JPS6261641A - Preparation of monolithic methanol steam-reforming catalyst - Google Patents

Abstract

PURPOSE:To enhance the durability of a catalyst, by a method wherein a base material is immersed in an acidic aqueous solution containing a copper ion, a zinc ion, an aluminum ion and a zirconium ion and alkali is added to said solution to convert said ions to hydroxides before drying and baking the impregnated base material. CONSTITUTION:A base material such as cordierite, mullite or alumina is immersed in an aqueous solution containing Cu<++>, Zn<++>, Al<3+> and Zr<4+> as catalytically effective components and subsequently immersed in a weak alkaline aqueous solution to convert the metal ions to Cu(OH)2, Zr(OH)2, Al(OH)3 and Zr(OH)4 while the impregnated base material is dried and calcined to obtain a catalyst. Further, even if said catalytically effective components are supported, for example, by graphite to be formed into a catalyst, almost no change is confirmed in catalytic capacity.

Description

Detailed Description of the Invention (Industrial Field of Application) The present invention relates to a monolith (
This article relates to a method for producing a monolith type catalyst.

Hydrogen gas is used in the hydrogen industry as raw material for ammonia synthesis and methanol synthesis, in the oil refining industry such as hydrodesulfurization and hydrocracking,
It is used in a variety of fields including the organic chemical industry, such as the production of cyclohexane, which is a raw material for nylon, as well as the metallurgical industry and the semiconductor industry. Recently, the demand for hydrogen as a new energy source such as fuel for fuel cell power generation has been increasing.

Steam reforming from liquefied petroleum gas (IIPG), liquefied natural gas (LNG), and naphtha has been adopted as a conventionally widely used hydrogen production method, but (i) Rising prices and supply of petroleum-based raw materials unstable (ii)
Since the reaction temperature is high (800° C. to 1000° C.), there are problems such as unsuitability for small to medium scale hydrogen gas production.

In contrast, in recent years, methanol can be produced on a large scale from coal, natural gas, etc. via synthetic gas.
Furthermore, since it is easy to transport, a method of producing hydrogen gas by reacting methanol and water vapor is attracting attention. In addition, the steam reforming reaction of methanol is reformed into a gas with a high hydrogen content at a much lower temperature than naphtha.
Waste heat can be used as a heat source for this reforming reaction. Furthermore, since almost no by-products other than hydrogen and carbon dioxide are produced, it has the advantage that the separation process for obtaining pure hydrogen is simple.

(Problems to be Solved by the Invention) The methanol steam reforming reaction described above is based on the catalytic reaction of the following formula.

In the above process, methanol steam reforming is generally carried out in a fixed-bed reactor filled with a pellet-shaped catalyst, but the pressure when the reformed gas passes through the catalyst bed of the conversion reactor The problem is that the loss is large, and furthermore, the pressure loss increases over time due to the powdering of the catalyst pellets. Since the pressure loss in the conversion reactor increases the power cost required for gas transportation and also causes a decrease in the activity and durability of the catalyst, it is desired to develop a catalyst that solves the above problems.

The present invention solves the above problems and provides a monolithic methanol steam reforming catalyst.

(Means for solving the problems) The present invention provides steel ions, zinc ions, aluminum ions,
It is characterized by immersing the base material in an acidic aqueous solution containing zirconium ions, changing it into copper hydroxide, zinc hydroxide, aluminum hydroxide, and zirconium hydroxide by adding alkali, and then converting it into each oxide by drying and firing. The present invention relates to a method for producing a monolithic steam reforming catalyst.

The monolithic methanol steam reforming catalyst of the present invention has the form of a single unit and completely covers the O cross section of the reactor to be used. It corresponds to a methanol steam reforming catalyst with a honeycomb morphology providing flow channels.

Specific examples of configurations that satisfy the above conditions include those shown in FIGS. 1, 2, and 3, for example. 1st to 5th
In the figure, 5 is a base material, and 15 is a gas flow path. 11g1
~Figure 3 μ is merely an illustration of the O form of the catalyst of the present invention,
It is not limited to this.

The effective active components of the catalyst of the present invention are prepared by co-precipitating four components: steel, zinc, aluminum, and zirconium, and the content ratio of each active component is from 10 to 10% copper to 100% zinc in atomic ratio.
200, preferably 40-150, aluminum and zirconium 1-150, preferably 2-100. In addition, the catalyst is 0uO1ZnO1At, O,, Zr0
1 O exists in the form of each oxide.

The reasons for selecting the catalyst preparation method, catalyst type, and composition ratio are that co-precipitated catalysts are less likely to produce by-products such as methane than impregnated catalysts in which active metals are supported on a carrier such as alumina.

Furthermore, the four-component catalyst has excellent low-temperature activity and produces less by-products such as dimethyl ether than the two-component steel and zinc catalysts. Note that the active ingredient content ratio of the above four components is not strictly limited, but one that has appropriate methanol adsorption capacity and acidic points due to the addition of aluminum and zirconium, and has optimal activity and selectivity at the above composition ratio. It has been confirmed that (Patent application No. 60-72780J).

Notes on the catalyst preparation method are as follows.

Co-precipitation is preferably carried out by mixing a water-soluble salt of the catalyst component metal (steel, zinc, aluminum, zirconium) with an alkali metal carbonate or hydrogen carbonate or aqueous ammonia. To avoid the introduction of poisons, these salts (steel, zinc, aluminum, zirconium) Fi halides are preferably not sulfur-containing salts.

The temperature of coprecipitation is preferably 50°C to 100°C,
The pH range is preferably 5-9.

It is important that the precipitate is thoroughly washed to remove alkali metal ions and anions from the catalyst.

A specific method for preparing an effective catalytic active component is described below.

Add NaAt01 to distilled water and dissolve. Next, when concentrated nitric acid is added dropwise, At(OH)m precipitates, but is dissolved again by stirring. Furthermore, Cu(Hog)1・5H10,
Zn(NOs)m・6Hmo, Zr0(NO3)1・2
H10 is added to a predetermined composition ratio. This solution is heated to 85° C., and a 11 molar solution of Na1CO is gradually added to obtain a coprecipitate. The slurry thus obtained is stirred at 85° C. until the pH is constant at 7.0. The slurry is washed and filtered until nitrate ions are no longer detectable, dried at 110° C. overnight, and then quenched at 300° C. for 3 hours.

Please note that the active ingredients of these catalysts are based on cordierite, mullite, alumina, etc. ○um+, znl+,)
, 1m+, immersed in an aqueous solution containing Zr'10, and then
By immersing it in a weak alkaline aqueous solution, the metal ions in the base material are converted to au(OH)x, Zr(OH)1.
At(OHJs) can be used by converting it into Zr(OH)4, followed by drying and explosion.

Furthermore, it has been confirmed that even if a lubricant such as graphite is added to the active ingredients of these catalysts and the catalyst is formed into pellets, honeycombs, etc., there is almost no change in catalyst performance.

Furthermore, the amount of metal supported can be increased by increasing the strength of the base material and having appropriate acidity.
Y-type zeolite can also be included. When Y-type zeolite is contained, it is preferably 30 to 1 part by weight, preferably 20 to 5 parts by weight, per 100 parts by weight of the base material.

The present invention will now be further explained with reference to nine embodiments.

Example 1 Comparison of activity and pressure drop characteristics in the catalyst layer for a pelletized catalyst and a catalyst produced by the method of the present invention.

For pelleted catalysts, OuO-ZnO-mul@O
Graphite was added to @-Zr01 and molded into 9.5 φXILOm using a tablet molding machine. The molded nine reactors were packed into a cylindrical catalyst bed (cross-sectional area of 1&4 m, length 16 m), and two stages of this catalyst bed were loaded and a nine reactor was used to prepare the 11th reactor.
A methanol steam reforming reaction was carried out under the conditions shown below.

On the other hand, how to produce a catalyst using the method of the present invention? Go to IC9. A cordierite honeycomb base material with a cross section of 400 m x 400 cm and a length of 900 cm, which has a cross section of 1 m and 30,000 gas flow channels, is heated to 200 kli of water! ni0u
(NOs) 3H 0, Zn(NOl) 1/6H
10, NaAt01. Zr0(NOs)1 ・
2H10 respectively about 9 to 160, 9 to about 180, and about 14
9. Soak in an aqueous solution containing about 28 ml of water for 30 minutes,
Then, it was immersed in a 3M (D Na1CO1 aqueous solution for 2 hours, dried at 110°C for 12 hours, and dried at 500°C for 3 hours.
Baked for an hour. A methanol steam reforming reaction was carried out under the conditions shown in Table 1 using a reactor loaded with eight ζO catalysts in series.

The active component composition ratio of the catalyst is Cu:Zn:Musi:Zr=Cu:Zn:Musi:Zr=
The ratio is 100:70:10:10. In addition, for the activity evaluation, a mixed solution of 0HSOH/H0 = 1.5 (molar ratio) was used, which was vaporized in a preheating section and sent to the catalyst layer.

Table 1 Reaction Conditions Pressure loss in the catalyst bed at the time of catalyst loading and at time 9 after 11%,000 hours had elapsed after catalyst loading for the case where a pelletized catalyst was used and the case where a nine-catalyst manufactured by the method of the present invention was used. , methanol reaction rate, product composition 1 and 2nd
Shown in 6.

Table 2 Analysis results of methanol steam reforming reaction Similar to the pellet catalyst, the catalyst produced by the method of the present invention maintains its initial activity for a long period of time, achieving a methanol conversion rate higher than that of the pellet catalyst. This is clear from the results shown in Table 2.

Furthermore, when using a pellet catalyst, after loading the catalyst,
After 18,000 hours, the pressure loss in the catalyst layer was 510-H! The pressure drop when loading the catalyst using the method of the present invention is smaller than when using a pelletized catalyst. No increase in pressure loss was observed even after 18,000 hours had passed after loading the catalyst. Example 2 For the same base material as Example 1, cu(F+o3), 5
110, Zn(NOI)1 4H10, N
The dissolved amount of aAt01, ZrO(Now)r2ma0 was set to 1/3 of that in Example IK, and impregnation and firing were performed once, 3 times, and 10 times, and then fired, respectively, to give 0uO1ZnO based on 100 weight of the base material. , Al40g,
The total weight part of Zr01 is a2.1 & 4.2 & 8 respectively
Catalysts B and O were obtained. As a result of carrying out a methanol steam reforming reaction using these catalysts under the conditions shown in Example 1, the methanol conversion rate at the time of catalyst loading was 81 for catalyst A.
2. Catalyst B was 953s1 Catalyst ○ was 9 years old 0%, based on 100 parts by weight of the base material, 0uO1ZnO, Mu40
Even when the total weight of s s Z rO* was increased to 20 parts by weight or more, no significant change was observed in the catalyst activity, and it was confirmed that the catalyst activity remained high up to t.

Example 3 Using the same preparation method and conditions as in Example 1 except that the honeycomb base material was replaced with α-alumina, 0uO1ZnO, 140s% of aluminum was prepared.
A catalyst was obtained by supporting Zr01 on a base material.

In addition, Mu40s, which is nine active forms prepared by the coprecipitation method, has 1
This is different from the all type, which is a honeycomb base material.

As a result of carrying out a methanol steam reforming reaction using this catalyst under the reaction conditions shown in Table 1, the methanol conversion rate at the time of loading the catalyst was 9 & 8 whispers, and even after 13,000 hours, it was 953 and Example 1. It showed the same performance as the cordierite O-Nicum base material described above.

Example 4 In addition, cordierite KYM & zeolite, which is a honeycomb base material, was added at a weight ratio of 10 vt% to cordierite.
Added, wet mixed, and after death.

Two cams were molded. This base material containing Y-type zeolite was prepared using the same preparation method and conditions as in Example 1 to prepare CuO1Zn.
Catalyst E was obtained by supporting O, Mut303, and ZrO2 on a base material. The purpose of adding YW zeolite is to improve the methanol conversion activity by increasing the co-precipitation yield by easily co-precipitating active metals by improving the degree of melting of the base material.

As a result of carrying out a methanol steam reforming reaction using this catalyst under the reaction conditions shown in Table 1, the methanol conversion rate at the time of catalyst loading was 95.391, and even after 18,000 hours, q
4.8 wt%, which showed performance superior to that of the honeycomb base material made of only cordierite described in Example 1.

As detailed above, the catalyst produced by the method of the present invention solves the problem of pressure loss increasing over time in the catalyst layer that occurs when conventional pellet catalysts are used in methanol steam reforming reactions. It is effective in improving the durability of the catalyst and reducing the power cost required for gas transportation.

[Brief explanation of the drawing]

FIG. 1, FIG. 2, and FIG. 5 are diagrams explaining the shape of a monolith catalyst according to the present invention. Sub-Agents 1) Meifuku Agent Ryo Ashihara − Sub-Agent Atsuo Anzai

Claims (1)

[Claims] The base material is immersed in an acidic aqueous solution containing copper ions, zinc ions, aluminum ions, and zirconium ions, and by adding alkali, it changes into copper hydroxide, zinc hydroxide, aluminum hydroxide, and zirconium hydroxide, and then is dried and fired to form each. A method for producing a monolithic methanol steam reforming catalyst characterized by converting it into an oxide.