Scope for reductions in the cost of CO2 capture using flue gas scrubbing with amine solvents

A previous IEA GHG study Of CO2 capture from a pulverized coal (PC) power plant using an amine solvent for flue gas scrubbing has been used as the basis for calculations of the reductions in electricity and CO2, avoidance costs that might be achievable through improved thermodynamic integration between the CO2, capture plant and the steam cycle, the use of a solvent with lower regeneration energy requirements and solvent storage to allow rapid load changes and electricity ‘storage’. It was predicted that the efficiency penalty for CO2, capture for PC plant with flue gas scrubbing using an amine solvent can be reduced to 20 per cent (from 2 8 per cent) with improved thermodynamic integration and lower-energy solvent, giving a 10 per cent reduction in electricity costs, from $63.5/MW h to $57.4/MW h, and a 25 per cent reduction in the cost of CO, avoided, from $45/t to $34/t. These values are both lower than predictions for the gasifier-based coal power plant in the original IEA GHG study. Reductions in the average cost of electricity of 6-7 per cent were estimated using solvent storage, giving a cost of electricity of $56.73/MWh and $33/t CO2 avoided for an integrated plant with monoethanolamine (MEA) as the solvent. Also, CO2 venting would allow an additional 20-25 per cent increase in output to be maintained indefinitely when $/MW h electricity prices were 2-3 times greater than the $/t penalty for CO2 discharges.