% by mass (based on the residue on ignition at 1070 K) to 70 mass- $ 6 of the platinum-containing CaMg Y zeolite, this mass was reduced to cylindrical pills of 5 mm diameter and 5 mm on a hydraulic press Height deformed · The moldings had a high mechanical strength and a bulk density of 880 g / l (Catalyst 1) »

Example 2

From a commercially available Na ~ Y zeolite having a SiO.sub.p / AlpOo molar ratio of 4.9, 87 % of the sodium chloride ions were replaced by rare earth cations by repeated exchange with 0.3M didymnitrate solution at 363 K and intermediate filtration and washing. · After the last ion exchange filtered * washed and dried at 385 K * 4 kg of this SS-Y zeolite powder (based on the ignition residue at Ϊ070 K) were mixed with 2.5 kg of a natural, kaolinithaltigen clay (based on the ignition residue at 1070 K), 3 1 of an alkali-free 25% Kiesekols and 3 1 of a 6% aqueous

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Äthylzelluloselösimg kneaded in a kneader and extruded into hollow strands with 5 mm outer diameter and 1.5 mm inner diameter. The hollow strands were dried after drying by standing in air in a dried air stream with 4 K / min · heated to 723 K, 2 h at 723 K in the air stream, cooled to 423 K, hurried with dry nitrogen, in the dried hydrogen stream with 6 K. / Min, heated to 723 K and cooled again · 0.6 mass of platinum was applied to the thus treated hollow strands by ion-exchange impregnation and then dried at 385 K. The moldings had a bursting pressure of 15.5 Kp / molding, an edge strength of 5.1 kp / molding and a bulk density of 365 g / l (catalyst) »

Example 3

By means of ammonia water (25% by mass of NH 3), alumina hydrogel was prepared from a nitrated aluminum nitrate solution (100 g of Al ₂ O 3/1 and 25 g of HNO 3/1) at pH 8.0 and a pH temperature of 330 K precipitated · After filtering and washing a filter cake with 21.8 Mas se-JS ^a was - ^ 2 ^ 3 ^ΘΓ ^ ⁸ ^ "* th" 20 kg of the filter cake were placed in a mixer by addition of 340 ml of nitric acid ( 50%) at room temperature in a Aluminiumoxidhydrosol I transferred ·

The hydrosol I was heated for 4 h at 370 K in an autoclave with stirring and thus transferred to the hydrosol II "5 kg of the hydrosol II were 9.1 kg (based on the ignition residue at 1070 K) of the described in B _e play 1 , platinum-free CfiMg Y zeolite powder intensively mixed in a kneading machine, the mixture gelled with 375 ml of ammonia water and extruded through an extrusion machine to 3 mm extrusions · The moldings were dried at 380 K and annealed at 800 K. «» The moldings had a bursting pressure of 21 kp / molding and an edge strength of 7.2 kp / molding and a bulk density of 560 g / l »

The whole-stranded formates were impregnated with an aqueous solution of platinum-tetrammine chloride to give a supernatant

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a platinum content of 0.6% by mass is applied (Catalyst 3) »

Example 4

From a nitric acid solution of aluminum nitrate (100 g of Al 2 O 3 / l and 25 g of HNO 3/1) an alumina hydrogel was precipitated by means of ammonia water (25% by mass) at a pH of 8.8 and 343 K under a water feed. After filtration and washing, a filter cake containing 23.5% by weight of aluminum oxide was obtained. The filter cake was converted into a hydrogenated oil I in a mixing vessel by reaction with 50% strength HIOl in an amount of 18.5 ml / kg of filter cake at room temperature. .

DqS hydrosol I was in a stirred autoclave for 5 h at "375 K be and thereby converted into the hydrosol II,

6 kg of the hydrosol II were mixed with 3.35 kg (based on the ignition residue at 1075 K) of the prepared according to Example 1 platinum-free CaMg Y zeolite in powder form with the addition of 1850 ml V / asser until the viscosity reached 0.07 cP »This mixture was coagulated by dripping in ammonia water ,, The dripping balls obtained after drying have a very smooth surface, high mechanical strength and a bulk density of 450 g / 1 * The dripping balls were by impregnation with an aqueous solution of platinum tetrammine chloride after a conventional Method applied a Pt content of 0.6% by mass (Catalyst 4) «

Example 5

5.2 kg of a commercially available Na Y zeolite with a SiO ₂ /

was 4.9 with 9 1 3.7 η CaCl ₂ -Lo

Solution, 6 1 3.6 η Mg (NOo) ₂ solution and 10 1 of water for 7 h at ^ 63 K stirred * Then it was filtered and washed and the powder dried at 385 K * 3.35 kg (based on the Glue residue at 1070 K) of the ground CaMg Y zeolite thus prepared were mixed with 6 kg of the

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Hydrosols II, which was prepared in the manner indicated in Example 4, mixed with the addition of 1800 ml of water until the viscosity reached 0.08 cP · This mixture was coagulated by grafting into ammonia water. The dripping balls obtained had a smooth surface and a high mechanical strength after drying. The dripping balls were calcined at 750 K for 6 hours.

4 kg of the calcined dripping balls were treated with 5 l of a solution which was 27% Mg (NO 0) ₉ ¹ cL of Ca (JTO-J) ₉ for 6 h at 350 K. After washing and drying, a Pt content νοηΟ, β mass% was applied by ion-exchanging impregnation with platinum tetrammine chloride solution. The catalyst 5 thus produced had a bulk density of 435 g / l.

Of the examples, only the methods of Examples 3, 4 and 5 correspond to the method of the invention. Comparative catalytic measurements were carried out with all five prepared Y zeolite catalysts under conditions which were very close to the technical ones. The test duration was 300 hours in each case. It was a technical raw material, a light benzene fraction with a boiling range of 303 to 363 K and the composition (in mass%):

: 11,8: 11,4

UC ₅ ': 19.0

iso-C ₆ : 22.2

nc ₆ : 17,9

other KW: 17.7

ROZ '^ (without Pb): 65,0

The isomerization of this fraction was carried out with TOOO ml of catalyst at 25 at .; 2.0 v / vh and a gas-product ratio of 1000 Nl / 1 · The following table contains the results achieved:

Table: Catalytic properties of the catalysts prepared according to Examples 1 to 5 in the isomerization of a technical grade benzine fraction

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catalyst

Reaction temperature ROZ _ß Liquid > K (without Pb) prey mass%

2 3 4 5

618 71.5 96.5 598 72.5 97.0 588 73.5 98.1 583 74.0 98.6 578 74.0 98.5

The results summarized in the table show that the catalysts 3, 4 and 5 prepared by the process according to the invention are not only suitable for industrial use because of their good mechanical properties but that Y zeolite catalysts having significantly better catalytic properties are produced by the production process according to the invention The process according to the invention makes it possible to fully bring out the good catalytic properties of a Y zeolite catalyst mass (cf. Catalyst 1 with Catalysts 3 and 4). The advantage of the process according to the invention is expressed both in the lower reaction temperature A further advantage is that better catalytic results are achieved than with conventionally prepared catalysts, although less catalyst mass in the reactor (lower bulk density of the catalysts produced according to the invention) was incorporated.

Claims (11)

1 * Process for the preparation of alumina-containing Y zeolite catalysts for the isomerization of low-boiling η paraffins of different porosity by coagulation of alumina hydrosol and ion-exchanged Y zeolite-containing mixtures, characterized in that the peptization of the alumina hydrogel is carried out in two stages, wherein, in the first stage, a predominantly boehmite-containing hydrogel is converted with an acid / hydrogel acid / hydrogel acid molar ratio from 0.05 to 0.20 at room temperature into a hydrosol I low dispersity and viscosity, and in the second stage hydrosol I through Heating to temperatures of 323 to 423 K in a hydrosol II and heated until the desired degree of dispersity is reached, the hydrosol II optionally in combination with other components with the addition of finely ground ion-exchanged Y-zeolite under reaction with a coagulant forming molds which are thermally post-treated in known W _e ise and further processed · 2 Method according to item 1, characterized in that oxide hydroxide precipitated or precipitated with aluminum trihydroxide as wet filter cake is preferably used as almnium oxide hydrogel, above a pH of 7.5. Process according to item 1, characterized in that oxide hydroxide precipitated or precipitated by precipitation, preferably above pH 7.5, or its mixtures with aluminum trihydroxide in dried, finely ground form is used as the peptisable oxide hydroxide gel. 4 * Process according to point 1 to 3 »gekennaeichnet characterized in that the water content of the hydrosol I formed in the first stage is set in the limits of 6Ö to 90 % · -11 ο 1 ζ ^ A 5 "Process according to items 1 to 4, characterized in that nitric acid / hydrogen halides and carboxylic acids are used as acids forming basic salts.« 6 * Process according to item 1 to 5, characterized in that the heating of the hydrosol I ± n second stage takes place at temperatures of 323 to 423 K for 0.1 to 24 h * 7 · Method according to items 1 to 6, characterized in that the concentration of the substance to be formed reaches. Hydrosols and their combinations with other components is 150 to 400 g / l · 8 »Process according to items 1 to 7, characterized in that the hydrosol II hydrosol I and / or AluminUm hydrogel and / or alumina and ion-exchanged Y-zeolite in amounts of 1 to 80 % mixed /» Process according to items 1 to 7, characterized in that finely-milled ion-exchanged Y zeolite is added to the hydrosol II in an amount of from 1 to 80 %, based on the weight of the calcined product. Soldering according to item 1, 8 and 9, characterized in that the ion exchange of Y ~ zeolite one or more stages with or without intermediate heat treatment with solutions or melt of salts with ammonium ions and /. or with divalent and trivalent cations «, - ¹⁰ - 2 15 5 4 8 Claim for invention 11 »process according to item 1 to 10, characterized in that the shaped bodies are thermally treated, optionally subjected to one or more further ion exchange processes and with platinum and / or palladium in the form of their Arnmirskomplexe in an amount of 0.1 to 1.0 mass - % of the precious metal to be impregnated «