DE2012939A1 - Steam reforming catalysts - Google Patents

Description

Patent application for

THE GAS COUNCIL, 59 Bryanston ütreet, Marble Arch, London, W.1

(Great Britain)

concerning
Catalysts for Y / ater vapor reforming

The invention relates to catalysts for steam reforming, i.e. catalysts used for reforming hydrocarbons can be used with water vapor.

The invention relates on the one hand to a catalyst for the reforming of hydrocarbons with water vapor, which contains a catalyst support on which Nicke'loxyd and / or nickel, together with one or more oxides of uranium, is deposited, the weight ratio between uranium and nickel on the catalyst supports 0.62: 1 amounts to 0,74s1 and the total weight of nickel and uranium on the catalyst support (if the nickel in the oxidised state, ie as NiO, is present) does not make up more than 20 ^o / o by weight of the catalyst. The weights of the nickel and uranium indicated above relate to the weights of the metals which are present both in elementary form and as compounds. .

(Calculated as metals) The total weight of nickel and uranium usually does not less than 2 wt _o - $ of the catalyst. When reforming methane, the proportion is

009841/1011

BATH

of these two metals preferably 5 to 10> 6, for example 7 yu. In the case of higher hydrocarbons, for example naphtha, the proportion of these two metals is preferably $ 10 to $ 20, preferably $ 15 to $ 20, for example 18 %. If the ratio between uranium and nickel is between 0.63 and 0.64s1, the catalyst contains about 7 $ uranium in the form of an oxide (e.g. UO ₃ , U ₃ O ₃ or U ₄ O ₉ ) and about 11 ° nickel in the form of nickel oxide.

The carrier on the surface of which the active ingredients are formed is preferably Λ-alumina. But Ss can also other carriers are used, for example 5-alumina, molecular sieves, Zirconium silicates, silicon carbide, silicic acid and natural clays and aluminosilicates.

The term "catalyst" as used in the description refers either to the catalyst in its active form or to a catalyst in an easily activated form, the activation often taking place under the conditions of the reaction to be catalyzed. In the present case, nickel oxide is not an active catalytic component. However, if it is reduced to nickel, in which case the reduction can take place under the conditions of the steam reforming reaction, the catalyst becomes abnormal . The term "thermally decomposable compounds ¹¹ " used in the description should not include any residues or groups which could poison the catalyst, e.g. sulfides, halide or arsenic compounds,

3s it may be desirable that the catalyst also has a barium cora ^ - contains one or more compounds, such as barium oxide, barium hydroxide, barium carbonate, barium uranate and compounds, which decompose into the specified compounds when heated. The barium component is expedient Impregnation of the catalyst carrier with barium hydroxide or a compound which, when heated, turns into barium oxide, barium hydroxide, Barium carbonafc or barium uranium decomposed, built-in.

009841/18 11 bad original

A preferred catalyst according to the invention can also be prepared by having a catalyst support that Barium oxide in an amount of not more than 20 wt .- $, based on the catalyst, is prepared by barium oxide or a compound which decomposes to barium oxide on heating with the other component or components of the catalyst support or with a compound or with compounds; which when heated to this component or components decompose, mixed, whereupon the mixture thus formed is optionally caloinated and then the nickel and Uranium components of the catalyst on the surface of the catalyst support brings up. I.

The catalyst appropriately contains a small amount of potassium oxide, preferably no more than 2% by weight potassium. The amount of "available" potassium is preferably 0.6 to 1.2 #, e.g. 0, ö > "ί, although the catalyst also works with potassium concentrations of 0.2 up to 0.3% by weight? » is effective. Under the term "available potassium" one understands the potassium present in the catalyst, which cannot be extracted by water or hydrofluoric acid, but that can be extracted by hydrochloric acid. Instead of the potassium oxide / an equivalent amount of lithium oxide can be used. is If there is a 3arium component in the catalyst, only a small amount (e.g. 0.5 ";«) of lithium or potassium oxide needs to be added to the j Catalyst to be incorporated, 'and these compounds can before, simultaneously with or after the addition of the nickel and uranium components can be added, cjo can be an oälz, e.g. a nitrate of lithium or, preferably of potassium, can be used to impregnate the catalyst or the catalyst support.

If the catalyst support is RT-alumina, it may be preferable be that the carrier does not contain more than 0.07% by weight of sodium, calculated as sodium oxide, based on the weight of the carrier, contains. When such a carrier is used, it is also desirable that sulfur be added in amounts less than 50 p.p.m. and • Silicon, calculated as al3 SiOo, in amounts of less than 0.14 wt.; Fe is available.

00 9-841 / 1811 _b ad

If the carrier contains barium, the alkali metal compound, based on the alkali metal equivalent, is preferably present in amounts of not more than 0.15 to 3 %, preferably not more than about 0.2%.

The to apply the active components of the catalyst on The methods used for the catalyst surface are those customary in the manufacture of catalysts. In this regard, will to British Patent 1,039,206 and Belgian Patent 699 949 pointed out, in which processes for the production of catalysts with similar components as the catalyst ^ sators according to the invention are described; in particular are there the following general processes for the preparation of catalysts are described:

1. The catalyst can be prepared by impregnating a carrier with an aqueous solution of nickel and uranium salts, optionally together with a potassium or lithium salt, whereby the salts can be converted into the oxides of the corresponding metals by heating (e.g. titrates). Each impregnated carrier can then be heated to produce a catalyst according to the invention. Soaking can be done in one otufe or with just one metal at a time.

2. The catalyst can be produced by a process

in which the Iraqi with a uranium salt from an aqueous Ιοί
solution is soaked and dried, whereupon the impregnated carrier is placed in an ammonia solution to convert the uranium salt into ammonium diuranate, whereupon the diuranate is thermally decomposed to uranium oxide.

If necessary or desired, a binder can be incorporated into the catalyst.

(Jute catalysts can be obtained using a salt of a carboxylic acid, preferably the acetate of nickel and / or the.

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201293S

Uranium, which is located on the carrier surface, is subjected to a controlled decomposition at a temperature of not more than 65O ⁰ O. This mode of operation is described in Belgian patent 700,310. However, the method described in Belgian patent specification 700'311 can also be used. In the latter process, after its formation, the catalyst is subjected to a reduction and then to an oxidation in the presence of reducing or oxidizing gases, for example hydrogen and air, with smaller crystallites being obtained.

If a barium component is present in the catalyst, it can the catalyst can be prepared by a number of general procedures. .

In one method, the barium component of the catalyst is added to the support prior to the formation of the nickel and uranium components or their precursors on the support surface. The carrier can be mixed with an aqueous solution of a barium compound, e.g. a carboxylic acid salt, such as. Barium acetate, or preferably soaked in barium hydroxide. When heated to about 30O ⁰ O, the hydroxide is at least partially decomposed to the oxide. Is the acetate used is obtained by heating to a temperature of about 55O ⁰ O essentially barium carbonates

As soon as the barium compound has been incorporated into the carrier by this process, the carrier can be impregnated with nickel and uranium compounds, for example with nickel and uranium nitrate, which can then be decomposed to the metal oxides. If nitrates are used, the decomposition can be achieved by heating the catalyst. tors to about 65O ⁰ O «

According to a second method, the catalyst support becomes simultaneous soaked with the salts, e.g. with the acetates of Nikkeis, Uranium and barium, which exist in an aqueous solution lying »The oxides of nickel and uranium can be formed by heating the impregnated catalyst; will

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acetate is used, temperatures of about 500 to 610 C.

According to a third method, the carrier is first placed in a solution the nickel and uranium compounds, e.g. nickel and uranium nitrate, which are then decomposed to form the metal »· To form oxides, a barium compound is used on this impregnated carrier applied in solution, for example a carboxylic acid balz, such as barium acetate or preferably barium hydroxide, The barium compound can then be partially decomposed to the oxide by heating the support.

According to a fourth process, the catalyst is produced by that, in a suspension, a thermally decomposable gas of barium, e.g. the hydroxide or a carboxylic acid salt, like the acetate of barium, together with the other components of the carrier in powder form, e.g. powdered aluminum oxide, is mixed. The calcination is preferably carried out at a relatively high temperature, so that a thorough Decomposition is guaranteed. In cases where barium hydroxide is used as a precursor for the uarium oxide, the calcining temperature is preferably above 1500 ° G, a.B. at about 1650 G. If barium acetate is used, the calcination temperature is preferably about 1500 G.

In any case, the parts of the components are on the carrier determined by the concentration of the soaking solution and the duration of the soaking.

The invention also relates to a process for reforming methane and higher hydrocarbons, in particular naphtha, in the presence of water vapor, usually in the vapor phase. The temperature at which the process is carried out is preferably about 650 to 75O ⁰ G. The catalyst preferably has the form of Hung, spheres or hollow cylinders.

The invention is illustrated by the following examples of catalysts

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and explained for the procedure.

example 1

Barium hydroxide and powdered clay are mixed with one another in a suspension, shaped and calcined ^{at a temperature of 165O 0 O.}

The resulting! Carrier is then impregnated with a solution of nickel and uranium nitrate and subsequently heated to ⁰ G GOO, g wherein a catalyst is obtained containing 1.0 wt .-? * Contains barium oxide *. .

Bite game 2

Example 1 is repeated with the difference that potassium nitrate is added to the suspension, 0.2 $ potassium equivalents being present as potassium oxide in the carrier.

Example 3

Example 1 is repeated with the difference that barium acetate is used instead of barium hydroxide. The Galcinierung A is carried out at a! Temperature of 15:00 ^0C.

Example 4

Example 3 is repeated except that the suspension is added potassium nitrate, where 0 * 2 $ potassium equivalents i "carrier vorliege".

: -'- ■:. ■ -; ■: ';,': ' Appendix 5 ''". - -

Shaped corundum supports are immersed in a bath containing an aqueous solution of Kicjcei and TJra nitrate. The impregnating carrier is at 65O ⁰ G, calcined. around the metal nitrates

^ BADORlGiNM,

to convert into the corresponding oxides and then impregnated with an aqueous barium hydroxide solution. After calcining at 300 G ⁰ is obtained a catalyst which 10.8 wt .- ^ nickel, 6.7 wt .- $ uranium and 0.8 wt. $ Contains barium oxide.

Example 6

The catalyst prepared according to Example 5 is poured into a reaction tube. At 420 ^° C., water vapor is in a narrow range of about 82 kg / dtd. (180 Toyota.) And naphtha in an amount of about 18 liters / otd. (4 gall./hd.) Into the reactor. The starting temperature is 76O ⁰ C.

The system was in operation for 1700 hours. After that the throughput was the reactant gradually increased to about 73 liters / hour. (16.5 gall./otd.) Flash distillate flow (primary flash distillate) and about 196 kg / otd. (433 lbs./hd.) Water vapor elevated. The pressure in the reactor was about 30. $ at (448p.s.i.).

The gas formed had the following composition:

Hydrogen $ 62>

! dethane $ 13.83>

CO $ 9.76>

CO ₂ '16.67 #

C ₂ H ₆ ■ '0.0059 $>

C ₂ H ₄ 0.002 #

C ₃ H ₃ 0.002 $>

The liaphtha used had a final boiling point of 123? C.

3EI steam reforming reactions, the catalysts according to the invention particularly advantageous kel-uranium catalysts over other Nik, .da a substantially lower carbon

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BATH ORIGINAL

- 9 -. ■■■■,

Deposition occurs as shown in the accompanying drawing is. The drawing shows that the stability of catalysts with a uranium / nickel ratio of 0.62-0.74i1 of the catalyst versus carbon deposition on the guns' The latter parameter is given in the curve as the reciprocal time it takes for a A pressure differential of about 100 p.s.i, g.) Is required is. If the proportion of the active metals is not more than 20 wt .- ^ of the catalyst, the Eafcalysator has one stronger structure, and its manufacture is more economical.

A modified embodiment of the invention relates to a | Catalyst for reforming hydrocarbons; the catalyst contains

1. Nickel and / or nickel oxide and / or a compound that decomposes when heated in the specified substances;

2. A uranium oxide and / or a compound that changes when heated decomposed into uranium oxide; -

3. Barium oxide, barium hydroxide, barium carbonate, barium uranate and / or a compound which, when heated, becomes part of the decomposed compounds mentioned; and

4. a catalyst support, the barium component being incorporated into the catalyst in that the support with barium hydroxide or a barium compound which, when heated, turns into barium oxide, barium hydroxide, barium carbonate | nat or barium uranium is decomposed, impregnated.

-Patent claims- 009841/1811

BATH ORIGINAL

Claims (7)

Patent application before ΙΊ.), Catalyst for the reforming of hydrocarbons' with water vapor, with a catalyst carrier on the surface of which there is a mixture of nickel oxide and / or nickel together with one or more oxides of uranium, characterized in that the weight ratio between uranium and nickel on the catalyst support 0.62: 1 to 0.74: 1 and the total weight of nickel and uranium on the catalyst support (the nickel being in the oxidized state, ie as NiO) does not amount to more than JO <f »of the weight of the catalyst. 2.) Catalyst according to claim 1, characterized in that the catalyst support is ^ι - alumina · 3 ·) Catalyst according to claim 1 or 2, characterized in that it additionally contains potassium oxide or lithium oxide or compounds which decompose to potassium oxide or lithium oxide when heated. 4 ·) Catalyst according to one or more of claims 1 to 3, characterized in that the total weight of nickel and uranium on the catalyst is 5 to 10 % . 5) catalyst according to one or more of claims 1 to 3, characterized in that the total weight of nickel and uranium is 15 to 20 jfe » 6) A catalyst according to claim 1 or 2, characterized in that the catalyst additionally Bariuinoxyd, Bariwahydroxyd, barium carbonate, Bariumuranat and / or a compound which contains on heating to the above compounds, "substituted, wherein the barium component by impregnating de * Carrier with barium hydroxide or a barium compound, which when heated to barium oxide, barium hydroxide, barium 009841/1811 ORIGINAL BATHROOM '' ■■■ - 11 - carbonate or barium uranate decomposes into the catalyst has been built in, 7.) Catalyst according to claim 1 or 2, characterized in that it additionally contains barium oxide in amounts of not more than 20, wt «- # of the catalyst, the catalyst support by mixing barium oxide or a compound that becomes too when heated barium oxide decomposes, is formed with V the other component or the other components of the catalyst support or with a compound or with compounds which decompose calibrated upon heating to the or the said components, and the mixture thus formed is optionally caleiniert and subsequently like closing the nickel and uranium components of the catalyst are applied to the support surfaces. ί - -. ■ 8 ») Catalyst according to claim 6 or 7, characterized in that that it has 0.7 to 1.5% by weight of the barium component, expressed as Weight of barium oxide, based on the total weight of the catalyst, contains 9 ») Catalyst according to claim 6 or 7, characterized in that that it contains lithium oxide or potassium oxide in amounts of 0.15 to 0.3 wt Alkali metals. , 10 ·) Use of the catalysts according to one or more of the Claims-1 to 5 or 6 or? for reforming hydrocarbons with Vaeser steam. 11 ·) Modification of the catalyst according to claim 6, characterized in that the weight ratio between uranium and nickel on the catalyst support is less than 0.62: 1 or higher than 0.74 t 1 let and / or that the total weight of nickel and uranium on the catalyst support (if the nickel is in the oxidized state, ie as NiO) is greater than 20 wt .- ^ of the catalyst. 009841/1811 BATH Blank page