Improving CO<sub>2</sub> Capture Efficiency with High-Capacity Solvents: Addressing Temperature-Induced Mass Transfer Limitations
Yi-Min Chen, Hui-Ting Hsu, Yu‐Jeng Lin
Abstract
High Resolution Image Download MS PowerPoint Slide Solvents with higher absorption capacities have the potential to enhance the CO 2 capture performance. However, practical absorbers often experience temperature bulge effects due to the exothermic nature of CO 2 absorption, which can cause mass transfer limitations and reduce the benefits of increased capacity. This study investigates the impact of temperature-induced mass transfer limitations in high-capacity solvents and explores the effectiveness of intercooling strategies to address thermal effects. Adiabatic, intercooled, and isothermal CO 2 absorbers are modeled in Aspen Plus using the reference solvent monoethanolamine (MEA) and high-capacity solvents 2-amino-2-methyl-1-propanol (AMP) and piperazine (PZ). In adiabatic absorbers, high-capacity solvents experience more pronounced penalties from the temperature bulge compared with MEA, offsetting their inherently higher capacity. The generic solvent approach indicates that both solvent capacity and heat of absorption are key factors influencing temperature-induced mass transfer limitations, with AMP being adversely impacted by both. Solvent intercooling effectively mitigates the temperature increase and restores the inherent solvent capacity. Recycle intercooling offers the most improvement, reducing the required solvent rate for AMP by 39%. These findings emphasize the necessity of optimal intercooling design to fully leverage the benefits of high-capacity solvents, thereby contributing to the development of cost-effective CO 2 capture processes.