Theoretical and experimental study of the ammonia/water absorption process using a flat sheet membrane module

A hydrophobic microporous membrane contactor was proposed and studied as an absorber for an ammonia/water absorption cycle. The heat and mass transfer process in the adiabatic flat sheet membrane module was investigated experimentally and analytically. For the experimental study, a membrane absorber test bench was designed and built. Moreover, a unidimensional model was developed and validated with the experimental results. The influence of the temperature, concentration, flow rate and membrane characteristics on the absorption process was evaluated. For the conditions considered in this study, the results indicate that the absorption flux is clearly governed by the mass transfer in the liquid phase. The maximum absorption flux was 4.7 · 10−3 kg/m2 s with a solution flow rate of 45 kg/h. According to the model, the hydrophobic membrane should be as thin as possible and the pore diameter between 0.03 μm and 0.10 μm.