CN112146447A - Method for preventing ash spraying of air release valve of double-chamber kiln - Google Patents
Method for preventing ash spraying of air release valve of double-chamber kiln Download PDFInfo
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- CN112146447A CN112146447A CN202010967920.6A CN202010967920A CN112146447A CN 112146447 A CN112146447 A CN 112146447A CN 202010967920 A CN202010967920 A CN 202010967920A CN 112146447 A CN112146447 A CN 112146447A
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- 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
- F27D3/00—Charging; Discharging; Manipulation of charge
- F27D3/15—Tapping equipment; Equipment for removing or retaining slag
- F27D3/1545—Equipment for removing or retaining slag
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- C—CHEMISTRY; METALLURGY
- C04—CEMENTS; CONCRETE; ARTIFICIAL STONE; CERAMICS; REFRACTORIES
- C04B—LIME, MAGNESIA; SLAG; CEMENTS; COMPOSITIONS THEREOF, e.g. MORTARS, CONCRETE OR LIKE BUILDING MATERIALS; ARTIFICIAL STONE; CERAMICS; REFRACTORIES; TREATMENT OF NATURAL STONE
- C04B2/00—Lime, magnesia or dolomite
- C04B2/10—Preheating, burning calcining or cooling
- C04B2/108—Treatment or selection of the fuel therefor
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- C—CHEMISTRY; METALLURGY
- C04—CEMENTS; CONCRETE; ARTIFICIAL STONE; CERAMICS; REFRACTORIES
- C04B—LIME, MAGNESIA; SLAG; CEMENTS; COMPOSITIONS THEREOF, e.g. MORTARS, CONCRETE OR LIKE BUILDING MATERIALS; ARTIFICIAL STONE; CERAMICS; REFRACTORIES; TREATMENT OF NATURAL STONE
- C04B2/00—Lime, magnesia or dolomite
- C04B2/10—Preheating, burning calcining or cooling
- C04B2/12—Preheating, burning calcining or cooling in shaft or vertical furnaces
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- 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
- F27D17/008—Arrangements for using waste heat; Arrangements for using, or disposing of, waste gases cleaning gases
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- 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
- F27D19/00—Arrangements of controlling devices
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- 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
- F27D7/00—Forming, maintaining, or circulating atmospheres in heating chambers
- F27D7/02—Supplying steam, vapour, gases, or liquids
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- 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
- F27D19/00—Arrangements of controlling devices
- F27D2019/0028—Regulation
- F27D2019/0034—Regulation through control of a heating quantity such as fuel, oxidant or intensity of current
- F27D2019/004—Fuel quantity
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- 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
- Y02A—TECHNOLOGIES FOR ADAPTATION TO CLIMATE CHANGE
- Y02A50/00—TECHNOLOGIES FOR ADAPTATION TO CLIMATE CHANGE in human health protection, e.g. against extreme weather
- Y02A50/20—Air quality improvement or preservation, e.g. vehicle emission control or emission reduction by using catalytic converters
- Y02A50/2351—Atmospheric particulate matter [PM], e.g. carbon smoke microparticles, smog, aerosol particles, dust
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- Chemical & Material Sciences (AREA)
- Ceramic Engineering (AREA)
- Mechanical Engineering (AREA)
- General Engineering & Computer Science (AREA)
- Physics & Mathematics (AREA)
- Thermal Sciences (AREA)
- Materials Engineering (AREA)
- Structural Engineering (AREA)
- Organic Chemistry (AREA)
- Environmental & Geological Engineering (AREA)
- Waste-Gas Treatment And Other Accessory Devices For Furnaces (AREA)
Abstract
The invention discloses a method for preventing ash spraying of air release valves of a double-hearth kiln, which comprises the following steps of using a device for preventing ash spraying of the air release valves of the double-hearth kiln: A. when the system cuts off the gas delivery to the kiln, opening the electric control valve to deliver the gas in the kiln to the dust remover, and reducing the pressure in the kiln to be below 10kpa before entering the reversing period; B. blowing the dust removal cloth bag for 1 time/hour; C. opening a combustion air release valve for 3 seconds and then opening a cooling air release valve during reversing; D. controlling the granularity of the raw materials; E. and (3) adopting a 'feeding during combustion' mode, and adjusting the opening and closing action time of each valve to be 4-5 seconds. Compared with the prior art, the invention realizes that the gas in the kiln is released to the dust remover in advance during the reversing of the kiln, recovers the dust sprayed by the combustion air release valve, reduces the pressure in the kiln by means of technological operation improvement and the like, and prevents the combustion air release valve and the cooling air release valve from generating ash spraying phenomenon.
Description
Technical Field
The invention relates to the technical field of metallurgical production, in particular to a method for preventing ash spraying of an air release valve of a double-hearth kiln.
Background
The double-hearth kiln is provided with two hearths, and the lower part of a calcining zone of the hearths is provided with a middle channel which is communicated with each other. In the combustion operation process, two kilns of the double-hearth kiln carry out function conversion every 12-14 minutes, namely when one kiln is in a calcining state, the other kiln is in a heat storage state. As shown in fig. 1, fig. 2, fig. 3, fig. 4 and fig. 5, the double-hearth kiln comprises a kiln hearth a and a kiln hearth B which are connected through a middle channel, combustion air reversing valves 2 are respectively arranged at the tops close to the kiln hearth a and the kiln hearth B, the combustion air reversing valves 2 are connected with an exhaust gas pipe 3, a combustion air branch pipe 4 is connected between the two combustion air reversing valves 2, and the combustion air branch pipe 4 is sequentially connected with a combustion air regulating valve, a combustion air release valve 11 and a combustion air blower through a combustion air main pipe 1; the lower parts of the kiln chamber A and the kiln chamber B are respectively provided with a discharging platform 6, a discharging gate 9 and a cooling air branch pipe 10 for connecting the kiln chamber A and the kiln chamber B, and the cooling air branch pipe 10 is sequentially connected with a cooling air release valve 7 and a cooling fan through a cooling air main pipe 8; spray guns 5 are distributed on the upper parts of the kiln chamber A and the kiln chamber B along the circumferential direction, and the spray guns 5 are connected with a gas ring pipe outside the kiln; the spray gun 5 is connected with a spray gun cooling air reversing valve through a cooling air pipe.
Under the condition of kiln combustion, the system starts a combustion-supporting fan and a cooling fan, combustion-supporting air W1 is fed into the kiln chamber A from top to bottom through a combustion-supporting air reversing valve 2 at the top of the kiln chamber A, and when the combustion-supporting air W1 passes through a preheating zone, the heat exchange is carried out with stones with higher temperature at the top of the kiln chamber A, so that the stones with higher temperature are heated. When the combustion-supporting air W1 reaches the calcining zone of the kiln, the combustion-supporting air is mixed with the coal gas conveyed by the spray gun 5 of the kiln chamber A, and the coal gas reaches the ignition point and immediately burns to generate heat because the temperature of stone materials at the lower end of the spray gun 5 is higher and is close to about 700 ℃, and the kiln chamber A is a combustion chamber at the moment. As the kiln bottom discharge platform 6 discharges, the column moves down and the combustion air W1, the rock material, and the combustion products flow downward together, a process known as "co-current". In the parallel flow state, the combustion-supporting air W1 can give full play to the thermal efficiency, and simultaneously, the gas combustion flame can fully contact with stone materials, so that the high thermal efficiency is kept. Near the cooling zone, near below the suspension cylinder, the limestone surface temperature gradually decreases. When lime enters the cooling zone after being combusted, cooling air W2 cools the lime, heat exchange is carried out, the surface temperature of the lime is reduced to a certain degree, then a finished product is discharged into a lime small bin, and the lime is discharged by a kiln bottom feeder. And after heat exchange is carried out between the cooling air W2 and the calcined lime, the temperature is raised, the cooling air is mixed with combustion products through an intermediate channel and enters a kiln chamber B, the flue gas E passes through a calcining zone from bottom to top in the kiln chamber B and reaches the top of the kiln chamber B, and the kiln chamber B is a heat storage chamber at the moment. At the top of the kiln chamber B, stones added by the rotary hopper are equivalent to a large heat exchanger, and the temperature of the flue gas E is reduced to about 160-180 ℃ through heat exchange and is discharged from the top of the kiln. The temperature of the rock material is raised to about 700 ℃ by preheating the flue gas E in the heat accumulation chamber. In a high-capacity state, a production mode of "charge during combustion" can be selected. In this mode, the system charges the hot storage chamber 3 times during the combustion process, and each period takes about 12-14 minutes to complete.
When a calcination cycle is completed, the system enters a turnaround that takes approximately 45 seconds. And the burnout time is about 30 seconds before the reversing period, the burnout time can be adjusted through system parameters, the system can immediately cut off the gas introduced into the kiln, and the nitrogen is adopted to purge the gas ring pipe and the spray gun 5 so as to clean residual gas. In the reversing period, a combustion air release valve 11 and a cooling air release valve 7 of the double-hearth kiln are opened successively to release the pressure in the kiln; simultaneously, the discharging gate plate 9 is opened, and lime blocks stored on the upper part of the discharging gate plate 9 are discharged into the small storage bin. And switching the position of a flashboard of a reversing valve of the cooling air of the spray gun, starting to cool the spray gun 5 converted into the heat storage chamber, actuating the flashboard of the reversing valve 2 of the combustion air to realize the function conversion of the heat storage chamber and the combustion chamber, and starting to calcine again in the next period.
When gas is cut off in the reversing period or stopping production of the kiln, when the kiln releases gas in the kiln through the combustion air release valve 11 and the cooling air release valve 7, a large amount of dust can be instantly sprayed out from the combustion air release valve 11 and the cooling air release valve 7 along with the gas in the kiln to influence the surrounding environment when function conversion is implemented. This phenomenon is common in parallel-flow regenerative kilns, such as dual-chamber kilns and dual-D kilns, and therefore a method for preventing dust injection of air release valves of the dual-chamber kilns is urgently needed, so as to avoid environmental pollution.
Disclosure of Invention
The invention aims to provide a method for preventing dust from being sprayed by air release valves of a double-hearth kiln, which can solve the problem of environmental pollution caused by instant spraying of a large amount of dust along with gas in the kiln from combustion air release valves and cooling air release valves when the function of the kiln is switched.
In order to solve the problems, the invention adopts the technical scheme that: the method for preventing the ash spraying of the air release valves of the double-hearth kiln comprises the steps of using an ash spraying device for preventing the air release valves of the double-hearth kiln, wherein the ash spraying device for preventing the air release valves of the double-hearth kiln is provided with two combustion-supporting air reversing valves which are respectively arranged at the tops of a kiln hearth A and a kiln hearth B and connected with an exhaust gas pipe, the two combustion-supporting air reversing valves are connected through combustion-supporting air branch pipes, and the combustion-supporting air branch pipes are connected with the combustion-supporting air release valves and a combustion-supporting fan through a combustion-supporting air main pipe; the lower parts of the kiln chamber A and the kiln chamber B are connected through a cooling air branch pipe, and the cooling air branch pipe is connected with a cooling air release valve and a cooling fan through a cooling air main pipe; an exhaust pipe connected with the waste gas pipe is arranged on the combustion air branch pipe, and an electric control valve is arranged on the exhaust pipe; the exhaust port of the combustion-supporting air release valve is connected with a dust removal filter, a plurality of rows of dust removal cloth bags are arranged in the dust removal filter, a compressed air pulse device is arranged on each dust removal cloth bag, and the bottom of the dust removal filter is connected with a star-shaped ash discharge valve through an ash bucket;
the specific method comprises the following steps:
A. when the system cuts off the coal gas conveyed to the kiln, namely before the system enters the burnout time, the system controls to open the electric control valve, the gas in the kiln is conveyed to the dust remover through the exhaust pipe and the waste gas pipe, and the pressure in the kiln is reduced to be below 10kpa before the kiln enters the reversing period; then opening the combustion-supporting air release valve, adjusting the opening speed of the combustion-supporting air release valve to 8-10 seconds to realize slow release of gas in the kiln, and closing the electric control valve after confirming that the combustion-supporting air release valve is opened;
B. the compressed air pulse device blows the dust removal cloth bag for 1 time/hour, and dust is conveyed into a finished product system through the star-shaped dust discharge valve;
C. opening a combustion air release valve for 3 seconds and then opening a cooling air release valve during reversing;
D. the granularity of the raw materials entering the kiln is controlled to be more than 80 percent of the weight of the raw materials of particles with the diameter of 40-80 mm;
E. the mode of 'feeding during combustion' is adopted, namely, during setting of calcination, the system feeds materials to the heat storage chamber, the action time of opening and closing the combustion-supporting air reversing valve, the discharging gate plate and the cooling air release valve during reversing is reduced to 4-5 seconds through adjustment, the reversing period time of the kiln is reduced to 35-40 seconds, the cumulative combustion time of conveying coal gas and combustion-supporting air to the kiln every day is prolonged to 1960-2450 seconds, the gas pressure value during calcination in the kiln is reduced, and ash spraying is reduced.
In the above technical solution of the method for preventing ash ejection of the air release valve of the double-hearth kiln, a more specific technical solution may also be: setting the combustion air coefficient to be 1.0-1.1, observing the temperature curve of the optical pyrometer on the middle channel of the kiln, and controlling the difference between the highest temperature and the lowest temperature of the optical pyrometer to be less than or equal to 50 ℃ in the operation period; setting the coefficient of cooling air to be 0.65-0.75, and controlling the temperature of the ash-out finished product to be lower than 200 ℃.
Further, the heat value of the fuel of the coal gas used for the kiln combustion is 7000kJ/m3The above.
Further, the electric control valve adopts a hydraulic butterfly valve or a pneumatic butterfly valve controlled by a solenoid valve.
Due to the adoption of the technical scheme, compared with the prior art, the invention has the following beneficial effects:
1. according to the invention, by opening the electric control valve, the gas in the kiln is released to the dust remover in advance through the exhaust pipe and the waste gas pipe during the reversing period of the kiln. Dust sprayed from the combustion air release valve is recycled through the dust removal filter, pressure in the kiln is reduced through means of raw material screening, process operation improvement, valve action adjustment and the like, the ash spraying phenomenon of the combustion air release valve and the cooling air release valve is prevented, and the environment pollution is avoided. The operating pressure of the kiln is reduced, the furnace condition of the kiln is improved, the quality of finished products is improved, and the productivity is improved.
2. The ranges of the combustion air coefficient and the cooling air coefficient are set, so that the gas is fully combusted, and the gas conveying amount entering the kiln is reduced.
3. The calorific value of the fuel of the coal gas used for the kiln combustion is 7000kJ/m3Therefore, the conveying gas amount is further reduced, the pressure in the kiln is reduced, and the ash spraying of a combustion air release valve and a cooling air release valve is reduced.
4. The electric control valve adopts a hydraulic butterfly valve or a pneumatic butterfly valve controlled by an electromagnetic valve, the hydraulic butterfly valve and the pneumatic butterfly valve have good sealing performance, and the opening of the valve can be flexibly adjusted.
Drawings
FIG. 1 is a schematic view of a double-hearth kiln.
FIG. 2 is a schematic view of gas flow when a kiln chamber A is a combustion chamber and a kiln chamber B is a heat storage chamber in the calcination process of a double-chamber kiln.
FIG. 3 is a schematic diagram of the positions of two combustion-supporting air reversing valve gate plates when a kiln chamber A is a combustion chamber and a kiln chamber B is a heat storage chamber in the process of calcining a double-chamber kiln.
FIG. 4 is a schematic view of gas flow when a kiln chamber A is a heat storage chamber and a kiln chamber B is a combustion chamber in the calcination process of a double-chamber kiln.
FIG. 5 is a schematic diagram showing the positions of two combustion-supporting air reversing valve gate plates when a kiln chamber A is a heat storage chamber and a kiln chamber B is a combustion chamber in the process of calcining a double-chamber kiln.
FIG. 6 is a schematic structural diagram of an ash injection device for preventing an air relief valve of a double-chamber kiln in the embodiment of the invention.
Fig. 7 is a schematic diagram of the connection of the electrically controlled valve in the embodiment of the present invention.
Fig. 8 is a schematic structural view of a dust removing filter in the embodiment of the present invention.
Detailed Description
The invention will be further described in detail with reference to the following examples:
as shown in figures 6, 7 and 8, the device for preventing the ash spraying of the air release valve of the double-hearth kiln comprises a kiln hearth A and a kiln hearth B which are connected through a middle channel, combustion air reversing valves 2 connected with an exhaust gas pipe 3 are respectively arranged at the tops close to the kiln hearth A and the kiln hearth B, the two combustion air reversing valves 2 are connected through combustion air branch pipes 4, and the combustion air branch pipes 4 are connected with a combustion air release valve 11 and a combustion air blower through a combustion air main pipe 1. The lower parts of the kiln chamber A and the kiln chamber B are respectively provided with a discharging platform 6, a discharging gate 9 and a cooling air branch pipe 10 for connecting the kiln chamber A and the kiln chamber B, and the cooling air branch pipe 10 is connected with a cooling air release valve 7 and a cooling fan through a cooling air main pipe 8. An exhaust pipe 13 connected with the exhaust pipe 3 is arranged on the combustion air branch pipe 4, the diameter of the exhaust pipe 13 is 300mm, and an electric control valve 14 is arranged on the exhaust pipe 13. Spray guns 5 are distributed on the upper parts of the kiln chamber A and the kiln chamber B along the circumferential direction, and the spray guns 5 are connected with a gas ring pipe outside the kiln. The exhaust port of the combustion-supporting air release valve 11 is connected with a dust removal filter 12, the dust removal filter 12 is provided with a dust removal box body, one side of the upper part of the dust removal box body is provided with an air inlet pipe 12-2, the other side of the upper part of the dust removal box body is provided with an air outlet pipe 12-3, ten dust removal cloth bags 12-1 are arranged in the dust removal box body, ten dust removal cloth bags 12-1 are arranged in each dust removal cloth bag, a compressed air pulse device is arranged on each dust cloth bag 12-1, and the bottom of.
Example 1
A method for preventing the ash spraying of the air release valve of the double-chamber kiln comprises the following steps of using an ash spraying device for preventing the air release valve of the double-chamber kiln as shown in figures 6, 7 and 8:
A. when the system cuts off the coal gas conveyed to the kiln, namely before the system enters the burnout time, the system controls to open the electric control valve 14, the gas in the kiln is conveyed to the dust remover through the exhaust pipe 13 and the waste gas pipe 3, and the pressure in the kiln is reduced to be below 10kpa before the kiln enters the reversing period; when the burnout time is short and the pressure in the kiln is reduced to a set value, further setting and prolonging the burnout time to realize the full reduction of the gas pressure in the kiln; then opening a combustion-supporting air release valve 11, adjusting the opening speed of the combustion-supporting air release valve 11 to 8 seconds to realize slow release of gas in the kiln, and closing an electric control valve 14 after confirming that the combustion-supporting air release valve 11 is opened, wherein the electric control valve 14 of the embodiment adopts a hydraulic butterfly valve controlled by an electromagnetic valve;
B. the compressed air pulse device blows the dust removal cloth bag 12-1 for 1 time/hour, and dust is conveyed into a finished product system through the star-shaped dust discharge valve 15, so that the dust is recovered; the gas discharged from the combustion air release valve 11 is filtered by a dust removal filter 12 and then discharged to the atmosphere;
C. during the reversing period, after the combustion-supporting air release valve 11 is opened for 3 seconds, the cooling air release valve 7 is opened, so that the combustion-supporting air release valve 11 is opened before the cooling air release valve 7, and the gas in the kiln is released to enter the dust removal filter 12;
D. washing the raw material by using a washing filtering system, screening the raw material by using a bar-type vibrating screen, and fully removing impurities such as silt in the raw material, so that the granularity of the raw material entering the kiln is controlled to be more than 80% of the weight of the raw material by controlling particles with the diameter of 40-80 mm, and blockage is avoided; setting the combustion air coefficient of the gangue to be 1.0, observing the temperature curve of the optical pyrometer on the middle channel of the kiln, and controlling the difference between the highest temperature and the lowest temperature of the optical pyrometer to be less than or equal to 50 ℃ in the operation period; the coefficient of cooling air is set to be 0.65, and the temperature of the ash-out finished product is controlled to be lower than 200 ℃, so that the aim of realizingThe gas conveying amount entering the kiln is reduced while the gas is fully combusted; the fuel calorific value of coal gas used for combustion of kiln is 7000kJ/m3Therefore, the amount of conveyed coal gas is further reduced, the pressure in the kiln is reduced, and the ash injection of the combustion air release valve 11 and the cooling air release valve 7 is reduced;
E. the mode of 'feeding during combustion' is adopted, namely, the system feeds the heat storage chamber in a calcining period, the action time of opening and closing the combustion-supporting air reversing valve 2, the discharging gate plate 9 and the cooling air release valve 7 during the reversing period is reduced to 4 seconds through adjustment, the reversing period time of the kiln is reduced to 35 seconds (the original reversing period feeding mode is adopted, the reversing time of the kiln is about 60 seconds per cycle), the cumulative combustion time of conveying coal gas and combustion-supporting air into the kiln every day is prolonged by 1960 seconds (calculated according to 98 cycles of the kiln every day), the gas pressure value during calcining in the kiln is reduced, and ash spraying is reduced. Under the setting of rated capacity, the input amount of fuel and combustion-supporting air is certain. When the burning time is prolonged, the fuel flow is reduced, and the pressure value of the kiln is reduced.
Example 2
A method for preventing the ash spraying of the air release valve of the double-chamber kiln comprises the following steps of using an ash spraying device for preventing the air release valve of the double-chamber kiln as shown in figures 6, 7 and 8:
A. when the system cuts off the coal gas conveyed to the kiln, namely before the system enters the burnout time, the system controls to open the electric control valve 14, the gas in the kiln is conveyed to the dust remover through the exhaust pipe 13 and the waste gas pipe 3, and the pressure in the kiln is reduced to be below 10kpa before the kiln enters the reversing period; when the burnout time is short and the pressure in the kiln is reduced to a set value, further setting and prolonging the burnout time to realize the full reduction of the gas pressure in the kiln; then opening a combustion-supporting air release valve 11, adjusting the opening speed of the combustion-supporting air release valve 11 to 10 seconds to realize slow release of gas in the kiln, and closing an electric control valve 14 after confirming that the combustion-supporting air release valve 11 is opened, wherein the electric control valve 14 of the embodiment adopts a pneumatic butterfly valve controlled by an electromagnetic valve;
B. the compressed air pulse device blows the dust removal cloth bag 12-1 for 1 time/hour, and dust is conveyed into a finished product system through the star-shaped dust discharge valve 15, so that the dust is recovered; the gas discharged from the combustion air release valve 11 is filtered by a dust removal filter 12 and then discharged to the atmosphere;
C. during the reversing period, after the combustion-supporting air release valve 11 is opened for 3 seconds, the cooling air release valve 7 is opened, so that the combustion-supporting air release valve 11 is opened before the cooling air release valve 7, and the gas in the kiln is released to enter the dust removal filter 12;
D. washing the raw material by using a washing filtering system, screening the raw material by using a bar-type vibrating screen, and fully removing impurities such as silt in the raw material, so that the granularity of the raw material entering the kiln is controlled to be more than 80% of the weight of the raw material by controlling particles with the diameter of 40-80 mm, and blockage is avoided; setting the combustion air coefficient of the gangue to be 1.1, observing the temperature curve of the optical pyrometer on the middle channel of the kiln, and controlling the difference between the highest temperature and the lowest temperature of the optical pyrometer to be less than or equal to 50 ℃ in the operation period; setting the coefficient of cooling air to be 0.75, controlling the temperature of the ash-out finished product to be lower than 200 ℃, and reducing the gas conveying quantity entering the kiln while realizing the full combustion of the coal gas; the fuel calorific value of coal gas used for combustion of kiln is 7000kJ/m3Therefore, the amount of conveyed coal gas is further reduced, the pressure in the kiln is reduced, and the ash injection of the combustion air release valve 11 and the cooling air release valve 7 is reduced;
E. the mode of 'feeding during combustion' is adopted, namely, the system feeds the heat storage chamber in a calcining period, the action time of opening and closing the combustion-supporting air reversing valve 2, the discharging gate plate 9 and the cooling air release valve 7 during the reversing period is reduced to 5 seconds through adjustment, the reversing period time of the kiln is reduced to 40 seconds (the original reversing period feeding mode is adopted, the reversing time of the kiln is about 60 seconds per cycle), the cumulative combustion time of conveying coal gas and combustion-supporting air into the kiln every day is prolonged by 2450 seconds (calculated according to 98 cycles of the kiln every day), the gas pressure value during calcining in the kiln is reduced, and ash spraying is reduced. Under the setting of rated capacity, the input amount of fuel and combustion-supporting air is certain. When the burning time is prolonged, the fuel flow is reduced, and the pressure value of the kiln is reduced.
According to the invention, by opening the electric control valve 14, the gas in the kiln is released to the dust remover through the exhaust pipe 13 and the waste gas pipe 3 in advance during the reversing period of the kiln. Dust sprayed out of the combustion air release valve 11 is recycled through the dust removal filter 12, the pressure in the kiln is reduced through the measures of raw material screening, process operation improvement, valve action adjustment, coal gas fuel calorific value improvement and the like, the ash spraying phenomenon of the combustion air release valve 11 and the cooling air release valve 7 is prevented, and the environment pollution is avoided; the operating pressure of the kiln is reduced, the furnace condition of the kiln is improved, the quality of finished products is improved, and the productivity is improved.
Claims (5)
1. A method for preventing ash spraying of air release valves of a double-hearth kiln comprises the steps that an ash spraying device for preventing the air release valves of the double-hearth kiln is used, the ash spraying device for preventing the air release valves of the double-hearth kiln is provided with two combustion air reversing valves (2) which are respectively arranged at the tops of a kiln hearth A and a kiln hearth B and connected with an exhaust gas pipe (3), the two combustion air reversing valves (2) are connected through combustion air branch pipes (4), and the combustion air branch pipes (4) are connected with combustion air release valves (11) and combustion air blowers through combustion air main pipes (1); the lower parts of the kiln chamber A and the kiln chamber B are connected through a cooling air branch pipe (10), and the cooling air branch pipe (10) is connected with a cooling air release valve (7) and a cooling fan through a cooling air main pipe (8); the method is characterized in that: an exhaust pipe (13) connected with the waste gas pipe (3) is arranged on the combustion air branch pipe (4), and an electric control valve (14) is arranged on the exhaust pipe (13); the exhaust port of the combustion air release valve (11) is connected with a dust removal filter (12), a plurality of rows of dust removal cloth bags (12-1) are arranged in the dust removal filter (12), a compressed air pulse device is arranged on each dust removal cloth bag (12-1), and the bottom of the dust removal filter (12) is connected with a star-shaped ash discharge valve (15) through an ash bucket;
the specific method comprises the following steps:
A. when the system cuts off the coal gas conveyed to the kiln, namely before the system enters the burnout time, the system controls to open the electric control valve (14), the gas in the kiln is conveyed to the dust remover through the exhaust pipe (13) and the waste gas pipe (3), and the pressure in the kiln is reduced to be below 10kpa before the kiln enters the reversing period; then opening the combustion-supporting air release valve (11), adjusting the opening speed of the combustion-supporting air release valve (11) to 8-10 seconds to realize slow release of gas in the kiln, and closing the electric control valve (14) after confirming that the combustion-supporting air release valve (11) is opened;
B. the compressed air pulse device blows the dust removal cloth bag (12-1) for 1 time/hour, and dust is conveyed into a finished product system through the star-shaped dust discharge valve (15);
C. opening the combustion air release valve (11) for 3 seconds and then opening the cooling air release valve (7) during the reversing period;
D. the granularity of the raw materials entering the kiln is controlled to be more than 80 percent of the weight of the raw materials of particles with the diameter of 40-80 mm;
E. the mode of "feeding during burning" is adopted, namely, through setting up the calcination period, the system carries out the mode of feeding in raw material to the heat accumulation thorax, through adjusting to reduce combustion air switching-over valve (2), discharge flashboard (9) and cooling air release valve (7) open, the action time of closing is 4 ~ 5 seconds in the switching-over period, kiln switching-over period time reduces to 35 ~ 40 seconds, realize coal gas, combustion air carry to kiln accumulative burning time extension 1960 ~ 2450 seconds in every day, the gas pressure value when making the kiln calcine reduces, reduce the spraying ash.
2. The method for preventing ash ejection of air relief valves of a dual-chamber kiln as defined in claim 1, wherein: setting the combustion air coefficient to be 1.0-1.1, observing the temperature curve of the optical pyrometer on the middle channel of the kiln, and controlling the difference between the highest temperature and the lowest temperature of the optical pyrometer to be less than or equal to 50 ℃ in the operation period; setting the coefficient of cooling air to be 0.65-0.75, and controlling the temperature of the ash-out finished product to be lower than 200 ℃.
3. The method for preventing ash ejection of air release valves of a dual-bore kiln as defined in claim 1 or 2, wherein: the calorific value of the fuel of the coal gas used for the kiln combustion is 7000kJ/m3The above.
4. The method for preventing ash ejection of air release valves of a dual-bore kiln as defined in claim 1 or 2, wherein: the electric control valve (14) adopts a hydraulic butterfly valve or a pneumatic butterfly valve controlled by a solenoid valve.
5. The method for preventing ash ejection of air relief valves of a dual-bore kiln as defined in claim 3, wherein: the electric control valve (14) adopts a hydraulic butterfly valve or a pneumatic butterfly valve controlled by a solenoid valve.
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| CN113959234A (en) * | 2021-09-30 | 2022-01-21 | 广西柳州钢铁集团有限公司 | Method for judging air leakage of combustion-supporting reversing valve of double-hearth kiln |
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| CN114353505A (en) * | 2021-12-15 | 2022-04-15 | 广西柳州钢铁集团有限公司 | Environment-friendly efficient double-chamber kiln |
| CN114524628A (en) * | 2022-02-28 | 2022-05-24 | 中冶长天国际工程有限责任公司 | Double-hearth lime kiln system without dust leakage and pressure relief method |
| CN114685067A (en) * | 2022-03-28 | 2022-07-01 | 广西柳钢新材料科技有限公司 | Rapid and stable cooling and emptying method for double-hearth kiln |
| CN116535113A (en) * | 2023-05-23 | 2023-08-04 | 广西柳钢新材料科技有限公司 | Method for preventing dust deposition in middle channel of double-chamber kiln |
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| CN113932601A (en) * | 2021-09-01 | 2022-01-14 | 广西柳钢新材料科技有限公司 | Double-chamber kiln cooling air control distribution method |
| CN113959234A (en) * | 2021-09-30 | 2022-01-21 | 广西柳州钢铁集团有限公司 | Method for judging air leakage of combustion-supporting reversing valve of double-hearth kiln |
| CN113959234B (en) * | 2021-09-30 | 2023-09-29 | 广西柳州钢铁集团有限公司 | Method for judging air leakage of combustion-supporting reversing valve of double-chamber kiln |
| CN114111346A (en) * | 2021-11-30 | 2022-03-01 | 广东韶钢松山股份有限公司 | Fire-blending temperature-raising quick reproduction method after double-chamber kiln overhaul |
| CN114111346B (en) * | 2021-11-30 | 2023-12-01 | 广东韶钢松山股份有限公司 | Method for quickly reproducing double-hearth kiln after overhauling by adding fire and raising temperature |
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| CN114524628A (en) * | 2022-02-28 | 2022-05-24 | 中冶长天国际工程有限责任公司 | Double-hearth lime kiln system without dust leakage and pressure relief method |
| CN114524628B (en) * | 2022-02-28 | 2023-10-03 | 中冶长天国际工程有限责任公司 | Double-chamber lime kiln system without dust leakage and pressure relief method |
| CN114685067A (en) * | 2022-03-28 | 2022-07-01 | 广西柳钢新材料科技有限公司 | Rapid and stable cooling and emptying method for double-hearth kiln |
| CN116535113A (en) * | 2023-05-23 | 2023-08-04 | 广西柳钢新材料科技有限公司 | Method for preventing dust deposition in middle channel of double-chamber kiln |
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