Heat exchanger with backmix and flow-through particle cooling

摘要

A method and apparatus for cooling hot FCC catalyst particles in a heat exchange zone that is separate and distinct from the regenerator having an upper portion that operates in a flow-through mode and a lower part that operates in a back mix mode. Catalyst 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 catalyst with a cooling fluid. Catalyst 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. Catalyst 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 section of the heat exchange zone 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 section of the exchanger.