Laser-Induced Voltage of Oil Shale for Characterizing the Oil Yield

The oil yields of oil shales from the Longkou, Yaojie, and Barkol districts in China were characterized with laser-induced voltage, which was monitored by a voltage tester or a digital oscilloscope when oil shale was irradiated directly by a continuum solid-state laser with a wavelength of 532 nm without an applied bias or at a bias of 9 V. The laser-induced voltage strongly depends upon the properties of the oil shales and exhibits an increasing trend as the oil yield increases from ∼5.66, 9.05, to 14.16% for Barkol, Yaojie, and Longkou, respectively. In addition, the rise time constant increases with the decrease of the oil yield, while the fall time constant declines as the oil yield decreases. A possible mechanism was proposed by the comparative analysis of the experimental results. The experimental results provide useful optical information on oil shale, suggesting the laser-induced voltage can be used to characterize the oil yield of oil shale.