A regenerator for an FCC apparatus. The regenerator includes an internal riser inside of a outer shell. The internal riser includes a cone and a cone skirt. An annulus is formed between the internal riser and the outer shell. A sealing apparatus for keeping catalyst out of a portion of the annulus comprises a first sealing element and a second sealing element disposed above the first sealing element. An annular trough in the annulus below the primary seal is filled with material that has a heat transfer coefficient at least as high as air to allow heat to get to the inner surface of the outer shell.