NOx removal with multiple pulsed electron beam free of catalysts or reagents

Abstract

A catalyst free approach for nitrogen oxides (NO_x) removal has been developed at the United States Naval Research Laboratory. Our goals were to assess the ability of pulsed electron beam to enhance NO_x removal at potential lower capital cost with greater efficiency than other large scale NO_x removal methods. Removal efficiency over 95% has been attained for NO_x concentrations of 1000 parts per million (ppm), 500 ppm and 200 ppm in nitrogen atmosphere. The NO_x concentration dropped from 204 ppm to below 4.8 ppm after 10 shots supplying a total dose of 65 kGy. The resultant chemicals after catalyst free pulsed electron beam processing of NO_x are nitrogen and oxygen, same as components of air. Pulsed electron beams in a catalyst free approach remove a larger percentage of NO_x than continuous wave electron beam with a catalyst. Catalyst free approach removes issues of handling, collecting, transporting and efficiently distributing chemical byproducts. Pulsed electron beams are as efficient as continuous wave electron beams for small removal percentages and have a significant advantage at higher fractional removal percentages of NO_x. Preferential destruction of NO species relative to the removal of NO₂ species is observed in the pulsed electron beam reaction chamber. The energy required to remove a kilogram of NO_x is nearly the same at pressures of 1.16 atmospheres and 1.02 atmospheres.