DE1767516C3 - Process for the preparation of a catalyst for the steam reforming of hydrocarbons - Google Patents

Description

at

Reduce the space velocity of the-; Is there no noticeable effect on the % &%? E <can be any Nickeliak ^ _{w rden} by hydrogen

decomposed from 40o 'to 700 ⁰ C and ^^. ^ _{metallic nickel}

^ S _{e are} inorganic salts such as nickel bidet · »£ ρ.β _{ixhfS Nicke} lcarbonat, N.cxel-

N ckeicai ^D ° ⁿ ', _{t etc. or} organic nickel hydroxide K.ekel y _{Njckelformiati Nicke} l _a cetat

salts, like _{kel connections} are dried,

etc. υ e * _closed completely with cement

^Powder *! ^ert "" J ^ Lr the addition of water the · ' _forms and hardened. It is also possible to simply shape and harden and to -... ^^ _η "solution of a nickel compound on flowing e» «* _{and the} same herewith

the "men 5 ^ _{stuck cement with} nickel

The invention relates to a method for producing a catalyst which is a nickel compound and Contains cement, for the steam reforming of Hydrocarbons, in which a mixture of the nickel compound and the cement is heated.

In a number of processes for the production of gaseous starting materials for d.e methanol or Ammonia synthesis or town gas production

those hydrocarbons of steam reforming are subjected, there is a risk of d, e carbon deposition increases as the molecular weight of the hydrocarbon feedstock becomes higher, d. H. the boiling point of the starting materials increases. Another reason is that the proportion of unsaturated components is also higher.

The object of the invention is to provide a method for production of a catalyst with a simple structure for the steam reforming of hydrocarbons show in which no carbon deposition be. the steam reforming occurs. .

This object is achieved according to the invention in a method of the type mentioned at the beginning that the mixture, which 3 to 40 weight proofs Contains nickel, under the action of a hydrogen gas stream, which contains less than 10% hydrocarbon, Contains carbon dioxide and carbon monoxide, heated at a temperature of 400 to 700 ° C

The invention then also proves to be advantageous. detention, if the starting materials contain a high proportion of unsaturated components.

The nickel, which has a catalytic effect the steam reforming of hydrocarbons wields is metallic nickel which is fine on the Catalyst support is dispersed

If in the catalyst preparation the temperature is lower than 400 ⁰ C, the decomposition of the nickel compound is not complete and a sufficient activity can not be obtained when the temperature is higher ah 700 ^B C. connects to the nickel with the support and it imagines Spinel, or silica cement, is used.

It is sufficient if the nickel compound in an amount ir »ι τ, ° / (based on the weight of the finished _product from meu as J /“ K b below, if not

indicated, always the case). gs ^^ ^ ^^ _{basjert a (jf}

The «mm ^ ^ _{favored Nic} kcl salary

S'Sjen 5 to 30%. Because of the advancing cherishes ^ 'sdien. "/ ^ _{by traces of} sweat

_in the hydrocarbon Aussind is _preferably heavier ^ X _as starting materials a Kataly-JNW ^ rs ^ _{u. Bci Koh} .

sator in the raw 8 ^ ^ ^ ^^ ^

len »assc ^ ^st ™ ' _{u with a nickel} content of more than

^ m ^K ataWsator m. _Was _ _{erstoffstronl) der zur Re} .

20, bcvorz g ^ _Nicke i _ve used rbindung

Ju ^ ion gaseous components

_{will contain} oll kernels β . Gas transport

al s.ner f ^ '^ ² ^ hydrocarbons, CO,

rage V «unre.n, g · J> ^ _{The content of un} .

^ J ^; ^S ^ _shaped impurities must be less

■ preferably less than 5%, than JO / ^ ugs _nick ^ _{oil connection m} ; _t cement

and then a thermal treatment at the same time

f ^, ^ exposed to _{raw material flow.} However, it ^may "" ^^ Vormen and hardening of the cement ^ ^ch ^ ^ ^cll _ei ^em _{N [ckelverbindung} be impregnated,

Thermal decomposition and reduction can _{then be carried out} .

f _g ^{e C} '™ _treatments the catalyst becomes very

«Effective surface of the catalyst

porous Jd £ e * «Ks _oh , _{bkibt the mecha} .

^^ tSince the catalytic converter is very high, the ^ Strength ^ a ^ J ^^ is _suitable . _on

The reason for the activation treatment is the nickel on a very _{thermic coating} .

> .d ^ e erb.ndung ^^^^ _{isL Der so herge} .

^s ^ f "^ ^{n" n} _{iet a} very high activity.

^ eme « _{Dam frefomierung}

B _{bd actual none}

Beuh ^ _K oh, e,

There are no hydrogens that can be reformed with the aid of the catalyst according to the invention Restriction. Even a hydrocarbon with a boiling point of about 350 ° C, e.g. B. heating oil, can be very be reformed well. Even if the proportion of an unsaturated component is more than 5%, the Hydrocarbon can be used.

It is advantageous if traces of alkali metal salts, in particular alkali halide salt, are added to the aforementioned nickel catalysts, since the catalyst activity can be increased and the carbon deposition can be reduced even more. It it is believed that the alkali halide acts as a cocatalyst and the activity of nickel promotes.

Alkali hydroxide, alkali carbonate, etc. can be used as effective alkali metal salts. Chlorides, Fluorides, bromides of sodium and potassium can be used as alkali halides. It is very beneficial when the catalyst is impregnated with an aqueous solution of these compounds, wherein the amount is advantageously chosen so that a content of 1 to 8% of these compounds in the finished catalyst - calculated as a sentence - is available. There are no particulars with regard to the addition of the solution Regulations.

The cement can be shaped and hardened, followed by impregnation with these compounds takes place before the reduction by the hydrogen stream. The cement can be shaped, hardened and reduced and then impregnated with these compounds. It is also possible to use these connections or to mix the solution thereof with the cement before molding and setting.

As already mentioned, with the aid of the catalyst according to the invention, almost all hydrocarbons with a boiling point of less than 350 ^° C. can be reformed quickly and easily without carbon deposits. Such hydrocarbons are primarily natural gas, liquefied natural gas, gasoline, naphtha, naphtha-cracking residue oil, kerosene, petroleum, gas oil, etc. The reformed gas thus obtained contains carbon monoxide, carbon dioxide, hydrogen and small amounts of methane and is particularly suitable for use as town gas or as a raw material for methanol synthesis. The reformed gas can also serve as a raw material for ammonia synthesis by adding nitrogen, carbon monoxide conversion treatment, decarburization dioxide treatment, methanation, etc.

The invention is explained in more detail by means of the following examples. The hydrogen used has a degree of purity of more than 98%.

Comparative experiment 1

This test is carried out using petroleum with a specific gravity of 0.704, an initial boiling point of 55 ° C, a 50% distillation point of 84 ° C and an end point of 148 ° C, with 1.2 ppm sulfur, 17.5% naphthenic Hydrocarbons, 13.3% aromatic hydrocarbons, 0.3% olefinic hydrocarbons.

Test conditions:

Catalyst bed inlet temperature ... 500 ⁰ C.
Catalyst bed outlet temperature .. 800 ⁰ C
Reaction pressure (reactor outlet) 3 atm

Hydrocarbon, liquid, hourly

Space velocity 0.5 h ' ¹

Amount of steam supplied per

1 carbon atom of the carbon-hydrogen (mol of steam /

1 carbon atom) 2.5

Catalyst A (known from FR-PS 11 07 519)

ίο An aqueous solution containing 50 g of sodium carbonate is slowly added to the aqueous solution containing 100 g of nickel nitrate. The precipitate which formed "vird filtered and the cake thus obtained is washed and then calcined for 2 hours at 400 ⁰ C in air. The nickel oxide thus formed is mixed with alumina cement in a ratio of 1: 3 and hardened. The cured product is reduced in a hydrogen gas stream at a temperature of 600 ° C. for 10 hours.

Catalyst B

Alumina powder and alumina cement are mixed in a ratio of 1: 1. The mixture is hardened by adding an appropriate amount of water. The hardened material is calcined and cooled at a temperature of 1200 ^{° C. for 2 hours.} The cooled substance is impregnated with an aqueous solution of nickel sulfate, a nickel content of 10% (calculated as nickel oxide) being obtained. The impregnated material is calcined for 2 hours at a temperature of 400 ^° C. in air and then reduced with hydrogen gas ^{for 10 hours at 600 ° C.} This product is used for steam reforming reaction.

Catalyst C

This catalyst is obtained according to an embodiment of the invention. An aqueous solution containing 50 g of sodium carbonate is slowly added to an aqueous solution containing 100 g of nickel nitrate. The precipitate that forms is filtered off. The resulting cake is sufficiently washed and dried. The dry cake and calcium aluminate cement are completely mixed together in a ratio of 1: 1. The mixture is hardened after adding water. The cured substance is heated gas stream for 10 hours at a temperature of 600 ⁰ C in a hydrogen, at the same time reduced the nickel compound and is reduced. The catalyst obtained in this way can be used for the process according to the invention.

Catalyst D

This catalyst is also obtained and is the same according to an embodiment of the invention the catalyst B, except that it is based on potassium fluoride in an amount of 3 percent by weight the finished catalyst, is impregnated and soaked.

Catalyst E.

This catalyst is the same as Catalyst A except that it is in one with potassium fluoride Amount of 3 percent by weight (based on the finished catalyst) is impregnated and soaked.

Test results:

Catalyst A B

17.5
3.0
10.0
69.5 17.3
2.7
10.5
69.5 18.0
1.2
9.5
71.3 18.2
1.0
9.4
71.4 17.5
2.8
10.4
69.3 a lot a lot Nothing Nothing little a lot a lot Nothing Nothing little 5 3 0.0 0.0 0.3 200-
250 Ä 120-
160 A

Composition CO

(Mole percent) CH ₄

of the cracked gas CO ₂

(dry gas) H ₂

Catalyst, powdered
f carbon deposition
Pressure difference (kg / cm ² ) *)

Particle size of the nickel catalyst

*) The pressure difference was measured at the reactor inlet and outlet at the end of a test period of one hour measured.

As can be seen from the table above, Catalysts A and B are the amounts of carbon deposits and catalyst pulverization high, and a drop in pressure occurs. In the inventive Catalysts C and D shows no carbon build-up, and the methane content of the cracked one Gas is low. A comparison of the test results of the catalysts A and E shows that the Adding potassium chloride prevents carbon build-up. The experiments also show that in the decomposition of the hydrocarbon proceeds further in the case of catalyst D than in the case of catalyst C. When the size of the nickel crystals is determined by X-ray diffraction, it is found that the Catalyst obtained by reduction after oxidation of nickel (catalyst A), differs from Catalyst C produced by simultaneous decomposition and reduction will.

Comparative experiment 2

The following test results show the effect of the hydrogen concentration of the reducing Gas.

CH ₁ Gaseous Inventive CO Contaminants according to CO ₂ worked proceedings H ₂ Salary more CO ₂ than 10% composition CO 4% 2% of the reducing CH ₄ 4.5 3 Gas H, 6.5 3 Carbon deposition 85 92 composition Carbon content 19.0% 18.5% of the cracked of the catalyst 9.5 10.0 Gas 4.0 3.5 67.5 68.0 Catalyst, powdered a lot Nothing 2 wt. Nothing percent 6 wt. Nothing percent

Reduction conditions: 600 ° C, 10 Ii

example 1

An aqueous solution containing 70 g of sodium carbonate is slowly added to an aqueous solution, which contains 138 g of nickel nitrate. The resulting pulp is filtered. The resulting cake is sufficiently washed and dried. The dry cake and alumina cement are in one Ratio of 1: 3 mixed. The mixture is hardened. The hardened substance is left for 10 hours heated at a temperature of 600 ° C in a hydrogen gas stream, at the same time the nickel compound is dismantled and reduced.

Example 2

An aqueous solution containing 55 g of sodium hydroxide is slowly added to an aqueous solution containing 138 g of nickel nitrate. The resulting pulp is filtered. The resulting cake is sufficiently washed and dried. The dry cake and alumina cement are mixed in a ratio of 1: 3 and the mixture is hardened. The hardened substance is heated for 10 hours at a temperature of 600 ^° C. in a stream of hydrogen, with decomposition and reduction of the nickel compound taking place at the same time.

B e i s ρ i e i 3

A solution containing 95 g of potassium oxalate slowly becomes a solution containing 138 g of nickel nitrate added, and the precipitate that forms is filtered, washed and dried. The thus obtained dry precipitate is mixed with alumina cement in a ratio of 1: 3 and the mixture is hardened. The cured material is for 10 hours at a temperature of 600 ° C in a Hydrogen gas stream is heated, with a simultaneous decomposition and reduction of the nickel compound takes place.

Example 4

Potassium fluoride is the shaped, hardened catalyst according to Example 3 in an amount of 3% an impregnation of the catalyst with an aqueous solution of potassium fluoride and by a subsequent drying added.

Example 5

The same catalyst is prepared as in Example 1, except that the catalyst is potassium chloride impregnated with an amount of 3 percent by weight, based on the weight of the finished catalyst

Example 6

An aqueous solution containing 70 g of sodium carbonate is slowly added to an aqueous solution containing 138 g of nickel nitrate. The resulting pulp is filtered. The resulting cake is sufficiently washed and dried. The dry cake and alumina cement are mixed together in a ratio of 2: 3, and the mixture is molded and dried and hardened. The hardened substance is heated for 10 hours at a temperature of 600 ^° C. in a hydrogen gas stream, the nickel compound being decomposed and reduced at the same time.

With the catalysts prepared according to the preceding examples, steam reforming of Hydrocarbons with a low content of unsaturated hydrocarbons carried out, and it was found that there were no carbon deposits on the catalyst.

The following examples show that the catalyst which is prepared according to the invention in is equally effective with a hydrocarbon starting charge with a high content of unsaturated Hydrocarbons.

Example 7

In processes F and G, conventional nickel catalysts (GB-PS 9 53 877) are used, which can be produced as follows:

Diatomaceous earth is suspended in an aqueous solution of a nickel salt. Sodium carbonate is added to the solution. Nickel precipitates as nickel carbonate and nickel hydroxide. The precipitate is filtered and calcined in air to form nickel oxide powder. The nickel oxide is mixed with calcium aluminate cement. The mixture is molded and hardened. The reaction is carried out for 10 hours at 600 ° C. under hydrogen gas. In method F, the catalyst bed inlet temperature is set to a high value, e.g. B. 600 ⁰ C, held. In the process G, the reaction is carried out at a temperature of 400 ⁰ C.

In processes H and J, catalysts made in accordance with the invention are used. The catalyst used in process H is prepared as follows: an aqueous solution of nickel sulfate is slowly added to an aqueous solution of sodium carbonate with stirring. The precipitate that forms is filtered, washed sufficiently, and dried. The dried product is pulverized. Calcium aluminate cement is added in a ratio of 1: 1 to the powder formed in this way. The mixture is molded and hardened. The catalyst produced in this way is placed in a reaction tube and ^{heated for 10 hours at 600 °} C. in a hydrogen gas stream, the thermal decomposition and reduction of the nickel compound taking place at the same time.

The catalyst used in method J is prepared as follows: alumina powder and alumina cement are mixed well in a ratio of 1: 1. The mixture is molded and hardened by adding water. The hardened support is ^{calcined at 1200 °} C. and impregnated with a saturated aqueous solution of nickel nitrate, a nickel content of 20% being obtained. This is followed by drying. The catalyst is placed in a reaction tube and ^{heated for 10 hours at 600 °} C. under a stream of hydrogen gas, the thermal decomposition and reduction of the nickel compound taking place at the same time.

The results obtained from the comparative tests using these procedures are given below:
A 1: 1 mixture of hexane and hexene (chemical grade) is used as the batch and feedstock.

3.0 3.0 3.0 3.0 3.0 3.0

Moles of steam per 3.0
1 carbon atom
Reaction pressure (atg) 3.0
(Outlet)

Catalyst bed temperature ⁰ C

Inlet 600 400 400 400

Middle 700 550 550 550

Outlet 800 800 800 800

Composition of the cracked gas (%)

CO 16.0 15.7 15.8 15.9

CH ₄ 0.5 0.9 0.8 0.6

* ⁵ CO ₂ 12.0 12.4 12.3 12.1

H "71.5 71.0 71.1 71.4

Carbon deposition: see ¹ ) see ² ) nothing not

') At the inlet of the catalyst bed, carbon shelves was ascertained.

*) From the inlet to the middle of the catalyst bed, coals Deposition of fabric was observed.

As can be seen from the table above, when using according to the fiction Catalysts produced according to the method unsaturated hydrocarbons without carbon deposit reformed.

Claims (2)

Patent claims: 1. A method for producing a catalyst containing a nickel compound and cement, for the steam reforming of hydrocarbons, in which a mixture of the nickel compound and the cement is heated, dadur c h g e k e η η ζ e i c h η e t that the mixture which Contains 3 to 40 percent by weight of nickel, under the action of a hydrogen gas stream, which is less than 10% hydrocarbon, carbon dioxide and carbon monoxide gases at a temperature is heated from 400 to 700 ° C. 2. The method according to claim 1, characterized in that ibis 8 percent by weight alkali metal salt, preferably an alkali halide is added , "Η Tt