Extensive research efforts have been applied to obtain more efficient and less cost-intensive absorption-based processes and solvent systems for CO₂capture during the last 15-20 years. High concentratedaqueous solutions of piperazine (PZ) have been suggested as a good replacement for the current bench-mark solvent mono-ethanolamine (MEA). So far, the research on concentrated PZ solutions has mainlyfocused on the development and evaluation of various configurations for the post-combustion CO₂cap-ture process. The present paper studies the integration of a configuration based on high-pressure flashregeneration with the upstream power plant. The main focus is on the overall energy performance, but aqualitative analysis of the effect of flexible operation is added as this is important for the optimization ofthe total plant. A power plant integrated with the optimal PZ-based capture plant is found to have a netelectric efficiency of 37.4%, which is 7.2% less than the reference power plant without CO₂capture. Theefficiency penalty when using an MEA-based capture plant including lean-vapour compression is 9.1%.

The solvent and the dissolved CO₂ concentrations are two essential properties of CO₂ absorption processes. Currently, they are typically monitored using time-consuming offline analytical techniques. Initial development efforts aiming at a cost-effective and reliable inline monitoring system are described. Using a fractional factorial experimental design covering six solvent properties and five analytical techniques, it is demonstrated that the CO₂ and solvent concentrations correlate well with the density and refractive index. Applying a simplistic multivariate model to solvent samples from an industrial pilot plant indicated good potential for predictive use. Future work should focus on the development of a more accurate multivariate model, on the modeling of more solvents, and on combining the results with available process data.

This work summarises the results of the design of novel separation processes for CO₂ removal from flue gas based on precipitating amino acid solvents. The processes here described (DECAB, DECAB Plus and pH-swing) use a combination of enhanced CO₂ absorption (based on the Le Chatelier;s principle) and / or enhanced CO₂ desorption (based on pH-shift), which contribute substantially to the reduction of regeneration energy. An evaluation of these processes has been developed based on literature data, thermodynamic principles and experimental data. As solvent example, the potassium salt of taurine was selected. The results show that these processes are environmentally friendly (no emissions to the air, lower ecotoxicity) and have lower energy consumption than conventional MEA. The DECAB Plus process has been identified as the option with lower energy consumption (66% of conventional MEA- ie ca 2.4 GJ/t CO₂). This study has established the potential of precipitating amino acids as an energy effective alternative to alkanol amines. The future work will focus on determining the cost of CO₂ avoidance and investigating other solvents that will further lead to benefits over conventional processes.