EP0232342A1 - Procede de fonctionnement d'un four tunnel, et four tunnel - Google Patents

Procede de fonctionnement d'un four tunnel, et four tunnel

Info

Publication number
EP0232342A1
EP0232342A1 EP19860904803 EP86904803A EP0232342A1 EP 0232342 A1 EP0232342 A1 EP 0232342A1 EP 19860904803 EP19860904803 EP 19860904803 EP 86904803 A EP86904803 A EP 86904803A EP 0232342 A1 EP0232342 A1 EP 0232342A1
Authority
EP
European Patent Office
Prior art keywords
gas
tunnel furnace
zone
furnace
heating
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.)
Withdrawn
Application number
EP19860904803
Other languages
German (de)
English (en)
Inventor
Wilhelm Morgante
Andreas Hässler
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.)
Individual
Original Assignee
Individual
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
Priority claimed from DE19853525771 external-priority patent/DE3525771A1/de
Priority claimed from DE19863604219 external-priority patent/DE3604219A1/de
Application filed by Individual filed Critical Individual
Publication of EP0232342A1 publication Critical patent/EP0232342A1/fr
Withdrawn legal-status Critical Current

Links

Classifications

    • 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
    • F27B9/00—Furnaces through which the charge is moved mechanically, e.g. of tunnel type; Similar furnaces in which the charge moves by gravity
    • F27B9/30—Details, accessories, or equipment peculiar to furnaces of these types
    • F27B9/3005—Details, accessories, or equipment peculiar to furnaces of these types arrangements for circulating gases

Definitions

  • the invention relates to a method for operating a tunnel kiln, in which the kiln gas is conducted in countercurrent in the cooling zone and in cocurrent in the heating zone and in which kiln gas is removed from a high temperature zone for discharge into the environment, and also kiln gas is fed from the high-temperature zone to the heating zone and a tunnel furnace for carrying out the process.
  • Firing zone removed from the tunnel kiln and fed to the heating zone.
  • This furnace gas is very rich in oxygen and the result of this is that premature combustion of sulfurized substances from the fuel-containing stock can occur in the heating zone.
  • more furnace waste heat is generated than is required for the drying process. This applies in particular if the dry heat requirement is low due to the low water content of the moldings.
  • the invention is based on the object of designing a combustion process of the type presumed to be known in such a way that an economically favorable and stable process control is possible.
  • the furnace gas supplied to the heating zone should have only a low oxygen content in order to avoid premature ignition of fuel and inadvertent excessive heating of the stock in the heating zone.
  • the method according to the invention or the tunnel furnace for carrying out this method should have at least some of the following properties: a) No or as little as possible flue gas should be present in the cooling zone. b) The combustion air required for the combustion process is intended to cross the combustion zone in countercurrent directly from the cooling unit. ⁇ ) It should not be necessary to add flue gases to the main combustion zone, cooling or rapid cooling zone. d) It should be possible to extract exhaust gas with the lowest possible excess air without gas separation problems at a temperature which is sufficiently high to oxidize or burn the pollutants. e) Even with largely self-burning trimmings, a favorably graded heating curve should be possible in order to achieve high furnace outputs.
  • a preferred embodiment of the invention aims at the exhaust gas or during the burning and drying process. To keep exhaust air volumes as low as possible. This is preferably done in that there is no reloading of the firing material between the drying process and the firing process.
  • the direct heating of the firing material in the heating zone is to be preceded by a drying process carried out in direct current.
  • two direct current processes namely direct current drying and direct current heating, are connected in series. This results in the smallest amounts of waste heat with a particularly gentle treatment of the dry material.
  • a further aim of a preferred embodiment of the invention is to distribute the low-oxygen, high-quality furnace gas originating from the high-temperature range particularly evenly and inexpensively in the heating zone.
  • the aim is to achieve a temperature distribution that is as uniform as possible in the cross sections of the heating zone.
  • This object is achieved in that the oxygen-depleted furnace gas used in the heating zone is fed in by means of movable heating gas distributors which can be raised and lowered transversely to the longitudinal axis of the tunnel furnace.
  • the lifting and lowering can be intermittent during the blowout Periods.
  • Figure 1 the schematic of a first embodiment of the
  • Tunnel furnace Figure 2 - the temperature curve of the tunnel furnace according to Figure 1
  • Figure 3 the pressure curve for the tunnel furnace according to Figure 1
  • Figure 4 - a schematic representation of another embodiment of the tunnel furnace analog
  • Figure 1 Figure 5 - the temperature curve for the tunnel kiln according to Figure 4
  • Figure 6 - a schematic representation of a tunnel kiln, which essentially only
  • FIG. 7 shows a gas flow, a temperature curve for the tunnel furnace according to FIG. 6, FIG. 8, a cross section through the heating zone with gas distribution devices,
  • firing cars 10 can be moved in the direction of arrow 11.
  • the actual tunnel furnace is preceded by a preheating chamber 6, which can also be designed as a direct current dryer.
  • the preheating chamber has a shut-off device 12 at its entrance and a shut-off device 13 for separation, compared to a heating zone 3.
  • the temperature curve 4 shown in FIG. 2 shows the temperature profile in the different areas of the tunnel furnace.
  • the temperature curve shows the temperature in the heating zone 3 rising to 800 ° C.
  • the furnace gas flow denoted by 25 is conducted in direct current to the firing material, that is to say in direct current to the kiln 10.
  • the exhaust gas is discharged through the outlet 16 by means of an exhaust gas discharge line 2 from the tunnel furnace.
  • the exhaust gas flows through a heat exchanger 5, which is used to heat an air flow 19. Further heated air originating from the cooling zone can be mixed into the air flow 19.
  • the energy in the air can be used for other purposes, for example way to operate a dryer.
  • the oxygen-rich air removed at the outlet 20 can be introduced into the heating zone 3 via the lines 21 and 22 and via the outlets 22a if necessary for process control.
  • a partial stream of the exhaust gas can also be mixed into line 22 via a return line 8.
  • the gas in line 22 can be conveyed with a blower 18.
  • furnace gas While the furnace gas is passed through the entire heating zone in cocurrent, it flows through the cooling zone 26 and, viewed in the product conveying direction, up to the cooking zone 27 in countercurrent.
  • the furnace gas stream 28 is removed at an outlet 15.
  • the furnace gas withdrawn at 15 is fed to the preheating chamber by means of a blower 17 through a feed line 7.
  • the feed line 7 feeds into the preheating chamber 3 by means of outlets 7a.
  • Extraction lines 7b which have fans 23, lead from the heating zone 3 back into the feed line 7.
  • smoldering gases are transferred from the heating zone via lines 7b to line 7, which burn there with the hot gases.
  • the heating zone may have new heating gases available via additional circulation devices.
  • the furnace gas in the feed line 7 can either be heated or cooled if necessary.
  • cooled exhaust gas which is located in the return line 8 can be fed in.
  • the corresponding connection is not shown in the drawing figure 1. It is also possible, if necessary, to feed 29 additional energy via an additional firing.
  • a DC dryer or a preheating chamber is designated. .
  • a further shut-off device 14 is located at the furnace exit.
  • a tunnel kiln operated according to the described method avoids the undesirably high level Temperature rise in the area of the heating zone, as occurred in known processes with trimmings that contain a lot of fuel.
  • the DC dryer 6 ' is provided between the shut-off devices 11' and 13 '.
  • the heating zone 3 ' follows and then follows the high-temperature zone 27', to which the cooling zone 26 'is connected.
  • the moist air stream 110 passes from the dryer 6 'to the heat exchanger 5' and from there the heated moist air stream 111 reaches the dryer 6 '.
  • 114 is the cooled exhaust gas flow and 113 the exhaust air flow from the dryer 6 ', which is fed to any device 107, in which the dryer waste heat is utilized.
  • the basic process scheme corresponds to the scheme of FIGS. 1 and 4.
  • the corresponding reference numerals are provided with double dashes, so that a more detailed description of the process in connection with FIGS. 6 and 7 is unnecessary.
  • the furnace gas is fed via the feed line 7 "and its outlets 7a" to the front area 6a "of the heating zone 6".
  • the hot gas is introduced into the heating zone via hot gas distributors 209, which can be channel-shaped and can be raised and lowered in the combustion channel. So they are arranged within transverse heating slots.
  • the gas stream 25 " is led in cocurrent to the kiln car, likewise its continuation 219 'to the outlet 15'.
  • the furnace gas stream 28 ' is led to the outlet 15" in counterflow to the kiln conveying direction 11 ".
  • FIG. 8 shows the arrangement and function of the hot gas distributors 209 with a combustion channel cross section.
  • the hot gas flow is introduced via blowers 206 into shafts 211 which are provided in the furnace side wall 212.
  • Via side Foxes 213 introduce the hot gas into the hot gas distributor 209. There it exits laterally and / or downwards via outlet slots 214.
  • a high can be achieved by lifting and lowering movements
  • the blow-out temperature can be reduced by adding furnace gas between the transfer line and the fox 213. Due to the low blow-out speeds, the drive power for the fans is relatively low and all line parts are only exposed to low pressure.
  • the hot gas distributors 209 can be designed, for example, as hoods which are open at the bottom or as cover plates, in order in this way to always form a sole transverse channel carrying hot gas.
  • hot gas is fed in via a furnace inlet valve 216.
  • the furnace inlet slide 216 has in the lower area Hot gas outlet openings 217, by means of which the firing stack 218 entering the furnace in each case can immediately be heated particularly intensively.

Landscapes

  • Engineering & Computer Science (AREA)
  • Mechanical Engineering (AREA)
  • General Engineering & Computer Science (AREA)
  • Waste-Gas Treatment And Other Accessory Devices For Furnaces (AREA)
  • Tunnel Furnaces (AREA)

Abstract

Dans le procédé ci-décrit, le gaz du four dans la zone de refroidissement est amené au produit combustible à contre-courant et dans la zone de réchauffage, à courant parallèle. Le gaz brulé est évacué dans l'environnement depuis une zone du four présentant une température élevée. D'autre part, du gaz du four est prélevé de la zone à haute température et introduit dans la zone de réchauffage. Le prélèvement du gaz de four destiné à alimenter la zone de réchauffage s'effectue dans la direction du produit en amont d'acheminement ou dans la zone principale de combustion. Le gaz du four traverse toute la zone principale de combustion à contre-courant. Le gaz du four introduit dans la zone de réchauffage est très pauvre en oxygène.
EP19860904803 1985-07-19 1986-07-21 Procede de fonctionnement d'un four tunnel, et four tunnel Withdrawn EP0232342A1 (fr)

Applications Claiming Priority (6)

Application Number Priority Date Filing Date Title
DE19853525771 DE3525771A1 (de) 1985-07-19 1985-07-19 Tunnelofen mit schadstoffarmem abgasstrom
DE3525771 1985-07-19
DE3539495 1985-11-07
DE19853539495 DE3539495A1 (de) 1985-07-19 1985-11-07 Verfahren zum trocknen und brennen von vorzugsweise brennstoffhaltigem brenngut und/oder selbstbrennenden brennwagenbesaetzen
DE3604219 1986-02-11
DE19863604219 DE3604219A1 (de) 1986-02-11 1986-02-11 Verfahren zur stufenfoermigen sohlaufheizung in durchlaufoefen fuer keramische erzeugnisse

Publications (1)

Publication Number Publication Date
EP0232342A1 true EP0232342A1 (fr) 1987-08-19

Family

ID=27193314

Family Applications (1)

Application Number Title Priority Date Filing Date
EP19860904803 Withdrawn EP0232342A1 (fr) 1985-07-19 1986-07-21 Procede de fonctionnement d'un four tunnel, et four tunnel

Country Status (3)

Country Link
EP (1) EP0232342A1 (fr)
AU (1) AU6223086A (fr)
WO (1) WO1987000611A1 (fr)

Families Citing this family (6)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
EP0229828B1 (fr) * 1985-06-28 1991-02-27 Aluminum Company Of America Procede pour extraire des substances volatiles de la surface d'aluminium
GB8713128D0 (en) * 1987-06-04 1987-07-08 Shipley P S Tunnel kilns
JP2543565B2 (ja) * 1988-03-31 1996-10-16 日本碍子株式会社 セラミックスの焼成に用いるトンネル炉
DE19849757A1 (de) * 1998-10-28 2000-05-04 Vinz Peter Kontinuierlich betriebener Rollenherdofen mit nachgeordneter zwangskonvektiver Glühgutabkühlung
EP1842929A1 (fr) * 2006-04-06 2007-10-10 Linde Aktiengesellschaft Coffret inférieur à zéro pour le traitement intégré des métaux
PL2691720T3 (pl) * 2011-03-29 2019-08-30 Kellogg Company Piec z systemem odzyskiwania ciepła

Family Cites Families (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
FR496153A (fr) * 1919-02-03 1919-10-29 Albert Hirt Perfectionnements apportés aux fours tunnels à tirage divergeant à récupération
US1773011A (en) * 1928-05-09 1930-08-12 Harry M Robertson Kiln
DE2653118A1 (de) * 1976-11-23 1978-05-24 Haessler Andreas Verfahren zum betrieb von tunneloefen fuer keramische erzeugnisse

Non-Patent Citations (1)

* Cited by examiner, † Cited by third party
Title
See references of WO8700611A1 *

Also Published As

Publication number Publication date
WO1987000611A1 (fr) 1987-01-29
AU6223086A (en) 1987-02-10

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Inventor name: MORGANTE, WILHELM

Inventor name: HAESSLER, ANDREAS