Application of pulse electron beam for NO/sub x/ removal

Abstract

To develop a new flue gas treatment device by using the pulse electron beam, an experiment of NO/sub x/ removal from the atmospheric pressure gas was performed. The pulse electron beam with energy of /spl les/160 keV, beam current of 140 A, current density of 2 A/cm/sup 2/, pulse width of 0.7 /spl mu/s and electron beam power of 12.6 J/pulse, or the electron beam with the energy of /spl les/120 keV, 10 A, 2.5 /spl mu/s and 2.8 J/pulse was injected into the gas cell filled with atmospheric pressure NO/N/sub 2/ or NO/N/sub 2/+O/sub 2/(20%) gas. When the electron beam of 12.6 J/pulse was injected into NO(=200 ppm)/N/sub 2/ gas, twenty percent of NO was removed by one pulse and 90% by 8 pulses with the efficiency of 180 nmol/J (=58 eV/molecule) in the gas cell of 1.7l. The efficiency depended on the removal ratio, the volume of the gas cell, initial NO concentration and the electron beam power. Efficiencies of 370 nmol/J at the removal ratio of 50% in relatively large gas cell of 6.2 l, 580 nmol/J for large NO (=2000 ppm) concentration at the ratio of 20% and 527 nmol/J for long pulse (2.5 /spl mu/s), 2.8 J/pulse of electron beam injection were obtained. When the electron beam was injected into the gas mixture of NO (=200 ppm)/N/sub 2/ with O/sub 2/(20%), the oxidization of NO to NO/sub 2/ was highly activated. When the water was added to the gas mixture, NO/sub x/ was removed through the process of nitric acid production. When the wall of the gas cell was covered with the wet cloth and the pulse electron beam was injected, NO/sub x/ of 40% was removed by the process of acid production and the absorption of NO/sub 2/ into the wet cloth with the total efficiency of 570 nmol/J. When NH/sub 3/ was added by the ratio of NH/sub 3/:NO=1:1, NO/sub x/ of 95% was removed with efficiency of 160 nmol/J.