A method for regenerating a particulate solid, the method comprising: regenerating the particulate solid in a particulate solid treatment vessel, where the regenerating of the particulate solid comprises one or more of: oxidizing the particulate solid by contact with an oxygen-containing gas; combusting coke present on the particulate solid; or combusting a supplemental fuel to heat the particulate solid; passing the particulate solid through a riser, the riser extending through a riser port of an outer shell of a particulate solid separation section such that the riser comprises an interior riser segment positioned in an interior region of the particulate solid separation section and an exterior riser segment positioned outside of the outer shell of the particulate solid separation section, wherein the particulate solid separation section comprises at least the outer shell defining the interior region of the particulate solid separation section, the outer shell comprising a gas outlet port, the riser port, and a particulate solid outlet port, and wherein the outer shell houses a gas/solids separation device and a particulate solid collection area in the interior region of the particulate solid separation section, and wherein the riser port is positioned on a sidewall of the outer shell such that it is not located on a central vertical axis of the particulate solid separation section; separating the particulate solid from gasses in the gas/solids separation device; and passing the particulate solid, separated from the gasses, to the particulate solid collection area located proximate the central vertical axis of the particulate solid separation section. regenerating the particulate solid in a particulate solid treatment vessel, where the regenerating of the particulate solid comprises one or more of: oxidizing the particulate solid by contact with an oxygen-containing gas; combusting coke present on the particulate solid; or combusting a supplemental fuel to heat the particulate solid; oxidizing the particulate solid by contact with an oxygen-containing gas; combusting coke present on the particulate solid; or combusting a supplemental fuel to heat the particulate solid; passing the particulate solid through a riser, the riser extending through a riser port of an outer shell of a particulate solid separation section such that the riser comprises an interior riser segment positioned in an interior region of the particulate solid separation section and an exterior riser segment positioned outside of the outer shell of the particulate solid separation section, wherein the particulate solid separation section comprises at least the outer shell defining the interior region of the particulate solid separation section, the outer shell comprising a gas outlet port, the riser port, and a particulate solid outlet port, and wherein the outer shell houses a gas/solids separation device and a particulate solid collection area in the interior region of the particulate solid separation section, and wherein the riser port is positioned on a sidewall of the outer shell such that it is not located on a central vertical axis of the particulate solid separation section; separating the particulate solid from gasses in the gas/solids separation device; and passing the particulate solid, separated from the gasses, to the particulate solid collection area located proximate the central vertical axis of the particulate solid separation section. <EOS>