Dispersed Bubble Reactor for Compact CO2 Capture
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Solution Overview
Problem
Conventional gas-liquid contacting equipment is inefficient in capturing CO2 from large gas streams, such as those in IGCC and coal-fired power plants, due to limitations in handling high gas volumes, precipitated solids, and high energy consumption, with existing systems requiring large equipment sizes and high solvent circulation rates, leading to operational challenges and energy inefficiencies.
Innovation Solution
A dispersed bubble reactor (DBR) system that enhances gas-liquid contact and mass transfer through a concentration gradient, using a circulating liquid stream to absorb CO2 from gas streams, with finely dispersed gas bubbles creating a large interfacial area for absorption, and incorporating a regenerator to manage precipitates and reduce energy consumption.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Quantity of substance
If conventional packed bed or tray tower absorber is used to capture CO2 from large gas streams, then CO2 absorption capacity is improved, but equipment size becomes extremely large (over 100 feet in inner diameter)
Solution Approach 1:
The invention divides the gas stream into multiple fine bubbles distributed throughout the liquid column, creating numerous small contact zones instead of relying on a single large contact area. This segmentation of the gas phase into dispersed bubbles enables high CO2 absorption capacity within a compact reactor volume, resolving the contradiction between absorption capacity and equipment size.
Solution Approach 2:
The invention transitions from traditional horizontal or vertical tower configurations to a three-dimensional dispersed bubble system where gas-liquid contact occurs throughout the entire reactor volume. By utilizing the third dimension (vertical dispersion of bubbles throughout the liquid column), the system achieves high absorption capacity without requiring excessive horizontal diameter.
2Productivity
If large solvent circulation rates are used to handle high gas volumes, then CO2 capture efficiency is improved, but energy consumption increases significantly
Solution Approach 1:
The dispersed bubble reactor design enables efficient mass transfer through natural convection and bubble rise dynamics, reducing reliance on high-velocity forced circulation. The system leverages the inherent buoyancy-driven flow and interfacial area generation from bubble formation to achieve high CO2 capture efficiency with lower pumping energy requirements compared to conventional high-circulation-rate systems.
3Ease of operation
If conventional contacting equipment is used to handle precipitated solids, then operational simplicity is maintained, but equipment reliability deteriorates due to blockages and foaming
Solution Approach 1:
The invention segments the liquid phase into numerous small circulation channels and contact zones, preventing localized accumulation of precipitated solids. This segmentation eliminates the formation of large stagnant regions where solids could accumulate and cause blockages, thereby maintaining operational simplicity while significantly improving reliability in handling precipitating systems.
4Volume of stationary object
If multiple tower design is implemented to reduce single tower size, then equipment size is reduced, but device complexity and cost increase prohibitively
Solution Approach 1:
The invention achieves compact sizing by utilizing vertical bubble dispersion and three-dimensional gas-liquid contact throughout the reactor volume, eliminating the need for multiple parallel towers. This dimensional approach to mass transfer enables a single reactor to handle large gas volumes efficiently, maintaining low device complexity and cost while achieving the desired size reduction.
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 DBR effectively captures over 90% of CO2 from industrial streams while handling precipitated solids, reducing equipment size and energy consumption by optimizing gas-liquid contact and heat transfer, thus improving the efficiency and cost-effectiveness of CO2 capture processes.
Implementation Method 1
Mass transfer is the net movement of mass from one location, usually meaning a stream, phase, fraction or component, to another
Implementation Method 2
a mass transfer system using a concentration gradient between two streams as the driving force for diffusion
Implementation Method 3
finely dispersed gas bubbles that enhances the gas-liquid contact and mass transfer through the creation of a large interfacial area between the gas bubbles from the inlet stream and the first stream
Implementation Method 4
handling precipitated solids
Implementation Method 5
a regenerator to manage precipitates
Data Source
AI summary
An apparatus to promote gas-liquid contact and facilitate enhanced mass transfer. The dispersed bubble reactor (DBR) operates in the dispersed bubble flow regime to selectively absorb gas phase constituents into the liquid phase. The dispersion is achieved by shearing the large inlet gas bubbles into fine bubbles with circulating liquid and additional pumped liquid solvent when necessary. The DBR is capable of handling precipitates that may form during absorption or fine catalysts that may be necessary to promote liquid phase reactions. The DBR can be configured with multistage counter current flow sections by inserting concentric cylindrical sections into the riser to facilitate annular flow. While the DBR can absorb CO2 in liquid solvents that may lead to precipitates at high loadings, it is equally capable of handling many different types of chemical processes involving solids (precipitates/catalysts) along with gas and liquid phases.