CN111943531A - Kiln drying method of double-chamber lime shaft kiln - Google Patents
Kiln drying method of double-chamber lime shaft kiln Download PDFInfo
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- CN111943531A CN111943531A CN202010861537.2A CN202010861537A CN111943531A CN 111943531 A CN111943531 A CN 111943531A CN 202010861537 A CN202010861537 A CN 202010861537A CN 111943531 A CN111943531 A CN 111943531A
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- 235000008733 Citrus aurantifolia Nutrition 0.000 title claims abstract description 38
- 235000011941 Tilia x europaea Nutrition 0.000 title claims abstract description 38
- 239000004571 lime Substances 0.000 title claims abstract description 38
- 238000001035 drying Methods 0.000 title claims abstract description 37
- 238000004321 preservation Methods 0.000 claims abstract description 95
- 238000010438 heat treatment Methods 0.000 claims abstract description 42
- 238000000034 method Methods 0.000 claims abstract description 10
- 238000001816 cooling Methods 0.000 claims description 48
- 238000002485 combustion reaction Methods 0.000 claims description 15
- 238000007599 discharging Methods 0.000 claims description 6
- 239000000463 material Substances 0.000 claims description 5
- 239000011449 brick Substances 0.000 abstract description 25
- 238000005336 cracking Methods 0.000 abstract description 15
- XLYOFNOQVPJJNP-UHFFFAOYSA-N water Substances O XLYOFNOQVPJJNP-UHFFFAOYSA-N 0.000 description 31
- 238000004519 manufacturing process Methods 0.000 description 14
- 230000000630 rising effect Effects 0.000 description 13
- 239000003034 coal gas Substances 0.000 description 11
- 239000011819 refractory material Substances 0.000 description 10
- 239000013078 crystal Substances 0.000 description 8
- 230000009286 beneficial effect Effects 0.000 description 6
- 238000001704 evaporation Methods 0.000 description 5
- 230000008020 evaporation Effects 0.000 description 5
- 150000003839 salts Chemical class 0.000 description 5
- 239000000126 substance Substances 0.000 description 5
- 238000011160 research Methods 0.000 description 4
- 238000009423 ventilation Methods 0.000 description 4
- 239000000446 fuel Substances 0.000 description 3
- 238000011534 incubation Methods 0.000 description 3
- 230000003287 optical effect Effects 0.000 description 3
- 239000007921 spray Substances 0.000 description 3
- 230000018044 dehydration Effects 0.000 description 2
- 238000006297 dehydration reaction Methods 0.000 description 2
- RNFJDJUURJAICM-UHFFFAOYSA-N 2,2,4,4,6,6-hexaphenoxy-1,3,5-triaza-2$l^{5},4$l^{5},6$l^{5}-triphosphacyclohexa-1,3,5-triene Chemical compound N=1P(OC=2C=CC=CC=2)(OC=2C=CC=CC=2)=NP(OC=2C=CC=CC=2)(OC=2C=CC=CC=2)=NP=1(OC=1C=CC=CC=1)OC1=CC=CC=C1 RNFJDJUURJAICM-UHFFFAOYSA-N 0.000 description 1
- 238000009825 accumulation Methods 0.000 description 1
- 239000003153 chemical reaction reagent Substances 0.000 description 1
- 230000007547 defect Effects 0.000 description 1
- 230000000694 effects Effects 0.000 description 1
- 238000005265 energy consumption Methods 0.000 description 1
- 238000005516 engineering process Methods 0.000 description 1
- 230000002349 favourable effect Effects 0.000 description 1
- 239000003063 flame retardant Substances 0.000 description 1
- 239000012530 fluid Substances 0.000 description 1
- 238000009413 insulation Methods 0.000 description 1
- 239000007788 liquid Substances 0.000 description 1
- 239000008239 natural water Substances 0.000 description 1
- 239000000843 powder Substances 0.000 description 1
- 238000002360 preparation method Methods 0.000 description 1
- 230000002035 prolonged effect Effects 0.000 description 1
- 230000033764 rhythmic process Effects 0.000 description 1
- 239000004449 solid propellant Substances 0.000 description 1
- 238000010792 warming Methods 0.000 description 1
Classifications
-
- 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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- Chemical & Material Sciences (AREA)
- Engineering & Computer Science (AREA)
- Ceramic Engineering (AREA)
- Physics & Mathematics (AREA)
- Thermal Sciences (AREA)
- Materials Engineering (AREA)
- Structural Engineering (AREA)
- Organic Chemistry (AREA)
- Muffle Furnaces And Rotary Kilns (AREA)
Abstract
The application provides a kiln drying method of a double-chamber lime shaft kiln, and belongs to the technical field of double-chamber lime shaft kilns. The kiln drying method comprises a first heating stage, a first heat preservation stage, a second heating stage, a second heat preservation stage, a third heating stage, a third heat preservation stage, a fourth heating stage and a fourth heat preservation stage which are sequentially carried out on a direct connection channel of the double-hearth lime shaft kiln. Wherein the heating rate of each heating stage is less than or equal to 15 ℃/h; the heat preservation temperature of the first heat preservation stage is 142.5-157.5 ℃, the heat preservation temperature of the second heat preservation stage is 285-315 ℃, the heat preservation temperature of the third heat preservation stage is 570-630 ℃, and the heat preservation temperature of the fourth heat preservation stage is 855-945 ℃. The method can effectively avoid the problems of cracking of the bricks, damage to the special-shaped bricks of the direct-connection channel arch, cracking of the furnace wall and the like.
Description
Technical Field
The application relates to the technical field of double-chamber lime shaft kilns, in particular to a kiln drying method of a double-chamber lime shaft kiln.
Background
The parallel-flow heat accumulating type double-chamber lime shaft kiln can produce high-quality active lime by adopting liquid fuel, gas fuel, powder solid fuel and other fluid fuels, and the heat energy consumption of the parallel-flow heat accumulating type double-chamber lime shaft kiln is the lowest in all lime kiln furnaces, so that the parallel-flow heat accumulating type double-chamber lime shaft kiln can be widely applied to the metallurgical lime industry. When a newly built masonry lining is built or kiln lining bricks are replaced and overhaul is carried out, the stage of kiln drying after ignition before production needs to be carried out, and the service life and the service cycle of kiln refractory are usually determined to a great extent by the control of kiln drying temperature rise and the quality of kiln drying effect.
The furnace baking method in the prior art is easy to cause the cracking of bricks to influence the service life of kiln lining refractory materials and the kiln clothing cycle; the service life of the special-shaped bricks of the direct-connection channel arch is easy to damage and is greatly shortened; and the furnace wall is easy to crack, the heat insulation performance of the production and operation of the kiln after the kiln is dried is easy to influence, and the airflow trend of the kiln is easy to influence.
Disclosure of Invention
The application aims to provide a kiln drying method of a double-chamber lime shaft kiln, which can effectively solve the problems.
The embodiment of the application is realized as follows:
in a first aspect, an embodiment of the present application provides a kiln drying method for a double-bore lime shaft kiln, including a first temperature rise stage, a first heat preservation stage, a second temperature rise stage, a second heat preservation stage, a third temperature rise stage, a third heat preservation stage, a fourth temperature rise stage, and a fourth heat preservation stage that are sequentially performed on a direct connection channel of the double-bore lime shaft kiln.
Wherein the heating rate of each heating stage is less than or equal to 15 ℃/h; the heat preservation temperature of the first heat preservation stage is 142.5-157.5 ℃, the heat preservation temperature of the second heat preservation stage is 285-315 ℃, the heat preservation temperature of the third heat preservation stage is 570-630 ℃, and the heat preservation temperature of the fourth heat preservation stage is 855-945 ℃.
The baking oven technology method commonly adopted in the industry at present is as follows: heating to 600 ℃ at the heating rate of 25 ℃/h, and keeping the temperature for 24 h; then heating to 900 ℃ at the heating rate of 12.5 ℃/h, preserving the heat for 8-16 h, and then switching to a normal production state.
It was found that in the current kiln process, the kiln temperature is not increased until 600 ℃, because the temperature increase rate is fast and there is no heat preservation process: the arch door special-shaped bricks of the connecting channel are easily damaged; meanwhile, the method is not beneficial to the full volatilization of water, the cracking of the brick is easily caused, and the furnace wall is easy to crack.
Research also finds that when the kiln is dried in the direct-connected channel of the double-chamber lime shaft kiln, after the temperature of the kiln in the direct-connected channel exceeds 100 ℃, the kiln lining is heated and then the moisture begins to volatilize; when the temperature of the kiln in the direct connection channel reaches about 150 ℃, the temperature of the kiln liner is close to the temperature of water evaporation, and water can be fully discharged; when the temperature of the kiln in the direct connection channel reaches about 300 ℃, hydrate of refractory materials such as kiln lining bricks, castable and the like can be effectively removed.
The kiln drying method of the double-chamber lime shaft kiln provided by the embodiment of the application has the beneficial effects that:
the temperature rise in the first temperature rise stage is carried out at the speed of less than or equal to 15 ℃/h, the slow temperature rise process is beneficial to slowly and uniformly discharging a large amount of natural moisture and adsorbed moisture of the new masonry, and is beneficial to avoiding deformation, cracking or microcracking. And then, carrying out a first heat preservation stage at the heat preservation temperature of 142.5-157.5 ℃, wherein the temperature of the kiln liner is close to the temperature of water evaporation under the temperature condition, so that moisture can be fully discharged, and the natural moisture of refractory materials such as kiln liner bricks, castable materials and the like is fully discharged, thereby being beneficial to improving the drying strength.
After the first heat preservation stage, because the moisture is fully discharged, the water vapor in the double-hearth lime shaft kiln is heavier at the moment, the double-hearth lime shaft kiln enters a second heat preservation stage at the moment, and because the heat preservation stage can increase the amount of the introduced gas for combustion, the air flow in the direct connection channel is accelerated, the evaporated water vapor can be quickly taken away, the accelerated drying is facilitated, and the mechanical strength of a new masonry body, particularly a castable, is improved; the temperature is slowly raised in the first temperature raising stage at the speed of less than or equal to 15 ℃/h, the temperature raising time is long, and the evaporated water vapor is favorably and fully taken away. And then, a second heat preservation stage is carried out at the heat preservation temperature of 285-315 ℃, so that hydrate is fully dehydrated, the new masonry, especially the castable, has higher strength, and the expansion and cracking of a blank are effectively avoided.
In the third heat preservation stage with the heat preservation temperature of 570-630 ℃, the chemical crystal water, the combined water and partial salt of the new masonry can be fully decomposed and crystal transformed, and the strength of the refractory material of the new masonry is further improved.
And in the fourth heat preservation stage with the heat preservation temperature of 855-945 ℃, the new masonry is maintained in a stable state, so that the new masonry has better high-temperature service performance and is prepared for further transfer to production operation.
In the embodiment of the application, the heat preservation control is carried out through a temperature node of 142.5-157.5 ℃ to ensure that the moisture is fully discharged; the temperature nodes at 285-315 ℃ and 570-630 ℃ are used for heat preservation control, so that the strength and the high temperature resistance of the masonry material in the kiln are improved; the stability and the high-temperature service performance are improved through a 855-945 ℃ temperature node. Through the full baking of each temperature node, the temperature is slowly raised at the speed of less than or equal to 15 ℃/h in each temperature raising stage for matching, and the problems of cracking of bricks, damage to special-shaped bricks of the direct-connection channel arch doors, cracking of furnace walls and the like are effectively avoided.
Detailed Description
In order to make the objects, technical solutions and advantages of the embodiments of the present application clearer, the technical solutions of the embodiments of the present application will be clearly and completely described below. The examples, in which specific conditions are not specified, were conducted under conventional conditions or conditions recommended by the manufacturer. The reagents or instruments used are not indicated by the manufacturer, and are all conventional products available commercially.
It should be noted that "and/or" in the present application, such as "scheme a and/or scheme B" means that the three modes of scheme a alone, scheme B alone, scheme a plus scheme B may be used.
The method of drying the double-chamber lime shaft kiln according to the embodiment of the present application will be specifically described below.
The embodiment of the application provides a kiln drying method of a double-hearth lime shaft kiln, which comprises a first heating stage, a first heat preservation stage, a second heating stage, a second heat preservation stage, a third heating stage, a third heat preservation stage, a fourth heating stage and a fourth heat preservation stage which are sequentially carried out on a direct connection channel of the double-hearth lime shaft kiln.
It can be understood that, in the embodiment of the present application, in the temperature raising stage, as the heat demand is increased, the amount of the gas to be combusted is increased, and the amount of the introduced gas is increased; in the heat preservation stage, as the heat demand is unchanged, the amount of the coal gas required to be combusted is unchanged, and the amount of the introduced coal gas is basically unchanged.
In the prior art, when a kiln is started to be dried, firewood is usually put into a direct connection channel through a fire poking hole for ignition, after the firewood is burnt vigorously, a gas valve, a combustion-supporting gas valve and a cooling air valve at a burner are opened, and then the burner is ignited through the firewood to realize ignition. In the ignition mode, a fireman is required to throw firewood periodically through the fire poking holes at the initial stage of the kiln drying; and when the flame-retardant plastic is put into the fire poking hole, the flame easily escapes from the fire poking hole, so that the safety risk of being burnt is caused.
In some possible embodiments, when the kiln is started to be dried, a gas valve, a combustion-supporting gas valve and a cooling air valve at the burner are opened, and then an ignition gun extends into the lower portion of the burner in the direct-connection channel through a fire poking hole to ignite the burner, so that ignition is achieved.
As the research finds that when the kiln is dried in the direct-connected channel of the double-chamber lime shaft kiln, the temperature of the kiln in the direct-connected channel exceeds 100 ℃, the water content begins to volatilize after the kiln lining is heated; when the temperature of the kiln in the direct connection channel reaches about 150 ℃, the temperature of the kiln liner is close to the temperature of water evaporation, and water can be fully discharged.
In the embodiment of the application, the temperature rise rate of the first temperature rise stage is less than or equal to 15 ℃/h, the slow temperature rise process is beneficial to slowly and uniformly discharging a large amount of natural moisture and adsorbed moisture of the new masonry, and deformation, cracking or microcracking is favorably avoided. The heat preservation temperature of the first heat preservation stage is 142.5-157.5 ℃, and because the temperature of the kiln lining is close to the temperature of water evaporation under the temperature condition, water can be fully discharged, so that natural water of refractory materials such as kiln lining bricks and castable materials can be fully discharged, and the drying strength can be improved.
As a result of research, when the temperature of the kiln in the direct connection channel reaches about 300 ℃, hydrate of refractory materials such as kiln lining bricks, castable and the like can be effectively removed. After first heat preservation stage, because moisture is fully arranged outward, the steam in the double-chamber lime shaft kiln is heavier this moment, gets into the second heat preservation stage this moment, because the heat preservation stage can increase the coal gas volume that lets in and carry out the burning for the air current accelerates in the direct connection passageway, can take away the steam of evaporation fast, is favorable to drying with higher speed, has improved the mechanical strength of new brickwork especially pouring material.
In the embodiment of the application, the temperature rise rate of the second temperature rise stage is less than or equal to 15 ℃/h, and the temperature rise time is long, so that evaporated water vapor can be fully taken away. The heat preservation temperature of the second heat preservation stage is 285-315 ℃, the hydrate is fully dehydrated, the new masonry, particularly the castable, obtains high strength, and the expansion and cracking of the green body are effectively avoided.
In the embodiment of the application, the heat preservation temperature of the third heat preservation stage is 570-630 ℃, heat preservation is carried out under the temperature condition, chemical crystal water, binding water and partial salt of the new masonry can be fully decomposed and crystal transformed, and the strength of the refractory material of the new masonry is further improved. The heat preservation temperature of the fourth heat preservation stage is 855-945 ℃, so that the new masonry is maintained in a stable state, the new masonry has good high-temperature service performance, and preparation is made for further transfer to production operation.
According to the kiln drying method of the double-chamber lime shaft kiln, the heating rate of each heating stage is not more than 15 ℃/h, the heating is slowly heated at a speed not more than 15 ℃/h in each heating stage to be matched through fully baking each temperature node, and the problems of cracking of bricks, damage to arch special-shaped bricks of direct-connection channel, cracking of furnace walls and the like are effectively avoided.
It is understood that in the embodiments of the present application, the kiln drying process is not limited to only performing the four temperature-raising stages and the four temperature-keeping stages, and the temperature-keeping stage and the temperature-raising stage may be added before or after any one temperature-keeping stage according to the requirement.
Regarding the first warming phase:
illustratively, the ramp rate is 12-13 ℃/h, such as but not limited to, any one of or a range between any two of 12 ℃/h, 12.3 ℃/h, 12.5 ℃/h, 12.7 ℃/h, and 13 ℃/h. The temperature rise time is 11-13 h, or 11.5-12.5 h, such as 12 h. Under the condition of the temperature rising rate, the temperature is ensured to rise smoothly and stably, and the moisture is discharged uniformly.
Optionally, the gas flow is 250-350 m3H, for example but not limited to 250m3/h、280m3/h、300m3/h、320m3H and 350m3Any one of/h or a range between any two. Under the condition of the coal gas flow, the requirement of the heating rate of the first heating stage can be well met.
Optionally, the flow of combustion-supporting air is 1000-2000 m3H, for example but not limited to 1000m3/h、1200m3/h、1500m3/h、1800m3H and 2000m3Any one of/h or a range between any two. Under the condition of the flow of the combustion-supporting air, the coal gas can be fully combusted.
Optionally, the flow rate of the cooling air is 1500-2500 m3H, for example but not limited to 1500m3/h、1800m3/h、2000m3/h、2200m3H and 2500m3Any one of/h or a range between any two. Under this cooling air flow condition, can carry the inside of two kiln barrels with the heat in the direct-connection passageway effectively, avoid the direct-connection passageway overheated, can effectively carry out the even heating to building stones and kiln chamber lining brick in the kiln barrel simultaneously.
Furthermore, the rotating speed of the fan of the combustion-supporting air is 300-350 r/min, and the rotating speed of the fan of the cooling air is 300-350 r/min, such as 300r/min, 310r/min, 320r/min, 330r/min, 340r/min or 350r/min, and is matched with the ventilation volume of the first temperature rise stage, so that the temperature rise rate is well controlled.
Furthermore, as researches show that when moisture volatilizes at the temperature of 100-150 ℃, excessive water vapor accumulation easily causes cracking of kiln bricks, in the kiln drying stage, the temperature and the drainage condition of the kiln body exhaust holes are observed every 3-5 hours, for example, the temperature and the drainage condition of the kiln body exhaust holes are observed every 4 hours, and when the temperature deviates from the target, the temperature is adjusted.
Illustratively, when the exhaust steam of the exhaust hole of the kiln body is less or has no exhaust steam, the temperature of the kiln is increased by about 5 ℃, for example, by 4-6 ℃ or 5 ℃, so as to properly and effectively accelerate the water drainage speed; if the amount of the water discharged from the exhaust hole of the kiln body is too large, the temperature of the kiln needs to be reduced by about 5 ℃, for example, by 4 to 6 ℃ or 5 ℃, so as to properly and effectively reduce the water discharge speed. Wherein, the condition that no water drops are discharged from the vent holes with the numbers of 1/2-2/3 is observed; the excessive amount of the discharged water vapor means that the phenomenon that each exhaust hole drops more water and discharges less vapor at the initial stage is observed.
Regarding the first soak phase:
exemplary holding temperatures are 144 to 156 ℃, or 145.5 to 154.5 ℃, or 147 to 153 ℃, or 148.5 to 151.5 ℃, for example 150 ℃. If the heat preservation temperature is too low, the water cannot be effectively volatilized and discharged; if the heat preservation temperature is too high, the uniformity of moisture discharge can be influenced, and the moisture discharge is too fast, so that the kiln brick is easy to crack.
It can be understood that the holding temperature in the holding stage is difficult to keep absolutely constant during the kiln due to the influence of gas flow fluctuation and the like. In the embodiment of the present application, the holding temperature in each holding stage is a target temperature for holding. The conditions in the kiln need to be observed during kiln drying, and illustratively, the highest temperature measured by a thermocouple in the direct-connection channel is taken as the actual temperature, and when the actual temperature deviates from the target heat preservation temperature, the actual temperature is made to be matched with the target heat preservation temperature by adjusting the gas flow, the rotating speed of a fan of combustion-supporting air, the rotating speed of a fan of cooling air and the like.
Optionally, the heat preservation time of the first heat preservation stage is 23-25 hours, or 23.5-24.5 hours, or 23.8-24.2 hours, for example, 24 hours, so as to ensure that the moisture is sufficiently discharged.
Regarding the second temperature raising stage:
illustratively, the ramp rate is 12-13 ℃/h, such as but not limited to, any one of or a range between any two of 12 ℃/h, 12.3 ℃/h, 12.5 ℃/h, 12.7 ℃/h, and 13 ℃/h. The temperature rise time is 11-13 h, or 11.5-12.5 h, such as 12 h. Under the condition of the temperature rising rate, the temperature is ensured to rise smoothly and stably.
Optionally, the gas flow is 500-600 m3H, for example but not limited to 500m3/h、530m3/h、550m3/h、580m3H and 600m3Any one of/h or a range between any two. Under the condition of the gas flow, the requirement of the temperature rise rate in the second temperature rise stage can be well met.
Optionally, the flow of combustion-supporting air is 1000-2000 m3H, for example but not limited to 1000m3/h、1200m3/h、1500m3/h、1800m3H and 2000m3Any one of/h or a range between any two. Under the condition of the flow of the combustion-supporting air, the coal gas can be fully combusted.
Optionally, the flow rate of the cooling air is 1500-2500 m3H, for example but not limited to 1500m3/h、1800m3/h、2000m3/h、2200m3H and 2500m3Any one of/h or a range between any two. Under this cooling air flow condition, can carry the inside of two kiln barrels with the heat in the direct-connection passageway effectively, avoid the direct-connection passageway overheated, can effectively carry out the even heating to building stones and kiln chamber lining brick in the kiln barrel simultaneously.
Furthermore, the rotating speed of the fan of the combustion-supporting air is 350-450 r/min, the rotating speed of the fan of the cooling air is 350-450 r/min, such as 350r/min, 370r/min, 390r/min, 410r/min, 430r/min or 450r/min, and the temperature rise rate is guaranteed to be well controlled by matching with the ventilation volume of the second temperature rise stage.
Regarding the second incubation period:
illustratively, the holding temperature is 288-312 ℃, 291-309 ℃, 294-306 ℃, 297-303 ℃, such as 300 ℃. If the heat preservation temperature is too low, hydrate cannot be effectively dehydrated; if the holding temperature is too high, dehydration is too fast, and cracks are easily generated in the kiln brick.
Optionally, the heat preservation time of the second heat preservation stage is 23-25 h, or 23.5-24.5 h, or 23.8-24.2 h, for example 24h, so as to achieve sufficient dehydration of the hydrate.
Regarding the third temperature raising stage:
illustratively, the ramp rate is 12-14 ℃/h, or 12-13 ℃/h, such as but not limited to any one of or a range between any two of 12 ℃/h, 12.5 ℃/h, 13 ℃/h, 13.5 ℃/h, and 14 ℃/h. The temperature rise time is 21-25 h, or 22-24 h, such as 23 h. Under the condition of the temperature rising rate, the temperature is ensured to rise smoothly and stably.
Optionally, the gas flow is 600-900 m3H, for example but not limited to 600m3/h、700m3/h、800m3H and 900m3Any one of/h or a range between any two. Under the condition of the gas flow, the requirement of the heating rate of the third heating stage can be better met.
Optionally, the flow of combustion-supporting air is 2000-3000 m3H, for example but not limited to 2000m3/h、2200m3/h、2500m3/h、2800m3H and 3000m3Any one of/h or a range between any two. Under the condition of the flow of the combustion-supporting air, the coal gas can be fully combusted.
Optionally, the flow rate of the cooling air is 2500-3500 m3H, for example but not limited to 2500m3/h、2800m3/h、3000m3/h、3200m3H and 3500m3Any one of/h or a range between any two. Under this cooling air flow condition, can carry the inside of two kiln barrels with the heat in the direct-connection passageway effectively, avoid the direct-connection passageway overheated, can effectively carry out the even heating to building stones and kiln chamber lining brick in the kiln barrel simultaneously.
Furthermore, the rotating speed of the fan of the combustion-supporting air is 400-600 r/min, the rotating speed of the fan of the cooling air is 400-600 r/min, such as 400r/min, 450r/min, 500r/min, 550r/min or 600r/min, and the temperature rise rate is well controlled by matching with the ventilation volume of the third temperature rise stage.
Regarding the third incubation period:
exemplary holding temperatures are 576-624 deg.C, 582-618 deg.C, 588-612 deg.C, 594-606 deg.C, such as 600 deg.C. If the heat preservation temperature is too low, the chemical crystal water, the combined water and partial salt of the new masonry can not be effectively decomposed and transformed; if the holding temperature is too high, the chemical crystal water, the binding water and part of the salt are decomposed and discharged too quickly, which easily causes the strength reduction of the kiln brick.
Optionally, the heat preservation time of the third heat preservation stage is 47-49 h, or 47.5-48.5 h, or 47.8-48.2 h, for example 48h, so as to ensure that the chemical crystal water, the binding water and part of the salt of the new brickwork are fully decomposed and crystal transformed.
Regarding the fourth temperature raising stage:
illustratively, the ramp rate is 12-14 ℃/h, or 12-13 ℃/h, such as but not limited to any one of or a range between any two of 12 ℃/h, 12.5 ℃/h, 13 ℃/h, 13.5 ℃/h, and 14 ℃/h. The temperature rise time is 21-25 h, or 22-24 h, such as 23 h. Under the condition of the temperature rising rate, the temperature is ensured to rise smoothly and stably.
Optionally, the gas flow is 1000-1500 m3H, for example but not limited to 1000m3/h、1100m3/h、1200m3/h、1300m3/h、1400m3H and 350m3Any one of/h or a range between any two. Under the condition of the gas flow, the requirement of the heating rate of the fourth heating stage can be well met.
Optionally, the flow of combustion-supporting air is 3500-5000 m3H, for example but not limited to 3500m3/h、4000m3/h、4500m3H and 5000m3Any one of/h or a range between any two. Under the condition of the flow of the combustion-supporting air, the coal gas can be fully combusted.
Optionally, the flow of the cooling air is 6500-7500 m3H, for example but not limited to 6500m3/h、6800m3/h、7000m3/h、7300m3H and 7500m3Any one of/h or a range between any two. The cooling air flow rate conditionUnder, can carry the inside of two kiln barrels with the heat in the direct-connection passageway effectively, avoid the direct-connection passageway overheated, can effectively carry out the even heating to building stones and kiln chamber lining brick in the kiln barrel simultaneously.
Furthermore, the rotating speed of the fan of the combustion-supporting air is 500-600 r/min, the rotating speed of the fan of the cooling air is 3500-600 r/min, such as 500r/min, 520r/min, 540r/min, 560r/min, 580r/min or 600r/min, and the temperature rise rate is well controlled by matching with the ventilation volume of the fourth temperature rise stage.
Regarding the fourth incubation period:
exemplary holding temperatures are 864-936 ℃, 873-927 ℃, 882-918 ℃, or 891-909 ℃, such as 900 ℃. If the heat preservation temperature is too low or too high, the heat preservation temperature cannot be well matched with the subsequent production.
Optionally, the heat preservation time of the fourth heat preservation stage is 47-49 hours, or 47.5-48.5 hours, or 47.8-48.2 hours, for example, 48 hours, so as to ensure that the interior of the kiln cylinder reaches a stable state, and the kiln cylinder has good high-temperature use performance.
In order to ensure the output of the double-chamber lime shaft kiln, the production is usually accompanied in the kiln drying process.
In some exemplary embodiments, prior to the fourth ramp-up phase, the output of the double-bore lime shaft kiln is 40t/d, discharging 1 batch per hour; optionally, the combustion period before discharging is 3520s, and the reversing time is 80 s. Before the fourth temperature rise stage, production is carried out through a low-yield rhythm mode, and meanwhile, a proper combustion period and a proper reversing parameter are controlled, so that the kiln lining refractory material can be fully baked while production is guaranteed.
In some exemplary embodiments, starting from the fourth ramp phase, the double-chamber lime shaft kiln has a throughput of 20t/d and discharges 1 batch per hour; optionally, the combustion period before the commutation is 1720s, and the commutation time is 80 s. Furthermore, from the fourth temperature rise stage, the yield is improved, and meanwhile, the proper combustion period and the proper reversing parameters are controlled, so that the requirements of the rotary production mode after the kiln is dried can be well met while the kiln lining refractory material is fully baked.
Further, the discharging is set to 10-20 times/batch, for example, 10 times/batch, 15 times/batch or 20 times/batch. The number of the operation is the number of the operation lot, and the number of the operation times is the number of the operation frequency of the operation lot.
The features and properties of the present application are described in further detail below with reference to examples.
Example 1
A kiln drying method of a double-chamber lime shaft kiln comprises the following steps:
s1, a first temperature rise stage:
setting the output to be 20t/d, moving the kiln to discharge 1 batch per hour, and setting the discharge to be 10 times per batch; the combustion period before commutation was 3520s, and the commutation time was 80 s.
And opening the gas valve, the combustion-supporting gas valve and the cooling air valve, igniting the burner by adopting an ignition gun, and adjusting the opening of each valve to increase by 5%. And controlling the gas flow, the combustion-supporting air flow, the cooling air flow, the rotating speed of a fan of the combustion-supporting air and the rotating speed of a fan of the cooling air, so that the temperature in the direct connection channel is increased to 150 ℃ at the temperature increase rate of 12 ℃/h. Wherein, the observation and the adjustment of the temperature and the drainage condition of the kiln body exhaust holes are carried out every 4 hours.
S2, a first heat preservation stage:
keeping the temperature for 24h under the condition that the temperature of the direct connection channel is 150 ℃.
S3, a second temperature rising stage:
the opening of each valve is adjusted and increased by 6 percent, and the gas flow, the combustion-supporting air flow, the cooling air flow, the rotating speed of a fan of the combustion-supporting air and the rotating speed of the fan of the cooling air are controlled, so that the temperature in the direct connection channel is increased to 300 ℃ at the heating rate of 13 ℃/h.
S4, a second heat preservation stage:
keeping the temperature for 24h under the condition that the temperature of the direct connection channel is 300 ℃.
S5, a third temperature rising stage:
the opening of each valve is adjusted and increased by 6 percent, and the gas flow, the combustion-supporting air flow, the cooling air flow, the rotating speed of a fan of the combustion-supporting air and the rotating speed of the fan of the cooling air are controlled, so that the temperature in the direct connection channel is increased to 600 ℃ at the heating rate of 12 ℃/h.
S6, a third heat preservation stage:
keeping the temperature for 48h under the condition that the temperature of the direct connection channel is 600 ℃.
S7, a fourth temperature rising stage:
the production was adjusted to 40t/d, the combustion period before the reversal was 1720s and the reversal time was 80 s.
The opening of each valve was adjusted to increase by 8%. And controlling the gas flow, the combustion-supporting air flow, the cooling air flow, the rotating speed of a fan of the combustion-supporting air and the rotating speed of a fan of the cooling air, so that the temperature in the direct connection channel is increased to 900 ℃ at a heating rate of 14 ℃/h.
S8, a fourth heat preservation stage:
keeping the temperature for 48h under the condition that the temperature of the direct connection channel is 900 ℃.
S9, stopping the kiln, detaching the ignition burner, installing the optical pyrometer, and turning to the spray gun to introduce gas for ignition.
Example 2
A kiln drying method of a double-chamber lime shaft kiln comprises the following steps:
s1, a first temperature rise stage:
setting the output to be 20t/d, moving the kiln to discharge 1 batch per hour, and setting the discharge to be 15 times per batch; the combustion period before commutation was 3520s, and the commutation time was 80 s.
And opening the gas valve, the combustion-supporting gas valve and the cooling air valve, igniting the burner by adopting an ignition gun, and adjusting the opening of each valve to increase by 5%. And controlling the gas flow, the combustion-supporting air flow, the cooling air flow, the rotating speed of a fan of the combustion-supporting air and the rotating speed of the fan of the cooling air, so that the temperature in the direct connection channel is increased to 150 ℃ at the temperature increase rate of 12.5 ℃/h. Wherein, the observation and the adjustment of the temperature and the drainage condition of the kiln body exhaust holes are carried out every 4 hours.
S2, a first heat preservation stage:
keeping the temperature for 24h under the condition that the temperature of the direct connection channel is 150 ℃.
S3, a second temperature rising stage:
the opening of each valve is adjusted and increased by 8 percent, and the gas flow, the combustion-supporting air flow, the cooling air flow, the rotating speed of a fan of the combustion-supporting air and the rotating speed of the fan of the cooling air are controlled, so that the temperature in the direct connection channel is increased to 300 ℃ at the temperature increase rate of 12.5 ℃/h.
S4, a second heat preservation stage:
keeping the temperature for 24h under the condition that the temperature of the direct connection channel is 300 ℃.
S5, a third temperature rising stage:
the opening of each valve is adjusted and increased by 8 percent, and the gas flow, the combustion-supporting air flow, the cooling air flow, the rotating speed of a fan of the combustion-supporting air and the rotating speed of the fan of the cooling air are controlled, so that the temperature in the direct connection channel is increased to 600 ℃ at the temperature increase rate of 12.5 ℃/h.
S6, a third heat preservation stage:
keeping the temperature for 48h under the condition that the temperature of the direct connection channel is 600 ℃.
S7, a fourth temperature rising stage:
the production was adjusted to 40t/d, the combustion period before the reversal was 1720s and the reversal time was 80 s.
The opening of each valve was adjusted to increase by 8%. And controlling the gas flow, the combustion-supporting air flow, the cooling air flow, the rotating speed of a fan of the combustion-supporting air and the rotating speed of the fan of the cooling air, so that the temperature in the direct connection channel is increased to 900 ℃ at the temperature increase rate of 12.5 ℃/h.
S8, a fourth heat preservation stage:
keeping the temperature for 48h under the condition that the temperature of the direct connection channel is 900 ℃.
S9, stopping the kiln, detaching the ignition burner, installing the optical pyrometer, and turning to the spray gun to introduce gas for ignition.
Example 3
A kiln drying method of a double-chamber lime shaft kiln comprises the following steps:
s1, a first temperature rise stage:
setting the output to be 20t/d, moving the kiln to discharge 1 batch per hour, and setting the discharge to be 20 times/batch; the combustion period before commutation was 3520s, and the commutation time was 80 s.
And opening the gas valve, the combustion-supporting gas valve and the cooling air valve, igniting the burner by adopting an ignition gun, and adjusting the opening of each valve to increase by 5%. And controlling the gas flow, the combustion-supporting air flow, the cooling air flow, the rotating speed of a fan of the combustion-supporting air and the rotating speed of the fan of the cooling air, so that the temperature in the direct connection channel is increased to 150 ℃ at a heating rate of 13 ℃/h. Wherein, the observation and the adjustment of the temperature and the drainage condition of the kiln body exhaust holes are carried out every 4 hours.
S2, a first heat preservation stage:
keeping the temperature for 24h under the condition that the temperature of the direct connection channel is 150 ℃.
S3, a second temperature rising stage:
the opening of each valve is adjusted and increased by 8 percent, and the gas flow, the combustion-supporting air flow, the cooling air flow, the rotating speed of a fan of the combustion-supporting air and the rotating speed of the fan of the cooling air are controlled, so that the temperature in the direct connection channel is increased to 300 ℃ at the heating rate of 12 ℃/h.
S4, a second heat preservation stage:
keeping the temperature for 24h under the condition that the temperature of the direct connection channel is 300 ℃.
S5, a third temperature rising stage:
the opening of each valve is adjusted and increased by 10 percent, and the gas flow, the combustion-supporting air flow, the cooling air flow, the rotating speed of a fan of the combustion-supporting air and the rotating speed of the fan of the cooling air are controlled, so that the temperature in the direct connection channel is increased to 600 ℃ at the heating rate of 14 ℃/h.
S6, a third heat preservation stage:
keeping the temperature for 48h under the condition that the temperature of the direct connection channel is 600 ℃.
S7, a fourth temperature rising stage:
the production was adjusted to 40t/d, the combustion period before the reversal was 1720s and the reversal time was 80 s.
The opening of each valve was adjusted by 10%. And controlling the gas flow, the combustion-supporting air flow, the cooling air flow, the rotating speed of a fan of the combustion-supporting air and the rotating speed of a fan of the cooling air, so that the temperature in the direct connection channel is increased to 900 ℃ at the temperature increase rate of 12 ℃/h.
S8, a fourth heat preservation stage:
keeping the temperature for 48h under the condition that the temperature of the direct connection channel is 900 ℃.
S9, stopping the kiln, detaching the ignition burner, installing the optical pyrometer, and turning to the spray gun to introduce gas for ignition.
In the first temperature raising stage, the second temperature raising stage, the third temperature raising stage, and the fourth temperature raising stage of examples 1 to 3, the gas flow rate, the combustion air flow rate, the cooling air flow rate, the rotation speed of the fan of the combustion air, and the rotation speed of the fan of the cooling air are shown in table 1. It is understood that the amount of coal gas, the amount of air, and the fan rotational speed need to be adjusted adaptively according to the temperature rise rate in each temperature rise stage, and therefore, the amount of coal gas, the amount of air, and the fan rotational speed are controlled within a certain range of values in each embodiment.
TABLE 1. amount of coal gas, air quantity and fan speed
Observing the double-hearth lime shaft kiln subjected to kiln drying treatment by adopting the kiln drying method provided by the embodiment 1-3, wherein the dewatering and the drainage of the refractory material of the kiln body are uniform and sufficient, and the high-temperature strength is effectively formed; meanwhile, the phenomena of cracking of bricks, damage to the special-shaped bricks of the direct-connection channel arch doors, cracking of furnace walls and the like are effectively improved, the defects and problems of cracks, peeling and falling are greatly reduced, and the production operation life of the double-chamber lime shaft kiln is prolonged.
The embodiments described above are some, but not all embodiments of the present application. The detailed description of the embodiments of the present application is not intended to limit the scope of the claimed application, but is merely representative of selected embodiments of the application. All other embodiments, which can be derived by a person skilled in the art from the embodiments given herein without making any creative effort, shall fall within the protection scope of the present application.
Claims (10)
1. A kiln drying method of a double-chamber lime shaft kiln is characterized by comprising a first heating stage, a first heat preservation stage, a second heating stage, a second heat preservation stage, a third heating stage, a third heat preservation stage, a fourth heating stage and a fourth heat preservation stage which are sequentially carried out on a direct connection channel of the double-chamber lime shaft kiln;
wherein the heating rate of each heating stage is less than or equal to 15 ℃/h; the heat preservation temperature of the first heat preservation stage is 142.5-157.5 ℃, the heat preservation temperature of the second heat preservation stage is 285-315 ℃, the heat preservation temperature of the third heat preservation stage is 570-630 ℃, and the heat preservation temperature of the fourth heat preservation stage is 855-945 ℃.
2. The kiln drying method according to claim 1, wherein the temperature rise rate of the first temperature rise stage is 12-13 ℃/h, and the temperature rise time of the first temperature rise stage is 11-13 h;
optionally, in the first temperature raising stage, the gas flow is 250-350 m3The flow of combustion-supporting air is 1000-2000 m3The flow rate of cooling air is 1500-2500 m3/h。
3. The kiln drying method according to claim 2, wherein the holding time of the first holding stage is 23 to 25 hours.
4. The kiln drying method according to claim 1, wherein the temperature rise rate of the second temperature rise stage is 12-13 ℃/h, and the temperature rise time of the second temperature rise stage is 11-13 h;
optionally, in the second temperature rise stage, the gas flow is 500-600 m3The flow of combustion-supporting air is 1000-2000 m3The flow rate of cooling air is 1500-2500 m3/h。
5. The kiln drying method according to claim 4, wherein the holding time of the second holding stage is 23 to 25 hours.
6. The kiln drying method according to claim 1, wherein the temperature rise rate of the third temperature rise stage is 12-14 ℃/h, and the temperature rise time of the third temperature rise stage is 21-25 h;
optionally, in the third temperature raising stage, the gas flow is 600-900 m3The flow of combustion-supporting air is 2000-3000 m3The flow rate of cooling air is 2500-3500 m3/h。
7. The kiln drying method according to claim 6, wherein the heat-retaining time of the third heat-retaining stage is 47-49 hours.
8. The kiln drying method according to claim 1, wherein the temperature rise rate of the fourth temperature rise stage is 12-14 ℃/h, and the temperature rise time of the fourth temperature rise stage is 21-25 h;
optionally, in the fourth temperature rise stage, the gas flow is 1000-1500 m3The flow of combustion-supporting air is 3500-5000 m3The flow rate of cooling air is 6500-7500 m3/h。
9. The kiln drying method according to claim 8, wherein the heat-preserving time of the fourth heat-preserving stage is 47-49 hours.
10. Kiln process according to any of claims 1 to 9, characterized in that, before the fourth ramp phase, the double-chambered lime shaft kiln has a throughput of 40t/d, discharging 1 batch per hour; optionally, the combustion period before reversing is 3520s, and the reversing time is 80 s;
and/or, starting from the fourth temperature rise stage, the output of the double-chamber lime shaft kiln is 20t/d, and 1 batch of materials are discharged per hour; optionally, the combustion period before the commutation is 1720s, and the commutation time is 80 s.
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Citations (4)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN101738091A (en) * | 2008-11-07 | 2010-06-16 | 首钢总公司 | Method for baking shaft kiln |
| CN103508687A (en) * | 2012-06-25 | 2014-01-15 | 上海宝冶建设工业炉工程技术有限公司 | Sleeve lime kiln empty-kiln baking method |
| CN109282640A (en) * | 2018-09-29 | 2019-01-29 | 攀钢集团钒钛资源股份有限公司 | Turn round kilning kiln method |
| CN111302675A (en) * | 2020-04-27 | 2020-06-19 | 垣曲县五龙镁业有限责任公司 | Method and system for calcining dolomite in heat accumulating type energy-saving double-hearth shaft kiln |
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2020
- 2020-08-24 CN CN202010861537.2A patent/CN111943531A/en active Pending
Patent Citations (4)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN101738091A (en) * | 2008-11-07 | 2010-06-16 | 首钢总公司 | Method for baking shaft kiln |
| CN103508687A (en) * | 2012-06-25 | 2014-01-15 | 上海宝冶建设工业炉工程技术有限公司 | Sleeve lime kiln empty-kiln baking method |
| CN109282640A (en) * | 2018-09-29 | 2019-01-29 | 攀钢集团钒钛资源股份有限公司 | Turn round kilning kiln method |
| CN111302675A (en) * | 2020-04-27 | 2020-06-19 | 垣曲县五龙镁业有限责任公司 | Method and system for calcining dolomite in heat accumulating type energy-saving double-hearth shaft kiln |
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