Processes and systems for co-processing a hydrocarbon feed and a heavy feed containing a plastic material
Processes and systems for hydrocarbon pyrolysis. In some embodiments, a hydrocarbon can be heated within a convection section of a steam cracking furnace and combined with an aqueous fluid to produce a heated mixture. A heavy feed that includes a plastic material can be introduced into a vessel and a portion of the plastic material can be cracked therein. Liquid and vapor effluents exiting the vessel can be obtained. At least a portion of the liquid effluent can be heated to produce a heated fluid stream that can be recycled to the vessel. The vapor effluent can be combined with the heated mixture to produce a combined mixture that can be heated within the convection section to produce a heated combined mixture. At least a portion of the heated combined mixture can be cracked within a radiant section of the steam cracking furnace to produce a steam cracker effluent.
1 . A process for converting hydrocarbons by pyrolysis, comprising:
heating a hydrocarbon feed within a convection section of a steam cracking furnace and combining the hydrocarbon feed with an aqueous fluid to produce a heated mixture comprising hydrocarbons and steam, wherein the heating is carried out before, during, and/or after the hydrocarbon feed is combined with the aqueous fluid, and wherein the heated mixture is a two-phase gas/liquid mixture;
introducing the heated mixture and a heavy feed comprising a plastic material into a vessel;
cracking a portion of the plastic material within the vessel under plastic pyrolysis conditions;
obtaining a liquid phase effluent and a vapor phase effluent exiting the vessel;
heating at least a portion of the liquid phase effluent to produce a heated fluid stream;
recycling at least a portion of the heated fluid stream to the vessel;
heating the vapor phase effluent within the convection section of the steam cracking furnace to produce a heated vapor phase effluent; and
steam cracking the heated vapor phase effluent within a radiant section of the steam cracking furnace to produce a steam cracker effluent comprising olefins.
2 . The process of claim 1 , wherein the liquid phase effluent is heated in an internal heat exchanger disposed within the convection section of the steam cracking furnace.
3 . The process of claim 1 , wherein the liquid phase effluent is heated within an external heat exchanger outside of the steam cracking furnace.
4 . The process of claim 3 , wherein the liquid phase effluent is heated within the external heat exchanger by transferring heat from a heated hydrocarbon, a heated aqueous fluid, or a combination thereof, or by transferring heat from one or more electrical heating elements, or a combination thereof, and wherein, if present, the heated hydrocarbon comprises the stream cracker effluent, a cooled steam cracker effluent, a refinery hydrocarbon-containing stream, or a combination thereof.
5 . The process of claim 1 , further comprising removing a portion of the liquid phase effluent from the process.
6 . The process of claim 1 , wherein the heavy feed further comprises a carrier liquid mixed with the plastic material.
7 . The process of claim 1 , further comprising mixing a carrier liquid with at least a portion of the liquid phase effluent to produce a combined liquid phase mixture, wherein the combined liquid phase mixture is heated to produce the heated fluid stream.
8 . The process of claim 1 , wherein the liquid phase effluent comprises a char, and the process further comprises:
introducing at least a portion of the liquid phase effluent into a separation vessel; and
separating at least a portion of the char from the at least a portion of the liquid phase effluent to produce a char-lean liquid phase effluent, wherein at least a portion of the char-lean liquid phase effluent is heated to produce the heated fluid stream.
9 . The process of claim 8 , wherein the heavy feed further comprises a carrier liquid mixed with the plastic material.
10 . The process of claim 8 , further comprising mixing a carrier liquid with at least a portion of the char-lean liquid phase effluent to produce a combined liquid phase mixture, wherein the combined liquid phase mixture is heated to produce the heated fluid stream.
11 . The process of claim 6 , wherein the carrier liquid comprises a heat-soaked and/or hydrotreated hydrocarbon stream having an initial boiling point of at least 300° C.
12 . The process of claim 1 , wherein the plastic material comprises a contaminant-containing polymer and/or the heavy feed further comprises a compound comprising contaminant, and wherein the vapor phase effluent further comprises one or more contaminant-containing compounds, the process further comprising:
contacting the vapor phase effluent with a guard bed to remove at least a portion of the one or more contaminant-containing compounds to produce a contaminant-lean vapor phase stream, wherein the contaminant-lean vapor phase stream is combined with the heated mixture to produce the combined mixture.
13 . The process of claim 12 , wherein the plastic material comprises the contaminant-containing polymer, and wherein the contaminant-containing polymer comprises polyvinyl chloride, polyvinylidene chloride, chlorinated polyvinyl chloride, or a mixture thereof.
14 . The process of claim 1 , wherein the plastic pyrolysis conditions in the vessel comprises a temperature in a range from 300° C. to 550° C.
15 . The process of claim 1 , wherein the plastic material comprises a nitrogen-containing polymer, a chlorine-containing polymer, an oxygen-containing polymer, a polyethylene polymer, a polypropylene polymer, a polystyrene polymer, a polyamide polymer, polyethylene terephthalate, ethylene vinyl acetate, a butadiene polymer, an isoprene polymer, an isobutylene polymer, or a mixture thereof.
16 . The process of claim 1 , wherein the hydrocarbon feed comprises crude oil or a fraction thereof.