EP0118455B1 - Bruleur de combustible solide pulverise - Google Patents

Bruleur de combustible solide pulverise Download PDF

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Publication number
EP0118455B1
EP0118455B1 EP83901967A EP83901967A EP0118455B1 EP 0118455 B1 EP0118455 B1 EP 0118455B1 EP 83901967 A EP83901967 A EP 83901967A EP 83901967 A EP83901967 A EP 83901967A EP 0118455 B1 EP0118455 B1 EP 0118455B1
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EP
European Patent Office
Prior art keywords
conduit
firing
air
housing
impeller
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.)
Expired
Application number
EP83901967A
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German (de)
English (en)
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EP0118455A4 (fr
EP0118455A1 (fr
Inventor
William H. Sayler
Justin Chad White
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T A S Inc
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T A S Inc
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Publication of EP0118455A4 publication Critical patent/EP0118455A4/fr
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    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B02—CRUSHING, PULVERISING, OR DISINTEGRATING; PREPARATORY TREATMENT OF GRAIN FOR MILLING
    • B02C—CRUSHING, PULVERISING, OR DISINTEGRATING IN GENERAL; MILLING GRAIN
    • B02C13/00—Disintegrating by mills having rotary beater elements ; Hammer mills
    • B02C13/14—Disintegrating by mills having rotary beater elements ; Hammer mills with vertical rotor shaft, e.g. combined with sifting devices
    • B02C13/18—Disintegrating by mills having rotary beater elements ; Hammer mills with vertical rotor shaft, e.g. combined with sifting devices with beaters rigidly connected to the rotor
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F23—COMBUSTION APPARATUS; COMBUSTION PROCESSES
    • F23D—BURNERS
    • F23D1/00—Burners for combustion of pulverulent fuel
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F23—COMBUSTION APPARATUS; COMBUSTION PROCESSES
    • F23K—FEEDING FUEL TO COMBUSTION APPARATUS
    • F23K1/00—Preparation of lump or pulverulent fuel in readiness for delivery to combustion apparatus
    • 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
    • F23K3/02—Pneumatic feeding arrangements, i.e. by air blast
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F23—COMBUSTION APPARATUS; COMBUSTION PROCESSES
    • F23K—FEEDING FUEL TO COMBUSTION APPARATUS
    • F23K2201/00—Pretreatment of solid fuel
    • F23K2201/10—Pulverizing

Definitions

  • the invention relates to a solid fuel pulverizing and burning system, including a staged impeller pulverizer for impacting relatively coarsely sized solid fuel and autogenously pulverizing it in turbulent air, said pulverizer having a housing with means for introducing solid fuel to be pulverized, means for introducing ambient primary air, staged impeller means, and discharge means for passing a stream of the primary air and autogenously pulverized solid fuel to a burner for firing into a combustion chamber of a furnace or other heating structure; the burner having means defining an ignition chamber, a firing conduit connected at one end to a conduit leading from the pulverizer and having a firing orifice defined at the downstream end and directed into said ignition chamber, an element within said firing conduit being formed with slanted vanes for imparting swirl to material flowing through said firing conduit; means for introducing a controlled quantity of swirling secondary air into said stream which consist of a secondary air conduit concentric with and surrounding said firing conduit and opening into said ignition chamber of the burner, wherein said firing conduit is
  • the system of the present invention is usable for burning pulverized fuels such as coal or other fossil fuels suspended in a stream of air in industrial furnaces, such as those used to heat gypsum-processing kettles, steam boilers, rotary kilns and metallurgical furnaces.
  • pulverized fuels such as coal or other fossil fuels suspended in a stream of air in industrial furnaces, such as those used to heat gypsum-processing kettles, steam boilers, rotary kilns and metallurgical furnaces.
  • the carrier air is often referred to as "primary” air and the main combustion air is referred to as "secondary” air.
  • secondary air Various problems arise in connection with the control of fuel flow rates and fuel/air ratios necessary to control the shape, size, and oxidizing or reducing characteristics of the flames needed for particular applications.
  • the achievable turndown ratio i.e. the ratio of maximum to minimum firing rate, is about 3 to 1. Attempted uses of commercially available equipment with greater turndown ratio result in unstable combustion or in flame-out.
  • the document GB-A-329 963 relates to a system of the kind initially described. Air discharged from a heater is divided into two portions, one of which is the primary air supply and the other the main air supply.
  • the primary air is pressurized by a fan and introduced into a pulverizing apparatus, in which fan plates secured to a vertically driven shaft are mounted within a casing having a fuel hopper at its upper end. Fuel discharge from the hopper to the inner portion of the upper fan member is thrown outwards against the casing wall and pulverized, then guided downwards by baffles to the lower fan members. From the lower part of the casing the mixture of air and pulverized fuel is distributed to fuel tubes of a furnace.
  • Each fuel tube penetrates a plate of a hollow front for a furnace and has a burner tube or sleeve slidably mounted thereon and passing slidingly into an ignition chamber through an opening in an inner partition or wall of the hollow front.
  • Angled vanes are located on a control boss, which is slidingly disposed within the burner sleeve and carried by a sliding rod extending axially through the fuel tube and operable from the outside.
  • Main air for combustion is supplied into the ignition chamber from a conduit which coaxially surrounds the front end of the burner sleeve and is spaced therefrom. The air enters through a ring of angled vanes producing a whirling movement and is supplied in radial direction towards the open end of the burner sleeve.
  • Control of the burning of the fuel/air mixture is made by adjusting the position of the exit end of the slidable burner sleeve relative to the furnace opening and the position of the angled vanes in the burner sleeve relative to the exit end of the fuel tube, as well as by varying the amount of the mixture of fuel and primary air and the amount of secondary air supplied to the ignition chamber.
  • This burner arrangement may be expected to provide a good combustible fuel/air mixture within the ignition chamber or furnace at some distance from the burner sleeve opening, nevertheless, the achievement of a flame of controlled shape near the burner orifice and easy initial ignition of the mixture at a point located at the input side of the combustion chamber appears difficult.
  • the document US-A-4221 174 describes a burner which utilizes a conical deflector rigidly mounted in a predetermined fixed position at the discharge end of and extending downstream from the firing conduit of the burner in order to diffuse a discharging stream of air and pulverized coal which is mixed with oxygen and an inert gas at varying ratios to provide optimum conditions for ignition of the discharged fuel mixture.
  • a burner for pulverized fuel furnaces which is arranged to discharge the incoming stream of fuel and air in the shape of a spirally whirling hollow cone is described in the document US-A-1 676 511.
  • Pulverized fuel is introduced into an air conduit from a second conduit having its discharge opening concentrically positioned with respect to the air conduit.
  • the mixture is passed into the furnace through a widening conical outer shell, within which an inner double-taper-ended inner cone is disposed.
  • An adjustment rod is slidably supported by spiders within the air conduit and is connected to the rear end of the inner cone.
  • the adjacent sides of the outer shell and the inner cone are substantially parallel, wherein the outer shell is provided with spiral vanes projecting inwardly toward the cone and the cone is provided with similar vanes projecting outwardly. Movement of the cone in axial direction increases or decreases the discharge area, wherein the overlapping spiral vanes coact to rotate the cone.
  • the cone evidently serves to assist the mixing of the pulverized fuel with the air and no provision is made for a supply of secondary air into the furnace. Because of the shaping requirements of the vanes of the conical outer shell and the inner cone, the range of adjustment of the cross- sectional area of the discharge opening is limited.
  • the document GB-A-795 887 describes a combustion device for burning powdered or liquid fuels, including a combustion chamber, a centrally arranged inlet pipe for supplying fuel and air to the combustion chamber, means disposed within the pipe for imparting a whirling motion to the fuel/air mixture flowing through the pipe, a pipe chamber surrounding the pipe and having an inlet for secondary air, an annular outlet from the secondary air chamber which is formed between the outlet opening of this chamber and a mouthpiece on the inlet pipe for the fuel/air mixture and opens directly into the combustion chamber, wherein at least a portion of the combustion chamber has an annular cross- section wider than the outlet opening of the secondary air chamber and a constricted outlet, so that a stationary eddy is formed in the annular portion of the combustion chamber from secondary air flowing back along the wall of the annular portion towards the annular outlet from the secondary air chamber.
  • the mouthpiece on the inlet pipe narrows toward the opening thereof and the mixture of fuel and air is ejected through the mouthpiece in the form of a conical jet into the combustion chamber.
  • the combustion device is provided with igniting means, an inspection opening, and an opening for additionally injecting combustible dust, liquid or gas into the annular portions. Possibilities of controlling the shape of the flame formed within the combustion chamber appear to be limited.
  • said secondary air conduit having an annular discharge orifice at its end, by said firing orifice being defined by an inturned circumferential lip sloping so as to direct the outflowing stream of carrier air and suspended solid fuel particles against a double-taper-ended valve element movably mounted downstream of said firing orifice for adjustment closer thereto or farther therefrom, and by mutually spaced spiders, that slidably support within the firing conduit an elongate operating rod having said valve element secured to one end thereof and extending backwardly through said firing conduit, defining said element having said slanted vanes.
  • the double-taper-ended valve element which is positioned movably at the discharge end of the firing conduit for the pulverized fuel and in line with the stream flow therethrough, creates turbulence and controls the quantity of the stream of air-suspended, pulverized, solid fuel fired into the ignition chamber of a furnace and the shape and character of the resulting flame.
  • the quantity and velocity of fuel passed to the burner is largely controlled by the amounts of air and solid fuel material fed to the pulverizer.
  • a pulverizer may be employed which exerts a drying action on the solid fuel as it is being pulverized inside the pulverizer by the inherent operating conditions therein.
  • Setting of the burner valve is determined for maximum operative effectiveness under actual operating conditions by observation of such operating conditions.
  • Substantially instantaneous ignition is achieved on the basis of an initial valve setting in conjunction with a fluid-fueled pilot ignitor, and rapid flame propagation is ensured by a heat retaining and reflecting ignition chamber of refractory material, which is cast to form as an integral block and through which flame-observation peep holes extend from the front of the burner. Observation of flame characteristics enable setting of the valve for optimum operation.
  • the pulverized coal may be consumed at the selected rates, and the plume of the flame may have a wide range of shapes and sizes and may have oxidizing or reducing characteristics and temperatures to meet the requirements of various industrial processing or space heating uses.
  • the invention Whilst eliminating or substantially alleviating disadvantages of present solid fuel pulverizing and burning systems, the invention provides for turndown ratios of fifteen to one or higher, in comparison with turndown ratios of three to one of presently available equipment.
  • the system of the invention is applied to the usual furnace portion 10, Figs. 1 and 3, of a conventional gypsum processing kettle 11, enabling such furnace to be fired with finely pulverized coal, about eighty percent of which is of forty 11m particle size and all of which will pass a standard two hundred mesh screen (screen opening: 74 pm).
  • Pulverized coal of this fineness is supplied on a continuous basis by a pulverizer 12 through a conduit 13 to a burner 14 attached to a forwardly protruding part 10a of the furnace 10 by means of a plate 14a which may or may not be provided as a part of burner 14.
  • a blower 15 supplies ambient secondary air to burner 14 through a conduit 16, primary air carrying the pulverized coal in suspension being supplied by pulverizer 12 through conduit 13.
  • Ambient primary air is supplied to pulverizer 12 through a conduit 17, Fig. 3, and run-of-the-mine coal (maximum size about two inches or 51 mm) is supplied through a conduit 18.
  • Tertiary air for helping to support combustion at and beyond the burner may be supplied through a series of openings 19, Figs. 2,3, and 4, provided in the front of the furnace circumferentially of the burner proper.
  • the pulverizer component of the present system is unique in a system of this kind in that, although machine impact is a factor, fineness of grind is achieved largely autogenously under drying conditions by particle-to-particle attrition.
  • other pulverizers of this general kind can be employed in this system so long as they perform in accordance with the teachings hereof.
  • vertical orientation is preferred to utilize the effect of gravity, other orientations are possible.
  • down-draft pulverizer 12 The details of down-draft pulverizer 12 are shown in Figs. 8-12.
  • a diametrically split, cylindrical housing 20, having bottom and top walls 21 and 22, respectively, is supported in vertical position by a stand 23.
  • the two semicircular sections of such housing are secured together by means of outwardly projecting flanges 20a and bolts 20b.
  • Journaled in the bottom and top walls by bearings 24 and 25 are opposite ends, respectively, of a rotatable impeller shaft 26 to which are affixed, in mutually spaced relationship, a series of impellers 27, 28, 29, 30 and 31 representing successive pulverizing stages from the upper inlet end of the housing to the lower discharge end thereof.
  • the impellers are preferably all imperforate, circular plates of uniform diameter, leaving respective, relatively narrow, annular spaces 32 between their circumferences and the inside cylindrical wall of the housing. They are mounted on shaft 26 by means of respective splined collars 33 and set screws (not shown).
  • a series of horizontal, annular partitions 34 extend inwardly between mutually adjacent impellers of respective sets of same from circumferential securement to the inside face of housing 20, to direct flow toward the impeller axis in opposition to centrifugal force exerted by the impellers.
  • the impellers are spaced from the respective partitions 34 to provide flow passages 35 therebetween as continuations of the annular spaces 32.
  • An electric motor 36 supported from housing 20 by bracket 37 drives impeller shaft 26 through a belt and pulley drive 38.
  • Uppermost impeller 27 has four radial bars 27a dividing the upper surface of its plate into quarter sections, as illustrated in Fig. 10. Bars 27a extend from the circumference of the plate inwardly toward, but short of, its collar 33 so as to leave an annular space 39 surrounding the collar.
  • This impeller is designed to receive, mix and distribute inflowing air and coal, as well as to shatter coal pieces by impact of the bars 27a thereagainst and by impact of the coal pieces against the housing wall and against each other as they are thrown outwardly by centrifugal force.
  • Inlet openings 40 and 41, Fig. 9, are provided through top wall 22 of housing 20 for connection with respective supply conduits 42 and 43, Fig. 3.
  • One is for the supply of ambient primary air, the other for the supply of run-of-the-mine coal or other solid fuel which may be utilized in any given instance. They are preferably provided at diametrically opposite sides of impeller shaft 26.
  • such opening is preferably elongate rectangular in shape, with the longitudinal sides concavely curved toward the impeller axis, as illustrated in Fig. 9. Since it is desirable that the primary air and fuel supplies be interchangeable, both of the openings and conduits leading thereinto are preferably identical. Where, as here, the opening 41 and supply conduit 43 are used to supply the solid fuel, deflector skirts 44 may be provided to reduce the size of the fuel inlet opening relative to that for the air.
  • Solid fuel is conveyed to its supply conduit through a tramp iron detector (not shown) to avoid damage to the pulverizer.
  • the spacings between the several impellers may be uniform, but in the illustrated instance are varied as shown in Fig. 8.
  • Second stage impeller 28 has six radial bars 28a, Fig. 11, instead of four, and impellers 29 and 30 of the third and fourth stages have four bars each, 29a and 30a, respectively, Fig. 8, the same as impeller 27 of the first stage.
  • the fifth, i.e. final, stage effects discharge of the pulverized solid fuel suspended in air through a tangential discharge conduit 45, Fig. 12, which is connected by conduit 13 to burner 14.
  • Impeller 31 of such fifth stage has four relatively thin and tall, air motivating vanes 31a placed radially on the upper surface of its imperforate plate similarly to but instead of the thicker and lower impact bars of the other impellers. Also, it has sets of diametrically opposite, mutually spaced, relatively slender bars 31b on its undersurface to stir up any tendency for solid particles to settle.
  • the height of vanes 31 a extends over much of the height of the discharge outlet so as to sweep the pulverized fuel and carrier air therethrough.
  • the inside cylindrical walls of housing 20 are preferably covered by a thick ceramic lining 46 to resist abrasion and consequent wear, as well as to aid in pulverization, and there are preferably provided mutually spaced, vertical, impact bars 47 secured to such inside cylindrical walls and projecting into the annular spaces 32 of stages second through fifth.
  • a downwardly-turned lip 34a is preferably provided as an addition to the uppermost annular partition 34.
  • the turbulent air and solid fuel particle mix is funneled from the first stage onto the second stage, where it comes under the influence of a greater number of activating bars than in the first stage and then follows a sinuous or serpentine course as it passes through the several succeeding stages.
  • the input energy to the pulverizer is normally sufficient to produce operating heat effective to dry even wet fuel fed thereinto along with ambient air.
  • energy input by motor 36 should provide an RPM for impeller shaft 26 that imposes an outer tip speed for the impeller bars and vanes of between 135 and 150 miles per hour, 146 miles per hour being optimum (217, 241 and 235 km/h, respectively).
  • Burner 14 as here illustrated, Figs. 4-7 comprises a firing nozzle which includes a firing conduit 48, connected at one end to conduit 13 leading from pulverizer 12 and having a firing orifice 49 at the downstream end.
  • firing orifice 49 is advantageously defined by an inturned lip 48a sloping downstream, so as to direct the outflowing stream of carrier air and suspended solid fuel particles against a valve element 50, which is preferably double-taper-ended, as at 50a and 50b, and positioned in-line with flow of material to impart maximum turbulence to the emerging stream.
  • the angles of the tapered ends of the valve element 50 may be varied for particular applications.
  • Valve element 50 is secured to one end of an operating rod 51, which extends backwardly through firing conduit 48 and outwardly thereof through a packing gland 51a in the wall of an elbow 52 in the conduit.
  • a handle 51 b on the exposed end of rod 51 provides for convenient manipulation in either pushing or pulling such rod to position valve element 50 either farther away from or closer to firing orifice 49 to change flame shape for particular purposes and to otherwise control operating characteristics.
  • a set screw 51c provides for locking valve element 50 in adjusted position.
  • Operating rod 51 is slidably supported by mutually spaced spiders 53 within firing conduit 48, which have vanes 53a angled to impart swirl to the stream of carrier air and suspended solid fuel particles.
  • Concentric with and surrounding firing conduit 48 is a secondary air conduit 54 extending in cantilever fashion from securement to burner plate 14a and having conduit 16 connected in flow communication therewith.
  • the downstream end, i.e. firing orifice 49, of conduit 48 and the downstream end 54a of conduit 54 open into an ignition chamber 55 of the burner, which is defined by heat retaining and reflecting refractory material 56, to provide a divergent inlet portion 55a in which valve element is positioned, and a discharge portion 55b of uniform diameter.
  • Such material is advantageously a commercial refractory produced in powder form under the proprietary name of "Krusite" by A. P. Green Refractories Co., and is mixed with water and cast into final form as an integral block.
  • Firing conduit 48 is slidable within and along secondary air conduit 54 to place firing orifice 49 at variable distances from, or right at, the downstream end of secondary air conduit 54.
  • a section of flexible pipe 57 in conduit 13 accommodates the movement of the firing conduit 48, and a set screw 58 provides for locking it in its adjusted position.
  • the flow velocity in firing conduit 48 is sufficient to suspend enough pulverized coal particles to render the primary mixture in such conduit too fuel-rich for effective combustion, or at least sufficiently rich in coal particle content relative to air content for a low flame propagation rate such as will prevent flashback.
  • the weight of air in the primary mixture may range from 10% to 30% of the mixture weight, but should be maintained constant for any particular application.
  • Introducing secondary air into the primary fuel feed mixture adjusts the coal/air ratio of such primary mixture for ignition and combustion.
  • the amount of secondary air supplied is controlled by a valve 16a, Fig. 4, in conduit 16 to produce oxidizing, reducing, or stoichiometric combustible mixtures as desired for the particular application and to at least partially control the shape of the flame plume in the furnace.
  • a vane 59 may be pivotally mounted at the entrance of secondary air from conduit 16 into conduit 54 for selective angular orientation, so that an adjustable swirling component of velocity is imparted to the secondary air as it enters conduit 54. This swirling component persists through ignition chamber 55 to help shape the flame plume. Making use of valve 16a, the operation may induce more pronounced swirls to aid the valved firing nozzle to produce correspondingly more full, but shorter plumes, and vice versa.
  • firing conduit 48 For start-up of the furnace, the position of firing conduit 48 is first adjusted relative to secondary air conduit 54 in accordance with firing conditions, and valve element 50 is positioned about three inches from firing orifice 49. Motor 36 of pulverizer 12 and blower 15 supplying secondary air to burner 14 are energized.
  • the flame from an igniter torch 60 is directed into the highly turbulent mixture of air and pulverized solid fuel in ignition chamber 55 by way of an ignition passage 61, which extends from the front of the burner 14 through plate 14a and the block of refractory material 56 and opens into the ignition chamber 55. Ignition should take place instantaneously.
  • valve element 50 is established by movement thereof from its initial position either toward or away from nozzle firing orifice 49.
  • firing conduit 48 Although it is not usually necessary to readjust the position of firing conduit 48 to relocate its firing orifice 49 relative to the annular discharge orifice of secondary air conduit 54 at its end 54a, that can be done if found expedient in order to establish optimum conditions for flame propagation in and beyond ignition chamber 55.
  • refractory block 56 becomes heated to a temperature of from about 2000 to 3000°F (1094 to 1650°C), and serves as a continuing source of ignition heat for the fuel feed to the burner 14.
  • valve element 50 is positioned, as previously indicated, by manipulation of rod 51 to adjust flow of the primary fuel mixture into the ignition chamber 55.
  • the supply of secondary air is then adjusted by means of valve 16a for the desired coal to air ratio.
  • the combustion energy provided by the system is controlled and maintained by input offuel and air.
  • the operator usually first adjusts the flame in this manner and then makes whatever further adjustments therein and to the setting of vane 59 and to valve 16a that may be required to modify flame swirl to achieve shape of flame plume suitable for the particular application. If necessary, he may analyze the furnace exhaust gases to determine the oxidizing or reducing character of the flame.
  • the capability of the burner 14 to accommodate large variations in coal consumption for achieving various desired results in the operation of a furnace or boiler is believed to come largely from thorough mixing of pulverized coal and air in both the pulverizer 12 and the firing nozzle of the burner 14 and by the reliability of continuing ignition.
  • Coal feed rates to the burner 14 can be successfully adjusted over a turndown range of 15:1, or higher, with stable combustion and without flameout or flashback.
  • the shape, temperature, and oxidizing or reducing potential of the flame plume may be varied widely and controlled closely.
  • the shorter, more expansive plume preferred for boiler heating is readily achieved with the lower coal firing rates, the flow of secondary air being adjusted for relatively rapid combustion.
  • the longer plume preferred in industrial process furnaces is achieved with higher coal firing rates.
  • the previously discussed adjustable swirling of injected secondary air provides further flame shape control at the selected mixture ratio and coal consumption rate.
  • the firing conduit 48 of the firing nozzle may be four inches (10.2 cm) in diameter, recirculation conduit 54 six inches (15.2 cm) in diameter, firing orifice 49 three and one-half inches (8.9 cm) in diameter, portion 55b of ignition chamber 55 fourteen inches (35.6 cm) in diameter, and the overall length of the ignition chamber twenty-four inches (61 cm).
  • the firing nozzle may incorporate manifolding to accommodate two or more burners 14 simultaneously utilizing a single pulverizer 12, or more than one firing nozzle may be served by a single pulverizer 12.
  • an ultraviolet scanner such as a Honeywell "Mini Peeper", No. C7027A-1023, is installed in each passage 62.

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  • Engineering & Computer Science (AREA)
  • Chemical & Material Sciences (AREA)
  • Combustion & Propulsion (AREA)
  • Mechanical Engineering (AREA)
  • General Engineering & Computer Science (AREA)
  • Food Science & Technology (AREA)
  • Solid Fuels And Fuel-Associated Substances (AREA)

Abstract

Un système de pulvérisation et de combustion de combustible solide, tel du charbon ou autres combustibles fossiles, se caractérisant par un rapport d'atténuation possible allant au moins jusqu'à 1 à 15, comprend un pulvérisateur unique (12) pouvant exécuter une pulvérisation aussi bien autogène que par impact, et un brûleur unique (14) comprenant un ajutage de mise à feu à soupape possédant une conduite de mise à feu (48) pourvue d'un orifice de mise à feu (49) et d'une alimentation réglable d'air secondaire (16, 16a, 54, 59). Un élément de vanne mobile (50), ayant de préférence la forme d'un corps à extrémité biconique, disposé en aval de l'orifice de mise à feu (49), fait passer un courant turbulent d'air primaire et secondaire mélangé, dans lequel sont suspendues des particules de combustible pulvérisé, dans une chambre d'allumage (55) et règle la forme de la flamme.

Claims (18)

1. Un système de pulvérisation et de brûlage de combustible solide, comportant
- un pulvérisateur de propulsion à étages (12) pour venir en contact avec le combustible solide de dimensions relativement importantes et pour le pulvériser de manière autogène dans un air turbulent, ledit pulvérisateur (12) comportant une enveloppe (20) munie de moyens pour introduire le combustible solide à pulvériser, des moyens pour introduire de l'air primaire ambient, des moyens de propulsion à étages, et des moyens de sortie pour faire passer un courant d'air primaire et de combustible solide pulvérisé de manière autogène vers un brûleur (14) pour l'allumage dans une chambre de combustion d'un four (10) ou d'une autre structure de chauffage,
- le brûleur (14) comportant des moyens définissant une chambre d'allumage (55), une conduite d'allumage (48) reliée à une extrémité à une conduite (13) venant du pulvérisateur (12) et présentant un orifice d'allumage (49) défini à l'extrémité aval et dirigé dans ladite chambre d'allumage (55), un élément présentant des aubes inclinées (53a) étant prévu dans ladite conduite d'allumage (48) pour donner un mouvement tourbillonnaire à la matière circulant dans ladite conduite d'allumage (48),
- des moyens pour introduire une quantité commandée d'air secondaire tourbillonnant dans ledit courant, ces moyens comportant une conduite (54) d'air secondaire concentrique à ladite conduite d'allumage (48), entourant celle-ci et débouchant dans ladite chambre d'allumage (55) du brûleur (14), ladite conduite d'allumage (48) pouvant coulisser longitudinalement par rapport à ladite conduite (54) d'air secondaire et à la chambre d'allumage (55) de manière à permettre un positionnement sélectif dudit orifice d'allumage (49) par rapport à celle-ci, des moyens étant prévus pour fixer ladite conduite d'allumage (48) dans la position sélectionnée,
- des moyens pour allumer l'air et le combustible solide pulvérisé turbulents dans ladite chambre d'allumage (55), et
- des moyens pour observer les conditions dans ladite chambre d'allumage (55),
caractérisé en ce que
- ladite conduite (54) d'air secondaire présente un orifice annulaire de sortie à son extrémité (54a),
- ledit orifice d'allumage (49) est défini par une lèvre circonférencielle (48a) tournée vers l'intérieur et inclinée de manière à diriger le courant sortant d'air porteur et des particules suspendues de combustible solide contre un élément de vanne (50) qui présente une extrémité (50a, 50b) à deux cônes et qui est monté de manière mobile en avail dudit orifice d'allumage (49) pour pouvoir être réglé par rapprochement ou par éloignement par rapport à celui-ci, et
- des armatures (53) mutuellement espacées qui supportent de manière coulissante, à l'intérieur de ladite conduite d'allumage (48), une tige allongée (51) d'actionnement portant fixement à l'une de ses extrémités ledit élément de vanne (50) et s'étendant vers l'arrière en traversant ladite conduite d'allumage (48), et qui définit ledit élément comportant lesdites aubes inclinées (53a) pour donner un mouvement tourbillonnaire à la matière circulant dans ladite conduite d'allumage (48).
2. Un système selon la revendication 1, caractérisé en ce que le pulvérisateur (12) comporte
- un arbre (26) qui est monté de manière tournante dans l'enveloppe (20),
- une série de propulseurs (27 à 31) fixés audit arbre (26) suivant un agencement d'espacement mutuel définissant les étages respectifs de pulvérisation et se terminant près de ladite enveloppe (20) pour définir autour de celle-ci un espace cir- conférenciel d'écoulement, lesdits propulseurs (27 à 31) étant munis d'éléments de propulsion de l'air et d'impact avec les particules solides,
- des moyens d'entrée d'air adjacents à une extrémité de ladite enveloppe (20) comme moyens pour introduire l'air primaire de manière à fournir un courant d'air porteur,
- des moyens d'entrée du combustible solide adjacents à ladite extrémité de l'enveloppe (20) comme moyens pour introduire le combustible solide à pulvériser,
- des moyens à conduite de sortie adjacents à l'autre extrémité de l'enveloppe (20) et reliées à la conduite d'allumage (48) comme moyens pour diriger le courant d'air porteur et le combustible solide pulvérisé vers le brûleur (14), et
- des moyens pour faire tourner l'arbre de propulsion (26).
3. Un système selon la revendication 2, caractérisé en ce que le pulvérisateur (12) comporte de plus une série de cloisons annulaires (34) fixées à l'enveloppe et s'étendant périphériquement par rapport à celle-ci et entre des propulseurs mutuellement adjacents des ensembles respectifs de propulseurs mutuellement adjacents (27 à 31) pour diriger l'écoulement vers l'axe de propulsion en opposition à la force centrifuge exercée par les propulseurs (27 à 31).
4. Un système selon la revendication 3, caractérisé en ce que les moyens d'entrée d'air et les moyens d'entrée de combustible sont agencés pour avoir une sortie directement sur le propulseur du premier étage (27) et en ce que le propulseur du second étage (28) présente un plus grand nombre d'éléments d'impact que le propulseur du premier étage (27).
5. Un système selon la revendication 4, caractérisé en ce que la cloison annulaire (34) entre les propulseurs du premier et du second étages (27 et 28, respectivement) présente de plus une lèvre de sortie (34a) tournée intérieurement vers l'axe des propulseurs (27 à 31) pour concentrer la matière dudit premier étage vers ledit second étage.
6. Un système selon la revendication 2, caractérisé en ce que la face intérieure de l'enveloppe (20) présente des barres d'impact (47) espacées à la périphérie de celle-ci et disposées à l'intérieur dudit espace d'écoulement.
7. Un système selon la. revendication 3, caractérisé en ce que l'enveloppe (20) est cylindrique et que, avec l'arbre de propulsion (26), elle est disposée verticalement, l'extrémité supérieure de l'enveloppe (20) étant fermée par une paroi supérieure, les propulseurs (27 à 31) et les cloisons annulaires (34) s'étendant horizontalement et les moyens d'entrée d'air primaire et les moyens d'entrée du combustible solide étant situés dans ladite cloison supérieure.
8. Un système selon la revendication 7, caractérisé en ce que les moyens d'entrée d'air primaire et les moyens d'entrée du combustible solide comportent respectivement des ouvertures allongées (40, 41) sensiblement rectangulaires traversant la paroi supérieure de l'enveloppe (20) sur les côtés diamétralement opposés de l'ace de propulsion, et des conduites d'écoulement (42, 43) menant aux ouvertures respectives.
9. Un système selon la revendication 8, caractérisé en ce que les grands côtés de l'ouverture rectangulaire allongée (40) d'entrée d'air sont sensiblement uniformément courbés de manière concave vers l'axe de propulsion.
10. Un système selon la revendication 9, caractérisé en ce que, d'une part, l'ouverture (40) d'entrée d'air et la conduite (42) et, d'autre part, l'ouverture (41) d'entrée de combustible et la conduite (43) sont formées de manière similaire pour pouvoir être utilisées de manière interchangeable, et en ce que des jupes déflectrices (44) sont prévues dans l'ouverture sélectionnée (41) d'entrée du combustible solide de manière à réduire sa taille par rapport à celle de ladite ouverture (40) d'entrée d'air.
11. Un système selon la revendication 7, caractérisé en ce que les moyens à conduite de sortie débouchent sensiblement tangentiellement dans l'étage de propulsion le plus bas à travers la paroi latérale cylindrique de l'enveloppe (20) et en ce que le propulseur (31) dudit étage présente des aubes (31a) fixées à sa surface supérieure, et faisant saillie par rapport à celle-ci, sensiblement à la hauteur de l'ouverture dans lesdits moyens à conduite de sortie de manière à agir comme un ventilateur d'éjection pour le courant d'air primaire porteur et le combustible pulvérisé entraîné dans celui-ci.
12. Un système selon la revendication 1, caractérisé ce ce que la structure et l'agencement du pulvérisateur (12) et les moyens pour actionner celui-ci sont tels que la fourniture d'énergie pendant le fonctionnement est suffisante pour provoquer une chaleur de séchage du combustible solide à l'intérieur de l'enveloppe (20) lors du fonctionnement avec une entrée d'air ambiant.
13. Un système selon la revendication 7, caractérisé en ce que la paroi cylindrique intérieure de l'enveloppe (20) est garnie de céramique.
14. Un système selon la revendication 11, caractérisé en ce que le propulseur (31) du dernier étage de propulsion comporte de plus des éléments sur sa face inférieure pour participer à l'éjection de toutes particules qui tendent à s'établir sur la paroi inférieure de l'enveloppe (20).
15. Un système selon la revendication 1, caractérisé en ce que les moyens pour observer les conditions à l'intérieur de la chambre d'allumage (55) du brûleur (14) comportent au moins un passage (62) d'observation visuelle qui traverse l'avant du brûleur (14) et débouche dans ladite chambre d'allumage (55).
16. Un système selon la revendication 1, caractérisé en ce que les moyens d'allumage du brûleur consistent en un passage (61) qui traverse l'avant du brûleur (14) et qui débouche dans la chambre d'allumage (55), ledit passage (61) étant agencé pour comporter un allumeur (60) qui le traverse et qui est dirigé vers ladite chambre d'allumage (55).
17. Un système selon la revendication 1, caractérisé en ce qu'il est prévu une entrée d'air tertiaire vers le four (10) de manière à entourer les moyens définissant la chambre d'allumage (55) avec un écoulement dudit air tertiaire.
18. Un système selon la revendication 1, caractérisé en ce que la chambre d'allumage (55) est constituée par un bloc d'une seule pièce d'une matière réfractaire (56) de retenue et de réflexion de la chaleur qui est moulé à la forme.
EP83901967A 1982-05-14 1983-04-11 Bruleur de combustible solide pulverise Expired EP0118455B1 (fr)

Applications Claiming Priority (2)

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US37834782A 1982-05-14 1982-05-14
US378347 1982-05-14

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EP0118455A1 EP0118455A1 (fr) 1984-09-19
EP0118455A4 EP0118455A4 (fr) 1985-07-30
EP0118455B1 true EP0118455B1 (fr) 1987-06-03

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EP (1) EP0118455B1 (fr)
KR (1) KR910006233B1 (fr)
AU (3) AU566176B2 (fr)
CA (1) CA1203435A (fr)
DE (1) DE3371938D1 (fr)
WO (1) WO1983004085A1 (fr)
ZA (1) ZA833054B (fr)

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US9039407B2 (en) 2006-11-17 2015-05-26 James K. McKnight Powdered fuel conversion systems and methods
EP2094970B1 (fr) 2006-11-17 2017-01-11 Summerhill Biomass Systems, Inc. Combustibles en poudre, leurs dispersions, et dispositifs de combustion y relatifs
CA2720970A1 (fr) 2008-04-07 2009-10-15 James K. Mcknight Systemes et procedes de conversion de combustible en poudre
WO2015069784A1 (fr) * 2013-11-08 2015-05-14 Zheng Shi Ajustement de la caractéristique de flamme à l'intérieur d'une chambre de combustion

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Also Published As

Publication number Publication date
AU7715387A (en) 1987-11-26
KR910006233B1 (ko) 1991-08-17
AU601470B2 (en) 1990-09-13
AU566176B2 (en) 1987-10-08
DE3371938D1 (en) 1987-07-09
EP0118455A4 (fr) 1985-07-30
EP0118455A1 (fr) 1984-09-19
AU601469B2 (en) 1990-09-13
ZA833054B (en) 1984-01-25
KR840004566A (ko) 1984-10-22
WO1983004085A1 (fr) 1983-11-24
CA1203435A (fr) 1986-04-22
AU1604983A (en) 1983-12-02
AU7715487A (en) 1987-11-26

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