Minimum fluidization velocity of particles with different size distributions at elevated pressures and temperatures

This paper presents a detailed investigation into the effect of pressure, temperature and particle size distribution (PSD) on the minimum fluidization velocity (U_mf). A series of measurement of U_mf were carried out under the pressure from 0.1 MPa to 0.5 MPa and the temperature from 300 °C to 850 °C on a lab-scale pressurized fluidized bed reactor for three narrow PSD and three wide PSD (binary, uniform, and Gaussian-type) silica sand particles. The results showed that the U_mf for narrow and wide PSDs both decreased with increasing temperature and decreased slightly with rising pressure. Besides, the Gaussian-type mixtures had almost the same U_mf as the reference narrow PSD particle, while the U_mf of binary and uniform PSD mixtures was larger than these two. Based on the experimental data, a new simple relationship for predicting U_mf of the different PSD particles at elevated pressures and temperatures was developed.