WO2011157913A1

WO2011157913A1 - Flue-gas production and treatment plant

Info

Publication number: WO2011157913A1
Application number: PCT/FR2011/051020
Authority: WO
Inventors: Philippe Rousseau; José COUSSEAU
Original assignee: Philippe Rousseau; Cousseau Jose
Priority date: 2010-06-14
Filing date: 2011-05-05
Publication date: 2011-12-22
Also published as: FR2961291A1; FR2961291B1

Abstract

Flue-gas production and treatment plant, of the type comprising at least: a flue-gas generator (1) in the form of a boiler, the combustion hearth of which is called the hot zone; a space (5) for confinement of the flue gas produced by said flue-gas generator (1), this flue-gas confinement space (5), fed into the inlet thereof by the flue-gas generator (1) provided with a flue-gas discharge outlet (103), being connected, at the outlet thereof, to the combustion chamber of said flue-gas generator (1) by what is called a recirculation line (7), in order to recirculate the flue gas into said flue-gas generator (1); and a flue-gas treatment unit (4) placed in the flue-gas circulation line between the flue-gas discharge outlet (1A) of the flue-gas generator (1) and the outlet (6) of the confinement space (5) that feeds the recirculation line (7). The flue-gas recirculation line (7) runs into the hot zone of the flue-gas generator (1).

Description

FACILITY FOR THE PRODUCTION AND TREATMENT OF SMOKE

The present invention relates to a plant for the production and treatment of fumes.

It relates more particularly to an installation of the type comprising:

a smoke generator comprising at least one boiler equipped, if necessary, with a burner, said boiler comprising a combustion chamber equipped with at least one air inlet, a fuel supply inlet, a a smoke outlet, and a location suitable for being occupied by the fuel and / or a location reserved for the burner flame when the burner is present, the location or locations forming the combustion chamber being called (s) the hot zone of the smoke generator,

at least one smoke confinement space produced by said smoke generator, this smoke confinement space, connectable at the inlet to the flue gas exhaust outlet of the smoke generator, being connected to the output of the fu generator. driven by a circu it called recirculation, for a recirculation of the fumes inside said fumes generator,

a flue gas treatment unit disposed on the flue gas circulation circuit between the flue gas exhaust outlet of the flue gas generator and the outlet of the confinement space supplying the recirculation circuit, so as to be powered by at least a portion of the fumes flowing between the flue gas exhaust outlet of the flue gas generator and the outlet of the confinement space supplying the recirculation circuit.

Generally, the fumes produced by the boilers are released into the atmosphere. These fumes may contain toxic and polluting materials unfavorable to the environment in which they are rejected.

There are some facilities that attempt to recover at least some of the exhaust gas still called fumes for recycling. This is the case of the installations described in patents DE-10 2009 0261 19 and FR-2.291.454. In patent FR-2 291 454, the purified gases are fed to the main air inlet at the base of the boiler block to form a mixed fresh air / clean gas stream reinjected into the combustion chamber of the boiler. However, there is a rapid fouling of the boiler resulting from the supply of the latter in a mixed air. In DE 10 2009 0261 19, combustion residues, namely gases, dusts and fumes are cooled to form a liquid or solid residue fed into the fuel receiving vessel feeding the combustion chamber of the installation. The fuel residue is therefore mixed with non-recycled fuel to form a mixed fuel supplying the combustion chamber of the boiler. Again, it is found, because of the use of a mixed fuel for the supply of the fuel burner, a rapid fouling and saturation of the burner forcing a major maintenance. In addition, it is necessary to liquefy or solidify by cooling the combustion residues before reuse.

An object of the present invention is therefore to propose a plant for the production and treatment of fumes whose design makes it possible to reduce or even eliminate the quantity of fumes discharged into the atmosphere without harming the maintenance of the installation.

Another object of the present invention is to provide a plant for the production and treatment of fumes whose design allows to efficiently recycle fumes without increasing the fouling of the burner and / or the combustion chamber.

For this purpose, the subject of the invention is a plant for the production and treatment of fumes, of the type comprising at least:

a fume generator comprising at least one boiler equipped, if necessary, with a burner, said boiler comprising a combustion chamber; equipped with at least one air inlet, a fuel supply inlet, a flue gas outlet, and a location suitable for being occupied by the fuel and / or space reserved for the burner flame when the latter is present, this or these locations forming the or a combustion chamber hearth being called (s) the hot zone of the smoke generator,

at least one smoke confinement space produced by said smoke generator, this smoke confinement space, connectable at the inlet to the flue gas exhaust outlet of the smoke generator, being connected at the output to said smoke generator by a said recirculation circuit, for a recirculation of the fumes inside said fumes generator,

a flue gas treatment unit disposed on the flue gas circulation circuit between the flue gas exhaust outlet of the flue gas generator and the outlet of the confinement space supplying the recirculation circuit, so as to be powered by at least a portion of the fumes circulating between the smoke outlet of the smoke generator and the outlet of the confinement space supplying the recirculation circuit,

characterized in that the flue recirculation circuit, connected at the outlet to the combustion chamber of said flue gas generator, opens into the hot zone of the flue gas generator, this outlet of the flue recirculation circuit in the hot zone of the generator of fumes being distinct from the air inlets and fuel supply of the combustion chamber.

Thanks to the design of the combustion chamber which has a so-called fresh air inlet and a fuel supply inlet in the combustion chamber of the boiler of the smoke generator distinct from the outlet of the recirculation circuit of the fumes in the combustion chamber, there is no risk of saturation of the "fresh" air or fuel by said fumes. It should be noted that the air inlet of the combustion chamber may be common with, or separate from, the fuel supply inlet of said combustion chamber. As the flue gas recirculation circuit, connected at the inlet to the smoke confinement space, in particular at the outlet of the flue gases equipping said confinement space, and at the outlet to the combustion chamber of the boiler of the flue gas generator, opens in the hot zone of the smoke generator, the fumes undergo combustion which tends to be as total as possible.

Preferably, the outlet of the flue gas recirculation circuit in the hot zone of the flue gas generator is disposed downstream of the air inlet in the combustion chamber taken in the flue gas circulation direction inside said chamber. of combustion.

In other words, the outlet of the flue gas recirculation circuit in the combustion chamber opens into said combustion chamber between the outlet of the air inlet in said chamber and the flue gas outlet of said chamber taken. in the direction of circulation of the air and / or fumes in said chamber.

In the embodiment where the boiler is equipped with a burner, the hot zone of the flue gas generator corresponding to the location of the burner flame is delimited by means of a duct of the nozzle type having a peripheral wall. tubular surrounding the burner flame location and adapted to be occupied by said flame, this wall being provided with a through opening connected to the flue gas recirculation circuit and forming the outlet of said flue gas recirculation circuit in the hot zone of the smoke generator.

The fuel generally in the form of an air / fuel mixture is injected into the combustion chamber where it is ignited to form the flame of said burner and the flue gas recirculation outlet directly brings the flue gas into said flame without the fumes are mixed with the air / fuel mixture before ignition of said mixture. The fumes supplied directly into the flame of the burner undergo perfect combustion and do not interfere with the operation of the burner which is supplied with fresh air and fuel.

The presence of the nozzle promotes and facilitates this reintroduction of fumes directly at the flame of the burner.

In the embodiment where the boiler is a solid fuel boiler, the boiler comprises, at the level of its location suitable for being occupied by the fuel, a perforated fuel support, such as a grate, the inlet of air in the combustion chamber opens below said fuel carrier and the flue gas recirculation circuit opens into the combustion chamber above said fuel carrier.

This configuration makes it possible, for the same reasons as mentioned above, to ensure perfect combustion of the fumes fed into the combustion chamber directly at the level of the hot zone of the hearth, in the combustion zone of the solid fuel.

In the embodiment where the boiler is equipped with a burner, the burner has a predetermined air register, by construction, the maximum air supply flow of said burner expressed in m ³ / h, and the volume of the burner. the confinement space expressed in m ³ is equal to at least 10 times the maximum air supply flow rate of said burner expressed in m ³ / h. In other words, preferably, the volume of the confinement space expressed in m ³ is equal to at least 10 times the air supply volume of the burner over a period of one hour for a control flow adjustment. air supply maximum of said burner.

Thus, for example, if the maximum burner air supply flow rate is 5 m ³ / h, the volume of the confinement space is chosen to be at least equal to 50 m ³ .

A flue gas recirculation can therefore be organized in a safe manner excluding the presence of chimneys according to the state of the art. Preferably, the processing unit comprises at least:

a reactor at least partially filled with reagents at least one of which is selected from the group of reagents formed by lime, activated carbon, granular urea and

- a filter.

In a first embodiment of the invention, the treatment unit is arranged in line with the smoke generator and is interposed between the smoke generator and the smoke confinement space. In a second embodiment of the invention, the treatment unit is disposed on a plug-off branch of the fluid circulation circuit portion extending from the flue gas outlet of the smoke generator up to at the exit of the confinement space supplying the recirculation circuit. The bypass branch is connected to the entry to the confinement space and opens, after passing through the treatment unit, to the open air.

Preferably, the installation also comprises means for analyzing the flue gas flowing inside the installation, said flue gas analysis means being able to emit signals, in particular electrical signals, function of the result of the analysis. The presence of these means for analyzing flue gases makes it possible, in the event of saturation of the installation, either to evacuate after treatment a portion of the flue gases to the outside of the installation, or to stop the installation, in particular the burner of the installation or reduce the air supply rate of said burner.

In particular, the air inlet of the combustion chamber of the flue gas generator and / or the outlet of the flue gas recirculation circuit in the hot zone of the flue gas generator are equipped with shutter means configured to be flown from signals provided by the flue gas analysis means.

Preferably, the smoke confinement space is delimited by means of a hollow structure whose interior volume is compartmentalized by means of baffles.

The subject of the invention is also a process for the production and treatment of fumes using a plant for producing and treating fumes of the aforementioned type, said process comprising:

at least one step for producing the fumes inside the combustion chamber of the boiler of said installation,

a step of confining the smoke discharged from the combustion chamber of the boiler through the smoke outlet of said combustion chamber in a confinement space of said installation, a step of supplying the smoke of the space for confining the flue gases in the combustion chamber of the boiler by a flue gas recirculation circuit,

a step of treatment of the fumes by means of a treatment unit able to be supplied with at least a part of the fumes flowing between the flue gas exhaust outlet of the flue gas generator and the exit of the confinement space feeding the recirculation circuit,

characterized in that the fumes are brought into the combustion chamber of the boiler of the flue gas generator by means of the flue gas recirculation circuit opening directly into the hot zone of the flue gas generator, and by supplying the combustion chamber of the boiler with air and fuel at the flue gas generator. using at least one air inlet and a fuel inlet separate from the outlet of the flue gas recirculation circuit in said combustion chamber.

The invention will be better understood on reading the following description of exemplary embodiments, with reference to the accompanying drawings, in which: FIG. 1 represents a schematic view of a first embodiment of an installation with a burner boiler according to to the invention; FIG. 2 is a diagrammatic view of a second embodiment of an installation with boiler with burner according to the invention; FIG. 3 represents a detailed view of the inlet of the flue gas recirculation duct in the burner, and FIG. 4 represents a very schematic view of a third embodiment of a solid fuel boiler installation according to FIG. invention.

As mentioned above, the production and flue gas treatment plant, object of the invention, comprises at least:

a generator 1 of fumes

at least one space 5 for confining the fumes

and a unit 4 for treating the fumes.

The smoke generator 1 comprises at least one equipped boiler, if necessary, a burner 2, said boiler having a combustion chamber 100 equipped with at least one air inlet 1 01, a fuel supply inlet 1 02, a discharge outlet 103 of smoke, and a location 104 suitable for being occupied by the fuel and / or a location 1 05 reserved for the flame of the burner 2 when the latter is present, this or these locations 1 04, 1 05 forming the or a combustion chamber combustion chamber 100 being called (s) the hot zone of the smoke generator 1. The boiler may be an incinerator boiler, a domestic boiler, a boat boiler, a cement plant boiler, a refinery boiler or any other industrial or domestic boiler.

In the example shown in FIGS. 1 and 2, the boiler is equipped with a burner 2. The burner makes it possible, in itself known manner, to inject a flammable air / fuel mixture into the combustion chamber of the combustion chamber. Boiler. This air and this fuel are injected into the combustion chamber at the head, in particular the nozzle of the burner, these injection zones forming the air inlets 101 and 102 for supplying fuel to the combustion chamber. In other words, the air inlet 101 and the fuel injection port 102 of the combustion chamber form the injection inlets of the air / fuel mixture of the burner inside the combustion chamber of the generator 1 of smoke when the smoke generator is equipped with a burner boiler.

In the example shown in FIG. 4, the boiler is a solid fuel boiler without a burner, that is to say, in the sense of the patent of an apparatus intended to introduce, into a combustion chamber. Boil the air / fuel mixture and ignite it to produce a flame called the burner flame. In the example shown in Figure 4, the inlet 102 of solid fuel supply of the boiler has not been shown. This boiler comprises, at its location 104 suitable for being occupied by the fuel, a perforated fuel support 15, such as a grid.

Said installation also comprises at least one space 5 for confining the smoke produced by the generator head of smoke. This flue gas containment space 5 is supplied at the input by the smoke generator 1 equipped for this purpose with an outlet 103 for evacuating the flue gases. This flue gas containment space 5 is connected at the outlet to the combustion chamber of the flue gas generator 1 by a recirculating circulation circuit 7, for flue gas recirculation inside the flue gas generator 1.

The installation also comprises a flue gas treatment unit 4 disposed on the flue gas circulation circuit between the smoke evacuation outlet 103 of the flue gas generator 1 and the outlet 6 of the confinement space 5 supplying the circuit. 7 recirculation, so as to be fed by at least a portion of the flue gas flowing between the outlet 1 A fumes evacuation of the smoke generator 1 and the outlet 6 of the confinement space supplying the recirculation circuit 7.

In a manner that is characteristic of the invention, the flue gas recirculation circuit 7, connected at the inlet to the confinement space and at the outlet to the combustion chamber 100 of the said flue gas generator 1, emerges at the outlet in the hot zone of the 1 fumes generator, the outlet 3 of the flue gas recirculation circuit 7 in the hot zone of the fumes generator 1 being distinct from the inputs 1 01 of air and 1 02 of fuel supply of the combustion chamber 100. The combustion chamber air and fuel supply intakes that are common or different therefore open into the combustion chamber at a place distinct from the outlet 3 of the circuit 7 of the combustion chamber. recirculation of fumes in said chamber. In the case of a burner boiler, it is noted, as shown in Figure 3, that the flue gas recirculation circuit opens into the smoke generator at the level of an area surrounding the burner flame. This outlet is preferably located closest to the so-called blue zone of the burner flame, that is to say, the hottest zone of the burner flame. This zone corresponds to the zone of the flame which is close to the nozzle 1 2 or flame holder 13 which is equipped with the burner. This ensures a better combustion of toxic or polluting elements contained in the fumes reinjected at this level.

In the example shown in FIGS. 1 and 2, where the boiler is equipped with a burner 2, the hot zone of the flue gas generator 1 corresponding to the location 105 reserved for the flame of the burner 2 is delimited by means of FIG. a duct 14 of the nozzle type having a tubular peripheral wall 140 surrounding the flame location of the burner 2, this wall 140 being provided with a through opening connected to the flue recirculation circuit and forming the outlet 3 of said circuit 7 of recirculation of fumes in the hot zone of the smoke generator 1. The nozzle is therefore coaxial with the burner flame in the lit state of the burner and is able to surround by delimiting the volume capable of being occupied by said flame.

In the case of a solid fuel boiler, the boiler having, at its location 1 04 suitable for being occupied by the fuel, a perforated fuel support 15, such as a grid, the air inlet 101 in the combustion chamber 100 emerges below said fuel support 15 and the flue recirculation circuit 7 opens into the combustion chamber 100 above said fuel support 15.

The flue gas treatment unit 4 is in turn disposed on the flue gas circulation circuit between the smoke evacuation outlet 1A of the flue gas generator 1 and the outlet 6 of the confinement space 5 supplying the circuit 7 of flue gas. recirculation, so as to be powered by at least one part of the flue gas flowing between the flue gas discharge output 1 A of the flue gas generator 1 and the outlet 6 of the confinement space supplying the recirculation circuit 7. Preferably, the treatment unit 4 comprises at least:

a reactor at least partially filled with reagents, at least one of which is selected from the group of reagents formed by lime, activated charcoal and granular urea

a filter such as a bag filter.

By means of the assembly as described above, it is possible to circulate the flue gases from the smoke generator to the smoke confinement space 5 and then to the smoke confinement space 5 towards the flue gas generator 1.

The installation further comprises means 8 for analyzing the flue gases flowing inside the installation, said flue gas analysis means 8 being able to emit signals, in particular electrical signals, as a function of the result of the analysis.

Two embodiments of the invention may be envisaged.

In a first embodiment of the invention according to FIG. 2, the treatment unit 4 is arranged in line with the smoke generator 1 and is interposed between the smoke generator and the smoke confinement space 5.

In this first embodiment, when the installation further comprises means 8 for analyzing flue gas flowing inside the installation, said flue gas analysis means 8 being able to emit signals , in particular electric, depending on the result of the analysis, the smoke generator 1 is equipped with flow control means supplying air to the burner 2 of the flue gas generator 1, said adjusting means being configured to be controlled from the signals supplied by the flue gas analysis means 8. In this embodiment, the means for adjusting the air supply rate of the burner 2 may be formed by a controlled air damper of said burner 2. The smoke generator 1 may also be equipped with means for controlling the flow rate of the burner 2. supply of fumes from the combustion chamber. Thus, by way of example, the air inlet 101 of the combustion chamber 1 of the smoke generator 1 and / or the outlet of the flue gas recirculation circuit 7 in the hot zone of the flue gas generator 1 are equipped with shutoff means configured to be controlled from the signals provided by the flue gas analysis means 8.

The operating principle of such an installation is as follows. The burner 2, supplied with air and fuel, such as fuel or gas, ensures the mixing of the fuel and the oxidant and injected into the combustion chamber of the boiler where the combustion of the mixture leads to the formation of fumes. These fumes are evacuated with the aid of an orifice or outlet 103 for evacuating the fumes from the combustion chamber of the fumes generator 1. They pass through the flue gas treatment unit 4 formed of a reactor arranged in series with a filter. During this passage, at least part of the pollutants and toxic elements contained in the fumes are removed since retained by the filter or in chemical reaction with the elements of the reactor. The fumes then arrive in the confinement space 5 before being driven towards the smoke generator to be reintroduced by an inlet shown at 3 in the figures in the combustion chamber of the generator as close as possible to the burner flame in the chamber. volume surrounding the burner flame. To facilitate this recirculation, forced air circulation means, such as a fan, are provided on the flue circulation circuit of said installation. The gas analysis means make it possible to stop the operating the burner or reducing the air supply rate of the burner when the results of said analysis means indicate a saturation of the fumes for example due to an extremely high rate of carbon dioxide or carbon monoxide. These gas analysis means also make it possible to influence the amount of flue gases recirculating in the combustion chamber.

In a second embodiment in accordance with that shown in FIG. 1, the treatment unit 4 is disposed on a branch 9 which can be closed bypassing the portion of the fluid circulation circuit extending from the discharge outlet 103 of the smoke from the smoke generator 1 to the outlet 6 of the confinement space 5 supplying the recirculation circuit 7. The bypass branch 9 is connected at the entrance to the confinement space 5 and opens, after passing through the treatment unit 4, in the open air.

In this second embodiment, when the installation is of the type further comprising means 8 for analyzing flue gas flowing inside the installation, said flue gas analysis means 8 being suitable to emit signals, in particular electric, depending on the result of the analysis, the closure member 10 of branch branch 9 is a controllable member from the signals emitted by said means 8 for analyzing the gases of the fumes.

Thus, the operation of such an installation can be the following. Again, the burner 2 performs the air / fuel mixture before injecting this mixture into the combustion chamber of the boiler. The ignition of this mixture leads to the production of fumes that are removed from the combustion chamber of the boiler through an outlet 103 for exhausting fumes. These fumes then enter the confinement space 5 of said fumes. It should be noted that a non-return shutter member may be provided on the connection between the smoke discharge outlet 1A of the combustion chamber of the boiler and entry into the smoke confinement space 5 to avoid a discharge of fumes into the combustion chamber of the boiler. The gases can be analyzed in this flue gas containment space using gas analysis means 8. If the results of the analysis are correct, then all the smoke is removed from the smoke confinement zone 5 by the outlet 6 of the said confinement space 5 and takes the flue gas recirculation circuit 7 to be injected again into the combustion chamber of the boiler at the volume surrounding the burner flame as shown in Figure 3. If the gas analysis shows too much toxic elements or pollutants in the flue gas, then the 10 closing member, which closes the branches branch 9 and which is disposed at the level of the space 5 for confining gases is open to allow the evacuation of a portion of the fumes at the level of this branch 9 closable derivation. This branch 9 bypass passes through the processing unit before opening into the open air. The fumes are thus treated before being released into the atmosphere. As soon as the analysis results are again in accordance with those expected, the closing member 10 of the closable branch 9 is closed and the fumes then take the flue gas recirculation circuit. In a third embodiment according to FIG. 4, the solid fuel, such as charcoal, is introduced into the combustion chamber and is supported by the perforated fuel support 1 5. Fresh air is introduced under the support of fuel. The fuel is ignited resulting in the formation of fumes. These fumes are evacuated with the aid of an orifice or outlet 103 for evacuating the fumes from the combustion chamber of the fumes generator 1. They pass through the flue gas treatment unit 4 formed of a reactor arranged in series with a filter. During this passage, at least a portion of the pollutants and toxic elements contained in the fumes are eliminated since retained by the filter or in chemical reaction with the elements of the reactor. The fumes then arrive in the confinement space 5 before being driven towards the smoke generator to be reintroduced by an inlet represented at 3 in FIGS. in the combustion chamber of the generator. The flue gas recirculation circuit 7 opens into the combustion chamber 100 above said fuel support 15. Independently of the embodiment chosen, preferably, the space 5 for confining fumes is delimited by means of a hollow structure whose interior volume is compartmentalized using baffles. In a particular embodiment, this space 5 of smoke containment can be delimited by means of an inflatable structure. This confinement space 5 can be semi-buried or completely buried.

In the case where the boiler is equipped with a burner 2, the burner 2 has a predetermined air ratio, by construction, the maximum air supply flow rate of said burner expressed in m ³ / h, and the volume the space 5 of confinement expressed in m ³ is equal to at least 10 times the maximum air supply flow rate of said burner 2 expressed in m ³ / h.

Claims

1. Installation for the production and treatment of fumes, of the type comprising at least:

a fume generator (1) comprising at least one boiler equipped, if necessary, with a burner (2), said boiler comprising a combustion chamber (100) equipped with at least one air inlet (101), a fuel supply inlet (102), a flue gas outlet (103), and a fuel occupying location (104) and / or a location (105); ) reserved for the flame of the burner (2) when the latter is present, this or these location (s) (104, 1 05) forming the or a combustion chamber hearth (100) being called (s) the hot zone the generator (1) of fumes,

at least one space (5) for confining the fumes produced by said smoke generator (1), this space (5) for confining the fumes, connectable as input to the outlet (103) for evacuation of the fumes from the generator (1) ) of fumes, being connected at the output to said smoke generator (1) by a recirculation circuit (7), for a recirculation of the fumes inside said fumes generator (1),

a flue gas treatment unit (4) disposed between the flue gas outlet (103) of the flue gas generator (1) and the outlet (6) of the flue gas space (5). ) for supplying the recirculation circuit (7), so as to be supplied by at least a portion of the fumes flowing between the flue gas discharge outlet (1A) of the flue gas generator (1) and the outlet (6) of the confinement space supplying the recirculation circuit (7),

characterized in that the flue gas recirculation circuit (7), connected at the outlet to the combustion chamber (1 00) of said smoke generator (1), opens into the hot zone of the smoke generator (1), this outlet ( 3) of the flue gas recirculation circuit (7) in the hot zone of the smoke generator (1) being distinct from the air inlets (101) and fuel supply (102) of the combustion chamber (100).

2. Installation according to claim 1,

characterized in that the outlet (3) of the flue gas recirculation circuit (7) in the hot zone of the flue gas generator (1) is disposed downstream of the air inlet (101) of the chamber (100) of combustion taken in the flue gas flow direction within said combustion chamber (100).

3. Installation according to one of the preceding claims,

characterized in that the boiler being equipped with a burner (2), the hot zone of the smoke generator (1) corresponding to the location (105) reserved for the flame of the burner (2) is delimited with the aid of a duct (14) of the nozzle type having a tubular peripheral wall (140) surrounding the flame location of the burner (2), this wall (140) being provided with a through opening connected to the flue gas recirculation circuit and forming the outlet (3) of said flue gas recirculation circuit (7) in the hot zone of the flue gas generator (1).

4. Installation according to one of the preceding claims,

characterized in that the solid fuel boiler has, at its location (104) adapted to be occupied by the fuel, a perforated fuel support (15), such as a grid, the inlet (101) of which air in the combustion chamber (100) opens out beneath said fuel support (15) and the flue gas recirculation circuit (7) opens into the combustion chamber (100) above said fuel support (15).

5. Installation according to one of the preceding claims,

characterized in that the boiler being equipped with a burner (2), the burner (2) has a predetermined air register, by construction, the maximum air supply flow rate of said burner expressed in m ³ / h, and in that the volume of the confinement space (5) expressed in m ³ is equal to at least 10 times the maximum air supply flow rate of said burner (2) expressed in m ³ / h.

6. Installation according to one of claims 1 to 5,

characterized in that the treatment unit (4) comprises at least:

- a filter.

7. Installation according to one of claims 1 to 6,

characterized in that the treatment unit (4) is arranged in line with the smoke generator (1) and is interposed between the smoke generator and the smoke confinement space (5).

8. Installation according to one of claims 1 to 6,

characterized in that the treatment unit (4) is disposed on a branch (9) which can be closed bypassing the portion of the fluid circulation circuit extending from the generator flue outlet (103) (1). ) of fumes to the outlet (6) of the confinement space (5) supplying the recirculation circuit (7).

9. Installation according to claim 8,

characterized in that the derivation branch (9) is connected at the inlet to the confinement space (4) and opens, after passing through the treatment unit (4), into the open air.

10. Installation according to one of the preceding claims,

characterized in that it further comprises means (8) for analyzing the gases flue gases circulating inside the installation, said means (8) for analyzing the gases of fu mées being able to emit sig particularly electric, depending on the result of the analysis.

1 1. Installation according to claim 10,

characterized in that the air inlet (101) of the combustion chamber (100) of the smoke generator (1) and / or the outlet of the flue gas recirculation circuit (7) in the hot zone of the flue gas generator (1) are equipped with shutter means configured to be controlled from the signals supplied by the means (8) for analyzing the flue gas.

12. Installation according to claim 10 taken in combination with claim 8,

characterized in that the member (10) for closing the branch (9) bypass is a controllable member from the signals emitted by said means (8) for analyzing flue gases.

13. Installation according to one of claims 1 to 12,

characterized in that the space (5) for confining the fumes is delimited by means of a hollow structure whose internal volume is compartmentalized by means of baffles.

14. A method for producing and treating flue gases using a flue gas production and treatment plant according to one of claims 1 to 13, said method comprising:

at least one step for producing the fumes inside the combustion chamber (100) of the boiler of said installation,

a step of confining the fumes discharged from the boiler combustion chamber (100) through the smoke evacuation outlet (103) of said combustion chamber (100) into a confinement space (5) of said installation ,

a step of supplying the fumes from the smoke confinement space (5) into the combustion chamber (100) of the boiler via a flue gas recirculation circuit (7),

- A fumes treatment step with a treatment unit (4) is adapted to be fed by at least a portion of the flue gas flowing between the outlet (103) of the fumes of the generator (1). fumes and the outlet of the confinement space (5) supplying the recirculation circuit (7), characterized in that the smoke is brought into the combustion chamber (100) of the boiler of the smoke generator by means of the flue gas recirculation circuit (7) opening directly into the hot zone of the smoke generator (1). and in that the combustion chamber (100) of the boiler is supplied with air and fuel using at least one inlet (101) of air and one inlet (102) of fuel. distinct from the outlet (3) of the flue gas recirculation circuit (7) in said combustion chamber (100).