New ways of fluidization in a centrifugal field

Abstract

Both numerical and experimental observations on two novel technologies for fluidization in a centrifugal field are presented. In the rotating fluidized bed in a static geometry, the rotating motion of the particle bed is generated by the tangential injection of the fluidization gas in the fluidization chamber via multiple gas inlet slots, so i.e. by the tangential fluidization of the particle bed. The fluidization gas is forced to leave the fluidization chamber via a centrally positioned chimney results in a combined tangential-radial motion of the fluidization gas through the particle bed. In case the radial gas-solid drag force balances the centrifugal force, radial fluidization of the particle bed can be obtained. As a result of the tangential fluidization of the particle bed in rotating fluidized beds in a static geometry, radial fluidization of the particle bed is, however, not necessary to take full advantage of the improved particle bed uniformity and the higher gas-solid slip velocities at which fluidized beds can be operated in a centrifugal field. The rotating chimney can be combined with any rotating fluidized bed technology and allows increasing locally, i.e. in the vicinity of the chimney, the centrifugal force. The rotating chimney consists of multiple blades and rotates in the same sense than the rotating particle bed, but at higher rotational speeds. The fluidization gas is forced through the chimney blades to the chimney outlet. As a result of the centrifugal force generated by the rotating chimney, particles are not entrained by the fluidization gas, but remain rotating around the chimney in a fluidized state. © 2008 WIT Press.