The invention discloses an external catalytic
cracking heater with pre-distributed particles and is suitable for a catalytic
cracking device in an
oil refinery. The external catalytic
cracking heater is characterized in that a plurality of
unit type heat exchange tubes (6) with independent water inlets and water outlets are arranged inside an external heater (4); the heat exchange tubes (6) extend from the top to the bottom of the external heater (4), and the bottom of the external heater is provided with a guide bracket (2) which limits transverse swing of the heat exchange tubes (6); the lower parts of the heat exchange tubes (6) are immersed in a dense-phase
fluidized bed (11) at the bottom of the external heater (4); hot catalyst particles entering from a catalyst inlet (10) in the middle of the external heater (4) enter an
annular fluidized bed (17), and the hot particles uniformly flow into the dense-phase
fluidized bed (11) from the upper edge of a side wall (15) on the inner side of the
annular fluidized bed (17) or an overflow notch (19) formed in the side wall (15) on the inner side by utilizing the particle pre-
distribution function of the
annular fluidized bed (17); the hot particles are contacted and cooled with the side wall of the heat exchange tubes (6) and flow out of a catalyst outlet (1) at the bottom of the external heater (4) in the dense-phase
fluidized bed (11); and fluidized gas in the dense-phase fluidized
bed (11) is introduced from a bottom gas
distributor (2), and the fluidized gas which passes through the dense-phase fluidized
bed (11) and the fluidized gas in the annular fluidized
bed (17) are mixed to enter a dilute
phase space of a catalytic cracking device regenerator through a gas outlet (7) formed on the top of the external heater (4).