Karakterisasi emulsi air dalam bensin dengan campuran sorbitan monooleat (Span 80) dan polioksietilena sorbitan monooleat (Tween 80) sebagai emulgator
SUHARTOYO, Dr. Triyono, SU
2009 | Tesis | S2 Ilmu KimiaTelah dilakukan karakterisasi emulsi air dalam bensin dengan campuran sorbitan monooleat (Span 80) dan polioksietilena sorbitan monooleat (Tween 80) sebagai emulgator. Penelitian diawali dengan menentukan rasio volume Span 80/ Tween 80 yang dapat menghasilkan emulsi air/bensin yang optimal. Penentuan fraksi volume emulsi air/bensin yang terbentuk dilakukan pada berbagai persen volume air, bensin dan campuran Span 80/Tween 80. Kelakuan fasa emulsi air/bensin direpresentasikan dalam diagram campuran tiga komponen. Uji karakter dilakukan terhadap emulsi air/bensin meliputi penentuan berat jenis, viskositas, tegangan permukaan, titik didih awal (initial boiling point), tekanan uap dan kalor pembakaran dilakukan berturut-turut dengan metode hidrometer (hydrometer), viskometer Ostwald, pipa kapiler, refluks, tekanan uap (Reid vapor pressure, ASTM D 323) dan kalorimeter bom (bomb calorimeter). Rasio Span 80/Tween 80 yang optimal adalah 6/4 (v/v) dimana komposisi volume air/bensin = 2/8 dapat teremulsi seluruhnya membentuk satu fasa 100 % volume emulsi air/bensin dengan penambahan campuran Span 80/Tween 80 sebanyak 9,1 % volume campuran pada 27 °C, sedangkan pada komposisi volume air/bensin = 3/7, persentase volume emulsi air/bensin maksimal yang diperoleh adalah 96,4 %. Berat jenis dan viskositas emulsi air/bensin semakin tinggi dengan bertambahnya jumlah air dan jumlah campuran Span 80/Tween 80 dalam campuran. Setelah tercapai titik kritis misel tegangan muka turun sekitar 42 s.d. 45 dyne/cm. Titik didih dan tekanan uap emulsi air/bensin dipengaruhi oleh banyaknya komponen masing-masing antara air, bensin dan campuran Span 80/Tween 80 dalam sistem emulsi. Titik didih emulsi air/bensin berkisar diantara titik didih bensin, sementara besarnya tekanan uap sedikit dibawah tekanan uap bensin. Kalor pembakaran bahan bakar emulsi semakin berkurang seiring meningkatnya jumlah air atau jumlah campuran Span 80/Tween 80. Pada komposisi volume air-bensin-Span 80/Tween 80 adalah 9,1% - 81,8% - 9,1% diperoleh kalor pembakaran sebesar 8904,63 kalori/gram, sementara kalor pembakaran bensin premium murni adalah 10432,77 kalori/gram.
Characterization of water-in-gasoline emulsion with mixed sorbitan monooleate (Span 80) and polyoxyethylene sorbitan monooleate (Tween 80) as emulsifier has been investigated. The research was begun by determination of volume ratio Span 80/Tween 80 that can produce optimally water-in-gasoline emulsion. Determining of the volume faction of water in gasoline emulsion was done at various volume percent of water, gasoline and mixed Span 80/Tween 80. Phase behavior of water-in-gasoline emulsion was represented by pseudoternary phase diagram. Test of characters were carried out on water-in-gasoline emulsion include the determination of density, viscosity, surface tension, initial boiling point, vapor pressure and heat of combustion done in succession with hydrometer, viscometer Ostwald, capillary pipe, reflux, Reid vapor pressure (ASTM D 323), and bomb calorimeter. The best volume ratio of Span 80/Tween 80 was 6/4, in which the volume composition of water/gasoline = 2/8 can be formed entirely as one phase 100% volume water-in-gasoline emulsion with the addition mixture of Span 80/Tween 80 as much as 9.1% volume of the mixture at 27 °C, while the volume composition of water/gasoline = 3/7, the maximum of volume percentage of water-in-gasoline emulsion is 96.4%. Specific gravity and viscosity of water-ingasoline emulsion are higher with increasing in the amount of mixed Span 80/Tween 80 and the amount of water in the mixture. After the critical micelle concentration was reached the surface tension was down in the range of 42 to 45 dyne/cm. The initial boiling point and the vapor pressure of water-in-oil emulsion were influenced by many components of each of water, gasoline and mixed of Span 80/Tween 80 in emulsion system. The range of initial boiling point of waterin- gasoline emulsion was around of initial boiling point gasoline, while the vapor pressure was slightly under the vapor pressure of gasoline. Heat of combustion of emulsion fuel was decrease with increase in the amount of water and the amount of mixed Span 80/Tween 80. When the volume composition of each watergasoline- Span 80/Tween 80 was 9.1 - 81.8 - 9.1%, the heat of combustion was 8904.63 calories/g, while heat of combustion of pure natural gasoline was 10432.77 calories/g.
Kata Kunci : Emulsi air/bensin,Campuran span 80/tween 80,Karakter emulsi air/bensin, Water-in-gasoline emulsion; mixed Span 80/Tween 80; characters of water-in-gasoline emulsion
