OA19445A - Optimized thermolysis installation and implementation process. - Google Patents

Abstract

Installation (22) for thermolysis of waste comprising a first drying chamber (2) suitable for vacuum drying the incoming waste and a second calcination chamber (4) suitable for treating in vacuum calcination the dried waste from the first chamber ( 2), each enclosure comprising an external heating system comprising a combustion chamber (3,5), and a vacuum pump (15,16) making it possible to maintain the vacuum in said enclosure (2,4) and connected to said enclosure (2,4) via an extraction duct (13, 14). Said installation (22) being characterized in that it comprises a duct (14,12) for circulating gas from the second enclosure (4) to the second enclosure (4) through the heating system (5) via the 'exterior of the second enclosure (4). Thermolysis process for implementing the installation (22).

Description

The present invention relates to the general field of a thermolysis installation and a method of implementing this installation.

Thermolysis is the thermal treatment of waste in the absence of air. Thermolysis is, in fact, only one application, adapted to waste, of the traditional technique of making charcoal.

The thermal treatment of waste could be done by combustion but then in the presence of air. This poses the disadvantage that the still usable combustion gases (such as methane) are discharged with the fumes (CO2, N2), which reduces the profitability of the process.

The wastes to be treated are generally either organic chemicals (for example plastics, rubber, paints, etc.) or hydrocarbon compounds and / or natural products with a high proportion of carbon (for example wood, tissues, plants ...).

In most cases, the waste to be treated must be pretreated before the thermolysis treatment to improve thermolysis. This pretreatment consists in drying them, or even in grinding them in order to homogenize them. Most often, the waste to be treated is only dried.

In thermolysis, the waste is not burned, but heated in the absence of air in a sealed chamber at medium temperature (180 to 400 ° C), which produces calcination.

Rather traditionally, the enclosure is heated from the outside, in which case the enclosure is evacuated (depressed). Heat and the absence of air cause organic matter to decompose into two parts: a solid component and a hot gas.

The solid component is a carbonaceous residue which contains mineral matter which could not be decomposed by heat (ferrous and non-ferrous metals, glass, ceramics, gravel ...), and, above all, carbon. This carbonaceous residue leaves the oven at around 300-450 ° C, and must be cooled. Cooling can be done under nitrogen, in which case it is followed by washing. Preferably, this cooling can be carried out by washing with water, which advantageously makes it possible to capture part of the chlorine if necessary. Cooling is most often followed by a first sorting to remove the glass and inert materials (gravel, ceramics), then a possible second sorting to separate the ferrous and non-ferrous metals. Freed from part of the mineral matter (glass, gravel) and metals, the final residue consists only of carbon and resembles a coal.

Gas evolution occurs during thermolysis. This gas consists of a condensable fraction, that is to say which can be liquefied and therefore turn into oil (gasoline vapors, water vapors, etc.), and a non-condensable fraction, that is to say which remains in the gaseous state at the temperatures considered (hydrogen, methane, carbon monoxide, hydrocarbons, etc.). This oil can be used as fuel, for example in a combustion chamber. The gas which generally escapes from the top of the enclosure, mixed with the dust, can then be treated in a conventional manner: dusting then combustion. In general, this gas is burned first. This makes it possible to minimize its on-site storage. Indeed, this storage is most often problematic, because, in particular, it requires a certain storage capacity for these gases under pressure and it poses safety problems (because these gases are combustible).

A thermolysis installation therefore has, according to known techniques, the drawback of very high energy consumption due to heating, drying of the products to be treated, or even a dilution of the combustible products resulting from thermal decomposition with the combustion fumes. .

The invention relates to a thermolysis installation, overcoming the aforementioned drawbacks of prior art installations.

The subject of the invention is thus, in a first aspect, a waste thermolysis installation comprising at least two enclosures, namely a first drying enclosure and a second calcination enclosure, each of these two enclosures being able to operate under vacuum. , the first chamber being able to dry the incoming waste and the second chamber being able to process the dried waste from the first chamber by calcination, each of the two drying and calcination chambers comprising an external heating system comprising at least one at least one combustion chamber, and at least one vacuum pump making it possible to maintain the vacuum in said chamber and connected to said chamber by an extraction duct,

Said installation being characterized in that it comprises at least one gas circulation duct from the second enclosure to the second enclosure through the heating system from the outside of the second enclosure.

Advantageously according to the invention, the installation allows during its implementation a substantial saving in energy consumption and gas supply from the outside since it allows the use, for the second calcination chamber, of recycled gases, which are combustible gases, without the presence of air or of oxygen in the air, which makes it possible to keep the internal atmosphere of the enclosures in depression and without air. This recycling does not impoverish the calorific value of the combustible thermolysis gases since these gases have the same composition between the outlet of the enclosure and their recycling in the enclosure.

Advantageously, the two enclosures have differentiated functions and are independent, while operating in parallel, which significantly facilitates access for the maintenance of equipment of the rotating machine type.

According to the invention, it is not necessary to have a specific heating system on the circulation duct: the heating system of the second enclosure is advantageously used.

By "through" or "through" is meant according to the invention that there is no direct contact (and therefore no exchange of content) with the interior of the device.

According to a preferred embodiment, the gas circulation duct issuing from the second enclosure to the second enclosure comprises multiple outlet orifices in the second enclosure.

Advantageously, this makes it possible to promote the calcination or pyrolysis reaction which takes place in said second chamber.

According to one embodiment, the heating system can be supplied with boiler fumes, gas turbine fumes or steam turbine fumes.

The vacuum pump or pumps advantageously make it possible to generate a dynamic vacuum without interrupting the vacuum, without an airlock and without a transfer system. The vacuum pump can be common to the two enclosures.

Preferably, the gas circulation duct issuing from the second enclosure to the second enclosure passes through the combustion chamber of the second enclosure.

In this case, the installation advantageously allows recycling without cooling and without loss of flow: the fraction of gas from the second chamber is heated by the combustion chamber before joining the second chamber.

According to one embodiment, independent or not of the previous embodiment, the installation further comprises at least one gas circulation duct coming from (or extracted) from the second enclosure to the first enclosure, preferably through the gas flow system. heating of said first enclosure. Preferably, the gas circulation duct from the second enclosure to the first enclosure passes through the combustion chamber of the first enclosure.

According to one embodiment, whether or not independent of the previous embodiment (s), the installation further comprises at least one gas circulation duct coming from (or extracted) from the first enclosure to the first enclosure through the heating system. of said first enclosure. Preferably, the gas circulation duct from the first enclosure to the first enclosure passes through the combustion chamber of the first enclosure.

In all cases, the part of the gas circulation duct which passes through the combustion chamber is generally in the form of a coil, which makes it possible to increase the time of presence of the gas in said part of the duct and therefore to heat it, from so that, during the implementation of the installation, the temperature at their recycling in the enclosure is higher, generally at least 50 ° C., than the temperature in the enclosure. In addition, the gases recycled into the enclosure are generally at a pressure slightly above atmospheric pressure and are therefore drawn in by the vacuum prevailing in the enclosure.

The installation according to the invention may further comprise at least one duct for discharging part of the gases from the first enclosure and / or at least one duct for discharging part of the gases from the second enclosure . (By "A and / or B" is meant according to the invention "A, or B, or A and B").

This allows the proper functioning of the installation and in particular to ensure the material balances. In other words, during the implementation of the installation in thermolysis, the recycling of the gases from the two enclosures is generally not complete.

It should be noted in this regard that the presence of water vapor in the gases from the first chamber and recycled into it does not generally pose a problem for the operation of the first chamber. In fact, they are previously evacuated by passing through a cooling system (such as a scrubber) in which the condensation of the water allows the separation of the combustible gases which are recycled in the first chamber.

By "passage through a device" is meant according to the invention that there is no direct contact with the interior of the device.

The combustion chamber of the first enclosure generally comprises a burner supplied with fuel so as to produce heat. This fuel may include, preferably consist of, at least a condensed portion of gas issuing from the second enclosure. Usually, it is a condensed and hydrocarbon part of said gas.

The combustion chamber of the second enclosure generally comprises a burner supplied with fuel so as to produce heat. This fuel may include, preferably consist of, at least a portion of gas issuing from the second enclosure. Usually, it is a condensed and hydrocarbon part of said gas.

To this end, according to a variant of the invention, whether or not independent of the preceding embodiment (s), the installation further comprises a supply duct for at least one of the two combustion chambers via at least one duct. bypass connected, directly or indirectly, to the gas circulation duct from the second enclosure to the second enclosure.

It is also possible that the combustion chamber of the first enclosure does not include a burner. Indeed, the presence of a burner is not necessary in the combustion chamber of the first chamber if the hot gases from the second chamber are sufficient to heat the first chamber.

According to a variant of the invention, independent or not of the previous embodiment (s), the installation further comprises at least one communication duct between the combustion chamber of the first enclosure and the combustion chamber of the second enclosure. In this case, it is generally not necessary to turn on the burner of the combustion chamber of the first enclosure for the combustion chamber to fulfill its role as the heating system of the first enclosure.

According to a preferred embodiment of the invention, independent or not of the previous embodiment (s), the installation further comprises a third cooling chamber, able to operate under vacuum and able to cool the solid residues from the second. pregnant.

According to a preferred variant, the installation then further comprises an airlock for the introduction (or entry) of the waste entering the first enclosure and / or, preferably and, an exit airlock for the cooled solid residues from the third. enclosure, each of the airlock being connected to at least one vacuum pump. In the case of the presence of two locks, each of the locks is connected to the same vacuum pump.

Advantageously, this makes it possible to be able to use a single vacuum pump for each of the locks, the opening of the locks generally being done on an ad hoc basis and independently.

According to the invention, the three enclosures advantageously have differentiated functions and are independent, while operating in parallel, which significantly facilitates access for maintenance of rotating machine type equipment.

A subject of the invention is also, in a second aspect, a thermolysis process for implementing the installation according to the invention, said installation comprising at least two successive enclosures, namely a first drying enclosure and a second enclosure. calcination chamber, each of the two drying and calcining chambers comprising an external heating system comprising at least one combustion chamber, and at least one vacuum pump making it possible to maintain the vacuum in said chamber by extracting gas from the 'pregnant,

Said method being such that the incoming waste is introduced into the first drying chamber operating under vacuum and that the dried waste from the first chamber is introduced into the second calcination chamber operating under vacuum,

Said method being characterized in that it comprises at least one recycling of gas from the second enclosure to the second enclosure after heating through the heating system from the outside of the second enclosure.

According to the invention, there is no heating of the recycled gas in the second enclosure: the heating is advantageously carried out by the heating system of the second enclosure.

According to a preferred embodiment, the gas recycled into the second enclosure is reinjected into said enclosure at multiple locations in the second enclosure.

Advantageously, this makes it possible to promote the calcination or pyrolysis reaction which takes place in said second chamber.

Preferably, said heating is carried out by passing through the combustion chamber of said second enclosure.

In this case, the process advantageously allows recycling without cooling and without loss of flow: the fraction of recycled gas is reheated by the combustion chamber before joining the second enclosure.

Preferably, according to one embodiment of the invention, the gas from the second enclosure is recycled to the first enclosure, optionally after heating through the heating system from the outside of said first enclosure. Preferably, said heating is carried out by passing through the combustion chamber of the first enclosure.

In practice, the vacuum in the first enclosure is generally 0.3 to 0.5 bar (30 to 50 MPa). The vacuum in the first chamber allows the heated gas, at a pressure greater than atmospheric pressure at the outlet of the vacuum pump, to be sucked in by the vacuum prevailing in the chamber. To initiate drying, heating is started using gas stored in a tank before the process produces gas. It is also possible to use the recycling of the gases from the second chamber into the first chamber, which makes it possible to exceed 100 ° C. The temperature at the outlet of the first enclosure is between 100 and 120 ° C. By passing through a coil in the combustion chamber, the temperature of the gas to be recycled from the second chamber into the first chamber, when this recycling exists, can reach 300 ° C.

In practice, the vacuum in the second chamber is generally 0.3 to 0.5 bar (30 to 50 MPa). The vacuum in the second chamber allows the heated gas, at a pressure greater than atmospheric pressure at the outlet of the vacuum pump, to be drawn in by the vacuum prevailing in the chamber. To initiate calcination, a temperature of over 180 ° C is required in the second chamber. In operation, the temperature at the outlet of the second enclosure is between

250 and 400 ° C. By passing through a coil in the combustion chamber, the temperature of the gas to be recycled in the second chamber can reach 400 to 600 ° C.

According to one embodiment of the invention, independent or not of the previous embodiment, at least one recycling of gas from the first chamber to the first chamber is carried out after heating through the heating system from the outside of the chamber. the first enclosure. Preferably, said heating is carried out by passing through the combustion chamber of the first enclosure.

According to one embodiment of the invention, whether or not independent of the previous embodiment (s), at least one of the two combustion chambers of the first chamber and of the second chamber is supplied by at least one. part of the gases from the first chamber and / or from the second chamber, preferably from the second chamber. Preferably, said part of the gases is pretreated before feeding the combustion chamber (s). Such pretreatment can include treatment to remove water, for example condensation. Such pretreatment can include passage through a cooling system such as a scrubber.

But it is also possible to feed these combustion chambers with part of the flue gases from a fuel recovery boiler. Such a boiler, optionally present on the site hosting the thermolysis installation, is typically a steam boiler which generally operates from fuels (coal, oils and residual gas) resulting from the process and which can produce electricity. . It produces smoke at around 700 ° C, which can be used in combustion chambers.

According to one embodiment of the invention, independent or not of the previous embodiment (s), the solid residues from the second chamber are cooled in a third cooling chamber operating under vacuum. Preferably, said cooling is washing with water, generally carried out in a washer.

Advantageously, this makes it possible to prevent self-combustion of these solids during their release to the open air, before the introduction of these solids, generally at a temperature below 60 ° C, for their possible sorting. On the other hand, water, if used, helps to recover some of the pollutants, such as chlorine and / or heavy metals, which would be present in these solid residues.

The description of the invention will now be continued with the detailed description of an exemplary embodiment, given below by way of illustration and not by way of limitation, with reference to the accompanying drawing. On this one:

Figure 1 is a schematic sectional view of a thermolysis installation according to the invention.

FIG. 1 illustrates a waste thermolysis installation 22 comprising a first drying chamber 2 and a second calcining chamber 4. In this Figure, the fluid flow directions are indicated by arrows. Unless it is expressly stated that this is not the case, the fact that two conduits crossing each other in Figure 1 means that these conduits are connected.

The first chamber 2 is suitable for operating under vacuum and is suitable for drying the incoming waste, for their subsequent treatment by thermolysis in the calcination chamber 4. It comprises an external heating system consisting of a combustion chamber 3, comprising a burner 9, and a vacuum pump 15 making it possible to maintain the vacuum in said chamber 2 and connected to said chamber 2 by an extraction duct 13. This combustion chamber 3 comprises a wall forming a double envelope surrounding it. enclosure 2. According to the invention, the installation 22 comprises a circulation duct (13; 29; 11) consisting of the extraction duct 13 allowing passage through the vacuum pump 15, said duct 13 opening onto a duct 18 allowing gas to be evacuated, a duct 29 and a gas circulation duct 11 towards the first enclosure 2. The duct 11 passes through the heating system of said first enclosure 2, that is to say through the combustion chamber ion 3. The conduit 11 takes at this location a coil shape intended to extend the time of presence of the gas present in the conduit 11 within the combustion chamber 3. The gases which are not recycled into the first enclosure 2 are capable of being evacuated through the evacuation duct 18.

The second chamber 4 is suitable for operating under vacuum and is suitable for treating the dried waste from the first chamber 2 by calcination. It comprises an external heating system consisting of a combustion chamber 5, comprising a burner 10. , and a vacuum pump 16 making it possible to maintain the vacuum in said enclosure 4 and connected to said enclosure 4 by an extraction duct 14. This combustion chamber 5 comprises a wall forming a double envelope surrounding the enclosure 4. According to the invention, the installation 22 comprises a circulation duct (14, 12) consisting of the extraction duct 14 allowing passage through the vacuum pump 16, said duct 14 dividing into a duct 30 and a circulation duct 12 gas to the second enclosure 4. The duct 12 passes through the heating system of said second enclosure 4, that is to say through the combustion chamber 5. The duct 12 takes the shape of a coil intended to lengthen the t when the gas present in the duct 12 within the combustion chamber 5 is present. The gases which are not recycled into the second chamber 4 are liable to be evacuated through a duct 19 allowing the gases to be evacuated, the duct 19 being connected to the conduit 14 by the conduit 30 then a conduit 31.

According to the variant shown in Figure 1, the conduit 31 is divided into the conduit 19 and a conduit 26. The conduit 26 is divided into the conduits 27 and 28 (which is not connected to the conduits 11 and 13), respectively allowing to supply a part of the evacuated gases to the respective burners 9 and 10 of the respective combustion chambers 3 and 5. These gases usually undergo a pre-treatment (not shown), among others of condensation and removal of water, before being supplying the burners 9 and 10. During the operation of the installation 22, it is possible that only one of the burners 9 and 10 is supplied by at least part of the gas coming from the second chamber 4.

According to a variant not shown, it is also possible to provide a supply circuit to at least one of the burners 9 and 10 from the exhaust duct 18 connected to the first enclosure 2.

According to another variant, not shown, it is possible that the combustion chamber 3 does not include a burner 9, the combustion chamber 3 being only heated by the supply of gas from the second chamber 4.

According to the invention, the installation 22 further comprises a circulation duct (14, 30, 29, 11) of gas coming from the second enclosure 4 to the first enclosure 2 through the heating system, that is to say -to say of the combustion chamber 3, of said first enclosure 2. This circulation duct is formed by the duct 14, the duct 30 (which is divided into the duct 31 and a duct 29), the duct 29 and the duct 11.

The combustion fumes from the combustion chambers 3 and 5 are intended to be discharged through a chimney 8. According to the variant shown in Figure 1, the combustion chambers 3 and 5 are connected by a communication duct 25.

The installation 22 further comprises a third chamber 6 for cooling by washing with water, capable of operating under vacuum and capable of cooling the solid residues from the second chamber 4.

The cooling enclosure 6 is supplied by a cooling circuit 21, capable of using water, which opens out through a multitude of jets into the enclosure 6. The vacuum is maintained in the enclosure 6 by a vacuum pump. 17, which is able to evacuate the gases thus extracted through an evacuation duct 20. The water vapor is condensed and evacuated via an evacuation duct (not shown).

The installation 22 further comprises an inlet lock 1, consisting of two sub-parts 1a and 1b and three valves 101, 102 and 103. By the play of the movements of the valves 101, 102 and 103, the lock 1 can function. Initially, incoming waste (not shown) is introduced from outside the installation 22 into a first sub-part la of the airlock 1, at atmospheric pressure, by the opening of the valve 101, while the The other subpart 1b of the airlock 1 is isolated from the outside by closing the valve 103. The valve 102 is closed, isolating the enclosure 2 from the airlock 1. Secondly, the valve 101 is closed and the Waste is transferred to the second sub-part 1b of the airlock 1, under vacuum, by opening the valve 103. Finally, in a third step, the opening of the valve 102 allows the entry of the waste into the enclosure 2. In the case shown in Figure 1, the valves 101 and 102 are open and the valve 103 is closed.

The installation 22 further comprises an outlet airlock 7, consisting of two sub-parts 7a and 7b and three valves 71, 72 and 73. By the play of the movements of the valves 71, 72 and 73, the airlock 7 can operate. . Initially, cooled solid residues (not shown) left the enclosure 6 to a first sub-part 7a of the airlock 7, under vacuum, through the opening of the valve 72, while the other sub-part. part 7b of the airlock 7 is isolated from the enclosure 6 by closing the valve 73. The valve 71 is closed, isolating the airlock 7 from the outside. In a second step, the valve 72 is closed and the solid residues are transferred to the second sub-part 7b of the airlock 7, at atmospheric pressure, by opening the valve 73. Finally, in a third step, the opening of the valve. valve 71 allows the exit of residues outside the installation 22. In the case shown in Figure 1, the valves 71 and 72 are open and the valve 73 is closed.

A vacuum circuit 23 may be formed by a vacuum pump 24, connecting the locks 1 and 7. The gases extracted for maintaining the vacuum are evacuated by the vacuum pump 24.

The implementation, full or partial, of the installation 22 performs a thermolysis process according to the invention, as used in the two embodiments below. The installation makes it possible to implement different embodiments of the invention, as described above. In the examples, two embodiments are used, described below. These modes partly use the installation 22 described above, in particular as regards the recycling of the combustible gases from the second chamber 4, or even as regards the cooling of the solid residues from the second chamber 4.

According to this thermolysis process, incoming waste is introduced, via the airlock 1, into the first drying chamber 2, operating under vacuum, then the dried waste from the first chamber 2 is introduced into the second chamber 4, operating under vacuum. under vacuum. The solid residues from the second chamber 4 are then optionally introduced into the third chamber 6, operating under vacuum. Finally, the cooled solid residues are optionally extracted from enclosure 6 via airlock 7.

Gas from the second chamber 4 to the second chamber 4 is recycled via the ducts 14 and then 12, through the combustion chamber 5 of the second chamber 4.

Gas from the first chamber 2 to the first chamber 2 can be recycled via the conduits 13 then 11, through the combustion chamber 3 of the first chamber 2.

Gas from the second chamber 4 to the first chamber 2 can be recycled via the ducts 14 then 30 then 29 then 11, through the combustion chamber 3 of the first chamber 2.

The two combustion chambers 3 and 5 of the first chamber 2 and second chamber 4 are supplied with at least part of the gases from the second chamber 4, through the conduits 26, 27 and 28.

According to a first exemplary embodiment, three enclosures 2, 4 and 6 each have an internal diameter of approximately 2 m and a length of approximately 6 m. Installation 22 comprising the three enclosures has a treatment capacity of around 10,000 tonnes per year depending on the type of waste. The fumes 8 make it possible to operate an electrical unit of approximately 5 MW. From 5 to 15% of the fuels are used for the actual calcination process.

The operating conditions of the process are as follows:

the temperature in the drying chamber 2 is about 100 ° C;

the temperature of the calcination chamber 4 is about 180 to 400 ° C;

the temperature of the combustion gases in combustion chambers 3 and 5 is approximately 1200 ° C; and the temperature of the flue gases in chimney 8 is about 200 to 400 ° C.

In practice, 1000 kg of products to be treated, according to two different cases, were introduced into the first chamber 2 and give rise to:

either 300 kg and 240 kg of solids (coals), 130 kg of oils and 100 kg of gas if the products to be treated are household waste;

ie 30 kg and 280 kg of solids (coals), 380 kg of oils and 150 kg of gas in the case where the products to be treated are tires.

According to a second embodiment, 500 kg of products to be treated (household waste), at 30% humidity, were treated in two chambers, namely the drying chamber (first chamber) and the calcination chamber ( second enclosure). In fact, in this case, the cooling is carried out in the calcination chamber after the calcination.

The heating at start-up was carried out with make-up gas (gas network). The gases extracted by a liquid ring pump were maintained at about 100 ° C until the products were dry. After passing through the second chamber, the gas temperature rose to an average of 250 ° C after a heating period of 45 minutes. The extracted gas was used as fuel for the process. About 70 kg of oil, 120 kg of coal and 100 kg of inert materials including metals and minerals were recovered. In the absence of oxygen, the metals did not rust.

Claims (15)

1. Installation (22) for thermolysis of waste comprising at least two chambers (2,4), namely a first chamber (2) for drying and a second chamber (4) for calcination, each of these two chambers (2,4) ) being able to operate under vacuum, the first enclosure (2) being able to dry the incoming waste and the second enclosure (4) being able to process the dried waste from the first enclosure (2) by calcination, each of the two enclosures (2,4) drying and calcining comprising an external heating system comprising at least one combustion chamber (3,5), and at least one vacuum pump (15,16) making it possible to maintain the vacuum in said enclosure (2,4) and connected to said enclosure (2,4) by an extraction duct (13,14), Said installation (22) being characterized in that it comprises at least one gas circulation duct (14, 12) from the second enclosure (4) to the second enclosure (4) through the heating system (5) from the outside of the second enclosure (4). 2. Installation (22) for thermolysis according to claim 1, further comprising at least one circulation pipe (14,30,29,11) of gas from the second chamber (4) to the first chamber (2), from preferably through the heating system (3) from the outside of the first enclosure (2). 3. Installation (22) for thermolysis according to claim 2, wherein the circulation pipe (14,30,29,11) of gas from the second chamber (4) to the first chamber (2) passes through the combustion chamber (3) of the first enclosure (2). 4. Installation (22) for thermolysis according to any one of claims 1 or 2, wherein the circulation pipe (14,12) of gas from the second chamber (4) to the second chamber (4) passes through the chamber. combustion chamber (5) of the second chamber (4). 5. Installation (22) for thermolysis according to claim 4, further comprising at least one circulation pipe (13,11) of gas from the first chamber (2) to the first chamber (2), which pipe (13, 11) preferably passes through the combustion chamber (3) of the first enclosure (2). 6. Installation (22) according to any one of claims 1 to 5, further comprising at least one supply duct (27,28) of at least one of the two combustion chambers (3, 5) by at at least one bypass duct (30,31,26) connected to the gas circulation duct (14,12) from the second enclosure (4) to the second enclosure (4). 7. Installation (22) according to any one of claims 1 to 6, further comprising at least one communication duct (25) between the combustion chamber (3) of the first enclosure (2) and the combustion chamber ( 5) of the second enclosure (4). 8. Installation (22) for thermolysis according to any one of claims 1 to 7, further comprising a third chamber (6) for cooling, capable of operating under vacuum and capable of cooling the solid residues from the second chamber (4). ). 9. Installation (22) according to claim 8, further comprising an airlock (1) for introducing waste entering the first chamber (2) and / or an airlock (7) for discharging the cooled solid residues from the third. enclosure (6), each of the locks (1, 7) being connected to at least one vacuum pump (24). 10. A method of thermolysis implementation of the installation (22) according to one of claims 1 to 9, said installation (22) comprising at least two successive enclosures (2,4), namely a first enclosure (2). ) drying and a second chamber (4) for calcining, each of the two chambers (2,4) for drying and calcining comprising an external heating system comprising at least one combustion chamber (3,5), and at least one vacuum pump (15,16) making it possible to maintain the vacuum in said chamber by extracting gas from the chamber (2,4), Said method being such that the incoming waste is introduced into the first drying chamber (2) operating under vacuum and that the dried waste from the first chamber (2) is introduced into the second calcination chamber (4) operating under vacuum, Said method being characterized in that it comprises at least one recycling (14,12) of gas from the second chamber (4) to the second chamber (4) after heating through the heating system (5) by the exterior of the second enclosure (4), preferably carried out by passing through the combustion chamber (5) of said second enclosure (4). 11. A method of thermolysis according to any one of claims 10 or 11, wherein one proceeds to a recycling (30,29,11) of gas from the second chamber (4) to the first chamber (2), optionally after heating through the heating system (3) of said first enclosure (2). 12. Thermolysis process according to one of claims 10 or 11, such that said heating through the heating system (5) from outside the second enclosure (4) is carried out by passing through the combustion chamber (5). ) of said second enclosure (4). 13. A method of thermolysis according to any one of claims 10 to 12, wherein one proceeds to a supply (27,28) of at least one of the two combustion chambers (3, 5) of the first enclosure (2). ) and from the second enclosure (4) by at least part of the gases issuing from the first enclosure (2) and / or from the second enclosure (4). 14. The thermolysis process according to claim 13, wherein said part of the gases is pretreated before feeding the combustion chamber or chambers (3,5). 15. A thermolysis process according to any one of claims 10 to 14, wherein the solid residues from the second chamber (4) are cooled in a third cooling chamber (6) operating under vacuum.