Pressure Swing Adsorption Yield via High-Pressure Feed and Recycle
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Solution Overview
Problem
The existing pressure swing adsorption (PSA) process for gas purification faces a yield limit due to the requirement of product gas for regenerating the adsorption mass, leading to a loss of product gas and saturation of the adsorbent at high pressures, which restricts the purity and efficiency of fuel gas separation.
Innovation Solution
Increasing the pressure of the second gas mixture prior to introduction into the PSA vessel, allowing the residual gas mixture to be recycled back to the first separation device, thereby avoiding adsorbent saturation and enhancing the yield of the separation process by increasing the pressure by a factor of at least 10 to 50 times the initial pressure.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If the pressure of the gas mixture introduced into the PSA device is increased to improve separation efficiency, then the productivity increases, but the adsorbent becomes saturated which reduces the purity of the product gas
Solution Approach 1:
The separation process is divided into two distinct stages: a first separation step that removes the majority of pollutant gas B, and a second PSA step that achieves final high purity. This segmentation allows each stage to operate under optimized conditions, with the first step handling bulk removal at higher pressures and the second step achieving trace purification
Solution Approach 2:
The first separation step performs preliminary removal of the majority of pollutant gas B before the gas mixture enters the PSA device. This preliminary action reduces the pollutant concentration to levels that prevent adsorbent saturation in the subsequent PSA step, enabling the PSA process to operate effectively at high pressures without sacrificing purity
2Manufacturing precision
If product gas is used to regenerate the adsorption mass in the PSA process to maintain purity, then the purity is maintained, but the yield of product gas is reduced due to the loss of product gas during regeneration
Solution Approach 1:
The process changes the pressure parameter dramatically, introducing the gas mixture at very high pressure (10-50 times atmospheric pressure) into the PSA device. This parameter change allows the use of low-pressure purge gas for regeneration without requiring large quantities of product gas, as the high pressure differential enables efficient desorption during the depressurization phase
Solution Approach 2:
The purge gas that exits the PSA device during regeneration is not discarded but is instead fed back to the first separation step. This feedback loop allows the purge gas to be reused for its intended purpose of regenerating the adsorbent in the first separation step, eliminating the need to consume additional product gas for regeneration and thereby increasing the overall yield
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 significantly increases the yield of the separation process, achieving high purity of fuel gases like hydrogen and methane while maintaining the purity demands, with yields up to 1500 compared to typical yields of 8-20 in conventional PSA processes.
Implementation Method 1
use is made of an adsorption mass of a selective adsorbent, wherein the adsorption strength for the first gas (A) is lower than the adsorption strength for the second gas (B). In that way the second gas is adsorbed to the adsorption mass in the respective vessel in question at a relatively high pressure
Implementation Method 2
the value of the pressure (p1) of the second gas mixture (A/B)2 is increased to a value p2 (p2 >p1) prior to introducing it into the at least one vessel
Data Source
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AI summary
The invention relates to the purification of a gas that can be used as fuel starting from a crude gas mixture. A high purity level in fuel is of great importance to the combustion efficiency and moreover contributes to the life span of the constituent parts of machines in which the fuels are being used. The invention thus relates to a method for purifying a gas that can be used as fuel, by separating a first gas mixture (A/B)1 of a first gas (A) that can be used as fuel and at least a second gas (B) into a first gas (A) and at least a second gas (B).