PENGARUH KECEPATAN SENTRIFUGASI TERHADAP KEMURNIAN GLISEROL SEBAGAI HASIL SAMPING PEMBUATAN BIODIESEL DARI MINYAK GORENG BEKAS (The Influence of Speed Centrifugation About Preserving The Purity of Glycerol as a By-Product In The Manufacture of Biodiesel from Waste Cooking Oil)

Abstract

Waste cooking oil is an oil that has been used more than two or three times in a frying pan, and can be categorized as a waste as it can damage the environment and may cause a number of diseases. Waste cooking oil can be manufactured into biodiesel through esterification-transesterification reaction, from making the results biodiesel produced a by-product in the form of glycerol. The process of separation of the methyl ester-glycerol that is used is a comparison of two methods, namely the method of centrifugation and settling method. Methods of deposition or settling method takes a long time due to the gravitational force that needed to be countered by diffusion and Brownian motion style of globula-globula in suspension. Centrifugation method using the principle by which the object is rotated horizontally on a certain distance. If the object is rotating inside a tube or cylinder containing a mixture of fluids and particles, then the mixture can move towards the rotation, but this did not happen due to an opposing force that leads toward the outer wall of the cylinder or a tube according to the weight of each type of particle, the style is centrifugal force. In this practice, on the method of settling the methyl ester-glycerol sample settling for 12 hours to separate the methyl ester and glycerol, whereas with centrifugation method, a method used to increase the rate of deposition by delivering on style particles-centrifugation is partially. Changed variable used is the speed centrifuge gemmy PLC-03 with a scale of 2, 3, 4, 5, and 6 (1250 rpm, 1375 rpm, rpm, rpm-1477, 1772 and 1775 rpm) and lap time of 20 minutes. The separation method of settling method and centrifugation method obtained the best separation method is centrifugation method due to the acquisition of glycerol and surface tension of the glycerol produced is best. On the method of centrifugation separation methyl ester-glycerol obtained optimal rotational speed is 1772 rpm. Key words: centrifuge, settling, methyl ester, glycerol