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WO1992011499A1 - Procede et appareil de regulation de la temperature pour reacteur a lit fluidise en circulation - Google Patents

Procede et appareil de regulation de la temperature pour reacteur a lit fluidise en circulation Download PDF

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Publication number
WO1992011499A1
WO1992011499A1 PCT/FI1991/000384 FI9100384W WO9211499A1 WO 1992011499 A1 WO1992011499 A1 WO 1992011499A1 FI 9100384 W FI9100384 W FI 9100384W WO 9211499 A1 WO9211499 A1 WO 9211499A1
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WIPO (PCT)
Prior art keywords
fluidized bed
bed reactor
reactor
particles
recited
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.)
Ceased
Application number
PCT/FI1991/000384
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English (en)
Inventor
Olli Arpalahti
Matti Hiltunen
Kurt Westerlund
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Ahlstrom Corp
Original Assignee
Ahlstrom Corp
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Filing date
Publication date
Application filed by Ahlstrom Corp filed Critical Ahlstrom Corp
Priority to AU90439/91A priority Critical patent/AU652204B2/en
Publication of WO1992011499A1 publication Critical patent/WO1992011499A1/fr
Anticipated expiration legal-status Critical
Ceased legal-status Critical Current

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Classifications

    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
    • B01J—CHEMICAL OR PHYSICAL PROCESSES, e.g. CATALYSIS OR COLLOID CHEMISTRY; THEIR RELEVANT APPARATUS
    • B01J8/00—Chemical or physical processes in general, conducted in the presence of fluids and solid particles; Apparatus for such processes
    • B01J8/18—Chemical or physical processes in general, conducted in the presence of fluids and solid particles; Apparatus for such processes with fluidised particles
    • B01J8/1836—Heating and cooling the reactor
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
    • B01J—CHEMICAL OR PHYSICAL PROCESSES, e.g. CATALYSIS OR COLLOID CHEMISTRY; THEIR RELEVANT APPARATUS
    • B01J8/00—Chemical or physical processes in general, conducted in the presence of fluids and solid particles; Apparatus for such processes
    • B01J8/18—Chemical or physical processes in general, conducted in the presence of fluids and solid particles; Apparatus for such processes with fluidised particles
    • B01J8/24—Chemical or physical processes in general, conducted in the presence of fluids and solid particles; Apparatus for such processes with fluidised particles according to "fluidised-bed" technique
    • B01J8/26—Chemical or physical processes in general, conducted in the presence of fluids and solid particles; Apparatus for such processes with fluidised particles according to "fluidised-bed" technique with two or more fluidised beds, e.g. reactor and regeneration installations
    • B01J8/28—Chemical or physical processes in general, conducted in the presence of fluids and solid particles; Apparatus for such processes with fluidised particles according to "fluidised-bed" technique with two or more fluidised beds, e.g. reactor and regeneration installations the one above the other
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
    • B01J—CHEMICAL OR PHYSICAL PROCESSES, e.g. CATALYSIS OR COLLOID CHEMISTRY; THEIR RELEVANT APPARATUS
    • B01J8/00—Chemical or physical processes in general, conducted in the presence of fluids and solid particles; Apparatus for such processes
    • B01J8/18—Chemical or physical processes in general, conducted in the presence of fluids and solid particles; Apparatus for such processes with fluidised particles
    • B01J8/24—Chemical or physical processes in general, conducted in the presence of fluids and solid particles; Apparatus for such processes with fluidised particles according to "fluidised-bed" technique
    • B01J8/38—Chemical or physical processes in general, conducted in the presence of fluids and solid particles; Apparatus for such processes with fluidised particles according to "fluidised-bed" technique with fluidised bed containing a rotatable device or being subject to rotation or to a circulatory movement, i.e. leaving a vessel and subsequently re-entering it
    • B01J8/384—Chemical or physical processes in general, conducted in the presence of fluids and solid particles; Apparatus for such processes with fluidised particles according to "fluidised-bed" technique with fluidised bed containing a rotatable device or being subject to rotation or to a circulatory movement, i.e. leaving a vessel and subsequently re-entering it being subject to a circulatory movement only
    • B01J8/388—Chemical or physical processes in general, conducted in the presence of fluids and solid particles; Apparatus for such processes with fluidised particles according to "fluidised-bed" technique with fluidised bed containing a rotatable device or being subject to rotation or to a circulatory movement, i.e. leaving a vessel and subsequently re-entering it being subject to a circulatory movement only externally, i.e. the particles leaving the vessel and subsequently re-entering it
    • C—CHEMISTRY; METALLURGY
    • C21—METALLURGY OF IRON
    • C21B—MANUFACTURE OF IRON OR STEEL
    • C21B13/00—Making spongy iron or liquid steel, by direct processes
    • C21B13/0033—In fluidised bed furnaces or apparatus containing a dispersion of the material
    • C—CHEMISTRY; METALLURGY
    • C22—METALLURGY; FERROUS OR NON-FERROUS ALLOYS; TREATMENT OF ALLOYS OR NON-FERROUS METALS
    • C22B—PRODUCTION AND REFINING OF METALS; PRETREATMENT OF RAW MATERIALS
    • C22B5/00—General methods of reducing to metals
    • C22B5/02—Dry methods smelting of sulfides or formation of mattes
    • C22B5/12—Dry methods smelting of sulfides or formation of mattes by gases
    • C22B5/14—Dry methods smelting of sulfides or formation of mattes by gases fluidised material
    • 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 or dispositions of combustion apparatus
    • F22B31/0007—Modifications of boiler construction, or of tube systems, dependent on installation of combustion apparatus; Arrangements or 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 or 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
    • F27—FURNACES; KILNS; OVENS; RETORTS
    • F27B—FURNACES, KILNS, OVENS OR RETORTS IN GENERAL; OPEN SINTERING OR LIKE APPARATUS
    • F27B15/00—Fluidised-bed furnaces; Other furnaces using or treating finely-divided materials in dispersion
    • F27B15/02—Details, accessories or equipment specially adapted for furnaces of these types
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F27—FURNACES; KILNS; OVENS; RETORTS
    • F27B—FURNACES, KILNS, OVENS OR RETORTS IN GENERAL; OPEN SINTERING OR LIKE APPARATUS
    • F27B15/00—Fluidised-bed furnaces; Other furnaces using or treating finely-divided materials in dispersion
    • F27B15/02—Details, accessories or equipment specially adapted for furnaces of these types
    • F27B15/18—Arrangements of controlling devices
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
    • B01J—CHEMICAL OR PHYSICAL PROCESSES, e.g. CATALYSIS OR COLLOID CHEMISTRY; THEIR RELEVANT APPARATUS
    • B01J2208/00—Processes carried out in the presence of solid particles; Reactors therefor
    • B01J2208/00008—Controlling the process
    • B01J2208/00017—Controlling the temperature
    • B01J2208/00026—Controlling or regulating the heat exchange system
    • B01J2208/00035—Controlling or regulating the heat exchange system involving measured parameters
    • B01J2208/00044—Temperature measurement
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
    • B01J—CHEMICAL OR PHYSICAL PROCESSES, e.g. CATALYSIS OR COLLOID CHEMISTRY; THEIR RELEVANT APPARATUS
    • B01J2208/00—Processes carried out in the presence of solid particles; Reactors therefor
    • B01J2208/00008—Controlling the process
    • B01J2208/00017—Controlling the temperature
    • B01J2208/00106—Controlling the temperature by indirect heat exchange
    • B01J2208/00115—Controlling the temperature by indirect heat exchange with heat exchange elements inside the bed of solid particles
    • B01J2208/00132—Tubes
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
    • B01J—CHEMICAL OR PHYSICAL PROCESSES, e.g. CATALYSIS OR COLLOID CHEMISTRY; THEIR RELEVANT APPARATUS
    • B01J2208/00—Processes carried out in the presence of solid particles; Reactors therefor
    • B01J2208/00008—Controlling the process
    • B01J2208/00017—Controlling the temperature
    • B01J2208/0053—Controlling multiple zones along the direction of flow, e.g. pre-heating and after-cooling
    • 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 
    • F23C2206/00—Fluidised bed combustion
    • F23C2206/10—Circulating fluidised bed
    • F23C2206/101—Entrained or fast fluidised 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 
    • F23C2206/00—Fluidised bed combustion
    • F23C2206/10—Circulating fluidised bed
    • F23C2206/103—Cooling recirculating particles
    • Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
    • Y02—TECHNOLOGIES OR APPLICATIONS FOR MITIGATION OR ADAPTATION AGAINST CLIMATE CHANGE
    • Y02P—CLIMATE CHANGE MITIGATION TECHNOLOGIES IN THE PRODUCTION OR PROCESSING OF GOODS
    • Y02P10/00—Technologies related to metal processing
    • Y02P10/10—Reduction of greenhouse gas [GHG] emissions
    • Y02P10/134—Reduction of greenhouse gas [GHG] emissions by avoiding CO2, e.g. using hydrogen
    • Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
    • Y02—TECHNOLOGIES OR APPLICATIONS FOR MITIGATION OR ADAPTATION AGAINST CLIMATE CHANGE
    • Y02P—CLIMATE CHANGE MITIGATION TECHNOLOGIES IN THE PRODUCTION OR PROCESSING OF GOODS
    • Y02P10/00—Technologies related to metal processing
    • Y02P10/20—Recycling

Definitions

  • the present invention relates to a method and apparatus for controlling the temperature of exothermic processes, e.g. roasting of sulphide ores or burning processes, arranged to take place in a particle suspension in a circulating fluidized bed reactor.
  • the circulating fluidized bed reactor comprises: - a fluidized bed reactor, into which process feed material and gas are introduced, the gas being introduced through a grate provided at the bottom of the fluidized bed reactor, so that the solid material particles form a fast fluidized bed in the fluidized bed reactor, from which bed a considerable portion of the solid material particles is conveyed with the gas as a particle suspension into the upper portion of the fluidized bed, and is then withdrawn from the fluidized bed reactor via an outlet arranged at the upper portion of the fluidized bed reactor, - a particle separator, connected to the outlet at the upper portion of the fluidized bed reactor to separate solid material particles from gases and
  • the product can be withdrawn from the circulating fluidized bed reactor either continuously from the grate of the reactor or it is separated as fine dust from the flow of gas with e.g. an electrostatic precipitator.
  • zinc concentrate is roasted in e.g. a longitudinally elongated horizontal reactor, in which the roasting takes place in a slow or bubbling fluidized bed.
  • the coarse solid material is separated from flue gases in a cyclone and the fine dust in an electrostatic precipitator.
  • the roasted product from the reactor is cooled in a separate fluidized bed reactor.
  • a so-called vertical bubbling bed reactor is used for this purpose.
  • roasting temperature in a fluidized bed reactor is typically 900 - 1000°C. Utilizing e.g. the following ' alternative methods, this temperature can be maintained in a fluidized bed reactor: - providing the reactor with cooling surfaces in a way similar to the furnace of a conventional boiler.
  • cooling tubes be provided both in the fluidized bed itself as well as in the free board area above it; - utilizing the circulating fluidized bed technology, in which case the cooling surfaces can be arranged in the reactor as above, but also in communication with the external circulating mass, thereby continuously recycling externally cooled circulating material back into the fluidized bed.
  • the entire cooling can take place in the circulating mass, in an apparatus outside the reactor, thus eliminating any need for cooling surfaces in the reactor.
  • the roasting temperature is not usually regulated, but the air coefficient is utilized to achieve the desired roasting or combustion result.
  • the roasting temperature can not be optimized, but it is allowed to vary.
  • the result of this is that the plant will have to be run in a limited efficiency range, so that the temperature will be neither under nor above the limits for the practical combustion temperature range.
  • an optimal roasting or combustion result is achieved "by chance", and when other process conditions change (e.g. changes in the humidity of the concentrate, irregularities in the supply of material, changes in the composition of the concentrate), the result will also change. If both the air coefficient of the combustion and the combustion temperature could simultaneously be held constant, an optimal and uniform roasting result could be achieved at all times.
  • the object of the present invention is to provide for a method and apparatus, superior to the above, for simultaneously regulating both the air coefficient of the combustion and the combustion temperature.
  • Another object of the present invention is to provide for a method for essentially decreasing the above disadvantages in present roasting and combustion technology.
  • a further object of the present invention is to provide for an apparatus, advantageous both in function and size, for accomplishing and regulating roasting reactions.
  • the method for controlling the temperature in exothermic processes in a circulating fluidized bed reactor to ac ⁇ complish the above objects is characterized in that - the particle suspension flowing upwards in the fluidized bed reactor is arranged to flow through a venturi portion, thereby forming an upper fluidized bed above the venturi portion, the upper fluidized bed having a circulation of mass in common with the lower fluidized bed, situated below the venturi portion;
  • the upper fluidized bed is additionally provided with a circulation of mass of its own by recycling a portion of the particles separated in the particle separator to the fluidized bed reactor above the venturi portion while a second portion of the particles is recycled to the lower fluidized bed below the venturi portion;
  • the exothermic reactions in the fluidized bed reactor are arranged to take place in the lower fluidized bed, i.e. the main reaction chamber; - the particle suspension is cooled in the upper fluidized bed, i.e. the cooling chamber, with heat transfer surfaces arranged therein and that
  • the cooled particle suspension is directed from the upper fluidized bed to the particle separator.
  • the portion of separated and cooled particles recycled from the particle separator to the upper fluidized bed or cooling chamber is preferably sufficient to cool the flow of gas/solid material suspension from the lower reaction chamber, or the main reaction chamber, to a desired temperature before the flow ' reaches the heat transfer surfaces disposed in the cooling chamber.
  • the particle suspension can, when for example roasting sulphide ores, be cooled in the cooling chamber with circulating material to ⁇ 500°C and, subsequently, with heat transfer surfaces disposed in the cooling chamber, to ⁇ 350°C.
  • the portion of cooled solid material particles recycled to the lower fluidized bed, or the main reaction chamber is sufficient to maintain a desired temperature in the reaction chamber.
  • a roasting reactor can be regulated so that the temperature is kept suitable, at about 800 - 1000°C.
  • An apparatus according to the invention for controlling the temperature in a circulating fluidized bed reactor is characterized in that - a throttle means is arranged in the fluidized bed reactor to restrain the flow of particle suspension at the venturi portion when the particle suspension flows from the bottom portion of the fluidized bed reactor to the upper portion of the fluidized bed reactor and to divide the fluidized bed reactor into lower and upper portions;
  • a first recycling conduit is connected to the upper portion of the fluidized bed reactor for recycling solid particles from the particle separator to the upper portion of the fluidized bed reactor;
  • a second recycling conduit is connected to the lower portion of the fluidized bed reactor for recycling particles from the particle separator to the lower portion of the fluidized bed reactor and that
  • a heat transfer surface is arranged in the upper portion or cooling chamber of the fluidized bed reactor to recover heat from the fluidized bed in the upper portion.
  • the velocity of the gas in the circulating fluidized bed reactor is 2 - 10 m/s, preferably 5 - 10 m/s, so that a considerable portion of the particles in the fluidized bed reactor flows with the gas through the venturi portion to the upper portion of the fluidized bed reactor and from there further to the particle separator.
  • a fluidized bed reactor according to the invention is especially suitable for metallurgical processes, such as roasting of sulphidic concentrates.
  • the roasting temperature can then be regulated by the recycling of particles and with heat transfer surfaces to about 800 - 1000°C so that an optimal roasting result is achieved.
  • the final cooling of the flue gases after the roasting (or combustion), typically to about 200 - 500°C, takes place in a chamber above the venturi, i.e. the cooling chamber, the end temperature depending on e.g. the dewpoint of sulphur compounds.
  • a very fast first cooling to a temperature of e.g. ⁇ 500°C is achieved with the recirculation of the cooled mass, by which meta-stable stages of equilibrium can be achieved, e.g.
  • the gases are subsequently cooled to e.g. a temperature ⁇ 350°C with the heat transfer surfaces.
  • the still hot roasted product is withdrawn straight from the lower portion of the reaction chamber. It can also be withdrawn from the recycling conduit, from the cooled circulating material flow. A portion of the roasted product, especially the finest particles thereof, is conveyed with the flow of flue gases to a final dust separation to e.g. an electrostatic precipitator where it can be recovered.
  • the cooling of the particle suspension in the cooling chamber is preferably arranged to take place in two stages, so that
  • cooled particles recycled from the particle separator are mixed with the particle suspension flowing from the reaction chamber to the upper portion to rapidly lower the temperature to e.g. under 550°C, after which
  • the particle suspension is directed via the heat recovering surfaces provided in the cooling chamber, so that the suspension is cooled to the temperature at which the final dust separation is to take place, typically about 350°C.
  • the excess heat released during roasting is recovered with heat transfer surfaces arranged in both the reaction chamber and the cooling chamber. Heat can also be recovered with heat transfer surfaces arranged in the recycling conduit.
  • a preferable way to integrate the combustion or roasting stage with the gas cooling stage is to construct the chamber for cooling flue gases on top of the reaction chamber, the two chambers forming an integrated construction.
  • the throttle means separating the chambers from each other can be structurally like e.g. a conventional gas dividing grate or only one single opening connecting the chambers, the shape and cross-section of which are so chosen as to prevent the circulation of mass in the upper chamber from flowing directly down into the lower, i.e. reaction chamber, during the operation of the reactor.
  • the temperature is controlled with a combination of heat transfer surfaces and circulation of mass, so that necessary heat transfer surfaces are arranged in a reactor with an appropriately sized circulation of mass.
  • the circulation of mass can mainly be used for regulating the temperature in the reactor and the main of cooling, i.e. heat recovery, can be effected by heat transfer to the heat transfer surfaces in the reactor, unless the kinetics of the roassting reaction prevents this.
  • roasting can always be practised with an optimal air coefficient and the efficiency of roasting can also be controlled when needed.
  • the oxidation reactions have time to take place mainly completely in the roasting reactor. If the reaction time has to be increased, it can within the scope of this solution be accomplished by decreasing the cooling effect of the heat transfer surface in the reaction chamber and increasing the cooling effect of the circulation of mass, thus increasing the reaction time with circulation of mass.
  • a solution according to the invention also makes it possible to eliminate a separate cooler for the roasting.
  • the roasted product can be withdrawn from the circulation of mass through the recycling conduit, the roasted product having the same temperature as the flue gas, typically about 350°C .
  • a separate hot separator is not needed in the roasting reactor, as the particles are separated and recycled only after being cooled in the cooling reactor.
  • the separator can be manufactured of steel, because the temperature of the gas is low enough, under 400°C.
  • the so-called mixing temperature can be regulated to a desired level, e.g. 500°C, with its own circulation of mass.
  • the mixing temperature is the temperature of the incoming particle suspension in the cooling chamber after the particle suspension has been mixed with the circulation of mass in the cooling chamber and before it contacts the heat transfer surfaces.
  • the gas coming from the roasting stage can be cooled to this temperature very rapidly, which essentially decreases the risk of the roasted product being sulphatized, as has been disclosed above.
  • the figure illustrates a circulating fluidized bed reactor comprising a double-staged fluidized bed reactor 10, a particle separator 12 and a recycling conduit 14.
  • Fluidizing gas in this case air, is introduced into the reaction chamber through a grate 16 arranged at the bottom of the reaction chamber from airbox 18 with nozzles 20. Fluidizing gas is introduced so that the velocity of the gas in the reaction chamber is about 2 - 10 m/s.
  • a fluidized bed is formed in the reaction chamber by introducing therein zinc concentrate through conduit 22 and circulating particles, separated at the particle separator, through recycling conduit 24.
  • the lower portion i.e. reaction chamber 26 forms a roasting reactor, where the zinc concentrate is roasted in oxidizing conditions.
  • the cross-section of the flow in the reaction chamber is chosen to be such that a considerable portion of the solid material is conveyed with the flue gases formed therein into the upper portion of the fluidized bed reactor, i.e. the cooling chamber 28.
  • the particle suspension formed by the gases and solid material flows into the upper portion via a narrow venturi or opening 32 defined by throttle means 30.
  • the throttle means is arranged in the reactor so that the gases flowing upwards have to flow via an opening, the cross-section of which is smaller than that of the rest of the reactor.
  • the velocity of the gas in the opening 32 is so high that no particles can flow downwards through the venturi back to the reaction chamber 26. As the velocity of the gas flow decreases after the venturi, a second, upper fluidized bed is formed into the upper portion 28. However, the velocity of the gas is so high, 2 - 10 m/s, also in this fluidized bed that a considerable portion of particles is conveyed with the gas out from the fluidized bed reactor via an opening 33 arranged in the uppermost part of the reactor and further into the particle separator 12.
  • the particle separator illustrated in the figure is a vertical cyclone. Other kinds of separators, such as a horizontal cyclone or a filter, can naturally also be utilized.
  • the main portion of the solid material conveyed with the gas is separated from the gas, and the gas is directed via conduit 34 to the final particle separation to e.g. an electrostatic precipitator.
  • the separated particles are recycled via recycling conduit 14, partly through conduit 36 to the cooling chamber 28, partly through conduit 38 to the roasting reactor 26.
  • the roasted product is withdrawn through conduit 42 straight from the grate.
  • the roasted product can also, if desired, be withdrawn straight from the recycling conduit 14.
  • a heat transfer surface 44 is arranged in the roasting reactor 26 for recovering the heat formed in the reactor.
  • a second heat transfer surface 46 is correspondingly arranged in the cooling chamber 28 for cooling the particle suspension before the particle separator. Heat transfer surfaces 44 and 46 can be connected to the same heat recovery system. If desired, heat transfer surfaces 48 and 50 can also be arranged in the recycling conduit 14.
  • Controlling means 52 and 54 are arranged in recycling conduits 36 and 38 for controlling the recycling of solid material to the roasting reactor 26 and to the cooling chamber 28.
  • the temperature in the roasting reactor can be decreased by increasing the circulation of mass into the roasting reactor.
  • the temperature can correspondingly be increased by decreasing the amount of recycled circulating mass.
  • two fluidized beds 26 and 28 have simply been arranged in an integrated vertical structure.
  • an inexpensive and small integration of a roasting reactor and a cooling chamber can be formed.
  • the control system according to the invention can be utilized e.g. in the combustion of waste material or other halogen-containing fuel.
  • the combustion is arranged to take place in the combustion chamber in the first portion of the reactor and the resulting flue gases are then cooled quickly in the cooling chamber to minimize the amount of organic halogenized compounds. This is to minimize the "de novo" synthesis, i.e. the re-formation of dioxines, furans and other toxic 'chlorine compounds on the cooling surfaces.
  • Toxic chlorine compounds such as dioxines and furans form from chlorine compounds especially easily in the temperature range of 250 - 400°C. The gases are therefore cooled quickly over this temperature range.
  • the invention can also be applied to cooling of flue gases of other metallurgical process, having gases in which chlorinated organic compounds can form during the cooling phase.
  • the aim is especially to avoid the forming of so- called super-toxins, i.e. polychlorinated dioxins and furans.
  • Emissions are further decreased by the condensation of the compounds in question on the surface of the particulate bed material, caused by the cooling.
  • a concentration level of the above and other organic compounds is formed in the bed material of the cooling chamber. This level can be controlled by recycling a portion of the material circulating in the cooling chamber to the lower reactor, acting as the combustion chamber.
  • the organic compounds condensated on the surface of the circulating material are combusted in the combustion chamber and the recycled material is cleaned.
  • the cleaned circulating material is returned to the cooling chamber, where it replaces the contaminated material, thus reducing the concentration of detrimental materials in the cooling chamber. This is desirable e.g. on the standpoint of further treatment of the material withdrawn from the reactor.

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  • Chemical & Material Sciences (AREA)
  • Engineering & Computer Science (AREA)
  • Combustion & Propulsion (AREA)
  • Mechanical Engineering (AREA)
  • Organic Chemistry (AREA)
  • General Engineering & Computer Science (AREA)
  • Chemical Kinetics & Catalysis (AREA)
  • Dispersion Chemistry (AREA)
  • Materials Engineering (AREA)
  • Manufacturing & Machinery (AREA)
  • Metallurgy (AREA)
  • Physics & Mathematics (AREA)
  • Thermal Sciences (AREA)
  • Devices And Processes Conducted In The Presence Of Fluids And Solid Particles (AREA)

Abstract

Le procédé et l'appareil décrits servent à réguler la température des processus exothermiques dans les réacteurs à lit fluidisé. Un venturi (30) est disposé à cet effet dans le réacteur à lit fluidisé en circulation, à travers lequel une suspension de particules s'écoule de la partie inférieure (28) vers la partie supérieure (28) du réacteur, de sorte qu'un lit fluidisé se forme à la fois dans la partie supérieure et dans la partie inférieure du réacteur. Les particules provenant de la suspension de particules, extraite de la partie supérieure du réacteur, sont séparées dans un séparateur de particules (12). Une partie des particules séparées dans le séparateur de particules est recyclée dans le lit fluidisé inférieur et une autre partie dans le lit fluidisé supérieur.
PCT/FI1991/000384 1990-12-21 1991-12-13 Procede et appareil de regulation de la temperature pour reacteur a lit fluidise en circulation Ceased WO1992011499A1 (fr)

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AU90439/91A AU652204B2 (en) 1990-12-21 1991-12-13 Method and apparatus for controlling temperature in a circulating fluidized bed reactor

Applications Claiming Priority (2)

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FI906347 1990-12-21
FI906347A FI89944C (fi) 1990-12-21 1990-12-21 Foerfarande och anordning foer reglering av temperaturen i en reaktor med cirkulerande fluidiserad baedd

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WO1992011499A1 true WO1992011499A1 (fr) 1992-07-09

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CA (1) CA2098577A1 (fr)
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WO (1) WO1992011499A1 (fr)

Cited By (6)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
WO1994025148A1 (fr) * 1993-05-04 1994-11-10 Allan Wesley Ah Shay Reacteur thermique a multietages a lit fluidise circulant tourbillonnaire
EP1247567A1 (fr) * 2001-04-02 2002-10-09 Einco Oy Methode pour réguler la température d'une réaction au sein d'un lit fluidisé
WO2010049619A1 (fr) * 2008-10-30 2010-05-06 Jean-Xavier Morin Dispositif de lit fluidise a fluidisation rapide et a flux sature de solides circulants
CN101579601B (zh) * 2009-06-12 2011-05-18 山西晋丰环保工程设计有限公司 文丘里环传质层吸收塔
EP2642199A1 (fr) * 2012-03-20 2013-09-25 Alstom Technology Ltd Chaudière à lit fluidisé à circulation
CN109058958A (zh) * 2018-06-13 2018-12-21 陈燕燕 一种锅炉炉体

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DE1041252B (de) * 1953-04-27 1958-10-16 Metallgesellschaft Ag Verfahren zum Betrieb von Wirbelschichtroestoefen unter automatischer Steuerung
DE1083058B (de) * 1959-07-10 1960-06-09 Schmidt Sche Heissdampf Verfahren zum Reinhalten der Heizflaechen von Abhitzekesseln und Einrichtung zur Durchfuehrung des Verfahrens
US4042376A (en) * 1975-01-24 1977-08-16 Stora Kopparbergs Bergslags Aktiebolag Method for carrying out endothermic reduction processes in a circulating fluid bed and an apparatus therefor
EP0003117A2 (fr) * 1978-01-12 1979-07-25 Battelle Development Corporation Lit fluidisé à deux zones pour la combustion ou la gazéification
US4323018A (en) * 1979-06-15 1982-04-06 Hokkaido Sugar Co., Ltd. Method for generation of hot gas by incineration of combustile material and apparatus for generation of hot gas by incineration of combustible material
EP0093063A1 (fr) * 1982-04-28 1983-11-02 Creusot-Loire Procédé et dispositif de contrôle de la température d'une réaction réalisée en lit fluidisé
US4799937A (en) * 1986-01-22 1989-01-24 A. Ahlstrom Corp. Method and apparatus for gasifying carbonaceous material
US4896631A (en) * 1985-06-13 1990-01-30 Aalborg Vaerft A/S Fluidized bed reactor

Patent Citations (8)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
DE1041252B (de) * 1953-04-27 1958-10-16 Metallgesellschaft Ag Verfahren zum Betrieb von Wirbelschichtroestoefen unter automatischer Steuerung
DE1083058B (de) * 1959-07-10 1960-06-09 Schmidt Sche Heissdampf Verfahren zum Reinhalten der Heizflaechen von Abhitzekesseln und Einrichtung zur Durchfuehrung des Verfahrens
US4042376A (en) * 1975-01-24 1977-08-16 Stora Kopparbergs Bergslags Aktiebolag Method for carrying out endothermic reduction processes in a circulating fluid bed and an apparatus therefor
EP0003117A2 (fr) * 1978-01-12 1979-07-25 Battelle Development Corporation Lit fluidisé à deux zones pour la combustion ou la gazéification
US4323018A (en) * 1979-06-15 1982-04-06 Hokkaido Sugar Co., Ltd. Method for generation of hot gas by incineration of combustile material and apparatus for generation of hot gas by incineration of combustible material
EP0093063A1 (fr) * 1982-04-28 1983-11-02 Creusot-Loire Procédé et dispositif de contrôle de la température d'une réaction réalisée en lit fluidisé
US4896631A (en) * 1985-06-13 1990-01-30 Aalborg Vaerft A/S Fluidized bed reactor
US4799937A (en) * 1986-01-22 1989-01-24 A. Ahlstrom Corp. Method and apparatus for gasifying carbonaceous material

Cited By (12)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
WO1994025148A1 (fr) * 1993-05-04 1994-11-10 Allan Wesley Ah Shay Reacteur thermique a multietages a lit fluidise circulant tourbillonnaire
EP1247567A1 (fr) * 2001-04-02 2002-10-09 Einco Oy Methode pour réguler la température d'une réaction au sein d'un lit fluidisé
US6612250B2 (en) 2001-04-02 2003-09-02 Einco Oy Method of controlling the temperature of a reaction carried out in a fluidised bed reactor
WO2010049619A1 (fr) * 2008-10-30 2010-05-06 Jean-Xavier Morin Dispositif de lit fluidise a fluidisation rapide et a flux sature de solides circulants
FR2937886A1 (fr) * 2008-10-30 2010-05-07 Jean Xavier Morin Dispositif de lit fluidise a fluidisation rapide et a flux sature de solides circulants
CN101579601B (zh) * 2009-06-12 2011-05-18 山西晋丰环保工程设计有限公司 文丘里环传质层吸收塔
EP2642199A1 (fr) * 2012-03-20 2013-09-25 Alstom Technology Ltd Chaudière à lit fluidisé à circulation
WO2013140332A1 (fr) * 2012-03-20 2013-09-26 Alstom Technology Ltd Chaudière à lit fluidisé circulant
KR20140138298A (ko) * 2012-03-20 2014-12-03 알스톰 테크놀러지 리미티드 순환 유동층 보일러
CN104204666A (zh) * 2012-03-20 2014-12-10 阿尔斯通技术有限公司 循环流化床锅炉
KR102052140B1 (ko) * 2012-03-20 2019-12-05 제네럴 일렉트릭 테크놀러지 게엠베하 순환 유동층 보일러
CN109058958A (zh) * 2018-06-13 2018-12-21 陈燕燕 一种锅炉炉体

Also Published As

Publication number Publication date
FI906347L (fi) 1992-06-22
FI89944B (fi) 1993-08-31
AU9043991A (en) 1992-07-22
AU652204B2 (en) 1994-08-18
FI906347A0 (fi) 1990-12-21
FI89944C (fi) 1993-12-10
CA2098577A1 (fr) 1992-06-22

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