CN217005377U - Vertical annular preheating calcining kiln and rotary kiln calcining system for two-stage calcining - Google Patents
Vertical annular preheating calcining kiln and rotary kiln calcining system for two-stage calcining Download PDFInfo
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- CN217005377U CN217005377U CN202220747773.6U CN202220747773U CN217005377U CN 217005377 U CN217005377 U CN 217005377U CN 202220747773 U CN202220747773 U CN 202220747773U CN 217005377 U CN217005377 U CN 217005377U
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Abstract
The patent provides a vertical annular preheats calcining kiln, and it has the second grade combustor, is applied to cubic, the calcination of granular material for the productivity of rotary kiln improves by a wide margin, and the energy consumption of product reduces by a wide margin, reduces nitrogen oxide's production. The device comprises a shell body, an inner shell body, a material bearing bottom plate, a shell body formed by enclosing a closed connecting plate and a discharging device; the bottom of the outer shell is connected with a material bearing bottom plate, and the periphery of the closed connecting plate is connected with the inner shell; the outer shell and the inner shell enclose an annular cavity, and the top of the shell is provided with a feeding channel and a tail gas discharge channel which are communicated with the annular cavity; the center of the material bearing bottom plate is provided with an air inlet which is also a discharge opening; the driving mechanism of the discharging device is arranged outside the outer shell, the actuating mechanism of the discharging device extends into the kiln cavity between the upper part of the material bearing bottom plate and the lower end of the inner shell, the outlet of the secondary combustor arranged on the shell is communicated with the kiln cavity, and the inlet of the secondary combustor is connected with a fuel source or/and a high-temperature gas source.
Description
Technical Field
This patent relates to a vertical preheater and has a rotary kiln system of calcining that contains vertical preheater.
Background
The rotary kiln is widely applied to calcination of materials in cement, metallurgy and chemical industries, and the application history is over 130 years. The rotary kiln has a high feed end and a low discharge end, fuel is sprayed into the kiln from the discharge end for combustion, smoke and the material flow in the reverse direction, the rotary kiln rotates to enable the material to exchange heat with gas better so as to realize the purpose of calcination, the tail gas is directly discharged to the atmosphere at first, energy is wasted, a grate preheater, a cyclone preheater and the like are invented later, the waste heat of the tail gas of the rotary kiln is utilized to preheat the material, the energy consumption is reduced, the yield of the rotary kiln is improved, for cement calcination, an outside-kiln decomposing furnace is invented later, the fuel required by the whole production system is sprayed from the discharge end of the rotary kiln, and is sprayed into a decomposing furnace serving as a second combustion area for combustion, carbonate is mostly decomposed in the decomposing furnace, so that the process of decomposing limestone in the rotary kiln originally is completed before entering the rotary kiln, and the productivity of the rotary kiln is greatly improved, further reducing the calcination heat consumption of the cement clinker. The raw material for producing the cement clinker is in a powder shape.
Although a vertical preheater with a push head is widely used in rotary kilns for lump materials, particularly for lime production, a technology like a decomposing furnace for cement production does not exist for pre-calcining the materials in a second combustion area before the materials enter the rotary kiln, so that the heat consumption for calcining lime in the rotary kiln is high and the productivity is low.
1. In the existing 'preheater-rotary kiln-cooler' block granular material calcining system with the material granularity of more than or equal to 2mm, all fuels required by the whole system are sprayed from a burner at the kiln head of the rotary kiln, and the preheater only has the function of recovering and heating materials with limited waste heat of tail gas generated by the rotary kiln.
In the "preheater-kiln-cooler", the heat transfer capacity and efficiency of the rotary kiln are the lowest, especially for calcining lump limestone, the yield per unit volume of the rotary kiln is only less than 1.0t/d.m for year 1/4 of cement kiln. Because of the low output per unit volume, the heat loss of the equipment shells such as rotary kilns and the like per unit weight of products is large. Therefore, how to play the role of the preheater with relatively high heat exchange efficiency is the working direction of saving energy and improving productivity, for example, a new heat source is provided between a kiln tail feed inlet of the rotary kiln and a kiln tail induced draft fan, a new combustion device is additionally arranged, the decomposition rate or the pre-firing rate of materials entering the kiln is improved, and the yield of the rotary kiln can be greatly improved, but no report and actual use of related technologies exist at present. In the case of the conventional push-head vertical preheater, it has not been possible to achieve the object by allowing the preheater to assume a further pyrolysis function.
The vertical preheater of the head of pushing away that adopts usually has inside and outside barrel structure, and the material is arranged in the annular space at the bottom of the area support material that inside and outside barrel constitutes in, forms annular material layer, about the height of the material layer of joining in the heat exchange is generally 2.0m, and the flue gas that the rotary kiln discharged out rises and enters into annular material layer and carries out the heat exchange, and the material after being heated pushes away the head through hydraulic pressure and pushes the material into the rotary kiln in, and tail gas is then discharged from the top. The vertical preheaters with different specifications are configured according to the size of the rotary kiln, a plurality of push heads or even more than ten push heads can be arranged on the periphery of the outer barrel and correspondingly divided into a plurality of material storage chambers or even more than ten material storage chambers, heat exchange is carried out on flue gas in the storage chambers, the push heads push the materials into the rotary kiln alternately, and the push heads reciprocate.
Although the vertical preheater is large in overall dimension, the actually stored material amount is not large, the resistance between a material layer and the whole system device is large, the height of the material layer is low, the heat exchange time between the material and the flue gas is not sufficient, the temperature of the discharged waste gas is still high, the heat energy utilization rate is not high, in addition, the material is entrained by the reciprocating motion of the pushing head to generate the material leakage phenomenon, a plurality of material collecting pipes and hoppers for bearing the material leakage need to be arranged, the material leakage is manually treated, obviously, the air tightness is also poor, more air is leaked, and the actual temperature of the heat exchange flue gas is reduced.
2. A 'preheater-rotary kiln-cooler' calcining block granular material system is particularly suitable for a rotary kiln calcining system for ores with the material granularity of 15mm-40mm, such as limestone, dolomite, bauxite, pellet ore, metal ore, building ceramsite and the like, has the characteristics of uniform material heating and uniform kiln product quality, and a production process line generally comprises a raw material feeding system, a preheater system, a rotary kiln, a cooler system, a rotary kiln burner system, a smoke induced draft fan and other main equipment, wherein the cooler-rotary kiln-vertical preheater-dust remover-smoke induced draft fan-chimney are sequentially connected in series according to the gas flow direction; according to the material flow direction, a raw material feeding system, a preheater, a high-temperature material feeding device, a rotary kiln and a cooler are sequentially connected in series; an included angle is formed between the axis of the rotary kiln cylinder and the horizontal plane, the sine value sin alpha or the tangent value tan alpha of the general included angle is 3.5%, the feed end is high, the discharge end is low, and the fuel is sprayed into the kiln from the discharge end of the rotary kiln to be combusted. The preheater has the main functions of preheating the material by utilizing the waste heat of the high-temperature flue gas, so that the temperature of the material entering the rotary kiln is increased, the heat load of the rotary kiln is reduced, and partial heat is recovered, and the preheater is a physical process; the vertical preheater is generally adopted for calcining limestone/dolomite, the chain grate type preheater is generally adopted for calcining pellets, the rotary preheater is generally adopted for calcining ceramsite, and no preheating device is adopted for ultrahigh-temperature reburning small granular magnesite and dolomite. The rotary kiln having the function of holding the material higher than in the preheaterCalcining at a temperature to perform physical and chemical reactions to produce a product; the main function of the cooler is to cool the product produced by the rotary kiln, so as to facilitate transportation, storage and heat recovery, usually in an air cooling mode, the air after heat exchange enters the rotary kiln to support combustion, and some of the coolers adopt rapid cooling for controlling the crystal form of the calcined material, such as a direct water bath mode. However, it is known that the heat exchange efficiency of the materials in the rotary kiln is low, the unit volume output is low, the heat dissipation loss of the rotary kiln cylinder is large, the energy consumption of the products per unit weight is high, and NO in the flue gas generated by combustion is lowXHigh concentration, exceeding the environmental protection control standard.
3. The end of the kiln head of the rotary kiln is usually provided with a heat-resistant steel guard plate for a long time, so that the refractory material is prevented from being loosened due to downward stringing, but the guard plate made of the heat-resistant steel in practical application is easy to be burnt at high temperature, corroded by smoke and broken to lose efficacy. Once the kiln mouth guard plate fails, the kiln mouth barrel can be damaged, the kiln mouth barrel becomes a horn shape, and the service life of kiln mouth refractory bricks or refractory castable can be influenced. The heat-resistant steel protective plates are usually replaced within 2 years, some heat-resistant steel protective plates even have the service life of only 2-3 months, a set of heat-resistant steel protective plates are tens of thousands of yuan in a small kiln, 20-30 thousands of yuan in a larger kiln, the production stopping and maintenance delay time is delayed, and the problems that a rotary kiln cylinder body deforms and an explosion opening is flared are difficult to overcome. Due to the damage of the protective plate, the sealing devices at the kiln head and the kiln tail connected with the protective plate also lose effectiveness, and the conditions of ash emission and air leakage often occur.
The heat exchange and movement conditions of other block granular materials except limestone in the rotary kiln are similar.
Therefore, how to increase the output per unit volume or the output per unit cross-sectional area of the rotary kiln is a key problem of reducing heat consumption.
4. In the system for calcining the granular materials of the preheater-rotary kiln-cooler block, because the flame temperature generated by the burner of the rotary kiln is high, a large amount of NO is necessarily generatedXAnd the atmospheric environment is polluted.
However, in the case of the vertical preheater-rotary kiln-vertical cooler calcining system for calcining limestone, dolomite and the like, the vertical preheater of the divided push rod type is mostly used, and the vertical preheater is disposed between the preheater and the preheaterThe flue gas is in the temperature area of 800-XThe existing calcining system of the chamber push rod vertical preheater, the rotary kiln and the vertical cooler for calcining limestone, dolomite and the like does not have the condition of fully completing mixing and reduction reaction in enough space and time, and does not have the condition of installing a reducing agent spray nozzle, so that the existing calcining system of the chamber push rod vertical preheater, the rotary kiln and the vertical cooler for calcining limestone, dolomite and the like does not have the condition of adopting an SNCR (selective catalytic reduction) process for denitration, only can consider that after heat exchange is completed between flue gas and materials in the preheater, a selective catalytic reduction technology process, namely SCR denitration is adopted, the temperature of the discharged flue gas also needs to be controlled in a proper interval, but the investment is large, the operating cost is high, enterprises are difficult to bear, and therefore, at present, a denitration device is not basically adopted in industries of calcining limestone, dolomite, bauxite and the like.
5. For the calcination of materials with the particle size of 2-15mm, particularly for the ultra-high temperature calcination, the particle size range is embarrassed, and the particle size range is too large to be suspended and cannot adapt to the condition when the particle size range is used as a cyclone or suspension preheater similar to a cement kiln; as a vertical preheater with a pushing head similar to lime production, the vertical preheater cannot be adapted because the particles are too small and the resistance is very large. Such as limestone or dolomite mines, there is essentially no way for 2-15mm ore to be used to calcine lime.
For 2-15mm dolomite/magnesite ultrahigh-temperature magnesia-calcium sand, a preheater technology does not exist internationally at present, the length of a rotary kiln can be only lengthened by 2-3 times that of a common rotary kiln with a preheater, but the final exhaust gas emission temperature is still over 600 ℃, and the heat consumption is 2-3 times that of common light-burned dolomite. The higher the calcination temperature, the higher the NO produced by the flue gasXThe more, the tail gas temperature is lower than the denitration process of SNCR although it is high.
The ironmaking pellets are calcined by a grate-rotary kiln, so that the system has the advantages of large occupied area, more matched equipment, high investment, low thermal efficiency, higher failure rate and high operation cost.
The ceramsite is calcined by adopting a two-stage or three-stage rotary kiln, and compared with the rotary kiln, the energy consumption is higher.
Disclosure of Invention
The patent aims at providing a vertical annular preheating calcining kiln which is provided with a secondary combustor and is applied to calcining massive and granular materials, particularly lime, so that the production capacity of the rotary kiln is greatly improved, the energy consumption of products is greatly reduced, and the generation of nitrogen oxides is reduced.
In order to achieve the purpose, the vertical annular preheating calcining kiln comprises a shell, an inner shell, a material bearing bottom plate, a shell enclosed by a closed connecting plate and a discharging device; the outer shell and the inner shell are of vertical polygonal or circular structures, the bottom of the outer shell is connected with a material bearing bottom plate, and the periphery of a closed connecting plate is connected with the inner shell and is higher than or equal to the lower end of the inner shell; the outer shell and the inner shell enclose an annular cavity, and the top of the shell is provided with a feeding channel and a tail gas discharge channel which are communicated with the annular cavity; the center of the material bearing bottom plate is provided with an air inlet which is also a discharge opening; the driving mechanism of the discharging device is arranged outside the outer shell, the actuating mechanism of the discharging device extends into the kiln cavity between the upper part of the material bearing bottom plate and the lower end of the inner shell, and the material is added into the annular cavity through the feeding channel and is carried by the material bearing bottom plate; when the actuating mechanism of the discharging device does not act, the material is kept standing in the kiln cavity, and when the actuating mechanism of the discharging device acts, the material is discharged through the discharging port; the outlet of the secondary combustor arranged on the shell is communicated with the kiln cavity, and the inlet of the secondary combustor is connected with a fuel source or/and a high-temperature gas source.
The vertical annular preheating calcining kiln is provided with a secondary combustion chamber which can not be reached by materials in a kiln cavity, and an outlet of the secondary combustor is communicated with the secondary combustion chamber.
In the vertical annular preheating calcining kiln, a secondary combustion chamber is formed between the lower part of the closed connecting plate and the inner shell; the inner shell body at the lower part of the closed connecting plate is made of heat-resistant steel materials or is of a hollow structure, and ventilation or cooling medium cooling is carried out inside the inner shell body of the hollow structure.
The secondary burner (or called burner) is installed on the closed connecting plate, and the outlet of the secondary burner is communicated with the secondary combustion chamber.
And combustion-supporting air is introduced into the secondary combustion chamber through a pipeline or a combustion-supporting air channel in the combustor, or cooling air obtained by cooling the inner shell of the hollow structure is introduced into the secondary combustion chamber.
In the vertical annular preheating calcining kiln, the annular cavity body is internally provided with the guide bridges at intervals along the circumferential direction, and the lower parts of the guide bridges form a secondary combustion chamber.
In the annular cavity, a guide bridge is connected between the outer shell and the inner shell, materials above the guide bridge are blocked by the guide bridge to change the passing direction, the materials go down from two sides of the guide bridge, a channel for the circulation of the materials and air flow is arranged between two adjacent guide bridges, an outlet of a secondary combustor or/and a nozzle outlet of a denitration device are/is communicated with a secondary combustion chamber, and the secondary combustor or/and the denitration device are/is arranged on the shell of the vertical annular preheating calcining kiln. The quantity of the material guiding bridge and the secondary combustion chamber is set according to the circumference of the annular cavity.
In the vertical annular preheating calcining kiln, the combustion-supporting air is introduced into the secondary combustion chamber through the secondary combustor or an independent air channel.
In the vertical annular preheating calcining kiln, the side of the top/upper part of the annular cavity close to the outer shell is connected with the tail gas discharge channel, and the side close to the inner shell is connected with the feeding channel; the outlet height of the feeding channel can be adjusted up and down or fixed.
In the vertical annular preheating calcining kiln, the actuating mechanism of the discharging device is a pushing head which does reciprocating motion, or a helical blade or a blade which does rotary motion, or a blade which does swing motion.
The patent simultaneously provides a rotary kiln system of calcining of two-stage that reduces NOx formation volume, increases rotary kiln system's output, energy resource consumption is few.
The rotary kiln calcining system for two-stage calcining comprises a rotary kiln system, a primary burner system, the vertical annular preheating calcining kiln, a cooler system, a raw material feeding system, a finished product discharging system and a tail gas treatment system; according to the material flow, a raw material feeding system, a vertical annular preheating calcining kiln, a rotary kiln system, a cooler system and a finished product discharging system are sequentially connected in series; according to the combustion gas flow, a primary combustor system, a rotary kiln system, a vertical annular preheating calcining kiln and a tail gas treatment system are sequentially connected in series; the primary burner system provides a heat source for the rotary kiln, and fuel of the primary burner system is sprayed into the rotary kiln from the discharge end of the rotary kiln.
In the rotary kiln calcining system for two-stage calcining, the discharge opening of the vertical annular preheating calcining kiln is connected with the feed inlet of the rotary kiln through the connecting channel, the discharge opening of the vertical annular preheating calcining kiln is higher than the feed inlet of the rotary kiln, flue gas generated by the rotary kiln enters the vertical annular preheating calcining kiln through the connecting channel to exchange heat with materials and then enters the tail gas treatment system through the tail gas discharge channel, and the tail gas treatment system is provided with the induced draft fan; the materials are added into the annular cavity from the raw material feeding system through a feeding channel at the top of the vertical annular preheating calcining kiln, and after heat exchange with high-temperature flue gas, the materials are output to a discharge opening by a discharging device and are added into the rotary kiln through a connecting channel; the outlet of the secondary burner arranged on the connecting channel is communicated with the connecting channel.
The connecting channel is also called transfer groove and kiln tail smoke chamber. High-temperature gas generated in the connecting channel enters the kiln cavity through the connecting channel to exchange heat with the material.
The rotary kiln calcining system for the two-stage calcining further comprises a second-stage combustion chamber, a gas outlet of the second-stage combustion chamber is communicated with the connecting channel, and an outlet of the second-stage combustor is located in the second-stage combustion chamber.
High-temperature gas from the secondary combustor enters the kiln cavity through the connecting channel to exchange heat with the materials.
In the rotary kiln calcining system for two-stage calcining, the temperature of the secondary combustion chamber is controlled to be 800-; or, the temperature of the connecting channel is controlled to be 800-.
The beneficial effect of this patent:
1. compared with the preheater in the prior art, due to the establishment of the secondary calcination, the thermal technology of the original block material preheater-rotary kiln-cooler calcination system is greatly changed, the heat generated by the secondary combustor increases the heat in the vertical annular preheating calcination kiln or/and improves the temperature in the vertical annular preheating calcination kiln, so that the partial calcination of the material in the vertical annular preheating calcination kiln is completed, the material amount entering the rotary kiln can be increased, and under the condition that the primary combustor at the kiln head provides the same thermal strength, the yield of the rotary kiln and the whole calcination system can be greatly increased, for example, the production technology of lime calcined from limestone can be realized, and the limestone can be greatly decomposed in front of the feed inlet of the rotary kiln or/and the vertical annular preheating calcination kiln, so that the capacity of the rotary kiln is increased.
Because of the establishment of the secondary calcination, the vertical annular preheating calcining kiln is a shaft furnace for calcining materials, or is called as a vertical annular preheating calcining furnace, and simultaneously, the waste heat of the gas discharged by the rotary kiln is utilized to preheat the materials to save energy, and the vertical annular preheating calcining kiln is also a vertical preheater.
2. Because the heat exchange efficiency of the rotary kiln is lower than that of the vertical annular preheating calcining kiln, the heat dissipation loss of the cylinder body of the rotary kiln is higher than that of the vertical annular preheating calcining kiln, the heat preservation performance of the vertical annular preheating calcining kiln is also better than that of the rotary kiln, the heat dissipation losses of the cylinder bodies of the vertical annular preheating calcining kiln, the rotary kiln and other thermal equipment are relatively fixed and basically not increased along with the increase of the yield, and therefore, the energy consumption of products can be greatly reduced after the yield of the whole calcining system is increased.
3. Because the flame temperature generated by the primary burner of the kiln head of the rotary kiln is high, the amount of the generated thermal NOx is high, and the combustion environment of the secondary burner enables the flame temperature to be controlled in a relatively low interval, the amount of the generated thermal NOx is low, so that the NOx generation amount of the whole calcining system is greatly reduced.
4. Because the outlet height of the feeding channel of the vertical annular preheating calcining kiln can be adjusted up and down or fixed, the height of the material layer in the cavity of the kiln can be adjusted and controlled, and the resistance of the material layer to gas can be adjusted and controlled, so that the vertical annular preheating calcining kiln can adapt to materials with different particle sizes.
5. Compared with the traditional push rod type vertical preheater, the spiral discharging device is adopted, so that the sealing performance of the vertical annular preheating calcining kiln is improved, and the phenomena of material carrying and air leakage are avoided.
6. Because the position setting of vertical annular preheating calcining kiln's feed channel and exhaust emission passageway more is favorable to the heat exchange effect of high temperature gas and material and the homogeneity of being heated, is favorable to reducing the resistance of material to gas.
7. The spray head of the denitration device of the SNCR method arranged in the connecting channel or/and the secondary combustion chamber can reduce the investment and the operating cost of the flue gas denitration device of the production line.
8. Because the annular sleeve type vertical cooler is adopted, the materials are uniformly distributed in the cooler, the resistance of the materials to cooling air is uniformly distributed, the cooling air is uniformly distributed in the cooler, the heat exchange effect of the cooling air and the materials is uniform, the flow of combustion-supporting air entering the rotary kiln is stable, and the annular sleeve type vertical cooler plays an important role in stabilizing combustion in the rotary kiln.
9. Because of the establishment of the two-stage calcination, the thermal technology of the original block material preheater-rotary kiln-cooler calcination system is greatly improved, the calcination rate of the material before entering the rotary kiln is greatly improved, the calcination time of the material in the rotary kiln can be shortened, and the length of the rotary kiln can be correspondingly shortened.
10. The invention can also be used independently as a vertical annular calcining vertical kiln. When the vertical annular calcining vertical kiln is used independently, various cooling devices can be connected below the discharge opening to cool calcined materials, and the cooling devices can be integrated with the vertical annular calcining vertical kiln or can be arranged separately. When the vertical annular calcining vertical kiln is used independently, a rotary kiln calcining system is not required to be connected.
Drawings
Fig. 1 is a schematic view of a rotary kiln calcination system for two-stage calcination of example 1.
Fig. 2 is a plan view of the second secondary combustor and the denitrator nozzle, etc. of fig. 1, which extend into the second secondary combustion chamber.
Figure 3 is a schematic view of a vertical annular preheat calciner of example 2.
Fig. 4 is a plan view of the second secondary combustor and the denitrator nozzle, etc. of fig. 3 extending into the second secondary combustion chamber.
FIG. 5 is a schematic view of a vertical ring-shaped preheating calciner or the like according to example 3.
Fig. 6 is a schematic view of a vertical annular preheat calciner or the like of example 4.
Fig. 7 is a schematic view of a vertical annular preheat calciner or the like of example 5.
FIG. 8 is a schematic view of a vertical ring-shaped preheating calciner or the like according to example 6.
Fig. 9 is a schematic view of a vertical annular preheat calciner or the like of example 7.
In the figure, a raw material feeding system 100, a rotary kiln system 200, a cooler system 300, a finished product discharging system 400, a primary combustor system 500, a tail gas treatment system 600, a dust remover 601, an induced draft fan 602,
a vertical annular preheating calcining kiln 1, an annular cavity 11, a feeding channel 12, a tail gas discharge channel 13, an outer shell 15, an inner shell 16, a material bearing bottom plate 17, a closed connecting plate 18 and a hollow structure 19,
a first secondary combustion chamber 21, a second secondary combustion chamber 22, a third secondary combustion chamber 23, a first secondary combustor 24, a second secondary combustor 25, a third secondary combustor 26,
the discharging device 3, the pushing head 31, the helical blade 32,
denitration device shower nozzle 4, connecting channel 5, guide bridge 6.
Detailed Description
Example 1:
referring to the rotary kiln calcination system for two-stage calcination shown in fig. 1 and 2, according to the material flow, a raw material feeding system 100, a vertical annular preheating calcination kiln 1, a rotary kiln system 200, a cooler system 300 and a finished product discharging system 400 are connected in series in sequence; according to the flow of combustion gas, the primary burner system 500, the rotary kiln system 200, the vertical annular preheating calcining kiln 1 and the tail gas treatment system 600 are sequentially connected in series. The primary burner system provides a heat source for the rotary kiln, and fuel of the primary burner system is sprayed into the rotary kiln from the discharge end of the rotary kiln.
The discharge opening of the vertical annular preheating calcining kiln is connected with the feed inlet of the rotary kiln through a connecting channel 5 (the connecting channel is also called a transfer groove and a kiln tail smoke chamber), the discharge opening of the vertical annular preheating calcining kiln is higher than the feed inlet of the rotary kiln, smoke generated by the rotary kiln enters the vertical annular preheating calcining kiln through the connecting channel to exchange heat with materials and then enters a tail gas treatment system through a tail gas discharge channel, and the tail gas treatment system is provided with a dust remover 601, an induced draft fan 602 and the like.
The vertical annular preheating calcining kiln 1 comprises a shell body enclosed by an outer shell body 15, an inner shell body 16, a material bearing bottom plate 17 and a closed connecting plate 18, and a discharging device 3. The outer shell and the inner shell are of vertical polygonal or circular structures, the outer shell and the inner shell enclose an annular cavity 11, and the top of the shell is provided with a feeding channel 12 and a tail gas discharge channel 13 which are communicated with the annular cavity. The exhaust gas discharge channel 13 is adjacent to the outer shell side and the feed channel 12 is adjacent to the inner shell side. The outlet height of the feed channel can be adjusted up and down or fixed.
The bottom of the outer shell 15 is connected with a material bearing bottom plate 17, and the center of the material bearing bottom plate 17 is provided with an air inlet which is also a discharge opening.
The material is added into the annular cavity 11 from the raw material feeding system 100 through the feeding channel 12 at the top of the vertical annular preheating calcining kiln, and after heat exchange with high-temperature flue gas, the material is output to the discharge opening by the discharging device 3 and enters the rotary kiln through the connecting channel. The driving mechanism of the discharging device 3 is arranged outside the outer shell, the actuating mechanism of the discharging device extends into the kiln cavity between the upper part of the material bearing bottom plate and the lower end of the inner shell, and the material is added into the annular cavity through the feeding channel and is carried by the material bearing bottom plate; when the actuating mechanism of the discharging device does not act, the material is kept standing in the kiln cavity, and when the actuating mechanism of the discharging device acts, the material enters the feeding end of the rotary kiln through the discharging port and the connecting channel 5.
The periphery of the closed web 18 is connected to the upper end of the inner casing, or the closed web 18 is higher than the lower end of the inner casing 16 (see fig. 9), and a secondary combustion chamber 21, which cannot be reached by the material, is formed between the lower portion of the closed web and the inner casing. A first secondary burner (or burner) 24 is mounted on the closed web 18. And the outlet of the first secondary combustor is positioned in the first secondary combustion chamber.
The inner shell 16, which encloses the lower part of the web, has a hollow structure 19 which is open to the atmosphere and inside which a ventilation or cooling medium is cooled. And combustion-supporting air is introduced into the first secondary combustion chamber through a pipeline or a combustion-supporting air channel of the first secondary combustor, or cooling air obtained by cooling the inner shell of the hollow structure is introduced into the first secondary combustion chamber.
The outlet of the second-stage combustor 25 or/and the nozzle outlet of the denitration device are/is communicated with the annular cavity 11, and the second-stage combustor or/and the nozzle 4 of the denitration device are/is arranged on the vertical annular preheating calcining kiln shell. If the denitration device nozzle 4 is arranged on the shell of the vertical annular preheating calcining kiln, the temperature of the annular cavity 11 is controlled to be 800-1100 ℃.
The gas outlet of the second-stage combustion chamber III 23 is communicated with the connecting channel 5, and the outlet of the second-stage combustor III 26 is positioned in the second-stage combustion chamber III. And high-temperature gas from the third secondary combustor 26 enters the kiln cavity through the connecting channel to exchange heat with the material.
If the spray head 4 of the SNCR denitration device is arranged on the connecting channel, the temperature of the connecting channel is controlled to be 800-.
Inlets of the first secondary combustor 24, the second secondary combustor 25 and the third secondary combustor 26 are connected with a fuel source or/and a high-temperature gas source.
Example 2:
referring to fig. 3 and 4, the vertical annular preheating calcining kiln is mainly different from the vertical annular preheating calcining kiln of the embodiment 1 in that: connect guide bridge 6 between outer casing and interior casing, guide bridge 6 sets up along annular cavity circumference interval, and the material of guide bridge top is blockked and changes current direction by the guide bridge, descends from the both sides of guide bridge, is the passageway of material and air current circulation between two adjacent guide bridges, and the below of guide bridge forms second grade combustion chamber two 22. The number of the material guiding bridge and the number of the second-stage combustion chambers are set according to the circumference of the annular cavity; and the outlet of the second-stage combustor 25 or/and the nozzle outlet of the denitration device are/is communicated with the second-stage combustion chamber 22. The material guiding bridge 6 can be composed of an upper refractory plate and a lower refractory plate with an air interlayer in the middle.
Example 3:
referring to fig. 5, a vertical annular preheating calciner is shown, which is mainly different from the vertical annular preheating calciner of example 2 in that: the closed connecting plate 18 is connected with the lower end of the inner shell, and an opening communicated with the atmosphere is formed between the upper part of the closed connecting plate and the inner shell; the inner side of inner shell 16 is protected by refractory material; in this embodiment 3, the parts of the second-stage combustion chamber 21, the second-stage combustor 24, the denitrator showerhead extending into the second-stage combustion chamber 22, and the second-stage combustor 25 in embodiment 2 are not included.
Example 4:
referring to fig. 6, a vertical annular preheat calciner is illustrated, which differs from the vertical annular preheat calciner of example 2 primarily in that: in example 4, the parts of the second stage combustion chamber three 23, the second stage burner three 26, the denitrator nozzle extending into the belt connecting passage, the denitrator nozzle extending into the second stage combustion chamber two, the second stage burner two 25, and the like in example 2 were omitted.
Example 5:
referring to fig. 7, a vertical annular preheating calciner is shown, which is mainly different from the vertical annular preheating calciner of example 3 in that: in example 5, the denitration device nozzle 4 and the second stage burner 25 which protrude into the second stage combustion chamber 22 are added, but the denitration device nozzle 23, the third stage burner 26, and the denitration device nozzle which protrudes into the belt connecting passage in example 3 are not included.
Example 6:
referring to fig. 8, a vertical annular preheat calciner is illustrated, which differs from the vertical annular preheat calciner of example 5 primarily in that: in the embodiment 6, the material guide bridge 6 in the embodiment 5 is not arranged, and the outlet of the denitration device spray head 4 and the outlet of the second-stage combustor 25 are directly communicated with the annular cavity 11.
Example 7:
referring to fig. 9, a vertical annular preheating calciner is shown, which is mainly different from the vertical annular preheating calciner of example 2 in that: closed web 18 is elevated above the lower end of inner housing 16.
In each embodiment, the actuator of the discharging device 3 is a pushing head 31 which performs reciprocating motion, or the actuator of the discharging device is a helical blade 32 or a paddle which performs rotary motion or swinging motion.
The beneficial effect of this technique:
compared with the preheater in the prior art, the temperature is improved by the heat generated by the secondary combustor due to the establishment of the secondary calcination, so that the partial calcination of the materials is completed in the vertical annular preheating calcining kiln, and the material quantity entering the rotary kiln can be increased; for example, the carbonate of limestone can be largely decomposed above 900 ℃, and the yield of the rotary kiln and the system can be largely increased under the condition that the primary combustor at the kiln head of the rotary kiln provides the same thermal strength.
2 because the heat exchange efficiency of the rotary kiln is lower than that of the vertical annular preheating calcining kiln, the heat dissipation loss of the rotary kiln barrel is higher than that of the vertical annular preheating calcining kiln, the heat preservation performance of the vertical annular preheating calcining kiln is higher than that of the rotary kiln, the heat dissipation losses of the vertical annular preheating calcining kiln, the rotary kiln and other thermal equipment barrels are relatively fixed and do not increase along with the increase of the yield, and therefore the energy consumption can be greatly reduced after the yield of the system is improved.
3 because the flame temperature generated by the primary burner of the kiln head of the rotary kiln is high, the amount of the generated thermal NOx is high, and the combustion environment of the secondary burner enables the flame temperature to be controlled in a relatively low interval, the amount of the generated thermal NOx is low, so that the generation amount of the NOx of the whole calcining system is greatly reduced.
4. Compared with the traditional push rod type vertical preheater, the spiral or blade type discharging device is adopted, so that the sealing performance of the vertical annular preheating calcining kiln is improved, and the phenomena of material carrying and air leakage are avoided.
Claims (10)
1. The vertical annular preheating calcining kiln comprises a shell body, an inner shell body, a shell body formed by enclosing a material bearing bottom plate and a closed connecting plate, and a discharging device; the method is characterized in that: the outer shell and the inner shell are of vertical polygonal or circular structures, the bottom of the outer shell is connected with a material bearing bottom plate, and the periphery of a closed connecting plate is connected with the inner shell and is higher than or equal to the lower end of the inner shell; the outer shell and the inner shell enclose an annular cavity, and the top of the shell is provided with a feeding channel and a tail gas discharge channel which are communicated with the annular cavity; the center of the material bearing bottom plate is provided with an air inlet which is also a discharge opening; the driving mechanism of the discharging device is arranged outside the outer shell, the actuating mechanism of the discharging device extends into the kiln cavity between the upper part of the material bearing bottom plate and the lower end of the inner shell, and the material is added into the annular cavity through the feeding channel and is carried by the material bearing bottom plate; when the actuating mechanism of the discharging device does not act, the material is kept standing in the kiln cavity, and when the actuating mechanism of the discharging device acts, the material is discharged through the discharging port; the outlet of the secondary combustor arranged on the shell is communicated with the kiln cavity, and the inlet of the secondary combustor is connected with a fuel source or/and a high-temperature gas source.
2. The vertical annular preheat calciner of claim 1, wherein: a secondary combustion chamber which can not be reached by the materials is arranged in the kiln cavity, and an outlet of the secondary combustor is communicated with the secondary combustion chamber.
3. The vertical annular preheat calciner of claim 2, wherein: a secondary combustion chamber is formed between the lower part of the closed connecting plate and the inner shell; the inner shell body at the lower part of the closed connecting plate is made of heat-resistant steel materials or is of a hollow structure, and ventilation or cooling medium cooling is carried out inside the inner shell body of the hollow structure.
4. A vertical annular preheat calciner according to claim 2, characterised in that: and material guide bridges are arranged in the annular cavity body at intervals along the circumferential direction, and a secondary combustion chamber is formed below the material guide bridges.
5. The vertical annular preheat calciner of claim 1, wherein: the top/upper part of the annular cavity is connected with an exhaust gas discharge channel close to the outer shell side, and is connected with a feeding channel close to the inner shell side; the outlet height of the feeding channel can be adjusted up and down or fixed.
6. The vertical annular preheat calciner according to claim 1, wherein: the actuating mechanism of the discharging device is a pushing head which does reciprocating motion, or a helical blade or a blade which does rotary motion, or a blade which does swing motion.
7. The rotary kiln calcining system for two-stage calcining is characterized by comprising a rotary kiln system, a primary burner system, the vertical annular preheating calcining kiln as claimed in claim 1, a cooler system, a raw material feeding system, a finished product discharging system and a tail gas treatment system; according to the material flow, a raw material feeding system, a vertical annular preheating calcining kiln, a rotary kiln system, a cooler system and a finished product discharging system are sequentially connected in series; according to the combustion gas flow, a primary combustor system, a rotary kiln system, a vertical annular preheating calcining kiln and a tail gas treatment system are sequentially connected in series; the primary burner system provides a heat source for the rotary kiln, and fuel of the primary burner system is sprayed into the rotary kiln from the discharge end of the rotary kiln.
8. The rotary kiln calcination system for two-stage calcination according to claim 7, wherein the discharge port of the vertical annular preheat calciner is connected to the feed inlet of the rotary kiln through a connecting passage, the discharge port of the vertical annular preheat calciner is located higher than the feed inlet of the rotary kiln, flue gas generated by the rotary kiln enters the vertical annular preheat calciner through the connecting passage to exchange heat with the material and then enters the tail gas treatment system through the tail gas discharge passage, and the tail gas treatment system is provided with an induced draft fan; the materials are added into the annular cavity from the raw material feeding system through a feeding channel at the top of the vertical annular preheating calcining kiln, and after heat exchange with high-temperature flue gas, the materials are output to a discharge opening by a discharging device and are added into the rotary kiln through a connecting channel; the outlet of the secondary burner arranged on the connecting channel is communicated with the connecting channel.
9. The rotary kiln calcination system for two-stage calcination according to claim 8, further comprising a secondary combustion chamber, the gas outlet of the secondary combustion chamber being communicated with the connecting passage, the outlet of the secondary burner being located in the secondary combustion chamber.
10. The rotary kiln calcination system for two-stage calcination according to claim 7, characterized in that: the temperature of the secondary combustion chamber is controlled to be 800-; or, the temperature of the connecting channel is controlled to be 800-.
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| CN202220747773.6U CN217005377U (en) | 2022-04-01 | 2022-04-01 | Vertical annular preheating calcining kiln and rotary kiln calcining system for two-stage calcining |
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Cited By (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN117516182A (en) * | 2023-11-27 | 2024-02-06 | 常州市范群干燥设备有限公司 | Preheating device and preheating method for roasting rotary kiln |
| CN117516182B (en) * | 2023-11-27 | 2024-05-17 | 常州市范群干燥设备有限公司 | Preheating device and preheating method for roasting rotary kiln |
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2022
- 2022-04-01 CN CN202220747773.6U patent/CN217005377U/en active Active
Cited By (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN117516182A (en) * | 2023-11-27 | 2024-02-06 | 常州市范群干燥设备有限公司 | Preheating device and preheating method for roasting rotary kiln |
| CN117516182B (en) * | 2023-11-27 | 2024-05-17 | 常州市范群干燥设备有限公司 | Preheating device and preheating method for roasting rotary kiln |
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