Hybrid Membrane-Solvent CO2 Capture Process
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Current CO2 capture processes from post-combustion gases in power plants are energy-intensive and costly, aiming to achieve high CO2 capture efficiency with minimal energy and capital costs, particularly in coal-fired power plants, while meeting stringent purity and cost requirements.
Innovation Solution
A hybrid process combining membrane-based CO2 pre-concentration followed by a two-stage solvent regeneration system, utilizing a high flux, low pressure drop CO2-selective membrane and an air-based secondary stripper to enhance CO2 purity and reduce energy consumption.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If conventional solvent-based CO2 capture is used, then CO2 can be removed from post-combustion gases, but energy consumption and capital costs are high
Solution Approach 1:
The CO2 capture process is divided into two distinct stages: a membrane-based pre-concentration stage followed by a solvent-based stripping stage. This segmentation allows each stage to operate optimally for its specific function, reducing overall energy consumption while maintaining high capture efficiency.
Solution Approach 2:
The membrane unit performs preliminary CO2 concentration from the flue gas stream before the solvent-based stripping process. This pre-concentration step reduces the burden on the subsequent solvent system, lowering energy requirements for CO2 removal while achieving the target purity.
2Reliability
If conventional solvent-based CO2 capture is used, then CO2 can be removed from post-combustion gases, but capital costs for equipment are high
Solution Approach 1:
By segmenting the capture process into membrane pre-concentration and solvent stripping stages, the system reduces the size and complexity of individual equipment components. The membrane unit handles the bulk of CO2 removal with simpler, more compact equipment, reducing capital costs.
Solution Approach 2:
The membrane unit acts as an intermediary between the flue gas and the solvent system. It performs initial CO2 concentration, reducing the volume of gas that requires processing by the solvent system, thereby reducing equipment size and capital investment.
3Manufacturing precision
If CO2 is captured with high purity, then compression and utilization become feasible, but energy consumption increases
Solution Approach 1:
The process segments CO2 purification into two functional stages: the membrane unit provides initial concentration and preliminary purification, while the solvent stripping unit completes the purification to achieve high purity. This division reduces the energy required compared to a single-stage high-purity system.
Solution Approach 2:
The membrane-based pre-concentration step performs preliminary purification and concentration before the final solvent stripping stage. This preliminary action reduces the energy burden on the final purification stage, achieving high purity with lower overall energy consumption.
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 process achieves 90% CO2 capture with 95% purity at reduced energy and capital costs, utilizing membrane pre-concentration to enhance CO2 enrichment and a two-stage stripping system for efficient solvent regeneration, thereby lowering overall energy requirements and capital expenditures.
Implementation Method 1
pre-concentrating a CO2 component of the boiler exhaust gas by passing the flue gas through a CO2-selective membrane module
Implementation Method 2
contacted with a scrubbing solvent to absorb CO2 and provide a carbon-rich scrubbing solvent
Implementation Method 3
absorbed CO2 is stripped from the carbon-rich scrubbing solvent by a two-stage CO2 stripping system
Data Source
AI summary
A process for recovery of CO2 from a post-combustion gas includes pre-concentrating a CO2 component of the post-combustion flue gas by passing the post-combustion gas through a CO2-selective membrane module to provide a CO2-enriched permeate stream and a CO2-lean reject stream. Next, in a CO2 absorber, both the CO2-enriched permeate stream and CO2 lean reject stream, fed to separate feed locations on the CO2 absorber, are contacted with a scrubbing solvent to absorb CO2 and provide a carbon-rich scrubbing solvent. Finally, absorbed CO2 is stripped from the carbon-rich scrubbing solvent by a two-stage CO2 stripping system. The CO2-selective membrane may be a high flux, low pressure drop, low CO2 selectivity membrane. The two stage stripping system includes a primary CO2 stripping column for stripping CO2 from the carbon-rich scrubbing solvent exiting the CO2 absorber, and a secondary CO2 stripping column for stripping CO2 from a carbon-lean scrubbing solvent exiting the primary CO2 stripping column. Apparatus for CO2 removal from post-combustion gases in a pulverized coal power plant incorporating the described processes are described.