Análise da fluidodinâmica computacional num processo de dessalinização por osmose reversa
Ricelly Fernandes Santos
UFERSA
Diego David Silva Diniz
Jackson De Brito Simões
Gilsomaro Barbosa de Melo Silva
Palavras-chave: Analysis of computational fluid dynamics in a reverse osmosis desalination process
Resumo
For decades, the lack of water has been a problem that affects humanity, and in recent years, this problem has become even more serious due to global warming, population growth and increased droughts. Therefore, desalination processes have emerged as important alternatives for the production of drinking water around the world. Several technologies are used in these processes, being the reverse osmosis desalination (RO) technique, with membrane separation, highlighted as a promising technology, due to its high ability to separate a solvent (water), from a solute that has low molecular mass (salts), as well as for having high energy efficiency, easy maintenance, lower area occupation and good cost-benefit ratio. However, one of the main disadvantages regarding the use of this technique is that the membrane is susceptible to incrustations, which causes a reduction in permeated flow, increased operating pressure, inadequate selectivity, reduced membrane life and increased operating costs. Given this assumption, the objective of this work is to present a computational modeling study focusing on the optimization of the membrane separation process via reverse osmosis, through analysis of the geometry of the permeation module and the effects of the movement of turbulence promoters. With this, we sought to generate beneficial turbulence in the flow in order to increase the shear rate in the vicinity of the membrane interface and, thus, reduce the mass fraction of the solute in the regions neighboring the membrane surface. For this, numerical simulations were performed with mathematical models capable of understanding the behavior of the phenomena present in the process of membrane separation via RO. The mathematical model used to perform the simulations was based on the equations that mass conservation, momentum, species transport and the Spiegler and Kendem model. All simulations were performed using the ANSYS FLUENT and ICEM CFD software. The geometry model used in these simulations was the one with the domain of circular spacers. The results of the simulations showed an efficient representation of the transfer phenomena involved in the process of separation by reverse osmosis. In addition, these results allowed a thorough analysis of the behavior of a fluid under the action of moving turbulence promoters, highlighting that the spacers for the case studied increased the turbulence at the site due to its movement, causing the salt concentration layer to disperse to the neighborhood, causing a cleaning in the membrane.