Process for heating the column for distillation of the C3 fraction from an FCC unit by means of a circuit of water heated by streams belonging to units placed upstream and/or downstream of the FCC unit

Patent metadata

Field	Value
Publication number	US-10473391-B2
Application number	US-201414902065-A
Country	US
Kind code	B2
Filing date	Jun 6, 2014
Priority date	Jul 1, 2013
Publication date	Nov 12, 2019
Grant date	Nov 12, 2019

Abstract

The present invention describes a process for heating the reboiler of the propane/propylene separation column situated downstream of an FCC unit and fed with the C3 cut from said FCC unit, a process consisting of heating the water in a hot water circuit by means of one or more process fluids originating from units placed upstream and/or downstream of the FCC unit and called hot fluids, one of these fluids being constituted by the overhead vapours from the fractionation column connected to the mild hydrocracking unit.

First claim

The invention claimed is:

1. A process for heating a reboiler of a propane/propylene separation column system which is fed with a C 3 cut from a fluid catalytic cracking unit, said process comprising:
heating water in a water circuit heat exchange with one or more process fluids originating from units positioned upstream and/or downstream of said fluid catalytic cracking, and then using the heated water in the water circuit to heat said reboiler of the propane/propylene separation column system, wherein said one or more process fluids are:
an overhead vapor stream from a fractionation column of a mild hydrocracking unit positioned upstream of said fluid catalytic cracking,
an overhead vapor stream from a stripper of a mild hydrocracking unit positioned upstream of said fluid catalytic cracking unit, and/or
effluent from a hydrodesulphurization reactor of a fluid catalytic cracking gasoline hydrotreatment positioned downstream of said fluid catalytic cracking unit, after said effluent undergoes heat exchange with a feedstock of the hydrodesulphurization reactor and with a feedstock of a selective hydrogenation reactor.

2. The process according to claim 1 , wherein the water is also heated in the water circuit by at least one fluid selected from the following fluids:
an overhead vapor stream from a main fractionation column of said fluid catalytic cracking unit,
a vapor stream originating from a stage of a cracked gas compressor,
a gasoline stream originating from a debutanizer of said fluid catalytic cracking unit,
an upper circulating reflux from a main fractionation column of said fluid catalytic cracking unit,
an overhead vapor stream from a gasoline separation column of said fluid catalytic cracking unit,
a light cycle oil originating from the main fractionation column of said fluid catalytic cracking unit.

3. The process according to claim 1 , wherein said propane/propylene separation column system is also fed with a C 3 cut originating from a propylene producing unit.

4. The process according to claim 3 , wherein said propylene producing unit is a unit for conversion of olefins to propylene.

5. The process according to claim 1 , wherein
said propane/propylene separation column system comprises a first propane/propylene separation column having a top and a bottom, and a second propane/propylene separation column having a top and a bottom,
wherein liquid from the bottom of the second propane/propylene separation column is pumped to the top of the first propane/propylene separation column, overhead vapor from the second propane/propylene separation column is condensed with cooling water and then sent to a reflux drum of the second propane/propylene separation column, propylene is recovered from the top of the second propane/propylene separation column, and propane is recovered from the bottom of the first propane/propylene separation column,
wherein the water heated in the water circuit is heated by heat exchange with said one or more process fluids via heat exchangers which are arranged in parallel,
wherein the reboiler of the propane/propylene separation column system that is heated by the water circuit is a reboiler at the bottom of the first propane/propylene separation column, and
wherein said water circuit is also used to heat an intermediate reboiler of the first propane/propylene separation column.

6. The process according to claim 1 , wherein said water in said water circuit is heated by heat exchange with said overhead vapor stream from said fractionation column of said mild hydrocracking unit.

7. The process according to claim 1 , wherein said water in said water circuit is heated by heat exchange with said overhead vapor stream from said stripper of said mild hydrocracking unit.

8. The process according to claim 1 , wherein said water in said water circuit is heated by heat exchange with said effluent from said hydrodesulphurization reactor of said fluid catalytic cracking gasoline hydrotreatment.

9. The process according to claim 1 , wherein said propane/propylene separation column system comprises a plurality of columns arranged in series, and wherein said reboiler that is heated by said water circuit is in the first column in the series of columns.

10. The process according to claim 9 , wherein said reboiler is a bottom reboiler in said first column in the series of columns, and wherein said first column in the series of columns also comprises an intermediate reboiler, and said intermediate reboiler is also heated by said water circuit.

11. The process according to claim 10 , wherein the water of said water circuit is cooled in said bottom reboiler from 91° C. to 75° C., and the water of said water circuit is cooled in said intermediate reboiler from 75° C. to 65° C.

Assignees

• Ifp Energies Now

Inventors

• Digne Romina
• Dreux Heloise
• Feugnet Frederic
• Lambert Nicolas

Classifications

• C10G69/04

  including at least one step of catalytic cracking in the absence of hydrogen · CPC title

• C10G45/72

  Controlling or regulating · CPC title

• F25J3/0214 Primary

  Liquefied natural gas · CPC title

• B01D3/143

  by two or more of a fractionation, separation or rectification step · CPC title

• C10G7/12

  Controlling or regulating · CPC title