Many components of the natural gas (methane, ethane, iso-butane, carbon oxides, nitrogen, hydrogen sulfide) in conjunction with water form gas hydrates. Hydrate formation favorably influenced by a combination of low temperature and high pressure. During gas production hydrates can be formed in the wellbores, industrial communications and natural gas pipelines. Sedimenting on the walls of pipes, hydrates sharply reduce their bandwidth. To struggle the hydrate formation the various inhibitors are used. One of the main inhibitors of hydrate formation is methanol as natural gas compound. Methanol consumption increases with increasing pressure and decreasing temperature. Therefore, the greatest consumption of methanol is required for the northern gas fields. On the northern gas fields the theoretical methanol consumption is up to 400 g of methanol per 1000 m3 of gas. Herewith the methanol concentration in the natural gas is about 0.03 vol. %.
Considering the large amount of produced gas, a lot of methanol is required. Methanol is delivered at the place of natural gas extraction. Many natural gas fields are located in remote places. Therefore methanol delivery at the place of gas production requires significant material and financial costs.
We offer to receive methanol from natural gas at the place of its production. As known, the main component of natural gas is methane. The oxidation of methane produces methanol. This process has not found industrial application since the methane is oxidized at high temperatures with the formation of final product – carbon oxides and water. High temperature is necessary for breaking the chemical bond between the carbon and hydrogen atoms to form free radicals.
All the others radical processes , the interaction of alkyl radicals with the oxygen molecule and alkoxy radicals with methane molecule as well as the decomposition of hydroperoxides occur at low temperatures. For the methanol production from methane the low temperature , pressure and a small concentration of oxygen in the reaction mixture are necessary. Reducing the temperature of oxidation can be reached with the radical initiators and molecules of methane in excited state. We found that under certain conditions, using a burner is possible not only heat the reaction mixture but also form the active center-radicals and excited molecules of methane.
We offer the following technological process of methanol obtaining from the natural gas: a part of the natural gas is heated on the special burner to a temperature of 250 – 400 °C with the formation of active centers. The heated gas is delivered into the tubular reactor where the oxygen-containing gas is supplied in a stepwise manner. The oxygen-containing gas is formed by mixing natural gas with air in a volume ratio 1 : 1. The amount of supplied gas is calculated so that the concentration of methanol in the reaction mixture will be about 3-7 vol. %.
The resulting mixture of natural gas and methanol is mixed with the main amount of natural gas in such volume ratio that is necessary to inhibit the hydrate formation in the natural gas on the specific location of its production. The volume concentration of methanol in the natural gas was from 0 to 0.03 vol. %. It should be noted that the concentration of the other hydrocarbons (ethane, propane, iso-butane, etc.) is more than 10 vol. % in the natural gas, during its oxidation can be formed a small amounts of other oxygen-containing organic products.