JPH04144902A - Reforming of methanol - Google Patents

Abstract

PURPOSE:To improve the conversion of methanol using a catalyst having excellent heat-conducting function by contacting methanol or a mixture of methanol and water with a specific catalyst. CONSTITUTION:The catalyst to be used in the present process is produced by kneading (A) 20-95wt.% of a mixture obtained by mixing one or more kinds of oxide selected from Cu, Zn and Cr oxides with Ni oxide at molar ratios CuO/NiO, ZnO/NiO and Cr2O3/NiO of 10/90-90/10 each, (B) 80-5wt.% of multiple oxides consisting of Zr and an oxide selected from alumina, titania and silica and (C) water, a binder and a deflocculant, spray-drying the kneaded mixture and spray-coating the obtained powder or granule to a metal or alloy material. The catalyst is filled in a reactor, hydrogenated by passing a gas containing 3-100% hydrogen at 200-500 deg.C and made to contact with methanol or a mixture of methanol and water under 0-30kg/cm<2>G pressure at 200-700 deg.C to obtain a hydrogen-containing gas containing >=50% H2, <=35% CO and <=25% CO2.

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 equations (1) and (2').

CH, DH-Co + 2H2 ΔH25℃= 21.7kcal/mol ・(
1) CHsOtl + ntl*o −(2+n
)Ha+(1-n)CD+nCmouth.

-(2) where 0<n<1 The methanol steam reforming reaction is as shown in the following equation (3).

CH30H+ l(, [l→CO2+382Δ825℃
= 11.8 kcal/mol ・(3) Conventional catalysts for reforming methanol include platinum metal elements such as platinum, copper, nickel, chromium, etc. on a carrier such as alumina.
Catalysts supporting base metal elements such as zinc and their oxides have 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 is converted into hydrogen-containing gas through a catalytic reaction with the catalyst. It is reformed into. This reforming reaction has a large endothermic reaction, and the necessary reaction heat is supplied from the heating medium on the shell side, but since the heat transfer rate is not very high, the temperature in the catalyst layer is lowered by the reaction heat, and the reaction rate is The problem is that it is difficult to make it large.

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 a method for producing hydrogen-containing gas from methanol or a mixture of methanol and water, in which a composite oxide containing zirconia contains one or more oxides of the group consisting of copper, zinc, and chromium, and an oxide of nickel. This is a methanol reforming method characterized by using a catalyst prepared by thermally spraying powder or granules obtained by spraying on a metal or alloy material.

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 catalytic function can be achieved 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 powder or composite oxide containing zirconia containing one or more oxides of the group consisting of copper, zinc, and chromium and nickel oxide on the surface thereof. The granules are welded by thermal spray coating.

The powder in which a composite oxide containing zirconia contains one or more oxides of the group consisting of copper, zinc, and chromium and an oxide of nickel is as follows. First, the composition of the catalyst component is Cu/N in the combination of an oxide of the group consisting of copper, zinc, and chromium and nickel oxide.
iO.

ZnO/NiO, Crz mouth, /NiRO on 10/9
A range of 0 to 90/10 (hereinafter expressed as molar ratio) is appropriate, and a range of 20/80 to 60/40 is particularly preferred.

In combination with two types of CuO, ZnO, and CrJ3, CuO-2nO, CuO-Cr2L, Zn[1
-The ratio of Cr2L to NiO is 10/90 to 90/10
The range is preferably CuO, ZnO, Cr*Oa
In combination with three types, the ratio with NiO is 10
The range of /90 to 90/10 is preferable. Next, the composition of the catalyst is the above catalyst components (CuO, ZnO.

A mixture of one or more types of Cr2O3 and NiO) and a composite oxide containing zirconia in a weight ratio of 20/80 to 9515
A range of 40/60 to 80/20 is particularly preferred. Here, the complex oxide containing zirconia is a complex oxide containing zirconia and one or more of the group consisting of alumina, titania, and silica. Usually, a mixed aqueous solution of salts of each metal is hydrolyzed with aqueous ammonia. It is prepared by firing the product and has a specific surface area of 0.1 to 500 m'/g. In addition, the composition of the composite oxide containing zirconia of the present invention is one of the group consisting of alumina, titania, and silica, and in combination with zirconia, Al2O5/ZrO2, T+02/Z
rO2, Si mouth z/ZrO2 10/90 to 90/10
The appropriate range is Al20a, Ti, ,
In combination with two types of Sin, Al2O3・
TlO2, Al2O3・5ins.

The ratio between TlO2・SiO□ and Z"0. is 10/90
A range of ~90/10 is preferred, and ^120-.

In combination with TlO2 and Sin□, Z
The ratio to rO2 is preferably in the range of 10/90 to 90/10.

To prepare a powder in which one or more oxides of the group consisting of copper, zinc, and chromium of the present invention are contained in a composite oxide containing nickel oxide and zirconia, a composite oxide containing the above metal compound and zirconia is prepared. A method in which a hydroxide or carbonate of an alkali metal element or an alkaline earth metal element is mixed as a precipitant with an aqueous solution of an oxide, or an aqueous solution, or aqueous ammonia, etc. is mixed to form a precipitate, which is then dried and calcined. etc. are used.

Furthermore, in the present invention, granulation for thermal spraying refers to mixing the powder prepared as described above with a predetermined amount of water, a binder, and a peptizer added to improve fluidity in the powder supply pipe of a thermal spraying machine. It 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/cjG, particularly preferably 0 to 15 kg/cofG Molar ratio of water supplied to 1 mole of methanol: 10 or less, particularly preferably 3 or less [Example] Hereinafter, the present invention will be specifically explained with reference to Examples.

[Example 1] 5I of 15+amX 70aumX 2m+ (thickness)
After thoroughly cleaning the JS 304 plate, powder flame spraying was performed on the SO3304 plate by supplying the nine types of powder shown in Table 1 to the powder supply pipe into a powder flame spraying machine, and then spraying catalysts 1 to 9.
was prepared.

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 also shown in Table 1.

Table Purity 99% Mon”H20/CHaOH=1.5 [mol/
moi] The composition of the produced gas (mo1% - composition excluding oao and CH308 on a dry basis, the same below)
was as follows.

(1) Methanol raw material H2: 64-67%, ('0: 31-33%, C02:
0.1-2%, CH: 0.02-2% (2) Methanol/water mixture raw material H: 66-71%, CO: 14-33%, CO2: 0
．． 5-14%, CH,: 0.01-1% [Example 2] In the same manner as in Example 1, the four types of powder shown in Table 3 were fed to a powder flame spraying machine to form catalysts 10-13. was prepared. These catalysts were charged into a reactor and heated at 200 to 350°C.
After performing the hydrogen reduction treatment for 12 to 16 hours, the catalyst activity was evaluated under the conditions shown in Table 4. The results are also shown in Table 3.

Table “HJ/CHsOH= 1.5 [mol/m]
The composition of the generated gas at each temperature was as follows.

(1) Reaction temperature 250℃, 300℃H,: 66-7
2%, CO: 13-33%, CD: 1-15
%, CH,: 0.01 to 1% (2) Reaction temperature
350°C H: 66-73%, CO: 8-33%, CL: 1-1
9%, CH,: 0.01-1% Furthermore, the above catalyst was added to the third
As a result of continuous testing for 1000 hours under the reaction conditions shown in the table (reaction temperature 350°C), the methanol conversion rate was 100%.
was constant.

[Example 3] In the powder preparation process of catalyst 6 in Example 1, ^l3s/Zr was used as the composite oxide containing zirconia.

Catalysts 14 to 18 (NiO:Cu0=7
A 0:30 molar ratio and a content of the zirconia-containing composite oxide in the catalyst of 20% by weight) were 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 5.

The composition of the generated gas was as follows.

(1) Methanol raw material Ha: 63-67%, CO: 30-32%, CO,i:
0.5-3%, C1: 0.1-3% (2) Methanol/water mixed raw material Ha: 64-71%, CO: 14-32%, CD:
1 to 14%, CHa: 0.05 to 2% [Example 4] Pipe outer wall of SOS 304 pipe with outer diameter 10.5 M, length 100 mm, catalyst outer surface area 33 ci (7) and thoroughly cleaned in advance Next, catalyst 19 was prepared by supplying the powder shown in Table 6 below to a powder flame spraying machine.

Using the catalyst 19 as a reaction tube, the temperature is raised by heating the inside of the reaction tube with a heat medium, and the temperature of the heat medium is 200 to 350°C.
After the reduction treatment was performed by supplying 34% 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 ()120/CH,OH=
1,5 (mol/mol)) to 15 [cc/h:l
As a result, the methanol reaction rate was 99%.

On the other hand, a conventional pellet-type catalyst was packed on the outside of a double tube so that the catalyst had the same external surface area, and the reaction was carried out in the same way as a reaction tube with a heating medium passing through the inside. As a result, 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 and therefore a high methanol reaction rate.

〔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, methanol can be used very effectively in a method for producing hydrogen-containing gas from a mixture of methanol and water. be done.

Claims (1)

[Claims] In the method of producing hydrogen-containing gas from methanol or a mixture of methanol and water, a powder or composite oxide containing zirconia containing one or more oxides of the group consisting of copper, zinc, and chromium and an oxide of nickel is used. A method for reforming methanol, characterized by using a catalyst in which granules are spray-coated on a metal or alloy material.