Separation of Methyl Esters and Glycerol by Gravity Settling

Author : Bautista, Raul Ballelos
Major Adviser : Lozada, Ernesto P.
Committee Members : Arquiza, Apollo C.; Demafelis, Rex B. 
Year : 1993
Month : October
Type : Thesis
Degree: BS
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A batch clarifier was constructed in which methyl ester-glycerol system settling performance was evaluated. The clarifier was provided with sampling taps at different levels from which samples were drawn per one minute interval. The glycerol concentrations were analyzed and plotted against time. Analysis of variance for each sampling taps aw a class level revealed that sources of variation such as time and experimental model were significant on all sampling tap. These sources of variation declined directly at each decrease in tap height, except at lower sampling tap. Furthermore, linear regression analysis showed that the linear effect of time on the concentration weakened on lower sampling taps. The experimental terminal velocity for hindered settling of 2.9965 x 10⁻⁴ m/s was estimated from the time for the glycerol globules to settle in the batch clarifier indicated by the glycerol concentration close to 0 (0.62% by weight). The particle diameter was estimated by trial and error method, wherein the particle values were assumed and then, the values of terminal velocities for free and hindered settling were computed. The diameter value which gave a terminal velocity for hindered settling almost equal tot he experimental was considered to be the average globule diameter which was 4.57 x 10⁻⁵ m. Having found the value of particle diameter, Stokes Law criterion “K” was computed to be 0.6414 which is within Stokes Law Region (less than 2.86). Also, from Stokes Law equation, terminal velocity of 4.41 x 10⁻⁴ m/s for free settling was computed. From he data gathered, a 60 liter methyl esters capacity per batch for a clarifier was designed with D/H ratio of 1.51 and detention time of 19.10 minutes. A continuous clarifier was also designed with 60 liter methyl esters per minute capacity and feed flow rate of 0.0529 ft³/s (1.4 liters/s) wherein a detention time efficiency of 58% for D/H ratio of 1.51 were incorporated in the scale-up design to account for the effects of non-uniform flow of particles which occurred in the set-up.

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