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This paper aims to improve the general circuit of driving and protection based on insulated gate bipolar transistor (IGBT) in dielectric barrier discharge power supply by designing a novel half-bridge inverter circuit with discrete components.

With one SG3524 chip, the structure based on discrete components is used to design the IGBT drive circuit. The driving waveform is isolated and sent out by photo-coupler 6N137. The protection circuit is realized by Hall sensor directly detecting the main circuit current, supplemented by a few components, including diodes, resistors, capacitors and triodes. It improves the reliability of the protection circuit.

In the driving circuit, the phase difference of signals from two channels are 180°. Moreover, when the duty cycle is set at 40%, it can ensure sufficient pulse width modulation response time. In the protection circuit, when over-current occurs, an intermittent output signal is automatically sent out. Furthermore, the over-current response time can be controlled independently. The peak voltage can be adjusted continuously from 0 to 30 kV with its frequency from 8 to 25 kHz and the power output up to 150 W.

The novel circuit of driving and protection makes not only its structure simpler and easier to be realized but also key parameters, such as frequency, the duty cycle and the driving voltage, continuously adjustable. Moreover, the power supply is suitable for other discharges such as corona discharge and jet discharge.

A laboratory experiment was conducted in the soil laboratory in the Department of Environment and Environmental Pollution, Environment and Natural Resources Research Institute, National Centre for Research. The purpose of this paper is to study the movement of crude oil through soil column.

Polyvinyl chloride columns were filled with Shambat soil, amended with three concentrations of light crude oil (0.16, 0.32, and 1.28 ppm), obtained from Petrodar Oil Company. Soil samples were taken from 5 and 10 cm depths after two, 14 and 28 days from crude oil addition. At each sampling date, the recovery of petroleum hydrocarbons measured.

The results obtained indicated that high by significant differences among the different concentrations, different depths and different sampling durations. Moreover, the downward mobility of petroleum hydrocarbons decreased with increasing crude oil concentration.

Results of the experiment revealed the importance of studying the fate and mobility of total petroleum hydrocarbons (TPH) in soils in order to facilitate a proper reclamation practice specially in oil polluted sites.