JPS6235814B2 - - Google Patents

Description

[Detailed description of the invention]

The present invention relates to a methanol reforming catalyst. More specifically, as a catalyst for reforming methanol into a gas mainly composed of hydrogen, carbon monoxide, and methane, crystalline aluminosilicate zeolite is combined with a group of base metal elements consisting of chromium, manganese, iron, cobalt, nickel, copper, and zinc. Catalysts characterized by supporting one or more metals or their oxides, or one or more metals from the group of platinum group elements consisting of rhodium and ruthenium, increasing activity at low temperatures and having a long life. Regarding. Currently, petroleum and products refined and separated from petroleum are used as raw materials for the production of liquid and gaseous fuels and reducing gas used in power generation boilers and internal combustion engines, but with the recent rise in oil prices and the diversification of fuels. Given the current situation, methanol, which is synthesized from fossil fuels other than petroleum, is attracting attention. Furthermore, since methanol is decomposed and reformed into hydrogen and carbon monoxide at a lower temperature than gasoline, it has the advantage of using waste heat as a heat source. At this time, the generated reformed gas has the advantage that the calorific value of the reformed gas increases by the amount equivalent to the endothermic amount of the decomposition reforming reaction (approximately 22 Kcal/mol), and furthermore, the generated reformed gas has a high octane value. When applied to internal combustion engines, it has the advantages of increasing the compression ratio, improving thermal efficiency, and enabling clean combustion. Due to the advantages of methanol fuel as mentioned above, research has been conducted on catalysts for reforming methanol for some time.
Catalysts have been proposed in which oxides of base metal elements such as copper and zinc are supported on carriers such as alumina, but these catalysts still have many problems such as performance and lifespan. In producing a gas mainly composed of hydrogen, carbon monoxide, and methane through a methanol reforming catalytic reaction, the present inventors added platinum group elements such as rhodium and ruthenium or chromium to crystalline aluminosilicate zeolite. manganese, iron, cobalt,
Focusing on the fact that catalysts supporting base metal elements such as nickel, copper, and zinc and their oxides are highly active at relatively low temperatures, extensive experimental studies were conducted to develop catalysts that are highly active and selective at low temperatures. We have now provided the following. The present invention is characterized by the use of crystalline aluminosilicate zeolite, which has uniform pore diameters in the range of 3 to 15 Å, unlike alumina, which has traditionally been known as a carrier and has large pore diameters and a wide distribution. The alkali metal or alkaline earth metal in this crystalline aluminosilicate zeolite is converted into a platinum group element or base metal element by ion exchange, or the surface of the crystalline aluminosilicate zeolite is treated with a platinum group element or a base metal element and its oxide. As a result of impregnating and supporting the catalyst by heat treatment, it was found that it has extremely high activity even at a considerably lower temperature than conventional catalysts. Here, the crystalline aluminosilicate zeolite is an aluminosilicate consisting of a compound of SiO ₂ , Al ₂ O ₃ , and an alkali or alkaline earth metal, and may be a synthetic product or a naturally occurring product, such as a commercially available synthetic zeolite. F9 (manufactured by Toyo Soda, chemical formula
Na ₂ O・Al ₂ O ₃・2.5SiO ₂ ) Naturally occurring materials include mordenite. Further, the SiO ₂ /Al ₂ O ₃ ratio may also be 12 or less. In addition, there are two methods for supporting platinum group elements or base metal elements and their compounds on crystalline aluminosilicate zeolite: an ion exchange support method and an impregnation support method. Can be prepared. For example, for the former ion exchange loading method, 1 mol/l
Crystalline aluminosilicate zeolite is immersed in an aqueous metal chloride solution, and heated at around 80 to 100℃ for 10 to
There are two methods of impregnating and supporting a base metal element oxide: immersing the support in a nitrate aqueous solution of a base metal element and then baking it; When supported, there are methods such as immersing the support in an aqueous solution of chloride of a platinum group element and then reducing it with hydrogen, and the catalyst of the present invention can be prepared using any of these methods. The catalyst obtained as described above exhibited high catalytic activity in the temperature range of 300 to 800° C. for the reforming reaction of methanol with a gas mainly composed of hydrogen, carbon monoxide, and methane. Further, the methanol reforming reaction may be performed using methanol alone or in the coexistence of methanol and a gas containing steam, carbon dioxide gas, or oxygen. In addition, in the embodiments of the present invention, platinum group elements include rhodium and ruthenium, and base metal elements include chromium,
Although only examples of manganese, iron, cobalt, nickel, copper, and zinc are shown, other platinum group elements and base metal elements may be used, or two or more elements may be used in combination. Hereinafter, the present invention will be specifically explained with reference to Examples. [Example 1] 100 g of synthetic zeolite F9 (manufactured by Toyo Soda) with a particle size of 2 to 4 mm was immersed in 500 ml of an aqueous chloride solution (1 mol/) of rhodium, ruthenium, chromium, manganese, iron, cobalt, nickel, copper, or zinc. After ion exchange treatment at 80℃ for 20 hours and washing with water,
Catalysts 1, 2, 3, 4, 5, 6, 7, 8, and 9 were prepared by drying at 110°C for 12 hours and calcining at 400°C for 5 hours. The activity of these catalysts was evaluated under the conditions shown in Table 1, and the results are shown in Table 2.

【table】

[Example 2]

Synthetic zeolite F9 (manufactured by Toyo Soda) with a particle size of 2 to 4 mm was immersed in an aqueous solution of rhodium or ruthenium chloride.
Catalyst supported at 0.5% by weight
10, 11, also chromium, manganese, iron, cobalt,
Catalysts 12, 13, 14 each immersed in an aqueous nitrate solution of nickel, copper or zinc to support 5% by weight of chromium oxide, manganese oxide, iron oxide, nickel oxide, copper oxide or zinc oxide, respectively.
15, 16, 17, and 18 were prepared, respectively. The activity of these catalysts was evaluated under the same conditions as in Example 1, and the results are shown in Table 3.

[Example 3]

Catalyst 19 carrying 0.5 weight percent of rhodium and ruthenium each in the same manner as in Example 2,
Catalyst 20 was prepared in which copper oxide and chromium oxide were each supported at 5% by weight, and catalyst 21 was prepared in which zinc oxide and chromium oxide were each supported at 5% by weight. The activity of these catalysts was evaluated under the same conditions as in Example 1, and the results are shown in Table 4.

[Example 4]

The reaction temperature is the same as in Table 1 except for the reaction temperature, which is 400℃.
When a test was conducted on catalyst No. 16 of Example 2 by changing the temperature from
It was 94% at ℃ and 100% at 500-800℃. For a conventional catalyst in which 5 weight percent of nickel oxide is supported on an alumina carrier (particle size 2 to 4 mm), a temperature of 560°C is required to achieve a methanol reaction rate of 94%, and the catalyst of the present invention has a lower temperature than the conventional catalyst. This shows that it is highly active. As shown in the examples above, we have proposed the present invention, which is unique in that it has high catalytic activity at low temperatures and little carbon precipitation.

Claims (1)

[Claims] 1. Crystalline aluminosilicate zeolite containing one or more metals or oxides thereof from the group of base metal elements consisting of chromium, manganese, iron, cobalt, nickel, copper, and zinc, or a group of platinum group elements consisting of rhodium and ruthenium. A methanol reforming catalyst that supports one or more of the following metals.