Blast furnace coal injection process using furfural carbon in iron and steel enterprises

Abstract

The invention relates to the technical field of blast furnace ironmaking, and discloses a blast furnace coal injection process using furfural carbon in iron and steel enterprises, which comprises the following steps: S1, loading furfural carbon with water content lower than 50% and dry basis volatile component content lower than 75% into a furfural carbon storage bin with a sealing device through a conveying device; s2, the furfural carbon, anthracite and bituminous coal are weighed and then are loaded into a raw coal conveying belt of a powder making workshop according to the sequence that the anthracite is located at the lower part, the furfural carbon is located in the middle and the bituminous coal is located at the upper part; and S3, loading the furfural carbon and the pulverized coal into a medium-speed mill through a conveying belt, uniformly mixing, drying and crushing in the medium-speed mill to obtain mixed powder of which the particle size is smaller than 0.074 mm and accounts for 40-95% and the moisture content is smaller than 2.8%, and the bulk density of the mixed powder is 0.55-0.76 g / cm < 3 >. According to the invention, the application of furfural carbon in the field of steel production is expanded, the utilization value of furfural carbon is improved, the dependence of blast furnace ironmaking production on fossil fuel is reduced, and the carbon dioxide emission in the blast furnace process is reduced.

Description

Technical Field

[0001] This invention relates to the field of blast furnace ironmaking technology, and in particular to a blast furnace pulverized coal injection process using furfural carbon in iron and steel enterprises. Background Technology

[0002] Blast furnaces are currently the most efficient and lowest-cost ironmaking process, but they consume large amounts of coke and pulverized coal, resulting in high carbon emissions from steel products. This puts increasing pressure on the industry in the context of addressing climate change and promoting green and low-carbon development. Biomass energy, with its inherent low-carbon properties, is a key technology for partially replacing fossil fuels in blast furnace production, reducing carbon dioxide emissions during ironmaking. Furfural charcoal is a solid waste product from the production of furfural from agricultural and forestry waste (including corn cobs, bagasse, agricultural straw, and waste wood). It is characterized by its large production volume and low price, and is currently mainly used in organic fertilizer production, boiler fuel, and activated carbon production.

[0003] Furfural charcoal has a high moisture content (40%-60%) and a large particle size (average particle size around 5mm). Due to its high content of byproducts such as acetic acid, it has a pungent odor, requiring drying, grinding, and deodorization during use. Washing can remove the irritating odor, but this further increases the moisture content and introduces wastewater treatment issues. Baking can reduce the moisture content, but this significantly increases costs. Furthermore, furfural charcoal has a high volatile content, making it prone to ignition during drying, posing a safety hazard. The potential application of furfural charcoal derived from agricultural and forestry waste in blast furnace production could solve the problem of harmless treatment of solid waste from biomass chemical enterprises and reduce the reliance on fossil fuels in blast furnace ironmaking.

[0004] The blast furnace workshop of an ironmaking plant is equipped with complete raw material storage, weighing, blending, crushing, drying, and injection equipment. By adjusting the process parameters at each stage of the blast furnace pulverized coal injection process, furfural char can be dried, ground, deodorized, and mixed evenly with pulverized coal, thus serving as a low-carbon component of blast furnace pulverized coal for ironmaking production. Currently, there are no publicly reported cases of steel companies utilizing furfural char in blast furnace pulverized coal injection processes. Therefore, it is necessary to find a suitable process that combines the physicochemical properties of furfural char with the production process characteristics of blast furnace pulverized coal to safely, efficiently, cleanly, and with low carbon emissions, apply furfural char in the production of blast furnace pulverized coal. Summary of the Invention

[0005] The purpose of this invention is to address the above-mentioned problems by providing a blast furnace pulverized coal injection process for steel enterprises using furfural char. By adjusting the process parameters of each step in the blast furnace pulverized coal injection process, the invention enables the safe and efficient application of coarse-grained furfural char with high moisture content, high volatile matter, and a pungent odor in the blast furnace ironmaking field. This achieves the resource utilization of agricultural and forestry waste processing residues and reduces the dependence of blast furnace ironmaking production on fossil fuels, resulting in significant economic, social, and ecological benefits.

[0006] To achieve the above objectives, the technical solution adopted by the present invention is as follows: A blast furnace pulverized coal injection process for steel enterprises utilizing furfural carbon includes the following steps: S1: Furfural char with a moisture content of less than 50% and a dry basis volatile content of less than 75% is loaded into a furfural char storage silo with a sealing device through a conveying device. S2: Weigh the furfural char, anthracite, and bituminous coal and load them into the raw coal conveyor belt of the pulverizing workshop in the order of anthracite at the bottom, furfural char in the middle, and bituminous coal at the top. S3: The furfural char and coal powder are fed into a medium-speed mill via a conveyor belt, and then mixed, dried and pulverized in the medium-speed mill to obtain a mixed powder with a particle size of less than 0.074 mm accounting for 40% to 95% and a moisture content of less than 2.8%, and the bulk density of the mixed powder is 0.55 g / cm3 to 0.76 g / cm3. S4: The mixed powder is injected into the blast furnace tuyere through the pulverized coal silo, injection tank, pulverized coal distributor and injection gun, and burns in contact with high temperature oxygen-enriched air in the blast furnace tuyere swirling zone, providing heat and reducing agent for blast furnace smelting.

[0007] Preferably, the ash content of the furfural char dry basis in step S1 is less than 15%, and the furfural char is stored in the storage silo for no more than 15 days.

[0008] Preferably, in step S2, the furfural char, anthracite and bituminous coal are loaded into the storage bin using a feeder, weighed by a belt scale and then transported to the raw coal conveyor belt in the pulverizing workshop. The dry basis mass ratio of the furfural char, anthracite and bituminous coal is in the range of 1%-30%, 45%-60% and 10%-40%, respectively.

[0009] Preferably, in step S3, the inlet flue gas temperature of the medium-speed mill is 250-350℃, the oxygen content is 3%-10%, and the flue gas volume is 1000-2000 m³ / h. 3 / Mixed powder.

[0010] Preferably, in step S3, the calorific value of the mixed powder is greater than 25000kJ / kg, the ignition point is greater than 300℃, and the return flame length in the long-tube pulverized coal explosiveness test is less than 80mm.

[0011] Preferably, in step S4, the oxygen content in the pulverized coal silo is less than 5%, the storage time of the mixed powder in the pulverized coal silo does not exceed 12 hours, and the pulverized coal conveying gas in the injection tank is high-pressure nitrogen.

[0012] Preferably, in step S4, the amount of the mixed powder injected into the blast furnace tuyeres is 150-200 kg / t of molten iron, the temperature of the oxygen-enriched air is 1250-1350℃, the oxygen content in the air is 3%-10%, and the air volume is 5000-10000 m³ / t. 3 / t mixed powder.

[0013] Preferably, in step S4, the combustion rate of the mixed powder in the blast furnace tuyeres is greater than 60%, providing more than 11,000 kJ / kg of heat to the blast furnace. The reducing agent composition generated by combustion in the blast furnace tuyeres is in the range of CO: 30%-50%, H2: 5%-15%, N2: 40%-60%, and the reducing agent temperature is 2000℃-2300℃.

[0014] The beneficial effects of this invention are as follows: 1. This invention achieves the harmless and resource-based utilization of furfural char through its industrial application in blast furnace injection, which is conducive to the healthy development of the biomass chemical industry. 2. This invention achieves safe and efficient furfural char injection by systematically controlling the order and proportion of furfural char addition on the coal conveyor belt, as well as the temperature, oxygen content, storage time, and inert gas protection of the pulverizing and injection system. 3. This invention reduces the reliance of blast furnace ironmaking on fossil fuels by injecting furfural char into the blast furnace, accelerates the decarbonization process of blast furnace ironmaking, and promotes the green and low-carbon transformation of the steel industry. 4. This invention uses furfural char to replace pulverized coal injected into blast furnaces, which meets the national requirements for energy conservation and emission reduction. The low price of furfural char will significantly improve the economic benefits of blast furnace ironmaking enterprises. Attached Figure Description

[0015] To more clearly illustrate the technical solutions in the embodiments of this application, the accompanying drawings used in the embodiments will be briefly introduced below. Obviously, the drawings described below are only some embodiments of this application. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0016] Figure 1 This is a schematic diagram of a blast furnace pulverized coal injection process for steel enterprises utilizing furfural carbon, according to the present invention. Detailed Implementation

[0017] The present invention will be further described in detail below with reference to embodiments, so that the advantages and features of the present invention can be more easily understood by those skilled in the art, thereby providing a clearer and more explicit definition of the scope of protection of the present invention. Obviously, the described embodiments are only a part of the embodiments of the present invention, and not all of them. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0018] like Figure 1 As shown, this invention provides a blast furnace pulverized coal injection process for steel enterprises using furfural carbon. It provides a safe, efficient, clean, and low-carbon blast furnace pulverized coal injection process that utilizes furfural carbon in the production of pulverized coal. The disclosed furfural carbon has a moisture content of less than 50% and a volatile matter content on a dry basis of less than 75%. To overcome the characteristics of furfural carbon, such as high moisture content, low density, and irritating odor, the blast furnace pulverized coal injection process is adjusted accordingly: a furfural carbon storage silo is set up, equipped with a sealing device to reduce the diffusion and escape of the irritating odor and lower the oxygen content within the silo, thus preventing furfural carbon from escaping. To prevent spontaneous combustion of charcoal during storage and the resulting safety accidents, the safety of storage and use processes must be improved. The furfural charcoal storage silo is located between the blast furnace bituminous coal silo and the anthracite silo. Furfural charcoal, anthracite, and bituminous coal are conveyed to the pulverizing system via a pulverized coal conveyor belt. The loading order of the three materials on the conveyor belt is anthracite at the bottom, furfural charcoal in the middle, and bituminous coal at the top. The three materials are dried, pulverized, and mixed in a medium-speed mill to obtain a mixed powder with a particle size of less than 0.074 mm (40%–95%), a moisture content of less than 2.8%, and a bulk density of 0.55 g / cm³. 3 -0.76g / cm 3 This invention meets the performance requirements of blast furnace injection systems for solid fuel transportation and overcomes the drawback of low furfural density. The mixed powder is injected into the blast furnace tuyeres through pulverized coal bins, injection tanks, pulverized coal distributors, and injection lances. It burns in contact with high-temperature, oxygen-rich air in the tuyeres' swirling zone, providing heat and a reducing agent for blast furnace smelting. Since furfural is a biomass zero-carbon fuel, it effectively reduces fossil fuel consumption and carbon dioxide emissions during blast furnace smelting. This invention expands the application of furfural in steel production, enhances its utilization value, reduces steel production's dependence on fossil fuels, and lowers carbon dioxide emissions from blast furnace processes, aligning with the national green and low-carbon development strategy. Simultaneously, it can also reduce costs and increase efficiency for the furfural industry and steel enterprises, demonstrating significant economic, social, and ecological benefits.

[0019] Example 1 refer to Figure 1 As shown, this embodiment provides a blast furnace pulverized coal injection process for steel enterprises using furfural carbon, including the following steps: S1: Furfural char with a moisture content of less than 50% and a dry basis volatile content of less than 75% is loaded into a furfural char storage silo with a sealing device through a conveying device. Specifically, to overcome the characteristics of furfural char, such as high moisture content, low density, and pungent odor, the blast furnace pulverized coal injection process is adjusted accordingly: a furfural char storage silo is set up, equipped with a sealing device to reduce the diffusion and escape of the pungent odor and lower the oxygen content inside the silo, preventing spontaneous combustion of furfural char during storage and thus improving the safety of storage and use; the furfural char storage silo is located between the bituminous coal silo and the anthracite silo in the blast furnace, and the furfural char is stored in the silo for no more than 15 days. During long-term shutdowns, the furfural char in the silo must be emptied in a timely manner to avoid spontaneous combustion caused by long-term storage and resulting in safety accidents.

[0020] S2: Weigh the furfural char, anthracite, and bituminous coal and load them into the raw coal conveyor belt of the pulverizing workshop in the order of anthracite at the bottom, furfural char in the middle, and bituminous coal at the top. Specifically, the furfural char storage silo is located between the blast furnace pulverized coal and anthracite silos. Furfural char, anthracite, and bituminous coal are transported to the pulverizing system via the pulverized coal conveyor belt. Anthracite, furfural char, and bituminous coal are loaded from the stockpile into the anthracite, furfural char, and bituminous coal storage silos via grab hoppers. The anthracite, furfural, and bituminous coal storage silos are controlled to be loaded sequentially into the raw coal conveyor belt of the pulverizing workshop in the order of anthracite at the bottom, furfural char in the middle, and bituminous coal on top. The low moisture content of anthracite makes it suitable as a bottom material to form a stable base bed, overcoming the problem of furfural char easily sticking to the conveyor belt. The moderate moisture content and large particle size of bituminous coal, when covering the upper part of the furfural char layer, can suppress the formation of dust from the lightweight furfural char powder, reducing the risk of explosion. This overcomes the problems of furfural char easily sticking to the conveyor belt and the risk of explosion due to the formation of lightweight dust during transportation. Compositional analysis was performed on anthracite, furfural char, and bituminous coal. Furfural char had an as-received moisture content of less than 50%, a dry-basis volatile matter content of less than 75%, an as-received moisture content of 46.8%, a dry-basis volatile matter content of 68.2%, and a dry-basis ash content of less than 15%, for example, 6.2%. Anthracite had an as-received moisture content of less than 10%, for example, 6.7%, a dry-basis volatile matter content of less than 10%, for example, 9.3%, and a dry-basis ash content of less than 13%, for example, 11.5%. Bituminous coal had an as-received moisture content of less than 20%, for example, 16.7%, a dry-basis volatile matter content of less than 40%, for example, 33.6%, and a dry-basis ash content of less than 10%, for example, 7.1%. Under dry-basis conditions, the mass percentages of furfural char to anthracite and bituminous coal were in the ranges of 1%-30%, 45%-60%, and 10%-40%, respectively, for example, 3%, 57%, and 40%.

[0021] S3: The furfural charcoal and coal powder are fed into a medium-speed mill via a conveyor belt, where they are mixed, dried, and pulverized to obtain a mixed powder with a particle size of less than 0.074 mm accounting for 40% to 95%, a moisture content of less than 2.8%, and a bulk density of 0.55 g / cm³. 3 -0.76g / cm 3 ; Specifically, due to the low density of furfural char, it is easily carried away by the collecting airflow if not fully ground. To overcome this problem, after furfural char and coal powder are loaded into a medium-speed mill via a conveyor belt, they are crushed by the moving grinding rollers and grinding discs inside the mill. During the crushing process, the furfural char is mixed with anthracite and bituminous coal. At the same time, high-temperature flue gas of 250-350℃ is blown upward from below the grinding disc. For example, the inlet flue gas temperature of the medium-speed mill is 280℃ to avoid insufficient drying and reduced pulverizing efficiency caused by excessively low flue gas temperature and insufficient flue gas volume at the blast furnace inlet. Excessive flue gas temperature and oxygen content pose an explosion risk, while excessive flue gas volume will cause excessively high airflow velocity inside the medium-speed mill, resulting in furfural char being carried out by the high-speed airflow before being crushed, leading to excessively high moisture content and coarse particle size in the mixed powder. The pulverized particles are carried to the separator of the medium-speed mill. Coarse particles are separated and returned to the grinding disc for regrinding, while fine particles are collected with the flue gas. During this process, the high-temperature bituminous coal dries the pulverized coal particles, resulting in a mixed powder with a particle size of less than 0.074mm (40-95%, e.g., 75%), a moisture content of less than 2.8% (e.g., 1.8%), a calorific value greater than 25000kJ / kg (e.g., 26500kJ / kg), an ignition point greater than 300℃ (e.g., 345℃), and a return flame length less than 80mm (e.g., 0mm) in the long-tube pulverized coal explosiveness test. To ensure the safety of the pulverizing process, the oxygen content of the high-temperature flue gas at the inlet of the medium-speed mill is in the range of 3%-10% (e.g., 6%), and the flue gas volume is 1000-2000 m³ / h. 3 / Mixed powder, for example, the amount of high-temperature flue gas consumed in producing one ton of mixed powder is 1300m³. 3 When the calorific value is too low, it is difficult to provide sufficient heat to the blast furnace, resulting in an increase in the fuel ratio for blast furnace smelting. Excessive ignition point and return flame length pose an explosion risk. The bulk density of the mixed powder is 0.55 g / cm³. 3 -0.76g / cm 3 It meets the performance requirements of the blast furnace injection system for solid fuel transportation and overcomes the disadvantage of low density of furfural char.

[0022] S4: The mixed powder is injected into the blast furnace tuyere through the pulverized coal silo, injection tank, pulverized coal distributor and injection gun, and burns in contact with high temperature oxygen-enriched air in the blast furnace tuyere swirling zone, providing heat and reducing agent for blast furnace smelting.

[0023] Specifically, the mixed powder enters the coal powder silo for storage through the powder collection system. Nitrogen gas is introduced into the silo for protection, controlling the oxygen content to be less than 5%, for example, 4%, 3%, 2%, or 1%. Excessive oxygen content and prolonged storage time in the silo can easily lead to spontaneous combustion. Nitrogen is used as the gas for transporting the pulverized coal to the injection tank to improve the safety of the transportation process and avoid the risk of explosion in the injection pipe. Therefore, the storage time of the mixed powder in the coal powder silo does not exceed 12 hours, for example, 10 hours, 9 hours, 8 hours, 7 hours, or 6 hours. High-pressure nitrogen is used as the gas for transporting the coal powder in the injection tank. The mixed powder is transported to the injection tank through the coal powder silo and conveying pipeline, realizing the conversion between long-distance transportation and short-distance injection. In the injection tank, the fuel injection rate is controlled by a coal powder metering device to be 150-200 kg / t, for example, 160 kg / t molten iron, including 4.8 kg / t furfural char and a total of 155.2 kg / t anthracite and bituminous coal. kg / t molten iron, in which furfural char is transported to the pulverized coal distributor using high-pressure inert gas as the carrier gas. The pulverized coal distributor evenly distributes the mixed powder to the pulverized coal injection branch pipes, which are connected to the injection lances. The mixed powder is then injected into the blast furnace tuyeres through the injection lances. It burns in contact with high-temperature oxygen-enriched air in the blast furnace tuyeres' swirling zone. The oxygen-enriched air temperature is 1250-1350℃, for example 1250℃, with an oxygen content of 3%-10%, for example 4%, and an air volume of 5000-10000 m³ / t. 3 / t, the addition of furfural char increases the volatile matter content of the mixed powder, which can result in higher blast temperature and oxygen enrichment, enabling high pulverized coal injection ratio, high blast temperature, and high oxygen enrichment production. This is beneficial for improving the smelting efficiency of the blast furnace and reducing its fuel consumption, for example, in a 7500 m³ blast furnace. 3 / t of mixed powder; the combustion rate of the mixed powder in the blast furnace tuyeres is greater than 60%, for example, 65%, providing the blast furnace with more than 11000kJ / kg, for example, 13000kJ / t of heat. The reducing agent composition generated by combustion in the tuyeres is in the range of CO: 30%-50%, H2: 5%-15%, N2: 40%-60%, for example, CO: 35%, H2: 6%, N2: 59%, and the reducing agent temperature is 2000℃-2300℃, for example, 2250℃. The high-temperature reducing agent enters the charge column, providing heat and reducing agent for blast furnace smelting. Compared with the traditional fully pulverized coal blast furnace, it reduces fossil fuel consumption and carbon dioxide emissions by 1%-15%, achieving fossil fuel consumption of 470-500 kg / t of molten iron per ton of iron smelting and carbon dioxide emissions of 900-1100 kg / t of molten iron in the blast furnace process, realizing low-carbon and green production of blast furnace.

[0024] Examples 2-5 Examples 2-5 provide a blast furnace pulverized coal injection process for steel enterprises using furfural carbon. Compared with Example 1, the difference lies in changing the ratio of furfural carbon to pulverized coal in step S2. The specific values ​​of the furfural carbon to pulverized coal ratio for each example are shown in Table 1. Table 1. Ratio of furfural char and coal powder corresponding to Examples 2-5

[0025] The mixed powders prepared in each embodiment were sampled and their performance analyzed. The results are shown in Tables 2 and 3, respectively. Table 2 shows the properties of the mixed powders prepared in Examples 2-5.

[0026] Table 3. Effects of Mixed Powder Injection on Blast Furnace Smelting in Examples 2-5

[0027] As shown in Table 2, the proportion of mixed powder with a particle size less than 0.074 mm in Examples 2-5 ranged from 40% to 95%, specifically between 77% and 83%. The proportion of fine particles gradually increased with the increase of furfural char, mainly because furfural char has better grindability than coal powder. Increasing the furfural char ratio resulted in finer mixed powder particles prepared by the medium-speed mill, while maintaining the same milling parameters. Simultaneously, the moisture content of the mixed powder gradually increased, primarily due to the high moisture content in furfural char. Increasing the ratio increased the moisture content of the mixture. Under the same medium-speed milling process parameters, the moisture content of the mixed powder collected at the discharge port increased slightly by 1.9%-2.5%, but still met the requirements for fuel moisture content in the blast furnace injection process. Because furfural char has a high volatile matter content, replacing bituminous coal in blast furnace injection would cause a decrease in the calorific value of the mixture. With the increase of the furfural char ratio, the calorific value of the mixture remained between 25500-26300 kJ / kg. Furfural char has a high volatile content and a low ignition point. Increasing the proportion of furfural char lowers the ignition point of the mixed powder. When the proportion of furfural char increases from 2% to 17%, the ignition point decreases from 341℃ to 324℃. It can also be seen that the mixed powders of different schemes are not explosive, which can ensure the safe operation of the pulverizing and injection system.

[0028] As shown in Table 3, the heat provided to the blast furnace by the mixed powder injection gradually increases with the increase of the furfural char ratio, from 13100 kJ / kg mixed powder to 13250 kJ / kg mixed powder. Although the calorific value of furfural char is lower than that of bituminous coal, it has excellent combustion performance. With the increase of the furfural char ratio, the combustion rate of the mixed powder before the tuyeres increases (from 66.5% to 72.5%), and after complete combustion, it can provide more heat for blast furnace smelting. The volatile matter content of furfural char is relatively high, which increases the amount of reducing gas produced by combustion before the tuyeres. The increase in reducing gas is greater than the increase in combustion heat, causing a slight decrease in the reducing agent temperature, from 2213℃ to 2098℃. Blast furnace smelting has certain temperature requirements, but it needs more heat. Therefore, under the condition that the temperature meets the smelting requirements, the increase in heat is beneficial to improving the technical indicators of blast furnace smelting. After increasing the furfural char ratio, the amount of pulverized coal consumed in blast furnace smelting increased, decreasing from 162.3 kg / t of molten iron to 150.3 kg / t of molten iron. The fossil fuel consumption per ton of iron decreased from 506.6 kg / t of molten iron to 483.5 kg / t of molten iron. The carbon dioxide emissions from the blast furnace process decreased from 1087.3 kg / t of molten iron to 1017.6 kg / t of molten iron, representing reductions of 4.56% and 6.41% respectively. This is conducive to achieving energy conservation, emission reduction, and green development goals in blast furnace ironmaking production.

[0029] Examples 6-9 Examples 6-9 provide a blast furnace pulverized coal injection process for steel enterprises using furfural carbon. Compared with Example 3, the difference lies in the change of the temperature, oxygen content, and usage of the high-temperature flue gas in step S3. The specific values ​​of the high-temperature flue gas temperature, oxygen content, and usage for each example are shown in Table 4. Table 4 shows the temperature, oxygen content, and usage of the high-temperature flue gas corresponding to Examples 6-9.

[0030] The mixed powders prepared in each embodiment were sampled and their performance analyzed. The results are shown in Tables 5 and 6, respectively. Table 5 shows the properties of the mixed powders prepared in Examples 6-9.

[0031] Table 6 shows the effect of the mixed powder injection prepared in Examples 6-9 on blast furnace smelting.

[0032] As shown in Table 5, the moisture content of the mixed powders prepared in Examples 6-9 decreased with increasing high-temperature flue gas temperature, the particle size gradually decreased, the calorific value increased, and the ignition point slightly decreased. This indicates that increasing the flue gas temperature is beneficial for the rapid drying of furfural char and pulverized coal, and the reduction in moisture content has a certain promoting effect on improving grindability and increasing calorific value. Furthermore, increasing the flow rate of high-temperature flue gas can also accelerate the drying process of furfural char and pulverized coal, resulting in a smaller particle size, increased calorific value, and a slight decrease in ignition temperature. The rapid drying process has a certain improving effect on the pulverizing system. It can also be seen that the mixed powders are not explosive under different conditions, ensuring the safe operation of the pulverizing and injection systems. Under high flue gas temperatures, it is necessary to reduce the oxygen content in the flue gas to ensure the safety of the pulverizing process.

[0033] As can be seen from Table 6, by adjusting the process parameters of the pulverizing system, reducing the moisture content and particle size of the mixed powder, it is beneficial to its rapid combustion in front of the tuyeres, improving the combustion rate. At the same time, it can also provide more reducing agent and heat for blast furnace smelting. The mixed powder prepared in Examples 6-9 can meet the needs of blast furnace smelting. Compared with Example 3, it can reduce the amount of pulverized coal injection and reduce the carbon dioxide emissions in the blast furnace ironmaking process.

[0034] Examples 10-13 Examples 10-13 provide a blast furnace pulverized coal injection process for steel enterprises using furfural carbon. Compared with Example 8, the oxygen-enriched air temperature, oxygen content, and air volume in step S4 are changed. The specific values ​​of oxygen-enriched air temperature, oxygen content, and air volume for each example are shown in Table 7. Table 7 shows the oxygen-enriched air temperature, oxygen content, and air volume corresponding to Examples 10-13.

[0035] The parameters in each embodiment were subjected to blast furnace injection smelting, and the results are shown in Table 8: Table 8 shows the effect of the mixed powder injection prepared in Examples 6-9 on blast furnace smelting.

[0036] As shown in Table 8, increasing the oxygen-enriched air temperature in Examples 10-13 helps reduce fuel consumption, increase the reducing agent temperature and the combustion rate of the mixed powder, thus improving the technical indicators of blast furnace smelting. Increasing the oxygen content of the hot blast helps increase the reducing agent temperature and combustion rate, but it reduces the amount of oxygen-enriched air consumed per ton of iron produced, and the heat brought into the furnace by the oxygen-enriched air is reduced, which will cause a slight increase in combustion consumption. Reducing the blast volume is not conducive to the combustion of the mixed powder in front of the blast furnace tuyeres, increasing the fuel consumption per ton of iron produced. When the blast volume is small, the proportion of furfural char can be appropriately increased to improve the combustion rate of the mixed powder and improve the economic and technical indicators of blast furnace smelting.

[0037] Comparative Example 1 Comparative Example 1 provides a blast furnace pulverized coal injection process for steel enterprises using furfural carbon. Compared with Example 3, the difference is that the form of furfural carbon storage in step S1 is changed to open-air storage, and it is added by grab bucket. This causes the coal powder shed to be filled with a pungent odor, affecting the normal production of workers and forcing them to stop using furfural carbon.

[0038] Comparative Example 2 Comparative Example 2 provides a blast furnace pulverized coal injection process using furfural carbon in an iron and steel enterprise. Compared with Example 3, the difference is that the order of adding furfural carbon, anthracite, and bituminous coal in step S2 is changed. The furfural carbon is added at the bottom, the anthracite in the middle, and the bituminous coal at the top. During use, the furfural carbon adheres severely on the conveyor belt, forcing the machine to stop for cleaning, affecting the normal production of blast furnace ironmaking, and causing economic losses of up to 1.5 million yuan.

[0039] Comparative Example 3 Comparative Example 3 provides a blast furnace pulverized coal injection process for steel enterprises using furfural carbon. Compared with Example 3, the difference is that the order of adding furfural carbon, anthracite, and bituminous coal in step S2 is changed to anthracite at the bottom, bituminous coal in the middle, and furfural carbon at the top. During use, furfural carbon generates light dust during transportation, and the dust concentration in the conveyor corridor exceeds the standard, causing the safety monitoring equipment to alarm and the conveyor belt to stop urgently.

[0040] The above description is merely an illustrative embodiment of the present invention and is not intended to limit the present invention in any form or substance. It should be noted that any improvements and additions made by those skilled in the art without departing from the method of the present invention should also be considered within the scope of protection of the present invention. At the same time, any equivalent changes, modifications and evolutions made to the above embodiments based on the essential technology of the present invention shall still fall within the scope of protection of the present invention.

Claims

1. A blast furnace pulverized coal injection process for steel enterprises utilizing furfural carbon, characterized in that, Includes the following steps: S1: Furfural char with a moisture content of less than 50% and a dry basis volatile content of less than 75% is loaded into a furfural char storage silo with a sealing device through a conveying device. S2: Weigh the furfural char, anthracite, and bituminous coal and load them into the raw coal conveyor belt in the pulverizing workshop in the order of anthracite at the bottom, furfural char in the middle, and bituminous coal at the top. S3: The furfural charcoal and coal powder are fed into a medium-speed mill via a conveyor belt, where they are mixed, dried, and pulverized to obtain a mixed powder with a particle size of less than 0.074 mm accounting for 40% to 95%, a moisture content of less than 2.8%, and a bulk density of 0.55 g / cm³. 3 -0.76g / cm 3 ; S4: The mixed powder is injected into the blast furnace tuyere through the pulverized coal silo, injection tank, pulverized coal distributor and injection gun, and burns in contact with high temperature oxygen-enriched air in the blast furnace tuyere swirling zone, providing heat and reducing agent for blast furnace smelting.

2. The blast furnace pulverized coal injection process for steel enterprises utilizing furfural carbon according to claim 1, characterized in that: In step S1, the ash content of the furfural char dry basis is less than 15%, and the furfural char is stored in the storage silo for no more than 15 days.

3. The blast furnace pulverized coal injection process for steel enterprises utilizing furfural carbon according to claim 1, characterized in that: In step S2, the furfural char, anthracite and bituminous coal are loaded into the storage bin using a material handling machine, weighed by a belt scale and then transported to the raw coal conveyor belt in the pulverizing workshop. The dry basis mass ratio of the furfural char, anthracite and bituminous coal is in the range of 1%-30%, 45%-60% and 10%-40%, respectively.

4. The blast furnace pulverized coal injection process for steel enterprises utilizing furfural carbon according to claim 1, characterized in that: In step S3, the inlet flue gas temperature of the medium-speed mill is 250-350℃, the oxygen content is 3%-10%, and the flue gas volume is 1000-2000 m³ / h. 3 / Mixed powder.

5. The blast furnace pulverized coal injection process for steel enterprises utilizing furfural carbon according to claim 1, characterized in that: In step S3, the calorific value of the mixed powder is greater than 25000kJ / kg, the ignition point is greater than 300℃, and the return flame length in the long-tube pulverized coal explosiveness test is less than 80mm.

6. The blast furnace pulverized coal injection process for steel enterprises utilizing furfural carbon according to claim 1, characterized in that: In step S4, the oxygen content in the pulverized coal silo is less than 5%, the storage time of the mixed powder in the pulverized coal silo does not exceed 12 hours, and the pulverized coal conveying gas in the injection tank is high-pressure nitrogen.

7. The blast furnace pulverized coal injection process for steel enterprises utilizing furfural carbon according to claim 1, characterized in that: In step S4, the mixed powder is injected at a rate of 150-200 kg / t of molten iron at the blast furnace tuyeres, the oxygen-enriched air temperature is 1250-1350℃, the oxygen content in the air is 3%-10%, and the air volume is 5000-10000 m³ / t. 3 / t mixed powder.

8. The blast furnace pulverized coal injection process for steel enterprises utilizing furfural carbon according to claim 1, characterized in that: In step S4, the combustion rate of the mixed powder in the blast furnace tuyeres is greater than 60%, providing more than 11,000 kJ / kg of heat to the blast furnace. The reducing agent composition generated by combustion in the blast furnace tuyeres is in the range of CO: 30%-50%, H2: 5%-15%, N2: 40%-60%, and the reducing agent temperature is 2000℃-2300℃.

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