Study On Flow Characteristics Of The Pressurized Oxygen-enriched Fluidized Bed

An experimental study of the influence of pressure on Umf was carried out in a bubbling fluidized bed in the range of operating absolute pressure 0.1MPa~0.6MPa and temperiture 100℃~800℃with quartz and ceramic sand. The results show that: Umf for Geldart B powder and Geldart D powder is found to decrease, but the relative change of it decreases with the rising of pressure. Umf for tiny particles is found to decrease, but the relative change of it decreases with the rising of temperiture, and for large particles Umf is found to increase with the rising of temperiture. However, there is no influence of pressure on Umf for the Geldart A powder. The temperature has very big effect on the particle fluid dynamics characteristics. The flow characteristics under the high temperature and the room temperature are different. Therefore the particle flow characteristics under normal temperature are different with the rule under the environment of high temperature in design and operation of actual industrial fluidized bed device. Based on Ergun equation and bed stress analysis, a new equation between Remf and Ar is developed by least square fitting the experimental data. The discrete degree between predicted Remf and experimental results is in the range of 10%. It is useful for the design and operation of the pressured fluidized bed reactor. All the minimum fluidization velocity empirical formulas have their fitting range, and it will lead to greater error when beyond its experimental conditions. Therefore, the minimal fluidization velocity should be determined by experiment in the design fluidized bed condition to reduce design error.The air quantity of fan sending is found to increase with the rising of pressure. However, the influence of temperature is different with different particle size, which can be explained by different variation rules of density and minimum fluidization velocity with system pressure and temperature.