MEC Stack Gas Inlet Segmentation for Methane Production
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Solution Overview
Problem
Microbial Electrolysis Cell (MEC) stacks face inefficiencies due to high volumetric requirements, suboptimal carbon feeding strategies, and physico-chemical gradients, leading to reduced methane production and energy inefficiency.
Innovation Solution
A method to regulate gas gradients in MEC stacks by measuring current, voltage, pH, and oxidation reduction potential, and strategically feeding input gases through multiple inlets to optimize hydrogen and CO2 ratios, pH, and temperature, while degassing the stack to enhance methane production efficiency.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Device complexity
If input gas is delivered to one inlet at the first MEC cell and flows sequentially through subsequent cells, then the system structure is simple, but volumetric requirements increase and reaction efficiency decreases
Solution Approach 1:
The gas delivery system is segmented into multiple independent gas inlets, with each inlet serving specific MEC cells. This segmentation allows each cell to receive optimized gas supply independently, improving reaction efficiency while maintaining manageable system complexity through modular architecture.
Solution Approach 2:
Different MEC cells are assigned different gas inlet configurations based on their specific operational requirements. This local quality approach ensures that each cell receives the appropriate gas flow and composition for optimal methane production, rather than using a uniform delivery system for all cells.
2Productivity
If large volumes of input gas are supplied to meet optimal reaction requirements, then reaction efficiency improves, but system volume and costs increase
Solution Approach 1:
The system optimizes gas volume by changing operational parameters including gas flow rates, pressure, and composition for each inlet. This allows achieving optimal reaction efficiency with reduced overall gas volumes through precise parameter control rather than relying on large volumetric supply.
3Ease of operation
If input gas is fed sequentially through all MEC cells, then system operation is simplified, but carbon source demand is not met and electron donors are unused
Solution Approach 1:
The sequential gas delivery is segmented into multiple parallel delivery paths through different inlets. This allows carbon sources and electron donors to be distributed to specific cells that need them, improving utilization efficiency while maintaining operational simplicity through a standardized multi-inlet configuration.
Solution Approach 2:
The system incorporates monitoring of carbon source demand and electron donor utilization to dynamically adjust gas distribution through different inlets. This feedback mechanism ensures optimal matching of gas supply with cellular needs, improving productivity while maintaining simple operation through automated control.
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
This approach improves methane production efficiency, reduces energy consumption, and creates optimal conditions for microbial metabolism, allowing for higher conversion rates and more efficient resource use in MEC stacks.
Implementation Method 1
The system achieves the combination of electrolysis and methane production in one single reactor, the so called MEC. If within the MEC methanogenic microorganisms reside e.g. in the cathode compartment or at the cathode, the MEC will be regarded as bio-electromethanation cell.
Implementation Method 2
The reactor may comprise a single compartment, or the cathodic compartment or chamber, which may be separated from the anodic compartment or chamber, via e.g. a semipermeable membrane. In some embodiments of the state of the art methanogenesis by the methanogenic microorganisms (e.g. methanogens or archaea) takes place directly in the bio-cathode compartment, whereby the electron flow required for the cathodic reduction of CO2 to methane is compensated in the anode compartment by water oxidation.
Implementation Method 3
The MEC stack comprises two or more gas inlets for an input gas distributed throughout the MEC stack, with at least one gas inlet arranged before each MEC cell of the MEC stack.
Implementation Method 4
The MEC stack comprises at least one degassing element to extract at least one produced gas, wherein at least one degassing element is arranged after a last MEC cell of the MEC stack.
Data Source
AI summary
The present invention provides MEC stack with several or multiple MEC cells comprising at least one gas inlet and at least one degassing element as well as methods to improve the bio-electromethanation reaction catalysed by bio catalysts in these MEC stacks.