Fluidized bed heat exchanger

Abstract

A vertical tube heat exchanger for use with fluidized solid particulates as a heat transfer medium includes a plurality of vertically extending spaced apart tubes for containing an internal fluid flowing in heat transfer relationship with the walls of the tube. A containment housing is provided around the tubes for containing a flow of fluidized solid particulates moving through a heat exchange chamber in the housing around the exterior surface of the tubes. A gas plenum chamber is provided adjacent a lower end of the containment housing for directing fluidizing gas into the solid particulates. The housing includes a dividing floor between an upper heat exchange chamber and a lower plenum chamber and the floor is formed with openings in concentric alignment with the vertical tubes for injecting fluidizing gas into the heat exchange chamber around the tubes to flow upwardly into a bed of solid particulates. A bubble cap is provided around each tube for preventing the solid particulates from passing into the plenum chamber while at the same time permitting the injected fluidizing gas to flow upwardly into the heat exchange chamber. The bubble caps also accommodate relative expansion and contraction between the tubes and the floor of the housing to prevent a build up of stress between these components.