Abstract
This thesis presents an initial investigation of using electrostatic coalescence as an alternative to conventional separation processes to purify used automotive crankcase oil. Specific emphasis of this study was the feasibility of this approach, verified by separating and analyzing a used oil emulsion. The metal removal efficiency was compared to that of a five day gravity settling. Separation experiments were performed in a 2.26 L coalescer with a flat parallel insulated electrode configuration. The used oil emulsion, composed of used oil, Isopar M, and water (no noticeable phase separation for 12 hours) followed the electrostatic coalescence characteristic of higher applied voltages or frequencies allowing higher feed rates. Metal removal efficiencies for iron, calcium and zinc were 3.57, 47.1, and 46.7 %, respectively, using Nalco 7715 at a peak a.c. voltage of 7 kV/cm and a frequency of 1000 Hz at the maximum rate of coalescence. For gravity settlement, metal removal efficiencies for iron, calcium and zinc were 11.2, 15.6, and 57.1 %, respectively. Considering the residence time of a moderate emulsion feed rate is a fraction of an hour, electrostatic coalescence offers an advantage over gravity settling. Oil phase water content varied between 0.05 and 7.2 wt %.
Dixon, John Leslie (1998). Electrostatic coalescence of used automotive crankcase oil as an alternative to other separation processes. Master's thesis, Texas A&M University. Available electronically from
https : / /hdl .handle .net /1969 .1 /ETD -TAMU -1998 -THESIS -D59.