DE2328064B2 - HYDROCARBON STEAM REFORMING CATALYST - Google Patents

Description

2. Use of a catalyst according to claim 1 for hydrocarbon steam reforming.

Carbon of the supplied hydrocarbons, hereinafter referred to as "CO ₂ / C"), and therefore the desired gas, e.g. B. hydrogen gas, fuel gas or various synthesis gases can be obtained.

The most important problem when using the steam reforming catalyst is that of carbon separation on the catalyst, although it depends on the particular conditions when hydrocarbons react with steam.

The main reactions leading to carbon deposition are given by the following equations:

CmHn »C + Cm'Hn '+ H ₂ (5)

2CO -C-I-CO, (6)

The steam reforming response can be expressed by the following equations if one Hydrocarbons of the formula CmHn supplies:

The carbon deposition on the catalyst causes a decrease in the activity of the catalyst, however, the problems are even more serious

Pulverization and the disintegration of the catalyst through

carbon deposition as well as the inevitable subsequent interruption of operation due to the

The invention relates to a hydrocarbon plugging of gas lines.

material steam reforming catalyst. Currently, To prevent this carbon deposition,

Hydrocarbon steam reforming processes in which H ₂ O / C is usually increased. An increase in the production of hydrogen gas, fuel gas or H ₂ 0 / C can make the carbon deposition on the various synthesis gases predominant. Suppress the catalyst, but this leads to the steam reforming of hydrocarbons, on the other hand, to the consumption of the supplied substances, usually by passing through the hydrocarbon fuel, etc., and therefore the increase in the substances, especially paraffinic hydrocarbons, is in gas H _: O / C uneconomical.

shaped state together with steam through in As known catalysts with a sub-unit Heat-resistant cylinder filled with catalytic converting effect on carbon deposition catalysts at a temperature of 400 to 800 ° C and 35 catalysts were previously available, the Nicke! as a pressure of 1 to 30 at. Main component and potassium as a catalytic fuel

on a heat-resistant oxide support aufsisen (US-PS 13 34 055, US-PS 33 94 086). These Catalysts prevent separation of the active substances formed during the reforming of the hydrocarbons Carbon than stable carbon. Now potassium tends to migrate through the catalyst and to evaporate due to its low boiling point. As a result, the catalyst condenses evaporated potassium and separates on low-temperature parts downstream of the steam reforming plant from, whereby it unfavorably clogs the pipe system.

In addition, there were already catalysts that used nickel

thermal decomposition and hydrogenation, and the 50 and uranium on a heat-resistant oxide carrier Product mainly consists of water retention (Jap. Pat. Publ. 7708/68, 4454/71, 25366/71,

25367/71). These catalysts promote the reaction of the deposited on the catalyst during reforming active carbon with water to form hydrogen gas and carbon monoxide you however, they are only used to a limited extent as it acts as a catalysis promoter Uranium is a radioactive element.

Hydrocarbon steam reforming (10 Catalysts made from a heat-resistant oxide carrier with nickel as a main catalytically active

CmHn + mH ₂ O ~> mCO

CmHn + 2mH ₂ O- »mCO,

(2m + -JH ₂

(D

(2)

The reaction process includes in addition to the reaction equations given above

p r

substance, carbon monoxide, carbon dioxide, methane and water vapor. A relationship between these components can be expressed by the following equilibrium equations:

CH ₄ + H ₂ Of = ^ CO + 3H ₂

CO + H ₂ O.

-CO ₂ + H ₂

The equilibrium composition of the gas produced depends on the temperature, pressure and proportions of the substances fed in (steam / oil ratio: ratio of the steam molc per gram atom of carbon of the (, 5 hydrocarbons, hereinafter referred to as "H ₂ O / C"; Carbon dioxide-carbon ratio: ratio of the moles of carbon dioxide per gram-atom

tive constituent and 2 to 49% by weight of silver as catalysis promoters known, which are obtainable by firing a shaped mixture of the powdery, heat-resistant oxide carrier with nickel and silver compounds (GB-PS 10 32 754). When they are used, the H ₂ O / C ratio is at least 1.3, and the potassium alloys should preferably

Sators still contain an alkali metal , which brings the disadvantages mentioned.

A similar catalyst with 1 to 10% by weight of nickel and 0.01 to 10 % by weight of silver in a porous support is also known for hydrocracking (US Pat. No. 2,926,130).

The most important requirement for the steam reforming catalyst, that one can thereby prevent the catalyst with the lowest possible ratio of VL ₂ OJC carbon deposition. In addition, it is very desirable that the steam reforming catalyst can perform this function with different types of hydrocarbons, that is, with both paraffinic and olefinic hydrocarbons. Furthermore, such a catalyst should have excellent activity in a wide range of temperatures and pressures. In addition, the steam reforming catalyst should have high heat resistance and mechanical strength, so that it can withstand higher temperatures and pressures.

The invention is therefore based on the object of a hydrocarbon steam reforming catalyst indicate which meets all these requirements better than the known catalysts.

The invention, with which this object is achieved, is a hydrocarbon steam reforming catalyst from an oxide carrier in the hilly region with nickel as a main catalytic active ingredient and silver as a catalyst promoting agent, obtainable by firing a molded mixture of the powdery refractory oxide carrier with nickel and silver compounds, with the sign that the catalyst has a nickel group, calculated as NiO, from 10 to 30% by weight, at least 2 mgAtomc silver per 100 g of catalyst and at least a rare earth element in an atomic ratio of the rare earth element or elements to silver of 0.2 contains up to 2.0.

The raw materials for nickel that are used in the invention Catalyst used as the main catalytically active ingredient include, inter alia. Nickel oxide, nickel nitrate, nickel carbonal, nickel oxalate, nickel formate.

The raw materials for silver, used in the steam reforming catalyst according to the invention as a catalyst promoting agent serves include, inter alia. Silver oxide, nitrate and carbonate.

As a rare earth element that is used in the invention Catalyst as an additional catalyst promotion agent can serve, lanthanum, ccr, yttrium, praseodymium. Use neodymium, etc. Lanthanum graze, taking into account availability and costs. cerium and yttrium preferred. Mixtures of sell-earth elements can also be used obtained from Monazite, Xenolim, Baslnaesit, etc. As raw materials, these rare earth elements. that too Should be borne by the heat-resistant oxide, they are mainly oxides and nitrates. Carbonates. Use hydroxides and oxalates.

The best / most changeable oxides used in the dump reforming catalyst according to the invention include the oxides of aluminum. Sili / iiim. Magnesium. Titanium. Zircon. Beryllium. Thorium. The help-resistant oxide can be in any shape. /. I). kugellormi ;. ¹ .. cylindrical. slüek-shaped <ulei be powdery. Generally, carbon precipitates when acidic oxides, such as /. B. alumina.

Silica, etc. are used as a carrier, lighter, but the analyzer composition according to the invention has been found to have the Even then, hold back the carbon separation considerably can when these acidic oxides are used as carriers.

If silver is present in an amount of less than 2 mg of atoms per 100 g of the catalyst, the suppressing effect on carbon deposition is unsatisfactory, and the rate of carbon deposition exceeds 40 mg / h at the usual rate of supply of hydrocarbons, unless the ratio H ₂ OC is set higher than 3. As a result, the operation of the steam reforming plant is disrupted. The amount of silver can be increased well over 2 mgAtome (per 100 catalyst) as long as the main catalyst component, nickel, can be kept above its lower limit.

The reasons for the effect of silver as a calcium enhancer in terms of suppressing carbon deposition have not yet been clarified, but silver can if silver salt compounds supported by a refractory oxide, apparently the reactivity between the active carbon and improve steam.

Furthermore, the rare earth elements are alkaline substances and have a good affinity for acidic metal oxides, such as ζ B. aluminum oxide and silicon dioxide. Therefore, the rare earth element can be found in alumina or silicon dU'Ud adhere sufficiently and the surface of the aluminum or silicon oxide convert to an alkaline behavior, thus apparently the suppressing effect on carbon separation is improved. They also have Oxides of the rare earth elements have good heat resistance, and it appears that the rare earth elements have the Improve the heat resistance of the catalyst and prevent its deterioration by heat.

The steam reforming analyzer according to the invention is produced as follows: A Mixture of water-soluble compounds of nickel, silver and metal elements. the one another in the above ranges are mixed with powders of refractory oxides mixed in the dry or muddy state, and the obtained mixture becomes theirs intended shape and fired, whereby the desired catalyst is obtained. No differences are observed in the behavior of the catalyst, whether one uses the silver compound and mixing the rare earth component simultaneously or sequentially or in stages.

The catalyst thus obtained can be used for steam reforming a wide range of hydrocarbons including methane and exhaust gases from various hydrocarbon materials. As a liquefied natural gas hydrocarbons, hydrocarbons with higher Molekularge ^M ichlen than that of methane, such as liquid hydrocarbons, liquefied petroleum gas, butane. Hexane, petroleum corpse distillery and naphtha can be used.

The hydrocarbon quantity is at the same time mil Steam passed over the catalyst and can be in a temperature range of 350 to 900 C. and reform in a pressure range from 1 to 50 kg / cnr.

If hydrocarbons with more than 1% olefin hydrocarbons are steam reformed over the catalyst according to the invention, the carbon separation is only 2 mg / h or less, even if the ratio of H ₂ OC is only 0.75 in each case If the raw material is steam reformed over the conventional catalyst, the exhaust gas must first be passed over a hydrogenation catalyst in order to convert the olefin hydrocarbons into paraffin hydrocarbons and thus prevent excessive carbon deposition. When the feed gas is passed over the hydrogenation catalyst, the temperature of this gas rises due to the hydrogenation reaction and the activity of the hydrogenation catalyst is lost to a noticeable extent. Therefore, there has hitherto been a mandatory limit on the content of olefinic hydrocarbons in the feed gas.

With the catalyst according to the invention, however, you can use a feed gas with a content of steam reforming about 15% by volume of olefin hydrocarbons directly without the occurrence of any disturbances, without the gas previously being passed over the otherwise customary hydrogenation catalyst layer. So you can see the construction costs of the reforming plant and make their operation much easier.

At a ratio of H ₂ O / C of 3.0, the carbon deposition can be reduced to 5 mg / h or less, despite the said content of olefin hydrocarbons.

When the catalyst activity in proportion to the feed rate of carbon, d. H. as the number of gram atoms of carbon per unit volume of the catalyst is expressed per unit time of supplied hydrocarbon, can the proportion of unreacted hydrocarbon z. B. in the case of η-butane at 55 g atoms of carbon each Maintain 0.01% or less per hour and liter of catalyst. Therefore, the invention Catalyst apparently a practically very satisfactory activity.

The catalyst of the present invention is useful as a steam reforming catalyst for generating hydrogen gas, methane-rich fuel gas or various synthesis gases for methanol synthesis, oxo synthesis, etc., and can be used directly for steam reforming a starting gas containing olefins. Furthermore, the catalyst according to the invention can also be used at a low H ₂ O / C ratio and can therefore be used to generate gas for ore reduction. In addition, the catalyst of the present invention has a good suppressive effect on carbon deposition and can therefore be arranged at a plant part where carbon tends to be deposited in the steam reforming plant, that is, usually at the inlet part.

The invention will now be based on exemplary embodiments with reference to the drawing be explained; in it shows

F i g. 1 shows a diagram to explain the relationships between H ₂ O / C ratios and carbon deposition when, according to one embodiment, η-butane is steam reformed over the catalyst according to the invention,

F i g. Fig. 2 is a diagram for explaining the relationship between the ratio La / Ag and the Carbon deposition if, according to another embodiment, n-Bulan over the inventive Catalyst is oxo-reformicrt, and

F i g. 3 is a diagram for explaining the relationships between ethylene concentrations and the Carbon deposition. if after a further Ausrührungsbeispiel ethylene containing ethane over the catalyst according to the invention is steam reformed.

B e i s ρ i c 1 I

Catalysts according to the invention and comparative catalysts were prepared in the following way:

Catalyst A (inventive catalyst)

75.0 g of nicole nitrate hexahydrate, 9.3 g of lanthanum nitrate hexahydrate and 3.67 g of silver nitrate were separately dissolved in water, and the three obtained aqueous ones Solutions were mixed with each other to make a total volume of 70 ml. 100 g of spherical active alumina carrier material with grain sizes from 1.68 to 2.82 mm impregnated with the resulting mixed solution and dried at 110 C for 3 hours and then at Fired at 900 C for 2 hours.

The catalyst obtained contained 15.4% by weight of nickel as NiO and 17.2 mg of Alome lanthanum per 100 g Catalyst (21.6 mg atoms of lanthanum per 100 g of the carrier material) and had an atomic ratio of lanthanum to silver of 1.0.

Catalyst B (comparative catalyst)

75.0 grams of nickel nitrate hexahydral and 7.34 grams of silver nitrate were separately dissolved in water, and the two aqueous solutions obtained were taken under Get a total volume of 70 ml mixed together. 100 g of spherical active Aluminum oxide carrier material with grain sizes of 1.68 to 2.82 mm were mixed with the resulting mixed solution impregnated, dried for 3 hours at 110 ° C and baked for 2 hours at 900 ° C.

The catalyst obtained contained 15.5% by weight of nickel as NiO and 34.7 mg of silver atoms per 100 g of des Catalyst.

45 Catalyst C (comparative catalyst)

75.0 grams of nickel nitrate hexahydrate and 18.7 grams of lanthanum nitrate hexahydrate were separately dissolved in water, and the two aqueous solutions obtained became

mixed with one another while maintaining a total volume of 70 ml. 100 g of spherical active aluminum oxide carrier material with grain sizes from 1.68 to 2.82 mm were impregnated with the resulting mixed solution and ^{dried at 110 °} C. for 3 hours

and then fired ^{at 900 °} C. for 7 hours.

The catalyst obtained contained 16.2% by weight of nickel as NiO.

Catalyst D (comparative catalyst)

75.0 grams of nickel nitrate hexahydrate and 18.7 grams of lanthanum nitrate hexahydrate were dissolved separately in water, and the two aqueous solutions obtained were mixed together to make a total volume of 70 ml. 100 g of ball

shaped active aluminum oxide carrier material with grain sizes from 1.68 to 2.82 mm were used with de The resulting mixed solution is impregnated, dried for 3 hours at <110 ° C. and baked at 900 ° C. for 2 hours

5

The catalyst obtained contained 15.3% by weight Nickel as NiO and 34.2 mg Alome Lanthanum per KK) g catalyst.

25 ml of each of the prepared catalysts were each in a reaction tube with an inner diameter given by 15 mm, the catalyst layer temperature was set to 600 C or more at the entrance and 800 C or more at the exit elevated. Hydrogen was passed through this reaction tube at a flow rate of about 300 ml / min together with steam for 1 to 2 hours to reduce the catalysts. Then the catalysts were used for the experiments.

The experimental reaction was carried out in each case by keeping the inlet and outlet temperatures of the catalyst layer at certain values, adjusting the feed rates of η-butane, steam and carbon dioxide so that the ratios of H ₂ OIC and CO ₂ / C assumed certain values, and the starting materials passed through the reaction tube after passing through a preheating section, the reaction being initiated above the catalyst. The reaction product gas was sent to an analyzer through a condenser and a trap, and an overall analysis of the reaction product gas for its components other than water was carried out by gas chromatography.

The amount of carbon deposits was determined by looking after the completion of the experimental reaction the Kalalysatorschichl supplied oxygen to so the deposited carbon in To convert carbon dioxide. The carbon dioxide obtained was then measured quantitatively.

If tests were to be carried out over the same catalyst while changing the ratios of H ₂ O / C and CO ₂ / C, the catalyst was reduced again and then used for the further tests.

In Fig. 1 shows the relationships between the H ₂ O / C ratio and the amount of carbon trapping in the steam reforming of η-butane under atmospheric pressure for each of the aforementioned catalysts A to D. The steam reforming conditions according to FIG. 1 were the following:

Starting temperature of the

Catalyst layer 730 to 800 ° C

Amount of catalyst 25 mi

Response time 1 hour

Test pressure atmospheric pressure

1 η of the following Table 1 are the test data and results are given, including data when elevated pressure is applied.

Table 1 H ₂ O ¹ C CO ₁ C pressure Catalysis
sator
layer-
initial
tempe-
rature Reaction product gas composition
H ₂ CO CO ₂ CH ₄ QH / 10 15.9 12.1 0.91 <0.001 Coal loading
stumbling block
away
divorce Kalaly coals
sator sto (T-
feeding
speed
digkeil ·) (kg cm ² } CC) 3.4 19.7 19.3 <0.001 (mg / h) 3.07 0.0 1.0 830 71.1 3.9 19.5 29.3 <0.001 A 55.1 3.06 0.0 1.0 508 57.6 6.1 64.9 13.5 <0.001 54.4 3.01 0.0 15th 595 47.3 13.9 11.0 4.3 <0.001 32.5 3.01 2.95 15th 590 15.5 23.0 44.8 2.7 <0.001 32.5 3.00 0.0 15th 785 71.0 19.6 6.3 14.5 <0.001 56.7 3.00 2.35 15th 744 29.5 34.5 22.5 4.7 <0.001 56.7 1.18 0.0 15th 820 59.6 16.5 11.5 0.12 <0.001 1.2 32.4 1.20 1.20 15th 800 35.3 3.7 20.3 16.5 <0.001 1.5 32.4 2.89 0.0 1.0 842 71.8 2.7 17.4 31.2 <0.001 B 56.2 3.00 0.0 1.0 535 59.5 13.7 11.2 4.2 <0.001 59.0 3.01 0.0 15th 557 46.7 23.1 45.9 1.3 <0.001 32.6 2.97 0.0 15th 784 70.9 20.7 5.7 13.7 <0.001 57.0 2.99 2.93 15th 743 29.7 35.2 22.0 4.1 <0.001 56.8 1.19 0.0 15th 815 59.9 17.5 10.6 0.06 <0.001 7.5 32.7 1.19 1.22 15th 803 38.7 3.88 20.0 17.7 0.175 9.1 32.3 2.89 0.0 1.0 840 71.8 2.70 18.8 29.5 0.023 C 59.2 2.92 0.0 1.0 570 58.3 6.80 65.7 11.7 0.036 56.1 3.02 0.0 15th 599 49.0 13.8 11.2 3.6 0.004 32.5 3.02 3.06 15th 591 15.8 23.1 45.7 1.65 0.011 32.5 3.05 0.0 15th 790 71.4 20.3 5.8 13.9 <0.001 56.5 3.05 3.01 15th 741 29.6 35.1 22.1 4.31 0.003 56.5 1.19 0.0 15th 515 60.0 110.9 0.2 kg * 32.5 1.20 1.23 15th 799 38.5 127.2 0.5 cnr 32.4

·) GAtomc Cl) I catalyst.
**) Pressure difference between upstream and downstream of the catalyst layer.

709 517)

5 Vi, '. "

ίο

continuation

Cataly- carbon- H ₂ OZC
salor sloff-

feeding

gcschwin-

age *)

CO ₂ ZC

Pressure catalytic reaction product gas / composition carbon Bc-

Sator- (vol .-%) sloff- remark

shift

output H ₂ CO CO, CM, C ₄ 11/10 separation

temperature

(kg / cm ² ) ('C) (mg / h)

55.6 2.99 0.0 1.0 335 72.2 16.1 11.7 0.05 0.027 58.9 2.83 0.0 1.0 533 58.5 2.91 20.7 17.6 0.397 32.5 2.99 0.0 15th 576 44.7 2.00 19.3 33.9 0.057 32.5 2.99 3.09 15th 578 14.3 5.40 67.4 12.7 0.186 57.6 2.99 0.0 15th 789 70.9 13.6 11.5 4.07 0.008 57.6 2.99 2.86 15th 762 29.9 22.9 44.9 2.16 0.036 32.6 1.20 0.0 15th 798 58.2 19.2 0.70 15.8 0.017 39.6 32.6 1.18 1.19 15th 785 36.5 33.2 23.9 6.42 0.049 101.1

·) GAtome C / h · I catalyst.

It can be seen from the test data in Table i that catalysts B, C and D (comparative catalysts) have a somewhat higher concentration Resulting residual butane and thus a somewhat lower catalytic activity than the catalyst A according to of the invention. Catalyst A provides a low concentration of residual butane, with the reaction product gas has a composition almost identical to that of the equilibrium composition which means that the catalyst has good catalytic activity over a wide temperature range having.

Catalyst A according to the invention also shows 40 g a noticeably lower carbon deposition than catalysts B, C and D (comparison catalysts) and hence a good carbon deposition suppressing effect. One foresees this mainly from the test results at atmospheric pressure in Fig. 1.

Example 2

5 °

Catalysts were prepared in a manner similar to Example 1, with the atomic ratio being was changed from lanthanum to silver and there were suppressing effects on carbon deposition examined.

The molar ratios of lanthanum nitrate to silver nitrate were set to 100: 0 (catalyst D), 95: 5, 80:20, 65:35, 50:50 (catalyst A), 35:65, 20:80, 5:95 and 0: 100 (catalyst B) set, but the total amount of atoms of lanthanum and silver per 100 g of carrier material was constant at 43.2 mg of atoms held.

An Oxoreformierreaktion of n-butane with 25 ml of catalyst material at an outlet temperature of the catalyst of 785 to 825 ^D C., a pressure of 15 kg / cm ² and with ratios of H ₂ O / C and CO ₂ IC of about 1 was carried out. 2 was carried out in a manner similar to Example 1, and the carbon deposits were determined. The reaction time was 1 hour and the carbon feed rate was 32 to 33 gAtom C / h x 1 catalyst. The results are shown in FIG. 2 summarized.

If the atomic ratio of lanthanum to silver becomes too large and you become the catalyst of the Composition nickel - lanthanum - aluminum oxide, d. H. D approaches, the suppressive effect decreases the carbon deposition, and also the catalyst activity decreases. Therefore the catalysts should according to the invention are prepared and composed so that the atomic ratio of the rare earth element content to silver ranges from 0.2 to 2.0.

Example 3

Aluminum nitronahydrate, nickel nitrate hexahydrate, lanthanum nitrate hexahydrate and silver nitrate were weighed in amounts by weight as shown in Table 1 and separately dissolved in water. The aqueous solutions obtained above were mixed with each other to make the total volume 21, and then ammonia water egg was added dropwise to precipitate precipitates. After settling, the supernatant was removed by decantation. Distilled water was then added to the precipitated residue, and the mixture was stirred and decanted. This process step was repeated twice, and then the solid residue was filtered off. The residue was then 10 hours at 110 "C getrockne and pulverized. The obtained powders were mixed mv 2 wt .-% of polyvinyl alcohol and then mm to form tablets having a diameter of 10 and a thickness of 5 mm under a pressure of 500 kg / cm ^2. The tablets obtained were calcined at 900 ° C. for 2 hours and used as catalysts.

5

Table 2

12th

Kalalysalor Aluminum Nickleiral Laminine Nilrate niliat

Silver nitral NiO

Kicw .- 'M ((Il-W.- ",,)

La

Kiev .- ",,,)

Ag (mgAtome / K) Oe catalyst)

563.1 75.0 0.48 0.19 19.3 80.4 561.0 75.0 0.95 0.37 19.3 80.1 556.8 75.0 1.86 0.73 19.3 79.5 521.9 75.0 9.35 3.67 19.3 74.5 478.4 75.0 18.70 7.34 19.3 68.3 391.5 75.0 37.91 14.68 19.3 55.9

2.2

4.3

21.6

43.2

86.4

2.2

4.3

21.6

43.2

36.7

The catalyst activity and carbon deposition became similar for these catalysts E through J as measured in Example 1, and the influences of the amounts of the lanthanum and silver as catalysis promoters were examined. The results are given in Table 3.

Table 3

catalyst

Cabbage

material-

feeding

gcschwin-

digkcil *)

H ₂ OC CO ₂ ZC pressure

Kalaly-

sator

layer-

atisgangs-

lempc-

rature

(kg curl I C) Reaction product gas composition (Vol .-% \

H ₂ (Ό CO, CH ₄ C ₄ H 10

Carbon separation

(mg / h)

32.6
32.4
32.4
32.5
32.4
32.6

1.21
1.18
1.18
1.20
1.19
1.20

1.23 1.20 1.21
1.17 1.24 1.27

15 15 15 15 15 15

803 801 805 796 800 789

36.5 36.9 37.2 36.8 37.2 36.5

32.0 33.1 33.6 32.5 33.3 31.2 25.1
24.9
24.3
25.0
24.3
26.0

6.4
5.1
4.9

5.7
5.2
6.3

0.005

<0.001

<0.001

<0.001

<0.001

<0.001

31.6 7.5 3.6 1.2 1.8 1.9

*) gAtomc ChI catalyst.

As Table 3 shows, the reaction product gas composition is almost identical to the equilibrium composition, and accordingly good catalyst activity was achieved. The amount of Carbon deposition decreases with an increase in the contents of lanthanum and silver, and it does it is necessary that at least 2 mg atoms of silver are present per 100 g of catalyst. It is also desirable that at least 2 mgAtome lanthanum per 100 g of catalyst are present, so that the good The effect of the lanthanum stops.

Example 4

The reforming of methane containing olefin hydrocarbons was carried out using catalysts A to D according to Example 1 in order to make further comparisons of the behavior of the catalysts. The test gas that was processed here was a gas mixture of methane. Ethylene and hydrogen, in which the ethylene concentration was varied in a range from 0 to 1.7% by volume, while the partial pressure of hydrogen was fixed at 15% by volume and the remainder each consisted of methane. The test gas was passed over the catalyst together with steam at an H ₂ O / C ratio of 3.0, and the reaction was carried out with ml of each of the catalysts A to D under the following reaction conditions similar to Example 1:

Pressure 8 kg / cm ²

Catalyst bed inlet temperature 500 ° C

Catalyst layer outlet

temperature 750 "C

Response time 1 hour

Carbon feed rate 30 g atoms

CIh · 1 catalyst

The relationships between the ethylene concentration and the carbon capture were determined and the results are shown in FIG. 3 illustrates.

ho F i g. 3 shows that the amount of carbon deposition with an increase in the ethylene concentration in the case of catalysts 3, C and D (comparison catalysts) grows and is obviously influenced by the ethylene concentration, while irr

f> 5 case of the inventive catalyst A prak The table shows no influence of the ethylene concentration. Therefore, if the invention Gas reforming catalyst is used

5

With ^height-r he concentration containing starting gas out of a steam reformer olefin hydrocarbons without any pre-treatment in a hydrogenation reactor directly.

Catalyst L

Example 5

Catalysts according to the invention were produced as follows:

Catalyst K

75.0 g of nickel nitrate hexahydrate, 3.67 g of silver nitrate and 5.8 g of a mixture of rare earth elements obtained from monazite sand were separately dissolved in water, and the resulting three aqueous solutions were mixed together to make a total volume of 70 ml to obtain. 100 g of spherical active alumina carrier material with sizes from 1.68 to 2.82 mm were impregnated with the obtained mixed solution, 3 hours at 110 ⁰ C dried and fired for 2 hours at 900 ° C.

The catalyst obtained contained 15.5% by weight of nickel as NiO, 17.2 mg of atoms of silver per 100 g of catalyst (21.6 mgAtome silver per 100 g of the carrier material) and 6.8 mgAtome lanthanum, 10.8 mgAtome "he 2.9 mg of atoms of neodymium and a small amount of praseodymium, samarium, etc. per 100 g of catalyst.

Table 4

The catalyst was prepared in the same way as the catalyst K with the exception that the Rare earth element mixture of the catalyst K was replaced by 9.38 g of cerium nitrate hexahydrate.

The catalyst obtained contained 15.4% by weight of nickel as NiO, 17.2 mg of atoms of silver per 100 g of catalyst (21.6 mg atoms of silver per 100 g of the support material) and 17.2 mg of atoms of cerium per 100 g of catalyst.

Catalyst M

The catalyst was processed in the same way as the

is catalyst K with the exception that the The rare earth element mixture of the catalyst K was replaced by 8.27 g of yttrium nitrate hexahydrate. Of the

The catalyst obtained contained 15.4% by weight of nickel as NiO, 17.2 mg of atoms of silver per 100 g of catalyst

(21.6 mg of atoms silver per 100 g of carrier material) and

17.2 mg of yttrium atoms per 100 g of the catalyst (21.6 mg of yttrium atoms per 100 g of the support material).

The amount of carbon deposition was determined for

the catalysts K, L and M according to the

game 1 explained procedure intended to

their carbon deposition suppressing effects to check. The results are given in Table 4.

catalyst

Cabbage

material-

supply

gcschwin-

digkcit *)

32.5
32.4

32.4
32.6

32.3
32.5

H ₂ CVC CO ₂ JC

pressure

Catalysis

sator

layer-

initial

tempc-

rature

Recognition product gas composition (VoL- ¹ VO)
H ₂ CO CO, CH ₄

(kg / cm ² ) ("C)

Carbon lab-QH / IO separation

(mg / h)

1.20
1.22

1.19
1.18

1.19
1.20

0.0
1.25

0.0
1.19
0.0
1.21

15.0
15.0

15.0
15.0

15.0
15.0

801
785

793
788

800
791

19.3
32.8

19.4
32.7

19.4

33.3

6.7
24.2

6.9

24.1

7.0
23.7

15.9
6.4

15.7
6.9

15.1
6.5

0.001

<0.002

<0.001

<0.002

0.001
0.001

3.5
7.1
1.8
3.9

5.1
4.7

*) gAlomc C / h ■ I catalyst.

It can be seen from Table 4 that the catalysts, if they are not only lanthanum, but also Cerium, yttrium or a mixture of rare earth elements as catalysis promoters together with contain the silver on the support material, have a good catalytic activity and a good suppressing effect on carbon deposition. Further, it should be noted that a good carbon deposition suppressing effect can also be obtained leaves, if a mixture of rare earth elements obtained from monazites, xenotimes, bastnaesites as rare earth element content is used.

For this purpose 3 sheets of drawings

Claims (1)

Patent claims: 1. Hydrocarbon steam reforming catalyst made of a refractory oxide support with nickel as a main catalytically active one Ingredient and silver as a catalysis promoter, obtainable by firing a shaped Mixture of the powdery, heat-resistant oxide carrier with nickel and silver compounds, characterized in that the catalyst has an amount of nickel, calculated as NiO, of 10 to 30% by weight, at least 2 mg atoms of silver per 100 g of catalyst and at least one rare earth element in an atomic ratio the rare earth element or elements in silver contains from 0.2 to 2.0.