JPS5846346B2 - Methyl alcohol reforming catalyst - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a methyl alcohol reforming catalyst used for reforming methyl alcohol into a gas containing hydrogen and carbon monoxide.

Carbon dioxide, hydrocarbons, which are harmful substances emitted from internal combustion engines,
It is known that one way to reduce nitrogen oxides is to add hydrogen, which can burn stably over a wide range of air-fuel ratios, in order to operate the fuel at a leaner air-fuel ratio (mixing more air than the theoretical amount of air). It is being

One method for producing hydrogen to be added is to reform methyl alcohol.

This method uses heat from exhaust gas from an internal combustion engine to reform methyl alcohol.

As is well known, the exhaust gas heat of an internal combustion engine varies from near room temperature to about 300°C, so it can be reformed over a wide temperature range, and for example, it can be heated for a long time under the above-mentioned high temperature of about 800°C. It is necessary to have a catalyst that does not deteriorate its reforming performance even when placed in the catalyst, and that does not cause a decrease in strength due to the vibrations of the internal combustion engine, for example, when methyl alcohol is reformed using the exhaust gas heat of the internal combustion engine.

Conventionally, catalysts for reforming methyl alcohol include a Cu catalyst in which copper (hereinafter referred to as Cu) is supported on γ-alumina (hereinafter referred to as γ-A203), and Cu catalyst and nickel (hereinafter referred to as Ni) on γ-A1203. ) supported Cu-Ni
catalyst is known.

The above-mentioned conventional Cu catalyst, for example, can sufficiently reform methyl alcohol in a relatively wide temperature range in its initial state, but when used for more than 100 hours at a high temperature of about 700°C, γ-A■203 gradually changes. α-A1203
γ-A1203 begins to transform into α-A1203, and the crystal structure of a part of γ-A1203 changes, which weakens the bonding force between each atom and reduces its strength, making it more susceptible to wear due to vibration. The active surface area of A1□03 decreases,
In addition, there is a problem in that Cu particles undergo a half-melting phenomenon due to heat, the catalytic active area of Cu decreases, and the minimum reforming temperature of methyl alcohol shifts to a high temperature.

That is, conventional Cu catalysts have poor heat resistance and vibration resistance.

Note that although the conventional Cu-Ni catalyst also causes the same problems as the Cu catalyst, it has slightly better heat resistance than the Cu catalyst.

The present inventors have conducted various experiments in view of the above problem, and found that C.
Focusing on the fact that u-Ni catalysts have slightly better heat resistance than Cu catalysts, we have investigated various metals to prevent the half-melting phenomenon of Cu and Ni particles at high temperatures. ) was found through experiments to be suitable, and C
By adopting a new catalytic metal composition of u-Ni-Cr, it is possible to suppress the decrease in catalytic activity at high temperatures, and also to suppress the decrease in strength of γAl2O3 due to changes in the crystal structure of the γ-A1203 support at high temperatures. In order to prevent the active surface area from decreasing, various additives added to the catalyst metal composition were investigated. Silicon oxide (hereinafter referred to as SiO), strontium oxide (hereinafter referred to as Sro), cerium oxide (hereinafter referred to as CeO), It was discovered through experiments that one or more metal oxides selected from the group of lanthanum (hereinafter referred to as La2O3) and barium oxide (hereinafter referred to as BaO) is suitable, and the catalyst metal composition of the Cu-Ni-Cr mentioned above was r-A by adding one or more of the above metal oxides to
Strength reduction under high temperature of 12O2 and γ-A12
03 can be suppressed from decreasing in active surface area.

In summary, in the present invention, C
Three types of catalyst metals, u, Ni, and Cr, and Sin, S
By supporting a mixed composition with one or more metal oxides selected from the group of rO, CeO, La2O3, and BaO, the minimum reforming temperature of methyl alcohol shifts to a high temperature even when placed under high temperatures. It is possible to obtain a methyl alcohol reforming catalyst that has good heat resistance and strength resistance, and can suppress a decrease in strength and prevent wear due to vibrations and the like.

According to confirmation experiments conducted by the present inventors, after supporting the above metal oxide on γ-A1203, CuNi-Cr
When supported, a large amount of metal oxide is impregnated inside γ-A1203 during the process of supporting metal oxide on γ-A1203, and the particles of γ-A1203 are bonded together by the metal oxide, increasing the strength. However, on the other hand, there is a problem in that the micropores of γ-A1203 are blocked by impregnation with metal oxides, resulting in a decrease in active surface area.

Moreover, if the above metal oxide is supported after supporting Cu-Ni-Cr on γ-alumina, Cu-Ni-Cr
There is a problem that the catalytic action of metal oxides is inhibited by metal oxides.

The present invention will be explained below with reference to Examples.

Example 1 Cu(NO3)2・6H20, Ni(NO3)2・6H
5i(OC2H5)4 (ethylsilicate) is added to four kinds of solutions in which 20 and Cr(NO3)2.9H20 are mixed in the proportions shown in Table 1.

Next, a granular carrier made of γA1□03 (
Surface area 1.0 m/f? above) for 20 to 30 minutes, and then dried at 100°C to 120°C for 2 hours.

After drying, it is fired at 600°C for 2 hours to support a mixed composition of Cu0NiO-Cr203 and SiO on the surface of γ-A1203.

Fill a container with 94% or more of the catalyst prepared in this way, and heat the container to 800℃ for 10 to 200H2.
, a heating vibration test was conducted for 6 hours at an acceleration range of 10 to 15 G, and the relationship between the rate of weight loss (wt%) of the catalyst after this heating vibration test and the minimum reforming temperature of methyl alcohol was calculated using S i (QC2H5 ) We investigated how it changes depending on the amount of 4 added.

The results are shown in FIG. In Fig. 1, when reforming methyl alcohol for use as fuel in automobile internal combustion engines, the minimum reforming temperature of methyl alcohol is 200°C or less, and the amount of weight loss due to vibration is 0.25% or less (this value is approximately 50,000 kg).
The amount of Si(OC2H5)4 added to the solution of A1 is about 0.07 mol/l for A2, and 0.08 to 0.25 mol/l for A3, and 0.08 to 0.25 mol/l for A3. 06-0.14 mol/l, 0.05-0.0 for A4.
It can be seen that a range of 3 mol/l is suitable.

Also, as shown in Figure 1, S i (OC2H5)
As the amount of 4 added increases, the weight loss of the catalyst due to vibration decreases.

However, the minimum reforming temperature of methyl alcohol increases.

Note that the initial minimum reforming temperature of methyl alcohol before heating to 800°C was 200°C.

In addition, Cu0-Ni supported on the surface of γ-A12030
In O-Cr203-8jO, all CuO and NiO are reduced to Ni by hydrogen generated during reforming of methyl alcohol, but a portion of Cr2O3 is reduced to Cr, and SiO remains almost unchanged.

Cu exhibits catalytic action during methyl alcohol reforming.
-Ni-Cr is in a metallic state, and the amount of CuO-Ni0-Cr 203 supported on the surface of γ-A12030 (total 100% by weight) is 36-62% by weight for Cu, 8-32% by weight for Ni. % and Cr within the range of 18 to 41% by weight, methyl alcohol can be modified at 200°C or lower.

In addition, when SiO is converted to metal, the amount of four types of metals is Cu3
3-59% by weight, Ni 5-30% by weight, Cr15-39
% by weight, Si 1-10% by weight (However, Cu + Ni + C
r+5i=100% by weight), the minimum reforming temperature of methyl alcohol is 200° C. or lower, and there is little weight loss or wear due to vibration (high strength).

In addition, the amount of Cu-Ni-Cr-8i supported on γ-A1□03 is 0.10 to 0.4 relative to γA12031.
0% by weight is suitable.

If it is less than 0.10, the minimum reforming temperature of methyl alcohol becomes high and the strength becomes weak.

On the other hand, when it exceeds 0.40, it becomes easy to peel off from the surface of γ-AI203.

Comparative Example 0.5 mol of γ-A1203 in the same granular form as in Example 1 is immersed in the following S i (QC2H5)4 solution for 20 to 30 minutes, and then dried at 100° C. to 120° C. for 2 hours.

After drying, it is fired at 600° C. for 2 hours to support SiO on the surface of γA1□030.

Next, γ-A1203 carrying SiO on the surface is immersed in the solutions A1 to A4 in Table 1 shown in Example 1 for 20 to 30 minutes, and after immersion is dried at 100° C. to 120° C. for 2 hours.

After drying, it is fired at 600° C. for 2 hours to support the Cu0-NiO-Cr203 mixed composition on SiO on the surface of γ-A12030.

The catalyst obtained in this comparative example was subjected to the same heating vibration test as in Example 1, and the relationship between the minimum reforming temperature of methyl alcohol and the vibration resistance strength after this test is shown in FIG.

As can be seen from Fig. 2, when the minimum reforming temperature of methyl alcohol is 200°C or lower, the amount of weight loss due to vibration is 0.
Catalysts with less than 25% by weight cannot be obtained.

However, it can be seen that the vibration resistance characteristics are good.

The reason for this will be clear from the following explanation.

In the catalyst in Example 1, SiO is Cu0-NiO-Cr
203 and γ-A1203, and the crushing strength of the catalyst in Example 1 was Si (OC2H5)4
When the amount added was 0.1 mol/l, the amount was about 9 to 10 kg/crrf.

6-7 kg/ca for catalysts that do not support SiO;
Met.

On the other hand, the crushing strength of the catalyst in the comparative example was S 1
(QC2H5) Approximately 11 to 1 at an addition amount of 40.1 mol/l
It was 2 kg/crA.

In other words, in the catalyst in the comparative example, γ-A
Since SiO is supported on the surface of 1203, this SiO
A part of γ-A1203 is impregnated inside the SiO
enters between the particles of γ-A1203 and exhibits the effect of adhering the particles to each other (binder effect), so the crushing strength is large.

However, the high crushing strength indicates that the micropores of γ-A1203 are blocked by SiO impregnation, which reduces the active surface area.

Therefore, the catalyst in the comparative example has a high minimum modification of methyl alcohol.

Furthermore, a high crushing strength means that the vibration resistance is good.

Example 2 Ce (N
A catalyst is prepared using solutions having the compositions A1-A4 shown in Table 1 in the same manner as in Example 1 except that Oa)4 was used.

In addition, in the catalyst in this Example 2, r-Al
CuO-Ni0Cr203-CeO is supported on the surface of 2O3.

This catalyst was subjected to a heating vibration test similar to that in Example 1, and the relationship between the minimum reforming temperature of methyl alcohol and the abrasion weight loss rate after this heating test is shown in FIG.

In order to satisfy the minimum reforming temperature of methyl alcohol of 200°C and the weight loss due to vibration of 0.25% by weight, the amount of Ce (No s )4 added in the solution of Tsuta 1 must be 0.05 to 0.05%.
0.08 mol/, l, 0.06 to 0.231 for A2
1 mol, 0.07 to 0.17 mol/l for A3, and 0.06 to 0.3 mol/l for A4.

After supporting CeO on γ-A1203, Cu0-NiO
The catalyst supporting -Cr203 could not lower the minimum reforming temperature of methyl alcohol to 200°C or lower.

In this example, the amount of Cu0-NiO-Cr203-CeO supported on γ-A1203 was 28 to 53% by weight of Cu, 3 to 24% by weight of Ni, and 3 to 24% by weight of Ni.
12 to 35% by weight of Cr, 4 to 30% by weight of Ce (however, C
u + Ni + Cr + Ce (100% by weight) is suitable.

Further, the amount of Cu-Ni-Cr-Ce supported on γ-A1203 is suitably 0.13 to 0.4% by weight relative to γ-A12031.

Example 3 A solution having the &1 to A40 composition shown in Table 1 was used in the same manner as in Example 1, except that Si(OC2H5)4 in Example 1 was replaced with Sr(NO3)2.4H20. to make a catalyst.

In this catalyst, CuO is added to the surface of γ-A12030.
-Ni0-Cr203SrO is supported.

This catalyst was subjected to a heating vibration test similar to that in Example 1, and the amount of weight loss due to vibration due to vibration was 0.2 at the minimum reforming temperature of methyl alcohol of the catalyst after this heating vibration test.
The amount of Sr(NO3)2.4H20 that satisfies 5% by weight added to the solutions &1 to A4 in Table 1 was investigated.

In the solution of A1, 0.05 to 0.08 mol/1. 0.06 to 0.18 mol/AA in solution 2, 0 in solution 3
．． 07-0.15 mol/L 0.06-0.06 for A4 solution
0.23 mol/l is suitable.

Note that after supporting SrO on γ-A1203, Cu0-
The catalyst supporting NiO-Cr203 could not lower the minimum reforming temperature of methyl alcohol to 200°C or lower.

In this example, Cu0 supported on γ-A1□03
The supported amounts of -NiO-Cr203-8r are 30 to 57% by weight of Cu, 3 to 27% by weight of Ni, and Cr1 in terms of metal.
4 to 38% by weight, Sr3 to 23% by weight (However, Cu +
Ni + Cr + Sr = 100% by weight).

In addition, the amount of Cu-Ni-Cr-8r supported on γ-A1203 is 0.11 to 0.4 relative to r-Al2O31.
3% by weight is suitable.

Example 4 S i (OC2H5)4 of Example 1 above was replaced with La(NO
3) A catalyst is prepared using solutions having the compositions &1 to A4 shown in Table 1 in the same manner as in Example 1 except that 26H20 was used.

In this catalyst, CuO-N is formed on the surface of γAl2O3.
io-Cr203La203 is supported.

This catalyst was subjected to a heating vibration test similar to that in Example 1, and after the heating vibration test, the minimum reforming temperature of methyl alcohol in the catalyst was 200°C, and the weight loss due to vibration was 0.2.
Table 1 of La(NO3)2.6H20 satisfying 5% by weight
The amounts of &1 to A4 added to the solution were investigated.

In solution A1, an amount added that satisfied both characteristics could not be obtained.

Suitable values are 0.06 to 0.10 mol/l for A2 solution, 0.07 to 0.09 mol/l for Rin 3 solution, and 0.06 to 0.13 mol/l for Ken 4 solution. There is.

Note that after supporting La2O3 on γ-A1203, Cu
The catalyst supporting 0-NiO-Cr203 could not lower the minimum reforming temperature of methyl alcohol to 200°C or lower.

In this example, Cu0 supported on γ-A1203
The supported amount of -NiO-Cr203- is Cu in terms of metal.
31-59% by weight, Ni 3-28% by weight, Cr14-3
9% by weight, La 3-22% by weight (however, Cu, Ni
+Cr +La = 100% by weight).

In addition, γ-A1203 of Cu-Ni-Cr-La
The loading amount for γ-A12031 is 0.10~
0.42% by weight is suitable.

Example 5 Si (QC2H5)4 of Example 1 above was replaced with Ba(NO3
) A catalyst is prepared using solutions having compositions A1 to A4 shown in Table 1 in the same manner as in Example 1, except that Example 1 was changed to Example 1.

In this catalyst, Cu0- is on the surface of γ-A1203.
NiO-Cr203-BaO is supported.

This catalyst was subjected to a heating vibration test similar to that in Example 1, and after the heating vibration test, the minimum reforming temperature of methyl alcohol in the catalyst was 200°C, and the weight loss due to vibration was 0.2.
Table 10 1-A of Ba(NO3)2 satisfying 5% by weight
The amount of No. 4 added to the solution was investigated.

In the solutions A1-A3, addition amounts satisfying both of the above characteristics could not be obtained.

For A4 solutions, 0.07 to 0.09 mol/l is suitable.

In addition, after supporting BaO on r-Al2O3, Cu0N
The catalyst supporting iO-Cr203 could not lower the minimum reforming temperature of methyl alcohol to 200°C or lower.

In this example, Cu0 supported on γ-A1203
The carrying amount of -NiO-Cr203-BaO is 32 to 58% by weight of Cu, 5 to 29% by weight of Ni, and Cr1 in terms of metal.
4 to 38% by weight, Ba 1 to 17% by weight (however, Cu +
Ni + Cr + Ba = 100% by weight).

In addition, the amount of Cu-Ni-CrBa supported on γ-A1203 is 0.10 to 0, relative to γ-A12031.
41% by weight is suitable.

In addition, the above Sin, SrO, CeO, La2O3, B
Of course, two or more types of aO may be mixed into the Cu-Ni-Cr system.

As detailed above, in the present invention, γ-A1203
A mixed composition of three catalyst metals, Cu, Ni, and Cr, and one or more metal oxides selected from the group of Sin, SrO, CeO, La2O3, and BaO is supported on the surface of the methyl Since the alcohol reforming catalyst is configured, the minimum reforming temperature of methyl alcohol does not shift to a high temperature even if it is used for reforming methyl alcohol at a relatively high temperature for a long period of time, and strength reduction can be suppressed and vibration etc. This has the excellent effect of preventing wear and tear.

[Brief explanation of the drawing]

1 to 3 are characteristic diagrams for explaining the present invention.

Claims (1)

[Claims] 1. In the catalyst used to reform methyl alcohol into hydrogen-rich gas, copper, nickel,
and chromium, and one or more metal oxides selected from the group of silicon oxide, strontium oxide, cerium oxide, lanthanum oxide, and barium oxide. A catalyst for reforming methyl alcohol.