Flue Gas CO2 Separation Using Physical Solvents and Alkali
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Existing methods for capturing carbon dioxide from flue gas, such as chemical absorption, physical absorption, and cryogenics, are inefficient and costly, particularly in large-scale facilities like power plants, and do not effectively adapt to various fuels and oxidants.
Innovation Solution
A method combining physical absorption into liquid solvents and reaction with alkalis, involving temperature and pressure adjustments of gaseous combustion products, followed by separation into carbon dioxide-rich and carbon dioxide-poor streams, with the latter expanded to perform work and capture carbon dioxide using solvents like water or methanol.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If chemical absorption into liquids (e.g., amines) is used to recover carbon dioxide from flue gas, then carbon capture can be achieved, but the process becomes costly and inefficient
Solution Approach 1:
The patent changes the fundamental parameter of the absorption mechanism from chemical (amines) to physical (water or methanol), operating at different temperature and pressure conditions to achieve efficient carbon dioxide capture without the complexity and cost of chemical absorption processes
Solution Approach 2:
The patent utilizes phase transitions of water or methanol between liquid and vapor states to facilitate carbon dioxide absorption and desorption cycles, enabling efficient carbon capture through physical changes rather than complex chemical reactions
2Productivity
If physical absorption into liquids (e.g., methanol) is used to recover carbon dioxide from flue gas, then carbon capture can be achieved, but operational costs remain high
Solution Approach 1:
The patent enables the absorption solvent (water or methanol) to self-regenerate through phase transitions and temperature/pressure changes, eliminating the need for energy-intensive regeneration processes and reducing operational costs while maintaining high carbon capture efficiency
Solution Approach 2:
The patent converts the typically harmful high-volume low-value flue gas stream into a beneficial source of concentrated carbon dioxide, while the heat and pressure conditions that would normally be wasted are utilized to drive the phase transitions and regeneration processes
3Quantity of substance
If existing carbon capture methods are applied to large-scale facilities like power plants, then carbon dioxide recovery is possible, but efficiency and cost-effectiveness deteriorate
Solution Approach 1:
The patent segments the flue gas treatment process into distinct absorption and desorption stages with phase transitions, allowing for efficient handling of large volumes of flue gas at power plant scale while maintaining high carbon dioxide recovery efficiency through modular process design
4Quantity of substance
If conventional carbon capture methods are used, then carbon dioxide separation is achieved, but adaptability to various fuels and oxidants is limited
Solution Approach 1:
The patent employs a universal physical absorption mechanism using water or methanol that functions effectively across different fuel types (coal, natural gas, biomass) and oxidants (air, oxygen-enriched air), as the phase transition-based process is independent of the specific combustion chemistry
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
Enhances carbon capture efficiency and adaptability to various fuels and oxidants, reducing operational costs and improving overall process efficiency.
Implementation Method 1
This invention employs two methods: (1) physical absorption into liquid
Implementation Method 2
This invention employs two methods: (2) reaction with alkalis
Implementation Method 3
The temperature and/or pressure of these gaseous combustion products is then adjusted to a level suitable for separation, such as by cooling the products to a suitable temperature
Data Source
AI summary
Flue gas is compressed to high pressures, which raises the partial pressure of carbon dioxide thus facilitating its absorption into physical solvents (e.g., water, salt solutions, methanol). When added onto an existing CO2-producing process, the compression is performed using multiple stages with intercooling. After the high-pressure carbon dioxide dissolves into the physical solvent, it flows through a series of pressure letdowns using turbines that allow the dissolved carbon dioxide to evolve from the solvent. Through a series of multiple compression stages, the evolved gas is compressed for transport, utilization, or storage. The flue gas that has been scrubbed of carbon dioxide flows through a series of expanders with interheating supplied from waste heat, or the heat of compression. The process is enhanced by employing alkalis that chemically react with acid gases, such as carbon dioxide. These same CO2-capture processes can be integrated into processes that produce shaft and/or electrical power.