Dielectric Relaxation-Based Capacitive Heating of Oil Sands

By Tinu Abraham and C. W. Van Neste and Artin Afacan and Thomas Thundat
Published in Energy & Fuels NULL 2016

Abstract

An electrothermal method of capacitive heating of oil sands was investigated. Temperature-based impedance spectroscopy experiments for a given rich grade of oil sands were conducted to identify a suitable dielectric relaxation frequency for carrying out capacitive heating, which was observed to be around 65 kHz having a full width at half-maximum of two decades. This was attributed to interfacial polarizations at water, bitumen, and silicate mineral interfaces. The relaxation frequency changed with temperature rise, indicating that frequency tuning could be suitable to optimize capacitive heating. Hence, capacitive heating of oil sands was demonstrated by exposing it to high alternating electric fields (104 V/m) at a frequency in the dispersion regime of its relaxation frequency. As temperature increased, the overall impedance of oil sands decreased as determined from impedance spectroscopy. Frequency was retuned to match the changed impedance of the system, which ensured that temperature further increased.

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