CIRCULAR INCINERATION PLANT AND PROCESS WITH A CYCLONE AIR REACTOR

Description

technical field

[0001] The present invention relates to the field of chemical loop combustion of hydrocarbon feedstocks by chemical loop redox (CLC) operating in a fluidized bed, capable of producing energy, synthesis gas, and / or hydrogen. In particular, the present invention relates to a new CLC installation and process in which the oxidation of the oxygen carrier is carried out in a cyclone reactor. Previous technique

[0002] A CLC process involves carrying out redox reactions with an active mass, typically a metal oxide, also called an oxygen carrier, to break down the combustion reaction into two successive reactions: a first oxidation reaction of the oxygen carrier in contact with an oxidizing gas, typically air, and a second reduction reaction of the oxygen carrier in contact with the fuel to be burned. The CLC process is similar to oxycombustion, with the main difference being that the combustion is not fueled by a dedicated flow of pure oxygen, as in oxycombustion, but by the oxygen carrier acting as an oxygen transporter.

[0003] Typically, particles are oxidized in contact with an oxidizing gas, such as air, in a first reaction zone called the oxidation reactor or air reactor. They are then transported to a second reaction zone called the combustion reactor or fuel reactor, where they are brought into contact with a solid, liquid, or gaseous hydrocarbon feedstock that is to be burned. The oxygen carried by the oxygen carrier particles fuels the combustion of the feedstock in the fuel reactor. This results in a gaseous effluent formed by the combustion of the feedstock and a stream of reduced particles. The particles are returned to the air reactor to be oxidized again, thus closing the loop.

[0004] CLC processes are known in the field of energy production, gas turbines, boilers and furnaces, particularly for the oil, glass and cement industries.

[0005] In particular, the CLC process makes it possible to produce energy (steam, electricity, etc.) by recovering the heat released by combustion reactions while facilitating the capture of carbon dioxide (CO2) emitted during combustion through the production of CO2-rich flue gases. In the CLC process, the combustion gases produced in the fuel reactor are indeed devoid of oxygen and nitrogen. CO2 capture can occur after condensation of the steam and compression of the flue gases, and it can then be stored, for example in geological formations, used as a reagent in other processes, or utilized, for example, to improve the efficiency of oil operations in enhanced oil recovery (EOR) or enhanced gas recovery (EGR) processes.

[0006] The CLC process can also produce synthesis gas, or even hydrogen, by controlling the combustion operating conditions (stoichiometric ratio and temperature) and implementing the necessary purification downstream of the combustion process. This combustion method can also produce a nitrogen-rich stream, corresponding to the depleted air obtained after the oxidation of the active mass in the air reactor. Depending on the degree of purity achieved, this nitrogen stream can be used in various applications, particularly in the petroleum industry. For example, it can be used in refineries as an inert gas in various oil refining processes or for treating production water, or as a gas injected into the subsoil in EOR processes.

[0007] In the context of increasing global energy demand, the CLC process therefore provides an attractive solution for capturing CO2 for sequestration or recovery in other processes, in order to limit the emission of greenhouse gases harmful to the environment.

[0008] The oxygen carrier is a solid material in the form of fluidizable particles, with a typical particle size between 50 µm and 500 µm. These particles are brought into contact with either the oxidizing gas or the feedstock in the reaction zones, using high-temperature fluidized beds, and are generally transported from one zone to another in a fluidized state. Circulating fluidized bed technology is commonly used to enable the continuous transfer of the oxygen carrier from its oxidized state in the air reactor to its reduced state in the fuel reactor.

[0009] In a CLC process, the air and fuel reactors each contain gas and solid phases which form a gas / solid mixture that can be upward. In the air reactor in particular, this mixture generally moves at high speed (several meters per second for the surface velocity of the gas, for example between 2 m / s and 15 m / s), the air reactor being typically a riser-type reactor, forming a substantially elongated and vertical conduit (for example with a diameter between 1 m and 6 m for a height between 10 m and 30 m), and operating in a dilute fluidized bed (rapid fluidization or pneumatic transport regime).

[0010] At the outlet of the air reactor, the gas / solid mixture is separated in a cyclone to separate the oxygen carrier from the depleted air. Cyclones or other gas / solid separation devices are also used at the outlet of the fuel reactor to separate the oxygen carrier from the combustion fumes.

[0011] The figure 1This represents a CLC installation according to the prior art. The oxygen carrier in its reduced form 400 is introduced into the air reactor 1000 and brought into contact with an air stream 100. The oxygen carrier solid reacts with the oxygen in the air to form a gas / solid mixture 101 composed of oxidized oxygen carrier solid and depleted air, i.e., air whose oxygen concentration has been reduced after reaction with the oxygen carrier. The mixture 101 is introduced into a cyclone 3001 which produces a gaseous effluent 110 consisting essentially of depleted air and a solid stream 102 consisting essentially of the oxygen carrier in its oxidized form. This solid stream 102 is introduced into the fuel reactor 2000 where it is brought into contact with a hydrocarbon feedstock 200 within a fluidized bed, typically by means of a fluidizing gas 300.Depending on the feedstock used, the fluidizing gas 300 can contribute to the gasification of the hydrocarbon feedstock 200, particularly if the latter is solid or liquid. The fluidizing gas 300 can be beneficial, but is not essential, if the hydrocarbon feedstock 200 introduced into the reactor is gaseous. The gaseous feedstock, which may be a gaseous hydrocarbon feedstock 200 introduced into the reactor 2000 or the product of the gasification of a solid or liquid hydrocarbon feedstock 200, reacts with the oxygen contained in the oxygen carrier. This results in a gas / solid mixture 301 comprising the reduced oxygen carrier, combustion fumes from the feedstock and the fluidizing gas, and possibly unburned gaseous or solid material.This gas / solid mixture 301 is separated in a gas / solid separation device 3002, typically a cyclone, into a solid stream comprising essentially the reduced oxygen carrier 400 and a gas mixture 310 comprising the combustion fumes and the fluidization gas.

[0012] Air and fuel reactors and their associated gas / solid separation devices are therefore key components of the CLC installation and process. The function performed by each is essential to the operation of the CLC, and any improvement to these elements can significantly increase the attractiveness of this CO2 capture energy production technology.

[0013] EP 2 644 994 A1 shows a chemical loop combustion system comprising a fuel reactor, an air reactor, and a post-oxidation reactor. Objectives and Summary of the Invention

[0014] In this context, the present invention aims to address the general problem of energy production by combustion of a hydrocarbon feedstock incorporating CO2 capture, and in particular aims to provide a more compact CLC installation compared to a conventional CLC installation as described above, and consequently potentially at a reduced capital expenditure (CAPEX). Another objective of the present invention is to enable the conversion of existing industrial combustion units, for example, those using a boiler, into chemical loop combustion units.

[0015] In this context, and to achieve at least one of the aforementioned objectives, among others, the present invention proposes, according to a first aspect, a CLC installation for a hydrocarbon feedstock using an oxygen-carrying solid in the form of particles comprising at least: a reduction reactor configured to operate in a fluidized bed and to carry out the combustion of said hydrocarbon feed in contact with said oxygen carrier; at least one cyclonic oxidation reactor configured to oxidize said reduced oxygen carrier from said reduction reactor by contacting it with an oxidizing gas and to separate said oxidized oxygen carrier from said oxygen-depleted oxidizing gas; circulation lines for said oxygen carrier between said reduction reactor and said at least one cyclonic oxidation reactor.

[0016] According to one or more embodiments, said at least one cyclonic oxidation reactor comprises: a cylindro-conical chamber comprising a cylindrical upper portion surmounting an inverted frustoconical lower portion, an inlet duct for a gas mixture comprising particles of the oxygen carrier and the oxidizing gas, said inlet duct being provided with a main injection duct for oxidizing gas and said inlet duct opening into said cylindrical upper portion; an outlet duct for an oxygen-depleted gas stream positioned at the top of the cylindrical upper portion; an outlet duct for a stream of oxygen carrier particles positioned at the bottom of the inverted frustoconical lower portion.

[0017] According to one or more embodiments, the installation comprises several cyclonic oxidation reactors configured to operate in series and / or in parallel.

[0018] According to one or more embodiments, the installation comprises two cyclonic oxidation reactors configured to operate in series.

[0019] According to one or more embodiments, the installation comprises at least two cyclonic oxidation reactors configured to operate in series, and wherein the outlet line of a second cyclonic oxidation reactor positioned downstream of a first cyclonic oxidation reactor is connected to the inlet line of said first cyclonic oxidation reactor to form the main injection line of oxidizing gas feeding said first cyclonic oxidation reactor.

[0020] According to one or more embodiments, the inlet pipe of said at least one cyclonic oxidation reactor is provided with at least one secondary oxidizing gas injection pipe, preferably disposed on a lower wall of said inlet pipe.

[0021] According to one or more embodiments, the installation includes a cyclone disposed downstream and directly connected to said reduction reactor, configured to receive a gas / solid mixture from said reduction reactor and to perform the separation between the reduced oxygen carrier and combustion fumes, said cyclone having an outlet line for the reduced oxygen carrier connected to said cyclonic oxidation reactor.

[0022] Depending on one or more embodiments, the installation comprises: a solid / solid separation device disposed downstream and directly connected to said reduction reactor, said solid / solid separation device being configured to operate in a fluidized bed, to receive a gas / solid mixture from said reduction reactor, and to perform the separation between the particles of the reduced oxygen carrier and the unburned particles contained in said gas / solid mixture, and at least one cyclone disposed downstream of said solid / solid separation device and configured to receive a gas stream comprising said unburned particles and to perform the separation between said unburned particles and combustion fumes, said cyclone preferably comprising an outlet duct for said unburned particles connected to said reduction reactor.

[0023] According to another aspect, the present invention proposes a CLC process for a hydrocarbon feedstock using a solid oxygen carrier in the form of particles, in which: The hydrocarbon feedstock is combusted by contacting the oxygen carrier within a reduction reactor operated in a fluidized bed; the oxygen carrier that has been in the reduction reactor is oxidized by contacting it with an oxidizing gas, preferably air, within at least one cyclonic oxidation reactor, and the oxidized oxygen carrier is separated from the oxygen-depleted oxidizing gas within the cyclonic oxidation reactor before the oxidized oxygen carrier is returned to the reduction reactor.

[0024] Depending on one or more implementations: an oxidizing gas and the oxygen carrier from the reduction reactor are mixed in an inlet pipe of said at least one cyclonic oxidation reactor; said gas mixture including the oxygen carrier is sent into an upper cylindrical portion of a cylindro-conical chamber of said cyclonic oxidation reactor, said cylindro-conical chamber having the upper cylindrical portion surmounting an inverted frustoconical lower portion; said oxygen carrier is oxidized in contact with the oxidizing gas and the oxidized oxygen carrier is separated from the oxygen-depleted oxidizing gas within said cylindro-conical chamber; said oxygen-depleted oxidizing gas is discharged through an outlet pipe positioned at the top of the upper cylindrical portion; and a stream of oxidized oxygen carrier is discharged through an outlet pipe positioned at the bottom of the inverted frustoconical lower portion.

[0025] Depending on one or more implementations, the oxidation of the oxygen carrier from the reduction reactor is carried out in two cyclonic oxidation reactors operated in series and / or in parallel.

[0026] According to one or more implementations, the oxygen-depleted oxidizing gas discharged through the outlet pipe of a second cyclonic oxidation reactor positioned downstream of a first cyclonic oxidation reactor is used to form the gas mixture in the inlet pipe of said first cyclonic oxidation reactor and to oxidize the oxygen carrier from the reduction reactor within said first cyclonic oxidation reactor.

[0027] According to one or more implementations, a gas / solid mixture from the reduction reactor is sent into a cyclone disposed downstream and directly connected to said reduction reactor to effect a separation between the reduced oxygen carrier and combustion fumes contained in said gas / solid mixture, and the reduced oxygen carrier is sent to said at least one cyclonic oxidation reactor.

[0028] According to one or more implementations, the hydrocarbon feedstock is a solid feedstock in particulate form, preferably chosen from the list consisting of coal, coke, petcoke, biomass, oil sands and municipal solid waste, and in which: a gas / solid mixture from the reduction reactor is sent into a solid / solid separation device directly connected to said reduction reactor and operated in a fluidized bed to carry out the separation between the reduced oxygen carrier and unburned particles contained in said gas / solid mixture; a gas stream from the solid / solid separator and containing said unburned particles is sent into at least one cyclone to carry out the separation between said unburned particles and combustion fumes; the reduced oxygen carrier is sent to said at least one cyclonic oxidation reactor, preferably by means of an L-valve; optionally said unburned particles are sent to said reduction reactor.

[0029] According to one or more implementations, the residence time of the oxygen carrier in said at least one oxidation reactor is less than or equal to 30 seconds.

[0030] Other objects and advantages of the invention will become apparent from the following description of particular embodiments of the invention, given by way of non-limiting examples, the description being made with reference to the attached figures described below. List of figures

[0031] There figure 1 The diagram already described schematically represents a CLC installation according to prior art. figure 2 is a diagram of the CLC installation according to one or more embodiments of the present invention comprising a cyclonic oxidation reactor. figure 3 is a diagram of the CLC installation according to one or more embodiments of the present invention comprising two successive cyclonic oxidation reactors. figure 4is a diagram of the CLC installation according to one or more embodiments of the present invention comprising two successive cyclonic oxidation reactors, the first of which is supplied with an oxygen-depleted oxidizing gas from the second cyclonic oxidation reactor. figure 5 is a diagram of the CLC installation according to one or more embodiments of the present invention adapted to the combustion of a solid hydrocarbon feedstock, comprising a cyclonic oxidation reactor and a solid / solid separation device at the outlet of the fuel reactor.

[0032] In the figures, the same references designate identical or analogous elements. Description of the implementation methods

[0033] The present invention proposes a new CLC installation and process for a hydrocarbon feedstock in which the oxidation reactor has a cyclone structure and is referred to as a cyclonic oxidation reactor in this description. Its function is twofold: to oxidize the oxygen carrier particles during the CLC process and to separate the oxidized carrier particles from the gas used for their oxidation before they are returned to the reduction reactor. Such a cyclonic oxidation reactor advantageously combines the functions performed in a conventional CLC installation by two devices: the oxidation reactor, which operates in a fluidized bed and is generally a riser, and the cyclone at the outlet of the oxidation reactor, which separates the carrier particles from the depleted air. The CLC installation according to the invention is thus more compact, and investment costs are reduced.The method according to the invention is particularly suitable for implementing the installation according to any of the variants or combinations of variants described below.

[0034] The invention relates to a CLC installation and process as described in detail below. However, the scope of the invention remains unchanged by implementing the cyclonic oxidation reactor described for the CLC installation / process in other chemical loop redox installations / processes based on circulating fluidized bed technology such as chemical loop reforming (CLR) installations / processes or CLOU installations / processes (Chemical Looping Oxygen Uncoupling).

[0035] In this description, reference is made to chemical loop redox (CLC, CLR, CLOU) installations / processes, in particular CLC, in circulating fluidized bed, i.e. in which fluidization regimes of the oxygen-carrying solid in the form of particles allow its transport and circulation in the installation.

[0036] In this description, the terms "oxygen-carrying solid," "oxygen carrier," "oxygen-transporting material," "redox active mass," or simply "active mass" are equivalent. The redox mass is considered active in relation to its reactive capabilities, meaning that it is able to perform its role as an oxygen carrier in the CLC process by capturing and releasing oxygen.

[0037] It is important to note that, generally speaking, the terms oxidation and reduction are used in relation to the oxidized or reduced state of the oxygen carrier, respectively. The cyclonic oxidation reactor, also called an air cyclone reactor, is the one in which the oxygen carrier is oxidized and separated from the oxidizing gas used for its oxidation. The reduction reactor, also called a fuel oil reactor or combustion reactor, is the one in which the oxygen carrier is reduced. The reduction reactor operates as a fluidized bed reactor, the cyclonic oxidation reactor functions hydrodynamically like a conventional cyclone, and the oxygen carrier circulates between the cyclonic oxidation reactor and the reduction reactor. Circulating fluidized bed technology is used to enable the continuous transition of the oxygen carrier from its oxidized state in the cyclonic oxidation reactor to its reduced state in the reduction reactor.

[0038] In the following description and in the claims, the positions (“bottom”, “top”, “above”, “below”, “horizontal”, “vertical”, “lower half”, etc.) of the various elements are defined in relation to the reactors and various devices of the installation in the operating position.

[0039] In this description, the term "include" is synonymous with (means the same as) "include" and "contain," and is inclusive or open-ended, not excluding other elements not mentioned. It is understood that the term "include" includes the exclusive and closed term "consist."

[0040] In this description, the expression "between ... and ..." means that the limit values ​​of the interval are included in the range of values ​​described, unless otherwise specified.

[0041] Furthermore, in this description, the terms "essentially" or "substantially" correspond to an approximation of ±5%, preferably ±1%, and most preferably ±0.5%. For example, an effluent consisting essentially of or made up of compounds A corresponds to an effluent comprising at least 95% by weight of compounds A.

[0042] Embodiments of the CLC installation and process are described in detail below. Numerous specific details are presented to provide a more thorough understanding of the invention. However, it will be apparent to those skilled in the art that the CLC installation and process can be implemented without all of these specific details. In other cases, well-known features have not been described in detail to avoid unnecessarily complicating the description.

[0043] With reference to the figure 2The CLC installation according to one or more embodiments of the present invention comprises a reduction reactor 2000 configured to operate in a fluidized bed and to carry out the combustion of a hydrocarbon feedstock 200 in contact with an oxygen carrier in the form of particles 102, in its reduced state. The installation also comprises a cyclonic oxidation reactor 3200 configured, on the one hand, to oxidize the reduced oxygen carrier 400 from the reduction reactor by contacting it with an oxidizing gas 100, and on the other hand, to separate the oxidized oxygen carrier from the oxygen-depleted oxidizing gas 110. In other words, the cyclonic oxidation reactor simultaneously performs two functions in a single device: the oxidation of the oxygen carrier and the separation of the oxygen carrier from the oxidizing gas. The installation also comprises oxygen carrier circulation lines between the reduction reactor 2000 and the cyclonic oxidation reactor 3200.

[0044] The oxygen carrier 400, which has been in the reduction reactor 2000, is oxidized by contacting it with the oxidizing gas 100 in the cyclonic oxidation reactor 3200. The oxidized oxygen carrier and the oxygen-depleted oxidizing gas are then separated within the cyclonic oxidation reactor 3200 before the oxidized oxygen carrier is returned to the reduction reactor 2000. The cyclonic oxidation reactor 3200 is described in detail later, after the description of the reduction reactor 2000.

[0045] For the sake of simplicity, the representation of the figure 2does not include all the equipment that may be part of the CLC installation. Other devices than those shown, in particular for solid / gas separation, solid / solid separation, heat exchange, pressurization, gas sealing between reactors, i.e. sealing of oxidizing and reducing atmospheres (e.g. siphons), solid storage, control of solid flows (e.g. mechanical or pneumatic valves) or possible recirculation of matter around the oxidation and combustion reactors, may be implemented.

[0046] In the reduction reactor 2000, the hydrocarbon feed 200 is brought into contact in co-current with the oxygen carrier in the form of particles 102 to achieve the combustion of said feed by reduction of the oxygen carrier.

[0047] The oxygen carrier MxOy, where M represents a metal, is reduced to the state MxOy-2n-m / 2, via the hydrocarbon charge CnHm, which is correspondingly oxidized to CO2 and H2O, according to reaction (1) below, or possibly to a mixture of CO2 and H2 depending on the proportions used. [Math 1] CnHm + MxOy → n CO 2 + m / 2 H 2 O + M x O y-2n-m / 2

[0048] The total combustion of the hydrocarbon charge is generally the target.

[0049] The combustion of charge 200 in contact with the oxygen carrier is carried out at a temperature generally between 600°C and 1400°C, preferably between 800°C and 1000°C. The contact time varies depending on the type of fuel used. It typically varies between 1 second and 20 minutes, for example preferably between 1 and 10 minutes, and more preferably between 1 and 8 minutes for a solid or liquid charge, and for example preferably from 1 to 20 seconds for a gaseous charge.

[0050] The hydrocarbon feedstocks (or fuels) processed may be solid, gaseous, or liquid, and preferably solid or gaseous. Solid feedstocks may be selected from coal, coke, petroleum coke (also known as "pet-coke"), biomass, oil sands, hard pitch (or deasphalting pitch), and municipal solid waste. Gaseous feedstocks are preferably composed primarily of methane, for example, natural gas or biogas. Liquid feedstocks may be selected from petroleum, bitumen, diesel, gasoline, and pitch. Depending on their melting point, pitches may be considered either a solid or a liquid feedstock. Preferably, the hydrocarbon feedstock processed is a solid or gaseous feedstock, as described above.

[0051] The reduction reactor operates as a fluidized bed. It includes at least one fluidizing gas injection system. Depending on the hydrocarbon feedstock used, the fluidizing gas can contribute to its gasification, particularly if it is solid or liquid. In the reduction reactor, the fluidizing gas can be CO₂, which may be CO₂ produced during combustion and recycled, or steam.

[0052] The 2000 reduction reactor is preferably configured to include a dense fluidized bed. Preferably, the surface velocity of the gas in the dense fluidized bed of the reduction reactor, also referred to here as the operational gas surface velocity Ug, is between 0.1 m / s and 3 m / s, preferably between 0.3 m / s and 2 m / s.

[0053] As an example, the 2000 reduction reactor can have a diameter DR ranging from 1 m to 10 m. Preferably, the reduction reactor has a height-to-diameter ratio (HR to DR) between 0.5 and 8, preferably between 1 and 5, and even more preferably between 2 and 4. The same applies to the ratio of the height of the dense fluidized bed in the reactor to the diameter of the reactor. A dense fluidized bed is defined as a gas / solid fluidized bed operating in a bubbling (also called a bubbling or turbulent) regime. The solids volume fraction in such a dense fluidized bed is generally between 0.25 and 0.50.

[0054] In the case of solid hydrocarbon feedstock combustion, a sufficiently long contact time between the feedstock and the oxygen carrier particles is generally required to approach complete combustion. This involves an initial gasification phase of the solid feedstock, followed by combustion of the gasified feedstock. Both phases can be carried out in the dense fluidized bed of the reduction reactor. Alternatively, the first phase can be carried out in the dense fluidized bed of the reduction reactor, and the second phase in a separate combustion zone. This could be within the same reactor in a zone above the dense bed operating as a dilute fluidized bed, or in a separate reactor receiving the gasified feedstock and bringing it into contact with the oxygen carrier, either within a dense or dilute fluidized bed.

[0055] The 2000 reduction reactor can thus be configured to include a dilute fluidized bed. A dilute fluidized bed is defined as a gas / solid fluidized bed operating under rapid fluidization or pneumatic conveying conditions. The solids volume fraction is generally less than 0.25.

[0056] In the case of chemical loop combustion of gaseous feeds for example, the contact time required between the oxygen carrier and the feed being less important than in the case of solid or liquid feeds, a reactor or part of a reactor of the "riser" type, forming a substantially elongated and vertical conduit, and operating in a dilute fluidized bed, may suffice to carry out the combustion of the feed, and transport the particles.

[0057] In the reactor or the part of the reduction reactor operating in dilute fluidized bed, the velocity is preferably greater than 3 m / s and less than 30 m / s, more preferably between 5 and 15 m / s, so as to facilitate the transport of all the particles while minimizing pressure losses in order to optimize the energy efficiency of the process.

[0058] The geometry of the reduction reactor can be parallelepiped, typically a rectangular parallelepiped, cylindrical, or any other three-dimensional geometry, preferably with rotational symmetry. Cylindrical refers to a cylinder of revolution. For example, the reduction reactor may be cylindrical or rectangular in shape. In the latter case, the reactor diameter DR should be understood as an equivalent diameter (equivalent cross-section).

[0059] The materials used to make the reactor and its constituent elements (inlet(s), outlet(s), etc.) can be chosen from refractory materials, for example refractory concrete, refractory brick or ceramic, high temperature steels, for example Hastelloy ®< , Incoloy ®< , Inconel ®< or Manaurite ®< , or conventional steels, for example stainless steel or carbon steel combined with refractory materials or combined with cooling means such as tubes in which a heat transfer fluid circulates.

[0060] A gas / solid mixture 301 comprising the gases from the combustion, also called combustion fumes in this description, and the oxygen carrier particles is discharged from the top of the reduction reactor 2000. A cyclone-type gas / solid separation system 3002, comprising one or more cyclones in series and / or in parallel, is disposed downstream and connected directly, i.e. without any other enclosure or intermediate device, to the reduction reactor 2000, and allows the combustion gases 310, also called combustion fumes, to be separated from the solid oxygen carrier particles in their most reduced state 400.In the case of the presence of unburned material which may occur if the hydrocarbon feed is solid, a solid / solid separation device allowing the unburned material particles to be separated from the active mass particles can be implemented at the outlet of the reduction reactor, as described below for other embodiments in relation to the . figure 5 .

[0061] The oxygen carrier particles 400, having stayed in the reduction reactor 2000 and been separated from the combustion gases, are sent to the cyclonic oxidation reactor 3200 to be re-oxidized and separated.

[0062] The 3200 cyclone oxidation reactor comprises: a cylindro-conical chamber having a cylindrical upper portion above an inverted frustoconical lower portion (the frustoconical portion is said to be inverted because the cone section of the smallest diameter is in the lower part of the cylindro-conical chamber, and the cone section of the largest diameter is in the upper part connected to the cylindrical upper portion, when the reactor is in operation), an inlet line for a gas mixture 120 comprising particles of the oxygen carrier 400 and of the oxidizing gas 100, this inlet line having a main injection duct for oxidizing gas 100 and opening into the cylindrical upper portion of the reactor chamber, an outlet line for an oxygen-depleted gas stream 110 positioned at the top of the cylindrical upper portion;and a discharge conduit for a flow of oxygen-carrier particles 102 positioned at the bottom of the lower inverted truncated cone portion. ;

[0063] The reduced oxygen carrier 400 is advantageously mixed with an oxidizing gas stream 100, typically air or steam, and preferably air, in an inlet line of the cyclone oxidation reactor. The oxidizing gas stream is preferably delivered through a main injection line into the inlet line of the cyclone reactor, connected to the outlet of the cyclone 3002. The circulation line between the cyclone 3002 and the inlet line of the cyclone reactor preferably includes a gas-sealing device such as a siphon as shown in the figure 2 .

[0064] Air that can be used as an oxidizing gas is preferably composed of approximately 21% oxygen and 78% nitrogen (also commonly referred to as "fresh" air). The remaining 1% is composed mainly of argon, but also of other rare gases such as neon, krypton, and xenon, as well as approximately 0.04% carbon dioxide.

[0065] The gas mixture 120 containing the oxygen carrier 400 is then sent into the upper cylindrical portion of the cyclonic oxidation reactor chamber.

[0066] In the cyclonic oxidation reactor chamber, the oxygen carrier is oxidized upon contact with the oxidizing gas 100, and the oxidized oxygen carrier is separated from the oxygen-depleted oxidizing gas 110, i.e., depleted air, also called "depleted" or "depleted" air, resulting from the oxidation. The oxygen-depleted oxidizing gas 110 is discharged through the outlet pipe at the top of the upper cylindrical portion of the chamber, and a stream of oxidized oxygen carrier 102 is discharged through the outlet pipe at the bottom of the lower inverted frustoconical portion of the chamber. The stream of oxidized oxygen carrier particles 102 is transferred to the reduction reactor 2000. Advantageously, the 102 flow line includes a sealing device, for example, a siphon.

[0067] A depleted oxidizing gas (e.g., depleted air) is defined as an oxidizing gas depleted in oxygen compared to an initial oxidizing gas (e.g., initial air or "fresh" air) before the reaction in the oxidation zone. The depleted gas (e.g., depleted air) preferably contains less than 4% oxygen. The oxygen content of the depleted gas depends on the amount of oxygen initially present in the initial oxidizing gas (approximately 21% in the case of fresh air) and on the overstoichiometry applied to ensure the maximum oxidation state of all the oxygen carrier particles.

[0068] Typically, the depleted oxidizing gas (e.g., depleted air) contains approximately 2% oxygen. "Approximately" means within ±0.5%. This results from the preference for applying an overstoichiometry of around 10% to ensure sufficient oxidation of all particles. This overstoichiometry may be necessary to compensate for limitations in transfer between oxygen and particles and can vary depending on the reaction kinetics with the oxygen carrier and the hydrodynamics within the reactor.

[0069] The function of the cyclonic oxidation reactor 3200 to oxidize the oxygen carrier results in the enrichment of the latter in oxygen by reaction between the reduced form of the oxygen carrier and the dioxygen of the oxidizing gas 100.

[0070] In the cyclonic oxidation reactor 3200, the oxygen carrier is restored to its oxidized state MxOy upon contact with the oxidizing gas 100 (e.g., air or water vapor, and preferably air), according to reaction (2) below. [Math 2] MxOy - 2n - m / 2 + (n + m / 4) O2 → MxOy

[0071] Where n and m represent respectively the number of carbon and hydrogen atoms that have reacted with the oxygen carrier in the combustion reactor.

[0072] This reaction depends on the temperature, the partial pressure of oxygen, and also the contact time between the solid and the oxidizing gas. This time is generally between 1 and 30 seconds.

[0073] The residence time of the oxygen carrier in the oxidation reactor is less than or equal to 30 seconds, preferably between 1 s and 30 s, more preferably between 1 s and 20 s, even more preferably between 1 s and 10 s.

[0074] The temperature in the cyclonic oxidation reactor is generally between 600°C and 1400°C, preferably between 700°C and 1000°C.

[0075] The oxygen carrier, alternately passing from its oxidized form in the cyclonic oxidation reactor to its reduced form in the reduction reactor and vice versa, describes a redox cycle.

[0076] The oxygen carrier can be composed of metal oxides, such as for example oxides of Fe, Ti, Ni, Cu, Mn, Co, V, alone or in mixture, which can be derived from ores (for example ilmenite, hematite or pyrolusite) or be synthetic (for example copper oxide particles supported on alumina CuO / Al 2 O 3 or nickel oxide particles supported on alumina NiO / Al 2 O 3, preferably copper oxide particles supported on alumina CuO / Al 2 O 3), with or without a binder, and has the required redox properties and characteristics necessary for the implementation of fluidization.

[0077] Without being exhaustive, the oxygen carrier includes at least one metal oxide which may be included in the list consisting of the oxides of Fe, Cu, Ni, Mn and / or Co, a perovskite exhibiting redox properties (e.g. a perovskite of formula CaMnO3 or a perovskite combining Mn, Ti and Fe), a metallic aluminate spinel exhibiting redox properties, preferably a metallic aluminate spinel of formula CuAl2O4 or of formula CuFe2O4.

[0078] The oxygen storage capacity of the oxygen carrier is advantageously between 0.5% and 15% by weight, depending on the type of material. Advantageously, the amount of oxygen actually transferred by the metal oxide is between 0.5% and 3% by weight, which allows only a fraction of the total oxygen transfer capacity to be used, ideally less than 30%, in order to limit the risks of mechanical aging or particle agglomeration. Using only a fraction of the oxygen transport capacity also has the advantage that the fluidized bed acts as a thermal ballast, thus smoothing out temperature variations along the oxygen carrier's path.

[0079] The oxygen carrier is in the form of fluidizable particles belonging to groups A, B, C, or D of the Geldart classification, preferably to groups A, B, or D, alone or in combination. Preferably, the oxygen carrier particles belong to group B of the Geldart classification. By way of example, and without limitation, the group B particles used have a particle size distribution such that more than 90% of the particles are between 100 µm and 500 µm in size, preferably between 150 µm and 300 µm.

[0080] Preferably, the oxygen carrier particles, which can be metallic oxides, synthetic or natural minerals, supported or unsupported, have a density between 1000 kg / m³ and 5000 kg / m³ and preferably between 1200 kg / m³ and 4000 kg / m³.

[0081] For example, nickel oxide particles supported on alumina (NiO / NiAl₂O₃) generally have a grain density between 2500 kg / m³ and 3500 kg / m³, depending on the porosity of the support and the nickel oxide content, typically around 3200 kg / m³. Ilmenite, an ore combining titanium and iron (iron and titanium oxide: FeTiO₃), has a density of 4700 kg / m³.

[0082] The oxygen carrier can undergo an activation phase in order to increase its reactive capabilities, which may consist of a temperature rise phase, preferably gradual, and preferably under an oxidizing atmosphere (for example under air).

[0083] Preferably, the oxygen carrier has the property of oxidizing rapidly under the conditions operating in the cyclonic oxidation reactor, particularly the temperature conditions. Preferably, an oxidation rate of the oxygen carrier (i.e., the ratio of oxidized mass to active mass) of between 55% and 95% is reached in 30 seconds or less in the cyclonic oxidation reactor, preferably in 20 seconds or less, and more preferably in 10 seconds or less. Suitable oxygen carriers for such rapid oxidation, without being exhaustive, include, for example, perovskite particles (a perovskite exhibiting redox properties, for example, a perovskite combining Mn, Ti, and Fe), copper oxide particles supported on alumina, manganese ore, hematite, ilmenite, etc.According to one or more embodiments, the carrier used comprises particles of perovskite, copper oxide supported on alumina, or manganese ore.

[0084] The cyclonic structure of the oxidation reactor is preferably that of a conventional reverse-flow cyclone with a tangential inlet. In this type of cyclone, the gas mixture containing solid particles enters at the top and is subjected to centrifugal motion due to its tangential inlet. The particles are propelled towards the cyclone wall by centrifugal force and then fall down the wall due to gravity. At the bottom of the cyclone, in the inverted truncated cone section, the gas flow, now free of particles which are discharged to the bottom of the truncated cone section, reverses to form an internal vortex that exits through an axial duct at the top of the cyclone.In the cyclonic oxidation reactor according to the invention, the outlet conduit of the oxygen-depleted gas stream 110 is preferably arranged in the axis of the cylindrical-conical chamber of the reactor, and may include an internal cylindrical part over a height h, generally called a "vortex finder" in English, as is classic in a flow reversing cyclone.

[0085] The function of the cyclone oxidation reactor 3200 of separating the oxidized oxygen carrier from the oxygen-depleted oxidizing gas, while ensuring oxidation, is ensured by the cyclone structure of the reactor, and results in the production of the oxygen-depleted gas stream 110 exiting at the top of the upper cylindrical portion of the reactor chamber, and the oxygen carrier particle stream 102 being discharged at the bottom of the lower inverted truncated cone portion of the reactor chamber.

[0086] The gas / solid mixture entering the cyclone reactor undergoes a dizzying motion due to centrifugal force. This motion produces several spirals in the upper cylindrical section of the cylindro-conical chamber (also commonly called the "barrel" for a cyclone) before separation occurs between the gas exiting through the outlet pipe at the top of the chamber and the solid collected at the bottom. The number of spirals traversed by the gas / solid mixture in the cyclone reactor depends on the inlet and outlet velocities and the solid concentration in the gas. For the same gas inlet and outlet geometry, the separation efficiency of the cyclone reactor remains constant, while the solid residence time in the cyclone reactor can be adjusted as needed by designing a cyclone reactor with a larger diameter and height.A larger diameter of the cyclone reactor increases the perimeter traveled by the spiral of the solid and allows the desired residence time to be obtained to carry out the oxidation reaction.

[0087] Preferably, the inlet pipe of the cyclonic oxidation reactor can have a rectangular cross-section.

[0088] The inlet pipe of the cyclonic oxidation reactor may also be equipped with at least one secondary injection pipe for oxidizing gas 100 (not shown in the figure 2), preferably located on the lower wall of the inlet pipe. This secondary injection pipe(s) allow the injection of oxidizing gas in such a way as to disperse the solid particles of the oxygen carrier and limit the risk of solid particle deposition in the inlet pipe. Such a risk can also be limited by using an inlet pipe whose lower wall is inclined relative to the horizontal at an angle α greater than the angle of repose of the solid particles. The angle α preferably has an absolute value between α' and α'+45°, preferably between α'+10° and α'+20°, α' being the angle of repose of the particles. The angle of repose or slope α' of the particles is traditionally defined as the angle between the slope of the loose powder pile and the horizontal direction and can be determined by various methods.For example, this angle can be measured by pouring the powder through a funnel, which forms a small pile of product characterized by a slope relative to the horizontal surface. The angle of repose can also be measured by sliding a solid down an inclined plate, the angle of repose then being measured as the angle at which the solid material begins to slide, or by using a rotating cylinder to determine the angle at which the solid flows. These last two methods are preferably used to determine the angle of repose because they involve the movement of the solid. The angle α of inclination of the lower wall of the inlet pipe can have an absolute value between 5° and 80°, preferably between 15° and 60°, more preferably between 15° and 45°, and even more preferably between 20° and 45°.

[0089] The downward slope of the lower wall of the inlet pipe promotes the flow and re-acceleration of solid particles towards the cyclone reactor chamber, reducing the saltation velocity of the particles and consequently particle accumulation. Secondary injection pipes allow for the injection of oxidizing gas, supplementing the main injection, to disperse the solid particles. Specifically, this redirects any solid particles that fall onto the lower wall back into the main gas flow in the inlet pipe, and breaks up any particle agglomerates.For example, the flow rate of oxidizing gas supplied via the secondary injection lines is between 0.1% and 30% by volume of the oxidizing gas flow rate injected through the main injection line and used for oxygen carrier oxidation in the cyclone reactor, or even between 1% and 10% by volume. By minimizing the deposition of solid particles in the inlet pipe, the cyclone reactor inlet is prevented from clogging, thus avoiding disruption to the reactor's cyclonic operation and, consequently, to proper gas / solid separation. Disperding the solid particles in the main gas stream allows for the entrainment of a maximum number of particles into the cyclone oxidation reactor chamber, resulting in better gas / solid separation than if these same particles were to stagnate and agglomerate in the pipe.

[0090] The number of secondary injection ducts depends on the total flow rate of additional oxidizing gas injected, and the lower wall of the duct may have, for example, between 1 and 10, preferably between 2 and 5, secondary injection ducts per square meter.

[0091] The secondary injection duct(s) are preferably configured to form a jet with an angle between 0° and 90°, preferably greater than 0° and less than 90°, and more preferably between 0° (and preferably greater than 0°) and 45°, relative to the horizontal axis in a vertical plane. The resulting jet is thus preferably directed along the axis of the gas / solid mixture flow in the duct, so as not to unduly disrupt the flow towards the cyclone oxidation reactor chamber.

[0092] Advantageously, the secondary injection duct(s) can be configured so that the gas velocity at the outlet of said duct is between 5 m / s and 100 m / s, preferably between 20 m / s and 40 m / s, to prevent solid particles from entering the secondary injection duct, to obtain good dispersion of solid particles and break up any agglomerates without creating attrition.

[0093] Preferably, the inlet pipe may have a section at the inlet of the reactor chamber such that the surface velocity of the gas of the gas / gaseous solid mixture exiting said inlet pipe and entering the chamber is between 5 m / s and 35 m / s, and more preferably between 15 m / s and 25 m / s, to have good separation performance.

[0094] Advantageously, the cross-sectional areas of the inlet pipe at both ends can be equal, and consequently, the surface velocities of the gases attached to them can also be equal. In this way, it is possible to limit erosion of the cyclone reactor and particle attrition due to strong impacts with the cyclone walls, which could occur if the gas velocity increased. This is possible, for example, if the inlet pipe with its inclined lower wall also has a vertical side wall inclined at a defined angle β in the horizontal plane, so that the cross-sections at the ends have the same area, or even if the cross-sectional area along the entire length of the inlet pipe is constant. The angle β can have an absolute value between 5° and 70°, preferably between 10° and 50°.

[0095] According to the invention, the cyclonic oxidation reactor is operated under the temperature conditions of the CLC process as already detailed above. It is therefore preferably made of materials adapted to the high temperatures encountered in CLC, typically between 700°C and 1000°C, or even between 600°C and 1400°C, for example, and without limitation, high-temperature steels, such as those of the Hastelloy®, Incoloy®, Inconel® or Manaurite® type, or conventional steels, for example stainless steel or carbon steel combined with refractory materials or combined with cooling means such as tubes in which a heat transfer fluid circulates.

[0096] The cyclonic oxidation reactor is well suited for the gas / solid separation of gas / solid mixtures containing solid particles with an average particle diameter between 20 µm and 1000 µm. In particular, the cyclonic oxidation reactor is well suited for the gas / solid separation of gas / solid mixtures containing solid particles of the size described above for the oxygen carrier, with a particle size distribution such that more than 90% of the particles are between 100 µm and 500 µm in size, preferably between 150 µm and 300 µm.

[0097] The cyclonic oxidation reactor is well suited for the gas / solid separation of gas / solid mixtures with a solid particle load preferably between 0.1 and 50 wt / wt (weight of solid particles relative to the weight of gas).

[0098] According to one or more variants not shown, the CLC installation may include several cyclone oxidation reactors configured to operate in parallel, with the oxidation of the oxygen carrier being carried out in parallel in the different cyclone oxidation reactors. The CLC installation then includes means for distributing the oxygen carrier and supplying oxidizing gas to the different cyclone oxidation reactors, as well as means for collecting the oxidized oxygen carrier from the different oxidation reactors for return to the reduction reactor 2000. Such a design makes it possible to meet a constraint on a maximum equipment size or a space constraint for the on-site installation of the CLC installation.

[0099] The CLC installation according to the invention, and in particular the cyclonic oxidation reactor, makes it possible to reduce the residence time of the oxygen carrier in the "air" loop (sections where the oxygen carrier is in contact with the air) by half compared to a classic scheme of an air reactor associated with a cyclone, without any decrease in performance.

[0100] Furthermore, the CLC installation according to the invention is more compact compared to the classic CLC scheme as represented in the figure 1 , and capital expenditure (CAPEX) costs can be lower due to savings on equipment.

[0101] An advantage of the invention also lies in the possible transformation of existing industrial combustion units, typically comprising a boiler which can be converted into a fuel reactor and equipped with a cyclonic oxidation reactor as described to form a CLC installation.

[0102] In one or more variants not shown, the CLC installation comprises several cyclone oxidation reactors configured to operate in series. Examples are illustrated in figures 3 And 4 and described below.

[0103] There figure 3 represents a CLC installation according to one or more embodiments of the present invention, as well as its operation, comprising two successive cyclonic oxidation reactors. The CLC installation and its operation are identical in all respects to what has been described in relation to the figure 2 with the exception of the oxygen carrier oxidation section, which is detailed below. Nevertheless, the principle of oxygen carrier oxidation, the nature of the reactants, the temperature conditions, the structure of the cyclonic oxidation reactor, and the materials used for the reactors are identical to those described in relation to the figure 2 , and are not repeated here.

[0104] According to this or these embodiments, the CLC installation and process include a staged oxidation: the oxidation reaction of the oxygen carrier is broken down into n successive steps, for example into two steps each using a dedicated cyclone oxidation reactor, the two cyclone oxidation reactors operating in series, as shown in the figure 3 .

[0105] At each of these oxidation steps, the oxygen carrier is mixed with an oxidizing gas and carried along by a flow rate of oxidizing gas equivalent to 1 / n of the flow rate of oxidizing gas required for the complete oxidation of the oxygen carrier.

[0106] The reduced oxygen carrier stream 400 is introduced into the inlet pipe of a first cyclonic oxidation reactor 3201 where it is mixed with a first oxidizing gas stream 130, resulting in a first gas / solid mixture 131 which is introduced into the first cyclonic oxidation reactor 3201, operating in the same manner as described in relation to the figure 1except that the separated oxygen carrier discharged from said first reactor is partially oxidized and its oxidation is completed in a second cyclonic oxidation reactor 3202. From the operation of the first cyclonic oxidation reactor 3201, there results in a stream of depleted oxidizing gas 140 discharged through an outlet pipe at the top of the chamber of the first reactor 3201, and a stream of partially oxidized oxygen carrier 401 discharged through the outlet pipe of the first reactor 3201. The stream of partially oxidized oxygen carrier 401 is sent to the inlet pipe of the second cyclonic reactor 3202 where it is mixed with a second stream of oxidizing gas 150 to form a second gas-solid mixture 151 which is introduced into the second cyclonic oxidation reactor 3202.The oxidation of the carrier is then completed within the chamber of this second cyclonic oxidation reactor 3202, resulting in a second flow of depleted gas 160 discharged through an outlet pipe at the top of the chamber of the second reactor 3202, and a flow of oxidized oxygen carrier 102 discharged through the outlet pipe of the second reactor 3202, destined for the reduction reactor 2000.

[0107] The embodiment(s) represented in the figure 3 have the advantage of allowing oxidation of the oxygen carrier while meeting a constraint on a maximum equipment size to be respected or a space constraint for the on-site installation of the CLC installation.

[0108] There figure 4represents a CLC installation according to one or more embodiments of the present invention, as well as its operation, comprising two successive cyclonic oxidation reactors, the first of which is supplied with an oxygen-depleted oxidizing gas from the second oxidation reactor. The CLC installation and its operation are identical in all respects to what has been described in relation to the figure 2 with the exception of the oxygen carrier oxidation section, which is detailed below. Nevertheless, the principle of oxygen carrier oxidation, the nature of the reactants, the temperature conditions, the structure of the cyclonic oxidation reactor, and the materials used for the reactors are identical to those described in relation to the figure 2 , and are not repeated here.

[0109] According to this or these embodiments, the CLC installation and process include a staged oxidation as illustrated in the figure 3comprising n oxidation steps, except that the oxygen carrier in its most reduced state is brought into contact with an oxygen-depleted oxidizing gas from a downstream oxidation stage. The oxidation is also carried out here in n successive steps, for example in two steps each using a dedicated cyclonic oxidation reactor, the two cyclonic oxidation reactors operating in series, as shown in the figure 4 , but unlike the oxidation illustrated in the figure 3The oxygen-depleted gas stream from the second cyclone oxidation reactor serves as the oxidizing gas supplied to the main injection duct of the inlet pipe of the first cyclone reactor. If n is greater than 2, each stage is supplied with oxygen-depleted air from the downstream cyclone oxidation reactor. Only the last cyclone oxidation reactor is supplied with fresh air: the final percentage points of oxidation are the most difficult to achieve, and therefore fresh, oxygen-rich air is advantageously used in the most downstream reactor. At each of these oxidation stages, the oxygen carrier is mixed with an oxidizing gas and carried along by an oxidizing gas flow rate equivalent to 1 / n of the oxidizing gas flow rate required for the complete oxidation of the oxygen carrier.

[0110] According to this embodiment or these embodiments, the oxidizing gas flow rate required for complete oxidation preferably corresponds to the fresh air flow rate 150 in the last cyclonic oxidation reactor. Each cyclonic oxidation reactor (from the penultimate to the first) preferably receives a progressively decreasing flow rate of oxidizing gas, as it is progressively depleted in O2.

[0111] The reduced oxygen carrier stream 400 is introduced into the inlet pipe of a first cyclonic oxidation reactor 3301 where it is mixed with the gas stream 180 produced in a second cyclonic oxidation reactor 3302, resulting in a first gas / solid mixture 181 which is introduced into the first cyclonic oxidation reactor 3301, operating in the same manner as described in relation to the figure 1except that the separated oxygen carrier discharged from said first reactor is partially oxidized and its oxidation is completed in the second cyclonic oxidation reactor 3302. From the operation of the first cyclonic oxidation reactor 3301, there results in a stream of depleted oxidizing gas 190 discharged through an outlet pipe at the top of the chamber of the first reactor 3301, and a stream of partially oxidized oxygen carrier 401 discharged through the outlet pipe of the first reactor 3301. The stream of partially oxidized oxygen carrier 401 is sent to the inlet pipe of the second cyclonic reactor 3302 where it is mixed with a stream of fresh oxidizing gas 170 (e.g., fresh air) to form a second gas-solid mixture 171 which is introduced into the second cyclonic oxidation reactor 3302. The oxidation of the carrier is then completed within the chamber of this second cyclonic oxidation reactor 3302. from which two flows result: the gas flow 180 discharged through an outlet pipe at the top of the chamber of the second reactor 3202, said outlet pipe being connected to the inlet pipe of the first cyclonic oxidation reactor 3301 to form the main oxidizing gas injection pipe of the first inlet pipe, and the flow of oxidized oxygen carrier 102 discharged through the outlet pipe of the second reactor 3302, to the reduction reactor 2000.

[0112] The embodiment(s) represented in the figure 4These arrangements have the advantage of allowing oxidation of the oxygen carrier while meeting constraints on maximum equipment dimensions or space limitations for on-site installation of the CLC system. Another advantage of this scheme lies in the potential reduction of the contact time required for oxygen carrier oxidation: the oxygen carrier, in its most reduced state and therefore most "active" for oxidation, is brought into contact with the oxidizing gas that is least oxygen-rich. Consequently, the residence time required to reach a given oxidation state is shorter than for a co-current arrangement, such as those used in the state of the art or in the... figure 3 .

[0113] There figure 5represents a CLC installation according to one or more embodiments of the present invention, as well as its operation, well adapted to the combustion of a solid hydrocarbon feedstock, comprising a cyclonic oxidation reactor and a solid / solid separation device at the outlet of the reduction reactor.

[0114] In the case of solid fuel combustion, the CLC installation may indeed include: a solid / solid separator 3100, as already mentioned above, disposed downstream and connected directly, i.e. without any other enclosure or intermediate device, to the reduction reactor 2000, configured to operate in a fluidized bed, to receive a gas / solid mixture 301 from said reduction reactor 2000, and to perform the separation between particles of the reduced oxygen carrier 440 and unburned particles contained in the gas / solid mixture 310; and at least one cyclone 3002 disposed downstream of the solid / solid separation device 3100 and configured to receive a gas stream 601 comprising the unburned particles and to perform the separation between the unburned particles and the combustion fumes 610, the cyclone 3002 preferably comprising an outlet line for the unburned particles 602 connected to the reduction reactor 2000.

[0115] The oxygen carrier stream 102 is conveyed to the fluidized reduction reactor 2000 by a fluidizing gas 300, where it reacts with the solid hydrocarbon feedstock 201. The conversion of the hydrocarbons in a single pass may be incomplete and require multiple passes through the reduction reactor, with recycling of the unconverted fraction of the feedstock. The solid / solid separator 3100 separates the reduced oxygen carrier 440 from a gaseous stream 601 containing combustion gases, fluidizing gas, an unconverted solid fraction of the feedstock called unburned particles, and a minor fraction of oxygen carrier.The gas stream 601 containing solid particles is separated in the cyclone 3200 which evacuates a stream 610 containing the combustion fumes (and also containing part of the fluidization gas) and on the other hand a stream 602 containing the unconverted fraction of the charge (unburned particles) and a minor fraction of the oxygen carrier, which are preferably rerouted to the reduction reactor 2000.

[0116] The reduced oxygen carrier flow 440 is preferably extracted from the solid / solid separator 3100 by means of an L-valve 4000, which is a device for controlling the oxygen carrier flow through it according to the fraction of oxidizing gas 100, e.g., air, that is introduced into the vertical part of the L-valve. The remainder of the oxidizing gas, e.g., air, can be introduced into the horizontal part of the L-valve so as to form and transport the gas-solid mixture 115 to the cyclonic oxidation reactor 3400 where the oxygen carrier oxidation and gas / solid separation are carried out as described in relation to the figure 2 , and from which two flows result, a flow of depleted oxidizing gas 116, e.g. depleted air, and a flow of oxidized oxygen carrier 102 to the reduction reactor 2000.

[0117] Other cyclones similar to cyclone 3002 can be positioned downstream of cyclone 3002 for further gas / solid separation.

[0118] The 3100 solid / solid separator is used to separate unburned particles from oxygen carrier particles based on their different size and density properties. Indeed, the oxygen carrier particles, described above, generally have a much larger size and density than unburned particles, and also than fly ash from the reduction reactor. The 3100 solid / solid separator can therefore be used to separate unburned particles from oxygen carrier particles with a density greater than or equal to 1000 kg / m³, preferably greater than or equal to 1200 kg / m³, and more preferably greater than or equal to 2500 kg / m³.Typically, over 90% of the oxygen carrier particles are between 100 µm and 500 µm in size, preferably between 150 µm and 300 µm. At the outlet of the reduction reactor, the size of the unburned particles is estimated to be less than 100 µm, and the majority of these unburned particles are between 20 µm and 50 µm in size. The density of these unburned particles is generally between 1000 and 1500 kg / m³.

[0119] Other particles, such as fly ash (distinct from unburned fuel particles), resulting from the combustion of the solid fuel charge, can also circulate with the remaining particles. These particles are characterized by a smaller particle size and density than oxygen carrier particles (i.e., less than 100 µm) and are often smaller than unburned fuel particles as well. Ash consists of incombustible elements resulting from the complete combustion of solid fuel particles that have remained in the combustion reactor for a sufficient duration. Ash is primarily mineral in nature. It typically contains the following compounds: SiO₂, Al₂O₃, Fe₂O₃, CaO, MgO, TiO₂, K₂O, Na₂O, SO₃, and P₂O₅.If ash is present in the process and in particular in the gas mixture from the reduction reactor, it can be separated and carried with the unburned particles into the solid / solid separator 3100.

[0120] Such a solid / solid separator is known and, for example, described in international patent application WO2011151535. It preferably comprises a chamber with an inlet line for the gas / solid mixture 301 opening into a dilute phase at the top of the chamber, an outlet line at the bottom of the chamber, and a discharge line at the top of the chamber. The inlet and discharge / discharge parameters are chosen to create a dense phase at the bottom of the chamber and the dilute phase at the top (solid content generally less than 5%, or even 1%).In the solid-to-solid separator, the surface velocity of the gas flow is advantageously greater than the terminal settling velocity of the unburned particles to allow their entrainment with the gas, thus enabling a "rapid" separation between the heavy particles (oxygen carriers) and the light particles (unburned particles). Rapid separation is defined as a separation occurring in less than 1 minute and preferably in less than 20 seconds, this duration corresponding to the residence time of the light particles in the dilute phase of the separator.

[0121] While many features have been described in the various embodiments presented, it will be obvious to those skilled in the art that these features can be combined in any possible combination. For example, the embodiment(s) described in relation to the figure 5may include several cyclonic oxidation reactors as described in relation to the figures 3 And 4 . Example

[0122] The following example aims to illustrate some performance features of an example of a cyclone oxidation reactor of the CLC installation according to the invention, in particular the oxidation and separation that can be achieved in the cyclone oxidation reactor.

[0123] The exemplified cyclonic oxidation reactor is as described in relation to the figure 2 , and includes the main features given in Table 1 below. [Table 1] Cyclonic reactor diameter (barrel) meters 2,4 Inlet height (rectangular section of the incoming pipe) meters 1,4 Entrance width meters 0,6 Cyclonic reactor height (cylindro-conical chamber) meters 12 V out gas (m / s) m / s 35,0 Number of spirals - 5,2 Solid flow kg / s 65 Temperature of the solid at the inlet °C 830 Air flow rate at 21% mol O2 kg / s 5 Air temperature at the inlet °C 40 Solid residence time s 8,7

[0124] Such a cyclonic oxidation reactor allows, for example, the oxidation of oxygen carriers of the ilmenite type, manganese ore, iron ore, perovskite, copper oxide on alumina entering the reactor at an oxidation rate of 55% up to an oxidation rate greater than or equal to 90%, as indicated in Table 2 below. [Table 2] Oxidation rate at reactor outlet Ilmenite 90% Manganese ore 91% Perovskite with formula CaMn 0.375 Ti 0.5 Fe 0.125 O 3 100% Tierga iron ore (hematite) 95% CuO at 10 wt% on Al 2 O 3 100%

[0125] Such a cyclonic oxidation reactor also allows the separation of solid particles from the oxygen carrier and depleted air.

[0126] For particles of 250 microns (particle size between 160 and 475 microns) in average diameter and a density of 2500 kg / m 3< , a gas / solid separation of 100% is obtained, with an air flow rate of 5 kg / s and an inlet velocity of 20 m / s.

Claims

1. Chemical looping combustion plant for the combustion of a hydrocarbon feedstock using a solid-state oxygen carrier in the form of particles, comprising at least: - a reduction reactor (2000) configured to operate as a fluidized bed and perform the combustion of said hydrocarbon feedstock (200, 201) in contact with said oxygen carrier (102); - at least one cyclone oxidation reactor (3200, 3201, 3202, 3301, 3302, 3400) configured to oxidize said reduced oxygen carrier (400, 440) coming from said reduction reactor by bringing it into contact with an oxidizing gas (100, 130, 150, 180) and to separate said oxidized oxygen carrier from said oxygen-depleted oxidizing gas (110, 140, 160, 180, 190, 116); - lines for circulating said oxygen carrier between said reduction reactor (2000) and said at least one cyclone oxidation reactor (3200, 3201, 3202, 3301, 3302, 3400) .

2. Plant according to Claim 1, wherein said at least one cyclone oxidation reactor comprises: - a cylindrical-conical chamber comprising a cylindrical upper portion surmounting an inverted frustoconical lower portion; - an inlet pipe carrying a gaseous mixture containing particles of the oxygen carrier and oxidizing gas, said inlet pipe being equipped with a main injection duct for the injection of oxidizing gas (100, 130, 150, 180) and said inlet pipe opening into said cylindrical upper portion; - an outlet pipe for a stream of oxygen-depleted gas, this pipe being positioned at the top of the cylindrical upper portion; - a discharge pipe for discharging a stream of particles of oxygen carrier, this pipe being positioned at the bottom of the inverted frustoconical lower portion.

3. Plant according to either one of the preceding claims, comprising several cyclone oxidation reactors configured to operate in series and / or in parallel.

4. Plant according to Claim 3, comprising two cyclone oxidation reactors (3201, 3202, 3301, 3302) configured to operate in series.

5. Plant according to Claim 3, comprising at least two cyclone oxidation reactors configured to operate in series, and wherein the outlet pipe of a second cyclone oxidation reactor (3302) positioned downstream of a first cyclone oxidation reactor (3301) is connected to the inlet pipe of said first cyclone oxidation reactor (3301) to form the main injection duct for the injection of oxidizing gas (180) fed to said first cyclone oxidation reactor (3301).

6. Plant according to any one of the preceding claims, wherein the inlet pipe of said at least one cyclone oxidation reactor is equipped with at least one secondary oxidizing-gas injection duct, preferably situated on a lower wall of said inlet pipe.

7. Plant according to any one of the preceding claims, comprising a cyclone (3002) positioned downstream of and connected directly to said reduction reactor (2000), configured to receive a gas / solid mixture (301) coming from said reduction reactor (2000) and to perform separation between the reduced oxygen carrier (400) and combustion flue gases (310), said cyclone (3002) comprising an outlet pipe for the reduced oxygen carrier (400), this pipe being connected to said at least one cyclone oxidation reactor (3200, 3201, 3301).

8. Plant according to any one of Claims 1 to 6, comprising: - a solid / solid separation device (3100) positioned downstream of and connected directly to said reduction reactor (2000), said solid / solid separation device (3100) being configured to operate as a fluidized bed, to receive a gas / solid mixture (301) coming from said reduction reactor (2000), and to perform separation between the particles of the reduced oxygen carrier (440) and unburnt particles contained in said gas / solid mixture, and - at least one cyclone (3002) positioned downstream of said solid / solid separation device (3100) and configured to receive a stream of gas (601) containing said unburnt particles and to perform separation between said unburnt particles and combustion flue gases (610), said cyclone (3002) preferably comprising an outlet pipe for said unburnt particles, which pipe is connected to said reduction reactor (2000).

9. Chemical looping combustion method for the combustion of a hydrocarbon feedstock using a solid-state oxygen carrier in the form of particles, wherein: - the hydrocarbon feedstock is burnt by bringing it into contact with the oxygen carrier in a reduction reactor (2000) operating as a fluidized bed; - the oxygen carrier that has passed through the reduction reactor (2000) is oxidized by bringing it into contact with an oxidizing gas (100, 130, 150, 180), preferably air, in at least one cyclone oxidation reactor (3200, 3201, 3202, 3301, 3302, 3400), and said oxidized oxygen carrier and the oxygen-depleted oxidizing gas are separated in said cyclone oxidation reactor before said oxidized oxygen carrier is returned to the reduction reactor (2000).

10. Method according to Claim 9, wherein: - an oxidizing gas (100) and the oxygen carrier (400, 440) coming from the reduction reactor (2000) are mixed in an inlet pipe of said at least one cyclone oxidation reactor; - said gaseous mixture (120, 131, 181, 115) containing the oxygen carrier is sent into a cylindrical upper portion of a cylindrical-conical chamber of said cyclone oxidation reactor, said cylindrical-conical chamber comprising the cylindrical upper portion surmounting an inverted frustoconical lower portion; - said oxygen carrier is oxidized in contact with the oxidizing gas and the oxidized oxygen carrier and the oxygen-depleted oxidizing gas are separated within said cylindrical-conical chamber; - said oxygen-depleted oxidizing gas (110, 140, 190, 116) is discharged via an outlet pipe positioned at the top of the cylindrical upper portion; - and a stream of oxidized oxygen carrier (102, 401) is discharged via a discharge pipe positioned at the bottom of the inverted frustoconical lower portion.

11. Method according to Claim 10, wherein the oxygen carrier (400, 440) coming from the reduction reactor (2000) is oxidized in two cyclone oxidation reactors (3201, 3202, 3301, 3302) operating in series and / or in parallel.

12. Method according to Claim 11, wherein the oxygen-depleted oxidizing gas discharged via the outlet duct of a second cyclone oxidation reactor (3302) positioned downstream of a first cyclone oxidation reactor (3301) is used to form the gaseous mixture in the inlet pipe of said first cyclone oxidation reactor (3301) and to oxidize the oxygen carrier (400, 440) coming from the reduction reactor (2000) within said first cyclone oxidation reactor (3301).

13. Method according to any one of Claims 9 to 12, wherein a gas / solid mixture (301, 601) coming from the reduction reactor (2000) is sent to a cyclone (3002) positioned downstream of and connected directly to said reduction reactor (2000) in order to separate the reduced oxygen carrier (400) from the combustion flue gases (310) contained in said gas / solid mixture, and the reduced oxygen carrier (400) is sent to said at least one cyclone oxidation reactor (3200, 3201, 3301).

14. Method according to any one of Claims 9 to 12, wherein the hydrocarbon feedstock is a solid feedstock in the form of particles (201), preferably selected from the list consisting of coal, coke, petcoke, biomass, oil sands and household waste, and wherein: - a gas / solid mixture (301) coming from the reduction reactor (2000) is sent to a solid / solid separation device (3100) connected directly to said reduction reactor (2000) and operating as a fluidized bed in order to separate the reduced oxygen carrier (440) from the unburnt particles contained in said gas / solid mixture; - a stream of gas (601) coming from the solid / solid separator and containing said unburnt particles is sent to at least one cyclone (3002) in order to separate said unburnt particles (602) from the combustion flue gases (610); - the reduced oxygen carrier (440) is sent to said at least one cyclone oxidation reactor (3400), preferably by means of an L-ported valve (4000); - optionally, said unburnt particles (602) are sent to said reduction reactor (2000).

15. Method according to any one of Claims 9 to 14, wherein the residence time of the oxygen carrier in said at least one oxidation reactor is less than or equal to 30 seconds.