CN114877672A - Flue gas circulation energy-saving tunnel kiln - Google Patents

Flue gas circulation energy-saving tunnel kiln Download PDF

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Publication number
CN114877672A
CN114877672A CN202210565351.1A CN202210565351A CN114877672A CN 114877672 A CN114877672 A CN 114877672A CN 202210565351 A CN202210565351 A CN 202210565351A CN 114877672 A CN114877672 A CN 114877672A
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China
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flue gas
air
kiln
communicated
outlet
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CN202210565351.1A
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Chinese (zh)
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席玉林
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Beijing Camberg Technology Co ltd
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Beijing Camberg Technology Co ltd
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Priority to CN202210565351.1A priority Critical patent/CN114877672A/en
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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
    • F27B9/00—Furnaces through which the charge is moved mechanically, e.g. of tunnel type; Similar furnaces in which the charge moves by gravity
    • F27B9/02—Furnaces through which the charge is moved mechanically, e.g. of tunnel type; Similar furnaces in which the charge moves by gravity of multiple-track type; of multiple-chamber type; Combinations of furnaces
    • F27B9/028—Multi-chamber type furnaces
    • 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
    • F27B9/12—Furnaces through which the charge is moved mechanically, e.g. of tunnel type; Similar furnaces in which the charge moves by gravity with special arrangements for preheating or cooling the charge
    • 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
    • F27B9/14—Furnaces through which the charge is moved mechanically, e.g. of tunnel type; Similar furnaces in which the charge moves by gravity characterised by the path of the charge during treatment; characterised by the means by which the charge is moved during treatment
    • F27B9/20—Furnaces through which the charge is moved mechanically, e.g. of tunnel type; Similar furnaces in which the charge moves by gravity characterised by the path of the charge during treatment; characterised by the means by which the charge is moved during treatment the charge moving in a substantially straight path tunnel furnace
    • F27B9/26—Furnaces through which the charge is moved mechanically, e.g. of tunnel type; Similar furnaces in which the charge moves by gravity characterised by the path of the charge during treatment; characterised by the means by which the charge is moved during treatment the charge moving in a substantially straight path tunnel furnace on or in trucks, sleds, or containers
    • F27B9/262—Furnaces through which the charge is moved mechanically, e.g. of tunnel type; Similar furnaces in which the charge moves by gravity characterised by the path of the charge during treatment; characterised by the means by which the charge is moved during treatment the charge moving in a substantially straight path tunnel furnace on or in trucks, sleds, or containers on or in trucks
    • 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
    • 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
    • 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
    • F27B9/40—Arrangements of controlling or monitoring devices
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F27—FURNACES; KILNS; OVENS; RETORTS
    • F27D—DETAILS OR ACCESSORIES OF FURNACES, KILNS, OVENS, OR RETORTS, IN SO FAR AS THEY ARE OF KINDS OCCURRING IN MORE THAN ONE KIND OF FURNACE
    • F27D17/00—Arrangements for using waste heat; Arrangements for using, or disposing of, waste gases
    • F27D17/004—Systems for reclaiming waste heat
    • 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
    • F27B9/12—Furnaces through which the charge is moved mechanically, e.g. of tunnel type; Similar furnaces in which the charge moves by gravity with special arrangements for preheating or cooling the charge
    • F27B2009/122—Preheating
    • 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
    • F27B9/12—Furnaces through which the charge is moved mechanically, e.g. of tunnel type; Similar furnaces in which the charge moves by gravity with special arrangements for preheating or cooling the charge
    • F27B2009/124—Cooling
    • 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
    • F27B2009/3033—Fumes circulating in the same direction as the charge
    • 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
    • F27B2009/3088—Drying arrangements
    • 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
    • Y02—TECHNOLOGIES OR APPLICATIONS FOR MITIGATION OR ADAPTATION AGAINST CLIMATE CHANGE
    • Y02P—CLIMATE CHANGE MITIGATION TECHNOLOGIES IN THE PRODUCTION OR PROCESSING OF GOODS
    • Y02P40/00—Technologies relating to the processing of minerals
    • Y02P40/60—Production of ceramic materials or ceramic elements, e.g. substitution of clay or shale by alternative raw materials, e.g. ashes

Abstract

The invention discloses a flue gas circulation energy-saving tunnel kiln, which comprises a kiln head and a kiln tail, which are sequentially arranged in the direction from the kiln head to the kiln tail: the preheating zone is positioned on the side of the kiln head closed door, and a circulating flue gas outlet is arranged on the upstream side of the preheating zone; a fresh air inlet is arranged at the downstream side of the burning zone; a cooling zone, the downstream side of which is provided with a circulating flue gas inlet; and the hot air belt is positioned on the side of the kiln tail closing door, a cold air inlet is arranged on the downstream side of the hot air belt, and a hot air outlet is arranged on the upstream side of the hot air belt. The tunnel kiln meets stricter environmental protection emission standards through a smoke circulation heat exchange technology, can be continuously fired at one time, has the characteristics of high efficiency and energy conservation, can effectively improve the product percent of pass, and realizes large-scale continuous production of the green and red tiles.

Description

Flue gas circulation energy-saving tunnel kiln
Technical Field
The invention relates to a tunnel kiln. More specifically, the invention relates to a flue gas circulation energy-saving tunnel kiln.
Background
As a continuous kiln, the tunnel kiln has the characteristics of short firing time, high yield, good product quality, good labor condition, long continuous service life and the like compared with other types of kilns, the tunnel kiln is commonly used for firing red bricks and tiles, the technology for producing the red bricks and tiles by the tunnel kiln in China is mature at present, but the ventilation in the kiln is large, the oxygen content of flue gas is generally higher than 17%, the waste gas treatment capacity is large, the environment protection cannot reach the standard easily, and the energy consumption is large.
Present tunnel cave adopts single passageway, cool off and the heat transfer with the new trend, all new trends become the flue gas after passing through the tunnel cave, directly discharge, for satisfying the heat transfer requirement, the air volume is huge, simultaneously the kiln calcines, and need not so huge air quantity, this just makes flue gas oxygen content too high, most air directly discharges, most heat is taken away to this inevitable, the flue gas handling capacity is huge simultaneously, also make the flue gas treatment facility of tunnel cave huge, also difficult the reaching environmental protection requirement when the investment increases.
When firing the blue brick, the brick tile that becomes blue after the reduction roasting, in order to prevent to oxidize again and become red, must cool off in the atmosphere of anaerobic reduction, the temperature reaches below safe temperature 300 ~ 400 ℃ in the kiln, just can contact air cooling to going out of the kiln, current tunnel cave is because oxygen air excess coefficient is very big, can't realize reducing atmosphere in the cooling zone in the kiln, can only produce red brick, and the tunnel cave of firing the blue brick tile is very rare and the structure is complicated, and current tunnel cave is because its anaerobic cooling means is limited, hardly realize the continuous production of blue brick tile.
Disclosure of Invention
The invention provides a flue gas circulation energy-saving tunnel kiln, which accords with stricter environmental protection emission standards through a flue gas circulation heat exchange technology, can be continuously fired at one time, has the characteristics of high efficiency and energy conservation, can effectively improve the product percent of pass, and realizes large-scale continuous production of green and red bricks and tiles.
To achieve these objects and other advantages in accordance with the purpose of the invention, there is provided a flue gas circulation energy-saving tunnel kiln, comprising, sequentially arranged from a front to a rear of the kiln:
the preheating zone is positioned on the side of the kiln head closed door, and a circulating flue gas outlet is arranged on the upstream side of the preheating zone;
a fresh air inlet is arranged at the downstream side of the burning zone;
a cooling zone, the downstream side of which is provided with a circulating flue gas inlet;
the hot air belt is positioned on the side of the kiln tail sealing door, a cold air inlet is arranged on the downstream side of the hot air belt, and a hot air outlet is arranged on the upstream side of the hot air belt;
the kiln is provided with a first circulating heat-insulating pipeline outside the kiln, the first circulating heat-insulating pipeline is provided with a circulating fan, an air inlet of the circulating fan is communicated with the circulating flue gas outlet, an air outlet of the circulating fan is communicated with the circulating flue gas inlet, an air outlet of the circulating fan is also communicated with a flue gas inlet of a flue gas treatment facility through a flue gas treatment pipeline, and a flue gas outlet of the flue gas treatment facility is communicated with a smoke exhaust chimney;
an air cooler is arranged outside the kiln, and an air outlet of the air cooler is communicated with the cold air inlet;
a fresh air fan is arranged outside the kiln, an air inlet of the fresh air fan is communicated with the hot air outlet, an air outlet of the fresh air fan is communicated with the fresh air inlet, and the fresh air is sprayed into the kiln to form a first air curtain;
an air curtain fan is further arranged outside the kiln, an air inlet of the air curtain fan is communicated with the hot air outlet, an air outlet of the air curtain fan is communicated with the air inlet of the air curtain and sprayed into the kiln to form a second air curtain, the upstream side of the second air curtain is the cooling zone, and the downstream side of the second air curtain is the hot air zone;
the drying chamber and the tunnel kiln are arranged in parallel, the drying chamber is provided with an air inlet and an air outlet, the air inlet of the drying fan is communicated with the hot air outlet, the air outlet of the drying fan is communicated with the air inlet of the drying chamber, the air outlet of the drying chamber is communicated with the air inlet of the dehumidifying fan, and the air outlet of the dehumidifying fan is communicated with a dehumidifying chimney;
and the air volume ratio of the drying fan to the fresh air fan is a drying coefficient and is controlled to be 2-7.
Preferably, the first circulating heat-insulating pipeline is also provided with a heat exchanger which is provided with a flue gas inlet, a flue gas outlet, a cold air inlet and a hot air outlet;
the circulating flue gas outlet is communicated with the flue gas inlet of the heat exchanger, and the air inlet of the circulating fan is communicated with the flue gas outlet of the heat exchanger;
the air outlet of the fresh air fan is communicated with the cold air inlet of the heat exchanger, and the fresh air inlet is communicated with the hot air outlet of the heat exchanger.
Preferably, the cross section of the burning zone is increased compared with the preheating zone, the cooling zone and the hot air zone, and a bypass air duct is formed at the side part or the top part of the burning zone.
Preferably, during internal combustion roasting, fresh air is air or oxygen-enriched air and is injected into the kiln through the fresh air inlet; when external combustion roasting is carried out, fresh air and fuel are mixed and then combusted to generate hot air, and the hot air is sprayed into the kiln through the fresh air inlet; when internal combustion and external combustion are mixed and roasted, the fuel is sprayed into the kiln along with fresh air from the fresh air inlet.
Preferably, movable stop doors are arranged among the preheating zone, the burning zone, the cooling zone and the hot air zone, when the kiln car travels, all the movable stop doors are opened simultaneously or sequentially after all the fans stop running, when the kiln car stops, all the movable stop doors are closed simultaneously, the preheating zone, the burning zone, the cooling zone and the hot air zone form four independent spaces, and all the fans start running;
a high-temperature flue gas inlet is also arranged at the downstream side of the preheating zone;
the fresh air inlet on the downstream side of the burning zone is replaced by a hot air inlet, and the hot flue gas outlet is also arranged on the upstream side of the burning zone;
a high-temperature flue gas outlet is also formed in the upstream side of the cooling zone;
the air curtain fan and the air curtain air inlet are omitted;
a second circulating heat-insulating pipeline is arranged outside the kiln and is respectively communicated with the high-temperature flue gas inlet and the high-temperature flue gas outlet;
the air outlet of the fresh air fan is communicated with the hot air inlet;
the flue gas inlet of the flue gas treatment facility is communicated with the hot flue gas outlet;
the oxygen content in the flue gas treatment pipeline is an oxygen index, and the control range is 0-17%;
the carbon monoxide content in the first circulation heat-insulation pipeline and the second circulation heat-insulation pipeline is a reduction index, and the control range is 0-7.5% during firing.
Preferably, the flue gas treatment pipeline is also provided with a heat exchanger which is provided with a flue gas inlet, a flue gas outlet, a cold air inlet and a hot air outlet;
the hot flue gas outlet is communicated with the flue gas inlet of the heat exchanger, and the flue gas inlet of the flue gas treatment facility is communicated with the flue gas outlet of the heat exchanger;
the air outlet of the fresh air machine is communicated with the cold air inlet of the heat exchanger, and the hot air inlet is communicated with the hot air outlet of the heat exchanger.
Preferably, the reduction index is controlled within the range of 1.0-7.5% when the black bricks are fired.
Preferably, a third circulating heat-insulating pipeline is further arranged outside the kiln, the third circulating heat-insulating pipeline is respectively communicated with the air outlet of the circulating fan and the hot air inlet, and a flow regulating valve is further arranged on the third circulating heat-insulating pipeline.
Preferably, the top and the side walls of the preheating zone and the cooling zone are provided with inward protruding strips to form a corrugated structure.
Preferably, the top of the burning zone is provided with a boiler, and a boiler calandria is in contact with flue gas of the burning zone for heat exchange.
The invention at least comprises the following beneficial effects:
the tunnel kiln meets stricter environmental protection emission standards through a smoke circulation heat exchange technology, can be continuously fired at one time, has the characteristics of high efficiency and energy conservation, can effectively improve the product percent of pass, and realizes large-scale continuous production of the green and red tiles.
The tunnel kiln is divided into 4 parts, and comprises a preheating zone, a burning zone, a cooling zone and a hot air zone, wherein the preheating zone and the cooling zone adopt circulating flue gas for heat exchange, the burning zone adopts fresh air for independent combustion, and the hot air zone adopts fresh air for cooling and provides hot air for calcination of the burning zone and drying of a drying chamber.
The invention adopts the circulating flue gas to finish heat exchange, adopts the fresh air with high oxygen content in the air to finish combustion, and can realize complete independence of the two systems, thereby meeting the flue gas heat exchange requirement of adopting reducing atmosphere in the cooling process required by the blue brick to produce the antique blue brick, and simultaneously realizing the step change of the product between red and cyan by controlling the oxygen content and the reducing atmosphere in the circulating flue gas.
Additional advantages, objects, and features of the invention will be set forth in part in the description which follows and in part will become apparent to those having ordinary skill in the art upon examination of the following or may be learned from practice of the invention.
Drawings
FIG. 1 is a schematic structural diagram of one embodiment of the present invention;
FIG. 2 is a schematic structural diagram of an embodiment of the present invention;
FIG. 3 is a schematic structural diagram of an embodiment of the present invention;
FIG. 4 is a schematic structural diagram of an embodiment of the present invention;
fig. 5 is a schematic structural diagram of an embodiment of the present invention.
Detailed Description
The present invention is further described in detail below with reference to the attached drawings so that those skilled in the art can implement the invention by referring to the description text.
It will be understood that terms such as "having," "including," and "comprising," as used herein, do not preclude the presence or addition of one or more other elements or groups thereof.
It is to be noted that the experimental methods described in the following embodiments are all conventional methods unless otherwise specified, and the reagents and materials, if not otherwise specified, are commercially available; in the description of the present invention, it should be noted that unless otherwise explicitly stated or limited, the terms "mounted," "connected," and "disposed" are to be construed broadly and can, for example, be fixedly connected, disposed, detachably connected, disposed, or integrally connected and disposed. The specific meanings of the above terms in the present invention can be understood in specific cases to those skilled in the art. The terms "lateral," "longitudinal," "upper," "lower," "front," "rear," "left," "right," "vertical," "horizontal," "top," "bottom," "inner," "outer," and the like are used in the orientation or positional relationship indicated in the drawings for convenience in describing the invention and to simplify the description, and do not indicate or imply that the device or element being referred to must have a particular orientation, be constructed and operated in a particular orientation, and thus should not be construed as limiting the invention.
As shown in fig. 1, the invention provides a flue gas circulation energy-saving tunnel kiln, which defines the position and the upstream of a kiln head as the kiln car entering the tunnel kiln, and comprises the following components arranged in sequence from the kiln head to the kiln tail:
the preheating zone 1 is positioned on the side of a kiln head closed door, and a circulating flue gas outlet is arranged on the upstream side of the preheating zone 1;
a fresh air inlet is arranged at the downstream side of the burning zone 2;
a cooling zone 3, the downstream side of which is provided with a circulating flue gas inlet;
the hot air belt 4 is positioned on the side of the kiln tail sealing door, a cold air inlet is arranged on the downstream side of the hot air belt 4, and a hot air outlet is arranged on the upstream side of the hot air belt;
a first circulating heat-insulating pipeline 5 is arranged outside the kiln, a circulating fan 6 is arranged on the first circulating heat-insulating pipeline 5, an air inlet of the circulating fan 6 is communicated with the circulating flue gas outlet, an air outlet of the circulating fan 6 is communicated with the circulating flue gas inlet, an air outlet of the circulating fan 6 is also communicated with a flue gas inlet of a flue gas treatment facility 7 through a flue gas treatment pipeline, and a flue gas outlet of the flue gas treatment facility 7 is communicated with a smoke exhaust chimney 8;
an air cooler 9 is also arranged outside the kiln, and an air outlet of the air cooler 9 is communicated with the cold air inlet;
a fresh air fan 10 is further arranged outside the kiln, an air inlet of the fresh air fan 10 is communicated with the hot air outlet, an air outlet of the fresh air fan 10 is communicated with the fresh air inlet, and the fresh air is sprayed into the kiln to form a first air curtain;
an air curtain fan 11 is further arranged outside the kiln, an air inlet of the air curtain fan 11 is communicated with the hot air outlet, an air outlet of the air curtain fan 11 is communicated with the air inlet of the air curtain and sprayed into the kiln to form a second air curtain, the upstream side of the second air curtain is the cooling zone 3, and the downstream side of the second air curtain is the hot air zone 4;
a drying chamber 12, a drying fan 13 and a dehumidifying fan 14 are further arranged outside the kiln, the drying chamber 12 and the tunnel kiln are arranged in parallel, the drying chamber 12 is provided with an air inlet and an air outlet, the air inlet of the drying fan 13 is communicated with the hot air outlet, the air outlet of the drying fan 13 is communicated with the air inlet of the drying chamber 12, the air outlet of the drying chamber 12 is communicated with the air inlet of the dehumidifying fan 14, and the air outlet of the dehumidifying fan 14 is communicated with a dehumidifying chimney 15;
and the air volume ratio of the drying fan 13 to the fresh air fan 10 is a drying coefficient and is controlled to be 2-7.
In the technical scheme, a tunnel kiln is connected with a drying chamber 12, green bricks are stacked on kiln cars, a plurality of kiln cars are connected in series in the drying chamber 12 for drying, the moisture content of the green bricks entering the kiln is reduced to be within 5 percent, the moisture content of circulating flue gas is effectively controlled, the operation is convenient, a kiln car platform adopts a two-layer platform design, an air duct is arranged in the two-layer platform, hot air is directly sprayed into the air duct in the two-layer platform in the calcining process and then returns to a piled brick pile stacked on the upper layer, the ventilation in the kiln is facilitated, the kiln car is more suitable for firing medium and high-grade products such as square bricks, the dried kiln cars sequentially pass through a preheating zone 1, a firing zone 2, a cooling zone 3 and a hot air zone 4 of the calcining kiln, the drying coefficient is an important index for measuring the drying efficiency of the drying chamber 12 and is also an important index for measuring the drying efficiency of the calcining kiln, the finished brick can be better cooled by increasing the hot air zone 4 through the thermal efficiency, and the provided hot air does not contain flue gas, the drying air of the drying chamber 12 does not contain sulfur, and meanwhile, the dust content is easy to reach the standard, so that the drying air can be generally and directly discharged, the more strict environmental protection requirement is met, meanwhile, the air handling air quantity is reduced, and the cost is reduced.
The preheating zone 1 in the tunnel kiln is internally preheated by adopting flue gas, the circulating flue gas and the green bricks on the kiln car in the preheating zone 1 perform countercurrent heat exchange and drying, and the flue gas is circulated for preheating, so that the air speed in the kiln can be increased without increasing the oxygen content, the heat exchange between the flue gas and the green bricks is facilitated, and the low oxygen content and even the reduction atmosphere can be effectively controlled under the condition of meeting the requirement of heat exchange.
Independent calcination is adopted in the burning zone 2 in the tunnel kiln, fresh air with high oxygen content is sprayed into the burning zone 2 as far as possible to increase the oxygen content in the burning zone 2, the oxygen content in the smoke is controlled by controlling the fresh air quantity in the burning zone 2, the smoke is controlled in a reducing atmosphere or an oxidizing atmosphere, the appearance of the product is bluish or reddish, and the color control can also be realized.
The cooling zone 3 in the tunnel kiln is cooled by flue gas, the circulating flue gas and bricks on a kiln car of the cooling zone 3 perform countercurrent heat exchange, and the whole flue gas is subjected to circulating cooling without adding fresh air, so that the air quantity of the circulating cooling and preheating does not influence the air quantity of calcination, the circulating flue gas quantity can be increased, and the heat efficiency of the kiln is improved.
The hot air zone 4 in the tunnel kiln adopts cold air for heat exchange, all the inlet air of the hot air zone 4 is the cold air and is pure air, the baked bricks are continuously cooled in the hot air zone 4 by heat exchange to generate hot air which is supplied to the drying chamber 12 for drying the green bricks after heat exchange, and the fresh air of the baking zone 2 can be supplied to the kiln for calcination, thereby ensuring that the temperature of finished bricks discharged from the kiln is low, and the heat is utilized to the maximum extent, so as to achieve the purpose of energy conservation.
The flue gas circulation technology based on the technical scheme can greatly reduce the discharge amount of flue gas, reduce the flue gas treatment capacity, reduce the heat taken away by unnecessary flue gas discharge, and achieve a stricter energy-saving standard.
In another technical solution, as shown in fig. 2, a heat exchanger 20 is further disposed on the first circulating heat-insulating pipeline 5, and is provided with a flue gas inlet, a flue gas outlet, a cold air inlet, and a hot air outlet;
the circulating flue gas outlet is communicated with the flue gas inlet of the heat exchanger 20, and the air inlet of the circulating fan 6 is communicated with the flue gas outlet of the heat exchanger 20;
the air outlet of the fresh air blower 10 is communicated with the cold air inlet of the heat exchanger 20, and the fresh air inlet is communicated with the hot air outlet of the heat exchanger 20.
In the above technical solution, when the heat exchanger 20 is a boiler, steam or hot water is supplied to the outside, and the heat exchanger can also be used as a heater of a power generation boiler; when the heat exchanger 20 is a gas heat exchanger, the fresh air is heated through the heat exchanger 20, so that the air inlet temperature of the cooling zone 3 is controlled, the heat entering the kiln is reduced, the outlet temperature of the circulating flue gas is indirectly reduced, and the condition that the adobes entering the preheating zone 1 exchange heat with the flue gas with overhigh temperature to cause large adobes temperature difference and damage is avoided.
In another technical scheme, the cross section of the burning zone 2 is increased compared with the preheating zone 1, the cooling zone 3 and the hot air zone 4, and a bypass air duct is formed at the side part or the top part of the burning zone 2.
In the technical scheme, the side part of the section of the burning zone 2 is enlarged, and the sectional area of the ventilation channel is increased. The lateral part or the top of the brick pillar in the firing zone 2 kiln is additionally provided with a bypass air duct, so that the circulating flue gas bypasses the first air curtain as much as possible and passes through the bypass air duct, and the oxygen content in the fresh air is diluted by passing through the middle of the brick pillar as little as possible.
In another technical scheme, during internal combustion roasting, fresh air is air or oxygen-enriched air and is injected into the kiln through the fresh air inlet; when external combustion roasting is carried out, fresh air and fuel are mixed and then combusted to generate hot air, and the hot air is sprayed into the kiln through the fresh air inlet; when internal combustion and external combustion are mixed and roasted, the fuel is sprayed into the kiln along with fresh air from the fresh air inlet.
In the technical scheme, the oxygen content of the combustion zone 2 is increased, and the internal combustion fuel or the external combustion fuel is fully mixed and combusted when the oxygen content is high, so that the combustion efficiency is improved.
In another technical scheme, as shown in fig. 3, movable stop gates 19 are arranged among the preheating zone 1, the burning zone 2, the cooling zone 3 and the hot air zone 4, when the kiln car travels, after all fans stop operating, all the movable stop gates 19 are opened simultaneously or sequentially, when the kiln car stops, all the movable stop gates 19 are closed simultaneously, four independent spaces are formed by the preheating zone 1, the burning zone 2, the cooling zone 3 and the hot air zone 4, and all the fans start operating;
a high-temperature flue gas inlet is also arranged at the downstream side of the preheating zone 1;
the fresh air inlet at the downstream side of the burning zone 2 is replaced by a hot air inlet, and the hot flue gas outlet is also arranged at the upstream side of the burning zone 2;
a high-temperature flue gas outlet is also formed in the upstream side of the cooling zone 3;
the air curtain fan 11 and the air curtain air inlet are omitted;
a second circulating heat-insulating pipeline 16 is further arranged outside the kiln, and the second circulating heat-insulating pipeline 16 is respectively communicated with the high-temperature flue gas inlet and the high-temperature flue gas outlet;
the air outlet of the fresh air fan 10 is communicated with the hot air inlet;
the flue gas inlet of the flue gas treatment facility 7 is communicated with the hot flue gas outlet;
the oxygen content in the flue gas treatment pipeline is an oxygen index, and the control range is 0-17%;
the carbon monoxide content in the first circulation heat-preservation pipeline 5 and the second circulation heat-preservation pipeline 16 is a reduction index, and the control range is 0-7.5% during firing.
In the technical scheme, the interior of the kiln is sealed in sections by arranging the kiln head sealing door, the kiln tail sealing door and the movable stop door 19, the kiln head sealing door and the kiln tail sealing door are preferably double-layer kiln doors, each group of double-layer kiln doors are separated by the distance of one kiln car, so that the interior of the kiln can be better sealed, the air volume and the contents of oxygen and carbon monoxide can be more easily controlled, by arranging the second circulating heat-insulating pipeline 16, the circulating flue gas and the fresh air are separately operated and completely independently operated, so that the oxygen content is not limited by the circulating air volume, the oxygen content can be completely independently controlled without influencing the reduction control of the circulating flue gas, when the burning zone 2 burns independently, the oxygen content of the discharged flue gas is controlled independently by controlling the oxygen index, so that the excess air coefficient is reduced as much as possible, the heat taken away by the discharged flue gas is reduced, the processing capacity of the flue gas is reduced, and the equipment investment is reduced.
The key point that the flue gas is in the reducing atmosphere in the cooling zone 3 is that the content of carbon monoxide in the circulating flue gas is independently controlled by controlling the reducing index, so that the reducing capability of the circulating flue gas is controllable, and the purpose of cooling the baked bricks in the reducing atmosphere to a certain degree is achieved to achieve the purpose of producing the grey bricks.
In actual production, the gradient change of the product between red and cyan can be realized by controlling the oxygen content and the reducing atmosphere in the circulating flue gas, and the specific mode is as follows:
the proportion of oxygen and reducing gas in the circulating flue gas is controlled, wherein when the reducing gas is more than 0.5 percent and the oxygen is less than 1 percent, the cyan on the surface of the brick is more than 80 percent, when the reducing gas is less than 0.5 percent and the oxygen is less than 1 percent, the surface of the brick can be partially cyan, the area proportion is less than 80 percent, the cyan and the red can be changed in a gradient way along with the change of the proportion, of course, the color is also related to the cooling speed, and the higher the cooling speed is, the higher the red proportion is.
In another technical solution, as shown in fig. 4, the flue gas treatment pipeline is further provided with a heat exchanger 20, which is provided with a flue gas inlet, a flue gas outlet, a cold air inlet and a hot air outlet;
the hot flue gas outlet is communicated with the flue gas inlet of the heat exchanger 20, and the flue gas inlet of the flue gas treatment facility 7 is communicated with the flue gas outlet of the heat exchanger 20;
the air outlet of the fresh air machine 10 is communicated with the cold air inlet of the heat exchanger 20, and the hot air inlet is communicated with the hot air outlet of the heat exchanger 20.
In the above technical scheme, the discharged flue gas is directly discharged from the burning zone 2, a lot of heat can be taken away due to high temperature of the discharged flue gas, the heat is effectively recovered through the heat exchanger 20, and the temperature of the hot air is continuously increased, so that the purpose of energy saving is achieved, the energy of the heat exchanger 20 can be supplied with the external hot air by the fresh air, and hot water or a steam boiler can be used for absorbing the energy and supplying the external heat.
In another technical scheme, the reduction index is controlled within the range of 1.0-7.5% when the black bricks are fired.
In the technical scheme, when the green brick is fired, the reduction index is controlled to be 1.0-7.5%, so that the fired brick is reduced and cooled in the cooling process, and the green brick is fired in the tunnel kiln.
In another technical scheme, as shown in fig. 5, a third circulating heat-preserving pipeline 17 is further arranged outside the kiln, the third circulating heat-preserving pipeline 17 is respectively communicated with the air outlet of the circulating fan 6 and the hot air inlet, and a flow regulating valve 18 is further arranged on the third circulating heat-preserving pipeline 17.
In the technical scheme, a part of smoke is added in the burning zone 2, so that the oxygen content of the burning zone 2 during burning is reduced, the generation of nitrogen oxides is reduced, and the higher environmental protection requirement is met.
In another technical scheme, inward protruding strips are arranged on the top and side walls of the preheating zone 1 and the cooling zone 3 to form a corrugated structure.
In the technical scheme, the wind resistance at the side of the kiln is increased, more wind passes through piled seams formed by piled green bricks, and ineffective ventilation is reduced.
In another technical scheme, a boiler is arranged at the top of the burning zone 2, and boiler calandria and the flue gas of the burning zone 2 are in contact heat exchange.
In the technical scheme, the heat taken away by the discharged flue gas is reduced, and the heat of the flue gas is recovered.
The number of apparatuses and the scale of the process described herein are intended to simplify the description of the present invention. Applications, modifications and variations of the present invention will be apparent to those skilled in the art.
While embodiments of the invention have been described above, it is not limited to the applications set forth in the description and the embodiments, which are fully applicable in various fields of endeavor to which the invention pertains, and further modifications may readily be made by those skilled in the art, it being understood that the invention is not limited to the details shown and described herein without departing from the general concept defined by the appended claims and their equivalents.

Claims (10)

1. Energy-conserving tunnel cave of flue gas circulation, its characterized in that includes that the direction sets gradually from the kiln head to the kiln tail:
the preheating zone is positioned on the side of the kiln head closed door, and a circulating flue gas outlet is arranged on the upstream side of the preheating zone;
a fresh air inlet is arranged at the downstream side of the burning zone;
a cooling zone, the downstream side of which is provided with a circulating flue gas inlet;
the hot air belt is positioned on the side of the kiln tail sealing door, a cold air inlet is arranged on the downstream side of the hot air belt, and a hot air outlet is arranged on the upstream side of the hot air belt;
the kiln is provided with a first circulating heat-insulating pipeline outside the kiln, the first circulating heat-insulating pipeline is provided with a circulating fan, an air inlet of the circulating fan is communicated with the circulating flue gas outlet, an air outlet of the circulating fan is communicated with the circulating flue gas inlet, an air outlet of the circulating fan is also communicated with a flue gas inlet of a flue gas treatment facility through a flue gas treatment pipeline, and a flue gas outlet of the flue gas treatment facility is communicated with a smoke exhaust chimney;
an air cooler is arranged outside the kiln, and an air outlet of the air cooler is communicated with the cold air inlet;
a fresh air fan is arranged outside the kiln, an air inlet of the fresh air fan is communicated with the hot air outlet, an air outlet of the fresh air fan is communicated with the fresh air inlet, and the fresh air is sprayed into the kiln to form a first air curtain;
an air curtain fan is further arranged outside the kiln, an air inlet of the air curtain fan is communicated with the hot air outlet, an air outlet of the air curtain fan is communicated with the air inlet of the air curtain and sprayed into the kiln to form a second air curtain, the upstream side of the second air curtain is the cooling zone, and the downstream side of the second air curtain is the hot air zone;
the drying chamber and the tunnel kiln are arranged in parallel, the drying chamber is provided with an air inlet and an air outlet, the air inlet of the drying fan is communicated with the hot air outlet, the air outlet of the drying fan is communicated with the air inlet of the drying chamber, the air outlet of the drying chamber is communicated with the air inlet of the dehumidifying fan, and the air outlet of the dehumidifying fan is communicated with a dehumidifying chimney;
and the air volume ratio of the drying fan to the fresh air fan is a drying coefficient and is controlled to be 2-7.
2. The flue gas circulation energy-saving tunnel kiln of claim 1, wherein the first circulation heat-preservation pipeline is further provided with a heat exchanger which is provided with a flue gas inlet, a flue gas outlet, a cold air inlet and a hot air outlet;
the circulating flue gas outlet is communicated with the flue gas inlet of the heat exchanger, and the air inlet of the circulating fan is communicated with the flue gas outlet of the heat exchanger;
the air outlet of the fresh air fan is communicated with the cold air inlet of the heat exchanger, and the fresh air inlet is communicated with the hot air outlet of the heat exchanger.
3. The flue gas circulation energy-saving tunnel kiln of claim 1 or 2, wherein the cross section of the burning zone is enlarged compared with the preheating zone, the cooling zone and the hot air zone, and a bypass air duct is formed at the side part or the top part of the burning zone.
4. The flue gas circulation energy-saving tunnel kiln of claim 1 or 2, wherein during internal combustion roasting, fresh air is air or oxygen-enriched air and is injected into the kiln through the fresh air inlet; when external combustion roasting is carried out, fresh air and fuel are mixed and then combusted to generate hot air, and the hot air is sprayed into the kiln through the fresh air inlet; when internal combustion and external combustion are mixed and roasted, the fuel is sprayed into the kiln along with fresh air from the fresh air inlet.
5. The flue gas circulation energy-saving tunnel kiln as claimed in claim 1, wherein movable stop doors are arranged among the preheating zone, the burning zone, the cooling zone and the hot air zone, when the kiln car travels, all the movable stop doors are opened simultaneously or sequentially after all the fans stop operating, when the kiln car stops, all the movable stop doors are closed simultaneously, the preheating zone, the burning zone, the cooling zone and the hot air zone form four independent spaces, and all the fans start to operate;
a high-temperature flue gas inlet is also arranged at the downstream side of the preheating zone;
the fresh air inlet on the downstream side of the burning zone is replaced by a hot air inlet, and the hot flue gas outlet is also arranged on the upstream side of the burning zone;
a high-temperature flue gas outlet is also formed in the upstream side of the cooling zone;
the air curtain fan and the air curtain air inlet are omitted;
a second circulating heat-insulating pipeline is arranged outside the kiln and is respectively communicated with the high-temperature flue gas inlet and the high-temperature flue gas outlet;
the air outlet of the fresh air fan is communicated with the hot air inlet;
the flue gas inlet of the flue gas treatment facility is communicated with the hot flue gas outlet;
the oxygen content in the flue gas treatment pipeline is an oxygen index, and the control range is 0-17%;
the carbon monoxide content in the first circulation heat-insulation pipeline and the second circulation heat-insulation pipeline is a reduction index, and the control range is 0-7.5% during firing.
6. The flue gas circulation energy-saving tunnel kiln of claim 5, wherein the flue gas treatment pipeline is further provided with a heat exchanger which is provided with a flue gas inlet, a flue gas outlet, a cold air inlet and a hot air outlet;
the hot flue gas outlet is communicated with the flue gas inlet of the heat exchanger, and the flue gas inlet of the flue gas treatment facility is communicated with the flue gas outlet of the heat exchanger;
the air outlet of the fresh air machine is communicated with the cold air inlet of the heat exchanger, and the hot air inlet is communicated with the hot air outlet of the heat exchanger.
7. The flue gas circulation energy-saving tunnel kiln of claim 5 or 6, wherein the reduction index is controlled within a range of 1.0 to 7.5% when the green bricks are fired.
8. The flue gas circulation energy-saving tunnel kiln of claim 5, wherein a third circulation heat preservation pipeline is arranged outside the kiln, the third circulation heat preservation pipeline is respectively communicated with the air outlet of the circulation fan and the hot air inlet, and a flow regulating valve is further arranged on the third circulation heat preservation pipeline.
9. The flue gas circulation energy-saving tunnel kiln of claim 1, wherein the top and side walls of the preheating zone and the cooling zone are provided with inward protruding strips to form a corrugated structure.
10. The flue gas circulation energy-saving tunnel kiln of claim 1, wherein the top of the burning zone is provided with a boiler, and a boiler exhaust pipe is in contact with flue gas of the burning zone for heat exchange.
CN202210565351.1A 2022-05-23 2022-05-23 Flue gas circulation energy-saving tunnel kiln Pending CN114877672A (en)

Priority Applications (1)

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Application Number Priority Date Filing Date Title
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Cited By (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
CN115790226A (en) * 2022-11-21 2023-03-14 乌兰察布市旭峰炭素科技有限公司 Heat transfer oil heat exchange system for carbon production
CN116086176A (en) * 2023-02-09 2023-05-09 天津大学 Device and process for modifying calcined clay of low-carbon environment-friendly tunnel kiln

Cited By (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
CN115790226A (en) * 2022-11-21 2023-03-14 乌兰察布市旭峰炭素科技有限公司 Heat transfer oil heat exchange system for carbon production
CN115790226B (en) * 2022-11-21 2023-12-26 乌兰察布市旭峰炭素科技有限公司 Heat transfer oil heat exchange system for carbon production
CN116086176A (en) * 2023-02-09 2023-05-09 天津大学 Device and process for modifying calcined clay of low-carbon environment-friendly tunnel kiln

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