Fluidized Bed Reactor for CO2 Mineralization in Fly Ash
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Solution Overview
Problem
Current methods for capturing CO2 from coal combustion processes are energy-intensive and produce additional by-products, and none effectively capture and mineralize flue gas CO2 under actual plant combustion conditions, especially with fly ash or bottom ash.
Innovation Solution
A fluidized bed reactor device that introduces flue gas through a distributor plate into a volume of fly ash, allowing for simultaneous capture and mineralization of CO2, with a blower providing pressurization and a pleated fabric filter separating reacted gases from ash, enabling efficient CO2 sequestration.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Quantity of substance
If conventional CO2 capture methods (pre-combustion, oxy-fuel firing, post-combustion) are used, then CO2 can be captured from coal combustion processes, but the processes are energy-intensive and produce additional by-products requiring special handling and disposal
Solution Approach 1:
The patent combines CO2 capture and mineralization into a single integrated process using a fluidized bed reactor. The fly ash from coal combustion serves dual purposes: as a catalyst for CO2 mineralization and as the mineralizing agent itself. This merging eliminates the need for separate capture and disposal processes, reducing overall energy consumption while avoiding additional by-product streams.
Solution Approach 2:
The system uses the fly ash generated during coal combustion itself as the reagent for CO2 mineralization. The alkaline components of the fly ash (calcium oxide, calcium hydroxide, calcium carbonate) naturally react with CO2 to form stable mineral products. This self-service approach eliminates the need for external chemicals or energy-intensive separation processes, directly addressing the energy consumption problem.
2Quantity of substance
If conventional CO2 capture methods are used, then CO2 can be captured, but additional by-products are produced which require special handling and disposal methods
Solution Approach 1:
The patent converts the harmful CO2 emissions and the often-discarded fly ash into beneficial stable mineral products. The fly ash, which would otherwise require disposal, becomes the reagent that captures CO2 and transforms it into solid carbonate minerals. This process eliminates additional by-products by utilizing existing waste materials to sequester the harmful gas.
Solution Approach 2:
Instead of discarding fly ash as waste requiring special handling, the system recovers its alkaline components to perform CO2 mineralization. The fly ash is introduced into the fluidized bed reactor where it reacts with CO2, transforming both the waste material and the harmful gas into stable carbonate products that can be safely disposed of or utilized.
3Quantity of substance
If batch laboratory carbonation experiments are conducted, then CO2 can be infused into alkaline solid wastes, but diffusion limitations prevent efficient CO2 contact with the ash sample
Solution Approach 1:
The patent transitions from static batch experiments to a dynamic fluidized bed system. The fly ash particles are continuously suspended and circulated in the fluidized bed, ensuring constant movement and exposure to CO2. This dynamic environment eliminates diffusion limitations by maintaining turbulent mixing and maximizing the contact surface area between CO2 and ash particles throughout the reaction zone.
Solution Approach 2:
The system uses gas flow through the fluidized bed to overcome diffusion limitations. Pressurized CO2-rich flue gas is introduced into the bed, creating upward flow that continuously suspends and mixes the ash particles. This pneumatic agitation ensures efficient mass transfer and CO2 contact with all ash surfaces, dramatically improving reaction efficiency compared to static batch methods.
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
The fluidized bed reactor effectively captures and mineralizes coal combustion CO2, increasing inorganic carbon content in fly ash by a factor of thirty, reducing greenhouse emissions and stabilizing ash for safe disposal or reuse.
Implementation Method 1
a fluidized bed reactor device for sequestering flue gas CO2
Implementation Method 2
a pleated fabric filter separating reacted gases from ash
Implementation Method 3
with a blower providing pressurization
Implementation Method 4
the carbonation process could help capture and minimize CO2 emissions into the atmosphere
Data Source
AI summary
A fluidized bed reactor device for sequestering flue gas CO2 from a flue gas source is provided. The fluidized bed reactor device comprises an operating portion having a first end and a second end. A flue gas inlet is formed at the first end of the operating portion with the flue gas inlet receiving flue gas from the flue gas source. A flue gas outlet formed at the second end of the operating portion. A distributor plate is mounted within the operating portion adjacent the first end of the operating portion. A volume of fly ash is encased within the operating portion between the second end and the distributor plate with the flue gas traveling through the distributor plate and the fly ash creating reacted flue gas wherein the reacted flue gas exits the operating portion through the flue gas outlet.