Development of removal Apparatuses of Exhausted Gases by Using Microwave Discharge and Photochemical Processes

在NO和N_2流量分别为10和1000 sccm的条件下，研究了微波吸收剂辅助放电NO/N_2混合气体脱除NO的特性。在50 Torr以上的高N_2气压下，不使用微波吸收剂不能维持放电，但使用石墨、锆、钨棒等微波吸收剂，可以在大气压下维持稳定的微波放电。将一根长棒或两根短棒的吸收剂插入微波腔的中心。采用两根催化棒的NO转化率高于单根催化棒，但前者的CO、CO_2、ZrO_2和WO_3等氧化物的支化率较高。用193 amArF准分子激光器在N_2和空气中进行了光化学去除N_2O和NO_2的实验研究。在100 mJ/pulse的激光功率下，当N_2O浓度为100 ppm时，激光照射15 mm后，N_2O几乎完全转化为N_2和O_2，没有NOx排放。实验结果和计算值之间的合理协议，表明我们的模型计算是有效的。在NO_2浓度为240-3000 ppm范围内，激光功率为80 mJ/pulse时，NO_2在N_2和空气中均能有效地转化为N_2、O_2和NO，其N_2：NO的相对生成比分别为1：0.38 ± 0.79和1：0.41 ± 0.63。在100 ppm的低NO_2压力下，NO_2在空气中被完全氧化为N_2O_5。在此低NO_2压力范围内，由于O_3的影响，NO_2在空气中的主要转化过程是由NO_3氧化成N_2O_5。

The NO removal by a microwave-absorbent assisted discharge of an NO/N_2 mixture has been studied at NO and N_2 flow rates of 10 and 1000 sccm, respectively. Although discharge could be not be maintained at high N_2 pressure above 50 Torr without using microwave absorbents, stable microwave discharge could be maintained at an atmospheric pressure by using such a microwave absorbent as graphite, Zr, or W rod. One long rod or two short rods of absorbents were inserted into the center of the microwave cavity. Conversion of NO obtained by using two rods was higher than that by using one rod, though the branching ratios of such oxides as CO, CO_2, ZrO_2, and WO_3 were higher in the former case. A high NO conversion of 97% was achieved by using two short rods of graphite.Photochemical removal of N_2O and NO_2 by 193 am ArF excimer laser has been investigated in N_2 or air at atmospheric pressure. N2_O was nearly completely converted to N_2 and O_2 without NOx emission in N_2 and air at a low N_2O concentration of 100 ppm after laser irradiation for 15 mm at a laser power of 100 mJ/pulse. A reasonable agreement was found between experimental results and calculated values, indicating that our model calculation was valid. NO_2 was efficiently converted into N_2, O_2, and NO in N_2 or air in the NO_2 concentration range of 240-3000 ppm at a laser power of 80 mJ/pulse, and the relative formation ratios of N_2:NO in N_2 and air were 1:0.38〜0.79 and 1:0.41〜0.63, respectively. NO_2 was completely oxidized into N_2O_5 in air at low NO_2 pressure of 100 ppm. The major conversion process in air in this low NO_2 pressure range was oxidation of NO_2 into N_2O_5 via NO_3 due to effects of O_3.