CO2 Absorbent Heat Exchange and Flash Vaporization
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Solution Overview
Problem
Existing combustion exhaust gas treatment systems face limitations in plant design flexibility and thermal efficiency due to the need for multiple heat exchangers, which also lead to reduced power generation efficiency and increased steam consumption.
Innovation Solution
The system incorporates a flash tank and vapor recompression apparatus to reduce the pressure and vaporize the CO2 absorbent, and additional heat exchangers to recover and apply heat efficiently, allowing for reduced steam consumption and improved absorbent temperature management.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Temperature
If multiple heat exchangers are provided in the absorbent line between the CO2 absorption column and desorption column, then the absorbent temperature can be controlled, but the plant design flexibility is reduced and the degree of freedom in plant design is limited
Solution Approach 1:
The patent combines multiple heat exchanger functions into a single integrated heat exchanger unit that performs both cooling of the rich absorbent and heating of the lean absorbent. This merging approach maintains the necessary temperature control while restoring plant design flexibility by reducing the number of separate components that constrain the system layout and design options.
Solution Approach 2:
The heat exchanger is designed to perform multiple functions simultaneously: cooling the rich absorbent from the absorption column, heating the lean absorbent for the desorption column, and potentially recovering heat for other system uses. This multi-functionality eliminates the need for separate dedicated heat exchangers for each function, thereby improving plant design flexibility while maintaining temperature control capabilities.
2Loss of energy
If multiple heat exchangers are provided in the absorbent line, then thermal efficiency can be improved, but the device complexity increases
Solution Approach 1:
The patent merges multiple heat exchanger functions into a single integrated unit that handles both rich absorbent cooling and lean absorbent heating. This consolidation reduces device complexity by eliminating redundant components, connections, and control systems while maintaining the thermal efficiency benefits of heat recovery between the two absorbent streams.
Solution Approach 2:
The integrated heat exchanger performs multiple thermal functions within a single device structure, including cooling rich absorbent, heating lean absorbent, and potential heat recovery for auxiliary uses. This multi-functionality reduces the overall number of components and simplifies the system architecture while preserving the thermal efficiency improvements that would otherwise require multiple separate heat exchangers.
3Quantity of substance
If chemical absorption method is used to separate CO2, then CO2 removal capability is achieved, but power generation efficiency decreases due to large thermal energy consumption
Solution Approach 1:
The patent implements continuous heat recovery from the rich absorbent stream to preheat the lean absorbent stream in an integrated heat exchanger system. This continuous heat exchange process reduces the external thermal energy required for the desorption process, thereby maintaining CO2 removal capability while reducing the overall thermal energy consumption that would otherwise decrease power generation efficiency.
Solution Approach 2:
The system optimizes the thermal parameters of the absorbent streams by recovering heat from the hot rich absorbent to preheat the cooler lean absorbent before it enters the desorption column. This parameter optimization reduces the temperature differential that must be provided by external heating, thereby reducing thermal energy consumption and improving power generation efficiency while maintaining effective CO2 separation.
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 enhances plant design flexibility, maintains high thermal efficiency, and reduces steam consumption, thereby suppressing the decrease in power generation efficiency while ensuring effective CO2 removal.
Implementation Method 1
a flash tank (91) to reduce the pressure of CO2 absorbent pooled in a liquid reservoir at the bottom of the desorption column
Implementation Method 2
vaporize the CO2 absorbent
Implementation Method 3
separating the vaporized absorbent into a gas phase and a liquid phase
Implementation Method 4
a first heat exchanger (A) to apply heat recovered by the heat medium to the CO2 absorbent
Implementation Method 5
heat recovered by the heat medium
Implementation Method 6
vapor recompression apparatus to compress the vaporized absorbent
Data Source
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AI summary
A combustion exhaust gas treatment system comprising: a heat exchanger (A) for recovering heat contained in the combustion exhaust gas into heat medium, an absorption column for obtaining CO2 removed gas by absorbing CO2 in the combustion exhaust gas into absorbent, a heat exchanger (B) for applying heat recovered by heat medium to the CO2 absorbed absorbent, a desorption column for desorbing the absorbent by removing CO2 from the CO2 absorbed absorbent, a flash tank for flash vaporizing the desorbed absorbent and a heat exchanger (E) for transferring heat from the desorbed absorbent to the CO2 absorbed absorbent, wherein the CO2 absorbed absorbent can be supplied from the absorption column to the desorption column via the heat exchanger (E) and the heat exchanger (B) in this order, and the desorbed absorbent can be supplied from the desorption column to the absorption column via the flash tank and the heat exchanger (E) in this order.