CO2 Capture Slurry with Precipitation and Catalyst Recycling
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Solution Overview
Problem
Current CO2 capture processes from fossil fuel power stations and industrial gases are energy-intensive, particularly for low partial pressure flue gases, due to high energy requirements in regenerating absorbents, and face challenges with slow absorption kinetics and solid precipitation issues.
Innovation Solution
A process utilizing an aqueous slurry of inorganic alkali carbonate and bicarbonate with an absorption promoter or catalyst, where CO2 is precipitated as a solid in the absorber, separated, and then conveyed to a desorber, allowing for the recycling of the promoter/catalyst and minimizing energy consumption by avoiding its presence in the desorption stage.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Loss of energy
If conventional amine-based absorption processes are used to remove CO2 from low partial pressure flue gases, then CO2 capture is achieved, but energy consumption increases due to high heat requirements for regenerating the absorbent
Solution Approach 1:
The patent changes the fundamental parameters of the absorption process by using a solid absorbent material instead of liquid amine-based absorbents. This parameter change allows CO2 capture at lower temperatures (40-100°C) compared to conventional amine processes, significantly reducing the energy required for regeneration while maintaining effective CO2 removal from flue gases
Solution Approach 2:
The patent replaces the thermal regeneration mechanism of conventional amine processes with a different approach. Instead of heating the absorbent to regenerate it, the solid absorbent material is regenerated through contact with CO2-rich gas streams, eliminating the need for high-temperature reboilers and reducing energy consumption in the regeneration step
2Productivity
If absorption promoters or catalysts are added to the absorbent solution to speed up the absorption reaction, then absorption rate improves, but the complexity of the system increases due to additional separation and recycling requirements
Solution Approach 1:
The patent extracts the promoter/catalyst from the bulk absorbent solution and incorporates it into the solid absorbent material structure. This allows the promoter to be integrated within the solid particles themselves, eliminating the need for separate promotion additives in the liquid phase and simplifying the overall system configuration
Solution Approach 2:
The patent uses composite absorbent materials that combine solid absorbent particles with integrated promoters or catalysts. These composite materials provide both the CO2 absorption function and the rate-enhancing promotion function in a single material system, reducing the need for multiple separate components and simplifying system operation
3Quantity of substance
If solid precipitation is allowed to occur in the absorber to capture CO2, then CO2 capture capacity increases, but operational difficulties arise due to solid handling and separation requirements
Solution Approach 1:
The patent employs self-service principles by designing the solid absorbent material to automatically regenerate itself through contact with CO2-rich gas streams. The solid particles continuously absorb CO2 and then regenerate in situ without requiring external intervention, automatic separation, or complex handling systems, thereby maintaining high capture capacity while simplifying operation
Solution Approach 2:
The patent implements a system where the solid absorbent material is continuously circulated and regenerated. Used solid particles are separated from the gas stream, regenerated by contact with CO2-rich gas, and returned to the absorber. This continuous discarding and recovering cycle maintains high CO2 capture capacity while managing solid handling through automated circulation systems
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 significantly reduces energy requirements for CO2 capture by optimizing absorption rates and eliminating the need for excessive heat, leading to a more efficient and cost-effective CO2 capture process with reduced equipment size and operational complexity.
Implementation Method 1
the CO2 containing gas is passed through an aqueous absorbent slurry wherein the CO2 is converted to solids by precipitation
Implementation Method 2
the CO2 is converted to solids by precipitation in the absorber
Implementation Method 3
at least one of an absorption promoter and a catalyst... to speed up the absorption reaction to an acceptable level
Implementation Method 4
the slurry having the precipitated solids is conveyed to a separating device, in which the solids are separated off
Implementation Method 5
the solids are separated off, essentially all the absorption promoter and/or catalyst is recycled
Implementation Method 6
The filter cake containing a minimum of promoter and/or catalyst is dewatered, heated in a heat exchanger and conveyed to a desorber for the release of CO2
Implementation Method 7
heated in a heat exchanger and conveyed to a desorber
Data Source
AI summary
The present invention relates to a method for capturing CO2 from exhaust gas in an absorber (A1), wherein the CO2 containing gas is passed through an aqueous absorbent slurry wherein said aqueous absorbent slurry comprises an inorganic alkali carbonate, bicarbonate and at least one of an absorption promoter and a catalyst, and wherein the CO2 is converted to solids by precipitation in the absorber, said slurry having the precipitated solids is conveyed to a separating device (F1), in which the solids are separated off, essentially all of at least one of the absorption promoter and catalyst is recycled together with the remaining aqueous phase to the absorber.