Processes and systems for making recycle content hydrocarbons through a propylene fractionator
Processes and systems for making recycle content hydrocarbons, including olefins, from recycled waste material. Recycle waste material may be pyrolyzed to form recycle content pyrolysis oil composition (r-pyoil), at least a portion of which may then be cracked to form a recycle content olefin composition (r-olefin). The r-olefin may then be further separated into product streams in a separation zone downstream of the cracker furnace. The presence of recycle content hydrocarbons may facilitate more efficient operation of one or more distillation columns in the separation zone, including the propylene fractionator.
1. A process for making olefins, said process comprising:
(a) steam cracking a cracker feedstock comprising r-pyoil that has not been hydrotreated, said cracker feedstock comprising said r-pyoil in an amount of 1 to 25 wt % and non-recycle content propane in an amount of at least 60 wt %, each based on the weight of the cracker feedstock, in a cracker furnace to provide an olefin-containing effluent comprising r-propylene and propane; and
(b) separating at least a portion of said olefin-containing effluent in a propylene fractionator,
wherein a mole ratio of propylene to propane in the at least a portion of said olefin-containing effluent is at least 0.1% higher than if said olefin-containing effluent did not include said r-propylene but had the same mass flow rate to the column.
2. A process for making olefins, said process comprising:
(a) steam cracking a cracker feedstock comprising r-pyoil that has not been hydrotreated, said cracker feedstock comprising said r-pyoil in an amount of 1 to 25 wt % and non-recycle content propane in an amount of at least 60 wt %, each based on the weight of the cracker feedstock, in a cracker furnace to provide an olefin-containing effluent comprising r-propylene and propane; and
(b) separating at least a portion of said olefin-containing effluent in a propylene fractionator to produce an overhead enriched in propylene and a bottoms stream enriched in propane,
wherein the mass flow rate of propane in said overhead stream is at least 0.1% lower than if said olefin-containing effluent did not include said r-propylene but had the same mass flow rate to the column.
3. A process for making olefins, said process comprising:
(a) steam cracking a cracker feedstock comprising r-pyoil that has not been hydrotreated, said cracker feedstock comprising said r-pyoil in an amount of 1 to 25 wt % and non-recycle content propane in an amount of at least 60 wt %, each based on the weight of the cracker feedstock, in a cracker furnace to provide an olefin-containing effluent comprising r-propylene and propane; and
(b) separating at least a portion of said olefin-containing effluent in a propylene fractionator,
wherein the amount of propylene in the at least a portion of said olefin-containing effluent is at least 0.1% higher than if said cracker feedstock did not include said r-pyoil, all other conditions being the same.