Biogas Upgradation System with Methane Recovery Unit
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Solution Overview
Problem
Existing biogas upgradation systems, particularly those using Pressure Swing Adsorption (PSA), suffer from high methane slippage, resulting in methane loss to the atmosphere and reduced recovery rates below 90%, which is environmentally harmful and financially inefficient.
Innovation Solution
A biogas upgradation system comprising a pre-treatment unit, drying unit, methane enrichment unit, and methane recovery unit, where the exhaust gas from these units is recirculated through a methane recovery unit with a buffer balloon and vacuum pressure swing adsorption, significantly reducing methane loss to less than 1% and enhancing methane recovery to over 99%.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Quantity of substance
If Pressure Swing Adsorption (PSA) is used for biogas upgradation, then carbon dioxide removal is achieved, but methane slippage increases resulting in methane loss to atmosphere
Solution Approach 1:
The patent applies the discarding and recovering principle by capturing the exhaust gas from the PSA unit (which was previously discarded) and redirecting it to the combustion chamber. This allows recovery of slippaged methane that would otherwise be lost to the atmosphere, converting it into useful heat energy for the drying process.
Solution Approach 2:
The patent converts the harmful effect of methane slippage into a beneficial outcome by using the slippaged methane in the exhaust gas as a fuel source. The combustion of this exhaust gas provides heat for the drying unit, transforming what was previously a loss into a useful energy source.
2Ease of operation
If exhaust gas is vented directly from PSA unit, then operational simplicity is maintained, but methane loss to atmosphere increases
Solution Approach 1:
The patent merges the exhaust gas stream from the PSA unit with the feed gas stream entering the drying unit by routing both to the combustion chamber. This integration creates a combined fuel source that utilizes otherwise wasted methane while maintaining operational simplicity through automated control.
Solution Approach 2:
The system implements a feedback mechanism where the exhaust gas from the PSA unit is fed back to the combustion chamber to provide heat for drying. This closed-loop approach ensures that methane that slipped through the PSA process is recovered and utilized, reducing overall methane loss while maintaining continuous operation.
3Quantity of substance
If water scrubbing is used for biogas upgradation, then carbon dioxide removal is achieved, but packing clogging occurs due to bacteria growth and elemental sulphur formation
Solution Approach 1:
The patent replaces the mechanical water scrubbing system with a Pressure Swing Adsorption system that uses adsorbent materials (molecular sieves or activated carbon) in a pressure swing process. This substitution eliminates the liquid water phase that causes bacterial growth and sulphur precipitation, thereby preventing packing clogging while maintaining CO2 removal efficiency.
Solution Approach 2:
The patent changes the operational parameters from liquid-phase absorption (water scrubbing) to gas-phase adsorption under pressure swing conditions. This parameter change from wet to dry processing eliminates the conditions that promote bacterial growth and elemental sulphur formation, ensuring long-term reliability of the adsorbent material.
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 a methane recovery rate greater than 99% while minimizing methane slippage, reducing environmental impact and increasing financial viability by recycling exhaust gases for further methane extraction.
Implementation Method 1
The dried biogas stream is passed through a molecular sieve bed to adsorb carbon dioxide therein and thereby separate the same from the dried biogas stream
Implementation Method 2
a methane enrichment unit (3), and a methane recovery unit (4). The pre-treatment unit (1) removes the hydrogen sulphide from the raw biogas feed and sends it to the drying unit (2) for moisture removal. Then, the dried biogas is directed to the methane enrichment unit (3) for extracting the methane by adsorbing the carbon dioxide into the molecular sieve.
Implementation Method 3
The cycle is repeated alternately for the first and second pairs of MPSA towers (31, 32; 49, 50) with the vacuum pump (42, 43) creating a pressure difference
Implementation Method 4
An exhaust stream from the drying unit (2) and the methane enrichment unit (3) is directed to the methane recovery unit (4) for extracting the maximum amount of methane. By re-circulating the exhaust gas into the methane recovery unit (4), the present invention significantly reduces甲烷 loss to less than 1%.
Data Source
AI summary
The present invention relates to a biogas upgradation system with reduced methane slippage by extracting maximum amount of methane and offering it in the product gas. The aforesaid system mainly comprises a pre-treatment unit (1), a drying unit (2), a methane enrichment unit (3), and a methane recovery unit (4). The pre-treatment unit (1) removes the hydrogen sulphide from the raw biogas feed and sends it to the drying unit (2) for moisture removal. Then, the dried biogas is directed to the methane enrichment unit (3) for extracting the methane by adsorbing the carbon dioxide into the molecular sieve. An exhaust stream from the drying unit (2) and the methane enrichment unit (3) is directed to the methane recovery unit (4) for extracting the maximum amount of methane. By re-circulating the exhaust gas into the methane recovery unit (4), the present invention significantly reduces methane loss to less than 1%.