Optimization of the various modes of flexible operation for post-combustion CO2 capture plant

• Flexible operation modes for post-combustion CO2 capture plant have been optimized.
• A detailed absorption/desorption model is used for the analysis and optimization.
• The formulation includes market value of captured CO2, and emission penalties.
• Simultaneous use of the partial capture and solvent storage is optimized.
• Effect of storage size, regeneration limits and energy price has also been evaluated.

One option to mitigate the adverse effect of power plant output loss from adding a CO2 capture plant is to operate it in flexible modes in which the capture level and/or regeneration rate are dynamically varied in response to varying electricity market demand and price. This can help the plant meet peak electricity demand and improve its overall profit. However, the benefit is offset by higher capital costs and/or CO2 emission penalty. Various modes of flexible operation including capture level reduction and solvent storage have been optimized for a given post-combustion capture system with typical daily electrical energy price patterns and the results are compared with those from a fixed point operation. Effects of varying storage capacities and energy price patterns have also been evaluated. Simultaneous use of the two flexible modes is also optimized and the result showed significantly higher cost savings compared to the individual uses.