Biogas Membrane Permeation with Dynamic Suction Pressure Control
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Solution Overview
Problem
Existing technologies face challenges in achieving a consistent methane concentration in biogas, which is essential for regular operation of equipment using biomethane.
Innovation Solution
The proposed installation uses a multi-stage membrane permeation process with specific membrane selectivity and recycling configurations, along with pressure adjustment mechanisms to maintain consistent methane concentration.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If a multi-stage membrane permeation process is used to separate CO2 from biogas, then the purity of methane is improved, but the complexity of the device increases
Solution Approach 1:
The patent divides the CO2 separation process into multiple membrane stages (first membrane unit, second membrane unit, third membrane unit) with each stage performing a specific separation function. This segmentation allows achieving high methane purity through progressive separation while managing the complexity by organizing each stage with dedicated components and control mechanisms.
Solution Approach 2:
The patent implements recycling loops where the permeate from the second membrane unit is recycled to the feed gas stream, and the retentate from the third membrane unit is recycled to the compressor inlet. This recovering approach improves methane purity by reprocessing streams that contain valuable methane, while the complexity is managed through automated control systems that regulate the recycling flows.
2Reliability
If the suction pressure of the second permeate is adjusted to maintain consistent methane concentration, then the reliability of biomethane production is improved, but the energy consumption increases
Solution Approach 1:
The patent implements a feedback control system where the suction pressure of the second permeate is continuously monitored and automatically adjusted by the compressor B to maintain a set value. This feedback mechanism ensures consistent methane concentration in the biomethane product, while the automated control optimizes energy consumption by adjusting compressor operation based on actual process conditions rather than maintaining constant high energy input.
Solution Approach 2:
The patent employs dynamic pressure adjustment in the membrane separation process, where the suction pressure of the second permeate is varied to optimize separation efficiency and maintain consistent methane concentration. This dynamic operation allows the system to adapt to changing feed gas conditions, improving reliability while avoiding the excessive energy consumption associated with static high-pressure operation.
3Productivity
If membrane technology is used to separate CO2 from biogas, then the purification efficiency is improved, but the methane losses in residual gas increase
Solution Approach 1:
The patent recycles the retentate stream from the third membrane unit back to the compressor inlet, where it is mixed with the fresh feed gas and reprocessed. This recovering approach minimizes methane losses by ensuring that methane-containing streams are not discarded but rather returned to the separation process for further purification and utilization.
Solution Approach 2:
The patent implements continuous recycling loops for both permeate and retentate streams, ensuring that valuable methane is continuously reprocessed rather than being lost in intermittent batch operations. This continuous action maintains high separation efficiency while minimizing methane losses through persistent recovery and reprocessing of methane-containing streams.
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
This solution effectively produces a methane current with a consistent concentration, minimizing methane losses and reducing purification costs, thereby ensuring reliable operation of biomethane-using equipment.
Implementation Method 1
System and method for treating a gaseous current by membrane permeation with adjustment of the suction pressure of the second permeate
Implementation Method 2
with each membrane separation unit comprising at least one membrane more permeable to carbon dioxide than to methane
Implementation Method 3
a compressor A for compressing the feed gas stream
Implementation Method 4
at least one compressor B allowing the suction of the second permeate and the adjustment of the suction pressure of the second permeate
Data Source
Figure 1
AI summary
Installation for the treatment by membrane permeation of a feed gas stream comprising at least methane and carbon dioxide, comprising: - a compressor A for compressing the feed gas stream, - a first membrane separation unit capable of receiving the gas stream from the compressor and providing a first permeate and a first retentate, - a second membrane separation unit capable of receiving the first retentate and providing a second permeate and a second retentate, - a third membrane separation unit capable of receiving the first permeate and providing a third permeate and a third retentate, - at least one means for measuring the suction pressure of the second permeate from the second membrane unit,and - at least one compressor B enabling the aspiration of the second permeate and the adjustment of the aspiration pressure of the second permeate according to the measured aspiration pressure before recycling the second permeate into the feed gas stream downstream of compressor A, with each membrane separation unit comprising at least one membrane more permeable to carbon dioxide than to methane.