JP2001329273A - Apparatus for selective oxidation of carbon monoxide and method of removing carbon monoxide - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an apparatus for the selective oxidation of carbon monoxide in a wide temperature range with a high removing ratio of carbon monoxide in removing CO in a CO-containing mixed gas by selective oxidation. SOLUTION: The apparatus for the selective oxidation of carbon monoxide comprises a heat exchanger equipped with a heat transfer body 1, a refrigerant circulating within the heat transfer body 1, and a fin 6 formed on the surface of the heat transfer body 1; and a catalyst layer containing a carbon monoxide selective oxidation catalyst having an activity of carbon monoxide selective oxidation reaction, and the passage formed of the heat transfer body 1 and the fin 6 of the heat exchanger comes to a passage for a gas to be treated, and the above catalyst layer is formed on at least part of the surface of at least the fin of the above heat exchanger, and the surface on which the above catalyst layer is formed has been provided with surface-roughening treatment.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

The present invention relates to a catalyst for selectively oxidizing carbon monoxide and a method for removing carbon monoxide.

[0002]

2. Description of the Related Art A polymer electrolyte fuel cell has low pollution and high thermal efficiency, and is expected to be applied to a wide range of fields, such as a power source for automobiles and a distributed power source, as a low-temperature operation type fuel cell. A platinum catalyst is mainly used for the electrodes of this polymer electrolyte fuel cell. Since the platinum catalyst is easily poisoned by carbon monoxide (= CO), it is necessary to remove as much CO as possible from the fuel gas containing hydrogen as a main component. Fuel gas is
For example, a reformer is performed on a fuel such as methanol by a steam reforming reaction or a partial oxidation reaction to generate hydrogen,
CO shift reaction of CO by-product (reaction formula: CO + H ₂ O)
→ CO ₂ + H ₂ ).

However, the CO shift reaction alone has a limit in reducing CO due to restrictions on chemical equilibrium. For example, In one example of a component of the gas after CO-shift reaction when using methanol as fuel, H ₂ is 40 to 60%, CO ₂ is about 1
0%, about 20% H ₂ O and about 0.5% CO.
For this reason, in addition to the CO shift reaction, it is necessary to adopt a method for reducing the CO concentration to 100 ppm or less at which the polymer electrolyte fuel cell is not poisoned.

Accordingly, oxygen is added to the gas after the CO shift reaction, and a catalyst for selectively oxidizing carbon monoxide is used to selectively oxidize carbon monoxide in the gas to obtain 100 ppm. The removal method is considered below.

However, according to this method, the temperature of the catalyst rises due to the heat generated by the oxidation reaction of carbon monoxide,
As this catalyst becomes hot, the oxidation selectivity of carbon monoxide decreases and the oxidation reaction of hydrogen becomes dominant.Therefore, the problem is that the removal rate of carbon monoxide in the high temperature range is low and the applicable temperature range is narrow. Have.

On the other hand, Japanese Patent Laid-Open Publication No. Hei 5-43201 discloses a plate-type shift converter in which a shift reaction section filled with a low-temperature shift catalyst and a preheating section having a heat transfer promoting function are alternately stacked. Have been. However, according to the plate-type shift converter, since the distance between the catalyst and the heat transfer promoting function is large, it is not possible to sufficiently suppress the increase in the catalyst temperature due to the heat generated by the oxidation reaction of carbon monoxide. , A high carbon monoxide removal rate cannot be obtained.

[0007]

SUMMARY OF THE INVENTION An object of the present invention is to reduce CO2
It is an object of the present invention to provide a carbon monoxide selective oxidizing apparatus and a carbon monoxide removing method capable of obtaining a high carbon monoxide removal rate over a wide temperature range when CO in a mixed gas containing CO is selectively oxidized and removed.

[0008]

According to the present invention, there is provided a carbon monoxide selective oxidizing apparatus comprising a heat transfer member, a refrigerant circulating in the heat transfer member, and fins formed on a surface of the heat transfer member. A heat exchanger; and a catalyst layer including a carbon monoxide selective oxidation catalyst having a carbon monoxide selective oxidation reaction activity, wherein a flow path formed by the heat transfer body and the fins of the heat exchanger is a processing gas. Wherein the catalyst layer is formed on at least a part of the fin surface of the heat exchanger, and the surface on which the catalyst layer is formed is subjected to a surface roughening treatment. It is.

A method for removing carbon monoxide according to the present invention is directed to a heat exchanger including a heat transfer member, a refrigerant circulating through the heat transfer member, and fins formed on a surface of the heat transfer member; A catalyst layer comprising a carbon monoxide selective oxidation catalyst having a carbon oxide selective oxidation reaction activity, wherein the catalyst layer is formed on at least a part of at least a fin surface of the heat exchanger, and the catalyst layer is formed. Using a carbon monoxide selective oxidizing apparatus in which the surface to be treated is subjected to a surface roughening treatment, CO and O ₂ , an oxidizing agent, are passed through a flow path formed by the heat transfer body and the fins of the heat exchanger. The method is characterized in that CO in the processing gas is selectively oxidized and removed by the carbon monoxide selective oxidation catalyst by flowing a processing gas containing.

[0010]

DESCRIPTION OF THE PREFERRED EMBODIMENTS First, a carbon monoxide selective oxidation apparatus according to the present invention will be described.

The carbon monoxide selective oxidizing apparatus includes a heat exchanger including a heat transfer member, a refrigerant circulating in the heat transfer member, and fins formed on a surface of the heat transfer member; A catalyst layer containing a carbon monoxide selective oxidation catalyst having an oxidation reaction activity; a flow path formed by the heat transfer body and the fins of the heat exchanger becomes a flow path of a processing gas; The heat exchanger is formed on at least a part of a fin surface, and a surface on which the catalyst layer is formed is subjected to a surface roughening treatment.

As the processing gas, for example, H ₂ , C
A mixed gas containing O and O ₂ as an oxidizing agent can be given. This mixed gas may further contain water vapor.

The shape of the heat transfer body is, for example, a tube,
It can be a plate or the like.

[0014] The heat conductor can be formed of, for example, SUS, copper, aluminum, or the like. Among them, a heat conductor made of aluminum is preferable.

As the fins, for example, flat fins, corrugated fins, corrugated fins and the like can be used.

The fin can be made of, for example, SUS, copper, aluminum or the like. Among them, aluminum fins are preferable.

The temperature of the heat exchanger can be adjusted by a water-cooling method or an oil-cooling method.

The catalyst layer may be attached only to the fins, but is preferably attached to the heat transfer member together with the fins. When the catalyst layer is formed on the fin, it may be formed only on the outer surface of the fin, or may be formed on both the outer surface and the inner surface. On the other hand, when the catalyst layer is formed on the heat transfer body, it is desirable to form the catalyst layer on a part or the whole of the heat transfer surface among the surfaces.

On the roughened surface on which the catalyst layer is formed, the depth of the unevenness is preferably in the range of 1 to 200 μm. Here, the depth of the unevenness means the height of the convex portion. The height of the projection can be measured, for example, by an electron microscope. If the depth of the unevenness is less than 1 μm, it may be difficult to sufficiently increase the adhesion between the catalyst layer and the heat exchanger. On the other hand, if the depth of the unevenness exceeds 200 μm, the mechanical strength of the heat exchanger may be reduced.
A more preferable range of the depth of the unevenness is 2 to 100 μm.

When the surface of the aluminum fins and the surface of the aluminum heat conductor are subjected to a surface roughening treatment, an alumite treatment or a boehmite treatment can be employed for the surface roughening treatment.

The alumite treatment is performed, for example, by immersing the object to be treated in an electrolytic solution and applying an electric field to oxidize the surface to Al ₂ O ₃ . Examples of the electrolytic solution include sulfuric acid and oxalic acid. Further, since the surface on which the alumite treatment has been performed has an electrostatic effect, if a slurry described later is applied within 24 hours after the alumite treatment, the adhesion between the heat exchanger and the catalyst layer can be improved.

The boehmite treatment is performed, for example, by changing the surface of the object to be treated to boehmite (AlOOH) by hot water treatment. The following equation (A) shows a reaction equation in which aluminum is converted to boehmite (AlOOH) by the hot water treatment.

Al + 2H ₂ O → AlOOH + 3 / 2H ₂ (A) The catalyst layer is prepared by, for example, kneading a carbon monoxide selective oxidation catalyst, a binder and a solvent (for example, water) to prepare a slurry. It is formed by applying to a surface that has been subjected to a roughening treatment.

The carbon monoxide selective oxidation catalyst comprises: a carrier;
And an active species supported on the carrier.

Examples of the carrier include Y-type zeolite, mordenite, A-type zeolite, γ-type alumina, anatase-type titania, and crystalline silicate. Among them, crystalline silicate is preferable. This crystalline silicate, in a dehydrated state, the following (1)
In the powder X-ray diffraction using CuKα ray having the composition represented by the formula, the lattice spacing is 3.65 ± 0.1 °.
75 ± 0.1 °, 3.85 ± 0.1 °, 10.0 ± 0.0.
Peaks from the strongest peak to the fifth place appear at 3 ° and 11.2 ± 0.3 °.

(1 ± 0.8) R ₂ O. [aM ₂ O ₃ .bNO.cAl ₂ O ₃ ] .ySiO ₂ (1) wherein R is at least one element selected from the group consisting of alkali metals and H , M is at least one element selected from the group consisting of group VIII elements, rare earth elements, Ti, V, Cr, Nb, Sb and Ga, and N is Mg, Ca, S
at least one alkali metal earth element selected from the group consisting of r and Ba, and the molar ratios a, b, c and y are 0 ≦
a, 0 ≦ b ≦ 20, a + c = 1 and 11 ≦ y ≦ 3000
Is shown.

In the above crystalline silicate, CuKα
If the powder X-ray diffraction using X-rays does not show a peak at the above-mentioned five lattice spacings, or if it does not show a peak from the strongest peak to the fifth place, the selective oxidation property of carbon monoxide decreases. . The crystalline silicate shows peaks from the strongest peak to the fifth place in the above-described five lattice planes in powder X-ray diffraction using CuKα radiation, and has a lattice plane spacing of 3.0 ± 0.1 °, 3.3. ±
0.1 °, 4.25 ± 0.1 °, 5.6 ± 0.2 °,
It is preferable to show peaks at the sixth and subsequent positions at 6.0 ± 0.2 ° and 6.4 ± 0.2 °. More preferably, the lattice spacing is 3.05 ± 0.1 ° according to these peaks.
4.6 ± 0.1%, 5.7 ± 0.2 ° and 6.7 ± 0.
The peak is shown at 2Å.

The active species include, for example, Pt, Pd, R
It can be composed of at least one metal selected from the group consisting of u, Rh and Ir.

As the binder, for example, aluminum
(Al_TwoO_Three) And silica (SiO _Two)
At least one kind of metal oxide can be mentioned.

Next, a method of removing carbon monoxide using the above-described carbon monoxide selective oxidation apparatus will be described.

According to this method, the processing gas is passed through a flow path formed by the heat transfer element and the fins of the carbon monoxide selective oxidizing apparatus, and CO in the processing gas is converted by the carbon monoxide selective oxidation catalyst. Remove by selective oxidation.

As the processing gas, for example, H ₂ , C
A mixed gas containing O and O ₂ as an oxidizing agent can be given. This mixed gas may further contain water vapor (H ₂ O).

Since O ₂ in the mixed gas is for oxidizing CO, it does not need to be present together with hydrogen and carbon monoxide from the beginning. Therefore, in the present invention, H ₂
And an oxygen-containing gas is added to the gas containing CO and CO, and the resulting mixed gas is allowed to flow through the carbon monoxide selective oxidation device. As the oxygen-containing gas, for example, oxygen gas alone, air, or the like can be used.

The CO concentration in the mixed gas is preferably 4% or less. When the CO concentration exceeds 4%, the heat of combustion due to the combustion reaction of carbon monoxide may increase, and the heat removal of the heat exchanger may be insufficient.

It is preferable that the molar amount of the O ₂ gas in the mixed gas corresponds to 0.5 to 5 times the molar amount of the CO gas in the mixed gas. This is due to the following reasons. If the O ₂ gas molar amount is less than 0.5 times, a high carbon monoxide removal rate may not be obtained. On the other hand, if the O ₂ gas molar amount exceeds 5 times, the combustion reaction of CO (oxidation reaction of CO) occurs rapidly, so that the heat of combustion increases and the heat removal of the heat exchanger may be insufficient. A more preferred range is 0.5 to 3 times.

According to the carbon monoxide selective oxidizing apparatus and the carbon monoxide removing method of the present invention described in detail above, the following effects (a) and (b) can be obtained.

(A) By flowing the processing gas through the flow path formed by the heat transfer body and the fins of the heat exchanger,
Since the processing gas is in contact with at least the catalyst layer formed on the fin surface, CO in the processing gas can be selectively oxidized and removed by the carbon monoxide selective oxidation catalyst. In addition, since the heat generated by the selective oxidation reaction is removed by the heat conductor, a rise in the temperature of the catalyst layer can be suppressed. As a result, the selective oxidation reaction can be carried out by a soaking reaction, so that the selective oxidation of the catalyst can be prevented from decreasing with the progress of the selective oxidation reaction. Can be improved. In addition, since a high carbon monoxide removal rate can be obtained even when the temperature of the processing gas at the time of introduction into the carbon monoxide selective oxidizing apparatus is increased, the upper limit of the applied temperature of the processing gas can be increased. The applicable temperature range of the gas can be widened.

(B) The adhesion between the catalyst layer and the heat exchanger can be improved by forming the catalyst layer on the surface having irregularities by the roughening treatment. As a result, when the selective oxidation device is used in a state where shock such as vibration is applied, when it is used for a long time, or when the processing gas contains water vapor, the catalyst layer is separated. And high carbon monoxide removal efficiency can be maintained.

In the apparatus for selectively oxidizing carbon monoxide and the method for removing carbon monoxide according to the present invention, the fin is made of aluminum, and the surface on which the catalyst layer is formed is roughened by alumite treatment or boehmite treatment. Thereby, the adhesiveness between the catalyst layer and the fin can be further improved.

In the apparatus for selectively oxidizing carbon monoxide and the method for removing carbon monoxide according to the present invention, the catalyst layer is formed on at least a part of the surface of the heat conductor and at least a part of the surface of the fin. By performing the surface roughening treatment on the surface on which is formed, the contact area between the catalyst layer and the processing gas can be increased, so that the removal rate of carbon monoxide can be further improved.

In the apparatus for selectively oxidizing carbon monoxide and the method for removing carbon monoxide according to the present invention, the heat transfer body and the fins are made of aluminum, and the surface on which the catalyst layer is formed is subjected to alumite treatment or boehmite treatment. By roughening, the adhesion between the fin and the heat transfer body and the catalyst layer can be further improved.

In the apparatus for selectively oxidizing carbon monoxide and the method for removing carbon monoxide according to the present invention, by setting the depth of the irregularities on the roughened surface within the range of 1 to 200 μm, The adhesion between the catalyst layer and the heat exchanger can be improved without impairing the mechanical strength.

In the apparatus for selectively oxidizing carbon monoxide and the method for removing carbon monoxide according to the present invention, the crystalline silicate has hydrophobicity by using the above-mentioned crystalline silicate as a carrier of the catalyst for selective oxidation of carbon monoxide. Therefore, it is hardly affected by coexisting moisture, has a strong charge density distribution, and has pores having an optimal diameter of about 6 ° for CO adsorption, so that selective adsorption of polar substance CO can be promoted. As a result, the selective oxidation property of carbon monoxide can be improved, so that a high carbon monoxide removal rate can be obtained even when H ₂ coexists in the processing gas.

The carbon monoxide selective oxidizing apparatus and the carbon monoxide removing method according to the present invention are applied to, for example, purification of a gas containing hydrogen as a main component such as a fuel gas for a polymer electrolyte fuel cell. be able to.

That is, in order to obtain the fuel gas, first, hydrogen is produced from a fuel such as methanol, gasoline or methane by a reformer (for example, a steam reforming reaction or a partial oxidation reaction). The reformer gas contains CO ₂ , H ₂ O, and CO generated by a side reaction, in addition to the target substance H ₂ . This CO removal is performed in two stages. First, the CO concentration is reduced to a desired value by a CO shift reaction or the like. Next, an oxygen-containing gas is supplied to the gas, and the obtained mixed gas is introduced into the above-described carbon monoxide selective oxidizing apparatus. A high carbon monoxide removal rate can be obtained in a wide mixed gas temperature range. From the reformer gas in the region, a fuel gas for a polymer electrolyte fuel cell having a low CO concentration and a high hydrogen content can be obtained.

[0046]

Embodiments of the present invention will be described below in detail with reference to the drawings.

Example 1 First, a carbon monoxide selective oxidizing apparatus was assembled by the method described below.

1. Production of heat exchanger An aluminum heat exchanger was produced based on a heater core for an automobile. Both ends of the heat transfer tube of this heat exchanger have an outer surface area /
A corrugated louver fin having a volume (= Ap value) of 2000 m ² / m ³ was attached.

2. Surface treatment of heat exchanger The surface of this heat exchanger was subjected to alumite treatment under the following conditions.

(1) Alumite bath: sulfuric acid 300 g / L,
Dissolved aluminum 5 g / L, bath temperature 15 ° C (2) Current density: 2 A / cm ² (3) Electricity pattern: 1/3 load 1 minute, 2/3 load 1
(4) Sealing treatment: immersion in hot water at 100 ° C. for 20 minutes As a result of the alumite treatment by the above method, alumite (Al ₂ O ₃ ) was applied to the surfaces of the heat transfer tube and the fins. Growth was observed. The depth of the irregularities on the anodized surface is
It was 15 μm. The heat exchanger subjected to the alumite treatment was designated as a heat exchanger 1.

3. Preparation of Catalyst (Preparation of Carbon Monoxide Selective Oxidation Catalyst 1) Water Glass No. 1 (S
5616 g of water (iO ₂ : 30%) was dissolved in 5429 g of water. Meanwhile, aluminum sulfate 71
8.9 g, ferric chloride 110 g, calcium acetate 47.2
g, 262 g of sodium chloride and 2020 g of concentrated hydrochloric acid.
This solution was designated as solution B. The solution A and the solution B were supplied at a constant rate to form a precipitate, and the mixture was sufficiently stirred to obtain a slurry having a pH of 8. This slurry was charged into a 20-liter autoclave, and 500 g of tetrapropylammonium bromide was further added. The mixture was hydrothermally synthesized at 160 ° C. for 72 hours, washed with water, dried, calcined at 500 ° C. for 3 hours, and dehydrated. Crystalline silicate 1 having the composition shown in Table 2 described below was obtained in the wet state (without crystallization water).

The obtained crystalline silicate 1 was made of Cu
The powder X-ray diffraction measurement using Kα ray was performed, and the lattice spacing (d value) and the relative intensity of the peaks from the strongest line to the 15th position are shown in Table 1 below.

[0053]

[Table 1]

As is clear from Table 1, the crystalline silicate 1 has a lattice spacing of 3.65 ± 0.1%, 3.75 ± 0.1%, and 3.75 ± 0.1% in powder X-ray diffraction using CuKα radiation.
85 ± 0.1Å, 10.0 ± 0.3Å and 11.2 ±
0.3Å indicates the peak from the strongest peak to the fifth place,
3. lattice spacing 3.0 ± 0.1Å, 3.3 ± 0.1Å,
25 ± 0.1Å, 5.6 ± 0.2Å, 6.0 ± 0.2Å
And 6.4 ± 0.2 ° show peaks from the 6th to 11th positions, and 3.05 ± 0.1 °, 4.6 ± 0.1 °,
The peaks at the 12th to 15th positions were shown at 5.7 ± 0.2 ° and 6.7 ± 0.2 °.

The crystalline silicate 1 was replaced with 4N NH ₄ C
The aqueous solution was stirred at 40 ° C. for 3 hours to carry out NH ₄ ion exchange. After washing after ion exchange and drying at 100 ° C. for 24 hours, it was calcined at 400 ° C. for 3 hours to obtain H-type crystalline silicate 1.

100 parts of H-type crystalline silicate 1
(Carrier) was impregnated with an aqueous solution of chloroplatinic acid (H ₂ PtCl ₆ ) to support 0.4 parts by weight of Pt. After evaporating to dryness, the mixture was calcined at 500 ° C. for 5 hours to obtain Powder Catalyst 1. 3 parts of alumina sol (Al ₂ O ₃ : 10%) as a binder and silica sol 55
Parts (SiO ₂ : 20 parts) and 200 parts of water were added and sufficiently stirred to prepare a wash coat slurry.

Next, after the alumite treatment is performed, 4
After the elapse of 0 hours, the heat exchanger was immersed in the slurry, and the surfaces of the heat transfer tubes and the fins were subjected to an amount of catalyst of 40 per unit surface area.
g / m ² , to obtain a carbon monoxide selective oxidation apparatus having the structure shown in FIGS.

FIG. 1 is a perspective view showing a carbon monoxide selective oxidizing apparatus used in an embodiment of the present invention, and FIG. 2 is an enlarged cross-section showing a main part of a heat transfer tube and fins of the carbon monoxide selective oxidizing apparatus of FIG. FIG. 3 is a perspective view showing the fins of the carbon monoxide selective oxidizing apparatus of FIG.

That is, the carbon monoxide selective oxidation device includes a heat exchanger. This heat exchanger includes a plurality of Al heat transfer tubes 1 and a joint 2 for connecting the heat transfer tubes 1 to each other.
And a refrigerant storage tank 3 for storing a refrigerant flowing through the heat transfer tube 1. A refrigerant supply pipe 4 is connected to a lower part of the storage tank 3, and a refrigerant discharge pipe 5 is connected to an upper part of the storage tank 3. The refrigerant is supplied from the storage tank 3 to the lowermost heat transfer tube 1, flows from the heat transfer tube 1 toward the upper heat transfer tube 1, and is discharged from the refrigerant discharge tube 5. The corrugated louver fins 6 are attached to both surfaces of the heat transfer tube 1. The catalyst layer 7 includes the heat transfer tube 1
Are formed on the heat transfer surface subjected to the alumite treatment, and the outer surface and the inner surface of the fin 6 subjected to the alumite treatment.

(Preparation of Carbon Monoxide Selective Oxidation Units 2 to 24) In the method for preparing the crystalline silicate 1 in the method for preparing the carbon monoxide selective oxidation catalyst 1, instead of ferric chloride, cobalt chloride, ruthenium chloride or chloride was used. Rhodium, lanthanum chloride, cerium chloride, titanium chloride, vanadium chloride,
Except that chromium chloride, antimony chloride, gallium chloride or niobium chloride are each added in the same mole number as Fe ₂ O _{3 in} terms of oxide, the crystalline silicates 2 to 12 are prepared in the same manner as the crystalline silicate 1 described above. Prepared.

In the method for synthesizing crystalline silicate 1, except that magnesium acetate, strontium acetate or barium acetate is added in the same molar amount as CaO in terms of oxide, respectively, instead of calcium acetate, the above-mentioned crystalline silicate 1 is used. Crystalline silicate 1 in the same manner as 1
3 to 15 were prepared.

Further, the H-type crystalline silicate 1 is impregnated with palladium chloride, rhodium chloride, ruthenium chloride or iridium chloride instead of chloroplatinic acid, and each metal is added to the H-type crystalline silicate 1 by 0.4%. The catalyst was supported by weight, and evaporated to dryness, and then calcined at 500 ° C. for 5 hours to prepare Powder Catalysts 16 to 19.

Instead of H-type crystalline silicate 1, H-type Y-type zeolite, H-type mordenite, C-type
Powder catalysts 20 to 24 were prepared in the same manner as in Powder catalyst 1 described above, except that a type A zeolite, γ type Al ₂ O ₃ or anatase type TiO ₂ powder was used.

A catalyst slurry was prepared by using each of the powdered catalysts 2 to 24 in the same manner as described in the above-described selective oxidation apparatus 1 for monoxide. Next, the heat exchanger 40 hours after the alumite treatment was performed was immersed in the slurry, and the surfaces of the heat transfer tubes and the fins were treated with an amount of catalyst of 4 per unit surface area.
0 g / m ² , and covered with the catalyst layer described above with reference to FIGS.
The carbon monoxide selective oxidation devices 2 to 24 having the structures shown in the following were obtained.

Example 2 A heat exchanger similar to that described in Example 1 was prepared, and the surface of the heat exchanger was subjected to boehmite treatment under the following conditions.

(1) Pretreatment: The heater core heat exchanger is sufficiently degreased.

(2) Immerse the heat exchanger in hot water at 90 to 95 ° C. for 5 minutes.

After the immersion of (2), water was sufficiently removed, and the plate was allowed to stand at room temperature. The surface irregularities of the heat transfer tubes and the fins were measured to find that a boehmite layer having a depth of 5 μm was formed. It was confirmed. The heat exchanger subjected to the boehmite treatment was designated as a heat exchanger 2.

After a lapse of 40 hours from the boehmite treatment, a catalyst layer containing the powdered catalyst 1 was provided on the surfaces of the heat transfer tubes and the fins of the heat exchanger 2 in the same manner as described in Example 1 above. The carbon monoxide selective oxidation device 25 was formed.

(Example 3) The powder catalyst 1 was placed on the surfaces of the heat transfer tubes and the fins of the heat exchanger 1 after the elapse of 5 hours and 24 hours after the same alumite treatment as described in Example 1 described above. Is formed in the same manner as described in the first embodiment, and the carbon monoxide selective oxidation devices 26 and 27 are formed.
Was prepared.

(Comparative Example 1) The catalyst layer containing the powdered catalyst 1 was provided on the surfaces of the heat transfer tubes and the fins of the heat exchanger without surface treatment (this heat exchanger is referred to as the heat exchanger 3). 1
The comparative device 1 was formed in the same manner as described above.

Table 2 below shows a list of the above-described selective oxidation devices 1 to 27 and the comparison device 1.

[0073]

[Table 2]

Comparative Example 2 Powder catalysts 1, 2, 3, 18, and 19 described in Example 1 were prepared, and a slurry was prepared in the same manner as in Example 1 described above. Normal cordierite honeycomb substrate ハ Outer surface area /
The same volume (Ap value) as in Example 1 was coated with each slurry, and cordierite-based catalysts without heat exchanger (Comparative catalysts 2 to 6) were prepared.

The obtained carbon monoxide selective oxidation devices 1 and 2
7, Table 3 below for Comparative Device 1 and Comparative Catalysts 2 to 6
An activity evaluation test was carried out under the conditions shown in (1). At this time, the CO concentration at the catalyst layer outlet was continuously monitored by a ND-IR type CO system, and the stabilized CO concentration was measured. Table 6 shows the temperature of the catalyst present in the vicinity.
Shown in

[0076]

[Table 3]

Further, for the carbon monoxide selective oxidation devices 1 to 27 and the comparative device 1, in order to evaluate the adhesion of the catalyst layer to the heat exchanger, the temperature was repeatedly raised and lowered in an electric furnace, and the high flow rate gas forced stripping was performed. The test was performed, and the results are shown in Table 6 below. The test conditions are shown in Tables 4 and 5 below.

[0078]

[Table 4]

[0079]

[Table 5]

For the carbon monoxide selective oxidizing devices 1 to 27 and the comparative device 1 which were subjected to the above-mentioned temperature rise / fall repetition test and the forced peeling test, the amount of the peeled catalyst was measured, and the peeling rate of the catalyst was calculated. It is shown in Table 6.

[0081]

[Table 6]

As is clear from Table 6, in the carbon monoxide selective oxidation apparatuses 1 to 27 in which the catalyst layers were formed on the roughened surfaces of both the heat transfer bodies and the fins, the catalyst temperature at the catalyst layer inlet was 110 ° C. It can be seen that CO can be efficiently removed at any of the temperature of 160 ° C, 160 ° C and 230 ° C. Further, it can be seen that the carbon monoxide selective oxidation devices 1 to 27 have a higher adhesion strength of the catalyst layer than the comparative device 1 in which the catalyst layer is formed on the surface that is not roughened. In particular, the carbon monoxide selective oxidizer 2 having a catalyst layer formed within 24 hours after the alumite treatment
6 and 27 indicate that the catalyst stripping rate can be minimized.

On the other hand, the comparative catalysts 2 and 3 without the heat exchanger
6 shows that when the catalyst temperature at the catalyst layer inlet rises to 230 ° C., C
It can be seen that the O removal rate is extremely reduced and the temperature range in which CO can be efficiently removed is narrow.

[0084]

As described above in detail, according to the present invention, it is possible to provide a carbon monoxide selective oxidizing apparatus and a carbon monoxide removing method capable of obtaining a high carbon monoxide removal rate in a wide temperature range. .

[Brief description of the drawings]

FIG. 1 is a perspective view showing a carbon monoxide selective oxidation apparatus used in an embodiment of the present invention.

FIG. 2 is an enlarged cross-sectional view showing a main part of a heat transfer tube and fins of the carbon monoxide selective oxidation device in FIG.

FIG. 3 is a perspective view showing fins of the carbon monoxide selective oxidation device in FIG. 1;

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 ... Heat transfer pipe, 2 ... Joint, 3 ... Tank, 4 ... Refrigerant supply pipe, 5 ... Refrigerant discharge pipe, 6 ... Fin.

──────────────────────────────────────────────────続 き Continued on the front page (51) Int.Cl. ⁷ Identification code FI Theme coat ゛ (Reference) B01J 37/02 301 B01J 37/02 301K C01B 3/32 C01B 3/32 A H01M 8/06 H01M 8/06 GF term (reference) 4G040 EA02 EA06 EB14 EB32 EB33 FA04 FB04 FC07 FE01 4G069 AA03 AA08 BA01A BA01B BA02B BA04A BA04B BA07A BA07B BA17 BC01A BC02B BC09A BC09B BC10 BC30BBC BC BC BC BC BC BC BC BC BC BC BC BC BC55A BC55B BC58A BC58B BC65A BC66B BC67B BC69A BC70A BC71A BC71B BC72A BC72B BC74A BC74B BC75A BC75B BD01A CD10 DA06 EA06 EC22X EC22Y FA01 FA02 FA04 FB14 FB23 ZA03A ZA03B ZA04AZABA ZA04A ZA04A ZA04A ZB04A

Claims (8)

[Claims] 1. A heat exchanger comprising a heat transfer body, a refrigerant circulating in the heat transfer body, and fins formed on the surface of the heat transfer body; and a monoxide having a carbon monoxide selective oxidation reaction activity. A catalyst layer containing a carbon selective oxidation catalyst; wherein a flow path formed by the heat transfer body and the fins of the heat exchanger serves as a flow path of a processing gas; and the catalyst layer is at least one of the heat exchangers. A carbon monoxide selective oxidation device, wherein the surface is formed on at least a part of a fin surface and a surface on which the catalyst layer is formed is subjected to a roughening treatment. 2. The selective oxidation of carbon monoxide according to claim 1, wherein the fin is made of aluminum, and a surface on which a catalyst layer is formed is roughened by alumite treatment or boehmite treatment. apparatus. 3. The carrier of the carbon monoxide selective oxidation catalyst,
In a dehydrated state, it has a composition represented by the following formula (1), and has a lattice spacing of 3.65 ± 0.1Ｋ, 3.75 ± 0.1Å, and 3.75 ± 0.1 に お い て in powder X-ray diffraction using CuKα radiation.
85 ± 0.1Å, 10.0 ± 0.3Å and 11.2 ±
Crystalline silicate, a Y-type zeolite, an A-type zeolite, in which a peak from the strongest peak to the fifth position appears at 0.3 °;
2. The carbon monoxide selective oxidation apparatus according to claim 1, wherein the apparatus is at least one selected from the group consisting of mordenite, γ-type alumina, and anatase-type titania. (1 ± 0.8) R ₂ O. [aM ₂ O ₃ .bNO.cAl ₂ O ₃ ] .ySiO ₂ (1) where R is at least one element selected from the group consisting of alkali metals and H, and M is Group VIII element, rare earth element, at least one element selected from the group consisting of Ti, V, Cr, Nb, Sb and Ga, N is Mg, Ca, S
at least one alkali metal earth element selected from the group consisting of r and Ba, and the molar ratios a, b, c and y are 0 ≦
a, 0 ≦ b ≦ 20, a + c = 1 and 11 ≦ y ≦ 3000
Is shown. 4. The active species of the carbon monoxide selective oxidation catalyst is composed of at least one metal selected from the group consisting of Pt, Pd, Ru, Rh, and Ir. 3. The apparatus for selectively oxidizing carbon monoxide according to any one of 3. 5. The catalyst layer is formed on at least a part of a surface of the heat transfer body and at least a part of a surface of the fin, and a surface on which the catalyst layer is formed is subjected to a surface roughening treatment. The carbon monoxide selective oxidation device according to claim 1, wherein 6. The heat transfer body and the fins are made of aluminum, and a surface on which a catalyst layer is formed is roughened by alumite treatment or boehmite treatment. Carbon monoxide selective oxidizer. 7. The apparatus for selectively oxidizing carbon monoxide according to claim 1, wherein the depth of the irregularities on the roughened surface is in a range of 1 to 200 μm. 8. A heat exchanger comprising a heat transfer body, a refrigerant circulating in the heat transfer body, and fins formed on a surface of the heat transfer body; and a monoxide having a carbon monoxide selective oxidation reaction activity. A catalyst layer containing a carbon selective oxidation catalyst;
The catalyst layer is formed on at least a part of at least a fin surface of the heat exchanger, and the surface on which the catalyst layer is formed is subjected to a roughening treatment using a carbon monoxide selective oxidation device, By passing a processing gas containing CO and O ₂ that is an oxidizing agent through a flow path formed by the heat transfer body and the fins of the exchanger, CO in the processing gas is removed by the carbon monoxide selective oxidation catalyst. A method for removing carbon monoxide, which comprises removing by selective oxidation.