Corona and back discharges in flue-gas simulating mixture

Results of spectroscopic investigations and current–voltage characteristics of electrical discharges between a needle and plate electrodes in a gas mixture simulating flue gases from coal fired power plants at atmospheric pressure are presented in the paper. In these investigations, back discharge was generated at the plate electrode covered with fly ash layer in order to simulate the conditions similar to those in electrostatic precipitators. To characterize the physical processes in back discharges, the emission spectra were measured and compared with those obtained for normal corona discharge generated in the same electrode configuration but with fly ash removed from the electrode. The emission spectra provide information on elemental and molecular composition of the layer. It was also shown that discharge characteristics in flue gas are quite different from those occurring in ambient air.

► Back discharge from fly ash layer in flue gas has been investigated.
► Current voltage characteristics of back discharge in flue gas have been measured.
► Light emission spectra of corona and back discharges in flue gas were recorded.
► Spectral lines of fly ash elements appear in emission spectra of back discharge.
► Back discharge characteristics in flue gas are quite different from those in air.