US3369748A - Combustion control system - Google Patents

Combustion control system Download PDF

Info

Publication number
US3369748A
US3369748A US537786A US53778666A US3369748A US 3369748 A US3369748 A US 3369748A US 537786 A US537786 A US 537786A US 53778666 A US53778666 A US 53778666A US 3369748 A US3369748 A US 3369748A
Authority
US
United States
Prior art keywords
air
regulating
oil
signal
excess
Prior art date
Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
Expired - Lifetime
Application number
US537786A
Other languages
English (en)
Inventor
Livois Guy M Baudelet De
Current Assignee (The listed assignees may be inaccurate. Google has not performed a legal analysis and makes no representation or warranty as to the accuracy of the list.)
Controle Bailey SA
Original Assignee
Controle Bailey SA
Priority date (The priority date 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 date listed.)
Filing date
Publication date
Application filed by Controle Bailey SA filed Critical Controle Bailey SA
Application granted granted Critical
Publication of US3369748A publication Critical patent/US3369748A/en
Anticipated expiration legal-status Critical
Expired - Lifetime legal-status Critical Current

Links

Images

Classifications

    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F23—COMBUSTION APPARATUS; COMBUSTION PROCESSES
    • F23N—REGULATING OR CONTROLLING COMBUSTION
    • F23N5/00—Systems for controlling combustion
    • F23N5/003—Systems for controlling combustion using detectors sensitive to combustion gas properties
    • F23N5/006—Systems for controlling combustion using detectors sensitive to combustion gas properties the detector being sensitive to oxygen
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F23—COMBUSTION APPARATUS; COMBUSTION PROCESSES
    • F23N—REGULATING OR CONTROLLING COMBUSTION
    • F23N2235/00—Valves, nozzles or pumps
    • F23N2235/02—Air or combustion gas valves or dampers
    • F23N2235/06—Air or combustion gas valves or dampers at the air intake

Definitions

  • ABSTRACT OF THE DISCLOSURE A combustion control system in which air flow is in ratio to fuel flow but readjusted from the larger of two signals, one of which is proportional to the oxygen content in the products of combustion and the other of which is proportional to the opacity of the products of combustion.
  • the present invention relates to a regulating chain for the combustion of fuel oil with a very slight excess of air, or more precisely to a chain for regulating the excess of air used for the combustion of a heating fuel-oil with a view to maintaining this excess of air at a strict minimum.
  • the relatively high sulphur content of heavy industrial heating fuel oils is the source of difliculties resulting essentially from the corrosion suffered by the walls of heat exchangers because when these are sufliciently cold for the water vapor of combustion to condense thereon, the water thus formed dissolves the sulphuric anhydride S0 present, producing incipient sulphuric acid.
  • a first well-known solution consists in measuring the content of residual oxygen in the flue gases and in correcting the ratio of the supplies of air and of fuel oil in the appropriate sense as a function of said content of residual oxygen.
  • This first solution may still prove inadequate, however, because three kinds of risk may arise.
  • the devices for measuring the oxygen content may deviate slightly and, as it has already been seen, it is suflicient for this content to vary by a few thousandths for a departure from the prescribed zone in one direction or the other, either with too great an excess 3,369,748 Patented Feb. 20, 1968 of air leading to the recurrence of the corrosion which it was desired to avoid, or with too slight an excess of air causing the appearance of unburnt gases or solids residues.
  • the very precise oxygen analyzers which are necessary generally have response time constants which are ill-adapted to guide the regulation in a suitable manner in cases where the variations in load are rapid.
  • This mode of procedure has the following three advantages.
  • the measurement is very sensitive and a considerable deviation in the measuring instrument or opacimeter only corresponds to a very slight variation in the excess of air.
  • the response time of such an instrument is much shorter than that of an oxygen analyzer.
  • the average measuremeasurement of the opacity of the flue gases releasedavoids the three risks indicated above, involved in that of the oxygen content of said flue gases.
  • the present invention relates essentially to a system of regulating the excess of air used in the combustion of a heating fuel-oil with a view to maintaining this excess of air at the strict minimum absolutely necessary.
  • the chain for regulating the excess of air is such that at least one of the regulating signals consists of a measurement signal for the opacity of the flue gases liberated, which signal is supplied by an opacimeter.
  • FIG. 1 is a diagram of an oil-fired boiler
  • FIG. 2 is a diagram of a regulating chain comprising, as its main regulating signal, that which is constituted by a flue-gas opacity measurement signal;
  • FIG. 3 is a diagram of a regulating chain comprising direct correction of the normal regulating signal by means of a flue-gas opacity measurement signal;
  • FIG. 4 is a regulating diagram comprising correction of the normal regulating signal by means of a measurement signal for the residual oxyen content in the flue gasesi supplemented by a flue-gas opacity measurement signa
  • an oil-fired boiler comprises essentially an oil supply pipe 1, possibly with an oil fiowmeter 1a, an air supply pipe 2 possibly with an air tlowmeter 2a, said air being supplied by a blower 2b under the control of a servo-motor 2c regulating the blown air, then, downstream of the furnace 3, a steam outlet 4 and a flue-gas outlet 5, possibly with an oxygen analyzer 5x and, in any case, an opacimeter 5f. 7
  • the regulating chain only comprises the opacimeter 5] which controls the servo-motor 2c regulating the blown air by means of a regulating relay 6 with 3
  • the opacimeter only intervenes to correct a regulation efiected by other members.
  • the regulating chain comprises essentially the oil flowrneter 10: associated with the air flowmeter 2a.
  • a comparison relay which is an algebraic addition relay 2.
  • This comparison relay transmits a regulating signal, which may be pneumatic or electric for example, to the servomotor 20 for regulating the blown air, by means of the relay 6 with proportional and integral action PI.
  • this regulating chain in FIGS. 3 and 4 receives a correction signal which takes into consideration a flue-gas opacity measurement signal, produced by the opacimeter 5 In this manner, as soon as the opacity of the flue gases, which is slight but easily detected, deviates however slightly'from the average value selected as the index value, the conditions of comparison between the oil and air supplies are revised in the appropriate sense to achieve the final result aimed at.
  • the opacimeter 5f transmits this correction signal to the comparison relay by means of a relay 7 with a proportional and integral action PI.
  • the main correction signal reaching the comparison relay 2 does not originate from the opacimeter but from an oxygen analyzer 5x. This latter normally transmits a correction signal to a selector or comparator relay S which also receives information from the opacimeter 5 This selector or comparator relay S only retains the greater of these two input signals in order to transmit it to the adding relay 2.
  • this regulating chain is as follows. Normally, it is the oxygen analyzer 5x which ensures the final regulation of the combustion air. But if this correction signal proves too weak, either because of a deviation in the analyzer 5x or because of too long a response time therein, or for any reason, the opacimeter 5 provides a sort of relief for the oxygen analyzer so as to impose tem- 4 I v porarily, the appropriate adjustment of the excess combustion air. In this last embodiment, the opacimeter represents a sort of supplementary correcting member adapted to compensate for any failure in the main correcting member.
  • the correction action of the opacimeter and of the oxygen analyzer is represented in the form of an algebraic addition applied to the comparison relay 2; but it could advantageously assume the form of a multiplier relay connected into the signal originating either from the oil flowmeter or the air flowmeter.
  • Means for regulating the supply mixture of oil and air of an oil-fired boiler comprising means for supplying air and means for supplying oil to said boiler, means for measuring the flow of air and means for measuring the flow of oil, means for varying at least the flow of said air supplying means, an oxygen analyzer in the flue-gas outlet of said boiler giving a first signal function of the oxygen content of said flue-gas, an opacimeter in the fine-gas outlet of said boiler giving a second signal function of the opacity of said flue-gas, comparator means for selecting the larger of said first and second signals, adding means for generating a third signal function of the measured air flow and oil flow and of said selected larger signal and a proportional and integral action relay operated by said third signal and controlling said varying means.

Landscapes

  • Engineering & Computer Science (AREA)
  • Chemical & Material Sciences (AREA)
  • Combustion & Propulsion (AREA)
  • Mechanical Engineering (AREA)
  • General Engineering & Computer Science (AREA)
  • Regulation And Control Of Combustion (AREA)
US537786A 1965-08-14 1966-03-28 Combustion control system Expired - Lifetime US3369748A (en)

Applications Claiming Priority (1)

Application Number Priority Date Filing Date Title
FR28388A FR1453519A (fr) 1965-08-14 1965-08-14 Chaîne de régulation pour combustion de mazout à très faible excès d'air

Publications (1)

Publication Number Publication Date
US3369748A true US3369748A (en) 1968-02-20

Family

ID=8586670

Family Applications (1)

Application Number Title Priority Date Filing Date
US537786A Expired - Lifetime US3369748A (en) 1965-08-14 1966-03-28 Combustion control system

Country Status (3)

Country Link
US (1) US3369748A (fr)
FR (1) FR1453519A (fr)
GB (1) GB1151600A (fr)

Cited By (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US3723047A (en) * 1970-05-26 1973-03-27 Bailey Controle Control network for burning fuel oil and gases with reduced excess air
US4436506A (en) 1981-04-13 1984-03-13 Honeywell B.V. Control system for a gas heated water or air heater
US20220325471A1 (en) * 2021-03-31 2022-10-13 Seiko Epson Corporation Fabric Processing Method, Processed Fabric, Textile Printing Method, And Composition Set

Citations (5)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US2285564A (en) * 1942-06-09 Combustion control
US2407838A (en) * 1942-09-30 1946-09-17 Brown Instr Co Measuring apparatus
US2441025A (en) * 1946-02-28 1948-05-04 Gilbert & Barker Mfg Co Smoke responsive control for oil burners
US3184686A (en) * 1961-08-28 1965-05-18 Shell Oil Co Optimizing controller
US3216661A (en) * 1961-10-10 1965-11-09 George K Mckenzie Combustion control apparatus

Patent Citations (5)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US2285564A (en) * 1942-06-09 Combustion control
US2407838A (en) * 1942-09-30 1946-09-17 Brown Instr Co Measuring apparatus
US2441025A (en) * 1946-02-28 1948-05-04 Gilbert & Barker Mfg Co Smoke responsive control for oil burners
US3184686A (en) * 1961-08-28 1965-05-18 Shell Oil Co Optimizing controller
US3216661A (en) * 1961-10-10 1965-11-09 George K Mckenzie Combustion control apparatus

Cited By (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US3723047A (en) * 1970-05-26 1973-03-27 Bailey Controle Control network for burning fuel oil and gases with reduced excess air
US4436506A (en) 1981-04-13 1984-03-13 Honeywell B.V. Control system for a gas heated water or air heater
US20220325471A1 (en) * 2021-03-31 2022-10-13 Seiko Epson Corporation Fabric Processing Method, Processed Fabric, Textile Printing Method, And Composition Set

Also Published As

Publication number Publication date
FR1453519A (fr) 1966-06-03
GB1151600A (en) 1969-05-07

Similar Documents

Publication Publication Date Title
US4749122A (en) Combustion control system
US3723047A (en) Control network for burning fuel oil and gases with reduced excess air
US4318366A (en) Economizer
US3369749A (en) Low excess air operation of multipleburner residual-fuel-fired furnaces
CN103672948B (zh) 工业炉窑的燃烧控制系统及控制方法
US4235171A (en) Natural draft combustion zone optimizing method and apparatus
US8151740B2 (en) System and method for controlling the calorie content of a fuel
US3602487A (en) Blast furnace stove control
US2324821A (en) Measuring and control method and apparatus
US4505668A (en) Control of smoke emissions from a flare stack
US3288199A (en) Low exess air operation of multipleburner residual-fuel-fired furnaces
US3561895A (en) Control of fuel gas combustion properties in inspirating burners
US4278052A (en) Boiler control system
US4408569A (en) Control of a furnace
US1940355A (en) Furnace control
US3319887A (en) Multi-zone furnace temperature and atmosphere control
US3463599A (en) Combustion process for coal fired boilers
US2258719A (en) Method of operating vapor generators
US2079165A (en) Control system
US1972968A (en) Combustion contkol
JPS604724A (ja) 燃焼用酸素富化空気による燃焼方法
Sunderland Improving combustion efficiency by multivariable analysis and control
SU735869A1 (ru) Способ автоматической оптимизации процесса горени в котле
SU840586A2 (ru) Способ регулировани процесса го-РЕНи B ТОпКЕ СудОВОгО КОТлА
Innami et al. Real-time CO measurement in a coal fired boiler with a TDLS analyzer