Fe_(2)O_(3)和MnO_(2)催化半焦燃烧与脱硝的试验研究

Combination of catalytic combustion and catalytic denitration of semi-coke with Fe_(2)O_(3) and MnO_(2)

研究Fe_(2)O_(3)和MnO_(2)两种添加剂对半焦燃烧过程的影响,使用热重分析仪(TGA)测定了在100~900℃下半焦的燃烧特性。利用氮气吸附法(BET/BJH)测定了半焦灰渣的结构参数,并通过扫描电镜(SEM)观察其表面形貌。利用X射线光电子能谱(XPS)测定其表面离子浓度。结果表明,当分别添加5%Fe_(2)O_(3)和5%MnO_(2)时,半焦着火温度分别增加了9.04℃和13.55℃,燃尽时间分别缩短22.62 s和54.18 s,NO生成量分别下降了49%和36%,CO生成量分别下降10%和18%。然而,加入5%Fe_(2)O_(3)-5%MnO_(2)复合添加剂,半焦着火温度降低了约7.77℃,燃尽时间缩短了9.03 s,半焦燃烧的NO和CO生成量大幅下降(NO 68%,CO 39%)。5%Fe_(2)O_(3)-5%MnO_(2)复合添加剂对半焦燃烧和脱硝具有一定的协同作用,其催化效果优于单一添加剂。探讨了复合添加剂催化半焦燃烧和脱硝的反应机理。

To investigate the effect of Fe_(2)O_(3) and MnO_(2) on the combustion process of semi-coke,the combustion characteristics of semi-coke at 100~900℃were measured by thermogravimetric analyzer(TGA).The structure parameters of semi-coke ash were determined by nitrogen adsorption method(BET/BJH),and the surface morphology was observed by scanning electron microscopy(SEM).The surface ion concentration was determined by X-ray photoelectron spectroscopy(XPS).The results showed that the ignition temperature of semi-coke was increased by 9.04℃and 13.55℃,the burnout time was significantly shortened by 22.62 s and 54.18 s with the addition of 5%Fe_(2)O_(3) and 5%MnO_(2),separately.Moreover,there was a decline in the total amounts of NO and CO emission(NO 49%,36%,CO 10%,18%).However,the ignition temperature of semi-coke was reduced about 7.77℃,the burnout time was significantly shortened about 9.03 s,the reduction of NO and CO(NO 68%,CO 39%)was significantly reduced with addition of 5%Fe_(2)O_(3)-5%MnO_(2).The 5%Fe_(2)O_(3)-5%MnO_(2) composite additives had a certain synergistic effect on semi-coke combustion,which was better than that of the single additive.Then,the reaction mechanism of the composite additives for the combustion and denitrification of semi-coke was discussed.