Using special parameter back-calculation techniques to extract size distribution information of pneumatically conveyed particles

Many industrial processes involve the measurement and control of particle size distribution. On a fossil fuel power station specifically, the measurement of the particle size distribution of the finely milled coal used to fuel the power station, is becoming increasingly important. An investigation revealed a cost-effective technique to achieve this goal. The method is based on the principle that particles colliding with a structure cause that structure to start vibrating at its natural or resonant frequencies. Different sized particles cause different resonant frequencies of the structure to be exited or evoked. Thus, a variation in particle size distribution will cause a variation in the amplitudes of the different resonant vibration peaks of the structure. By analyzing these peaks, variations in the particles size distribution can be monitored. Extraction of the absolute particle size information from the complex vibration signals was accomplished using special parameter back-calculation techniques.