JP2914206B2 - Nickel-supported catalyst for hydrocarbon reforming and method for producing the same - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

The present invention relates to a nickel-supported catalyst for hydrocarbon reforming and a method for producing the same. More specifically, the present invention relates to a nickel catalyst supported on a silicon and / or aluminum-containing carrier for a hydrocarbon reforming reaction using carbon dioxide, steam or oxygen as an oxidizing agent, and a method for producing the same.

A nickel-supported catalyst is industrially very important as a catalyst widely used for a reduction reaction such as a reforming reaction, a hydrogenation reaction and a methanation reaction because of the high activity of nickel metal. Nickel-supported catalysts are used in particular in the production of the main starting material of C1 chemistry in the chemical industry as catalysts in steam reforming processes for natural gas, oil, naphtha and the like. These catalysts are also used for producing synthesis gas, which is a raw material for producing methanol, ammonia, oxygen-containing compounds, and the like.

[0003]

2. Description of the Related Art As a method for producing a nickel-supported catalyst,
Various methods such as a coprecipitation method, an impregnation method, an ion exchange method, a precipitation-sedimentation method, a sol-gel method, and an aerogel method have been proposed so far, and the production method differs depending on the type and form of the carrier. The method of producing and treating the nickel catalyst greatly changes the characteristics of the catalyst.

[0004] For example, German Patent Publication No. 2,255,9
No. 09 discloses Ni ₆ Al ₂ which is a catalyst precursor by a coprecipitation method.
(OH) ₁₆ CO ₃ .4H ₂ O is produced and calcined to produce N 2
It discloses that an i-Al-based catalyst is produced and used as a catalyst for a naphtha steam reforming reaction. In another German Patent Publication No. 2,024,282, 15.3% of _{Ni (NO 3) 2 6H 2} O and 7.6% of _{Al (NO 3) 2 9H 2} O and Na in an aqueous solution containing ₂ CO
₃ is added and coprecipitated to produce a nickel-supported catalyst that is a steam reforming catalyst for methane. Japanese Patent Publication No. 57-156,303 proposed a method of supporting a nickel metal component on a natural zeolite by an impregnation method. That is, a natural zeolite was added to a 1 molar aqueous solution of Ni (NO ₃ ) ₂ , impregnated at 100 ° C. for 1 hour, and then calcined at 400 ° C. for 1 hour. Then, when applied to a steam reforming reaction of natural gas, higher activity was obtained as compared with a general nickel catalyst supported on aluminum.

[0005]

As described above, generally used nickel-supported catalysts are mostly produced by a wet method. Such a wet production method not only requires a drying step, but also has a problem in industrial implementation since acidic and basic wastewater is generated by the production method.

An object of the present invention is to provide a nickel-supported catalyst which does not require a drying process, has no waste water problem, and is a highly active catalyst for methane reforming reaction instead of an industrially expensive noble metal-supported catalyst. It is in. The object of the present invention is also
Nickel or nickel and alkali metals and / or alkaline earths, which have a high activity on hydrocarbon reforming reactions using oxidizing agents such as carbon dioxide, steam and oxygen and can be produced conveniently and economically There is also to provide a metal supported catalyst.

[0007]

SUMMARY OF THE INVENTION An object of the present invention is to provide a low melting point nickel salt having a temperature of 100 ° C. or lower and, if necessary, an alkali metal salt and / or an alkaline earth metal salt, by using zeolite and silica. Surface area of 10 selected from gamma-alumina, silicate and silica-alumina
Physical mixing with a carrier of 0 m ² / g or more at room temperature, heating to a certain temperature above the melting point of the salts to decompose metal salts while melting all the salts, and 300
This is achieved by a method for producing a nickel-supported catalyst, comprising a step of calcining at a temperature in the range of to 1200 ° C.

[0008] The method of mixing the metal salt and the carrier is preferably uniformly ground using a mortar or a ball mill and mixed.

In melting the salt, it is preferable that the salt is melted in a firing furnace at a temperature higher than the melting point of the metal salt, particularly in the range of 100 ° C. to 400 ° C.

The calcination is preferably carried out in an oxygen or gas stream containing oxygen at a calcination temperature of 300 ° C. to 1200 ° C.

When zeolite is used as a carrier,
Preference is given to those having a pentasil type structure, wherein the content of aluminum to silicon in the structure is in the range of 0 to 1.0 in terms of molar ratio.

The alkali metal salt of the catalyst is, for example, a potassium, sodium or cesium salt.

The alkaline earth metal salt is, for example, a calcium, magnesium, strontium or barium salt.

The metal salt has a low melting point of 500 ° C. or less;
Preference is given to nitrates, chlorides, acetates, carbonates of alkali metals, alkaline earth metals and nickel.

The nickel content of the catalyst is particularly preferably 1 to 20% by weight, the alkali metal content is particularly preferably 10% by weight or less, and the alkaline earth metal content is particularly preferably 20% by weight or less.

Hereinafter, the present invention will be described in detail with reference to examples, but these do not limit the scope of the present invention.

[0017]

【Example】

Example 1 Nickel nitrate (melting point: 56.7 ° C.), calcium nitrate (melting point: 39.7 ° C.) and potassium nitrate (melting point: 370 ° C.) were converted to potassium: nickel: calcium = 0.08: 1.0: A crystalline zeolite I having a high surface area pentasil-type ZSM-5 structure, compounded at a molar ratio of 3.2 (silicon / aluminum molar ratio> 500)
And physically mixed well. The temperature was raised from room temperature to 400 ° C. at a rate of 2 ° C. per minute under an argon stream to melt all the nitrates, and then heated to 400 ° C. for 4 hours under an oxygen stream to decompose the nitrates. And heated again for 4 hours to produce a calcium-nickel-calcium / zeolite I (melted) catalyst supported on zeolite I. The results obtained by measuring the specific surface area of the produced catalyst by nitrogen adsorption at a liquid nitrogen temperature by the BET method,
It was 180 m ² / g.

In order to measure the activity of the produced catalyst, it was applied to a methane reforming reaction using carbon dioxide as a model reaction. That is, the potassium-nickel-calcium / zeolite I catalyst produced by the above-mentioned melting method was filled in a 1/4 inch quartz reactor, pretreated with hydrogen, and then subjected to normal pressure, 700 ° C., space velocity 60,000 / hr. Under the conditions described above, the partial pressure of carbon dioxide is 0.25 atm.
The reaction was carried out with the methane molar ratio fixed at 1: 1. The conversion rates of carbon dioxide and methane and the yields of carbon monoxide and hydrogen measured under these reaction conditions are as described in Table 1.

Comparative Example In this comparative example, a catalyst having the same components and composition as in Example 1 was produced by an impregnation method.
A nitrate of the same metal as in Example 1 was dissolved in water with the same composition to form an aqueous solution, and this aqueous solution was added with crystalline zeolite I of the same weight, stirred with a stirrer, and then used with an electric heater. The solution was dried by evaporating water at 120 ° C., heated to 650 ° C. in an electric furnace, and heat-treated for 4 hours. The specific surface area of the produced catalyst was 181 m ² / g as measured by the same method as in Example 1 above. The catalytic activity was compared as in Example 1 using the calcium-nickel-calcium / zeolite I (impregnated) catalyst prepared by the impregnation method as the catalyst under the same model reaction and the same conditions as in Example 1 above. The results of the reaction are as described in Table 1 below.

Example 2 The present example relates to the results obtained by applying the catalyst produced by the method of Example 1 to a methane reforming reaction using carbon dioxide and measuring the catalyst stability depending on the reaction time. It is. The catalyst activity was measured at a reaction temperature of 800 ° C., and other conditions were the same as in Example 1.
The activity according to the reaction time is shown in Table 2 below. The conversion of carbon dioxide is 93%, which is close to the thermodynamic equilibrium value, and the catalyst activity is maintained almost constant despite the reaction at a high temperature of 800 ° C. for 140 hours or more. Was done. After the reaction, as a result of measuring the weight of the catalyst, there was no weight increase due to coke formation, and as a result of observing the shape of the catalyst after the reaction with an electron microscope, no coke was formed.
The shape was almost the same as before the reaction.

Example 3 Nickel nitrate was used as a nickel precursor, magnesium nitrate (melting point: 89 ° C.) was used as a magnesium precursor, and the same crystal as that used in Example 1 was used as a carrier. Zeolite I
In the same manner as in Example 1 above, the nickel content was the same as in Example 1, and nickel-magnesium / zeolite I (molar ratio of nickel to magnesium: 1: 2.2) was used. A (melted) catalyst was prepared. The catalyst activity was measured under the same reaction conditions as in Example 1 above, and the results are shown in Table 1.

Example 4 Nickel nitrate was used as a nickel precursor, and the same crystalline zeolite I used in Example 1 was used as a carrier, and nickel was used in the same manner as in Example 1 above. A nickel / zeolite I (molten) catalyst having the same content as in Example 1 was produced.
The catalyst activity was measured under the same reaction conditions as in Example 1 above, and the results are shown in Table 1.

Example 5 The above-mentioned Example was carried out using nickel nitrate as a nickel precursor and crystalline zeolite II having a pentasil-type ZSM-5 structure (silicon / aluminum molar ratio = 50) as a carrier. In the same manner as in Example 1, a nickel / zeolite II (melted) catalyst having the same nickel content as in Example 1 was produced. The catalyst activity was measured under the same reaction conditions as in Example 1 above, and the results are shown in Table 1.

Example 6 Nickel nitrate was used as a nickel precursor and pentasil type ZSM-5 was used as a carrier.
Using crystalline zeolite III having a structure (silicon / aluminum molar ratio = 30), nickel / zeolite III (nickel content is the same as in Example 1) in the same manner as in Example 1 above. A (melted) catalyst was prepared.
The catalyst activity was measured under the same reaction conditions as in Example 1 above, and the results are shown in Table 1.

[Example 7] Using nickel nitrate as a nickel precursor and silica as a carrier, the nickel content was also adjusted in the same manner as in Example 1 above.
A nickel / silica (fused) catalyst identical to was prepared. The catalyst activity was measured under the same reaction conditions as in Example 1 above, and the results are shown in Table 1.

Example 8 Nickel nitrate was used as a nickel precursor, and gamma-alumina was used as a carrier. The nickel content was the same as in Example 1 using the same method as in Example 1. A nickel / gamma-alumina (molten) catalyst was produced. The catalyst activity was measured under the same reaction conditions as in Example 1 above, and the results are shown in Table 1.

Example 9 From the same catalyst as used in Example 1 above, under the same reaction conditions, but using methane and carbon dioxide as the reactants and steam /
The reaction activity when methane was added at a ratio of 1/10 was investigated. As a result, the conversion rates of methane and carbon dioxide were 76% and 79%, respectively, and the yields of carbon monoxide and hydrogen were 74% and 82%, respectively. Compared with Example 1, the conversion of carbon dioxide and the yield of hydrogen increased by 1% and 3%, respectively, while the conversion of methane and the yield of carbon monoxide decreased by 3%, respectively. . The synthesis gas ratio (ratio of hydrogen / carbon monoxide) was 1.11, which was 12% higher than that in Example 1 above.

Example 10 From the same catalyst as used in Example 1 above, under the same reaction conditions, except that methane and carbon dioxide were used as the reactants and oxygen / methane ratio 1 / When 10 was added, the reaction activity was investigated. The results showed that the conversions of methane and carbon dioxide were 80% and 66%, respectively, and the yields of carbon monoxide and hydrogen were 74% and 80%, respectively. Example 1 above
Compared to, the conversion of methane and the yield of hydrogen increased by 1% and 2%, respectively, while the conversion of carbon dioxide and the yield of carbon monoxide decreased by 13% and 5%, respectively. The synthesis gas ratio (ratio of hydrogen / carbon monoxide) is 1.08
And increased by 9% as compared with Example 1 described above.

As shown in Table 1, at normal pressure and at a reaction temperature of 70
A comparison of the catalytic activity for the methane reforming reaction using carbon dioxide at 0 ° C. and a space velocity of 60,000 / Hr shows that potassium-nickel-calcium in which nickel, potassium, and calcium are supported on a zeolite I carrier by a melting method. In the case of the / Zeolite I (melted) catalyst, an improvement in conversion and yield of about 20% or more was observed as compared with the potassium-nickel-calcium / Zeolite I (impregnated) catalyst produced by the impregnation method. Also, various nickel-supported catalysts produced by a melting method without the addition of a cocatalyst can obtain high methane and carbon dioxide conversions of 70 to 80% close to the thermodynamic equilibrium value and hydrogen and carbon monoxide yields. Was done. As shown in FIG. 1, for the potassium-nickel-calcium / zeolite I (molten) catalyst,
Even when the reaction was carried out at a high reaction temperature of 800 ° C. for 140 hours or more, a result was obtained in which high activity was maintained without reducing coke generation and catalytic activity.

Table 1 Conversion (%) Yield (%) Category Catalyst Dioxide Methane Hydrogen monoxide Carbon Carbon Example 1 Potassium-nickel-calcium 79 78 79 78 / Zeolite I (melted) Comparative Example 1 Potassium- Nickel-Calcium 58 59 59 59 / Zeolite I (impregnated) Example 3 Nickel-Magnesium 69 83 75 76 / Zeolite I (melted) Example 4 Nickel / Zeolite I (melted) 78 78 77 77 Example 5 Nickel / Zeolite II (Fused) 77 79 78 78 Example 6 Nickel / zeolite III (fused) 68 72 70 71 Example 7 Nickel / silica (fused) 75 77 76 76 Example 8 Nickel / gamma-alumina (fused) 78 78 72 78
Note) The yield of carbon monoxide is shown as a percentage (%) of the partial pressure of carbon monoxide generated by the reaction with respect to the sum of the partial pressures of carbon dioxide and methane charged before the reaction. It is shown as a percentage (%) of the hydrogen partial pressure generated with respect to twice the methane partial pressure before the reaction.

[0031]

The potassium-nickel-calcium / pentasil-type zeolite catalyst produced by the melting method of the present invention is a nickel / pentasil-type zeolite catalyst produced by the melting method and the impregnation method, and the potassium produced by the impregnation method. The higher activity compared to the nickel-calcium / pentasil type zeolite catalysts is due to the increased interaction between potassium, nickel and calcium and the interaction of the metal component with silicon in the support due to the melting process; It is presumed that the alkali metal and alkaline earth metal promoters used as promoters increase the affinity of carbon dioxide.

[Brief description of the drawings]

FIG. 1 is a graph showing the relationship between the reaction time and the conversion of carbon dioxide when the catalyst of Example 10 is used in the reaction, which is data of the present invention.

Claims (11)

(57) [Claims] 1. The method according to claim 1, wherein the nickel salt having a low melting point of 100 ° C. or less and the alkali metal salt and / or the alkaline earth metal salt are selected from zeolite, silica, gamma-alumina, silicate and silica-alumina.
Physically mixing at room temperature with a carrier of at least 00 m ² / g,
Heating to a certain temperature above the melting point of the salts to decompose the metal salts while melting all the salts;
A method for producing a nickel-supported catalyst for a hydrocarbon reforming reaction using carbon dioxide, water vapor, oxygen or the like as an oxidizing agent, comprising a step of firing at a temperature range of 0 to 1200 ° C. 2. The method for producing a nickel-supported catalyst according to claim 1, wherein the mixing of the metal salt and the carrier is performed by uniformly grinding using a mortar or a ball mill. 3. The method for producing a nickel-supported catalyst according to claim 1, wherein the step of melting and decomposing the metal salt is carried out at a temperature higher than the melting point of the metal salt, particularly in the range of 100 ° C. to 400 ° C. . 4. The nickel-supported catalyst according to claim 1, wherein the zeolite support has a pentasil-type structure, and the content of aluminum to silicon in the structure is 0 to 1.0 in a molar ratio. Manufacturing method. 5. The catalyst according to claim 1, wherein the alkali metal component of the catalyst is potassium,
The method for producing a nickel-supported catalyst according to claim 1, wherein the catalyst is sodium or cesium. 6. The method for producing a nickel-supported catalyst according to claim 1, wherein the alkaline earth metal salt of the catalyst is calcium, magnesium, strontium or barium. 7. The method according to claim 1, wherein the metal salt is selected from nitrates, chlorides, acetates and carbonates of alkali metals, alkaline earth metals and nickel having a low melting point of 500 ° C. or lower. Item 4. A method for producing a nickel-supported catalyst according to Item 1. 8. The catalyst has a nickel content of 1 to 20% by weight.
The method for producing a nickel-supported catalyst according to claim 1, wherein: 9. The method according to claim 1, wherein the alkali metal content of the catalyst is 0 to 10% by weight. 10. An alkaline earth metal content of the catalyst of 0 to 10.
The method for producing a nickel-supported catalyst according to claim 1, wherein the amount is 20% by weight. 11. A low melting point nickel salt of less than 100 ° C. and, if necessary, an alkali metal salt and / or an alkaline earth metal salt, selected from zeolite, silica, gamma-alumina, silicate and silica-alumina, having a surface area of 100 m 2. ² / g or more of the carrier is physically mixed at room temperature, and the mixture is heated to a certain temperature above the melting point of the above salts to decompose the metal salts while melting all the salts, and then at 300 to 1200 ° C. Manufactured by firing in the temperature range of
Nickel-supported catalyst for hydrocarbon reforming reactions using carbon dioxide, steam, oxygen, etc. as oxidants.