Center burner lime kiln and active lime roasting production process

Abstract

The invention discloses a center burner lime kiln and an active lime roasting production process, can also be used for a drying process of granular materials or a roasting process of active magnesia and refractory materials, and is an upgrade of a large low-calorific-value gas TGS lime kiln. The method comprises the steps that a variable-speed spiral distributing device and a multi-pipe distributing device are adopted for conducting two-time distributing on a furnace top bin and a furnace throat respectively, and improvement of a sealed discharging structure, a furnace bottom sealed bearing structure, the inner shape of a ten-section type blast furnace dumbbell-shaped furnace body, a large-scale air-cooling combined type center burner and a side burner is achieved; the sealing structure is used for improving the uniformity of material flow, air flow and temperature distribution, improving the strength of the sealing structure, enhancing the resistance of the TGS lime kiln to poor grain size distribution and even burst raw materials, improving the production index and the environment-friendly state and reducing the production cost.

Description

Technical Field

[0001] The present invention relates to the technical field of lime kilns, and particularly to a central burner lime kiln and an active lime roasting production process. Background Art

[0002] With the promotion of energy conservation, emission reduction and carbon reduction in the iron and steel industry, large-scale pellet smelting has become a hot topic in the industry. Since pellet production must use high-calorific value gas, high-calorific value gases such as coke oven gas, natural gas and even converter gas have become further scarce.

[0003] Most of the current excellent lime production processes in the lime industry are original patented technologies of foreign enterprises, using natural gas or pulverized coal as fuel, and have developed and gradually formed a lime roasting theory of high-calorific value fuel and high-temperature rapid firing. Representative processes are as follows: (1) The patented technology represented by the Fokas shaft kiln arranges multiple combustion beams in the furnace, improving the uniformity of gas flow distribution and heat supply. However, since the combustion beams are in the flame and roasting material layer, they need to withstand severe charging impact, abrasion and high temperature, so complex oil cooling or expensive heat-resistant alloys need to be used, and the service life is still quite low. Its heat dissipation loss is large, and the investment, maintenance cost and production cost are all relatively high.

[0004] (2) The patented technology represented by the Maerz kiln uses two furnaces, achieving countercurrent roasting and regenerative energy recovery, improving product quality and energy utilization rate. However, the threat of blockage and service life of its bridging channel to production is quite high, and the requirements for raw material particle size and explosiveness are quite strict. In addition, since the cooling air does not participate in combustion, the exhaust gas volume and oxygen content in the exhaust gas are increased, which is not conducive to the recovery of CO2.

[0005] (3) The patented technologies represented by the sleeve kiln and the inner-guided lime shaft kiln (ZL98213196.8) set an inner cylinder or an inner-guided furnace core in the center of the shaft furnace, and correspondingly set a high-temperature fire bridge (hanging arch bridge). Although partial countercurrent calcination is achieved, the inner cylinder, furnace core and fire bridge all withstand abrasion and high temperature, the brick type is complex, and the service life is short. The investment and production cost are also quite large.

[0006] (4) The rotary kiln lime roasting process equipped with a vertical cooler and a preheater well solves the problem of uniformity of lime roasting, but the sealing is difficult, and only negative pressure production can be adopted. As a result, a large amount of cold air is drawn in, increasing the exhaust gas volume and oxygen content, reducing the thermal efficiency, and being not conducive to the recovery of CO2. In addition, the total heat dissipation area is large, making the energy consumption of the rotary kiln lime roasting process significantly higher than that of other lime roasting processes. The service life of its brick lining is also short, and the overall operating rate is low.

[0007] Regarding these foreign original patent lime roasting technologies mentioned above, due to the relatively high roasting temperature (1150°C - 1280°C), it promotes the formation of nitrogen oxides, increasing the environmental protection pressure and the costs and energy consumption of denitrification.

[0008] When the above lime roasting technology uses pulverized coal as fuel, the sulfur and ash in the coal pollute the lime, which not only increases the costs and energy consumption in the subsequent iron and steel production process but also causes a relatively large environmental protection pressure. It is necessary to add desulfurization and denitrification processes, which also increases the production costs and energy consumption. In the current state of technological development, the by-products of desulfurization and denitrification have not been well utilized, and there is actually serious secondary pollution. Generally speaking, the economic benefits of using pulverized coal to replace blast furnace or converter gas for power generation are far lower than the increase in the above iron and steel production costs, and its power generation efficiency is also much lower than that of large-scale regular coal-fired power plants. It is a wrong choice both economically and environmentally.

[0009] Even more seriously: If the above lime roasting technology uses low-calorie gases such as blast furnace gas, its output will be severely reduced. For example, for a 600-ton-per-day Maerz kiln, once it uses blast furnace gas, its daily output is very difficult to exceed 400 tons. Even if a relatively large amount of oxygen is added additionally, the increase in daily output is relatively limited, and it also increases a lot of production costs. Therefore, the above lime roasting technology or patent is not suitable for roasting lime with low-calorie gases.

[0010] The main content of the "Central Burner Lime Kiln" applied by Tangshan Jinquan Metallurgical Technology Industry Co., Ltd. on February 9, 2023, with the patent number CN116143425 A, is basically similar to the patents of the applicant, such as the "Energy-Saving and Environment-Friendly Active Lime Roasting Shaft Kiln" with the patent number ZL2003 2 0125614.X applied and approved on December 5, 2003, the "Energy-Saving and Environment-Friendly Active Lime Roasting Shaft Kiln" ZL2015 1 0361156.7 applied and approved on June x, 2015, and the "Large-Scale Air-Cooled Central Composite Burner for Roasting Shaft Kiln" CN204702668 U. However, it does not comprehensively understand the essence of the applicant's above-mentioned patent technology related to the central burner lime kiln. Due to serious problems in its furnace inner shape and combustion system, the performance of this patent promoted by Tangshan Jinquan Metallurgical Technology Industry Co., Ltd. in an enterprise in Benxi has not been normal since production started, and it has been forced to be transformed into other kiln types.

[0011] The Chinese patent with the publication number CN212894471U aims to provide a central burner for a single-shaft lime kiln with a stable bottom and good combustion quality. This central burner does not require the use of crossbeams and cooling devices. Firstly, its technical solution places the lower ends of the steel burner (2) and the burner refractory layer (4) on the support beam (1) inside the lime kiln, which is self-contradictory. Secondly, if the air-cooling device and its functions are cancelled, the problems of thermal expansion and contraction deformation of these components and the burning damage problem during abnormal furnace conditions will pose greater risks to production and equipment safety. The Chinese patent with the publication number CN218491636U also advocates not adopting cooling measures for the connecting beam, and there are the same above-mentioned risks.

[0012] The applicant's "Acid Oxidized Pellet Roasting Shaft Furnace" (ZL00260319.5, abbreviated as TCS shaft furnace), which was applied for and approved on November 17, 2000, built the combustion chamber in the center of the shaft furnace, and the entire roasting zone was annular, thus solving the problems of insufficient central air flow and uneven temperature distribution. However, the TCS shaft furnace cannot be directly applied to the roasting of reactive lime and needs to be improved to meet the requirements of roasting characteristics of materials such as carbonate roasting and the combustion characteristics of low-calorific-value gas. Based on the improvement of the TCS shaft furnace, the applicant's "Energy-saving and Environment-friendly Reactive Lime Roasting Shaft Kiln" (Patent No. ZL200320125614.X) applied for and approved on December 5, 2003, "Energy-saving and Environment-friendly Reactive Lime Roasting Shaft Kiln" (Patent No. ZL201510361156.7) applied for and approved on June 28, 2015, and "Large-scale Air-cooled Central Composite Burner for Roasting Shaft Kiln" (CN 204702668U) and other patents showed good production indicators when directly using low-calorific-value gas such as blast furnace gas. The product has been named the central burner TGS lime kiln by the China Lime Association, or simply referred to as the TGS lime kiln. In 2019, the Ministry of Ecology and Environment of China has listed the TGS lime kiln technology as an environmental protection "A" level enterprise matching process. According to the statistical data of the China Lime Association, the TGS lime kiln accounts for more than 35% of the domestic newly built and rebuilt gas-fired shaft kiln market, with stable and reliable production and good product quality. Entrusted by the China Lime Association, the applicant publishes the annual work report of the TGS central burner lime kiln on behalf of the China Lime Association at the annual meeting of the China Lime Association every year.

[0013] With the continuous increase in the scale of the TGS lime kiln, it has been found during continuous research and development and implementation that the technology still needs to be continuously improved and upgraded: when the particle size difference of the raw materials fed into the furnace is relatively large or the raw materials burst severely, it has a greater impact on production parameters and production indicators; with the increase in large-scale and cooling air volume, signs of uneven temperature distribution appear in the furnace, and the overburning and underburning rates of the products are threatened, etc. Summary of the Invention

[0014] To solve the above technical problems, the present invention provides a central burner lime kiln and an active lime roasting production process, which improve the strength of the sealing structure and the uniformity of the air flow, material flow, and temperature distribution, improve the production indexes, and can also be used in the drying process of granular materials or the roasting process of active magnesite and refractory materials.

[0015] To achieve this technical purpose, the present invention adopts the following scheme: The central burner lime kiln includes a furnace inner shape, a charging structure, a combustion system, a sealed discharging structure, and a furnace bottom sealing and bearing structure; the furnace inner shape is a blast furnace-like dumbbell-shaped furnace type, including a furnace throat, a furnace body, a furnace waist, and a furnace belly connected in sequence from top to bottom. Above the furnace throat, a furnace top bin and a charging structure are provided. The charging structure conducts two-stage charging at the furnace top bin and the furnace throat respectively to improve the charging effect of the lime kiln; below the furnace belly, a furnace bottom sealing and bearing structure is provided. The furnace bottom sealing and bearing structure supports the furnace inner shape and the sealed discharging structure. The sealed discharging structure includes a reciprocating push plate and a furnace bottom aggregate hopper. The discharge amount inside the kiln body is controlled by controlling the number of reciprocating movements of the reciprocating push plate, and the cumulative error of the height of each material discharge within the effective height range of the lime kiln is controlled to be stable within a set range; the combustion system includes a large-scale air-cooled composite central burner and side burners. The large-scale air-cooled composite central burner and the side burners form an inside-outside opposed firing, making the flame cover the entire cross-section of the furnace hearth and improving the temperature uniformity of the lime kiln.

[0016] Compared with the prior art, the beneficial effects of the present invention are as follows: The charging structure provided in this central burner lime kiln can conduct two-stage charging, improving the charging effect; the combustion system forms an inside-outside opposed firing through the central burner and the side burners, with strong central air flow, uniform and controllable temperature distribution, which is beneficial to the production of high-activity lime and significantly improves the production capacity; in cooperation with the furnace bottom sealing and bearing structure and the sealed discharging structure, it provides strong support for the large-scale development of lime kilns.

[0017] Furthermore, the bottom furnace sealing and load-bearing structure includes a bunker-shaped reinforced concrete foundation, a reinforced concrete ring beam, a first-level platform of the concrete foundation, a secondary pouring ring, and a sealing force transmission system. A reinforced concrete ring beam is poured on the bunker-shaped reinforced concrete foundation, and a sealing force transmission system is arranged on the reinforced concrete ring beam. The sealing force transmission system is divided into four parts. The first sealing force transmission system includes support columns, a bottom furnace sealing steel shell, connecting plates, and a furnace wall ring beam. Support columns are fixed on the upper surface of the reinforced concrete ring beam. The bottom furnace sealing steel shell is arranged outside the support columns. The connecting plates connect the bottom furnace sealing steel shell and the support columns into a truss-like integral ring-shaped structure, on which the furnace wall ring beam is connected and supported. Above the furnace wall ring beam, the inner shape of the furnace body is also connected and borne. The lower parts of the bottom furnace sealing steel shell and the support columns are fixed in the secondary pouring ring. The secondary pouring ring is located at the intersection of the inner side of the first-level platform of the concrete foundation and the upper surface of the reinforced concrete ring beam and is fixedly connected with and integrated with the two. The second sealing force transmission system includes a circular embedded iron and a bottom furnace air box. A circular embedded iron and a force transmission embedded iron are fixed on the inner side of the reinforced concrete ring beam. A bottom furnace aggregate hopper is connected above the force transmission embedded iron. The bottom furnace aggregate hopper is inserted into the bottom furnace air box. The bottom furnace air box is connected with a bottom furnace cooling air pipeline. The lower part of the bottom furnace aggregate hopper is connected to an intermediate bottom furnace discharge funnel. The lower opening of the bottom furnace aggregate hopper is connected to an upper hydraulic sealing discharge valve. The lower opening of the intermediate bottom furnace discharge funnel is connected to a lower hydraulic sealing discharge valve. The intermediate bottom furnace discharge funnel is also connected to a micro-dust collector and an external waste gas dust removal system, ensuring the smooth opening of the sealing discharge valve and environmental protection in the bottom furnace area during the discharging process under the furnace pressure above 50 KPa. The third sealing force transmission system includes a guiding device, a roller, and a reciprocating push plate. A guiding device and a roller are connected to the reinforced concrete ring beam. Both the guiding device and the roller are movably connected to the reciprocating push plate, playing a role in supporting and ensuring the reciprocating movement of the reciprocating push plate along a set track. A power device is connected to the outside of the reciprocating push plate, and the power device drives the reciprocating push plate to achieve reciprocating movement. The fourth sealing force transmission system includes a force transmission chassis, a load-bearing inclined strut, and a load-bearing beam. A force transmission chassis is fixed on the reinforced concrete ring beam. A load-bearing inclined strut is fixed on the force transmission chassis. A load-bearing beam is fixed on the load-bearing inclined strut. A large air-cooled composite central burner base is fixed at the center of the load-bearing beam.

[0018] Components in the bottom furnace sealing and load-bearing structure that may encounter temperatures above 200 °C, including the bottom furnace air box, load-bearing beam, large air-cooled composite central burner, and furnace wall ring beam, are all equipped with cooling air protection pipelines.

[0019] The bottom seal and load-bearing structure is located in the low-temperature area (lower part of the cooling zone) at the bottom of the furnace body. In particular, the bottom load-bearing beam transfers the received forces (mainly the gravity of the burden and the large air-cooled composite center burner, the impact force of charging or seismic force) to the upper surface of the reinforced concrete ring beam through load-bearing inclined braces; the furnace wall ring beam transfers the received forces (mainly the weight of the furnace wall refractory material, furnace shell, each platform, wind pressure, snow pressure, seismic force) to the upper surface of the reinforced concrete ring beam through support columns, the bottom seal steel shell of the furnace and corresponding reinforcing ribs and connecting plates, and completes the sealing and consolidation of force transmission through the secondary pouring ring, enabling the furnace body of this application to resist typhoons above level 17 or seismic intensity of degree 9, and at the same time making the sealing ability of the furnace body exceed 80 KPa.

[0020] Furthermore, the large air-cooled composite center burner includes a center burner conical cylinder and branch burners of the center burner. Above the center burner base, a center burner conical cylinder and a center burner cooling air partition are fixed. The center burner cooling air partition divides the center burner conical cylinder into an upward center burner cooling air chamber and a downward center burner cooling air chamber through the central axis. There is a gap between the center burner cooling air partition and the center burner top plate, so that the cooling air in the upward center burner cooling air chamber turns into the downward center burner cooling air chamber through this gap to complete the cooling protection of the entire center burner conical cylinder; refractory material is also cast outside the center burner conical cylinder to form a frustum-shaped refractory outer shape; the load-bearing beam includes a cross beam and a herringbone beam. Above the center burner conical cylinder, branch burners of the center burner are arranged. Each port of the branch burners of the center burner is connected with a center burner national well blade. Each branch burner of the center burner is independently connected with a gas pipeline and a combustion-supporting air pipeline. The gas pipeline and the combustion-supporting air pipeline are bent and laid on the upper side of the cross beam at the lower part of the center burner conical cylinder and pass through the bottom seal steel shell of the furnace wrapped by the herringbone beam; the branch burners of the center burner are divided into upper and lower rows of burners of the center burner. The elevation of the lower row of burners of the center burner = the elevation of the first row of side burners ± 200 mm, and the elevation of the upper row of burners of the center burner = the elevation of the fourth row of side burners ± 200 mm. The small TGS lime kiln allows only one row of branch burners to be set for the center burner.

[0021] The height of the large-scale air-cooled composite central burner is such that its overall shape is a cone with a thinner upper part and a thicker lower part to improve its force stability. The large-scale air-cooled composite central burner is located above the cruciform beam on the bottom of the middle and lower part of the furnace body, while its combustion air pipe, gas pipe and protective air beam are located below the lower part of the cooling zone or even below the furnace bottom, avoiding the high-temperature zone and extending the service life. The protective air of the central burner is cooling air, which enters from one side and exits from the other side, then is sent to the furnace wall ring beam, support columns and load-bearing diagonal braces, and then is released into the free space at the bottom of the furnace below the reciprocating push plate and its frame at the bottom of the furnace, continuing to cool and protect them, while recovering heat and improving the energy utilization rate; the protective air beam adopts a herringbone beam and its width is reduced to reduce its adverse impact on the uniformity of material feeding. At the same time, the combustion air and gas pipes of each burner of the large-scale air-cooled composite central burner are led outside the furnace for adjustment and control.

[0022] Furthermore, side burners are installed on the side wall of the furnace wall. The side burners include combined Guojing side burners and / or independent Guojing side burners, and / or temperature-regulating air outlets and temperature-regulating air spray guns; the combined Guojing side burners are arranged in the middle and lower part of the furnace wall, and independent Guojing side burners and temperature-regulating air spray guns are arranged row by row on it, while the temperature-regulating air outlet is arranged below the combined Guojing side burners.

[0023] Furthermore, the combined Guojing side burner belongs to a stacked structure from bottom to top. Each row of side burners of the combined Guojing side burner is connected with an air channel and a gas channel, and combined side burner Guojing blades are arranged at the ejection ports of the air channel and the gas channel; and / or the independent Guojing side burner includes: an independent side burner combustion air channel, an independent side burner gas channel and independent side burner Guojing blades; the independent side burner gas channel is located in the center of the independent Guojing side burner, and independent side burner Guojing blades are fixed both inside and outside near the ejection port of the independent side burner gas channel, and it is indented 15 - 30 mm compared with the outer sleeve pipe; an annular channel is formed between the independent side burner gas channel and the outer sleeve pipe of the independent Guojing side burner, and the annular channel is the independent side burner combustion air channel.

[0024] The combined Guojing side burner greatly compresses the height between the burners, enabling the combustion flame to quickly cover the entire cross-section of the combustion zone, improving the utilization rate of the roasting zone volume. The 4th, 5th, 6th, and 7th row burners adopt independent Guojing burners and temperature-regulating air, thus making the distribution of the combustion heat of the side burners and the combustion heat of the large-scale air-cooled composite central burner more uniform in the radial direction of the furnace body, and improving the lime activity of the TGS lime kiln.

[0025] Furthermore, the furnace throat and the upper part of the furnace body form an upper dumbbell head structure with thin upper and lower ends and thick middle part; the middle part of the furnace body is the refractory inner shape of the straight cylinder section of the furnace body or a tapered inner shape with a thin upper part and a thick lower part close to a straight cylinder, constituting the middle part of the dumbbell-shaped structure; the lower part of the furnace body is a lower expansion type structure with gradually decreasing furnace body angles, and the lower part of the furnace body, the furnace waist and the furnace belly together form a lower dumbbell head structure with thin upper and lower ends and thick middle part.

[0026] The ten-section dumbbell-shaped furnace inner shape structure proposed by the present invention is suitable for the characteristics of low thermal conductivity of the newly formed lime layer and slow combustion of low calorific value gas, prolongs the preheating time of the raw materials just entering the furnace and the cooling time of the finished products, reduces the furnace body height in the preheating zone and the cooling zone, saves the gas pressure difference in these two places, improves the product quality, and saves energy and reduces emissions.

[0027] Furthermore, the furnace throat includes a furnace throat top plate, a refractory inner shape of the furnace throat straight cylinder section, and a refractory inner shape of the furnace throat contraction section connected in sequence from top to bottom, and the angle of the refractory inner shape of the furnace throat contraction section is 45° - 86°; and / or the furnace body includes a refractory inner shape of the upper straight cylinder section of the furnace body, a refractory inner shape of the furnace body expansion section, a refractory inner shape of the middle straight cylinder section of the furnace body, a refractory inner shape of the furnace body contraction section, and a refractory inner shape of the lower section of the furnace body connected in sequence from top to bottom. The furnace body expansion angle of the refractory inner shape of the furnace body expansion section is 70° - 88°; the refractory inner shape of the middle straight cylinder section of the furnace body or a tapered inner shape with a thin upper part and a thick lower part close to a straight cylinder, and the furnace body angle of the tapered inner shape is greater than 86°, which is the main part of the furnace body; the furnace body angle of the refractory inner shape of the furnace body contraction section is 70° - 86°, and the furnace body angle of the refractory inner shape of the lower section of the furnace body is 55° - 82°, so that the furnace body as a whole forms a gradually outward expanding trumpet-shaped structure; and / or the refractory inner shape of the furnace waist is a straight cylinder shape or a round belly shape, and its diameter is larger than the diameters of other parts of the furnace body; and / or the furnace belly includes a first furnace belly refractory inner shape with a furnace belly angle of 71° - 88° and a second steel cooling belt hopper furnace belly inner shape with a furnace belly angle of 75° - 88°; and / or the ratio of the effective height of the furnace inner shape to the diameter at the lower edge of the refractory inner shape of the middle straight cylinder section of the furnace body is 5.5 - 6.2, which has great value for improving production, quality and energy utilization rate.

[0028] Furthermore, the feeding structure includes a furnace top receiving hopper, a variable-speed spiral feeder, a furnace top bin and a multi-tube feeder; the furnace top receiving hopper, the variable-speed spiral feeder, the furnace top bin and the multi-tube feeder are arranged in series from top to bottom on the central axis of the furnace top. The furnace top receiving hopper is fixed above the variable-speed spiral feeder, and the lower part of the variable-speed spiral feeder is the main bin of the furnace top bin. The variable-speed spiral feeder conducts the first feeding into the furnace top bin; an air-cooled bottom plate is installed at the bottom of the furnace top bin, and a multi-tube feeder is hung on the air-cooled bottom plate. The multi-tube feeder connects the furnace top bin with the furnace throat, and the multi-tube feeder conducts the second feeding to the furnace throat material surface. The multi-tube feeder is an assembly of two or more feeding throat pipes, and the feeding throat pipes are hung on the air-cooled bottom plate of the furnace top bin. The length of the feeding throat pipes gradually shortens from the center of the furnace throat to the edge according to the material line stacking angle.

[0029] The variable-speed spiral distributor achieves spiral multi-ring distribution, making the material distribution in the kiln more uniform. With a rather simple structure, it replaces the function of adjusting the inclination angle of the blast furnace chute, meets the material distribution requirements of large-diameter kilns, and at the same time increases the bearing capacity and service life of the air-cooled bottom plate of the top bin. In cooperation with the large-throat multi-tube distributor, using the funnel effect of each feeding tube, the fine-grained raw materials are concentrated at the pile tip. The area here is small, the air permeability is poor, and its position in the furnace is fixed. The coarse-grained raw materials are concentrated at the pile corners and other positions. The area here is large, the air permeability is good, and its position in the furnace is also fixed, which is convenient for arranging burners corresponding to the pile tip, strengthening the heat supply capacity at the pile tip, improving the uniformity of the gas flow and temperature in the furnace, saving the pressure difference, and increasing the output. When the lime kiln discharges materials at the bottom, the raw materials in the top bin of the furnace are immediately automatically replenished into the furnace. Therefore, as long as there is no shortage of materials in the top bin of the furnace in this patent and the material surface height in the top bin of the furnace fluctuates within the set range, it can ensure that the top material surface in the furnace is always constant. This state has great value for stabilizing the roasting gas flow in the furnace. At the same time, the area corresponding to the height of the large-throat multi-tube distributor is a stable free space and is in a slightly negative pressure state. In cooperation with the material sealing function of the large-throat multi-tube distributor and multiple evenly distributed top exhaust gas outlets, a small amount of cold air enters the furnace along the gaps between the raw materials in the feeding tube, which not only improves the environmental protection at the top of the furnace, reduces the temperature of the large-throat multi-tube distributor, but also is conducive to the stable overflow of the roasting gas flow in the furnace.

[0030] Another object of the present invention is to provide a production process for roasting active lime using low calorific value gas, which is carried out in the above-mentioned central burner lime kiln and includes the following steps: S1. Qualified raw materials are subjected to primary distribution by a variable-speed spiral distributor, forming an effect of disk-shaped multi-ring distribution similar to mosquito coils in the top bin of the furnace. When the central burner lime kiln discharges materials outward, the raw materials in the top bin of the furnace are automatically replenished into the furnace by gravity through the multi-tube distributor for secondary distribution of the furnace charge. S2. The raw materials entering the furnace start the feeding movement. Under the conditions of complete countercurrent heating and reaction and uniform hot gas flow heating, they complete drying, preheating, roasting, decomposition, and cooling, and then fall onto the reciprocating push plate. Through the reciprocating movement of the reciprocating push plate, the cooled furnace charge is quantitatively and evenly discharged into the bottom aggregate hopper of the furnace and discharged out of the furnace through the sealed discharge valve.

[0031] Compared with the prior art, the process method of the present invention has the following beneficial effects: Using the above production process, when all blast furnace gas is used, the production effect of the central burner TGS850 lime kiln is greatly improved: the daily output per furnace is 840 - 939 t / d, and the utilization coefficient of the effective volume above the cooling zone of the TGS lime kiln during full-load production reaches 1.3 t / d.m 3As above. The raw material CaO is 47.2 - 49.6%. When using all blast furnace gas, the heat consumption is 862 - 941×4.1868 KJ / kg ash; when the raw material CaO is 53.2 - 54.95%, the heat consumption using all blast furnace gas is 901 - 1087×4.1868 KJ / kg ash. The corresponding product CaO is 89.19 - 94.40% and the activity is 329 - 402 ml.

[0032] Furthermore, after the cooling air completes the cooling protection of the hearth air box, the bearing beam, the large air-cooled composite central burner, and the furnace wall ring beam, it enters the cooling zone charge column through the gap between the cooling zone hopper, the bearing beam, and the lower edge of the central burner base and the reciprocating push plate, and then passes upward through the gaps between the lumps to cool the lumps; when all the cooling air ascends to the lower section of the furnace body, its temperature has risen above 400 °C. Here, a part of the hot cooling air is led out as the temperature regulating air through the temperature regulating air outlet, sent upward to the temperature regulating air spray gun, and then sprayed into the furnace to participate in combustion; the remaining part of the hot cooling air continues to ascend in the charge column, enters the roasting zone and also participates in combustion, reducing the excess air coefficient of the combustion air in the whole furnace and improving the energy utilization rate; the combustion-supporting air and the low-calorie gas are preheated to 180 - 260 °C outside the furnace and then sent to the combustion system, and are sprayed into the gaps of the charge column in the furnace through the side burners and the central burner for mixing and combustion, and form an inside-out opposed combustion to increase the penetration ability of the flame; the roasting flame and the waste gas move upward along the gaps of the charge column in the furnace, complete the roasting, preheating, and drying of the charge while burning, overflow from the top surface of the charge, enter the free space at the top of the furnace, and then are discharged outside the furnace through the waste gas outlet at the top of the furnace. The temperature in the main area of the roasting zone is controlled at 1050 - 1120 °C, and the tiny area of the highest temperature will not exceed 1250 °C in a short time, and the oxygen partial pressure at this place is lower than 0.15 KPa, forming a uniformly distributed flame waste gas with a more uniform temperature distribution; it also eliminates the thermodynamic conditions for the generation of NOx, and the low-calorie gas originally contains much less sulfur than coal, reducing the total amount of pollutants generated from the source. Without equipping desulfurization and denitrification equipment, it can meet the ultra-low emission standards. Brief Description of the Drawings

[0033] Figure 1 It is the cross-sectional structure general drawing of the central burner lime kiln provided by the present invention; Figure 2 It is the schematic diagram of the furnace body bearing and sealing structure and the upper and lower hydraulic sealing discharge valves provided by the present invention; Figure 3 It is the top view partial enlarged schematic diagram of the installation of the support structure of the furnace bottom discharge system. Since this top view is a structure that is symmetric about the center cross, a 1 / 4 unit view is selected; Figure 4 It is the top view partial enlarged drawing of the installation of the furnace bottom bearing structure. Since this top view is a structure that is symmetric about the center cross, a 1 / 4 unit view is selected; Figure 5 Enlarged installation schematic diagram of the bottom push plate discharging device provided by the present invention; Figure 6 Enlarged installation schematic diagram of the bearing inclined strut provided by the present invention; Figure 7 Top view installation schematic diagram of the bottom push plate discharging system and the power device provided by the present invention. Since this top view is a structure symmetric about the center cross, a 1 / 4 unit view is used; Figure 8 Top view partial installation schematic diagram of the upper surface structure of the reciprocating push plate provided by the present invention. Since this top view is a structure symmetric about the center cross, a 1 / 4 unit view is selected; Figure 9 Structural cross-sectional view of Embodiment 1 of the guiding and supporting mechanism provided by the present invention; Figure 10 For Figure 9 Sectional view D-D in Figure 11 Structural schematic diagram of the idler roller in Embodiment 1 of the guiding and supporting mechanism provided by the present invention; Figure 12 For Figure 11 Partial longitudinal sectional structure schematic diagram in the E direction in Figure 13 Schematic diagram of the rack contact plate in Embodiment 1 of the guiding and supporting mechanism provided by the present invention; Figure 14 Structural cross-sectional view of Embodiment 2 of the guiding and supporting mechanism provided by the present invention; Figure 15 For Figure 14 Sectional view F-F in Figure 16 Structural schematic diagram of the inner shape of the furnace body of the central burner lime kiln provided by the present invention; Figure 17 For Figure 1 Partially enlarged view of the C-C section in . Since the C-C sectional view is a structure symmetric about the center cross, a 1 / 4 unit view is selected; Figure 18 Installation schematic diagram of each burner of the central burner lime kiln provided by the present invention; Figure 19 Enlarged installation schematic diagram of the central burner of the TGS lime kiln provided by the present invention; Figure 20 Schematic diagram of the cone framework of the central burner of the TGS lime kiln provided by the present invention; Figure 21 Top view schematic diagram of the central burner of the TGS lime kiln; Figure 22 Installation schematic diagram of the combined national well side burner of the TGS lime kiln; Figure 23 For Figure 22 the view in the M direction; Figure 24 Schematic diagram of the installation of the independent shaft side burners of the TGS lime kiln; Figure 25 For Figure 24 the view in the N direction; Figure 26 For Figure 1 the 1 / 4 unit view of the A-A cross-section. Since the A-A cross-section view is a structure symmetric about the center cross, the 1 / 4 unit view is selected; Figure 27 Schematic diagram of the variable-speed spiral distributor and the multi-ring multi-tube distributor provided by the embodiment of the present invention; Figure 28 For Figure 27 the 1 / 4 unit view of the B-B cross-section. Since the B-B cross-section view is a structure symmetric about the center cross, the 1 / 4 unit view is selected; Figure 29 Enlarged schematic diagram of the variable-speed spiral distributor provided by the embodiment of the present invention; The markings in the figure are: 1. Top charging hopper; 2. Top support frame; 3. Variable-speed spiral distributor; 301. Central throat pipe; 302. Frequency conversion motor; 303. Variable-speed and rotary support system device; 304. Sealing strip; 305. Distributing chute; 306. Trunnion; 307. Connecting chain; 308. Sieve bar; 4. Top bunker; 5. Bunker skeleton; 6. Air-cooled bottom plate; 7. Top protection air inlet; 8. Top protection air outlet; 9. Throat roof plate; 10. Throat steel shell; 11. Top waste gas outlet; 12. Multi-tube distributor; 1201. Distributing throat pipe; 13. Top stock surface; 14. Lightweight thermal insulation material layer; 15. Heavy-duty refractory working layer; 16. Inner shape of refractory in the straight section of the throat; 17. Steel shell of the throat contraction section; 18. Inner shape of refractory in the throat contraction section; 19. Inner shape of refractory in the upper straight section of the furnace body; 20. Inner shape of refractory in the furnace body expansion section; 21. Steel shell of the straight section of the upper furnace body; 22. Inner shape of refractory in the middle straight section of the furnace body; 23. Inner shape of refractory in the furnace body contraction section; 24. Inner shape of refractory in the lower furnace body; 25. Side burners in the fifth to seventh rows; 26. Temperature-regulating air spray gun; 27. Side burners in the fourth row; 2701. Independent side burner connecting three flanges; 2702. Combustion-supporting air passage of the independent side burner; 2703. Independent side burner connecting two flanges; 2704. Gas passage of the independent side burner; 2705. Guojing blade of the independent side burner; 28. Combined Guojing side burner; 2801. First row air passage of the combined side burner; 2802. First row gas passage of the combined side burner; 2803. Second row air passage of the combined side burner; 2804. Second row gas passage of the combined side burner; 2805. Third row air passage of the combined side burner; 2806. Third row gas passage of the combined side burner; 2807. Peephole; 2808. Guojing blade of the combined side burner; 2809. Outer sleeve of the combined side burner; 29. Temperature-regulating air outlet; 30. Steel shell of the lower furnace body; 31. Large air-cooled composite central burner; 3101. Central burner roof plate; 3102. Lower row burners of the central burner; 3103. Upper row burners of the central burner; 3104. Vertical rib plate of the central burner; 3105. Annular rib plate of the central burner; 3106. Cooling air partition plate of the central burner; 3107. Upper chamber of the cooling air of the central burner; 3108. Lower chamber of the cooling air of the central burner; 3109. Outer shape of the refractory of the central burner; 3110. Conical cylinder of the central burner; 3111. Guojing blade of the central burner; 32. Inner shape of refractory in the furnace waist; 33. Inner shape of refractory in the furnace belly; 34. Steel shell of the furnace waist; 35. Central burner base; 36. Furnace wall ring beam; 37. Cooling zone hopper; 38. Cross beam; 39. Load-bearing diagonal brace; 40. Force-transferring chassis; 41. Discharge stock surface; 42. Bonding block crushing teeth; 43. Sector reciprocating push plate and its frame; 4301. Guide square steel; 44. Guide device; 4401. Fixed slide rail wheel; 4402. Bearing; 45. Guide rail; 4501. Angle steel; 46. Guide device bracket; 47. Support roller; 4701. Rack contact plate; 4702. Roller; 4703. Limit tooth;4704, anti-loosening backing plate; 4705, nut; 4706, bolt; 4707, bushing; 4708, steel plate; 48, idler support; 49, power device; 50, power support structure; 51, force-transferring embedded iron; 52, auxiliary diagonal brace; 53, first-floor platform of concrete foundation; 54, secondary casting ring; 55, furnace-bottom grid beam; 56, support column; 57, furnace-bottom sealed steel shell; 58, sealing ring plate; 59, reinforcing rib; 5901, support plate; 60, connecting plate; 61, furnace-bottom air box; 62, annular embedded iron; 63, reinforced concrete ring beam; 64, furnace-bottom aggregate hopper; 65, furnace-bottom cooling air valve; 66, furnace-bottom cooling air pipeline; 67, bunker-shaped reinforced concrete foundation; 68, lower hydraulic-sealed discharge valve; 69, discharge port; 70, foundation pier; 71, intermediate discharge hopper; 72, upper hydraulic-sealed discharge valve; 73, pressure-relief pipeline; 74, pressure-relief valve; 75, mini dust collector; 76, power mechanism of upper hydraulic-sealed discharge valve; 77, main cooling air inlet valve and pipeline; 78, lower gas valve and pipeline of central burner; 79, upper gas valve and pipeline of central burner; 80, lower air valve and pipeline of central burner; 81, upper air valve and pipeline of central burner; 82, herringbone beam; Specific embodiments

[0034] To fully understand the purpose, features and effects of the present invention, the present invention will be described in detail through the following specific embodiments, but the present invention is not limited thereto.

[0035] Please refer to Figure 1 , a central burner lime kiln provided by the present invention includes an inner furnace shape, a feeding structure, a furnace-bottom sealed load-bearing structure, a sealed discharge structure and a combustion system; the inner furnace shape is a blast-furnace-like dumbbell-shaped furnace shape, and the inner furnace shape includes a furnace throat, a furnace body, a furnace waist and a furnace belly connected in sequence from top to bottom. A furnace-top bin 4 and a feeding structure are provided above the furnace throat. The feeding structure conducts two feedings at the furnace-top bin 4 and the furnace throat respectively to improve the feeding effect; a furnace-bottom sealed load-bearing structure is provided below the furnace belly. The furnace-bottom sealed load-bearing structure supports the inner furnace shape of the kiln and the sealed discharge structure. The sealed discharge structure includes a reciprocating push plate and a furnace-bottom aggregate hopper 64. The discharge amount inside the kiln body is controlled by controlling the number of reciprocating movements of the reciprocating push plate, and the cumulative error of the height of each material discharge within the effective height range of the lime kiln is stabilized within a set range; the combustion system includes a large-scale air-cooled composite central burner and side burners. The large-scale air-cooled composite central burner and the side burners form an inside-out opposite firing, so that the flame covers the entire cross-section of the furnace chamber, improving the temperature uniformity of the lime kiln.

[0036] On the basis of this solution, the bottom sealing and load-bearing structure of the furnace is divided into four major sealing and force-transferring systems, namely the first sealing and force-transferring system, the second sealing and force-transferring system, the third sealing and force-transferring system, and the fourth sealing and force-transferring system. Each sealing and force-transferring system cooperates with each other to disperse and jointly bear the forces or shaking energies generated by typhoons, earthquakes, the sitting of furnace charge, the self-weight of furnace charge, the expansion force of furnace charge, refractories, steel structures, the self-weights of various equipment of the furnace body, etc.

[0037] Such as Figure 2 , the block-shaped reinforced concrete foundation 67 is located at the bottommost part of the lime kiln furnace body, buried underground by a certain dimension, and supported on the pier 70 of the pile foundation. A reinforced concrete ring beam 63 is continuously cast on its upper part, and all the forces of the entire furnace converge here.

[0038] The first sealing and force-transferring system includes a reinforced concrete ring beam 63, a support column 56, a bottom-sealing steel shell 57 of the furnace, a connecting plate 60, and a furnace wall ring beam 36. On the upper surface of the reinforced concrete ring beam 63, there is a force-transferring embedded iron 51. The support column 56 is fixed on the force-transferring embedded iron 51. The bottom-sealing steel shell 57 of the furnace is arranged outside the support column 56. The lower edge of the bottom-sealing steel shell 57 of the furnace is fixed with a sealing ring plate 58. Several connecting plates 60 connect the bottom-sealing steel shell 57 and the support column 56 into an integral ring-shaped column-like good-force-bearing structure similar to a ring truss at a certain distance. The furnace wall ring beam 36 is connected and supported thereon. The furnace wall ring beam 36 is fixed with a reinforcing rib 59. Above the furnace wall ring beam 36, there are also connected and borne with furnace wall refractories, a furnace waist steel shell 34, a lower-section steel shell 30 of the furnace body, a straight-section steel shell 21 of the furnace body, a throat contraction-section steel shell 17, a throat steel shell 10, a top cloth-feeding structure of the furnace, a platform ladder, corresponding pipelines and equipment, etc. The furnace wall refractories include a lightweight thermal insulation material layer 14 and a heavy-duty refractory working layer 15. A cooling zone hopper 37 is hung inside the furnace wall ring beam 36. The lower parts (welded with anchor bolts) of the bottom-sealing steel shell 57 of the furnace and the support column 56 are fixed in the secondary pouring ring 54.

[0039] Straighten and weld the tie bars inside the steel bar mesh of the first-layer platform 53 of the concrete foundation poured at one time to become the tie bars of the secondary pouring ring 54, and roughen the inner side surface of the first-layer platform 53 of the concrete foundation. The vertical bars of the steel bar mesh of the secondary pouring ring 54 are fixed in the reinforced concrete ring beam 63 poured at one time. Thus, the secondary pouring ring 54 completely forms a relatively thick integral ring-shaped structure, and is completely integrated with the upper surface (roughened) of the reinforced concrete ring beam 63 poured at one time and the concrete inside the first-layer platform 53 of the concrete foundation, greatly improving the structural strength and sealing ability.

[0040] The second sealing and force-transmitting system includes an annular pre-embedded iron 62, a sealing ring plate 58, a furnace bottom hopper 64, and a furnace bottom wind box 61. The cylindrical annular pre-embedded iron 62 and the force-transmitting pre-embedded iron 51 are pre-embedded inside the reinforced concrete ring beam 63. The sealing ring plate 58 is continuously welded to the upper side of the force-transmitting pre-embedded iron 51, and the furnace bottom hopper 64 is suspended from the lower side of the sealing ring plate 58. The furnace bottom wind box 61 includes an air-spraying plate and a conical plate. The air-spraying plate of the furnace bottom wind box 61 is welded to the inner side of the sealing ring plate 58. The conical plate of the furnace bottom wind box 61 is welded between the lower part of the annular pre-embedded iron 62 and the furnace bottom hopper 64. Ventilation holes are evenly distributed along the upper edge of the furnace bottom hopper 64, and the shape of the vents is preferably semicircular. The conical plate of the furnace bottom wind box 61 is connected to a furnace bottom cooling air duct 66, which is equipped with a furnace bottom cooling air valve 65. This cooling air is supplied to the furnace bottom wind box 61 through the furnace bottom cooling air duct 66. This cooling air enters the gap between the air blower plate of the furnace bottom wind box 61 and the furnace bottom collecting hopper 64 through multiple semicircular air blowholes evenly distributed at the top of the furnace bottom collecting hopper 64. It is then sprayed into the lime discharged into the furnace bottom collecting hopper 64, providing final cooling for the product. The room-temperature cooling air in the furnace bottom wind box 61 simultaneously cools the reinforced concrete ring beam 63 and surrounding components, preventing the high-temperature product from threatening the non-heat-resistant reinforced concrete ring beam 63 under special furnace conditions and keeping it below 200°C.

[0041] The sealed discharge structure also includes an upper hydraulic sealed discharge valve 72 and a lower hydraulic sealed discharge valve 68. The upper hydraulic sealed discharge valve 72 with a flange connection is installed on the lower edge of the furnace bottom collecting hopper 64. A hydraulic clock valve is preferably used. The fixed pulley of the zipper used for the upper hydraulic sealed discharge valve 72 is installed on the furnace bottom well beam 55. The upper hydraulic sealed discharge valve power mechanism 76 is sealed and installed in the middle of the furnace bottom sealing steel shell 57. The working principle of the upper hydraulic sealed discharge valve 72 is similar to that of the blast furnace gas shut-off valve. An elastic top plate is provided on the intermediate hopper 71 for discharging materials from the furnace bottom. The elastic top plate is fixed to the lower part of the collecting hopper 64 at the furnace bottom. A lower hydraulic sealed discharge valve 68 is installed at the lower opening of the intermediate hopper 71 for discharging materials from the furnace bottom. The lower opening of the lower hydraulic sealed discharge valve 68 is the discharge port 69. A micro dust collector 75 is installed on the elastic top plate of the intermediate hopper 71 for discharging materials from the furnace bottom. The micro dust collector 75 is connected to the pressure relief pipe 73 and pressure relief valve 74 of the micro dust collector 75, and is also connected to the external environmental exhaust pipe. The micro dust collector 75 is a dust collector that uses fine metal wire braid as the filter medium. After the upper hydraulic sealed discharge valve 72 is closed and before the lower hydraulic sealed discharge valve 68 is opened, the high-pressure dust-laden air is pumped into the external environmental dust removal system. Under a furnace pressure of more than 50 kPa, the smooth opening of the sealed discharge valve and the environmental protection of the furnace bottom area during the discharge process are ensured.

[0042] like Figures 2 to 5As shown, the third sealed force transmission system primarily supports the sealed discharge structure. This structure comprises a reciprocating push plate, a furnace bottom collecting hopper 64, a sealed discharge valve, and a furnace bottom discharge intermediate funnel 71. A power unit 49 is connected to the outer side of the reciprocating push plate. The power unit 49 passes through the furnace bottom sealed steel shell 57 and forms a sealed connection therewith. The power unit 49 drives the reciprocating push plate to achieve reciprocating motion and discharge. The power unit 49 is connected to a power support structure 50, which is supported by pre-embedded force transmission iron on the upper surface of the concrete foundation platform 53 to prevent fatigue damage to the furnace bottom sealed steel shell 57. A guide support mechanism is connected below the reciprocating push plate to ensure that the reciprocating push plate moves along a set trajectory.

[0043] like Figures 1 to 5 、 Figures 7 to 8 In some preferred embodiments, the reciprocating push plate is fan-shaped and has a frame disposed beneath it. The overall structure is collectively referred to as the fan-shaped reciprocating push plate and its frame 43. A guide support mechanism is connected below the fan-shaped reciprocating push plate and its frame 43. The guide support mechanism includes rollers 47 and roller brackets 48, a guide device 44, and a guide bracket 46. A force-transmitting embedded iron 51 is fixed to the upper surface of the reinforced concrete ring beam 63. The guide bracket 46 and roller bracket 48 are welded to the force-transmitting embedded iron 51. The upper portion of each bracket is connected to each other by a crossbeam to form a polygonal load-bearing structure and is protected by cooling air. Rolling rollers 47 are provided on the upper surface of the roller bracket 48, which roll and support the fan-shaped reciprocating push plate and its frame 43 above. The inner side of the guide bracket 46 is connected to and supports the furnace bottom cross-beam 55 through reinforcing ribs 59 and the support plate 5901.

[0044] A guide rail 45 is provided on the upper surface of the guide device bracket 46, and a guide device 44 is installed in the guide rail 45. The guide device 44 not only provides auxiliary rolling support for the fan-shaped reciprocating push plate and its frame 43, but also can keep the fan-shaped reciprocating push plate and its frame 43 to perform reciprocating motion along a set trajectory (preferably a straight line) to complete discharge, thereby preventing deviation and damaging the power device 49; the preferred number of this system is four to sixteen sets.

[0045] In some preferred embodiments, the upper surface of the sector-shaped reciprocating push plate and its frame 43 is fixed with slug-breaking teeth 42 to break up lumps within the furnace. The discharge surface 41 represents the discharge outlet. If lumps occur under unusual furnace conditions, the slug-breaking teeth 42, along with the reciprocating motion of the push plate, rub and break up the lumps, ensuring uniform and stable discharge.

[0046] During discharge, the power unit 49 drives the fan-shaped reciprocating push plate and its frame 43 in reciprocating motion. The cooled finished charge is discharged quantitatively along the discharge surface 41 of the discharge opening between the lower edge of the cooling belt hopper 37 and the fan-shaped reciprocating push plate and its frame 43 into the furnace bottom collection hopper 64 below. The discharge volume per reciprocating motion is proportional to the height of the discharge opening multiplied by the lateral area of the arc length and the reciprocating distance of the fan-shaped reciprocating push plate and its frame 43. The discharge weight inside the kiln is controlled by varying the number of reciprocating motions during each discharge. This invention achieves unprecedented discharge uniformity within the furnace: the cumulative discharge height error is within ±1.5% over the entire effective discharge distance range of 25 to 32.5 meters.

[0047] Regarding the implementation structure of the load-bearing function and guiding function of the fan-shaped reciprocating push plate and its frame 43 during the reciprocating motion, especially to deal with the randomness and unevenness of the impact force of the material sitting, that is, the force on the upper surface of the fan-shaped reciprocating push plate and its frame 43 has an uncertain eccentric tendency, so that the impact force of the local discharge structure or the local area on the same discharge plate reaches several times the impact force of other parts of the material sitting, etc., it is mainly achieved through the roller 47 and the guide device 44, and then assisted by the safety height (15 to 20 mm) set between the lower edge of the cross beam and the fan-shaped reciprocating push plate and its frame 43 to prevent the fan-shaped reciprocating push plate and its frame 43 from tipping over. There are many specific implementation structures, and some of the implementation structures are listed below: Implementation structure 1: Reference Figure 5 、 Figures 9 to 13 Roller 47 comprises a rack contact plate 4701, roller 4702, limiting teeth 4703, anti-loosening pad 4704, nut 4705, bolt 4706, sleeve 4707, and steel plate 4708. Roller 4702 is cylindrical, with limiting teeth 4703 on both sides. Limiting teeth 4703 function as single-tooth gears, and are secured together by two sets of bolts 4706, sleeve 4707, nut 4705, and anti-loosening pad 4704. Rack contact plates 4701 are provided above and below roller 47, and are respectively secured to roller bracket 48 and beneath steel plate 4708 of the fan-shaped reciprocating push plate and its frame 43. This "single-tooth gear-rack" structure prevents roller 47 from deviating. The guide device 44 is a spherical body, and guide rails 45 are provided on both sides of the guide device 44. The guide rails 45 on both sides are fixedly mounted on the guide device bracket 46. The guide rail 45 is an angle steel 4501 with a built-in arc plate. The radius of the arc plate is slightly larger than the radius of the spherical body. A guide square steel 4301 is provided in the middle of the two spherical bodies. The guide square steel 4301 is fixedly mounted under the fan-shaped reciprocating push plate and its frame 43, and moves with the movement of the fan-shaped reciprocating push plate and its frame 43, forming a linear reciprocating motion state similar to a ball bearing. This structure is suitable for large kilns with large and uneven forces.

[0048] Implementation Structure 2: Refer to Figure 14 and Figure 15 , more than three fixed slide pulleys 4401 with relatively high flanges on both sides are fixedly installed on the idler bracket 48 and / or the guide device bracket 46. To improve their slow-speed bearing capacity, especially the axial bearing capacity, their bearings 4402 are preferably graphite lubricated shoulder sliding friction bearings, and the corresponding guide square steel 4301 is installed under the sector reciprocating push plate and its frame 43 and moves with the movement of the sector reciprocating push plate and its frame 43. The fixed slide pulley 4401 has a strong bearing capacity and can replace the idler 47 in Implementation Structure 1, and is suitable for small-scale kilns. Conversely, it can also be designed as a "moving slide pulley", similar to the reciprocating movement of a trolley. It should be particularly noted that the material impact force received by the sector reciprocating push plate and its frame 43 is very large, and it has a great relationship with the scale and structure of the furnace. The shafts and support bearings of the slide pulleys need to be strengthened in strength.

[0049] Implementation Structure 3: Regarding the realization of the bearing and guiding functions of the sector reciprocating push plate and its frame 43, high-strength precision-machined square steel, square tubes or round steel are designed and fixedly installed at the lower or middle part of the sector reciprocating push plate and its frame 43 and move with the movement of the sector reciprocating push plate and its frame 43. Fixed wear-resistant square tube sleeves or round tube sleeves with low friction coefficients are designed at both ends for bearing, positioning and guiding.

[0050] Implementation Structure 4: Regarding the realization of the bearing and guiding functions of the sector reciprocating push plate and its frame 43, another option is to design high-strength precision-machined "channel steel" or semi-circular tubes and fixedly install them under the sector reciprocating push plate and its frame 43 and move with the movement of the sector reciprocating push plate and its frame 43, while high-strength precision-machined square steel, square tubes or round steel are fixedly installed on the idler bracket 48 and the guide device bracket 46, so that the "channel steel" or semi-circular tubes buckle the square steel, square tubes or round steel, similar to the reciprocating movement of a slider, for bearing, positioning and guiding.

[0051] Other stop wheel devices, connecting rod devices, lever devices, chain devices, weight devices, etc. are designed according to the above principles and requirements, and can also realize the bearing function and guiding function of the reciprocating movement of the sector reciprocating push plate and its frame 43, which will not be elaborated one by one.

[0052] Such as Figures 2 to 4 and Figure 6As shown in the figure, the fourth sealing and force transmission system includes a force transmission chassis 40, a load-bearing diagonal brace 39, an auxiliary diagonal brace 52, a cross beam 38, and a central burner base 35, which mainly support the large-scale air-cooled composite central burner 31. A force transmission embedded iron 51 is fixed on the upper surface of the reinforced concrete ring beam 63. The force transmission chassis 40 is welded to the force transmission embedded iron, and the load-bearing diagonal brace 39 protected by cooling air is welded to the force transmission chassis 40 and reinforced by a reinforcing rib 59. The larger load is evenly distributed onto the larger area of the reinforced concrete ring beam 63 through the load-bearing diagonal brace 39, reducing the compressive strength per unit area. Referring again to Figure 6 , the column with a larger cross-sectional area at the upper part of the load-bearing diagonal brace 39 near the sector reciprocating push plate and its frame 43 changes into a vertical solid thick strip steel and is reinforced by a reinforcing rib 59 to reduce the width and avoid collision with the moving sector reciprocating push plate and its frame 43. The solid thick strip steel is welded at the axis of the bottom surface of the cross beam 38, and the auxiliary diagonal brace 52 is also connected to the bottom surface of the cross beam 38 near the furnace bottom sealing steel shell 57 in this structure. The lower end of the auxiliary diagonal brace 52 is welded to the force transmission embedded iron on the upper surface of the secondary pouring ring 54, shortening the force transmission span of the cross beam 38 and improving the bearing capacity of the cross beam 38. The outer end of the cross beam 38 passes through the furnace bottom sealing steel shell 57 and is continuously welded and sealed with the furnace bottom sealing steel shell 57. Multiple cross beams 38 are integrated into a load-bearing structure at the intersection of the furnace body center with the central burner base 35.

[0053] The upper side of the central burner base 35 is connected to and supports the large-scale air-cooled composite central burner 31. A chevron beam 82 is welded on the top plate of the cross beam 38. One of the chevron beams 82 encloses the central burner lower row gas valve and pipeline 78 and the central burner lower row air valve and pipeline 80, and the adjacent chevron beam 82 encloses the central burner upper row gas valve and pipeline 79 and the central burner upper row air valve and pipeline 81. The outer end of the chevron beam 82 passes through the furnace bottom sealing steel shell 57 and is continuously welded and sealed with the furnace bottom sealing steel shell 57, and the inner end of the chevron beam 82 is connected to the large-scale air-cooled composite central burner 31. Since the cross beam 38, the chevron beam 82, the cooling belt hopper 37, and the furnace bottom sealing steel shell 57 are all welded together, they belong to a stress structure with a small amount of elastic deformation ability.

[0054] The inner shape of the furnace body is divided into a cooling zone, a roasting zone, and a preheating zone from bottom to top. The outer ends of a part of the cross beams 38 are connected with a main cooling air inlet valve and a pipeline 77. Most of the cooling air enters the cross beams 38 through the main cooling air inlet valve and the pipeline 77, and all the important components such as all the cross beams 38, the herringbone beams 82, the large air-cooled composite central burner 31, and the furnace wall ring beam 36 are protected by air cooling through the connecting air paths. Then, the cooling air enters the cooling zone charge column through the discharge material surface 41 between the lower edge of the cooling zone hopper 37 and the fan-shaped reciprocating push plate and its frame 43, and the gaps between the lower edge of the central burner base 35, the lower edge of the cross beam 38, and the fan-shaped reciprocating push plate and its frame 43.

[0055] As Figure 16 shown, in some preferred embodiments, the inner shape of the furnace body is a ten-section blast furnace-like dumbbell shape, including a hearth, a bosh, a shaft, and a throat connected in sequence from bottom to top. The hearth includes a first hearth refractory inner shape 33 with a hearth angle of 71° - 88° and a second steel cooling zone hopper 37 hearth inner shape with a hearth angle of 75° - 88°. Preferably, the hearth angle of the first hearth refractory inner shape 33 is 71° - 85°, and the preferred angle of the second hearth inner shape is 75° - 86°.

[0056] At the bosh, it is mainly the bosh refractory inner shape 32, which is a straight cylinder shape or a round belly shape, and its diameter is larger than that of other parts of the furnace body.

[0057] The shaft includes a shaft upper straight section refractory inner shape 19, a shaft expansion section refractory inner shape 20, a shaft middle straight section refractory inner shape 22, a shaft contraction section refractory inner shape 23, and a shaft lower section refractory inner shape 24 connected in sequence from top to bottom. The shaft expansion angle of the shaft expansion section refractory inner shape 20 is 70° - 88°, and the preferred range is 76° - 86°; the shaft middle straight section refractory inner shape 22 is a conical inner shape that is straight or close to straight with a smaller upper part and a larger lower part, and the shaft angle of the conical inner shape is greater than 86°, which is the main part of the shaft; the shaft angle of the shaft contraction section refractory inner shape 23 is 70° - 86°, and the preferred range is 76° - 82°; the shaft angle of the shaft lower section refractory inner shape 24 is 55° - 82°, and the preferred range is 60° - 72°, so that the overall shaft forms a gradually outwardly expanding trumpet-shaped structure.

[0058] The throat includes a throat straight section refractory inner shape 16 and a throat contraction section refractory inner shape 18 connected in sequence from top to bottom. A furnace top waste gas outlet 11 is provided at the upper part of the throat straight section refractory inner shape 16. The angle of the throat contraction section refractory inner shape 18 is 45° - 86°, and the preferred angle is 65° - 76°. The preset furnace top edge material surface line is near the lower edge of the throat contraction section refractory inner shape 18.

[0059] Preferably, there are two sections of the furnace throat, five sections of the furnace body, one section of the furnace waist, and two sections of the furnace belly. The furnace throat and the upper part of the furnace body form an upper dumbbell-shaped structure with a thin upper and lower ends and a thick middle part; the middle part of the furnace body is a refractory inner shape of a straight cylinder section of the furnace body or a tapered inner shape that is close to a straight cylinder and is thick at the bottom and thin at the top, forming the middle part of the dumbbell-shaped structure; the lower part of the furnace body is a lower expansion type structure with a gradually decreasing furnace body angle. The lower part of the furnace body, the furnace waist, and the furnace belly together form a lower dumbbell-shaped structure with a thin upper and lower ends and a thick middle part.

[0060] The diameter ratio of the refractory inner shape 19 of the straight cylinder section of the upper part of the furnace body of the upper dumbbell-shaped structure to the refractory inner shape 32 of the furnace waist of the lower dumbbell-shaped structure is 0.8 - 0.9. The diameter ratio of the refractory inner shape 22 of the straight cylinder section of the middle part of the furnace body to the refractory inner shape 32 of the furnace waist is 0.78 - 0.86.

[0061] The above-mentioned ten-section type blast furnace dumbbell-shaped furnace type is suitable for the characteristics of low thermal conductivity of newly formed lime layer and slow combustion of low calorific value gas, prolongs the preheating time of the raw materials just entering the furnace and the cooling time of the finished products, reduces the furnace body height in the preheating zone and the cooling zone, saves the gas pressure difference in these two places, improves product quality, and saves energy and reduces emissions.

[0062] Another major difference between the inner shape of the furnace body of the present invention and the inner shape of the blast furnace is that in the field of kilns without a melting process involved in this patent, the diameter of the furnace waist mainly reflects the performance of the cooling zone and has less impact on the overall performance of the kiln; while the diameter D of the refractory inner shape 22 of the straight cylinder section in the middle of the furnace body (or the lower edge diameter of the tapered inner shape that is close to a straight cylinder and is thick at the bottom and thin at the top with a furnace body angle greater than 86°) has a greater impact on the overall performance of the kiln and is the main part of the roasting zone of this patent. Therefore, in this patent, the diameter D of the refractory inner shape 22 of the straight cylinder section in the middle of the furnace body is used to replace the diameter of the furnace waist of the blast furnace as the expression of the height-diameter ratio of the furnace type; the effective height H of the inner shape of the furnace body is defined as the vertical distance between the lower edge of the multi-tube distributor 12 and the lower edge of the cooling zone hopper 37 at the lower part of the furnace type as the effective height of the inner shape of the furnace body; after optimization, the ratio of the effective height H of the inner shape of the furnace body to the diameter D of the refractory inner shape 22 of the straight cylinder section in the middle of the furnace body is 5.5 - 6.2.

[0063] Such as Figure 16 and Figure 18As shown, in some preferred embodiments, there are various types of side burners. At the lower part of the refractory inner shape 24 of the lower section of the furnace body, a temperature-adjusting air outlet 29 is arranged, and a combined national well side burner 28 is arranged at its upper part. Preferably, the number of the combined national well side burners 28 is one to three rows. At the lower part of the refractory inner shape 23 of the furnace body contraction section, an independent national well side burner and a temperature-adjusting air spray gun 26 are arranged from bottom to top. The independent national well side burner is divided into a fourth row side burner 27 and fifth to seventh row side burners 25. The temperature-adjusting air spray gun 26 is divided into an upper temperature-adjusting air spray gun and a lower temperature-adjusting air spray gun. Among them, the lower temperature-adjusting air spray gun is clamped between the fourth row side burner 27 and the fifth row side burner, and the upper temperature-adjusting air spray gun is clamped between the fifth row side burner and the sixth row side burner. The temperature-adjusting air outlet 29 is connected to the upper and lower temperature-adjusting air spray guns by heat-resistant steel pipes. The preferred number of the temperature-adjusting air outlet 29 and the upper and lower temperature-adjusting air spray guns is 8 - 60 sets each, and they are evenly distributed in the circumferential direction. In some small TGS lime kilns, the upper temperature-adjusting air spray gun can be cancelled or the temperature-adjusting air spray gun 26 can be cancelled entirely, and it is allowed to replace the combined national well side burner 28 with the first to third row independent national well side burners, and the total number of rows of side burners is also allowed to be reduced accordingly; the preferred number of each row of side burners is 8 - 60 sets, and they are evenly distributed in the circumferential direction.

[0064] In some preferred embodiments of the combustion system, referring to Figure 22 and Figure 23 , the first to third row side burners are combined national well side burners 28. The combined national well side burner 28 belongs to a stacked structure from bottom to top, including: a combined side burner first row air channel 2801, a combined side burner first row gas channel 2802, a combined side burner second row air channel 2803, a combined side burner second row gas channel 2804, a combined side burner third row air channel 2805, a combined side burner third row gas channel 2806, a peephole 2807, a combined side burner national well blade 2808, a combined side burner outer sleeve 2809, etc.; among which, the combined side burner second row gas channel 2804 is two round pipes inserted on both sides of the combined side burner second row air channel 2803; the combined side burner first row gas channel 2802 and the combined side burner third row gas channel 2806 with larger flow rates are separated into a grid state by a horizontal rib plate and more than three vertical rib plates; other channels with smaller flow rates are also separated into a grid shape by several vertical rib plates. The combined side burner national well blade 2808 is welded near all the air and gas ejection ports; peepholes 2807 are set at the ends of each channel outside the furnace. The continuous welding with the steel shell 30 of the lower section of the furnace body is realized by the combined side burner outer sleeve 2809. The upper edge of the inner side of the combined national well side burner 28 is flush with the refractory inner shape 24 of the lower section of the furnace body, and the lower edge retracts 30 - 60 mm into the refractory inner shape 24 of the lower section of the furnace body, and this place is transitioned with a slope to prevent furnace charge accumulation.

[0065] Referring again to Figure 24 and Figure 25, the fourth row of side burners 27 and the fifth to seventh row of side burners 25 are all independent national well type side burners, including: independent side burner connecting three flanges 2701, independent side burner combustion air channel 2702, independent side burner connecting two flanges 2703, independent side burner gas channel 2704, independent side burner national well blades 2705 and peepholes 2807. The independent side burner gas channel 2704 is located in the center of the independent side burner. A peephole 2807 is provided at the outer end. Independent side burner national well blades 2705 are welded both inside and outside near the inner ejection port, and the inner ejection port is indented 15 - 30 mm compared to the outer sleeve. An annular channel is formed between the independent side burner gas channel 2704 and the outer sleeve of the independent national well type side burner, and this annular channel is the independent side burner combustion air channel 2702. The upper edge of the inner side of the independent national well type side burner is flush with the inner shape of the refractory material in the furnace body contraction section 23, and the lower edge is recessed 30 - 80 mm inside the inner shape of the refractory material in the furnace body contraction section 23. At the same time, this part is transitioned with a slope to prevent the accumulation of furnace charge.

[0066] Refer again to Figures 19 to 21 , the large - scale air - cooled composite type central burner 31 includes: central burner top plate 3101, central burner lower row burners 3102, central burner upper row burners 3103, central burner vertical stiffening plates 3104, central burner annular stiffening plates 3105, central burner cooling air partition plate 3106, central burner cooling air upward chamber 3107, central burner cooling air downward chamber 3108, central burner refractory outer shape 3109, central burner conical cylinder 3110, central burner national well blades 3111 and central burner base 35, etc.; The cross beam 38 is assembled and installed with a central burner base 35 at the central part of the furnace body. Above the central burner base 35, a central burner conical cylinder 3110 and a central burner cooling air partition plate 3106 are welded. The central burner cooling air partition plate 3106 is located inside the central burner conical cylinder 3110. Central burner vertical stiffening plates 3104 are evenly distributed on the outer side wall of the central burner conical cylinder 3110. The upper edge of the central burner conical cylinder 3110 is continuously welded with the central burner top plate 3101. One layer of central burner annular stiffening plates 3105 is continuously welded at a certain height interval outside the central burner conical cylinder 3110. A certain thickness of refractory material is cast outside the central burner conical cylinder 3110, and the central burner conical cylinder 3110, central burner vertical stiffening plates 3104, central burner annular stiffening plates 3105 and central burner top plate 3101 with anchor bolts welded on their outer surfaces are wrapped into it, forming the central burner refractory outer shape 3109. The central burner cooling air partition plate 3106 divides the central burner conical cylinder 3110 into a central burner cooling air upward chamber 3107 and a central burner cooling air downward chamber 3108 through the central axis. There is a certain gap between the central burner cooling air partition plate 3106 and the central burner top plate 3101, so that the cooling air in the central burner cooling air upward chamber 3107 can turn into the central burner cooling air downward chamber 3108 in this gap to complete the cooling protection of the entire central burner conical cylinder 3110.

[0067] At the upper part of the central burner conical cylinder body 3110, there are branch burners of the central burner, and each branch burner of the central burner is independently connected to a gas pipeline and a combustion-supporting air pipeline. More preferably, at the upper part of the central burner conical cylinder body 3110, there are upper row burners 3103 and lower row burners 3102 of the central burner. The elevation of the lower row burners 3102 of the central burner = the elevation of the lower edge of the combined national well side burner 28 ± 200 mm, and the elevation of the upper row burners 3103 of the central burner = the elevation of the independent national well type side burner ± 200 mm.

[0068] The upper row gas valve and pipeline 79 and upper row air valve and pipeline 81 of the central burner independently connected to each upper row burner 3103 of the central burner, or the lower row gas valve and pipeline 78 and lower row air valve and pipeline 80 of the central burner independently connected to the lower row burners 3102 of the central burner. When these pipelines reach the lower part of the central burner conical cylinder body 3110, they bend and are laid on the upper side of the cross beam 38. Then, a herringbone beam 82 is fixedly welded above the cross beam 38. One end of the herringbone beam 82 is welded to the bottom of the central burner conical cylinder body 3110. The herringbone beam 82 wraps the combustion-supporting air pipe and the gas pipe and passes through the furnace bottom sealing steel shell 57 together, and is continuously welded and sealed here. Preferably, the preferred number of the lower row burners 3102 and the upper row burners 3103 of the central burner is 4 - 8 sets, and they are evenly distributed in the circumferential direction. In some embodiments, the lower row burners 3102 of the central burner can be cancelled in a small TGS lime kiln.

[0069] The upper part of the furnace body is the furnace throat section. There is a furnace throat roof plate 9 at the top of the furnace throat. A furnace top bin and a feeding structure are arranged on the furnace throat roof plate 9. There is a refractory insulation layer below the furnace throat roof plate 9.

[0070] As Figure 1 and Figure 26 shown, the feeding structure includes a furnace top receiving hopper 1, a variable-speed spiral feeder 3 and a multi-tube feeder 12. There is a bin skeleton 5 for supporting the bin shell in the furnace top bin 4. There is a furnace top support frame 2 for supporting the furnace top receiving hopper 1 above the furnace top bin 4. The furnace top support frame 2 supports the furnace top receiving hopper 1 above the variable-speed spiral feeder 3. The main chamber of the furnace top bin 4 is below the variable-speed spiral feeder 3. An air-cooled bottom plate 6 is installed at the bottom of the furnace top bin 4. The multi-tube feeder 12 is hung below the air-cooled bottom plate 6. The multi-tube feeder 12 connects the furnace top bin 4 with the furnace throat. The furnace top receiving hopper 1, the variable-speed spiral feeder 3, the furnace top bin 4 and the multi-tube feeder 12 are serially arranged from top to bottom on the furnace top central axis. The feeding effect of a large lime kiln is improved through two times of feeding by the variable-speed spiral feeder 3 (the first feeding in the furnace top bin 4) and the multi-tube feeder 12 (the second feeding at the lower part of the furnace throat).

[0071] As Figure 29As shown in the figure, the variable-speed spiral distributor 3 includes a central throat pipe 301, a variable-frequency motor 302, a variable-speed and rotary support system device 303, a distributing chute 305 and connecting parts. The lower end of the top charging hopper 1 of the furnace is connected to the upper end of the central throat pipe 301, and the lower end of the central throat pipe 301 is connected to the distributing chute 305 through the connecting parts. The variable-speed spiral distributor 3 conducts primary charging in the top bin 4 of the furnace. By continuously increasing the rotation speed of the distributing chute 305, the horizontal component of the initial oblique throwing velocity of the raw materials leaving the end of the distributing chute 305 is continuously increased, forming an effect of disk-shaped multi-ring distribution similar to mosquito coils. Among them, the variable-frequency motor 302 and the variable-speed and rotary support system device 303 need to increase the power and structural strength on the basis of the existing technology.

[0072] Preferably, the connecting parts are composed of a trunnion 306, a connecting chain 307, etc. The trunnion 306 is fixed on the outer wall of the central throat pipe 301, and one end of the distributing chute 305 is hung by the trunnion 306. One end of the connecting chain 307 is hinged on the other side of the outer wall of the central throat pipe 301, and the other end of the connecting chain 307 is hinged to the middle or lower part of the distributing chute 305. Preferably, when the particle size distribution area of the raw materials is too wide and polarized seriously, a sieve bar 308 is installed at the rear part of the bottom plate of the distributing chute 305 to play a role in screening the raw materials, distributing the materials with smaller particle sizes directly below the cloth throat pipe 1201, and at a fixed point position in the middle and inner part of the furnace throat radius. Preferably, sealing strips 304 are provided at the relative movement interfaces between the central throat pipe 301 and the top plates of the top charging hopper 1 and the top bin 4 of the furnace to ensure the sealing performance of the top bin 4 of the furnace.

[0073] The multi-pipe distributor 12 is an assembly of multiple cloth throat pipes 1201. These cloth throat pipes 1201 are all hoisted and fixed on the air-cooled bottom plate 6 of the top bin 4 of the furnace. The length of the cloth throat pipe 1201 gradually shortens from the center of the furnace throat to the edge according to the material line stacking angle. By adjusting the insertion depth of the cloth throat pipe 1201, the ratio of the central air flow to the edge air flow is optimized and adjusted. Utilizing the funnel effect, a small part of the materials with a large powder content are distributed to the preset positions in the furnace at each point corresponding to each cloth throat pipe 1201, and burners are arranged here for forced heating. The furnace materials in other parts are more uniform in particle size, improving the overall air permeability, saving the air flow pressure loss, and improving the temperature distribution in the furnace.

[0074] Preferably, as long as there is no serious shortage of materials in the top bin 4 of the furnace, when the TGS lime kiln discharges materials, the materials will automatically be replenished into the furnace through the multi-pipe distributor 12 to complete the secondary charging, ensuring that the top surface of the furnace 13 (at the furnace throat) is constant, and only the height of the material surface in the top bin 4 of the furnace fluctuates within the set range. The height area of the multi-pipe distributor 12 is a stable free space. Multiple top furnace waste gas outlets 11 are provided on the furnace wall of the furnace throat corresponding to this height, which is beneficial to the uniform distribution and smooth discharge of the waste gas in the furnace body, and the top of the furnace is controlled to be in a slightly negative pressure state by using an induced draft fan.

[0075] Preferably, the distribution pattern of the cloth throat pipes 1201 on the air-cooled bottom plate 6 is a single ring (as shown in Figure 1 and Figure 26 ), multiple rings of two or more rings (such as Figure 27 and Figure 28 which shows a two-ring multi-pipe distributor), a quadrilateral grid or a triangular grid, etc., as long as it can ensure the rationality of the air flow distribution and the constancy of the top surface of the furnace charge 13 remains unchanged.

[0076] Preferably, the cross-section of the cloth throat pipe 1201 is a horseshoe shape, a trapezoid, an ellipse or a rectangular structure, so that the air flow in the furnace overflows more smoothly. The material in the cloth throat pipe 1201 is at room temperature, has a material sealing effect, and there is a small amount of room temperature air moving downward under the action of a slight negative pressure in the furnace throat, so as to protect the cloth throat pipe 1201 from oxidation, and at the same time ensure that the variable-speed spiral distributor 3 is in a room temperature and normal pressure environment, reduce the sealing requirements, improve the service life, and make the debugging, maintenance and replacement safe and convenient, and also improve the environmental protection status of the furnace top.

[0077] A cooling interlayer for flowing protective air is provided between the air-cooled bottom plate 6 and the top plate 9 of the furnace throat. The two ends of the cooling interlayer are respectively provided with a top protection air outlet 8 and a top protection air inlet 7; or an air-cooling channel is arranged on the air-cooled bottom plate 6, so as to reduce the temperature of the top plate 9 of the furnace throat and / or the bottom plate of the top bin 4 of the furnace, prevent it from being burned out and oxidized, and play a role in enhancing the bearing capacity of the bottom plate of the top bin of the furnace 4.

[0078] Production process: The qualified raw materials after screening are transported to the top of the furnace by a known inclined bridge trolley (or belt conveyor, bucket elevator, etc.) under the control of intelligent software and hardware. Before reaching the top of the furnace, the variable-speed spiral distributor 3 is started and rotated at a constant speed with a preset initial speed. When the raw materials are poured into the receiving funnel 1 at the top of the furnace, they immediately start to rotate at an accelerated speed with a preset acceleration, and the raw materials are distributed into the top bin 4 of the furnace until the rotation stops after a cloth feeding process is completed. Due to the continuous change of the oblique throwing initial speed of the raw materials leaving the cloth chute 305, a disk-shaped multi-ring cloth feeding effect similar to mosquito coils is formed at the material surface in the top bin 4 of the furnace, replacing the complex inclination adjustment mechanism of the blast furnace spiral distributor.

[0079] When the lime kiln discharges materials below, the raw materials in the top bin 4 of the furnace are immediately automatically replenished into the furnace, and through the funnel effect of the multi-pipe distributor 12, the furnace charge is cloth-fed twice, further improving the cloth feeding effect.

[0080] The furnace charge begins the feeding movement. Under the conditions of complete countercurrent heating and reaction, and under the heating of a uniform hot air stream, after drying, preheating, roasting, decomposition, and cooling, it descends to the upper surface of the sector reciprocating push plate and its frame 43. The power device 49 drives the sector reciprocating push plate and its frame 43 to perform horizontal reciprocating movements. The material layer between it and the lower edge of the cooling belt hopper 37 is quantitatively and evenly discharged into the furnace bottom aggregate hopper 64. Its working principle is the same as that of a reciprocating feeder. Then, it passes through the upper hydraulic seal discharge valve 72, the discharge intermediate funnel 71, and the lower hydraulic seal discharge valve 68 and is discharged outside the furnace. The alternating coordinated operation of the upper hydraulic seal discharge valve 72, the lower hydraulic seal discharge valve 68, the pressure relief pipeline 73, the pressure relief valve 74, and the micro-dust collector 75 ensures a good environmental protection state in the furnace bottom area during the entire discharging process. The highly active lime discharged outside the furnace is transported to the finished product treatment system by a sealed belt.

[0081] The cooling air first completes the cooling protection of the furnace bottom air box, the bearing beam, the large air-cooled composite central burner, and the furnace wall ring beam 36, and at the same time recovers the heat. Then, it enters the cooling belt material column through the material gaps between the cooling belt hopper 37, the cross beam 38, and the lower edge of the central burner base 35 and the sector reciprocating push plate and its frame 43, and then passes upward through the gaps between the material blocks to cool the material blocks. When all the cooling air reaches the lower edge of the inner lining of the lower section of the furnace body 24, its temperature has risen above 400°C. Here, a part of the hot cooling air is led out as the temperature regulating air through the temperature regulating air outlet 29 and sent upward to the upper and lower temperature regulating air spray guns 26 and then sprayed into the furnace to participate in combustion. The remaining part of the hot cooling air continues to rise in the material column and enters the roasting zone to also participate in combustion, reducing the combustion air excess coefficient of the entire furnace in this process and improving the energy utilization rate. The combustion-supporting air and low-calorie gas are preheated to 180 - 260°C by a large-scale waste heat recovery device installed outside the furnace, and then adjusted and metered respectively before being sent to their respective annular pipes. Then, they are respectively sent to the large air-cooled composite central burner 31, the fifth to seventh row side burners 25, the fourth row side burner 27, and the combined Guojing side burners 28 in the first to third rows through their respective branch pipes and valves. Different from the high-calorie gas and high-temperature fast-burning roasting theory of other lime roasting kilns and processes, the R & D team first proposed and adopted the three-low roasting theory of low-calorie gas, low temperature, and low air excess coefficient, which is an enrichment and development of the lime roasting theory. And through these Guojing side burners and the large air-cooled composite central burner 31, they are sprayed into the gaps of the charge column in the furnace for mixing and combustion, forming an inside-out opposite combustion, increasing the penetration ability of the flame, solving the edge effect problems inherent in other vertical kilns, such as insufficient central air flow, excessive edge air flow, too low middle temperature, and too high edge temperature, being conducive to the large-scale of the kiln. The temperature in the main area of the roasting zone can be controlled at 1050 - 1120°C, and the tiny area of the highest temperature will not exceed 1250°C in the short term, and the oxygen partial pressure there is very low. It not only forms a uniformly distributed flame waste gas, uniformly provides the heat for roasting the charge, and makes the temperature distribution more uniform, but also eliminates the thermodynamic conditions for the generation of NOx. And low-calorie gases such as blast furnace gas and converter gas originally contain much less sulfur than coal, reducing the total amount of pollutants generated from the source. Without the need to equip desulfurization and denitration equipment, it can meet the ultra-low emission standards. This is the theoretical innovative contribution of the R & D team, including the previously applied TCS circular pellet roasting shaft furnace, to the large-scale of the shaft furnace. Currently, the daily output of the 900-ton-per-day blast furnace gas TGS lime kiln put into production by the R & D team is more than 150 tons larger than that of the patented large-scale Maerz lime kiln using high-calorie gas abroad. This TGS lime kiln is also conducive to the production of low-silicon, low-sulfur, and high-reactivity lime, laying a solid foundation for reducing the lime consumption per ton of steel.

[0082] The roasting flame and waste gas of the present invention move upward while burning along the gaps of the charge column in the furnace. After completing the roasting, preheating, and drying of the charge, they overflow from the top surface 13 of the charge and enter the free space at the top of the furnace, and then are discharged outside the furnace through the waste gas outlet 11 at the top of the furnace.

[0083] Finally, it should be noted that the above-listed are only the preferred embodiments of the present invention. Of course, those skilled in the art can make changes and modifications to the present invention. If these modifications and variations fall within the scope of the claims of the present invention and its equivalent technologies, they should be considered within the protection scope of the present invention.

Claims

1. A central burner lime kiln, comprising a furnace body, a material distribution structure, a combustion system, a sealed discharge structure and a furnace bottom sealed load-bearing structure; characterized in that: The furnace body is shaped like a dumbbell of a blast furnace, consisting of the throat, body, waist and belly connected in sequence from top to bottom. A top silo and a distribution structure are set above the throat. The distribution structure distributes the charge twice, in the top silo and throat respectively, to improve the distribution effect of the lime kiln. A sealed load-bearing structure is provided under the furnace belly. The sealed load-bearing structure supports the inner shape of the furnace body and the sealed discharge structure. The sealed discharge structure includes a reciprocating push plate and a bottom collecting hopper. The discharge amount inside the kiln body is controlled by controlling the reciprocating motion frequency of the reciprocating push plate, and the cumulative error of each discharge height is controlled to be stable within the set range within the effective height range of the lime kiln. The combustion system includes a large air-cooled composite central burner and side burners. The large air-cooled composite central burner and the side burners form inside-outside combustion, so that the flame covers the entire furnace cross section and improves the temperature uniformity of the lime kiln.

2. The central burner lime kiln according to claim 1, characterized in that: The sealed load-bearing structure of the furnace bottom includes a bunker-type reinforced concrete foundation, a reinforced concrete ring beam, a first-floor concrete foundation platform, a secondary casting ring, and a sealed force transmission system. A reinforced concrete ring beam is cast on the bunker-type reinforced concrete foundation, and a sealed force transmission system is installed on the reinforced concrete ring beam. The sealed force transmission system is divided into four parts. The first sealed force transmission system includes support columns, furnace bottom sealing steel shell, connecting plates and furnace wall ring beam. The support columns are fixed on the upper surface of the reinforced concrete ring beam, and the furnace bottom sealing steel shell is set on the outside of the support columns. The connecting plates connect the furnace bottom sealing steel shell and the support columns to form a truss-like integral ring column structure, which is connected to and supports the furnace wall ring beam. The furnace body is connected and supported on the furnace wall ring beam. The lower part of the furnace bottom sealing steel shell and the support columns is fixed in the secondary casting ring. The secondary casting ring is located at the intersection of the inner side of the first platform of the concrete foundation and the upper surface of the reinforced concrete ring beam, and is fixedly connected to the two and integrated into one. The second sealing and force transmission system includes an annular pre-buried iron and a furnace bottom bellows. These are fixed to the inner side of the reinforced concrete ring beam. The upper side of the pre-buried iron is connected to a furnace bottom collecting hopper, which is inserted into the furnace bottom bellows. The lower part of the hopper is connected to the furnace bottom discharge intermediate funnel, the lower end of which is connected to the upper hydraulically sealed discharge valve, which in turn is connected to the lower hydraulically sealed discharge valve. The furnace bottom discharge intermediate funnel is also connected to a micro-dust collector and an external exhaust gas dust removal system. Under furnace pressures above 50 kPa, this ensures the smooth opening of the upper and lower hydraulically sealed discharge valves and protects the furnace bottom area during discharge. The third sealed force transmission system includes a guide device, rollers, and a reciprocating push plate. The guide device and rollers are connected to the reinforced concrete ring beam. The guide device and rollers are both dynamically connected to the reciprocating push plate to support and ensure the reciprocating push plate to move back and forth along the set trajectory. The outer side of the reciprocating push plate is connected to a power device, which drives the reciprocating push plate to achieve reciprocating motion. The fourth sealed power transmission system includes a power transmission chassis, load-bearing diagonal braces and a load-bearing beam. The power transmission chassis is fixed on the reinforced concrete ring beam, the load-bearing diagonal braces are fixed on the power transmission chassis, the load-bearing diagonal braces are fixed on the load-bearing beam, and a large air-cooled composite central burner base is fixed in the center of the load-bearing beam. The furnace bottom bellows, load-bearing beams, large air-cooled composite center burners, and furnace wall ring beams are all equipped with cooling air protection pipelines.

3. The center burner lime kiln according to claim 2, characterized in that: The large air-cooled composite center burner includes a center burner conical cylinder and a center burner support burner. The center burner conical cylinder and the center burner cooling air baffle are fixed on the center burner base. The center burner cooling air baffle divides the center burner conical cylinder into a center burner cooling air upflow chamber and a center burner cooling air downflow chamber through the center axis. A gap is left between the center burner cooling air baffle and the center burner top plate so that the cooling air in the center burner cooling air upflow chamber can be transferred to the center burner cooling air downflow chamber through this gap, completing the cooling protection of the entire center burner conical cylinder; refractory material is also cast outside the center burner conical cylinder to form a frustoconical refractory material shape; The load-bearing beams include a cross beam and a herringbone beam. The upper part of the conical cylinder of the central burner is provided with the branch burners of the central burner. The port of each branch burner of the central burner is connected to the central burner blade. Each branch burner of the central burner is independently connected to the gas pipeline and the combustion-supporting air pipeline. The gas pipeline and the combustion-supporting air pipeline are bent at the lower part of the conical cylinder of the central burner and laid on the upper side of the cross beam. They are wrapped by the herringbone beam and pass through the sealed steel shell of the furnace bottom. The support burners of the center burner are divided into upper and lower rows of burners. The elevation of the lower row of burners of the center burner = the elevation of the first row of side burners ± 200mm, the elevation of the upper row of burners of the center burner = the elevation of the fourth row of side burners ± 200mm. Small TGS lime kilns allow the center burner to have only one row of support burners.

4. The central burner lime kiln according to claim 1, characterized in that: The side walls of the furnace are equipped with side burners, which include combined national well side burners and / or independent national well side burners, and / or temperature-regulating air outlets and temperature-regulating air spray guns; the combined national well side burners are arranged in the middle and lower part of the furnace wall, and the independent national well side burners and temperature-regulating air spray guns are arranged in rows on them, and the temperature-regulating air outlets are arranged below the combined national well side burners.

5. The central burner lime kiln according to claim 4, characterized in that: The combined national well side burner has a stacked structure from bottom to top. Each row of the combined national well side burners is connected to an air channel and a gas channel. The outlet ports of the air channel and the gas channel are both provided with combined side burner national well blades. and / or The independent side burner includes: an independent side burner combustion-supporting air channel, an independent side burner gas channel and an independent side burner side well blade; the independent side burner gas channel is located in the center of the independent side burner, and independent side burner side well blades are fixed inside and outside the ejection port of the independent side burner gas channel, and are retracted 15 to 30 mm from the outer sleeve; an annular channel is formed between the independent side burner gas channel and the outer sleeve of the independent side burner, and the annular channel is the independent side burner combustion-supporting air channel.

6. The central burner lime kiln according to claim 1, characterized in that: The throat and the upper part of the furnace body form an upper dumbbell head structure with thin upper and lower ends and a thick middle part; the middle part of the furnace body is a straight tube section refractory inner profile of the furnace body or a tapered inner profile close to a straight tube that is thin at the top and thick at the bottom, forming the middle part of the dumbbell-shaped structure; the lower part of the furnace body is a lower expansion structure with a gradually smaller furnace body angle. The lower part of the furnace body, the furnace waist and the furnace belly as a whole form a lower dumbbell head structure with thin upper and lower ends and a thick middle part.

7. The central burner lime kiln according to claim 1, characterized in that: The furnace throat includes a furnace throat top plate, a furnace throat straight section refractory inner profile, and a furnace throat contraction section refractory inner profile connected in sequence from top to bottom, and the angle of the furnace throat contraction section refractory inner profile is 45°~86°; and / or The furnace body includes a refractory inner mold of the upper straight section of the furnace body, a refractory inner mold of the furnace body expansion section, a refractory inner mold of the middle straight section of the furnace body, a refractory inner mold of the furnace body contraction section and a refractory inner mold of the lower section of the furnace body, which are connected in sequence from top to bottom. The refractory inner mold of the furnace body expansion section has a furnace body expansion angle of 70° to 88°; the refractory inner mold of the middle straight section of the furnace body or a tapered inner mold that is close to a straight tube and thin at the top and thick at the bottom, the furnace body angle of the tapered inner mold is greater than 86°, and it is the main part of the furnace body; the furnace body angle of the refractory inner mold of the furnace body contraction section is 70° to 86°, and the furnace body angle of the refractory inner mold of the lower section of the furnace body is 55° to 82°, so that the overall furnace body forms a trumpet-shaped structure that gradually expands downward and outward; and / or The inner shape of the furnace waist refractory is straight cylindrical or round belly, and its diameter is larger than the diameter of other parts of the furnace body; and / or The bosh includes a first section of bosh refractory inner profile with a bosh angle of 71° to 88° and a second section of steel cooling belt hopper inner profile with a bosh angle of 75° to 88°; and / or The ratio of the effective height of the furnace body inner profile to the diameter of the lower edge of the refractory inner profile of the straight cylindrical section in the middle of the furnace body is 5.5~6.

2.

8. The central burner lime kiln according to claim 1, characterized in that: The charging structure includes a furnace top receiving funnel, a variable speed spiral distributor, a furnace top silo and a multi-tube distributor; the furnace top receiving funnel, the variable speed spiral distributor, the furnace top silo and the multi-tube distributor are arranged in series from top to bottom at the central axis of the furnace top, the furnace top receiving funnel is fixed above the variable speed spiral distributor, and the main chamber of the furnace top silo is below the variable speed spiral distributor, and the variable speed spiral distributor performs the first charging into the furnace top silo; the bottom of the furnace top silo is equipped with an air-cooled bottom plate, and a multi-tube distributor is hung on the air-cooled bottom plate. The multi-tube distributor connects the furnace top silo with the furnace throat, and the multi-tube distributor performs the second charging to the material surface of the furnace throat. The multi-tube distributor is an assembly of more than two distribution throats, which are hung on the air-cooled bottom plate of the furnace top silo. The length of the distribution throat gradually shortens from the center of the furnace throat to the edge according to the material line stacking angle.

9. A production process for roasting active lime using low calorific value gas, characterized in that: The production process is carried out in the central burner lime kiln according to any one of claims 1 to 8, comprising the following steps: S1. Qualified raw materials are distributed once through the variable speed spiral distributor, forming a disc-shaped multi-ring distribution effect similar to mosquito coils in the furnace top silo; when the central burner lime kiln discharges materials outward, the raw materials in the furnace top silo are automatically fed into the furnace through the multi-tube distributor under the action of gravity, and the materials are distributed twice; S2. The raw materials entering the furnace begin to discharge. Under the complete countercurrent heating and reaction and the heating of uniform hot air flow, they complete drying, preheating, roasting, decomposition, and cooling. Then they fall onto the reciprocating push plate. Through the reciprocating motion of the reciprocating push plate, the cooled furnace charge is quantitatively and evenly discharged into the collecting hopper at the bottom of the furnace and discharged out of the furnace through the sealed discharge valve.

10. The production process for roasting active lime using low calorific value gas according to claim 9, characterized in that: After the cooling air has completed the cooling protection of the furnace bottom bellows, load-bearing beams, large air-cooled composite center burners, and furnace wall ring beams, it then passes through the cooling belt hopper, the load-bearing beams, the gap between the lower edge of the center burner base and the reciprocating push plate into the cooling belt material column, and then passes through the gaps between the material blocks upward through the material column to cool the material blocks; When all the cooling air reaches the lower section of the furnace body, its temperature has risen to above 400℃. Here, part of the hot cooling air is drawn out through the temperature-regulating air outlet as temperature-regulating air, sent upward to the temperature-regulating air spray gun, and then sprayed into the furnace to participate in the combustion; the remaining hot cooling air continues to rise in the material column and enters the roasting zone to participate in the combustion, reducing the excess air coefficient of the entire furnace and improving energy utilization. After being preheated to 180-260℃ outside the furnace, the combustion air and low calorific value gas are sent to the combustion system and sprayed into the gaps of the material column in the furnace through the side burners and the large air-cooled composite central burner for mixing and combustion, forming internal and external combustion to increase the penetration ability of the flame. The roasting flame and exhaust gas move upward along the gaps of the charge column in the furnace while burning. After completing the roasting, preheating and drying of the charge, they overflow the charge surface on the top of the furnace, enter the free space on the top of the furnace, and are then discharged out of the furnace through the exhaust gas outlet on the top of the furnace. The temperature in the main area of the roasting zone is controlled at 1050-1120°C, with the maximum temperature not exceeding 1250°C, and the oxygen partial pressure there is lower than 0.15KPa, forming a uniformly distributed flame exhaust gas.

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