Two-Pressure CO2 Vaporization for Lower-Energy Flue Gas Separation
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Solution Overview
Problem
Current methods for carbon dioxide recovery from oxy-combustion power plants are inefficient and costly due to dilution by nitrogen, requiring high power input and capital expenditure, and existing processes for purification are not cost-effective in minimizing power consumption and maximizing CO2 concentration.
Innovation Solution
A method involving the separation of flue gas into multiple streams, followed by warming and vaporization, and the use of two expanders to recover energy efficiently, reducing the need for expensive equipment and minimizing power consumption by utilizing heat exchangers and refrigeration to achieve high CO2 concentrations.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Quantity of substance
If traditional amine contact tower is used to scrub out carbon dioxide from flue gas, then carbon dioxide can be recovered, but high heat input is required to regenerate the amine which reduces cost effectiveness
Solution Approach 1:
The invention changes the operating parameters from traditional single-pressure amine scrubbing to a two-pressure system where absorption occurs at high pressure and stripping occurs at low pressure. This parameter change allows the process to operate without high heat input for regeneration, as the pressure differential drives the CO2 release during stripping rather than thermal energy
Solution Approach 2:
The invention utilizes phase transitions of carbon dioxide between dissolved state in amine solution during absorption and gaseous state during stripping. By controlling pressure changes between two different pressures, the CO2 is released from the amine solution during the stripping stage without requiring high heat input, leveraging the pressure-dependent solubility and phase behavior of CO2
2Quantity of substance
If air combustion is used in power plants, then complete combustion is achieved, but carbon dioxide is diluted by nitrogen which increases recovery cost and difficulty
Solution Approach 1:
The invention extracts carbon dioxide from the diluted flue gas stream by using an amine solution that selectively absorbs CO2 at high pressure. The two-pressure system enables efficient separation of CO2 from the nitrogen-diluted flue gas, concentrating the CO2 in the rich amine stream that is then processed in the stripping column
Solution Approach 2:
The amine solution acts as an intermediary medium that facilitates the transfer of carbon dioxide from the gas phase to liquid phase during absorption, and then releases it during stripping. This intermediary enables efficient CO2 separation from the diluted flue gas without requiring direct heating of the gas stream
3Quantity of substance
If oxy-combustion process is used to achieve high carbon dioxide concentration, then flue gas contains 75-95 mol percent carbon dioxide, but high purity oxygen supply requires significant capital expenditure and power input
Solution Approach 1:
The invention applies partial action by using a two-pressure amine scrubbing system that can effectively concentrate CO2 from flue gas without requiring complete oxygen replacement of air. The process achieves sufficient CO2 concentration for recovery applications by optimizing the absorption and stripping operations at different pressures, rather than requiring full oxy-combustion infrastructure
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 enhances the cost-effectiveness and efficiency of carbon dioxide recovery by reducing energy consumption and capital expenditure, achieving higher CO2 concentrations while minimizing the use of costly equipment and maintaining efficient steam production.
Implementation Method 1
The first liquid stream is warmed and vaporized
Implementation Method 2
The second liquid stream is warmed and vaporized
Implementation Method 3
utilizing heat exchangers and refrigeration to achieve high CO2 concentrations
Data Source
AI summary
An improved process for the separation of carbon dioxide from the flue gas of an oxy-combustion power plant is provided. At least a first product stream and a second product stream are separated from a flue gas stream, wherein the pressure of the first product stream and the pressure of the second product stream are different. The first product stream is warmed and vaporized. The second product stream is then warmed and vaporized.