JPH10139693A - Production of acetylene - Google Patents

Abstract

PROBLEM TO BE SOLVED: To enable conversion of methane to acetylene in high methane conversion and high acetylene selectivity by carrying out a microwave plasma reaction under specific conditions. SOLUTION: A methane-containing gas is introduced into a reaction tube such as a quartz tube optionally by using an inert gas such as Ar or N2 as a carrier gas. The reaction tube is irradiated with a microwave generated by a microwave oscillator of 2.45GHz in 5-10W/cc microwave density. Preferably, the linear velocity of methane introduced to the reaction tube is 5-15cm/minute, the reaction pressure is 2-10KPa and the reaction time is 0.1-10 seconds (irradiation time). The conversion of methane can be raised and the acetylene selectivity made >=85% by the reaction conditions.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

[0001] The present invention relates to a method for producing acetylene from a methane-containing gas.

[0002]

2. Description of the Related Art Various methods for synthesizing lower hydrocarbons other than methane from a gas such as methane or methane-containing natural gas have been proposed. For example, a method using a microwave plasma reaction has been proposed. The main purpose of this study is to study the production of

[0003]

However, when acetylene is intended, it is difficult to increase the selectivity of acetylene by the conventional method, although the conversion of methane can be improved. Therefore, the present inventors have conducted various studies to find a method that can improve the selectivity of acetylene, and have surprisingly found that this problem can be achieved by performing a microwave plasma reaction under specific conditions. ,
The present invention has been reached. That is, the present invention provides a density of 3 to 15
In the presence of a microwave of w / cc, a gas containing methane is introduced at a linear velocity of 2 to 20 cm / mim to cause a microwave plasma reaction to convert the methane to acetylene, thereby obtaining acetylene. The method of producing acetylene is summarized as follows.

[0004]

BEST MODE FOR CARRYING OUT THE INVENTION Hereinafter, the present invention will be described in detail.
First, in the present invention, examples of the gas containing methane as a starting material include methane gas, natural gas, and the like.
The methane content is not particularly limited. When the methane-containing gas is subjected to the microwave plasma reaction, an inert gas such as Ar or N ₂ may be used as the carrier gas.

[0005] A reactor for performing a microwave plasma reaction includes a gas supply unit, a microwave generation unit, and a reaction unit.
When the above-mentioned carrier gas is used, the reaction tube that introduces the supply gas adjusted to a predetermined component ratio by the gas mixer into a reaction section composed of a reaction tube that does not absorb microwaves, such as a quartz glass tube, is a vertical type. This is preferable from the viewpoint of observing the behavior in the tube at the time of plasma generation.

[0006] The reaction unit, the microwave generation part, for example, it is preferable to be plasma reaction by irradiation through 2.45 GHz _Z horizontally installed waveguides the microwave generated by the microwave oscillator . In the present invention,
When performing this plasma reaction, it is necessary to first set the density of the microwave to 3 to 15 w / cc, preferably 5 to 10 w / cc. If it is less than 3 w / cc, the conversion of methane and the selectivity of acetylene decrease. on the other hand,
If it exceeds 15 w / cc, an oily substance (C ₆ -C ₂₀ compound)
Adheres to the tube wall, making continuous reaction difficult, and the selectivity of acetylene decreases.

In the present invention, the linear velocity of the methane to be introduced is preferably 2 to 20 cm / mim, more preferably 5 to 1 cm.
5 cm / mim. If it is less than 5 cm / mim, an oil is likely to be generated, and if it exceeds 15 cm / mim, the conversion of methane and the selectivity of acetylene decrease. In supplying the raw material gas, the reaction pressure is usually 2 to 10
It is selected from about kPa. The reaction time is 0.1 to
Generally, it is selected from about 10 seconds (irradiation time).
ADVANTAGE OF THE INVENTION According to this invention, the conversion rate of methane can be made high, and the selectivity of acetylene can be set to 85% or more, preferably 95% or more.

[0008]

The present invention will be described below in detail with reference to examples. Example 1 A methane (purity: 99.2%) microwave plasma reactor was introduced at a linear velocity of 5 cm / mim. The reaction tube is a vertical type made of silica glass was irradiated to the reaction tube through the 2.45 GHz _Z microwave waveguide installed horizontally to generate a.
The microwave density is as shown in Table 1. The reaction pressure was 7.5 kPa. The reaction product was analyzed by gas chromatography using a sampler for reduced pressure. The yield of the reaction product was as follows.

[0009]

[Table 1] The generation of C ₃ and C ₄ compounds was very small. * A large amount of oil adhered to the reaction tube wall.

Claims (1)

[Claims] In the presence of a microwave having a density of 3 to 15 w / cc, a gas containing methane is subjected to a linear velocity of 2 to 20 cm /
A method for producing acetylene, characterized in that acetylene is obtained by converting the methane to acetylene by microwave reaction with introduction by mim.