Electromethanogenesis reactor
Inventors
Knipe, Jennifer Marie • Baker, Sarah E. • Worsley, Marcus A. • Chandrasekaran, Swetha
Assignees
Lawrence Livermore National Security LLC • Lawrence Livermore National Laboratory LLC
Publication Number
US-11111468-B2
Publication Date
2021-09-07
Expiration Date
2038-04-10
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Abstract
Generation of energy and storage of energy for subsequent use is provided by electromethanogenesis of carbon dioxide into a fuel gas and the storage of the fuel gas for subsequent use. An electromethanogenic reactor includes an anode conductor and a cathode conductor wherein the cathode conductor includes submicron to micron scale pores. Electromethanogenesis microbes and/or enzymes are located in the micron scale pores of the cathode electrode conductor. Carbon dioxide is introduced into the electromethanogenic reactor and the electromethanogenesis microbes/enzymes and the carbon dioxide interact and produce a fuel gas. The fuel gas is stored for subsequent use, for example use in power generation.
Core Innovation
The invention provides the generation and storage of energy through electromethanogenesis of carbon dioxide into a fuel gas, specifically methane, using an electromethanogenic reactor. This reactor comprises an anode conductor and a cathode conductor where the cathode includes submicron to micron scale pores that house electromethanogenesis microbes and/or enzymes. Carbon dioxide is introduced into the reactor to interact with the microbes or enzymes, resulting in the production of a fuel gas that can be stored for subsequent use, such as in power generation.
The problem solved by this invention addresses the limitations of existing electromethanogenesis technologies. Current methods use microbes adsorbed on planar graphite electrodes, which restrict current density and volumetric productivity due to limited electrode interfacial area accessible to microbes. Furthermore, maintaining reactor geometry and density at larger scales is challenging, constraining scalability. There is a need for reactor designs and electrode materials that increase current density and scalability, enabling efficient long-term energy storage, particularly given the rise of abundant renewable energy sources.
The invention proposes the use of 3D printed electrodes made of materials such as graphene aerogels or resorcinol-formaldehyde aerogel with tunable geometry, surface area, and surface chemistry to maximize current density in microbial electromethanogenesis. This approach overcomes prior limitations by allowing control over material pore size to optimize biologically accessible surface area, utilizing either electromethanogenesis microbes or enzymes adsorbed in the cathode pores for charge transfer. The design supports modular, scalable reactors that reduce diffusion limitations and enable flow-through configurations, thus facilitating scalability and commercial viability.
Claims Coverage
The patent claims include four independent claims focusing on apparatus and methods for electromethanogenesis reactors and processes involving 3D printed cathode electrodes with specific structural and functional features.
3D printed cathode electrode with cubic lattice structure
The reactor comprises a 3D printed cathode electrode conductor with cubic lattices having ten orthogonal layers of parallel cylindrical rods, providing submicron to micron scale pores for high surface area.
Incorporation of electromethanogenesis enzymes and microbes within cathode pores
Electromethanogenesis enzymes and microbes are located within the submicron to micron scale pores of the cathode electrode conductor to facilitate charge transfer and methane production.
Use of specific aerogel materials for cathode electrode
The cathode electrode conductor is formed from high porosity materials such as graphene aerogel or resorcinol-formaldehyde aerogel, which allow tuning of pore size, surface chemistry, and conductivity to maximize current density.
Reactor and method configurations enabling enhanced methane production
The apparatus and methods include CO2 sources for introducing carbon dioxide into the reactor and electrical loads connected to the anode and cathode electrode conductors to provide current density and produce methane gas, with storage systems for the fuel gas.
3D printed cathode electrode having increased thickness and pore extension
The cathode electrode conductor is designed with a thickness greater than standard electrodes and pores that extend from the surface into the 3D printed electrode, enhancing enzyme and microbe accessibility and current density.
The claims collectively cover a 3D printed electromethanogenesis reactor system and method that utilize high surface area, porous, and tunable aerogel cathodes with embedded microbes or enzymes to produce methane efficiently from carbon dioxide, including structural specifics of the cathode and integration with CO2 sources and electrical loads for scalable energy generation and storage.
Stated Advantages
Maximized current density due to controlled material pore size and high conductivity of graphene aerogels over a wide pore size range.
Increased current density and wider operating conditions enabled by using adsorbed enzymes to mediate charge transfer instead of whole microbial cultures.
Maximized volumetric productivity by 3D printing electrodes to optimize space utilization, reduce diffusion limitations, and enable modular, scalable, and flow-through reactor designs suitable for commercialization.
Energy storage as methane leverages existing infrastructure and results in CO2 consumption, thereby reducing climate impacts compared to coal-fired power plants.
The process is potentially less capital and energy intensive than chemical conversion methods, leveraging microbial efficiency.
Documented Applications
Energy storage through conversion of renewable energy and CO2 into methane usable in power generation.
CO2 mitigation via biological conversion of carbon dioxide into methane fuel gas.
Industrial biogas production using microbial methanogenesis.
Production of other fuels or specialty chemicals, such as hydrogen peroxide or acetate, from CO2 via microbial electrosynthesis.
Applications in fuel synthesis and syngas production.
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