Anaerobic Codigester Control Using Linear Programming and Alkalinity Feedback
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Solution Overview
Problem
Current anaerobic digestion processes in biogas plants face challenges in optimizing methane production and operational stability due to variability in organic waste mixtures, requiring more robust and comprehensive monitoring and control methods, especially in centralized codigestion systems.
Innovation Solution
A computer-implemented control method using linear programming to determine optimal substrate proportions and hydraulic residence time, coupled with real-time monitoring and adjustment of physical and chemical parameters, to maximize methane production and maintain process stability.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If linear programming is used to optimize substrate proportions and hydraulic residence time, then methane production is maximized, but the system requires complex real-time monitoring and control of multiple physical and chemical parameters
Solution Approach 1:
The system pre-determines optimal substrate proportions and hydraulic residence time using linear programming before the digestion process begins. This preliminary optimization of operational parameters allows the system to achieve maximum methane production while avoiding the need for complex real-time adjustments, thereby reducing monitoring and control complexity
Solution Approach 2:
The system implements real-time monitoring of physical and chemical parameters (pH, temperature, substrate concentration) and uses this feedback to maintain optimal digestion conditions. This continuous feedback mechanism ensures that the pre-determined optimal parameters are sustained, enabling high methane production without requiring complex adaptive control
2Reliability
If real-time monitoring and adjustment of operational parameters is implemented, then process stability is maintained, but the ease of operation decreases
Solution Approach 1:
The system automatically monitors and adjusts operational parameters (substrate proportions, hydraulic residence time, pH, temperature) without requiring constant manual intervention. The control system self-regulates to maintain optimal digestion conditions, ensuring process stability while simplifying operator tasks to routine monitoring and basic adjustments
3Productivity
If the system dynamically adjusts substrate mixtures to optimize methane production, then productivity increases, but the reliability of maintaining stable digestion conditions may be compromised
Solution Approach 1:
The system pre-calculates optimal substrate proportions using linear programming that simultaneously maximizes methane production and maintains digestion stability. By determining the best substrate mixture composition before implementation, the system achieves high productivity while ensuring reliable and stable digestion conditions through scientifically optimized formulations
Solution Approach 2:
The system dynamically adjusts substrate mixture parameters (composition, concentration, proportions) based on real-time monitoring data and linear programming optimization. These controlled parameter changes enable the system to adapt to varying feedstock qualities and maintain both high methane production and stable digestion conditions by continuously optimizing the substrate mixture parameters
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 method effectively optimizes methane production and stabilizes anaerobic digestion processes by dynamically adjusting substrate mixtures and operational conditions, enhancing the efficiency and reliability of biogas production in anaerobic codigestion systems.
Implementation Method 1
Anaerobic digestion is a biological process whereby any organic residue may be transformed into biogas (mixture of methane and carbon dioxide) through a complex reaction mechanism, including series and parallel reactions, which are catalyzed by different groups of microorganisms
Data Source
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AI summary
The invention relates to a method and a computer program product for controlling anaerobic codigesters. The anaerobic codigestion of multiple substrates improves the production of methane and the quality of the gas and the digested product if the complementary characteristics of the different waste products are used appropriately. To this end, an optimum mixture must be defined, which maximises the conversion of COD to methane without causing destabilisation in the digester. The invention proposes a control strategy which calculates the optimum mixture of the supply by means of optimisation by linear programming, and maintains the stability of the system by following a physical-chemical parameter of the process (alkalinity ratio).