JPS63248444A - Steam reforming and/or partial oxidation catalyst for hydrocarbon - Google Patents

Abstract

PURPOSE:To improve the activity and the stability of the activity of the title catalyst by depositing a Pt group metal on an inorganic carrier calcined after depositing Ni, Co, etc., forming thus a catalyst contg. metallic Ni or Co generated by the reduction of a part of the deposited Ni, Co during the use of the catalyst. CONSTITUTION:Ni and/or Co are(is) deposited on an inorganic carrier comprising alumina, magnesia, silica, or an inorg. material consisting primarily of each thereof, or a mixture thereof, and at least a major part of the deposited Ni and/or Co is calcined, providing thus a calcined product together with the inorganic carrier. Then, a Pt group metal is also deposited providing thus a steam reforming catalyst for hydrocarbon, wherein at least a part of the calcined product is reduced in the stage of usage to metallic Ni and/or Co. Preferred content of Ni or Co is 1-50wt.% per unit weight of the catalyst.

Description

Detailed Description of the Invention (Industrial Application Field) The present invention relates to a catalyst for steam reforming and/or partial oxidation of hydrocarbons, and more specifically, a catalyst for steam reforming and/or partial oxidation of hydrocarbons. Various fuel gases such as city gas, gas for fuel cells, methanol synthesis, oxo synthesis,
It is useful as a raw material gas for various synthesis such as ammonia synthesis, gas for reduced iron production, gas for high purity hydrogen production, etc.
The present invention relates to a catalyst suitable for producing a mixed gas containing hydrogen, methane, carbon oxide and/or carbon dioxide as main components.

(Prior art) Conventionally, hydrogen, methane, - As a catalyst for obtaining a mixed gas mainly composed of carbon oxide and/or carbon dioxide, transition metals such as nickel, cobalt, ruthenium, and rhodium as active components are used to oxidize inorganic materials such as alumina, magnesia, and silica. A product in which the material is held on a carrier has been proposed and put into practical use.

(Problems to be solved by the invention) Conventionally, this type of catalyst has (i) high activity;
(ii) The activity is stable over a long period of time, that is, the activity is excellent in sustainability; (iii) The reaction continues for a long period of time without carbon precipitation even under conditions of low steam/hydrocarbon ratio. However, at present, conventional catalysts are not sufficient to satisfy these requirements.

However, factors that inhibit the stability of this type of catalyst, that is, the sustainability of its activity, include poisoning by sulfur compounds in the raw hydrocarbon, precipitation of carbon, sintering of metals as active components, and nickel or cobalt. Nickel spinel CoA/l when using a catalyst formed by supporting on an alumina support at a high temperature of about 700°C or higher 20. Similarly, formation of a solid solution of nickel or cobalt and magnesia when a catalyst supported on a magnesia-based carrier is used, and similarly formation of nickel silicate or silicic acid when a catalyst supported on a silica-based support is used. Examples include the production of cobalt. The formation of spinel, solid solution, or silicate described above makes reduction by hydrogen or the like difficult, resulting in a decrease in the number of catalytic active sites. The above-mentioned carbon precipitation as a factor that inhibits the stability of the catalyst, that is, the sustainability of its activity, occurs when the reaction is carried out under conditions of a low steam/hydrocarbon ratio, when the catalyst has a low ability to resist carbon precipitation, and when the raw material This is generated on the catalyst surface when hydrocarbons become heavy, but in order to improve the carbon deposition ability of the catalyst, conventional methods such as adding potassium and using basic carriers have been carried out. However, it is not in a satisfactory condition.

(Means for Solving the Problems) The present inventors steam-reform and/or partially oxidize hydrocarbons to obtain a mixed gas containing hydrogen, methane, carbon oxide, and/or carbon dioxide as main components. The catalyst has high activity, excellent activity stability, that is, durability, and high carbon precipitation resistance, and does not cause carbon precipitation even under low steam/hydrocarbon ratio conditions. With the aim of obtaining a catalyst that can continue the reaction for a long period of time, as a result of intensive research, nickel and/or cobalt was supported on an inorganic support such as alumina, magnesia, or silica, and the support was carried out by firing. Nickel and/or cobalt together with an inorganic carrier are used as a calcined product consisting of spinel, solid solution or silicate, which are conventionally regarded as factors that inhibit the stability of catalyst activity, and then a platinum group metal is supported. Unlike the conventional catalysts mentioned above, it is easily reduced to metallic nickel or cobalt by hydrogen-containing gas, etc., so it is believed that the catalyst obtained by reducing it with hydrogen-containing gas, etc. will be able to achieve the above purpose. This discovery led to the completion of the present invention.

That is, the present invention supports nickel and/or cobalt on an inorganic carrier made of alumina, magnesia, silica, or an inorganic substance containing each as a main component, or a mixture thereof, and then bakes the supported nickel and cobalt. At least a large part of the cobalt is formed into a calcined product together with the inorganic carrier, and then a platinum group metal is supported, and upon use, at least a part of the calcined product is reduced to form nickel and/or metal in the metallic state. The present invention provides a catalyst for steam reforming and/or partial oxidation of hydrocarbons, characterized in that the catalyst is cobalt or cobalt.

The feature of the present invention is that nickel and/or cobalt is
A fired product, in which at least a large part of the nickel and/or cobalt supported on an inorganic carrier such as alumina, magnesia, or silica and fired together with the inorganic carrier;
That is, nickel spinel NiAβ204 and/or cobalt spinel Co formed with an alumina support
Aj2. O, After forming a solid solution of magnesia support and nickel and/or cobalt, or nickel silicate and/or cobalt silicate formed together with a silica support, the platinum group metal supported is further reduced with hydrogen-containing gas, etc. Another object of the present invention is to provide a catalyst in which at least a part of the calcined product is used as nickel and/or cobalt in a metallic state.

Hydrocarbons to be steam reformed and/or partially oxidized in the presence of the catalyst of the present invention include those mainly composed of lower hydrocarbons such as natural gas to those mainly composed of higher hydrocarbons such as naphtha. Included.

Alumina used as an inorganic carrier in the present invention,
Forms of magnesia and silica that have only undergone a low-temperature history tend to form the calcined product at lower temperatures, facilitate subsequent reduction, and have better catalytic performance. . For example, γ- or η-alumina provides a catalyst with better performance than α-alumina.

Examples of inorganic substances containing alumina as a main component used in the present invention include zeolite, amorphous silica/alumina,
Examples include activated clay.

Examples of the inorganic substance containing magnesia as a main component used in the present invention include magnesite, fired products thereof, and dolomite.

Examples of inorganic substances containing silica as a main component used in the present invention include kaolin, diatomaceous earth, zeolite, amorphous silica/alumina, and activated clay.

In the present invention, nickel and/or cobalt,
The method of supporting the inorganic carrier is not particularly limited as long as it is supported uniformly, and conventionally known methods such as impregnation method,
A precipitation method, a mixing method, etc. can be applied.

In the present invention, the amount of nickel and/or cobalt supported on the inorganic carrier is 1 to 50% by weight, preferably 5 to 301% by weight of metal based on the weight of the catalyst used.
It is. If the content is less than 1% by weight, the catalyst performance will deteriorate, which is undesirable, and if it exceeds 50 heavy-duty cylinders, it is unfavorable from the economic point of view.

In the present invention, the fired product obtained by firing is
Nickel spinel formed with alumina support
A 1.0. and/or cobalt spinel CoAf
204, a solid solution of magnesia-based carrier and nickel and/or cobalt, or nickel silicate and/or cobalt silicate formed together with a silica-based carrier, 7
Formation becomes noticeable from about 00°C, but the difficulty of its formation depends on the firing temperature, the form of the inorganic carrier, the state of supporting the metal as the active ingredient, etc. Upon calcination, the majority of the supported nickel and/or cobalt is removed, typically 50%.
As mentioned above, preferably 80% or more should be the calcined product, thereby improving the catalyst performance, that is, the activity, the sustainability of the activity, etc. The nickel and/or cobalt supported on the inorganic carrier is, for example,
700°C to 1500°C in air, preferably 800°C to 1
It is baked at a temperature of 200°C for about 1 hour or more. When the above-mentioned firing temperature is less than 700°C, the production of the fired product is not sufficient, and when it exceeds 1500°C, the surface area decreases and reduction to nickel and/or cobalt becomes difficult, which is not preferable.

After firing, a platinum group metal, preferably platinum, ruthenium, palladium or rhodium, is then supported by a known method such as a dipping method. The amount of platinum group metal supported is from 0.01 to 10% by weight in metallic form, based on the weight of the catalyst used;
Preferably it is 0.02 to 1%. The above content is 0
．． If it is less than 0.01% by weight, the catalyst performance deteriorates, which is undesirable, and if it exceeds 10% by weight, it is not preferred from the economic point of view.

Next, after the platinum group metal is supported, it is reduced in an atmosphere of hydrogen-containing gas, raw material hydrocarbon gas, etc. at a temperature of 500°C or more, preferably 600°C to 800°C for about 1 hour or more, and the fired product is reduced. at least 1 part, preferably 20-1
It is used as a catalyst in a state where 00% is nickel and/or cobalt in the metallic state. Alumina-based carriers and silica-based carriers are more easily reduced than magnesia-based carriers. That is, in the case of alumina-based carriers and silica-based carriers, good catalytic performance is achieved when the reduction rate to metallic nickel and/or cobalt is close to 100%, whereas in the case of magnesia-based carriers, Even if the reduction rate is low (50% or less, a catalyst with extremely high activity and stability can be obtained.If the reduction temperature is less than 500°C, the reduction does not substantially proceed, If the reduction temperature is too high, the activity of the resulting catalyst decreases, the activity decreases significantly over time, and deterioration accelerates, which is undesirable.

In the steam reforming and/or partial oxidation reaction of hydrocarbons carried out in the presence of the catalyst of the present invention, a raw material hydrocarbon and one or more of steam, oxygen, air, carbon dioxide, etc. are mixed in a reactor filled with a catalyst. by introducing a known method, for example, reaction pressure from normal pressure to several 10 kg/cffl·G, reaction temperature from 350 to
The process is carried out at about 1000° C., and a mixed gas containing hydrogen, methane, carbon oxide and/or carbon dioxide as main components is obtained. As the reactor, an adiabatic or external heating type, a continuous type or a cyclic type can be advantageously used.

(Effects of the Invention) According to the present invention, since the platinum group metal is supported, the reduction of the fired product is facilitated, and the activity and stability of the activity, that is, the sustainability, are significantly improved. A catalyst for steam reforming and/or partial oxidation of hydrocarbons is provided.

According to the present invention, steam reforming of hydrocarbons and/or hydrocarbons having a high carbon precipitation resistance ability and capable of continuing the reaction for a long period of time without carbon precipitation even under low steam/hydrocarbon ratio conditions An oxidation catalyst is provided.

According to the present invention, therefore, there is substantially no carbon precipitation, and the minimum steam/hydrocarbon ratio that allows the reaction to continue for a long period of time is significantly lowered, making it possible to reduce operating costs and increasing catalyst activity. Due to its high activity and long-lasting activity, manufacturing equipment costs can be significantly reduced.

(Example) The present invention will be specifically explained with reference to Examples and Comparative Examples.

Example 1 γ-alumina powder was molded into pellets using a tablet machine and
Preliminary firing was performed at 0°C for 3 hours, then immersed in an aqueous solution of nickel nitrate, and after drying, a portion was heated at 800°C and 10°C, respectively.
It was fired in air at 00°C and 1200°C for 3 hours. The conversion rates to nickel spinel after firing were 80%, 100%, and 100%, respectively. Then,
After cooling to room temperature, it was immersed in an aqueous solution of ruthenium nitrate at a specified concentration and dried at 120° C. to obtain three types of catalysts A, B, and C, each having a different firing temperature.

The ruthenium content in the three types of catalysts thus obtained was all 0.1% by weight, and the nickel content was all 20% by weight.
% by weight. A catalyst was similarly prepared using cobalt in place of nickel in Catalyst B, and Catalyst E was similarly prepared using a mixed solution of approximately equal amounts of nickel nitrate and cobalt nitrate.

These five types of catalysts were pulverized into 10 to 16 meshes, and 0.8 g of each was diluted with quartz beads and filled into a reaction tube with an inner diameter of 10 fl to a length of 20 meshes. Each of these reaction tubes was placed in an electric furnace, and hydrogen was flowed for 2 hours under conditions of normal pressure and 750° C. to reduce the catalyst. Next, 100 cc/hr of desulfurized liquid butane and pure water such that H, O/C = 2 (1 mol) were vaporized and mixed and supplied to the reaction tube under normal pressure. The reaction was carried out while adjusting the output of the electric furnace so that the temperature of the catalyst layer was 600°C, and the composition of the produced mixed gas was measured 30 minutes after the start of the reaction, the C8 conversion rate at that time was determined, and then 24 hours after the start of the reaction. 01 after the start of the reaction with a conversion rate of 30
The amount of decrease relative to that in minutes was calculated. The obtained results are the first
Shown in the table. The 01 conversion rate here means the conversion rate of butane into C8 components of methane, carbon oxide, and carbon dioxide, and is expressed by the following formula, and serves as an index of catalyst activity.

The reduction rate of the calcined product to metallic state nickel and/or cobalt was about 30% for catalyst C;
Almost 100% for all catalysts A, B, D, and
Met.

Example 2 A test similar to Example 1 was conducted on catalyst A by introducing butane and pure water after vaporization and mixing without reduction with hydrogen, and the C0 conversion rate was 1 immediately after the start of the reaction.
Although it was as low as 0%, it gradually increased thereafter and reached a steady value of about 70% 3 hours after the start of the reaction.

Example 3 Commercially available magnesia, silica gel, and commercially available magnesia to which 10% by weight of alumina cement was added were used as inorganic carriers, respectively, and pre-calcined in the same manner as in Example 1, immersed in an aqueous solution of nickel nitrate, and °C,
It was fired at 1000°C and 800°C. The conversion rate to the calcined product was approximately 100% in all cases. Catalysts F, G and H were then obtained in the same manner as in Example 1. The ruthenium content in each of the obtained catalysts was 0.05% by weight, and the nickel content was 20% by weight in each case.

Next, the catalyst was reduced for 2 hours, and then the same catalyst performance test as in Example 1 was conducted. The results are shown in Table 1. As is clear from the results shown in Table 1, the catalyst using a magnesia-based carrier in particular showed excellent performance, and
The initial activity after 1 minute is high, and the activity decreases little over time.

On the other hand, the reduction rate to metallic nickel was 100% for catalyst G, and 41% and 49% for catalysts F and H, respectively.

Example 4 Catalyst 1 in which 0.05% by weight of each of platinum, palladium and rhodium was supported in place of ruthenium in catalyst F. J and K were prepared and catalytic performance tests were conducted in the same manner as in Example 1. The results obtained are shown in Table 1.

As is clear from the results shown in Table 1, the initial activity of Catalyst J 30 minutes after the start of the reaction is somewhat inferior to that of Catalysts I and K, but all catalysts show a small decrease in activity over time and are excellent. This shows the persistence of the activity.

Comparative Example 1 A catalyst was prepared in the same manner as Catalyst A in Example 1, except that the firing temperature after immersion in nickel was 500°C. The reduction rate to metallic nickel was 100%. Table 1 shows the results of the catalyst performance test conducted in the same manner as in Example 1.

Comparative Example 2 Catalyst M was prepared in the same manner as Catalyst A in Example 1, except that ruthenium was not supported after calcination at 1000°C. The reduction rate to metallic nickel was 84%. Example 1
Table 1 shows the results of a catalyst performance test conducted in the same manner as above.

Comparative Example 3 The T-alumina pre-fired in Example 1 was
After pulverizing into 16 meshes, the catalyst was immersed in an aqueous ruthenium nitrate solution to prepare a catalyst N in which 0.3% of ruthenium was supported as ruthenium. Reduction to metallic state ruthenium is 50
It was carried out at 0°C. Table 1 shows the results of the catalyst performance test conducted in the same manner as in Example 1.

Example 5 Catalyst O was prepared in the same manner as Catalyst B, except that the pellets in Catalyst B were molded into a Raschig ring having an outer diameter of 16 mm, an inner diameter of 611 mm, and a height of 16 m. Catalyst 0 was placed in a reaction tube with an inner diameter of 751 m, and the height was 2.5 m.
j2 was filled. An electric furnace was installed around this reaction tube, and the reaction tube was heated so that the outer wall temperature of the reaction tube was around 850° C. during the reaction. The reduction of catalyst 0 is carried out in a mixed stream of hydrogen and nitrogen,
The test was carried out at a catalyst layer temperature of 690 to 770° C. under normal pressure for 3 hours.

After completion of the reduction, desulfurized liquid naphtha 131/Hr with a final boiling point of 120°C is heated and vaporized and mixed with steam in an amount such that HzO/C = 3 (1 mol), and the pressure is 3 kg/c.
d-G into the reaction tube. The reaction temperature was 400° C. at the inlet of the catalyst layer and 710° C. at the outlet of the catalyst layer.

As a catalyst performance test, when the reactant was steam, the temperature distribution of the catalyst layer was measured 100 hours after the start of the reaction. The results are shown in FIG. As is clear from the results in FIG. 1, in the case of catalyst O, the temperature rise near the entrance of the catalyst layer was gradual, meaning that the endothermic reaction was sufficiently progressing and the catalyst activity was high.

In addition, the 01 conversion rate and the approach temperature at the outlet of the catalyst layer 3 hours after the start of the reaction were measured at a position 100 meters from the inlet of the catalyst layer. The results obtained are shown in Table 2. The initial activity 3 hours after the start of the reaction was high, and the decrease in activity over time, that is, the deterioration, was extremely small.

Example 6 The supply amount of liquid naphtha is 9°I! /Hr, the amount of water vapor supplied was reduced to H2O, /C = 2 (1 mol), carbon dioxide gas was supplied 9 Nm3/Hr instead, the temperature of the outer wall of the reaction tube was changed, and the catalyst A catalyst performance test was carried out in the same manner as in Example 5, except that the temperature at the inlet of the layer was 450°C and the temperature at the outlet of the catalyst layer was approximately 750°C.

The results obtained are shown in Table 2.

As is clear from the results in Table 2, the initial activity 3 hours after the start of the reaction was high in this case as well, and the decrease in activity over time, that is, deterioration, was extremely small.

Example 7 4.5Nm of air instead of carbon dioxide! A catalyst performance test was conducted in the same manner as in Example 6, except that /Hr was supplied. The results obtained are shown in Table 2. As is clear from the results in Table 2, the initial activity 3 hours after the start of the reaction was high, and the decrease in activity over time was small.

Example 8 Platinum was used instead of ruthenium in Catalyst H, and instead of pellets, it was molded into a Raschig ring shape with an outer diameter of 16 mm, an inner diameter of 6 mm, and a height of 161 mm.
t-prepared. 1.21 of this catalyst P with an inner diameter of 100 m
of the diameter of the reactor. The height of the catalyst layer at that time was about 150 nm. After a subsequent reduction in the presence of hydrogen at 700°C for 5 hours, the reactor was charged with 1.2 Nm"/i(r) of preheated butane and 14.4 Nm"/i(r of air) under atmospheric pressure.
Nn+3/llr was supplied. The reaction was carried out while controlling the temperature at the outlet of the catalyst layer to about 700°C. - Butane conversion was 100%. The composition of the produced mixed gas 3 hours after the start of the reaction was as follows.

H2COCo□ CH4Nz 22.2 19.0 3.3 0.7 54.8
(Volume %) Furthermore, the decrease in catalyst activity over time was also extremely small.

Comparative Example 4 Catalyst Q was prepared in the same manner as in Example 5 after molding into the same Raschig ring shape as in Example 5 instead of pellets in the catalyst, and a catalyst performance test was conducted under the same conditions as in Example 5. The results obtained are shown in Table 2. In both cases, the catalyst activity decreased significantly over time, and the operation had to be stopped after a short period of time. Carbon deposition on the catalyst also increased. The temperature distribution of the catalyst layer was measured in the same manner as in Example 5. The results obtained are shown in FIG. In Figure 1, the faster the temperature rise near the inlet of the catalyst layer, the smaller the heat absorption due to the reaction and the lower the catalytic activity.
It can be seen that this is significantly lower than that of .

Comparative Example 5 A catalyst performance test was conducted in the same manner as in Example 6 except that catalyst Q was used. The results obtained are shown in Table 2. As is clear from the results in Table 2, the activity of Catalyst Q significantly decreased over time, indicating that the deterioration was significant.

From the descriptions in the above Examples and Comparative Examples, it is clear that when the catalyst of the present invention is used for steam reforming and/or partial oxidation reactions of hydrocarbons, it has a higher activity and a longer duration of activity than conventional catalysts. In other words, it can be seen that it has excellent durability.

[Brief explanation of drawings]

FIG. 1 is a graph showing the temperature distribution within the catalyst layer 100 hours after the start of the reaction for catalyst O of the present invention and catalyst Q for comparison.

Claims (1)

[Claims] 1. Nickel and/or cobalt is supported on an inorganic carrier made of alumina, magnesia, silica, or an inorganic substance containing each as a main component, or a mixture thereof, and is supported by firing. At least a large part of nickel and/or cobalt is formed into a sintered product together with the inorganic carrier, and then a platinum group metal is supported, and when used, at least a part of the sintered product is reduced to form nickel in a metallic state. A catalyst for steam reforming and/or partial oxidation of hydrocarbons, characterized in that the catalyst contains cobalt and/or cobalt. 2. Nickel and/or cobalt in an amount of 1 to 50% by weight as metal based on the weight of the catalyst used,
The catalyst according to claim 1, which is supported on an inorganic carrier. 3. The catalyst according to claim 1, wherein the nickel and/or cobalt supported on the inorganic carrier is calcined at a temperature of 700°C to 1500°C. 4.50 of supported nickel and/or cobalt
% to 100% form a calcined product with an inorganic support. 5.80 of supported nickel and/or cobalt
5. The catalyst according to claim 4, wherein % to 100% of the calcined product is formed together with the inorganic carrier. 6. Claim 1, wherein the fired product is nickel spinel NiAl_2O_4 or cobalt spinel CoAl_2O_4 formed together with alumina; a solid solution of magnesia and nickel or cobalt; or nickel silicate or cobalt silicate formed together with silica. Catalysts as described. 7. The catalyst according to claim 1, wherein the platinum group metal is platinum, ruthenium, palladium or rhodium. 8. The catalyst according to claim 1, wherein the platinum group metal is supported in an amount of 0.01 to 10% by weight based on the weight of the catalyst used.