Method for converting carbon dioxide into fuel gas

Abstract

In the method of the present invention, carbon dioxide is converted into a fuel gas. The method comprises the steps of feeding carbon dioxide, an alkane and carbon to a reactor (3) and heating the reactor (3) to a temperature at which pyrolysis occurs. A fuel gas comprising carbon monoxide, hydrogen and methane is obtained as a reaction product and collected in a gas container.

Description

[Technical field]

[0001] The present invention relates to a method for converting carbon dioxide into a fuel gas. [Background technology]

[0002] Carbon capture and utilization is critical to mitigating climate change. The percentage of carbon dioxide in the atmosphere has increased from 320 ppm in the 1970s to 420 ppm today, primarily due to fossil fuel emissions into the atmosphere.

[0003] As a result, new methods for capturing and utilizing carbon dioxide have been developed, although most are still in the research stage.

[0004] One of these methods, converting carbon dioxide into fuel gas, is twice as expensive as other power generation methods and is therefore not economically viable.

[0005] However, the availability of renewable synthetic fuels not only reduces our dependence on fossil fuels, but also makes the production of these fuel gases interesting and easy to handle, since the large amounts of carbon dioxide available are available from industry or directly from the atmosphere. However, the carbon dioxide molecule is chemically inert and very stable, and the reactions are very energy consuming.

[0006] There are a variety of ways to convert carbon dioxide into syngas, including biological or catalytic production of methane, or conversion of carbon dioxide and hydrogen to syngas and then the Fischer-Tropsch process to produce hydrocarbons.

[0007] However, all these methods are very energy consuming in that they require the sole production of hydrogen, for example by electrolysis, and are very expensive to implement. So far, the production plants that produce synthesis gas are also energy consuming.

[0008] An object of the present invention is an improved method for producing fuel gas from carbon dioxide. Summary of the Invention

[0009] The method for converting carbon dioxide into fuel gas of the present invention includes the steps of supplying carbon dioxide, an alkane, and carbon as reactants to a reactor, and heating the reactor to a temperature at which pyrolysis occurs to obtain a fuel gas containing carbon dioxide. Carbon monoxide, hydrogen, and methane are obtained as reaction products.

[0010] Preferred embodiments of the invention have the features of the dependent claims.

[0011] Therefore, the alkanes used for pyrolysis are preferably paraffinic hydrocarbons C 28 H 58 This is octacosane.

[0012] Such compounds are therefore carbon dioxide, octacosane and carbon, preferably biocarbon, provided as inputs, and carbon monoxide, hydrogen and methane obtained as outputs: CO2+(C 28 H 58 +C) → CO+H2+CH4

[0013] The reactor is heated to a temperature of 700°C to 1000°C, preferably 700°C to 800°C.

[0014] When the temperature rises to about 400°C, the reactants begin to decompose, in other words, gas evolution begins when carbon dioxide and a mixture of alkanes and carbon in proportions are introduced, i.e., the content of alkanes and carbon relative to carbon dioxide is 1.5-2%.

[0015] The method has already been adopted in experiments, for example, by adding 10 g of biocarbon (C) and 5 mL of octacosane (C) per kilogram of carbon dioxide (CO2). 28 H 58 In the tests carried out, 10 kg of CO2 was added to the water at atmospheric pressure, resulting in a 10 m 3 of fuel gas was produced.

[0016] The reactors used are cast iron vessels with an electrical resistance of 2 kW or graphite vessels equipped with a separate heating source. Recovery of fuel gas production is carried out in an intermediate gas vessel with a pressure of 1 MPa.

[0017] Methane (CH4) has many advantages as a fuel compared to hydrogen, and is used as a fuel for automobiles, etc., so there is demand for it. Methane is not explosive like hydrogen (H2), and is easy to store.

[0018] Fuel gas obtained from methane is a mixture of carbon monoxide (CO), hydrogen (H2) and methane (CH4). Hydrogen can be separated from the resulting fuel gas if the following conditions are met:

[0019] The following is an example of the method of the present invention. Working Example

[0020] Carbon dioxide (CO2) is supplied from a cylinder to a reactor heated to 700°C at a supply rate of 10 kg per hour.

[0021] A mixture of 50 g of liquid octacosane and 100 g of carbon is prepared in a mixer. 28 H 58 A mixture of 50 g of ethanol (CO2) and 100 g of biocarbon (C) is fed as a mixture from a container through a screw feeder into the same reactor. The proportion of carbon dioxide is 1 kg of CO2 per 15 g of the above mixture.

[0022] After reacting for 1 hour, the reaction products of fuel gas containing carbon monoxide (CO), hydrogen (H2) and methane (CH4) are collected in a gas container and can then be fed to, for example, a power-generating gas turbine to generate electricity.

[0023] During capture, the resulting fuel gas is combusted and the flame color changes from red to blue depending on the reaction temperature. Because CO2 has a cooling effect, the reaction temperature may vary, but in ideal conditions of 700-800°C, the fuel gas is pure and the flame color changes to blue.

[0024] The flame color depends on the purity of the gas; if it contains a large amount of dust it will be reddish, and if it contains a small amount of dust it will be blue.

[0025] The drawings of the invention will now be described with reference to examples of the invention. [Brief description of the drawings]

[0026] [Figure 1] FIG. 1 is a schematic diagram of a reactor used in the process of the present invention. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0027] FIG. 1 is a schematic diagram of the reaction apparatus used in the process of the present invention.

[0028] In the process of the present invention, carbon dioxide (CO2) is converted to a fuel gas by feeding it from a container or tank 1 to a reactor 3 where it is heated to a temperature in excess of 700°C, sufficient for a pyrolysis reaction to occur between the reactors.

[0029] Alkane C n H 2n+2 , preferably octacosane (C 28 H 58 ) is mixed and added to the same reactor 3 together with biocarbon 10 (C) from another vessel 2 with a mixer.

[0030] Fuel gas containing carbon monoxide (CO), hydrogen (H2) and methane (CH4) is obtained as the reaction product and collected in a gas container 4.

[0031] Preferred embodiments of the invention have the features of the dependent claims.

[0032] Therefore, the alkanes used for pyrolysis are solid paraffinic hydrocarbons C 28 H 58 Preferably, the compound is octacosane,

Claims

1. 1. A method for converting carbon dioxide into a fuel gas, comprising the step of feeding carbon dioxide and carbon to a reactor (3), producing the fuel gas by heating the reactor (3) to a temperature at which pyrolysis occurs, resulting in reaction products comprising carbon monoxide, hydrogen and methane, the method further comprising the step of feeding an alkane to the reactor (3).

2. 2. The method of claim 1, wherein the alkane is octacosane and the carbon is biocarbon.

3. The process according to claim 1 or 2, wherein the reactor is heated to a temperature of from 700°C to 1000°C, preferably 800°C.

4. The carbon dioxide (CO ２ 4. The method according to claim 1, wherein the alkane is added to the reactor (3) together with biocarbon (C) from another vessel (2) having a mixer by mixing the alkane with the biocarbon (C) from another vessel (2) having a mixer.

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