Modeling and simulation of CO2 capture in aqueous ammonia with hollow fiber composite membrane contactors using a selective dense layer

• Published in: Chemical engineering science 2018-11, Vol.190, p.345-360
• Main Authors: Villeneuve, Kévin, Albarracin Zaidiza, David, Roizard, Denis, Rode, Sabine
• Format: Article
• Language: English
• Subjects: Aqueous ammonia; Chemical and Process Engineering; CO2 capture; Composite membrane; Engineering Sciences; Modeling; Selective membrane contactor
• ISSN: 0009-2509; 1873-4405
• DOI: 10.1016/j.ces.2018.06.016

[Display omitted] •Hollow Fiber Membrane Contactors permit volume reduction in CO2 capture using ammonia.•Composite membranes permit to avoid membrane wetting by liquid breakthrough.•The reactor is modeled using a one-dimensional adiabatic multi-component approach.•The model has been validated using both, laboratory-scale and pilot-scale data.•A dense selective layer reduces ammonia slip but increases mass-transfer resistance. Aqueous ammonia is a promising chemical absorbent for CO2 capture but its high volatility leads to important solvent leakage necessitating expensive solvent recovery strategies. This study investigates the potential of using hollow fiber membrane contactors with composite membranes instead of packed columns to reduce solvent leakage. In this study, we used a composite membrane with a thin, dense selective layer (non-porous) coated on a microporous support to favor CO2 transfer over NH3. We developed one-dimensional adiabatic multi-component transfer models to simulate the capture process using both hollow fiber membrane contactors and packed columns. These models were validated with laboratory-scale and pilot-scale data. Simulations under industrial relevant operation conditions were conducted to investigate process performance as a function of membrane characteristics, i.e. membrane dense layer thickness, selectivity and the micro-porous support mass-transfer coefficient. For contactors using homemade selective membranes, the CO2 specific absorption capacity was of 2.7 mol/m3/s, which is roughly twenty times higher than values for our simulations in packed columns. The corresponding NH3 slip reduction was of 4.3%. A parametric study revealed that thick dense membrane layers led to greater reductions of ammonia slip but that this corresponded to lower specific CO2 absorption capacity, highlighting an important trade-off between two performance parameters.