Energy-efficient CO2 capture with piperazine and 3-dimethylamino-1-propanol blends: Modeling, experimental validation, and regeneration energy optimization

The contribution of solvent regeneration energy to amine-based CO₂ capture processes is a major hurdle to their large-scale economic viability. It is important to develop solvents that reduce CO₂ capture cost without compromising the process performance or operations. To reduce regeneration energy, this study focuses on the development of aqueous blends of piperazine (PZ) and 3-dimethylamino-1-propanol (3DMA1P) as an energy-efficient absorbent for CO₂ capture. The study relies on rigorous modeling, supported by experimental data. The experimental data from this study and the literature includes CO₂ solubility, NMR speciation, heat of absorption, and physical properties. To determine the potential application of PZ-3DMA1P blend for CO₂ capture, their equilibrium CO₂ solubility, cyclic capacity, heat of absorption, and, more importantly, solvent regeneration energy was investigated. Regeneration energy is calculated and evaluated under the influence of various operating parameters such as absorber temperature (313.15–343.15 K), stripper temperature (373.15–403.15 K), CO₂ partial pressure (1–30 kPa), stripper total pressure (200–400 kPa), CO₂ recovery (80–95 %), amine blending ratio (PZ:3DMA1P, 0–10:40–30 wt.%) and water concentration (60–90 wt.%). The results were compared with those obtained under the same operating conditions using monoethanolamine (MEA) 30 and 40 wt.%, and CESAR-1, the benchmark solvents. Results of the current study for blends of PZ and 3DMA1P are promising, and the solvent system exhibits higher CO₂ absorption capacity and lower regeneration energy compared to MEA and CESAR-1. A comprehensive parametric analysis of regeneration energy enhances the applicability of the results across a diverse range of industries.