Analysis of Mass Transport through Anisotropic, Catalytic/Bio-Catalytic Membrane Reactors

• Published in: Catalysts Vol. 9; no. 4; p. 358
• Main Authors: Nagy, Endre, Vitai, Márta
• Format: Journal Article
• Language: English
• Published: Basel MDPI AG 01.04.2019
• Subjects: Catalysts; Chemical reactions; Convective flow; Diffusion coefficient; Diffusion layers; Diffusion rate; first-order reaction; inlet mass transfer rate; Linear equations; Mass transfer; Mass transport; Membrane reactors; Membranes; outlet mass transfer rate; Parameters; transport across anisotropic membrane; Transport processes; Transport properties; variable convective velocity; variable diffusion coefficient; Velocity; zero-order reaction
• ISSN: 2073-4344; 2073-4344
• DOI: 10.3390/catal9040358

This paper investigated the steady-state mass transport process through anisotropic, composite membrane layers with variable mass transport coefficients, such as the diffusion coefficient, convective velocity, or chemical/biochemical reaction rate constant. The transfer processes can be a solution-diffusion model or diffusive plus convective process. In the theoretical part, the concentration distribution as well as the inlet and outlet mass transfer rates’ expressions are defined for physical transport processes with variable diffusion or solubility coefficients and then that for transport processes accompanied by first- and zero-order reactions, in the presence of diffusive and convective flow, with constant and variable parameters. The variation of the transport parameters as a function of the local coordinate was defined by linear equations. It was shown that the increasing diffusion coefficient or convective flow induces much lower concentrations across the membrane layer than transport processes, with their decreasing values a function of the space coordinate. Accordingly, this can strongly affect the effect of the concentration dependent chemical/biochemical reaction. The inlet mass transfer rate can also be mostly higher when the transport parameter decreases across the anisotropic membrane layer.