Heat exchanger for cooling fluidized particles with backmix and flow through modes of operation

摘要

Fluidized hot particulate material is cooled in a heat exchanger zone having an upper portion that operates in a flow through mode and a lower part that operates in a back mix mode. Particulate material descends from a collection zone into an upper inlet of a heater exchanger. The exchanger contains a series of tubes for indirect heat exchange of the particulate material with a cooling fluid. Particulate material leaves the exchanger through an outlet located at a mid portion of the exchanger. The section of the exchanger between the inlet and outlet comprises the flow-through portion. Particulate material undergoes further heat exchange below the outlet of the exchanger in the backmix portion. Fluidizing gas that enters at the bottom of the exchanger provides the necessary turbulence for particle interchange in the backmix portion of the cooler as well as transport of the particulate material through the flow through portion of the exchanger. The method and exchanger design facilitates the addition of surface area to the exchanger and increases the heat removal duty in the backmix portion of the exchanger.