Biological CO2 Conversion to Hydrogen and Methane
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Solution Overview
Problem
Current methods for reducing carbon dioxide emissions and producing hydrogen and methane are inefficient, with high energy consumption, costly purification processes, and limitations in carbon dioxide utilization, particularly in biological conversion processes.
Innovation Solution
A biological process using specific hydrogen-producing, acetogenic, and methanogenic bacteria to convert carbon dioxide into hydrogen and methane with reduced energy consumption, achieving high yields and purity, and producing additional organic acids and minerals for various sectors.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If carbon dioxide is converted into methane through biological means using methanogenic microorganisms, then methane production is achieved, but the process requires high energy consumption and produces undesirable gases that require costly purification
Solution Approach 1:
The patent divides the biological conversion process into separate functional stages: first converting CO2 to hydrogen via hydrogen-producing bacteria, then converting hydrogen to methane via methanogenic microorganisms. This segmentation allows optimization of each stage independently, improving overall efficiency and reducing energy losses associated with single-stage direct methanogenesis.
Solution Approach 2:
Hydrogen serves as an intermediary substance in the patent's approach. Instead of directly converting CO2 to methane (which requires high energy input), the process uses hydrogen as an intermediate carrier: CO2 → H2 → CH4. This two-step pathway via hydrogen production and consumption enables more efficient energy utilization while maintaining high methane production yields.
2Productivity
If carbon dioxide is converted into methane through biological means, then methane production is achieved, but parallel fermentations produce undesirable gases requiring purification systems that increase investment and operating costs
Solution Approach 1:
The patent employs specific, specialized microorganisms with defined functional characteristics: hydrogen-producing bacteria (Clostridium, Rhodobacter, Enterobacter) for the first stage and methanogenic microorganisms (Methanobacterium, Methanosarcina, Methanothermobacter) for the second stage. This selection of organisms with specific metabolic pathways ensures that the desired products (hydrogen and methane) are produced while minimizing unwanted by-products, thereby reducing the need for complex purification systems.
Solution Approach 2:
The patent converts the potential harm of CO2 emissions into a beneficial process by using CO2 as the starting substrate for biological conversion. The CO2 that would otherwise be a harmful greenhouse gas is transformed into valuable hydrogen and methane products through controlled biological processes, eliminating the need for complex purification to remove CO2 while simultaneously producing useful fuels.
3Quantity of substance
If hydrogen is produced by electrolysis for carbon dioxide conversion, then hydrogen is obtained, but the process absorbs high electric power
Solution Approach 1:
The patent replaces the electrolytic process (which requires high electric power input) with a biological hydrogen production process using hydrogen-producing bacteria. These microorganisms convert CO2 and water into hydrogen through biological metabolism, eliminating the need for energy-intensive electrolysis while maintaining hydrogen production capability. This substitution of biological processes for electrochemical processes significantly reduces energy consumption.
Solution Approach 2:
The hydrogen-producing bacteria perform the hydrogen generation function autonomously through biological metabolism, utilizing CO2 and water as substrates. The system is self-sustaining, with the bacteria naturally converting CO2 to hydrogen without requiring external electric power input. This biological self-service approach replaces the energy-intensive electrolysis process, enabling hydrogen production with minimal energy consumption.
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
The process effectively reduces atmospheric carbon dioxide concentrations while producing hydrogen and methane efficiently, with low energy consumption and competitive costs, and generates valuable biological materials.
Implementation Method 1
introducing carbon dioxide in at least one first reactor containing up to 95% by volume of a first culture medium comprising one or more hydrogen-producing bacteria and keeping under continuous stirring in anaerobic conditions until a stationary phase of the growth of the one or more hydrogen-producing bacteria is achieved
Implementation Method 2
introducing the gaseous mixture of hydrogen and residual carbon dioxide obtained in step (i) in at least one of: a) at least one second reactor comprising up to 95% by volume of a second culture medium which comprises one or more acetogenic bacteria and keeping under continuous stirring in anaerobic conditions
Implementation Method 3
b) at least one third reactor comprising up to 95% by volume of a third culture medium comprising one or more methanogenic microorganisms and keeping under continuous stirring in anaerobic conditions, obtaining a third fermented culture medium and a gaseous mixture comprising methane
Data Source
AI summary
A process for the biological production of hydrogen and/or methane by absorption and biological conversion of carbon dioxide, includes the steps of being performed by co-culture of one or more hydrogen-producing bacteria in at least one first reactor, and one or more acetogenic bacteria in at least one second reactor, and/or one or more methanogenic microorganisms in at least one third reactor.