Nelson Medeiros de Lima Filho

Selection of a stationary phase for the chromatographic separation of organic acids obtained from bioglycerol oxidation

A screening study of the chromatographic separation of Glyceric Acid (GCA) and Tartronic Acid (TTA) was performed using three different polystyrene-divinylbenzene ion-exchange resins in hydrogen form (Dowex® 50WX-8, Dowex® 50WX-4, Dowex® 50WX-2). The experiments were described by the axial dispersion flow model with the LDF approximation incorporated into the software gPROMS. From the three investigated adsorbents differing by the crosslinking, Dowex® 50WX-2 has presented the higher adsorption capacity, as well as the highest bed efficiency expressed by the number of theoretical plates. The adsorption equilibrium constants were determined from single breakthrough experiments, and a very good agreement between experimental and simulated data was achieved for both single components and binary mixtures. Therefore, the fundamental data determined within this work represents a key contribution to the design of continuous chromatographic processes for the purification of GCA and TTA.

Produção de Biodiesel Metílico com Óleo Purificado de Moringa oleifera Lamarck

This study describes the extraction, characterisation, purification and conversion of the Moringa oleifera Lamarck oil in biodiesel. The seeds selected were separated into oilseeds grains and seed husks. The oil was extracted from the Moringa oleifera seeds using two different procedures: mechanical pressing and solvent extraction with hexane. The extraction yields of the crude oil were of 11.36% (by mechanical pressing) and of 36.48% (by solvent extraction), respectively. The crude oils were characterised in indexes of acidity, peroxide, iodine and saponification, besides the specific mass, kinematic viscosity, turbidity, and contents of ash and humidity. The crude oil mix formed was submitted to the treatments of degumming, neutralisation, washing and drying. The mixed purified oil was characterised in a similar way to the crude oils, and converted to methyl biodiesel. A homogeneous alkaline transesterification used, 1:6 molar ratio (oil: methanol), at 60 o C, for 60 mins, with KOH as catalyst and mechanical stirring at 300 rpm. The purified biodiesel was characterised in terms of specific mass (869 kg m -3 ; 20 o C), kinematic viscosity (5.5 mm 2 s -1 , 40 o C), ester content (86.2%, in bench scale, and 98.23% in microscale), acidity value (0.43 mg KOH g -1 ) and water content (615.8 mg kg -1 ). DOI: 10.5935/1984-6835.20160063

Separation of tartronic and glyceric acids by simulated moving bed chromatography

The SMB unit developed by the Laboratory of Separation and Reaction Engineering (FlexSMB-LSRE®) was used to perform tartronic acid (TTA) and glyceric acid (GCA) separation and to validate the mathematical model in order to determine the optimum operating parameters of an industrial unit. The purity of the raffinate and extract streams in the experiments performed were 80% and 100%, respectively. The TTA and GCA productivities were 79 and 115 kg per liter of adsorbent per day, respectively and only 0.50 cubic meters of desorbent were required per kilogram of products. Under the optimum operating conditions, which were determined through an extensive simulation study based on the mathematical model developed to predict the performance of a real SMB unit, it was possible to achieve a productivity of 86 kg of TTA and 176 kg of GCA per cubic meter of adsorbent per day (considering the typical commercial purity value of 97% for both compounds) with an eluent consumption of 0.30 cubic meters per kilogram of products.