US3334599A - Furnace for burning bulky fuels, especially refuse, and improved method for operating the aforesaid furnace - Google Patents

Furnace for burning bulky fuels, especially refuse, and improved method for operating the aforesaid furnace Download PDF

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Publication number
US3334599A
US3334599A US413755A US41375564A US3334599A US 3334599 A US3334599 A US 3334599A US 413755 A US413755 A US 413755A US 41375564 A US41375564 A US 41375564A US 3334599 A US3334599 A US 3334599A
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United States
Prior art keywords
grate
combustion
furnace
refuse
fuel
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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
US413755A
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English (en)
Inventor
Tanner Richard
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Von Roll AG
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Von Roll AG
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Publication date
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Publication of US3334599A publication Critical patent/US3334599A/en
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Classifications

    • 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
    • F23G5/02—Incineration of waste; Incinerator constructions; Details, accessories or control therefor with pretreatment
    • F23G5/04—Incineration of waste; Incinerator constructions; Details, accessories or control therefor with pretreatment drying
    • F23G5/05—Incineration of waste; Incinerator constructions; Details, accessories or control therefor with pretreatment drying using drying grates
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F23—COMBUSTION APPARATUS; COMBUSTION PROCESSES
    • F23B—METHODS OR APPARATUS FOR COMBUSTION USING ONLY SOLID FUEL
    • F23B1/00—Combustion apparatus using only lump fuel
    • 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
    • F23G5/002—Incineration of waste; Incinerator constructions; Details, accessories or control therefor characterised by their grates
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F23—COMBUSTION APPARATUS; COMBUSTION PROCESSES
    • F23B—METHODS OR APPARATUS FOR COMBUSTION USING ONLY SOLID FUEL
    • F23B2700/00—Combustion apparatus for solid fuel
    • F23B2700/012—Combustion apparatus for solid fuel with predrying in fuel supply area
    • 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
    • Y10—TECHNICAL SUBJECTS COVERED BY FORMER USPC
    • Y10S—TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
    • Y10S588/00—Hazardous or toxic waste destruction or containment
    • Y10S588/90—Apparatus

Definitions

  • the present invention relates to an improved furnace for burning on a grate bulky fuels of varying chemical and physical properties, for example domestic refuse, as well as to an improved method for operating the aforesaid furnace for carrying out the burning of such bulky fuels.
  • the uppermost layer of the fuel bed lying on the combustion grate is heated to ignition point so that combustion is initiated, the necessary oxygen being supplied by undergrate air blast. Due to the conduction and radiation of heat the burning zone spreads downwardly within the fuel bed, until the bed has been ignited over its entire depth.
  • the already-mentioned pre-drying of the fuel is effected generally on a separate predrying grate and by heat radiation from the flames in the combustion chamber and/or the red-hot, refractory walls and roof of the chamber.
  • This drying process is assisted or intensified, if appropriate, by hot gases, for example pre-heated air and/or re-cycled hot flue gases, blown from below through the pre-drying grate.
  • the pre-drying effect is often inadequate and, therefore, owing to the incomplete pre drying of the fuel, the already relatively slow speed at which the ignited zone is propagated downwardly in the bed of fuel is further decreased.
  • the ignition temperatures for certain fuels in question are in the region of 300 C. to 500 C. However, these temperatures are reached only after complete, at least local, drying since when heat acts on such fuel which is still moist the temperature does not rise much above 100 C. owing to the need to evaporate the moist contents. As a result, of course, the downward propagation of the ignition zone is hindered.
  • a primary object of the present invention is to provide an improved furnace for the burning of fuels of 3,334,599 Patented Aug. 8, 1967 the type specified initially and, more specifically, a furnace with a mechanical grate wherein the aforesaid disadvantages of the known burning techniques are obviated.
  • Another important object of the present invention relates to an improved method of burning on a grate bulky fuels of varying chemical and physical properties, such as domestic refuse for example.
  • an improved method of burning bulky fuels in a furnace which are of varying chemical and physical properties, for example domestic refuse, comprising the steps of: causing the fuel to travel as a bed on a combustion grate, igniting said bed from above, supplying to a location beneath an initial portion of said grate hot gas at a temperature at least sufficient to ignite a substantial proportion of said fuel on said initial portion, and passing said hot gas upwardly through said initial portion and through the fuel on said initial portion, to thereby ignite from below at least a substantial proportion of the fuel on said initial portion.
  • a furnace for use in carrying out the inventive method comprising a combustion chamber, a combustion grate at the bottom of said chamber, means for causing said fuel to travel as a bed on said combustion grate, and supply means which serves to supply to a location beneath an initial portion of said combustion grate hot gas at a temperature at least suflicient to ignite a substantial proportion of the fuel on said initial portion, said initial portion being formed of a material capable of withstanding said temperature.
  • secondary air may be introduced above and laterally of the fuel bed on the initial portion of the combustion grate for the purpose of burning the volatile constituents which are expelled from the fuel on the initial portion of the combustion grate.
  • some of the hot gas in the combustion chamber may be drawn downwardly by suction through the pre-drying grate and through the still moist fuel thereon in order to pre-dry the fuel.
  • the pre-heated undergrate blast not only furnishes the oxygen required for combustion but also a certain quantity of sensible heat, whereby a higher temperature is achieved in the combustion chamber and thus the combustion is assisted. Since the heat necessary for pre-heating the undergraduate blast is conventionally taken from the furnace at a location downstream of the combustion grate with reference to the flue gas stream, whether by air preheaters arranged in the flue gas stream or by partial re-cycling of the flue gas, the overall thermal efiiciency of the furnace is increased by the use of preheated undergrate blast.
  • the burning method of the furnace according to the present invention is founded on the basic consideration that the ignition and combustion efiiciency of the initial portion of the combustion grate could be increased by initiating ignition of the fuel bed from below simultaneously with and in addition to the ignition of the fuel bed from above by heat radiation from the combustion chamber.
  • the furnace is in this case an incinerator, and the fuel is assumed to be domestic refuse for example.
  • the fuel is introduced into the incinerator through a charging shaft 1 and then arrives at a regulata-ble feed device 2 which introduces the fuel into the actual combustion chamber 3 of the incinerator, the walls of which are covered in a suitable manner with refractory material.
  • a pre-drying grate 4 and a combustion grate 5 the latter being imagined as subdivided into two grate portions, namely an initial portion 5a and a final portion 5b.
  • the two grates 4 and 5, which can be of any mechanical continuousfeed type, are disposed one before" the other with an inclination in the same sense. The inclination and construction of the grates is such that conveyance of the fuel as a bed during combustion is obtained.
  • a vertical step 6 which ensures that the fuel-bed is subjected to a free-fall on passing to the combustion grate 5, and thereby is loosened-up mechanically.
  • complete burn-out of the fuel is achieved, the non-combustible ash being discharged through a shaft 7 disposed after the aforesaid final portion 51;.
  • a very hot blast consisting of air either directly preheated or mixed with re-cycled hot flue-gas, is blown through the initial grate portion 5a and the fuel bed 8b lying on it, the temperature of the blast being equal to or, if appropriate, even higher than the ignition point of a substantial proportion of the fuel on this initial grate portion 5a.
  • the volatile constituents issuing intensively from the fuel in the form of combustible gases in the region of the portion 5a, are ignited above the fuel bed 812.
  • a plurality of nozzles 11 are arranged in the two side walls 12 (of which only one is seen) of the furnace, above and laterally of the grate portion 5a, to blow secondary air into the combustion chamber 3, thereby supplying the necessary oxygen for the final combustion of the combustible gases, and also exerting an intensive whirling action on the combustible gases, so that a continuous flame forms above the aforesaid grate portion 5a in the combustion chamber 3.
  • the supporting and driving elements of the grate portion 5a which are acted upon by the hot gas stream 9, 9' and 9" are of adequately adapted design and construction, to withstand the high temperature of the hot gas stream which may be from 300 C. to 600 C., depending upon the nature of the fuel.
  • the pre-drying of the fuel is effected, on the pre-drying grate 4, on the one hand by heat radiated from the flames and from the red-hot, refractory walls and roof of the combustion chamber 3, and, on the other hand, by the fact that hot combustion gases from the combustion chamber 3 are sucked downwards through the pre-drying grate 4 and through the still moist fuel-bed 8a lying thereon, as is indicated schematically by arrows 13, 13 and 13" in the drawing, into a negative pressure chamber 16 situated therebelow.
  • a negative pressure is being maintained by connection to the suction side of at least one suction and pressure fan S arranged in a return conduit 17.
  • the extracted stream including the vapors, and indicated at 14, is conducted through the return conduit 17 into the furnace at a point 15 which is situated downstream of the combustion chamber 3 and just before the discharge flue 19. As can be seen, the point 15 is remote from the grates 4 and 5 and from the combustion process taking place on them.
  • a single fan S can be provided for drawing the combustion gases 13, 13 and 13" through the predrying grate 4 and also for returning the extracted stream to the chamber 3 at the point 15.
  • the fuel bed 8b is not only ignited from above by heat radiated from the combustion chamber 3, but at the same time from below by the formation of ignition nuceli at the underside of the fuel bed 8b. In this way, it is achieved that the fuel begins to burn not only at its uppermost surface but also at its lowermost surface. Consequently, the fuel bed 8b is ignited throuhout its entire bed thickness after only a short travel along the combustion grate 5.
  • a second result of blowing-in gas heated to a high temperature is that by the combined effects of the firing from below and of the sensible heat still contained in the hot underblast the gasification of the fuel bed 8b is being considerably increased.
  • the intensive expelling of the volatile constituents from the fuel considerably reduces the fuel volume and also effectively loosens-up the structure of the fuel bed, giving more advantageous burning conditions for the burning-out of the fuel on the grate portion 512.
  • a method of burning in a furnace domestic and industrial refuse of bulky condition and varying physical and chemical properties including the steps of:
  • step of pre-drying said single refuse layer further includes:
  • a furnace for burning domestic and industrial refuse of bulky condition and varying chemical and physical properties comprising:
  • combustion grate means within said combustion chamber means for receiving refuse thereon;
  • combustion grate means for causing all of said refuse to travel only as a single layer on said combustion grate means, said combustion grate means including an initial grate portion and a final grate portion;
  • supply means for supplying to a location beneath said initial grate portion of said combustion grate means hot gas at a temperature at least equal to the ignition point of a substantial portion of the single refuse layer disposed upon said initial grate portion;
  • said supply means further producing a flow of said hot gas upwardly through said initial grate portion of said combustion grate means and completely through said single refuse layer disposed thereon;
  • said combustion chamber means perfecting complete burning of the single refuse layer disposed upon said final portion of said combustion grate means.
  • said causing means further insuring that all of said refuse travels only as a single layer on said pre-drying grate;
  • suction means including at least a single suction and pressure fan, said suction means having a suction side connected to said negative pressure chamber and a pressure side connected to said furnace at a location remote from said pre-drying grate and combustion grate means and down-stream of said combustion chamber means with respect to the path of the flue gas stream in said furnace.

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  • Engineering & Computer Science (AREA)
  • Mechanical Engineering (AREA)
  • General Engineering & Computer Science (AREA)
  • Physics & Mathematics (AREA)
  • Chemical & Material Sciences (AREA)
  • Combustion & Propulsion (AREA)
  • Thermal Sciences (AREA)
  • Incineration Of Waste (AREA)
US413755A 1963-11-27 1964-11-25 Furnace for burning bulky fuels, especially refuse, and improved method for operating the aforesaid furnace Expired - Lifetime US3334599A (en)

Applications Claiming Priority (1)

Application Number Priority Date Filing Date Title
CH1454863A CH405577A (de) 1963-11-27 1963-11-27 Verfahren zur Verbrennung von sperrigen Brennstoffen unterschiedlicher Beschaffenheit mittels einer mechanischen Rostfeuerung sowie Rostfeuerung zur Durchführung dieses Verfahrens

Publications (1)

Publication Number Publication Date
US3334599A true US3334599A (en) 1967-08-08

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US413755A Expired - Lifetime US3334599A (en) 1963-11-27 1964-11-25 Furnace for burning bulky fuels, especially refuse, and improved method for operating the aforesaid furnace

Country Status (8)

Country Link
US (1) US3334599A (de)
AT (1) AT251167B (de)
BE (1) BE655905A (de)
CH (1) CH405577A (de)
DE (1) DE1451505A1 (de)
LU (1) LU47360A1 (de)
NL (1) NL6409536A (de)
SE (1) SE321045B (de)

Cited By (7)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US4354440A (en) * 1980-11-06 1982-10-19 Environmental Control Products, Inc. Underfire air and steam system and incinerating process for a controlled starved-air incinerator
US5044288A (en) * 1988-12-01 1991-09-03 Barlow James L Method and apparatus for the efficient combustion of a mass fuel
EP0683358A1 (de) * 1994-05-16 1995-11-22 Von Roll Ag Verfahren zur thermischen Energiegewinnung aus Abfallmaterial, insbesondere Müll
US6038988A (en) * 1995-07-20 2000-03-21 Forschungszentrum Kalsruhe Gmbh Waste incinerating method and apparatus with counter-current exhaust gas flow
US6647902B1 (en) * 2000-10-12 2003-11-18 Martin GmbH für Umwelt-und Energietechnik Process for incinerating waste products
US6655304B1 (en) 1999-05-21 2003-12-02 Barlow Projects, Inc. Mass fuel combustion system
US20090301364A1 (en) * 2006-06-07 2009-12-10 Forschungszentrum Karlsruhe Gmbh Method for improving the slag quality of grate firing systems

Citations (5)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US1531766A (en) * 1923-01-08 1925-03-31 Peter W Trimborn Garbage and refuse incinerator
US2032412A (en) * 1933-10-28 1936-03-03 John E Greenawalt Incinerating furnace
US2057681A (en) * 1931-12-21 1936-10-20 Harrington Joseph Method of drying and destroying municipal wastes
US2752869A (en) * 1952-01-21 1956-07-03 Oakland Scavenger Company Incinerator
US2811937A (en) * 1953-04-28 1957-11-05 Bouchard Ovide Combustion gas recuperator and smell and smoke consumer

Patent Citations (5)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US1531766A (en) * 1923-01-08 1925-03-31 Peter W Trimborn Garbage and refuse incinerator
US2057681A (en) * 1931-12-21 1936-10-20 Harrington Joseph Method of drying and destroying municipal wastes
US2032412A (en) * 1933-10-28 1936-03-03 John E Greenawalt Incinerating furnace
US2752869A (en) * 1952-01-21 1956-07-03 Oakland Scavenger Company Incinerator
US2811937A (en) * 1953-04-28 1957-11-05 Bouchard Ovide Combustion gas recuperator and smell and smoke consumer

Cited By (9)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US4354440A (en) * 1980-11-06 1982-10-19 Environmental Control Products, Inc. Underfire air and steam system and incinerating process for a controlled starved-air incinerator
US5044288A (en) * 1988-12-01 1991-09-03 Barlow James L Method and apparatus for the efficient combustion of a mass fuel
EP0683358A1 (de) * 1994-05-16 1995-11-22 Von Roll Ag Verfahren zur thermischen Energiegewinnung aus Abfallmaterial, insbesondere Müll
US5749309A (en) * 1994-05-16 1998-05-12 Von Roll Umwelttechnik Ag Process and apparatus for the thermal production of energy from waste material, particulary refuse
US6038988A (en) * 1995-07-20 2000-03-21 Forschungszentrum Kalsruhe Gmbh Waste incinerating method and apparatus with counter-current exhaust gas flow
US6655304B1 (en) 1999-05-21 2003-12-02 Barlow Projects, Inc. Mass fuel combustion system
US6647902B1 (en) * 2000-10-12 2003-11-18 Martin GmbH für Umwelt-und Energietechnik Process for incinerating waste products
US20090301364A1 (en) * 2006-06-07 2009-12-10 Forschungszentrum Karlsruhe Gmbh Method for improving the slag quality of grate firing systems
US8210112B2 (en) 2006-06-07 2012-07-03 Forschungszentrum Karlsruhe Gmbh Method for improving the slag quality of grate firing systems

Also Published As

Publication number Publication date
NL6409536A (de) 1965-05-28
CH405577A (de) 1966-01-15
AT251167B (de) 1966-12-27
BE655905A (de) 1965-03-16
SE321045B (de) 1970-02-23
DE1451505A1 (de) 1969-02-20
LU47360A1 (de) 1965-01-16

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