Compact CO2 Absorber Design for Mass Transfer Efficiency
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Current CO2 capture systems, particularly the CO2 absorber, are costly and inefficient due to high capital costs and diffusion resistance at the gas-liquid interface, limiting mass transfer and increasing the size of the equipment needed for effective carbon dioxide removal from flue gases.
Innovation Solution
A compact CO2 absorber design incorporating a co-current first or fog subsection, a co-current second or froth subsection, and a counter-current packed section, which reduces diffusivity resistance and increases the specific surface area for enhanced CO2 mass transfer, thereby minimizing equipment size and pressure drop while achieving better temperature control and absorption efficiency.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Volume of moving object
If conventional absorber design is used, then CO2 absorption can be achieved, but equipment size becomes large and capital cost increases
Solution Approach 1:
The absorber is divided into three distinct sections: a co-current fog section, a co-current froth section, and a counter-current packed section. Each section performs a specific function in the CO2 absorption process, allowing the system to achieve high capture efficiency in a compact configuration by segmenting the overall absorption function across multiple zones with different flow regimes and contact mechanisms.
Solution Approach 2:
The invention transitions from conventional two-phase flow patterns to a three-phase system by introducing liquid fog droplets into the gas stream. This adds a dimensional aspect to the mass transfer process, creating intense mixing and heat transfer between the liquid and gas phases in the fog section, which significantly enhances CO2 absorption efficiency per unit volume.
2Productivity
If conventional packed bed is used, then CO2 transfer occurs, but diffusion resistance limits mass transfer efficiency
Solution Approach 1:
The liquid fog droplets in the co-current section create intense mechanical mixing and turbulence as they collide with the gas stream and each other. This mechanical action effectively reduces diffusion resistance by creating chaotic motion that enhances mass transfer coefficients, allowing CO2 to transfer more rapidly from the gas phase to the liquid phase compared to conventional laminar flow packed beds.
Solution Approach 2:
The system utilizes pneumatic principles by injecting liquid fog into the gas stream, creating a dispersed liquid phase that enhances mass transfer. The fog droplets are suspended in the gas flow, creating intense interfacial area for CO2 absorption while the pneumatic injection system controls the distribution and impact of liquid droplets to optimize transfer efficiency.
3Productivity
If high absorption rate is achieved, then CO2 capture efficiency increases, but pressure drop increases
Solution Approach 1:
Each section of the absorber is designed with local quality optimizations: the fog section uses high-velocity liquid injection for intense mixing, the froth section uses controlled liquid distribution for sustained contact, and the packed section uses structured packing for efficient mass transfer. This localized optimization allows high overall absorption rates while controlling pressure drop in each zone according to its specific function.
Solution Approach 2:
The system changes flow parameters dynamically across different sections: transitioning from liquid-phase flow in the fog section to vapor-liquid froth in the middle section, and finally to gas-liquid counter-current flow in the packed section. These parameter changes optimize the balance between absorption efficiency and pressure drop by selecting appropriate flow regimes for each functional zone.
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 compact design increases CO2 mass transfer by 4-6 times, reduces equipment size, and minimizes pressure drop, making the CO2 capture process more cost-effective and efficient while maintaining a balance between absorption driving force and reaction kinetics.
Implementation Method 1
The CO2 absorption chemical reaction kinetics and diffusion of the CO2 through both the liquid-gas interface and into the bulk liquid phase affect the overall CO2 mass transfer
Implementation Method 2
the amine reacts with the CO2 to form a carbamate or bicarbonate salt along with a protonated amine to balance the overall charge
Implementation Method 3
the amine reacts with the CO2 to form a carbamate or bicarbonate salt along with a protonated amine to balance the overall charge
Implementation Method 4
the liquid, CO2 rich amine from the bottom of the absorber A, is passed through a heat exchanger B to improve efficiency before being heated to a higher temperature in the stripper C
Implementation Method 5
The stripper C removes the CO2 as a gas from the amine solution to produce a lean, or CO2 deficient solution
Data Source
AI summary
An acid gas absorber includes a co-current flue gas-lean solution section and a packed counter-current flue gas-liquid phase section useful in a method of capturing an acid gas from flue gas in a more efficient and cost effective manner.