NOx treatment using low-energy secondary emission electron gun

A compact and highly efficient broad electron-beam source that is capable of reducing a wide range of gaseous pollutants that are very much demanding for environmental applications. We are developing an ion-induced secondary-emission electron gun (SEEG) using wire ion-plasma source for environmental applications such as NO_x treatment. The SEEG offers uniform and large cross section electron beams suitable for the efficient reduction of gaseous pollutants. We present the first report about the application of SEEG on NO_x treatment. The performance of SEEG on NO_x treatment is quantitatively related to removal ratio and removal efficiency of 250 ppm of NO in N₂. The electron-beam irradiation was carried out in a gas treatment chamber (13 L), where the sample flue gas was flown in ambient pressure and temperature at a controlled volumetric flow rate of 2 to 14 standard liters per minute. The NO removal characteristics have been studied under various conditions such as increased gun voltage, gas flow rate, and varied pulsed-electron-beam parameters (current density and pulse length). A reasonable NO removal ratio of 20% was achieved in 60 s (repetition rate = 10 pps, current density = 28 mA/cm², and pulse length = 10 μs) at the accelerating gun voltage of 100 kV. The NO removal efficiency expressed in terms of specific energy cost for NO removal is 63.15 eV/molecule. It was observed that temporal and spatial characteristics of pulsed electron beam impose a substantial effect on the NO removal and the processing efficiency. We are trying to increase the processing efficiency by reducing treatment-chamber dimensions and applying a number of well-optimized parameters.