JPH0226801A - Method for reforming methanol - Google Patents

Abstract

PURPOSE:To stably obtain hydrogen-contg. gas having a high hydrogen concn. at a low temp. with high selectivity over a long time by bringing methanol and oxygen-contg. gas into a reaction in the presence of a specified catalyst. CONSTITUTION:0.01-10wt.% Pt and/or Pd is supported on a carrier (e.g., Al2O3) contg. >=1wt.% oxide of an alkaline earth metal (e.g., MgO) to obtain a catalyst. In the presence of the catalyst, 1mol methanol, 0.1-5mol oxygen-contg. gas and 0.01-10mol water are fed so as to regulate the flow rate of methanol to 0.1-10l/hr par 1l catalyst and they are brought into a reaction at 100-600 deg.C 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 more specifically, it relates to a method for reforming methanol, and more specifically, it reacts methanol with an oxygen-containing gas to produce a hydrogen-containing gas stably at low temperatures and over a long period of time. The present invention relates to a method for modifying methanol that can be produced.

[Conventional technology]

Methanol can be produced on a large scale from coal, natural gas, etc. via synthesis 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. is leaning.

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.

0 horse O■ → OO+2B, ■01!
, OII Touma o-4ao, + 311. ■Since the above reaction is endothermic, a heat source is required. Therefore, shell-and-tube reactors are generally used; however, the reaction tubes are filled with a catalyst, and broad heat is supplied by passing a heating medium outside the reaction tubes, which has the disadvantage of low thermal efficiency. be.

Furthermore, in terms of thermodynamic equilibrium, in order to achieve a conversion rate of 95% or higher, it is necessary to set the reaction temperature f to 250° C. or higher, which also poses the problem of taking time to start up.

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

OEmOH+v2ow (+2 N!) →002
+ 24 (+2 ”t) @ (HlOH-)-1
40-柟H*O(+n→ao,+iH,(+N!)
■In addition, in Japanese Patent Application Laid-open No. 52-156194, etc., the following partial oxidation reaction (■) and a catalyst for the reaction (γ
-Catalyst with Lii, Or, and Ou supported on alumina)
has been proposed, but it has been found that there are problems such as poor selectivity such as OH, (2) generation, and lack of long-term stability of the catalyst.

C111,OH+ (1150,-)-0,6N,→1
．． 65 horses + (L7500 + (110H, + α15H
,O+匡1500゜+IIL6N! [Means for solving the problem] Therefore, the present inventors have determined that the H of υ per 1 mot of methanol is
3 Reaction ■ in which the amount generated is 2 mol or more.

■ (In the above reaction ■, H1 generation amount t 65 mat )
We have developed a catalyst to selectively advance the process at low temperatures. 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 found that platinum, palladium, etc. The present inventors have discovered that a catalyst on which a noble metal is supported has extremely excellent activity selectivity and durability in methanol reforming reactions (1) and (2), leading to the completion of the present invention.

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

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 °C Molar ratio of air supply to 1 mole of methanol: 11 to 5,
Particularly preferably [L5~2 molar ratio of water supplied to 1 mole of methanol: α01~1
0, particularly preferably 0.1 to 2 methanol supply jiz/h per 1 t of catalyst: IIL1
~10, particularly preferably [15~5 The carrier containing an oxide of an alkaline earth metal element is a support containing an oxide of an alkaline earth metal element in at least one tqb
Preferably, the carrier contains 10 to 98% by weight (based on the total amount of the carrier), a substance other than the oxide of an alkaline earth metal element, and a carrier containing alumina, titania, zirconia, silica, and other binder components. point to

- For example, MgO-me 40. , Mg0-Ti
e.

0aO-mu40. ．． 0aO-stot, BaO-
M40. ．． There are combinations such as BaO-ZrO.

MgO-me40. The preparation method will be explained using a carrier as an example: (1) An alumina carrier is immersed in an aqueous magnesium nitrate solution.

■ Mix MgO, Mg0O, etc. with alumina sol.

■ An alkali such as soda carbonate is added to a mixed solution of an aqueous solution containing an MB compound and an aqueous solution containing a MU L compound to form a precipitate.

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

Next, platinum and/or palladium can be supported on the carrier obtained in this manner by conventionally used methods, such as platinum and/or palladium compounds such as nitrates, chlorides, ammine complexes, etc. A catalyst on which platinum and/or palladium is supported can be obtained by immersing the carrier in an aqueous solution of , calcining it, and then subjecting it to hydrogen reduction treatment.

The amount of platinum and/or palladium supported (based on carrier) is 10
1 to 10]iji% is preferable.

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] Magnesium oxide powder and alumina sol were mixed, dried and fired at 500°C for 3 hours to achieve a weight ratio of MgO and 40 m of aluminum of 9.
A 0:10 MgO-me 40s support was obtained.

The carrier thus obtained was immersed in an aqueous solution of tetraammine and platinum dichloride [chemical formula Pt(NU, )4ah], dried and then calcined at 500°C for 3 hours to form a CL5-1
% of platinum supported catalyst was prepared.

This catalyst was reduced at t-400° C. for 3 hours in a 4% hydrogen stream, and an activity evaluation test was conducted under the conditions shown in Table 1 to obtain the results shown in Table 2. As a comparison catalyst, a conventional γ-me 40. Comparative Catalyst 1 containing 5 parts by weight of platinum as a carrier, and 18 parts by weight of IIL, 3109 parts by weight of platinum, 0.
Comparative catalyst 2t supported at 5% by weight (based on carrier) was prepared,
Table 2 shows the results of the activity evaluation test at a reaction temperature of 3ooc.
It is also shown in .

Table 2 A carrier was prepared so that the amount of platinum was 50.50, 70.95 parts by weight, immersed in an aqueous solution of chloroplatinic acid, and subjected to hydrogen reduction treatment to obtain a catalyst with platinum supported in an amount of (L5 parts by weight). 2
~61.

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 Note 1) Note 2) The cracked gas composition is methanol, water and air (N,.

0, ) are excluded (the same applies hereinafter).

Note that the methanol reaction rate (total) refers to the ratio of methanol that has undergone a decomposition reaction to the total methanol supplied.

[Run 2] Using the same method as for catalyst 1 prepared in Row 1, the MgO concentration (based on the total amount of support) was 10°. The CaO.mu401 carrier supported at a concentration of 10% by weight and 1% (based on the total amount of the carrier) was immersed in an acidic solution of dinitrodiamine platinum nitric acid and subjected to hydrogen reduction treatment, so that the platinum concentration was determined to be [Ll,l! +.

Catalysts 7 to 10 were supported to a concentration of α5.1 by weight, and catalysts 11.12 were supported by a similar method so that the palladium concentration became 111°LL5 by weight, and EaO was further supported on alumina at a concentration of 10 weight. Using a BaO-A40B carrier, the platinum concentration was 13% by weight and the palladium concentration was 12% by weight.
A catalyst 13 was prepared which was supported 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 500°C.
I got the result.

Table 4 Catalyst 9 was subjected to a durability test for about 4000 hours, but no decrease in activity was observed.

〔Effect of the invention〕

As is clear from the above examples, by using the present invention, a hydrogen-containing gas with a high hydrogen concentration can be produced stably for a long time with good selectivity at low temperatures from a gas containing methanol and oxygen. I can do it.

Claims (1)

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