JPH0278636A - Production of c2 hydrocarbon and device therefor - Google Patents

Abstract

PURPOSE:To obtain the title compound in high selectivity by circulating methane to one of divided zones separated by a porous material coated with magnesia carrying lead oxide and an oxygen gas to the other and carrying out oxidation coupling reaction. CONSTITUTION:A porous material (e.g., alumina or silica) having 5-5,000nm, preferably 10-1,000nm average pore diameter is coated with a saturated aqueous solution of magnesium nitrate in a concentration hardly to leak a reaction gas, calcined with air at 600 deg.C to form a coating film 11 of magnesium oxide, an aqueous solution of lead nitrate is applied to the coating film and the coated material is similarly sintered to form a lead oxide coating 12 to give a substrate 1 coated with the catalyst. The substrate 1 is inserted into a quartz tube 2, methane is circulated from a methane inlet 4 to a methane feed zone 8, an oxygen gas is sent from an oxygen inlet 5 to an inner side 9 of the substrate 1 and oxidation coupling reaction of methane is carried out at 600-900 deg.C with oxygen anion of lead oxide lattice permeated from the oxygen side through the catalyst to the methane side to give C2 hydrocarbon.

Description

Detailed Description of the Invention [Field of Industrial Application] The present invention relates to a method and apparatus for producing Cz hydrocarbons by an oxidative coupling reaction of methane.4 [Prior Art] Conventionally, by an oxidative coupling reaction of methane, Various methods have been proposed for directly producing C2 compounds, such as ethane and ethylene, from methane.

JP-A-61-30688 discloses that by applying a voltage to a solid electrolyte and allowing oxygen to permeate, the oxygen and lower hydrocarbons such as methane are converted into hydrocarbons having a carbon number greater than that number, such as ethane and ethylene. A method for producing 02 hydrocarbons from methane is disclosed, but the selectivity to 02 hydrocarbons from methane is 9
It is only less than 0%. Furthermore, oxygen gas is present on the methane side.

JP-A No. 62-61933 discloses that hydrocarbons having two or more carbon atoms are synthesized by an oxidative coupling reaction of methane with molecular oxygen in the presence of a lead oxide catalyst supported on a basic carrier such as magnesium oxide. A method is disclosed. However, the selectivity for C2 hydrocarbons is about 85%
It is nothing more than the following.

Chem, LeLt, 3 1 9 ~ 3 2
2 (1985) reports on the oxidative coupling reaction of methane using stabilized zirconia, but the selectivity to C2 hydrocarbons is substantially only about 50% or less.

[Problem to be solved by the invention]

In the past, many attempts have been made to produce 02 hydrocarbons such as ethane and ethylene directly from methane, but the selectivity of C2 hydrocarbons in the conventional methods is low and is not yet satisfactory.

Moreover, it is necessary to use expensive pure oxygen as an oxidizing agent.

When air, which is an inexpensive oxidizing agent, is used, a large amount of nitrogen is mixed into the produced gas, and a large amount of cost is required to separate it from the unreacted raw material methane or produced hydrocarbons.

The present invention is a method for producing 02 hydrocarbons directly from methane with an extremely high selectivity of virtually 100%, using an inexpensive oxidizing agent such as air, and without mixing nitrogen gas or oxygen gas. The object of the present invention is to provide a device for the same.

[Means to solve the problem]

Firstly, when methane or a methane-containing gas is passed through one side of the support made of a porous body and oxygen gas or an oxygen-containing gas is passed through the other side, both gases are passed through the porous body. While the porous body is coated with a magnesia-supported lead oxide catalyst until no longer mutually permeable,
A method for producing C2 hydrocarbons, which is characterized by carrying out an oxidative camping reaction of methane by means of lead oxide lattice oxygen anions supplied to the methane side through the catalyst from the oxygen side while respectively circulating the two gases. It provides:

Second, the present invention provides an apparatus for producing C2 hydrocarbons by an oxidative coupling reaction of methane, which comprises an oxygen or oxygen-containing gas supply region, a methane or methane-containing gas supply region, and a support made of a porous material. , and a magnesia-supported lead oxide catalyst, the porous body is coated with the catalyst until both gases no longer permeate each other, and the both gas supply regions are separated via the catalyst-coated porous body. The present invention provides an apparatus for producing C2 hydrocarbons as described above.

The porous material constituting the support used in the present invention is, for example, a porous material such as alumina, silica, magnesia, etc., and has an average pore diameter of 5 to 5000 nm, preferably 10 to 11
If the thickness is less than 5 nm, oxygen gas will not reach the catalyst membrane sufficiently, which is undesirable, and if it exceeds 5,000 nm, it will be difficult to stably support the catalyst membrane, which is undesirable.

The film thickness of the porous body is O, 1 to 50, preferably 1 to I.
On, if it is less than 0.1 tm, the strength of the porous body is insufficient, which is not preferable, and if it exceeds 50 mm, the passage speed of oxygen-containing gas is slow, which is not preferable.

The support used in the present invention is, for example, a tube made of the porous material described above, and, for example, an oxygen or oxygen-containing gas supply area may be provided on the inside thereof, and a methane or methane-containing gas supply area may be provided on the outside thereof. You can do it, but it can also be the other way around.

The porous body constituting the support used in the present invention is coated with a magnesia-supported lead oxide catalyst until the gas used no longer permeates through each other, and both gas supply regions are mutually connected via the catalyst-coated porous body. separated into

In the oxidative coupling reaction of methane in the present invention, the molar ratio of methane and oxygen usually supplied is in the range of 100/1 to 1/2, but the methane-containing gas and the oxygen-containing gas are supplied to separate reaction zones. Therefore, there is no limit to the molar ratio of supply. Differential pressure between methane supply area and oxygen supply area is 0 to 5
Atmospheric pressure preferably in the range of 0 to 1 atm 600 to 90
It is carried out at 0°C, preferably 700-800°C.

If the molar ratio is less than 100/1, the methane conversion rate will be low, which is not preferable, and if it exceeds 1/2, the oxygen utilization efficiency will be low, which is not preferable. If the pressure difference exceeds 5 atmospheres, the catalyst membrane may be destroyed, which is not preferable. The reaction temperature is 600
If it is less than 900°C, the reaction rate will be low, which is undesirable, and if it exceeds 900°C, thermal decomposition of methane will proceed, resulting in a decrease in C2 hydrocarbon production activity and selectivity, which is not preferred.

In the methane oxidative coupling reaction of the present invention, the supplied oxygen gas, that is, molecular oxygen, is separated from methane or methane-containing gas through the catalyst-coated porous body, so it directly reacts with carbon dioxide gas. It permeates through the catalyst coating in the form of lattice oxygen without causing any oxidation, and the reaction takes place in the form of permeated oxygen in contact with methane.

〔Effect of the invention〕

According to the present invention, a method and apparatus for producing C2 hydrocarbons directly from methane with a selectivity of substantially 100% are provided.

According to the present invention, even when air is used as the oxygen-containing gas, C2 hydrocarbons can be directly extracted from methane to substantially 1% without requiring a process to separate nitrogen and oxygen from the production system.
A method and an apparatus thereof are provided that allow production with a selectivity of 0.00%.

〔Example〕

Example 1 For one example of the method and apparatus of the present invention,
This will be explained below using figures. FIG. 1a is a schematic sectional view of a fixed bed normal pressure flow type apparatus of the present invention for explaining the present invention, and FIG. 1b is an enlarged view of part 7 in FIG.
Figure C is an enlarged imaginary view of portion IO of Figure 1b.

The support l has a length of about 30 cm, an outer diameter of 4 mm, and an inner diameter of 1 mm.
5N, alumina porous material CTD with an average pore diameter of 500 nm
A tube of DYNACERAM (manufactured by K. K.) was used. The part of the support 1 where the reaction temperature is applied (5c
After coating the parts other than the parts (approximately 1.5 m) with a high-temperature sealing material (Aron Ceramic manufactured by Toagosei Chemical Co., Ltd.), a saturated aqueous solution of magnesium nitrate was applied at a concentration that would prevent the reaction gas from leaking, and air baking was performed at 600°C. Check the leakage and the weight of the catalyst carrier, and if there is no leakage, then
If necessary, the operation was repeated one more time to form the magnesium oxide coating 11. After that, an aqueous solution of about 20% lead nitrate, which easily forms a uniform film as lead oxide, is applied thereon, and the same firing, checking and repeating operations are performed to form the lead oxide coating 12, and the catalyst is applied. Support 1 was obtained. The support I coated with this catalyst has an outer diameter of 8
The device of the present invention was prepared by inserting the dragon into the inside of a quartz tube 2 having an inner diameter of 61 m. In this device, for example, methane is passed from the methane population 4 to the outside of the support 1, that is, the methane supply zone 8, while oxygen gas is passed from the methane population 5 to the inside of the support 1, that is, the oxygen supply zone 9, and heated. The reaction was carried out while heating to the reaction temperature in the furnace 3, and the produced gas from the produced gas outlet 6 was subjected to analysis. In FIG. 1c, numeral 13 indicates the pores of the porous body constituting the support 1. In FIG.

Analysis was performed on the methane side, and analysis on the oxygen-containing gas side was limited to monitoring mass balance and leakage. The pressure difference between the inside and outside of the support 1 is measured by installing a water column differential pressure gauge at the rear of the reaction zone, and is kept within a maximum of 20 weight H,o.

The passage of the reaction gas through the porous body, that is, the leakage, was carried out three times by flowing an oxygen-containing gas inside the support 1 and an inert gas (nitrogen, helium, etc.) outside, and monitoring the nitrogen and oxygen outside. .

Example 2 The following experiment was conducted to demonstrate that the oxidative coupling reaction of methane in the present invention is due to lattice oxygen.

Using the apparatus of Example 1, the reaction temperature was 750°C, the methane side flow was 1100 cc/min (methane content 99% or more), and the oxygen side 2+ was heated at 30 cc for 7 minutes (M basic gas about 20%, remaining nitrogen). A pulse introduction operation was performed in which the oxygen-containing gas inside the support 1 was replaced with nitrogen while flowing methane outside the support 1. The results are shown in FIG. As shown in Figure 2, C in response to oxygen on/off
The generation of 2 hydrocarbons was observed, and 02
No hydrocarbons were produced. Therefore, it was demonstrated that the oxygen used in the reaction was supplied from an oxygen-containing gas and was used in the reaction with oxygen ions in lead oxide.

Example 3 Using the apparatus of Example 1, an oxidative coupling reaction of methane was carried out by changing the reaction temperature. The results obtained are shown in Table 1. As shown in Table 1, the product is only C2 hydrocarbons and no carbon dioxide gas is produced, indicating that C2 hydrocarbons can be obtained directly from methane with a selectivity of substantially 100%. The methane conversion rate is low because the methane contact time is approximately 0.
．． This is thought to be because the reaction time was as short as 2 seconds and because the rate-determining process in the reaction was the expansion of oxygen into the catalyst, and as a result, the catalyst surface on the methane side was reduced to metallic lead. It is observed that the methane conversion rate and the amount of C2 hydrocarbon production tend to increase at higher temperatures.

Table 1 Catalyst amount: 0.15g (reaction part), flow rate: 100cc/
Example 4 based on min moles Using the apparatus of Example 1, an experiment was conducted by varying the flow rate on the methane side. The results obtained are shown in Table 2.

Example 5 Using the apparatus of Example 1, an experiment was conducted by changing the reaction temperature. The results obtained are shown in Table 3.

Example 6 Using the apparatus of Example 1, an experiment was conducted while varying the oxygen concentration on the oxygen side. The results obtained are shown in FIG.

[Brief explanation of the drawing]

FIG. 1a is a schematic cross-sectional view of the device for explaining the present invention, FIG. 1b is an enlarged view of section 7 in FIG. 1a, and FIG. 1C is an imaginary enlarged view of section 10 in FIG. 1b. be. Second
The figure is a graph showing the relationship between the reaction time and the yield (%) of 02 hydrocarbons when the supply of oxygen gas is turned on and off. FIG. 3 is a graph showing the relationship between oxygen concentration and yield of 02 hydrocarbons.

Claims (1)

[Claims] 1. When methane or a methane-containing gas is passed through a support made of a porous material to one side and oxygen gas or an oxygen-containing gas is made to flow to the other side, through the porous material, The porous body is coated with a magnesia-supported lead oxide catalyst until both gases no longer permeate each other, and while both gases are allowed to flow, oxidation is supplied from the oxygen side through the catalyst to the methane side. A method for producing C_2 hydrocarbons, characterized by carrying out an oxidative coupling reaction of methane with lead lattice oxygen anions. 2. The method for producing C_2 hydrocarbons according to claim 1, wherein the porous body has an average pore diameter of 5 to 5000 nm and a film thickness of 0.1 to 10 mm. 3. The method for producing C_2 hydrocarbons according to claim 1, wherein the support is a porous tube, and either one of the two gases is allowed to flow through either the inside or the outside of the tube. 4. The oxidative coupling reaction of methane is 600-900
The method for producing C_2 hydrocarbons according to claim 1, which is carried out at a temperature of °C. 5. An apparatus for producing C_2 hydrocarbons by oxidative coupling reaction of methane, comprising an oxygen or oxygen-containing gas supply region, a methane or methane-containing gas supply region, a support made of a porous material, and magnesia supported oxidation. The porous body is made of a lead catalyst, and the porous body is coated with the catalyst until both gases no longer permeate each other, and the gas supply areas are separated via the catalyst-coated porous body. An apparatus for producing the above C_2 hydrocarbon. 6. The C_2 hydrocarbon production apparatus according to claim 5, wherein the porous body has an average pore diameter of 5 to 5000 nm and a film thickness of 0.1 to 10 mm. 7. The C_2 hydrocarbon production apparatus according to claim 5, wherein the support is a porous tube, and either one of the two gases is allowed to flow through either the inside or the outside of the tube.