Expandable Membrane Lagoon Cover for Methane Containment
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Solution Overview
Problem
Anaerobic digestion systems are often exposed to natural elements, making operation and monitoring difficult, and open-slurry lagoons result in high fugitive methane emissions, leading to environmental and operational challenges.
Innovation Solution
A cover system for lagoons using an expandable membrane with stretchable and restraining members, along with a skirt and gas processing unit, to contain methane, manage rainwater, and minimize corrosion, while allowing for monitoring and retrofitting existing lagoons.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of operation
If an open-slurry lagoon is used, then operation and monitoring are simple, but fugitive methane emissions are high
Solution Approach 1:
The patent employs a flexible membrane cover that can be deployed over the slurry lagoon to contain methane emissions. The membrane is held in place by weights distributed around the perimeter, creating a sealed environment that prevents fugitive emissions while maintaining operational simplicity. This approach directly addresses the contradiction by providing emission containment without requiring complex active control systems.
2Object-generated harmful factors
If a covered lagoon system is installed, then methane capture efficiency increases, but device complexity increases
Solution Approach 1:
The membrane cover system is designed to be self-regulating through the distribution of weights around the perimeter. The weights automatically adjust to maintain membrane tension and seal integrity without requiring active control mechanisms. This self-service approach reduces system complexity while maintaining high methane capture efficiency, as the system autonomously adapts to varying gas pressures and environmental conditions.
3Volume of stationary object
If the membrane is allowed to expand freely, then gas containment volume increases, but structural stability decreases
Solution Approach 1:
The patent utilizes weights positioned around the perimeter of the membrane cover to provide counterbalancing force against the internal gas pressure. These weights prevent the membrane from expanding uncontrollably while still allowing sufficient volume for gas containment. The counterweight mechanism maintains structural stability by continuously opposing the outward force of trapped gases, preventing membrane rupture or excessive deformation.
4Strength
If stretchable members are used to compress the membrane, then membrane tension is maintained, but manufacturing complexity increases
Solution Approach 1:
The stretchable members are designed to dynamically adjust their tension based on varying gas pressures and membrane expansion. This dynamic characteristic allows the system to maintain optimal membrane tension across different operating conditions without requiring complex pre-engineering for all possible scenarios. The members can elongate and contract as needed, providing adaptive tensioning that simplifies manufacturing compared to rigid, pre-set tensioning systems.
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 effectively captures 80-95% of fugitive methane, reduces nitrogen loss, minimizes corrosion, and provides operational benefits such as reduced energy demands and fertilizer needs, with a long-lasting and cost-effective solution for small to mid-sized farms.
Implementation Method 1
an expandable membrane with stretchable and restraining members
Implementation Method 2
Anaerobic digestion is a process that can be used to convert a wide range of biomass materials into useable gas, such as a gas comprising mostly methane and carbon dioxide
Data Source
AI summary
A cover for a lagoon is provided. The cover includes an expandable membrane; a plurality of stretchable members coupled to the expandable membrane and configured to compress the expandable membrane; and a plurality of restraining members coupled to the expandable membrane and configured to limit expansion of the expandable membrane.