CN112250326B - Streamline lime kiln - Google Patents
Streamline lime kiln Download PDFInfo
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- CN112250326B CN112250326B CN202011295733.4A CN202011295733A CN112250326B CN 112250326 B CN112250326 B CN 112250326B CN 202011295733 A CN202011295733 A CN 202011295733A CN 112250326 B CN112250326 B CN 112250326B
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- 235000008733 Citrus aurantifolia Nutrition 0.000 title claims abstract description 114
- 235000011941 Tilia x europaea Nutrition 0.000 title claims abstract description 114
- 239000004571 lime Substances 0.000 title claims abstract description 114
- 238000001354 calcination Methods 0.000 claims abstract description 104
- 238000001816 cooling Methods 0.000 claims abstract description 22
- 239000007921 spray Substances 0.000 claims description 57
- 239000002994 raw material Substances 0.000 claims description 43
- 235000019738 Limestone Nutrition 0.000 claims description 20
- 239000006028 limestone Substances 0.000 claims description 20
- 230000000694 effects Effects 0.000 abstract description 17
- 238000004519 manufacturing process Methods 0.000 abstract description 13
- 238000010304 firing Methods 0.000 abstract description 4
- 240000006909 Tilia x europaea Species 0.000 description 90
- 101100399296 Mus musculus Lime1 gene Proteins 0.000 description 89
- 239000000463 material Substances 0.000 description 17
- UGFAIRIUMAVXCW-UHFFFAOYSA-N Carbon monoxide Chemical compound [O+]#[C-] UGFAIRIUMAVXCW-UHFFFAOYSA-N 0.000 description 9
- 229910000831 Steel Inorganic materials 0.000 description 9
- 239000003546 flue gas Substances 0.000 description 9
- 239000010959 steel Substances 0.000 description 9
- 239000011449 brick Substances 0.000 description 8
- 239000011148 porous material Substances 0.000 description 7
- ODINCKMPIJJUCX-UHFFFAOYSA-N Calcium oxide Chemical compound [Ca]=O ODINCKMPIJJUCX-UHFFFAOYSA-N 0.000 description 6
- 238000010586 diagram Methods 0.000 description 6
- 239000011819 refractory material Substances 0.000 description 6
- 238000000354 decomposition reaction Methods 0.000 description 5
- 238000009826 distribution Methods 0.000 description 5
- 238000004873 anchoring Methods 0.000 description 4
- 238000000034 method Methods 0.000 description 4
- 230000008569 process Effects 0.000 description 4
- 239000000292 calcium oxide Substances 0.000 description 3
- 235000012255 calcium oxide Nutrition 0.000 description 3
- 238000002485 combustion reaction Methods 0.000 description 3
- 238000010276 construction Methods 0.000 description 3
- 230000009467 reduction Effects 0.000 description 3
- VTYYLEPIZMXCLO-UHFFFAOYSA-L Calcium carbonate Chemical compound [Ca+2].[O-]C([O-])=O VTYYLEPIZMXCLO-UHFFFAOYSA-L 0.000 description 2
- 239000013590 bulk material Substances 0.000 description 2
- 238000006243 chemical reaction Methods 0.000 description 2
- 230000007423 decrease Effects 0.000 description 2
- 230000003247 decreasing effect Effects 0.000 description 2
- 238000004134 energy conservation Methods 0.000 description 2
- 239000007789 gas Substances 0.000 description 2
- 239000002184 metal Substances 0.000 description 2
- 238000005728 strengthening Methods 0.000 description 2
- 208000012868 Overgrowth Diseases 0.000 description 1
- 235000017899 Spathodea campanulata Nutrition 0.000 description 1
- 244000188014 Spathodea campanulata Species 0.000 description 1
- QVGXLLKOCUKJST-UHFFFAOYSA-N atomic oxygen Chemical compound [O] QVGXLLKOCUKJST-UHFFFAOYSA-N 0.000 description 1
- 238000005452 bending Methods 0.000 description 1
- 229910000019 calcium carbonate Inorganic materials 0.000 description 1
- 230000005465 channeling Effects 0.000 description 1
- 150000001875 compounds Chemical class 0.000 description 1
- 230000008602 contraction Effects 0.000 description 1
- 239000012530 fluid Substances 0.000 description 1
- 239000000446 fuel Substances 0.000 description 1
- 238000009776 industrial production Methods 0.000 description 1
- JEIPFZHSYJVQDO-UHFFFAOYSA-N iron(III) oxide Inorganic materials O=[Fe]O[Fe]=O JEIPFZHSYJVQDO-UHFFFAOYSA-N 0.000 description 1
- 239000001095 magnesium carbonate Substances 0.000 description 1
- ZLNQQNXFFQJAID-UHFFFAOYSA-L magnesium carbonate Chemical compound [Mg+2].[O-]C([O-])=O ZLNQQNXFFQJAID-UHFFFAOYSA-L 0.000 description 1
- 229910000021 magnesium carbonate Inorganic materials 0.000 description 1
- 238000012423 maintenance Methods 0.000 description 1
- 238000012986 modification Methods 0.000 description 1
- 230000004048 modification Effects 0.000 description 1
- 239000001301 oxygen Substances 0.000 description 1
- 229910052760 oxygen Inorganic materials 0.000 description 1
- 239000002245 particle Substances 0.000 description 1
- 238000012545 processing Methods 0.000 description 1
- 230000002035 prolonged effect Effects 0.000 description 1
- 238000011160 research Methods 0.000 description 1
- 239000004576 sand Substances 0.000 description 1
- 238000005507 spraying Methods 0.000 description 1
- 238000009628 steelmaking Methods 0.000 description 1
- 230000007704 transition Effects 0.000 description 1
- 238000009423 ventilation Methods 0.000 description 1
- 238000003466 welding 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
-
- 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
- Y02P40/40—Production or processing of lime, e.g. limestone regeneration of lime in pulp and sugar mills
Landscapes
- 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)
- Vertical, Hearth, Or Arc Furnaces (AREA)
- Furnace Details (AREA)
Abstract
The invention relates to a streamline lime kiln, which comprises a kiln body which is vertically arranged and provided with a kiln chamber, wherein the kiln chamber is divided into a preheating zone, a calcining zone and a cooling zone from top to bottom, the inner wall of the kiln body corresponding to the calcining zone is a streamline smooth curved surface with a downward tapered diameter, and the curvature of the streamline smooth curved surface is more than 0 and less than or equal to 1/3. The streamline lime kiln overcomes the kiln wall effect caused by the kiln chamber of the conventional cylindrical straight-barrel type calcining zone, and effectively solves the problems of uneven lime firing degree, fluctuation of product quality, safety production accidents, equipment service life damage and the like caused by the kiln wall effect.
Description
Technical Field
The invention relates to the field of industrial furnace lime kilns, in particular to a streamline lime kiln.
Background
Compared with common lime, the active lime has the advantages of high porosity, sponginess, fine grain structure and the like, and can complete the steelmaking slag-forming reaction more quickly. The Maiz double-chamber kiln, the sleeve kiln and the beam lime kiln are main shaft kiln equipment for producing active lime at present, and raw material limestone is put into the kiln and calcined to obtain the product active lime.
The calcination temperature of the limestone must be strictly controlled within the range of 1100-1150 ℃. Too low a temperature, insufficient limestone decomposition, known as green burning; the excessive temperature, the overgrowth of the lime grain structure, is called overburning. Both raw and overburn can lead to reduced lime activity and unacceptable product. Oxygen and fuel are combusted at the burner of the shaft kiln to generate high-temperature flue gas, the flue gas flows to the lower part of the kiln chamber, and the temperature of the flue gas gradually decreases along with the decrease of the height of the kiln chamber. In shaft kilns, calcination of the active lime can only be carried out in cocurrent flow, not in countercurrent flow. This is because a large amount of heat energy needs to be absorbed in the early stage of the limestone decomposition reaction, and the amount of energy absorbed in the middle and later stages of the reaction is small. Too high a flue gas temperature can easily cause excessive burning of lime. The flue gas temperature variation for co-current calcination is consistent with the energy variation required for limestone calcination, while the flue gas temperature variation for counter-current combustion is the opposite.
According to the state of the materials in the kiln, the lime kiln can be divided into three sections, namely a preheating zone, a calcining zone and a cooling zone. Raw limestone is heated in a preheating zone, decomposed in a calcining zone and active lime is generated, and the product is cooled in a cooling zone at the lower part of the kiln chamber and then conveyed to a warehouse or a downstream production line.
The structure of the traditional Malz double-hearth kiln is shown in fig. 1, the kiln comprises two kiln bodies 01 which are vertically arranged and provided with kiln bores 011, the lower parts of the two kiln bodies 01 are communicated through pipelines, one of the kiln bodies 01 can discharge tail gas into the other kiln body 01 during calcination, and the other kiln body 01 can store heat. The upper part of each kiln body 01 is provided with a plurality of spray guns 02 at intervals along the circumference Xiang Jun, and the outlet end of each spray gun 02 is arranged downwards. The preheating zone of the kiln body 01 is arranged above the position of the outlet end of the spray gun 02, and the calcining zone and the cooling zone are arranged below the outlet end of the spray gun 02 in sequence.
The conventional sleeve kiln has a structure as shown in fig. 2, including a kiln body 01 (which may also be called an outer sleeve) vertically disposed and having a kiln bore 011, and an inner sleeve 012 provided in the kiln body 01, and limestone is calcined in an annular space formed between the kiln body 01 and the inner sleeve 012. A plurality of spray guns 02 are arranged at intervals along the circumferential direction at the upper part of the kiln body 01, a plurality of cooling air pipelines 03 are arranged at intervals along the circumferential direction at the lower part of the kiln body 01, and the outlet end of each spray gun 02 and the outlet end of each cooling air pipeline 03 are arranged along the horizontal direction. The preheating zone of the kiln body 01 is arranged above the spray gun 02, a calcining zone is arranged between the lower part of the spray gun 02 and the cooling air pipeline 03, and a cooling zone is arranged below the cooling air pipeline 03.
The structure of a traditional beam lime kiln is shown in fig. 3, and comprises a kiln body 01 which is vertically arranged and provided with a kiln chamber 011, an upper spray gun 04 (also known as an upper combustion beam) and a lower spray gun 05 (also known as a lower combustion beam) which are arranged at intervals up and down are arranged on the kiln body 01, an upper air suction beam 06 and a lower air suction beam 07 are respectively arranged on the kiln body 01 and above the upper spray gun 04 and below the lower spray gun 05, and outlet ends of the upper spray gun 04, the lower spray gun 05, the upper air suction beam 06 and the lower air suction beam 07 are all arranged along the horizontal direction. A preheating zone is arranged between the upper suction beam 06 and the upper spray gun 04, a front calcining zone is arranged between the upper spray gun 04 and the lower spray gun 05, a rear calcining zone is arranged below the lower spray gun 05, and the front calcining zone and the rear calcining zone form the whole calcining zone of the kiln body 01; a cooling belt is arranged between the rear calcination belt and the lower suction beam 07.
However, the traditional vertical kiln equipment such as a Maitzfeld double-chamber kiln, a sleeve kiln, a beam lime kiln and the like are cylindrical straight cylinders, the inner wall of the kiln body at the position of the calcining zone is straight cylinders, and kiln wall effects exist in the production of the cylindrical straight cylinder lime kiln, namely, the central air flow is insufficient, and the edge air flow is strong. The reason for kiln wall effect: firstly, the gap between the kiln wall and the material is larger than the gap between the material and the material; secondly, the limestone volume is contracted during calcination, so that gaps between kiln walls and materials are further increased. When the resistance of the material layer to the flue gas is uneven, the flue gas tends to circulate from the edge kiln wall with low density and low resistance. And kiln wall effects can create a number of hazards: the temperature and the air flow distribution in the kiln are uneven, so that lime is easy to burn on the kiln wall and the center is easy to burn, and the quality of the finished product is uneven and has large fluctuation. A wind tunnel appears near the wall of the kiln with smooth ventilation, and materials in the situation suddenly collapse; when serious, even fire balls or high-temperature air columns rush out of the surface of the materials, the service life of equipment is influenced, and safety production accidents are caused. When the air pressure in the kiln is low, the kiln wall can be at high temperature of 1400 ℃ to influence the service life of the refractory material.
Accordingly, the present inventors have developed a streamlined lime kiln to overcome the shortcomings of the prior art by years of experience and practice in the relevant industry.
Disclosure of Invention
The invention aims to provide a streamline lime kiln, which overcomes the kiln wall effect caused by the kiln chamber of a traditional cylindrical and straight-barrel type calcining zone and effectively solves the problems of uneven lime firing degree, fluctuation of product quality, safety production accidents, equipment service life damage and the like caused by the kiln wall effect.
The invention aims to realize that a streamline lime kiln comprises a kiln body which is vertically arranged and provided with a kiln chamber, wherein the kiln chamber is divided into a preheating zone, a calcining zone and a cooling zone from top to bottom, the inner wall of the kiln body corresponding to the calcining zone is a streamline smooth curved surface with the diameter gradually reduced downwards, and the curvature of the streamline smooth curved surface is more than 0 and less than or equal to 1/3.
In a preferred embodiment of the present invention, the top end inner diameter of the streamline smooth curved surface is a multiple of 1 time to 5 times larger than the bottom end inner diameter of the streamline smooth curved surface.
In a preferred embodiment of the present invention, the curvature of each point on the streamlined smooth curved surface satisfies the following formula:
wherein C represents the curvature of a certain point on the streamline smooth curved surface, beta% represents the proportion of CaCO 3 in the raw materials fired in the streamline lime kiln, 1-beta% represents the proportion of MgCO 3 in the raw materials fired in the streamline lime kiln, and H represents the vertical height of the calcining zone; when the kiln type of the streamline lime kiln is a Maiz double-chamber kiln or a beam type lime kiln, R represents the inner radius of the kiln body at the boundary of the preheating zone and the calcining zone; when the kiln type of the streamline lime kiln is a sleeve kiln, R represents the difference between the inner radius of the outer sleeve and the inner radius of the inner sleeve at the boundary between the preheating zone and the calcining zone; Δy represents the vertical distance between a point on the streamlined smooth curved surface and the top end of the calcining zone, Representing the true density of the fired raw material in a streamlined lime kiln,/>The apparent density of the fired raw material in the streamlined lime kiln is shown, K being a coefficient.
In a preferred embodiment of the invention, when the raw material of the streamline lime kiln is a sheet raw material, K is 0.1; when the raw material of the streamline lime kiln is spherical, K is 0.02.
In a preferred embodiment of the invention, the kiln type of the streamline lime kiln is a Maiz double-hearth kiln or a sleeve kiln, and the height of the bottom end of the calcining zone is 1/3-1/4 of the height of the kiln body.
In a preferred embodiment of the invention, the kiln type of the streamline lime kiln is a beam lime kiln, an upper spray gun and a lower spray gun which are arranged at intervals up and down are arranged on the kiln body, and a kiln chamber part between the positions 0.5-4 m below the upper spray gun and the lower spray gun forms a calcining zone.
In a preferred embodiment of the invention, the kiln type of the streamline lime kiln is a melz double-hearth kiln, and the melz double-hearth kiln comprises two kiln bodies which are parallel to each other, and the lower parts of the two kiln bodies are communicated through a pipeline; the upper part of each kiln body is provided with a plurality of spray guns along the circumference Xiang Jun at intervals, and an included angle exists between the outlet direction of the spray gun and the vertical direction.
In a preferred embodiment of the present invention, the angle between the outlet direction of the spray gun and the vertical direction is greater than 0 ° and less than or equal to 9 °.
In a preferred embodiment of the invention, the wall thickness of the kiln body between the top end and the bottom end of the calcining zone is greater than the wall thickness of the kiln body corresponding to the preheating zone.
In a preferred embodiment of the invention, the inner wall and the outer wall of the preheating zone are cylindrical surfaces, the outer wall of the upper part of the calcining zone is cylindrical surface, the outer wall of the lower part of the calcining zone is conical surface with the diameter gradually decreasing downwards, and the wall thickness of the kiln body corresponding to the bottom end of the conical surface is larger than the wall thickness of the kiln body corresponding to the boundary between the preheating zone and the calcining zone.
By adopting the streamline smooth curved surface on the kiln wall of the calcining zone part, the streamline lime kiln can strengthen the central air flow, reduce the edge air flow, has high heat energy utilization rate, saves energy and reduces emission, and finally ensures that the heat flow intensity of the same horizontal section in the kiln is uniformly distributed, and the firing degree of active lime is uniform. The problems of material collapse, upward channeling of air columns, high-temperature edge air flow and the like caused by kiln wall wind tunnels in kiln bores are solved effectively, production can be performed stably, fluctuation of product quality is small, and service life of equipment is longer.
Drawings
The following drawings are only for purposes of illustration and explanation of the present invention and are not intended to limit the scope of the invention. Wherein:
Fig. 1: is a schematic structural diagram of a Michelz double-hearth kiln in the prior art.
Fig. 2: is a structural schematic diagram of a sleeve kiln in the prior art.
Fig. 3: is a structural schematic diagram of a beam lime kiln in the prior art.
Fig. 4: the kiln type of the streamline lime kiln provided by the invention is a structural schematic diagram when the kiln type is a Michelz double-hearth kiln.
Fig. 5: the kiln type of the streamline lime kiln provided by the invention is a structural schematic diagram when the kiln type is a sleeve kiln.
Fig. 6: the kiln type of the streamline lime kiln provided by the invention is a structural schematic diagram when the kiln type is a beam type lime kiln. Wherein the arrows in the kiln bores in fig. 1-6 each represent the direction of heat flow of the calcining zone.
Fig. 7: the invention provides a partial enlarged view of a kiln body of a streamline lime kiln.
Fig. 8: an enlarged view of a portion of the spray gun of fig. 4 is provided for the present invention.
Fig. 9: the structure of the refractory brick is schematically shown.
Reference numerals illustrate:
the prior art comprises the following steps:
01. A kiln body; 011. a kiln chamber; 012. an inner sleeve;
02. A spray gun;
03. A cooling air duct;
04. a spray gun is arranged; 05. a lower spray gun; 06. an upper suction beam; 07. and a lower suction beam.
The invention comprises the following steps:
1. A kiln body; 11. a kiln chamber; 12. an inner sleeve; 13. a streamline smooth curved surface; 14. a cylindrical surface; 15. a conical surface; 16. a kiln body steel shell; 17. a refractory material; 18. refractory bricks; 181. a cambered surface;
2. a spray gun;
3. A cooling air duct;
4. a spray gun is arranged; 5. a lower spray gun; 6. an upper suction beam; 7. and a lower suction beam.
Detailed Description
For a clearer understanding of technical features, objects, and effects of the present invention, a specific embodiment of the present invention will be described with reference to the accompanying drawings.
As shown in fig. 4 to 9, the embodiment provides a streamline lime kiln, which comprises a kiln body 1 which is vertically arranged and provided with a kiln chamber 11, wherein the kiln chamber 11 is divided into a preheating zone, a calcining zone and a cooling zone from top to bottom, the inner wall of the kiln body 1 corresponding to the calcining zone is a streamline smooth curved surface 13 with a diameter gradually decreasing downwards, and the curvature of the streamline smooth curved surface 13 is more than 0 and less than or equal to 1/3.
Wherein, the streamline smooth curved surface 13 refers to a smooth curved surface with the inner diameter continuously shrinking along with the descending of the kiln body 1, and the model, the volume and the equipment parameters of the spray gun of the lime kiln all influence the geometric curvature and the shape of the streamline smooth curved surface 13; for the lime kiln of the "short fat type" the edge air flow is strong, so the geometrical curvature of the shrinkage is relatively large, while the geometrical curvature of the shrinkage of the lime kiln of the "high thin" type is relatively small, and the curvature is selected within 0 to 1/3 according to the actual situation, so as to ensure the product quality.
The streamline lime kiln in the embodiment is mainly suitable for three kiln types of a Maitzfeld double-hearth kiln, a sleeve kiln and a beam lime kiln, and the cross section of the kiln body 1 at the calcining zone is circular. The corresponding structure of each kiln type is as follows: (1) For the kiln type of the Maiz double-chamber kiln, as shown in fig. 4, the lime kiln comprises two kiln bodies 1 which are parallel to each other, and the lower parts of the two kiln bodies 1 are communicated through a pipeline. The upper part of each kiln body 1 is provided with a plurality of spray guns 2 along the circumference Xiang Jun at intervals, a preheating zone of the kiln body 1 is arranged above the position of the outlet end of each spray gun 2, and a calcining zone and a cooling zone are arranged below the outlet end of each spray gun 2 in sequence. (2) In the case of a kiln type of a sleeve kiln, as shown in fig. 5, a kiln body 1 of the lime kiln may be called an outer sleeve, an inner sleeve 12 is provided in the kiln body 1, a plurality of spray guns 2 are provided at intervals in the circumferential direction at the upper portion of the kiln body 1, and a plurality of cooling air pipes 3 are provided at intervals in the circumferential direction at the lower portion of the kiln body 1. The preheating zone of the kiln body 1 is arranged above the spray gun 2, a calcining zone is arranged between the lower part of the spray gun 2 and the cooling air pipeline 3, and a cooling zone is arranged below the cooling air pipeline 3. (3) In the kiln type beam type lime kiln, as shown in fig. 6, an upper lance 4 and a lower lance 5 are provided on a kiln body 1 at an upper and lower interval, and an upper suction beam 6 and a lower suction beam 7 are provided on the kiln body 1 above the upper lance 4 and below the lower lance 5, respectively. A preheating zone is arranged between the upper air suction beam 6 and the upper spray gun 4, a front calcining zone is arranged between the upper spray gun 4 and the lower spray gun 5, a rear calcining zone is arranged below the lower spray gun 5, the front calcining zone and the rear calcining zone form the whole calcining zone, and a cooling zone is arranged between the rear calcining zone and the lower air suction beam 7.
For the above three kiln-type lime kilns, the inner wall of the kiln body 1 corresponding to the calcining zone is designed to be smooth transition streamline in the embodiment, so that when the flue gas moves to the lower part of the kiln chamber 11, the size of the kiln chamber 11 gradually reduces, and high-temperature airflow fluid obliquely contacts the side wall of the kiln chamber 11 at a certain angle, which forces the too strong edge airflow to turn and be integrated into the central airflow. Meanwhile, the volume of the limestone is contracted in the decomposition reaction; the downward contracted streamline kiln chamber 11 just accords with the volume contraction trend of the materials, so that gaps between kiln walls and the materials can be reduced, and the edge airflow is further reduced.
Therefore, in the streamline lime kiln in the embodiment, the kiln wall of the calcining zone part adopts the streamline smooth curved surface 13, so that the central air flow can be enhanced, the edge air flow can be reduced, the heat energy utilization rate of the lime kiln is high, the energy is saved, the emission is reduced, and finally, the heat flow intensity distribution of the same horizontal section in the kiln is uniform, and the firing degree of active lime is uniform. The problems of material collapse, air column upward movement, high-temperature edge air flow and the like caused by kiln wall wind tunnel are solved in the kiln chamber 11, the production can be stably carried out, the fluctuation of product quality is small, and the service life of equipment is longer.
In a preferred embodiment, the top end inner diameter of the streamline-shaped smooth curved surface 13 is a multiple of 1 time to 5 times larger than the bottom end inner diameter of the streamline-shaped smooth curved surface 13. As the working environment in the kiln also affects the streamline kiln wall, the larger the air pressure in the kiln chamber 11 is, the stronger the edge air flow is, the larger the contracted curvature of the streamline kiln chamber 11 is, the higher the top end inner diameter of the streamline smooth curved surface 13 is than the multiple of the bottom end inner diameter of the streamline smooth curved surface 13, and the specific multiple is selected according to practical conditions.
More preferably, referring to fig. 7, the curvature of each point on the streamlined smooth curved surface 13 satisfies the following formula:
Wherein C represents the curvature of a certain point on the streamline smooth curved surface 13, beta% represents the proportion of CaCO 3 in the raw material fired in the streamline lime kiln (specifically, the mass ratio), 1-beta% represents the proportion of MgCO 3 in the raw material fired in the streamline lime kiln (specifically, the mass ratio), and H represents the vertical height of the calcining zone. When the kiln type of the streamline lime kiln is a Michelz double-chamber kiln or a beam type lime kiln, R represents the inner radius of the kiln body at the boundary between the preheating zone and the calcining zone (namely the inner diameter of the top end of the streamline smooth curved surface 13); when the kiln type of the streamline lime kiln is a sleeve kiln, R represents the difference between the inner radius of the outer sleeve and the inner radius of the inner sleeve 12 at the boundary between the preheating zone and the calcining zone. Δy represents the vertical distance between a point on the streamlined smooth curved surface 13 and the top end of the calcining zone (for example Δy shown in figure 7 represents the vertical distance between point a on the streamlined smooth curved surface 13 and the top end of the calcining zone), Representing the true density of the fired raw material in a streamlined lime kiln,/>The apparent density of the fired raw material in the streamlined lime kiln is shown, K being a coefficient.
Specifically, the curvature of a certain point on the streamline smooth curved surface 13 is the rotation rate of the tangential direction angle of the certain point on the curve to the arc length, which indicates the degree of deviation of the curve from the straight line, and the larger the curvature, the larger the degree of bending of the curve. It will be appreciated that since the cross section of the kiln body 1 at the calcining zone in this embodiment is circular, the curvature of points on the streamlined smooth curved surface 13 which are on the same horizontal plane is the same. The raw materials fired in the streamline lime kiln are limestone, the main components of the limestone are CaCO 3 and MgCO 3, and the contents of other components are small, so that the influence is negligible. The true density of the raw material is the density after compacting the limestone, and the apparent density of the raw material is the density when the limestone is porous in a loose state, which is the state of bulk limestone used when the raw material is added to the kiln body 1 in normal industrial production.
The curvature of each point on the streamline smooth curved surface 13 depends on the heat flow in the kiln, and the streamline smooth curved surface 13 reflects the heat flow with too strong edges to the center part of the kiln chamber 11, so that the purposes of strengthening the center air flow and reducing the center air flow are achieved. It has been found that the curvature of each point on the streamlined smooth curved surface 13 is mainly affected by three factors:
(1) The components of the raw materials burned in the lime kiln are as follows: in the process that the raw materials fall down in the calcining zone, the volume of the raw materials can shrink along with the temperature reduction of the kiln chamber 11, the raw materials fired in the lime kiln are limestone, and the main components are CaCO 3 and MgCO 3, but the shrinkage ratio of the two compounds is different, so that the proportion of the raw materials can influence the heat flow distribution of the calcining zone in the kiln chamber 11, further influence the curvature of the streamline smooth curved surface 13, and the shrinkage ratio of CaCO 3 is slightly smaller than that of MgCO 3.
(2) The shape of the raw materials: the pores among the spherical raw materials are larger, the resistance of heat flow passing through the raw materials is smaller, the heat flow passing through the materials is strong, so that the kiln wall effect is smaller, and the shrinkage degree of the streamline calcining zone is smaller, namely the corresponding curvature is smaller. After stacking the sheet raw materials, the pores among the raw materials are smaller, the resistance of heat flow passing through the pores is large, and the kiln wall effect is strong, so that the shrinkage degree of the calcining zone is larger, namely the corresponding curvature is larger.
(3) Pores generated by calcining the raw materials:
The limestone reacts in the calcination process:
CaCO3→CaO+CO2
MgCO3→MgO+CO2
The calcination and decomposition of the bulk raw materials produce CO 2 gas, the compact bulk raw materials can become loose and porous quicklime, the pores produced in the process can allow a small part of heat flow to pass through, and the larger the pores of the quicklime are, the stronger the heat flow passing through materials is, so the kiln wall effect is smaller, and the shrinkage degree of the calcining zone is small and the corresponding curvature is small. The porosity is in turn affected by a number of production parameter factors such as temperature, pressure, limestone particle size, blast flow rate, etc.
In the above formulaMainly represents the influence of the shrinkage proportion of CaCO 3 in the raw material on the curvature, and/>, in the formulaMainly shows the influence of the shrinkage proportion of MgCO 3 in the raw material on the curvature, and the/>Mainly represents the effect of pores generated during the calcination of the bulk material on the curvature, and/>, in the above formulaMainly the effect of the shape of the bulk material on the curvature. The coefficient K represents the influence degree of the shape of the raw material on the curvature, and when the raw material of the streamline lime kiln is a sheet raw material, the K is 0.1; when the raw material of the streamline lime kiln is spherical, K is 0.02, and the research shows that when the curvature of each point on the streamline smooth curved surface 13 meets the above formula, the heat flow intensity on each horizontal plane can be ensured to be uniform, so that the calcination symmetry of the active lime is effectively ensured, and the quality of the product is effectively ensured.
Further, the position of the streamline-shaped smooth curved surface 13 in this embodiment is the same as the position of the calcining zone, that is, the top end position and the bottom end position of the streamline-shaped smooth curved surface 13 are the top end position (i.e., the start position) and the bottom end position (i.e., the stop position) of the calcining zone, respectively. Mainly, the decomposition of the limestone is only carried out in the calcining zone, so that the heat flow outside the calcining zone has little influence on the quality of the product, and the limestone does not need to be streamline.
When the specific position of the calcining zone is designed, specific conditions such as specific kiln type, volume and the like need to be comprehensively considered so as to ensure good calcining effect. As a preferred embodiment, when the kiln type of the streamline lime kiln is a Michelz double-hearth kiln or a sleeve kiln, the height of the bottom end of the calcining zone is preferably 1/3-1/4 of the height of the kiln body 1, namely, the stop position of the calcining zone is preferably 1/3-1/4 of the height of the kiln body 1. When the kiln type of the streamline lime kiln is a beam lime kiln, the kiln chamber 11 between the positions of 0.5-4 m below the upper spray gun 4 and the lower spray gun 5 forms the calcining zone, that is, the stop position of the calcining zone is preferably 0.5-4 m below the lower spray gun 5. The part of the calcining zone below the lower spray gun 5 is a post calcining zone of a beam lime kiln, and the position of the post calcining zone is selected according to the influence of production conditions.
Further, when the kiln shape of the streamline lime kiln is a melz double-chamber kiln, in order to assist in strengthening the central air flow, as shown in fig. 8, an included angle exists between the outlet direction of the spray gun 2 and the vertical direction, that is, the spray gun 2 is inclined to the center line of the kiln chamber 11 by a certain angle, so that the heat flow intensity distribution is more uniform. The included angle theta between the outlet direction of the spray gun 2 and the vertical direction is preferably more than 0 degrees and less than or equal to 9 degrees, and the specific value is determined according to the production condition.
Further, since the calcining zone is the region with the worst working environment in the kiln chamber 11 of the lime kiln, the temperature is the highest and the heat flow intensity is the largest. The refractory material 17 of the calciner is the zone of greatest wear in the kiln chamber 11 and in special cases even burns red, through the kiln shell, causing safety accidents. Therefore, in this embodiment, in order to reduce the probability of burning red and burning through of the side wall of the kiln chamber 11 and reduce the accident rate, the wall thickness of the kiln body 1 corresponding to the top end and the bottom end of the calcining zone is greater than the wall thickness of the kiln body 1 corresponding to the preheating zone.
More preferably, the inner wall and the outer wall of the preheating zone are cylindrical surfaces, the outer wall of the upper part of the calcining zone is a cylindrical surface 14, the outer wall of the lower part of the calcining zone is a conical surface 15 with the diameter tapered downwards, and the wall thickness of the kiln body 1 corresponding to the bottom end of the conical surface 15 is larger than the wall thickness of the kiln body 1 corresponding to the boundary between the preheating zone and the calcining zone. Therefore, the outer wall of the kiln body 1 corresponding to the calcining zone is in a fold line shape, and the inner wall is streamline, so that compared with a traditional straight-tube lime kiln, the material resistance of the calcining zone is increased, and a thick-wall calcining zone is formed. And the increase of the thickness of the kiln wall corresponding to the calcining zone means that the kiln chamber 11 has better durability, prolongs the overhaul period of the kiln chamber 11, and can improve the equipment working rate and reduce the maintenance cost. Meanwhile, the outer wall of the kiln body 1 adopting the part adopts a folded line shape, so that the material can be saved, and the cost can be reduced.
Further, the streamline smooth curved surface 13 is formed by stacking refractory bricks 18 with different cambered surface curvatures, as shown in fig. 9, one surface of each refractory brick 18 is a smooth cambered surface 181, the other surfaces are rectangular, the curvature of each cambered surface 181 of each refractory brick 18 is calculated according to the calculation formula of the curvature, and the cambered surfaces 181 of a plurality of refractory bricks 18 are enclosed to form the streamline smooth curved surface 13.
In actual construction, the kiln body steel shells 16 are welded up one by one to form the required fold line type outer wall. Then spraying the refractory material 17 in the kiln body steel shell 16, and welding metal anchoring parts on the inner wall of the kiln body 1 to prevent the amorphous refractory material from falling off and form a whole with the kiln body steel shell 16. After the anchoring piece is welded, surface dirt is cleaned, sand is blasted to prevent rust, anchoring modes such as a metal net and a steel ring or a Y-shaped nail and a steel ring are adopted, the anchoring nails alternate transversely and longitudinally, and the distance is set to be 100-250 mm according to actual conditions.
When brickwork, the refractory bricks 18 are layered from the kiln wall lateral center line, and thermal expansion joints are reserved during construction. If the curvature of the streamline kiln body 1 is overlarge and the kiln body steel shell 16 is stressed too strongly, a circle of steel structure support can be arranged at the corresponding height along the central line, and the steel structure support acts on the lower concrete platform through the support column and is loaded by the concrete platform. The specific construction process is the prior art and will not be described in detail herein.
In summary, the streamline lime kiln in the embodiment has the following advantages:
(1) The inner wall of the kiln body 1 corresponding to the calcining zone adopts a streamline smooth curved surface 13, so that the heat flow in the kiln chamber 11 is uniformly distributed, and the active lime is calcined symmetrically; the edge air flow is small, the lime kiln has high heat energy utilization rate, and energy conservation and emission reduction are realized; production accidents caused by kiln wall effect are reduced, and the service life of equipment is longer; accidents such as kiln wall wind tunnel and material level collapse are reduced, and the production stability and the productivity of the lime kiln are correspondingly improved;
(2) During processing, the size of the kiln body 1 corresponding to the cooling belt below the calcining belt can be kept unchanged, the size of the calcining belt is properly enlarged, and the volume of the calcining belt can be enlarged on the premise of not increasing the lower foundation of the linear lime kiln, which means that the capacity of the lime kiln is improved. Namely, compared with the traditional lime kiln, the streamline lime kiln can increase the yield on the premise of not increasing the occupied area of the foundation, and the capacity can be increased by 25%.
(3) The wall thickness of the calcining zone is thicker than that of the preheating zone, and the thick-wall kiln chamber 11 with thicker refractory brick layer can reduce the probability of burning red and burning through of the side wall and prolong the overhaul period of the kiln chamber 11.
The whole streamline lime kiln improves the kiln chamber of the traditional cylindrical straight-tube lime kiln into a streamline thick-wall kiln chamber 11 combining a broken line type outer kiln shell and smooth curve inner wall brickwork, optimizes the heat flow distribution in the kiln chamber 11, reduces the kiln wall effect, reduces the production accident rate and prolongs the service life of equipment. Quality fluctuation of lime at the edge of the kiln wall and the center of the kiln chamber 11 is also controlled, and the heat energy utilization rate of the lime kiln can be improved, and the energy conservation and emission reduction can be realized. The capacity of the lime kiln can be improved on the premise of not increasing the occupied area of equipment. Meanwhile, the thickness of the refractory material of the calcining zone is increased by the thick-wall kiln chamber 11, the probability of burning red and burning through of the kiln chamber 11 is reduced, and the overhaul period of the lime kiln is prolonged.
The foregoing is illustrative of the present invention and is not to be construed as limiting the scope of the invention. Any equivalent changes and modifications can be made by those skilled in the art without departing from the spirit and principles of this invention, and are intended to be within the scope of this invention.
Claims (7)
1. A streamline lime kiln comprises a kiln body which is vertically arranged and provided with a kiln chamber, wherein the kiln chamber is divided into a preheating zone, a calcining zone and a cooling zone from top to bottom,
The inner wall of the kiln body corresponding to the calcining zone is a streamline smooth curved surface with the diameter tapered downwards, and the curvature of the streamline smooth curved surface is more than 0 and less than or equal to 1/3; the inner diameter of the top end of the streamline smooth curved surface is more than 1 time and less than or equal to 5 times of the inner diameter of the bottom end of the streamline smooth curved surface;
the curvature of each point on the streamline smooth curved surface meets the following formula:
Wherein C represents the curvature of a certain point on the streamline smooth curved surface, beta% represents the mass ratio of CaCO 3 in the raw materials fired in the streamline lime kiln, 1-beta% represents the mass ratio of MgCO 3 in the raw materials fired in the streamline lime kiln, and H represents the vertical height of the calcining zone;
When the kiln type of the streamline lime kiln is a Maiz double-chamber kiln or a beam lime kiln, R represents the inner radius of the kiln body at the boundary of the preheating zone and the calcining zone; when the kiln type of the streamline lime kiln is a sleeve kiln, R represents the difference between the inner radius of the outer sleeve and the inner radius of the inner sleeve at the boundary of the preheating zone and the calcining zone;
Δy represents the vertical distance between a point on the streamlined smooth curved surface and the top end of the calcining zone, Representing the true density of the fired raw material in the streamlined lime kiln,/>Representing the apparent density of the raw materials fired in the streamline lime kiln, wherein the raw materials fired in the streamline lime kiln are limestone, and K is a coefficient; when the raw materials of the streamline lime kiln are sheet raw materials, K is 0.1; when the raw material of the streamline lime kiln is spherical, K is 0.02.
2. The streamlined lime kiln according to claim 1, wherein,
The kiln type of the streamline lime kiln is a Maiz double-hearth kiln or a sleeve kiln, and the height of the bottom end of the calcining zone is 1/3-1/4 of the height of the kiln body.
3. The streamlined lime kiln according to claim 1, wherein,
The kiln type of the streamline lime kiln is a beam type lime kiln, an upper spray gun and a lower spray gun which are arranged up and down at intervals are arranged on the kiln body, and a kiln chamber part between the upper spray gun and a position 0.5-4 m below the lower spray gun forms the calcining zone.
4. The streamlined lime kiln according to claim 1, wherein,
The kiln type of the streamline lime kiln is a Maiz double-hearth kiln, the Maiz double-hearth kiln comprises two kiln bodies which are parallel to each other, and the lower parts of the two kiln bodies are communicated through a pipeline; the upper part of each kiln body is provided with a plurality of spray guns at intervals along the circumference Xiang Jun of the kiln body, and an included angle exists between the outlet direction of each spray gun and the vertical direction.
5. The streamlined lime kiln according to claim 4, wherein,
The included angle between the outlet direction of the spray gun and the vertical direction is more than 0 degrees and less than or equal to 9 degrees.
6. The streamlined lime kiln according to claim 1, wherein,
The wall thickness of the kiln body corresponding to the top end and the bottom end of the calcining zone is larger than that of the kiln body corresponding to the preheating zone.
7. The streamlined lime kiln according to claim 6, wherein,
The inner wall and the outer wall of the preheating zone are cylindrical surfaces, the outer wall of the upper part of the calcining zone is a cylindrical surface, the outer wall of the lower part of the calcining zone is a conical surface with the diameter gradually reduced downwards, and the wall thickness of the kiln body corresponding to the bottom end of the conical surface is larger than the wall thickness of the kiln body corresponding to the boundary between the preheating zone and the calcining zone.
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| CN202945167U (en) * | 2012-11-07 | 2013-05-22 | 广东韶钢松山股份有限公司 | Working lining structure of gas-burned lime shaft kiln |
| CN213570206U (en) * | 2020-11-18 | 2021-06-29 | 中冶京诚工程技术有限公司 | Streamline lime kiln |
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| CN202945167U (en) * | 2012-11-07 | 2013-05-22 | 广东韶钢松山股份有限公司 | Working lining structure of gas-burned lime shaft kiln |
| CN213570206U (en) * | 2020-11-18 | 2021-06-29 | 中冶京诚工程技术有限公司 | Streamline lime kiln |
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