Process and apparatus for chemical looping redox combustion with control of the heat exchanges

Patent metadata

Field	Value
Publication number	US-10184657-B2
Application number	US-201515319603-A
Country	US
Kind code	B2
Filing date	Jun 18, 2015
Priority date	Jun 19, 2014
Publication date	Jan 22, 2019
Grant date	Jan 22, 2019

Abstract

The invention relates to a process and to a unit for chemical looping oxidation-reduction combustion of a hydrocarbon feed, wherein heat exchanges are controlled through a level variation of a dense fluidized bed of active mass particles in an external heat exchanger (E 1 , E 2 ), positioned on a transport line carrying particles circulating between a reduction zone ( 210 ) and an oxidation zone ( 200 ) for the particles in the chemical loop. The bed level variation is allowed through controlled application of a pressure drop on a fluidization gas outlet in the heat exchanger, said pressure drop being compensated by the level variation of an active mass particle bed in a reservoir zone provided on the particle circuit in the chemical loop.

First claim

The invention claimed is:

1. A process for chemical looping oxidation-reduction combustion of a hydrocarbon feed wherein a redox active mass in form of particles circulates between an oxidation zone and a reduction zone so as to form a circuit, wherein:
combustion of said hydrocarbon feed is carried out by contacting with the redox active mass particles in the reduction zone,
the redox active mass particles from the reduction zone are oxidized by contacting with an oxidizing gas stream in the oxidation zone,
the particles are sent to at least one heat exchanger positioned on a particle transport line between the reduction zone and the oxidation zone, and a fluidization gas is sent into said exchanger so as to create a dense fluidized bed comprising the active mass particles, said heat exchanger comprising a heat exchange surface in contact with the fluidized bed,
the heat recovery is controlled in said at least one heat exchanger by varying the fluidized bed level through controlled application of a pressure drop on a fluidization gas outlet positioned in an upper part of the heat exchanger,
wherein the active mass particles are sent to a reservoir zone provided upstream from the heat exchanger, the reservoir zone and the heat exchanger being contained in a single assembly,
the pressure drop applied in the heat exchanger is compensated by a level variation of an active mass particle bed in the reservoir zone communicating with the fluidized bed of the heat exchanger.

2. A process as claimed in claim 1 , wherein:
the reservoir zone and the heat exchanger are contained in a single enclosure provided with a wall that vertically separates the enclosure into a first part forming the reservoir zone and a second part forming the heat exchanger,
the reservoir zone communicating with the fluidized bed of the heat exchanger through a passage in the wall of the enclosure.

3. A process as claimed in claim 1 , wherein the active mass particles are sent to the at least one heat exchanger through an inlet leg of the heat exchanger, said inlet leg forming the reservoir zone.

4. A process as claimed in claim 1 , wherein the active mass particles are discharged from the at least one heat exchanger through a pipe arranged in the lower part of the heat exchanger, said pipe having the form of a siphon.

5. A process as claimed in claim 1 , wherein an opening of a mechanical valve positioned on the fluidization gas outlet of the heat exchanger is controlled for controlled application of the pressure drop.

6. A process as claimed in claim 1 , wherein a temperature of a controlled pressure drop application means positioned on the fluidization gas outlet outside said heat exchanger is controlled.

7. A process as claimed in claim 6 , wherein said controlled pressure drop application means are cooled by contacting with a cooling fluid circulation circuit.

8. A process as claimed in claim 1 , wherein the heat exchange is carried out on a transport line carrying the active mass particles from the reduction zone to the oxidation zone.

9. A unit for chemical looping oxidation-reduction combustion of a hydrocarbon feed as claimed in claim 1 , comprising:
a reduction zone for combustion of the hydrocarbon feed on contact with an active mass in form of particles,
an oxidation zone for oxidation of the active mass particles from the reduction zone on contact with an oxidizing gas stream,
at least one active mass particles transport line between the reduction zone and the oxidation zone,
a heat exchange control device comprising:
a heat exchanger positioned on said at least one transport line and comprising:
an inlet for an incoming stream of active mass particles,
fluidization gas injection means for forming a dense fluidized bed of active mass particles,
an outgoing fluidization gas outlet provided in an upper part of the heat exchanger, said outlet comprising controlled pressure drop application means,
an outlet for an outgoing stream of active mass particles provided in a lower part of the heat exchanger,
a heat exchange surface in contact with the dense fluidized particle bed,
a reservoir zone for compensating the pressure drop applied on the fluidization gas outlet of the heat exchanger, said reservoir zone being positioned on the particle circuit of the chemical loop provided between the reduction zone and the oxidation zone.

10. A unit as claimed in claim 9 , wherein the heat exchanger and the reservoir zone comprises a single enclosure provided with a wall that vertically separates said enclosure into a first part forming the reservoir zone upstream from a second part forming the heat exchanger, the wall comprising a passage for the active mass particle bed from the reservoir zone to the heat exchanger, the particles flowing in through a pipe provided in the upper part of the reservoir zone.

11. A unit as claimed in claim 9 , wherein the active mass particles flow into the heat exchanger through an inlet leg of the heat exchanger, said inlet leg forming the reservoir zone.

12. A unit as claimed in claim 9 , wherein the outgoing particle stream in the heat exchanger flows out through a pipe provided in the lower part of the heat exchanger, said pipe having the form of a siphon.

13. A unit as claimed in claim 9 , wherein controlled application of a pressure drop is achieved through a mechanical valve positioned on fluidization gas outlet of the heat exchanger.

14. A unit as claimed in claim 9 , wherein the controlled pressure drop application means are arranged on the fluidization gas outlet outside said heat exchanger.

15. A unit as claimed in claim 14 , wherein the unit comprises means for cooling said controlled pressure drop application mean.

16. A unit as claimed in claim 9 , comprising:
a first particle transport line for carrying the active mass particles from the reduction zone to the oxidation zone,
a second particle transport line for carrying the active mass particles from the oxidation zone to the reduction zone, and
wherein heat exchanger is positioned on at least the first particle transport line.

Assignees

• Ifp Energies Now
• Total Raffinage Chimie

Inventors

• Yazdanpanah Mahdi
• Gauthier Thierry
• Guillou Florent

Classifications

• B01J2208/0061

  Controlling the level · CPC title

• B01J8/388

  externally, i.e. the particles leaving the vessel and subsequently re-entering it · CPC title

• B01J8/30 Primary

  the edge of a lower bed projecting beyond the edge of the superjacent bed · CPC title

• F23C99/00 Primary

  Subject-matter not provided for in other groups of this subclass · CPC title

• B01J8/26 Primary

  with two or more fluidised beds, e.g. reactor and regeneration installations · CPC title