JPH02116603A - Method for reforming methanol - Google Patents

Abstract

PURPOSE:To stably obtain hydrogen-contg. gas having a high hydrogen concn. for a long time by allowing methanol to react with oxygencontg. gas in the presence of a catalyst obtd. by supporting Pt and/or Pd on a carrier contg. the oxide of a rare earth element. CONSTITUTION:A carrier such as alumina is immersed in an aq. soln. contg. the oxide of a rare earth element such as La2O3, taken out, dried and calcined to obtain a carrier contg. >=1wt.% oxide of the rare earth element. This carrier is immersed in an aq. soln. contg. a Pt compd. such as Pt(NH2)4Cl2 and/or a Pd compd., taken out, calcined and optionally subjected to reduction treatment with hydrogen to obtain a catalyst supporting 0.01-10wt.% Pt and/or Pd. Methanol is allowed to react with oxygen-contg. gas in the presence of the catalyst.

Description

[Detailed Description of the Invention] [Industrial Application Field] The present invention relates to a method for reforming methanol, and in particular to a method for reforming methanol, in which methanol and oxygen-containing gas are reacted to produce hydrogen-containing gas stably at low temperatures and over a long period of time. Regarding modification methods.

[Conventional technology]

Methanol can be produced on a large scale from coal, natural gas, etc. via synthetic gas, and is easy to transport, so it is of great interest in the future as an energy source to replace petroleum or as a raw material for various chemical industries. ing.

One method of using it is to reform methanol into a hydrogen-containing gas and use this as a pollution-free fuel for automobiles or fuel for fuel cells.

[Problem to be solved by the invention]

As a reaction to produce hydrogen-containing gas from methanol,
Generally the following reactions are used.

Since the above reaction is an endothermic reaction, a heat source is required. Therefore, a multi-tubular reactor is generally used, but the reaction heat is supplied by filling the reaction tube with a catalyst and passing a heating medium outside the reaction tube, which has the disadvantage of low thermal efficiency. Furthermore, in terms of thermodynamic equilibrium, in order to achieve a conversion rate of 95% or higher, the reaction temperature tends to be 250° C. or higher, and there is also the problem that it takes time to start up.

As a method for solving the above problems, a modification reaction using the following partial oxidation reaction can be considered.

CH30H+3AO1(+2Nri→Co,+2H,(+
2N,) -・-■CHsOH+y40m +3A H
zO(+N!) →Cot +, H yi(+Nt
) ”-■ Also, in JP-A-52-156194, etc., the following partial oxidation reaction ■ and a catalyst for the reaction (γ
-Catalysts with Ni, Cr, and Cu supported on alumina have been proposed, but it has been found that they have problems such as poor selectivity such as CH4 production and lack of long-term stability of the catalyst. Ta.

C) (30H+(Ll 50. +CL6N, 41.
65H! +Q, 75CO+(LI CH4+a15H,
0-1415co, 10(L6N!-...■ [Means for solving the problem]) Therefore, the present inventors determined that H2 per methano-A/1 moμ
We have developed a catalyst for selectively and at low temperatures the reactions ① and ② that generate 27μ or more (compared to 1.65μ/L/in the conventional reaction ②). Specifically, we focused on the fact that side reactions can be suppressed by making the support basic, and as a result of various experimental studies, we have developed a catalyst in which platinum and/or palladium is supported on a support containing an oxide of a rare earth element. However, the methanol reforming reaction ■.

In (2), it was discovered that the activity, selectivity, and durability were extremely excellent, and the present invention was completed.

That is, the present invention is characterized in that a method for producing a hydrogen-containing gas by reacting methanol and an oxygen-containing gas uses a catalyst in which platinum and/or palladium is supported on a carrier containing an oxide of a rare earth element. This is a methanol reforming method.

[Effect]

Preferred reaction conditions in the methanol reforming method of the present invention are as follows.

Reaction temperature: 100-600°C, particularly preferably 200-600°C
500℃ Air supply molar ratio to methanol-fv17~: α1~5
Particularly preferably 0.5 to 2 molar ratio of water to methanol/S/1 moM: (LO
1-10 Particularly preferably 0.1-2 Methanol supply per 1 L of catalyst ttAX: Q, 1-10 Particularly preferably α5-5 Here, the rare earth element oxide refers to a rare earth element of the Ina group of the periodic table. Oxides, such as funtan oxide (La
*Os), cerium oxide (Ce 02), neodymium oxide (Nd! 01), or a mixture thereof.

In addition, here, the carrier containing the oxide of a rare earth element is
A carrier containing an oxide of a rare earth element at least 1% by weight, preferably 10 to 98% by weight (based on the total weight of the carrier), and as a substance other than the oxide of a rare earth element,
Refers to materials containing mina, titania, zirconia, silica, and other binder components.

Examples include La201At201, La103-
Ti02, Ce01-A/403, Ce0l-
8101, Nd103-A/101, Nd403-
ZrOl.

There are combinations such as La2O2-CeO and Al4o3.

The preparation method using La20g-AI403 carrier as an example is as follows: 1) Immersing the Amina carrier in an aqueous solution of lanthanum nitrate; 2) Coating with Lag○s, Law(COs)s, etc.
Mix with.

■ Add an alkali such as carbonated soda to a mixture of an aqueous solution containing a La compound and an aqueous solution containing a kA compound to form a precipitate.

After any of the above steps, it can be easily obtained by drying and firing.

Next, the method of supporting platinum and palladium on the carrier obtained in this way can be any conventionally used method, such as a water bath of a compound such as platinum and/or palladium nitrate, chloride, ammine complex, etc. After immersing the carrier in the liquid, it is calcined and further subjected to hydrogen reduction treatment to obtain a catalyst on which platinum and/or palladium is supported.

The supported amount of platinum and/or palladium (based on carrier) is (
A range of 101 to 10% is preferred.

The catalyst obtained as described above has high selectivity and activity for the reaction of methanol and oxygen-containing gas to produce hydrogen-containing gas, and has extremely excellent durability. It is something.

Hereinafter, the present invention will be specifically explained using examples.

[Example 1] Lanthanum oxide (Law's) powder and amimina sol were mixed, dried and fired at 500°C for 5 hours to form La403 and Al.
40s weight ratio 90:10 Lag 03” A4
03 carrier was obtained.

The carrier thus obtained was immersed in an aqueous solution of tetraammine and platinum dichloride [chemical formula Pt (NH2)4CI4], dried and then calcined at 500°C for 3 hours to obtain (L 5
Catalyst 1 supporting tB% of platinum was prepared.

This catalyst was reduced at 400° C. for 3 hours in a 4% hydrogen stream, and an activity evaluation test was conducted under the conditions shown in Table 1. The results shown in Table 2 were obtained. As comparative catalysts, Comparative Catalyst 1 in which 15% by weight of platinum was supported on a conventional γ-AI403 carrier, and CuO1
8% by weight, NiO9iii%.

Comparative catalyst 2 supported with 20g Cr 3% (based on carrier)
was prepared and subjected to an activity evaluation test at a reaction temperature of 300°C. The results are also shown in Table 2.

[Example 2] In the same manner as Catalyst 1 prepared in Example 1, La! The concentrations of 03 (based on the total amount of carrier) were 1030.50 and 70.
A carrier is produced as a by-product with a weight of 95% by weight and 1t%, which is immersed in a chloroplatinic acid aqueous solution and subjected to hydrogen reduction treatment to reduce platinum to 13% by weight.
Catalysts 2 to 6 were prepared which were supported so as to have a coulometric percentage.

Regarding these catalysts, an activity evaluation test was conducted under the conditions shown in Table 1 except that the reaction temperature was 300°C, and the results shown in Table 3 were obtained.

Table 3 [Example 3] An alumina carrier was immersed in a cerium nitrate aqueous solution, dried, and calcined to support a Ce01 concentration of 10% (based on the total amount of the carrier). After immersion and hydrogen reduction treatment, the platinum concentration was reduced to α1. (L3.Q, 5゜Catalysts 7 to 10 supported so as to be 1% directly, and catalyst 1112 supported so that the Baodium concentration was (Ll, α5% by weight) in a similar manner.
Catalyst 13 was prepared by using a NdOs-ATOs carrier in which NdtOs was supported on alumina in an amount of 6% by weight and 10% by weight to give a platinum concentration of 13% by weight and a platinum concentration of 12% by weight.

Activity evaluation tests were conducted on these catalysts under the same conditions as shown in Table 1, except that the reaction temperature was 300°C, and the results shown in Table 4 were obtained.

Table 4 Note that although a durability test of about 4000 hours was conducted on Catalyst 9, no decrease in activity was observed.

〔Effect of the invention〕

According to the present invention, a hydrogen-containing gas with a high hydrogen concentration can be produced stably for a long time with good selectivity at a low temperature from a gas containing methanol and oxygen! ! ! can be approached.

Claims (1)

[Claims] A method for producing a hydrogen-containing gas by reacting methanol and an oxygen-containing gas, characterized in that a catalyst in which platinum and/or palladium is supported on a carrier containing an oxide of a rare earth element is used. Method.