The disclosure provides a tri-metallic ferrite oxygen carrier for the chemical looping combustion of carbonaceous fuels. The tri-metallic ferrite oxygen carrier comprises Cu.sub.xFe.sub.yMn.sub.zO.sub.4-δ, where Cu.sub.xFe.sub.yMn.sub.zO.sub.4-δ is a chemical composition. Generally, 0.5≦x≦2.0, 0.2≦y≦2.5, and 0.2≦z≦2.5, and in some embodiments, 0.8≦x≦1.2, y≦1.2, and z≧0.8. The tri-metallic ferrite oxygen carrier may be used in various applications for the combustion of carbonaceous fuels, including as an oxygen carrier for chemical looping combustion.

The invention relates to a method and to a plant for chemical looping oxidation-reduction combustion (CLC) of a gaseous hydrocarbon feed, for example natural gas essentially containing methane. According to the invention, catalytic reforming of the feed is performed within the reduction zone where combustion of the feed is conducted on contact with an oxidation-reduction active mass in form of particles. The reforming catalyst comes in form of untransported fluidized particles within the reduction zone. The catalyst thus confined in the reduction zone does not circulate in the CLC loop.

The invention relates to a method and to a plant for chemical looping oxidation-reduction combustion (CLC) of a gaseous hydrocarbon feed, for example natural gas essentially containing methane. According to the invention, catalytic reforming of the feed is performed within the reduction zone where combustion of the feed is conducted on contact with an oxidation-reduction active mass in form of particles. The reforming catalyst comes in form of untransported fluidized particles within the reduction zone. The catalyst thus confined in the reduction zone does not circulate in the CLC loop.

A device with annular spouted fluidized bed can be used for carrying out the majority of the technical processes carried out in fluidized bed devices. The reaction chamber of the device has, throughout at least a part of its height, a downwardly tapering funnel shape with step-structured inner surface. The shape of the reaction chamber, together with the tangential admission thereto of fluidized and other gases, makes it possible to create, in the reaction chamber, an adjustable toroidal fluidized bed, in which the rotation rate of the particles of the material undergoing treatment can be adjusted in both horizontal and vertical planes, and also makes it possible to control the dwell time of particles of different sizes in the reaction zone, the intensity with which materials are treated, and other process parameters.

A device with annular spouted fluidized bed can be used for carrying out the majority of the technical processes carried out in fluidized bed devices. The reaction chamber of the device has, throughout at least a part of its height, a downwardly tapering funnel shape with step-structured inner surface. The shape of the reaction chamber, together with the tangential admission thereto of fluidized and other gases, makes it possible to create, in the reaction chamber, an adjustable toroidal fluidized bed, in which the rotation rate of the particles of the material undergoing treatment can be adjusted in both horizontal and vertical planes, and also makes it possible to control the dwell time of particles of different sizes in the reaction zone, the intensity with which materials are treated, and other process parameters.

A device with annular spouted fluidized bed can be used for carrying out the majority of the technical processes carried out in fluidized bed devices. The reaction chamber of the device has, throughout at least a part of its height, a downwardly tapering funnel shape with step-structured inner surface. The shape of the reaction chamber, together with the tangential admission thereto of fluidized and other gases, makes it possible to create, in the reaction chamber, an adjustable toroidal fluidized bed, in which the rotation rate of the particles of the material undergoing treatment can be adjusted in both horizontal and vertical planes, and also makes it possible to control the dwell time of particles of different sizes in the reaction zone, the intensity with which materials are treated, and other process parameters.

A device with annular spouted fluidized bed can be used for carrying out the majority of the technical processes carried out in fluidized bed devices. The reaction chamber of the device has, throughout at least a part of its height, a downwardly tapering funnel shape with step-structured inner surface. The shape of the reaction chamber, together with the tangential admission thereto of fluidized and other gases, makes it possible to create, in the reaction chamber, an adjustable toroidal fluidized bed, in which the rotation rate of the particles of the material undergoing treatment can be adjusted in both horizontal and vertical planes, and also makes it possible to control the dwell time of particles of different sizes in the reaction zone, the intensity with which materials are treated, and other process parameters.

The invention relates to a method for operating a fluidized bed boiler (6), comprising the steps of: a) providing fresh ilmenite particles having a shape factor of 0.8 or lower as bed material to the fluidized bed boiler (6); b) carrying out a fluidized bed combustion process; c) removing at least one ash stream comprising ilmenite particles from the fluidized bed boiler; d) separating ilmenite particles from the at least one ash stream, wherein the separation includes a step of using a magnetic separator (12) comprising a field strength of 2,000 Gauss or more; e) recirculating separated ilmenite particles into the bed of the fluidized bed boiler; wherein the average residence time of ilmenite particles in the fluidized bed is 100 h or more.

The invention relates to a method for operating a fluidized bed boiler (6), comprising the steps of: a) providing fresh ilmenite particles having a shape factor of 0.8 or lower as bed material to the fluidized bed boiler (6); b) carrying out a fluidized bed combustion process; c) removing at least one ash stream comprising ilmenite particles from the fluidized bed boiler; d) separating ilmenite particles from the at least one ash stream, wherein the separation includes a step of using a magnetic separator (12) comprising a field strength of 2,000 Gauss or more; e) recirculating separated ilmenite particles into the bed of the fluidized bed boiler; wherein the average residence time of ilmenite particles in the fluidized bed is 100 h or more.

The invention relates to a CLC plant for the combustion of solid hydrocarbon feedstocks generating particles of unburnt residues, comprising a solid/solid separator above the combustion reactor in order to efficiently separate the particles of the oxygen-carrying solid from the particles of unburnt residues contained in the gas/solid mixture (14) exiting from the combustion reactor. The chamber (1) of the solid/solid separator, the combustion reactor and the inlet (2) for the gas/solid mixture (14) of the chamber have a parallelepiped shape. The inlet (2) is equipped at its top with means (3) for distribution of said gas/solid mixture in the chamber which extend over the entire length of the inlet, improving the solid/solid separation.