CN112250326A

CN112250326A - Streamline lime kiln

Info

Publication number: CN112250326A
Application number: CN202011295733.4A
Authority: CN
Inventors: 蒋雨锟; 王得刚; 全强; 孟凯彪; 冯燕波; 田辉; 李照麟
Original assignee: MCC Capital Engineering and Research Incorporation Ltd
Current assignee: MCC Capital Engineering and Research Incorporation Ltd
Priority date: 2020-11-18
Filing date: 2020-11-18
Publication date: 2021-01-22
Anticipated expiration: 2040-11-18
Also published as: CN112250326B

Abstract

The invention relates to a streamline limekiln, which comprises a vertical kiln body 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. The streamline lime kiln overcomes the kiln wall effect caused by the traditional cylindrical and straight-barrel type calcining zone kiln chamber, and effectively solves the problems of uneven lime calcination degree, fluctuation of product quality, safety production accidents, damage to equipment service life and the like caused by the kiln wall effect.

Description

Streamline lime kiln

Technical Field

The invention relates to the field of industrial 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 more quickly finish the steelmaking slagging reaction. The Mailz double-chamber kiln, the sleeve kiln and the beam type lime kiln are main vertical 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 calcining temperature of the limestone must be strictly controlled within the range of 1100 ℃ to 1150 ℃. When the temperature is too low, the limestone is not fully decomposed and is called as burning; the crystal grain structure of lime grows too large when the temperature is too high, and the process is called overburning. Both raw burning and over burning can cause the activity of lime to be reduced and the product to be unqualified. Oxygen and fuel are combusted at a 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 is gradually reduced along with the reduction 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 the limestone decomposition reaction requires a large amount of heat energy to be absorbed in the early stage of the reaction, and the energy absorbed in the middle and later stages of the reaction is small. Too high a flue gas temperature easily causes the lime to be over-burnt. The flue gas temperature variation for co-current calcination coincides with the energy variation required for limestone calcination, while the flue gas temperature variation for counter-current combustion is the opposite.

The lime kiln can be divided into three sections, namely a preheating zone, a calcining zone and a cooling zone, according to the state of materials in the kiln. The raw material limestone is heated in a preheating zone, decomposition reaction is carried out in a calcining zone to generate active lime, and the product is cooled in a cooling zone at the lower part of a kiln chamber and then is conveyed to a warehouse or a downstream production line.

The structure of a traditional Maerz double-chamber kiln is shown in figure 1, and comprises two vertically arranged kiln bodies 01 with kiln chambers 011, wherein the lower parts of the two kiln bodies 01 are communicated through a pipeline, one of the two 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 circumferential direction, and the outlet ends of the spray guns 02 are 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 sequentially arranged below the outlet end of the spray gun 02.

A conventional sleeve kiln has a structure as shown in fig. 2, and includes a kiln body 01 (also referred to as an outer sleeve) vertically arranged and having a kiln chamber 011, and an inner sleeve 012 arranged 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 on the upper part of the kiln body 01 at intervals along the circumferential direction of the kiln body, a plurality of cooling air pipelines 03 are arranged on the lower part of the kiln body 01 at intervals along the circumferential direction of the kiln body, and the outlet ends of the spray guns 02 and the outlet ends of the cooling air pipelines 03 are arranged along the horizontal direction. The preheating zone of the kiln body 01 is arranged above the spray gun 02, the calcining zone is arranged between the lower part of the spray gun 02 and the cooling air pipeline 03, and the 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 is provided with a kiln chamber 011, wherein an upper spray gun 04 (also called an upper combustion beam) and a lower spray gun 05 (also called 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 air 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 distance below the lower spray gun 05 is a rear calcining zone, and the front calcining zone and the rear calcining zone form the whole calcining zone of the kiln body 01; a cooling zone is arranged between the post calcining zone and the lower air suction beam 07.

However, the traditional vertical kiln equipment such as the Maerz double-chamber kiln, the sleeve kiln, the beam lime kiln and the like are all cylindrical straight cylinders, the inner wall of the kiln body with the position of the calcining zone is all cylindrical, and the cylindrical straight cylinder lime kiln has the kiln wall effect in the production, namely insufficient central airflow and strong edge airflow. The cause of the kiln wall effect is as follows: firstly, the gap between the kiln wall and the material is larger than the gap between the material and the material; secondly, because the limestone can shrink in the calcination, the gap between the kiln wall and the material is further increased. When the resistance of the material bed to the smoke is uneven, the smoke tends to circulate from the kiln wall with low density and low resistance. And the kiln wall effect can cause a plurality of hazards: the temperature and airflow in the kiln are distributed unevenly, which causes the lime to be easy to over-burn on the kiln wall and easy to raw burn in the center, thus leading to uneven quality and large fluctuation of finished products. A wind tunnel appears near the kiln wall with smooth ventilation, and the local materials collapse suddenly; in severe cases, fire balls or high-temperature gas columns even rush out of the surface of the material, so that 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 generate high temperature of 1400 ℃, and the service life of the refractory material is influenced.

Therefore, the inventor provides a streamline lime kiln by virtue of experience and practice of related industries for many years so as to overcome the defects of the prior art.

Disclosure of Invention

The invention aims to provide a streamline lime kiln, which overcomes the kiln wall effect caused by the traditional cylindrical and straight-barrel type calcining zone kiln chamber and effectively solves the problems of uneven lime sintering degree, fluctuation of product quality, safety production accidents, damage to equipment service life and the like caused by the kiln wall effect.

The invention aims to realize the streamline limekiln, which comprises a vertical kiln body 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 greater than 0 and less than or equal to 1/3.

In a preferred embodiment of the present invention, the inner diameter of the top end of the streamline smooth curved surface is greater 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.

In a preferred embodiment of the present invention, the curvatures of the points on the streamline smooth curved surface satisfy the following formula:

wherein C represents the curvature of a certain point on the streamline smooth curved surface, and beta percent represents CaCO in the raw material fired in the streamline limekiln₃In proportion, 1-beta percent represents MgCO in the raw material fired in the streamline lime kiln₃OccupiedThe ratio H represents the vertical height of the calcining zone; when the kiln type of the streamline lime kiln is a Maerz double-hearth kiln or a beam type lime kiln, R represents the inner radius of a 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; ay represents the vertical distance between a point on the streamline smooth curved surface and the top end of the calcining zone,

representing the true density of the raw material fired in a streamlined lime kiln,

the apparent density of the raw material fired in the streamline limekiln is shown, and K is a coefficient.

In a preferred embodiment of the invention, when the raw material of the streamlined lime kiln is a sheet-shaped raw material, K is 0.1; when the raw material of the streamline lime kiln is a spherical raw material, K is 0.02.

In a preferred embodiment of the present invention, the kiln type of the streamlined lime kiln is a double-chamber merz kiln or a sleeve kiln, and the bottom end of the calcining zone is located at a height of 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 a kiln body, and a kiln chamber part between the upper spray gun and the lower spray gun at a position 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 Maerz double-chamber kiln, the Maerz double-chamber kiln comprises two parallel kiln bodies, and the lower parts of the two kiln bodies are communicated through a pipeline; the upper portion of every kiln body is equipped with a plurality of spray guns along its circumference equal interval, has the contained angle between the export direction of spray gun and the vertical direction.

In a preferred embodiment of the invention, the angle between the outlet direction of the lance and the vertical 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 present invention, the inner wall and the outer wall of the preheating zone are both 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 a diameter gradually decreasing downwards, and the wall thickness of the kiln body corresponding to the bottom end of the conical surface is greater than that of the kiln body corresponding to the boundary of the preheating zone and the calcining zone.

According to the streamline lime kiln, the kiln wall at the calcining zone part adopts the streamline smooth curved surface, so that central airflow can be strengthened, edge airflow can be reduced, the heat utilization rate of the lime kiln is high, energy is saved, emission is reduced, the heat flow intensity of the same horizontal section in the lime kiln is uniformly distributed, and the active lime firing degree is uniform. The problems of material collapse, upward gas column channeling, high-temperature edge airflow and the like caused by the wind tunnel of the kiln wall do not occur in the kiln chamber due to the kiln wall effect are effectively overcome, the production can be stably carried out, the product quality fluctuation is small, and the service life of equipment is longer.

Drawings

The drawings are only for purposes of illustrating and explaining the present invention and are not to be construed as limiting the scope of the present invention. Wherein:

FIG. 1: is a schematic structural diagram of a Maerz double-chamber 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 middle beam type lime kiln in the prior art.

FIG. 4: the invention provides a structural schematic diagram of a streamlined lime kiln when the kiln type of the streamlined lime kiln is a Maerz double-chamber kiln.

FIG. 5: the invention provides a structural schematic diagram of a streamlined lime kiln when the kiln type is a sleeve kiln.

FIG. 6: the invention provides a structural schematic diagram of a streamlined lime kiln when the kiln type of the streamlined lime kiln is a beam type lime kiln. The arrows in the kiln bores in fig. 1 to 6 each represent the direction of the heat flow of the calcining zone.

FIG. 7: is a partial enlarged view of the kiln body of the streamline lime kiln provided by the invention.

FIG. 8: an enlarged view of a portion of the lance of figure 4 is provided for the present invention.

FIG. 9: is a structural schematic diagram of the refractory brick provided by the invention.

The reference numbers illustrate:

the prior art is as follows:

01. a kiln body; 011. a kiln chamber; 012. an inner sleeve;

02. a spray gun;

03. a cooling air duct;

04. an upper spray gun; 05. a lower spray gun; 06. an upper suction beam; 07. a lower suction beam.

The invention comprises the following steps:

1. a kiln body; 11. a kiln chamber; 12. an inner sleeve; 13. streamline smooth curved surface; 14. a cylindrical surface; 15. a conical surface; 16. a kiln body steel shell; 17. a refractory material; 18. a refractory brick; 181. a cambered surface;

2. a spray gun;

3. a cooling air duct;

4. an upper spray gun; 5. a lower spray gun; 6. an upper suction beam; 7. a lower suction beam.

Detailed Description

In order to more clearly understand the technical features, objects, and effects of the present invention, embodiments of the present invention will now be described with reference to the accompanying drawings.

As shown in fig. 4 to 9, the present embodiment provides a streamlined lime kiln, which includes a vertical kiln body 1 having a kiln chamber 11, 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 streamlined smooth curved surface 13 with a downward tapered diameter, and the curvature of the streamlined smooth curved surface 13 is greater than 0 and less than or equal to 1/3.

The streamline smooth curved surface 13 is a smooth curved surface with the inner diameter continuously shrinking along with the reduction of the height of the kiln body 1, and the geometric curvature and the shape of the streamline smooth curved surface 13 can be influenced by the model and the volume of the lime kiln and the equipment parameters of the spray gun; for the 'squat type' lime kiln, the edge airflow is strong, so the contraction geometric curvature is relatively large, and for the 'high and thin type' lime kiln, the contraction geometric curvature is relatively small, and the curvature is selected from 0 to 1/3 according to actual conditions so as to ensure the product quality.

The streamline lime kiln in the embodiment is mainly suitable for three types of kilns, namely a Maerz double-hearth kiln, a sleeve kiln and a beam type lime kiln, and the cross section of a kiln body 1 at a calcining zone is circular. The corresponding structure of each kiln type is as follows: (1) in the case of a double-chamber kiln of the type of a maerz, as shown in fig. 4, the lime kiln comprises two parallel kiln bodies 1, the lower parts of the two kiln bodies 1 being in communication with each other by a duct. A plurality of spray guns 2 are arranged at intervals on the upper part of each kiln body 1 along the circumferential direction, a preheating zone of each kiln body 1 is arranged above the position of an outlet end of each spray gun 2, and a calcining zone and a cooling zone are sequentially arranged below the outlet end of each spray gun 2. (2) In the case of a sleeve kiln, as shown in fig. 5, the kiln body 1 of the lime kiln may also be referred to as an outer sleeve, an inner sleeve 12 is provided in the kiln body 1, a plurality of lances 2 are provided at intervals in the circumferential direction at the upper part of the kiln body 1, and a plurality of cooling air ducts 3 are provided at intervals in the circumferential direction at the lower part of the kiln body 1. The upper part of the spray gun 2 is a preheating zone of the kiln body 1, 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 lime kiln of which the kiln type is a beam type, as shown in fig. 6, an upper spray gun 4 and a lower spray gun 5 which are arranged at intervals up and down are arranged on a kiln body 1, and an upper suction beam 6 and a lower suction beam 7 are respectively arranged on the kiln body 1 and above the upper spray gun 4 and below the lower spray gun 5. A preheating zone is arranged between the upper air suction beam 6 and the upper spray gun 4, a preposed calcining zone is arranged between the upper spray gun 4 and the lower spray gun 5, a distance below the position of the lower spray gun 5 is a postposition calcining zone, the preposed calcining zone and the postposition calcining zone form the whole calcining zone, and a cooling zone is arranged between the postposition calcining zone and the lower air suction beam 7.

For the lime kilns of the three kiln types, the inner walls of the kiln body 1 corresponding to the calcining zones of the lime kilns are designed to be in a smooth transition streamline shape 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 is gradually reduced, and high-temperature airflow fluid obliquely contacts the side wall of the kiln chamber 11 at a certain angle, so that the excessively strong edge airflow is forced to be diverted and merged into the central airflow. Meanwhile, the limestone shrinks in volume in the decomposition reaction; and the streamline kiln chamber 11 which contracts downwards just accords with the trend of material volume contraction, so that the gap between the kiln wall and the material can be reduced, and the edge airflow is further reduced.

Therefore, in the streamlined lime kiln in the embodiment, the kiln wall at the calcining zone part adopts the streamlined smooth curved surface 13, so that the central airflow can be strengthened, the edge airflow can be reduced, the heat energy utilization rate of the lime kiln is high, energy is saved, emission is reduced, the heat flow intensity of the same horizontal section in the lime kiln is uniformly distributed, and the active lime firing degree is uniform. The problems of material collapse, upward gas column channeling, high-temperature edge airflow and the like caused by a kiln wall wind tunnel do not occur in the kiln chamber 11 due to the kiln wall effect are effectively overcome, the production can be stably carried out, the product quality fluctuation is small, and the service life of equipment is longer.

In a preferred embodiment, the inner diameter of the top end of the streamline smooth curved surface 13 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 13. Because the working environment in the kiln can also influence the streamlined kiln wall, the larger the air pressure in the kiln chamber 11 is, the stronger the edge air flow is, the larger the contraction curvature of the streamlined kiln chamber 11 is, the higher the multiple of the top end inner diameter of the streamlined smooth curved surface 13 to the bottom end inner diameter of the streamlined smooth curved surface 13 is, and the specific multiple is selected according to the actual situation.

More preferably, referring to fig. 7, the curvatures of the points on the streamline smooth curved surface 13 satisfy the following formula:

wherein C represents the curvature of a certain point on the streamline smooth curved surface 13, and beta% represents CaCO in the raw material fired in the streamline limekiln₃In the proportion (specifically, mass ratio), 1-beta% represents MgCO in the raw material fired in the streamlined lime kiln₃In the ratio (specifically, mass ratio), H represents the vertical height of the calcining zone. When the kiln type of the streamline lime kiln is a Maerz double-hearth kiln or a beam lime kiln, R represents the inner radius of a kiln body at the boundary of 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 streamlined 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. Deltay represents the vertical distance between a point on the streamline smooth curve 13 and the tip of the calcining zone (for example deltay shown in figure 7 represents the vertical distance between a point on the streamline smooth curve 13 and the tip of the calcining zone),

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 point on the curve to the arc length, and 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 can be understood that, since the cross section of the kiln body 1 at the calcining zone is circular in this embodiment, the curvatures of points on the streamline smooth curved surface 13 on the same horizontal plane are the same. The raw material fired in the streamline limekiln is limestone, and the main component of the limestone is CaCO₃And MgCO₃The other components are present in small amounts, the effect of which is negligible. The actual density of the raw material refers to the density of the compacted limestone, the apparent density of the raw material refers to the density of the limestone with pores in a loose state, and the loose state refers to the state of the bulk limestone used when the raw material is added to the kiln body 1 in normal industrial production.

The curvatures of all points on the streamline smooth curved surface 13 depend on heat flow in the kiln, and the streamline smooth curved surface 13 reflects the heat flow with excessively strong edges to the central part of the kiln chamber 11, so that the aims of strengthening central air flow and reducing the central air flow are fulfilled. Through research, the curvatures of all points on the streamline smooth curved surface 13 are mainly influenced by the following three factors:

(1) the raw materials fired in the lime kiln comprise the following components in proportion: in the falling process of the raw materials 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 burnt in the lime kiln are limestone, and the main component is CaCO₃And MgCO₃However, the contraction ratios of the two compounds are different, so the component ratio of the raw materials can influence the heat flow distribution of the calcining zone in the kiln chamber 11, and further influence the curvature of the streamline smooth curved surface 13, CaCO₃The shrinkage ratio of (A) is slightly less than MgCO₃The shrinkage ratio of (2).

(2) Shape of the raw material: the pores among the spherical raw materials are larger, the resistance of heat flow passing through the raw materials is smaller, and the heat flow passing through the materials is strong, so that the kiln wall effect is smaller, the contraction degree of the streamline calcining zone is smaller, namely the corresponding curvature is smaller. After the sheet raw materials are stacked, 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 a calcining zone is larger, namely the corresponding curvature is larger.

(3) Pores resulting from calcination of the raw material:

the reaction of limestone during calcination is:

CaCO₃→CaO+CO₂

MgCO₃→MgO+CO₂

calcination decomposition of lump material to produce CO₂The dense blocky raw materials can be changed into loose and porous quicklime through gas, pores generated in the process can allow a small part of heat flow to pass through, the larger the pores of the quicklime are, the stronger the heat flow passing through the materials is, so that the kiln wall effect is smaller, and the shrinkage degree of a calcining zone is small and the corresponding curvature is small. Porosity is in turn influenced by a number of production parameter factors, such as temperature, pressure, limestone particle size, blast flow rate, etc.

In the above formula

Mainly showing CaCO in the raw material₃The influence of the contraction ratio on the curvature, in the above formula

Mainly represents MgCO in the raw material₃The influence of the contraction ratio on the curvature, in the above formula

Mainly comprisingShowing the influence of pores generated when the bulk raw material is calcined on the curvature, in the above formula

Mainly indicating 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 streamlined lime kiln is a flaky raw material, the K is 0.1; when the raw material of the streamline lime kiln is a spherical raw material, K is 0.02, and researches show that when the curvatures of all points on the streamline smooth curved surface 13 meet the formula, the heat flow intensity on each horizontal plane can be ensured to be uniform, further the calcination uniformity of the active lime is effectively ensured, and the product quality is effectively ensured.

Further, in the present embodiment, the positions of the streamline-shaped smooth curved surface 13 are the same as the positions 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. The limestone decomposition is only carried out in the calcining zone, so the heat flow outside the calcining zone has little influence on the product quality, and the calcining zone does not need to be streamlined.

When the specific position of the calcining zone is designed, the specific conditions of specific kiln type, capacity and the like need to be comprehensively considered so as to ensure better calcining effect. As a preferred embodiment, when the kiln type of the streamline lime kiln is a Martz double-hearth kiln or a sleeve kiln, the bottom end of the calcining belt is preferably located at the height of 1/3-1/4 of the height of the kiln body 1, namely the stop position of the calcining belt is preferably located at 1/3-1/4 of the height of the kiln body 1. When the kiln type of the streamline lime kiln is a beam type lime kiln, the kiln chamber 11 between the upper spray gun 4 and the position 0.5-4 m below the lower spray gun 5 partially forms the calcining zone, namely 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 lance 5 is the post calcining zone of the beam lime kiln, the position of which is selected in particular in dependence on the influence of the production conditions on the post calcining zone.

Further, when the kiln type of the streamline lime kiln is a milz 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 central 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 degree and less than or equal to 9 degrees, and the specific value is determined according to production conditions.

Further, the calcining zone is the area with the worst working environment in the kiln chamber 11 of the lime kiln, and has the highest temperature and the highest heat flow intensity. The refractory material 17 of the calcining zone is the area with the largest abrasion in the kiln chamber 11, and even burns red and burns through the kiln shell under special conditions, thereby causing safety accidents. Therefore, in order to reduce the probability of burning red and burning through the side wall of the kiln chamber 11 and reduce the accident rate, the wall thickness of the kiln body 1 corresponding to the position between the top end and the bottom end of the calcining zone is larger 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 both 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 a diameter gradually reduced downwards, and the wall thickness of the kiln body 1 corresponding to the bottom end of the conical surface 15 is larger than that of the kiln body 1 corresponding to the boundary of 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, the inner wall is in a streamline shape, and compared with a traditional straight lime kiln, the refractory amount of the calcining zone is increased, and a thick-wall calcining zone is formed. And the kiln wall thickness corresponding to the calcining zone is increased, which means that the kiln chamber 11 has better durability, the overhaul period of the kiln chamber 11 is prolonged, the equipment work rate can be improved, and the maintenance cost can be reduced. Meanwhile, the outer wall of the kiln body 1 adopting the part is in a zigzag shape, so that materials can be saved, and the cost is reduced.

Further, the streamline smooth curved surface 13 is formed by stacking refractory bricks 18 having different curvature of arc surface, as shown in fig. 9, one surface of the refractory brick 18 is a smooth arc surface 181, the other surfaces are rectangular, the curvature of the arc surface 181 of the refractory brick 18 is calculated according to the above-mentioned calculation formula of curvature, and the arc surfaces 181 of the plurality of refractory bricks 18 surround to form the streamline smooth curved surface 13.

During actual construction, the kiln body steel shell 16 is welded up ring by ring to form the required broken line type outer wall. And then, spraying a refractory material 17 in the kiln body steel shell 16, and welding a metal anchoring piece on the inner wall of the kiln body 1 in order to prevent the unshaped refractory material from falling off and enable the unshaped refractory material and the kiln body steel shell 16 to form a whole. After the anchoring parts are welded, surface dirt needs to be cleaned, sand is sprayed to the anchoring parts to prevent rust, then anchoring modes such as metal meshes and steel rings or Y-shaped nails and steel rings are adopted, the anchoring nails are alternated transversely and longitudinally, and the distance is set to be 100-250 mm according to actual conditions.

When the brick is built, the refractory bricks 18 are built layer by layer from the lateral center line of the kiln wall, and a thermal expansion joint is reserved during construction. If the curvature of the streamline kiln body 1 is too large and the stress of the kiln body steel shell 16 is too strong, a circle of steel structure support can be arranged along the central line at a corresponding height, and the steel structure support acts on a lower concrete platform through a support and is loaded by the concrete platform. The specific construction process is the prior art and is not described herein.

In conclusion, the streamlined 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 heat flow in the kiln chamber 11 is uniformly distributed, and the active lime is uniformly calcined; the edge airflow is small, the utilization rate of the heat energy of the lime kiln is high, 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 charge level collapse are reduced, the production of the lime kiln is stable, and the productivity is correspondingly increased;

(2) during processing, the size of the kiln body 1 corresponding to the cooling zone below the calcining zone can be kept unchanged, the size of the calcining zone is properly enlarged, and the volume of the calcining zone can be enlarged on the premise of not increasing the lower foundation of the streamline lime kiln, which means that the capacity of the lime kiln is improved. Compared with the traditional lime kiln, the streamlined lime kiln can increase the yield without increasing the foundation occupation area, and the capacity amplification can reach 25 percent.

(3) The wall thickness of the calcining zone is thicker than that of the preheating zone, and the thick-wall kiln chamber 11 with a 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 limekiln improves the kiln chamber of the traditional cylindrical straight-barrel limekiln into a streamline thick-wall kiln chamber 11 combining a zigzag external kiln shell and smooth curved inner wall bricklaying, optimizes the heat flow distribution in the kiln chamber 11, reduces the kiln wall effect, can reduce the production accident rate and prolong the service life of equipment. The quality fluctuation of the lime at the edge of the kiln wall and the lime at the center of the kiln chamber 11 is also controlled, the heat energy utilization rate of the lime kiln can be improved, and the energy conservation and emission reduction are realized. The capacity of the lime kiln can be improved on the premise of not increasing the occupied area of equipment. Meanwhile, the thick-wall kiln chamber 11 increases the thickness of refractory materials of the calcining zone, reduces the probability of red burning and burning through of the kiln chamber 11, and prolongs the period of overhaul of the lime kiln.

The above are merely exemplary embodiments of the present invention, and are not intended to limit the scope of the present invention. Any equivalent changes and modifications that can be made by one skilled in the art without departing from the spirit and principles of the invention should fall within the protection scope of the invention.

Claims

1. A streamline limekiln comprises a vertical kiln body with a kiln chamber, the kiln chamber is divided into a preheating zone, a calcining zone and a cooling zone from top to bottom, and is characterized in that,

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 greater than 0 and less than or equal to 1/3.

2. The streamlined lime kiln of claim 1,

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.

3. The streamlined lime kiln of claim 1,

the curvature of each point on the streamline smooth curved surface meets the following formula:

wherein C represents the sameThe curvature of a certain point on the streamline smooth curved surface, wherein beta percent represents CaCO in the raw materials fired in the streamline limekiln₃In proportion, 1-beta percent represents MgCO in the raw material fired in the streamline lime kiln₃In the ratio, H represents the vertical height of the calcining zone;

when the kiln type of the streamline lime kiln is a Maerz 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 an outer sleeve and the inner radius of an inner sleeve at the boundary of the preheating zone and the calcining zone;

ay represents the vertical distance between a point on the streamlined smooth surface and the tip of the calcining zone,

representing the true density of the raw material fired in the streamlined lime kiln,

and K is a coefficient, and represents the apparent density of the raw material fired in the streamline lime kiln.

4. The streamlined lime kiln of claim 3,

when the raw material of the streamline lime kiln is a flaky raw material, K is 0.1; when the raw material of the streamline lime kiln is a spherical raw material, K is 0.02.

5. The streamlined lime kiln of claim 1,

the kiln type of streamlined lime kiln is two thorax kilns of maltz or sleeve kiln, the height that the bottom of calcining zone was located is 1/3 ~ 1/4 of kiln body height.

6. The streamlined lime kiln of claim 1,

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 at an interval from top to bottom 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.

7. The streamlined lime kiln of claim 1,

the kiln type of the streamline lime kiln is a Maerz double-chamber kiln, the Maerz double-chamber kiln comprises two parallel kiln bodies, and the lower parts of the two kiln bodies are communicated through a pipeline; each upper portion of the kiln body is equipped with a plurality of spray guns along its circumference equal interval, there is the contained angle between the export direction of spray gun and the vertical direction.

8. The streamlined lime kiln of claim 7,

the included angle between the outlet direction of the spray gun and the vertical direction is larger than 0 degree and smaller than or equal to 9 degrees.

9. The streamlined lime kiln of claim 1,

the wall thickness of the kiln body corresponding to the position between the top end and the bottom end of the calcining zone is larger than that of the kiln body corresponding to the preheating zone.

10. The streamlined lime kiln of claim 9,

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 that of the kiln body corresponding to the boundary of the preheating zone and the calcining zone.