Heated Membrane Separation for Methane Recovery From Non-Condensable Gas
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Solution Overview
Problem
Existing biogas upgrading technologies struggle to efficiently separate non-condensable gases, particularly those containing significant fractions of methane and carbon dioxide, leading to inefficient recovery and potential environmental harm from venting these gases to the atmosphere.
Innovation Solution
A method involving pressure reduction, heating, and membrane separation is employed to separate non-condensable gases, utilizing a process stream at elevated pressures and temperatures to enhance methane and carbon dioxide recovery, with optional venting and membrane modules for selective permeation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If three-stage membrane separation is used for biomethane production, then CO2 removal efficiency is improved, but the non-condensable gas stream contains significant methane that must be vented
Solution Approach 1:
The patent changes the temperature parameter of the non-condensable gas stream from typical low temperatures to a specific temperature range of 10-50°C. This temperature optimization enhances the membrane separation performance, allowing for more effective methane recovery while maintaining CO2 removal efficiency. The temperature adjustment modifies the gas properties and membrane permeability to achieve better separation outcomes.
Solution Approach 2:
The patent applies preliminary heating of the non-condensable gas stream before it enters the membrane separation unit. This preliminary action prepares the gas stream by achieving optimal temperature conditions that maximize methane permeation through the membrane, thereby reducing methane loss before the actual separation process begins.
2Ease of operation
If non-condensable gas is vented to atmosphere, then system operation is simplified, but environmental harm increases
Solution Approach 1:
The patent extracts valuable methane from the non-condensable gas stream that would otherwise be vented to the atmosphere. By introducing a membrane separation unit specifically targeted at recovering methane, the system removes this harmful emission source while simultaneously capturing the greenhouse gas for potential reuse or controlled disposal, thus addressing both environmental concerns and operational complexity.
Solution Approach 2:
Instead of simply discarding the non-condensable gas stream to the atmosphere, the patent implements a recovery system using membrane separation. This allows the valuable methane component to be recovered and separated from the stream, converting what would be a harmful emission into a recoverable resource, thereby reducing atmospheric emissions while maintaining operational feasibility.
3Device complexity
If two-stage membrane upgrading is used, then process complexity is reduced, but methane slip increases significantly
Solution Approach 1:
The patent optimizes the temperature parameter of the membrane separation process to enhance methane recovery. By operating at elevated temperatures of 10-50°C, the membrane system achieves improved methane selectivity and permeation, allowing for effective methane slip reduction even in simplified two-stage configurations without requiring complex multi-stage 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 method effectively recovers valuable methane and carbon dioxide from non-condensable gases, improving biogas upgrading efficiency and reducing atmospheric emissions, while maintaining low power consumption and operational costs.
Implementation Method 1
subjecting at least part of the process stream to membrane separation to provide a methane rich retentate stream and a carbon dioxide rich permeate stream
Implementation Method 2
wherein the process stream is at a pressure of at least 3 barg when subjected to the membrane separation and wherein the retentate side of the membrane is at a pressure of at least 3 barg and wherein there is a pressure loss at the permeate side of the membrane
Implementation Method 3
heating of the process stream to a temperature of at least 15 degrees Celsius
Implementation Method 4
reducing the pressure of the process stream with at least 1 barg
Data Source
Figure 1
AI summary
The invention relates to a method for the separation of a non-condensable gas, comprising the steps of providing a process stream comprising a non-condensable gas, wherein the process stream is at a predetermined pressure and temperature, heating of the process stream and optionally releasing at least part of the process stream in particular to the atmosphere and/or subjecting at least part of the process stream to membrane separation to provide a methane rich retentate stream and a carbon dioxide rich permeate stream.