PULSED PLASMA PROCESS FOR FLUE GAS REMOVAL FROM AN INDUSTRIAL INCINERATOR BY USING A PEAK 200-KV, 10-KA PULSE MODULATOR

Abstract

The electrical discharge process, especially the pulsed plasma discharge process can be applied to the removal of pollutant gases from industrial plants such as power generation plants and incinerators. Up to now, most of the study has been performed in a laboratory scale with short-term tests due to the lack of a reliable pulse modulator with a high average power. The pulsed corona discharge method shows encouraging results for the removal of NOx and SO2 gases based on small-scale experiments. A 120-kW high average power modulator for industrial applications of the pulsed corona process to remove flue gas has been designed and manufactured. It is one of the largest scale modulator systems in the world for treating NOx and SO2 simultaneously. Its design specifications are as follows: an average power of 120 kW, a peak voltage of 200 kV with a full width at half maximum (FWHM) of 500 nsec, a peak current of 10 kA, and a pulse repetition rate of 300 Hz. It is required to have long lifetime and high reliability for commercial plant application because the downtime for maintenance affects plant availability. A high-power, fast semiconductor switch, a magnetic-pulse-compression (MPC) switch, and a fast-pulse transformer are essential components to meet these requirements. The 120-kW high average power modulator has been installed and tested at an industrial incinerator plant with a gas flow of 50,000 Nm(3)/Hr. This modulator was operated with pulses of up to 150 kV with 500-nsec (FWHM) pulse widths at a 240-Hz repetition rate in a plasma reactor. This paper presents the design details and operational test results. Especially, the dynamic operating characteristics of the MPC modulator combined with the non-thermal plasma reactor were measured, and the SO2 and NOx removal characteristics were analyzed.