semi-continuous gravity-flow granular carbonation reactor and carbonation process employing said reactor

Abstract

The present invention relates to a semi-continuous gravity-flow granular carbonation reactor, the use of the reactor for the carbonation of a granular solid material, and a process for carbonating a granular solid material using said reactor. Figure to be published: Figure 1

Description

Title of the invention: Semi-continuous gravity-flow granular carbonation reactor and carbonation process employing said reactor

[0001] The present invention relates to a semi-continuous gravity flow granular carbonation reactor, to the use of the reactor for the carbonation of a granular solid material, and to a process for carbonating a granular solid material using said reactor.

[0002] The increase in the flow of concrete waste, linked in particular to the large number of old buildings reaching the end of their lifespan, such as those built in the 1950s, as well as the rising costs of landfill disposal, has led several manufacturers to consider the recovery of demolition concrete. Indeed, demolition concrete waste now represents more than 19 million tons per year in France. Furthermore, the natural resources used to produce concrete (limestone, clay, etc.) are generally located in quarries that are sometimes too far from cities, which complicates their transport, and opening new quarries can involve lengthy and complex processes.

[0003] Carbonation of concrete occurs naturally in contact with the concrete and the atmosphere (with an atmospheric CO2 content of around 400 ppm).

[0004] The main reaction implemented can be represented by the following equation 1: Ca(OH)2 + CO2 + H2O -> CaCO3 + 2 H2O (Equation 1). In equation 1, calcium hydroxide reacts with CO2 to produce calcium carbonate and water. This is an exothermic reaction. This reaction can take time, given that it is a natural process.

[0005] Several studies have therefore been carried out to accelerate the carbonate of alkali or alkaline-earth materials such as concrete waste in order to produce recycled carbonated concretes which can be reused to produce new concretes and also to trap large quantities of CO2.

[0006] In particular, US patent application 2023 / 227356 describes a system for processing concrete granules for subsequent recycling comprising: a) a container at least partially gas-tight with i) at least one opening configured for at least one of the operations of filling and extracting concrete granules, and ii) an inlet configured to supply a gas including CO2 into the container, wherein the inlet is fluidly connected to a storage tank via a supply line; b) an inlet valve configured to control the flow rate of the supplied volume of gas into the container; c) at least one sensor configured to determine a measure of CO2 absorption by the concrete aggregate in the container; and d) a control unit operationally connected to at least one sensor and the inlet valve and configured to control the volumetric flow rate supplied via the inlet valve. The associated method consists of filling said container with concrete aggregate, supplying the system with gas including CO2, determining whether a predefined CO2 saturation of the concrete aggregate has been reached by measuring the CO2 absorption of the concrete aggregate using at least one sensor; if the predefined CO2 saturation of the concrete aggregate has been reached, removing the CO2-enriched concrete aggregate.In particular, saturation is considered to be reached when the pressure and / or CO2 concentration within the container no longer varies. This solution has several drawbacks. Firstly, the system operates in batch mode. The carbonation of the aggregates is therefore carried out batch by batch, which limits the quantity of aggregates that can be treated. Secondly, the kinetics of CaCO3 formation follow an increasing profile over time, reaching an asymptote. Thus, the CO2 consumption rate in a batch reactor is variable, very high at the beginning of the reaction and decreasing progressively. This type of system is therefore particularly poorly suited to the use of a constant CO2 flow. Furthermore, at the end of the reaction, the reactor volume remains occupied despite very low CO2 consumption.Finally, CO2 access to the aggregates is not optimized, leading to carbonation heterogeneity within a batch or excessively long carbonation times. Consequently, the residence time of the aggregates and / or their contact with CO2 are not optimized.

[0007] Other reactors are known to implement carbonation in a liquid medium. They therefore require drying steps and consequently a longer treatment time and significant associated costs.

[0008] Other reactors are known to perform carbonation in a fluidized bed, possibly with recirculation. These solutions involve very high energy costs when the particle sizes of the materials exceed 1 mm.

[0009] Other reactors use direct CO2 flows (known as open-cycle). These solutions offer advantages in terms of implementation costs, but with significant CO2 losses. The term carbon efficiency refers to the percentage of CO2 actually captured relative to the amount of CO2 supplied. It is low for this type of open-cycle solution.

[0010] Thus, the state-of-the-art solutions for achieving the carbonation of carbonatable materials, with a particle size between 0 and 20 mm, from a constant CO2-rich gas flow, present the following disadvantages: - Batch reactors are poorly suited to constant gas flow and they do not optimize residence time or the interaction of CO2 with the material; - Continuous processes using a liquid or slurry route require additional costs to dry the finished product; - Continuous fluidized bed processes are not applicable to medium particle sizes (typically greater than 2 mm); - Continuous open-cycle processes have very low carbon yields; - In general, for batch-type reactors, the means to be implemented to drain the air-rich gas mixture after the introduction of the material, and especially to avoid CO2 losses, are not specified; and - In general, for continuous type reactors, the quantification and reduction of gas leaks at the inlet and outlet of the material are not specified.

[0011] Furthermore, there are no solutions that combine the following characteristics: - a continuous or semi-continuous carbonation process; - suitable for a particle size of 0 to 20mm, i.e. dealing with a granular flow, and without dissolving the material in a predominantly liquid phase; - reducing CO2 leaks and maximizing carbon yield; - maximizing the CO2 diffusion phenomena within the granular material and within individual grains.

[0012] Consequently, there is a need for new reactor architectures for the carbonation of recycled concrete aggregates or any type of granular solid material containing alkali or alkaline earth metals that can be implemented industrially with the processing of large quantities of solid aggregates, while maximizing the amount of CO2 trapped within said solid aggregates. There is also a need for carbonation reactors that optimize carbon yield, reduce gas leakage at the aggregate inlet and / or outlet, and / or reduce production costs.

[0013] It is specified that in the rest of the document, the terms first, second, third, fourth or even fifth do not necessarily imply the presence of all these elements but are used to number the different elements such as for example the closing mechanisms according to the different embodiments.

[0014] Reactor

[0015] The invention relates first to a carbonation reactor comprising: - a reactor body equipped with at least one CO2 gas injection device configured to inject said gas into the reactor body and / or at least one CO2 gas diffusion device configured to diffuse said gas into the reactor body, - a system for feeding the reactor body with granular solid material, and - a system for extracting a carbonated granular solid material from the reactor body, characterized in that: * The power supply system includes: - a first buffer volume configured to receive said granular solid material, - an inlet configured to supply said first buffer volume with said granular solid material, and - a first conveying device for said granular solid material from the first buffer volume to the reactor body, and * The extraction system includes: - a second buffer volume configured to receive said solid granular carbonate material, - a second conveying device for the granular carbonate solid material from the reactor body to said second buffer volume, and - an outlet configured to extract said solid granular carbonate material from said second buffer volume, and in that the feeding system and / or the extraction system, and in particular the first and / or the second conveying unit, are configured to move said solid granular material into the reactor body by gravity flow.

[0016] The reactor of the invention can be implemented on an industrial scale for processing large quantities of solid aggregates, while maximizing the amount of CO2 trapped within said solid aggregates. It makes it possible to optimize carbon yield, reduce gas leaks at the inlet and / or outlet of the aggregates, and / or reduce production costs.

[0017] In the invention, the carbon yield (in %) indicates the amount of CO2 actually trapped by the granular solid material relative to the amount of CO2 made available.

[0018] In the invention, the trapping rate (also well known by the anglicism "uptake", in kg of CO2 per kg of material) refers to the amount of CO2 trapped per quantity of granular solid material introduced.

[0019] Ideally, the highest carbon yield is sought, with the highest trapping rate and the highest production rate.

[0020] In general, the reactor and carbonation process of the invention, from a CO2 sequestration perspective, aim to distinguish themselves from the prior art by the following advantages: maximization of the amount of CO2 trapped, maximization of carbon yield and reduction of leakage, and cost reduction. The reactor and carbonation process are specifically designed to adapt to the input materials, and more particularly to their particle size and / or residual water content. Maximizing the amount of CO2 trapped depends, in particular, on the CO2 level in the reactor atmosphere; the higher the CO2 level, the higher the trapping rate and the reaction kinetics. This CO2 level is not solely related to the amount of CO2 injected into the reactor, but also depends on air infiltration and / or CO2 losses. If the material is dry and the finished product is used dry, it is highly desirable not to dissolve it in water.If the material has a specific particle size, fluidizing it is not always feasible because it would result in high energy expenditure. Furthermore, if the available CO2 flow rate is constant, a batch reactor is poorly suited because its consumption will vary due to the reaction conditions.

[0021] The granular solid material is in the form of powder (particle size < 1 mm) and / or granules (particle size > 1 mm), and preferably in the form of granules.

[0022] Consequently, the reactor of the invention differs from prior art reactors that use a slurry as the feed to be treated. Such a slurry is obtained after the addition of water and therefore contains a fairly large quantity of water (e.g., a liquid / solid mass ratio of approximately 1:1). The major drawback of such processes lies in the drying requirements associated with the finished product.

[0023] According to one embodiment, the granular solid material has a particle size of at most approximately 60 mm, preferably at most approximately 40 mm, particularly preferably at most approximately 20 mm, and particularly preferably at most approximately 10 mm. This particle size allows for better flow, increased reaction kinetics at the time of CO2 injection, as well as better inerting, limiting CO2 rise and therefore CO2 losses.

[0024] The first and second conveying elements are dimensioned for such a particle size.

[0025] The granular solid material may be chosen from recycled concrete aggregates, ashes such as combustion ash, industrial slags, by-products of industrial or mining activities, natural rocks containing alkali or alkaline earth metals, and any type of material likely to react with CO2 to form a chemically stable substrate via a thermodynamically favoured reaction (i.e. without external energy input).

[0026] According to one embodiment, the gas comprises at least 50% by mole, preferably at least 90% by mole, and particularly preferably at least 95% by mole of CO2, relative to the total number of moles of gas. This makes it possible to maximize the CO2 concentration in the reactor and to promote the kinetics of CO2 sequestration within the granular solid material.

[0027] The feeding and extraction systems are configured to allow a gravity flow, preferably semi-continuous, of the granular solid material within the reactor body. In other words, the granular solid material moves by gravity flow, preferably semi-continuous, within the reactor body thanks to the presence of the feeding system upstream of the reactor body and the extraction system downstream of the reactor body.

[0028] In particular, the first and / or second conveying elements are configured to move said solid granular material within the reactor body by gravity flow, and preferably by semi-continuous gravity flow. In other words, the granular solid material moves by gravity flow, preferably semi-continuous, within the reactor body thanks to the presence of the first and / or second conveying element. A multitude of rapid sequences can be considered a semi-continuous event.

[0029] In the invention, a semi-continuous regime or event means that the introduction of materials 1) from the outside into the first buffer volume, and 2) from the second buffer volume outwards is sequential, but that within the reactor body, the flow of the material is regular and smooth, similar to a continuous flow. Thus, a flow of granular solid material moves within the reactor body.

[0030] A regular (or semi-continuous) flow of the material in the reactor is thus obtained.

[0031] In the feeding system, the material is added while limiting air ingress and CO2 losses. The feeding system operates in a batch fashion. The reactor body is gradually fed with material according to the reaction kinetics, via the feeding system and, in particular, the shut-off devices as described below. At the bottom of the reactor body, the post-carbonation extraction system extracts the carbonated material via the second conveying device and sends it to the second buffer volume. The extraction system also operates in a batch fashion. The feeding and extraction systems, which operate in a batch fashion, are not the site of the carbonation reaction. The introduction of CO2 and The carbonation reaction takes place within the reactor body, where there is a semi-continuous flow of material. The amount of CO2 consumed is therefore constant within the reactor body. Furthermore, the granular solid material entering the reactor body is not carbonated. At the outlet of the reactor body, this granular solid material is carbonated. For a given distance traveled, all the materials are at the same degree of carbonation. Thus, the reactor body behaves like a plug flow reactor, maximizing the use of the available volume.

[0032] Power supply system

[0033] In one embodiment, the fuel system is partially gas-tight. This has the effect of limiting CO2 losses from the reactor to the ambient air, as well as air ingress into the reactor. The concept of "partially gas-tight" takes into account possible but undesired leaks, as well as the open / closed nature of the system. When the fuel system inlet is open, the system is not gas-tight, but it becomes so (with the exception of leaks) when the inlet is closed.

[0034] The feeding system is configured to introduce a granular solid material to be carbonated into the reactor body.

[0035] First buffer volume

[0036] The buffer volume configured to receive said granular solid material to be carbonated.

[0037] The first buffer volume of the feeding system supplies the reactor body with granular solid material for a predetermined period. Any residual CO2 present in the atmosphere of this first buffer volume can react with the granular solid material within it, thereby reducing CO2 losses to the outside. The reactor does not employ any means to inject and / or diffuse CO2 into the first buffer volume.

[0038] The feeding system, and in particular the first buffer volume, is thus equipped with an inlet designed to allow a sequenced feeding or distribution of granular solid material to the first buffer volume. This reduces air infiltration into the reactor.

[0039] The feed system inlet is configured to introduce the granular solid material to be carbonated into said first buffer volume.

[0040] The first buffer volume may include an outlet configured to supply granular solid material to the reactor body via the first conveying member.

[0041] According to one embodiment, the feeding system operates or is controlled so as to control the level of granular solid material in the reactor body.

[0042] The feeding system is preferably controlled, firstly, according to the level of material in the reactor body, and secondly, according to the pressure and / or pressure variation over time in the reactor body and / or the pressure difference between a point at the inlet and a point at the outlet of the reactor. This makes it possible to adapt the gravity flow velocity of the granular solid material within the reactor body.

[0043] Measuring elements

[0044] The feeding system may include a measuring device for the level of granular solid material.

[0045] The level measuring device of the feeding system is preferably located within the first buffer volume. Thus, the first buffer volume is preferably equipped with said level measuring device for the granular solid material.

[0046] The first buffer volume can be equipped with a device for measuring CO2 pressure and / or temperature and / or CO2 concentration and / or humidity. This configuration allows for a mass balance calculation, if necessary between two time points, and the deduction of the CO2 loss in the first buffer volume. In particular, this allows for estimating the quantity of CO2 before and after each opening to the outside.

[0047] The reactor preferably includes one or more and preferably several closing devices configured to isolate the feed system or part of the feed system from the reactor body and / or configured to isolate the extraction system or part of the extraction system from the reactor body, in particular when in operation.

[0048] First closing element

[0049] The feeding system preferably includes an actuable closure device configured to isolate the first buffer volume from the outside (i.e., from ambient air) (hereinafter referred to as the first closure device). This makes it possible to limit the inflow of ambient air into the first buffer volume and to the reactor body, while ensuring easy access for refilling said first buffer volume with granular solid material.

[0050] The first closing member is preferably positioned at the level of the inlet of the supply system, in particular to close said inlet.

[0051] The feeding system preferably includes means for controlling the first closing device to close the inlet of the feeding system when conveying said granular solid material from the first buffer volume to the reactor body and / or to open the inlet of the feeding system and refill the first buffer volume.

[0052] According to a particularly preferred embodiment, the first closing element is gas-tight.

[0053] In one embodiment, the first shut-off device of the feed system is a guillotine valve, a butterfly valve, or a ball valve. This helps to limit gas losses, particularly when the material contains particles with a particle size greater than approximately 1 mm.

[0054] In one embodiment, the first closing element of the feeding system is a rotary valve. This helps to limit gas losses, particularly when the material comprises particles with a particle size of approximately 1 mm or less (i.e., powdered material).

[0055] In one embodiment, the first closing member of the feeding system is in the open position to allow the introduction of new granular solid material at the optimal time, and in particular when the granular solid material present in the reactor body is at a low level (i.e. when the material level is lower than the position of a level measuring member of the reactor body as defined below).

[0056] First conveying element

[0057] The first conveying element is configured to move said granular solid material to be carbonated from the first buffer volume to the reactor body. The movement can be gravity-driven or non-gravity-driven.

[0058] The first conveying element for said granular solid material is preferably gas-tight.

[0059] The first conveying element is preferably an elongated element.

[0060] The first conveying element can be a tube, a cone, a non-motorized pipe, or a screw conveyor.

[0061] In a first embodiment, the first conveying element for the granular solid material from the first buffer volume to the reactor body is a screw conveyor. This embodiment is particularly suitable when the first conveying element transports the granular solid material to the reactor body in a direction perpendicular or not parallel to a direction of (gravitational) movement of the granular solid material within the reactor body.

[0062] According to this first embodiment, the first conveying element of the granular solid material from the first buffer volume to the reactor body is preferably motorized.

[0063] In a second embodiment, the first conveying element is a non-motorized tube, cone, or pipe. The granular solid material then flows by gravity from the first buffer volume to the reactor body. This embodiment is particularly suitable when the first conveying element transports the granular solid material to the reactor body in a direction parallel to the (gravitational) direction of movement of the granular solid material within the reactor body.

[0064] The presence of carbonatable granular solid material in the first conveying member makes it possible to reduce the escape of CO2 towards the inlet of the feed system, in particular by creating a local pressure loss.

[0065] Second and third closing elements

[0066] The feeding system may further include an actuable closing device configured to block access of the granular solid material (from the first buffer volume) to the first conveying device (hereafter referred to as the second closing device).

[0067] Said second closing device is preferably positioned at an outlet of the first buffer volume, in particular upstream of the first conveying device.

[0068] Said second closing element is preferably gas-tight.

[0069] The second closing device is preferably configured to connect the first buffer volume to the first conveying device.

[0070] Said second closing device is preferably of a similar design to the first closing device (i.e., a valve or airlock depending on the particle size of the material). This makes it possible to further reduce CO2 losses to the atmosphere and to limit air ingress into the reactor body.

[0071] The feeding system preferably includes means for controlling the second closing device to close the outlet of the first buffer volume when moving said granular solid material from the first conveying device to the reactor body and / or to open the outlet of the first buffer volume and reload the first conveying device.

[0072] Such a second closing device is particularly suitable when the first conveying device is a screw conveyor (non-gravity flow in said first conveying device).

[0073] The feeding system may include an actuable closing device configured to block access of the granular solid material (from the first conveying device) to the reactor body (hereinafter referred to as the third closing device).

[0074] Said third closing device is preferably positioned at an outlet of the first conveying device, in particular upstream of the reactor body.

[0075] Said third closing element is preferably gas-tight.

[0076] The third closing member is preferably configured to connect the first conveying member to the reactor body.

[0077] Said third closing device is preferably of a similar design to the first closing device (i.e., a valve or sluice gate depending on the particle size of the material). This makes it possible to further reduce CO2 losses to the atmosphere.

[0078] The feeding system preferably includes means for controlling the third closing device to close the outlet of the first conveying device and isolate the reactor body and / or to open the outlet of the first conveying device and reload it with material.

[0079] Such a third closing member is particularly suitable when the first conveying member is a tube or pipe (gravity flow in said first conveying member).

[0080] The first conveying member and / or the second closing member and / or the third closing member can be controlled, on the one hand according to the level of material in the body of the reactor, and on the other hand according to the pressure in the body of the reactor.

[0081] In particular, the second closing device and / or the third closing device opens when the first closing device is closed and when the reactor body has a pressure close to ambient pressure (i.e. close to 1.01325 bar or 1 atm). These characteristics help to limit the loss of CO2 to the outside of the reactor and to limit air ingress into the reactor.

[0082] Extraction system

[0083] The extraction system is configured to extract the granular carbonate solid material from the reactor body.

[0084] In one embodiment, the extraction system is partially gas-tight.

[0085] According to one embodiment, the extraction system operates or is controlled so as to control the level of granular solid material in the reactor body.

[0086] The extraction system is preferably controlled, firstly according to the level of material in the reactor body, and secondly according to the gas pressure in the reactor body. This makes it possible to adapt the gravity flow velocity of the granular solid material within the reactor body.

[0087] Measuring elements

[0088] According to one embodiment, the extraction system includes a measuring device for the level of solid granular carbonate material.

[0089] The level measuring device of the extraction system is preferably located within the second buffer volume. Thus, the second buffer volume is preferably equipped with said level measuring device for the granular carbonate solid material.

[0090] The second buffer volume can be equipped with a CO2 pressure measuring device and / or a temperature measuring device and / or a humidity measuring device and / or a CO2 concentration measuring device. This configuration allows for a mass balance calculation, if necessary between two points in time, and the deduction of the CO2 loss in the second buffer volume. In particular, this allows for estimating the quantity of CO2 before and after each opening to the outside.

[0091] Fourth closing element

[0092] The extraction system may further include an actuable closure device configured to block access of the solid granular carbonate material (from the second conveying device) to the second buffer volume (hereafter referred to as the fourth closure device).

[0093] Said fourth closing member is preferably positioned at an inlet of the second buffer volume, in particular downstream of the second conveying member.

[0094] Said fourth closing element is preferably gas-tight.

[0095] The fourth closing member is preferably configured to connect the second conveying member to the second buffer volume.

[0096] Said fourth closing member is preferably positioned at the outlet of said second conveying member. This avoids operation under load and facilitates the opening and closing of said fourth closing member.

[0097] Said fourth closing element is preferably of a similar design to the first closing element (i.e., a valve or airlock depending on the particle size of the material). This makes it possible to further reduce CO2 losses to the atmosphere and air intake.

[0098] The extraction system preferably includes means for controlling the fourth closing device to close the inlet of the second buffer volume and isolate the second conveying device and the reactor body and / or to open the inlet of the second buffer volume and discharge the carbonated material into the second buffer volume.

[0099] Second conveying element

[0100] The second conveying element is configured to move said granular carbonate solid material from the reactor body to said second buffer volume. The movement is preferably non-gravity.

[0101] In one embodiment, the second conveying element for the carbonated granular solid material to the second buffer volume is a screw conveyor. This embodiment is particularly suitable when the second conveying element transports the carbonated granular solid material to the second buffer volume in a direction perpendicular or not parallel to a (gravitational) direction of movement of the granular solid material in the reactor body.

[0102] The second conveying element for said solid granular carbonate material is preferably motorized.

[0103] The second conveying element for said solid granular carbonate material is preferably gas-tight.

[0104] The second conveying member may include an outlet configured to extract said solid granular carbonate material from said conveying member to the second buffer volume.

[0105] Fifth closing element

[0106] The extraction system preferably includes an actuable closure device configured to isolate the second buffer volume from the outside, and preferably to isolate the reactor body from ambient air that may enter the second buffer volume from the outside (during the release of the material to the outside) (hereinafter referred to as the fifth closure device). This prevents air ingress and / or CO2 losses during the conveying of the granular solid material from the reactor body to the second buffer volume.

[0107] The extraction system preferably includes means for controlling the fifth closing member to close the outlet of the extraction system during the conveying of said solid granular carbonated material from the reactor body to the second buffer volume and / or to open the outlet of the extraction system and discharge the carbonated material from the second buffer volume.

[0108] According to a particularly preferred embodiment, the fifth closing element is gas-tight.

[0109] Said fifth closing element is preferably of a similar design to the first closing element (i.e., a valve or a sluice gate depending on the particle size of the material). This makes it possible to further reduce CO2 losses to the atmosphere.

[0110] The fifth closing device is closed during operation and opens when it is desired to release the material present in the second buffer volume. In this case, the second conveying device is stopped, and the fourth closing device is also closed.

[0111] The second conveying element and / or the fourth closing element and / or the fifth closing element can be controlled, on the one hand, according to the level of material in the reactor body, and on the other hand, according to the pressure in the reactor body and / or the pressure variation over time in the reactor body and / or the pressure difference between a point at the inlet and a point at the outlet of the reactor. The presence of granular carbonate solid material in the second conveying element reduces the CO2 escape towards the outlet of the extraction system by consuming the residual CO2 present.

[0112] Gas extraction device

[0113] The reactor may further include a gas extraction device, preferably controllable, positioned in an upper part of the second buffer volume. This makes it possible to extract any CO2 that may have entered the second buffer volume with the material. This allows it to be recycled (reinjected into the reactor body and / or released to the outside).

[0114] Such an extraction device may be a vacuum system or a vacuum suction system.

[0115] In a preferred embodiment, the second buffer volume includes a vacuum system as a gas extraction device. This system removes the CO2-containing gas before it comes into contact with ambient air, with the first and second closure devices of the extraction system closed. Depending on the measured CO2 concentration, the vacuum system directs the gas to the reactor's CO2-containing gas supply system or to the injection devices if the CO2 level is deemed high; or to the outside if the CO2 level is deemed low.

[0116] In one embodiment, the reactor further comprises a separation system for separating a gas stream extracted from the second buffer volume and / or the reactor body into two fractions: a fraction enriched in CO2 and a fraction depleted in CO2. This allows for the recirculation of a more concentrated CO2 stream and improves carbonation performance.

[0117] In a preferred embodiment, the system for separating CO2 from other gases is of the membrane type, and it is preferably located upstream of the extraction system.

[0118] In one embodiment, the second buffer volume includes a repressurization system for connecting the second buffer volume to ambient air and / or the reactor body. This allows pressures to be equalized either between the outside and the second buffer volume before the fourth closing device is opened, or between the reactor body and the second buffer volume. before the opening of the fourth closing mechanism. This facilitates the proper functioning of the closing mechanisms and limits CO2 losses.

[0119] The reactor may further include a vacuum device connected: - to the suction, to the gas extraction devices located in the upper part of the reactor body, and / or located within the second buffer volume, and - to the discharge, outside or to the gas injection devices in the reactor body, where appropriate via a CO2 separation system.

[0120] Reactor body

[0121] The reactor of the invention has the advantage of operating in semi-continuous mode. More specifically, the reactor is configured to convey the aggregates of solid material, i.e., to circulate them progressively within the reactor body. This thus allows for semi-continuous gravity flow within the reactor body.

[0122] Such a reactor is therefore distinct from batch reactors, which are filled with carbonatable materials (e.g., concrete waste), and then CO2 is injected. At the end of the reaction, the materials are extracted from the reactor. This type of reactor has several drawbacks: firstly, the CO2 consumption rate is variable and increasingly lower. Indeed, as mentioned above, the formation of CaCO3 follows an increasing profile over time, reaching an asymptote. This type of reactor is therefore particularly poorly suited to the use of constant CO2 fluxes. Secondly, a batch reactor for a variable process does not maximize the available volumes. At the end of the reaction, a large part of the available volume is no longer used. Finally, CO2 access to the materials is not optimal, and gas diffusion phenomena in the absence of material flow can be slow and / or limited.

[0123] A continuous or semi-continuous reactor made of granular solid material such as that of the invention exhibits a smoothed, quasi-continuous CO2 consumption and can therefore be connected to a CO2 producer without having to store or liquefy the gas containing the CO2.

[0124] In one embodiment, the reactor body is partially gas-tight.

[0125] Level measuring device

[0126] The level of material in the body of the reactor is preferably measured by one or more level measuring devices such as level measuring sensors.

[0127] Thus, according to a preferred embodiment, the reactor body is equipped with at least one level measuring device for the granular solid material (carbonated or non-carbonated). This allows the feeding and extraction of the material to be controlled. In particular, it allows the flow rate of the granular solid material within the reactor body to be adjusted.

[0128] According to a particularly preferred embodiment of the invention, the reactor body is equipped with at least one injection device for a gas comprising CO2, and the granular solid material level measuring device is positioned above said injection device (i.e., upstream of said injection device or devices in a direction parallel to the direction of granular flow). This makes it possible to limit CO2 losses, as CO2 is readily absorbed by the material if the quantity of material is significant in the reactor body.

[0129] When there are several injection members, the granular solid material level measuring member is preferably positioned above the higher level injection member (i.e., closest to the first conveying member).

[0130] Other measuring devices

[0131] The reactor body can further be equipped with at least one CO2 pressure measuring device and / or at least one CO2 temperature measuring device and / or at least one humidity measuring device and / or at least one CO2 concentration measuring device.

[0132] Preferably, at least one CO2 pressure measuring device (respectively at least one temperature measuring device, at least one humidity measuring device, at least one CO2 concentration measuring device) is positioned in a high part of the reactor body, which can also be called the "gaseous sky".

[0133] Preferably, a second CO2 pressure measuring device (or, respectively, a second temperature measuring device, a second humidity measuring device, or a second CO2 concentration measuring device) is positioned in a lower part of the reactor body. This allows for the evaluation of the difference in carbonation rate between the upper and lower parts of the reactor.

[0134] According to a preferred embodiment of the invention, the reactor body is placed at a pressure less than or equal to 1.5 bar absolute, and preferably strictly less than 1.5 bar absolute. This makes it possible to obtain a good compromise between mechanical sizing, gas losses and carbonation performance.

[0135] Gas injection device(s) and gas diffusion device(s)

[0136] One or more gas injection device(s) including CO2 make it possible to maximize the quantity of CO2 in the gas stream made available in the reactor body and thus maximize the carbon yield.

[0137] In one embodiment, the reactor body is equipped or includes at least one set of gas injection devices comprising CO2 and / or a gas diffusion device comprising CO2.

[0138] In a preferred embodiment, the reactor body is equipped or includes at least one set of CO2 gas injection devices and at least one CO2 gas diffusion device, and particularly preferredly several sets of CO2 gas injection devices and several CO2 gas diffusion devices.

[0139] Preferably, a set of injection devices for a gas including CO2 comprises injectors positioned radially with respect to the direction of flow of the material in the reactor body. This allows the material to be exposed to a gas flow velocity field that maximizes the interaction between the material and the CO2.

[0140] Preferably, the reactor body is equipped with at least one set of CO2-containing gas injection devices in the form of a ring (ring of injection devices). When the reactor body comprises several sets, it then comprises several rings.

[0141] In one embodiment, a set of injection members comprises at least three injection members.

[0142] The injection devices are preferentially distributed so as to cover an internal periphery of the reactor body evenly.

[0143] In one embodiment, the gas injection devices are covered at least in part by a protective element such as a fixed hood positioned above.

[0144] The injection device(s) for a gas containing CO2 are preferably positioned inside and around the periphery of the reactor body. This facilitates the injection of the gas into the reactor body.

[0145] The gas diffusion device(s) are preferably configured to penetrate the reactor body in at least one central region. This ensures good access to CO2 for the central regions of the reactor, which are located, in particular, far from the peripheral regions where the injection devices are situated.

[0146] The gas diffusion organ(s) may be in the form of elongated elements, in particular extending in a direction parallel to a gravitational flow direction of the granular solid material within the reactor body.

[0147] In a preferred embodiment, the elongated element(s) are semi-flexible type pipes.

[0148] The elongated elements may advantageously comprise a gas-tight upper portion, intended to be connected to a gas supply device comprising CO2; and a lower portion comprising a plurality of orifices for allowing the gas to pass into the reactor body. Such a configuration optimizes the presence of CO2 in the areas of the reactor body where the reaction is to occur.

[0149] The reactor may further include a fixing or attachment system, preferably removable, carrying the gas diffusion element(s).

[0150] According to a preferred embodiment of the invention, the reactor body comprises an upper part and a lower part.

[0151] The upper part of the reactor body is advantageously conical in shape with the point facing upwards. This helps to limit the volume of gas not filled with material in the reactor.

[0152] In one embodiment, the reactor body is cylindrical in shape. This reduces manufacturing costs, wall wear, and dead volumes.

[0153] Gas extraction device

[0154] The reactor may further include a gas extraction device, preferably controllable, positioned in an upper part of the reactor body. This allows the extraction of gases from the air that have entered the reactor body with the material and / or in the gas stream containing CO2. This makes it possible to maintain a high CO2 concentration in the reactor body, improving the carbonation kinetics and the rate of CO2 capture.

[0155] Gas supply device comprising CO2

[0156] The reactor of the invention may further include a gas supply device for the reactor body comprising CO2 connected to said reactor body, and preferably connected to said injection device(s) and / or to said diffusion device(s).

[0157] Other provisions

[0158] According to a preferred embodiment, the reactor body, the feeding system and the extraction system are equipped with level measuring devices for the granular solid material (carbonated or non-carbonated).

[0159] The reactor of the invention operates preferably in a dry process, i.e., it preferentially uses solid materials in granular flow, which may have a water content by mass of less than approximately 20% relative to the dry material, and preferably less than approximately 11% relative to the dry material. In particular, it does not preferentially use liquids containing suspended materials to feed the reactor body, and even more preferably does not use liquids to feed the reactor.

[0160] The reactor of the invention operates preferentially in such a way as to have a gravity or downward granular flow and does not behave like a fluidized bed reactor. Fluidized bed reactors are suitable for small particle sizes and may require high energy consumption for larger particle sizes.

[0161] In a preferred embodiment of the invention, the first buffer volume has a volume Vj and the reactor body has a volume V2, so that Vi is less than or equal to about 30% of the volume V2.

[0162] In a preferred embodiment of the invention, the second buffer volume has a volume V3, such that V3 is less than or equal to about 30% of the volume V2.

[0163] In a preferred embodiment of the invention, several first buffer volumes V; are connected to the reactor body of volume V2, such that Vi< V2 for each i.

[0164] Use of the reactor

[0165] The invention has as its second object the use of a reactor conforming to the first object of the invention for carbonated a granular solid material.

[0166] The invention has as its third object the use of a reactor conforming to the first object of the invention to produce recycled carbonated concrete.

[0167] Carbonation process

[0168] The invention also has as a fourth object a carbonation process, characterized in that it is implemented in a reactor conforming to the first object of the invention, and in that it comprises at least the following steps: i) introduce a granular solid material into said first buffer volume, ii) convey said granular solid material from the first buffer volume towards the reactor body via the first conveying device, iii) inject and / or diffuse, preferably continuously, a gas comprising CO2 into the reactor body by means of said injection device and / or said diffusion device, to produce a granular carbonated solid material, iv) move said granular carbonated or partially carbonated solid material within the reactor body by gravity flow, towards the second conveying device, v) convey said granular carbonated solid material into the second buffer volume via the second conveying device, and vi) extract said solid granular carbonate material from the second buffer volume to the outside.

[0169] In the process of the invention, all the steps are preferably concurrent, except on the one hand for steps i) and ii) which are preferably non-concurrent and on the other hand for steps v) and vi) which are preferably non-concurrent.

[0170] During step i), the first buffer volume is filled with granular solid material via the feed system inlet.

[0171] Step i) is preferably carried out for a sufficient duration for the material to reach a so-called "high" level in the first buffer volume, said first buffer volume being filled with said material.

[0172] Step ii) allows the reactor body to be filled with said granular solid material.

[0173] Step iii) is preferably carried out at a quasi-constant flow rate of gas comprising CO2.

[0174] During step iii), the pressure in the reactor initially increases and then decreases. The carbonation reaction takes place.

[0175] After a time programmed by the user and / or depending on the evolution of the pressures in the reactor, steps ii) and iv) are implemented to continuously extract said solid granular carbonate material.

[0176] In parallel (i.e. concurrently), step i) is implemented to introduce an equivalent amount of material.

[0177] Measuring pressures and CO2 concentrations provides an indication of the progress of the carbonation reaction, which is controlled by the injection and withdrawal of material. The flow of material is almost continuous in the reactor.

[0178] The process may further include a step of modulating a CO2 flow rate, with the aim of maintaining a pressure lower or higher than a target pressure and as close as possible to atmospheric pressure at the time of opening the second and / or third shut-off valve. During operation, for a quantity of newly introduced material, the pressure in the reactor body drops to a value close to or lower than ambient pressure because CO2 continues to be consumed by the non-carbonated granular solid material. The first shut-off valve of the feed system opens to rapidly load a new quantity of granular solid material into the first buffer volume (step i)).

[0179] During the process, the second conveying element will stop and the fourth closing element will close. The fifth closing element of the extraction system will then open to release the granular carbonate solid material in a very short time. The fifth closing element will then close, and then the fourth closing element will open and the reactor will resume operation.

[0180] Steps i) to vi) are preferably conditioned by the measurement of several parameters such as the level of granular solid material in the reactor body, the pressure in an upper part of the reactor body, the pressure variation over time and / or the pressure in a lower part of the reactor body.

[0181] When the "high" level measuring device in granular solid material of the reactor body indicates that the "high" level has not been reached: - if the upper part of the reactor body has a pressure lower than the ambient pressure, the CO2 injection rate is momentarily increased, - if the upper part of the reactor body has a pressure higher than the ambient pressure, the pressure is lowered.

[0182] When the pressure variation over time is large, the material in the reactor body is still weakly carbonated. The pressure is lowered by continuing the reaction. The pressure decreases, and then the CO2 injection is increased.

[0183] When the pressure variation over time is small, the material in the reactor body is already partially carbonated. The pressure is lowered by reducing the CO2 injection, and the pressure in the upper part of the reactor is allowed to approach ambient pressure before injecting granules (i.e., by opening the second and / or third shut-off valve, or by increasing the injection speed of the first conveyor). By injecting the granular solid material, the carbonation reaction will resume, and the pressure will begin to fall again more rapidly.

[0184] When the "high" level measuring device in the granular solid material of the reactor body indicates that the "high" level has been reached: by repeatedly injecting granular solid material, a "high" level sensor will be triggered. At this point, either the pressure variation over time is large and the CO2 introduction is slightly increased, or the pressure variation over time is small and in this case the reactor draining from the bottom is momentarily increased, via step iv).

[0185] Due to the increased draining of the reactor, the "high" level will no longer be reached after a certain time, and we find ourselves in the first stage.

[0186] When there is no longer any pressure variation and the pressure in the upper part is greater than atmospheric pressure, the reactor draining is first momentarily increased via step iv), then a new granular solid material is injected via step ii). The pressure will then start to decrease again and we are back in the first step.

[0187] The concepts of low or high pressure variation over time, and the duration for which the reactor emptying is increased, are calibrated according to the pressure reached at the bottom of the reactor. If the pressure at the bottom of the reactor drops rapidly (either compared to a reference value and / or compared to the pressure at the top of the reactor), this means that the granular solid material is not yet fully carbonated and therefore the reactor must be emptied slowly. If the pressure at the bottom of the reactor varies very slowly or not at all, then this means that the granular solid material is carbonated.

[0188] An optimal operating mode leads to draining the reactor at a rate where the pressure at the bottom of the reactor is almost fixed and the pressure at the top of the reactor oscillates slightly (as a function of time) around atmospheric pressure.

[0189] The operator can also choose a target material flow rate (by varying the CO2 flow rate) and / or a target CO2 flow rate by varying the material flow rate.

[0190] The reactor of the invention has the following advantages: - near-continuous flow of gas and materials: this allows for greater productivity and direct operation with constant CO2 flow rates, unlike batch reactors, - increasing reaction kinetics by bringing the gas into contact with the injection devices in a localized region at the beginning of the process, where the kinetics are high and CO2 consumption is greatest, - limited gas losses, via the closing devices, the gas extraction devices in the first and second buffer volumes as well as the control of the pressure in the reactor body by pressure control (via the injection of more material than CO2), - quantification of leaks, via the performance of mass balance in the first and second buffer volumes before and after each opening.

[0191] According to a particularly preferred embodiment of the invention, the method comprises at least the following steps: (i) introduce a granular solid material into said first buffer volume, until a certain level of material is detected in the first buffer volume, preferably using at least one material level measuring device, with the first closing device open and the second closing device closed; (ii) close the first closing device, i2) perform a mass balance in the first buffer volume, i3) open the second and / or third locking mechanism, and ii) to bring said granular solid material from the first buffer volume to the reactor body via the first conveying device, in order to fill the reactor body with said granular solid material, (i) stop the first conveyor unit if it is motorized ii2) close the second and / or third closing mechanism, ii3) perform a mass balance in the first buffer volume, ii4) open the first closing mechanism, iii) inject and / or diffuse a gas comprising CO2 within the reactor body by means of said injection device and / or said diffusion device, to produce a solid granular carbonate material, iiil) open the fourth locking mechanism, the fifth locking mechanism being closed, (iv) to move said solid granular carbonated or partially carbonated material within the reactor body by gravity flow, towards the second conveying element, (v) to bring said solid granular carbonate material into the second buffer volume by passing through the second conveying member of the reactor body, the fifth closing member being closed, vl) stop the second conveyor, v2) close the fourth closing mechanism, v3) perform a mass balance in the second buffer volume, v4) remove the residual gas in the second buffer volume with the extraction device to reinject it into the reactor body if the CO2 level is sufficiently high, v5) repressurize the second buffer volume by allowing ambient air to enter through the repressurization system, v6) open the fifth locking mechanism, vi) extract said solid granular carbonate material from the second buffer volume to the outside, vi) close the fifth closing mechanism, and vi2) perform a mass balance in the second buffer volume, vi3) open the fourth closing mechanism.

[0192] In the process of the invention, all the steps are preferably concurrent, except on the one hand for steps i) and ii) which are preferably non-concurrent and on the other hand for steps v) and vi) which are preferably non-concurrent.

[0193] In some embodiments, the gas flow rate is quasi-constant between two reactor openings and the material flow is quasi-continuous. This makes it possible to work more effectively with constant CO2 flow rates without having to manage excessively large gas storage volumes.

[0194] According to a particularly preferred embodiment of the invention, the method comprises at least the following steps: i) introduce a granular solid material into a set of N initial buffer volumes V1, V2, ..., VN, with N greater than 1 comprising i) 1 introduce a granular solid material into a first buffer volume V1 i)2 introduce a granular solid material into a first buffer volume V2, then i) Introduce a granular solid material into a first buffer volume VN; ii) Bring said granular solid material from the first buffer volume VI to the reactor body via the first conveying device, then ii)2) bring said granular solid material from the first buffer volume V2 to the reactor body via the first conveying device and then continue for the other Nl first buffer volumes ii)N) bring said granular solid material from the first buffer volume VN to the reactor body via the first conveying device iii) continuously inject and / or diffuse a gas comprising CO2 into the reactor body by means of said injection device and / or said diffusion device, to produce a carbonated granular solid material, iv) move said carbonated or partially carbonated granular solid material within the reactor body by gravity flow, towards the second conveying device, v) bring said carbonated granular solid material into the second buffer volume by way of the second conveying device of the reactor body, and vi) extract said carbonated granular solid material from the second buffer volume to the outside.

[0195] In this embodiment, steps ii)1 to ii)N are preferably concurrent. This allows for a smoother introduction of granular solid material into the reactor.

[0196] In the process of the invention, all the steps are preferably concurrent, except on the one hand for the same first buffer volume J (with J between 1 and N), steps i)J and ii)J which are preferably non-concurrent and, on the other hand, steps v) and vi) which are preferably non-concurrent. Brief description of the drawings

[0197] The invention is illustrated by the figures and examples that follow, but are not limited to them. Figure [1] shows a schematic representation of a reactor according to the invention. Figure 2 shows a schematic representation of a reactor according to the invention. Figure 3 shows a schematic representation of a reactor according to the invention.

[0198] Figure [1] represents a carbonation reactor comprising: - a reactor body (10) equipped with several CO2-containing gas injection devices (101a, 101b) configured to inject said gas into the reactor body (10), - a system for feeding (11) the reactor body (10) with granular solid material, and - an extraction system (12) of a solid granular carbonate material from the reactor body (10). The power supply system (11) includes: - a first buffer volume (110) configured to receive said granular solid material, - an inlet (111) configured to supply said first buffer volume (110) with said granular solid material, and - a first conveying element (112) of said granular solid material from the first buffer volume (110) to the reactor body (10). The extraction system (12) comprises: - a second buffer volume (120) configured to receive said solid granular carbonate material, - a second conveying element (121) for the granular carbonate solid material from the reactor body (10) to a second buffer volume (120), and - an outlet (122) configured to extract said solid granular carbonate material from said second buffer volume (120). The feeding system (11) and / or the extraction system (12), and preferably the first and / or second conveying element (112, 121), are configured to move said solid granular material into the body of the reactor (10) by gravity flow, preferably semi-continuous.

[0199] The feeding system (11) may further include an actuated closure device (113) configured to isolate the first buffer volume (110) from the outside (i.e., from ambient air). The feeding system (11) may further include an actuated closure device (114) configured to block access of the granular solid material (from the first buffer volume (110)) to the first conveying device (112).

[0200] The extraction system may further include an actuated closure device (123) configured to block access of the granular carbonate solid material (from the second conveying device (121)) to the second buffer volume (120). The extraction system may further include an actuated closure device (124) configured to isolate the second buffer volume from the outside, and preferably to isolate the reactor body from ambient air. enter the second buffer volume from the outside (when the material is released to the outside).

[0201] The reactor body (10) comprises one or more gas injection devices (101), and in particular two sets, each set comprising a plurality of gas injection devices (101a, 101b) for injecting the gas comprising CO2. Each set is in the form of a ring (ring of injection devices). The injection devices (101a, 101b) are preferably distributed so as to evenly cover an inner periphery of the reactor body (10).

[0202] The reactor may further include a gas extraction device (103), preferably controllable, positioned in an upper part of the reactor body (10). The reactor may further include a gas extraction device (125), preferably controllable, positioned in an upper part of the second buffer volume (120).

[0203] The reactor body (10) is preferably equipped with at least one level measuring device (104) for the granular solid material (carbonated or non-carbonated). This allows the feeding and extraction of the material to be controlled. In particular, it allows the flow rate of the granular solid material within the reactor body (10) to be adjusted.

[0204] The first conveying element (112) is preferably a screw conveyor.

[0205] The second conveying element (121) is preferably a screw conveyor.

[0206] Fig. 2 represents a reactor having the same characteristics as that of Fig. 1, except with regard to the supply of CO2 into the body of the reactor which is carried out via gas diffusion elements (102), preferably in the form of elongated elements, in particular which plunge into the body of the reactor (10) or extend in a direction parallel to a direction of gravitational flow of the granular solid material within the body of the reactor (10).

[0207] The reactor can combine the characteristics of the reactor of [Fig.1] and that of [Fig.2], i.e. include gas diffusion elements (102) and gas injection elements (101a, 101b).

[0208] Figure 3 represents a carbonation reactor comprising: - a reactor body (10) equipped with several CO2-containing gas injection devices (101) configured to inject said gas into the reactor body (10), - a system for feeding (11) the reactor body (10) with granular solid material, and - an extraction system (12) of a solid granular carbonate material from the reactor body (10). The power supply system (11) includes: - a first buffer volume (110) configured to receive said granular solid material, - an inlet (111) configured to supply said first buffer volume (110) with said granular solid material, and - a first conveying element (112) of said granular solid material from the first buffer volume (110) to the reactor body (10). The extraction system (12) comprises: - a second buffer volume (120) configured to receive said solid granular carbonate material, - a second conveying element (121) for the granular carbonate solid material from the reactor body (10) to a second buffer volume (120), and - an outlet (122) configured to extract said solid granular carbonate material from said second buffer volume (120). The feeding system (11) and / or the extraction system (12), and preferably the first and / or second conveying element (112, 121), are configured to move said solid granular material into the body of the reactor (10) by gravity flow, preferably semi-continuous.

[0209] The feeding system (11) may further include an actuated closure device (113) configured to isolate the first buffer volume (110) from the outside (i.e., from ambient air). The feeding system (11) may further include an actuated closure device (115) configured to block access of the granular solid material (from the first conveying device (110)) to the reactor body (10).

[0210] The extraction system may further include an actuated closure device (123) configured to block access of the granular carbonate solid material (from the second conveying device (121)) to the second buffer volume (120). The extraction system may further include an actuated closure device (124) configured to isolate the second buffer volume from the outside, and preferably to isolate the reactor body from ambient air that may enter the second buffer volume from the outside (during the release of the material to the outside).

[0211] The reactor body (10) comprises one or more gas injection devices (101), and in particular six assemblies, each assembly comprising a plurality of gas injection devices (101) for injecting the gas comprising CO2. Each assembly is in the form of a ring (ring of injection devices). The injection devices (101) are preferably distributed so as to evenly cover an inner periphery of the reactor body (10).

[0212] The reactor may further include a gas extraction device (125), preferably controllable, positioned in an upper part of the second buffer volume (120).

[0213] The reactor body (10) is preferably equipped with at least one level measuring device (104) for the granular solid material (carbonate or non-carbonate). This allows the feeding and extraction of the material to be controlled. In particular, it allows the flow rate of the granular solid material within the reactor body (10) to be adjusted.

[0214] The first conveying element (112) is preferably a non-motorized tube, cone or pipe.

[0215] The second conveying element (121) is preferably a screw conveyor.

Claims

Demands

1. Carbonation reactor comprising: - a reactor body (10) equipped with at least one CO2-containing gas injection device (101, 101a, 101b) configured to inject said gas into the reactor body and / or at least one CO2-containing gas diffusion device (102) configured to diffuse said gas into the reactor body (10), - a granular solid material feeding system (11) for the reactor body (10), and - a carbonated granular solid material extraction system (12) from the reactor body (10), characterized in that: * the feeding system (11) comprises: - a first buffer volume (110) configured to receive said granular solid material, - an inlet (111) configured to supply said first buffer volume (110) with said granular solid material, and - a first conveying device (112) of said granular solid material from the first buffer volume (110) to the reactor body (10),and * the extraction system (12) comprises: - a second buffer volume (120) configured to receive said granular carbonated solid material, - a second conveying element (121) for the granular carbonated solid material from the reactor body (10) to said second buffer volume (120), and - an outlet (122) configured to extract said granular carbonated solid material from said second buffer volume, and in that the feeding system (11) and / or the extraction system (12), and in particular the first and / or the second conveying element (112, 121), are configured to move said granular solid material into the reactor body (10) by gravity flow.

2. Reactor according to claim 1, characterized in that the feeding system (11) includes an actuable closing device (113) configured to isolate the first buffer volume (110) from the outside.

3. Reactor according to claim 1 or 2, characterized in that the extraction system (12) includes an actuable closure device (124) configured to isolate the second buffer volume (120) from the outside.

4. Reactor according to any one of the preceding claims, characterized in that the second conveying member (121) is a screw conveyor.

5. Reactor according to any one of the preceding claims, characterized in that the first conveying member (112) is a tube, a cone, a non-motorized pipe, or a screw conveyor.

6. Reactor according to any one of the preceding claims, characterized in that the reactor body (10) is equipped with at least one level measuring device for the granular solid material (104).

7. Reactor according to claim 6, characterized in that the reactor body (10) is equipped with at least one CO2 gas injection device (101, 101a, 101b) and the granular solid material level measuring device (104) is positioned above said injection device (101, 101a, 101b).

8. Reactor according to any one of the preceding claims, characterized in that the reactor body (10) is equipped with at least one set of CO2 gas injection devices (101, 101a, 101b) and at least one CO2 gas diffusion device (102).

9. Reactor according to any one of the preceding claims, characterized in that the first buffer volume (110) and / or the second buffer volume (120) is equipped with a CO2 pressure measuring device and / or a temperature measuring device and / or a CO2 concentration measuring device and / or a humidity measuring device.

10. Reactor according to any one of the preceding claims characterized in that it comprises a gas extraction device (125) positioned in an upper part of the second buffer volume (120) and / or a gas extraction device (103) positioned in an upper part of the reactor body (10).

11. Reactor according to claim 10, characterized in that the reactor further comprises a separation system for separating a gas stream extracted from the second buffer volume (120) and / or the body of the reactor (10) in two fractions: a fraction enriched in CO2 and a fraction depleted in CO2.

12. Use of a reactor as defined in any of the preceding claims for carbonated granular solid material.

13. Use of a reactor as defined in any one of claims 1 to 11, to produce recycled carbonated concrete.

14. Carbonation process, characterized in that it is carried out in a reactor as defined in any one of claims 1 to 11, and in that it comprises at least the following steps: i) introducing a granular solid material into said first buffer volume (110), ii) conveying said granular solid material from the first buffer volume (110) to the reactor body (10) via the first conveying member (112), iii) injecting and / or diffusing a gas comprising CO2 into the reactor body by means of said injection member (101, 101a, 101b) and / or said diffusion member (102), to produce a carbonated granular solid material, iv) moving said carbonated or partially carbonated granular solid material within the reactor body (10) by gravity flow, towards the second conveying member (121),(v) bring said granular carbonate solid material into the second buffer volume (120) via the second conveying element (121), and (vi) extract said granular carbonate solid material from the second buffer volume (120) to the outside.

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