Abstract: According to one or more embodiments of the present disclosure, a riser may be operated by a method including repeatedly heating and cooling a riser between an operational temperature and a non-operational temperature. When the riser is heated from a non-operational temperature to an operational temperature, the riser undergoes thermal expansion. When the riser is cooled from an operational temperature to a non-operational temperature, the riser undergoes thermal contraction. The riser undergoes irreversible growth over repeated heating and cooling cycles, and the length of a lower section of an upper riser portion is sized to accommodate the irreversible growth from cycled thermal expansion of the riser.

Abstract: According to one or more embodiments, olefins may be produced by contacting a hydrocarbon feed stream with a particulate solid in a reaction vessel. The reaction vessel may be connected to a riser. The riser may extend through a riser port of an outer shell of a particulate solid separation section such that the riser may comprise an interior riser segment and an exterior riser segment. The particulate solid separation section may include a gas outlet port, a riser port, and a particulate solid outlet port. The particulate solid separation section may house a gas/solids separation device and a solid particulate collection area. The riser port may be 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. The particulate solid may be separated from an olefin-containing product stream in the gas/solids separation device.

Abstract: According to one or more embodiments, particulate solids may be regenerated in a particulate solid treatment vessel. The particulate solid treatment vessel may be connected to a riser. The riser may extend through a riser port of an outer shell of a particulate solid separation section such that the riser may comprise an interior riser segment and an exterior riser segment. The particulate solid separation section may include a gas outlet port, a riser port, and a particulate solid collection area. The riser port may be 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. The particulate solids may be separated from gasses in the particulate solid separation section.

Abstract: A supported riser apparatus may be housed at least partially within a vessel. The supported riser apparatus may include a riser including a non-vertical riser segment, a non-linear riser segment, and a vertical riser segment. The supported riser apparatus may further include a support member comprising a proximal end and a distal end. The proximal end of the support member may be connected to the non-vertical riser segment and the angle between the support member and the non-vertical riser segment may be from 15 to 75. The supported riser apparatus may include a support structure connected to the riser and the support member and an expansion guide connected to an interior surface of the vessel. The expansion guide may be shaped and positioned such that the support member slides across the expansion guide as the support member undergoes thermal expansion or thermal contraction.

Abstract: According to one or more embodiments of the present disclosure, a riser may include a lower riser portion, where the lower riser portion terminates at an upper end of the vertical riser segment, and an upper riser portion including a lower end, where the lower end of the upper riser portion may be positioned around the upper end of the vertical riser segment of the lower riser portion. The riser may also include a first guide and a second guide each positioned on opposite sides of the interior of the lower end of the upper riser portion. The vertical riser segment of the lower riser portion may be guided in a direction substantially parallel with the outer surface of the first guide and the outer surface of the second guide when the lower riser portion expands or contracts due to changes in temperature.

Abstract: A method for mitigating the condensation of liquid hydrocarbons and subsequent coke deposition in refinery reactor units by dew point suppression.