Modular Thermophilic Anaerobic Digester with Internal Baffles
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Solution Overview
Problem
Current anaerobic digester systems face challenges such as temperature maintenance issues, uneven heating, and accumulation of inorganic and heavy organic matter, leading to reduced efficiency and longer digestion times, which necessitate additional processing steps and increased costs.
Innovation Solution
A thermophilic anaerobic digester system with a modular, sloped design and internal baffles ensures uniform temperature and agitation, allowing for continuous operation with contaminated feedstock, reducing hydraulic retention time, and achieving higher pathogen kill rates and volatile solids destruction.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If in-ground lagoons are used for anaerobic digestion, then construction cost is reduced, but temperature control and pathogen kill efficiency deteriorate
Solution Approach 1:
The digester is divided into multiple zones with internal baffles that create separate compartments. This segmentation allows different temperature zones and flow patterns within the same structure, enabling thermophilic conditions in specific zones while maintaining overall system simplicity and cost-effectiveness.
Solution Approach 2:
The patent applies local heating elements and insulated zones specifically where thermophilic conditions are needed, rather than heating the entire structure uniformly. This localized approach to temperature control achieves pathogen kill and digestion efficiency while minimizing energy consumption and construction costs.
2Temperature
If conventional heating coils are used in mesophilic digesters, then temperature maintenance is achieved, but heating uniformity and agitation effectiveness worsen
Solution Approach 1:
The heating system transitions from one-dimensional coil heating to a multi-dimensional approach using heated walls, floor, and ceiling surfaces. This creates uniform heat distribution throughout the digester volume, eliminating hot and cold spots while maintaining energy efficiency.
Solution Approach 2:
The patent introduces an intermediary heat transfer medium (such as heated water or thermal oil) that circulates through embedded pipes in the digester walls and floor. This intermediary ensures uniform heat distribution throughout the structure, solving the non-uniform heating problem of conventional coil systems.
3Reliability
If long hydraulic retention time is used in conventional digesters, then digestion completeness is improved, but throughput and productivity deteriorate
Solution Approach 1:
The patent changes the temperature parameter from mesophilic (35-40°C) to thermophilic (50-60°C), which accelerates the digestion rate by a factor of 2-3. This parameter change allows the system to maintain high digestion completeness with significantly shorter hydraulic retention times, thereby increasing throughput and productivity.
Solution Approach 2:
The digester employs dynamic mixing and flow patterns that enhance mass transfer and substrate availability to microorganisms. This dynamic operation, combined with thermophilic temperatures, maximizes digestion efficiency within reduced retention times, enabling both completeness and high productivity.
4Reliability
If thermophilic temperatures are applied, then pathogen kill and digestion rate are improved, but energy consumption and temperature control complexity worsen
Solution Approach 1:
The patent combines multiple functions into a single integrated system: the heated walls serve both as structural boundaries and as heat transfer surfaces; the mixing system simultaneously prevents scum formation and distributes heat; and the digester structure itself acts as a heat retention element. This merging reduces overall energy consumption while maintaining thermophilic conditions.
Solution Approach 2:
The digester design allows the process heat from the exothermic digestion reactions to be retained and reused within the insulated structure. The thermophilic conditions create a self-sustaining thermal environment where the digestion process itself contributes to maintaining the required temperature, reducing external energy input requirements.
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 system achieves faster throughput, higher gas production, superior pathogen and BOD/COD destruction, and better odor control, eliminating the need for secondary digestion processes and reducing operational and project costs.
Implementation Method 1
the heat is transferred by a combination of conduction and convection through the wall and then across the full width of the plug flow within the channel
Implementation Method 2
the heat is transferred by a combination of conduction and convection through the wall and then across the full width of the plug flow within the channel
Implementation Method 3
A thermophilic anaerobic digester system with a modular, sloped design and internal baffles ensures uniform temperature and agitation, allowing for continuous operation with contaminated feedstock
Data Source
AI summary
A new approach is proposed that contemplates systems and methods to support an environmentally-friendly, “green” thermophilic anaerobic digestion system. The system includes a thermophilic anaerobic digester as well as various independent modular anaerobic units to generate bio-methane from certain organic energy sources, including but not limited to, among other things, green municipal waste, restaurant and organic waste and effluents from industries such as breweries, grocery stores, food processing plants, granaries, wineries, pulp and paper mills, ethanol and biodiesel plants, fat and animal rendering, agricultural field crops, organic sludge accumulation within lagoons and waterways, marine organic matter and animal manure.