Theory of Chemical ProcessingUsing Pulsed Precipitators

Abstract

A theoretical analysis is given, using methods of gaseous electronics and plasma chemistry, of the removal of S02 and nitrogen oxides from flue gases by use of pulsed electrical corona. Calculations indicate that the rate coefficients in a typical flue gas for the electron dissociation of nitrogen, oxygen and water vapour only become appreciable for values of E/N greater than about 80 Td; E is electric field strength and N the gas number density. Chemical calculations using these data indicate that 802 is removed by conversion to sulphuric acid by reactions with OH radicals, and that oxides of nitrogen are removed largely by reduction from N atoms. To attain these high values of E / N, it is necessary to use pulsed voltages of pulse width r-v1 us in order to avoid electrical breakdown. The maximum pulse widths allowable to avoid breakdown is estimated by requiring the total energy input to be less than that which heatsthe gas by 104 K.