Air pressure drop across a particle moving bed in a three-dimensional cold model of a blast furnace

摘要

Particle moving beds are used for large-scale handling of bulk solids in various industries including gas-solids contact operations.Knowledge of the gas and solids velocity patterns is,therefore,important to improve the contact efficiency inside the bed.For this purpose,the particle velocity patterns were measured under aeration from below a three-dimensional cold model of a blast furnace by our Bore-Scope technique.The air velocity profile was estimated by combining both results of air pressure and particle velocity measurements on the basis of Ergun's equation and our previously developed mathematical model,respectively.As a result,the vertical particle velocity changes more rapidly in the radial and axial directions,increasing the solids feed rate at the same air flow rate and the air flow rate at the same feed rate.Then,the dead zone shrinks with increasing feed rate and expands with increasing air flow rate.The air velocity changes more with increasing feed rate at deeper beds in the radial direction.The air velocity increases in the core region where particles descend more slowly than in the annular region above the discharge outlet tubes,since more air could permeate through the core region (which has lower resistance to air flow) to keep the uniform pressure drop across the moving bed.