EP0176293B1 - Appareil de combustion à lit fluidisé avec recirculation-procédé et dispositif - Google Patents

Appareil de combustion à lit fluidisé avec recirculation-procédé et dispositif Download PDF

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Publication number
EP0176293B1
EP0176293B1 EP85306529A EP85306529A EP0176293B1 EP 0176293 B1 EP0176293 B1 EP 0176293B1 EP 85306529 A EP85306529 A EP 85306529A EP 85306529 A EP85306529 A EP 85306529A EP 0176293 B1 EP0176293 B1 EP 0176293B1
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Prior art keywords
bed
fuel
recycle
cyclone
combustor
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EP85306529A
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German (de)
English (en)
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EP0176293A3 (en
EP0176293A2 (fr
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Gary O. Goldbach
Jerry L. Cooper
John Louis Guillory
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Combustion Power Co Inc
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Combustion Power Co Inc
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    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F22—STEAM GENERATION
    • F22B—METHODS OF STEAM GENERATION; STEAM BOILERS
    • F22B31/00—Modifications of boiler construction, or of tube systems, dependent on installation of combustion apparatus; Arrangements of dispositions of combustion apparatus
    • F22B31/0007—Modifications of boiler construction, or of tube systems, dependent on installation of combustion apparatus; Arrangements of dispositions of combustion apparatus with combustion in a fluidized bed
    • F22B31/0084—Modifications of boiler construction, or of tube systems, dependent on installation of combustion apparatus; Arrangements of dispositions of combustion apparatus with combustion in a fluidized bed with recirculation of separated solids or with cooling of the bed particles outside the combustion bed
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F23—COMBUSTION APPARATUS; COMBUSTION PROCESSES
    • F23C—METHODS OR APPARATUS FOR COMBUSTION USING FLUID FUEL OR SOLID FUEL SUSPENDED IN  A CARRIER GAS OR AIR 
    • F23C10/00—Fluidised bed combustion apparatus
    • F23C10/02—Fluidised bed combustion apparatus with means specially adapted for achieving or promoting a circulating movement of particles within the bed or for a recirculation of particles entrained from the bed
    • F23C10/04—Fluidised bed combustion apparatus with means specially adapted for achieving or promoting a circulating movement of particles within the bed or for a recirculation of particles entrained from the bed the particles being circulated to a section, e.g. a heat-exchange section or a return duct, at least partially shielded from the combustion zone, before being reintroduced into the combustion zone
    • F23C10/08—Fluidised bed combustion apparatus with means specially adapted for achieving or promoting a circulating movement of particles within the bed or for a recirculation of particles entrained from the bed the particles being circulated to a section, e.g. a heat-exchange section or a return duct, at least partially shielded from the combustion zone, before being reintroduced into the combustion zone characterised by the arrangement of separation apparatus, e.g. cyclones, for separating particles from the flue gases
    • F23C10/10—Fluidised bed combustion apparatus with means specially adapted for achieving or promoting a circulating movement of particles within the bed or for a recirculation of particles entrained from the bed the particles being circulated to a section, e.g. a heat-exchange section or a return duct, at least partially shielded from the combustion zone, before being reintroduced into the combustion zone characterised by the arrangement of separation apparatus, e.g. cyclones, for separating particles from the flue gases the separation apparatus being located outside the combustion chamber
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F23—COMBUSTION APPARATUS; COMBUSTION PROCESSES
    • F23J—REMOVAL OR TREATMENT OF COMBUSTION PRODUCTS OR COMBUSTION RESIDUES; FLUES 
    • F23J15/00—Arrangements of devices for treating smoke or fumes
    • F23J15/02—Arrangements of devices for treating smoke or fumes of purifiers, e.g. for removing noxious material

Definitions

  • Fluid bed boilers burning high sulphur coal are well known in the art. These boilers use classical bubbling bed technology whereby the fluid bed operates with superficial velocities in the range of 4 to 12 ft/sec (1.2 - 3.7 m/s) and the bed is composed of particles with an average diameter of approximately 1000 microns. Coal is burned in the bubbling bed and limestone or dolomite sorbent is added to suppress the sulphur oxide emissions. The sorbent is added in particle sizes of 1000 to 3000 microns and the bed is composed largely of coal ash, spent sorbent, partially spent sorbent and partially burned fuel particles. The bubbling bed contains tubes within it to transfer heat to the steam.
  • Tubes are also mounted above the bed in the freeboard to transfer heat from the hot combustion gases, thus cooling them.
  • the bed elutriates fine particulates comprised of char, ash and partially spent sorbent. Many of these particles are captured by a recycle cyclone located downstream of the convective heat exchanger and these particles are returned to the bed in order to burn the fuel particles and allow unused sorbent to absorb more sulphur oxides. Very fine particles escape the recycle cyclone and are trapped in a filter system.
  • the flow rate in the recycle loop is approximately equal to the total solids flow rate of the fuel and the sorbent fed into the combustor.
  • Reh et. al. in German Patent Number DE 3,023,480 describes a different approach to obtain good sorbent utilization in suppressing sulphur oxides from combustion gases.
  • Reh et. al. passes combustion gas through a fluidized bed of sorbent with particle size of 30 to 200 microns and a superficial velocity of 3 to 30 ft/second (0.9 - 9.1 m/s), producing an entrained bed with a particle density 0.1 to 10kg/m3.
  • the particulate material entrained by the high gas velocity is removed by a recycle cyclone and returned to the bed, which is between 1300°F (704°C) and 2000°F (1093°C) in temperature.
  • the amount of material recycled per hour is approximately five times the bed weight.
  • This approach achieves good sulphur oxide suppression by the use of fine particulate with large surface area and vigorous mixing. Reh however, does not teach combustion in the entrained bed or heat recovery with tubes from the entrained bed.
  • the particulate material is entrained with the gas flow in the reactor and separated from it by a recycle cyclone downstream of the reactor whereupon the particulate is reintroduced into the base of the reactor.
  • Particle size ranges from 30 to 250 microns and the particle density is 10 to 40 kg/m3 in the upper portion of the reactor.
  • Heat is not recovered from the particulate material or gases in the reactor or recycle loop. Tubes in the reactor would be subject to high erosion and would not be effective in transferring heat because of the low particle density compared to that of a bubbling bed (500 kg/m3). Heat is recovered by draining a portion of the bed from the base of the reactor and cooling it in a separate fluid bed heat exchanger optimized for that process.
  • High combustion efficiency is obtained by completely burning small diameter fuel particles in the high turbulent reactor and the hot recycle loop.
  • Good sorbent usage is also obtained by using fine particulate material and maintaining it at an effective temperature throughout the reactor and recycle loop.
  • Limited nitrogen oxide control is obtained by progressively introducing combustion air along the length of the reactor.
  • the disadvantage of the system is the need for the separate fluidized bed heat exchanger and large recycle cyclones.
  • EP-A-112237 describes a fluidised bed combustion apparatus in which solids are collected from the fluidized bed combustor and then held in a separate vessel. These solids are stored in order to recover energy due to their high heating value. When the storage vessel is filled, the primary fuel to the combustor is shut off and the combustor is fired by injecting the collected material. This system therefore employs periodic re-injection rather than continuous recycle.
  • EP-A-118931 describes a dilute fluidised bed, that is to say, a bed in which there is no clear upper limit, thus, the entire reactor space is filled with the fluidised material and there is no freeboard.
  • the system appears to be isothermal as far as the cyclone and reactor are concerned though cooling is contemplated by the withdrawal of solids from the system for cooling before reintroduction. It would appear that reaction proceeds throughout the cycle.
  • a method of burning a solid fuel or a dirty liquid fuel in an atmospheric fluid bed combustor in order to recover useful energy comprises: maintaining a fluidized bed (B) of inert particles, ash, and partially burned fuel particles by passing a gas upwards through the bed; capturing substantially all elutriated fine material in the exhaust gas from the bed in a recycle cyclone and returning it to the bed; and recovering heat from the exhaust gas downstream of the recycle cylone; causing substantially all of the combustion of fuel to take place within the fluidised bed (B) and not from the free-board nor from the cycle; maintaining the recycle path of particles, including the fluidised bed, the free-board and the cyclone, at a substantially constant temperature; and operating the bed at a superificial velocity which causes significant but controlled elutriation of fines from the bed; characterised in that the average particle size is in the range of 100 to 800 microns; the bed is operated at a superficial velocity of 0.5 to 7 ft/second
  • the method includes the addition of a sulphur oxide sorbent into the atmospheric fluid bed combustor in order to suppress sulphur oxide emissions.
  • the method may also include the introduction of ammonia into the hot combustion gas stream immediately upstream of the recycle cyclone, in order to suppress nitrogen oxide emission.
  • the fluid bed combustor is operated at 1400-1500°F (760-816°C) to encourage minimum nitrogen oxide formation from combustion of the fuel, and to encourage char production with the attendant suppression of nitrogen oxide by hot char in the bed and in the recycle loop.
  • fluid bed combustion apparatus for performing the above method, comprising in combination: an atmospheric fluid bed combustor; means for feeding solid or dirty liquid fuel and inert particles into the combustor; means for introducing fluidizing air in the bottom of the combustor; a recycle cylone for capturing substantially all elutriated material escaping in the exhaust from the fluid bed combustor and returning the captured material to the fluid bed; means for recovering heat from the bed and from the exhaust gas stream but not in the free-board nor in the cyclone; and means for collecting dust from the cooled exhaust gas stream; characterised in that the cyclone is arranged to recycle the fines continuously.
  • the means for recovering the heat from the exhaust gas stream is located downstream of the means for capturing and returning the elutriated material.
  • the present invention utilizes a bubbling fluid bed combustor with tubes in the bed for heat transfer but with bed particles whose average diameter is in the range of 100 to 800 microns wherein 20% to 40% of the particles, respectively, are less than 200 microns in diameter.
  • the superficial velocity of the bed is preferably 3 to 7 ft/second (0.91 to 2.13 m/s), well below the 15 to 45 ft/second (4.6 to 13.7 m/s) of the entrained bed.
  • the result of the relatively low superficial velocity combined with a bed of small diameter particulate material is to produce a bubbling bed but with a high rate of elutriation of the fines component of the bed.
  • a particle density loading of 0.5 kg/m3 is achieved at the top of the bed. This compares to the 10-40 kg/m3 typical of an entrained bed.
  • the present invention uses particulate sizes typical of entrained beds but as much lower superficial velocity and hence produces a bubbling bed with substantially reduced transport of bed material.
  • the recycle rate of a conventional bubbling fluid bed boiler is approximately equal to the combined solids feed rates whereas the recycle rate of the present invention is preferably 20 times that value, equivalent to changing the bed every 40 minutes.
  • the present invention has no heat transfer surfaces between the bed and the recycle cyclone to cool the gas and the particulate material and hence contains an isothermal recycle loop operating at the ideal temperature for combustion or sulphur sorption.
  • the present invention uses ammonia injection at the inlet of the recycle cyclone for control of nitrogen oxide emissions.
  • the present invention has demonstrated an 86% reduction in nitrogen oxides (without the use of ammonia) by operating at a low combustion temperature of 1450°F (788°C) which reduces the evolution of nitrogen oxides from fuel bound nitrogen.
  • 1450°F (788°C) will reduce nitrogen oxides in the presence of oxygen.
  • 1450°F (788°C) large quantities of char are elutriated from the bed and circulate in the recycle loop. A portion of the ion of the 86% nitrogen oxides is contributed by its reaction with hot char but the degree of contribution is unkown.
  • the fluid bed combustion method and apparatus of the present invention may result in superior performance and efficiency.
  • the system comprises a fluid bed containing a fluid particle bed B supported on a distribution plate 12.
  • the combustor 10 includes cooling tubes 13 in the fluid bed B as well as a fuel feed 14, sorbent feed 15 and bed drain 16. Fluidizing air is introduced in the bottom of the combustor 10 at 17.
  • the hot gas and elutriated particulate material leaving the surface of the bed B pass through the freeboard 18 and are directed via a conduit 19 to a recycle cyclone 21 mounted above the bed to provide a straight dip leg 22 with adequate head in the dip leg 22 to provide a free flowing return of fine particulate to the bed.
  • the cut point of the recycle cyclone 21 is approximately 12 microns.
  • Ammonia is injected into the hot gas stream in the conduit 19 immediately upstream of the recycle cyclone by an ammonia injector 23 to suppress nitrogen oxides when burning fuel with fuel-bound nitrogen. Ammonia is supplied from a supply tank 24.
  • Hot gas leaving the recycle cyclone 21 via a conduit 25 passes through a convection heater 26 where the remaining heat is removed from the hot gas. Downstream of the convection heater 26 the gas passes through a filter system 27, such as a baghouse filter, to remove dust before being exhausted to the atmosphere through the stack 28.
  • a filter system 27 such as a baghouse filter
  • the fluid bed comprises a bubbling fluid bed combustor with a superficial velocity in the range of 0.5 ft/second to 7 ft/second (0.15 to 2.13 m/s) but with bed material in the size range of 45 microns to 2000 microns in diameter whereby 40% to 20% of the bed material, respectively, is less than 200 microns is diameter.
  • the large fraction is associated with dolomite feedstock size when dolomite is used.
  • the bubbling bed contains tubes to transfer heat from the hot fluid bed; the heat transfer coefficient on the outside of those tubes is in the range of 100 to 200 BTU/FT2/HR/F (567.8 - 1135.7 W/m2 K) because of the fine particulate material in the bed.
  • An additional solid fuel or liquid fuel may be fed directly into the bed with the fuel feed. If a sulphur sorbent such as limestone or dolomite is used, it is fed directly into the bed as well.
  • the fluid bed combustor 10 has a hot freeboard 18 with no heat transfer surfaces. A large number of fines are elutriated from the fluid bed B into the hot freeboard 18 in which excellent mixing conditions exist between the particles and the gas, and adequate residence time is available for chemical reactions. Most of the particulate material elutriated from the bed B into the freeboard 18 falls back into the bed but a significant amount is transported by the gas flow into the recycle cyclone 21 where it is separated from the gas and returned to the bed, all at substantially the same temperature as that of the fluid bed. Particle loading of the gas entering the cyclone 21 is approximately 0.5 kg/m3.
  • the extended residence time and the excellent mixing between the fine particulate char and the oxygen rich combustion gas in both the freeboard 18 and the recycle cyclone 21 cause the char particles to burn to completion before they can leave the recycle cyclone.
  • a benefit of the recycle char is believed to be the enhancement of highly efficient nitrogen oxide suppression at temperatures down to 1400°F (760°C).
  • the extended residence time and the excellent mixing between the fine sorbent particles and the sulphur oxides in the combustion gas in the hot freeboard 18 and the recycle cyclone 21 promote good sulphur oxide capture by the sorbent.
  • the fine particulate material spends approximately 1 second in the bed and 3 seconds in the freeboard and recycle cyclone.
  • the recycle cyclone is designed with a cut point of 5 microns and with a highly efficient dip leg to recycle easily most of the particles substantially larger than 5 microns, preventing their escape to the filter system 27.
  • the flow rate of the captured particulate material around the recycle loop 19 is approximately twenty times the combined flow rate of fuel and sorbent into the fluid bed.
  • the amount of material recycled per hour is twice the weight of the fluid bed itself.
  • ammonia is sprayed into the hot combustion gas stream immediately upstream 23 of the inlet to the recycle cyclone 21.
  • ammonia selectively and most efficiently reduces nitrogen oxides without a catalyst in the range of 1743°F to 1832°F (950 - 1000°C)
  • efficient reduction is normally achieved in the present invention by operating the fluid bed at 1450°F - 1650°F (788 - 900°C) and achieving 0 to 150°F (0 to 83K) of after burning above the bed B.
  • Injection of ammonia in ammonia/nitrogen oxide molar ratios of 1.5 to 2 provides nitrogen oxide suppression of 80% to 95% because of the excellent mixing occuring in the recycle cyclone 21.
  • the hot combustion gas and dust escaping the recycle cyclone 21 pass through the convective heat exchanger 26 where the gases are cooled to their exit temperature. Finally, the filter system 27 removes the dust before discharging the combustion gas to the atmosphere.
  • the present invention thus provides the capability to burn cleanly a wide variety of solid and liquid fuels, some of which may be very difficult to burn (such petroleum coke with 90% fixed carbon, i.e., low volatiles) or fuels which may contain sulphur or nitrogen or the combination of sulphur and nitrogen, all of which cause air pollution.
  • the present invention burns these fuels by using a conventional bubbling bed with a fine particulate composition and by recycling a large portion of those fines through a hot recycle loop above the bubbling bed.
  • a combustion efficiency of 99.4% can be obtained with petroleum coke with 90% fixed carbon, and 98% suppression of sulphur oxides can be achieved with a calcium sulphur molar ratio of 1.8.
  • a 95% suppression of nitrogen oxides can be obtained with an ammonia/nitrogen oxide molar ratio of 2. All this occurs within the framework of the fluid bed recycle system and occurs simultaneously.
  • a further benefit of the present invention is a large fluidization range of up to 15:1. Because the bubbling fluid bed is composed of fine particulate material, its minimum fluidization velocity may be as low as 0.5 ft/second (1.5 m/s). The invention will now be further illustrated in the following non-limiting Example.
  • Petroleum coke was burned with air in a fluidized bed combustor with a configuration as described in Figure 1.
  • the fluid bed combustor was 3ft (0.9m) in diameter and 12ft (3.7m) tall with the recycle cyclone mounted above it.
  • the combustor was refractory lined.
  • the bubbling bed was operated 3-1/2 to 4ft (1.1 to 1.2m) deep and contained air tubes to transfer heat out of the bed.
  • the petroleum coke used in the test had the following composition and heating value:
  • This fuel is difficult to burn because of the high fixed carbon with few volatiles. It also contains the elements of nitrogen and sulphur which produce nitrogen oxides and sulphur oxides as air pollutants.
  • the fuel was introduced to the fluid bed through a fuel feed, the majority of the fuel being between 50 and 400 microns in diameter.
  • Dolomite a sulphur sorbent, was introduced into the bed through the sorbent feed. Its composition was:
  • the fluid bed was initially composed of crushed dolomite with an average size of 800 microns.
  • the bed was comprised of ash, spent sorbent and partially spent sorbent; average particle size had stabilized at approximately 300 microns.
  • the fluid bed operated at an average superficial velocity of 4 ft/second (1.2 m/s). It was necessary to drain the bed periodically to maintain a constant level.
  • the recycle cyclone was designed to hold the majority of particles greater than 5 microns within the fluid bed combustor and was designed with a free flowing dip leg to provide little resistance in the particulate return path. As a result, high recycle flow rates of fines were achieved whereby the recirculation per hour was approximately twice the weight of the bed and twenty times the combined solids feed rate.
  • the fuel and sorbent particulate materials unable to leave the fluid bed with the gas stream until they had reached a very small size, were contained in the bed and comminuted by the action of the bed. Fuel particles, restrained from leaving the fluid bed combustor, burned to completion providing high combustion efficiency even with this difficult fuel containing approximately 90% fixed carbon. Combustion efficiency was further enhanced by the isothermal nature of the recycle path.
  • the fuel particles were heated to full combustion temperature in the bed and cooled neither in the freeboard nor in the recycle cyclone. Operating at a bed temperature of 1600°F (861°C) with 20% to 30% excess air, combustion efficiencies of 99.4% were achieved. Afterburning above the bed was in the range of 50°F to 100°F (28 to 56K).
  • ammonia was injected upstream of the cyclone to mix with the combustion gas and to reduce selectively nitrogen oxide to nitrogen and water according to the well-known reactions.
  • an NH3-to-NO molar ratio of 2 approximately 95% of the NO was suppressed.
  • the Utah coal had substantially less fixed carbon and substantially greater volatiles and hence was easier to burn than petroleum coke.
  • the size of the coal was minus 1 5/8 inches ( ⁇ 41.3mm).
  • the sulphur sorbent was the sample dolomite as used in Example I. Its composition was as follows:
  • Combustion efficiency with coal was 99.8% with 20% excess air at a bed temperature of 1600°F (871°C).
  • the combustor could be operated as cool as 1400°F (760°C) with only 20% excess air and yet maintain good combustion characteristics.
  • acceptable combustion characteristics could only be maintained at 1450°F (788°C) by increasing the excess air to 60%.

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  • Engineering & Computer Science (AREA)
  • Chemical & Material Sciences (AREA)
  • Combustion & Propulsion (AREA)
  • Mechanical Engineering (AREA)
  • General Engineering & Computer Science (AREA)
  • Physics & Mathematics (AREA)
  • Thermal Sciences (AREA)
  • Fluidized-Bed Combustion And Resonant Combustion (AREA)
  • Treating Waste Gases (AREA)

Claims (10)

  1. Procédé de combustion d'un combustible solide, ou d'un combustible liquide contenant des éléments polluants, dans un appareil de combustion atmosphérique à lit fluidisé (10) en vue de récupérer l'énergie utilisable, ce procédé consistant à maintenir un lit fluidisé (B) de particules inertes, de cendres et de particules de combustible partiellement brûlées, en faisant passer un gaz vers le haut à travers ce lit, à capturer, dans un cyclone de recyclage (21), pratiquement toute la matière, formée de fines séparées par élutriation, présente dans les gaz brûlés provenant du lit et à la renvoyer à ce lit, à récupérer la chaleur provenant des gaz brûlés se trouvant en aval de ce cyclone de recyclage (21), à faire en sorte que pratiquement toute la combustion du combustible ait lieu à l'intérieur du lit fluidisé et ni dans l'espace libre (18) situé au-dessus de ce lit fluidisé, ni dans le cyclone de recyclage (21), à récupérer l'énergie thermique provenant de la combustion à partir du lit fluidisé (B) et ni à partir du volume libre (18), ni à partir du cyclone (21), à maintenir à une température pratiquement constante le trajet de recyclage des particules, comprenant le lit fluidisé (B), le volume libre (18) et le cyclone (21), et à faire fonctionner le lit à une vitesse superficielle qui provoque une élutriation notable, mais contrôlée des fines à partir du lit, caractérisé en ce que la taille moyenne des particules est comprise entre 100 et 800 micromètres et en ce qu'on fait fonctionner le lit à une vitesse superficielle de 0,5 à 7 pieds/ seconde (0,15 à 2,2 m/s), ce qui provoque l'élutriation notable, mais contrôlée des fines à partir du lit, le recyclage des fines provenant du lit fluidisé étant continu et le débit de retour dans le cyclone de recyclage (21) en une heure étant équivalent à 1 à 5 fois le poids de la matière présente dans le lit.
  2. Procédé suivant la revendication 1, caractérisé en ce qu'on limite la postcombustion des particules de combustible au-dessus du lit fluidisé à une température ne dépassant pas 100°F (56°K) environ et ne dépassant pas de préférence 20°F (11°K) environ.
  3. Procédé suivant la revendication 1, caractérisé en ce qu'on maintient la température régnant dans le lit fluidisé (B) à une valeur comprise entre environ 1450°F (788°C) et 1650°F (900°C) et en ce qu'on limite la postcombustion des particules de combustible au-dessus du lit fluidisé à 150°F (83°K) environ, afin de supprimer les oxydes d'azote d'un combustible contenant de l'azote fixé sur lui, en présence d'ammoniac et sans qu'il soit besoin d'un catalyseur.
  4. Procédé suivant l'une quelconque des revendications précédentes, caractérisé en ce qu'on fait fonctionner l'appareil de combustion à lit fluidisé à 1400 à 1500°F (760 à 816°C) afin de favoriser une formation minimale d'oxydes d'azote à partir de la combustion du combustible et de favoriser une production de noir de carbone qui s'accompagne de la suppression des oxydes d'azote, dans le lit et dans la boucle de recyclage, à l'aide du noir de carbone à température élevée.
  5. Procédé suivant l'une quelconque des revendications précédentes, caractérisé par l'introduction d'un agent d'adsorption d'oxyde de soufre (15) dans l'appareil de combustion atmosphérique à lit fluidisé en vue de supprimer les émissions d'oxyde de soufre.
  6. Procédé suivant l'une quelconque des revendications précédentes, caractérisé par l'introduction d'ammoniac dans le courant de gaz de combustion, à température élevée, directement en amont (23) du cyclone de recyclage, en vue de supprimer les émissions d'oxyde d'azote.
  7. Installation de combustion à lit fluidisé permettant de mettre en oeuvre un procédé suivant l'une quelconque des revendications précédentes, comprenant, en combinaison, un appareil de combustion atmosphérique à lit fluidisé (10), des moyens permettant d'alimenter cet appareil de combustion en combustible solide, ou combustible liquide contenant des éléments polluants, et en particules inertes, des moyens (17) permettant d'introduire de l'air de fluidisation au fond de l'appareil de combustion (10), un cyclone de recyclage (21) permettant de capturer pratiquement toute la matière, séparée par élutriation, s'échappant dans les gaz brûlés provenant de l'appareil de combustion à lit fluidisé (10) et de renvoyer cette matière capturée au lit fluidisé (B), des moyens permettant de récupérer la chaleur provenant du lit (13) et provenant du courant de gaz brûlés (26), mais ni dans le volume libre (18), ni dans le cyclone, et des moyens permettant de recueillir les poussières (27) provenant du courant de gaz brûlés s'étant refroidis, caractérisée en ce que le cyclone est agencé de façon à recycler les fines d'une manière continue.
  8. Installation suivant la revendication 7, caractérisée par des moyens (15) permettant d'alimenter l'appareil de combustion atmosphérique à lit fluidisé (10) en agent d'adsorption d'oxyde de soufre, en même temps qu'en combustible.
  9. Installation suivant la revendication 7 ou la revendication 8, caractérisée par des moyens (23) permettant d'introduire de l'ammoniac dans le courant de gaz de combustion à température élevée, directement en amont du cyclone de recyclage (21).
  10. Installation suivant l'une quelconque des revendications 7 à 9, caractérisée en ce que les moyens (26) de récupération de chaleur à partir du courant de gaz brûlés sont disposés en aval des moyens (21) permettant de capturer et renvoyer la matière séparée par élutriation.
EP85306529A 1984-09-24 1985-09-13 Appareil de combustion à lit fluidisé avec recirculation-procédé et dispositif Expired - Lifetime EP0176293B1 (fr)

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US65430284A 1984-09-24 1984-09-24
US654302 1984-09-24

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EP0176293A2 EP0176293A2 (fr) 1986-04-02
EP0176293A3 EP0176293A3 (en) 1987-04-22
EP0176293B1 true EP0176293B1 (fr) 1991-04-03

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EP (1) EP0176293B1 (fr)
JP (1) JPH0799250B2 (fr)
CA (1) CA1271945A (fr)
DE (1) DE3582385D1 (fr)
DK (1) DK429885A (fr)
NO (1) NO853713L (fr)

Cited By (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US6260492B1 (en) 1996-04-12 2001-07-17 Abb Carbon Ab Method and apparatus for burning fuel in the free board of a pressurized fluidized bed with solids recirculation

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Also Published As

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JPS61105007A (ja) 1986-05-23
DK429885D0 (da) 1985-09-23
NO853713L (no) 1986-03-25
DK429885A (da) 1986-03-25
JPH0799250B2 (ja) 1995-10-25
DE3582385D1 (de) 1991-05-08
EP0176293A3 (en) 1987-04-22
CA1271945A (fr) 1990-07-24
EP0176293A2 (fr) 1986-04-02

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