DD213042A1 - SOLID FUEL HEATED TUNNEL OVEN WITH MAXIMUM COOLING WASTE MANUFACTURING - Google Patents

Abstract

The invention relates to a solid fuel heated tunnel kiln with maximum Kuehlwaermerueckgewinnung u. a method of operating the same and. refers to the field of firing of ceramic, preferably coarse ceramic materials. The task u. the aim of the invention is to burn u. Cooling method u. to develop appropriate devices of the furnace technology in complex interaction or use that eliminates the existing defects of the prior art and the main benefits - reducing energy consumption and cleaning of the stock u. of the tunnel kiln car - can be achieved. The essence of the invention is, in particular, to avoid with the help of the maximum Kuehlwaermeabzuges heat losses and to regain and occurring Staubbelaestigung and Gesundheitsgefaehrdung to avoid when unloading the tunnel kiln car.

Description

Τ »Title of the invention

Solid fuel heated tunnel kiln with maximum cooling heat recovery ·

2. Field of the invention;

The field of application of the invention are solid fuel-heated ceramic tunnel kilns, preferably coarse ceramic furnaces with or without combustible constituents in the feedstock, in which the kiln is primarily cooled directly with air and another heat consumer preferably maintains this cooling air with low pollutant content in the low-temperature range. Cooling heat needed.

5. Characteristic of the known technical solutions

Solid fuel heated tunnel kiln with or without fraction of fuel in Einsatzgut are characterized in that the storage heat of the stocking and the kiln car is discharged after the Garbrand to the cooling air, which passes through the tunnel furnace in countercurrent and is introduced as Schieuftuft and in the form of a tumble cooling air in the oven in which it serves as combustion air in the region of the preheating and firing zone and the cooling air withdrawn from the furnace is partly used further for technological purposes, whereby solidification-related pollution limits the possibilities of use in its manner, by what amount; are.

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The cooling air is blown in as a sliding air at the open tunnel kiln exit by means of radial fans through slits on the walls and ceiling u / o "sucked in by the vacuum in the tunnel kiln or blown in with closed kiln exit with axial fans rigidly attached to the furnace door · The sliding air systems are limited in their cooling effect on the stock pile and tunnel kiln car especially at wide tunnel kiln. The air flows depending on the Strömlings cross-section s in the stocking stack preferably in the marginal nips and pelvis and cools the outer parts of the stocking stack · In the cooling zone is a post-combustion of the still contained in the ash or feedstock combustible components instead, so that a Kühlwärmeabzug for use in other technological processes is omitted because of pollution and harmful gas content of the cooling air, with a high proportion brennbarer.Bestandteile in feedstock, when a suitable consumer such _e as a iiachtrockner, which occurs no work Plata harassment and Korrosionsprobletae limited can be kept in the required extent cooling air withdrawn because in this case essentially only a harmful gas pollution occurs * A disadvantage is at v »g. Solutions that do not completely cool the trimming and tunnel kiln car because the cooling zone cooling airflow is too low and most of the blowing is unsuitable. "The high exit temperatures of the trimming and tunnel kiln cars lead to TOW both during manual and mechanical unloading Trouble. A further disadvantage of this air duct in the tunnel furnace, that to cope with the air and Rauchgastransportes through the entire tunnel kiln, a relatively high negative pressure to.,. Furnace exit set

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must be the cause of a high false air intrusion. over the entire kiln length is. It is not possible to set an optimum air excess. · The high false air infiltration results in excessively high temperature differences over the occupied height, especially in "the preheating zone".

Another disadvantage is that despite Kachverbrennung still an export of unburned fuel in the ash and in the product from the oven and the dust pollution of the environment is given by the ash in the discharge of the tunnel kiln car. The consequence of this firing technology, in addition to the disadvantages mentioned, is high energy losses of the firing process, essentially exhaust and extension losses.

In the use of gaseous and liquid fuels as energy carriers, technologies are known in which the disadvantages due to the energy carrier solid fuels either have no object (ash pollution) or are substantially avoided by the "clean" cooling air and its utilization in the main dryer. The ash pollution in the direct burning of solid fuels is sought to reduce by burning the fuel outside of the combustion channel (ZP: P 2705 783. 6 v. 6.10.77 / 12.4-, 79) or after the furnace exit a separate dust or Aschabblaskabine with cyclone arranges *

It is also known that metal and ceramic recuperators (heat exchangers) are installed in masonry furnaces with gas or oil heating, so as to dissipate a part of the cooling heat or feed as preheated combustion air in gas heating the own combustion process,

Another solution to the problems will be in the following

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Method (OS 2707510) described. Here, the tunnel kiln forms an energetically and air-technically closed system, ie. H. no cooling heat is released to other technological processes. Here are the! Boundary conditions

- All-round flow around the input material by single-layer transport on the tunnel kiln car

- Aufheiaung the feedstock by preheated air in the DC principle

- Supply of fresh air at several points in the preheating zone for temperature control

- Supply of cooling air at several points in the "preheating zone

- Air heating by the breath gases with internal Hekuperatorsystem

· Observed.

To solve the problem of temperature compensation in the heating zone in normal multilayer stocking, the method (OS 2601038) of blowing an air volume defined in terms of pressure and volume is proposed via controllable nozzles from an air duct system. The basic idea here is the realization of the injector principle, d, h, to inject a small amount at high pressure in order to transport a multiple of breath gases from the furnace roof to the furnace bottom. The small amount is for the air and heat balance. of the countercurrent b-driven tunnel kiln meaningless.

The aforementioned method will also be partially used in the new heating system fib? Tunnel kilns operated by Peinkeramik (WP 197120) «

4. Object of the invention

The aim of the invention is, by a change in the firing technology and arrangement of devices, the disadvantages mentioned in direct u./o. indirect use of solid fuels or combustible ... components to eliminate and to achieve the following advantages:

- Complete cooling of the fuel and essentially also the 'tunnel kiln car

- Complete burnout of combustible components

- Avoidance of difficult working conditions due to air pollution by ash and noxious gases outside the furnace system

- Increased fuel consumption to achieve maximum heat output for other technological purposes

- Controlling a stable and optimal firing process to increase throughput and improve product quality

- Recovery or «, avoidance of heat loss

- Possibilities for the production of the perfect Wärnieverbundes between firing and drying process

- Use of partially inferior or waste fuels and saving of high quality fuels in separate heat generators

- Drastic reduction of energy consumption for drying and firing and thus the reference energy of operation »

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5 "Presentation of the essence of the invention;

The invention has for its object to develop and use combustion and cooling methods and corresponding devices of the furnace technology in the complex interaction so that the causes of the identified deficiencies in direct and indirect use of solid fuels eliminated or restricted and mentioned in the objective Advantages to be achieved * In particular, the maximum cooling heat extraction by using the storage heat of the goods and the tunnel kiln cars to increase the thermal efficiency lead and thus reduce the reference energy consumption for the production of ceramic products and the dust nuisance / health hazard occurring in connection with the discharge of the tunnel kiln car avoid.

According to the invention, the object is achieved as follows: The separation of the cooling awning from the preheating and firing zone is achieved by an air curtain and the air-technical elements which act on the fixation of the maximum pressure in the combustion channel (flue gas outlet, cooling air injection and exhaust). In the main cooling zone, cooling air is injected by means of low-pressure fans and distributed over the entire cooling zone over the ceiling-side according to the requirements of the goods to be cooled. Extractor hoods removed »By using cooling air primarily by low-temperature consumers, a large amount of air can flow through the furnace or stocking and thus achieve further cooling.» The low-pressure fans, the hoods on the ceiling The hoods arranged over the length of the cooling zone should be adjusted accordingly »That the deposited ashes are not or only slightly removed. The residual cooling of the material to be removed as well as the required and

Ash removal was carried out in an intensive cooling zone pushed off from the main cooling zone .

The intensive cooling zone consists of open circulating systems with fresh air supply and adequate partial flow discharge, settling chambers and a connecting line to the combustion air system. The air is introduced via lateral and ceiling-side injection openings into the burned areas of the relieved zone, which is tightly closed and achieved by the oven exit gate a residual cooling of the stocking and the tunnel kiln car, whereby the kiln and the tunnel kiln car plateau is largely freed from the ash · The ash-laden air is drawn off laterally through wall openings and brought into Absetzζkammern equipped with baffle plates in which takes place a coarse dust separation. The system is fed with a fresh air stream and an adequate raw air stream is withdrawn, either fed directly to the combustion siuftanlage depending on the type of product as raw air or fed via a Peinabscheidung in the cooling air.

According to the type of carriage thrust, the furnace exit gate may also be formed as a box which is closed to the outside and inwardly open and in which movable, high pressure horizontally blowing axial fans are provided which circulate the last stocker stack with air, thereby cooling and ash blow out. The arranged in the main cooling zone cooling air outlets and the Heißluftabsaugung open into a Kühlluftsanioielleitung, which can be replaced if necessary by one or two oversized cooling air collection channels, in which the air velocity greatly reduced, the channels with ash squeegee, exhaust devices and baffles after the cooling air supply, and a cleaning device are to be provided, which have a further reduction of the cooling air pollution result.

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The cooling air manifold connects to a mixing box and the fan of the cooling air system. With the separation of the cooling zone omitted sliding air for the combustion zone is supplemented by a combustion air system for the direct burners and for the fuel contained in the feedstock. Combustion air is metered in at each combustion point and the pressure in the combustion channel is optimized. The vacuum systems within the space or below the combustion channel have several functions, i. H. On the one hand, the cooling systems for the ceiling elements, rails and tunnel kiln cars and on the other hand, the EaIschlufteinbruch should be reduced and thereby the required negative pressure in the combustion channel to be lowered »The with the Elaschluftanteilen in the exhaust heat dissipated heat losses are lowered and thereby a substantial compensation of the previously with the sliding air into the combustion zone The cooling air system and the sub-systems are complementary in their effect, so that the gas flow rate in the combustion and preheating zone is optimized. · Preheated raw air from the intensive cooling zone is primarily used as combustion air. Via a connecting line, this is fed to the combustion air vaporizer and via the branch lines to the ceiling or wall side combustion openings.

The structure of the negative pressure under the 'tunnel kiln car in the approach of the pressure curve in the combustion channel is generated by a flow of gas in the combustion channel rectified artificial flow, in which a gap to be created by pulling a false ceiling with flexible sealing element to the tunnel kiln car and sand channel as the upper boundary of the access channel Air is sucked, the cooling zone area to the oven inlet. The extraction of air from the gap takes place on

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Start the preheating zone through one or more openings on both sides in the furnace wall by means of suction hoods via mixing box, manifold and connection to the cooling air system. The openings in the preheating and firing zone that are not required for the extraction must be closed. Likewise, the entrances to the access channel are provided with doors. With corresponding openings of the access channel to the outside in the cooling zone area incl. Ofenausfahrt a forced air flow from the cooling zone is guaranteed to the Absaugöf-fnungen. The negative pressure in the Qfendeckenzwraum in approaching the pressure prevailing in the combustion channel vacuum is also achieved by the rectified withdrawal of the ceiling cooling with the flue gas outlet and connected via exhaust hood, mixing box and manifold the cooling air system.

6th embodiment

The invention will be explained below using an exemplary embodiment.

 The accompanying drawings show:

FIG. 1: top view of a tunnel kiln FIG. 2: top view of the intensive cooling FIG. 1 : cross section of the intensive cooling zone FIG. 4: cross section of the main cooling zone FIG. 3 ' technological diagram

The solid fuel-heated tunnel kiln consists of a preheating, firing and cooling zone and is used for firing predominantly coarse-grained products with or without a proportion of fuel in the feedstock. "In the area of the preheater 7 one below the tunnel kiln

27 an intermediate ceiling 29 retracted, whereby an open to the combustion and cooling zone gap 28 is created, which is closed in the oven inlet by a flexible sealing member 25. In this gap 28, a rectified artificial flow is generated by the Schianenkühlluft 52 and thus a negative pressure similar to that of the combustion channel * This makes it necessary to close all openings to the access channel 30 · The rail cooling air is in the furnace exit immediately before the sealing element 25th preferably discharged to both sides of the furnace by means of suction hoods 1 and a drilling line to the mixing boxes 2 «The ceiling cooling 3, with the furnace roof 31 is a pressure equalization to the combustion channel 26 is generated via the Srischlufteinspeisung 7, the required air, which then heats the The desired reduction of the negative pressure in the combustion channel 26 is by limiting its effect on the preheating and firing zone, d, h. Displacement of the zero point from the kiln exit to the end of the firing zone, separation of the cooling zone and thus reduction of the total negative pressure in the tunnel kiln and reduction of the gas flow through the preheating and firing zone, thus reducing the gas velocities and the flow resistance «The reduction of the gas flow rate continues a metered combustion air injection and, if necessary, by an additional combustion air injection 50 in the preheating and firing zone, where it is needed, and the reduction of the bottle air intake · The puffed gas is discharged through Abhaust gas extraction system 4-7 * The combustion air is piped directly through the holes 5 of Furnace roof is inserted in the combustion channel

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added in such an amount that a complete combustion of the abandoned fuel and the burning. Baren constituents of the feed takes place and thus an afterburning in the cooling zone area or a discharge of unburned components in the ashes is avoided.

Immediately after the firing zone, an air nozzle system 8 is arranged in the cooling zone on the ceiling side, which separates the preheating and firing zones from the cooling zone by means of an air curtain and effects a rapid cooling of the coating.

After this air nozzle system 8 a Keißluftabsaugung 9 is also arranged on the ceiling side, which subtracts high-temperature cooling air with the addition of fresh air and dissipates the Kühlluftsammelieitung 18.

Furthermore sind.der cooling zone, in the rear region of a slider 41 is arranged, whereby it is separated into a main · 16 and intensive cooling zone 15 ceiling side arranged a sufficient number of Auszieshshauben 6, with which the cooling air withdrawn from the tunnel kiln and via leads in the Kühlluftsammelieitung 18 is performed. The entire cooling air is introduced once through the air nozzle system 8 and the main portion via the in the main cooling zone 16 preferably arranged on the ceiling side cooling air injection 12 in the 'tunnel kiln. The Kühlluftsammelitung 18, which can be provided on demand for further reduction of .Daubbelastung in the cooling air with baffles 24-, respectively after the cooling air supply and Aschesaaüiel- 2p and withdrawal device en 22, and a cleaning device 21, is led to the mixing box 10, a Connecting line sum '-Tischkasten 2 has * The cooling air of the main cooling zone 16, the rail cooling air 51 and ceiling cooling air 52 via the fan 11

removed from the tunnel oven and the consumer, preferably a dryer 48 supplied.

In the intensive cooling zone 15 "which is separated by the slide 41 from the main cooling zone and closed at the furnace end by a tightly closing furnace door 46, a large amount of air at low pressure at defined time intervals is optionally provided laterally and on the ceiling side between the fuel lanes of the last Stuffing stacks 19. The lateral air injection takes place via nozzle-shaped openings in the furnace side wall, which is arranged directly above the plateau of the tunnel kiln car 27, the fan 32 downstream Luftstromumlenkklappe 39 is such that it closes the ceiling-side air supply line 40 and the entire Air in the side air supply line 42 leads «After a defined time interval dia Luftstromumlenkklappe 39 is switched, thus closing the side air supply line 42 and the air flow flows through the ceiling-side air supply line 40 in a Deckenseiti g arranged louver 34 with injection openings 35 lind flows around or flows through the stocking. The air introduced laterally and on the ceiling serves to cool the trimming and the tunnel kiln car, the air picking up the ashes in the fuel lanes on the Tunnelcfenwagenplateau as well as in and on the stocking and is removed via openings 33 mounted in the furnace wall, so that in the downstream settling chamber 13 "which is provided with baffles 20, a coarse separation of the ash takes place. By discharging the air via the return line 36 to the fan 32 an open ümwälzsystem is created, which is provided with a defined fresh air supply 33 and a discharge of an adequate partial air flow, the .je Art

the product via a connecting line 14 and fan 44 as unfiltered air directly to the incinerator 4, or via dedusting system for PeinabScheidung 49 as Eeinluft the mixing box 10 and thus the dryer 48 is supplied.

The ± n the settling chamber 13 precipitated ash is supplied via suction 43 of the pneumatic dust extraction plant 45 · The Ofentor 46 may also be formed as a box with corresponding tunnel kiln car thrust, which is open and closed to the outside to the inside and in the movable axial fans 1? are arranged, which blow the last stocking stack horizontally with high pressure and thus also'Abkühlung and achieve ash removal of the stocking.

Claims (6)

7 »Claim for invention 1. Solid fuel heated tunnel kiln, consisting of preheating zone, combustion zone and cooling zone for firing ceramic products with or without combustible constituents in the feedstock characterized in that in the preheating zone below the tunnel kiln car to the combustion and cooling zone open space (28) by the arrangement of a airtight intermediate ceiling (29) is provided which is provided in the 3ereich the furnace entrance with a flexible sealing element (25) and preferably on both sides in the region of the inlet zone suction hoods (1) are arranged, which are connected by a pipe to a mixing box (2) in addition, the pipeline from the pool cooling (3) receives and is connected to a further mixing box (10) via a pipe which receives the cooling air manifold (18) and via an outlet line to the fan (11) that the cooling zone adjoining the combustion zone is separated by a slide (41) into a main cooling zone (16) and an intensive cooling zone (15) and ends with a relatively tight closing furnace gate (46) and at the beginning the main cooling zone (16) preferably ceiling side air nozzle rows (8), and at the end fans (12) and over the area of the main cooling zone (16) hoods (16) are preferably arranged on the ceiling side, and an intensive cooling zone (15)> the essential components of open ümv / älzsystenie for the ash-laden cooling air and from set ζ chambers (13) Jsit baffles ( 20), and a connecting line (14) to the combustion air system (4), and to complete the system for maximum cooling heat recovery. 2. Solid fuel heated tunnel kiln according to item 1, characterized in that in the preheating and combustion zone additional Verbrennungsiuftdüsen (50) are arranged. 3 · solid fuel heated tunnel kiln according to item 1, characterized in that in the intensive cooling zone (15) ceiling (35) and lateral Sinblasöffnungen (37) j and lateral exhaust ports (33) j and an open Uuiwäl ζ system consisting of Bückführleitung (36) with fresh air supply ( 33), fan (32) with adjoining Luftstromumlenkklappe (39) »and" ceiling-side (40) and lateral air supply lines (42), and Absetzkammern (13) sit baffles (20) and Verbinaungsleitung (14) to the combustion air system (4) are arranged. 4. Solid fuel heated tunnel kiln according to item 1 characterized 'characterized in that the cooling air manifold (18) is dimensioned so that the entrained ash partially sedimented and removed with appropriate Asehesamme1- (23), trigger (22) and cleaning devices (21) from the cooling air system can be. 5 * Solid fuel-heated tunnel kiln according to item 1, characterized in that preferably movable, horizontally-blowing axial fans (1 ') are arranged in the relatively tight-fitting furnace exit gate (46). « Method for operating a solid fuel-heated tunnel kiln characterized in that a pressure profile similar to that in the combustion channel (26) is built up in the intermediate space (28) below the tunnel kiln carriage (27) and in the furnace roof (31) and in that the maximum cooling heat recovery through, the separation of the cooling zone from the combustion zone and the cooling of the rails and the undercarriage parts and the furnace roof, wherein an air curtain between the combustion and cooling zone is constructed and the supplied cooling air is completely withdrawn from the cooling zone and the required combustion air in the preheating and Combustion zone is supplied and in the intensive cooling zone the ash removal and Hestabkühlung of the kiln and the tunnel kiln car takes place by an air circulation, wherein a coarse separation of Ümwälzluftstromes in settling chambers (13) with baffles (20) and in this recirculation air flow a fresh air and an "adequate partial air flow to a coarse deaerated separation is dissipated and preferably the combustion air system (4) is supplied and the extracted cooling air from the Hauptkühlζοhe (16) mixed with the partial air streams of the rail and ceiling cooling are supplied to other consumers « For this 5 pages drawings