Vacuum Pressure Swing Adsorption for CO2 Concentration
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Solution Overview
Problem
Existing methods for producing dry ice from carbon dioxide gas require large facilities and have low energy efficiency due to the need for extensive raw material usage and energy consumption, particularly when dealing with low concentrations of carbon dioxide gas and the requirement for heat sources and purge steps in thermal-pressure swing adsorption processes.
Innovation Solution
A method involving vacuum regeneration pressure swing adsorption in multiple stages to concentrate carbon dioxide gas, eliminating the need for purge steps and utilizing membrane separation to achieve high concentrations of carbon dioxide gas, followed by liquefaction and solidification to produce dry ice.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If carbon dioxide gas is directly turned into dry ice by cooling to a solidification temperature, then the process is simple, but a large amount of exhaust gas is required and large facilities are needed
Solution Approach 1:
The patent divides the concentration process into multiple stages using multiple adsorption towers. The first adsorption tower concentrates CO2 to an intermediate concentration, and the second adsorption tower further concentrates it to high concentration. This segmentation allows each tower to be smaller while achieving the overall concentration goal, reducing total facility size compared to a single large tower.
Solution Approach 2:
The patent changes the concentration parameter progressively through multiple stages. The first tower achieves intermediate concentration (e.g., 30-50 vol%), and the second tower achieves high concentration (e.g., 90 vol% or more). This staged parameter change allows smaller facility size while maintaining process simplicity.
2Quantity of substance
If thermal-pressure swing adsorption is used to concentrate carbon dioxide gas, then concentration is achieved, but it requires heating and cooling steps that increase energy consumption and time
Solution Approach 1:
The patent extracts the heating step from the concentration process by using pressure swing adsorption instead of thermal swing adsorption. The regeneration is achieved through pressure changes alone, eliminating the need for external heating and cooling, thus reducing energy consumption while maintaining effective CO2 concentration.
Solution Approach 2:
The patent replaces the thermal field (heating/cooling) with a mechanical field (pressure changes). Pressure swing adsorption uses compression and expansion cycles to achieve adsorption and regeneration, substituting thermal energy with mechanical energy, which reduces overall energy consumption.
3Use of energy by moving object
If pressure swing adsorption is used to concentrate carbon dioxide gas, then energy consumption is reduced, but a purge step requiring a blower increases facility size and energy use
Solution Approach 1:
The patent merges the purge function into the existing pressure swing cycle by using the product gas itself for regeneration. The high-pressure product gas from one tower serves to regenerate the other tower, eliminating the need for a separate blower and purge facility, thus reducing both facility size and energy consumption.
Solution Approach 2:
The system uses its own product gas to perform the regeneration function. The concentrated CO2 gas from the first tower is used to regenerate the second tower, and vice versa. This self-service approach eliminates external purge equipment and reduces overall facility size while maintaining low energy consumption.
4Volume of stationary object
If a single adsorption tower is used for carbon dioxide concentration, then the facility is compact, but the amount of gas treated per tower increases and efficiency decreases
Solution Approach 1:
The patent segments the gas treatment function across multiple towers operating in parallel. While each tower is compact, the system as a whole achieves high productivity by having multiple towers work simultaneously in alternating cycles. This segmentation allows compact individual units to achieve high overall efficiency.
Solution Approach 2:
The patent ensures continuous operation by having multiple towers in different phases of the adsorption-regeneration cycle simultaneously. While one tower is adsorbing, another is regenerating, ensuring uninterrupted CO2 concentration and maximizing gas treatment efficiency without requiring large individual tower sizes.
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 reduces energy consumption and facilitates the production of high-concentration purified carbon dioxide gas and dry ice, minimizing facility size and energy requirements while enhancing energy efficiency.
Implementation Method 1
a first concentration step in which an intermediate gas having a higher concentration of carbon dioxide gas than a target gas is produced by vacuum regeneration pressure swing adsorption using a first adsorption tower that adsorbs carbon dioxide gas from the target gas
Implementation Method 2
a second concentration step in which the purified gas having an even higher concentration of carbon dioxide gas than the intermediate gas is produced by vacuum regeneration pressure swing adsorption using a second adsorption tower that adsorbs carbon dioxide gas from the intermediate gas or membrane separation
Implementation Method 3
a liquefying step in which the purified gas is cooled to produce liquefied carbon dioxide
Implementation Method 4
a dry ice production step in which the liquefied carbon dioxide is solidified to obtain dry ice
Data Source
AI summary
A method for producing a purified gas containing carbon dioxide gas, comprising: a first concentration step in which an intermediate gas having a higher concentration of carbon dioxide gas than a target gas is produced by vacuum regeneration pressure swing adsorption using a first adsorption tower that adsorbs carbon dioxide gas from the target gas containing carbon dioxide gas; and a second concentration step in which the purified gas having an even higher concentration of carbon dioxide gas than the intermediate gas is produced by vacuum regeneration pressure swing adsorption using a second adsorption tower that adsorbs carbon dioxide gas from the intermediate gas or membrane separation.