Method and apparatus for separating a mixture of hydrogen and carbon dioxide
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Current separation processes for hydrogen and carbon dioxide mixtures, particularly those post-adsorption, face inefficiencies and instability due to varying load conditions, leading to suboptimal recovery rates and potential turbine instability.
Innovation Solution
A process involving compression, optional drying, partial condensation/distillation, and permeation through a membrane system, with turbine expansion and recycling of residues to maintain stable operation and enhance separation efficiency, particularly by regulating flow rates and utilizing multiple membrane units for improved CO2 and hydrogen recovery.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the residue from turbine expansion is not recycled to the compressor, then the system complexity is reduced, but the turbine operation becomes unstable and performance losses increase at reduced loads
Solution Approach 1:
The patent implements a feedback mechanism where the residue stream from turbine expansion is recycled back to the compressor inlet. This closed-loop configuration allows the system to maintain stable turbine operation by ensuring sufficient flow through the turbine, particularly at reduced loads. The feedback loop compensates for variations in process conditions and maintains reliable operation.
Solution Approach 2:
The residue stream serves multiple functions: it provides flow to maintain turbine stability, acts as a recycle stream to optimize separation performance, and can be adjusted in flow rate to adapt to different operating conditions. This multi-functional use of the residue stream resolves the contradiction between simplicity and reliability.
2Productivity
If multiple membrane units are used in series, then the separation efficiency and recovery rates improve, but the device complexity and capital cost increase
Solution Approach 1:
The patent divides the membrane separation process into multiple units arranged in series, with each unit handling a portion of the separation task. This segmentation allows the system to achieve high recovery rates (97% CO2, 99% hydrogen) by progressively removing components through each membrane unit, while maintaining manageable complexity through modular configuration.
Solution Approach 2:
The membrane units are configured in a nested arrangement where the output of one unit becomes the input of the next, creating a cascading separation system. This nesting approach maximizes the utilization of each membrane unit's separation capacity and achieves high overall recovery rates without requiring excessively large single units.
3Use of energy by moving object
If the residue flow rate through the turbine is reduced, then the energy consumption decreases, but the turbine operation becomes unstable
Solution Approach 1:
The patent implements dynamic control of the residue recycle flow rate to the compressor, allowing the system to adapt to different operating conditions. By dynamically adjusting the recycle ratio, the system maintains sufficient turbine inlet flow for stable operation while optimizing energy consumption based on actual process requirements and load conditions.
Solution Approach 2:
The system changes the flow rate parameter of the residue stream based on operating conditions. By adjusting this parameter, the system maintains turbine stability across varying loads while optimizing energy consumption, resolving the contradiction between energy efficiency and operational reliability.
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 approach achieves over 97% CO2 and 99% hydrogen recovery, reducing performance losses and maintaining efficiency even at reduced loads, while stabilizing turbine operation and minimizing energy consumption.
Implementation Method 1
Separating by permeation in a membrane system the first stream depleted in CO2 to form at least one permeate of the membrane system enriched in hydrogen and carbon dioxide and depleted in the at least one component compared to the first stream depleted in CO2
Implementation Method 2
Expansion of at least a portion of the residue in at least one turbine characterized by recycling at least a portion of the residue from the at least one turbine to the compressor
Implementation Method 3
Compressing the mixture from a first pressure to a second pressure to form a compressed mixture
Implementation Method 4
Separating the compressed and optionally dried mixture at the second pressure or at a third pressure higher than the second pressure by partial condensation and/or distillation generating at least one product enriched in CO2 and a first stream depleted in CO2
Implementation Method 5
Separating the compressed and optionally dried mixture at the second pressure or at a third pressure higher than the second pressure by partial condensation and/or distillation generating at least one product enriched in CO2
Data Source
Figure 1~3
Figure 4~5
AI summary
In a process for separating a mixture containing hydrogen and carbon dioxide, the mixture (7) is compressed (9) to form a compressed mixture, the compressed mixture is separated by partial condensation and/or distillation generating a first CO2-depleted stream (25), the first CO2-depleted stream (25) is separated by permeation in a membrane system (27) to form a residue (35) of the membrane system depleted in hydrogen and carbon dioxide, and part of the residue is recycled after expansion in the compressor (9) to be compressed there.