Eventos Anais de eventos
CONEM 2022
XI Congresso Nacional de Engenharia Mecânica - CONEM 2022
INFLUENCE OF MEMBRANE EFFECTIVE THERMAL CONDUCTIVITY AND TORTUOSITY MODELS ON THE PERFORMANCE OF DCMD SYSTEMS FOR DESALINATION
Submission Author:
Ingrid Curcino , RJ
Co-Authors:
Ingrid Curcino, Paulo Roberto Siqueira da Costa Júnior, Abdul Orlando Cárdenas Gómez, Elena Peñaranda, Joao Alves de Lima, Carolina Palma Naveira Cotta, Renato Machado Cotta
Presenter: Ingrid Curcino
doi://10.26678/ABCM.CONEM2022.CON22-0125
Abstract
The Direct Contact Membrane Distillation (DCMD) is a thermally driven membrane separation process pointed out as a promising alternative for seawater desalination from low exergy waste heat recovery. The development of proper mathematical models for describing the effects of the characteristics of microporous and hydrophobic membranes, which act as a non-wetting barrier in the membrane distillation (MD) process, is necessary for a robust analysis of the process. This study aims to analyze membrane effective thermal conductivity (resistances in parallel, series, and Maxwell I) and tortuosity (Euclidian and fractal approaches) models that can be used to calculate membrane effective and morphological properties. For this purpose, simulated values of distillate mass flux were obtained from the numerical solution of 2D and 3D models that incorporate the morphological and interfacial membrane characteristics in the heat and mass transfer of the MD process using a multi-region approach with OpenFOAM. The predicted values were validated by comparison with experimental data from the literature for the DCMD configuration, PVDF membrane with different morphological characteristics, and flat and hollow fiber geometries. The results suggested that the morphology of the membranes influences the selection of the models for membrane effective thermal conductivity and tortuosity. For the membrane with sponge-like morphology, the combination of the parallel-resistance model for the effective thermal conductivity and the fractal tortuosity model based on the random distribution of spheres provided an RMSE (root mean square error) concerning the experimental data of 0.7 kg/(m2.h). On the other hand, for the membrane with an asymmetric pore distribution and macro voids in its the cross-section (finger-like channels), it was found that the combination of the parallel-resistance model for effective thermal conductivity and the Euclidian tortuosity model for the random arrangement of highly interconnected pores provided the highest agreement between experimental and theoretical data, presenting RMSE of 1.4 kg/(m2.h) regarding the experimental data.
Keywords
Direct contact membrane distillation, membrane effective thermal conductivity, membrane tortuosity, Computational simulation
