Fluidized Bed CO2 Capture with Internal Cooling
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Solution Overview
Problem
Current carbon dioxide capture processes from gas streams, particularly flue gas, face inefficiencies due to high energy consumption and adverse effects of moisture on adsorbents, as well as high regeneration energy requirements.
Innovation Solution
A counter current multistage fluidized bed system using regenerable solid adsorbents with 15-75% organic amine compounds, where the gas stream is contacted with adsorbent particles in an adsorption zone with internal cooling, and the enriched adsorbents are regenerated using steam in a desorption zone, allowing for efficient CO2 capture and heat integration.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Quantity of substance
If liquid absorption processes are used for CO2 removal, then CO2 can be effectively removed from gas streams, but high energy consumption is required in the stripper unit to recover the absorbent
Solution Approach 1:
The patent replaces liquid absorption processes with solid adsorption processes. Solid adsorbent particles are used instead of liquid absorbents, eliminating the need for a high-energy stripper unit. The solid adsorbents can be directly regenerated by heating or pressure reduction, significantly reducing the energy required for absorbent recovery while maintaining effective CO2 removal from gas streams.
Solution Approach 2:
The patent changes the physical state parameter from liquid to solid phase for the absorption medium. This parameter change fundamentally alters the regeneration process, allowing for lower energy consumption during desorption. The solid adsorbent particles can be regenerated at lower temperatures and with simpler equipment compared to liquid absorbent systems.
2Adaptability or versatility
If moisture is present in the gas stream, then realistic flue gas conditions are maintained, but CO2 uptake of adsorbents is adversely affected
Solution Approach 1:
The patent employs composite adsorbent materials that combine multiple components with complementary properties. These composite structures include hydrophobic components that resist moisture adsorption while maintaining CO2 adsorption capacity. The composite nature allows the material to function effectively in moist flue gas conditions without significant loss of CO2 uptake performance.
Solution Approach 2:
The patent modifies specific local properties of the adsorbent material to create moisture-resistant zones or surfaces. By introducing hydrophobic coatings or modifying surface chemistry at specific locations on the adsorbent particles, the material maintains CO2 adsorption capability while becoming tolerant to the presence of moisture in the gas stream.
3Quantity of substance
If high CO2 capture efficiencies are achieved, then more CO2 is removed from the gas stream, but high solid recirculation rates and high flows of stripping gas are required leading to high regeneration energy
Solution Approach 1:
The patent extracts and removes the energy-intensive stripping gas flow requirement from the system. By using solid adsorbent particles that can be regenerated through simpler heating or pressure reduction processes, the system eliminates the need for high flows of stripping gas, thereby reducing regeneration energy consumption while maintaining high CO2 capture efficiency.
Solution Approach 2:
The patent changes the regeneration mechanism parameters from chemical reaction-based (requiring stripping gas) to physical adsorption-based (allowing simple heating or pressure reduction). This parameter change enables high CO2 capture efficiency to be achieved without the penalty of high regeneration energy requirements associated with stripping gas flows.
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 process achieves a high CO2 capture efficiency of at least 80%, effectively reducing CO2 levels in gas streams to less than 20% and minimizing adsorbent lump formation, while optimizing heat integration and selectivity for CO2 capture.
Implementation Method 1
contacting the gas stream with solid adsorbent particles in an adsorption zone
Implementation Method 2
the adsorption zone has at least one internal cooling means in each of the beds of fluidized solid absorbent particles
Implementation Method 3
regenerating at least a part of the carbon dioxide enriched solid absorbent particles obtained in step (d) in a desorption zone, wherein the desorption zone has at least two beds of fluidized solid adsorbent particles... and wherein the stripping gas comprises at least 50 volume% steam
Implementation Method 4
heating at least a part of the carbon dioxide enriched solid adsorbent particles in the riser zone (I), optionally by means of direct or indirect heat exchange
Implementation Method 5
the adsorption zone has at least two beds of fluidized solid adsorbent particles, and wherein the solid adsorbent particles are flowing downwards from bed to bed
Data Source
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AI summary
The present invention relates to a process for capturing carbon dioxide from a gas stream. The gas stream is contacted with solid adsorbent particles in an adsorption zone. The adsorption zone has at least two beds of fluidized solid adsorbent particles, and the solid adsorbent particles are flowing downwards from bed to bed. The solid adsorbent particles comprise 15 to 75 weight% of organic amine compounds. The gas stream entering the adsorption zone has a dew point which is at least 5 °C below the forward flow temperature of the coolest cooling medium in the adsorption zone. Carbon dioxide enriched solid adsorbent particles are heated, and then regenerated. The desorption zone has at least two beds of fluidized solid adsorbent particles, and the stripping gas is steam. The regenerated particles are cooled and recycled to the adsorption zone.