Research Of Hafnium Oxide In Cold-State Fluidization Experiment

Combined the zirconium tetrachloride fluidization method with the fixed bed of hafnium tetrachloride production process analyzing, the paper studies the fluidization characteristics of hafnium oxide. The density of hafnium oxide is1.67times higher than that of zirconium, there are a lot of difference in the fluidization characteristics. So it is necessary to conduct a more comprehensive study of fluidization characteristics of hafnium oxide.According to the whole stable bed theoretical description and experimental comparison we know. With the increasing of gas velocity, the fluidization condition from unstable to stable, it has a sharp rise in Distribution plate resistance. Due to the increase in porosity cause a decline in the material layer resistance coefficient, material layer pressure drop. After fluidization keep stable the porosity remain stable, the material layer pressure drop tends to smooth.Distribution plate drag is an important factor affecting the quality of fluidization, the distributor perforated rate, thickness, gas velocity have been simulated in this paper. We got the pressure contours, turbulence intensity contours, the distribution lines of the fluid flow. The calculation results show that the distributor pressure have an exponential rise with the gas velocity increase. In this article the distribution plate drag is divided into frictional resistance and local resistance. The numerical simulation results give us the formula of local resistance and the ratio of resistance along the way with the local resistance in different distributor rate and thickness.We study the effects of fluidized bed height for fluidization quality by numerical simulation. When the ratio of the bed height to the diameter of bed is small, the length of gas path through the material layer is short difficult to mix gas phase and solid phase. When the ratio of the bed height to the diameter of bed is big, the bubble diameter is large, the ratio of the bed height to the diameter of bed should be between0.7and1.2. Study the effect of the bubble and the bubble formation process in the mixing process by numerical simulation method, the solid phase became a materials cycling with the center of bubble. The particle on the top and down of bubble movement upward. Both sides of the bubble material particles movement downward, the closer the position of the bubble, the better mixed. According to bed height, gas velocity, pressure distribution plate research and bed pressure to design the device for fluidization of hafnium oxide particles. Experiments show that particle size (74-100)μm of HfO2belong to the class B materials for bubbling bed or turbulent bed; When gas velocity changes from small to large, less than5m3/h, HfO2particles were very unstable and produced locally fluidized channeling phenomenon bed; HfO2critical fluidized particle velocity is about (5-6)m3/h, more than8m3/h, the bed change into the stability bubbling bed, bed height is about17cm-17.5cm, flow rate is between6m3/h.