Method and system for separating a gas mixture
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Solution Overview
Problem
Current pressure swing adsorption (PSA) methods face limitations in achieving high concentrations of strongly adsorbable components, such as carbon dioxide, due to constraints in split factors, circulation rates, and the requirement for minimum weakly adsorbable components, which restrict the arbitrary connection of PSA units and efficiency in separating gas mixtures.
Innovation Solution
A method and system that involves forming a feed flow from a gas mixture, separating it using PSA, and then subjecting the low-pressure extraction flow to compression and thermal separation, where partial condensation and expansion generate a condensate share used to enhance separation efficiency, allowing for the targeted enrichment of strongly adsorbable components through counterflow cooling and recirculation, mimicking a heat pump principle.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If PSA units are connected in series to increase concentration of strongly adsorbable components, then concentration improves, but the system requires minimum weakly adsorbable components which limits arbitrary connection of PSA units
Solution Approach 1:
The invention changes the operating parameters by introducing a circulation mode where the low-pressure extraction flow is compressed and mixed with the inlet flow. This parameter change allows the system to operate without the minimum weakly adsorbable component constraint, enabling arbitrary connection of PSA units while achieving high concentrations of strongly adsorbable components.
Solution Approach 2:
The invention implements a feedback mechanism by circulating a portion of the low-pressure extraction flow back to the inlet after compression. This feedback loop allows the system to maintain stable operation and achieve high concentrations of strongly adsorbable components without being limited by the minimum weakly adsorbable component requirement.
2Productivity
If circulation rate is increased to improve separation efficiency, then separation efficiency improves, but yield of weakly adsorbable components decreases
Solution Approach 1:
The invention changes the parameter of circulation by compressing the low-pressure extraction flow and mixing it with the inlet flow in a controlled manner. This parameter change allows the system to achieve high separation efficiency while maintaining acceptable yield of weakly adsorbable components through optimized mixing ratios.
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 enables improved concentration of strongly adsorbable components, even at high circulation rates, with increased yield of weakly adsorbable components and selective discharge of strongly adsorbable components, overcoming previous limitations in PSA unit connections and separation efficiencies.
Implementation Method 1
Adsorption takes place during PSA typically using porous adsorbents. The adsorbed shares of the adsorbable components depend in particular on the pressure of the inlet flow supplied to the PSA, i.e. the adsorption pressure, and on the selectivity of the adsorbent.
Implementation Method 2
at least a share of the low-pressure extraction flow 3' is subjected to compression 11
Implementation Method 3
separating at least some of the higher-boiling components, which typically adsorb more strongly in the PSA at the same time, in this thermal separation
Data Source
AI summary
Separating a starting gas mixture using pressure swing adsorption. In this, at least part of a low-pressure extraction flow from the pressure swing adsorption is subjected to a thermal separation, wherein a return fraction is formed in the thermal separation which is returned to the pressure swing adsorption separation. In the thermal separation, counterflow cooling takes place to obtain a two-phase mixture, wherein at least part of the two-phase mixture is subjected to phase separation to obtain a gas phase and a condensate. At least a part of the gas phase is used to form the return fraction, and counterflow cooling is carried out using at least a part of the gas phase and at least a part of one or more fluid flows which are formed by expansion of at least a part of the liquid phase.