温度对OPC装置在线检测颗粒物的影响

以球形SiO2颗粒为研究对象搭建高温测试实验台，用光学粒子计数器(OPC)测定了25?800℃下的颗粒数及其累计分布，并进行扫描电镜(SEM)和X射线衍射(XRD)分析，研究了高温对颗粒物在线检测结果的影响。结果表明，随加热温度升高，SiO2颗粒的粒径先变小后增大再变小，但颗粒物形状未发生变化；XRD衍射峰强度整体变弱，2θ?25.5o处的衍射峰宽化并移动，晶胞体积先增大后变小。根据SiO2晶胞体积与晶体介电常数的关系可排除加热使颗粒物粒径变化，温度升高导致SiO2颗粒晶体内部结构变化、晶体折射率变化，使测量结果存在2?3个粒径通道的误差，影响测量精度。

Influence of temperature on on-line detection of particulate matter using OPC device

In high temperature particles on-line detection experiments, with the spherical SiO2 particles as the research object, a high-temperature test bed was set up for this research. By utilizing optical particle counter (OPC), the quantity and cumulative distribution of particles with different particle sizes were measured under the operating condition of 25?800℃. The spherical SiO2 dust particles were observed and analyzed by SEM and XRD. The results showed that the particle size of spherical SiO2 particles first decreased, then increased and decreased later with the increase of heating temperature, while the shape and size of the particles at the corresponding temperature did not change. The XRD patterns showed that the diffraction intensity of spherical SiO2 particles became smaller, and the diffraction peak was broadened and shifted approximately at 2θ=25.5o. The unit cell volume of spherical SiO2 particles increased first and then decreased. Thus, a conclusion can be drawn that the connection between SiO2 unit cell volume and crystal dielectric constant led to the change of the internal structure of SiO2 particles, as a result the refractive index of the particles crystal changed, thus resulting in a change in the refractive index, making the measurement results have 2~3 size error and the measurement accuracy was affected.