Apparatus and method for forced carbonization of fine fractions of recycled concrete

Abstract

The invention relates to a device (1) for the forced carbonization of a fine fraction of recycled concrete, comprising:-a carbonization reactor (2) in which the fine fraction can and is intended to be brought into contact with a gas containing carbon dioxide,-first water spraying means (11) in which the fine fraction can be brought into contact with the gas containing carbon dioxide, and-second water spraying means (12) in which the gas containing carbon dioxide can be brought into contact with the gas containing carbon dioxide, the invention relates to a device for controlling the temperature and the relative humidity of a gas containing carbon dioxide, comprising:-first water spraying means (16) capable of increasing the moisture content of the fine fraction, and-regulating means (16) capable of managing the temperature and the relative humidity of the gas containing carbon dioxide, the device comprising a computer control unit (6), the computer control unit is capable of controlling the first spraying means (11) and the means (16) for conditioning the carbon dioxide-containing gas.

Description

Technical Field

[0001] The present invention relates to a device and a method for the forced carbonation of a fine fraction originating from a previous dissociation process of recycled concrete. More specifically, the present invention relates to a device and a method consisting in capturing carbon dioxide in recycled concrete. Background Art

[0002] Carbon dioxide is a greenhouse gas. The amount of carbon dioxide in the Earth's atmosphere affects climate change.

[0003] There are several technologies for reducing carbon dioxide emissions. One of these technologies is to capture carbon dioxide in recycled concrete, in particular recycled concrete from the demolition of old buildings or construction projects.

[0004] Recycled concrete includes hydrated cement slurry. To some extent, hydrated cement slurry can be used as a carbon dioxide well. In other words, hydrated cement slurry can capture carbon dioxide by bringing it into direct contact with carbon dioxide so as to reduce the amount of this greenhouse gas in the atmosphere.

[0005] In order to properly load these recycled concretes with carbon dioxide, these concretes are exposed to carbon dioxide for several hours. This is incompatible with industrial rates.

[0006] Recognizing the problem, and in order to achieve industrial rates, attempts have been made to reduce the time the fine fraction is exposed to carbon dioxide to tens of minutes. Mixers designed to produce agitation have been used, however the capture rate of carbon dioxide in the recycled concrete has proven to be insufficient, reducing the efficiency of the process and therefore the benefits of these operations.

[0007] Therefore, current technology still needs to be improved. The goal is to be able to load recycled concrete with carbon dioxide at industrial rates (ie, within tens of minutes at most). The goal is to unlock the technical limitations that prevent manufacturers from using recycled concrete as a carbon dioxide well. Summary of the invention

[0008] For this purpose, firstly a device for forced carbonization of a fine fraction of recycled concrete is provided, said device comprising:

[0009] a carbonization reactor in which said fine fraction can and is intended to be brought into contact with a gas containing carbon dioxide,

[0010] - first water spraying means capable of increasing the moisture content of said fine fraction, and

[0011] - regulating means capable of managing the temperature and the relative humidity of the carbon dioxide containing gas,

[0012] The device comprises a computer control unit capable of controlling the first spraying means and the means for regulating the gas comprising carbon dioxide.

[0013] Various additional features may be provided alone or in combination:

[0014] - the first spraying device is arranged upstream of the carbonization reactor according to the movement direction of the fine fraction, or is arranged inside the carbonization reactor and is located near the inlet of the fine fraction;

[0015] - the device comprises first means for measuring the moisture content in the fine fraction, the first measuring means being arranged upstream of the carbonization reactor according to the direction of movement of the fine fraction;

[0016] - the apparatus comprises second means for measuring the relative humidity and / or the temperature of the gas in the carbonization reactor;

[0017] - the device comprises a circuit for injecting a gas containing carbon dioxide in the carbonization reactor, the gas injection circuit containing carbon dioxide being fluidly connected to a supply source originating from combustion fumes;

[0018] The carbon dioxide-containing gas injection circuit comprises:

[0019] - an outlet dryer intended to dry the carbonized fine fraction at the outlet of the carbonization reactor,

[0020] a pneumatic separation device capable of separating, on the one hand, the carbon dioxide-containing gas and, on the other hand, the carbonized and dried fine fraction, said separation device comprising a first outlet through which the carbonized and dried fine fraction is intended to be discharged,

[0021] a volume distribution system capable of managing the volume of gas containing carbon dioxide sent towards the carbonization reactor,

[0022] - a device for conditioning the gas containing carbon dioxide, the device being able to modify the relative humidity and / or the temperature of the gas containing carbon dioxide,

[0023] - means for injecting the carbon dioxide containing gas into the carbonization reactor.

[0024] The invention further relates to a method for the forced carbonization of a fine fraction originating from recycled concrete, which method can be implemented in a device as described above, said method comprising the following steps:

[0025] - a step of adjusting the fine fraction so that the fine fraction has a predetermined moisture content substantially equal to a set point value, and

[0026] - a step of regulating said carbon dioxide containing gas such that said relative humidity and / or said temperature of said gas is substantially equal to a set point value,

[0027] - a step of supplying said carbonization reactor with said fine fraction originating from recycled concrete comprising hydrated cement paste, said fine fraction having a particle size less than or equal to 16 mm, said fine fraction having been previously conditioned during said step of conditioning said fine fraction,

[0028] - a step of injecting said carbon dioxide-containing gas into said carbonization reactor, said gas having been previously conditioned during said gas conditioning step,

[0029] - a step of carbonizing said fine fraction in said carbonization reactor.

[0030] Various additional features may be provided alone or in combination:

[0031] - the method comprises a step of measuring the moisture content in the fine fraction, comparing the measurement result with a set point value, in which method the amount of water injected upstream of the carbonization reactor is adjusted so that the moisture content in the fine fraction is substantially equal to the set point value;

[0032] - the method comprises a step of measuring the relative humidity and / or the temperature of the gas in the carbonization reactor, comparing each of the measurements with a set point value, in which method the relative humidity and / or the temperature of the carbon dioxide-containing gas is modified during the step of conditioning the gas such that each of the relative humidity and / or the temperature in the carbonization reactor is substantially equal to the set point value;

[0033] - said method comprises a step of drying said fine fraction at said outlet of said carbonization reactor by means of fumes originating from combustion, said fine fraction being dried after carbonization;

[0034] - the carbon dioxide injected into the carbonization reactor originates from fumes originating from combustion;

[0035] - the method comprises a pneumatic separation step carried out by the pneumatic separation device, during which the dried and carbonized fine fraction is separated from the fumes;

[0036] - the method comprises a step of volumetric distribution in order to send a predetermined amount of carbon dioxide towards the gas regulating device;

[0037] - the temperature in the carbonization reactor is between 30°C and 80°C, preferably 40°C;

[0038] - the relative humidity of the gas in the carbonization reactor is between 40% and 100%;

[0039] - the residence time of the fine fraction in the carbonization reactor is between 20 and 120 minutes;

[0040] - the pressure inside the carbonization reactor is substantially equal to atmospheric pressure;

[0041] - the particle size of the fine fraction is less than or equal to 6 mm. BRIEF DESCRIPTION OF THE DRAWINGS

[0042] Other features and advantages of the present invention will appear on reading the following detailed description, for understanding of which reference will be made to the accompanying drawings, in which:

[0043] [ Figure 1 ] Figure 1 is a schematic illustration of a device according to the invention. DETAILED DESCRIPTION

[0044] Figure 1 A forced carbonization plant 1 is shown. The plant 1 comprises a carbonization reactor 2. The carbonization reactor 2 is intended to take up the fine fraction of recycled concrete. The carbonization reactor 2 is able to bring the fine fraction into contact with carbon dioxide.

[0045] “Recycled concrete” is understood to mean concrete originating from building demolition or engineering construction, as well as waste originating from concrete production units, such as, but not limited to, washing residues from vats, leftovers from gyros.

[0046] The fine fraction corresponds to the fraction of recycled concrete that has been subjected to abrasion or has been ground and has a particle size less than or equal to 16 mm. Advantageously, the particle size of the fine fraction is less than or equal to 6 mm.

[0047] The carbonization reactor 2 has an inlet 9 through which the fine fraction enters and an outlet 10 through which the fine fraction is discharged.

[0048] The apparatus 1 comprises first water spraying means 11 capable of spraying water onto the fine fraction. Figure 1 In the embodiment shown in FIG. 1 , the first spraying device 11 is arranged upstream of the carbonization reactor 2 according to the movement direction of the fine fraction. According to a variant not shown, the first spraying device 11 is arranged in the vicinity of the internal inlet 9 of the carbonization reactor 2.

[0049] The first spraying device 11 is fluidically connected to the water tank 3 .

[0050] The first spraying device 11 allows water to be sprayed directly onto the fine fraction in order to increase its moisture content.

[0051] By acting on the moisture content of the fine fraction at the inlet 9 of the carbonization reactor 2, the fine fraction is set under optimal conditions for being loaded with carbon dioxide during its residence in said carbonization reactor 2. By adjusting the fine fraction so as to obtain an optimal moisture content in said fine fraction, the chemical reactivity of carbon dioxide with the fine fraction in the carbonization reactor 2 is improved. Thus, it becomes possible to obtain carbonization of the fine fraction at industrial rates.

[0052] Advantageously, the device 1 comprises first means 7 for measuring the moisture content of the fine fraction. The measuring means 7 are arranged upstream of the carbonization reactor 2. Figure 1 As shown, the measuring device 7 is arranged upstream of the spraying device 11. Figure 1 In a variant not shown in the drawing, the measuring device 7 can be arranged downstream of the spraying device 11. This consists of a sensor capable of transmitting the acquired data to the unit 6 in real time.

[0053] The fine fraction initially has a moisture content which is lower than or equal to the determined set point value. "Initially" is to be understood as before the first spraying device 11 according to the direction of movement of the fine fraction.

[0054] The carbonization reactor 2 is in the form of a rotating drum 4. The rotating drum 4 is driven in rotation by at least one motor (not shown in the figure).

[0055] Advantageously, the device 1 comprises a computer control unit 6. The unit 6 allows the device 1 to be controlled.

[0056] Advantageously, the device 1 comprises second means 8 for measuring the relative humidity and the temperature of the gases in the carbonization reactor 2. This consists of a sensor measuring the relative humidity and the temperature of the gases in the carbonization reactor 2 and capable of transmitting the data obtained to the unit 6 in real time.

[0057] Advantageously, the device 1 comprises an outlet dryer 13. The outlet dryer 13 is capable of drying the carbonized fine fraction. Drying the carbonized fine fraction allows making it suitable for transport and storage.

[0058] The outlet dryer 13 is arranged at the outlet 10 of the carbonization reactor 2. The outlet dryer 13 thus arranged is able to dry the carbonized fine fraction immediately after it comes out of the carbonization reactor 2.

[0059] Advantageously, the outlet dryer 13 is fluidly connected to a supply 14 of fumes originating from combustion. This combustion is, for example, a combustion that occurs in the burners of a cement kiln. Thus, the fumes originating from the kiln, loaded with carbon dioxide, are cooled in the outlet dryer 13 and, at the same time, humidified. This has advantages, since these fumes contain carbon dioxide and will come into contact with the fine fraction in the carbonization reactor 2, as will be described later. In fact, the applicant has determined after tests that the carbonization reaction is more effective when the carbon dioxide is at a low temperature.

[0060] Advantageously, the device 1 comprises a circuit 60 for injecting a gas containing carbon dioxide. This circuit 60 comprises, arranged in the following order according to the direction of flow of the smoke:

[0061] - outlet dryer 13,

[0062] - Pneumatic separation device 17,

[0063] - volume distribution system 20,

[0064] - a device 16 for conditioning a gas containing carbon dioxide,

[0065] - Means 15 for injecting a gas containing carbon dioxide.

[0066] The elements 13 , 17 , 20 , 16 , 15 are in sequence fluidically connected to one another.

[0067] The loop 60 is fluidly connected to the fume supply source 14. Thus, the fume is conveyed to the carbonization reactor 2 and injected into said carbonization reactor.

[0068] Advantageously, the device 1 comprises a pneumatic separation device 17 arranged downstream of the outlet dryer 13 for drying the fine fraction according to the flow direction of the fumes and the fine fraction indicated by the arrow 24. The fumes convey the fine fraction from the outlet dryer 13 to the pneumatic separation device 17. The pneumatic separation device 17 allows the fine fraction to be separated from the fumes. At a first outlet 18 of the pneumatic separation device 17, the carbonized fine fraction is discharged, while at a second outlet 19 of the pneumatic separation device 17, the fumes are sent in the direction of the conditioning device 16. Advantageously, the pneumatic separation device 17 is of cyclone type and may further comprise a dynamic separator.

[0069] Advantageously, the device 1 comprises a volumetric distribution system 20. The volumetric distribution system 20 is arranged between the pneumatic separation device 17 and the regulating device 16. The volumetric distribution system 20 allows managing the volume of the fumes sent to the device 15 for injecting gas into the carbonization reactor 2, so as to send only the necessary amount of fumes in said carbonization reactor 2. Thus, only the fumes to be delivered to the carbonization reactor 2 are regulated. The rest of the fumes are discharged towards the exhaust.

[0070] The regulating device 16 allows regulating the moisture content and the temperature of the gas containing carbon dioxide. In fact, relative humidity and temperature are the main factors in the carbonization reaction, and the regulating device 16 is used to optimally manage these factors.

[0071] By optimizing the temperature and relative humidity of the gas in the chamber of the carbonization reactor 2 , the carbonization reaction is accelerated, which allows reducing the residence time of the fine fraction in said carbonization reactor 2 .

[0072] The increase in relative humidity of the gas is carried out directly by adding water or water vapor. The reduction in relative humidity of the gas is obtained by condensation of water vapor. Therefore, the packaging device 16 is in particular in fluid connection with the water tank 3 so that said device 16 draws water into it. Advantageously, the regulating device 16 is able to cool and heat the carbon dioxide-containing gas to obtain an optimal temperature. Therefore, the regulating device 16 is able to modify the temperature of the carbon dioxide-containing gas.

[0073] The regulating device 16 is arranged between the volumetric distribution system 20 and the gas injection device 15. The regulating device 16 thus arranged allows managing the relative humidity and the temperature of the carbon dioxide-containing gas before injecting said gas into the carbonization reactor 2.

[0074] In a preferred embodiment, the carbonization reactor 2 has a length substantially equal to 15 meters and a diameter of 1.6 meters. The carbonization reactor 2 is arranged so as to form an angle substantially equal to 2 degrees with the horizontal plane. The rotation speed is substantially equal to 1.5 revolutions per minute.

[0075] Next, the forced carbonization process of the implementation device will be described.

[0076] The fine fraction reaches the apparatus 1 via the inlet 22 .

[0077] The method comprises a step of regulating the fine fraction. The particle size of the fine fraction is less than or equal to 16 mm. The fine fraction is produced by grinding or abrasion of recycled concrete. The fine fraction of recycled concrete (i.e., a fine fraction with a particle size less than 16 mm) is used for carbonization because its properties are favorable for carbon dioxide loading. Advantageously, the particle size of the fine fraction is less than or equal to 6 mm, and its properties are optimal for carbon dioxide loading. The fine fraction comprises a hydrated cement slurry. This hydrated cement slurry has carbon dioxide capture properties. This step of regulating the fine fraction consists in managing the moisture content of the fine fraction upstream of the carbonization reactor 2. The management of the moisture content is carried out by performing a water injection operation on the fine fraction. The operation of injecting water upstream of the carbonization reactor 2 is carried out by a first spraying device 11, which allows the fine fraction to be sprinkled with water. This regulation of the fine fraction allows its carbon dioxide capture properties to be improved.

[0078] Advantageously, the method comprises a step of conditioning the gas containing carbon dioxide. During this conditioning step, the gas containing carbon dioxide is conditioned by regulating its temperature and its relative humidity to obtain an optimal temperature and relative humidity in the carbonization reactor 2. This step is performed by the regulating device 16. The relative humidity corresponds to the ratio of the partial pressure of steam to the saturated vapor pressure in the carbonization reactor 2. Therefore, the purpose is to maintain an optimal temperature and relative humidity in the carbonization reactor 2 to increase the kinetics of carbon dioxide capture by the fine fraction.

[0079] The method comprises the step of supplying the carbonization reactor 2 with the fine fraction conditioned during the step of conditioning the fine fraction.

[0080] Advantageously, the method comprises a step of injecting a gas containing carbon dioxide into the carbonization reactor 2. In the embodiment shown in the figures, fumes originating from the combustion in the kiln and containing carbon dioxide are injected into the carbonization reactor 2.

[0081] Advantageously, the method comprises a step of carbonizing the fine fraction in a carbonization reactor. This step is performed by bringing the fine fraction into direct contact with a gas containing carbon dioxide in the carbonization reactor 2.

[0082] Advantageously, the method comprises a step of measuring the moisture content in the fine fraction. This step is performed by means of a first device 7 for measuring the moisture content in the fine fraction. The measurement result obtained is sent to the control unit 6. The control unit 6 compares the measurement result with a predetermined set point value. Several scenarios may then occur:

[0083] - if the measured moisture content is below the set point value, the control unit 6 controls the first spraying device 11 to spray water onto the fine fraction;

[0084] - If the measured moisture content is equal to the set point value, the control unit 6 controls the first injection means not to spray water onto the fine fraction.

[0085] Advantageously, the method comprises the step of measuring the relative humidity and the temperature in the carbonization reactor 2 by means of the second measuring device 8. The measurements obtained are sent to the control unit 6. The control unit 6 compares the measurement results with the set point values. The control unit 6 then controls the regulating device 16 to regulate the carbon dioxide-containing gas so that its relative humidity and its temperature are substantially equal to the set point values.

[0086] Advantageously, the relative humidity in the carbonization reactor 2 is between 40% and 100%. Therefore, the set point value of the relative humidity is included in this interval. The applicant has determined that the relative humidity included in this interval allows to obtain sufficiently rapid carbonization reaction kinetics to obtain industrial rates.

[0087] Advantageously, the temperature in the carbonization reactor 2 is between 30° C. and 80° C. Therefore, the set point value of the temperature is comprised in this interval. The Applicant has determined that the temperatures comprised in this interval allow to obtain sufficiently rapid carbonization reaction kinetics to obtain industrial rates.

[0088] Once the fine fraction has completed its stay in the carbonization reactor 2 and has thus been carbonized, it is dried by means of the outlet dryer 13. As mentioned before, the hot gases used in the outlet dryer 13 and passed through the substance originate from combustion, for example that of a cement kiln.

[0089] refer to Figure 1 The smoke from the outlet dryer 13 conveys the fine fraction to the pneumatic separation device 17. The carbonized and dried fine fraction is discharged through the first outlet 18. The smoke is discharged through the second outlet 19.

[0090] The method comprises a step of volumetric distribution of the smoke. At the outlet of the pneumatic separation device 17, the smoke is sent to a volumetric distribution system 20. During this step, the volumetric distribution device sends a given amount of smoke to the regulating device 16. The rest of the smoke is discharged through the exhaust device 25. In fact, it is advantageous to regulate only the necessary amount of smoke in order to maximize the overall efficiency of the device.

[0091] At the outlet of the volumetric distribution system 20, the smoke is sent to the conditioning device 16 to regulate its relative humidity and its temperature. In fact, and to the extent that the smoke is used as a gas containing carbon dioxide in the carbonization reactor 2, it is advantageous to condition the smoke so as to obtain suitable and optimal conditions for the carbonization reaction in the carbonization reactor 2.

[0092] The combustion fumes which have been previously conditioned and then decarbonized (ie at least partially cleansed of their carbon dioxide into the carbonization reactor 2) are then passed through Figure 1 In a variant, the decarbonized fumes can be sent to another element of the device.

[0093] Advantageously, the residence time of the fine fraction in the carbonization reactor 2 is between 20 and 120 minutes. This duration is acceptable in the context of production at industrial rates and, in the context of the present invention, allows a sufficient carbon dioxide loading level of the fraction in terms of quantity.

[0094] Advantageously, the pressure in the carbonization reactor 2 is substantially equal to atmospheric pressure. The apparatus 1 is therefore less hazardous, less complex and less expensive than a pressurized apparatus.

[0095] Advantageously, the fume comprises at least 5% by weight or volume of carbon dioxide.Such a fume is capable of achieving an effective carbon dioxide loading level in terms of quantity and rate.

Claims

1. A device (1) for the forced carbonization of a fine fraction of recycled concrete, comprising: a carbonization reactor (2) in which the fine fraction can and is intended to be brought into contact with a gas containing carbon dioxide, - first water spraying means (11) capable of increasing the moisture content of the fine fraction, and - regulating means (16) capable of managing the temperature and the relative humidity of the carbon dioxide-containing gas, The device comprises a computer control unit (6) capable of controlling the first spraying means (11) and the means (16) for regulating the gas containing carbon dioxide.

2. The device (1) according to claim 1, characterized in that The first spraying device (11) is arranged upstream of the carbonization reactor (2) according to the moving direction of the fine fraction, or is arranged inside the carbonization reactor (2) and located near the inlet of the fine fraction.

3. The device (1) according to any one of claims 1 or 2, characterized in that The apparatus comprises first means (7) for measuring the moisture content in the fine fraction, the first measuring means (7) being arranged upstream of the carbonization reactor (2) according to the direction of movement of the fine fraction.

4. The device (1) according to any one of the preceding claims, characterized in that The apparatus comprises second means (8) for measuring the relative humidity and / or the temperature of the gas in the carbonization reactor (2).

5. The device (1) according to claim 4, characterized in that The device comprises a circuit (60) for injecting a gas containing carbon dioxide in the carbonization reactor (2), the carbon dioxide-containing gas injection circuit (60) being fluidically connected to a supply source (14) of fumes originating from combustion.

6. The device (1) according to claim 5, characterized in that The carbon dioxide-containing gas injection circuit (60) comprises items arranged in the following order according to the flow direction of the carbon dioxide-containing gas: - an outlet dryer (13) intended to dry the carbonized fine fraction at the outlet of the carbonization reactor (2), a pneumatic separation device (17) capable of separating, on the one hand, the carbon dioxide-containing gas and, on the other hand, a carbonized and dried fine fraction, said separation device (17) comprising a first outlet (18) through which the carbonized and dried fine fraction is intended to be discharged, a volume distribution system (20) capable of managing the volume of the gas containing carbon dioxide sent towards the carbonization reactor (2), - means (16) for conditioning the gas containing carbon dioxide, said means being able to modify the relative humidity and / or the temperature of the gas containing carbon dioxide, - means (15) for injecting the gas containing carbon dioxide into the carbonization reactor (2).

7. A method for the forced carbonization of a fine fraction originating from recycled concrete, capable of implementing a device (1) according to any one of claims 1 or 2, comprising the following steps: - a step of adjusting the fine fraction so that said fine fraction has a predetermined moisture content substantially equal to a set point value, and - a step of conditioning the carbon dioxide containing gas such that the relative humidity and / or the temperature of said gas is substantially at a set point value, - a step of supplying said carbonization reactor (2) with a fine fraction originating from recycled concrete comprising hydrated cement paste, said fine fraction having a particle size less than or equal to 16 mm, said fine fraction having been previously conditioned during said step of conditioning the fine fraction, - a step of injecting said carbon dioxide-containing gas into said carbonization reactor (2), said gas having been previously conditioned during a gas conditioning step, - A step of carbonizing said fine fraction in said carbonization reactor (2).

8. A method according to claim 7, implementing an apparatus according to claim 3, comprising the step of measuring the moisture content in the fine fraction, comparing the measurement result with a set point value, in which method the amount of water injected upstream of the carbonization reactor is adjusted so that the moisture content in the fine fraction is substantially equal to the set point value.

9. The method according to any one of claims 7 or 8, implementing the apparatus according to claim 4, comprising the step of measuring the relative humidity and / or the temperature of the gas in the carbonization reactor, comparing each measurement result with a set point value, wherein during the step of regulating the gas, the relative humidity and / or the temperature of the carbon dioxide-containing gas is modified so that each of the relative humidity and / or the temperature in the carbonization reactor is substantially equal to the set point value.

10. Method according to any one of claims 7 to 9, implementing a device according to claim 6, comprising a step of drying the fine fraction at the outlet of the carbonization reactor by means of fumes originating from combustion, the fine fraction being dried after carbonization.

11. A method according to any one of claims 7 to 10, implementing a device according to any one of claims 5 or 6, in which the carbon dioxide injected into the carbonization reactor originates from fumes originating from combustion.

12. Method according to claims 7 to 11, comprising a pneumatic separation step by means of the pneumatic separation device (17), during which a dry and carbonized fine fraction is separated from the fumes.

13. Method according to any one of claims 7 to 12, implementing a device according to claim 6, wherein the method comprises the step of volumetric distribution in order to send a predetermined amount of carbon dioxide towards the gas regulating device (16).

14. The method according to any one of claims 7 to 13, characterized in that The temperature in the carbonization reactor (2) is between 30°C and 80°C, preferably 40°C.

15. The method according to any one of claims 7 to 14, characterized in that The relative humidity of the gas in the carbonization reactor is between 40% and 100%.

16. The method according to any one of claims 7 to 15, characterized in that The residence time of the fine fraction in the carbonization reactor is between 20 and 120 minutes.

17. The method according to any one of claims 7 to 16, characterized in that The pressure inside the carbonization reactor is substantially equal to atmospheric pressure.

18. The method according to any one of claims 7 to 17, characterized in that The particle size of the fine fraction is less than or equal to 6 mm.

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