It is very important to measure both the concentration and size distribution of particles in flue gas by an on-line method. In particular, it is required to measure the particle size distribution of pulverized coal to control combustion conditions of pulverized coal and the performance of a coal pulverizer.
In this research, an on-line measuring apparatus of both particle size distribution and concentration has been developed. This apparatus consists of three-stage classifiers and load cells to weigh the classified particles. The particle size distribution is calculated from cut sizes of the classifiers and weight fractions of the classified particles. The overall particle concentration is decided from the total weight of the collected particles and the total volume of induced gas. The particle size distributions calculated from this method are in fairly good agreement with the one measured by a conventional light diffraction method.

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Composite particles constituted of fine AlN powder and polystyrene as the base polymer were prepared by suspension polymerization. To change the viscosity of the dispersed phase at the beginning of suspension polymerization, preliminary bulk polymerization of styrene containing AlN powder was carried out prior to suspension polymerization. Interfacial polycondensation was also carried out to form the polyamide film on the surface of the dispersed phase droplet. The AlN content of the composite particles increased with increase in the viscosity of the dispersed phase due to preliminary bulk polymerization and with decrease in the impeller speed during suspension polymerization. Formation of the polyamide film was found to effectively prevent AlN powder from escaping to the continuous phase, and this led to the increase in the AlN content. The dispersion state of AlN powder in the base polymer was found to be controlled by the preparation conditions.

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