Classifications

• • C—CHEMISTRY; METALLURGY
  • C07—ORGANIC CHEMISTRY
  • C07C—ACYCLIC OR CARBOCYCLIC COMPOUNDS
  • C07C1/00—Preparation of hydrocarbons from one or more compounds, none of them being a hydrocarbon
  • C07C1/02—Preparation of hydrocarbons from one or more compounds, none of them being a hydrocarbon from oxides of a carbon
  • C07C1/12—Preparation of hydrocarbons from one or more compounds, none of them being a hydrocarbon from oxides of a carbon from carbon dioxide with hydrogen
• • H—ELECTRICITY
  • H01—ELECTRIC ELEMENTS
  • H01M—PROCESSES OR MEANS, e.g. BATTERIES, FOR THE DIRECT CONVERSION OF CHEMICAL ENERGY INTO ELECTRICAL ENERGY
  • H01M8/00—Fuel cells; Manufacture thereof
  • H01M8/06—Combination of fuel cells with means for production of reactants or for treatment of residues
• • C—CHEMISTRY; METALLURGY
  • C07—ORGANIC CHEMISTRY
  • C07C—ACYCLIC OR CARBOCYCLIC COMPOUNDS
  • C07C29/00—Preparation of compounds having hydroxy or O-metal groups bound to a carbon atom not belonging to a six-membered aromatic ring
  • C07C29/15—Preparation of compounds having hydroxy or O-metal groups bound to a carbon atom not belonging to a six-membered aromatic ring by reduction of oxides of carbon exclusively
  • C07C29/151—Preparation of compounds having hydroxy or O-metal groups bound to a carbon atom not belonging to a six-membered aromatic ring by reduction of oxides of carbon exclusively with hydrogen or hydrogen-containing gases
  • C07C29/1516—Multisteps
  • C07C29/1518—Multisteps one step being the formation of initial mixture of carbon oxides and hydrogen for synthesis
• • C—CHEMISTRY; METALLURGY
  • C25—ELECTROLYTIC OR ELECTROPHORETIC PROCESSES; APPARATUS THEREFOR
  • C25B—ELECTROLYTIC OR ELECTROPHORETIC PROCESSES FOR THE PRODUCTION OF COMPOUNDS OR NON-METALS; APPARATUS THEREFOR
  • C25B3/00—Electrolytic production of organic compounds
  • C25B3/20—Processes
  • C25B3/25—Reduction
• • H—ELECTRICITY
  • H01—ELECTRIC ELEMENTS
  • H01M—PROCESSES OR MEANS, e.g. BATTERIES, FOR THE DIRECT CONVERSION OF CHEMICAL ENERGY INTO ELECTRICAL ENERGY
  • H01M8/00—Fuel cells; Manufacture thereof
  • H01M8/04—Auxiliary arrangements, e.g. for control of pressure or for circulation of fluids
• • Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
  • Y02—TECHNOLOGIES OR APPLICATIONS FOR MITIGATION OR ADAPTATION AGAINST CLIMATE CHANGE
  • Y02E—REDUCTION OF GREENHOUSE GAS [GHG] EMISSIONS, RELATED TO ENERGY GENERATION, TRANSMISSION OR DISTRIBUTION
  • Y02E60/00—Enabling technologies; Technologies with a potential or indirect contribution to GHG emissions mitigation
  • Y02E60/30—Hydrogen technology
  • Y02E60/32—Hydrogen storage
• • Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
  • Y02—TECHNOLOGIES OR APPLICATIONS FOR MITIGATION OR ADAPTATION AGAINST CLIMATE CHANGE
  • Y02E—REDUCTION OF GREENHOUSE GAS [GHG] EMISSIONS, RELATED TO ENERGY GENERATION, TRANSMISSION OR DISTRIBUTION
  • Y02E60/00—Enabling technologies; Technologies with a potential or indirect contribution to GHG emissions mitigation
  • Y02E60/30—Hydrogen technology
  • Y02E60/36—Hydrogen production from non-carbon containing sources, e.g. by water electrolysis
• • Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
  • Y02—TECHNOLOGIES OR APPLICATIONS FOR MITIGATION OR ADAPTATION AGAINST CLIMATE CHANGE
  • Y02E—REDUCTION OF GREENHOUSE GAS [GHG] EMISSIONS, RELATED TO ENERGY GENERATION, TRANSMISSION OR DISTRIBUTION
  • Y02E60/00—Enabling technologies; Technologies with a potential or indirect contribution to GHG emissions mitigation
  • Y02E60/30—Hydrogen technology
  • Y02E60/50—Fuel cells

Definitions

• the present invention relates to a method for capturing carbon dioxide from a gaseous mixture containing carbon dioxide, e.g., from the atmosphere, and subsequently using this carbon dioxide for the production of fuel.
• Greenhouse gases include carbon dioxide, methane, nitrous oxide and water vapor. While greenhouse gases occur naturally in the atmosphere, human activities also produce greenhouse gas emissions and are responsible for creating new ones. Carbon dioxide (CO 2 ) is the most common greenhouse gas released by human activities, resulting from the extensive use of fossil fuel (coal, petroleum, natural gas). One of the main challenges modern civilization is facing is the increase of carbon dioxide in the atmosphere, affecting the greenhouse effect and global warming. Another problem arises from the extensive use of fossil fuel thus diminishing the global fuel reserves.
• Renewable energy sources that capture their energy from existing flows of energy, from on-going natural processes, such as sunshine, wind, flowing water, biological processes and geothermal heat flows, can be used for generating electricity, and there is a growing demand for methods of producing fuel using electricity.
• U.S. Pat. No. 4,140,602 discloses a chemical method for combustible fuel production by converting carbon dioxide in the atmosphere to a carbonate such as an alkali carbonate, following which the recovered carbonate is combined with hydrogen gas to produce combustible fuels e.g. methane and methanol.
• the method includes the additional step of reacting the alkali carbonate with calcium hydroxide to form calcium carbonate.
• the disadvantages of this method resides in the use of the strong base compound Ca(OH) 2 , forming CaCO 3 , that requires considerable amount of energy for the thermal release of CO 2 .
• the present invention relates to a method for producing combustible fuels from a gaseous mixture containing carbon dioxide, which comprises:
• the method of the present invention enables the production of combustible fuels, using as preferred starting material the highly available atmospheric carbon dioxide, and returning the CO 2 produced by fuel combustion to the atmosphere, thus maintaining the equilibrium of the CO 2 in the atmosphere.
• the method is based on well known in the art reactions such as thermal catalytic and electrochemical reactions, utilizing the reversibility of these reactions and carrying out the reverse reaction by modifying the operating pressure and/or the electrical voltage supplied to the process.
• the reaction between the CO 2 and K 2 CO 3 in step (i) may be performed by bubbling air in water through an aqueous solution of K 2 CO 3 or by spraying droplets of K 2 CO 3 in aqueous solution into a stream of air.
• the atmospheric CO 2 reacts with the K 2 CO 3 to form KHCO 3 according to the following reaction: K 2 CO 3 +H 2 O+CO 2 ⁇ 2KHCO 3
• the CO 2 is released by heating the KHCO 3 to a temperature sufficient to liberate the CO 2 , according to the following reaction, thus recycling the K 2 CO 3 : 2KHCO 3 +Heat ⁇ K 2 CO 3 +H 2 O+CO 2
• the CO 2 is released from the KHCO 3 obtained by an electrochemical process, according to the following reaction: HCO 3 ⁇ ⁇ e ⁇ .OH+CO 2 4(.OH) ⁇ 2H 2 O+O 2
• step (ii) The CO 2 obtained in step (ii) is then reacted with hydrogen to produce combustible fuels, such as methane and methanol.
• the reaction of CO 2 and hydrogen is conducted as a thermal catalytic reaction.
• One possible thermal catalytic reaction is a reverse operation of methane reforming.
• methane is brought into contact with (excess) steam at high temperature and pressure, typically 800-1000° C. and 30-40 bar, over a catalyst, to produce a mixture of H 2 , CO and CO 2 .
• the process is usually carried out in fixed bed or fluidized bed membrane reactors, using a Ni as the preferred catalyst, because of its low cost, or a noble metal catalyst such as Ru, Rh, Pd, Ir or Pt.
• the reverse methane reforming according to the invention is carried in the same type of reactors and using the same catalysts as in steam methane reforming, but using pressures varying according to the characteristics of the specific process, said pressure being always higher than the pressure used for the methane reforming.
• reaction of CO 2 and hydrogen according to the invention is an electrochemical process, such as a reverse operation of a fuel cell.
• a fuel cell is an electrochemical energy conversion device that converts the chemical energy of a fuel, e.g. hydrogen, and an oxidant, e.g. oxygen, to electrical energy and heat, without combustion.
• the device is similar to a battery but, unlike a battery, the fuel cell is designed for continuous replenishment of the reactants consumed, i.e., the fuel and the oxidant are typically stored outside of the fuel cell and transferred into the fuel cell as the reactants are consumed. In a typical fuel cell, the fuel is consumed at the anode and the oxidizer is consumed at the cathode.
• Fuel cells are usually classified by the type of electrolyte they use, and include phosphoric acid-based, proton exchange membrane, solid polymer, molten carbonate, solid oxide, alkaline, direct methanol, regenerative, zinc-air and protonic ceramic fuel cells.
• a hydrocarbon such as methane
• said hydrocarbon is reacted with oxygen obtained by electrolysis of water within the cell, thus forming CO 2 and hydrogen and generating electricity.
• a reverse operation of a fuel cell is carried out whereby electricity is supplied to a fuel cell containing CO 2 , that reacts with hydrogen formed in situ by electrolysis of water, thus producing the desired hydrocarbon, e.g. methane fuel.
• the electrical voltage supplied to the process is determined based on the characteristics of the specific process performed but it is always higher than the electrical voltage generated in the opposite process, namely, the regular operation of the fuel cell.
• the electrochemical process corresponds to an inverted direct methanol fuel cell (DMFC) and the fuel obtained is methanol.
• DMFC direct methanol fuel cell
• DMFCs are low-temperature fuel cells operating at temperatures of 30-130° C. and using liquid methanol as the electrolyte, according to the reaction: CH 3 OH+ 3/2O 2 ⁇ CO 2 +2H 2 O
• the central component of DMFCs is the membrane electrode assembly, composed of membrane, catalyst and diffusion layers.
• the membrane may be a polymer with acid groups that are capable of splitting off protons and has them migrate through the membrane.
• the diffusion layer passes the fuels to the catalyst layer and removes the combustion products.
• the electrochemical reaction takes place, in which chemical energy is converted into electric energy.
• the catalyst is provided with additives to apply it as a paste on a substrate, and it is usually based on a noble metal, such as platinum and platinum/ruthenium.
• the catalysts used for the reverse operation of the DMFC are the same used in the regular operation mode of the methanol fuel cell, and other parameters such as temperature and electrical voltage supplied to the process are determined based on the characteristics of the specific process performed.
• the electrochemical process corresponds to an inverted molten carbonate fuel cell (MCFC) and the fuel obtained is a hydrocarbon, such as methane.
• MCFC inverted molten carbonate fuel cell
• MCFCs are high-temperature fuel cell operating at temperatures of 600-650° C., and thus can achieve higher fuel-to-electricity and overall energy use efficiencies than low temperature fuel cells.
• the electrolyte used in MCFCs is an alkali carbonate such as Na 2 CO 3 , K 2 CO 3 , Li 2 CO 3 or combinations thereof, that may be retained in a ceramic matrix, e.g. of LiAlO 2 .
• the alkali carbonates melt into a highly conductive molten salt with carbonate ions providing ionic conduction through the electrolyte matrix.
• Nickel and nickel oxide are adequate to promote reaction on the anode and cathode, respectively, and expensive catalysts (noble metals) are not required.
• the fuel consumed in MCFCs is usually a natural gas, mainly methane, and in this case methane and steam are converted into a hydrogen-rich gas inside the fuel cell stack (a process called “internal reforming”).
• internal reforming a process called “internal reforming”.
• the overall reaction performed within the cell is: CH 4 +O 2 ⁇ CO 2 +2H 2
• the operating conditions for the reverse operation of the MCFC are similar to these in the regular operation mode of this cell.
• the exact conditions, as well as the voltage supplied to the process, are determined based on the characteristics of the specific process performed.
• the methane or methanol obtained by the method of the invention may later be converted into longer hydrocarbons, using known chemical reactions.

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• Chemical & Material Sciences (AREA)
• Organic Chemistry (AREA)
• Chemical Kinetics & Catalysis (AREA)
• Engineering & Computer Science (AREA)
• General Chemical & Material Sciences (AREA)
• Electrochemistry (AREA)
• Sustainable Energy (AREA)
• Life Sciences & Earth Sciences (AREA)
• Sustainable Development (AREA)
• Oil, Petroleum & Natural Gas (AREA)
• Manufacturing & Machinery (AREA)
• Materials Engineering (AREA)
• Metallurgy (AREA)
• Hydrogen, Water And Hydrids (AREA)
• Carbon And Carbon Compounds (AREA)
• Inert Electrodes (AREA)

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Cited By (21)

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Citations (5)

• 2005
  • 2005-07-12 WO PCT/IL2005/000739 patent/WO2006006164A2/fr active Application Filing
  • 2005-07-12 KR KR1020077003333A patent/KR20070067676A/ko not_active Application Discontinuation
  • 2005-07-12 AU AU2005261273A patent/AU2005261273A1/en not_active Abandoned
  • 2005-07-12 EP EP05758924A patent/EP1778583A2/fr not_active Withdrawn
  • 2005-07-12 US US11/631,967 patent/US20080072496A1/en not_active Abandoned
  • 2005-07-12 CA CA002579133A patent/CA2579133A1/fr not_active Abandoned
  • 2005-07-12 RU RU2007105092/04A patent/RU2007105092A/ru not_active Application Discontinuation

Patent Citations (5)

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