A ceramsite roasting and firing system

Abstract

The present invention discloses a ceramsite roasting and firing system, including a ceramsite roasting kiln and a grate cooler for cooling ceramsite; wherein the ceramsite roasting kiln is a rotary ceramsite roasting kiln, and the feed inlet and the discharge port of the rotary ceramsite roasting kiln are installed at the feed end of the grate cooler at a slope of 2.5%; a temperature measuring device that moves horizontally along the kiln body is provided on the outer wall of the kiln body; the discharge end of the rotary ceramsite roasting kiln is connected to a sealed door cover, and the lower end surface of the door cover is sealed and connected to the feed inlet of the grate cooler. The production of ceramsite using the above-mentioned rotary ceramsite roasting kiln realizes the orderly release of gas-generating substances inside the ceramsite, and obtains ceramsite with different pore structures; the amount of liquid phase on the surface of the ceramsite is increased, the degree of vitrification of the surface of the ceramsite is increased, the water absorption rate is reduced, the surface strength is increased, etc. The cooling capacity is greatly improved by using the grate cooler, the waste heat recovery efficiency becomes higher, and the cooling power consumption is reduced.

Description

Technical Field

[0001] The invention belongs to the technical field of rotary ceramsite roasting kiln and ceramsite roasting, and in particular relates to a ceramsite roasting and firing system. Background Art

[0002] At present, China basically adopts plug-in variable diameter double-drum rotary ceramsite roasting kiln or single-drum long kiln (φ3.5m-65m) for the preparation of ceramsite. This rotary ceramsite roasting kiln integrates material drying, ball making, preheating, roasting and cooling for production. Its advantage is high integration, and its disadvantage is low fuel utilization. The rotary ceramsite roasting kiln is relatively long, resulting in large heat dissipation and high heat consumption of the kiln barrel, and low output due to low filling rate in the kiln, as well as large land occupation and single ceramsite product. The United Kingdom has designed a three-leaf kiln, whose internal high-temperature lining is made of nickel-cadmium alloy, the cross-section is three-leaf type, and the external castable is made of alumina fiber. This three-leaf structure rotary ceramsite roasting kiln is energy-saving and environmentally friendly compared to the traditional rotary ceramsite roasting kiln, but due to the complex appearance structure of the three-leaf kiln with this cross-sectional shape, it is difficult to process, and the thickness of the internal castable is uneven. Under high-temperature working conditions, the thermal stress concentration phenomenon is obvious, which seriously affects its working life.

[0003] A Chinese patent (CN 109539777 A) discloses a rotary ceramsite roasting kiln, wherein the inner wall of the rotary kiln cylinder is stacked with a refractory brick layer, and the refractory brick layer has at least three lifting structures formed by arched protrusions along the axial direction of the cylinder and protruding toward the inner side of the cylinder, and the arched protrusions of the lifting structure protrude from the surface of the refractory brick layer on its side. The patent builds a three-leaf rotary structure along the axial direction in the kiln. The arched lifting structure built with refractory bricks is prone to high wear rate under material impact, and may even fall off, especially when the material is more viscous or when it forms a circle or snowballs, it is more likely to fall off, causing a risk of danger. In addition, the lifting structure is provided with an expansion gap, which is easily blocked when firing larger materials and loses its expansion function, which makes it more likely to cause the arched structure to fall off. In particular, when installing the above-mentioned material turning cylinder, there is always a corner at the connection between the turning cylinder and the inner wall of the cylinder body, and a smooth transition cannot be achieved. Therefore, in the actual production process, this part is prone to material storage problems and is also prone to squeezing and breaking the expanded clay, resulting in poor molding quality and a high breakage rate.

[0004] Chinese invention (CN103575095B) discloses a waterfall type rotary ceramsite roasting kiln, wherein the inner wall of the rotary ceramsite roasting kiln cylinder is provided with at least three material turning cylinders extending along the axial direction of the rotary ceramsite roasting kiln cylinder and arranged along its cross section, wherein each material turning cylinder is formed by splicing a plurality of two-section closed cylinders along the axial direction of the rotary ceramsite roasting kiln cylinder, the middle is hollow, and the cross section of the material turning cylinder is semicircular. This material lifting structure can lift the material to a certain height and then drop it, thereby improving the heat exchange efficiency of the material. However, when the material turning cylinder is installed on the inner wall of the rotary ceramsite roasting kiln cylinder, there is always a corner portion at the connection part between the turning cylinder and the inner wall of the cylinder, and a smooth transition cannot be achieved. Therefore, in the actual production process, this part is prone to material storage problems, and the ceramsite is also easily squeezed and broken, so its molding quality is poor and the breakage rate is high.

[0005] The Chinese invention (CN 113834320 A) discloses a rotary ceramsite roasting kiln for calcining ceramsite, wherein the inner wall layer of the rotary ceramsite roasting kiln cylinder is provided with a plurality of grooves extending axially and evenly distributed along the rotary ceramsite roasting kiln cylinder, and the inner wall layer is also provided with a plurality of protrusions extending axially and evenly distributed along the rotary ceramsite roasting kiln cylinder, the cross sections of the protrusions and the grooves are both arc-shaped, the protrusions and the grooves are alternately arranged and the adjacent protrusions and grooves have a smooth transition, the depth of the grooves is much greater than the height of the protrusions and the angle of the arc of the groove cross section is much greater than the angle of the arc of the protrusion cross section. In this patent, the kiln cylinder is full of grooves or protrusions, which limits the kiln's rotation speed to a very slow level. The residence time of the expanded clay raw material in the kiln is relatively long, which will result in high energy consumption and low thermal efficiency. Since there is no buffering material in the grooves, the particle breakage rate will be high, especially when the expanded clay raw material just enters the grooves from the tail of the kiln. The material residence time is relatively long, resulting in a high breakage rate of the raw material particles, and the increase of smoke and dust at the tail of the kiln makes subsequent treatment difficult.

[0006] In addition, the existing technology for cooling expanded clay mostly adopts single-drum coolers and vertical coolers, which cannot effectively recover the heat of expanded clay clinker and have low cooling efficiency, especially when the specification of rotary kiln becomes larger, they cannot effectively cool expanded clay clinker and cannot effectively recover the heat at the kiln head to make up for the insufficient waste heat at the kiln tail for drying expanded clay raw balls. Summary of the invention

[0007] In view of the problems existing in the prior art, the present invention provides a ceramsite roasting and firing system.

[0008] The present invention is implemented in this way. A ceramsite roasting and firing system includes a ceramsite roasting kiln, which is characterized by: also including a grate cooler for cooling ceramsite; wherein the ceramsite roasting kiln is a rotary ceramsite roasting kiln, and the feed inlet and the discharge port of the rotary ceramsite roasting kiln are installed at the feed end of the grate cooler with a slope of 2.5%; a temperature measuring device that moves horizontally along the kiln body is provided on the outer wall of the kiln body; the discharge end of the rotary ceramsite roasting kiln is connected to a sealed door cover, and the lower end surface of the door cover is sealed and connected to the feed inlet of the grate cooler.

[0009] Preferably, the rotary expanded clay roasting kiln comprises a kiln body, the inner wall of the kiln body is provided with a refractory layer from the kiln head to the kiln tail, and is characterized in that: the kiln body is composed of a material blocking check zone and a rapid roasting zone from the feed end to the discharge section, a material feeding constriction is provided on the feed port side of the material blocking control zone, a material blocking boss is provided in the middle of the material blocking zone, and the rapid combustion zone is provided with three or more arch height portions of curved surface structures along the circumferential direction of the kiln body; and a discharge constriction is provided in the discharge section of the rapid roasting zone.

[0010] Preferably, both the inlet constriction and the outlet constriction are provided with inward guide slopes.

[0011] Preferably, the height of the material-blocking boss is not greater than 1 / 2 of the height of the arched portion.

[0012] Preferably, the rotary expanded clay roasting kiln comprises a kiln body, the inner wall of the kiln body is provided with a refractory layer from the kiln head to the kiln tail, the kiln body is composed of a preheating and denitrification zone, a shaping and control zone and a rapid calcination zone from the feeding end to the discharging section, the cross-sectional area in the kiln body decreases successively from the preheating and denitrification zone, the shaping and control zone and the rapid calcination zone, and a plurality of annular protrusions for prolonging the residence time of the material and regulating the orderly release of the gas-generating substances inside the expanded clay are provided in the shaping and control zone along the axial direction of the kiln body, and a receiving groove for filling the active substance is formed between adjacent annular protrusions; the rapid combustion zone is provided with three or more arch height portions with curved surface structures along the circumferential direction of the kiln body.

[0013] Preferably, the cross-sectional area of ​​the shaping and regulating zone is 70% to 80% of the cross-sectional area of ​​the preheating and denitrification zone; and the cross-sectional area of ​​the rapid calcination zone is 50% to 60% of the cross-sectional area of ​​the preheating and denitrification zone.

[0014] Preferably, the length of the kiln body is L; the length of the preheating and denitrification zone is less than or equal to 0.3L; the length of the shaping and regulating zone is 0.25-0.4L; and the length of the rapid calcination zone is 0.3-0.45L.

[0015] Preferably, the distance between each two adjacent annular protrusions is 2-4 times the height of the annular protrusions, the height of each annular protrusion is 0.05-0.1 times the kiln radius, and the width of the root of the annular protrusion is 1-2.5 times the height.

[0016] Preferably, the height of the annular protrusion is the same from the feeding direction to the discharging direction or increases linearly along the moving direction of the ceramsite.

[0017] Preferably, the curve of the arch height portion changes to y=x n function of , where n is any real number, n>0.

[0018] Advantages and technical effects of the present invention: The present invention adopts the above technical solution and has the following advantages:

[0019] 1. By adding the design of the non-return area of ​​ceramsite material blocking, the backflow is prevented while the gas-generating substances inside the ceramsite are released in an orderly manner, and ceramsite with different pore structures and stacking densities is obtained; at the same time, the breakage rate of ceramsite is reduced.

[0020] 2. Through the design of the rapid roasting area, the amount of liquid phase on the surface of the ceramsite is increased, the degree of vitrification of the surface of the ceramsite is improved, the water absorption rate is reduced, and the surface strength is improved.

[0021] 3. The grate cooler is used to replace the traditional single-drum cooler and vertical cooler. Its cooling capacity is greatly improved, the waste heat recovery efficiency is higher, and the cooling power consumption is reduced.

[0022] Therefore, by optimizing the internal structure design of the rotary ceramsite roasting kiln, efficient and rapid ceramsite production is achieved, and the productivity of ceramsite is improved; the internal structure design of the ceramsite kiln and the production method of the present invention have high application value and promotion value, and have broad market prospects in the field of ceramic production. BRIEF DESCRIPTION OF THE DRAWINGS

[0023] Figure 1 It is a structural schematic diagram of embodiment 1 of the present invention;

[0024] Figure 2 This is a schematic diagram of the structure of a ceramsite roasting kiln in Example 1;

[0025] Figure 3 yes Figure 2 Middle AA section view;

[0026] Figure 4 yes Figure 2 Middle BB section view;

[0027] Figure 5 It is a schematic diagram of the structure of the ceramsite roasting kiln in Example 2;

[0028] Figure 6 yes Figure 5 Middle AA section view;

[0029] Figure 7 yes Figure 5 Middle BB section view;

[0030] Figure 8 yes Figure 5 Middle CC section view.

[0031] In the figure, 100, ceramsite roasting kiln; 200, grate cooler; 300, temperature measuring device; 400, sealed door cover;

[0032] 1. Kiln body; 101. Material blocking non-return zone, 111. Material blocking boss; 102. Rapid roasting zone; 103. Feeding necking; 104. Arch height; 105. Discharging necking; 106. Diversion slope; 121. Preheating and denitrification zone; 122. Shaping and control zone; 123. Rapid calcination zone; 124. Annular protrusion; 125. Accommodating groove; 126. Arch height; 2. Refractory layer; DETAILED DESCRIPTION

[0033] In order to make the purpose, technical solution and advantages of the present invention more clearly understood, the present invention is further described in detail below in conjunction with the embodiments. It should be understood that the specific embodiments described herein are only used to explain the present invention and are not used to limit the present invention.

[0034] Example 1, please refer to Figures 1 to 4 A ceramsite roasting and firing system includes a ceramsite roasting kiln 100 and a grate cooler 200 for cooling ceramsite; in the field of ceramsite roasting technology, the grate cooler is used for the first time and is usually used in cement clinker. Since the liquid phase of cement clinker is mostly large lumps, while the ceramsite is fired with very little liquid phase and basically no lumps, the existing grate cooler is modified and the rolling device at the discharge port of the grate cooler is cancelled. Since the stacking density of ceramsite is less than that of cement clinker, the porosity in the stacked state on the grate bed becomes larger, the penetration ability of the cooling air becomes stronger, the required cooling air pressure becomes smaller, and the power consumption is saved, so the material stacking height (or grate bed height) in the grate cooler is increased, the unit cooling capacity of the grate cooler is greatly improved, the waste heat recovery efficiency is increased, and the cooling power consumption is reduced. The above-mentioned ceramsite roasting kiln is a rotary ceramsite roasting kiln, and the inlet and outlet of the rotary ceramsite roasting kiln are installed at the inlet end of the grate cooler with a slope of 2.5%; a temperature measuring device 3 that moves horizontally along the kiln body is provided on the outer wall of the kiln body; the outlet end of the rotary ceramsite roasting kiln is connected to a sealed door cover 400, and the lower end surface of the door cover is sealed and connected to the inlet of the grate cooler.

[0035] The rotary ceramsite roasting kiln in this embodiment adopts the following structure, specifically including a kiln body 1, and the inner wall of the kiln body is provided with a refractory layer 2 from the kiln head (discharging end) to the kiln tail (feeding end). The kiln body is sequentially provided with a material blocking check zone 101 and a rapid roasting zone 102 from the feeding end to the discharging section, and a material blocking boss 111 is provided in the middle of the material blocking zone. The cross-sectional shape of the material blocking boss is a trapezoidal structure, and the height of the material blocking boss is not more than 1 / 2 of the height of the arch height part to avoid being too high; wherein the material blocking check zone 101 prevents material return and sealing, and at the same time prolongs the residence time of the material in the kiln tail, and the same material per unit time is heated relatively slowly, preventing the ceramsite from directly rushing to the kiln head, thereby meeting the roasting time of the ceramsite blank and ensuring the quality of the ceramsite; a material inlet constriction 103 is provided on the side of the inlet in the material blocking control zone to reduce the breakage of the ceramsite.

[0036] The fast combustion zone is provided with three or more arch height parts 104 with curved surface structures along the circumferential direction of the kiln body. Preferably, the curve change of the arch height part is y=x n Function, where n is any real number, n>0; this embodiment has four; rapid roasting zone, the function of the rapid roasting zone: mainly to realize rapid roasting of ceramsite in the thermoplastic state, rapid heat exchange and ceramicization of the surface of ceramsite. When entering the rapid roasting zone, facing the high temperature brought by the flame of the spray gun, the surface of the ceramsite quickly forms a slightly molten liquid phase, and the gas inside the ceramsite is sealed inside the ceramsite. The gas inside will produce a certain uniform expansion, so that the volume of the ceramsite begins to expand or slightly expand instantly. At this time, after the ceramsite enters the burner and cools, the surface of the ceramsite forms a ceramic state, which is conducive to reducing water absorption and improving surface strength. A homogeneous porous structure is formed inside, which reduces the bulk density of the ceramsite; a discharge constriction 105 is provided in the discharge section of the rapid roasting zone, which has the function of collecting ceramsite.

[0037] Preferably, the outer wall of the kiln body is provided with a temperature measuring device 3 which moves horizontally along the kiln body. Preferably, the temperature measuring device is a CS400 rotary kiln thermal imaging system, which can image each brick in the kiln in real time through continuous infrared monitoring, thereby preventing high costs due to downtime and extending the equipment operation time. The CS400 rotary kiln thermal imaging system is designed for harsh furnace environments and is an integrated solution. The equipment can monitor the rotary kiln and detect abnormal hot spots, helping your team avoid high costs and unplanned downtime due to kiln damage; always monitor the problems of the cylinder, scan the outer wall of the cylinder and provide real-time feedback on the temperature changes of the entire kiln body. If it is higher than the safe temperature, it proves that the refractory material in the kiln body is damaged and needs to be repaired in time. If it is lower, it means under-firing and the roasting temperature needs to be adjusted;

[0038] Preferably, the inlet and outlet constrictions and the arch height are all provided with an inward guide slope 106 to prevent the ceramsite from breaking during transportation and to play a guiding role.

[0039] The present invention adopts the above-mentioned rotary ceramsite roasting kiln to produce ceramsite, and an SNCR high-temperature denitration device is arranged at the center of the feed end of the rotary ceramsite roasting kiln, the outlet temperature of the denitration nozzle of the SNCR high-temperature denitration device is ≥750°C, and the SNCR high-temperature denitration device is arranged in the center of the kiln to penetrate into the inside of the kiln tail, and then the rotary ceramsite roasting kiln is opened for firing, preferably, the rotation speed of the rotary ceramsite roasting kiln is 0.1-5r / min; the roasted ceramsite is retained from the discharge end of the rotary ceramsite roasting kiln and enters a grate cooler after passing through a sealed door cover to cool the ceramsite, thereby completing the roasting and cooling of the ceramsite.

[0040] Example 2, please refer to Figure 1 , Figures 5 to 8 ; A ceramsite roasting and firing system, comprising a ceramsite roasting kiln 100, and also comprising a grate cooler 200 for cooling the ceramsite; the ceramsite roasting kiln mentioned above is a rotary ceramsite roasting kiln, and the inlet and outlet of the rotary ceramsite roasting kiln are installed at the inlet end of the grate cooler with a slope of 2.5%; a temperature measuring device 3 is provided on the outer wall of the kiln body and moves horizontally along the kiln body; the outlet end of the rotary ceramsite roasting kiln is connected to a sealed door cover 400, and the lower end surface of the door cover is sealed and connected to the inlet of the grate cooler.

[0041] The rotary ceramsite roasting kiln in this embodiment adopts the following structure, specifically comprising a kiln body 1

[0042] See also Figures 5 to 8 A segmented roasting rotary kiln comprises a kiln body 1, the inner wall of the kiln body is provided with a refractory layer 2 from the kiln head (discharging end) to the kiln tail (feeding end), the kiln body is provided with a preheating and denitrification zone 121, a shaping and regulating zone 122 and a rapid calcination zone 123 from the feeding end to the discharging section, the cross-sectional area in the kiln body decreases in sequence from the preheating and denitrification zone, the shaping and regulating zone and the rapid calcination zone, a plurality of annular protrusions 124 for prolonging the residence time of the material and regulating the orderly release of the gas-generating substances inside the ceramsite are provided in the shaping and regulating zone along the axial direction of the kiln body, and a receiving groove 125 for filling the active substance is formed between adjacent annular protrusions; the rapid combustion zone is provided with three or more arch height portions 126 with curved surface structures along the circumferential direction of the kiln body, and three are provided in this embodiment. For general solid waste calcination, the refractory material solid waste can be made of any of the following: silica-molybdenum bricks, anti-stripping high-aluminum bricks, mullite refractory materials, magnesia-aluminum spinel refractory materials, etc. For hazardous waste raw materials that are severely corroded by alkali, sulfur, chlorine and other volatile components, silica-molybdenum bricks are generally used to improve thermal shock resistance and wear resistance. For 3D printing integrated molding technology, amorphous refractory materials are used: any of cement-free refractory castables, anti-scaling castables, phosphate refractory castables, alkali-resistant castables and thermal insulation castables.

[0043] The core innovation of the present invention, namely the technical effect of segmented design, is described in detail below:

[0044] Preheating and denitrification zone function: the intelligent in-and-out adjustable SNCR function can be set at the kiln tail according to the denitrification temperature. Because the height of the material carried on the back in this area is relatively small, the breakage rate can be reduced, and the drying area is larger than the structure with all protrusions or all three leaves, which can quickly improve the drying of ceramsite raw balls.

[0045] Function of the shaping and regulating zone: ensure that the material has enough residence time and regulate the orderly release of the gas-generating substances inside the ceramsite, so as to obtain ceramsite with different pore structures. In particular, the groove structure can be pre-added with silica ash or rice husk ash active substances to wrap the surface of the ceramsite, and a layer of active substances can be wrapped around the molten ceramsite. For fired coal gangue ceramsite, sludge ceramsite, etc., they can stay in this area for a sufficient time to volatilize the volatile organic matter, and then burn on the surface of the ceramsite in the thermoplastic state. After the thermoplastic ceramsite is shaped by collision and friction with each other, the surface of the ceramsite becomes tighter and the release of the internal gas is sealed.

[0046] Function of the rapid calcination zone: mainly to achieve rapid calcination, rapid heat exchange and ceramicization of ceramsite in a thermoplastic state. When entering the rapid calcination zone, facing the high temperature brought by the flame of the spray gun, the surface of the ceramsite quickly forms a slightly molten liquid phase, sealing the gas inside the ceramsite inside the ceramsite. The gas inside will produce a certain uniform expansion, so that the volume of the ceramsite begins to expand instantly or slightly. At this time, after the ceramsite enters the burner and cools down, the surface of the ceramsite forms a ceramic state, which is conducive to reducing water absorption and improving surface strength. A homogeneous porous structure is formed inside, reducing the bulk density of the ceramsite.

[0047] When the above structure is actually produced, the following technical scheme can be adopted: the thickness of the steel plate of the ceramsite kiln is 25-40mm; the thickness of the refractory material of the ceramsite kiln cylinder from the kiln tail to the kiln head is 150-200mm, and the aspect ratio is 5-10.

[0048] The masonry method of refractory materials in the kiln: the preheating and denitrification zone adopts ordinary masonry method, and the shaping and control zone is based on the preheating and denitrification zone, using refractory bricks and kiln shell to build together along the axial section using high-temperature resistant bonding materials and rake nails to form annular protrusions. The distance between each two adjacent annular protrusions is 2-4 times the height of the annular protrusions, the height of each annular protrusion is 0.05-0.1 times the radius of the kiln, and the width of the root of the annular protrusion is 1-2.5 times the height. From the feeding direction to the discharging direction, the height of the annular protrusions is the same or gradually increases linearly along the movement direction of the expanded clay. The rapid calcination zone uses refractory bricks and the refractory materials of the shell to be bonded together with a binder.

[0049] These annular protrusions can be assembled together before leaving the factory and baked at high temperature to make the bonding joints firm. In addition, these special-shaped structures can be formed by integrated 3D printing and high-temperature drying before leaving the factory or after on-site installation according to 3D printing technology. Of course, they can also be 3D printed in sections according to different functional areas of the kiln and dried at high temperature to improve construction efficiency and quality and save labor costs.

[0050] The material of the three-stage refractory material is set accordingly according to the nature of the material, whether it is solid waste or hazardous waste. For corrosive materials or materials with a large amount of liquid phase, it can avoid the crust blockage that may occur during the firing of the existing three-leaf structure formed by splicing, even the shedding of the kiln skin, and the damage of the three-leaf structure caused by snowballing, and even the cracking of the kiln body. The refractory material formed in one piece by 3D printing technology in the arch height part has high molding quality, no gaps, consistent thermal expansion performance of the material, and good refractory effect.

[0051] More preferably, the curve of the arch height portion changes to y=x n function of , where n is any real number, n>0.

[0052] Further preferably, the cross-sectional area of ​​the shaping and regulating zone is 70% to 80% of the cross-sectional area of ​​the preheating and denitrification zone; and the cross-sectional area of ​​the rapid calcination zone is 40% to 50% of the cross-sectional area of ​​the preheating and denitrification zone.

[0053] Further preferably, the length of the kiln body is L; the length of the preheating and denitrification zone is less than or equal to 0.3L, the length of the shaping and control zone is 0.25-0.4L; and the length of the rapid calcination zone is 0.3-0.45L.

[0054] Further preferably, the distance between each two adjacent annular protrusions is 2-4 times the height of the annular protrusions, the height of each annular protrusion is 0.05-0.1 times the radius of the kiln, the width of the root of the annular protrusion is 1-2.5 times the height, and the height of the annular protrusions is the same from the feeding direction to the discharging direction or gradually increases linearly along the movement direction of the expanded clay.

[0055] Further preferably, the preheating and denitrification zone, the shaping and regulating zone, and the rapid calcination zone of the kiln body are an integrated structure.

[0056] Preferably, the preheating and denitrification zone, shaping and regulating zone, and rapid calcination zone of the kiln body are separate structures. In this way, each functional area can achieve the best effect on the calcination of ceramsite. Each section has a driving device, and the speed can be changed according to the characteristics of the material firing to adapt to different working conditions.

[0057] The ceramsite kiln of the present invention is designed with three different functional areas. Firstly, the purpose is to solve the problem that the ceramsite raw material balls have a long residence time in the kiln and a high breakage rate due to the convex or concave structures along the axial direction of the kiln; secondly, the purpose is to solve the problem that when the kiln is a trilobate structure, the filling rate in the front section is high, and the ceramsite raw material balls at the kiln tail are lifted to nearly 90 degrees and fall down to cause more breakage and impact breakage; thirdly, the purpose is to solve the problem that when the kiln is a smooth straight tube kiln without any structure, the filling rate is low, and the length of the kiln needs to be lengthened to burn qualified ceramsite, and the lengthening of the kiln makes the temperature at the kiln tail lower, which is not conducive to the denitration efficiency of the high-temperature SNCR at 850°C, especially the too low denitration temperature will make the subsequent denitration use the SCR denitration technology with higher investment cost, and the investment and the land occupation will increase after the kiln is lengthened.

[0058] The present invention also discloses a method for producing ceramsite, which comprises adopting the integrated segmented roasting rotary kiln to roast ceramsite, arranging an SNCR high-temperature denitration device at the center of the feed end of the rotary kiln, the outlet temperature of the denitration nozzle of the SNCR high-temperature denitration device being ≥750°C, and arranging the SNCR high-temperature denitration device at the center of the kiln to penetrate into the kiln tail by 1-3 kiln tail inner diameters of the rotary kiln; adding silica ash or rice husk ash active substances to wrap the surface of the ceramsite between the annular protrusions in the shaping control zone of the rotary kiln, wherein the presence of the substances can also reduce the impact between particles and reduce the breakage rate; and then starting the rotary kiln to roast the ceramsite.

[0059] The present invention also discloses a method for producing ceramsite, which comprises adopting a segmented roasting rotary kiln to burn ceramsite, wherein the preheating denitrification zone, the shaping and regulating zone and the rapid calcining zone of the rotary kiln are split, and an SNCR high-temperature denitration device is arranged at the center of the feeding end of the rotary kiln, the outlet temperature of the denitration nozzle of the SNCR high-temperature denitration device is ≥750°C, and the SNCR high-temperature denitration device is arranged at the center of the kiln to penetrate into the kiln tail by 1-3 times of the inner diameter of the rotary kiln at the kiln tail; silicon ash or rice husk ash active material for coating the surface of ceramsite is added between the annular protrusions of the shaping and regulating zone of the rotary kiln; and then the rotary kiln is started,

[0060] The preheating and denitrification zone, shaping and control zone, and rapid calcination zone of the rotary kiln maintain different rotation speeds respectively;

[0061] Alternatively, when the organic carbon content in the ceramsite is ≤2%, the preheating and denitrification zone, shaping and regulating zone and rapid calcination zone of the rotary kiln maintain the same rotation speed; when the organic carbon content in the ceramsite is >2%, the shaping and regulating zone and the rapid calcination zone maintain the same rotation speed and are greater than or equal to the rotation speed of the preheating and denitrification zone of the rotary kiln. In this way, each functional area can achieve the best effect on the calcination of ceramsite.

[0062] Preferably, the rotation speed of the preheating and denitrification zone is 1.5-3r / min, the rotation speed of the shaping and control zone is 2.0-3r / min, and the rotation speed of the rapid calcination zone is 2.5-4r / min.

[0063] In summary, by optimizing the internal structure design of the rotary expanded clay roasting kiln, efficient and rapid expanded clay production is achieved, the productivity of expanded clay is improved, the cooling capacity of the grate cooler is greatly improved, the waste heat recovery efficiency is increased, and the cooling power consumption is reduced.

[0064] The above description is only a preferred embodiment of the present invention and is not intended to limit the present invention. Any modifications, equivalent substitutions and improvements made within the spirit and principles of the present invention should be included in the protection scope of the present invention.

Claims

1. A ceramsite roasting and firing system, comprising a ceramsite roasting kiln, characterized in that: It also includes a grate cooler for cooling ceramsite; wherein the ceramsite roasting kiln is a rotary ceramsite roasting kiln, the inlet and outlet of the rotary ceramsite roasting kiln are installed at the inlet end of the grate cooler at a slope of 2.5%; a temperature measuring device that moves horizontally along the kiln body is provided on the outer wall of the kiln body; the outlet end of the rotary ceramsite roasting kiln is connected to a sealed door cover, and the lower end face of the door cover is sealed and connected to the inlet of the grate cooler; the rotary ceramsite roasting kiln includes a kiln body, the inner wall of the kiln body is provided with a refractory layer from the kiln head to the kiln tail, and the kiln body From the feeding end to the discharging section, there are the preheating and denitrification zone, the shaping and control zone and the rapid calcination zone in sequence. The cross-sectional area in the kiln body decreases in sequence from the preheating and denitrification zone, the shaping and control zone and the rapid calcination zone. In the shaping and control zone, there are several annular protrusions along the axial direction of the kiln body for extending the residence time of the material and regulating the orderly release of the gas-generating substances inside the ceramsite. A receiving groove for filling the active substance is formed between adjacent annular protrusions; the rapid combustion zone is provided with three or more arch height parts with curved surface structures along the circumferential direction of the kiln body.

2. The ceramsite roasting and firing system according to claim 1, characterized in that: The cross-sectional area of ​​the shaping and regulating zone is 70% to 80% of the cross-sectional area of ​​the preheating and denitrification zone; the cross-sectional area of ​​the rapid calcination zone is 50% to 60% of the cross-sectional area of ​​the preheating and denitrification zone.

3. The ceramsite roasting and firing system according to claim 1, characterized in that: The length of the kiln body is L; the length of the preheating and denitrification zone is less than or equal to 0.3L; the length of the shaping and regulating zone is 0.25~0.4L; and the length of the rapid calcination zone is 0.3~0.45L.

4. The ceramsite roasting and firing system according to claim 1, characterized in that: The distance between each two adjacent annular protrusions is 2-4 times the height of the annular protrusions, the height of each annular protrusion is 0.05-0.1 times the kiln radius, and the width of the root of the annular protrusion is 1-2.5 times the height.

5. The ceramsite roasting and firing system according to claim 1, characterized in that: The height of the annular protrusion is the same from the feeding direction to the discharging direction or increases linearly along the moving direction of the ceramsite.

6. The ceramsite roasting and firing system according to claim 1, characterized in that: The curve change of the arch height is y=x n function of , where n is any real number, n>0.

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