Ammoniated CO2 Absorber with Recirculation Barrier
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Solution Overview
Problem
Existing CO2 capture systems from flue gas streams are complex and costly, with high operating and capital expenses, and often result in ammonia slip and solid carbonate particle formation, leading to clogging risks.
Innovation Solution
A method and system that recirculates CO2-enriched ammoniated solution through both absorption stages, acting as a barrier to gaseous ammonia, and maintains temperatures above ammonium bicarbonate precipitation to prevent solid formation, using a single tower design with counter-current flow and optimized liquid-to-gas ratios for efficient CO2 capture with minimal ammonia slip.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Object-generated harmful factors
If recirculated CO2-enriched ammoniated solution is passed through both absorption stages, then ammonia slip is reduced, but system complexity increases
Solution Approach 1:
The absorption system is divided into two distinct absorption stages (first and second stages) with different functions. The first stage primarily absorbs CO2 while the second stage absorbs both CO2 and ammonia, allowing the recirculated solution to act as a barrier to ammonia slip. This segmentation enables targeted control of ammonia emissions without requiring complete system redesign.
Solution Approach 2:
The recirculated CO2-enriched ammoniated solution is prepared in advance and fed to the second absorption stage before the flue gas enters. This preliminary positioning of the recirculated solution creates a barrier that prevents ammonia from escaping with the flue gas, thereby reducing ammonia slip before it can become a harmful emission.
2Reliability
If temperature is maintained above ammonium bicarbonate precipitation point, then solid carbonate formation is prevented, but CO2 capture efficiency may be reduced
Solution Approach 1:
The temperature parameter of the ammoniated solution is carefully controlled and maintained above the precipitation point of ammonium bicarbonate throughout the absorption process. This parameter control prevents solid carbonate particle formation and associated clogging risks, ensuring reliable continuous operation while maintaining adequate CO2 capture efficiency through optimized absorption conditions.
3Productivity
If three absorbers are used to improve CO2 capture efficiency, then capture performance increases, but operating cost and capital cost increase
Solution Approach 1:
The patent merges the functions of multiple absorbers into a single integrated absorption system with two absorption stages. The recirculated CO2-enriched ammoniated solution connects both stages, allowing the system to achieve high CO2 capture efficiency without requiring three separate absorber units. This consolidation reduces both capital costs (fewer vessels) and operating costs (simplified operation and maintenance) while maintaining productivity.
Solution Approach 2:
The recirculated CO2-enriched ammoniated solution serves multiple functions: it acts as an absorbent in the first stage, provides a barrier against ammonia slip in the second stage, and can be regenerated for continued use. This multi-functionality allows a single absorption system to achieve what previously required three separate absorbers, reducing system complexity while maintaining high CO2 capture efficiency.
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 reduces ammonia slip, operating costs, and capital expenditures while preventing solid carbonate formation, enhancing CO2 capture efficiency and system robustness, with reduced energy consumption and simpler design.
Implementation Method 1
forwarding the recirculated CO2-enriched ammoniated solution first through the second absorption stage, and then through the first absorption stage
Implementation Method 2
the recirculated CO2-enriched ammoniated solution acts as a barrier to gaseous ammonia
Implementation Method 3
the recirculated CO2-enriched ammoniated solution and the CO2-lean ammoniated solution are kept at a temperature, while passing through the first and second absorption stages, which is above a temperature at which ammonium bicarbonate particles may start to precipitate
Data Source
Figure 1
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Figure 3~4
AI summary
A system for capturing CO2 from a flue gas stream comprises: - a CO2 absorber (18) comprising first and second absorption stages (54, 56), - first contacting means (58, 60) for contacting, in the first stage (54), the flue gas stream (FG) with a mixture of CO2-lean ammoniated solution and recirculated CO2-enriched ammoniated solution, - second contacting means (62, 64) for contacting, in the second stage (56), partly cleaned flue gas stream with the recirculated CO2-enriched solution, - a device (66) for collecting the mixture of CO2-lean solution and recirculated CO2-enriched solution, - a pipe (20) for passing a first portion of the collected CO2-enriched solution for regeneration, - a CO2-lean solution pipe (34) for passing the CO2-lean solution from regeneration to the first stage (54), and - a recirculation pipe (74) for passing a second portion of the collected CO2-enriched solution to the second stage (56).