Biomimetic Two-Phase Anaerobic Fermentation Reactor
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Solution Overview
Problem
Anaerobic dry fermentation of organic solid wastes faces challenges such as severe acidification and ammonia inhibition, leading to reduced biogas output, particularly when using livestock feces as a substrate, due to high dry matter content and sensitivity of methanogenic microorganisms to environmental factors.
Innovation Solution
An integrated two-phase anaerobic dry fermentation reactor based on the biomimetic principle of rumen, featuring a reactor body with separate dry and secondary fermentation chambers, a gas collection system, pH and temperature control, and a biogas slurry backflow spraying device, which employs a filter mesh and ultrafiltration membrane to separate solid and liquid phases, promoting further methane production and avoiding inhibition.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If dry fermentation technology is applied to organic wastes with high dry matter content, then water consumption is reduced and energy efficiency is improved, but severe local acidification and ammonia inhibition occur leading to reduced biogas output
Solution Approach 1:
The reactor is divided into two distinct phases: an upper dry fermentation chamber for solid substrate fermentation and a lower liquid storage chamber for biogas slurry collection. This segmentation allows separate optimization of conditions for each phase, preventing acidification in the dry zone while collecting inhibitory substances in the liquid zone, thereby maintaining high biogas output.
Solution Approach 2:
A filter mesh is introduced as an intermediary component between the dry fermentation chamber and liquid storage chamber. This filter mesh separates solid residues from liquid biogas slurry, allowing efficient removal of ammonia and organic acids from the fermentation environment, thus preventing inhibition while maintaining productivity.
2Loss of substance
If high dry matter content substrate is used in anaerobic fermentation, then less water consumption and lower secondary pollution are achieved, but fluidity is poor resulting in inadequate heat and mass transfer
Solution Approach 1:
The reactor design utilizes vertical spatial arrangement with the dry fermentation chamber positioned above the liquid storage chamber. This dimensional arrangement enables gravity-driven flow of biogas slurry downward through the filter mesh, enhancing mass transfer without requiring additional water for fluidization, thus maintaining low water consumption while improving transfer efficiency.
3Productivity
If methanogenic microorganisms are exposed to high ammonia concentration from livestock feces, then substrate utilization is maintained, but ammonia inhibition causes sharp drop in biogas output
Solution Approach 1:
The filter mesh system extracts and separates liquid biogas slurry containing high concentrations of ammonia and organic acids from the dry fermentation chamber. This extracted liquid is collected in the lower storage chamber, effectively removing inhibitory substances from the microbial environment while allowing continued substrate utilization in the dry phase.
4Productivity
If continuous stirring is applied to improve heat and mass transfer in dry fermentation, then fermentation efficiency is enhanced, but energy consumption and disruption of microbial environment increase
Solution Approach 1:
Instead of continuous stirring, the system employs periodic or intermittent mixing actions that are sufficient to maintain adequate heat and mass transfer. This periodic action reduces energy consumption while still achieving the necessary fermentation efficiency, and minimizes disruption to the sensitive methanogenic microorganism environment.
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 reactor design enhances fermentation efficiency by separating phases, reusing biogas slurry, and controlling ammonia and acid levels, resulting in improved methane production and reduced pollution, suitable for treating organic wastes with high dry matter content like livestock feces, crop straws, and dewatered sludge.
Implementation Method 1
a filter mesh and ultrafiltration membrane to separate solid and liquid phases
Implementation Method 2
anaerobic fermentation of the raw material having a dry matter content of 20%-40%
Data Source
AI summary
An integrated two-phase anaerobic dry fermentation reactor based on a biomimetic principle of rumen includes a reactor body; wherein the reactor body includes a dry fermentation chamber, a secondary fermentation chamber, and a liquid storage chamber. The dry fermentation chamber is arranged at an upper portion of the reactor body. The liquid storage chamber is arranged at a bottom of the reactor body. The secondary fermentation chamber is arranged between the dry fermentation chamber and the liquid storage chamber in the reactor body. The dry fermentation chamber is connected to the secondary fermentation chamber by a porous structure.