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US 10,294,432 B2Granted
Steam cracker product fractionation
AssigneeExxonMobil Chemical Patents Inc.
InventorsAlok Srivastava, David C. Dutschmann, Thomas W. Pavia
Life of this patent
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Abstract
The invention generally relates to processes for separating steam cracker products by fractional distillation, and to systems and apparatus useful in such processes. More specifically, the invention relates to decreasing the amount of fractionator fouling that can result from increasing the amount of hydrocarbon molecules in the steam cracker feed having four or fewer carbon atoms.
Claims20
A process for steam cracking hydrocarbon, the process comprising:
- (a) combining a hydrocarbon feed with steam to produce a steam cracker feed;
- (b) exposing the steam cracker feed to a temperature ≥400° C. under steam cracking conditions to produce a steam cracker effluent that is at least partially in the vapor phase;
- (c) cooling the steam cracker effluent to condense a portion of the vapor phase into a liquid phase;
- (d) separating in at least one fractionator at least a portion of the steam cracker effluent's vapor phase from the liquid phase, the separated vapor phase comprising molecular hydrogen, methane, and C2+ hydrocarbon;
- (e) cooling the separated vapor phase to condense a steam cracker naphtha comprising diolefin and C5+ hydrocarbon;
- (f) dividing the condensed steam cracker naphtha into first and second steam cracker naphtha streams, and introducing into the at least one fractionator a first reflux stream comprising at least a portion of the first steam cracker naphtha stream;
- (g) hydroprocessing at least a portion of the second steam cracker naphtha stream under hydroprocessing conditions effective for dimerization of at least a portion of the second steam cracker naphtha stream's hydrocarbon and hydrogenation of at least a portion of the second steam cracker naphtha stream's diolefin to produce a hydroprocessed steam cracker naphtha;
- and
- (h) introducing to the at least one fractionator a second reflux stream comprising at least a portion of the hydroprocessed steam cracker naphtha,
- wherein the at least one fractionator comprises a primary fractionator having a stripping region, a rectification region, and a quenching region, the rectification region being located between the stripping region and the quenching region.
7 more elements
A method for lessening steam cracker fractionator fouling, the method comprising:
- during a first time interval,
- (a) combining a hydrocarbon feed with steam to produce a steam cracker feed, the hydrocarbon feed comprising C5+ hydrocarbon;
- (b) introducing the steam cracker feed into a radiant section of at least one steam cracking furnace and exposing the steam cracker feed in the steam cracking furnace to a temperature ≥400° C. under steam cracking conditions to produce a steam cracker effluent that is at least partially in the vapor phase;
- (c) cooling the steam cracker effluent to condense a portion of the vapor phase into a liquid phase;
- (d) separating in at least one fractionator at least a portion of the steam cracker effluent's vapor phase from the liquid phase, the separated vapor phase comprising molecular hydrogen, methane, and C2+ hydrocarbon;
- (e) cooling the separated vapor phase to condense a steam cracker naphtha comprising diolefin and C5+ hydrocarbon;
- (f) dividing the condensed steam cracker naphtha into first and second steam cracker naphtha streams, and introducing into the at least one fractionator a flow of a first reflux stream comprising at least a portion of the first steam cracker naphtha stream;
- (g) hydroprocessing at least a portion of the second steam cracker naphtha stream under hydroprocessing conditions effective for dimerization of at least a portion of the second steam cracker naphtha stream's hydrocarbon and hydrogenation of at least a portion of the second steam cracker naphtha stream's diolefin to produce a hydroprocessed steam cracker naphtha;
- and
- during a second time interval,
- (h) adding one or more of ethane, propane, and butanes to the hydrocarbon feed;
- and
- (i) introducing to the at least one fractionator a flow of a second reflux stream comprising at least a portion of the hydroprocessed steam cracker naphtha in order to lessen foulant accumulation in the fractionator,
- wherein the at least one fractionator comprises a primary fractionator having a stripping region, a rectification region, and a quenching region, the rectification region being located between the stripping region and the quenching region.
11 more elements
Dependencies are inferred from the claim text.