US3847092A - Automatic bed level control for furnaces - Google Patents

Automatic bed level control for furnaces Download PDF

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Publication number
US3847092A
US3847092A US00423645A US42364573A US3847092A US 3847092 A US3847092 A US 3847092A US 00423645 A US00423645 A US 00423645A US 42364573 A US42364573 A US 42364573A US 3847092 A US3847092 A US 3847092A
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Prior art keywords
furnace
bed
light
level
primary air
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Expired - Lifetime
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US00423645A
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English (en)
Inventor
L Gilbert
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Combustion Engineering Inc
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Combustion Engineering Inc
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Priority to US00423645A priority Critical patent/US3847092A/en
Application granted granted Critical
Publication of US3847092A publication Critical patent/US3847092A/en
Priority to CA214,961A priority patent/CA1057910A/en
Priority to JP49140587A priority patent/JPS5217346B2/ja
Priority to FR7440312A priority patent/FR2253995B1/fr
Priority to SE7415415A priority patent/SE413159B/xx
Priority to FI3558/74A priority patent/FI56984C/fi
Priority to ES432986A priority patent/ES432986A1/es
Anticipated expiration legal-status Critical
Expired - Lifetime legal-status Critical Current

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    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F23—COMBUSTION APPARATUS; COMBUSTION PROCESSES
    • F23N—REGULATING OR CONTROLLING COMBUSTION
    • F23N5/00—Systems for controlling combustion
    • F23N5/02—Systems for controlling combustion using devices responsive to thermal changes or to thermal expansion of a medium
    • F23N5/08—Systems for controlling combustion using devices responsive to thermal changes or to thermal expansion of a medium using light-sensitive elements
    • F23N5/082—Systems for controlling combustion using devices responsive to thermal changes or to thermal expansion of a medium using light-sensitive elements using electronic means
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F23—COMBUSTION APPARATUS; COMBUSTION PROCESSES
    • F23G—CREMATION FURNACES; CONSUMING WASTE PRODUCTS BY COMBUSTION
    • F23G5/00—Incineration of waste; Incinerator constructions; Details, accessories or control therefor
    • F23G5/50—Control or safety arrangements
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F23—COMBUSTION APPARATUS; COMBUSTION PROCESSES
    • F23G—CREMATION FURNACES; CONSUMING WASTE PRODUCTS BY COMBUSTION
    • F23G7/00—Incinerators or other apparatus for consuming industrial waste, e.g. chemicals
    • F23G7/04—Incinerators or other apparatus for consuming industrial waste, e.g. chemicals of waste liquors, e.g. sulfite liquors
    • 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
    • F23K3/22—Controlling thickness of fuel bed

Definitions

  • An automatic bed level control system for furnaces which burn a material on a bed, such as chemicalrecovery furnaces and the like.
  • Optical sensing means sense light emitted by the burning of the bed material and provide a signal which varies as a function of the intensity of the sensed light.
  • the sensing means are structured and oriented to respond to light emanating only from a particular, vertically limited zone in the furnace, such that variations in the intensity of the sensed light are indicative of variations in bed level.
  • the signal provided by the sensing means is then used to regulate some bed level controlling parameter, as for instance primary air flow.
  • the invention relates to furnaces which burn fuel in a bed. More particularly it relates to a method and apparatus for controlling the depth or level of the bed in a furnace. More particularly still it relates to a method and apparatus for utilizing the light associated with burning on the bed to regulate a variable which affects bed depth.
  • the control of the level or depth of the bed in furnaees may be quite important in optimizing the burning function of the furnace.
  • the bed is the accumulation of various fuels and other materials which reside on a floor or grate in the furnace and is burned, either to reduce its overall solid mass or to effect certain chemical changes or both.
  • a particularly good example of the need to control bed depth is seen in chemical recovery furnaces.
  • the control of the operating conditions in the lower furnace controls the reduction of the sodium sulfate to the sodium sulfide and conversion of sodium carbonate to sodium oxide and sodium oxide to sodium vapor.
  • the amount of sodium vapor formed byreduction in turn controls the concentration of sulfur oxides and the sodium sulfate and sodium carbonate fume emitted in flue gas from the furnace.
  • Proper control of the burning, and particularly reducing, conditions is therefore necessary not only to regulate the efficiency of the production of sodium sulfide from sodium sulfate, but also to regulate furnace emissions. Increased steam production is an additional benefit of correct operation.
  • a high bed burning temperature and a relatively deep char bed in the furnace are desirable to maximize reduction efficiency and to decrease sulfur oxide and particulate (fume) emission.
  • furnace operators are often reluctant to operate with a deep char bed because it requires continuous attention and adjustment of the primary air dampers.
  • Another disadvantage of operating with an excessively deep char bed is that the air ports around the periphery of the furnace can become blocked, causing a blackout when an undercut char bed falls over toward a furnace wall.
  • a further problem with deep bed operation is that it is often difficult to determine by mere visual observation the exact height of the bed and, therefore, difficult to tell if the bed is getting too deep.
  • This preferred bed level will tend to have an angle of repose of some 40 to with its base some 8-12 inches below the primary air ports.
  • the angle of repose of an excessively high bed will exceed 50 and its base will be only an inch or two below the primary air port.
  • the angle of repose of a bed is less than 40 and its base more than 12 inches below the primary air ports, the bed is too low for the most efficient reduction.
  • the present invention involves a technique and means for controlling the level or depth of the bed in a furnace, such as a chemical recovery furnace.
  • a furnace such as a chemical recovery furnace.
  • the invention provides means for and a method of sensing the intensity of light emanating from the furnace, particularly light only from a zone of limited vertical extent, and using it to provide a control signal which is operative to vary one or more of the bed level controlling variables as a function of the sensed lights intensity.
  • Optical sensing means preferably having a limited vertical sight angle within the furnace, is effective to control one or moreofthe bed level controlling variables, as for instance air flow. This may be done by con trolling dampers in primary air ducts.
  • the sensing means is preferably positioned to view the bed and furnace interior through the primary air ports.
  • the sensing means may be responsive to light of one or more wavelengths emanating from the furnace as a result of burning gases from the bed, though selective sensing of light of a single wavelength, such as emitted by excited sodium atoms in a chemical recovery furnace, may be preferred.
  • Plural optical sensing means positioned to view the furnace interior at various positions around the bed, each associated with a different regional primary air supply and damper,'provide a preferred means for controlling bed level.
  • FIG. 1 is a schematic elevational view of a black liquor chemical recovery furnace incorporating the present invention.
  • FIG. 2a is a somewhat diagrammatic elevational view of the furnace with the char bed at a preferred level.
  • FIG. 2b is a somewhat diagrammatic elevational view of the furnace showing an excessively high char bed.
  • FIG. 20 is a somewhat diagrammatic elevational view of the furnace showing an excessively low or shallow char bed.
  • FIG. 3 is an enlarged view of a portion of FIG. 1, schematically depicting the optical sensor, the primary air damper and the control circuitry and actuator connected therebetween.
  • FIG. 4 is an elevational sectional view taken along line 4--4 of FIG. 3 to approximate the view of and through the primary air ports by the optical sensor.
  • FIG. 5 is a schematic cross-sectional view taken along line 55 of FIG. 1.
  • FIG. l Illustrates a chemical recovery furnace which is typical of chemical recovery furnaces used for the processing of black liquor.
  • the walls of this furnace are lined with steam generating tubes 12 which form a part of the heat exchange surface of the chemical recovery unit with there being additional heat exchange surface identified generally at 14 in the upper region of the unit.
  • Black liquor obtained from the kraft pulping process and/or other sodium based pulping processes which has been processed by evaporation to the desired solids content is introduced into the furnace 10 through the nozzles 16.
  • the liquor thus sprayed into the furnace descends downwardly towards the furnace bottom passing through rising combustion gas such that a majority of the moisture in the liquor is immediately evaporated.
  • the solid particles fall downwardly through this rising combustion gas stream and form a pile or char bed 18 on the hearth or furnace bottom 20.
  • a portion of the combustibles are consumed during this descent through the furnace with remaining combustibles being consumed in the char bed 18.
  • the noncombustibles, inorganic chemicals, are smelted and decanted from the furnace through the discharge spout 22.
  • Combustion-supporting air is introduced into the furnace at two locations.
  • the primary air is introduced through nozzles or ports 24 spaced relatively close to the bottom while the secondary air is introduced through the nozzles or ports 26 located above the liquor nozzles 16.
  • This yellow light comes from the thermal excitation of sodium atoms in the extremely fine, hot solid particles of Na O fume. It has sharp peaks of intensity in the 5,890 Angstrom wavelength region of the visible light spectrum. This wavelength is characteristic of sodium either in the elemental or compound form. Other gases or vapors may also be evolved, contributing their characteristic spectral emissions to the light emitted on and above the char bed. This light may be both in and/or near the visual range and is typified by, though not limited to, the sodium spectral emissions. This light generally originates at the surface of and just above char bed 18 and is represented in the drawings, such as FIGS. 2a, 2b and 20, by the shimmering waveform 27.
  • Light waveform 27 indicates the region in which the light originates and the amplitude of its oscillations provide a relative indication of the light intensity thereat, the light generally covering most of the bed and being of greatest intensity near the center and fading away from the center at the cooler side areas.
  • FIGS. 2a, 2b and 2c respectively, depict char bed 18 having a preferred level or depth, an excessively high level and an excessively low level.
  • the preferred bed will have an angle of repose between 40 and 50 and its base will be some 8-12 inches below the primary air ports 24;
  • the excessively high bed of FIG. 2b will have an angle of repose exceeding 50 and its base will be at or an inch or two below ports 24;
  • the low bed of FIG. 2c will have an angle of repose less than 40 and its base will be 12-18 inches or more below ports 24.
  • the meter 28 for use in the present invention to receive and indicate the intensity of the photon energy emitted by burning gas or gases from bed 18 is an optical device substantially as described in the aforementioned application.
  • meter 28 will include a photodetector of some well known type, such as a photoresistor, photodiode, phototransistor, photomultiplier or the like.
  • the photodetector may be of a type responsive to a particular portion of the visible light spectrum, such as the portion including the sodium spectral emissions or it may be broader in range to include the full visible spectrum and possibly beyond.
  • Appropriate filters, prisms, diffraction gratings or the like might also be used to restrict the sensed light to a certain portion of the spectrum. Because most of the light in chemical recovery furnace is in the sodium region of the spectrum, it is desirable that the meter 28 be responsive to such light.
  • Meter 28 is positioned and oriented such that it views a particular zone within furnace 10.
  • the horizontal or azimuthal extent of the field of view of a meter 28 is not particularly critical, but should include a representative portion of char bed 18.
  • At least one meter 28 should be positioned at each of the four sides of furnace 10, and preferably one with each of the primary air ducts 29, as seen in FIG. 5 and described hereinafter.
  • the vertical field of view of a meter 28 is, however, somewhat more critical and should be restricted to a zone, indicated by dotted lines 30 in FIGS. 2a, 2b and 20, which does not include the full vertical range of the light waveform 27 between the high bed level of FIG. 2b and the low bed level of FIG. 2c.
  • meter 28 it is desirable that the positioning of meter 28 be such that changes in the bed level cause maximum changes in the intensity of the light sensed by it. This may be accomplished by positioning and orienting meter 28 such that it sights in a substantially horizontal direction and its vertical angle or extent of view is limited to satisfy the requirement mentioned above.
  • the upper side of the field of view 30 is such that most of the light waveform 27 for a high bed, as in FIG. 2b, is excluded from view; more of the light waveform 27 for an intermediate, and in this case, bed level as in FIG. 2a, is included in the vertical field of view; and still more of the light waveform 27 for a low bed level, as in FIG. 20, is included in the vertical zone or field of view.
  • the field of view of meter 28 is such that an indication of low sensed light intensity is indicative of a high bed level; and indicationof high sensed light intensity is indicative of a low bed level; and an indication of an intermediate sensed light intensity indicates a bed level in between.
  • the indication may be calibratd against known or observed bed levels. While other conditions affect light intensity somewhat at any given bed level, the effects are minimal and the control response to be discussed is in the correct direction.
  • the meter 28 is preferably mounted on primary air duct 29 such that it is outside observation window 32 and is oriented to sight through the window and the air ports 24 at char bed 18. In this configuration the air ports 24 determine the zone viewed within furnace 10. Similarly, because calibrated of the spacing between meter 28 and air ports 24 and the vertical extent of the air ports in a typical furnace 10, the upper extent of the field of view in the furnace is held below most of light waveform 27 in the high bed condition of FIG. 2b. Air
  • duct 29 and air ports 24 serve as a form of collimator for meter 28, however it will be appreciated that other collimating means might be used and that the meter might be located elsewhere with similar limitations on the zone viewed within the furnace.
  • Light conductors such as optical pipes or fibers, might be used to conduct light from the furnace wall to a remote sensor.
  • Primary air flow is a parameter which is largely responsible for controlling the level of bed 18 and is relatively easy to vary.
  • a damper 34 in each of the primary air ducts 29 is operative to control the rate of flow of primary air through its associated air duct. While such control has previously been of a manual nature and in response to occassional viewing of the bed 18 through window 32 by the operator, the invention utilizes meter 28 as means for providing a signal which serves to automatically control an actuator connected to damper 34. In this manner, accurate, continuous automatic control of the level of char bed 18 is effected.
  • FIG. 3 there is a somewhat diagrammatic schematical view of furnace 10, optical meter 28, primary air damper 34, damper actuating means such as cylinder 54 and rod 58, and the control circuitry intermediate the meter and the actuating means.
  • Meter 28 is shown as including a photodetector represented by variable resistor 38.
  • the photodetector will exhibit a characteristic, i.e., resistance change, which varies as a function of the intensity of light sensed.
  • the detector might alternately exhibit a voltage or current change. While the photodetector might be part of a bridge circuit, it is shown here singly providing a light intensity signal for simplicity.
  • Control unit 40 typically includes an operational amplifier and a power switch.
  • a set point signal is developed from potentiometer 42 and is applied as another input to control unit 40.
  • the set point signal and the light intensity signal will typically be of opposite polarity and the magnitude of the set point signal will be set at that value commensurate with the magnitude of the signal from meter 28 during optimun or preferred char bed level conditions.
  • the power switch portion of control unit 40 is operatively connected to the operational amplifier and includes a three position, three terminal switch, one terminal being connected by conductor 44 to the solenoid of valve 46 and another terminal being connected by conductor 48 to the solenoid of valve 50.
  • the common of the switch being connected to a source of power.
  • Both valves 46 and 50 are connected in a pneumatic circuit between air supply 52 and pneumatic cylinder 54.
  • a pressure reducing valve 56 is also included in the pneumatic circuit. Valves 46 and 50 are normally closed when the switch is in its neutral third position andare opened only when the switch closes the electrical circuit to the particular valve solenoid, only one valve being open at a time.
  • Cylinder 54 is pivotably mounted to some support structure at one end and piston rod 58 extends from the other end. Piston rod 58 is connected to damper actuating linkage 60 which in turn is connected to damper 34. Linkage 60 may, at least in part, comprise the existing manual control linkage for the damper. Movement of piston rod 58 results in rotation of damper 34, to proportionally control the air between fully open (maximum air flow) and fully closed (no air flow). Means other than pneumatic cylinder 54, suchas a motor or diaphragm, might be used to actuate damper 34.
  • Position indicating linkage 62 is rigidly connected at one end to piston rod 58 and at the other end to a rotary potentiometer 64.
  • Potentiometer 64 has a voltage applied thereto and its wiper is connected through capacitor 66 by conductor 68 to another input of the operational amplifier of control unit 40.
  • the signal provided by potentiometer 64 and capacitor 66 is a form of derivative feedback.
  • the polarity of the voltage on potentiometer 64 and the direction of rotation of the potentiometer relative to the direction of motion of pis ton rod 58 are selected such that a feedback signal voltage is applied to the operational amplifier input during actuation of cylinder 54.
  • This feedback signal is temporarily effective to cancel the difference between the set point signal and the control signal from meter 28, resulting in closure of both valves 46 and 50 and cessa tion of movement of piston rod 58.
  • the derivative feedback produces an integrating action for the damper position.
  • the movement of rod 58 is effective, through linkage 62, to rotate potentiometer 64 a certain amount, changing the voltage applied to capacitor 66 and resulting in a dv/dt voltage applied to control unit 40 to momentarily cancel the input error to the operational amplifier, thereby opening the circuit to the solenoid for valve 46 and thus closing the valve.
  • the dv/a'i voltage is removed when movement of rod 58 stops, allowing any remaining error to once again open valve 46. This operation is repeated with attendant short steps of damper 34 until the error signal is removed by a change in bed level and sensed brightness or until the damper is full open, the latter ultimately producing the former.
  • While the bed level control system just described was associated with a single primary air duct 29, it will be appreciated that at least one such arrangement would exist at each of the four sides of the furnace 10. If there is more than one duct 29 at each side of the furnace, one meter 28 per side might be used to control the several dampers 34 for that side. Alternatively, as seen in FIG. 5, a separate meter 28 might be associated with each duct 29 and its damper 34. Still further, if regional control of char bed depth is not required, the control signals from the several meters 28 may be averaged and the resultant used to control all of the dampers 34.
  • the described embodiment of the invention was in use in a chemical recovery boiler, it will be similarly applicable to incinerators and other furnaces having beds for sensing light intensity as an indicator of bed depth and regulating a control variable accordingly.
  • the photodetector might be similarly oriented to view the bed with a vertically limited angle of view, but might respond to a broader range of optical wavelengths or else that or those characteristic of burning carbon or hydrocarbons.
  • some other parameter or parameters than just primary air might be controlled to regulate-bed depth, however the latter is generally preferred.
  • means for controlling the level of said bed comprising:
  • sensing means sense light only from a particular zone in said furnace such that the intensity of said sensed light is related to the level of the bed with respect to the point of measurement.
  • said primary air flow varying means include a damper and said signal responsive means further include an actuator operatively connected to said damper and responsive to said signal from said light sensor for varying the position of said damper in a direction to maintain said sensed light at a desired value commensurate with a desired bed level.
  • each said air duct includes an air port at its downstream end and each said associated light sensing means views the interior of said furnace through said air port.
  • said furnace is a chemical recovery furnace; said material being burned includes a sodium compound and said light includes a wavelength characteristic of excited sodium atoms; and said sensing means is responsive only to said light wavelength characteristic of excited sodium atoms.
  • said furnace is a chemical recovery furnace; said material being burned includes a sodium compound and said light includes a wavelength characteristic of excited sodium atoms; and said sensing means is responsive only to said light wavelength characteristic of excited sodium atoms.
  • a method for controlling the level of said char bed comprising the steps of:
  • said material being burned includes a sodium compound and said light includes a wavelength characteristic of excited sodium atoms and wherein said step of sensing said light includes sensing only that light having a wavelength characteristic of excited sodium atoms, whereby said control signal is indicative only of the intensity of said light wavelength characteristic of excited sodium

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  • Engineering & Computer Science (AREA)
  • Mechanical Engineering (AREA)
  • General Engineering & Computer Science (AREA)
  • Chemical & Material Sciences (AREA)
  • Combustion & Propulsion (AREA)
  • Environmental & Geological Engineering (AREA)
  • Incineration Of Waste (AREA)
  • Gasification And Melting Of Waste (AREA)
  • Paper (AREA)
  • Control Of Combustion (AREA)
US00423645A 1973-12-10 1973-12-10 Automatic bed level control for furnaces Expired - Lifetime US3847092A (en)

Priority Applications (7)

Application Number Priority Date Filing Date Title
US00423645A US3847092A (en) 1973-12-10 1973-12-10 Automatic bed level control for furnaces
CA214,961A CA1057910A (en) 1973-12-10 1974-11-29 Automatic bed level control for furnaces
JP49140587A JPS5217346B2 (fi) 1973-12-10 1974-12-09
FR7440312A FR2253995B1 (fi) 1973-12-10 1974-12-09
SE7415415A SE413159B (sv) 1973-12-10 1974-12-09 Sett och anordning for reglering av nivan av bedden i en eldstad
FI3558/74A FI56984C (fi) 1973-12-10 1974-12-10 Saett vid drift av en eldstad och anordning foer utoevande av detta saett
ES432986A ES432986A1 (es) 1973-12-10 1974-12-10 Perfeccionamiento y aparato para el control automatico del nivel del lecho en los hornos.

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US00423645A US3847092A (en) 1973-12-10 1973-12-10 Automatic bed level control for furnaces

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US3847092A true US3847092A (en) 1974-11-12

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US (1) US3847092A (fi)
JP (1) JPS5217346B2 (fi)
CA (1) CA1057910A (fi)
ES (1) ES432986A1 (fi)
FI (1) FI56984C (fi)
FR (1) FR2253995B1 (fi)
SE (1) SE413159B (fi)

Cited By (10)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US4080784A (en) * 1974-10-17 1978-03-28 Rolls-Royce Limited Gas turbine engine power plant with a coal burning fluidized bed
US4241672A (en) * 1978-12-04 1980-12-30 The United States Of America As Represented By The United States Department Of Energy Method of regulating the amount of underfire air for combustion of wood fuels in spreader-stroke boilers
US4389283A (en) * 1980-10-29 1983-06-21 Albert Calderon Method for making coke via induction heating
US4513671A (en) * 1984-07-20 1985-04-30 Eshland Enterprises, Inc. Particle fuel delivery control device
US4748004A (en) * 1986-02-13 1988-05-31 Goodspeed Byron Lester Apparatus for cleaning air ports of a chemical recovery furnace
US4768469A (en) * 1985-07-31 1988-09-06 Kabushiki Kaisha Toshiba Operation control apparatus for recovery boilers
NL1027661C2 (nl) * 2004-12-06 2006-06-07 Nem Energy Services B V Luchtregeling.
US20090139468A1 (en) * 2004-11-04 2009-06-04 Andritz Oy Control of a recovery boiler or alike
ITUB20160989A1 (it) * 2016-02-23 2017-08-23 Stefano Salvatico Apparato di combustione
AT525374B1 (de) * 2021-08-17 2023-12-15 Valmet Automation Oy Verfahren zur steuerung eines chemikalienrückgewinnungskessels und ein chemikalienrückgewinnungskessel

Families Citing this family (4)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JPS51118128A (en) * 1975-04-10 1976-10-16 Mitsubishi Heavy Ind Ltd Monitering apparatus for combustion state of boiler black waste
JPS58141600A (ja) * 1982-02-17 1983-08-22 松下電器産業株式会社 プリント基板搬送装置
IT1155658B (it) * 1982-03-23 1987-01-28 Fata Ind Spa Sistema e metodo per il recupero delle sabbie contenute in forme ed anime di fonderia mediante calcinazione in un forno a letto fluidizzato
RU2070688C1 (ru) * 1987-05-01 1996-12-20 Ибара Корпорейшн Способ управления горением в печи для сжигания отходов в псевдоожиженном слое

Citations (4)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US3477823A (en) * 1964-12-30 1969-11-11 Combustion Eng Chemical recovery unit
US3607117A (en) * 1969-07-28 1971-09-21 Rust Engineering Co Black liquor recovery boiler combustion and safety control system
US3625186A (en) * 1970-08-11 1971-12-07 Rust Engineering Co The Control system for firing black liquor recovery boiler auxiliary fuel in response to plant load swings
US3765377A (en) * 1972-06-23 1973-10-16 Combustion Eng Air pollution control system for chemical recovery unit

Patent Citations (4)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US3477823A (en) * 1964-12-30 1969-11-11 Combustion Eng Chemical recovery unit
US3607117A (en) * 1969-07-28 1971-09-21 Rust Engineering Co Black liquor recovery boiler combustion and safety control system
US3625186A (en) * 1970-08-11 1971-12-07 Rust Engineering Co The Control system for firing black liquor recovery boiler auxiliary fuel in response to plant load swings
US3765377A (en) * 1972-06-23 1973-10-16 Combustion Eng Air pollution control system for chemical recovery unit

Cited By (14)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US4080784A (en) * 1974-10-17 1978-03-28 Rolls-Royce Limited Gas turbine engine power plant with a coal burning fluidized bed
US4241672A (en) * 1978-12-04 1980-12-30 The United States Of America As Represented By The United States Department Of Energy Method of regulating the amount of underfire air for combustion of wood fuels in spreader-stroke boilers
US4389283A (en) * 1980-10-29 1983-06-21 Albert Calderon Method for making coke via induction heating
US4513671A (en) * 1984-07-20 1985-04-30 Eshland Enterprises, Inc. Particle fuel delivery control device
US4768469A (en) * 1985-07-31 1988-09-06 Kabushiki Kaisha Toshiba Operation control apparatus for recovery boilers
US4748004A (en) * 1986-02-13 1988-05-31 Goodspeed Byron Lester Apparatus for cleaning air ports of a chemical recovery furnace
US7831084B2 (en) * 2004-11-04 2010-11-09 Andritz Oy Control of a recovery boiler or alike
US20090139468A1 (en) * 2004-11-04 2009-06-04 Andritz Oy Control of a recovery boiler or alike
EP1666794A1 (en) * 2004-12-06 2006-06-07 NEM Energy Services B.V. Air control
NL1027661C2 (nl) * 2004-12-06 2006-06-07 Nem Energy Services B V Luchtregeling.
ITUB20160989A1 (it) * 2016-02-23 2017-08-23 Stefano Salvatico Apparato di combustione
AT525374B1 (de) * 2021-08-17 2023-12-15 Valmet Automation Oy Verfahren zur steuerung eines chemikalienrückgewinnungskessels und ein chemikalienrückgewinnungskessel
AT525374A3 (de) * 2021-08-17 2023-12-15 Valmet Automation Oy Verfahren zur steuerung eines chemikalienrückgewinnungskessels und ein chemikalienrückgewinnungskessel
US12104319B2 (en) 2021-08-17 2024-10-01 Valmet Automation Oy Method for controlling a chemical recovery boiler and a chemical recovery boiler

Also Published As

Publication number Publication date
FI56984C (fi) 1980-05-12
FR2253995A1 (fi) 1975-07-04
JPS5217346B2 (fi) 1977-05-14
JPS5090156A (fi) 1975-07-19
CA1057910A (en) 1979-07-10
ES432986A1 (es) 1977-02-16
SE413159B (sv) 1980-04-21
FI56984B (fi) 1980-01-31
FR2253995B1 (fi) 1978-09-22
FI355874A (fi) 1975-06-11
SE7415415L (fi) 1975-06-11

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