High power short duration pulse generator for SOx and NOx removal

Radical formation for oxidation and subsequent removal of SO/sub 2/ and NO in flue gases from coal and oil-fired boilers requires pulses of high amplitude and short duration. The inherent electrostatic capacitance of a reactor with an electrode arrangement similar to that of an electrostatic precipitator necessitates that a generator with low internal inductance and high switched power be used. The author describes the development, design, and construction of a pulse generator for application on a 3 nF prototype reactor with wire-to-plate geometry. The specification called for the generation of a 100 kV pulse with a rise-time of 100 ns. Measurements indicated a typical pulse rise-time of 120 ns, i.e. 20% longer than specified. A reason is that the load capacitance was 3.6 nF instead of 3.0 nF due to stray capacitance. The pulse generator was constructed as a two-stage Marx generator with rotating spark gaps, and measurements showed that the attained values were close to specifications.<>