Intensificação do processo de separação de biodiesel com membranas de fluoreto de polivinilideno (PVDF)

Abstract

Considering the alternative sources of biofuels available, biodiesel production has a prominent place in postmodern society. Industrially, transesterification is the most used reaction to obtain biodiesel, obtaining fatty acid esters (biodiesel) and glycerol, as products. Due to the presence of glycerol, additional purification processes are necessary, which cause an increase in costs and production time for the final purified biodiesel, in addition to generating large volumes of effluents. Therefore, the application of membrane separation processes (MSP) has attracted considerable attention and is a very promising area. The process has high separation efficiency, is environmentally safe, requires little energy expenditure and is operationally simple and flexible. In this context, this work aims to evaluate the applicability of membrane separation process in biodiesel purification by formulating blendsthat simulate its composition, containing oleic acid, ethyl ester, ethyl alcohol and glycerin, and with subsequent separation using ultrafiltration polymeric membranes made of polyvinylidene fluoride (PVDF). To perform the experiments, a benchtop permeation module was developed and used to separate the blends, making it possible to determine the retention percentage of the hollow fiber membranes against blends of components of known concentrations. The theoretical hydraulic permeability of the module was 226.34 L/h.m2 .bar. The rejection tests demonstrated good efficiency in the separation of solutes with higher molar mass. The morphology observed by SEM allowed determining the internal diameter (0.813 mm) and external diameter (1.780 mm) of the fibers, and also demonstrated that the membrane has a well-formed structure with good pore distribution. The maximum retention values obtained were 92.07% with the presence of oleic acid in the blend, and 95.50% with the presence of ethyl oleate. The use of membrane separation technology is technically viable for application in biodiesel separation process. However, further research is needed to investigate and define the best operating conditions for the system.