JPS60209253A - Catalyst for manufacturing gas containing methane - Google Patents

Abstract

PURPOSE:To obtain a catalyst for manufacturing gas contg. methane which is high in selectivity and high in activity at low temp. and long in life by depositing Ni or nickel oxide on a carrier contg. the oxides of rare earth elements. CONSTITUTION:>=0.01wt% preferably 1-90wt% Ni or nickel oxide is deposited on a carrier (for example, alumina) contg. at least >=0.01wt% preferably 0.1- 95wt% oxides of rare earth elements (for example, La2O3). The catalyst obtained by said method is high in slectivity and high in activity at low temp. for the reaction wherein methanol or the mixture of methanol and water serving as raw material is reformed to a gas contg. methane thereby and has performance remarkably excellent in durability.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a catalyst for producing methane-containing gas.

For details, refer to the method for reforming methanol or a mixture of methanol and water into a methane-containing gas as a raw material.
It provides a highly active and long-life catalyst that selectively generates methane at low temperatures.

Conventionally, high calorific value gas containing methane has been obtained by catalytically cracking hydrocarbons such as naphtha and butane using a Ni-based catalyst. However, this conventional method has the following drawbacks.

(1) Since it is necessary to desulfurize the raw material prior to catalytic cracking, it is necessary to install a desulfurization equipment and manage its operation, resulting in high losses.

(il) Since the Ni precatalyst does not exhibit catalytic activity in a low temperature range, it is necessary to carry out the catalytic reaction at a high temperature, which is disadvantageous for increasing the calorific value of the produced gas.

(110) Due to the high temperature gasification, preheating of the raw material by an external heat source is necessary, which causes a decrease in the thermal efficiency of the entire process.

In addition, recent efforts have been made to introduce liquefied natural gas, but liquefied natural gas has technical limitations in terms of storage and transportation, and there are problems in that it requires a huge amount of investment.

Due to the above situation, all countries that produce natural gas or coal first decompose it into synthesis gas consisting of hydrogen and carbon oxide using steam, then convert it to methanol on a catalyst, and transport and consume this methanol. Methods such as using it directly as fuel in the ground or converting methanol into methane and using it as a gas fuel are being considered.

Conventionally, the following catalysts have been proposed as catalysts for converting methanol into methane-containing gas.

(11 Nickel catalyst with activated aluminum and/or diatomaceous earth as a carrier (4? 1973-1221023 (2)
A catalyst containing 25 to 50% by weight of nickel, aluminum, at least 5% by weight of molten cement, and at least 5% of zirconium dioxide or titanium dioxide (JP-A-53-55702.54-111505) However, these catalysts Until now, many problems remain, such as poor low-temperature activity, lack of heat resistance, and low methane content in the produced gas.

Among the conventional catalysts mentioned above, for example, the catalyst in which nickel is supported on r-mut303 causes not only the desired reaction (1) but also a side reaction (2) in which hydrogen, -carbon oxide, ether, aldehyde, carbon, etc. are produced. The problem is that it is easy.

Reaction ■ 40H30H-+50H4+ 2H30+ 002 Reaction ■ OH, OH→Co + 2H.

OH, OH + HIO200g + 5H10H, OH
→ 1/20H100H1+1/2H,00HIOH-
+ HOHO+ Hl OH,OH→0 + 112 + HIO200→O+
, 001 Among the above reactions, (1) is the reaction with the highest yield of methane per mole of raw methanol, and since water or carbon dioxide gas can be easily removed, a gas with the highest calorific value can be obtained.

In addition, the carbon production reaction of reaction (2) causes deterioration of the catalyst or blockage of the reactor, which impedes long-term stable operation.

Therefore, in order to solve the above problem, the present inventors discovered that side reactions such as ether formation are suppressed by the basicity of the carrier containing the oxide of a rare earth element, and that the nickel or nickel supported on the carrier is We focused on the fact that nickel oxides are highly stabilized without causing spinel compound formation reactions with the support, and after conducting various experiments, we found that nickel or We have discovered that a catalyst supporting nickel oxide has extremely excellent activity and selectivity in the reaction of producing a methane-containing gas from methanol or a mixture of methanol and water.
The present invention has now been completed.

That is, the gist of the present invention is a catalyst for producing methane-containing gas using methanol or a mixture of methanol and water as a raw material, the catalyst having nickel or a nickel oxide supported on a carrier containing an oxide of a rare earth element. It is something to do.

Here, the carrier containing an oxide of a rare earth element is defined as a carrier containing an oxide of a rare earth element at least α01% by weight or more (hereinafter referred to as
Preferably, the carrier contains 1 to 95% by weight of oxides of rare earth elements, and alumina, titania, zirconia, silica, and other binders are used as substances other than oxides of alkaline earth metal elements. Refers to something that contains all ingredients.

The above carrier can be prepared by coating with an oxide of all rare earth elements such as alumina or titania, which is commonly used as a support, or by physically mixing all rare earth element oxides with alumina, titania, etc. An applicable method includes adding alkali Vt to a mixed solution of an aqueous solution containing a compound of aluminum and an aqueous solution containing an aluminum compound to form a precipitate IR.

Here, the oxide of a rare earth element is an oxide of a rare earth element in group T of the periodic table, such as lanthanum oxide (La
3), cerium oxide (CoOx), neodymium oxide (”
d'i'os), or a mixture of these.

An example of a carrier containing an oxide of a rare earth element is L
a10g -At20g, La1O1-Ti02
, 0e01-A40s aOeOl-Ti0g , O
eO, -810*, Nd*0s-A4Os e N
&0n-TiOzsN (11%-ZrOl, Nd2
There are combinations such as 0g-0eO1-Az and ol.

To explain the preparation method using La103-AtlOs carrier as an example, (1) immersing alumina in a lanthanum nitrate water bath solution (2)
) Immerse alumina in a lanthanum nitrate aqueous solution and add alkali gold such as soda carbonate to create a precipitate (31 ha, mix with total alumina sol such as os (4
) It can be easily obtained by adding an alkaline solution such as soda carbonate to a mixture of a lanthanum compound-containing water bath solution and an aluminum compound-containing water bath solution to form a precipitate.After any of the above steps, it is dried and fired.

Next, the method of supporting nickel or nickel oxide on the carrier thus obtained can be any conventional method without any problems, such as nickel nitrate, sulfate,
By immersing the carrier in a water bath containing compounds such as chlorides, acetates, and formates, and then drying and firing, a catalyst that supports nickel oxide can be obtained.If this is further reduced by hydrogen treatment, nickel can be supported. A catalyst is obtained. here,
The supported amount of nickel or nickel oxide (hereinafter, supported amount is expressed as N based on the total weight of the catalyst) is at least α011 amount or more, preferably in the range of 1 to 90% by weight.

The catalyst obtained as described above has high selectivity and activity in the reaction of reforming methanol or a mixture of methanol and water into a methane-containing gas as a raw material, and has extremely excellent durability. It is something that you have.

Hereinafter, the present invention will be specifically explained with reference to Examples.

[Example 1] Pellets consisting of rm4os with a particle size of 2 to 4111II were immersed in an aqueous solution of cerium nitrate, dried, and heated at 500°C for 30 minutes.
After firing for a period of time, a carrier was obtained in which 10% by weight of 0eO1 was supported on alumina.

The carrier thus obtained was immersed in an aqueous solution of nickel nitrate, dried, and then calcined at 500°C for 3 hours to give a weight of 10%
Catalyst 1 (based on the total weight of the catalyst) supported on nickel oxide was prepared.

This catalyst was reduced at 400° C. for 5 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 catalyst was prepared in which 10wt 1% (based on the total weight of the catalyst) of nickel oxide was supported on a conventional r-mu-teas carrier, and all activity evaluation tests were conducted at a reaction temperature of 400°C.The results are shown in Table 2. Indicated.

Table 1 Table 2 Below, the cracked gas composition is expressed on a dry gas basis excluding water and gold.

[Example 2] OeO in the same manner as Catalyst 1 prepared in Example 1.

The concentrations (based on the total amount of carrier) are 1.5.20° and 50.0°, respectively.
A carrier having a weight of 90% by weight is prepared, immersed in an aqueous solution of nickel nitrate, and fired to reduce the amount of nickel oxide to 10% by weight. Two to six catalysts were prepared, each of which was supported so as to have the same weight (based on the total weight of the catalyst).

These catalysts were subjected to an activity evaluation test after hydrogen reduction treatment under the conditions shown in Table 1 except that the reaction temperature was 1400° C., and the results shown in Table 3 were obtained.

Cloth 3 [Example 3] A pellet made of r-Altos with a particle size of 2 to 4 wm was immersed in a mixed water bath solution of nitrates of lanthanum, cerium, neodymium, and praseodymium, and then dried and fired to form a mixed oxide of rare earth elements in alumina. (ha, os22 wt%e'
eOs 48 wt%a IJamos17wt%,
A carrier was obtained in which 20% by weight (based on the total weight of the carrier) of prsoll (15 wt%) was supported. Example 1
Using the same method as above, the concentration of nickel oxide was 5.20°50. 80
Catalyst 7 supported so as to be % by weight (based on the total weight of the catalyst)
10 was prepared.

In addition, catalyst 11.12 was prepared by completely immersing the above-mentioned carrier in each aqueous solution of nickel chloride and nickel acetate, drying it, and calcining it at 500°C for 3 hours so that the amount of nickel oxide supported was 10% by weight (based on the total weight of the catalyst). Prepared.

The above carrier was immersed in an aqueous solution of nickel nitrate, and an alkali (
Aqueous ammonia and aqueous sodium carbonate solution were added as precipitants, respectively, to form a precipitate of nickel hydroxide on the surface of the carrier, followed by drying and calcination to produce a catalyst that supported 10% by weight (based on the total weight of the catalyst) of nickel oxide. No. 13 (using aqueous ammonia) and No. 1'4 (using aqueous sodium carbonate solution) were all prepared.

These catalysts were subjected to an activity evaluation test under the conditions shown in Table 4 after hydrogen reduction treatment, and the results shown in Table 5 were obtained.

Table 4 Table 5 [Example 4] Titania,
A carrier 1.2 was obtained in which 10 weight of OeO1 was supported on each zirconia (based on the total weight of the carrier). 20 weight T for each carrier
Catalyst 1 carrying o (based on total catalyst weight) of nickel oxide
5.16'i lyrics were written.

Table 6 prepared by precipitation method using nitrate aqueous solution as starting material
Catalyst 1"7-20', in which 20% by weight (based on the total weight of the catalyst) of nickel oxide was supported, was obtained by immersing carrier 3 with the composition shown in 6' in an aqueous solution of nickel nitrate, drying and calcining it.
i prepared.

For these catalysts, after hydrogen reduction treatment, an activity evaluation test was conducted under the conditions shown in Table 4, and the results were shown in Table 60. The tube was filled, and methanol was continuously supplied at 20 aφ at 400° C., and a durability test was conducted for 3000 hours.

As a result, as shown in Table 7, there was a lot of carbon deposited on the comparative catalyst wire, and the deterioration was severe, but catalyst 1 of the present invention showed almost no change from the initial stage in both methanol reaction rate and cracked gas composition, and there was no carbon deposit on the catalyst surface. It was confirmed that there was no precipitation.

Table 7 The amount of carbon deposited on the catalyst after 5000 hours was as follows.

In the case of catalyst 1: 12% by weight In the case of comparative catalyst: 9% by weight Although granular catalysts are described in the examples, the shape of the catalyst is not particularly limited, and it goes without saying that shapes such as honeycomb shapes may be used. .

Among the sub-agents: 1) Akira Sub-agent Ryo Hagi Hara -

Claims (1)

[Claims] A catalyst for producing a methane-containing gas using methanol or a mixture of methanol and water as a raw material, characterized in that nickel or a nickel oxide is supported on a carrier containing an oxide of a rare earth element.