Blast furnace blow-in hearth filling method

Abstract

The invention discloses a hearth filling method for blow-in of a blast furnace, the blast furnace comprises a hearth, a bosh, a bosh, a body and a throat from bottom to top, a hearth charging area is divided into a first layer, a second layer, a third layer and a fourth layer from bottom to top, and the hearth filling method comprises the steps that the first layer is filled with blast furnace water granulated slag; the second layer is filled with coke; the third layer is filled with miscellaneous trees; tiling a layer of sleepers on the fourth layer; rectangular small bags are piled by sleepers in a central area above the fourth layer; and a circle of sleepers are densely and vertically laid on the periphery above the fourth layer corresponding to the position of the tuyere. Blast furnace water granulated slag bottoming promotes rapid formation of an initial slag layer of a blast furnace, a refractory material at the bottom of a hearth is protected, coke facilitates slag iron flowing, a dead iron layer of the hearth is activated, weedtree replaces sleepers, the blow-in cost is greatly reduced, the sleepers guarantee stable, reliable and smooth blow-in of the blast furnace, and rapid blow-in for production reaching can be achieved.

Description

Technical Field

[0001] The present application belongs to the technical field of blast furnace opening, and in particular relates to a hearth filling method for blast furnace opening. Background Art

[0002] In the modern steel industry, blast furnace start-up is one of the most challenging key processes in metallurgical production. Generally, the cost of blast furnace start-up is high, and the start-up and material preparation cycle is long, which seriously affects the profits of steel companies. Summary of the invention

[0003] The present application aims to solve at least one of the technical problems existing in the prior art. To this end, the present application proposes a hearth filling method for blast furnace start-up to reduce the cost of blast furnace start-up and achieve rapid production of the blast furnace start-up.

[0004] The present application provides a hearth filling method for a blast furnace. The blast furnace includes a hearth, a belly, a waist, a furnace body and a throat from bottom to top. The hearth charging area is divided into a first layer, a second layer, a third layer and a fourth layer from bottom to top. The hearth filling method includes:

[0005] Fill the first layer with blast furnace slag;

[0006] Fill the second layer with coke;

[0007] Fill the third layer with miscellaneous wood;

[0008] Lay a layer of sleepers flat on the fourth floor;

[0009] In the central area above the fourth floor, small rectangular packages are built with sleepers;

[0010] A circle of sleepers are densely laid vertically around the air vents above the fourth floor.

[0011] According to the hearth filling method for blast furnace opening of the present application, the rapid formation of the initial slag layer of the blast furnace is promoted by laying the bottom with blast furnace slag, the refractory material at the bottom of the hearth is protected, the coke is conducive to the flow of slag and iron, and the dead iron layer in the hearth is activated. Miscellaneous wood replaces sleepers, which greatly reduces the cost of opening the furnace. Sleepers ensure that the blast furnace is opened safely, reliably and smoothly. The overall material preparation is easy and the cost is low, and the furnace can be opened and put into production quickly, which greatly improves the economic benefits of steel enterprises.

[0012] According to one embodiment of the present application, the blast furnace has a capacity of 3200m 3 ~4500m 3 The first layer is located on the upper side of the refractory material of the blast furnace bottom, the second layer is located on the lower side of the center line of the iron mouth of the blast furnace and is spaced from the center line of the iron mouth of the blast furnace, and the upper surface of the third layer is located 460mm below the center line of the tuyere of the blast furnace.

[0013] According to one embodiment of the present application, the length of the sleeper is 2500 mm, the width of the sleeper is 220 mm, and the height of the sleeper is 160 mm.

[0014] According to one embodiment of the present application, in the step of filling the first layer with blast furnace slag, 35 tons to 45 tons of blast furnace slag is filled in the first layer in a flat manner.

[0015] According to one embodiment of the present application, in the step of filling the second layer with coke, 40 to 45 tons of coke are placed in the second layer in two batches at an inclination angle of 20°.

[0016] According to one embodiment of the present application, the second layer is distributed through the furnace top matrix With the laying method at an inclination angle of 20°, 20 tons of coke were laid in the first batch and 25 tons of coke were laid in the second batch.

[0017] According to one embodiment of the present application, the step of filling the third layer with miscellaneous wood includes:

[0018] Stop filling the third layer with miscellaneous wood until it is 1m below the center line of the tuyere;

[0019] Workers enter the furnace to level the miscellaneous wood;

[0020] After taking the furnace out of the vat, the workers continue to fill it with miscellaneous wood to the top of the third layer.

[0021] According to one embodiment of the present application, in the step of filling the third layer with miscellaneous wood, the miscellaneous wood is filled in by removing two sets of symmetrically arranged multiple pairs of tuyere from the hearth of the blast furnace, and the miscellaneous wood is naturally loaded through the two sets of multiple pairs of tuyere.

[0022] According to one embodiment of the present application, the diameter of the miscellaneous wood is ≤400 mm, and the length is ≤4000 mm.

[0023] According to one embodiment of the present application, the volume of the rectangular package is 10m 3 ~15m 3 , and the center of gravity of the rectangular package is located on the center line of the blast furnace.

[0024] Additional aspects and advantages of the present application will be given in part in the description below, and in part will become apparent from the description below, or will be learned through the practice of the present application. BRIEF DESCRIPTION OF THE DRAWINGS

[0025] The above and / or additional aspects and advantages of the present application will become apparent and easily understood from the description of the embodiments in conjunction with the following drawings, in which:

[0026] Figure 1 It is a schematic diagram of the layout of the blast furnace filling method provided in the embodiment of the present application;

[0027] Figure 2 It is a schematic flow chart of a blast furnace hearth filling method provided in an embodiment of the present application.

[0028] Reference numerals:

[0029] 100, blast furnace; 110, hearth; 111, first layer; 112, second layer; 113, third layer; 114, fourth layer; 115, rectangular small bag; 120, belly; 130, waist; 140, body; 150, throat; 160, center line of tuyere; 170, center line of iron mouth; 180, net coke. DETAILED DESCRIPTION

[0030] As the starting point of the blast furnace service life, the quality of furnace opening is directly related to the life cycle and production efficiency of the blast furnace. According to industry statistics, about 68% of the cases of shortened blast furnace maintenance cycles are directly related to improper furnace opening operations. During the furnace opening process, the design and implementation quality of the furnace charging plan have a decisive influence on core parameters such as the establishment of the blast furnace thermal state, the flow performance of slag and iron, and the smoothness of the furnace charge. Traditional blast furnace opening and charging generally adopts the "full sleeper filling" mode, which has significant technical and economic defects:

[0031] ①Material costs remain high: 4000m per seat 3 The start-up of a blast furnace requires 800 to 1,200 cubic meters of high-quality sleepers. According to the current market price, the purchase cost of sleepers alone is 3 to 5 million yuan. The start-up data of a steel company in 2019 showed that the cost of sleepers accounted for 62.3% of the total cost of furnace materials.

[0032] ② Resource sustainability crisis: High-quality sleepers must be made of hardwood species that are more than 30 years old, and the growth period of a single tree is as long as 25 to 35 years. Statistics from a forest farm in Northeast my country show that every time a large blast furnace is started, it is equivalent to consuming 10 hectares of mature forest resources.

[0033] ③ Operational complexity increases: full sleeper filling requires manual stacking layer by layer, 4000m 3 It takes more than 200 skilled workers to work continuously for 72 hours to charge a high-grade blast furnace, with labor costs exceeding one million yuan. An analysis of a furnace opening accident at a steel plant in 2018 showed that manual operation errors caused local filling density deviations of more than 15%.

[0034] ④Imbalance of thermodynamic performance: The full sleeper structure is prone to form a "thermal barrier" effect during the combustion stage, and the furnace heating rate is difficult to break through the technical bottleneck of 3°C / min, resulting in the production time being extended to 7-10 days. Experimental data from a metallurgical research institute showed that the furnace temperature field uniformity coefficient under traditional processes was only 0.67.

[0035] The improvement schemes tried by the industry in recent years still have obvious defects. Mixed filling process: Mixed loading of sleepers and coke is adopted, which reduces the amount of sleepers to 600m 3 , but the permeability difference coefficient of the material layer increased to 2.8, and the probability of local pipeline travel after the furnace was turned on and the air was supplied increased by 40%. Synthetic material substitution: Although the experimentally applied resin-based composite materials reduce wood consumption, their combustion calorific value is 35% lower than that of sleepers, and they produce harmful gases such as cyanide. The measured emission concentration exceeds the standard by 2.7 times. Structural optimization plan: The "center column + sleeper ring" structure proposed by a design institute reduces the amount of sleepers by 15%, but the construction accuracy requirement is increased to ±5mm, and the qualified rate in actual projects is less than 60%.

[0036] Given the cost pressure in the era of low profits in the steel industry, furnace cost control has become a core competitiveness factor for enterprises. The proportion of sleeper procurement costs in the total furnace cost needs to be reduced from more than 60% in traditional processes to less than 30%, which puts forward rigid requirements for the innovation of filling materials. The financial analysis of a listed steel company shows that for every 10% reduction in furnace cost, the corresponding cost per ton of iron can be reduced by 1.2 yuan. Calculated based on an annual production scale of tens of millions of tons, the annual efficiency increase exceeds tens of millions of yuan.

[0037] After the implementation of the Forest Resources Protection Law, the purchase of large sleepers faces strict approval procedures. The start-up of a key steel company's 2021 furnace project was delayed by 45 days due to sleeper supply issues, resulting in direct economic losses of over 100 million yuan. At the same time, the international carbon tariff mechanism requires the traceability of wood carbon footprints, and the implicit carbon emissions per cubic meter of sleepers reach 0.78 tons of CO2 equivalent.

[0038] In view of this, in order to promote the green and low-carbon development of the steel industry, reduce the amount of sleepers while ensuring the reliability of the furnace opening process, and achieve rapid production of the blast furnace, the present invention proposes a furnace loading method for blast furnace opening, so as to reduce the blast furnace opening cost and achieve rapid production of the blast furnace.

[0039] The embodiments of the present application are described in detail below, and examples of the embodiments are shown in the accompanying drawings, wherein the same or similar reference numerals throughout represent the same or similar elements or elements having the same or similar functions. The embodiments described below with reference to the accompanying drawings are exemplary and are only used to explain the present application, and cannot be understood as limiting the present application.

[0040] Reference below Figure 1 and Figure 2 A hearth filling method for blast furnace opening according to an embodiment of the present application is described.

[0041] See also Figure 1 and Figure 2 , an embodiment of the present application provides a hearth filling method for blast furnace opening.

[0042] The blast furnace 100 includes, from bottom to top, a furnace hearth 110 , a furnace belly 120 , a furnace waist 130 , a furnace shaft 140 and a furnace throat 150 .

[0043] The throat 150 is located at the top of the blast furnace 100 and is the entrance for the charge to enter the blast furnace 100. The main function of the throat 150 is to evenly distribute the charge on the cross section of the furnace. The furnace body 140 is in the shape of a right frustum that is larger at the bottom and smaller at the top. It is the main component of the blast furnace 100 and occupies a considerable spatial height of the blast furnace 100. The furnace waist 130 is located at the position with the largest diameter of the blast furnace 100 and is the transition area between the furnace belly 120 and the furnace body 140. The distribution of coal gas in this area is relatively uniform, which creates favorable conditions for sufficient material and energy exchange between the charge and the coal gas. The furnace belly 120 is in the shape of an inverted frustum that is larger at the top and smaller at the bottom. As the charge gradually descends into the furnace belly 120 under the action of gravity, it is strongly impacted and heated by the rising coal gas below. In this area, the charge begins to undergo a softening and partial melting process.

[0044] As the foundation of the blast furnace 100, the hearth 110 is the area with the highest temperature and the most complex working conditions in the entire blast furnace 100 system. Its internal space is used to store high-temperature molten iron and slag. The bottom of the hearth 110 is paved with thick, high-temperature and corrosion-resistant refractory materials. These refractory materials are in direct contact with high-temperature molten iron and slag, and are subject to huge thermal stress and chemical erosion.

[0045] The charging area of ​​the furnace 110 is divided into a first layer 111, a second layer 112, a third layer 113 and a fourth layer 114 from bottom to top. Specifically, the first layer 111 is located above the refractory material at the bottom of the furnace 110. The method for charging the furnace 110 includes: step 210, step 220, step 230, step 240, step 250 and step 260.

[0046] Step 210, filling the first layer 111 with blast furnace slag;

[0047] Step 220, filling the second layer 112 with coke;

[0048] Step 230, filling the third layer 113 with miscellaneous wood;

[0049] Step 240, laying a layer of sleepers on the fourth layer 114;

[0050] Step 250, stacking a rectangular small package 115 with sleepers in the central area above the fourth layer 114;

[0051] Step 260: densely lay a circle of sleepers vertically around the position of the air outlet above the fourth layer 114.

[0052] In step 210, blast furnace slag is filled into the first layer 111. The blast furnace slag is a byproduct of ironmaking in the blast furnace 100. The blast furnace slag is transported into the furnace 110 using a feeding device and evenly filled into the first layer 111. During the filling process, attention should be paid to controlling the filling speed and filling amount to ensure that the slag is evenly spread on the bottom of the furnace 110 and the thickness is consistent. The filling thickness of the first layer 111 of blast furnace slag can be adjusted according to the size of the blast furnace 100 and actual production needs.

[0053] In step 220, suitable coke is selected as the filler of the second layer 112. The coke should have high strength, good air permeability and reactivity. Specifically, the coke can be dry quenched coke for smelting in the blast furnace 100. The coke is transported to the furnace 110 by the feeding equipment and filled into the second layer 112, above the blast furnace slag. During the filling process, attention should be paid to the stacking method of the coke, so that the coke can be evenly distributed as much as possible to avoid the situation where the local stacking is too high or too low. The filling thickness of the second layer 112 of coke can be adjusted according to the actual situation of the blast furnace 100.

[0054] In the first layer 111 and the second layer 112 at the bottom, blast furnace slag and coke have no special physical and chemical composition requirements, are easy to obtain, and are cheap. The blast furnace slag in the first layer 111 at the bottom can promote the rapid formation of the initial slag layer of the blast furnace 100, absorb harmful elements, and reduce chemical erosion on the bottom of the furnace 110. At the same time, it has the functions of energy absorption and shock absorption, and protects the refractory materials at the bottom of the furnace 110 during the filling process, greatly reducing the impact of raw materials such as ore loaded into the deep material line at the initial stage of furnace opening on the bottom of the furnace 110. The addition of coke in the second layer 112 is conducive to the flow of slag iron and activates the dead iron layer of the furnace 110. Illustratively, the particle size range of blast furnace slag can be controlled between 5mm-20mm, which is conducive to the uniform distribution of slag at the bottom of the furnace 110 and improves the quality of the initial slag layer. The particle size range of coke can be controlled between 25mm-80mm to ensure that it can form a good air permeability channel in the furnace 110, which is conducive to the flow of slag and iron and activates the dead iron layer of the furnace 110.

[0055] In step 230, suitable miscellaneous wood is selected as the filler of the third layer 113. Miscellaneous wood refers to general wood, which has low requirements on its shape and size, and has a short growth cycle and is easy to obtain. Miscellaneous wood can be various common woods, such as poplar, willow, etc. Before using the miscellaneous wood, it can be cleaned and processed to remove impurities and bark on the surface to ensure the combustion performance of the miscellaneous wood. The processed miscellaneous wood is transported to the furnace 110 through the feeding equipment and filled into the third layer 113. During the filling process, attention should be paid to the arrangement of the miscellaneous wood, and the miscellaneous wood should be staggered as much as possible to improve the air permeability in the furnace 110. Miscellaneous wood is easy to obtain and low in cost. Using miscellaneous wood to replace a large number of sleepers greatly reduces the cost of opening a furnace, reduces the felling of old trees, and protects the environment.

[0056] In step 240, only one layer of sleepers is loaded, which greatly reduces the sleeper consumption for furnace opening. In combination with the rectangular small package 115 in step 250 and a circle of sleepers vertically laid along the periphery of the inner wall of the furnace 110 in step 260, the thermal efficiency of the furnace 110 is improved, which promotes the rapid heating of the furnace 110, protects the tuyere, and quickly frees up space for the charge to descend, ensuring that the blast furnace 100 is opened steadily, reliably and smoothly, and can achieve rapid furnace opening and production.

[0057] When the blast furnace 100 is started, the portion above the fourth layer 114 to the furnace belly 120 is filled with clean coke 180, and the furnace waist 130 and the furnace body 140 can be filled with charge materials normally according to the furnace start-up batching plan.

[0058] According to the hearth filling method for blast furnace opening provided in the embodiment of the present application, the blast furnace slag is used to spread the bottom to promote the rapid formation of the initial slag layer of the blast furnace 100, protect the refractory materials at the bottom of the hearth 110, coke is conducive to the flow of slag and iron, and activates the dead iron layer of the hearth 110. Miscellaneous wood replaces sleepers, which greatly reduces the cost of opening the furnace. The sleepers ensure that the blast furnace 100 is opened safely, reliably and smoothly. The overall material preparation is easy and low-cost, and rapid furnace opening and production can be achieved, greatly improving the economic benefits of steel enterprises.

[0059] See also Figure 1 According to some embodiments of the present application, the furnace capacity of the blast furnace 100 may be 3200m 3 ~4500m 3 The first layer 111 is located on the upper side of the refractory material of the furnace bottom of the blast furnace 100, the second layer 112 can be located on the lower side of the iron mouth center line 170 of the blast furnace 100 and can be spaced from the iron mouth center line 170 of the blast furnace 100, and the upper surface of the third layer 113 is located 460 mm below the tuyere center line 160 of the blast furnace 100.

[0060] The furnace capacity of the blast furnace 100 in the embodiment of the present application is 3200m 3 ~4500m 3 This range of furnace capacity covers medium-sized to large blast furnaces 100, which is widely representative in modern steel production. Blast furnaces 100 of different furnace capacity have differences in structural size, production capacity, and thermal system. The filling method of the furnace 110 of the embodiment of the present application can be effectively adapted to ensure efficient and stable furnace operation. For example, the furnace capacity of the blast furnace 100 can be 3200m 3 、3400m 3 、3600m 3 、3800m 3 4000m 3 4200m 3 、4500m 3 or 3200m3 -4500m 3 There is no specific limitation on other volumes between the two.

[0061] The first layer 111 is laid on the refractory material at the bottom of the blast furnace 100. The blast furnace slag at this position can quickly absorb the heat at the bottom of the furnace 110 at the beginning of the furnace opening, and promote the rapid formation of the initial slag layer. On the one hand, the initial slag layer formed by the slag can buffer the direct impact of molten iron on the refractory material at the bottom of the furnace, reduce the penetration and erosion of molten iron, protect the refractory material at the bottom of the furnace, and extend its service life; on the other hand, it is conducive to the convergence and separation of slag and iron in the early stage, laying a good foundation for the subsequent normal smelting process. In the actual furnace opening process, it can be observed through thermal imaging monitoring equipment that within a short period of time after the furnace is opened and ignited, the temperature of the slag layer area at the bottom of the furnace rises rapidly and tends to stabilize, indicating that the initial slag layer begins to form and play a role.

[0062] The coke filled in the second layer 112 is located at the lower side of the center line 170 of the iron mouth of the blast furnace 100 and is separated from the center line 170 of the iron mouth of the blast furnace 100 by a certain distance. The coke at this position plays a vital role in the opening process of the blast furnace 100. First, it can provide good air permeability for the bottom of the furnace 110, so that the rising coal gas can pass smoothly, avoid the formation of a coal gas dead zone at the bottom of the furnace 110, and promote gas circulation and heat exchange in the furnace 110; secondly, when slag iron begins to be produced in the furnace, the coke layer can effectively promote the flow of slag iron, activate the dead iron layer of the furnace 110, prevent slag iron from accumulating and clogging at the bottom of the furnace 110, and ensure the normal tapping of the iron mouth.

[0063] The coke layer is spaced a certain distance from the center line 170 of the iron mouth, which can avoid direct contact between the coke and the iron mouth, prevent excessive scouring and erosion of the refractory materials in the iron mouth area by the high-temperature coke during the furnace opening process, and is conducive to maintaining the integrity and stability of the iron mouth, ensuring that the iron mouth can maintain a good working condition at the beginning of the furnace opening, and creating conditions for smooth iron tapping. The interval setting can form a reasonable space near the iron mouth, which is convenient for the slag iron to flow and gather more smoothly to the iron mouth under the action of gravity, reduce the retention and blockage of slag iron around the iron mouth, and improve the efficiency and smoothness of slag iron discharge. Appropriate spacing helps to form a more uniform temperature distribution in the furnace 110. The iron mouth area is relatively independent of the coke layer, and the temperature near the iron mouth can be adjusted by controlling the heat transfer in other areas to prevent the iron mouth from affecting its normal function due to excessively high or low temperature, which is conducive to the stability and optimization of the temperature field of the entire furnace 110.

[0064] The upper surface of the third layer 113 of miscellaneous wood is located 460 mm below the center line 160 of the tuyere of the blast furnace 100. The area of ​​the center line 160 of the tuyere is where the hot air is sprayed into the furnace, with extremely high temperature and fast airflow speed. The distance between the upper surface of the miscellaneous wood layer and the center line 160 of the tuyere is 460 mm, which can ensure that the miscellaneous wood can fully absorb the heat from the tuyere area during the furnace heating process, burn quickly, provide additional heat for the furnace, and accelerate the heating and reduction process of the charge; it can also avoid blocking the tuyere to ensure the smoothness of the air intake; it can also avoid the miscellaneous wood burning too violently and too fast due to being too close to the tuyere, affecting the stability and continuity of the combustion. At the same time, the void structure formed after the miscellaneous wood is burned helps to improve the air permeability in the furnace, creating favorable conditions for the subsequent descent of the charge and the rise of the coal gas.

[0065] According to some embodiments of the present application, the length of the sleeper is 2500 mm, the width of the sleeper is 220 mm, and the height of the sleeper is 160 mm.

[0066] When the sleepers are laid flat on the fourth layer 114, sleepers of this specification can better cover the surface of the furnace 110, ensuring the uniformity and stability of the laying. The length of 2500mm allows the sleepers to, to a certain extent, cross the local irregular areas in the furnace 110 when they are laid in the furnace 110, reducing the impact of the uneven surface of the furnace 110 on the laying of sleepers. Among them, when paving the sleepers of the fourth layer 114, a dense laying method is adopted, and the joints are nailed with grab nails. With a size combination of 220mm in width and 160mm in height, only one layer of sleepers is needed to have suitable supporting strength and stability. When bearing the pressure of the upper furnace charge and subsequent operations, it is not easy to tilt or break, which greatly saves the use of sleepers.

[0067] Moreover, after the fourth layer 114 sleepers are laid flat, combined with the condition that the top surface of the third layer 113 of miscellaneous wood is located 460mm below the center line 160 of the blast furnace 100 tuyere, the sleepers with a height of 160mm make the top surface of the sleepers just 300mm away from the center line of the tuyere after the fourth layer 114 is laid. After the blast furnace 100 is opened and air is supplied, the hot air is ejected from the tuyere at a high speed, and the interval can effectively guide the hot air to spread evenly in the furnace. The hot air will not directly impact the sleeper layer, avoiding premature combustion or displacement of the sleepers due to the impact of the hot air, thereby ensuring the stability of the sleeper layer structure. At the same time, the hot air can fully contact the charge in the furnace, promoting the preheating and reduction reaction of the charge.

[0068] When stacking the rectangular small package 115 in the central area above the fourth layer 114, the sleepers of the above size can also be used. The length of 2500mm is convenient for neat stacking and connection, which can ensure the regularity and stability of the rectangular small package 115. Through reasonable arrangement and combination, these sleepers can be used to stack a rectangular small package 115 with a length, width and height between 2.0m and 3.0m respectively (such as 2.5m long, 2.5m wide, 1.2m high, etc. The specific dimensions can be adjusted according to actual conditions). The small package stacked by sleepers of this specification can provide additional support and cushioning for the furnace during the furnace opening process, and also help to guide the distribution of the airflow and furnace charge in the furnace, making it more reasonable and uniform. For example, in the process of coal gas rising in the initial stage of furnace opening, the rectangular small package 115 can play a certain role in blocking and diverting the flow of coal gas, prompting the coal gas to diffuse more evenly in the furnace, thereby improving the heat exchange efficiency in the furnace 100.

[0069] When a circle of sleepers are densely laid vertically at the position corresponding to the tuyere above the fourth layer 114, the width of 220 mm and the height of 160 mm allow the sleepers to be closely arranged to form an effective blocking and protective structure. The vertically laid sleepers can prevent the high-temperature airflow and charge in the furnace from directly impacting the tuyere area, protecting the safety and normal operation of the tuyere equipment. At the same time, the gaps and arrangement between the sleepers also help maintain the air permeability of the tuyere area, ensuring that the hot air can be smoothly sprayed into the furnace and fully react with the charge. It is understandable that when the sleepers are laid vertically, the joints between the sleepers are also grasped with nails to ensure integrity and structural stability.

[0070] According to the sleeper specifications provided in the embodiments of the present application, sleepers of this specification cooperate with other filling layers (such as blast furnace slag layer, coke layer, and miscellaneous wood layer) to form a stable and reasonable filling structure of the furnace 110. The support and buffering effect of the sleepers can protect the filling layer below from being damaged by the pressure above, and also provide a stable bearing foundation for the filling above. During the furnace opening process, the various filling layers interact with each other through heat transfer and physical support, and jointly promote the establishment of the initial thermal state of the blast furnace 100 and the smooth flow of slag and iron. For example, the heat released by the sleepers during the combustion process can complement the combustion heat of miscellaneous wood and coke, accelerate the rise of the temperature in the furnace, and enable the blast furnace 100 to reach the thermal state required for normal production more quickly.

[0071] According to some embodiments of the present application, in step 210, in the step of filling the first layer 111 with blast furnace slag, the first layer 111 is filled with 35 tons to 45 tons of blast furnace slag in a flat manner.

[0072] The filling amount of blast furnace slag must ensure that the blast furnace slag evenly covers the furnace bottom to form an initial slag layer of sufficient thickness and stability. If the filling amount is too small, the refractory material of the furnace bottom may not be fully protected, and the furnace bottom may be easily corroded when molten iron is produced in the initial stage of furnace opening; if the filling amount is too large, the air permeability of the lower part of the furnace cylinder 110 may deteriorate, affecting the smoothness of the rise of coal gas and the descent of furnace charge.

[0073] Exemplarily, the amount of blast furnace slag filled in the first layer 111 may be 35 tons, 37 tons, 39 tons, 40 tons, 42 tons, 43 tons, 45 tons or other values ​​between 35 tons and 45 tons, without specific limitation.

[0074] According to some embodiments of the present application, in step 220, in the step of filling the second layer 112 with coke, 40 tons to 45 tons of coke may be placed in the second layer 112 in two batches at an inclination angle of 20°.

[0075] Coke is placed in the bottom of the hearth 110 at a central angle of 20°, and is rolled from the center to the edge to form a natural stacking angle with a high center and a low edge, thereby improving the circulation effect of molten iron in the hearth 110 when the air volume is small at the initial stage of furnace opening, promoting the smooth operation of the blast furnace 100, and reducing damage to cooling equipment such as tuyere.

[0076] The filling amount of the second layer 112 of coke is determined by comprehensively considering the size of the hearth 110 of the blast furnace 100, the position of the iron mouth centerline 170, and the need to promote the flow of slag and iron and activate the dead iron layer of the hearth 110. By way of example, the amount of coke in the second layer 112 can be 40 tons, 41 tons, 42 tons, 43 tons, 44 tons, 45 tons or other values ​​between 40 tons and 45 tons, without specific limitation.

[0077] 40 tons to 45 tons of coke are distributed into the furnace 110 in two batches. The first batch of distribution can first form a basic coke layer at the bottom of the furnace 110 to provide stable support and guidance for subsequent distribution. During the first batch of distribution, the operator can fine-tune the distribution parameters, such as distribution speed, chute rotation angle, etc., according to actual conditions to ensure that the initial distribution of coke meets the requirements. The second batch of distribution is supplemented and improved on the basis of the first batch to further optimize the distribution and accumulation state of coke. Distribution in two batches can also reduce the impact of excessive single distribution on the existing packing layer in the furnace 110 and reduce the impact on the bottom structure of the furnace 110. For example, in actual operation, about 20 tons to 22.5 tons of coke can be distributed in the first batch to form a rough coke outline, then check and evaluate the distribution effect, adjust the parameters of the second batch of distribution according to the situation, and then distribute the remaining coke to make the entire second layer 112 of coke layer achieve the best air permeability and stability.

[0078] According to some embodiments of the present application, the second layer 112 can be formed by the furnace top distribution matrix With the laying method at an inclination angle of 20°, 20 tons of coke were laid in the first batch and 25 tons of coke were laid in the second batch.

[0079] Divide the 150° circumference of the furnace throat into three equal parts. The distribution mode corresponds to the distribution operation of these three parts, and it is carried out according to a specific rule and sequence. When the distribution is carried out at an inclination angle of 20°, the combination of this distribution matrix and the inclination angle can achieve a more uniform distribution of coke in the furnace 110. Specifically, in the first batch of 20

[0080] When distributing tons of coke, the material is distributed through the distribution chute according to The coke is evenly distributed in three equally divided areas of the furnace throat 150 according to the pattern and 20° inclination angle, forming a relatively uniform initial coke layer foundation in the furnace hearth 110. When the second batch of 25 tons of coke is distributed, the existing coke layer is supplemented and improved according to the same pattern and inclination angle to further optimize the accumulation state of the coke. This distribution method can avoid the situation where the coke is locally accumulated too high or too low in the furnace hearth 110, ensure the uniformity of the air permeability in the furnace hearth 110, and facilitate the sufficient heat exchange and chemical reaction between the rising coal gas and the coke, thereby improving the thermal efficiency and reaction efficiency of the blast furnace 100.

[0081] The first batch of 20 tons of coke can form a basic coke layer at the bottom of the furnace 110 to provide stable support and guidance for subsequent distribution. During the first batch of distribution, the operator can fine-tune the distribution parameters such as distribution speed, chute rotation angle, etc. according to actual conditions to ensure that the initial distribution of coke meets the requirements. The requirements of the distribution mode. Through real-time monitoring of the distribution process, such as using cameras and laser rangefinders installed on the furnace roof, observe the placement and accumulation of coke in the three equally divided areas of the furnace throat 150, and adjust the distribution parameters in time. The second batch of 25 tons of coke is supplemented and improved on the basis of the first batch, further optimizing the distribution and accumulation of coke. The distribution in two batches can also reduce the impact of excessive single-time distribution on the existing filler layer in the furnace hearth 110 and reduce the impact on the bottom structure of the furnace hearth 110. At the same time, this batch distribution method can better control the distribution of coke in the furnace hearth 110, making it more in line with the needs of blast furnace 100 smelting, such as forming a suitable coke accumulation below the iron mouth center line 170, providing a good channel for the flow of slag iron, and activating the dead iron layer of the furnace hearth 110.

[0082] In one example, to implement a furnace top distribution matrix Coke is placed in two batches at an angle of 20°. Specialized distribution equipment can be used, such as the distribution chute on the top of the 100-meter bellless blast furnace. The chute is equipped with a precise mechanical transmission and control system, which can achieve accurate adjustment of the inclination angle and follow the During the charging process, the operator monitors the charging status in real time through the monitoring system, including the coke drop point, stacking height, charging speed and other parameters in the three equally divided areas of the furnace throat 150. According to the requirements of the mode, the system will automatically control the chute to carry out the distribution operation in the three areas of the furnace throat 150 in sequence, and adjust the inclination angle to 20°. If problems such as uneven coke distribution or inclination deviation are found during the distribution process, the operator can intervene in time and manually adjust the angle and distribution speed of the chute to ensure that the coke is distributed according to the predetermined The furnace is arranged in a furnace cavity 110 with a pattern and a 20° inclination angle.

[0083] According to some embodiments of the present application, step 230, the step of filling the third layer 113 with miscellaneous wood, includes:

[0084] Step 231, filling the third layer 113 with miscellaneous wood until it is 1 m below the center line 160 of the tuyere and stopping;

[0085] Step 232: Workers enter the furnace 110 to level the wood;

[0086] Step 233 , after leaving the furnace 110 , the worker continues to fill the miscellaneous wood to the top of the third layer 113 .

[0087] In step 231, the third layer 113 is filled with miscellaneous wood until it is 1 m below the center line 160 of the tuyere. 3 -4500m 3 When loading the wood in the blast furnace 100 with a furnace capacity of 100, a suitable loading device, such as a loader or a belt conveyor, is used to transport the processed wood into the furnace 110. During the loading process, the operator needs to pay close attention to the stacking height of the wood, and accurately control the loading height by using a height measuring device installed in the furnace 110 or referring to the scale marked on the wall of the furnace 110 in advance, and stop loading when the height reaches 1m below the center line 160 of the tuyere.

[0088] In step 232, the worker enters the furnace 110 to level the wood. Before the worker enters the furnace 110, it is necessary to ensure that the furnace environment is safe, such as good ventilation and suitable temperature. After the worker enters the furnace 110, he uses tools (such as rakes, shovels, etc.) to sort the piled wood to make the surface of the wood as flat as possible. The purpose of the leveling operation is to ensure the uniformity of subsequent wood filling and the stability of the airflow and charge descent in the furnace. If the surface of the wood is uneven, it may cause the wood to pile up too high or too low in a local area, affecting the combustion effect and the air permeability in the furnace.

[0089] In step 233, the worker continues to fill the wood to the top of the third layer 113 after leaving the furnace 110. After the worker completes the leveling operation and safely leaves the furnace 110, the loading device is started again to continue to fill the wood into the furnace 110 until the top of the third layer 113 is reached. According to the present invention, the top position of the third layer 113 is set to the position where the upper surface is 460 mm below the center line 160 of the tuyere of the blast furnace 100. In the filling process at this stage, it is also necessary to control the filling speed and stacking of the wood to ensure that the wood is evenly distributed and avoid the occurrence of voids or localized stacking.

[0090] According to some embodiments of the present application, in step 230 of filling the third layer 113 with miscellaneous wood, the miscellaneous wood is filled in by removing two sets of symmetrically arranged multiple pairs of tuyere from the furnace table of the blast furnace 100, and the miscellaneous wood is naturally loaded through the two sets of multiple pairs of tuyere.

[0091] The number and distribution of the second set of tuyere are determined according to the design and production requirements of the blast furnace 100. Before disassembly, a comprehensive safety inspection of the blast furnace 100 is required to ensure that the pressure in the furnace has been released and the temperature has dropped to a safe range. It should be noted here that when filling in miscellaneous wood, the bottom temperature of the furnace 110 is ≤40°C. Operators need to wear protective equipment and use appropriate tools (such as wrenches, cranes, etc.) to disassemble the second set of tuyere in the prescribed order and method. The purpose of disassembling multiple pairs of symmetrically arranged second sets of tuyere is to ensure that the miscellaneous wood can be evenly loaded into the furnace 110, while avoiding affecting the stability of the blast furnace 100 structure due to the disassembly of too many sets of tuyere on one side.

[0092] In one example, four sets of wood can be removed from the four symmetrical directions of the stove, and miscellaneous wood can be naturally loaded into the four sets of wood.

[0093] According to some embodiments of the present application, the diameter of the miscellaneous wood is ≤400 mm and the length is ≤4000 mm.

[0094] If the size of the wood is too large, it may not be properly stacked in the furnace 110, which will cause difficulty in filling and affect the uniformity and compactness of the filling. Secondly, from the perspective of combustion effect, smaller wood can increase the contact area with the air, and can burn more fully after the furnace is ignited, which is conducive to quickly raising the temperature of the furnace 100 and creating good temperature conditions for subsequent coke combustion and normal operation of the blast furnace 100.

[0095] In addition, wood that meets the requirements is relatively easy to obtain, the market supply is relatively sufficient, and the procurement cost is low. Smaller wood is more convenient to transport and can be transported by ordinary transportation vehicles and transportation methods. Wood with smaller diameter and length is easier to process, and the processing equipment and manpower required are relatively less. From the perspective of procurement, transportation and processing, the cost of furnace opening can be reduced.

[0096] According to some embodiments of the present application, the volume of the rectangular package 115 can be 10m 3 ~15m 3 , and the center of gravity of the rectangular package 115 is located on the center line of the blast furnace 100.

[0097] For example, the volume of the rectangular package 115 may be 10 m 3 、11m 3 、12m 3 、13m 3 、14m 3 、15m 3 or 10m 3 -15m 3 There is no specific limitation on other values ​​between .

[0098] The center of gravity of the rectangular package 115 is located on the center line of the blast furnace 100, which is very important for the stability and safety of the blast furnace 100. The blast furnace 100 needs to maintain a good balance and uniform force distribution during the opening process to avoid problems such as furnace body tilting and local overheating. When the center of gravity of the package is located on the center line of the blast furnace 100, it can ensure that the filler in the furnace 110 is evenly distributed in the circumferential direction, making the blast furnace 100 more balanced in terms of heat and force.

[0099] According to some embodiments of the present application, a blast furnace 100 of a certain ironmaking plant A has an effective volume of 3972m 3 , 36 tuyere, furnace 110 diameter 13.4m, dead iron layer thickness 2.8m, furnace 110 height 5.2m, distance from the bottom edge of tuyere to the top edge of furnace 110 1.1m, furnace 110 cross-sectional area 141.0m 2 , the volume from the center line of the tuyere 160 to the lower edge of the tuyere 0.3m, and the section from the lower edge of the tuyere 0.3m to the bottom of the furnace 110 is 588.21m 3 After the overhaul of blast furnace 100, the charging method of furnace hearth 110 is as follows:

[0100] Take 35t of self-produced slag from blast furnace A 100 and fill it in the first layer 111 at the bottom of the furnace 110 in a flat manner;

[0101] Through the stove top cloth matrix At an inclination angle of 20°, 20 tons and 25 tons of coke are placed into the second layer 112 in two batches respectively;

[0102] Remove the two sets of tuyere No. 1, 10, 19, and 28 from the furnace platform respectively. After the bottom temperature of the furnace cylinder 110 is detected to be ≤40℃, load the dry and tar-free miscellaneous wood with a diameter of ≤400mm and a length of ≤4000mm from the four sets into the third layer 113. Place the miscellaneous wood evenly and horizontally. After loading it to 1m below the center line 160 of the tuyere, stop loading, enter the furnace cylinder 110, level the miscellaneous wood, and then continue loading the miscellaneous wood to 460mm below the center line 160 of the tuyere after exiting the furnace cylinder 110;

[0103] The dry tar-free sleepers are densely arranged and laid flat in one layer on the fourth layer 114 above the miscellaneous wood. The cross-sectional area of ​​the furnace 110 is 141m 2 The standard size of the sleeper is 2500mm×220mm×160mm (0.088m3), and the area of ​​each sleeper is 0.55m 2 , 256 sleepers are closely packed. The inclined sleepers around the tuyere protect the tuyere. The circumference of the furnace 110 around the tuyere is 42m, and the number of sleepers around the tuyere is 191. The joints of each sleeper are nailed firmly. A total of 114 sleepers are piled up for 10m in the center area above the fourth layer 114. 3 There are 115 rectangular small packages, and the center of gravity of the rectangle is located on the center line of the blast furnace 100. The total number of sleepers for the three items is 561.

[0104] After the loading of sleepers in the furnace hearth 110 is completed, the remaining part above the fourth layer 114 to the furnace belly 120 is filled with net coke 180. The remaining parts of the blast furnace 100 (furnace waist 130, furnace body 140 and furnace throat 150) begin to be charged with materials according to the furnace charging plan. After all the loading is completed, the blast furnace 100 is ignited and started as required. After the A blast furnace 100 is started, the furnace condition is smooth.

[0105] The volume from the 0.3m section at the lower edge of the tuyere to the bottom of the furnace 110 is 588.21m 3 , assuming that the entire space is 2500mm×220mm×160mm(0.088m 3 ) Theoretically, 588.21 / 0.088=6684 sleepers are needed to fill the furnace, but this time only 8.4% of the theoretical amount was used, which greatly reduced the amount of sleepers, reduced the furnace cost, and protected the environment.

[0106] The terms "first", "second", etc. in the specification and claims of the present application are used to distinguish similar objects, and are not used to describe a specific order or sequence. It should be understood that the data used in this way can be interchangeable under appropriate circumstances, so that the embodiments of the present application can be implemented in an order other than those illustrated or described here, and the objects distinguished by "first", "second", etc. are generally of one type, and the number of objects is not limited. For example, the first object can be one or more. In addition, "and / or" in the specification and claims represents at least one of the connected objects, and the character " / " generally indicates that the objects associated with each other are in an "or" relationship.

[0107] In the description of the present application, it should be understood that the terms "center", "longitudinal", "lateral", "length", "width", "thickness", "up", "down", "front", "back", "left", "right", "vertical", "horizontal", "top", "bottom", "inside", "outside", "clockwise", "counterclockwise", "axial", "radial", "circumferential" and the like indicate orientations or positional relationships based on the orientations or positional relationships shown in the accompanying drawings, and are only for the convenience of describing the present application and simplifying the description, and do not indicate or imply that the referred device or element must have a specific orientation, be constructed and operated in a specific orientation, and therefore should not be understood as a limitation on the present application.

[0108] In the description of this application, "first feature" or "second feature" may include one or more of the features.

[0109] In the description of the present application, “plurality” means two or more.

[0110] In the description of the present application, a first feature being “on” or “under” a second feature may include that the first and second features are directly in contact with each other, or may include that the first and second features are not in direct contact with each other but are in contact with each other via another feature therebetween.

[0111] In the description of the present application, “above”, “over” and “above” a first feature to a second feature includes the first feature being directly above and obliquely above the second feature, or simply means that the first feature is horizontally higher than the second feature.

[0112] In the description of this specification, the description with reference to the terms "one embodiment", "some embodiments", "illustrative embodiments", "examples", "specific examples", or "some examples" means that the specific features, structures, materials, or characteristics described in conjunction with the embodiment or example are included in at least one embodiment or example of the present application. In this specification, the schematic representation of the above terms does not necessarily refer to the same embodiment or example. Moreover, the specific features, structures, materials, or characteristics described may be combined in any one or more embodiments or examples in a suitable manner.

[0113] Although the embodiments of the present application have been shown and described, those skilled in the art will appreciate that various changes, modifications, substitutions and variations may be made to the embodiments without departing from the principles and spirit of the present application, and that the scope of the present application is defined by the claims and their equivalents.

Claims

1. A method for filling a hearth during blast furnace operation, characterized in that: The blast furnace comprises a hearth, a belly, a furnace waist, a furnace body and a furnace throat from bottom to top, and the hearth charging area is divided into a first layer, a second layer, a third layer and a fourth layer from bottom to top. The hearth filling method comprises: Filling the first layer with blast furnace slag; Filling the second layer with coke; Fill the third layer with miscellaneous wood; Laying a layer of sleepers on the fourth layer; A rectangular parcel is built with sleepers in the central area above the fourth layer; A circle of sleepers is densely laid vertically at the position of the vent corresponding to the periphery above the fourth layer.

2. The hearth filling method for blast furnace opening according to claim 1, characterized in that: The blast furnace has a capacity of 3200m 3 ~4500m 3 The first layer is located on the upper side of the refractory material of the furnace bottom of the blast furnace, the second layer is located on the lower side of the center line of the iron mouth of the blast furnace and is spaced from the center line of the iron mouth of the blast furnace, and the upper surface of the third layer is located 460 mm below the center line of the tuyere of the blast furnace.

3. The hearth filling method for blast furnace opening according to claim 2, characterized in that: The length of the sleeper is 2500 mm, the width of the sleeper is 220 mm, and the height of the sleeper is 160 mm.

4. The hearth filling method for blast furnace opening according to claim 2 or 3, characterized in that: In the step of filling the first layer with blast furnace slag, the first layer is filled with 35 tons to 45 tons of blast furnace slag in a flat manner.

5. The hearth filling method for blast furnace opening according to claim 2 or 3, characterized in that: In the step of filling the second layer with coke, 40 to 45 tons of coke are placed in the second layer in two batches at an inclination angle of 20 degrees.

6. The hearth filling method for blast furnace opening according to claim 5, characterized in that: The second layer is distributed through the furnace top matrix With the laying method at an inclination angle of 20°, 20 tons of coke were laid in the first batch and 25 tons of coke were laid in the second batch.

7. The hearth filling method for blast furnace opening according to claim 2 or 3, characterized in that: The step of filling the third layer with miscellaneous wood comprises: The third layer is filled with miscellaneous wood until it is 1m below the center line of the tuyere and then stopped; Workers enter the furnace to level the miscellaneous wood; After the workers take the furnace out of the vat, they continue to fill the miscellaneous wood to the top of the third layer.

8. The method for filling a hearth during blast furnace opening according to claim 7, characterized in that: In the step of filling the third layer with miscellaneous wood, the miscellaneous wood is filled in by removing two sets of symmetrically arranged multiple pairs of tuyere from the furnace platform of the blast furnace, and the miscellaneous wood is naturally loaded through the two sets of multiple pairs of tuyere.

9. The hearth filling method for blast furnace opening according to claim 2 or 3, characterized in that: The diameter of the miscellaneous wood is ≤400mm, and the length is ≤4000mm.

10. The hearth filling method for blast furnace opening according to claim 2 or 3, characterized in that: The volume of the rectangular package is 10m 3 ~15m 3 , and the center of gravity of the rectangular package is located on the center line of the blast furnace.

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