Low carbon footprint integrated process for recycle content olefin producers
Integrated processes and facilities for providing recycled content hydrocarbon products (r-products) from mixed waste plastic are provided. Carbon dioxide capture and energy recovery from one or more process streams described herein increase energy efficiency and help reduce overall environmental impact while producing valuable final products from chemically recycled waste plastic.
1 . A process for making a recycled content hydrocarbon product (r-product), the process comprising:
(a) liquefying a plastic in a liquification zone to provide a liquified waste plastic;
(b) pyrolyzing at least a portion of the liquified waste plastic in a pyrolysis furnace of a pyrolysis facility to produce a recycled content pyrolysis vapor (r-pyrolysis vapor);
(c) introducing at least a portion of the r-pyrolysis vapor into a separation zone downstream of a cracker furnace in a cracking facility; and
(d) separating at least a portion of the r-pyrolysis vapor in the separation zone to provide the recycled content hydrocarbon product,
wherein at least one of following steps (i) through (iii) is also performed—
(i) passing at least a portion of a flue gas from the pyrolysis furnace and/or the cracker furnace through a carbon dioxide removal zone to recover at least a portion of the carbon dioxide;
(ii) recovering thermal energy from a flue gas from the pyrolysis furnace and/or the cracker furnace and transferring at least a portion of said thermal energy to said liquification zone; and
(iii) recovering an off-gas stream from the separation zone in the cracking facility and combusting at least a portion of the off-gas stream as fuel in the pyrolysis and/or cracker furnace.
2 . The process of claim 1 , wherein the process further comprises step (i) passing at least a portion of a flue gas from the pyrolysis furnace and/or the cracker furnace through a carbon dioxide removal zone to capture at least a portion of the carbon dioxide.
3 . The process of claim 2 , wherein the carbon dioxide removal zone recovers at least 75 percent of the CO2 introduced into the carbon dioxide removal zone in the flue gas and wherein a stream of CO2-depleted off gas is withdrawn from the carbon dioxide removal zone and comprises not more than 5 mole percent CO2.
4 . The process of claim 2 , further comprising compressing at least a portion of the flue gas from the pyrolysis furnace and/or the cracker furnace and introducing the compressed flue gas into the carbon dioxide removal zone.
5 . The process of claim 2 , wherein the carbon dioxide removal zone comprises an absorber/stripper system including a liquid absorbent for removing carbon dioxide from the flue gas, wherein the liquid absorbent comprises at least one liquid selected from the group of diethanolamine, monoethanolamine, methyldiethanolamine, diisopropanolamine, diglycolamine, piperazine, sodium hydroxide, sodium carbonate, sodium bicarbonate, potassium hydroxide, potassium carbonate, potassium bicarbonate, SELEXOL®, methanol, glycol ether, and combinations thereof.
6 . The process of claim 2 , wherein the carbon dioxide removal zone comprises a solid CO2 absorbent, wherein the solid CO2 absorbent comprises a solid selected from the group consisting of metal oxides, metal hydroxides, molecular sieve, zeolite, activated carbon, and combinations thereof.
7 . The process of claim 1 , wherein the process further comprises step (ii) recovering energy from a flue gas from the pyrolysis furnace and/or from a flue gas from the cracker furnace and using at least a portion of the recovered energy to perform the liquefying of step (a).
8 . The process of claim 7 , wherein the recovering of step (ii) includes warming a heat transfer medium via indirect heat exchange with the flue gas and using the warmed heat transfer medium to warm at least one process stream associated with the liquefying of step (a).
9 . The process of claim 1 , wherein the process further comprises step (iii) recovering an off-gas stream from the cracking facility and using at least a portion of the off-gas stream as fuel in the pyrolysis and/or cracker furnace.
10 . The process of claim 9 , wherein the off-gas stream originates from the separation zone of the cracking facility, wherein the off-gas stream comprises at least 50 mole percent hydrogen and/or at least 50 mole percent methane.
11 . The process of claim 1 , prior to the liquefying of step (a), separating a stream of mixed plastic waste (MPW) into a polyolefin-enriched (PO-enriched) plastic and a polyethylene terephthalate-enriched (PET) enriched plastic in a MPW separator.
12 . The process of claim 11 , wherein the MPW separator is co-located with the pyrolysis facility.
13 . The process of claim 11 , further comprising, subjecting at least a portion of the PET-enriched plastic to solvolysis in a solvolysis facility to produce recycled content dimethyl terephthalate (r-DMT).
14 . The process of claim 13 , wherein the solvolysis produces one or more co-products, and further comprising introducing at least a portion of the co-products into the liquification zone, and wherein the solvolysis facility is co-located with at least one of the pyrolysis facility and the cracking facility.
15 . The process of claim 11 , wherein the plastic liquefied in step (a) comprises the PO-enriched plastic from the MPW separator.
16 . The process of claim 1 , further comprising separating at least a portion of the r-pyrolysis vapor into a recycled content pyrolysis gas (r-pygas) and a recycled content pyrolysis oil (r-pyoil), wherein at least a portion of the r-pygas is introduced into the separation zone downstream of the cracker furnace.
17 . The process of claim 16 , wherein the r-pyrolysis vapor includes at least 10 weight percent of r-pygas.
18 . The process of claim 16 , further comprising cracking at least a portion of the r-pyoil in a fluidized catalytic cracker (FCC) to provide a recycled content cracked gas (r-cracked gas) and, optionally, separating at least a portion of the r-cracked gas in the separation zone of the cracking facility.
19 . The process of claim 1 , wherein the pyrolysis facility and the cracking facility are co-located.
20 . The process of claim 18 , wherein at least one of the pyrolysis facility and the cracking facility are a commercial-scale facility.