EP0970326A1

EP0970326A1 - Incinerator and method for incinerating liquid, pasty and solid waste

Info

Publication number: EP0970326A1
Application number: EP98917264A
Authority: EP
Inventors: Humbert Marin Olmotti
Original assignee: Individual
Current assignee: Individual
Priority date: 1997-03-28
Filing date: 1998-03-27
Publication date: 2000-01-12
Also published as: WO1998044297A1; AU7052998A; IL132024A0; FR2761458B1; FR2761458A1; CA2284878A1

Abstract

The invention concerns an incinerator for liquid, pasty and solid waste, characterised by its architecture with operating stages comprising, from the top downwards: a fourth level (N4) comprising means (5, 11) for introducing waste and means for maintaining, inside said fourth level (N4) constituting the incinerator top part, a temperature less than the flammability temperature of the waste to be incinerated; a third level (N3) arranged for ensuring said waste combustion at high temperature; a second level (N2) arranged for completing solid waste combustion; a first level (N1) comprising means (25, 26) for receiving and evacuating ashes.

Description

Incinerator and method for incinerating liquid, pasty and solid waste.

The present invention relates to an incinerator of liquid, pasty and solid waste, such as industrial waste, agricultural waste, hospital waste, medical care waste and household waste.

It also relates to a process for incinerating such waste, using this incinerator.

Current waste incinerators of the aforementioned type are most often produced in the form of large and complex industrial units comprising specialized ovens or boilers for waste disposal according to their nature: liquid, pasty or solid. Such waste incineration plants require large spaces and considerable investment for their construction and operation. Their design and volumes make them poorly integrated into the urban or rural environment.

In document FR-2.350.550 A, for example, an incineration plant is described, the configuration of which does not allow:

- incineration of liquid and pasty waste;

- total elimination of gases from the distillation or pyrolysis of solid waste introduced into the reaction tank of the installation;

- control of pyrolysis and incineration temperatures for solid waste.

In document WO 93 / 19324A, an installation is described, the construction of which does not allow:

- control of the incineration temperatures, in the upper and lower part of the combustion chamber;

- the maintenance, in the incineration zone, for the necessary time, of the high temperatures essential to obtain the total elimination of the gaseous products resulting from pyrolysis or from the combustion of waste. An object of the invention is to provide a versatile incinerator that complies with legislative and regulatory standards and allows the total elimination of waste of all kinds (liquids, pastes and solids), while being of simple construction, operation and maintenance. .

According to the invention, this objective is achieved thanks to a remarkable incinerator by an architecture with function stages comprising successively and from top to bottom:

a fourth level comprising means for the controllable introduction of solid, liquid or pasty waste, and means making it possible to maintain, inside this fourth level constituting the upper part of the incinerator, a temperature below the temperature flammability of the waste to be incinerated, for example a temperature between 150 ° C and 200 ° C;

a third level arranged and equipped with means capable of maintaining a temperature of at least 1200 ° C. inside this third level and of slowing down the evacuation of the fumes from this high temperature zone;

- A second level arranged to complete the combustion of solid products (in which, for example, a temperature of the order of 800 ° to 900 ° C is maintained);

- and a first level arranged for the reception and the evacuation of the ashes.

This multi-stage incinerator allows the destruction of liquid, pasty and solid waste with very low calorific value and which can contain up to 70% humidity.

It has a faster destructive capacity than in a conventional incinerator and still has, in particular, the following advantages:

- simple and quick start-up;

- reduced energy consumption during the ignition time of the waste; - great autonomy in non-stop walking;

- high operational safety;

- total combustion of the waste, the ultimate residues being reduced to the state of dust;

- simplified maintenance;

- compliance with anti-pollution standards in force, with gases released into the atmosphere, harmless, odorless and invisible.

- a better possibility of integration into the urban or rural landscape.

According to the process of the invention, regulated quantities of waste are introduced into the incinerator, on the one hand, according to their state (solid, liquid or pasty), and, on the other hand, according to their calorific value, in order to independently maintain a temperature of at least 1200 ° C. in the high temperature zone of the incinerator, for example over a height of the order of 1200 mm, preferably with an addition of air regulated according to this calorific value.

According to another characteristic arrangement of the process of the invention, the introduction, into the upper level of the incinerator, of products presenting risks of explosion due to their more or less significant content of flammable material, is carried out in presence of a water supply in the liquid state, or by vaporization, these products being able to be introduced by vaporization in the form of a mixture with water.

The aims, characteristics and advantages above, and others still, will emerge more clearly from the description which follows and from the appended drawings in which:

Figure 1 is a front view, schematic in vertical section, of the functional stage incinerator according to the invention. Figure 2 is a schematic view, in vertical section and on a larger scale, of the upper stage of the incinerator.

Figure 3 is a top view and schematic of the top of the incinerator.

Figure 4 is a detail view showing one of the cooling devices of the upper part of the internal side wall of the device.

Figure 5 is a top view of the liquid or pasty waste distribution device installed in the upper part of the device.

Figure 6 is an axial sectional view and schematic of the third level of the incinerator.

Figure 7 is a detail view, on a larger scale and in section, of a retarder device installed in the lower part of the third level of the device.

Figure 8 is a sectional view along line 8-8 of Figure 1.

Figure 9 is a sectional view along line 9-9 of Figure 1.

Figure 10 is a sectional view along line 10-10 of Figure 1.

Figure 11 is a cross-sectional view illustrating the profile of the charging grid arranged in the lower part of the third stage, above the retarder and the ignition burner.

FIG. 12 is a detail view, on a larger scale, of FIG. 11.

Figure 13 is a schematic view in median section of the lower part of the device comprising the second and first levels thereof.

Figure 14 is a plan view of Figure 13. Reference is made to said drawings to describe an interesting, although in no way limiting, embodiment of the waste incinerator according to the invention.

This incinerator comprises an outer vertical wall or envelope 1 and an inner vertical wall or body 2, between which an annular space is reserved; these walls, as well as the various essential component parts of the apparatus described below, being advantageously made of refractory stainless steel, in particular of special chromium-nickel-molybdenum steel, the walls of the combustion chamber can advantageously be made of austenitic refractory steel. The walls 1 and 2 may have a circular cross section, as illustrated, but they could also have a square, rectangular or other horizontal section.

According to a characteristic arrangement of the invention, the incinerator is arranged so as to have function stages comprising successively, from top to bottom:

a fourth level N4 comprising means for the controllable introduction of solid, liquid or pasty waste, and means making it possible to maintain, inside said fourth level constituting the upper part of the incinerator, a temperature below the temperature flammability of the waste to be incinerated, for example a temperature between 150 ° C and 200 ° C;

a third level N3 arranged and equipped with means capable of maintaining a combustion temperature of at least 1200 ° C. inside this third level, and of slowing down the evacuation of the combustion gases and the fumes from this zone high temperature;

a second level N2 arranged to complete the combustion of the solid products;

- and a first level N1 arranged for the reception and evacuation of the ashes.

The arrangement of these four stages is described below in succession. The upper end of the fourth level N4, that is to say the upper end of the apparatus, is closed. The upper end of the annular smoke collector C1 constituted by the space formed between the side walls 1 and 2 is closed by a horizontal wall 3 in the form of a circular crown, while the upper end of the upper chamber C2 delimited by the inner wall 2 is closed by a dome-shaped wall 4.

In the upper wall 4 is provided at least one inlet and, preferably, a plurality of inlets 5 (five inlets according to the example illustrated), for the introduction of liquid or pasty waste into the incinerator. These inlets which can have different and adjustable flow rates, due to their allocation (introduction of liquid or pasty products) are mainly constituted by pipes passing through the wall 4 and provided with solenoid valves or other shutters for adjusting the inlet of the products.

The liquid or pasty waste inlet pipes 5 pass through the upper wall or cap 4 and open into the chamber C2, above a distribution device 6 making it possible to disperse said liquid or pasty waste flowing from said pipes to the inside said chamber. The inlet pipes 5 are for example assembled in the central part of the upper cap 4 and they open out above a dispersing device 6 constituted by a convex circular sheet (in the form of a cone or spherical cap). To promote this dispersion, the disperser is provided with corrugations 6a at its periphery (Figure 5).

The upper wall or cap 4 of the device is also provided with means for injecting water into the upper part of the incinerator. According to the example illustrated, the device is in particular provided with four cooling water injectors 7 spaced at 90 ° and arranged near the periphery of said cap.

These cooling water injectors are, for example, constituted by pipes passing through the upper cap 4 and equipped with solenoid valves or other shutters allowing their flow to be adjusted. The internal end of these pipes fitted with an appropriate nozzle (spray nozzle or other), is oriented towards the internal surface 2a of the internal side wall 2, so that the jet of cooling water is projected against this surface (FIG. 4).

The cooling water injectors 7 have a double function:

- on the one hand, prevent liquid or pasty waste from igniting before it reaches the incinerator's hearth; and,

- on the other hand, prevent an excessive rise in temperature in the upper stage of the device, which would cause damage to the equipment fitted to the upper cap 4 of the incinerator.

The cooling or control water introduced into the upper part of the incinerator is not necessarily pure water; it may be, in fact, water pumped into the settling tank of a smoke washing device, which makes it possible to eliminate the sludge produced by this device, by incinerating it.

The method and the cooling means 7 make it possible to maintain, inside the level N4, a temperature below the combustion temperature of the waste to be incinerated, which is for example between 150 ° and 200 ° C.

In applications where the implementation of the cooling means described above would not make it possible to maintain a temperature below 200 ° C. in the upper part of the device, provision is made for additional cooling of said upper part (upper cap 4, upper wall 3 and side wall 1), by means of a water jacket 29, with inlet 29a and outlet 29b allowing circulation of the cooling water.

The water injection means equipping the upper cap 4 also comprise at least one water injector 8 which, according to the example illustrated, is constituted by an axial pipe passing through said upper cap and also the dispersing device 6. The water injector (s) 8 in particular have the aim of reducing the degree of flammability of certain waste presenting risks of explosion, because of their high content of flammable material; in this case, these products are vaporized in the central upper part of the incinerator in the presence of water or water vapor, for example in the form of a mixture with water.

The central water injector 8 has in particular the function of allowing the rapid extinction of the appliance hearth, when it proves necessary to stop the operation of the incinerator.

The upper cap 4 can be provided, externally, with gussets 9 allowing the attachment of a lifting device sling.

Laterally, the upper stage N4 of the device is provided with:

- On the one hand, a smoke outlet 10 shaped to be able to be connected, in any known manner, to a smoke duct, by means of a smoke washing system; and,

- on the other hand, an inlet 11 for the introduction of solid waste.

The smoke outlet 10 communicates with the upper part of the smoke collector C1, while the solid waste inlet 11 opens into the chamber C2, this inlet comprising, for example, a cylinder passing through the annular smoke collector C1 and communicating with room C2.

Solid waste is, for example, brought to inlet 11, by means of a worm conveyor, itself supplied by a crusher, after sorting said waste.

In the smoke collector C1 and at the level of the lower part of the chamber C2, a horizontal partition 12 is installed in the form of a crown and provided with holes 13 arranged around the inner wall 2. These holes 13 are slightly spaced and their diameter is barely less than the distance between the outer 1 and inner 2 walls. The perforated partition 12-13 serves to disperse the heat around the internal chamber C2, the mixture of hot air and burnt gases being unable to rush directly towards the flue, this mixture being distributed uniformly through the holes 13 in all points of the upper part of the smoke collector C1.

This arrangement also makes it possible to avoid the flashback.

The upper stage of the apparatus is equipped, externally or internally, with various devices known per se and necessary for the perfect functioning of said apparatus, such as electro-valves for opening / closing and regulating flow, temperature sensors, regulators, pollutant control sensors, safety valves, etc. For example, one or more temperature sensors installed in the upper part of the incinerator can be connected to a programmable automaton allowing, depending on the temperature indications transmitted by this or these sensors, to control means for automatic introduction into the upper part of the incinerator, of waste with low calorific value and of waste with high calorific value, in the desirable proportions to obtain a mixture capable of being incinerated by generating a temperature of at least 1200 ° C. in the lower part of the combustion chamber C3 described below.

In the upper part N4 of the incinerator can be provided, laterally, an opening (not shown) provided with an airlock for the introduction of contaminated waste, so that the latter cannot be heated with release of toxic vapors before closing complete of said opening.

The third stage N3 includes a central combustion chamber

C3 delimited by the internal side wall 2 and communicating freely with the chamber C2. The central combustion chamber C3 is surrounded by the lower part of the smoke collector C1 which communicates with the upper part of the latter, through the holes 13 which the horizontal wall 12 presents. The lower part of the high temperature combustion chamber C3 communicates with the smoke collector C1, through a retarder assembly 14 installed at said lower part, which aims to slow the escape of the air / combustion gas mixture in it imposing a baffle course in the lower part of room C3. This retarder assembly can advantageously be constituted by a plurality of perforated cylindrical belts 14a, 14b, 14c, 14d, arranged concentrically around the axis of the chamber C3 and spaced from one another. The perforations 14a ', 14b', 14c ', 14d' of these belts have diameters which decrease from the center outwards, as shown in Figure 7.

The smaller diameter perforations 14d ′ of the outer perforated belt 14d open into the lower part of the smoke collector C1.

At least one burner 15 is installed at the height of the retarder assembly. This burner passes through the set of perforated belts 14a, 14b, 14c, 14d, so that its combustion head is placed in the space delimited by the internal perforated belt 14a of said set of belts (FIG. 9).

The burner 15 can be gaseous fuel or liquid fuel. It is used for starting ignition of the incinerator.

It allows combustion to be started at the various desired temperatures and stops at the programmed temperature at the end of the start-up period.

Above the retarder assembly is mounted an inclined grid 16 consisting of bars, one or more of which can be cooled by circulation of water or other cooling fluid.

Advantageously, this grid consists of tubular bars 16a, 16A and bars 16b having a very open V profile, preferably arranged alternately. The tubular bars 16A, 16a preferably have a square section and they are oriented so as to have two upper faces 16a 'inversely inclined. The inclined faces 16a ′ of the central bar 16A have an overhanging lateral part 16a "ending above one of the wings of the neighboring bar 16b (FIG. 12). In this way, there is no vertical passage between the central bar 16A and the two V-shaped bars placed on either side of the latter. The ignition burner 15 is arranged below the central bar assembly 16b-16A-16b and is therefore protected by this set.

Vertical passages 30 are provided between the other bars 16a, 16b of the grid 16.

The tubular bars 16A, 16a are connected, respectively, to an inlet pipe and to an outlet pipe (not shown) allowing the circulation of a cooling fluid (water or other) inside said bars.

It is observed that during the operation of the incinerator, a layer of ash is deposited on the inclined surfaces 16b 'of the V-shaped bars 16b, this layer of ash constituting a protection of said bars against the effects of the high temperature maintained in the chamber C3 .

The upper central part of the grate 16 is disposed above the burner 15 as indicated above, while its lower part leads to an outlet hatch 17 fitted to the side wall of the incinerator. This grid has many functions:

- It retains liquid or pasty waste which has not been burned when it enters the high temperature hearth, so as to allow their combustion;

- It retains solid waste for the time necessary for their calcination, while allowing the fall of calcined waste in the underlying stage N2;

- It allows the routing of refractory waste towards the outlet hatch 17;

- it protects the burner 15. In the lower part of the combustion chamber, opens at least one compressed air injector 18. Preferably, the incinerator is equipped with a plurality of injectors and, for example, four injectors 18 spaced 90 ° , opening above the retarder assembly 14.

These injectors are connected to a compressor or other blower system and allow the introduction of compressed air into the fireplace. Their number and flow rate depend on the capacity of the incinerator.

This injection of compressed air is used to regulate the temperature of the hearth, that is to say to maintain in the lower part of the chamber C3, a temperature of at least 1200 ° C. necessary to destroy certain molecules, depending on the nature. waste to be disposed of.

To allow total oxidation and complete destruction of waste, high heating temperatures must be reached and modulated, depending on the nature and the calorific value of said waste, by injecting variable amounts of air, particularly into the hearth high temperature C3, using the air inlet solenoid valves of different diameters.

The air / combustion waste / burnt gas mixture is pushed down under the pressure of the compressed air injected into the combustion chamber C3, and escapes into the annular smoke collector C1 under the suction effect. created by the chimney, passing through the perforations of the set of perforated belts 14a, 14b, 14c, 14d, which make it possible to slow down its circulation by lengthening its path. Thanks to the implementation of this incineration process, certain apyrious molecules are stationed in the lower part of the upper high temperature hearth, for the time necessary (four seconds or more, at 1200 ° C) until their complete destruction.

The incinerator can be equipped, at the level of the compressed air injectors 18, with injectors (not shown) of gaseous waste which can thus ignite instantly, as soon as they enter the upper hearth C3. The side wall 2 of the combustion chamber C3 is cooled by means of a water jacket disposed around the lower part of said wall.

For this purpose, an annular chamber C4 with at least one water inlet 19 and at least one water outlet 20, surrounds the lower part of the wall 2, this chamber being delimited, externally, by a wall 21 arranged, concentrically , around the wall 2 and at a distance therefrom, the annular space formed between these walls being closed at its upper and lower ends.

Laterally and at a level located above the grid 16, the incinerator is equipped with a door 22 for manual loading. This large door is intended for the introduction of bulky solid waste whose reduction into fragments of reduced size, by means of a grinder, is not possible or very difficult. It is pivotally mounted around a lower horizontal axis a-a ', by means of hinges (not shown).

The second stage of the incinerator consists of a set of superimposed grids 23 comprising at least two superimposed grids 23a, 23b.

This set of superimposed grids 23 is advantageously of the type described in document WO 93/19324, that is to say an assembly, the grids of which consist of flat bars 23a ′, 23b ′ inclined around their longitudinal axis, the flat bars 23a 'of one of the grids having an inverse inclination to that of the flat bars 23b' of the other.

The purpose of this set of grids is to retain partially calcined solid waste until it is completely incinerated.

This arrangement makes it possible to maintain a temperature of the order of 800 ° C to 900 ° C in the lower hearth constituted by the second stage of the incinerator.

The first stage N1 is arranged for the reception and the evacuation of the ashes. This stage comprises a movable ashtray 25 in the form of a funnel, arranged below the set of grates 23 and at the bottom of which is installed a device for extracting the ashes (ultimate residues), for example constituted by a screw without end of extraction 26 associated with a suction system making it possible to convey the ashes to a storage silo.

The ashtray 25 is, for example, equipped with rollers 28 on two of its opposite sides, these rollers resting on parallel raceways 27 rigidly secured to the lower part of the carcass of the device.

Cold air inlets 24 are provided in the side wall of the appliance, around the ash tank, which makes it possible to cool the ashes and to oppose the descent of the air introduced to the upper part (3rd floor) of the appliance.

A smoke washing device (not shown) can advantageously be installed between the smoke outlet 11 and the smoke duct. The washing effluents are collected in a settling tank and, as indicated above, these effluents can be pumped and introduced into the upper part of the incinerator to participate in the cooling of the upper stage of the latter, in addition, this process eliminates sludge from the smoke washing device.

The chimney (not shown) into which the smoke washing device opens, is equipped with a blower (turbine) allowing the ejection of the fumes at a speed of the order of 12 m / s, while creating a vacuum at the smoke outlet 11, necessary for the proper functioning of the incinerator.

The incinerator according to the invention allows the elimination of waste of any kind and any calorific value such as, in particular:

- liquid waste with low calorific value, for example: slurry, liquid manure, etc. ;

- high calorific liquid waste, for example: petroleum residues, etc. ; - pasty waste with low calorific value, for example: sludge from treatment plants, etc. ;

- pasty waste with high calorific value, for example: petroleum sludge, oils, etc. ;

- solid waste with low calorific value, for example: household waste, etc. ;

- solid waste with high calorific value, for example: paper, cardboard, various chemical compounds, resins, etc.

According to the process of the invention, regulated quantities of waste are introduced into the incinerator described above, on the one hand according to their state (liquid, pasty or solid) and, on the other hand, according to their calorific value, to keep, during use of the incinerator, a temperature of at least 1200 ^C C in the high temperature area N3 of the latter, for example to a height of about 1200 mm , preferably with a regulated air supply, as a function of this calorific value, in said high temperature zone.

According to this process, the signals supplied by the temperature sensors (not shown), for example of the S thermocouple type with double protective casing, installed in the combustion chamber, are processed by a programmable controller, which controls: - the means of transport of liquid and / or pasty, and / or liquid waste (positive displacement pumps for liquid or pasty waste; Archimedes screw conveyor for solid waste) in the desired quantities and proportions to the incinerator, - the injection of water at the top of the latter, and, - injection of pressurized air into the combustion chamber C3.

According to the process of the invention, a controlled mixture of liquid and / or muddy and / or solid waste with low calorific value and of liquid and / or muddy and / or solid waste with high calorific value, is introduced into the incinerator, the percentage of high calorific waste in this mixture being lowered, and the percentage of low calorific waste being proportionally increased, when the incineration temperature becomes higher than 1200 ° C, in the high temperature zone N3, while, conversely, the percentage of high calorific waste in the mixture is increased and the percentage of waste with low calorific value is lowered, when the incineration temperature in this area becomes lower than a predetermined low threshold, for example 1150 ° C.

According to another characteristic arrangement of the process of the invention, the introduction, into the upper level of the incinerator, of products presenting risks of explosion due to their high content of flammable material, is carried out in the presence of a supply of water injected in the liquid state or by vaporization, these highly flammable products being able to be introduced by vaporization in the form of a mixture with water.

Claims

1. - Liquid, pasty and solid waste incinerator, characterized by its multi-stage architecture comprising, from top to bottom:

- A fourth level (N4) comprising means (5, 11) for the controllable introduction of solid, liquid or pasty waste, and means making it possible to maintain, inside said fourth level (N4) constituting the upper part of the incinerator, a temperature below the flammability temperature of the waste to be incinerated, for example a temperature between 150 ° C and 200 ° C;

- A third level (N3) arranged and equipped with means capable of maintaining a combustion temperature of at least 1200 ° C inside this third level and of slowing the evacuation of the fumes outside this high temperature zone;

- a second level (N2) arranged to complete the combustion of solid products; and,

- a first level (N1) comprising means (25, 26) for receiving and removing the ashes.

2. - Incinerator according to claim 1, characterized in that the means making it possible to maintain, inside the upper level (N4) of said incinerator, a temperature below the flammability temperature of the waste to be incinerated, consist of a or several devices (7) for spraying cooling water against the internal wall (2) of said upper level (N4).

3. - Incinerator according to one of claims 1 or 2, characterized in that the inlets (5) of liquid or pasty waste are disposed on the cover cap (4) of said incinerator and open above a device for distribution (6) of said liquid or pasty waste.

4. - Incinerator according to claim 3, characterized in that the inlets (5) of liquid or pasty waste are collected on the central portion of the cover cap (4) and in that the distribution device (6) consists by a convex circular disperser, preferably having corrugations (6a) at its periphery.

5. - Incinerator according to any one of claims 1 to 3, characterized in that the third level (N3) comprises: - a high temperature combustion chamber (C3) disposed below the waste introduction chamber (C2) and communicating freely with the latter, this chamber (C3) being delimited by a side wall (2); - a charging grid (16) disposed at the lower part of said chamber (C3); - And one or more compressed air injectors (18) opening into the lower part of said chamber.

6. - Incinerator according to any one of claims 1, 2, 3 and 5, characterized in that it comprises an annular smoke collector (C1) disposed around the waste introduction chamber (C2) and around the high temperature combustion chamber (C3).

7. - Incinerator according to claim 6, characterized in that the high temperature combustion chamber (C3) communicates with the smoke collector (C1) through a retarder device (14) installed at the bottom of said chamber.

8. - Incinerator according to claim 7, characterized in that the retarder device (14) consists of a plurality of cylindrical perforated belts (14a, 14b, 14c, 14d) arranged concentrically and spaced from each other.

9. - Incinerator according to claim 8, characterized in that the cylindrical perforated belts (14a, 14b, 14c, 14d) have perforations (14a ', 14b', 14c ', 14d') whose diameters are decreasing from the center outward.

10. - Incinerator according to any one of claims 1 to 9, characterized in that at least one burner (15) is installed in the lower part of the high temperature incineration chamber for the start-up ignition of said incinerator , this burner (15) preferably opening into the space delimited by the internal grid (14a) of the set of grids (14).

11. - Incinerator according to one of claims 5 or 10, characterized in that the charging grid (16) has an inclined position in the direction of a hatch (17) for evacuating refractory waste.

12. - Incinerator according to one of claims 5 or 11, characterized in that the charging grid comprises tubular bars (16a) cooled by internal circulation of water and bars (16b) provided with a V profile.

13. - Incinerator according to any one of claims 5, 11 or 12, characterized in that the bars (16a, 16b) of the charging grid (16) have at least one inclined plane surface (16a ', 16b') waste reception.

14. - Incinerator according to any one of claims 1 to 13, characterized in that its second level (N2) consists of a set of superimposed grids (23).

15. - Incinerator according to claim 14, characterized in that the grids (23a, 23b) of the set of superimposed grids (23) are constituted by flat bars (23a ', 23b') inclined around their longitudinal axis, the flat bars (23a ') of one of the grids having an inverse inclination to that of the flat bars (23b') of the other grid.

16. - Incinerator according to any one of claims 1 to 15, characterized in that a smoke washing device is installed between the smoke outlet (11) of said incinerator and the smoke duct.

17. - A method of incinerating liquid, pasty and solid waste, using an incinerator according to any one of claims 1 to 16, characterized in that one introduces, into this incinerator, regulated quantities of waste, on the one hand, according to their state (solid, liquid or pasty) and, on the other hand, according to their calorific value, in order to maintain, during the period of use of the incinerator, a temperature of at least 1200 ° C in the high temperature zone (N3) of the latter, for example over a height of the order of 1200 mm, with, preferably, a supply of regulated air, as a function of this calorific value, in said zone .

18. - Method according to claim 17, characterized in that the signals supplied by temperature sensors installed in the combustion chamber (C3) of the incinerator, are processed by a programmable controller, which controls:

- the means of transporting liquid, and / or pasty, and / or solid waste, in the desired quantities and proportions, up to said incinerator;

- water injection in the upper part of the latter; and,

- injection of pressurized air into the combustion chamber (C3).

19. - Method according to one of claims 17 or 18, characterized in that a controlled mixture of liquid and / or muddy and / or solid waste with low calorific value and of liquid and / or muddy waste and / or high calorific value is introduced into the incinerator, the percentage of high calorific waste in this mixture being lowered and the percentage of low calorific waste being proportionally increased, when the incineration temperature becomes higher than 1200 ° C in the high temperature zone N3, while, conversely, the percentage of high calorific waste in the mixture is increased and the percentage of low calorific waste is lowered, when the incineration temperature in this zone becomes lower at a predetermined low threshold, for example 1150 ° C.

20. - Method according to any one of claims 17 to 19, characterized in that the incinerator of products presenting risks of explosion due to their high content of flammable material, is carried out in the presence of a contribution of water injected in the liquid state or by vaporization, these highly flammable products being able to be introduced by vaporization in the form of a mixture with water.

21. - Method according to any one of claims 17 to 20, characterized in that cooling water is injected into the upper part (N4) of the incinerator, in order to maintain, in this part, a lower temperature at 200 ° C.

22. - Method according to any one of claims 18 to 21, characterized in that the water used for regulating the temperature is taken from the smoke settling tank.