JPH02107332A - Partition type catalyst and reactor using said catalyst - Google Patents

Abstract

PURPOSE:To enhance reaction efficiency and simplify the subject apparatus by preparing a platelike catalyst by cutting a hydrogen-occluding alloy ingot resulting from the structural growth of a La-Ni-Ni eutectic alloy with a directional solidification in a specific direction into a predetermined size. CONSTITUTION:A hydrogen-occluding alloy ingot resulting from the structural growth of a La-Ni5-Ni eutectic alloy with a directional solidification is cut at right angles to the growth direction into the platelike catalysts of a predetermined size. Specifically, there is obtained a partition type catalyst wherein LaNi5 (1) and Ni (2) under structure growth with a directional solidification are present in a eutectic form. In a reactor using this partition type catalyst, a disc-shaped partition type catalyst 3 is disposed between copper gaskets 4 in such manner as to divide this reactor into a hydrogen supply chamber A and a reaction chamber B. The reaction chamber B is provided with a conduit pipe 6 for feeding material and with a conduit pipe 7 for discharging the same.

Description

Detailed Description of the Invention [Industrial Application Field] The present invention relates to a partition type catalyst made of a hydrogen storage alloy in which an aligned structure is grown by unidirectional solidification of a LaNi5-Ni eutectic alloy, and a reaction device for the catalyst. .

[Prior Art] Today, in the chemical industry, there are many reactions that use catalysts.Catalysts are used to efficiently cause reactions in each process, and when selecting a catalyst, it is important to select a catalyst in a small amount. It is important to generate as many target products as possible within a unit of time. That is, catalysts are required to have high activity and excellent reaction selectivity.

On the industrial side, on the other hand, a wave of remarkable technological innovations is approaching from coal chemistry to petrochemistry, and research into catalyst development has been significantly affected, and new processes based on the development of new catalysts are being actively developed. In this trend, the development of catalysts with higher activity and superior reaction selectivity than conventional ones is needed, for example, for hydrogenation of carbon monoxide contained in coal liquefaction reactions, hydrogenolysis of alkyl aromatic compounds, benzene, cyclohexane, etc. It can dramatically advance processes in various reactions such as the hydrogenation of naphthalene, and its social utility is extremely large.

As mentioned above, the performance required for a catalyst includes high catalytic activity, excellent reaction selectivity, and long life. Looking at the catalysts currently in use by element, in addition to those belonging to Group 8 of the periodic table, there is Cu, and more broadly, there are also oxides and sulfides of metals of Groups 6 and 7 of the periodic table, as well as complex compounds. be.

All of these are used as metals, but in practice they are used to increase activity by giving a large surface area to a small amount of catalyst.
It is necessary to improve heat resistance by preventing sintering.

Therefore, it is extremely rare to use it as a metal wire or metal plate, and in most cases activated carbon, alumina (A
1. Powder surfaces such as O, ), diatoms ± (Sift) or their molded bodies are usually called carriers, and 5-ring φX5m+
A chemical method (deposition method, impregnation method, coprecipitation method, etc.) is applied to the inner and outer surfaces of
0 to 100 angstrom metal fine particles (support material) such as Mo or CO are attached or deposited (called a supported catalyst or supported catalyst, and the catalyst surface area is approximately 200 m
'/y) is used as a catalyst. With this catalyst,
Hydrogen adsorbed on the support material (retained hydrogen) contributes to the hydrogenation reaction of gaseous or liquid unsaturated hydrocarbons.

[Problems to be solved by the invention] However, the catalyst using the above-mentioned catalyst carrier has the following problems: ■ The catalyst carrier is destroyed during the reaction process, and the supported material of 10 to 100 angstroms is destroyed. They float or scatter, and it is impossible to separate them from the reaction products; ■Due to internal diffusion, only the carriers on the surface of the aggregate act on the reaction, and the carriers inside are not effectively utilized. , Therefore, the reaction requires an excess of catalyst: ■ Because the catalyst shape is fine-grained, the reaction is necessarily a method in which the charging material (unreacted material) passes through the catalyst packed bed; In order to increase the productivity of the catalyst, a large amount of energy is required to transport the charged raw materials (unreacted materials), and it is also difficult to control a uniform reaction (causing pressure loss and flow disturbance); ■Since the particles are packed in a packed bed, it is difficult to control the heat that enters and exits during the reaction, and side reactions occur as a result. In addition, high temperatures may deactivate the catalyst.

On the other hand, in recent years, catalysts using hydrogen storage alloys have been actively developed. Hydrogen storage alloys absorb a large amount of hydrogen when they react with hydrogen at low temperatures, and since this absorbed hydrogen is in the form of atoms, high reactivity can be expected if this absorbed hydrogen can be used for hydrogenation reactions.

If a catalyst material that utilizes the function of the hydrogen storage alloy that exhibits high activity in hydrogenation reactions of organic or inorganic compounds could be developed, the fields of its application would be vast.

Therefore, the object of the present invention is to provide a completely new type of hydrogen permeable partition type catalyst using a hydrogen storage alloy and a reaction apparatus for using the catalyst.
The purpose is to solve the problems of the conventional metal catalysts mentioned above.

[Means for Solving the Problems] The present invention provides that the LaNi5-Ni eutectic alloy has pulverization resistance and a function of absorbing hydrogen in the form of atoms, and that the eutectic phase interface is aligned in one direction. This was completed based on a series of research results showing that hydrogen diffusivity was significantly improved.

That is, the present invention is a plate-shaped hydrogen storage alloy ingot made of a LaNi5-Ni eutectic alloy grown with an aligned structure through unidirectional solidification, cut into predetermined dimensions at right angles to the growth direction of the structure. The present invention relates to a special wall type catalyst characterized by the following.

Furthermore, the present invention provides a hydrogen supply chamber equipped with a hydrogen supply conduit, a reaction chamber equipped with a feedstock flow conduit and a product flow conduit,
and a reaction device for a partition type catalyst, which comprises a partition type catalyst which partitions the hydrogen supply chamber and the reaction chamber and is installed such that one of the cross sections of the catalyst is in contact with the hydrogen supply chamber and the other side is in contact with the reaction chamber. The present invention relates to a reaction device for a partition wall type catalyst, characterized in that it is a partition wall type catalyst.

[Function] The problems with the conventional metal catalysts mentioned above are: ■ It is necessary to develop a barrier-wall type catalyst made of a hydrogen-permeable hydrogen storage alloy instead of a fine-grained one; ■ Furthermore, its cross section must be coated with other metal elements. or furthermore,
This problem can be solved by making a catalyst with dramatically higher activity and selectivity by using a cocatalyst effect of dispersing and applying an alkali metal or alkaline earth metal onto the coating (surface decoration).

The material used in the catalyst of the present invention is a hydrogen storage alloy obtained by growing an aligned structure of a LaNi5-Ni eutectic alloy by unidirectional solidification. This hydrogen storage alloy is disclosed in Japanese Patent Application Publication No. 60-135538.
It is stated in the No. This hydrogen storage alloy eliminates the drawbacks of conventional hydrogen storage alloys, such as being brittle and becoming pulverized due to volumetric expansion and contraction that accompanies hydrogen absorption and desorption. This is what I did.

The barrier wall type catalyst of the present invention is a hydrogen storage alloy ingot made by unidirectionally solidifying the above-mentioned LaNi5-Ni eutectic alloy to grow an aligned structure. It is a plate-shaped object cut to the dimensions of .

FIG. 1 is a schematic cross-sectional view of the partition wall type catalyst of the present invention. As is clear from FIG. 1, in the catalyst of the present invention, LaN15(1) and N1(2), which have grown in an aligned structure by unidirectional solidification, exist in a eutectic system. Although FIG. 1 shows a catalyst having a circular cross-sectional shape, it should be understood that the cross-sectional shape is not limited to this.

The partition type catalyst of the present invention is obtained by cutting the above-mentioned hydrogen storage alloy, which has grown an aligned structure by unidirectional solidification, in a direction perpendicular to the growth direction of the structure.
The thickness is about 2 to IC1+-. If the thickness of the catalyst is less than 2 mm, it is undesirable because the installation may sometimes break due to lack of mechanical strength, and if it exceeds 10 MII, it is undesirable because the hydrogen permeation amount will be significantly reduced. .

The partition type catalyst obtained as described above can be subjected to various reactions using the reaction apparatus schematically shown in FIG. To explain the reaction apparatus shown in FIG. 2, the reaction apparatus has a disk-shaped partition type catalyst (3) with a copper gasket (3) separating the hydrogen supply chamber (A) and the reaction chamber (B).
4). In addition, the hydrogen supply chamber (A) must be installed so that the above-mentioned cut surface of the partition type catalyst is in contact with the hydrogen supply chamber (A) and the reaction chamber (B), respectively.
Hydrogen is supplied to the hydrogen supply chamber (A) through the conduit (5). Next, hydrogen is diffused from the hydrogen supply chamber (A) to the reaction chamber side via the hydrogen supply chamber side of the partition type catalyst. In this case, hydrogen can be supplied by pressurized supply or by electrochemical supply.

The reaction chamber (B) is also equipped with a conduit (6) for the feed stream (for example unsaturated hydrocarbons+hydrogen) and a conduit (7) for the product stream (for example saturated hydrocarbon).

Using the atomic hydrogen diffused into the reaction chamber through the partition-type catalyst of the present invention, the hydrogenation reaction (e.g., ethylene (conversion reaction to ethane).

Here, the reaction conditions for the hydrogenation reaction of unsaturated hydrocarbons vary depending on the type of unsaturated hydrocarbon used, but
For example, in the case of the hydrogenation reaction of ethylene to ethane, 0 to
The temperature is 50°C. Here, the temperature can be controlled by means such as submerging the entire reactor in a water bath, and the hydrogen in the hydrogen supply chamber (A) is 0.1 to 0.5 MPa.
It is preferable to maintain the pressure at a pressure of (absolute pressure), and although it varies depending on the type of raw material (raw material hydrocarbon) charged in the reaction chamber (B), for example, in the case of ethylene, the partial pressure is maintained at 0.1 to
It is preferable to maintain the partial pressure of hydrogen at 0.3 to 0.7 to 0.9, and the mixed gas of ethylene and hydrogen is preferably maintained at 0.1
It is preferable to maintain the pressure at MPa<absolute pressure. Note that the pressure of each component can be controlled by a compressor.

By conducting the reaction using the above-mentioned reactor, the following advantages can be obtained; ■ Good separation of the product and catalyst, and there is no mixing of fine metal particles in the product as in the conventional method; ■ Reaction Since the surface is an active surface and contains atomic hydrogen, no coking (carbonization) occurs.

■The partition wall type catalyst of the present invention can simplify the structure of the conventional reaction vessel, thereby making it easier to rectify the reaction gas and improving the reaction efficiency; ■The partition wall type catalyst of the present invention Because it has high activity and high reaction selectivity, high productivity can be obtained even with a smaller active surface area than ordinary metal catalysts.

The obtained product can be recovered from unreacted raw materials by methods such as distillation and extraction.

However, since the barrier wall type catalyst of the present invention has a small surface area and active sites are exposed, it has the disadvantage that it is easily affected by catalyst poisons. Therefore, in order to realize a reaction system with high activity and high reaction selectivity, the reaction chamber side of the partition wall type catalyst is coated with a transition metal from Group 8 of the periodic table to increase the resistance to catalyst poisons and reduce the reaction rate and catalyst life. In order to prevent the decrease or to further enhance the reaction selectivity, an alkali metal or alkaline earth metal may be further dispersed or applied as a cocatalyst onto the coating.

Further, in order to increase the actual area of the interface of the partition type catalyst of the present invention, at least one end of the cross section of the catalyst can be made uneven.

[Example] The partition type catalyst of the present invention and the reaction apparatus for the catalyst will be explained below by giving examples.

One side of the stool also contains raw materials with a LaNis-Ni eutectic composition (21% by weight of La,
Ni (79% by weight) was placed in an alumina crucible with a diameter Losm and a length of 100 mm, and heated in an electric furnace with a large temperature gradient (
A hydrogen storage alloy ingot was obtained by unidirectional solidification at a rate of 3.9μ/sec at a maximum temperature of 1400°C at the center to grow an aligned structure. This ingot was cut in a direction perpendicular to the growth direction of the structure to obtain a disk-shaped partition type catalyst (effective reaction surface mo, 307 cm") with a diameter of 10ffiI11 and a thickness of 5IIIM. Here, the effective reaction area is: This refers to the total area of the interior that is shielded from the exterior by a copper gas get.

Next, the partition type catalyst obtained as described above was attached to the reactor as shown in Figure 2, and the entire reactor including the hydrogen supply chamber (A) and reaction chamber (B) was immersed in a water bath. The chamber was heated to 80°C and the chamber was evacuated for 30 minutes.
Hydrogenation was performed at 0° C. and a hydrogen pressure of 0.5 MPa for 1 hour. By repeating this operation five times, both sides of the partition type catalyst were activated.

Next, hydrogen is supplied from the conduit (5) to the hydrogen supply chamber (A) at a hydrogen supply pressure of 0.15 to 0.7 MPa, while a mixed gas of ethylene and hydrogen (hydrogen content Pressure 0.9
) is used as a charging material and the conduit (6
), and the hydrogenation reaction of ethylene was carried out under the temperature conditions listed in Tables 1 and 2. In order to confirm the life of the catalyst, the reaction rate was measured after 400 minutes of use at the initial stage of use and after 12 days of use after long-term use.

The resulting product stream was analyzed by FID gas chromatography to determine the reaction rate. The results are shown in Tables 1 and 2.

Turtle 1 Shishi - Reaction temperature = 40℃ (after 400 minutes of use) - Moxibustion (12
(After continuous use for days) The surface area was approximately twice that before electrolytic treatment. The partition type catalyst was installed in the apparatus shown in Fig. 2 so that this cross section was on the reaction chamber side, and the activation treatment was performed in the same manner as in Example 1, and the reaction conditions were also the same as in Example 1. did.

Daiichi-1-jl Reaction temperature = 40℃ An example of improving the activity of a partition wall type catalyst by surface modification is shown.

1 of the partition type catalyst similar to that obtained in Example 1 above.
The cross section is treated by constant potential electrolysis to preferentially electrolytically remove Ni on the cross section, resulting in an uneven surface. [Effects of the Invention] Unsaturated hydrocarbons and The hydrogenation process of unsaturated hydrocarbons in the liquid phase is in principle exactly the same; therefore, the effect of the barrier wall catalyst confirmed by the hydrogenation reaction of ethylene to ethane in the gas phase is similar to that of the liquid phase catalyst. It can be expected that it will be as effective as mochi in the hydrogenation of unsaturated hydrocarbons in the phase. Therefore, by using the partition type catalyst of the present invention for coal liquefaction, upgrading of liquefied petroleum, and reforming of heavy oil, it is possible to improve reaction efficiency and simplify the reaction equipment (high viscosity simplification of the device structure for reaction treatment of reactants) is possible.

[Brief explanation of drawings]

FIG. 1 is a schematic cross-sectional view of the partition wall type catalyst of the present invention, and FIG. 2 is a schematic diagram of the device of the present invention.
Ni, 2...Ni, 3...barrier type catalyst, 4...
Copper gasket, 5... Conduit, 6... Conduit, 7...
·conduit. Old drawings (no changes in content) Figure 1 Figure 2

Claims (1)

[Claims] 1. A hydrogen storage alloy ingot made of a LaNi_5-Ni eutectic alloy grown with an aligned structure through unidirectional solidification was cut into predetermined dimensions in a direction perpendicular to the growth direction of the structure. A partition wall type catalyst characterized by its plate shape. 2. At least one end of the cross section of the partition wall type catalyst is coated with a transition metal from Group 8 of the periodic table as an activity promoter for hydrogenation and hydrocracking reactions, or an alkali metal or an alkali metal is further coated on the coating as a co-catalyst. 2. The partition wall type catalyst according to claim 1, which is coated with an alloy in which an alkaline earth metal is dispersed and added. 3. The partition wall type catalyst according to claim 1 or 2, wherein at least one end of the cross section of the partition wall type catalyst is uneven to increase the actual area of the interface. 4. A hydrogen supply chamber equipped with a hydrogen supply conduit, a reaction chamber equipped with a charge material flow conduit and a product flow conduit, and a catalyst section partitioning the hydrogen supply chamber and the reaction chamber, with one side of the catalyst cross section being in the hydrogen supply chamber and the other being in the reaction chamber. A partition wall type catalyst reaction device comprising a partition wall type catalyst installed in contact with each chamber, wherein the partition wall type catalyst according to any one of claims 1 to 3 is used as the partition wall type catalyst. Reactor for catalyst.