US3647195A - Apparatus for and method of controlling rotary kiln operation - Google Patents

Apparatus for and method of controlling rotary kiln operation Download PDF

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Publication number
US3647195A
US3647195A US33811A US3647195DA US3647195A US 3647195 A US3647195 A US 3647195A US 33811 A US33811 A US 33811A US 3647195D A US3647195D A US 3647195DA US 3647195 A US3647195 A US 3647195A
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Prior art keywords
kiln
temperature
zone
differential
axially spaced
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US33811A
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English (en)
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Hugh S Drewry
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Allis Chalmers Corp
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Allis Chalmers Corp
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Assigned to WOODS KATHLEEN D., AS TRUSTEE, CONNECTICUT NATIONAL BANK THE, A NATIONAL BANKING ASSOCIATION AS TRUSTEE reassignment WOODS KATHLEEN D., AS TRUSTEE SECURITY INTEREST (SEE DOCUMENT FOR DETAILS). Assignors: ALLIS-CHALMERS CORPORATION A DE CORP.
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    • 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
    • F27B7/00—Rotary-drum furnaces, i.e. horizontal or slightly inclined
    • F27B7/20—Details, accessories, or equipment peculiar to rotary-drum furnaces
    • F27B7/42—Arrangement of controlling, monitoring, alarm or like devices

Definitions

  • ABSTRACT An apparatus for and method of controlling the operation of a cement kiln or the like in accordance with which means are provided for determining the temperature at two axially spaced locations within the calcining zone of the kiln, determining the difierential between the temperatures measured at the two axially spaced locations as an indication of whether or not the burning zone of the kiln is located at a desired axial location within the kiln, and making proper control adjustment or adjustments to the kiln to maintain substantially constant the predetermined differential between the two measured temperatures, whereby to maintain the burning zone at the proper axial location within the kiln.
  • a typical cement manufacturing installation for example, comprises an inclined rotary kiln having its lower discharge end enclosed within a firing hood.
  • a heat source or kiln burner extending through the firing hood, utilizing fuel and primary combustion air, fires the kiln from the discharge end of the kiln.
  • a clinker cooler conveyor having a perforated grate and a wind box beneath the grate extends underneath the firing hood so that its receiving end is below the discharge end ofthe kiln.
  • a finely ground mixture comprising a natural carrier of CaCO such as limestone, natural carriers of SiO and A1 such as clay or shale, and Fe O in the form of hematite or mill scale, is introduced in the form of a dry raw mix or a wet slurry into the elevated end of the kiln and due to the kilns rotation and inclination is transported toward the lower discharge end. Flame from the kiln burner is introduced into the discharge end of the kiln and this flame and its hot combustion byproducts are drawn through the kiln countercurrent to the flow of the charge therein, heating the charge in the process. As the charge progresses, its temperature is first raised to a level which drives off moisture.
  • CaCO such as limestone
  • SiO and A1 such as clay or shale
  • Fe O in the form of hematite or mill scale
  • the heating zone in which moisture is driven off from the mixture might extend, for example, for approximately 250 feet from the feed end in the direction of the discharge end; the calcining zone might extend for an additional 75 feet from the termination of the heating zone to the beginning of the burning zone; and the burning zone might extend for the last 75 feet of the length of the kiln from the end of the calcining zone to the discharge end of the kiln.
  • the values just given are only examples of the lengths of the various zones in a typical kiln.
  • the locations and lengths of the burning zone, the calcining zone, and the heating zone remain fixed for optimum operation of the given kiln.
  • the 75 foot length burning zone should remain fixed in the given kiln, assuming the kiln end product and fuel used remain unchanged.
  • the length of the burning zone particularly to change from its optimum length and position with resulting reduction in the efficiency of operation of the kiln.
  • an apparatus for and method of controlling the operation of a cement'kiln or the like in accordance with which means are provided for determining the temperature at two axially spaced locations within the calcining zone of the kiln, determining the differential between the temperatures measured at the two axially spaced locations as an indication of whether or not the burning zone of the kiln-is located at a desired axial location within the kiln, and making proper control adjustment or adjustments to the kiln to maintain substantially constant the predetermined differential between the two measured temperatures, whereby to maintain the burning zone at the proper axial location within the kiln.
  • FIG. 1 is a view in longitudinal elevation of a rotary kiln embodying the apparatus of the invention
  • FIG. 2 is a diagrammatic representation of the various zones within the kiln.
  • FIG. 3 is a graph of the under the load temperature of the cement mixture in the kiln versus kiln length.
  • FIG. I there is shown a rotary kiln generally indicated at [0 com prising a cylindrical kiln shell 12.
  • the kiln 10 is supported for rotation on its foundation 14 which is so constructedas to impart a slight downward inclination to the kiln from the feed end to the discharge end of the kiln.
  • Rollers 16 mounted on foundation 14 cooperatively engage riding rings 18 mounted on the kiln shell 12 in any well known manner for rotation of the shell about the longitudinal axis of the kiln.
  • Appropriate driving means may actuate a bevel gear 20 fixed to shaft 22 which carries a pinion 24 in intermeshing coacting engagement with ring gear 26 carried by kiln shell [2 for revolving the kiln.
  • the lower end of the kiln is associated with a firing system 28 which may be either a coal, gas-homing or other suitable type for furnishing hot gases.
  • the material to be heated in the kiln is supplied to the feed end of the kiln by means of a chute or hopper 32. As indicated in FIG.
  • the heating zone of the kiln extends for a predetermined distance such as 250 feet from the feed end of the kiln; the calcining zone in the given kiln may extend for the next 75 feet proceeding toward the discharge end; while the burning zone may extend for 75 feet from the end of the calcining zone to the discharge end of the kiln.
  • a predetermined distance such as 250 feet from the feed end of the kiln
  • the calcining zone in the given kiln may extend for the next 75 feet proceeding toward the discharge end
  • the burning zone may extend for 75 feet from the end of the calcining zone to the discharge end of the kiln.
  • the present invention relates to a means and method for insuring that the burning zone in a given kiln remains at its predetermined optimum length and position.
  • a pair of temperature sensing devices are positioned at two spaced points or locations along the kiln to measure a temperature differential between the two spaced points, corresponding to points A and B on the temperature curve of FIG. 3.
  • the two points A and B are so located within the calcining zone that the temperature vs. kiln length curve (FIG. 3) should have a predetermined slope between points A and B, as indicated by a predetermined temperature differential between points A and B, if the burning zone is properly located for optimum operation of the kiln.
  • Points A and B are selected so as to lie at points on the temperature curve of FIG. 3 at which an upward break in the rate of temperature climb vs.
  • the radiation pyrometers 34 and 36 may be similar to those shown in US. Pat. No. 3,345,873 issued to Otto G. Lellep on Oct. 10, 1967; or in US. Pat. No. 3,379,062 issued to Otto G. Lellep on Apr. 23, 1968; or in US. Pat. No. 3,472,497 issued to Harold D. Preszler on Oct. 14, 1969; or in US. Pat. No. 3,473,384 issued to Anthony V. Baron on Oct. 21, 1969.
  • the radiation pyrometers shown in the patents just mentioned are mounted on the outside of the kiln and receive radiation from the kiln interior through a sight tube or passage which extends through the kiln wall.
  • the two temperature sensing devices 34 and 36 are located in axially spaced locations along the calcining zone of the kiln.
  • the first radiation pyrometer device 34 may be installed, for example, at the 275 foot mark fifty feet upstream from the junction of the burning zone and calcining zone, and the second radiation pyrometer device 36 may be installed at the 285 foot mark, 40 feet upstream from the junction of the calcining zone with the burning zone.
  • the two radiation pyrometer devices 34 and 36 are spaced from each other feet lengthwise of the kiln axis, and both of the pyrometer devices 34 and 36 are located within the normal location of the calcining zone.
  • the radiation pyrometer device 34 feeds its signal to slip rings 40 and 42 mounted on the kiln; while the radiation pyrometer 36 feeds its output signal to the slip rings 44 and 46.
  • Contact brushes 48 connect slip rings 40 and 42 from radiation pyrometer 34 to the input of a suitable electrical amplifier 50.
  • contact brushes 52 connect slip rings 44 and 46 from radiation pyrometer 36 to the input of an electrical amplifier 54.
  • the slip rings 40-42 and 4446 may extend around the outer periphery of the drum only for an angle or are approximately corresponding to the arc subtended by the load in the kiln and the brushes 48 and 52 may be so positioned that they contact their corresponding slip rings only during the portion of the cycle of rotation during which the respective radiation pyrometers 34 and 36 are passing under the loa in the kiln.
  • the temperature signals transmitted to the amplifiers 50 and 54 will be readings of the under the load temperature at each of the respective locations A and B, which is the best criterion of material temperature in the kiln at these respective locations.
  • the electrical output signals from the amplifiers 50 and 54 are fed into the input of a signal subtracting device or differential amplifier 56 which provides an electrical output signal indicative of the differential between the two temperaferential amplifier 56 are also well known and commercially available.
  • the signal from the differential device 56 is fed to any suitable control device 58. If the firing zone of the kiln is properly located at its optimum position in the kiln, a predetermined temperature differential signal will be produced by the subtracting or differential device 56, and if this signal is at the proper predetermined value no adjustments to the kiln operation will be made.
  • Such adjustments may include, for example, any one of or combination of the following control adjustments of kiln operating variables: (1) a change in the feed rate to the kiln; (2) a change in the rate of kiln rotation; (3) a change in the fuel rate to the burner or firing means which supplies heat to the kiln; (4) a change in the axial position of the burner or firing means; or (5) a change in the draft through thekiln.
  • a rotary kiln for processing cement or the like said kiln including therein a heating zone, a calcining zone, and a burning zone, each of said zones having a predetermined location in said kiln corresponding to optimum operation of said kiln, temperature sensing means for sensing the temperature in said kiln at two axially spaced locations in the calcining zone of said kiln whose temperature differential is indicative of the location of the burning zone in said kiln; said two axially spaced locations being so positioned as to lie in a region of said calcining zone at which an upward break in the rate of temperature climb vs.
  • a differential measuring means means connecting said temperature sensing means to said differential measuring means whereby to provide an output signal from said differential measuring means which is a function of the temperature differential between said two axially spaced locations, control means for controlling the operation of said kiln in response to the output signal of said differential measuring means, and means connecting the output signal of said differential measuring means to said control means whereby to control the location of said burning zone.
  • each temperature sensing device is a radiation pyrometer.
  • a method of controlling cement kiln operation comprising the steps of determining the temperature at two axially spaced locations in the kiln, determining the temperature differential between said two locations as indicative of whether or not the burning zone is located at a desired optimum axial location within the kiln, and controlling at least one kiln operating variable to maintain substantially constant a temperature differential between said two locations corresponding to the location of the burning zone at said desired optimum location.

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  • Engineering & Computer Science (AREA)
  • Mechanical Engineering (AREA)
  • General Engineering & Computer Science (AREA)
  • Muffle Furnaces And Rotary Kilns (AREA)
  • Tunnel Furnaces (AREA)
  • Furnace Details (AREA)
US33811A 1970-05-01 1970-05-01 Apparatus for and method of controlling rotary kiln operation Expired - Lifetime US3647195A (en)

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US3381170A 1970-05-01 1970-05-01

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US3647195A true US3647195A (en) 1972-03-07

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US (1) US3647195A (de)
BR (1) BR7102626D0 (de)
CA (1) CA920689A (de)
DE (1) DE2121400C3 (de)
FR (1) FR2091033A5 (de)
ZA (1) ZA712712B (de)

Cited By (5)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US3805010A (en) * 1972-01-14 1974-04-16 Elphiac Sa Installation of heating by induction
US3888621A (en) * 1974-04-12 1975-06-10 Alcan Res & Dev Monitoring and controlling kiln operation in calcination of coke
FR2527588A1 (fr) * 1982-05-28 1983-12-02 Kloeckner Humboldt Deutz Ag Procede et dispositif pour la regulation de l'operation de cuisson dans une installation de cuisson du ciment
US4759033A (en) * 1987-07-01 1988-07-19 Weyerhaeuser Company Temperature measurement of hot mineral product by induced fluorescence
US5523957A (en) * 1993-07-15 1996-06-04 Alcan International Limited Process for controlling rotary calcining kilns, and control system therefor

Families Citing this family (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
CN108072282B (zh) * 2016-11-07 2019-10-18 南京梅山冶金发展有限公司 一种环形套筒窑煅烧自动控制方法

Citations (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US2998195A (en) * 1957-02-11 1961-08-29 Midland Ross Corp Multiple zone furnace control system
US3228670A (en) * 1963-01-23 1966-01-11 R N Corp Methods and apparatus for ore reduction and processing of other chemically reactive aggregates

Patent Citations (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US2998195A (en) * 1957-02-11 1961-08-29 Midland Ross Corp Multiple zone furnace control system
US3228670A (en) * 1963-01-23 1966-01-11 R N Corp Methods and apparatus for ore reduction and processing of other chemically reactive aggregates

Cited By (6)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US3805010A (en) * 1972-01-14 1974-04-16 Elphiac Sa Installation of heating by induction
US3888621A (en) * 1974-04-12 1975-06-10 Alcan Res & Dev Monitoring and controlling kiln operation in calcination of coke
FR2527588A1 (fr) * 1982-05-28 1983-12-02 Kloeckner Humboldt Deutz Ag Procede et dispositif pour la regulation de l'operation de cuisson dans une installation de cuisson du ciment
US4498930A (en) * 1982-05-28 1985-02-12 Klockner-Humboldt-Deutz Ag Method and device for regulating the burning process of a cement burning system
US4759033A (en) * 1987-07-01 1988-07-19 Weyerhaeuser Company Temperature measurement of hot mineral product by induced fluorescence
US5523957A (en) * 1993-07-15 1996-06-04 Alcan International Limited Process for controlling rotary calcining kilns, and control system therefor

Also Published As

Publication number Publication date
DE2121400C3 (de) 1975-06-12
CA920689A (en) 1973-02-06
DE2121400B2 (de) 1973-10-11
DE2121400A1 (de) 1971-11-18
ZA712712B (en) 1972-12-27
BR7102626D0 (pt) 1973-04-10
FR2091033A5 (de) 1972-01-14

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Owner name: WOODS KATHLEEN D., AS TRUSTEE

Free format text: SECURITY INTEREST;ASSIGNOR:ALLIS-CHALMERS CORPORATION A DE CORP.;REEL/FRAME:004149/0001

Effective date: 19830329

Owner name: CONNECTICUT NATIONAL BANK THE, A NATIONAL BANKING

Free format text: SECURITY INTEREST;ASSIGNOR:ALLIS-CHALMERS CORPORATION A DE CORP.;REEL/FRAME:004149/0001

Effective date: 19830329