METHOD FOR NON-OXIDATIVE DIRECT CONVERSION OF METHANE

Abstract

The present disclosure relates to a method for non-oxidative direct conversion of methane. Specifically, in the method, a methane/hydrogen gas is introduced into an Inconel 600 reactor at a superficial velocity of 100 to 200 cm.Math.min.sup.−1 and a catalyst is not externally introduced into the reactor. Under the conditions, a non-oxidative direct methane conversion reaction is performed in the Inconel 600 reactor. The method maximizes the reaction rate, minimizes coke formation, and increases the yields of C.sub.2 hydrocarbon compounds and aromatic compounds.

Claims

1. A method for non-oxidative direct conversion of methane, the method comprising: (a) supplying a methane feed gas comprising methane at a superficial velocity in a range of 100 cm.Math.min.sup.−1 to 200 cm.Math.min.sup.−1 to a reactor having an inner surface of made of Inconel 600; and (b) obtaining a compound having two or more carbon atoms, produced in the reactor having the inner surface made of Inconel 600.

2. The method of claim 1, wherein the methane feed gas is supplied at a weight hourly space velocity in a range of 8 min-1 to 10.5 min-1.

3. The method of claim 1, wherein the methane feed gas is supplied at a flow rate in a range of 80 cm.sup.3 min.sup.−1 to 300 cm.sup.3.Math.min.sup.−1.

4. The method of claim 1, wherein the methane is comprised in the methane feed gas in an volume ratio 20% to 100% with respect to the volume of the methane feed gas.

5. The method of claim 1, wherein the methane feed gas comprises methane gas and hydrogen gas.

6. The method of claim 1, wherein a reaction was performed at a reaction temperature is in a range of 1000° C. to 1250° C.

7. The method of claim 1, wherein a ratio of amorphous carbon to crystalline carbon in a carbon layer formed in the Inconel 600 reactor is in a range of 1:4 to 2:3

8. A non-oxidative direct methane conversion catalyst being a composite catalyst comprising Inconel 600 alloy coated with a carbon layer, wherein a ratio of amorphous carbon to crystalline carbon of carbon components is in a range of 1:4 to 2:3.

9. A method for non-oxidative direct conversion of methane, the method comprising: supplying a methane feed gas comprising methane gas and hydrogen gas to an Inconel 600 reactor having the catalyst of claim 8 on an inner surface thereof; and obtaining a compound having two or more carbon atoms, produced in the Inconel 600 reactor.

10. The method of claim 9, wherein the methane feed gas is supplied at a superficial velocity in a range of 100 cm.Math.min.sup.−1 to 200 cm.Math.min.sup.−1.

11. The method of claim 9, wherein the methane feed gas is supplied at a weight hourly space velocity in a range of 8 min.sup.−1 to 10.5 min.sup.−1.

Description

[Experimental Example 4] Measurement of Concentration of Each Component in Inner Surface Layer of Inconel 600 Reactor

[0057] FIG. 4 illustrates scanning electron microscope (JEOL, JS-6010) images of the inner surface layer of the Inconel 600 reactor for each of Example 1 and Comparative Example 1 of the present disclosure, and the results of energy disperse X-ray spectroscopy (EDS) for the inner same surface layers.

[0058] As illustrated in (a) of FIG. 4, in the case where the methane feed gas is introduced into the Inconel 600 reactor at a relatively low superficial velocity, carbon atoms are uniformly dispersed in the reactor surface layer. However, when the methane feed gas is introduced into the Inconel 600 reactor at a relatively high superficial velocity, a metal film is formed on the inner surface of the reactor, and iron that promotes the formation of coke is precipitated, contributing to lowering the methane conversion rate.

[0059] In FIG. 4, the graph indicates the results of Raman spectroscopy to measure the content of crystalline carbon in the inner surface layer of the Inconel 600 reactor after the reaction. In the case of Example 1 in which direct conversion of methane was performed at a relatively low superficial velocity, the ratio of crystalline carbon to amorphous carbon was 3.44, whereas in the case of Comparative Example 1 in which the reaction was performed at a relatively high superficial velocity, the ratio of crystalline carbon to amorphous carbon was 58.11. The results reveal that the uniform dispersion of a specific type of carbon is an important factor in non-oxidative conversion of methane into a yield of hydrocarbons.

[0060] All simple modifications or alterations of the embodiments may be readily practiced by those skilled in the art, and thus all such modifications or alterations will fall within the scope of the present disclosure.