Using monatomic nitrogen induced by a pulsed arc to remove nitrogen oxides from a gas stream

摘要

The effectiveness of monatomic nitrogen, induced by a pulsed electric arc, in reducing nitric oxide (NO) and nitrogen dioxide (NO2) was studied. The goal for this research is the reduction of nitrogen oxides (NOx) from automobile emissions by this alternative technique, which can be cost-effective (to be demonstrated in the near future) and has the potential to reduce NOx in exhaust containing up to 10% oxygen. The initial tests with 100, 500, and 1,000 ppm NO in pure nitrogen have shown that a greater than 50% reduction of NO/NOx is readily achievable. Different flow rates of the monatomic nitrogen and the gas stream were tested. The flow rate of the monatomic nitrogen did not have a significant effect on the reduction efficiency, unlike the flow rate of the gas stream. The cross-sectional flow area of the gas stream was varied in order to assess whether the proximity of the gas stream to the arc would affect NO/NOx reduction. Results of the tests revealed that the smallest cross-sectional area gave the best reduction, but it also had the greatest chance of contacting the arc. The composition of the gas stream was also varied to elucidate the effects of NO2 and O2 on the NO/NOx reduction efficiency. When NO2 and O2 are present in the gas stream, both gases lower the reduction efficiency significantly by creating more NO or NO2. Experiments are continuing to improve the reduction efficiency. The electrical power, a function of pulse frequency, voltage, and current, was treated as a key parameter in the investigation. The power consumption of the high-voltage pulser apparatus for a 100-kW engine was estimated to be 3 kW.