Fermenter Volume Control Using Flexible Membrane
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Solution Overview
Problem
Methane losses occur during transitions in the fermentation process due to the dead volume of the headspace in the fermenter, which reduces overall efficiency and requires additional gas handling systems for lean gas disposal.
Innovation Solution
A method that reduces the fermenter volume by using a flexible, gas-tight membrane to minimize the headspace, allowing for volume adjustments to match gas production fluctuations and enabling efficient gas utilization by controlling gas composition during phase transitions.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If the fermenter maintains a fixed volume with a gas-filled headspace to accommodate biomass loading and gas production, then the fermenter can handle process phase transitions, but methane losses occur due to mixing of process gases in the headspace
Solution Approach 1:
The patent applies a flexible membrane inside the fermenter that can dynamically change the volume of the gas-filled headspace. During biomass loading, the membrane allows headspace expansion to accommodate the incoming material. During fermentation, the membrane adjusts to minimize the headspace volume, reducing methane losses from gas mixing. This dynamic volume adjustment resolves the contradiction between needing adaptability for phase transitions and minimizing methane losses.
Solution Approach 2:
The patent changes the volume parameter of the headspace by using a flexible membrane that responds to pressure changes. By controlling the membrane's position through pressure differential, the system optimizes the headspace volume at different process stages - larger during loading, minimized during fermentation to reduce methane losses from gas mixing.
2Loss of substance
If the headspace volume is reduced to minimize methane losses, then gas mixing losses are reduced, but the fermenter cannot accommodate biomass loading and gas production fluctuations
Solution Approach 1:
The flexible membrane creates a dynamic headspace volume that automatically adapts to process requirements. During biomass loading, the membrane moves to increase headspace volume to accommodate the incoming material. During fermentation, it moves to minimize volume and reduce methane losses. This dynamic behavior resolves the contradiction between minimizing losses and maintaining adaptability.
Solution Approach 2:
The flexible membrane serves multiple functions: it acts as a barrier to maintain gas tightness, a volume regulator to minimize methane losses, and a dynamic adapter to accommodate biomass loading and gas production fluctuations. This multi-functionality allows the system to achieve both loss reduction and operational flexibility.
3Loss of substance
If a flexible membrane is used to dynamically adjust fermenter volume, then methane losses are reduced, but the device complexity increases
Solution Approach 1:
The patent uses a flexible membrane (thin film) to create a simple yet effective volume adjustment mechanism. The membrane's flexibility allows it to respond passively to pressure changes caused by gas production and biomass loading, minimizing the need for complex active control systems while still achieving the goal of reducing methane losses.
Solution Approach 2:
The flexible membrane operates largely autonomously by responding to natural pressure differentials within the fermenter. Gas production and biomass loading automatically create pressure changes that move the membrane to the appropriate position, reducing the need for external control systems and simplifying the overall device complexity.
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
Significantly reduces methane losses and improves process efficiency by maintaining a flexible volume that compensates for gas production peaks and valleys, allowing for effective gas reuse and minimizing unnecessary volume usage.
Implementation Method 1
a flexible, gas-tight membrane (3) is used to reduce the volume of the fermenter (1)
Implementation Method 2
The entry of the biomass into the fermenter can be done by permanently installed loading devices or by mobile devices such as wheel loaders. In the further process, the fermenter is sealed gas-tight in order to produce methane-containing biogas during an anaerobic fermentation phase through the anaerobic fermentation of the biomass in the fermenter
Data Source
Figure 1
AI summary
Fermenting solid, stackable biomass (2) in a fermenter (1), comprises introducing the solid, stackable biomass into the fermenter, and fermenting in an anaerobic fermentation phase after a starting phase for producing methane containing biogas. The volume of the fermenter, preferably the volume of the head space of the fermenter is reduced during the transition of the starting phase in the fermentation phase before switching of gas stream discharged from the fermenter from the inlet of an exhaust system to the inlet of a biogas utilization system. Fermenting solid, stackable biomass (2) in a fermenter (1), comprises introducing the solid, stackable biomass into the fermenter, and fermenting in an anaerobic fermentation phase after a starting phase for producing methane containing biogas, where a shut-down phase is carried out after the fermentation phase, and a gas stream (5) is discharged from the fermenter. The volume of the fermenter, preferably the volume of the head space of the fermenter is reduced during the transition of the starting phase in the fermentation phase before switching of gas stream discharged from the fermenter from the inlet of an exhaust system to the inlet of a biogas utilization system, and/or during the transition of the fermentation in the shut-down phase before switching of gas stream discharged from the fermenter from the inlet of a biogas utilization system to the inlet of a lean-gas system or an exhaust system.