Carbonization plant and process for producing charcoal

Abstract

The present invention relates to a carbonization plant for the production of charcoal from at least one lignocellulosic material. According to the invention, this plant comprises a vertical reactor (1) comprising a chamber inside which four superimposed treatment zones are delimited, the reactor defining a flow path between the two ends of said chamber, along which said at least one lignocellulosic material undergoes a carbonization process as they progress through the different zones, a first drying zone, placed at the upper end of said reactor, a second so-called torrefaction zone, a third so-called pyrolysis zone configured to carry out the pyrolysis of the material(s) originating from the so-called torrefaction zone, and a fourth so-called cooling zone for the charcoal produced,said reactor comprising a suction device for creating a vacuum in this chamber so as to evacuate the gases formed in the reactor through at least one so-called extraction opening and said reactor also comprising a reinjection opening, connected to a reinjection circuit for at least part of the gases formed in the reactor and evacuated through said at least one extraction opening, which is configured to lower the temperature of these gases to a coal extraction temperature. [Fig. 1],

Description

Title of the invention: Carbonization installation and method for producing charcoal Technical field

[0001] The present invention relates to a plant and a method for the continuous carbonization of one or more lignocellulosic materials to produce coal. Prior art

[0002] Vegetable charcoal, more commonly called biochar, is a solid residue rich in carbon.

[0003] Vegetable charcoal helps reduce CO2 present in the atmosphere by trapping it for several centuries depending on its quality.

[0004] Furthermore, biochar presents excellent opportunities as a soil amendment and stabilizer, particularly for organic farming.

[0005] It has a porous structure and microcavities that allow it to absorb water and nutrients.

[0006] However, there is an obstacle to the development of biochar which is linked to its relatively high production cost.

[0007] This high price is due to several factors including in particular the scale of the reactor, the cost of its maintenance, the required residence time of the material in the reactor and the energy efficiency of the process implemented.

[0008] We know of different processes for the production of charcoal.

[0009] These processes include a pyrolysis step during which three phases are formed, distinct by their temperatures and compositions: a solid phase (biochar), - a liquid phase (pyrolysis oil), - a combustible and non-combustible gaseous phase.

[0010] The proportion between these three phases depends essentially on the main operating parameters, in particular the temperature, the residence time and the heating rate.

[0011] It is noteworthy, however, that these state-of-the-art methods have numerous drawbacks.

[0012] First of all, it is difficult to use wet wood and prior drying of the wood, generally over relatively long periods, is a prerequisite to achieve a desired moisture content, typically less than 40% by weight.

[0013] This drying can be carried out for example in a dryer, which nevertheless requires significant energy expenditure.

[0014] Furthermore, the restricted dimensions of state-of-the-art furnaces make it necessary to pre-cut the lignocellulosic material(s).

[0015] Wood chips are thus typically used with the advantage of reducing the residence time in the reactor. This reduction is linked to a shorter heating time.

[0016] However, it is observed that the heat transfer in the hearth of the hearth is slow because this large volume of totally disordered material has low thermal conductivity and low permeability to gases.

[0017] It is therefore difficult to obtain a homogeneous distribution of carbonization temperatures in the reactor, which results in the formation of coal whose quality is inhomogeneous.

[0018] Furthermore, the gases resulting from pyrolysis are generally burned without any recovery of the liquid phase.

[0019] There is a pressing need for a carbonization plant for one or more lignocellulosic materials, the original design of which makes it possible to overcome the drawbacks set out above. Subject of the invention

[0020] The present invention aims at a continuous carbonization installation and method, simple in their design and in their operating mode, for the production of charcoal of excellent quality, responding to the drawbacks mentioned above.

[0021] Another object of the present invention is such a continuous carbonization installation making it possible to recover the liquid phase of pyrolysis.

[0022] Yet another object of the present invention is such a continuous carbonization installation allowing energy recovery (thermal and electrical) of the pyrolysis gases from the reactor.

[0023] Yet another object of the present invention is such a more environmentally friendly continuous carbonization plant and process. Disclosure of the invention

[0024] To this end, the invention relates to a continuous carbonization plant for the production of charcoal from one or more lignocellulosic materials. According to the invention, this carbonization plant comprises a vertical reactor comprising a chamber inside which four superimposed treatment zones are delimited, the reactor defining a flow path between the two ends of said chamber, along which said lignocellulosic material(s) undergo a carbonization process as they progress through the different zones, a first of these zones, called drying, placed at the upper end of said reactor comprising a drying device configured to bring the temperature of the lignocellulosic material(s) introduced into the reactor to a drying temperature, a second zone called the torrefaction zone being configured to carry out the torrefaction of the dried material(s) originating from the drying zone placed upstream, a third zone called the pyrolysis zone being configured to carry out the pyrolysis of the material(s) originating from the so-called torrefaction zone, and a fourth zone called the cooling zone for the coal produced, placed at the lower end of the vertical reactor, - said reactor comprising a suction device for creating a vacuum in said chamber so as to evacuate the gases formed in the reactor through at least one so-called extraction opening, placed at the upper end of the reactor, and - said reactor also comprising an opening at its lower end, called a reinjection opening, connected to a reinjection circuit for at least part of the gases formed in the reactor and evacuated through said at least one extraction opening, said reinjection circuit, external to the reactor, being configured to cool and lower the temperature of these gases to a temperature less than or equal to 70°C, preferably less than or equal to 50°C and even better less than or equal to 40°C, before their reinjection to participate in the cooling of the coal produced so as to bring the latter to a coal extraction temperature.

[0025] Advantageously, it is observed that the extraction temperature of the coal at the outlet of the vertical reactor is less than 70°C, even better, less than 50°C, and even more preferably between 30°C and 40°C, excluding spontaneous combustion of the coal produced in contact with the oxygen in the air.

[0026] Furthermore, it is noted that such a reactor makes it possible to obtain a coal whose non-volatile carbon content is at least 90% and whose mass fraction of water is between 2.5% and 5%.

[0027] The depression of the chamber makes it possible to prevent the release of gases potentially dangerous to the health of operators outside the vertical reactor.

[0028] Advantageously, the reactor of the present invention allows the treatment of lignocellulosic materials in the form of wood logs.

[0029] Preferably, these wooden logs have maximum dimensions: length of 25 cm and thickness of 10 cm, preferably a length of 20 cm and a thickness of 10 cm, and particularly advantageously, a length of 20 cm and a thickness of 8 cm.

[0030] The so-called cooling zone is configured to ensure natural cooling of the coal produced when it leaves the reactor. The reinjection of at least part of the gases formed in the reactor after the latter have been cooled on the reinjection circuit, not only accelerates the cooling of the coal produced in the reactor but also provides part of the heat requirements necessary for the pyrolysis stage.

[0031] This minimizes, or even avoids, the introduction of air (oxygen) likely to ignite the coal produced.

[0032] According to a particular embodiment of this carbonization installation, said reactor comprises an opening at its lower end, called a reinjection opening, placed in the peripheral wall of the reactor, and connected to a circuit for reinjection of at least a portion of the gases formed in the reactor after treatment, said reinjection circuit comprising a hot water supply installation comprising a thermodynamic circuit comprising one or more heat exchange condensers with a hot source for the transfer of heat to a hot water circuit, said hot source comprising a circuit in which at least a portion of the gases formed in the reactor and coming directly from the reactor circulate.

[0033] These gases formed in the reactor are essentially raw gases resulting from the pyrolysis of the dried lignocellulosic material(s) in the upper part of the reactor.

[0034] According to yet another particular embodiment of this carbonization installation, said reinjection circuit comprises at least one filtration device configured to purify said at least one part of the gases formed in the reactor as well as a fan to circulate said at least one part of the gases thus purified towards said reinjection opening so that it circulates in counter-current in the reactor.

[0035] According to yet another particular embodiment of this carbonization installation, said thermodynamic circuit comprising an evaporator exchanger associated with a cold source, said cold source comprises an air-cooling device provided with at least one fan. A hot water loop advantageously allows the thermal energy from the condenser(s) to be reused to meet the needs of a dryer. Advantageously, cooling the condenser(s) by a hot water loop with a dry cooler makes it possible to avoid using a water reserve. Indeed, this latter type of configuration involves additional operational constraints. One of the risks is health-related. Legionella growth in water is effective between 20°C and 50°C, with an optimal pH for growth of 6.9. An open-air water reserve therefore poses a risk of Legionnaires' disease. Another constraint lies in the use of a swimming pool, a source of environmental impact linked to significant water consumption. In a context where Many regions of France have to face long periods of drought during the year, the solution implemented in the present invention is more environmentally friendly.

[0036] According to yet another particular embodiment of this carbonization installation, said air-cooling device comprises a device for misting or projecting water droplets as well as a bacteriological disinfection device for disinfecting the liquid to be misted or projected in the form of droplets and thus avoiding any risk of bacteriological infection. It is known that misting water or projecting water droplets into the air improves the cooling of the heat transfer fluid to be cooled. The bacteriological disinfection device may comprise, for example, a source of ultraviolet rays configured to disinfect the water to be distributed, which is received in a treatment chamber before its distribution.

[0037] For example, this source of ultraviolet radiation may comprise point sources such as UV LEDs.

[0038] According to yet another particular embodiment of this carbonization installation, said reactor comprises one or more pressure measuring devices, said suction device comprising at least one variable speed fan connected to this or these measuring devices for regulating the pressure in the chamber.

[0039] According to yet another particular embodiment of this carbonization installation, it comprises a dryer for drying, in part, the lignocellulosic material(s) before their introduction into said reactor, a part of the hot water circuit passing through this dryer.

[0040] According to yet another particular embodiment of this carbonization installation, it comprises a dryer configured to dry the lignocellulosic material or materials so that they have a relative humidity of between 2% by weight and 25% by weight, preferably between 10% by weight and 15% by weight, and even more preferably equal to 15% by weight. This dryer may comprise at least one sensor for determining the humidity level of said lignocellulosic material or materials and sending an alarm when said level is measured to be less than or equal to a threshold value such as a value of 15% by weight.

[0041] According to yet another particular embodiment of this carbonization installation, said extraction opening is connected to a circuit for recovering a portion of said gases formed in said reactor, said recovery circuit comprising one or more heat exchange condensers with a hot source for transferring heat to a hot water circuit and an evaporator exchanger associated with a cold source, said hot source comprising a circuit in which circulates at least part of the gases formed in the reactor and coming directly from this reactor, said recovery circuit comprising means for recovering condensable liquid products such as oils or oil derivatives (esters) present in said at least part of the gases formed in the reactor. Preferably, the cold source comprises an air-cooling device provided with one or more fans.

[0042] The installation of the invention thus makes it possible to condense the liquid pyrolysis products with subsequent selection. The remaining part of the liquid pyrolysis products contains organic acids, alcohols, which are also extracted by other suitable extraction means.

[0043] According to yet another particular embodiment of this carbonization installation, said extraction opening is connected to a circuit for recovering a portion of said gases formed in said reactor after treatment, said recovery circuit comprising one or more gas engines such as one or more gas generator sets, and / or a combustion boiler for burning said at least a portion of said gases formed in said reactor. Preferably, this combustion boiler comprises an outlet port for the combustion gases formed in the boiler, which is connected to a heat recovery device. Preferably, the gas engine having an exhaust fume outlet port, this outlet port is also connected to a heat recovery device for recovering heat from the engine exhaust fumes. The energy from gas engine fumes, which come out at over 450°C, can thus be exploited. Depending on the temperature of the heat required, additional electrical recovery via an organic Rankine cycle (ORC) machine is possible.

[0044] For example, this heat recovery device may be a heat exchanger making it possible to supply heat energy to the dryer. Advantageously, this gas engine is connected to an alternator in order to produce electricity. For their part, the fumes resulting from the combustion of said at least one part of said gases formed in the reactor, can be sent to a heat recovery unit supplied with water, said heat recovery unit being configured to heat said water by recovering the heat from said fumes in order to produce steam and supply at least one steam turbine to produce electricity.

[0045] According to yet another particular embodiment of this carbonization installation, said recovery circuit comprises at least one filtration device configured to purify said at least part of the gases formed in the reactor and one or more condensers. Upstream of the gas engine, at least part of the gases formed in the reactor must be treated. In fact, it must comply with the following data: o The inlet pressure of the gas train must be between 120 mbar and 200 mbar,o The relative humidity must be less than or equal to 80%,o The temperature must be between 10°C and 40°C,o No tar is accepted by the machines, these must therefore be treated beforehand.

[0046] According to yet another particular embodiment of this carbonization installation, said reactor comprises an airlock for introducing the lignocellulosic material(s) and an airlock for discharging the coal produced, as well as a control device for alternately opening said airlocks. Such an airlock configuration allows the introduction of the lignocellulosic material(s) and the evacuation of the carbon produced without compromising the depression generated in the chamber. Preferably, this control device also comprises a sensor such as a level gauge for detecting a low level of material to be treated at the upper end of the reactor, said sensor emitting a level signal. In addition, the control device may control a lignocellulosic material supply device such as a container or a conveyor belt to automatically supply the upper end of the reactor based on the level signal output by the sensor.

[0047] According to yet another particular embodiment of this carbonization installation, said reactor comprises one or more openings, called injection openings, made in the peripheral wall of the reactor, each injection opening comprising a nozzle to ensure the supply of air into the coal combustion zone and a fan to circulate the air counter-current to the flow path.

[0048] The depression generated in the reactor being regulated, the supply or management of the air conditions the pyrolysis temperature. A controlled valve advantageously makes it possible to manage the air inlets to control the quantity of air entering the pyrolysis zone according to the quality of the coal to be produced.

[0049] According to yet another particular embodiment of this carbonization installation, the drying device is configured to bring the temperature of said lignocellulosic material(s) introduced into the reactor to a drying temperature of between 100°C and 200°C, and even better between 100°C and 120°C.

[0050] According to yet another particular embodiment of this carbonization installation, said roasting zone is configured to bring the temperature of said material(s) thus dried to a temperature between 200°C and 300°C, and even better between 200°C and 250°C.

[0051] According to yet another particular embodiment of this carbonization installation, this pyrolysis device is configured to bring the temperature of said material(s) coming from the so-called roasting zone to a temperature between 400°C and 800°C.

[0052] The present invention also relates to a method for the continuous carbonization of one or more lignocellulosic materials to form coal in which - said lignocellulosic material(s) is / are introduced into a vertical reactor comprising a chamber inside which superimposed treatment zones are delimited, the reactor defining a flow path between the two ends of said chamber, along which said lignocellulosic material(s) undergo a carbonization process as it progresses through the different zones, a first of said zones, called the drying zone, placed at the upper end of said reactor comprising a drying device configured to bring the temperature of the lignocellulosic material(s) introduced into the reactor to a drying temperature,a second zone called the roasting zone being configured to roast the dried material(s) from the drying zone placed upstream, a third zone called the pyrolysis zone being configured to pyrolyze the material(s) from the roasting zone, and a fourth zone called the cooling zone for the coal produced, placed at the lower end of the vertical reactor, - the pressure in the reactor is regulated to maintain said chamber under vacuum, - the gases formed in the reactor being evacuated through at least one extraction opening, said gases are recovered, their temperature is lowered to a temperature less than or equal to 70°C, preferably less than or equal to 50°C and even better less than or equal to 40°C, and they are reinjected into the lower part of said reactor to participate in the cooling of the coal produced so as to bring the latter to an extraction temperature.

[0053] A conditioning stage for the coal produced may be carried out at the reactor outlet, possibly preceded by a screening operation.

[0054] Advantageously, the temperature reduction is achieved by transferring heat from the hot gases from the reactor to a hot water circuit, said hot water circuit passing through a dryer to partially dry said lignocellulosic material(s) before their introduction into said reactor.

[0055] Preferably, the carbon content of the coal produced is analyzed and the depression generated in the reactor and / or the pyrolysis temperature is adjusted as a function of the carbon content of the coal produced.

[0056] Preferably, one or more lignocellulosic materials in the form of wooden logs having maximum dimensions, length of the order of 25 cm and thickness of the order of 10 cm, preferably a length of the order of 20 cm and a thickness of the order of 10 cm and whose humidity is equal to 15% maximum by weight, preferably between 10% by weight and 15% by weight, are introduced into said reactor. Brief description of the drawings

[0057] Other advantages, aims and particular characteristics of the present invention will emerge from the description which follows, given, for explanatory and in no way limiting purposes, with reference to the appended drawings, in which:

[0058] [Fig.l]

[0059] [Fig.l] is a front perspective view of an installation for carbonizing a load of wood according to a particular embodiment of the present invention, this view showing the circuit for re-injecting part of the gases formed in the reactor of the installation;

[0060] [Fig.2]

[0061] [Fig.2] is a rear perspective view of the carbonization plant of the [Fig.l] showing the recovery circuit for part of the gases formed in the reactor of the installation;

[0062] [Fig.3]

[0063] [Fig.3] is a schematic representation of a carbonization plant of a wood load according to another particular embodiment of the present invention, which shows the reinjection circuit of part of the gases from the vertical reactor as well as the hot water circuit supplying a dryer;

[0064] [Fig.4]

[0065] [Fig.4] is a schematic representation of an advantageous embodiment of the downstream part of the carbonization installation of [Fig.3] showing a part of the recovery circuit in which the treated gases feed a gas engine; Description of the embodiments

[0066] The drawings and the description below contain, for the most part, elements of a certain character. They may therefore not only serve to better understand the present invention, but also contribute to its definition, if necessary.

[0067] First of all, we note that the figures are not to scale.

[0068] In the following description, the terms "upper", "lower" and "lateral" are used with reference to the vertical physical orientation of the reactor of the invention when the latter is placed on a horizontal plane support. The terms "inlet", "outlet", "upstream" and "downstream" are used with reference to the direction of flow of the lignocellulosic material(s) in the vertical reactor of the invention, which is from top to bottom.

[0069] Figures 1 and 2 schematically represent an installation for carbonizing one or more lignocellulosic materials for the production of charcoal according to a particular embodiment of the present invention.

[0070] This carbonization installation comprises a reactor 1 fed by a line with a solid load consisting of one or more lignocellulosic materials.

[0071] It also includes a control station 2 and a hydraulic power station 3.

[0072] The vertical reactor 1 includes a chamber inside which four superimposed treatment zones are delimited, the reactor defining a flow path between the two opposite ends of this chamber, along which this charge undergoes a carbonization process as it progresses through the different zones of the reactor.

[0073] The first so-called drying zone is placed at the upper end of this vertical reactor 1 and comprises a drying device (not shown) configured to bring the temperature of the lignocellulosic material(s) introduced at the inlet of the reactor 1 to a drying temperature.

[0074] This drying temperature can be between 100°C and 200°C and more particularly between 100°C and 120°C.

[0075] The second zone, called the roasting zone, comprises a roasting device configured to roast the dried material(s) from the drying zone located upstream.

[0076] This roasting device can thus be configured to bring the temperature of said material(s) thus dried to a temperature between 200°C and 300°C and more preferably between 200°C and 250°C.

[0077] A third zone, called the pyrolysis zone, comprises a pyrolysis device configured to carry out the pyrolysis of the material(s) coming from the roasting zone.

[0078] This pyrolysis device can thus be configured to raise the temperature of said material(s) coming from the so-called torrefaction zone to a temperature between 400°C and 800°C.

[0079] A fourth zone called the cooling zone for the produced coal, placed at the lower end of the vertical reactor 1, ensures the cooling of the produced coal so that it leaves the reactor at an extraction temperature.

[0080] This reactor comprises a suction device for creating a vacuum in the chamber so as to evacuate the gases formed in the reactor through a so-called extraction opening, placed at the upper end of the reactor.

[0081] The charge introduced into this reactor can be treated prior to its introduction so as to bring it into line with the specifications of the reactor, such as its maximum dimensions or its humidity.

[0082] In particular, these specifications provide for the use of a feedstock with a humidity which must be reduced to a maximum of 15% by weight, preferably between 10% by weight and 15% by weight, because the humidity level of the feedstock has an influence on the efficiency of the reactor.

[0083] They also provide for the treatment of wooden logs having maximum dimensions, length of 25 cm and thickness of 10 cm, preferably a length of 20 cm and a thickness of 10 cm.

[0084] Preferably, each lignocellulosic material may be chosen from the group comprising hardwood such as oak, beech, hornbeam, ash, etc., coniferous wood such as pine, spruce, Douglas fir, etc. or recycled wood and mixtures of these woods.

[0085] The dried wood, the logs, is fed by a loading skip into the upper part of the reactor. The upper part of the reactor is equipped with two loading doors: a swing door and a guillotine door, this door system defining between these doors an airlock for introducing the lignocellulosic material(s).

[0086] The loading level is controlled by a level indicator placed in the upper part of the reactor.

[0087] Once the charcoal has cooled, it is discharged through a door system comprising a guillotine door and a swing door, this door system defining a coal discharge airlock between these doors.

[0088] The charcoal thus unloaded is conveyed by a conveyor belt 4 to a screening unit 5 before being packaged, for example, in a coal container 6.

[0089] This reactor also has an opening at its lower end, called a reinjection opening, placed in the peripheral wall of the reactor, and connected to a reinjection circuit 11-13 of at least part of the gases formed in the reactor after treatment.

[0090] These gases formed in the reactor exit through the so-called extraction opening at a temperature of approximately 600°C.

[0091] The reinjection circuit comprises a hot water supply installation comprising a thermodynamic circuit comprising three exchange condensers 11 heat exchanger with a hot source for heat transfer to a hot water circuit, as well as an evaporator exchanger associated with a cold source.

[0092] This hot source comprises a circuit in which at least part of the gases formed in the reactor and coming directly from the reactor circulate.

[0093] The hot water circuit is a circuit in which cooled water circulates upstream of these condensers 11, this water being heated during the heat transfer in order to provide calories at a point of use, here a dryer (not shown) for drying the lignocellulosic material(s) before their introduction into the reactor 1.

[0094] The cold source comprises for its part an air-cooling device provided with several fans capable of circulating ambient air between tubes in which a fluid to be cooled circulates.

[0095] This air-cooling device, known per se, comprises a heat exchanger formed of bundles of tubes. These tubes are arranged parallel to each other, and for example superimposed so as to form two walls of a V shape. Thus, each wall forms a bundle for circulation of the fluid to be cooled provided with an inlet for the fluid to be cooled and an outlet for the cooled fluid. The air-cooling device comprises a pump (not shown) ensuring the circulation of the fluid between the inlets and the outlets. The air-cooling device further comprises a temperature sensor capable of measuring the temperature of the fluid at the outlet.

[0096] This reinjection circuit also comprises a filtration device 13 configured to purify said part of the gases formed in the reactor 1 as well as a fan 12 to circulate said part of the gases thus purified towards said reinjection opening.

[0097] The installation also includes a tank 15 for recovering heavy and light oils as well as condensation liquids and a buried water tank 16.

[0098] Very advantageously, the extraction opening for the gases formed in the reactor is also connected to a circuit for recovering part of these gases not sent to the reinjection circuit.

[0099] This recovery circuit comprises a set of four heat exchange condensers 7 with a hot source for transferring heat to a hot water circuit and an evaporator exchanger associated with a cold source.

[0100] This hot source here comprises a circuit in which circulates a part of the gases formed in the reactor, and coming directly from this reactor 1.

[0101] Each of these heat exchange condensers 7 which are placed in series, is configured to separate a family of solid, liquid or condensable by-products present in the hot gases. The separation of tars on the one hand, of oils on the other hand, but also of aqueous products is thus obtained.

[0102] These by-products thus recovered can be recycled.

[0103] This recovery circuit also includes a metal fan 8 to ensure the circulation of the gases, a cyclone 9 and a burner 10.

Claims

1.

2. Claims Carbonization plant for the production of charcoal from one or more lignocellulosic materials, characterized in that it comprises a vertical reactor (1) comprising a chamber inside which are delimited superimposed treatment zones, the reactor defining a flow path between the two ends of said chamber, along which said lignocellulosic material(s) undergo a carbonization process as they progress through the different zones, a first of said zones, called the drying zone, placed at the upper end of said reactor comprising a drying device configured to bring the temperature of the lignocellulosic material(s) introduced into the reactor to a drying temperature, a second zone called the roasting zone being configured to roast the dried material(s) from the drying zone placed upstream,a third zone called pyrolysis zone being configured to carry out the pyrolysis of the material(s) coming from the zone called torrefaction zone, and a fourth zone called cooling of the coal produced, placed at the lower end of the vertical reactor (1), - said reactor comprising a suction device to create a depression in said chamber so as to evacuate the gases formed in the reactor through at least one opening called extraction, placed at the upper end of the reactor, and - said reactor also comprising an opening at its lower end, called reinjection opening, connected to a circuit for reinjection of at least part of the gases formed in the reactor and evacuated through said at least one extraction opening, said reinjection circuit being configured to cool and lower the temperature of these gases to a temperature less than or equal to 70°C,preferably less than or equal to 50°C and even better less than or equal to 40°C, before their reinjection to participate in the cooling of the coal produced to an extraction temperature., Carbonization installation according to claim 1, characterized in that said reinjection circuit comprises a hot water supply installation comprising a thermodynamic circuit comprising one or more heat exchange condensers (11) with a hot source for transferring heat to a hot water circuit, said hot source comprising a circuit in which at least part of the gases formed in the reactor and coming directly from the reactor circulate.

3. Carbonization installation according to claim 1 or 2, characterized in that said reinjection circuit also comprises at least one filtration device (13) configured to purify said at least one part of the gases formed in the reactor (1) as well as a fan (12) to circulate said at least one part of the gases thus purified towards said reinjection opening.

4. Installation according to any one of claims 1 to 3, characterized in that said thermodynamic circuit comprising an evaporator exchanger associated with a cold source, said cold source comprises an air-cooling device provided with at least one fan.

5. Carbonization installation according to claim 4, characterized in that said air-cooling device comprises a device for misting or projecting water droplets as well as a bacteriological disinfection device for disinfecting the liquid to be misted or projected in the form of droplets.

6. Carbonization installation according to any one of the preceding claims, characterized in that said reactor comprises one or more pressure measuring devices, said suction device comprising at least one variable speed fan connected to this or these measuring devices for regulating the pressure in the chamber.

7. Carbonization installation according to any one of the preceding claims, characterized in that it comprises a dryer for partially drying the lignocellulosic material(s) before their introduction into said reactor, a part of said hot water circuit passing through said dryer.

8. Carbonization installation according to any one of the preceding claims, characterized in that said extraction opening is also connected to a circuit for recovering a portion of said gases formed in said reactor, said recovery circuit comprising one or more condensers (7) for heat exchange with a hot source for the transfer of heat to a hot water circuit and an evaporator exchanger associated with a cold source, said hot source comprising a circuit in which circulates a portion of the gases formed in the reactor, and coming directly from this reactor, said recovery circuit comprising means for recovering the condensable liquid products present in said at least a portion of the gases formed in the reactor.

9. Carbonization installation according to any one of the preceding claims, characterized in that said extraction opening is connected to a circuit for recovering a portion of said gases formed in said reactor after treatment, said recovery circuit comprising: - a gas engine such as a gas generator set, or - a combustion boiler (10) for burning said at least a portion of said gases formed in said reactor, said combustion boiler (10) comprising an outlet port for the combustion gases formed in the boiler, which is connected to a heat recovery device.

10. Carbonization installation according to claim 8 or 9, characterized in that said recovery circuit comprises at least one filtration device (9) configured to purify said at least part of the gases formed in the reactor and one or more condensers.

11. Carbonization installation according to any one of the preceding claims, characterized in that said reactor comprises an airlock for introducing the lignocellulosic material(s) and an airlock for discharging the coal produced, as well as a control device for alternately opening said airlocks.

12. A method for the continuous carbonization of one or more lignocellulosic materials to form coal, in which - said lignocellulosic material(s) is / are introduced into a vertical reactor (1) comprising a chamber inside which superimposed treatment zones are delimited, the reactor defining a flow path between the two ends of said chamber, along which said lignocellulosic material(s) undergo a carbonization process as they progress through the different zones, a first of said zones, called the drying zone, placed atthe upper end of said reactor comprising a drying device configured to bring the temperature of the lignocellulosic material(s) introduced into the reactor to a drying temperature, a second zone called the torrefaction zone being configured to carry out the torrefaction of the dried material(s) originating from the drying zone placed upstream, a third zone called the pyrolysis zone being configured to carry out the pyrolysis of the material(s) originating from the torrefaction zone, and a fourth zone called the cooling zone for the coal produced, placed at the lower end of the vertical reactor (1), - the pressure in the reactor is regulated to maintain said chamber under vacuum, - the gases formed in the reactor being evacuated through at least one extraction opening, said gases are recovered, their temperature is lowered to a temperature less than or equal to 70°C, preferably less than or equal to 50°C and even better less than or equal to 40°C,and they are reinjected into the lower part of said reactor to participate in the cooling of the coal produced so as to bring the latter to an extraction temperature.

13. Carbonization process according to claim 12, characterized in that the temperature reduction is achieved by heat transfer from the hot gases from the reactor to a hot water circuit, said hot water circuit passing through a dryer to partially dry said lignocellulosic material(s) before their introduction into said reactor.

14. Carbonization process according to claim 12 or 13, characterized in that the carbon content of the coal produced is analyzed and the depression generated in the reactor and / or the pyrolysis temperature is adjusted as a function of the carbon content of the coal produced.

15. Carbonization process according to any one of claims 12 to 14, characterized in that one or more lignocellulosic materials are introduced into said reactor in the form of wooden logs having maximum dimensions, length of the order of 25 cm and thickness of the order of 10 cm, preferably a length of the order of 20 cm and a thickness of the order of 10 cm and whose humidity is equal to 15% maximum by weight, preferably between 10% by weight and 15% by weight.

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