Evaluation of mass transfer resistance across the interface for CO2–propylene carbonate system: experimental and mathematical modeling

• Published in: Chemical engineering research & design Vol. 149; pp. 34 - 44
• Main Author: Azizi, Shima
• Format: Journal Article
• Language: English
• Published: Rugby Elsevier B.V 01.09.2019; Elsevier Science Ltd
• Subjects: Algorithms; Boundary conditions; Carbon dioxide; Decay; Diffusion; Diffusivity; Finite difference method; Gas flow; Henrys law; Initial pressure; Mass transfer; Mass transfer resistance; Mathematical modeling; Mathematical models; Molecular diffusivity; Numerical analysis; Physical chemistry; Polypropylene; Pressure decay method; Propylene; Propylene carbonate; Solubility; Molecular diffusivity; Mathematical modeling; Mass transfer resistance; Pressure decay method; Propylene carbonate; Carbon dioxide
• ISSN: 0263-8762; 1744-3563
• DOI: 10.1016/j.cherd.2019.07.005

•Pressure decay and solubility data were obtained for CO2–propylene carbonate system.•Experimental data used to obtain diffusivity at different temperatures and pressures.•Two models were established regarding to the interfacial mass transfer resistance.•Mass transfer parameters were obtained comparing experimental and model data.•Mass transfer resistance was evaluated across the interface. In this work, solubility and diffusivity of CO2 in propylene carbonate have been experimentally obtained using the pressure decay method. Pressure decay data were produced at three different temperatures of 276.15, 298.15, and 328.15K, and different initial pressures. The tests were conducted with and without mechanical stirrer to obtain solubility and diffusivity, respectively. The solubility data showed that CO2–propylene carbonate system properly obeys the Henry’s law. To evaluate the diffusivity, two different mathematical models according to the types of boundary condition at the interface were established and a novel finite difference-assisted algorithm was developed to solve the parabolic equations. The molecular diffusivity was then obtained as a tuning parameter by comparing the results of mathematical model and the experimental pressure decay data. Results showed that for the system of CO2–propylene carbonate, the performance of both mathematical models were nearly the same, hence, the mole fractions at the interface properly obey the equilibrium curve. Therefore, it was concluded that the mass transfer resistance across the interface was negligible. It was proved that the proposed numerical algorithm produced an unconditionally stable solution. Furthermore, it was shown that the diffusivity increased with increasing temperature and decreased with increasing initial pressure.