Response surface optimization of oil extraction with agitation from Jatropha curcas L. kernels using acetone as solvent

Date

4-2010

Degree

Bachelor of Science in Chemical Engineering

College

College of Engineering and Agro-Industrial Technology (CEAT)

Adviser/Committee Chair

Monet Concepcion C. Maguyon

Committee Member

Butch G. Bataller, Jovita L. Movillon, Rex B. Demafelis

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Abstract

Crude oil was extracted from Jatropha curcas L. kernels using acetone as solvent. In the process of extraction, agitation was introduced. The effect of the agitation time and kernel-to-solvent ratio on the oil recovery was studied. Also, the operating conditions (i.E. kernel0to-solvent ratio (w/v) and agitation time) were optimized using Response Surface Methodology (RSM). The two-factor Central Composite Design was applied for this purpose. The response for this design is the oil recovery which was reported as the percentage of oil extracted from J. curcas seeds based on the maximum extractable oil obtained in this study (i.e. 50.59%). Results showed that prolonging the agitation time and decreasing the kernel-to-solvent ratio increases the percent oil recovery. The optimization was done using two approaches:(a)using one response (% oil recovery) and (b) using two responses (% oil recovery and extraction cost per mass of oil recovered). The optimum conditions were found to be 12 hours of agitation and 0.05(w/v) ratio for the first optimization approach with predicted oil recovery of 93.45%. On the other hand, the optimum conditions for the second approach were established at 4.25 hours of agitation and 0.0526 (w/v) ratio with predicted recovery of 85.21% and predicted extraction cost of about 40.15 PhP/g. The result of the cost analysis for the comparison of the two alternatives showed that the second approach should be selected because it has lower unit extraction cost as compared to 51.14PhP/g oil for the first approach. The selected optimum recovery was validated and evaluated using confirmatory experiment and "two-tailed" T-test. The confirmatory yielded an oil recovery of 84.88%. With t-value less than 63.657 and greater than -63.657, the confirmatory and the predicted values were found to have no significant difference. It was also compared with soaking carried out under the same optimal conditions as that of the second optimization approach. With soaking, the oil recovery is only 73.70% which is below the result of that with agitation. This showed that agitation gives higher oil yield in solvent extraction. It was also observed that agitation , it takes shorter time to reach the equilibrium. The solvent extracted oil with agitation was characterized in order to evaluate its viability as feedstock for biodiesel production. results showed that the oil has an acid value of 10.52mg/KOH/g, iodine value of 96.97mg I/100g, saponification value of 153.45 mg KOH/g and a specific gravity of 0.9089. Based on these analyses, refinement of the oil or the use of acid-catalyzed transesterification for biodiesel production is necessary if this acetone-extracted oil will be used.

Language

English

Location

UPLB College of Engineering and Agro-Industrial Technology

Document Type

Thesis

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