Process for reducing carbon dioxide to carbon

The process of reacting CO2 with a hydrocarbon in the presence of a catalyst efficiently converts CO2 and CH4 into elemental carbon and water, addressing the challenge of reducing CO2 to elemental carbon in existing technologies.

DE102023005082A1Inactive Publication Date: 2025-06-12KARMANN KLAUS PETER
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Patent Information

Application Number
DE102023005082
Authority / Receiving Office
DE · DE
Patent Type
Applications
Current Assignee / Owner
Filing Date
2023-12-09
Publication Date
2025-06-12
Estimated Expiration
Not applicable · inactive patent

AI Technical Summary

Technical Problem

Current methods are inadequate for efficiently reducing carbon dioxide (CO2) to elemental carbon (C) in a form that can be easily extracted from reaction mixtures.

Method used

A process involving the reaction of CO2 with a hydrocarbon, such as methane (CH4), in the presence of a catalyst like nickel (Ni), ruthenium (Ru), rhodium (Rh), or cobalt (Co), at temperatures between 100 and 800°C and pressures of 1 to 100 bar, to produce elemental carbon and water.

Benefits of technology

This process effectively converts harmful CO2 and CH4 gases into pure carbon, a valuable raw material, and water, while accelerating the reaction with a catalyst and optimizing conditions for efficient carbon extraction.

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Abstract

The present invention is based on the object of providing a process for reducing carbon dioxide (CO2) to carbon (C). This object is achieved according to the invention by a process for reducing carbon dioxide to carbon by reacting carbon dioxide with a hydrocarbon or hydrocarbon mixture. According to a preferred embodiment of the invention, a reaction of CO2 with methane (CH4) to form water (H2O) is provided in the form CO2 + CH4 -> 2C + 2H2O. An advantage of this embodiment of the invention can be seen in the fact that the reaction product carbon (C) is obtained in elemental form and can therefore be easily removed from the preferably gaseous reaction mixture. The process is particularly suitable for decarbonization (CCS), for example, by processing industrial exhaust gases. Numerous industries, such as the steel and cement industries, breweries, sewage treatment plants, waste incineration plants, and biogas-producing processes, emit large amounts of CO2. A biogas stream consists of approximately half methane and half CO2 and is therefore particularly suitable for the application of the process according to the invention.
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Description

The invention is described below with reference to preferred exemplary embodiments.The present invention is based on the object of specifying a process with which carbon dioxide (CO 2) is reduced to carbon (C). This object is achieved according to the invention by a process for reducing carbon dioxide to carbon according to claim 1 by reacting carbon dioxide with a hydrocarbon or hydrocarbon mixture.According to a preferred embodiment of the invention, a reaction of CO 2 with methane (CH 4) to form water (H 2 O) is provided in the form CO 2+ CH 4- >2C+2H 2 O. An advantage of this embodiment of the invention can be seen in the fact that the reaction product carbon (C) is obtained in elemental form and can therefore easily be taken from the preferably gaseous reaction mixture.The reaction of CO 2 to C is advantageously accelerated at temperatures between 100 and 800° C., particularly advantageously between 300 and 600° C., and at pressures of 1 to 100 bar with the aid of a catalyst which contains, for example, elements such as nickel (Ni), ruthenium (Ru), rhodium (Rh) or cobalt (Co).Preferably, the H 2 O formed in the reaction is kept away from the reaction centers of the catalyst by means of a sorbent material such as zeolite, for example.The water formed can also advantageously be removed from the reaction mixture by pyrolysis, electrolysis, photodissociation, condensation or freezing. The reaction centers of the catalyst are preferably kept free from possible carbon deposits by mechanical, acoustic, aerodynamic or other means or by continuous or intermittent recycling of the catalyst.The process is particularly suitable for decarburization ("Carbon Capture and Storage", CCS), for example, by processing industrial waste gases. Numerous industries such as the steel and cement industry, brewing plants, sewage treatment plants, waste incineration plants and biogas producing processes emit large amounts of CO 2. A biogas stream consists approximately half of methane and CO 2 and is therefore particularly suitable for use with the method according to the invention.If only CO 2 or CO 2 is present with excessively low methane additions, methane must be fed in, but this is not oxidized in the process according to the invention. With this method, two gases which are very harmful to climates, CO 2 and CH 4 are converted into pure carbon, a valuable raw material which can be deposited without any problems, and pure water in one process.The enthalpy of reaction of the reaction is 15.25 kJ / mol or 103.65 kJ / mol, depending on whether the heat of condensation of the water formed can be used.

Claims

A process for reducing carbon dioxide to carbon by reacting carbon dioxide with a hydrocarbon or hydrocarbon mixture.The process of claim 1 wherein carbon dioxide reacts with methane to form carbon and water.Process according to one of the preceding claims, in which water formed in the reaction is removed from the reaction by sorption.The method of claim 3 wherein sorption of the water is effected by a sorption catalyst.