JPH0455301A - Method for reforming methanol - Google Patents

Abstract

PURPOSE:To effectively reform methanol with a catalyst having heat transferring function and catalytic function by converting the methanol into hydrogen- contg. gas with the catalyst obtd. by coating a metal with powder of a porous carrier contg. copper oxide by thermal spraying. CONSTITUTION:When hydrogen-contg. gas is produced from methanol or a methanol-water mixture, a catalyst obtd. by coating a metal or alloy material with powder of a porous carrier contg. copper oxide by thermal spraying optionally after granulation for thermal spraying is used. Since the catalytic component is supported on the metal or alloy material, high heat transferring function is ensured. Especially when the catalytic component is supported on a heat exchanger tube and methanol is reformed on the catalytic surface of the tube, heat transferring function and catalytic function can simultaneously be ensured and the methanol is effectively reformed.

Description

[Detailed Description of the Invention] [Industrial Application Field] The present invention relates to a method for reforming methanol, and more particularly, to a method for reforming and producing hydrogen-containing gas from methanol or a mixture of methanol and water. .

[Conventional technology]

In an effort to diversify fuels, methanol, which can be synthesized from fossil fuels other than crude oil, is attracting attention. Furthermore, since methanol is decomposed into hydrogen-containing gas at a much lower temperature than naphtha, it has the advantage that waste heat can be used as a heat source for methanol decomposition reactions and steam reforming reactions.

The methanol decomposition reaction is as shown in the following formulas (1) and (2).

CH3[IH-+CD +282 Δ825℃= 21.7kcal/mol ・・(
1) CtlsOH+nH2O-(2+n)Ha(1-
n) CO+nCO2·(2) where O<n<1 The methanol steam reforming reaction is as shown in the following equation (3).

CH3DH+ HJ→ CO2+ 3LΔH25℃=
11.8kcal/+ol ・(3) As a conventional catalyst for reforming methanol, platinum metal elements such as platinum or base metal elements such as copper, nickel, chromium, zinc, and their oxides are supported on a carrier such as alumina. A catalyst has been proposed. In addition to the above-mentioned metal support method, there is also a precipitation method, and a typical example of a catalyst prepared by this method is a methanol reforming catalyst containing zinc, chromium, and even copper. .

[Problem to be solved by the invention]

Conventionally, when decomposition or steam reforming reactions are carried out using methanol or a mixture of methanol and water as a raw material using the sensible heat of exhaust gas from engines, gas turbines, etc. as a heat source, the exhaust gas temperature ranges from 200°C to 700°C, as is well known. This is a reformer that can be reformed over a wide temperature range with a small amount of catalyst that can be installed in an internal combustion engine, and that does not deteriorate the reforming performance even if it is exposed to high temperatures of about 700°C as mentioned above. A method and a stable catalyst are needed.

As conventional catalysts for reforming methanol, catalysts prepared by the metal support method or precipitation method described above have been proposed, but these catalysts lack low-temperature activity and are prone to thermal deterioration. However, many problems remain.

In addition, the reactor is a shell-and-tube heat exchanger type, and the tube is filled with a catalyst, and the raw material methanol vapor or mixed vapor of methanol and water undergoes a catalytic reaction with the catalyst. Reformed to hydrogen-containing gas. This reforming reaction has a large endothermic reaction, and the necessary reaction heat is supplied from the heat medium on the shell side, but the heat transfer rate is not very high, so the temperature inside the catalyst layer is lowered by the reaction heat.
There is a problem in that it is difficult to increase the reaction rate.

In view of the above-mentioned state of the art, the present invention aims to provide a method for purposefully carrying out a methanol reforming reaction using a catalyst that has both a heat transfer function and a catalytic function.

[Means to solve the problem]

The present invention provides (1) a method for producing hydrogen-containing gas from methanol or a mixture of methanol and water, in which a powder containing copper oxide in a porous carrier is applied to a metal or alloy material as is or granulated for thermal spraying. A method for reforming methanol, which comprises using a catalyst that is thermally spray coated after the above treatment.

(2) In a method for producing hydrogen-containing gas from methanol or a mixture of methanol and water, powder containing two or more oxides from the group consisting of copper, zinc, and chromium in a porous carrier is used as a metal or alloy. A method for reforming methanol, characterized in that a catalyst is used as a material as it is or after being granulated for thermal spraying and then thermally spray coated.

It is.

In the above structure of the present invention, it is a preferable embodiment to use the heat exchanger tube itself as the metal or alloy material, and it is also a preferable embodiment to use a catalyst formed by coating the metal or alloy material after reduction treatment. It is something.

[Effect]

Since the catalyst component is supported on the metal or alloy material, it has a good heat transfer function. In particular, if methanol reforming is carried out on the catalytic surface of the heat transfer tube using a heat transfer tube carrying a catalyst component, both the heat transfer function and the catalyst function can be combined at the same time, making it extremely useful as a methanol reforming method. be.

The present invention will be explained in detail below.

The hydrogen-containing gas referred to in the present invention refers to hydrogen containing 50% or more, -
It is a gas containing 35% or less carbon oxide and 25% or less carbon dioxide.

Base metal materials include iron, copper, aluminum, zinc,
Cobalt, nickel, or an alloy thereof can be used, and a porous carrier containing copper oxide or two or more oxides from the group consisting of copper, zinc, and chromium on the surface of these powders can be used as is or After granulation for thermal spraying, it is welded by thermal spray coating.

The powder in which a porous carrier contains two or more oxides from the group consisting of copper, zinc, and chromium is as follows.

First, the composition of the catalyst component is ZnO/C in the combination of two or more oxides from the group consisting of copper, zinc, and chromium.
r20a, Zn[]/CuD, CrJs/Cu
A suitable range for O is 10/90 to 90/10 (hereinafter expressed as a molar ratio), particularly preferably a range of 20/80 to 80/20.

In the three combinations of CuO, ZnO, and Crabs, the ratio of ZnO・CrzL to CuD is 10:90 to
A range of 90:10 is suitable, especially 20/80 to 80
A range of /20 is preferred.

Next, the composition of the catalyst is determined by the above catalyst components (CuO, ZnO, C
r, 0. The weight ratio of two or more oxides or copper oxide) to the porous carrier is preferably in the range of 20:80 to 95:5, particularly preferably in the range of 30:0 to 80:20. Here, porous carriers include diatomaceous earth, alumina, silica, titania, zeolite, etc., and have a specific surface area of 0.1 to 500 m
2/g.

To prepare a powder containing two or more oxides of the group consisting of copper, zinc, and chromium or copper oxide in a porous carrier according to the present invention, a precipitating agent is added to an aqueous solution of the metal compound and the porous carrier. As a method, a method is used in which a hydroxide or carbonate of an alkali metal element or an alkaline earth metal element is used as it is or in an aqueous solution, or by mixing with ammonia water or the like to form a precipitate, followed by drying and calcining.

Furthermore, granulation for thermal spraying in the present invention refers to adding a predetermined amount of water, a binder, and a peptizer to the powder prepared as described above in order to improve its fluidity in the powder supply pipe of a thermal spraying machine. Knead,
Refers to granulation using the spray drying method.

Examples of thermal spray coating methods include powder flame spraying and plasma spraying.

In addition, as a pretreatment for carrying out the catalytic reaction in the present invention, a gas containing 3% to 100% hydrogen (inert gas balance) is passed over the catalyst at 200 to 500°C to reduce the metal composite oxide. Preferably, the treatment is carried out.

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

Reaction temperature = 200 to 700°C, particularly preferably 200 to 500°C, reaction pressure 0 to 30 kg/cnfG, particularly preferably 0 to 15 kg/cdG, molar ratio of water supplied to 1 mole of methanol: 10 or less,
Particularly preferably 3 or less [Examples] The present invention will be specifically described below with reference to Examples.

[Example 1] SO330 of 15UX 70mx 2+am (thickness)
After thoroughly cleaning the four plates, the 9 types of powder shown in Table 1 were supplied to the powder supply pipe of the powder flame spraying machine, and the above SO330
Perform powder flame spraying on 4 plates and apply catalysts 1 to 9! II.

After filling a reactor with the catalysts 1 to 9 and performing hydrogen reduction treatment at 200 to 350°C for 12 to 16 hours, catalytic activity was evaluated under the conditions shown in Table 2 below. The results are shown in Table 3.

Table 1 Purity 99% H20/CH30H= 1.5 (0101/lTl0
I) The composition of the generated gas (composition excluding H,0 and CH,011 on rno1%-dry basis, same hereinafter) was as follows.

(1) Methanol raw material H2: 64-67%, CO: 31-33%, CO2: 0
．． 1-2%, CH,: 0.02-2% (2) Methanol/water mixture raw material H2: 69-74%, CD=5-25%, Co,: 6
~21%, CH,: 0.01~1% [Example 2] In the same manner as in Example 1, the four types of powders shown in Table 4 were supplied to a powder flame spraying machine, and powder flame spraying was carried out. Do catalyst 1
0 to 13 were prepared. These catalysts were filled in a reactor and subjected to hydrogen reduction treatment at 200 to 350°C for 12 to 16 hours, and then the catalyst activity was evaluated under the conditions shown in Table 5.

The results are shown in Table 6.

Table 4 No. table No. table The composition of the generated gas at each temperature was as follows.

(1) Reaction temperature 250°C, 300°C H2 near 4-7
4.5%, CO: 1-5%, co: 21-24
%, CH,: 0.01-1% (2) Reaction temperature 350
°C H2 near 0-73%, CO: 8-21%, CO,: 9-
19%, CH,: 0.01-0.2% Furthermore, the above catalyst was added under the reaction conditions shown in Table 5 (reaction temperature 350°C) for 10%
As a result of continuous testing for 00 hours, the methanol conversion rate was constant at 100%.

[Example 3] Catalyst 14 was prepared in the same manner as in Example 1 except that alumina, silica, titania, or diatomaceous earth powder was used instead of zeolite as the porous carrier in the powder preparation step of Catalyst 1.
~16 (CuO-ZrO = 50:50 molar ratio, content of porous carrier in catalyst powder 50% by weight) was prepared.

These catalysts were subjected to hydrogen reduction in the same manner as in Example 1, and then their activity was evaluated. The results are shown in Table 7.

Table 7 The composition of the generated gas was as follows.

(1) Methanol raw material H2: 64-67%, CO: 31-33%, CO2: 0
．． 1-2%, CH,: 0.02-1% (2) Methanol/water mixed raw material H2: 69-74%, CO: 5-25%, CO2: 6-
21%, CHa: 0.01-0.1% [Example 4] External diameter 10.5111 m, length 10 which was sufficiently cleaned in advance
0mm, catalyst outer surface area 33ca! A catalyst 18 was prepared by supplying the powder shown in Table 8 below to the outer wall of the SO3304 pipe and performing powder flame spraying on the outer wall of the SO3304 tube.

Table 8 Using the above catalyst 18 as a reaction tube, the inside of the reaction tube is heated with a heat medium to raise the temperature, and the temperature of the heat medium is 200 to 350°C.
After the reduction treatment was performed by supplying 30% hydrogen (nitrogen balance) gas to the outer surface of the reaction tube, the heating medium was heated to a constant temperature of 350°C, and then on the outer surface of the reaction tube, 350℃
Mixed vapor of methanol and water (8,0/CH,OH~1
, 5 (mol/mol)) at a flow rate of 15 [:cc/h], the methanol reaction rate was 98%.

On the other hand, when a conventional pellet type catalyst was packed on the outside of a double tube so that the outside surface area of the catalyst was the same, and the reaction tube was conducted in the same way as a reaction tube through which a heat medium was passed between the inside and the inside, the methanol reaction rate was 90. % or less.

As a result, it was found that the reaction tube according to the present invention has a high heat transfer rate, so that the methanol reaction rate is high.

〔Effect of the invention〕

As is clear from the above examples, by using the catalyst with an excellent heat transfer function according to the present invention, a method can be carried out very effectively for producing hydrogen-containing gas from methanol or a mixture of methanol and water. provided.

Claims (2)

[Claims] (1) In a method for producing hydrogen-containing gas from methanol or a mixture of methanol and water, a powder containing copper oxide in a porous carrier is applied to a metal or alloy material as it is or after being granulated for thermal spraying. A method for reforming methanol, characterized by using a spray-coated catalyst. (2) In a method for producing hydrogen-containing gas from methanol or a mixture of methanol and water, powder containing two or more oxides from the group consisting of copper, zinc, and chromium in a porous carrier is used as a metal or alloy. 1. A method for reforming methanol, which comprises using a catalyst which is formed by using a material as it is or after being granulated for thermal spraying and then coated by thermal spraying.