JPS6121733A - Catalyst for converting carbon monoxide - Google Patents

Abstract

PURPOSE:To prevent the increase in the pressure loss in a catalyst bed with the elapse of time while keeping initial activity over a long period of time, by molding a monolithic catalyst for converting carbon monoxide so as to set the thickness of a catalyst activator layer to 0.5mm. or more. CONSTITUTION:A base material consisting of a plurality of parallel plates, a plurality of cylindrical base materials or a base material having a honeycomb shape is coated or impregnated with an effective catalyst component or the effective catalyst component and a sticking component are mixed and molded to obtain a monolithic catalyst for converting carbon monoxide wherein the thickness of a catalyst activation-containing layer is set to 0.5mm. or more, pref., 0.7mm. or more. This catalyst shows activity not inferior as compared with a conventional pellet catalyst and is effective for reducing power cost required in transferring gas. Further, this catalyst is effective even in aqueous gas converting reaction for preparing hydrogen for a fuel battery or ammonia synthesis.

Description

DETAILED DESCRIPTION OF THE INVENTION (Field of Industrial Application) The present invention relates to a monolithic catalyst for a conversion reaction in which carbon monoxide is reacted with water to convert it into carbon dioxide and hydrogen.

(Conventional technology) City gas has become indispensable for today's citizen life. Coal and petroleum, which have traditionally been used as raw materials for city gas, are being replaced by liquefied petroleum gas and liquefied natural gas in large cities and their surrounding areas, but reformed petroleum gas is still the mainstream in small and medium-sized cities. is doing. Since this reformed gas contains carbon monoxide, which is toxic, there is a strong desire from various quarters to reduce the content of carbon monoxide. This reduces carbon monoxide.

In the above process, the carbon oxide conversion reaction is generally carried out in a fixed bed reactor filled with an iron oxide-chromium oxide catalyst shaped into pellets, but the reformed gas passes through the conversion reactor. The pressure loss during the process is large, and
A problem arises in that the pressure loss increases over time due to the pulverization of the catalyst pellets. Since the pressure loss in the conversion reactor causes an increase in the power cost required for gas transfer, the reformed gas production industry is desiring the development of a catalyst that solves the above problems.

In order to achieve this need, patent application No. 58-023476 describes a monolith type catalyst in which the reformed gas is brought into contact with the catalyst surface in a state where the flow direction of the reformed gas is parallel to the catalyst surface. has been done. As shown in the examples of the above-mentioned patent application, the tendency for the pressure drop in the catalyst layer to increase over time has been significantly improved compared to conventional cylindrical or pellet catalysts, but when the catalyst layer thickness is 0. It has become clear that although the monolithic catalyst of about .3-degrees shows high activity in the carbon monoxide conversion reaction at the initial stage, there is a marked tendency for the activity to decrease over time.

(Problems to be Solved by the Invention) The present invention has been made in order to eliminate the tendency for activity to decrease over time.As a result of intensive studies by the inventors regarding these activity decrease phenomena, It was found that there is a relationship between this and the thickness of the catalyst layer.

(Means to solve the problem) What is the carbon monoxide conversion monolith type catalyst of the present invention? 1.2
．． A substrate consisting of a plurality of parallel plates, a plurality of cylindrical substrates, or a substrate having a honeycomb shape, as shown in Figures 3 and 4, coated, applied or impregnated with an effective catalyst component, or the effective catalyst. The components and the viscous component are mixed, and the first
゜It is molded as shown in Figures 2.3 and 4, and the thickness of the active substance-containing layer of the catalyst is 0.5 parts or more, preferably 0.
．． 7 or more copies.

It goes without saying that the monolithic catalyst for carbon monoxide of the present invention can be applied regardless of the type of substrate and the type of active component. The following F l! is commonly used as a high temperature catalyst. 1203- Regarding Cr203-based catalyst,
The present invention will be explained with comparative examples and examples.

Comparative Example 1> Iron oxide-chromium oxide commercially available pellet catalyst (9.5m
φx a o am ) into a hollow cylindrical catalyst layer (cross-sectional area 1
&4m'', length 06m) was packed in a reactor in which two stages were loaded in series, and the pressure loss in the catalyst bed and changes in carbon monoxide conversion over time were measured under the conditions shown in Table 1.

Comparative Example 2> Dimensions in Figure 5 (21, (5+, (41 and (5)
respectively 4.5 m, 0.5 wm, 75
Fe
(NOI) 3.9H1020kg.

Or(Hog)3 ・9 HI3 2 kg, water 2
After immersing in an aqueous solution containing 0 kg for 5 minutes,
Drying was carried out at ℃ for 12 hours. After repeating the above-mentioned dipping and drying two more times, it was baked at 500° C. for 5 hours.

Using a reactor loaded with six of these catalysts in series, under the conditions shown in Table 1, the pressure loss in the catalyst layer and the change in carbon monoxide conversion over time were measured.

<Example 1> Dimensions (2), (31, (4) and (5 lights) in Fig. 5, respectively 4.5 fins, 0.9 snow, 75 m, 500
After the cordierite base material prepared as a gourd was operated and catalyzed in the same manner as in Comparative Example 2, changes in pressure loss and carbon monoxide conversion rate over time were measured under the same conditions as in Comparative Example 2.

<Example 2> Fe(OH)3, 0r(OH)s, and microcrystalline cellulose powder known as a forming aid were mixed at 80% and 10%, respectively.
%.

After uniformly mixing at a weight ratio of 10%, the shape is the same as that in Figure 5 and the dimensions (2), (3), (4) and (5) are shown in the figure.
) are respectively 4.5 tm + 0.7 wm and 7
5 yes, molded to 500 m and fired at 300°C for 3 hours. Using this catalyst, pressure loss and changes in carbon monoxide conversion over time were measured under the same conditions as in Comparative Example 2.

<Example 3> Dimensions (2), (sl, (4) and (5) in Fig. 5
) of 45 m, 0.5 m, and 75 m, respectively.
, 500 wa and the base material were operated and catalyzed in the same manner as in Comparative Example 2, and then changes in pressure loss and carbon monoxide conversion rate over time were measured under the same conditions as in Comparative Example 2.

<Example 4> A slurry prepared by pre-mixing 375 parts of Fe(OH), 10 parts of 0r(OH%), 15 parts of silica sol, and 50 parts of water was ground overnight in a ball mill, and the catalyst catalyzed in Example 1 was mixed into this slurry. After removing the excess slurry, the cordierite was dried and fired at 300°C for 3 hours.The thickness of this catalyst layer was measured using an electron microscope, and a new 125 catalyst layer was observed on the cordierite. Using this catalyst, pressure loss and changes in carbon monoxide conversion over time were measured under the same conditions as in Comparative Example 2.

<Example 5> A slurry was prepared in the same manner as in Example 4, the cordierite base material used in Example 2 was immersed in the slurry, excess slurry was removed, and then dried 1. After repeating this operation twice, it was fired at 300° C. for 3 hours. When the thickness of this catalyst layer was measured using an electron microscope, it was found that the thickness of the catalyst layer was 0.
．． A five-pharyngeal catalyst layer was observed. Using this catalyst, pressure loss and changes in carbon monoxide conversion over time were measured under the same conditions as in Comparative Example 2.

Table 1 Reaction conditions Note that the raw material gas composition is as shown in Table 2.

Table 2 Raw material gas composition (vo1%, dry 'base) Figure 6 shows the change in pressure loss over time in the catalyst layer for Comparative Examples 1 and 2 and Examples 1, 2, 3, and 4°5. Figure 7 shows the change in conversion rate over time. As shown in the results shown in Figure 6, when the pelletized catalyst of Comparative Example 1 was used, the pressure loss began to increase after 4000 hours had passed after loading the catalyst, and when 10,000 hours had passed, the pressure loss started to increase.
85 tm H2O is reached. On the other hand, when the monolithic catalysts of Comparative Example 2 and Examples 1.2, 5, and 4.5 were used, the pressure loss during catalyst loading was lower than when using pellet catalysts. 10.000 after loading
No increase in pressure loss was observed even after the passage of time.

- As shown in Figure 7, the catalyst layer thickness of Comparative Example 2 was α3
With the snow monolith catalyst, a decrease in carbon monoxide conversion rate was observed after 4000 hours had passed. On the other hand, the catalysts of Examples 1, 2, 3, and 4.5 maintained their initial activity for a long period of time, similar to the pellet catalyst of Comparative Example 1, and even after 10,000 hours had passed after loading the catalyst, The carbon monoxide conversion rate is comparable to that at the initial stage.

As detailed above, the catalyst of the present invention exhibits comparable activity in carbon monoxide conversion reactions compared to conventional pellet catalysts, and the pressure loss in the catalyst layer is reduced when conventional pellet catalysts are used. This solves the problem of increase over time and is effective in reducing the power cost required for transporting reeds and gas. The catalyst produced by the method of the present invention is an effective catalyst in water gas conversion reactions such as hydrogen production for fuel cells and hydrogen production for ammonia synthesis, and is not limited to use in city gas production.

[Brief explanation of the drawing]

FIG. 1 is an explanatory diagram of an example of the shape of a plate-shaped catalyst, FIG. 2 is an explanatory diagram of an example of the shape of a cylindrical catalyst, FIGS. 3 and 4 are explanatory diagrams of an example of the shape of a honeycomb-shaped catalyst, Figure 5 is a diagram specifically showing the shape of the honeycomb-shaped catalyst described in Comparative Examples and Examples, and Figure 6 is a diagram showing the pressure loss over time in the catalyst bed of a conversion reactor loaded with the catalysts of Comparative Examples and Examples. Figure 7 is a diagram showing changes over time in the carbon monoxide conversion rates of catalysts of comparative examples and examples. (1) in Figures 1 to 4 indicates the gas flow direction, and (1) in Figure 5 2
) is the pitch (sum of one hole and wall thickness), (3) is the wall thickness, (
4) and (5) indicate external dimensions. Sub-Agent 1) Meifu Agent Ryo Hagiwara - Figure 5

Claims (1)

[Claims] A monolithic catalyst for carbon monoxide conversion, characterized in that the thickness of the active layer is 0.5 mm or more.