Assessment of Hybrid Solvent—Membrane Configurations for Post-Combustion CO₂ Capture for Super-Critical Power Plants

Abstract

The reduction of fossil CO2 emissions from key relevant industrial processes represents an important environmental challenge to be considered. To enable large-scale deployment of low carbon technologies, a significant research and development effort is required to optimize the CO2 capture systems. This work assesses various hybrid solvent-membrane configurations for post-combustion decarbonization of coal-based super-critical power plants. As an illustrative chemical solvent, Methyl-Di-Ethanol-Amine was assessed. Various membrane unit locations were assessed (e.g., top absorber, before absorber using either compressor or vacuum pump). All investigated designs have a 1000 MW net power output with a 90% decarbonization ratio. Benchmark concepts with and without carbon capture using either reactive gas-liquid absorption or membrane separation technology were also evaluated to have a comparative assessment. Relevant evaluation tools (e.g., modeling, simulation, validation, thermal integration, etc.) were employed to assess the plant performance indicators. The integrated evaluation shows that one hybrid solvent-membrane configuration (membrane unit located at the top of absorption column) performs better in terms of increasing the overall net plant efficiency than the membrane-only case (by about 1.8 net percentage points). In addition, the purity of captured CO2 stream is higher for hybrid concepts than for membranes (99.9% vs. 96.3%). On the other hand, the chemical scrubbing concept has superior net energy efficiency than investigated hybrid configurations (by about 1.5–3.7 net percentage points).

Keywords

• fossil-based power plants
• CO₂ capture
• hybrid solvent-membrane configurations
• assessment of technical and environmental performance indicators