A method and system for layered cloth sintering and cooling

Abstract

A method for layered sintering and cooling includes the following steps: 1) alternately laying sintering raw materials and spacers on a sintering trolley to obtain a mixed sintering material layer with multiple sintering material unit layers separated from top to bottom by at least one layer of spacers; starting the sintering machine to sinter the mixed sintering material layer to obtain at least two sintered ore unit layers with different temperatures; 2) according to the different temperatures of each sintered ore unit layer, independently crushing and cooling each sintered ore unit layer to obtain the finished sintered ore. This invention provides a method for layered sintering and cooling, which sets up multiple sintering raw material unit layers for sintering and sets up spacers to cool the sintered ore at different temperatures after sintering, improving cooling efficiency and sintered ore heat recovery rate, while reducing the workload of the annular cooler and saving the initial investment in the annular cooler.

Description

Technical Field

[0001] This invention relates to a sintering and cooling method and system, specifically to a layered material sintering and cooling method and system, belonging to the field of iron ore sintering technology. Background Technology

[0002] Sintering is a common method for iron ore agglomeration in the steelmaking process. Currently, China's annual sinter production exceeds 1 billion tons. The main fuel used in sintering is coke powder. Based on the current energy consumption of 40-50 kgce per ton of sinter, the sintering industry emits over 100 million tons of CO2 annually, making it a significant source of CO2 emissions for the steel industry and even the entire country. Under the national dual-carbon strategy, carbon emission reduction in the sintering process is particularly important. The current mainstream sintering process uses draft sintering, with key equipment including belt sintering machines, ignition and holding furnaces, material feeders, and annular coolers. Belt sintering machines, due to their high single-strength output and high degree of mechanization and automation, have become the absolute mainstream in global sintering production.

[0003] Domestic and foreign researchers have conducted a lot of research and attempts on energy saving and low carbon in the sintering process. At present, the most advanced level of energy consumption in the sintering process has reached below 40 kgce / ts, but the energy consumption of most sintering machines is still generally between 40 and 50 kgce / ts, and there is still room for energy consumption in the sintering process to be reduced.

[0004] The sintering raw materials mainly consist of iron ore, flux, and fuel. The sintering fuel is primarily fossil fuel coke powder, accounting for approximately 3-5% of the raw materials. After thorough mixing and granulation, the various components of the sintering raw materials are evenly spread onto the sintering trolley by a distributor. Figure 3 The trolley shown moves at a constant speed from left to right. When the trolley enters the ignition and holding furnace, combustion gas and air are introduced through the ignition burners for ignition. The coke powder on the surface of the sintering raw material is ignited. Subsequently, under the negative pressure of the exhaust fan under the trolley, air above the trolley is continuously drawn into the material layer, and the combustion zone in the material layer is transferred from top to bottom, completing the entire sintering process. The high-temperature flue gas is drawn by the main exhaust fan into the large flue below the trolley, and after waste heat utilization and desulfurization and denitrification, it is discharged into the atmosphere. The average temperature of the sintered hot ore when unloaded from the trolley reaches about 750℃, and it is sent to the annular cooler to be cooled to below 150℃. The ring cooler uses a forced-air method to cool the sintered ore, and the high-temperature waste gas generated is used for waste heat utilization. The temperature of the cooling waste gas in the first 40% of the ring cooler reaches 250-500℃, which can generally be used for steam power generation. The cooling air temperature in the latter half is lower, and it is generally used as the combustion air for the sintering ignition furnace or for hot air sintering.

[0005] Analysis of existing cross-sectional images of the sintering machine tail section shows that the sintering process is basically complete when the sinter reaches the tail section. Due to the heat storage effect caused by the air intake at the bottom of the sintering machine, only the sinter at the bottom of the sintering machine remains at a high temperature and red-hot state, while the upper sintering machine is cooled by the intake air, and its actual temperature is already lower. Figure 4 The diagram shown is a schematic AA of the cross-section of the tail carriage of the sintering machine. The sinter exhibits obvious stratification at the temperature of the carriage cross-section. Figure 2 Middle III is the red material zone (i.e., the high-temperature zone), concentrated in the lower 30% of the material layer, with a temperature of 700-1200℃ and an average temperature of 1000-1050℃; II is the medium-temperature ore zone, concentrated in the upper 40% of the material layer, with a relatively wide temperature distribution, ranging from 150-700℃ and an average temperature of 350-400℃; Surface I is the uppermost layer of the material layer that is in contact with air, and is basically close to room temperature, with a temperature range of 50-150℃.

[0006] The current feeding and cooling method involves mixing and crushing 70% of the medium- and low-temperature black material from the upper and middle sections with 30% of the high-temperature dried material from the lower section before feeding it into the ring cooler. This reduces the overall temperature of the sinter, increases the workload of the ring cooler, and reduces the waste heat quality and utilization efficiency of the sinter. Summary of the Invention

[0007] To address the problems of low waste heat quality and utilization efficiency of sintered ore and high workload of the annular cooler in existing technologies, this invention proposes a layered feeding sintering and cooling method and system. The sintering raw material is divided into at least two sintering raw material unit layers from top to bottom, with a spacer layer between adjacent sintering raw material unit layers. After sintering, different cooling methods are used for different sintered ore thermal qualities, cooling the upper low-temperature sintered ore and the lower high-temperature sintered ore separately, thereby improving cooling efficiency and sintered ore heat recovery rate.

[0008] According to a first embodiment of the present invention, a method for sintering and cooling layered fabric is provided.

[0009] A method for sintering and cooling layered fabric, the method comprising the following steps:

[0010] 1) The sintering raw materials and spacers are alternately laid on the sintering trolley to obtain a mixed sintering material layer with multiple sintering material unit layer structures formed by separating the sintering raw materials from top to bottom by at least one layer of spacers; the sintering machine is started to sinter the mixed sintering material layer to obtain at least two sintering ore unit layers with different temperatures.

[0011] 2) Based on the different temperatures of each sinter unit layer, each sinter unit layer is independently crushed and cooled to obtain the finished sinter.

[0012] Preferably, in step 1), the number of spacer layers in the mixed sintering material layer is 1 to 5, preferably 2 to 3; each spacer layer has a sintered raw material unit layer on its upper and lower sides. Preferably, the thickness of each spacer layer is the same or different. The thickness of each sintered raw material unit layer is the same or different.

[0013] Preferably, the spacer material in the spacer layer is a mixture of any one or more of coal gangue, blast furnace slag, steel slag, limestone, and lump ore.

[0014] Preferably, the thickness of the spacer layer is 1 to 10 cm, and more preferably 2 to 8 cm.

[0015] Preferably, the spacer material has a particle size of 5-10 mm, and more preferably 6-9 mm.

[0016] Preferably, the spacer layer is any one of the following: a 3-5 cm thick coal gangue layer, a 5-8 cm thick blast furnace slag layer, a 5-8 cm thick steel slag layer, a 1-3 cm thick limestone layer, and a 5-8 cm thick lump ore layer.

[0017] Preferably, the spacer layer also contains fuel; preferably, the fuel is coke; preferably, the amount of fuel added to the spacer layer is controlled so that the total carbon content in the coal gangue layer is 20% to 30%, the total carbon content in the blast furnace slag layer, steel slag layer, and lump ore layer is 3% to 5%, and the total carbon content in the limestone layer is 0.5% to 2%; preferably, the carbon content in the lower spacer layer is less than the carbon content in the upper spacer layer.

[0018] Preferably, the step of cooling each sintered ore unit layer independently involves sending each sintered ore unit layer to a different annular cooler for cooling according to its temperature, and utilizing the waste heat of different qualities collected by the different annular coolers separately.

[0019] Preferably, based on the temperature of each sintered ore unit layer obtained after sintering, the different sintered ore unit layers are divided into a medium-temperature layer and a high-temperature layer, and optionally include or exclude a low-temperature layer; the sintered ore in the low-temperature layer is transported to the sintered finished product warehouse, the sintered ore in the medium-temperature layer is sent to a low-temperature ring cooler for cooling, and the sintered ore in the high-temperature layer is sent to a high-temperature ring cooler for cooling.

[0020] Preferably, the temperature of the sinter in the low-temperature layer is 50–200°C; the temperature of the sinter in the medium-temperature layer is 150–800°C; and the temperature of the sinter in the high-temperature layer is 700–1200°C.

[0021] Preferably, the separate utilization of waste heat of different qualities collected by different annular coolers specifically involves: the low-temperature annular cooler obtaining low-temperature cooling waste gas; the front section of the high-temperature annular cooler obtaining high-temperature cooling waste gas, the middle section of the high-temperature annular cooler obtaining medium-temperature cooling waste gas, and the rear section of the high-temperature annular cooler obtaining low-temperature cooling waste gas; the obtained low-temperature cooling waste gas being used for sintering ignition or hot air sintering, and the high-temperature cooling waste gas being used for power generation.

[0022] Preferably, in the mixed sintering material layer, there are two spacer layers, which divide the sintering material from top to bottom into an upper unit layer, a middle unit layer, and a lower unit layer. The thickness of the upper unit layer is L1, %; the thickness of the middle unit layer is L2, %; and the thickness of the lower unit layer is L3, %; where L1, L2, and L3 are the percentages of each layer's thickness relative to the total thickness of the material layers excluding the thickness of the spacer layers. The percentage of each layer relative to the total thickness of the material layers is determined by the following formula:

[0023]

[0024] L2 = 1 - L1 - L3 ... (Equation 3)

[0025] In the formula, r is the average particle size of the sintering raw material, mm; M is the moisture content of the sintering raw material, %; C is the carbon content of the sintering raw material, %; L is the total thickness of the material layer, cm; d is the total thickness of the two separating layers, cm; α, β, γ, and δ are adjustment coefficients, with α ranging from 0.2 to 0.8, β ranging from 0.2 to 0.8, γ ranging from 1 to 3, and δ ranging from 2 to 5.

[0026] According to a second embodiment of the present invention, a system for sintering and cooling layered fabric is provided.

[0027] A layered sintering and cooling system includes a sintering machine, a sintering trolley, a material feeding device, an ignition device, a flue gas treatment device, a sinter separation device, and an annular cooler. The sintering trolley is mounted on the sintering machine, and the material feeding device and ignition device are both positioned above the sintering trolley. A large flue is located below the sintering machine, and the flue gas treatment device is connected to the large flue. Based on the movement direction of the sintering trolley, the material feeding device is positioned upstream of the ignition device. The material outlet of the sintering machine is connected to the material inlet of the sinter separation device, and the material outlet of the sinter separation device is connected to the material inlet of the annular cooler. At least two layers of sintering raw material unit layers are laid on the sintering machine, with a separating layer between adjacent sintering raw material unit layers. The system includes 2 to 6 annular coolers, and the sinter separation device has the same number of material outlets as the annular coolers. Preferably, the spacer material in the spacer layer is any one or more of coal gangue, blast furnace slag, steel slag, limestone, and lump ore. Preferably, the sintering machine is laid with three layers of sintering raw material unit layers and two layers of spacer material layers, with the sintering raw material unit layers and spacer material layers laid alternately. The system also includes a sintered finished product bin. The annular cooler includes a high-temperature annular cooler and a low-temperature annular cooler. The sintered ore separation device has a high-temperature material outlet, a medium-temperature material outlet, and a low-temperature material outlet. The low-temperature material outlet is connected to the sintered finished product bin, the medium-temperature material outlet is connected to the low-temperature annular cooler, and the high-temperature material outlet is connected to the high-temperature annular cooler.

[0028] In this invention, multiple sintering raw material unit layers are arranged from top to bottom in the sintering trolley, with spacer layers between adjacent sintering raw material unit layers to form a mixed sintering material layer. After sintering, multiple sintered ore unit layers with different temperatures and no agglomeration are obtained. The lower sintered ore unit layers have higher temperatures and relatively higher waste heat quality, while the upper sintered ore unit layers have lower temperatures and relatively lower waste heat quality. The multiple sintered ore unit layers are cooled separately. Cooling the high-temperature sintered ore unit layers yields high-quality waste heat, while cooling the low-temperature sintered ore unit layers yields low-quality waste heat. Different cooling methods are used for different sintered ore heat qualities, improving cooling efficiency and sintered ore heat recovery rate, while reducing the workload of the annular cooler and saving on the initial investment in the annular cooler.

[0029] In this invention, to achieve layered and graded cooling of sintered ore, it is necessary to separate the sintered ore according to different temperature levels before cooling. Since sintering is a process in which iron ore, under the combined reaction of coke and flux, produces a liquid phase and agglomerates into a block, the originally bulk sintering raw materials become a single, continuous block after sintering. Conventional cooling requires the sintered ore to be crushed as a whole; therefore, the effective separation of sintering raw materials during the sintering process is the key and challenge of this invention. To solve the aforementioned problems, the spacer layer must meet the following requirements: 1. It must be able to transmit the combustion zone. Since sintering relies on bottom suction to form a combustion zone, high temperatures are generated along the path of the combustion zone, causing the sintered ore to melt and sinter. If the spacer layer blocks the transmission of the combustion zone, it will cause sintering to extinguish, and sintering below the spacer layer will not be completed. 2. It must be able to prevent agglomeration. Metallic minerals form a low-temperature eutectic under the action of flux, which then agglomerates upon cooling, thus completing sintering. However, the spacer layer itself cannot participate in the caking reaction, thus forming integral sinter unit layers above and below the spacer layer, facilitating subsequent bulk separation. 3. It must have a certain degree of permeability. Air must be able to efficiently penetrate the spacer layer to provide oxygen to the lower sinter layers. 4. It must have a certain degree of mechanical strength. Due to the relatively high density and weight of sinter, the spacer layer, located below the sinter, is subjected to pressure from the sinter above and must be able to withstand the pressure from the sinter to prevent collapse. 5. It should minimize the addition of unnecessary materials to the steelmaking process. Because the spacer layer inevitably enters the blast furnace along with the sinter, too much useless material will inevitably increase the blast furnace's smelting energy consumption. 6. It should have low cost and a wide range of material sources.

[0030] In this invention, based on the requirements for the spacer layer, several spacer layer materials are proposed, and specific requirements for the thickness of the spacer layer corresponding to each material are proposed based on the characteristics of the spacer layer materials: 1. Coal gangue. Coal gangue is a solid waste generated during coal mining and coal preparation. Coal gangue contains a certain amount of carbon, which can effectively transfer the sintering combustion zone. As a spacer material, the carbon content of coal gangue should not be less than 20%, the particle size of coal gangue should be 5-10mm, and the thickness of the material in the layer should be 3-5cm. Too low a carbon content will lead to failure of sintering ignition, too small a particle size will affect the sintering permeability, and too large a particle size will lead to too large a void in the spacer layer, allowing the sintered material to penetrate into the voids and failing to effectively isolate adjacent sintering raw material unit layers. 2. Blast furnace slag and steel slag. Blast furnace slag and steel slag come from the steelmaking process itself, and their output is large and the supply is stable, without increasing additional material procurement costs. Steel slag contains 10%–20% iron. After sintering and returning it to the blast furnace, some iron can be recovered. The blast furnace slag and steel slag used as the interlayer material have a particle size of 5–10 mm and are laid 5–8 cm thick in the interlayer. Since the steel slag still contains a certain amount of iron, to prevent this iron from melting and sintering, which would cause difficulties in subsequent separation, the thickness of the interlayer material needs to be slightly thicker than that of coal gangue. Due to the relatively thick interlayer material, to prevent the combustion zone from failing to penetrate the interlayer, an additional 3%–5% coke needs to be added to the lump ore as an ignition medium for combustion. 3. Limestone. The main component of limestone is calcium carbonate. Under the sintering combustion zone temperature (1100–1300℃), it decomposes to produce lime (CaO) and carbon dioxide. Carbon dioxide enters the main flue with the sintering flue gas, while lime enters the blast furnace along with the sintered ore, serving as a slagging agent for the blast furnace. Limestone is an ideal material separating medium because it does not add unnecessary materials to the steelmaking process, does not increase blast furnace energy consumption, and is widely available. When using limestone as a separating medium, the particle size should be 5-10mm, and the thickness in the material layer should be 1-3cm. Since limestone does not contain carbon and its decomposition is endothermic, excessive thickness may cause the sintering combustion zone to extinguish; therefore, the thickness must be controlled within a reasonable range. 4. Lump Ore. Lump ore is one of the three main raw materials for blast furnace iron (sinter, pellets, and lump ore). Using lump ore as a separating medium does not require additional material flow to the steelmaking process and does not increase additional material procurement costs. The particle size of the lump ore used as a separating medium should be 5-10mm, and the thickness in the material layer should be 5-8cm. When using lump ore as a separating medium, due to the relatively thick material layer, to prevent the combustion zone from failing to penetrate the separating zone, 3%-5% coke needs to be added to the lump ore as an ignition medium to facilitate combustion. Based on the properties of each interlayer material, this invention specifies the laying thickness of each material and also limits the carbon content in the interlayer to achieve the best interlayer effect.

[0031] In this invention, when the number of spacer layers in the mixed sintering material layer is two, the material layer is divided into an upper unit layer, a middle unit layer, and a lower unit layer of sintering material. The thickness of each layer is affected by the characteristics of the sintering material. When the particle size and moisture content of the sintering material are larger, the air permeability is better, the upper layer is cooled better by air, and the heat is carried away more smoothly by the flue gas, resulting in a larger L1 and a smaller L3. When the carbon content in the sintering material layer is higher, the sintering heat storage effect is more obvious, resulting in a larger L3. The thickness of each material layer is determined by the following formula:

[0032]

[0033] L2 = 1 - L1 - L3

[0034] In the above formula, the thicknesses of the upper, middle, and lower layers are L1, L2, and L3, respectively, in percentage (%), which is the percentage of the total thickness of each layer excluding the thickness of the separator layer; r is the average particle size of the sintering raw material, mm; M is the moisture content of the sintering raw material, %; C is the carbon content of the sintering raw material, %; L is the total thickness of the material layer, cm; d is the total thickness of the two separator layers, cm; α, β, γ, and δ are adjustment coefficients, with α ranging from 0.2 to 0.8, β ranging from 0.2 to 0.8, γ ranging from 1 to 3, and δ ranging from 2 to 5.

[0035] The following are several sets of values ​​calculated based on the above formula. In the table, the total thickness D of the material layer is taken as 100cm, and the total thickness of the separating material layer is taken as 8cm.

[0036] r / mm C M α β γ δ <![CDATA[L1 / %]]> <![CDATA[L2 / %]]> <![CDATA[L3 / %]]> 5 3.5％ 8％ 0.4 0.3 1.8 2.8 21.5 34.3 44.2 5 4.5 8％ 0.4 0.3 1.8 2.8 19.4 30.2 50.4 10 3.5 8％ 0.4 0.3 1.8 2.8 26.5 33.2 40.3 5 3.5 12％ 0.4 0.3 1.8 2.8 17.4 48.5 34.0

[0037] In this invention, the actual number of sintering raw material unit layers is determined by comprehensively considering factors such as the thickness of the material layer and the quality of the sintered ore during the production process. When there are 3 sintering raw material unit layers and 2 spacer layers, they are labeled A, B, C, D, and E from top to bottom, where A, C, and E are sintering raw material unit layers, and B and D are spacer layers. After sintering, the sintered ore in layer A is low-temperature sintered ore (50–150°C), the sintered ore in layer C is medium-temperature sintered ore (150–700°C), and the sintered ore in layer E is high-temperature sintered ore (700–1200°C). After the surface sintered ore is ignited in the furnace, the sintering material begins to sinter from top to bottom, with the combustion zone penetrating the spacer zone and continuing to sinter downwards. Before the sintered ore is unloaded from the trolley, the three layers of sintered ore (A, C, and E) are separated by a dedicated separation device and crushed separately. After the sinter is separated and crushed, the A-layer sinter, being close to the sintering surface, has a lower temperature, only 50-150℃, and its thickness accounts for 20%-30% of the sintering raw material unit layer. This portion of the sinter is close to room temperature, has low waste heat utilization value, and meets the temperature conditions for conventional belt conveyor transport; therefore, it can be directly transported to the sintered finished product silo via conventional conveyor belt for later use. The C-layer sinter is a medium-temperature sinter with a wide temperature distribution range, reaching 150-700℃, with an average temperature of 350-400℃. This portion of the sinter is separately cooled in a low-temperature annular cooler to below 150℃ before being transported to the sintered finished product silo via conveyor belt. The cooling exhaust gas temperature is approximately 200-300℃, which can be used for sintering ignition or hot air sintering. The E-layer sinter is a high-temperature sinter with a temperature of 700–1200℃ and an average temperature of 1000–1050℃. It has a high quality of waste heat utilization. After crushing, this part of the sinter is separately cooled by a high-temperature annular cooler. The first 30% of the annular cooler area can generate high-temperature steam above 600℃ for high-parameter power generation, and its heat recovery efficiency is higher than that of traditional technology. The middle 40% of the annular cooler area can generate steam of 400–600℃ for conventional power generation. The last 30% of the annular cooler still generates cooling waste gas of 200–300℃, which is used for sintering ignition or hot air sintering.

[0038] In this invention, since the second spacer layer is at the bottom, sintering has a heat storage effect, so the amount of carbon required for the lower layer can be less, and the amount of carbon in the second spacer layer is less than that in the first spacer layer.

[0039] In this invention, experiments show that using perforated physical partitions to replace the spacer layers is completely infeasible. Sintering is a top-down exhaust process requiring heat and mass transfer downwards. Even with perforated partitions, while hot air and flue gas can pass through the small holes, this is far from sufficient to meet the sintering needs of the lower layers. Therefore, the only advantage of using partitions is good separation, making it easy to separate the sintered layers later. However, the sintered material below the partitions will almost certainly fail to sinter, the combustion zone cannot move downwards, and the middle and lower layers are practically unsintered, severely impacting the main sintering process. Furthermore, the sintering combustion zone temperature is 1200–1400℃, and prolonged exposure to such high temperatures, coupled with the pressure of hundreds of tons of sintered raw material, would generally cause the partitions, regardless of material, to collapse. Therefore, placing partitions within the raw material is practically impossible. The finished sintered ore and high- or low-temperature exhaust gases mentioned later are essentially nonexistent.

[0040] In this invention, it should be noted that if the sintering raw material unit layer is further divided into more detailed layers, the control of heating and cooling of the material layer will be more precise if there are more layers. However, too many layers will also increase the difficulty and cost of material distribution. Therefore, in the actual production process, the number of layers needs to be comprehensively considered based on factors such as the thickness of the material layer, the quality of the sintered ore, and the characteristics of the sintering raw material.

[0041] In this invention, all formulas are obtained by the inventors based on experimental and engineering applications. All calculations are calculated by substituting the converted values ​​into the formulas according to the prescribed units. (After converting the units of each parameter, only the values ​​are substituted into the formulas for calculation, not the units. The units are only used to adjust the size of the values.)

[0042] Compared with the prior art, the present invention has the following beneficial effects:

[0043] 1. The present invention provides a method and system for layered material sintering and cooling, which sets up multiple sintering raw material unit layers for sintering and sets up spacer material layers to cool sintered ore at different temperatures after sintering, thereby improving cooling efficiency and sintered ore heat recovery rate, while reducing the workload of the ring cooler and saving the initial investment of the ring cooler.

[0044] 2. The present invention provides a method and system for layered material sintering and cooling. Based on the performance requirements of the spacer layer, several spacer materials are proposed, and the laying thickness of each material is specifically limited according to the properties of different materials. In addition, parameters such as carbon content in the spacer layer are specifically limited, so as to achieve the best material separation effect without affecting sintering. Attached Figure Description

[0045] Figure 1This is a schematic diagram of a layered fabric sintering and cooling system provided by the present invention.

[0046] Figure 2 This is a cross-sectional view of the sintered ore at point BB.

[0047] Figure 3 This is a schematic diagram of the structure of a sintering system in the prior art.

[0048] Figure 4 This is a cross-sectional view of the sintered ore at point AA.

[0049] Attached figures: 1: Sintering machine; 2: Sintering trolley; 3: Material feeding device; 4: Ignition device; 5: Flue gas treatment device; 6: Sintered ore separation device; 7: Circular cooler; 701: High-temperature circular cooler; 702: Low-temperature circular cooler; 8: Main flue; 9: Sintered finished product warehouse. Detailed Implementation

[0050] The technical solution of the present invention will be illustrated below with examples. The scope of protection sought by the present invention includes, but is not limited to, the following embodiments.

[0051] According to a first embodiment of the present invention, a method for sintering and cooling layered fabric is provided.

[0052] A method for sintering and cooling layered fabric, the method comprising the following steps:

[0053] 1) The sintering raw materials and spacers are alternately laid on the sintering trolley to obtain a mixed sintering material layer with multiple sintering material unit layer structures formed by separating the sintering raw materials from top to bottom by at least one layer of spacers; the sintering machine is started to sinter the mixed sintering material layer to obtain at least two sintering ore unit layers with different temperatures.

[0054] 2) Based on the different temperatures of each sinter unit layer, each sinter unit layer is independently crushed and cooled to obtain the finished sinter.

[0055] Preferably, in step 1), the number of spacer layers in the mixed sintering material layer is 1 to 5, preferably 2 to 3; each spacer layer has a sintered raw material unit layer on its upper and lower sides. Preferably, the thickness of each spacer layer is the same or different. The thickness of each sintered raw material unit layer is the same or different.

[0056] Preferably, in the mixed sintering material layer, there are two spacer layers, which separate the sintering raw material from top to bottom into an upper unit layer, a middle unit layer, and a lower unit layer. The upper unit layer accounts for 25-35% of the total sintering raw material, the middle unit layer accounts for 30-50% of the total sintering raw material, and the lower unit layer accounts for 25-35% of the total sintering raw material.

[0057] Preferably, the spacer material in the spacer layer is a mixture of any one or more of coal gangue, blast furnace slag, steel slag, limestone, and lump ore.

[0058] Preferably, the thickness of the spacer layer is 1 to 10 cm, and more preferably 2 to 8 cm.

[0059] Preferably, the spacer material has a particle size of 5-10 mm, and more preferably 6-9 mm.

[0060] Preferably, the spacer layer is any one of the following: a 3-5 cm thick coal gangue layer, a 5-8 cm thick blast furnace slag layer, a 5-8 cm thick steel slag layer, a 1-3 cm thick limestone layer, and a 5-8 cm thick lump ore layer.

[0061] Preferably, the spacer layer also contains fuel; preferably, the fuel is coke; preferably, the amount of fuel added to the spacer layer is controlled so that the total carbon content in the coal gangue layer is 20% to 30%, the total carbon content in the blast furnace slag layer, steel slag layer, and lump ore layer is 3% to 5%, and the total carbon content in the limestone layer is 0.5% to 2%; preferably, the carbon content in the lower spacer layer is less than the carbon content in the upper spacer layer.

[0062] Preferably, the step of cooling each sintered ore unit layer independently involves sending each sintered ore unit layer to a different annular cooler for cooling according to its temperature, and utilizing the waste heat of different qualities collected by the different annular coolers separately.

[0063] Preferably, based on the temperature of each sintered ore unit layer obtained after sintering, the different sintered ore unit layers are divided into a medium-temperature layer and a high-temperature layer, and optionally include or exclude a low-temperature layer; the sintered ore in the low-temperature layer is transported to the sintered finished product warehouse, the sintered ore in the medium-temperature layer is sent to a low-temperature ring cooler for cooling, and the sintered ore in the high-temperature layer is sent to a high-temperature ring cooler for cooling.

[0064] Preferably, the temperature of the sinter in the low-temperature layer is 50–200°C; the temperature of the sinter in the medium-temperature layer is 150–800°C; and the temperature of the sinter in the high-temperature layer is 700–1200°C.

[0065] Preferably, the separate utilization of waste heat of different qualities collected by different annular coolers specifically involves: the low-temperature annular cooler obtaining low-temperature cooling waste gas; the front section of the high-temperature annular cooler obtaining high-temperature cooling waste gas, the middle section of the high-temperature annular cooler obtaining medium-temperature cooling waste gas, and the rear section of the high-temperature annular cooler obtaining low-temperature cooling waste gas; the obtained low-temperature cooling waste gas being used for sintering ignition or hot air sintering, and the high-temperature cooling waste gas being used for power generation.

[0066] Preferably, in the mixed sintering material layer, there are two spacer layers, which divide the sintering material from top to bottom into an upper unit layer, a middle unit layer, and a lower unit layer. The thickness of the upper unit layer is L1, %; the thickness of the middle unit layer is L2, %; and the thickness of the lower unit layer is L3, %; where L1, L2, and L3 are the percentages of each layer's thickness relative to the total thickness of the material layers excluding the thickness of the spacer layers. The percentage of each layer relative to the total thickness of the material layers is determined by the following formula:

[0067]

[0068] L2 = 1 - L1 - L3 ... (Equation 3)

[0069] In the formula, r is the average particle size of the sintering raw material, mm; M is the moisture content of the sintering raw material, %; C is the carbon content of the sintering raw material, %; L is the total thickness of the material layer, cm; d is the total thickness of the two separating layers, cm; α, β, γ, and δ are adjustment coefficients, with α ranging from 0.2 to 0.8, β ranging from 0.2 to 0.8, γ ranging from 1 to 3, and δ ranging from 2 to 5.

[0070] According to a second embodiment of the present invention, a system for sintering and cooling layered fabric is provided.

[0071] A layered sintering and cooling system includes a sintering machine 1, a sintering trolley 2, a material feeding device 3, an ignition device 4, a flue gas treatment device 5, a sinter separation device 6, and an annular cooler 7. The sintering trolley 2 is mounted on the sintering machine 1, and the material feeding device 3 and ignition device 4 are both positioned above the sintering trolley 2. A large flue 8 is located below the sintering machine 1, and the flue gas treatment device 5 is connected to the large flue 8. Based on the movement direction of the sintering trolley 2, the material feeding device 3 is positioned upstream of the ignition device 4. The material outlet of the sintering machine 1 is connected to the material inlet of the sinter separation device 6, and the material outlet of the sinter separation device 6 is connected to the material inlet of the annular cooler 7. At least two layers of sintering raw material unit layers are laid on the sintering machine 1, with a separating layer between adjacent sintering raw material unit layers. The system includes 2 to 6 annular coolers 7, and the sinter separation device 6 has the same number of material outlets as the annular coolers 7. Preferably, the spacer material in the spacer layer is any one or more of coal gangue, blast furnace slag, steel slag, limestone, and lump ore.

[0072] Preferably, the sintering machine 1 is provided with three layers of sintering raw material unit layers and two layers of spacer material layers, with the sintering raw material unit layers and spacer material layers laid alternately. The system also includes a sintered finished product bin 9. The annular cooler 7 includes a high-temperature annular cooler 701 and a low-temperature annular cooler 702. The sintered ore separation device 6 is provided with a high-temperature material outlet, a medium-temperature material outlet, and a low-temperature material outlet. The low-temperature material outlet is connected to the sintered finished product bin 9, the medium-temperature material outlet is connected to the low-temperature annular cooler 702, and the high-temperature material outlet is connected to the high-temperature annular cooler 701.

[0073] Example 1

[0074] A layered sintering and cooling system includes a sintering machine 1, a sintering trolley 2, a material feeding device 3, an ignition device 4, a flue gas treatment device 5, a sinter separation device 6, and an annular cooler 7. The sintering trolley 2 is mounted on the sintering machine 1, and the material feeding device 3 and ignition device 4 are both positioned above the sintering trolley 2. A large flue 8 is located below the sintering machine 1, and the flue gas treatment device 5 is connected to the large flue 8. Based on the movement direction of the sintering trolley 2, the material feeding device 3 is positioned upstream of the ignition device 4. The material outlet of the sintering machine 1 is connected to the material inlet of the sinter separation device 6, and the material outlet of the sinter separation device 6 is connected to the material inlet of the annular cooler 7. At least two layers of sintering raw material unit layers are laid on the sintering machine 1, with a separating layer between adjacent sintering raw material unit layers. The system includes two annular coolers 7, and the sinter separation device 6 has the same number of material outlets as the annular coolers 7. The spacer material in the spacer layer is coal gangue.

[0075] Example 2

[0076] The system repeats Example 1, except that it also includes a sintered finished product silo 9. The two annular coolers 7 are a high-temperature annular cooler 701 and a low-temperature annular cooler 702. The sintered ore separation device 6 is provided with a high-temperature material outlet, a medium-temperature material outlet, and a low-temperature material outlet. The low-temperature material outlet is connected to the sintered finished product silo 9, the medium-temperature material outlet is connected to the low-temperature annular cooler 702, and the high-temperature material outlet is connected to the high-temperature annular cooler 701.

[0077] Application Example 1

[0078] A method for sintering and cooling layered fabric, using the system described in Example 2, includes the following steps:

[0079] 1) The sintering raw materials and spacers are alternately laid on the sintering trolley to obtain a mixed sintering material layer with a three-layer sintering material unit structure formed by two layers of spacers from top to bottom. From top to bottom, the mixed sintering material layer consists of an upper unit layer of sintering raw materials, a first spacer layer, a middle unit layer of sintering raw materials, a second spacer layer, and a lower unit layer of sintering raw materials. The sintering machine is started to sinter the mixed sintering material layer to obtain a sintering ore upper unit layer, a first spacer layer, a middle unit layer of sintering ore, a second spacer layer, and a lower unit layer of sintering ore from top to bottom.

[0080] 2) The average temperature of the upper unit layer of sinter is 85℃, the average temperature of the middle unit layer is 402℃, and the average temperature of the lower unit layer is 1037℃. After each unit layer of sinter is crushed independently, the upper unit layer is transported to the finished sinter bin, the middle unit layer is sent to a low-temperature ring cooler, and the lower unit layer is sent to a high-temperature ring cooler. After cooling, a finished sinter with a capacity of 650t / h is obtained. The low-temperature ring cooler produces 1811 Nm of finished sinter. 3 The low-temperature exhaust gas at 265℃ was cooled by a high-temperature annular cooler to obtain 1321 Nm³ / h. 3 High-temperature exhaust gas at 718℃ / h, 2241Nm 3 / h of medium-temperature exhaust gas at 530℃ and 2514Nm 3 Low-temperature exhaust gas at 252℃ / h is used for sintering ignition, medium-temperature exhaust gas for hot air sintering, and high-temperature exhaust gas for power generation.

[0081] The spacer material in the first and second spacer layers is coal gangue with a particle size of 7 mm. Both the first and second spacer layers contain coke. The first spacer layer has a thickness of 4 cm and a carbon content of 27%, while the second spacer layer has a thickness of 4 cm and a carbon content of 23%.

[0082] Calculate the percentage of each material layer in the total material layer thickness according to Equations 1 to 3:

[0083]

[0084] L2 = 1 - L1 - L3 = 41.43%

[0085] In the formula, r is the average particle size of the sintering raw material, which is 5 mm; M is the moisture content of the sintering raw material, which is 9.6%; C is the carbon content of the sintering raw material, which is 3.5%; L is the total thickness of the material layer, which is 100 cm; d is the total thickness of the two separating layers, which is 8 cm; α, β, γ, and δ are adjustment coefficients, where α is 0.4, β is 0.3, γ is 1.8, and δ is 2.8.

[0086] The thickness of the upper unit layer of the sintering raw material is 18cm; the thickness of the middle unit layer of the sintering raw material is 36cm; and the thickness of the lower unit layer of the sintering raw material is 38cm.

[0087] The application of Example 1 was repeated, except that the thickness of the first and second spacer layers and their carbon content were changed. The specific parameters are shown in Table 1.

[0088] Table 1

[0089]

[0090]

[0091] Application Example 14

[0092] The application of Example 1 is repeated, except that the spacer material in the first and second spacer layers is replaced with blast furnace slag with a particle size of 8 mm. Both the first and second spacer layers contain coke. The thickness of the first spacer layer is 6 cm and the carbon content is 4.5%. The thickness of the second spacer layer is 7 cm and the carbon content is 3.5%.

[0093] Example 14 was repeated, except that the thickness of the first and second spacer layers and their carbon content were changed. The specific parameters are shown in Table 2.

[0094] Table 2

[0095]

[0096] Application Example 23

[0097] Example 1 was repeated, except that the spacer material in the first spacer layer was replaced with limestone, and the spacer material in the second spacer layer was replaced with lump ore. The average particle size of the limestone and lump ore was 8 mm. The thickness of the first spacer layer was 2 cm, and the carbon content was 1%. The thickness of the second spacer layer was 7 cm, and the carbon content was 3.5%.

[0098] Example 23 was repeated, except that the thickness of the first and second spacer layers and their carbon content were changed. The specific parameters are shown in Table 3.

[0099] Table 3

[0100]

[0101] Application Example 32

[0102] Example 1 was repeated, except that the thicknesses of the upper unit layer, the middle unit layer, and the lower unit layer of the sintering raw material were changed. The specific parameters are shown in Table 4.

[0103] Table 4

[0104]

[0105]

[0106] Comparative Example 1

[0107] A sintering and cooling method, the method comprising the following steps:

[0108] 1) Lay the sintering raw materials on the sintering trolley to obtain a sintering material layer; start the sintering machine to sinter the mixed sintering material layer to obtain a sintered ore unit layer.

[0109] 2) The average temperature of the sinter layer is 750℃. The sinter unit layer is fed into an annular cooler, and after cooling, a finished sinter with a capacity of 650t / h is obtained. The annular cooler produces 2328 Nm of sinter. 3 / h of medium-temperature exhaust gas at 351℃ and 3519Nm 3 Low-temperature exhaust gas at 179℃ / h is used for sintering ignition, while medium-temperature exhaust gas is used for hot air sintering.

[0110] Comparative Example 2

[0111] A method for sintering and cooling layered fabric, the method comprising the following steps:

[0112] 1) The sintering material is divided into 3 layers and laid on the sintering trolley. The adjacent sintering material unit layers are separated by partitions to obtain a mixed sintering material layer with a 3-layer sintering material unit layer structure. From top to bottom, the sintering material upper unit layer, the sintering material middle unit layer, and the sintering material lower unit layer are arranged. The sintering machine is started to sinter the mixed sintering material layer to obtain the uppermost sintering ore upper unit layer. However, the sintering material middle unit layer and the sintering material lower unit layer are almost not sintered, and the sintering fails.

[0113] 2) The average temperature of the upper unit layer of sinter is 93℃. After crushing the upper unit layer of sinter, 281t / h of finished sinter is obtained.

[0114] The partition is 3cm thick and has ventilation holes. The thickness of the upper unit layer of the sintering raw material is 22cm; the thickness of the middle unit layer of the sintering raw material is 28cm; and the thickness of the lower unit layer of the sintering raw material is 33cm.

[0115] The sintering energy consumption, waste heat power generation, and annular cooler load of Examples 1-27 and Comparative Examples 1 and 2 were statistically analyzed, and the results are shown in Table 4.

[0116] Table 4

[0117]

[0118]

[0119]

[0120] Based on the above experimental data, the present invention provides a layered material sintering and cooling method, which sets up multiple sintering raw material unit layers for sintering, sets up spacer layers, limits the carbon content in the spacer layers, and limits the thickness of the spacer layers according to different spacer materials, and cools the sintered ore at different temperatures after sintering separately, thereby improving the cooling efficiency and the heat recovery rate of the sintered ore, while reducing the workload of the ring cooler and saving the initial investment of the ring cooler.

Claims

1. A method for sintering and cooling layered fabric, characterized in that: The method includes the following steps: 1) The sintering raw materials and spacers are alternately laid on the sintering trolley to obtain a mixed sintering material layer with multiple sintering material unit layer structures formed by separating the sintering raw materials from top to bottom by at least one layer of spacers; the sintering machine is started to sinter the mixed sintering material layer to obtain at least two sintering ore unit layers with different temperatures. 2) Based on the different temperatures of each sinter unit layer, each sinter unit layer is independently crushed and cooled to obtain the finished sinter.

2. The method according to claim 1, characterized in that: In step 1), the number of spacer layers in the mixed sintering material layer is 1 to 5; there is a sintering raw material unit layer on the upper and lower sides of any spacer layer.

3. The method according to claim 2, characterized in that: In step 1), the number of spacer layers in the mixed sintering material layer is 2 to 3.

4. The method according to claim 2, characterized in that: The thickness of each spacer layer may be the same or different; the thickness of each sintering raw material unit layer may be the same or different.

5. The method according to any one of claims 1-4, characterized in that: The spacer material in the spacer layer is a mixture of any one or more of the following: coal gangue, blast furnace slag, steel slag, limestone, and lump ore.

6. The method according to any one of claims 1-4, characterized in that: The thickness of the spacer layer is 1~10cm; and / or The spacer material has a particle size of 5~10mm.

7. The method according to claim 6, characterized in that: The thickness of the spacer layer is 2-8 cm; and / or The spacer material has a particle size of 6-9 mm.

8. The method according to claim 5, characterized in that: The spacer layer is any one of the following: a 3-5cm thick coal gangue layer, a 5-8cm thick blast furnace slag layer, a 5-8cm thick steel slag layer, a 1-3cm thick limestone layer, and a 5-8cm thick lump ore layer.

9. The method according to claim 8, characterized in that: The spacer layer also contains fuel.

10. The method according to claim 9, characterized in that: The fuel is coke.

11. The method according to claim 9, characterized in that: The amount of fuel added to the interlayer is controlled so that the total carbon content in the coal gangue layer is 20%~30%, the total carbon content in the blast furnace slag layer, steel slag layer, and lump ore layer is 3%~5%, and the total carbon content in the limestone layer is 0.5%~2%.

12. The method according to claim 11, characterized in that: The carbon content in the lower interlayer is less than that in the upper interlayer.

13. The method according to any one of claims 1-4 and 7-12, characterized in that: The method of cooling each sintered ore unit layer independently is as follows: the obtained sintered ore unit layers are sent to different annular coolers for cooling according to different temperatures, and the waste heat collected by the different annular coolers of different qualities is utilized separately.

14. The method according to claim 13, characterized in that: Based on the temperature of each sintered ore unit layer obtained after sintering, the different sintered ore unit layers are divided into medium-temperature layers and high-temperature layers, and optionally include or exclude low-temperature layers; the sintered ore in the low-temperature layer is transported to the sintered finished product warehouse, the sintered ore in the medium-temperature layer is sent to the low-temperature ring cooler for cooling, and the sintered ore in the high-temperature layer is sent to the high-temperature ring cooler for cooling.

15. The method according to claim 14, characterized in that: The temperature of the sinter in the low-temperature layer is 50~200℃; the temperature of the sinter in the medium-temperature layer is 150~800℃; and the temperature of the sinter in the high-temperature layer is 700~1200℃.

16. The method according to claim 13, characterized in that: The specific method of utilizing the waste heat of different qualities collected by different annular coolers is as follows: the low-temperature annular cooler produces low-temperature cooling waste gas; the front section of the high-temperature annular cooler produces high-temperature cooling waste gas, the middle section of the high-temperature annular cooler produces medium-temperature cooling waste gas, and the rear section of the high-temperature annular cooler produces low-temperature cooling waste gas; the obtained low-temperature cooling waste gas is used for sintering ignition or hot air sintering, and the high-temperature cooling waste gas is used for power generation.

17. The method according to any one of claims 1-4, 7-12, and 15-16, characterized in that: In the mixed sintering material layer, there are two spacer layers, which divide the sintering material from top to bottom into an upper unit layer, a middle unit layer, and a lower unit layer. The thickness of the upper unit layer is L1,%; the thickness of the middle unit layer is L2,%; and the thickness of the lower unit layer is L3,% , where L1, L2, and L3 are the percentages of each layer's thickness relative to the total thickness of the material layer excluding the spacer layer thickness. The percentage of each layer relative to the total thickness of the material layer is determined by the following formula: ； ； ； In the formula, r is the average particle size of the sintering raw material, mm; M is the moisture content of the sintering raw material, %; C is the carbon content of the sintering raw material, %; L is the total thickness of the material layer, cm; d is the total thickness of the two separating layers, cm; α, β, γ, and δ are adjustment coefficients, where α ranges from 0.2 to 0.8, β ranges from 0.2 to 0.8, γ ranges from 1 to 3, and δ ranges from 2 to 5.

18. A system for use in the method of any one of claims 1-17, characterized in that: The system includes a sintering machine (1), a sintering trolley (2), a feeding device (3), an ignition device (4), a flue gas treatment device (5), a sintered ore separation device (6), and an annular cooler (7); the sintering trolley (2) is mounted on the sintering machine (1), and the feeding device (3) and the ignition device (4) are both mounted above the sintering trolley (2); a large flue (8) is provided below the sintering machine (1), and the flue gas treatment device (5) is connected to the large flue (8); according to the direction of movement of the sintering trolley (2), the feeding device... The device (3) is located upstream of the ignition device (4); the material outlet of the sintering machine (1) is connected to the material inlet of the sintered ore separation device (6), and the material outlet of the sintered ore separation device (6) is connected to the material inlet of the ring cooler (7); at least two layers of sintering raw material unit layers are laid on the sintering machine (1), and a separating layer is laid between adjacent sintering raw material unit layers; the system includes a total of 2 to 6 ring coolers (7), and the sintered ore separation device (6) has the same number of material outlets as the ring coolers (7).

19. The system according to claim 18, characterized in that: The spacer material in the spacer layer is any one or more of coal gangue, blast furnace slag, steel slag, limestone, and lump ore.

20. The system according to claim 18 or 19, characterized in that: The sintering machine (1) is provided with 3 layers of sintering raw material unit layer and 2 layers of spacer material layer, and the sintering raw material unit layer and spacer material layer are laid alternately; the system also includes a sintering finished product silo (9); the ring cooler (7) includes a high temperature ring cooler (701) and a low temperature ring cooler (702); the sintered ore separation device (6) is provided with a high temperature material outlet, a medium temperature material outlet and a low temperature material outlet, the low temperature material outlet is connected to the sintering finished product silo (9), the medium temperature material outlet is connected to the low temperature ring cooler (702), and the high temperature material outlet is connected to the high temperature ring cooler (701).

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