DE102004040522A1 - Acidic tungsten-containing catalyst - Google Patents

Abstract

The invention relates to a process for preparing a preferably shaped catalyst, comprising (a) intensive mixing or kneading at least one zirconium oxide and / or hydroxide component, at least one aluminum oxide and / or hydroxide component and a tungsten-containing component; (b) shaping the mixture; (c) Calcination at temperatures above 700 ° C., in particular above 800 ° C. A catalyst obtainable by this process and its use, in particular for the isomerization of hydrocarbons, are also described.

Description

The Invention relates to a process for the preparation of a catalyst, in particular for the heterogeneous catalysis of acid-catalyzed reactions, one obtainable by this method, preferably shaped catalyst and its use.

in the The prior art is a series of acidic oxide Zr and / or W catalysts known. Many of these catalysts are used for isomerization of paraffins, in particular light paraffins, according to conventional Refinery processes used.

For example, WO 95/03121 relates to a modified oxidic catalyst which is used in particular for the isomerization of C ₄ to C ₈ paraffins.

The zirconium oxide / tungsten oxide catalysts described there, for example, are pulverulent, impregnated catalysts. In later pamphlets, like the US 5,510,309 or 5,719,079, corresponding coprecipitated catalysts are preferred because of the higher activity.

It However, there is a permanent one Need for acidic tungsten-containing catalysts that a high selectivity and a high activity have good service life, and corresponding methods for Preparation of such catalysts.

These The object is achieved by the method according to claim 1.

So was surprising found that by intensive mixing or kneading a Zirconium oxide and / or hydroxide component, an alumina and / or Hydroxide component and a tungsten-containing component and then common Forming and calcining the mixture is particularly active and selective Catalysts can be generated which enable high product sales.

It was further found to be doing the common calcination the above components is of crucial importance. So shows a catalyst in which the alumina and / or hydroxide component only after the calcination of the catalyst in conventional As a binder is added, no or a lower activity.

Furthermore, it has been found that when using a fresh co-precipitated W-oxide / Zr oxide component, which according to the US 5,510,309 or 5,719,079 a W-oxide-impregnated Zr oxide is preferred due to the higher activity, the addition of an aluminum oxide or hydroxide component has a strong nega tive influence and leads to a nearly inactive catalyst.

Consequently was surprising found that the Al component on Zr oxide / W oxide, in particular in terms of the activity and selectivity of the catalyst in the isomerization of hydrocarbons has an unexpectedly strong influence, depending on from the time of addition of the Al component. Even the ratio of activities when using a co-precipitated W oxide / Zr oxide component compared to a catalyst, the made of isolated W and Zr components, turns in the presence of the Al component, so that by adding the Al component to the isolated W and Zr components the re activity and selectivity best catalyst is obtained.

These Results suggest that the effect of the Al component over the conventional Binder effect goes out in the formation of the catalyst and the active centers of Zr oxide / W oxide are positively influenced.

When Zr-containing component may in particular zirconium oxide or zirconium hydroxide or their mixture can be used. In particular, as an Al component Alumina, aluminum hydroxide or a mixture thereof are used.

The tungsten-containing components which can be used in the context of the present invention are familiar to the person skilled in the art and, in particular, include, but are not limited to, tungstate salts. Especially beneficial results are achieved with the use of metatungstate as the tungsten-containing component.

The Forming the mixture of the zirconium oxide and / or hydroxide component, the alumina and / or hydroxide component as well as the tungsten-containing component preferably under conventional Extrusion of the mixture, with the preferred size and shape of the extrudate freely selected can be.

It However, other, known to those skilled devices for molding of the above mixture in the context of the present invention conceivable.

The according to step b) molded mixtures obtained from claim 1 are at relatively high Temperatures above about 700 ° C, especially about about 800 ° C, calcined. usual Calcination times range between about 1 and about 5 hours. It goes without saying an interaction between the calcination temperature and the calcination time such that at higher Calcining temperatures a shorter one Calcining time may be sufficient, and vice versa.

It was found to be relatively high Calcining over about 700 °, especially about about 800 to about 890 ° C, preferably up to about 850 ° C, give particularly advantageous catalysts.

To a particularly preferred embodiment of the present invention the catalyst further comprises a hydrogenation / dehydrogenation component. These is preferably in an amount between about 0.001% by weight to about 5% by weight, based on the total weight of the (finished) catalyst, available.

To An advantageous embodiment according to the invention comprises the hydrogenation / dehydrogenation component a metal component from Groups VIII, IX and X of the Periodic Table. Particularly preferred are noble metals such as platinum and palladium.

To a further embodiment of the invention however, the hydrogenation / dehydrogenation component may still be a non-noble metal in the form of at least one oxide, hydroxide or metal at least of an item selected from the group of Group VIII, VIa, Vb and VIIb metals.

Preferably the hydrogenation / dehydrogenation component is supported on the Zr, Al and W component applied. According to a particularly preferred embodiment is doing the above carrier with a salt of the hydrogenation / dehydrogenation component after calcination impregnated.

As mentioned above, are characterized by the catalysts obtained by the process according to the invention by a considerably higher Sales compared to traditional Process produced catalysts of the same selectivity in the Isomerization of Kuhlenwasserstoffen.

One Another aspect of the present invention therefore relates to a Catalyst, in particular a shaped catalyst according to obtainable by the above method is.

Of the catalyst according to the invention can generally be used for the heterogeneous catalysis of acid-catalyzed reactions be used.

A particularly preferred embodiment relates to the use of the catalyst for the conversion, in particular for the isomerization, alkylation or hydrocracking of hydrocarbons. Hydrocracking is preferably carried out under mild conditions, in particular with Fischer-Tropsch Wax. What is to be understood by Fischer-Tropsch Wax and mild hydrocracking is familiar to the person skilled in the art and therefore need not be explained in more detail here. Briefly, Fischer-Tropsch Wax are waxy paraffin products of the Fischer-Tropsch synthesis. As a non-limiting example of typical mild hydrocracking conditions, the following may be mentioned: pressure = 50-80 bar; Temperature = 370/430 ° C (SOR / EOR); LHSV = 0.5 - 1.0 h-1; H ₂ / Oil Ratio = 500 - 1000 Nm ³ / m ³ ; Severity = 30/20 (SOR / EOR).

A particularly preferred use relates to the isomerization of C ₄ to C ₁₀ hydrocarbons, in particular the C ₇ / C ₈ isomerization of hydrocarbons.

In the isomerization of hydrocarbons, it has been found that those catalysts of the invention having a BET surface area of not more than about 150 m ² / g are preferred. The BET surface area of the catalysts was determined according to DIN 66131.

The Invention will now be described with reference to the following non-limiting Examples explained.

Example 1 (comparison): (WO ₃ / ZrO ₂ )

1000 g of zirconium hydroxide (MEL XZO632 / 03) are mixed in a kneader (Werner & Pfleiderer, Z-kneader) with a solution of 300 g of ammonium metatungstate ((NH ₄ ) ₆ H ₂ W ₁₂ O ₄₀ ) in 200 ml of water and stirred for 10 min kneaded. Then, to the mixture are successively added with kneading 50 g of Methocel (cellulose ether DOW), 70 g of steatite oil and 180 g of deionized water. The resulting mixture is blown with cold air for 45 minutes until the mass reaches a consistency so that it can be extruded.

The obtained mixture is extruded (extruder from Fuji Paudal Co. Ltd .; Model: EXKFS-1, speed setting 0.4). The diameter the extrusion is 1.6 mm.

The extrusions are dried for 15 h at 40 ° C in a drying oven and then calcined with the following temperature program:
Heating from RT to 800 ° C with a heating rate of 150 ° C / h. Keep at 800 ° C for 3 h, cool from 800 ° C to RT at a rate of 150 ° C / h

The thus obtained product is called catalyst 1.

The Extrusions can optional with a solution of hexachloroplatinic acid soaked in water in the way be that a Pt content achieved on the finished calcined catalyst of 0.5 wt .-% becomes.

The extrusions are then dried for a further 15 hours at 40 ° C. in a drying oven and then calcined with the following temperature program:
Heating from RT to 550 ° C at a heating rate of 200 ° C / h Keep 550 ° C for 3 h Cool from 550 ° C to RT at a rate of 200 ° C / h.

The the product thus obtained is designated as catalyst 1 / Pt.

Example 2: (WO ₃ / ZrO ₂ / Al ₂ O ₃ )

500 g of zirconium hydroxide (MEL XZO632 / 03) are mixed in a kneader (Werner & Pfleiderer, Z-kneader) with a solution of 150 g of ammonium metatungstate ((NH ₄ ) ₆ H ₂ W ₁₂ O ₄₀ ) in 100 ml of water and stirred for 10 min kneaded. Then, to the mixture, 500 g of Pural SCF 55 (Al binder of Condea), 30 g of steatite oil and 400 g of VE water are successively added with kneading. The resulting mixture is blown with cold air for 45 minutes until the mass reaches a consistency so that it can be extruded.

The obtained mixture is extruded (extruder from Fuji Paudal Co. Ltd .; Model: EXKFS-1, speed setting 0.4). The diameter the extrusion is 1.6 mm.

The extrusions are dried for 15 h at 40 ° C in a drying oven and then calcined with the following temperature program:
Heating from RT to 800 ° C at a heating rate of 150 ° C / h. Holding at 800 ° C for 3 h. Cooling from 800 ° C to RT at a rate of 150 ° C / h.

The thus obtained product is referred to as catalyst 2.

The Extrusions can optional with a solution of hexachloroplatinic acid soaked in water in the way be that a Pt content achieved on the finished calcined catalyst of 0.5 wt .-% becomes.

The extrusions are then dried for a further 15 hours at 40 ° C. in a drying oven and then calcined with the following temperature program:
Heating from RT to 550 ° C at a heating rate of 200 ° C / h Keep 550 ° C for 3 h Cool from 550 ° C to RT at a rate of 200 ° C / h.

The the product thus obtained is designated as catalyst 2 / Pt.

Example 3 (comparison): (½WO ₃ / ZrO ₂ )

1000 g of zirconium hydroxide (MEL XZO632 / 03) are mixed in a kneader (Werner & Pfleiderer, Z-kneader) with a solution of 150 g of ammonium metatungstate ((NH ₄ ) ₆ H ₂ W ₁₂ O ₄₀ ) in 100 ml of water and stirred for 10 min kneaded. Then, to the mixture are successively added with kneading 50 g of Methocel (cellulose ether DOW), 70 g of steatite oil and 160 g of deionized water. The resulting mixture is blown with cold air for 45 minutes until the mass reaches a consistency so that it can be extruded.

The obtained mixture is extruded (extruder from Fuji Paudal Co. Ltd .; Model: EXKFS-1, speed setting 0.4). The diameter the extrusion is 1.6 mm.

The extrusions are dried for 15 h at 40 ° C in a drying oven and then calcined with the following temperature program:
Heating from RT to 800 ° C at a heating rate of 150 ° C / h. Holding at 800 ° C for 3 h. Cooling from 800 ° C to RT at a rate of 150 ° C / h.

The the product thus obtained is referred to as Catalyst 3.

The Extrusions can optional with a solution of hexachloroplatinic acid soaked in water in the way be that a Pt content achieved on the finished calcined catalyst of 0.5 wt .-% becomes.

The extrusions are then dried for a further 15 hours at 40 ° C. in a drying oven and then calcined with the following temperature program:
Heating from RT to 550 ° C at a heating rate of 200 ° C / h Keep 550 ° C for 3 h Cool from 550 ° C to RT at a rate of 200 ° C / h.

The the product thus obtained is referred to as catalyst 3 / Pt.

Example 4 (comparative): (coprecipitated WO ₃ / ZrO ₂ + Al binder)

1000 g of fresh coprecipitated WO ₃ / ZrO ₂ are prepared analogously to US Pat. No. 5,510,309 Example 2 and, after being filtered off, still wet after being filtered off into a kneader (Werner & Pfleiderer, Z-kneader). For this purpose, 500 g of Pural SCF 55 (Al binder from Condea), 30 g of steatite oil and 100 g of demineralized water are added in succession with kneading and kneaded for 10 minutes. The resulting mixture is blown with cold air for 45 minutes until the mass reaches a consistency to appear extrudable.

The obtained mixture is extruded (extruder from Fuji Paudal Co. Ltd .; Model: EXKFS-1, speed setting 0.4). The diameter the extrusion is 1.6 mm.

The extrusions are dried for 15 h at 40 ° C in a drying oven and then calcined with the following temperature program:
Heating from RT to 800 ° C at a heating rate of 150 ° C / h. Holding at 800 ° C for 3 h. Cooling from 800 ° C to RT at a rate of 150 ° C / h.

The thus obtained product is referred to as Catalyst 4.

The Extrusions can optional with a solution of hexachloroplatinic acid soaked in water in the way be that a Pt content achieved on the finished calcined catalyst of 0.5 wt .-% becomes.

The extrusions are then dried for a further 15 hours at 40 ° C. in a drying oven and then calcined with the following temperature program:
Heating from RT to 550 ° C at a heating rate of 200 ° C / h Keep 550 ° C for 3 h Cool from 550 ° C to RT at a rate of 200 ° C / h.

The the product thus obtained is designated as catalyst 4 / Pt.

Example 5: C5 isomerization

The prepared catalysts are in the isomerization of n-pentane tested to iso-pentane. As a result, lighter by-products are formed Alkanes that are not wanted are.

• – 8 mm Reaktor
• – 2 g Katalysator (0,5 – 1mm Siebfraktion)
• – 20,71 Nml/min Wasserstoff
• – 0,107 Nml/min n-Pentan
• – 20 barg
• – Reaktortemperatur 200°C
• – H₂ : HC = 1 : 1 mol : mol
• – LHSV = 2 1/h

The test is carried out in a microreactor under the following experimental conditions:

• - 8 mm reactor
• 2 g of catalyst (0.5-1 mm sieve fraction)
• - 20.71 Nml / min of hydrogen
• - 0.107 Nml / min of n-pentane
• - 20 barg
• - Reactor temperature 200 ° C
• H ₂ : HC = 1: 1 mol: mol
• - LHSV = 2 1 / h

The Analysis takes place by means of an online GC, in which every 15 min Measuring point is detected.

test results

• %Sales

  = 100% by weight n-pentane

  %Selectivity

  = Wt% iso-pentane / (100% by weight) n-pentane) * 100%

Test results C ₅ isomerization at 230 ° C:

catalyst 2 is significantly more active than the catalysts without binder.

Example 6: C ₇ isomerization

The prepared catalysts are in the isomerization of n-heptane tested to iso-heptane. execution and evaluation are carried out analogously to Application Example 1, except that Here 0.107 ml / min of n-heptane are added as feed.

Test results C ₇ isomerization:

catalyst 2 is significantly more active than the catalysts without binder or the Catalyst with the co-precipitated W oxide / Zr-oxide. Therefore, it can be driven at the same conversion at a lower temperature be, resulting in a much higher selectivity results.

Example 7: C ₈ isomerization

catalyst 2 was added tested in the isomerization of n-octane to iso-octane. Implementation and Evaluation is carried out analogously to Application Example 1, except that here 0.107 ml / min of n-octane are added as a feed.

Test results C ₈ isomerization:

It can be seen from the above test results that the catalyst prepared according to the invention also showed very good results in C ₈ isomerization.

Claims (14)

Process for the preparation of a shaped catalyst, comprising the following steps: a) intensive mixing or kneading at least one zirconium oxide and / or hydroxide component, at least one alumina and / or hydroxide component as well a tungsten-containing component; b) shaping the mixture; c) Calcination at temperatures above 700 ° C, especially over 800 ° C. Method according to claim 1, characterized in that that the tungsten-containing component is a tungstate, especially a metatungstate. Method according to claim 1, characterized in that that in step b) of claim 1 is extruded. Method according to one of the preceding claims, characterized characterized in that the catalyst is a hydrogenation / dehydrogenation component is added. Method according to one of the preceding claims, characterized characterized in that the hydrogenation / dehydrogenation component with 0.001 to 5 wt .-%, based on the total weight of the catalyst, is present. Method according to one of the preceding claims, characterized in that the hydrogenation / dehydrogenation component is a metal component from Groups VIII, IX or X of the Periodic Table or a mixture from such metal components. Method according to one of the preceding claims, characterized in that the hydrogenation / dehydrogenation component continues at least one non-noble metal in the form of at least one oxide, Hydroxide or metal of at least one element selected from the group of metals of Group VIII, IVa, Vb and VIIb contains. Method according to one of the preceding claims, characterized characterized in that the hydrogenation / dehydrogenation component of the zirconium, tungsten and aluminum-containing carrier is worn. Catalyst, available according to a method according to the claims 1 to B. Catalyst according to claim 9, characterized in that it has a BET surface area of not more than 150 m ² / g and / or is formed. Use of a catalyst according to claim 9 or 10 or one according to a method according to one of claims 1 to 8 prepared catalyst for catalysis of acid-catalyzed reactions. Use according to claim 11 for isomerization, Alkylation or hydrocracking of hydrocarbons. Use according to claim 11 or 12 for the isomerization of C ₄ to C ₁₀ hydrocarbons, in particular for the C ₇ / C ₈ isomerization of hydrocarbons. Use according to claim 11 or 12 for mild hydrocracking of hydrocarbons, in particular Fischer Tropsch wax.