EP3885651A1 - Rotary de-ashing grate system for furnace of a combustion or gasification installation - Google Patents

Rotary de-ashing grate system for furnace of a combustion or gasification installation Download PDF

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Publication number
EP3885651A1
EP3885651A1 EP21163539.6A EP21163539A EP3885651A1 EP 3885651 A1 EP3885651 A1 EP 3885651A1 EP 21163539 A EP21163539 A EP 21163539A EP 3885651 A1 EP3885651 A1 EP 3885651A1
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EP
European Patent Office
Prior art keywords
plates
plate
lower plate
fuel
air
Prior art date
Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
Granted
Application number
EP21163539.6A
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German (de)
French (fr)
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EP3885651B1 (en
EP3885651C0 (en
Inventor
Jean RIONDEL
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Mini Green Power
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Mini Green Power
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Publication of EP3885651B1 publication Critical patent/EP3885651B1/en
Publication of EP3885651C0 publication Critical patent/EP3885651C0/en
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Classifications

    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F23—COMBUSTION APPARATUS; COMBUSTION PROCESSES
    • F23H—GRATES; CLEANING OR RAKING GRATES
    • F23H7/00—Inclined or stepped grates
    • F23H7/06—Inclined or stepped grates with movable bars disposed parallel to direction of fuel feeding
    • F23H7/08—Inclined or stepped grates with movable bars disposed parallel to direction of fuel feeding reciprocating along their axes
    • C—CHEMISTRY; METALLURGY
    • C10—PETROLEUM, GAS OR COKE INDUSTRIES; TECHNICAL GASES CONTAINING CARBON MONOXIDE; FUELS; LUBRICANTS; PEAT
    • C10J—PRODUCTION OF PRODUCER GAS, WATER-GAS, SYNTHESIS GAS FROM SOLID CARBONACEOUS MATERIAL, OR MIXTURES CONTAINING THESE GASES; CARBURETTING AIR OR OTHER GASES
    • C10J3/00—Production of combustible gases containing carbon monoxide from solid carbonaceous fuels
    • C10J3/02—Fixed-bed gasification of lump fuel
    • C10J3/20—Apparatus; Plants
    • C10J3/34—Grates; Mechanical ash-removing devices
    • C10J3/40—Movable grates
    • C10J3/42—Rotary grates
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F23—COMBUSTION APPARATUS; COMBUSTION PROCESSES
    • F23H—GRATES; CLEANING OR RAKING GRATES
    • F23H9/00—Revolving-grates; Rocking or shaking grates
    • F23H9/02—Revolving cylindrical grates
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F23—COMBUSTION APPARATUS; COMBUSTION PROCESSES
    • F23K—FEEDING FUEL TO COMBUSTION APPARATUS
    • F23K3/00—Feeding or distributing of lump or pulverulent fuel to combustion apparatus
    • F23K3/10—Under-feed arrangements
    • F23K3/14—Under-feed arrangements feeding by screw
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F23—COMBUSTION APPARATUS; COMBUSTION PROCESSES
    • F23H—GRATES; CLEANING OR RAKING GRATES
    • F23H2700/00—Grates characterised by special features or applications
    • F23H2700/005—Rotary grates with vertical axis

Definitions

  • the present invention relates to an ash grate system for the hearth of a combustion or gasification plant supplied with solid fuel, said grate system comprising a lower circular plate of diameter D1 and of surface S1 mounted to rotate 360 ° along an axis. vertical rotation A, and an installation comprising such an ash grid system.
  • Combustion or gasification plants include a hearth inside which a fixed bed of a solid fuel, for example biomass, is burned to provide heat. They also generate residues, such as ash, char or various unburnt materials, which must be continuously evacuated out of the hearth, to avoid downtime. To this end, the combustion or gasification installations according to the prior art are equipped with ash grid systems.
  • the grid systems are advantageously designed to respond to various problems in combustion or gasification installations, among which - the reception of the fuel injection system in the home; - the setting in motion of the fuel to advance the fuel towards the ash evacuation system, the drive system having to be adapted to the heat and the presence of any dust, and to be protected; - control of the feed rate of the fuel bed to avoid the formation of unburnt (too short residence time) or bottom ash (too long residence time).
  • Some ash grid systems have been developed to respond to some or all of the issues outlined above. Some systems include vibrating grids, others include rotating grids, still others include tilting grates, and finally others include stepped grates.
  • a problem which the invention proposes to solve is to provide an ash grid system for the hearth of a combustion or gasification installation supplied with solid fuel, which overcomes the aforementioned problems of state of technique.
  • This system also responds to the variability of the composition of the fuel, which requires varying the residence times of the ash on the grate depending on the nature of the ash evacuated. If the ashes coming out of the grates are agglomerated or partially melted: the residence time is too long. You have to increase the speed of some trays. If the ashes contain unburnt material, the residence time must be extended.
  • the first object of the solution of the invention to this problem posed is an ash removal grid system for the hearth of a combustion or gasification installation supplied with solid fuel, said grid system comprising a lower circular plate of diameter D1 and of surface S1 mounted to rotate 360 ° along a vertical axis of rotation A, and characterized in that it further comprises at least one upper plate, superimposed on said lower plate, and mounted to rotate 360 ° along the vertical axis of rotation A , said at least one upper plate having a surface S2 less than the surface S1 of the lower plate and a maximum dimension at most equal to the diameter D1 of this lower plate, said plates being movable, the center of gravity of said plates (being on the axis of rotation A, the upper plate (s) having a shape different from the circular shape and a greater dimension substantially equal to the smallest dimension of the plate on which they are superimposed, the lower and upper plates not rotating at the same speed.
  • each plate can be rotated according to a speed of rotation Vi, this speed rotation being variable over time as a function of the composition of the fuel; - the speeds of rotation of the upper plates are different and are variable individually; - the system comprises a plurality of upper plates superimposed on one another, all of the upper plates being superimposed on the lower plate, the surface S2 of the plate immediately above the lower plate is inscribed in that S1 of said lower plate, and the surface S3, and possibly the surface S4, of the upper plate (s) positioned above the plate immediately above the lower plate decrease as a function of their position in the superposition of the plates; - the upper plates are not in a circular shape; the upper plate (s) have an elliptical shape; - the trays are openwork; - the trays have slits and / or openings; a circular fuel inlet is arranged at the center of the stack of trays, the center of said circular inlet being positioned substantially on the axis A and in that a tube connected to this inlet allows the
  • Its second object is a combustion or gasification installation supplied with solid fuel comprising a grid system as defined above.
  • the fuel has a variable composition.
  • a gasification or combustion installation according to the invention is intended to burn or gasify a solid fuel, in particular derived from biomass, with a view to producing heat.
  • the fuel is therefore inherently heterogeneous. Its composition is variable. In particular, it is more or less dry.
  • Such an installation according to the invention comprises a hearth which is arranged around a vertical axis of symmetry. This focus is delimited by a side wall, for example cylindrical.
  • the fuel is admitted into the furnace through a fuel inlet in correspondence with a fuel supply channel.
  • This supply channel is preferably formed of a vertical cylindrical tube centered on a set of superimposed turntables forming a grid. As the solid fuel enters the fireplace, vertically, from bottom to top, through the supply channel, to the fuel inlet, a mound of solid fuel forms on the grate .
  • the grid system 1 comprises a lower plate P1 and one or more upper plates.
  • the number of upper plates is advantageously two or three.
  • system 1 comprises three upper plates P2, P3 and P4.
  • the upper plate (s) P2 to P4 are positioned on the lower plate P1, stacked on this plate P1. All the plates P1 to P4 are rotating plates, mounted to be able to rotate about a vertical axis A at an angle of 360 °.
  • the lower plate P1 is mounted on a fixed circular base 2.
  • the lower plate P1 is circular with a diameter D. It is the largest of the plates.
  • the surface of the upper plates S2, S3, S4 is less than S1. These surfaces S2, S3 and S4 are decreasing: S2>S3> S4.
  • the upper plates are not circular. Examples of the shapes of these top trays are shown at figures 2A, 2B and 2C .
  • the plates P2 to P4 are in an elliptical shape.
  • the figures 2B they are triangular.
  • the figure 2C they are in a star.
  • the upper plates P2 to P4 have at least one larger dimension and smaller dimensions.
  • the largest dimension of the upper plate P2 positioned immediately above the lower plate P1 is equal or approximately equal to the diameter D of the lower plate P1.
  • the surface S2 of the upper plate P2 is less than that S1 of the lower plate.
  • the figures 3A and 3B have a superposition of two upper plates, for example the plates P2 and P3, the plate P3 being superimposed on the plate P2.
  • the plates P2 and P3 are elliptical. They therefore each have a greater dimension, namely the major axis of the ellipse, and a smaller dimension: the minor axis of this ellipse.
  • the major axis of the ellipse formed by plate P3 is approximately equal to or equal to the minor axis of the ellipse formed by plate P2.
  • the plates P2 and P3 are triangular and the triangles they define are equilateral.
  • the largest dimension of the triangle forming P3, namely the side of this triangle, is approximately equal to the smallest dimension defined by the triangle forming P2.
  • the plate P3 fits into the plate P2 with a greater dimension, for P3 equal or approximately equal to the smallest dimension of P2.
  • the shape of the upper plate (s) can be diverse as long as it combines the following characteristics.
  • the center of gravity of the platters is on the axis of rotation. This makes it possible to avoid having mechanical forces distributed in a non-symmetrical manner on the supports of the plate. This improves the life of the system.
  • this makes it possible to alternately cover and uncover the surface of the lower plate during the rotation. This makes it possible to "scrape" the surface of a lower plate by an upper plate and thus to advance the fuel towards the periphery of the reactor.
  • the thickness of the plates P1, P2, P3, P4 increases in the stacking of said plates in the grid system.
  • the lower plate P1 has a thickness of 100 mm
  • that of the upper plate P2 which is immediately above it has a thickness of 80 mm
  • that of the plate P3 is 60 mm
  • that of the plate P4 is 60 mm. This allows to train an equivalent amount of fuel for each tray.
  • Trays P1 to P4 are made so that they can be dismantled by portion to facilitate maintenance and installation operations. It also allows to optimize the maintenance cost by replacing only the portion of a damaged plate and not the entire plate.
  • the plates P1 to P4 are perforated so that the primary air can pass through said plates.
  • the plates have, for example, holes or slits.
  • they are provided with substantially radial slots, namely starting from the periphery of the plates and going towards the center thereof.
  • Some F1 slots are not complete and do not extend to the perimeter of the chainrings.
  • Other F2 slots are complete and extend to the periphery of the trays. They allow the platters to expand without creating distortion.
  • the slots F1, F2 advantageously extend, on the side of the center of the plates, by openings O that are wider than the slots F1, F2.
  • the slots F1, F2 may not be strictly positioned radially on the plates. In other words, they may not pass through the center of these. They are then slightly inclined so that, for the same number of slots, the surface allowing the passage of air is greater. In addition, it improves the strength of the chainrings. Furthermore, the slot surfaces are calculated so as to optimize the air flow rates and thereby the combustion / gasification profile of the solid fuel, at each plate.
  • the section of the slots is calculated so as to create a determined pressure drop of the air passing through them, ensuring a homogeneous flow rate per slot, independent of the local quantity of fuel located above, and in particular avoiding uncontrolled air leaks if there is a lack of fuel above the slots.
  • a circular fuel inlet 3 is arranged in the center of the plates P1 to P4 of the grid system 1. All the plates P1 to P4 can rotate around the axis of rotation A, identical to the axis of revolution of the fuel inlet 3.
  • the rotational movement of a given platen creates a relative motion with respect to the platens above and below and the elliptical shape, or the like, of the upper platens P2 to P4, which makes it possible to sweep the surface of the trays on which they are superimposed and to advance the fuel towards the outside.
  • Plates P1 to P4 do not rotate at the same time and at the same speed so that there is relative movement between the platters. In other words, each of the plates P1 to P4 rotates at a different speed. Furthermore, each of the plates can turn at a variable speed to adjust the ash residence time which must be variable depending on the nature of the ash.
  • the rotational speeds of the plates are adjustable independently of each other. They are independently controlled. They vary over time independently. We can have different speeds for each plate.
  • the plates rotate at variable speed depending on the nature of the fuel used.
  • the fact that the plates can vary their speed makes it possible to vary the residence time in the gasifier, depending on the nature of the fuel. and ashes. Too long a residence time may involve melting the ash and therefore blocking or even destroying the grate. Too short a stay rate leads to the presence of unburnt substances at the bottom of the grid, which reduces the efficiency of the installation and increases the risk of blockage.
  • waste by nature of variable composition, only a grid with variable speed of rotation can operate.
  • the grid according to the invention is the only one which can adapt to a composition of waste that varies over time.
  • a large slit 4 is fitted around the perimeter of the grate to evacuate the ashes.
  • the ashes are thus continuously evacuated from the hearth through this slot 4.
  • the grid system according to the invention is also designed so as not to create any point of accumulation of undesirable ash.
  • the function of the trays is to spread the fuel and bring the ashes to the outside, namely towards the wide slit 4, in order to evacuate them.
  • the fact that all the trays are movable has two advantages over systems with fixed trays. First, a single moving platen sweeps the fuel from the movable platen plus the fuel on the lower platen. There is therefore less need to run the engines for the same service. We save energy. In addition, the system is less sensitive to possible blockages. If a tray gets stuck for some reason, the trays above and below can be used to continue operating the grid, and therefore the power generation unit, time to plan and carry out a maintenance operation at the most convenient time. The availability of the grid system and the flexibility to repair is higher.
  • the ash present in the hearth is evacuated through the wide slit or groove 4 positioned around the entire periphery of the grate system.
  • the ashes fall through this slot onto a conveyor system, not shown in the figures, which allows the ashes to be brought into a storage space.
  • This wide slot 4 is made so that the larger pieces that can be injected into the hearth can be removed therefrom.
  • the majority of the ashes are pushed by the rotating plates towards the outside of the grate and therefore towards this slot 4.
  • ash of small dimensions can also be brought under the plates.
  • these small-sized ashes are likely to block or disrupt the flow of primary air. To avoid this phenomenon, scraping devices are fitted under the trays. These devices are not shown in the figures.
  • One or more openings can also be made at a point around the perimeter of the tray (s) so that the ashes fall into the throat.
  • the section of the opening is calculated precisely so as not to have a preferential air leak, which could affect the main air flow passing through the slots.
  • An injection system is used to supply the combustion chamber with primary air from two independent air inlets in the the system. These entries are referenced 5 and 6 in figures 6A and 6B .
  • These inlets 5 and 6 are primary air inlets of two independent air circuits: the cooling air circuit C1 and the main circuit C2.
  • the cooling air circuit C1 allows atmospheric air to pass through the system for rotating the system and to cool it to protect it from degradation due to a rise in temperature.
  • the primary air admitted into the inlet 5 thus makes it possible to cool the mechanical movement transmission system in order to preserve its integrity. This air also makes it possible to avoid any intrusion of ash dust into the mechanical part of the system according to the invention.
  • Part of this primary air is injected through this inlet 5 and emerges at the level of each plate, via a set of dedicated lights, arranged in each coaxial tube.
  • the injected air then joins the circuit under the trays of the grate system, before entering the solid fuel bed.
  • the second main circuit C2 allows most of the primary air flow to be injected into the fireplace through the grille.
  • This circuit is independent of the cooling circuit and is not in contact with sensitive mechanical parts. This makes it possible to inject preheated air or directly recirculate fumes of up to 200 ° C and be loaded with dust.
  • the air admitted into the inlet 6 therefore feeds the fireplace through the grille. Its flow is controlled.
  • the circuit corresponding to this input is never in contact with elements sensitive to temperature or dust.
  • a third air circuit is composed of an air ring denoted CA in Fig. 1 injection valve located on the periphery of the lower grille (the lower plate). It is used to finalize the combustion of any unburnt material on the lower grate. Flue gas recirculation optimizes the combustion of very dry and volatile fuels and reduces the production of atmospheric pollutants such as NOx.
  • quick-opening hatches 7 are advantageously arranged on the primary air circuit under the grid system. They allow the pipes of the air intake circuits to be quickly evacuated in the event of an accumulation of ash.
  • the rotational movements of the plates P1 to P4 are communicated to the plates by means of coaxial vertical tubes.
  • the coaxial vertical tubes are integral with the plates.
  • the axis of the tubes coincides with the axis A.
  • a coaxial tube rotates a plate to which it is assembled.
  • the tube T1 is assembled to the plate P1
  • the tube T2 is assembled to the plate P2, and so on up to the tube T4 assembled to the plate P4.
  • the coaxial tubes T1 to T4 are cylindrical of revolution and have different diameters as well as different heights.
  • the diameter of the coaxial tubes increases from the smallest plate P4 to the largest P1.
  • the coaxial tube T4 which is assembled in the lower part of the plate P4, has a diameter smaller than the diameter of the coaxial tube T3 and so on.
  • Coaxial tubes T1 to T4 are arranged around the central fuel injection tube 8. The smaller the diameter of a tube, the higher the height. of the tube is large. So the T4 tube is the tallest and the T1 tube is the smallest. As shown in figure 8 , the tubes T1 to T4 are equipped, at their base, with a drive system.
  • This drive system is formed, for example, of toothed wheels 9 driven by a pinion 10, namely a toothed wheel of smaller diameter, fixed to a motor axis 11 parallel to the coaxial tube, actuated by a motor-reduction unit 12. It may however be any other suitable drive system, for example, a similar system comprising an assembly provided with a toothed wheel, a chain, and a motor or piston.
  • having trays with a center of gravity on the axis of rotation allows the use of larger and heavier grids.
  • this characteristic makes it possible to avoid wearing out the mechanical transmission system prematurely while unbalanced plates create a damaging overhang for the entire mechanical strength over time.
  • the fact of having all the movable plates makes it possible to operate the engines for a shorter period of time for the same effect of advancement of the fuel cell. This results in energy savings during operation and limits the wear of mechanical parts.
  • Another advantage of this solution is that the grid is more resilient in the event of a blockage. It can continue to operate with a jammed platter, trays located above and below the locked tray operating independently.
  • the availability of the grid is thus improved and maintenance can be scheduled at the most convenient time.
  • the trays are all removable in portions. This makes it possible to facilitate maintenance operations and to carry them out with a minimum of tools, even for a large diameter grid.
  • the complete slots in the trays and the use of a refractory steel allow the trays to hold up well to temperature and have thinner trays. This confers an economic gain in the manufacture but it also facilitates maintenance with lighter plates to handle.
  • the variable height of the trays makes it possible to overcome the paradox of a circular grid fed by the center.
  • the double primary air circuit makes it possible to inject recirculated fumes or air preheated to a high temperature, for example of the order of 200 ° C, while ensuring the mechanical system is cooled and not polluted by flying dust.
  • the recirculation of flue gases or the preheating of the air are an advantage for reducing the production of NOx and for fuels with a low calorific value.
  • the injection system primary air ensures the distribution of air under the grate and therefore better control of combustion. It also allows the grid to be cooled with the primary air.
  • the drive system based on concentric tubes allows great flexibility in the choice of the drive mechanism used. It can be adapted according to the characteristics of the grate and the fuel.

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  • Engineering & Computer Science (AREA)
  • Chemical & Material Sciences (AREA)
  • Mechanical Engineering (AREA)
  • Combustion & Propulsion (AREA)
  • General Engineering & Computer Science (AREA)
  • Oil, Petroleum & Natural Gas (AREA)
  • Organic Chemistry (AREA)
  • Solid-Fuel Combustion (AREA)

Abstract

L'invention concerne un système (1) de grille de décendrage pour foyer d'une installation de combustion ou de gazéification alimentée en combustible solide, ledit système de grille comprenant un plateau circulaire inférieur (P1) de diamètre D1 et de surface SI monté rotatif à 360° selon un axe de rotation vertical (A), et caractérisé en ce qu'il comprend en outre au moins un plateau supérieur (P2, P3, P4), superposé audit plateau inférieur (P1), et monté rotatif à 360° selon l'axe de rotation vertical (A), ledit au moins un plateau supérieur (P2, P3, P4) ayant une surface S2 inférieure à la surface SI du plateau inférieur (P1) et une dimension maximale au plus égale au diamètre D1 de ce plateau inférieur (P1).The invention relates to an ash grate system (1) for the hearth of a combustion or gasification plant supplied with solid fuel, said grate system comprising a lower circular plate (P1) of diameter D1 and of surface SI mounted to rotate at 360 ° along a vertical axis of rotation (A), and characterized in that it further comprises at least one upper plate (P2, P3, P4), superimposed on said lower plate (P1), and mounted to rotate 360 ° along the vertical axis of rotation (A), said at least one upper plate (P2, P3, P4) having a surface S2 less than the surface SI of the lower plate (P1) and a maximum dimension at most equal to the diameter D1 of this lower plate (P1).

Description

DOMAINE DE L'INVENTIONFIELD OF THE INVENTION

La présente invention concerne un système de grille de décendrage pour foyer d'une installation de combustion ou de gazéification alimentée en combustible solide, ledit système de grille comprenant un plateau circulaire inférieur de diamètre D1 et de surface S1 monté rotatif à 360° selon un axe de rotation vertical A, et une installation comprenant un tel système de grille de décendrage.The present invention relates to an ash grate system for the hearth of a combustion or gasification plant supplied with solid fuel, said grate system comprising a lower circular plate of diameter D1 and of surface S1 mounted to rotate 360 ° along an axis. vertical rotation A, and an installation comprising such an ash grid system.

ART ANTERIEURPRIOR ART

Les installations de combustion ou de gazéification comprennent un foyer à l'intérieur duquel un lit fixe d'un combustible solide, par exemple de la biomasse, est brûlé pour fournir de la chaleur. Elles génèrent également des résidus, tels que des cendres, du char ou divers imbrûlés, qui doivent être évacués en continu hors du foyer, pour éviter des arrêts de fonctionnement. A cet effet, les installations de combustion ou de gazéification selon l'art antérieur sont équipées de systèmes de grille de décendrage.Combustion or gasification plants include a hearth inside which a fixed bed of a solid fuel, for example biomass, is burned to provide heat. They also generate residues, such as ash, char or various unburnt materials, which must be continuously evacuated out of the hearth, to avoid downtime. To this end, the combustion or gasification installations according to the prior art are equipped with ash grid systems.

Les systèmes de grille sont avantageusement prévus pour répondre à différentes problématiques dans les installations de combustion ou de gazéification parmi lesquelles - l'accueil du système d'injection de combustible dans le foyer ; - la mise en mouvement du combustible pour faire avancer le combustible vers le système d'évacuation des cendres, le système d'entrainement devant être adapté à la chaleur et à la présence d'éventuelles poussières, et en être protégé ; - la maîtrise de la vitesse d'avance du lit de combustible pour éviter la formation d'imbrulés (temps de séjour trop court) ou de mâchefers (temps de séjour trop long). Cela doit aussi permettre de faire fonctionner le foyer à différents niveaux de charge ; - la possibilité d'injecter l'air primaire au travers de la grille ; - la maitrise de la distribution de l'air primaire sur différentes portions de la grille pour contrôler la combustion ; - l'évacuation des cendres du foyer au fur et à mesure de la combustion, les plus gros morceaux ne devant pas bloquer cette évacuation ; - la grille doit tenir à des niveaux de température élevées sans déformation ; et - le contrôle de la température et de la vitesse d'évacuation des cendres pour éviter la formation de mâchefer.The grid systems are advantageously designed to respond to various problems in combustion or gasification installations, among which - the reception of the fuel injection system in the home; - the setting in motion of the fuel to advance the fuel towards the ash evacuation system, the drive system having to be adapted to the heat and the presence of any dust, and to be protected; - control of the feed rate of the fuel bed to avoid the formation of unburnt (too short residence time) or bottom ash (too long residence time). This should also allow the fireplace to operate at different load levels; - the possibility of injecting primary air through the grille; - control of the distribution of primary air on different portions of the grate to control combustion; - the evacuation of the ashes from the fireplace as the combustion progresses, the larger pieces not having to block this evacuation; - the grid must withstand high temperature levels without deformation; and - control of the temperature and the speed of ash removal to prevent the formation of clinker.

De nombreux système de grille de décendrage ont été développés pour répondre à certaines ou à l'ensemble des problématiques exposées ci-dessus. Certains systèmes comprennent des grilles vibrantes, d'autres comprennent des grilles rotatives, d'autres encore comprennent des grilles basculantes, et d'autres enfin comprennent des grilles à gradins.Many ash grid systems have been developed to respond to some or all of the issues outlined above. Some systems include vibrating grids, others include rotating grids, still others include tilting grates, and finally others include stepped grates.

RESUME DE L'INVENTIONSUMMARY OF THE INVENTION

Compte tenu de ce qui précède, un problème que se propose de résoudre l'invention est de réaliser un système de grille de décendrage pour foyer d'une installation de combustion ou de gazéification alimentée en combustible solide, qui pallie les problématiques précitées de l'état de la technique. Ce système répond aussi à la variabilité de la composition du combustible, qui nécessite de faire varier les temps de séjour des cendres sur la grille en fonction de la nature des cendres évacuées. Si les cendres qui sortent de la grilles sont agglomérées ou partiellement fondues : le temps de séjour est trop long. Il faut augmenter la vitesse de certains plateaux. Si les cendres contiennent des imbrûlés, il faut rallonger le temps de séjour.In view of the foregoing, a problem which the invention proposes to solve is to provide an ash grid system for the hearth of a combustion or gasification installation supplied with solid fuel, which overcomes the aforementioned problems of state of technique. This system also responds to the variability of the composition of the fuel, which requires varying the residence times of the ash on the grate depending on the nature of the ash evacuated. If the ashes coming out of the grates are agglomerated or partially melted: the residence time is too long. You have to increase the speed of some trays. If the ashes contain unburnt material, the residence time must be extended.

La solution de l'invention à ce problème posé a pour premier objet un système de grille de décendrage pour foyer d'une installation de combustion ou de gazéification alimentée en combustible solide, ledit système de grille comprenant un plateau circulaire inférieur de diamètre D1 et de surface S1 monté rotatif à 360° selon un axe de rotation vertical A, et caractérisé en ce qu'il comprend en outre au moins un plateau supérieur, superposé audit plateau inférieur, et monté rotatif à 360° selon l'axe de rotation vertical A, ledit au moins un plateau supérieur ayant une surface S2 inférieure à la surface S1 du plateau inférieur et une dimension maximale au plus égale au diamètre D1 de ce plateau inférieur, lesdits plateaux étant mobiles, le centre de gravité desdits plateaux (étant sur l'axe de rotation A, le ou les plateaux supérieurs ayant une forme différente de la forme circulaire et une plus grande dimension sensiblement égale à la plus petite dimension du plateau sur lequel ils sont superposés, les plateaux inférieur et supérieur ne tournant pas à la même vitesse.The first object of the solution of the invention to this problem posed is an ash removal grid system for the hearth of a combustion or gasification installation supplied with solid fuel, said grid system comprising a lower circular plate of diameter D1 and of surface S1 mounted to rotate 360 ° along a vertical axis of rotation A, and characterized in that it further comprises at least one upper plate, superimposed on said lower plate, and mounted to rotate 360 ° along the vertical axis of rotation A , said at least one upper plate having a surface S2 less than the surface S1 of the lower plate and a maximum dimension at most equal to the diameter D1 of this lower plate, said plates being movable, the center of gravity of said plates (being on the axis of rotation A, the upper plate (s) having a shape different from the circular shape and a greater dimension substantially equal to the smallest dimension of the plate on which they are superimposed, the lower and upper plates not rotating at the same speed.

De manière avantageuse, - chaque plateau est mobile en rotation selon une vitesse de rotation Vi, cette vitesse de rotation étant variable dans le temps en fonction de la composition du combustible ; - les vitesses de rotation des plateaux supérieurs sont différentes et sont variables de manière individuelle ; - le système comprend une pluralité de plateaux supérieurs superposés les uns aux autres, l'ensemble des plateaux supérieurs étant superposés au plateau inférieur, la surface S2 du plateau immédiatement supérieur au plateau inférieur s'inscrit dans celle S1 dudit plateau inférieur, et la surface S3, et éventuellement la surface S4, du ou des plateaux supérieurs positionnés au-dessus du plateau immédiatement supérieur au plateau inférieur sont décroissantes en fonction de leur position dans la superposition des plateaux ; - les plateaux supérieurs ne se présentent pas sous une forme circulaire ; - le ou les plateaux supérieurs ont une forme elliptique ; - les plateaux sont ajourés ; - les plateaux présentent des fentes et/ou des ouvertures ; - une entrée circulaire de combustible est aménagée au centre de l'empilement des plateaux, le centre de ladite entrée circulaire étant positionné sensiblement sur l'axe A et en ce qu'un tube relié à cette entrée permet l'admission du combustible, verticalement, au travers des plateaux superposés ; - le système comporte deux entrées d'air primaire de deux circuits d'air indépendants, un circuit d'air principal et un circuit d'air de refroidissement ; le système comporte une couronne d'air d'injection autour du plateau inférieur, ladite couronne d'air injectant de l'air radialement sur le plateau inférieur, pour éliminer la présence d'imbrûlés dans les cendres par combustion ; - des tubes cylindriques coaxiaux sont fixés aux plateaux, un tube cylindrique étant fixé à chaque plateau, et en ce que les plateaux sont entraînés en rotation au moyen de ces tubes, qui sont eux-mêmes entrainés en rotation de manière indépendante par des moyens d'entraînement.Advantageously, each plate can be rotated according to a speed of rotation Vi, this speed rotation being variable over time as a function of the composition of the fuel; - the speeds of rotation of the upper plates are different and are variable individually; - the system comprises a plurality of upper plates superimposed on one another, all of the upper plates being superimposed on the lower plate, the surface S2 of the plate immediately above the lower plate is inscribed in that S1 of said lower plate, and the surface S3, and possibly the surface S4, of the upper plate (s) positioned above the plate immediately above the lower plate decrease as a function of their position in the superposition of the plates; - the upper plates are not in a circular shape; the upper plate (s) have an elliptical shape; - the trays are openwork; - the trays have slits and / or openings; a circular fuel inlet is arranged at the center of the stack of trays, the center of said circular inlet being positioned substantially on the axis A and in that a tube connected to this inlet allows the fuel to be admitted vertically , through the superimposed trays; - the system has two primary air inlets of two independent air circuits, a main air circuit and a cooling air circuit; the system comprises a ring of injection air around the lower plate, said ring of air injecting air radially on the lower plate, to eliminate the presence of unburnt material in the ashes by combustion; - coaxial cylindrical tubes are fixed to the plates, a cylindrical tube being fixed to each plate, and in that the plates are driven in rotation by means of these tubes, which are themselves rotated independently by drive means.

Elle a pour second objet, une installation de combustion ou de gazéification alimentée en combustible solide comprenant un système de grille tel que défini ci-dessus.Its second object is a combustion or gasification installation supplied with solid fuel comprising a grid system as defined above.

De manière avantageuse, le combustible a une composition variable.Advantageously, the fuel has a variable composition.

BREVE DESCRIPTION DES FIGURESBRIEF DESCRIPTION OF THE FIGURES

L'invention sera mieux comprise à la lecture de la description non limitative qui suit, rédigée au regard des dessins annexés, dans lesquels :

  • la figure 1 montre, en perspective, un mode de réalisation du système de grille selon l'invention ;
  • la figure 2A est un schéma illustratif d'un premier mode de réalisation d'un plateau supérieur d'un système de grille selon l'invention ;
  • la figure 2B est un schéma illustratif d'un deuxième mode de réalisation d'un plateau supérieur d'un système de grille selon l'invention ;
  • la figure 2C est un schéma illustratif d'un troisième mode de réalisation d'un plateau supérieur d'un système de grille selon l'invention ;
  • la figure 3A est un schéma qui illustre une superposition de deux plateaux supérieurs selon un premier mode de réalisation d'un système de grille selon l'invention ;
  • la figure 3B est un schéma qui illustre une superposition de deux plateaux supérieurs selon un deuxième mode de réalisation d'un système de grille selon l'invention ;
  • la figure 4 est une vue partielle, en perspective, d'un ensemble de plateaux superposés d'un système de grille selon l'invention ;
  • la figure 5 est une vue de dessus, d'un plateau d'un système de grille selon l'invention, montrant les fentes ménagées à l'intérieur ce plateau ;
  • la figure 6A montre, en perspective, la partie inférieure d'un système de grille selon l'invention, et les trappes à ouverture rapide que comporte ce système, pour le nettoyage des circuits d'injections d'air primaire ;
  • la figure 6B montre, en coupe, un système de grille selon l'invention, ainsi que les circuits principal et de refroidissement de ce circuit ;
  • est un schéma illustrant le positionnement des tubes de support des plateaux du système de grille selon l'invention ; et
  • la figure 8 est une vue en perspective et en coupe d'un système de grille selon l'invention, qui montre en particulier le système d'entraînement des plateaux de ce système.
The invention will be better understood on reading the following non-limiting description, drawn up with reference to the appended drawings, in which:
  • the figure 1 shows, in perspective, an embodiment of the grid system according to the invention;
  • the figure 2A is an illustrative diagram of a first embodiment of an upper plate of a grid system according to the invention;
  • the figure 2B is an illustrative diagram of a second embodiment of an upper plate of a grid system according to the invention;
  • the figure 2C is an illustrative diagram of a third embodiment of an upper plate of a grid system according to the invention;
  • the figure 3A is a diagram which illustrates a superposition of two upper plates according to a first embodiment of a grid system according to the invention;
  • the figure 3B is a diagram which illustrates a superposition of two upper plates according to a second embodiment of a grid system according to the invention;
  • the figure 4 is a partial perspective view of a set of superimposed trays of a grid system according to the invention;
  • the figure 5 is a top view of a tray of a grid system according to the invention, showing the slots formed inside this tray;
  • the figure 6A shows, in perspective, the lower part of a grille system according to the invention, and the quick-opening hatches that this system comprises, for cleaning the primary air injection circuits;
  • the figure 6B shows, in section, a grid system according to the invention, as well as the main and cooling circuits of this circuit;
  • is a diagram illustrating the positioning of the support tubes of the trays of the grid system according to the invention; and
  • the figure 8 is a perspective and sectional view of a grid system according to the invention, which shows in particular the system for driving the plates of this system.

DESCRIPTION DETAILLEE DE L'INVENTIONDETAILED DESCRIPTION OF THE INVENTION

De manière générale, une installation de gazéification ou de combustion selon l'invention est destinée à brûler ou gazéifier un combustible solide, notamment issu de la biomasse, en vue d'une production de chaleur.In general, a gasification or combustion installation according to the invention is intended to burn or gasify a solid fuel, in particular derived from biomass, with a view to producing heat.

Le combustible est donc par nature hétérogène. Sa composition est variable. Notamment, il est plus ou moins sec.The fuel is therefore inherently heterogeneous. Its composition is variable. In particular, it is more or less dry.

Une telle installation selon l'invention comprend un foyer qui est ménagé autour d'un axe de symétrie vertical. Ce foyer est délimité par une paroi latérale, par exemple cylindrique. Le combustible est admis dans le foyer par une entrée de combustible en correspondance avec un canal d'approvisionnement en combustible. Ce canal d'approvisionnement est préférentiellement formé d'un tube cylindrique vertical centré sur un ensemble de plateaux tournants superposés formant une grille. Au fur et à mesure de l'admission du combustible solide dans le foyer, verticalement, du bas vers le haut, par le canal d'approvisionnement, jusqu'à l'entrée de combustible, un monticule de combustible solide se forme sur la grille.Such an installation according to the invention comprises a hearth which is arranged around a vertical axis of symmetry. This focus is delimited by a side wall, for example cylindrical. The fuel is admitted into the furnace through a fuel inlet in correspondence with a fuel supply channel. This supply channel is preferably formed of a vertical cylindrical tube centered on a set of superimposed turntables forming a grid. As the solid fuel enters the fireplace, vertically, from bottom to top, through the supply channel, to the fuel inlet, a mound of solid fuel forms on the grate .

Ainsi que cela est montré à la figure 1, le système de grille 1 comprend un plateau inférieur P1 et un ou plusieurs plateaux supérieurs. En pratique, le nombre de plateaux supérieurs est avantageusement de deux ou de trois. Dans l'exemple de la figure 1, le système 1 comprend trois plateaux supérieurs P2, P3 et P4.As shown in figure 1 , the grid system 1 comprises a lower plate P1 and one or more upper plates. In practice, the number of upper plates is advantageously two or three. In the example of figure 1 , system 1 comprises three upper plates P2, P3 and P4.

Le ou les plateaux supérieurs P2 à P4 sont positionnés sur le plateau inférieur P1, empilés sur ce plateau P1. Tous les plateaux P1 à P4 sont des plateaux tournants, montés mobiles en rotation autour d'un axe vertical A selon un angle de 360°. Le plateau inférieur P1 est monté sur une embase circulaire fixe 2.The upper plate (s) P2 to P4 are positioned on the lower plate P1, stacked on this plate P1. All the plates P1 to P4 are rotating plates, mounted to be able to rotate about a vertical axis A at an angle of 360 °. The lower plate P1 is mounted on a fixed circular base 2.

Le plateau inférieur P1 est circulaire de diamètre D. Il s'agit du plus grand des plateaux. La surface du plateau supérieur P1 est égale à S1 (S=π(D/2)2)). La surface des plateaux supérieurs S2, S3, S4 est inférieure à S1. Ces surfaces S2, S3 et S4 sont décroissantes : S2 > S3 > S4.The lower plate P1 is circular with a diameter D. It is the largest of the plates. The surface of the upper plate P1 is equal to S1 (S = π (D / 2) 2 )). The surface of the upper plates S2, S3, S4 is less than S1. These surfaces S2, S3 and S4 are decreasing: S2>S3> S4.

Avantageusement, les plateaux supérieurs ne sont pas circulaires. Des exemples de formes de ces plateaux supérieurs sont montrés aux figures 2A, 2B et 2C. A la figure 2A, les plateaux P2 à P4 se présentent sous une forme elliptique. A la figure 2B ils sont triangulaires. A la figure 2C, ils sont en étoile. Bien entendu, d'autres conformations des plateaux supérieurs sont possibles et notamment, une conformation ellipsoïdale. Compte tenu qu'ils ne sont pas circulaires, les plateaux supérieurs P2 à P4 présentent au moins une plus grande dimension et des dimensions plus petites. La plus grande dimension du plateau supérieur P2 positionné immédiatement au-dessus du plateau inférieur P1 est égale ou approximativement égale au diamètre D du plateau inférieur P1. La surface S2 du plateau supérieur P2 est inférieure à celle S1 du plateau inférieur. Les figures 3A et 3B présentent une superposition de deux plateaux supérieurs, par exemple les plateaux P2 et P3, le plateau P3 étant superposé sur le plateau P2. A la figure 3A, les plateaux P2 et P3 sont en ellipse. Il présentent donc chacun une plus grande dimension, à savoir le grand axe de l'ellipse, et une plus petite dimension : le petit axe de cet ellipse. Le grand axe de l'ellipse que forme le plateau P3 est approximativement égal ou égal au petit axe de l'ellipse que forme le plateau P2. A la figure 3B, les plateaux P2 et P3 sont triangulaires et les triangles qu'ils définissent sont équilatéraux. Dans ce cas aussi, la plus grande dimension du triangle formant P3, à savoir le côté de ce triangle, est approximativement égale à la plus petite dimension que définit du triangle formant P2. En définitive, on notera que le plateau P3 s'inscrit dans le plateau P2 avec une plus grande dimension, pour P3 égale ou approximativement égale à la plus petite dimension de P2. Les caractéristiques précitées des plateaux P2 et P3 s'appliquent de la même manière aux plateaux P3 et P4 et ainsi de suite.Advantageously, the upper plates are not circular. Examples of the shapes of these top trays are shown at figures 2A, 2B and 2C . To the figure 2A , the plates P2 to P4 are in an elliptical shape. To the figure 2B they are triangular. To the figure 2C , they are in a star. Of course, other conformations of the upper plates are possible and in particular an ellipsoidal conformation. Given that they are not circular, the upper plates P2 to P4 have at least one larger dimension and smaller dimensions. The largest dimension of the upper plate P2 positioned immediately above the lower plate P1 is equal or approximately equal to the diameter D of the lower plate P1. The surface S2 of the upper plate P2 is less than that S1 of the lower plate. The figures 3A and 3B have a superposition of two upper plates, for example the plates P2 and P3, the plate P3 being superimposed on the plate P2. To the figure 3A , the plates P2 and P3 are elliptical. They therefore each have a greater dimension, namely the major axis of the ellipse, and a smaller dimension: the minor axis of this ellipse. The major axis of the ellipse formed by plate P3 is approximately equal to or equal to the minor axis of the ellipse formed by plate P2. To the figure 3B , the plates P2 and P3 are triangular and the triangles they define are equilateral. In this case also, the largest dimension of the triangle forming P3, namely the side of this triangle, is approximately equal to the smallest dimension defined by the triangle forming P2. Finally, it will be noted that the plate P3 fits into the plate P2 with a greater dimension, for P3 equal or approximately equal to the smallest dimension of P2. The aforementioned characteristics of the plates P2 and P3 apply in the same way to the plates P3 and P4 and so on.

On notera que la forme du ou des plateaux supérieurs peut être diverse du moment qu'il rassemble les caractéristiques suivantes. Tout d'abord, le centre de gravité des plateaux est sur l'axe de rotation. Cela permet d'éviter d'avoir des efforts mécaniques répartis de manière non symétrique sur les supports du plateau. Cela permet d'améliorer la durée de vie du système. De plus, cela permet de couvrir et découvrir alternativement la surface du plateau inférieur lors de la rotation. Cela permet de « racler » la surface d'un plateau inférieur par un plateau supérieur et ainsi de faire avancer le combustible vers le pourtour du réacteur.It will be noted that the shape of the upper plate (s) can be diverse as long as it combines the following characteristics. First of all, the center of gravity of the platters is on the axis of rotation. This makes it possible to avoid having mechanical forces distributed in a non-symmetrical manner on the supports of the plate. This improves the life of the system. In addition, this makes it possible to alternately cover and uncover the surface of the lower plate during the rotation. This makes it possible to "scrape" the surface of a lower plate by an upper plate and thus to advance the fuel towards the periphery of the reactor.

L'épaisseur des plateaux P1, P2, P3, P4 est croissante dans l'empilement desdits plateaux dans le système de grille. Plus le plateau est positionné en hauteur dans cet empilement, plus son épaisseur est importante. Par exemple, le plateau inférieur P1 a une épaisseur de 100 mm, celle du plateau supérieur P2 qui lui est immédiatement supérieur a une épaisseur de 80 mm, celle du plateau P3 est de 60 mm et celle du plateau P4 est de 60 mm. Cela permet d'entrainer une quantité équivalente de combustible pour chaque plateau.The thickness of the plates P1, P2, P3, P4 increases in the stacking of said plates in the grid system. The higher the tray is positioned in this stack, the greater its thickness. For example, the lower plate P1 has a thickness of 100 mm, that of the upper plate P2 which is immediately above it has a thickness of 80 mm, that of the plate P3 is 60 mm and that of the plate P4 is 60 mm. This allows to train an equivalent amount of fuel for each tray.

Les plateaux P1 à P4 sont réalisés de sorte qu'ils soient démontables par portion pour faciliter les opérations de maintenance et d'installation. Cela permet aussi d'optimiser le cout de maintenance en ne remplaçant que la portion d'un plateau abimé et pas l'ensemble du plateau.Trays P1 to P4 are made so that they can be dismantled by portion to facilitate maintenance and installation operations. It also allows to optimize the maintenance cost by replacing only the portion of a damaged plate and not the entire plate.

Ainsi que cela est montré à la figure 5, les plateaux P1 à P4 sont ajourés de sorte que l'air primaire puisse passer au travers desdits plateaux. A cet effet, les plateaux présentent par exemple des trous ou des fentes. Dans la configuration préférentielle de la figure 5, ils sont munis de fentes sensiblement radiales, à savoir partant de la périphérie des plateaux et allant vers le centre de ceux-ci. Certaines fentes F1 ne sont pas complètes et ne se prolongent pas jusqu'au périmètre des plateaux. D'autres fentes F2 sont complètes et se prolongent jusqu'à la périphérie des plateaux. Elles permettent aux plateaux de se dilater sans créer de distorsion. Les fentes F1, F2 se prolongent avantageusement, du côté du centre des plateaux, par des ouvertures O plus larges que les fentes F1, F2. Ces ouvertures O laissent passer l'air et évitent la formation de microfissures au niveau des fentes F1, F2. Les fentes F1, F2 peuvent ne pas être strictement positionnées radialement sur les plateaux. Autrement dit, elles peuvent ne pas passer par le centre de ceux-ci. Elles sont alors légèrement inclinées de sorte que, pour un même nombre de fentes, la surface permettant le passage de l'air soit plus important. En outre, cela améliore la solidité des plateaux. Par ailleurs, les surfaces de fentes sont calculées de façon à optimiser les débits d'air et par là-même le profil de combustion/gazéification du combustible solide, au niveau de chaque plateau. Enfin, la section des fentes est calculée de façon à créer une perte de charge déterminée de l'air les traversant, assurant un débit homogène par fente, indépendant de la quantité locale de combustible située au-dessus, et évitant en particulier des fuites d'air incontrôlées en cas de manque de combustible au-dessus des fentes.As shown in figure 5 , the plates P1 to P4 are perforated so that the primary air can pass through said plates. To this end, the plates have, for example, holes or slits. In the preferential configuration of the figure 5 , they are provided with substantially radial slots, namely starting from the periphery of the plates and going towards the center thereof. Some F1 slots are not complete and do not extend to the perimeter of the chainrings. Other F2 slots are complete and extend to the periphery of the trays. They allow the platters to expand without creating distortion. The slots F1, F2 advantageously extend, on the side of the center of the plates, by openings O that are wider than the slots F1, F2. These openings O allow air to pass and prevent the formation of microcracks at the level of the slots F1, F2. The slots F1, F2 may not be strictly positioned radially on the plates. In other words, they may not pass through the center of these. They are then slightly inclined so that, for the same number of slots, the surface allowing the passage of air is greater. In addition, it improves the strength of the chainrings. Furthermore, the slot surfaces are calculated so as to optimize the air flow rates and thereby the combustion / gasification profile of the solid fuel, at each plate. Finally, the section of the slots is calculated so as to create a determined pressure drop of the air passing through them, ensuring a homogeneous flow rate per slot, independent of the local quantity of fuel located above, and in particular avoiding uncontrolled air leaks if there is a lack of fuel above the slots.

Si l'on se réfère de nouveau à la figure 1, il apparaît qu'une entrée de combustible circulaire 3 est aménagée au centre des plateaux P1 à P4 du système de grille 1. Tous les plateaux P1 à P4 peuvent tourner autour de l'axe de rotation A, identique à l'axe de révolution de l'entrée de combustible 3. Le mouvement de rotation d'un plateau donné crée un mouvement relatif par rapport aux plateaux situés au-dessus et au-dessous et la forme elliptique, ou autre, des plateaux supérieurs P2 à P4, ce qui permet de balayer la surface des plateaux sur lesquels ils sont superposés et de faire avancer le combustible vers l'extérieur.If we refer again to the figure 1 , it appears that a circular fuel inlet 3 is arranged in the center of the plates P1 to P4 of the grid system 1. All the plates P1 to P4 can rotate around the axis of rotation A, identical to the axis of revolution of the fuel inlet 3. The rotational movement of a given platen creates a relative motion with respect to the platens above and below and the elliptical shape, or the like, of the upper platens P2 to P4, which makes it possible to sweep the surface of the trays on which they are superimposed and to advance the fuel towards the outside.

Les plateaux P1 à P4 ne tournent pas en même temps et à la même vitesse de telle sorte qu'il y ait un mouvement relatif entre les plateaux. Autrement dit, chacun des plateaux P1 à P4 tourne à une vitesse différente. Par ailleurs chacun des plateaux peut tourner à une vitesse variable pour ajuster le temps de séjour des cendres qui doit être variable en fonction de la nature des cendres. Les vitesses de rotation des plateaux sont réglables indépendamment les unes des autres. Elles sont contrôlées de manière indépendantes. Elles varient dans le temps de manière indépendante. On peut avoir des vitesses différentes pour chaque plateau.Plates P1 to P4 do not rotate at the same time and at the same speed so that there is relative movement between the platters. In other words, each of the plates P1 to P4 rotates at a different speed. Furthermore, each of the plates can turn at a variable speed to adjust the ash residence time which must be variable depending on the nature of the ash. The rotational speeds of the plates are adjustable independently of each other. They are independently controlled. They vary over time independently. We can have different speeds for each plate.

A noter que dans l'invention, les plateaux tournent à vitesse variable en fonction de la nature du combustible utilisé. Le fait que les plateaux puissent faire varier leur vitesse, permet de faire varier le temps de séjour dans le gazéifieur, en fonction de la nature du combustible et des cendres. Un temps de séjour trop long peut impliquer la fusion des cendres et donc le blocage, voire la destruction de la grille. Un taux de séjour trop court conduit à la présence d'imbrûlés au bas de la grille, ce qui diminue le rendement de l'installation et augmente le risque de blocage. Avec des déchets, par nature de composition variable, seule une grille avec vitesse de rotation variable peut fonctionner. En conclusion, la grille selon l'invention est la seule qui puisse s'adapter à une composition de déchets variable au fil du temps.Note that in the invention, the plates rotate at variable speed depending on the nature of the fuel used. The fact that the plates can vary their speed makes it possible to vary the residence time in the gasifier, depending on the nature of the fuel. and ashes. Too long a residence time may involve melting the ash and therefore blocking or even destroying the grate. Too short a stay rate leads to the presence of unburnt substances at the bottom of the grid, which reduces the efficiency of the installation and increases the risk of blockage. With waste, by nature of variable composition, only a grid with variable speed of rotation can operate. In conclusion, the grid according to the invention is the only one which can adapt to a composition of waste that varies over time.

Une large fente 4 est aménagée sur le pourtour de la grille pour évacuer les cendres. Les cendres sont ainsi évacuées en continu du foyer au travers de cette fente 4.A large slit 4 is fitted around the perimeter of the grate to evacuate the ashes. The ashes are thus continuously evacuated from the hearth through this slot 4.

Le système de grille selon l'invention est aussi conçu pour ne pas créer de point d'accumulation de cendres indésirables.The grid system according to the invention is also designed so as not to create any point of accumulation of undesirable ash.

Les plateaux ont pour fonction d'étaler le combustible et d'amener les cendres vers l'extérieur, à savoir vers la large fente 4, afin de les évacuer. Le fait que tous les plateaux soient mobiles a deux avantages par rapport à des systèmes avec plateaux fixes. Tout d'abord, un seul plateau en mouvement permet de balayer le combustible du plateau mobile plus le combustible sur le plateau inférieur. On a donc moins besoin de faire tourner les moteurs pour le même service. On économise de l'énergie. De plus, le système est moins sensible aux éventuels blocages. Si un plateau est bloqué pour une raison quelconque, les plateaux au-dessus et au-dessous peuvent être utilisés pour continuer de faire fonctionner la grille, et donc l'unité de production d'énergie, le temps de planifier et de réaliser une opération de maintenance au moment le plus propice. La disponibilité du système de grille et la flexibilité vis-à-vis de la réparation sont plus élevées.The function of the trays is to spread the fuel and bring the ashes to the outside, namely towards the wide slit 4, in order to evacuate them. The fact that all the trays are movable has two advantages over systems with fixed trays. First, a single moving platen sweeps the fuel from the movable platen plus the fuel on the lower platen. There is therefore less need to run the engines for the same service. We save energy. In addition, the system is less sensitive to possible blockages. If a tray gets stuck for some reason, the trays above and below can be used to continue operating the grid, and therefore the power generation unit, time to plan and carry out a maintenance operation at the most convenient time. The availability of the grid system and the flexibility to repair is higher.

L'évacuation des cendres présentes dans le foyer se fait par la large fente ou gorge 4 positionnée sur tout le pourtour du système de grille. Les cendres tombent par cette fente sur un système de convoyage non représenté sur les figures, qui permet d'amener les cendres dans un espace de stockage. Cette large fente 4 est réalisée de sorte que les plus gros morceaux pouvant être injectés dans le foyer puissent en être évacués. La majorité des cendres est poussée par les plateaux rotatifs vers l'extérieur de la grille et donc vers cette fente 4. Cependant, des cendres de petites dimensions peuvent aussi être amenées sous les plateaux. A terme, ces cendres de petites dimensions sont susceptibles de bloquer ou de perturber l'écoulement de l'air primaire. Pour éviter ce phénomène, des dispositifs de raclage sont aménagés sous les plateaux. Ces dispositifs ne sont pas représentés dans les figures. Ils sont orientés de telle sorte que les cendres soient poussées vers l'extérieur de chaque plateau, puis collectées sur le plateau inférieur, jusqu'au plateau P1, où les cendres seront alors poussées vers la fente 4. Une ou plusieurs ouvertures peuvent en outre être ménagées en un point du pourtour du ou des plateaux de telle sorte que les cendres tombent dans la gorge. La section de l'ouverture est calculée précisément de façon à ne pas avoir une fuite d'air préférentielle, qui pourrait affecter le débit d'air principal transitant par les fentes.The ash present in the hearth is evacuated through the wide slit or groove 4 positioned around the entire periphery of the grate system. The ashes fall through this slot onto a conveyor system, not shown in the figures, which allows the ashes to be brought into a storage space. This wide slot 4 is made so that the larger pieces that can be injected into the hearth can be removed therefrom. The majority of the ashes are pushed by the rotating plates towards the outside of the grate and therefore towards this slot 4. However, ash of small dimensions can also be brought under the plates. Ultimately, these small-sized ashes are likely to block or disrupt the flow of primary air. To avoid this phenomenon, scraping devices are fitted under the trays. These devices are not shown in the figures. They are oriented so that the ashes are pushed out of each tray, then collected on the lower tray, up to the tray P1, where the ashes will then be pushed towards the slot 4. One or more openings can also be made at a point around the perimeter of the tray (s) so that the ashes fall into the throat. The section of the opening is calculated precisely so as not to have a preferential air leak, which could affect the main air flow passing through the slots.

Un système d'injection permet d'alimenter le foyer en air primaire à partir de deux entrées d'air indépendantes dans le système. Ces entrées sont référencées 5 et 6 aux figures 6A et 6B. Ces entrées 5 et 6 sont des entrées d'air primaire de deux circuits d'air indépendants : le circuit C1 d'air de refroidissement et le circuit C2 principal. Le circuit C1 d'air de refroidissement permet de faire passer de l'air atmosphérique au travers du système de mise en rotation du système et de le refroidir pour le préserver de dégradations dues à une montée de la température. L'air primaire admis dans l'entrée 5 permet ainsi de refroidir le système mécanique de transmission de mouvement pour en préserver l'intégrité. Cet air permet aussi d'éviter toute intrusion de poussières de cendres dans la partie mécanique du système selon l'invention. Une partie de cet air primaire est injectée par cette entrée 5 et débouche au niveau de chaque plateau, via un jeu de lumières dédiées, aménagées dans chaque tube coaxial. L'air injecté rejoint ensuite le circuit sous les plateaux du système de grille, avant d'entrer dans le lit de combustible solide. Le second circuit C2 principal permet à la majeure partie du débit d'air primaire d'être injecté dans le foyer au travers de la grille. Ce circuit est indépendant du circuit de refroidissement et n'est pas en contact avec des parties mécaniques sensibles. Cela permet d'injecter de l'air préchauffé ou directement de faire recirculer des fumées pouvant atteindre 200 °C et être chargées en poussières. L'air admis dans l'entrée 6 alimente donc le foyer au travers de la grille. Son débit est maitrisé. Le circuit correspondant à cette entrée n'est jamais en contact avec des éléments sensibles à la température ou à la poussière. Cela permet le cas échéant d'injecter d'autres gaz tels que des fumées recirculées qui contiennent encore des cendres volantes et peuvent atteindre 200 °C. Un troisième circuit d'air est composé d'une couronne d'air notée CA en Fig. 1 d'injection située en périphérie de la grille du bas (le plateau inférieur). Il permet de finaliser la combustion d'éventuels imbrûlés sur la grille du bas. La recirculation des fumées permet d'optimiser la combustion des combustibles très secs et volatils et de diminuer la production de polluants atmosphériques tels que les NOx.An injection system is used to supply the combustion chamber with primary air from two independent air inlets in the the system. These entries are referenced 5 and 6 in figures 6A and 6B . These inlets 5 and 6 are primary air inlets of two independent air circuits: the cooling air circuit C1 and the main circuit C2. The cooling air circuit C1 allows atmospheric air to pass through the system for rotating the system and to cool it to protect it from degradation due to a rise in temperature. The primary air admitted into the inlet 5 thus makes it possible to cool the mechanical movement transmission system in order to preserve its integrity. This air also makes it possible to avoid any intrusion of ash dust into the mechanical part of the system according to the invention. Part of this primary air is injected through this inlet 5 and emerges at the level of each plate, via a set of dedicated lights, arranged in each coaxial tube. The injected air then joins the circuit under the trays of the grate system, before entering the solid fuel bed. The second main circuit C2 allows most of the primary air flow to be injected into the fireplace through the grille. This circuit is independent of the cooling circuit and is not in contact with sensitive mechanical parts. This makes it possible to inject preheated air or directly recirculate fumes of up to 200 ° C and be loaded with dust. The air admitted into the inlet 6 therefore feeds the fireplace through the grille. Its flow is controlled. The circuit corresponding to this input is never in contact with elements sensitive to temperature or dust. This makes it possible, if necessary, to inject other gases such as recirculated fumes which still contain fly ash and can reach 200 ° C. A third air circuit is composed of an air ring denoted CA in Fig. 1 injection valve located on the periphery of the lower grille (the lower plate). It is used to finalize the combustion of any unburnt material on the lower grate. Flue gas recirculation optimizes the combustion of very dry and volatile fuels and reduces the production of atmospheric pollutants such as NOx.

Ainsi que cela est monté à la figure 6, des trappes à ouverture rapide 7 sont avantageusement aménagées sur le circuit d'air primaire sous le système de grille. Elles permettent d'évacuer rapidement les conduites des circuits d'admission d'air en cas d'accumulation de cendres.As well as this ascended to the figure 6 , quick-opening hatches 7 are advantageously arranged on the primary air circuit under the grid system. They allow the pipes of the air intake circuits to be quickly evacuated in the event of an accumulation of ash.

Ainsi que cela est plus particulièrement montré aux figures 7 et 8, les mouvements de rotation des plateaux P1 à P4 sont communiqués aux plateaux au moyen de tubes verticaux coaxiaux. Les tubes verticaux coaxiaux sont solidaires des plateaux. L'axe des tubes est confondu avec l'axe A. Dans le cas d'un système de grille comprenant quatre plateaux P1 à P4, il y a quatre tubes coaxiaux T1, T2, T3 et T4. Un tube coaxial entraîne en rotation un plateau auquel il est assemblé. Le tube T1 est assemblé au plateau P1, le tube T2 est assemblé au plateau P2, et ainsi de suite jusqu'au tube T4 assemblé au plateau P4. Les tubes coaxiaux T1 à T4 sont cylindriques de révolution et présentent des diamètres différents ainsi que des hauteurs différentes. Le diamètre des tubes coaxiaux augmente en partant du plus petit plateau P4 vers le plus grand P1. Le tube coaxial T4, qui est assemblé en partie inférieure du plateau P4, a un diamètre plus petit que le diamètre du tube coaxial T3 et ainsi de suite. Les tubes coaxiaux T1 à T4 sont disposés autour du tube central d'injection de combustible 8. Plus le diamètre d'un tube est petit, plus la hauteur du tube est grande. Ainsi, le tube T4 est le plus haut et le tube T1 est le plus petit. Ainsi que cela est montré à la figure 8, les tubes T1 à T4 sont équipés, à leur base, d'un système d'entrainement. Ce système d'entraînement est formé par exemple de roues dentées 9 entraînées par un pignon 10, à savoir une roue dentée de plus faible diamètre, fixé à un axe moteur 11 parallèle au tube coaxial, actionné par un groupe moto-réducteur 12. Il peut toutefois s'agir de tout autre système d'entrainement adéquat, par exemple, un système similaire comprenant un ensemble muni d'une roue dentée, d'une chaîne, et d'un moteur ou piston.As is more particularly shown to figures 7 and 8 , the rotational movements of the plates P1 to P4 are communicated to the plates by means of coaxial vertical tubes. The coaxial vertical tubes are integral with the plates. The axis of the tubes coincides with the axis A. In the case of a grid system comprising four plates P1 to P4, there are four coaxial tubes T1, T2, T3 and T4. A coaxial tube rotates a plate to which it is assembled. The tube T1 is assembled to the plate P1, the tube T2 is assembled to the plate P2, and so on up to the tube T4 assembled to the plate P4. The coaxial tubes T1 to T4 are cylindrical of revolution and have different diameters as well as different heights. The diameter of the coaxial tubes increases from the smallest plate P4 to the largest P1. The coaxial tube T4, which is assembled in the lower part of the plate P4, has a diameter smaller than the diameter of the coaxial tube T3 and so on. Coaxial tubes T1 to T4 are arranged around the central fuel injection tube 8. The smaller the diameter of a tube, the higher the height. of the tube is large. So the T4 tube is the tallest and the T1 tube is the smallest. As shown in figure 8 , the tubes T1 to T4 are equipped, at their base, with a drive system. This drive system is formed, for example, of toothed wheels 9 driven by a pinion 10, namely a toothed wheel of smaller diameter, fixed to a motor axis 11 parallel to the coaxial tube, actuated by a motor-reduction unit 12. It may however be any other suitable drive system, for example, a similar system comprising an assembly provided with a toothed wheel, a chain, and a motor or piston.

En définitive, le système selon l'invention présente de nombreux avantages.Ultimately, the system according to the invention has many advantages.

Des premiers avantages découlent de la forme et de la conception des plateaux formant la grille du système de grille selon l'invention. Tout d'abord, le fait d'avoir des plateaux avec un centre de gravité sur l'axe de rotation permet d'utiliser des grilles plus grandes et plus lourdes. En effet, cette caractéristique permet d'éviter d'user le système de transmission mécanique de manière prématurée alors que des plateaux non équilibrés créent un porte-à-faux dommageable pour l'ensemble de la tenue mécanique dans le temps. Ensuite, le fait d'avoir tous les plateaux mobiles permet de faire fonctionner les moteurs moins longtemps pour un même effet d'avancement de la pile de combustible. Cela engendre des économies d'énergie pendant le fonctionnement et limite l'usure des pièces mécaniques. Un autre avantage de cette solution est que la grille est plus résiliente en cas de blocage. Elle peut continuer de fonctionner avec un plateau bloqué, les plateaux situés dessus et dessous le plateau bloqué fonctionnant de manière indépendante. La disponibilité de la grille est ainsi améliorée et la maintenance peut-être planifiée au moment le plus propice. Ensuite encore, les plateaux sont tous démontables par portions. Cela permet de faciliter les opérations de maintenance et de les réaliser avec un minimum d'outils même pour une grille de grand diamètre. Par ailleurs, les fentes complètes dans les plateaux et l'utilisation d'un acier réfractaire permettent une bonne tenue des plateaux à la température et d'avoir des plateaux plus fins. Cela confère un gain économique à la fabrication mais cela facilite aussi la maintenance avec des plateaux plus légers à manipuler. Enfin, La hauteur variable des plateaux permet de s'affranchir du paradoxe d'une grille circulaire alimentée par le centre. En effet, sur ce type de grille on a beaucoup de matière au centre (combustible non brulé) mais peu de surface alors que sur l'extérieur de la grille il y a beaucoup moins de matière (cendres) mais une surface de grille plus importante. La hauteur variable des plateaux permet de compenser ce phénomène et de mieux maitriser la combustion.First advantages arise from the shape and design of the plates forming the grid of the grid system according to the invention. First of all, having trays with a center of gravity on the axis of rotation allows the use of larger and heavier grids. In fact, this characteristic makes it possible to avoid wearing out the mechanical transmission system prematurely while unbalanced plates create a damaging overhang for the entire mechanical strength over time. Then, the fact of having all the movable plates makes it possible to operate the engines for a shorter period of time for the same effect of advancement of the fuel cell. This results in energy savings during operation and limits the wear of mechanical parts. Another advantage of this solution is that the grid is more resilient in the event of a blockage. It can continue to operate with a jammed platter, trays located above and below the locked tray operating independently. The availability of the grid is thus improved and maintenance can be scheduled at the most convenient time. Then again, the trays are all removable in portions. This makes it possible to facilitate maintenance operations and to carry them out with a minimum of tools, even for a large diameter grid. Furthermore, the complete slots in the trays and the use of a refractory steel allow the trays to hold up well to temperature and have thinner trays. This confers an economic gain in the manufacture but it also facilitates maintenance with lighter plates to handle. Finally, the variable height of the trays makes it possible to overcome the paradox of a circular grid fed by the center. Indeed, on this type of grate there is a lot of material in the center (unburned fuel) but little surface area while on the outside of the grate there is much less material (ash) but a larger grate surface. . The variable height of the trays makes it possible to compensate for this phenomenon and to better control combustion.

Des deuxièmes avantages découlent du système d'injection d'air primaire selon le système de l'invention. Tout d'abord, le double circuit d'air primaire permet d'injecter des fumées recirculées ou de l'air préchauffé à une température élevée, par exemple de l'ordre de 200 °C, tout en assurant au système mécanique d'être refroidi et non pollué par des poussières volantes. La recirculation de fumées ou le préchauffage de l'air sont un avantage pour diminuer la production de NOx et pour les combustibles à bas Pouvoir Calorifique. Ensuite, le système d'injection d'air primaire permet d'assurer la distribution de l'air sous la grille et donc de mieux maitriser la combustion. Il permet aussi de refroidir la grille avec l'air primaire.Second advantages result from the primary air injection system according to the system of the invention. First of all, the double primary air circuit makes it possible to inject recirculated fumes or air preheated to a high temperature, for example of the order of 200 ° C, while ensuring the mechanical system is cooled and not polluted by flying dust. The recirculation of flue gases or the preheating of the air are an advantage for reducing the production of NOx and for fuels with a low calorific value. Then the injection system primary air ensures the distribution of air under the grate and therefore better control of combustion. It also allows the grid to be cooled with the primary air.

Des troisièmes avantages découlent de la gestion de l'évacuation des cendres selon le système de l'invention. Tout d'abord, la gorge d'évacuation des cendres sur tout le pourtour de la grille est large et permet d'évacuer la totalité des intrants solides ou des mâchefer produits. Ensuite, le système de racleurs sous les plateaux permet d'évacuer les éventuelles petites particules de cendres qui se glisseraient sous les plateaux de manière continue. Cela permet de prévenir des blocages mécaniques ou des bouchages d'injection de l'air.Third advantages result from the management of the evacuation of the ashes according to the system of the invention. First of all, the ash evacuation throat around the entire perimeter of the grate is wide and allows all of the solid inputs or clinker produced to be evacuated. Then, the system of scrapers under the trays makes it possible to evacuate any small particles of ash which would slip under the trays continuously. This helps prevent mechanical blockages or air injection blockages.

Des quatrièmes avantages découlent de la conception du système d'entraînement du système de grille selon l'invention. Le système d'entraînement basé sur des tubes concentriques permet une grande flexibilité pour le choix du mécanisme d'entraînement utilisé. Il peut être adapté en fonction des caractéristiques de la grille et du combustible.Fourth advantages arise from the design of the drive system of the grid system according to the invention. The drive system based on concentric tubes allows great flexibility in the choice of the drive mechanism used. It can be adapted according to the characteristics of the grate and the fuel.

Claims (15)

Système (1) de grille de décendrage pour foyer d'une installation de combustion ou de gazéification alimentée en combustible solide, ledit système de grille comprenant un plateau circulaire inférieur (P1) de diamètre D1 et de surface S1 monté rotatif à 360° selon un axe de rotation vertical (A), et caractérisé en ce qu'il comprend en outre au moins un plateau supérieur (P2, P3, P4), superposé audit plateau inférieur (P1), et monté rotatif à 360° selon l'axe de rotation vertical (A), ledit au moins un plateau supérieur (P2, P3, P4) ayant une surface S2 inférieure à la surface S1 du plateau inférieur (P1) et une dimension maximale au plus égale au diamètre D1 de ce plateau inférieur (P1), lesdits plateaux (P1, P2, P3, P4) étant mobiles, le centre de gravité desdits plateaux (P1, P2, P3, P4) étant sur l'axe de rotation (A), le ou les plateaux supérieurs (P2, P3, P4) ayant une forme différente de la forme circulaire et une plus grande dimension sensiblement égale à la plus petite dimension du plateau sur lequel ils sont superposés, les plateaux inférieur (P1) et supérieur (P2, P3, P4) ne tournant pas à la même vitesse.System (1) of an ash grate for the hearth of a combustion or gasification installation supplied with solid fuel, said grate system comprising a lower circular plate (P1) of diameter D1 and of surface S1 mounted to rotate 360 ° according to a vertical axis of rotation (A), and characterized in that it further comprises at least one upper plate (P2, P3, P4), superimposed on said lower plate (P1), and mounted to rotate 360 ° along the axis of vertical rotation (A), said at least one upper plate (P2, P3, P4) having a surface S2 less than the surface S1 of the lower plate (P1) and a maximum dimension at most equal to the diameter D1 of this lower plate (P1 ), said plates (P1, P2, P3, P4) being movable, the center of gravity of said plates (P1, P2, P3, P4) being on the axis of rotation (A), the upper plate or plates (P2, P3, P4) having a shape different from the circular shape and a larger dimension substantially equal to the smaller dimension n of the plate on which they are superimposed, the lower (P1) and upper (P2, P3, P4) plates not rotating at the same speed. Système (1) selon la revendication 1, caractérisé en ce que chaque plateau (P1, P2, P3, P4) est mobile en rotation selon une vitesse de rotation Vi, cette vitesse de rotation étant variable dans le temps en fonction de la composition du combustible.System (1) according to claim 1, characterized in that each plate (P1, P2, P3, P4) is rotatable according to a rotational speed Vi, this rotational speed being variable over time depending on the composition of the combustible. Système (1) selon l'une des revendications 1 ou 2, caractérisé en ce que les vitesses de rotation des plateaux supérieurs sont différentes et sont variables de manière individuelle.System (1) according to one of claims 1 or 2, characterized in that the rotational speeds of the plates are different and are individually variable. Système (1) selon l'une des revendications précédentes, caractérisé en ce qu'il comprend une pluralité de plateaux supérieurs (P2, P3, P4) superposés les uns aux autres, l'ensemble des plateaux supérieurs (P2, P3, P4) étant superposés au plateau inférieur (P1), en ce que la surface S2 du plateau immédiatement supérieur (P2) au plateau inférieur (P1) s'inscrit dans celle S1 dudit plateau inférieur, et en ce que la surface S3 et, éventuellement la surface S4, du ou des plateaux supérieurs (P3, P4) positionnés au-dessus du plateau (P2) immédiatement supérieur au plateau inférieur (P1) sont décroissantes en fonction de leur position dans la superposition des plateaux.System (1) according to one of the preceding claims, characterized in that it comprises a plurality of upper plates (P2, P3, P4) superimposed on one another, the set of upper plates (P2, P3, P4) being superimposed on the lower plate (P1), in that the surface S2 of the plate immediately upper (P2) to the lower plate (P1) is inscribed in that S1 of said lower plate, and in that the surface S3 and, optionally the surface S4, of the upper plate (s) (P3, P4) positioned above the plate (P2) immediately above the lower plate (P1) are decreasing according to their position in the superposition of the plates. Système (1) selon l'une des revendications précédentes, caractérisé en ce que les plateaux supérieurs (P2, P3, P4) ne se présentent pas sous une forme circulaire.System (1) according to one of the preceding claims, characterized in that the upper plates (P2, P3, P4) are not in a circular form. Système (1) selon l'une des revendications précédentes, caractérisé en ce que le ou les plateaux supérieurs (P2, P3, P4) ont une forme elliptique.System (1) according to one of the preceding claims, characterized in that the upper plate (s) (P2, P3, P4) have an elliptical shape. Système (1) selon l'une quelconque des revendications précédentes, caractérisé en ce que les plateaux supérieurs (P2, P3, P4) ne tournent pas à la même vitesse.System (1) according to any one of the preceding claims, characterized in that the upper plates (P2, P3, P4) do not rotate at the same speed. Système (1) selon l'une des revendications précédentes, caractérisé en ce que les plateaux (P1, P2, P3, P4) sont ajourés.System (1) according to one of the preceding claims, characterized in that the plates (P1, P2, P3, P4) are perforated. Système (1) selon l'une des revendications précédentes, caractérisé en ce que les plateaux (P1, P2, P3, P4) présentent des fentes (F1, F2) et/ou des ouvertures (O).System (1) according to one of the preceding claims, characterized in that the plates (P1, P2, P3, P4) have slots (F1, F2) and / or openings (O). Système (1) selon l'une des revendications précédentes, caractérisé en ce qu'une entrée circulaire (3) de combustible est aménagée au centre de l'empilement des plateaux (P1, P2, P3, P4), le centre de ladite entrée circulaire étant positionné sensiblement sur l'axe (A) et en ce qu'un tube (8) relié à cette entrée (3) permet l'admission du combustible, verticalement, au travers des plateaux (P1, P2, P3, P4) superposés.System (1) according to one of the preceding claims, characterized in that a circular fuel inlet (3) is arranged at the center of the stack of trays (P1, P2, P3, P4), the center of said inlet circular being positioned substantially on the axis (A) and in that a tube (8) connected to this inlet (3) allows the admission of the fuel, vertically, through the plates (P1, P2, P3, P4) superimposed. Système (1) selon l'une des revendications précédentes, caractérisé en ce qu'il comporte deux entrées d'air primaire (5, 6) de deux circuits d'air indépendants (C1, C2), un circuit d'air principal (C2) et un circuit d'air de refroidissement (C1).System (1) according to one of the preceding claims, characterized in that it comprises two primary air inlets (5, 6) of two independent air circuits (C1, C2), a main air circuit ( C2) and a cooling air circuit (C1). Système (1) selon l'une des revendications précédentes, caractérisé en ce qu'il comporte une couronne d'air (CA) d'injection autour du plateau inférieur (P1), ladite couronne d'air injectant de l'air radialement sur le plateau inférieur, pour éliminer la présence d'imbrûlés dans les cendres par combustion.System (1) according to one of the preceding claims, characterized in that it comprises a ring of injection air (CA) around the lower plate (P1), said ring of air injecting air radially on the lower plate, to eliminate the presence of unburnt material in the ashes by combustion. Système (1) selon l'une des revendications précédentes, caractérisé en ce que des tubes cylindriques coaxiaux (T1, T2, T3, T4) sont fixés aux plateaux (P1, P2, P3, P4), un tube cylindrique étant fixé à chaque plateau, et en ce que les plateaux sont entraînés en rotation au moyen de ces tubes, qui sont eux-mêmes entrainés en rotation de manière indépendante par des moyens d'entraînement.System (1) according to one of the preceding claims, characterized in that cylindrical tubes coaxial (T1, T2, T3, T4) are fixed to the plates (P1, P2, P3, P4), a cylindrical tube being fixed to each plate, and in that the plates are driven in rotation by means of these tubes, which are themselves rotated independently by drive means. Installation de combustion ou de gazéification alimentée en combustible solide comprenant un système de grille (1) selon l'une des revendications précédentes.Combustion or gasification installation supplied with solid fuel comprising a grate system (1) according to one of the preceding claims. Installation selon la revendication 14, caractérisée en ce que la composition du combustible est variable.Installation according to Claim 14, characterized in that the composition of the fuel is variable.
EP21163539.6A 2020-03-25 2021-03-18 Rotary de-ashing grate system for furnace of a combustion or gasification installation Active EP3885651B1 (en)

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FR2002937A FR3108709B1 (en) 2020-03-25 2020-03-25 Ash grate system for the hearth of a combustion or gasification installation

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Citations (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
FR870351A (en) * 1940-11-07 1942-03-10 Fireplace grate allowing the use as fuel: coal dust, all household waste, green or dry sawdust, all wood waste
CH226199A (en) * 1941-03-06 1943-03-31 Forni Ed Impianti Ind Ingg De Bartolomeis Spa Rotating grid.
EP3338024A1 (en) * 2015-08-18 2018-06-27 Gaggero, Paolo Stepped rotating grate for solid fuel burners or gasifiers

Patent Citations (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
FR870351A (en) * 1940-11-07 1942-03-10 Fireplace grate allowing the use as fuel: coal dust, all household waste, green or dry sawdust, all wood waste
CH226199A (en) * 1941-03-06 1943-03-31 Forni Ed Impianti Ind Ingg De Bartolomeis Spa Rotating grid.
EP3338024A1 (en) * 2015-08-18 2018-06-27 Gaggero, Paolo Stepped rotating grate for solid fuel burners or gasifiers

Also Published As

Publication number Publication date
EP3885651B1 (en) 2023-11-08
FR3108709A1 (en) 2021-10-01
EP3885651C0 (en) 2023-11-08
ES2965055T3 (en) 2024-04-10
FR3108709B1 (en) 2022-03-11
MA55152A (en) 2022-05-11

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