Cryogenic Methane Separation with Adsorption and Distillation
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Solution Overview
Problem
Current methods for purifying methane-rich flows from organic sources are ineffective in removing impurities like carbon dioxide, oxygen, and nitrogen, as they often result in products with higher concentrations of these impurities than desired, typically exceeding 2%.
Innovation Solution
A cryogenic separation method involving an adsorption purification unit followed by distillation, where the carbon dioxide-lean flow is cooled and sent to a distillation column, producing a methane-rich flow while regenerating the purification unit with vaporized methane, and utilizing external liquid nitrogen for cooling to maintain low impurity levels.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If conventional purification methods are used to remove impurities from methane-rich flows, then the purification process is simpler, but the product contains more than 2% carbon dioxide and oxygen/nitrogen impurities
Solution Approach 1:
The purification process is divided into two distinct stages: adsorption purification to remove carbon dioxide, followed by cryogenic distillation to remove oxygen and nitrogen. This segmentation allows each unit to target specific impurities, achieving high methane purity (less than 2% total impurities) while making the overall process manageable through modular design
Solution Approach 2:
The process transforms the physical state of the methane-rich flow from gaseous to liquid through cooling, enabling separation by distillation. By changing temperature parameters to cryogenic conditions, the method achieves high purification precision that conventional methods cannot attain
2Reliability
If the purification unit is regenerated using external resources, then regeneration effectiveness is improved, but energy consumption and operational complexity increase
Solution Approach 1:
The purification unit is regenerated using vaporized methane from the distillation column itself, rather than external resources. The methane-rich vapor from the distillation process flows back through the adsorption bed, desorbing accumulated carbon dioxide and regenerating the adsorbent in place. This self-service approach ensures reliable continuous operation while minimizing external energy input and operational 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
This method achieves a methane-rich product with less than 2% carbon dioxide and oxygen/nitrogen, exceeding 98% methane purity, effectively addressing the impurity removal limitations of existing technologies.
Implementation Method 1
the flow is sent to an adsorption purification unit for producing a flow lean in carbon dioxide relative to the feed flow
Implementation Method 2
at least part of the carbon dioxide-lean flow is cooled so as to produce a cooled flow
Implementation Method 3
at least part of the cooled flow is sent to the distillation column, a flow rich in methane relative to the feed flow is withdrawn from the distillation column
Implementation Method 4
the purification unit is regenerated by at least part of the vaporized methane-rich liquid
Implementation Method 5
liquid nitrogen vaporizes by heat exchange with the carbon dioxide-lean flow
Data Source
AI summary
A method and device for the cryogenic separation of a methane-rich flow is provided.