煤燃烧亚微米颗粒数浓度特性实验研究和理论分析

EXPERIMENTS OF NUMBER CONCENTRATIONS OF SUBMICRON PARTICULATE MATTERS DURING PULVERIZED COAL COMBUSTION AND THEORETICAL ANALYSIS

煤粉燃烧过程中亚微米颗粒数浓度的准确采样和测量是一个颇具挑战性的问题,本文基于清华大学高温一维炉实验系统产生的亚微米颗粒物,发展了适用于气溶胶扫描电迁移率颗粒粒径谱仪(SMPS)的两级氮气稀释水冷等速取样技术。为得到炉膛内亚微米颗粒的真实数浓度粒径分布,本文探索了不同稀释比对测量结果的影响,最后发展了基于成核、团聚和表面生长的颗粒群平衡模型来对两级稀释采样系统进行理论分析。

The accurate measurement of the distribution of number concentration of submicron particulate matters from high temperature sources is still challenging. Focusing on the submicron particulate matters from a quasi one-dimensional down-fired pulverized coal eombustor located at Tsinghua University, a two-stage nitrogen-aspirated, water-cooling isokinetic sampling and dilution system was modified to meet the Scanning Mobility Particle Sizer （SMPS） for the number concentration measurement. The effect of the dilution ratio on the measured number concentrations of PM1 is investigated. Finally, a population balance model considering particle nucleation, coagulation and surface growth was developed. Both the experiments and model predictions produce a solid basis for the future modification of the dilution and sampling system as well as the accurate measurement of number concentration of PM1.