Comparison of Reactor Type for Pollution Control by Using the Pulsed Corona Discharge

Abstract

The removal of harmful nitrogen oxides (NOx) and sulfur oxides (SOx) have become an important issue because they do considerable harm to human and cause acid rain. Disposal of these flue gases (NOx and SOx) has been performed by flue gas desulfurization (FGD) and selective catalytic reduction (SGR) but these methods have many problems they used too much catalyst and generated secondary contamination. In 1970`s, electron beam, dielectric barrier discharge and pulsed corona discharge were studied as new methods; they have both advantages and disadvantages. Recently, study on the pulsed corona discharge has progressed because of simplicity and efficiency of the system. The pulsed corona discharge is an electrical conduction phenomenon of gas, composed of many streamer channels. Generally a streamer with strong space charge has 1 s of burning time, 1ns of repetition cycle and 20 m of diameter in air at standard condition (1atm of pressure, 0℃ of temperature), and its characteristics is significantly influenced by the composition of discharging gas, applied voltage, and the gas pressure, etc. Especially the density and the distribution of streamers vary with the amplitude and the shape of applied voltage, and the electrode geometry. Nevertheless, these phenomena are not well analyzed due to complexity of simulations and diagnosis. It is the purpose of this work to measure efficiency of removal of NO and NOx for applied voltage, repetition frequency and energy according to reactor type (wire-plate and wire-cylinder type reactor) for optimization of the reactor. Characteristics of Reactor type by pulsed corona discharge can be analyzed through these results. In this work, efficiency of removal of NO and NOx was investigated in terms of applied voltage, repetition frequency and energy compared wire-plate type reactor with wire-cylinder type reactor which are using by pulsed corona discharges. Because it is very difficult to measure the conduction current for corona discharge, conduction current was measured indirectly, which is for calculation of energy transferred into the reactor, and from this, the necessary energy for removal of NO and NOx was calculated. Removal efficiency of NO and NOx of the wire-cylinder type reactor for various parameters such as applied voltage, pulse repetition frequency, energy transferred into the reactor and removed quantity etc. is calculate as higher than that of the wire-plate type reactor.

# Work supported by the Electrical Engineering and Science Research Institute of Korea and the National Research Laboratory Project of the Korea Institute of Science and Technology Evaluation and Planning under Ministry of Science and Technology of Korea.