O_2/CO_2条件下燃煤颗粒物中As和Pb的分布规律研究

The Distribution Characteristics of As and Pb in Particulate Matters Under O_2/CO_2 Combustion of Coal

在高温沉降炉中进行了大同烟煤的燃烧实验,燃烧气氛为O2/N2=21:79、O2/CO2=21:79和O_2/CO2=29:71,采用旋风分离器和DGI(承重撞击器)系统分别收集燃烧产生的粗灰及颗粒物,并应用ICP-MS测量其中As和Pb两种元素的含量。实验结果表明,相较于O2/N2气氛,O2/CO2气氛会抑制颗粒物的生成,在O2/CO2燃烧气氛下,提高氧浓度将促进颗粒物的生成;O2/CO2气氛相较于O2/N2气氛,会提高颗粒物中As、Pb的浓度,特别是PM0.2-0.5;O2/CO2气氛下,提高氧气浓度将降低颗粒物中As、Pb的浓度,特别是PM0.2-0.5;所有燃烧工况下,As、Pb两种元素都大量富集于颗粒物之上,颗粒粒径越小,富集现象越明显,并在PM0.2-0.5处显著增强。

The combustion of Da Tong bituminous was conducted in a high-temperature drop tube furnace （DTF）, in which, the combustion atmospheres were O2/N2=21：79, O2/CO2=21：79 and O2/CO2=29：71. the combustion residues were collected by cyclone and DGI （Dekati Gravimetric Impacter） system, and the concentration of As, Pb in these collections was measured by ICP-MS. The experiment results indicate that： the particulate matters generated under O2/N2 are more than that under O2/CO2, and in O2/CO2, the higher oxygen concentration is, the more particulate matters generate. Compare to O2/N2, O2/CO2 improve the concentration of As and Pb in particulate matters, especially in PM0.2-0.5. Under O2/CO2, with the oxygen concentration increasing, the concentration of As and Pb in particulate matters decreases, especially in PM0.2-0.5. The enrichment of As and Pb in particulate matters is significant, and the finer the particle is, the more obvious the enrichment is, and a surge can be observed in PM0.2-0.5.