JPH05245379A - Cyclic gasification catalyst and production thereof - Google Patents

Abstract

PURPOSE:To provide a cyclic gasification catalyst excellent in heat resistance, thermal shock resistance and durability, small in depositing quantity of carbon, economical and maintaining high activity. CONSTITUTION:This catalyst is obtained by depositing one or two or more kind of nickel oxide, cobalt oxide and a metal of platinum group on a catalytic carrier containing mainly aluminum oxide Al2O3 and a metal oxide expressed by MeO. The main component of the catalyst consists of about 25-40mol MeO per 100mol aluminum oxide, and Me is two or three kind of metals selected from group consisting of Ca, Ba and Sr.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a catalyst for gasifying hydrocarbons in a cyclic gasifier for producing city gas and a method for producing the same.

[0002]

2. Description of the Related Art The methods of gasification by hydrocarbon reforming used for city gas production are roughly classified into a cyclic method and a continuous method according to their operating methods. As a hydrocarbon reforming catalyst, a catalyst carrier based on alumina, silica, magnesia or the like on which Ni and / or Co as a catalytically active component is carried is widely used. Platinum group noble metals such as Rh and Ru are also used as active ingredients, but these have high activity but have a price drawback, and so far have not been used as widely as Ni and Co. Even in the city gas industry, the cyclic method,
Regardless of the continuous method, the situation is similar.

As the carrier used for the steam reforming catalyst, oxides of Mg, Ca, Sr, Ba, Al, Ce, Si, Ti, Zr and the like, or a combination of two kinds of these oxides are known. But
From the standpoint of mechanical strength, heat resistance, chemical stability, etc., alumina-based carriers are most often used today. It is also known to add an alkaline earth metal oxide to the alumina carrier for the reforming catalyst to improve its properties. For example, JP-B-44-17337 discloses that Mg, Ca, Sr or Ba is contained in a catalyst.
A reforming catalyst containing 10 to 20 wt% of is disclosed, and it is claimed that carbon deposition during the reaction is small. Further, in JP-A-63-141643, 100 mol of aluminum oxide and a metal oxide represented by MeO (Me is Ca, Ba, Sr) 3-25
V, Cr, Fe, Co, Ni, Cu, on a carrier containing a molar ratio of
A catalyst comprising at least one selected from the group consisting of Mo, Ag, Cd, La, Ce, perovskite and a platinum group noble metal is disclosed, and the catalyst mainly relates to a catalyst for catalytic combustion.

As a steam reforming catalyst for hydrocarbons, aluminum oxide 100 is disclosed in JP-A-2-75344.
It contains a metal oxide represented by MeO (Me is Ca, Ba, Sr) in an amount of 3 to 25 mol, and these components are mainly contained.
A composite oxide represented by MeO.6Al ₂ O ₃ in which Ni, Co and / or a platinum group precious metal is supported on a catalyst carrier existing in the carrier is disclosed, and a molding aid such as calcium alumina cement is disclosed. Has been shown to be effective in producing excellent reforming catalyst supports.

[0005]

Industrially, nickel-based catalysts are used as gasification catalysts for city gas production.
As the carrier, a refractory material such as alumina, silica or magnesia is usually used. However, those catalysts are not always satisfactory in terms of heat resistance, thermal shock resistance, durability, etc., and (1) a large amount of carbon is deposited which causes a decrease in activity and strength. 2) A catalytically active component such as Ni or Co reacts with a carrier component such as alumina to form nickel aluminate Ni Al ₂ O ₄ or cobalt aluminate Co Al ₂ O ₄
Is generated to reduce the activity, and the like.

As a result of pursuing a steam reforming catalyst which solves these problems, the present inventors have developed the catalyst described in the above-mentioned Japanese Patent Laid-Open No. 2-75344, which causes less carbon precipitation, a catalyst component and a carrier component. We have proposed an excellent reforming catalyst with little activity deterioration due to the reaction of, but even with this catalyst, it is difficult to completely prevent activity deterioration and strength reduction in the case of cyclic gasification. It turns out that improvement is desirable.

[0007]

According to the present invention, a nickel oxide, a cobalt oxide and a platinum group noble metal among a nickel oxide, a cobalt oxide and a platinum group noble metal are formed on a catalyst carrier containing aluminum oxide Al ₂ O ₃ and a metal oxide represented by MeO as main carrier components. 1 or 2 or more of the above, wherein the main component of the catalyst support contains MeO in an amount of about 25 to 40 mol per 100 mol of aluminum oxide.
Is a cyclic gasification catalyst characterized by being two or three metals selected from the group consisting of Ca, Ba and Sr.

The catalyst preferably carries 1 to 50 parts by weight of nickel oxide and / or cobalt oxide, and 0.01 to 3 parts by weight of at least one platinum group noble metal, per 100 parts by weight of the catalyst carrier. Preferably.

The present inventors have further found that aluminum oxide and / or hydroxide (Al ₂ O ₃ and / or Al ₂ O ₃ .nH
₂ O) and the Me compound and the necessary amount of molding aid such as calcium / alumina cement as Al ₂ O ₃ : MeO molar ratio.
After mixing in a ratio of 100: (25-40), if necessary, this is shaped and then calcined to obtain a catalyst carrier, and the catalyst carrier contains at least one of nickel compound, cobalt compound and platinum group noble metal compound. It has been found that the catalyst of the present invention can be obtained by impregnating an aqueous solution containing ## STR3 ## and then heating this.

The method for producing the catalyst of the present invention is not limited to the above-mentioned production method, of course, and it is a method commonly used or known in the catalyst industry as a method for producing a catalyst, for example, JP-A-2-75344. All the methods described can be used.

The catalyst carrier according to the present invention is about 25-40 mol, preferably about 25-35 mol, per 100 mol of aluminum oxide.
It is desirable to include MeO in a molar ratio. If the proportion of MeO is less than 25 moles, the main components such as NiAl ₂ O ₄ will not sufficiently prevent activity deterioration and develop strength, and if it contains more than about 40 moles of MeO, heat resistance or thermal shock resistance will increase. It is easy to lose the sex.

In the present invention, Me represents at least two kinds of Ca, Sr and Ba in the alkaline earth metal of Group IIa, and Mg in the alkaline earth metal has a sufficiently satisfactory catalytic property. Is not obtained, and a combination of Ca, Sr, and Ba is particularly effective. Of course, addition of a small amount of Mg to these components is not excluded. Out of the combination of Me
The combination of Sr-Ca, Ba-Ca, and Sr-Ba-Ca is the most preferable choice in the technical and economical sense because commercially available calcium alumina cement can be used as a molding aid.

The catalyst carrier according to the present invention contains a large amount of MeO.6Al ₂ O ₃ crystals having excellent heat resistance as a main component. Furthermore, by X-ray analysis, MeO · nAl ₂ O ₃ (n is a number such as 1, 2)
The presence of α-Al ₂ O ₃ crystals has been confirmed, and it is considered that this contributes to the strength of the catalyst carrier, the reaction suppressing ability of NiAl ₂ O _4, etc., the durability, etc. It is desirable to minimize the presence of ₂ O ₃ .

In the present invention, the content of Ni and / or Co is preferably in the range of 1 to 50% by weight, particularly 1 to 25% by weight as NiO and CoO with respect to the catalyst carrier. Catalyst component Ni
If the amount of Co and / or Co is too large or too small, the activity of the steam reforming reaction becomes low. If the amount of the catalyst component is too large, the excellent properties of the carrier may not be utilized for the catalyst performance.

The platinum group noble metal may be used alone or in combination with Ni and / or Co, and the supported amount is preferably in the range of about 0.01 to 3% by weight based on the carrier. About 0.01
If it is less than about 3% by weight, the activity is not sufficient, and if it exceeds about 3% by weight, it is not economically advantageous.

The catalyst of the present invention may be used in the form of powder, but it is usually used as a molded product such as a tablet, a ring, a sphere, or an extrusion molded product. The catalyst or catalyst carrier of the present invention may be molded without using a molding aid, but in this case the molding operation is rather difficult, and it is preferable to mold using a suitable molding aid. As the molding aid, all binders generally used in the catalyst industry such as methyl cellulose, organic binders such as polyvinyl alcohol, inorganic binders such as cements can be used, but use of calcium alumina cement or the like is particularly desirable. In this case, a remarkable improvement in activity is expected as a secondary effect. The addition amount of the molding aid varies depending on the type of the molding aid used, but in the case of calcium alumina cement, it is preferably about 10 to 40% by weight based on the main component of the carrier.

The catalyst of the present invention is used for a steam reforming reaction in city gas production by cyclic gasification. As feedstock, methane, ethane, propane, butane and mixtures thereof, LPG, naphtha, kerosene, crude oil,
Petroleum hydrocarbons such as heavy oil are used.

[0018]

EXAMPLES Next, the present invention will be described in more detail with reference to examples, but it goes without saying that the present invention is not limited to these examples.

[Example 1] Strontium hydroxide, aluminum hydroxide and calcium alumina cement were mixed with Sr.
O; CaO: Al ₂ O ₃ were mixed so that the molar ratio was 10: 17: 100, and then mixed by a wet method for 30 minutes. The calcium alumina cement used was Al ₂ O ₃ about 80.5 wt% and CaO about 19.5%.
It contained wt%. After drying this mixture at 400 ° C for 4 hours,
With a press machine, outer diameter 1.9 cm x height 1.9 cm x inner diameter 0.7 cm (3 /
It was molded into a ring shape of 4 inches × 3/4 inches × 9/32 inches), aged overnight, dried at 400 ° C., and then calcined at 1300 ° C. for 5 hours to obtain a catalyst carrier. The crush strength of this carrier is 75
X-ray diffraction measurement showed that the composition of this carrier was Sr.
O ・ 6Al ₂ O ₃ , CaO ・ 6Al ₂ O ₃ , CaO ・ 2Al ₂ O ₃ and α-Al ₂
It was a mixed crystal of O ₃ . This carrier was impregnated with an aqueous solution of nickel nitrate and further calcined at 600 ° C. for 5 hours to obtain a catalyst of the present invention. The amount of nickel supported on this catalyst was 5% by weight as nickel oxide.

[Comparative Example 1] SrO: CaO: Al ₂ O ₃ molar ratio
Other than changing the blending amount of the raw materials to be 13: 9: 100,
A catalyst of Comparative Example 1 was obtained in the same manner as in Example 1. The crush strength of the carrier after firing was 40 kg. Since this catalyst has much lower strength than the catalyst of Example 1, no steaming test was conducted.

Comparative Example 2 A catalyst of Comparative Example 2 was obtained in the same manner as in Example 1 except that magnesium nitrate was used instead of strontium hydroxide. The composition of the catalyst carrier is MgO: CaO
The molar ratio of Al ₂ O ₃ was 19: 14: 100.

[Comparative Example 3] A catalyst in which nickel was supported on a mullite carrier which is currently used industrially was used as a catalyst of Comparative Example 3.

The physical properties of the catalysts of Example 1 and Comparative Examples 1, 2 and 3 are shown in Table 1 below.

[0024]

[Table 1]

[Example 1 of use] A steaming test was conducted using the catalysts of Example 1 and Comparative Example 2, and the test results as shown in the following Table 2 were obtained.

[0026]

[Table 2]

The steaming test is a method for investigating the effect of steam on the catalytic activity, and the test catalyst is tested for 15 hours.
It is held in a steam atmosphere (steaming), the catalyst before and after steaming is immersed in hydrochloric acid, and the difference in the amount of nickel to be eluted is measured. The decrease in the amount of elution depends on the formation of nickel aluminate NiAl ₂ O ₄ , which decreases the catalytic activity. Therefore, the larger the decrease is, the greater the decrease in activity is.

USE EXAMPLE 2 (Activity Test Under Normal Conditions) The catalysts obtained in Example 1, Comparative Example 2 and Comparative Example 3 were tested for activity under normal conditions as follows.

[Table 3] Raw material: LPG with over 98% butane LHSV: 1.6 hr ^-1 Steam ratio: 1.21 (However, the steam amount during the purge period and the heat period is 1 during the make period)
6.9%) Reaction temperature: 1023K Reaction pressure: Normal pressure Cycle time: 240 s / cycle Hot standby atmosphere: Air atmosphere (1023K)

[0029]

[Table 4]

As can be seen from Table 4, the catalyst obtained in Example 1 is more active than the catalysts obtained in Comparative Examples 2 and 3 because it has a larger amount of gas production and a higher butane decomposition rate. Is. It is also clear that the amount of carbon deposited on the catalyst is small because the carbon balance is large.

[Example 3 of use] (Durability test under normal conditions) A durability test of 203 hours was performed under the conditions of Example 2 of use. The results are shown in Figure 1. This exam 43
No change with time was observed in the production amount, gasification efficiency, butane decomposition rate, carbon balance, and calorific value of generated gas, even if continued for a day.

[Use Example 4] (Durability Test under Acceleration Conditions) Since the atmosphere of hot standby differs between the conditions of Use Example 2 and the actual device, Example 1, Comparative Example 2, and Comparison were performed under the following conditions. The accelerated durability test of the catalyst obtained in Example 3 was performed.

[Table 5] Raw material: LPG with over 98% butane LHSV: 1.6 hr ^-1 Steam ratio: 1.21 (However, the steam amount in the purge period and the heat period is the same amount as the make period) Reaction temperature: 1023K Reaction pressure: Normal pressure Cycle time : 240 s / cycle Hot standby atmosphere: Steam atmosphere (1073
K) The results are shown in Table 6 below and FIG. In FIG. 2, ◯ indicates the catalyst obtained in Example 1, ● indicates the catalyst obtained in Comparative Example 2, and Δ indicates Comparative Example 3.
The catalysts obtained in step 1 are shown below.

[0033]

[Table 6] Under steaming conditions, the activity of the catalyst obtained in Comparative Example 2 is significantly reduced, and the catalyst obtained in Example 1 maintains high activity even under these conditions.

[0034]

As described above, according to the present invention, it is possible to obtain a cyclic gasification catalyst which is heat resistant, heat shock resistant, durable and economical and maintains high activity.

[Brief description of drawings]

FIG. 1 is a characteristic diagram showing the change over time in the amount of gas produced as a result of a durability test of the catalyst obtained in Example 1 under normal conditions.

[Fig. 2] Fig. 2 is a characteristic diagram showing the change over time in the amount of gas produced by the test results of the catalysts obtained in Examples and Comparative Examples 2 and 3 under accelerated conditions.

 ─────────────────────────────────────────────────── (72) Inventor Yasuo Nishioka 3-5-6 Hikoshimasako-cho, Shimonoseki City, Yamaguchi Prefecture (72) Inventor Toshio Matsuhisa 4-8-23 Hikoshimasako-cho, Shimonoseki City, Yamaguchi Prefecture

Claims (9)

[Claims] 1. A nickel oxide, a cobalt oxide, and a platinum group noble metal on a catalyst carrier containing aluminum oxide Al ₂ O ₃ and a metal oxide represented by MeO as a main carrier component.
One or two or more supported catalysts, the main component of which is MeO in an amount of about 25 to 40 mol per 100 mol of aluminum oxide, and Me is composed of calcium Ca, barium Ba and strontium Sr. 2 or 3 selected from the group
A cyclic gasification catalyst characterized by being a kind of metal. 2. The catalyst according to claim 1, wherein about 1 to 50 parts by weight of nickel oxide and / or cobalt oxide is supported on 100 parts by weight of the catalyst carrier. 3. The catalyst according to claim 1, wherein about 0.01 to 3 parts by weight of at least one platinum group noble metal is supported on 100 parts by weight of the catalyst carrier. 4. A catalyst carrier carrying 100 parts by weight of nickel oxide and / or cobalt oxide in an amount of about 1 to 50 parts by weight, and one or more platinum group metals in an amount of about 0.01 to 3 parts by weight. A catalyst according to claim 1 which comprises: 5. Aluminum oxide and a metal oxide represented by Me, which form the main component of the carrier, are mainly MeO.6Al ₂
The catalyst according to claim 1, 2 or 3 which is present in the catalyst as a complex oxide represented by O ₃ . 6. Besides MeO · nAl the catalyst carrier support composed mainly _{MeO · 6Al 2 O 3 2 O} 3 (n is an integer of 1 or more) and alpha-Al ₂ O ₃ according to claim 1 which contains , 3, 4, or 5 catalyst. 7. An oxide and / or hydroxide of aluminum and a Me compound (Me is Ca, Ba or Sr of 2 or 3).
And a molding aid are mixed in a molar ratio of Al ₂ O ₃ ; MeO of 100: (25 to 40) and then calcined to form a catalyst carrier. A method for producing a cyclic gasification catalyst, which comprises impregnating an aqueous solution containing at least one of a cobalt compound and a platinum group noble metal compound, and then heating this. 8. The molding is carried out with or without the addition of a molding aid to the mixture of the aluminum oxide and / or hydroxide and the Me compound prior to calcination of the catalyst carrier.
The method described. 9. The method according to claim 8, wherein the molding aid is calcium alumina cement.