Processes and systems for removing coke particles from a pyrolysis effluent

Patent metadata

Field	Value
Publication number	US-12473497-B2
Application number	US-202118267476-A
Country	US
Kind code	B2
Filing date	Dec 30, 2021
Priority date	Jan 8, 2021
Publication date	Nov 18, 2025
Grant date	Nov 18, 2025

Abstract

Processes and systems for pyrolysing a hydrocarbon. In some examples, the process can include mixing a cooled hydrocarbon effluent and a cooled de-coking effluent to produce a combined effluent. The combined effluent can be introduced into an inlet conduit of a separator under conditions that provide >80 wt. % of the plurality of coke particles with a Stokes number of >10. From a first exit conduit of the separator >55 wt. % of the plurality of coke particles in the combined effluent can be removed, and from a second exit conduit of the separator a coke-lean hydrocarbon effluent that includes <45 wt. % of the plurality of coke particles in the combined effluent can be removed. The first exit conduit and the second exit conduit can be coupled to the inlet conduit.

First claim

What is claimed is:

1 . A hydrocarbon pyrolysis process, comprising:
introducing a hydrocarbon feed into a pyrolysis furnace comprising a first radiant coil and a second radiant coil; pyrolysing at least a portion of a first quantity of the hydrocarbon feed in the first radiant coil to produce a first hydrocarbon effluent and to deposit coke on an inner surface of the first radiant coil; pyrolysing at least a portion of a second quantity of the hydrocarbon feed in the second radiant coil to produce a second hydrocarbon effluent and to deposit coke on an inner surface of the second radiant coil; decreasing a flow rate of the hydrocarbon feed into the first radiant coil while maintaining a flow rate of the hydrocarbon feed into the second radiant coil; introducing a decoking feed comprising steam or a mixture of steam and air into the first radiant coil of the pyrolysis furnace to remove at least a portion of the coke deposited on the inner surface of the first radiant coil and to produce a de-coking effluent comprising steam and a plurality of coke particles; indirectly exchanging heat from the second hydrocarbon effluent to water, steam, or a mixture thereof to produce a cooled second hydrocarbon effluent; indirectly exchanging heat from the de-coking effluent to water, steam, or a mixture thereof to produce a cooled de-coking effluent; mixing the cooled second hydrocarbon effluent and the cooled de-coking effluent to produce a combined effluent; introducing the combined effluent into an inlet conduit of a separator under conditions that provide ≥80 wt. % of the plurality of coke particles with a Stokes number of ≥10; removing ≥55 wt. % of the plurality of coke particles in the combined effluent from a first exit conduit of the separator, and removing a coke-lean hydrocarbon effluent comprising ≤45 wt. % of the plurality of coke particles in the combined effluent from a second exit conduit of the separator, wherein the first exit conduit is coupled to the inlet conduit, and wherein the second exit conduit is coupled to the inlet conduit, wherein: the plurality of coke particles is introduced into a coke catch apparatus, a flow control device couples the first exit conduit to the coke catch apparatus, and a total length of the first exit conduit and the flow control device is ≤8 times an inner diameter of the first exit conduit.

2 . The process of claim 1 , further comprising introducing steam is introduced into the coke catch apparatus adjacent the location the flow control device couples the first exit conduit to the coke catch apparatus.

3 . The process of claim 1 , wherein the combined effluent is introduced into the inlet conduit of the separator under conditions that provide ≥80 wt. % of the plurality of coke particles with a Stokes number of ≥10 to about 15,000, and wherein ≥70 wt. % of the plurality of coke particles in the combined effluent is recovered from the first exit conduit.

4 . The process of claim 1 , wherein a longitudinal axis of the first exit conduit is substantially aligned with a longitudinal axis of the inlet conduit, and wherein the second exit conduit is angled with respect to the inlet conduit and the first exit conduit to provide an angle of about 20° to about 90° between a longitudinal axis of the second exit conduit and the longitudinal axis of the inlet conduit and an angle of about 90° to about 160° between the longitudinal axis of the second exit conduit and the longitudinal axis of the first exit conduit.

5 . The process of claim 1 , wherein a longitudinal axis of the first exit conduit is substantially aligned with a longitudinal axis of the inlet conduit, and wherein the second exit conduit is angled with respect to the inlet conduit and the first exit conduit to provide an angle of about 45° to about 90° between a longitudinal axis of the second exit conduit and the longitudinal axis of the inlet conduit and an angle of about 90° to about 135° between the longitudinal axis of the second exit conduit and the longitudinal axis of the first exit conduit.

6 . The process of claim 1 , wherein the hydrocarbon feed comprises ethane, propane, naphtha, gas oil, vacuum gas oil, waxy residues, atmospheric residues, residue admixtures, crude oil, or a mixture thereof.

7 . The process of claim 1 , wherein the decoking feed comprises a mixture of steam and air.

8 . The process of claim 1 , wherein a flow path from the inlet conduit into the first exit conduit is free of any obstruction, and wherein a flow path from the inlet conduit into the second exit conduit is free of any obstruction.

9 . The process of claim 1 , wherein a longitudinal axis of the first exit conduit is oriented at an angle of about 0° to about 90° with respect to a surface of the earth.

10 . The process of claim 1 , further comprising indirectly exchanging heat from the combined effluent to water, steam, or a mixture of water and steam to produce a cooled combined effluent, wherein the cooled combined effluent is introduced into the inlet conduit.

11 . A hydrocarbon pyrolysis process, comprising:
introducing a hydrocarbon feed into a pyrolysis furnace comprising a first radiant coil and a second radiant coil, wherein the hydrocarbon feed comprises ethane, propane, naphtha, gas oil, vacuum gas oil, waxy residues, atmospheric residues, residue admixtures, crude oil, or a mixture thereof; pyrolysing at least a portion of a first quantity of the hydrocarbon feed in the first radiant coil to produce a first hydrocarbon effluent and to deposit coke on an inner surface of the first radiant coil; pyrolysing at least a portion of a second quantity of the hydrocarbon feed in the second radiant coil to produce a second hydrocarbon effluent and to deposit coke on an inner surface of the second radiant coil; decreasing a flow rate of the hydrocarbon feed into the first radiant coil while maintaining a flow rate of the hydrocarbon feed into the second radiant coil; introducing a decoking feed comprising steam or a mixture of steam and air into the first radiant coil of the pyrolysis furnace to remove at least a portion of the coke deposited on the inner surface of the first radiant coil and to produce a de-coking effluent comprising steam and a plurality of coke particles; indirectly exchanging heat from the second hydrocarbon effluent to water, steam, or a mixture thereof to produce a cooled second hydrocarbon effluent; indirectly exchanging heat from the de-coking effluent to water, steam, or a mixture thereof to produce a cooled de-coking effluent; mixing the cooled second hydrocarbon effluent and the cooled de-coking effluent to produce a combined effluent; introducing the combined effluent into an inlet conduit of a separator under conditions that provide ≥80 wt. % of the plurality of coke particles with a Stokes number of ≥10 to about 20,000; removing ≥70 wt. % of the plurality of coke particles in the combined effluent from a first exit conduit of the separator, and removing a coke-lean hydrocarbon effluent comprising ≤30 wt. % of the plurality of coke particles in the combined effluent from a second exit conduit of the separator, wherein:
the first exit conduit is coupled to the inlet conduit,
the second exit conduit is coupled to the inlet conduit,
a longitudinal axis of the first exit conduit is substantially aligned with a longitudinal axis of the inlet conduit,
the second exit conduit is angled with respect to the inlet conduit and the first exit conduit to provide an angle of about 45° to about 90° between a longitudinal axis of the second exit conduit and the longitudinal axis of the inlet conduit and an angle of about 90° to about 135° between the longitudin

Assignees

• Exxonmobil Chemical Patents Inc
• Exxonmobil Engineering And Tech Company

Inventors

• Hirst Thomas T
• Stephens George
• Spicer David

Classifications

• B01D45/06

  by reversal of direction of flow · CPC title

• C10G2300/1081

  Alkanes · CPC title

• C10G2300/1074

  Vacuum distillates · CPC title

• C10G2300/107

  Atmospheric residues having a boiling point of at least about 538 °C · CPC title

• B07B7/00

  Selective separation of solid materials carried by, or dispersed in, gas currents (sieves or filters for separating dispersed particles from gases or vapours B01D) · CPC title