This work investigates the simultaneous removal of CO2 and H2S from natural gas by a novel PVDF membrane structure using CaCO3 nanoparticles aiming at increasing the efficiency of separation process. This work presents to what extent the CaCO3 nanoparticles improve the separation efficiency; proposes the optimum range of nanoparticle share in the membrane for achieving maximum separation in increased flow rates; and finally evaluating the effects of operational conditions such as temperature, flow velocity and species concentration on the system performance. A mathematical finite element model is developed to simulate the gas removal using a membrane module including both mass transfer equations and chemical reaction mechanism. A good agreement has been achieved between the modeling results and the measured data. It is found that 20% CaCO3 nano particle share in membrane gives the highest separation efficiency and any higher or lower nanoparticle concentration reduces the gas separation efficiency. Gas and fluid velocities have a high impact on separation efficiency. For example, increase in gas velocity from 5 m/s to 20 m/s leads to reduction in CO2 removal efficiency from 82% to 42% and H2S efficiency from 100% to 60%. (C) 2018 Elsevier Ltd. All rights reserved.