Chemical-looping combustion method with ashes and fines removal at the oxidation zone outlet and plant using same

Patent metadata

Field	Value
Publication number	US-9494315-B2
Application number	US-201214355858-A
Country	US
Kind code	B2
Filing date	Oct 29, 2012
Priority date	Dec 2, 2011
Publication date	Nov 15, 2016
Grant date	Nov 15, 2016

Abstract

The invention relates to a method for chemical-looping combustion of a solid hydrocarbon-containing feedstock, wherein the ashes and fines are removed at the outlet of reactive oxidation zone R 1 by sending transported phase ( 5 ) coming from reactive zone R 1 , comprising gas and solid, to a gas-solid separation zone S 2 , then by sending solid stream ( 7 ) coming from gas-solid separation zone S 2 to a dense phase elutriation separation zone S 3 fluidized by a non-reducing gas ( 8 ) allowing the fines and the fly ashes to be separated from the oxygen-carrying material particles. Optionally, deeper separation is carried out in a dedusting zone S 5 arranged downstream from dense phase elutriation separation zone S 3.
The invention also relates to a chemical-looping combustion plant allowing the method according to the invention to be implemented.

First claim

The invention claimed is:

1. A method for chemical-looping combustion of a hydrocarbon feedstock of solid particles, wherein an oxygen-carrying material circulates in form of particles, comprising:
contacting hydrocarbon feedstock particles with the oxygen-carrying material particles in a reduction zone R 0 ,
contacting the oxygen-carrying material particles from the reduction zone R 0 with an oxidizing gas stream in a reactive oxidation zone R 1 ,
sending a transported phase from the reactive zone R 1 comprising gas and solid to a gas-solid separation zone S 2 so as to separate: a predominantly gaseous transported phase comprising fly ashes and oxygen-carrying material fines, and a solid stream comprising the major part of the fines, the fly ashes and the major part of the oxygen-carrying material particles,
sending the solid stream from the gas-solid separation zone S 2 to a dense fluidized phase elutriation separation zone S 3 fluidized by a non-reducing gas allowing to separate the fines and the fly ashes from the oxygen-carrying material particles so as to send a particle stream comprising the major part of the oxygen carrier particles to the reduction zone R 0 , and to discharge through a discharge line a predominantly gaseous effluent comprising the major part of the fly ashes and of the oxygen-carrying material fines.

2. A method as claimed in claim 1 , wherein the oxygen-carrying particles are circulated in a loop in the reactive zone R 1 by means of a line allowing to recycle the oxygen-carrying particles sedimented in the dense fluidized phase from the bottom of the separation zone S 3 to a lower part of the reactive zone R 1 .

3. A method as claimed in claim 1 , wherein heat is recovered in the dense fluidized phase formed in the bottom of the dense fluidized phase elutriation separation zone S 3 by means of a heat exchanger E 4 .

4. A method as claimed in claim 1 , wherein dense fluidized phase elutriation separation zone S 3 is fluidized with a fluidization rate ranging between 0.5 and 1 m/s.

5. A method as claimed in claim 1 , wherein the oxygen-carrying material particles initially comprise less than 10% particles of diameter below 100 microns.

6. A method as claimed in claim 1 , wherein:
the predominantly gaseous effluent from dense fluidized phase elutriation separation zone S 3 is sent to a dedusting zone S 5 in order to discharge a gas stream containing the major part of the ashes and of the fines and a particle stream comprising the major part of the oxygen-carrying material, said particle stream being sent through a transport line to reduction zone R 0 .

7. A plant for carrying out chemical-looping redox combustion of a solid hydrocarbon feedstock according to the method as claimed in claim 1 , said plant comprising at least:
a reduction zone R 0 ,
a reactive oxidation zone R 1 provided with feed means supplying oxygen-carrying particles coming from the reduction zone R 0 , feed means supplying oxidizing fluidization gas, and a discharge line for discharging a transported phase comprising gas and solid particles,
a gas-solid separation zone S 2 arranged downstream from the reactive zone R 1 , supplied by said discharge line and comprising a line for discharging a predominantly gaseous transported phase and a discharge line for discharging a solid stream comprising the major part of the oxygen-carrying material,
a dense phase elutriation separation zone S 3 arranged downstream from gas-solid separation zone S 2 , comprising an intake for said solid stream, a line allowing a fluidization gas to be supplied, a line for carrying to the reduction zone R 0 a solid particle stream rich in oxygen-carrying particles, and a line for discharging a gas stream rich in fly ashes.

8. A plant as claimed in claim 7 , comprising a heat exchanger E 4 in a dense fluidized phase formed in a bottom of the dense fluidized phase elutriation separation zone S 3 .

9. A plant as claimed in claim 7 , comprising a line coming from the fluidized dense phase elutriation separation zone S 3 for recycling to the reactive zone R 1 a particle stream comprising part of the oxygen-carrying particles separated in the dense phase elutriation separation zone S 3 .

10. A plant as claimed in claim 7 , comprising a dedusting zone S 5 downstream from the dense phase elutriation separation zone S 3 , provided with an intake line for receiving a predominantly gaseous effluent coming from the dense phase elutriation separation zone S 3 , a discharge line allowing to discharge a gas stream containing the major part of the ashes and the fines, and a transport line for carrying to the reduction zone R 0 a particle stream comprising the major part of the oxygen-carrying material.

Assignees

• Total Sa
• Ifp Energies Now

Inventors

• Guillou Florent
• Gauthier Thierry
• Hoteit Ali
• Rifflart Sebastien

Classifications

• F23C10/01 Primary

  in a fluidised bed of catalytic particles · CPC title

• F23B99/00

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

• F23C2900/99008

  Unmixed combustion, i.e. without direct mixing of oxygen gas and fuel, but using the oxygen from a metal oxide, e.g. FeO · CPC title

• F23C99/00 Primary

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

• F23C10/24

  Devices for removal of material from the bed (devices for controlling the level of the bed or the amount of material in the bed F23C10/30) · CPC title