DE1252181B - Process for reducing the leachability of the alkali or alkaline earth component in a catalyst useful for steam reforming - Google Patents

Description

FEDERAL REPUBLIC OF GERMANY

GERMAN

PATENT OFFICE

EDITORIAL

• 252181

Int.CL:

BOIj

German class: 12 g -11/46

Number:
File number:
Registration date:
Display day:

J 23671IV a / 12 g

May 8, 1963

October 19, 1967

In the German Auslegeschrift 1199 427, the reduction in carbon deposition is on a Described catalyst in a hydrocarbon steam reforming by using a A catalyst comprising an active group VIII metal, a refractory support and an alkali metal compound contains. Under certain operating conditions of such a process, the alkali metal compound are leached from the catalyst, and the resulting loss leads to a less effective in reducing the tendency for carbon to deposit on the catalyst. purpose of the invention, there is now the risk of an undesirable reduction in the life of the catalytic converter to remedy the leaching of an alkali or alkaline earth metal compound from the Catalyst is due.

The invention now relates to a method for reducing the leachability of the alkali and alkaline earth components in a catalyst which can be used for steam reforming and which is an active metal from group VIII of the periodic table, a heat-resistant support material containing one or more acidic or amphoteric constituents and one with Contains water-leachable alkali or alkaline earth compound in an amount of at least 0.5 percent by weight, and is characterized in that the catalyst is heated ^{to a temperature of 600 to 900 ° C. for at least 2 hours before it is used.}

Preferably, the catalyst is heated to 650 to 800 ⁰ C. This heating can be carried out in air, but it is preferred to carry it out in the presence of steam, especially since the catalyst thus prepared shows less shortening of the life after it has been subjected to leaching conditions compared to a similar composition of matter shown in FIG Air has been heated.

In this way the risk of leaching of the alkali metal compound, which can occur under working conditions which exist when using the same in a hydrocarbon steam reforming process, is reduced. When starting up or when carrying out the process, contact of the catalyst with liquid water or moist steam can be unavoidable or difficult to avoid. In using a catalyst prepared in accordance with the present process, the removal of the alkali metal compound is reduced in this way, and usually such catalysts have a longer process for reducing leachability
the alkali or alkaline earth component in one
catalyst useful for steam reforming

Applicant:

Imperial Chemical Industries Limited, London

Representative:

Dr.-Ing. H. Fincke, Dipl.-Ing. H. Bohr

and Dipl.-Ing. S. Staeger, patent attorneys,

Munich 5, Müllerstr. 31

Named as inventor:

George Walter Bridger,

Phineas Davies, Norton-on-Tees, Durham

(Great Britain)

Claimed priority:

Great Britain 11 May 1962 (18 187)

Lifespan than those previously known, which are used under such working conditions, in particular when low steam ratios, for example those of 2, 3 or 4 moles or less of steam per atom of carbon.

Catalysts, which are particularly suitable for the invention, consist of 3 to 80% »preferably 5 to 50 percent by weight nickel, calculated as nickel oxide, a refractory support material (preferably from 95 to 50 percent by weight) and an alkali or alkaline earth metal compound, for example an alkali metal compound which is added as a oxide or hydroxide, in particular a potassium compound in an amount of at least 0.5 weight percent, calculated as Kaliumoxydäquivalent, is present, all percentages being based on the weight of the composition of matter according to an annealing treatment at 900 ⁰ C. The water-leachable alkali or alkaline earth metal compound can be a hydroxide or oxide, or in the case of the alkali metal compounds. also a carbonate. This can be added as such during manufacture. In general, it is preferred that the alkali or alkaline earth metal compound in aqueous solution is alkaline and / or that it consists of a compound which upon heating, for example under the operating conditions of

709 678/403

3 4

Steam reforming to which oxide is decomposed. One mixed with china clay and magnesium oxide,

washed suitable amount of the alkali or alkaline earth metal, dried at 410 to 42O ⁰ C, ground,

compound, in the manner indicated above as mixed with cement, pelletized, with 40% iger

Equivalent K ₂ O calculated, is, for example, impregnated by aqueous potassium hydroxide solution,

1 to 10%. 5 dries and ^{heated to 700 °} C. for 8 hours.

In general, it is preferred that the alkali When testing this heat-treated, potassium

or alkaline earth metal compound in an excess containing catalyst by soaking with water

relative to the amount of acidic or amphoteric at 2O ⁰ C for 12 hours and drying at 100 ⁰ C

Ingredients are present which are acidic, for example, or it has been found that the K _a O content from 8.9 to 7.6%

amphoteric oxides or combinations thereof decreased, ie a 15% loss of K ₂ O occurred

can be with each other, such as aluminum oxide, silicon was. After boiling in water for 24 hours, was

cium dioxide, titanium dioxide, zirconium dioxide, vanadium _{- the K 2} O loss 24%. If the catalyst doesn't

oxide, molybdenum oxide, tungsten oxide, and that has been subjected to such a heat treatment

simple oxides with the alkaline earth metal compounds, the K ₂ O loss was after 24 hours

but also as combinations with alkali metal soaking at 20 ^° C. 50 to 55 "/ 0 ¹¹¹¹ Cl after 24 hours

bonds, such as aluminum silicates (e.g. kaolin), boiling in water 58%. After the heat treatment

Chromium oxide - aluminum oxide, chromium oxide - silicon - the catalyst retains 70% of its strength,

umoxide, chromium oxide - aluminum oxide - silicon- This catalyst was in a steam refor-

oxide, manganese chromate and the like. It is assumed that the mating process is tested as follows:

that the heat treatment to the formation of less 20 47 l / h. a distillation fraction of gasoline,

easily leachable compounds of the alkali or which ^{boil at 35 to 170 0} C, were evaporated in

Alkaline earth metals and such acidic or amphoteric presence of hydrogen to less than 5 parts

Ingredients leads. 'Desulfurized per million over cobalt molybdate, on what

The active metal is preferably one which has been absorbed by the sulfur compounds with zinc-nickel, cobalt, ruthenium, rhodium, palladium, oxide. This fraction was ^{heated to 380 0} C osmium, iridium or platinum, especially mixtures, and mixed with 127 kg of steam per hour of small amounts of one or more (which corresponds to a steam ratio of about 3 mol of steam metals of the platinum group, for example rhodium, per carbon atom) , the vapor being in front of ruthenium or platinum with nickel. had been heated to 400 ^{0 C ago.} This mixture

The catalysts for steam reforming can be fed to a pipe with an inner diameter of usually liquid or gaseous of about 10 cm, which uses 53.5 kg of a hydrocarbons, the steam temperatures produced and treated at the invention up to 35O ⁰ C, preferably contained within the reforming catalyst. During the AnBereiches 30-220 ⁰ C at elevated temperatures running of the reaction, the catalyst appeared to boil. Such a process can be carried out at temperatures 35 of wet steam and the condensation resulting therefrom of, for example, 600 to 1000 ° C, preferably sat in contact. The tube was heated in an oven from 700 to 900 ^° C. at a pressure of, for example, uniformly, so that the temperature of the 1 to 50, preferably 5 to 25, at abs. carried out outlet gas was 806 ⁰ C. The pressure at the outlet, with steam ratios of, for example, the end of the reforming vessel, was 12.3 at abs. 1.5 to 6 moles, preferably 2 to 4 moles, per carbon. 179 m ^{3 of} a gas of the following substance atoms of the hydrocarbon were used per hour. Composition obtained:
However, these processes can also be used at temperatures qq ·, ₅ Q ₀ /

below 700 ⁰ C, for example from 450 to 68O ⁰ C, ^ q 12 4 ° / °

be carried out under conditions in which, inter alia ^, 69 2 ⁰ I

a low steam ratio and an increased 45 /-.jj 34O /

Pressure exist to thereby generate a gas, ⁴ '

which contains a substantial proportion of methane, so after a running time of 269 hours it has

that the product used as town gas base demonstrated that the effectiveness of the catalyst failed

can be. reduced and on it no carbon deposition

B · · 1 1 50 was present. The procedure was then

e ι s ρ 1 e broke and the catalyst on its potassium content

A typical catalyst has, in terms of analyzed, It was found that the content of K ₂ O on

Percentage by weight, the following compositions: the basis given above from 8.9% to 7.8%

O 14 2 had fallen. The greatest amount of potassium was

) ο 252 ⁵⁵ ' ⁿ ^ ^em treated catalyst detained, and the

²³ 110 activity of the same had not decreased.

u'j An examination of the catalyst rings on six

02 showed different levels of the catalyst tube

gQ 0 * 3 ^ ^a ^ ^ ' ^e Strength of the heat-treated cataly-

p _e 0 5Ό ^6o sators was just as good as that of an untreated one

NiO ^Ά ....................... 208 catalyst.

j £ ο 80 Suitable catalyst shapes consist of rings

Loss at 90 ° C 18 ^of ^ ^{mm in} length, 17 mm in outer diameter and

'' 7 mm inner diameter. Such catalyst rings

The catalyst was prepared in that 65 have the advantage of being in spite of the alkali treatment Nickel carbonate from a nickel nitrate solution under and the subsequent heat treatment is used an excess of sodium carbonate speaking strength over a long time in the steam precipitates became. The precipitate obtained was kept reforming.

Example 2

A catalyst consisting of nickel oxide, refractory material with potassium hydroxide, was prepared as described in Example 1. This catalyst composition contained 6.7% K ₂ O and 14.5% SiO ₈ . The weight loss on heating to 900 ^° C. was 14.4%. Samples of this catalyst were each heated for 6 hours in air or in an air-steam mixture (90:10 vol./vol. To 600 to 900 ⁰ C). The efficacy, catalyst life (ie, the time that the catalyst could be kept in use, without that it is clogged by deposited carbon), the compressive strength in the vertical direction catalyst surfaces and loss of K ₂ O in cooking for 24 hours at 100 ⁰ C in water are summarized in the following table.

The investigations regarding the effectiveness and the service life were carried out by reforming a light gasoline distillate with a boiling range from 38 to 170 ⁰ C, namely as follows:

1. In the effectiveness studies, a temperature of 500 ⁰ C was first used

IO a space velocity of a liquid hydrocarbon of 1 Vol./Vol./Std., A steam ratio of 2.5 and secondly a temperature of 600 to 700 ⁰ C at a space velocity of the liquid hydrocarbon of from 2.5 Vol./Vol./Std ., worked at a steam ratio of 5 moles of steam per carbon atom, each time under atmospheric pressure. 2; In the durability tests of the liquid hydrocarbon of 9 Vol./Vol./Std was at a temperature of 600 ⁰ C, at a space velocity. Worked a steam ratio of 2 and at atmospheric pressure.

The horizontal compressive strength corresponds to the radially applied pressure in kilograms that is required is to a single granulate of the catalyst in question 3.6 mm long and 5.4 mm in diameter to crush. The vertical compressive strength

ao is similar to the applied axial force required to crush such a granulate. The catalyst surface is given in square meters per gram.

working conditions

sample

Heating temperature / gas present

% K ₂ O washed out at
100 ⁰ C in 24 hours ...

Effectiveness (% hydrocarbon converted)
before 24 hours of washing treatment

500 ° C

600 ⁰ C

700 ⁰ C

Lifespan in minutes
at 600 ⁰ C before clogging of the catalyst

a) before washing ...

b) after washing ..

Horizontal compressive strength, kg

Vertical compressive strength,
kg

Catalyst surface area, m ^a / g

100

240+ 15

530 8.4

600 ° C / air

24

68

70

200

240+ 21

59

590 24.6

700 ⁰ C / air

20th

66 58 98

240+ 150

42

430 21.4 800 ° C /
air

12.5

62
54
94

240+
240+

44

420
17.3

900 ° C /
air

600 ° C /

Air and air and air and air steam

42
32
70

240+
240+

31

380
7.12

21

66

76

100

240+
240+

57

525
37.9

700 ° C /
Air and steam

64
74
96

240+
240+

470
32.9

800 ⁰ C / air and steam

12.5

68 64 97

240+ 240+

44

455 29.5

900 ⁰ C / and steam

10

68 64 93

240+ 240+

28

395 13.07

Claims (3)

Patent claims: 1. A method for reducing the leachability of the alkali or alkaline earth component in a catalyst which can be used for steam reforming and which is an active metal from Group VIII of the Periodic Table, a heat-resistant support material containing one or more acidic or amphoteric constituents and one with Contains water-leachable alkali or alkaline earth compound in an amount of at least 0.5 percent by weight, characterized in that the catalyst is heated ^{to a temperature of 600 to 900 ° C. for at least 2 hours before it is used.} 2. The method according to claim 1, characterized in that the heating in the presence of Steam performs. 3. The method according to claim 1 or 2, characterized in that it is heated ^{to 650 to 800 ° C.} Documents considered: German Auslegeschrift No. 1110 807.