Recycling fluidization system

A system for recycling a powdery solid material used as a catalyst or a heat medium which comprises in combination:

• a downflow moving bed forming element having an upper part to which said solid material is supplied;
• a first dense phase fluidized bed forming element connected with a lower portion of said downflow moving bed forming element;
• a second dense-phase fluidized bed forming element having an inlet to which said solid material is introduced through a feed rate adjusting element in an upper half portion of the second dense-phase fluidized bed forming element where a pressure distribution is low and an upflow moving bed forming element having a lower end connected with and extending longitudinally from an upper end of said second dense-phase fluidized bed forming element, and a second feed rate adjusting element in communication with the upflow moving bed forming element through which said solid material is supplied into said downflow moving bed forming element, wherein the system is capable of maintaining a density of said solid material in said first dense-phase fluidized bed forming element of only 0.4-0.8 g/cm3 higher than that in said upflow fluidized bed forming element to recycle said solids.