Blast furnace coal injection combustion improver and its preparation method and use method

Abstract

The application relates to the technical field of metallurgy, in particular to a blast furnace coal injection combustion improver and a preparation method and use method thereof. The method comprises the following steps: loading and sealing biomass with a first set particle size, iron-containing minerals with a second set particle size and water to obtain a mixture; wherein the mixing ratio of the biomass and the iron-containing minerals is controlled, and the mixing ratio of the mixture of the biomass and the iron-containing minerals and the water is controlled; the mixture is heated, and the process parameters of the heating are controlled, and then cooling is carried out to obtain carbonized liquid; the carbonized liquid is subjected to staged dewatering treatment to obtain the blast furnace coal injection combustion improver. The blast furnace coal injection combustion improver improves the combustion rate of the injected pulverized coal before the blast furnace tuyere to more than 70%, so that the utilization rate of the pulverized coal in the blast furnace is more than 98%.

Description

Technical Field

[0001] This application relates to the field of metallurgical technology, and in particular to a blast furnace pulverized coal combustion aid and its preparation and application methods. Background Technology

[0002] As a highly material and energy-intensive industry, steel production consumes a large amount of raw materials and fuels, and also generates significant amounts of pollutants and carbon dioxide emissions. Pulverized coal injection technology for blast furnaces is currently the most important technical means to improve the energy structure of ironmaking, optimize blast furnace production, and promote energy conservation and emission reduction in the ironmaking process.

[0003] Currently, the proportion of pulverized coal injected into advanced blast furnaces at home and abroad exceeds 150 kg / tHM. With the increase of the pulverized coal injection ratio, the combustion efficiency of pulverized coal in front of the blast furnace tuyeres has become the key factor limiting the further increase of the pulverized coal injection ratio and the reduction of the coke ratio. Summary of the Invention

[0004] This application provides a blast furnace pulverized coal combustion aid and its preparation and application methods to solve the technical problem of low combustion efficiency of existing pulverized coal in front of the blast furnace tuyeres.

[0005] In a first aspect, this application provides a method for preparing a blast furnace pulverized coal combustion aid, the method comprising:

[0006] The biomass having a first predetermined particle size, iron-containing minerals having a second predetermined particle size, and water are loaded and sealed to obtain a mixture; wherein the ratio of the biomass and the iron-containing minerals, and the ratio of the mixture of the biomass and the iron-containing minerals to the water are controlled.

[0007] The mixture is heated, and the heating process parameters are controlled, followed by cooling to obtain a carbonization liquid;

[0008] The carbonized liquid is dehydrated in stages to obtain a blast furnace pulverized coal combustion aid.

[0009] Optionally, the ratio of the biomass to the iron-containing mineral is 1:0.5-3; and / or,

[0010] The ratio of the mixture of biomass and iron-containing minerals to water is 1:1-3.

[0011] Optionally, the first set particle size is <40mm; and or,

[0012] The second set particle size includes: the iron-containing mineral with a particle size <0.074 mm, and the particle size is...

[0013] The content of the iron-bearing mineral with a diameter of <0.074 mm is >80%.

[0014] Optionally, the biomass includes at least one of the following: corn stalks, wheat stalks, soybean stalks, rice stalks, waste wood; and / or,

[0015] The iron-bearing minerals include at least one of the following: hematite, magnetite, limonite, and vanadium-titanium magnetite.

[0016] Optionally, the heating process parameters include: heating time and heating temperature; wherein,

[0017] The heating time is 20-120 minutes, and the heating temperature is 180-340℃.

[0018] Optionally, the step of performing a staged dehydration treatment on the carbonization liquid to obtain a blast furnace pulverized coal injection combustion aid includes:

[0019] The carbonization liquid is subjected to a first dehydration treatment by pressure filtration to give the carbonization liquid a first water content;

[0020] The carbonized liquid, after the first dehydration, is subjected to a second dehydration treatment by heating to give the carbonized liquid a second water content; wherein...

[0021] The first moisture content is <40%, and the second moisture content is <8%.

[0022] Secondly, this application provides a blast furnace pulverized coal combustion aid, which is prepared by the method described in any embodiment of the first aspect.

[0023] Thirdly, this application provides a method for using a blast furnace pulverized coal combustion aid, the method comprising:

[0024] The blast furnace pulverized coal combustion aid described in the second aspect is pulverized with blast furnace pulverized coal, and the ratio of the pulverized coal combustion aid to the blast furnace pulverized coal is controlled to obtain a mixed powder.

[0025] The mixed powder is burned in the blast furnace tuyeres, and the process parameters of the blast furnace tuyeres combustion are controlled.

[0026] Optionally, the ratio of the pulverized coal combustion aid to the pulverized coal injected into the blast furnace is 0.5%-10%:1.

[0027] Optionally, the process parameters for combustion at the blast furnace tuyeres include: hot blast temperature, oxygen enrichment rate, blast humidity, and theoretical combustion temperature in the tuyeres swirl zone; wherein,

[0028] The hot air temperature is >1100℃, the oxygen enrichment rate is >2%, the blower humidity is <2%, and the theoretical combustion temperature of the air outlet swirl zone is 2000℃~2300℃.

[0029] The technical solutions provided in this application have the following advantages compared with the prior art:

[0030] The method for preparing the blast furnace pulverized coal combustion aid provided in this application uses carbon-neutral renewable biomass resources and iron concentrate powder commonly found in steel enterprises as raw materials. It utilizes hydrothermal synthesis technology to prepare a high specific surface area and high activity pulverized coal combustion aid. This method lowers the ignition point of pulverized coal injected into the blast furnace and increases its combustion rate before the tuyeres. This facilitates high pulverized coal injection ratio production in blast furnace smelting, reduces the coke ratio in blast furnace smelting, and improves the combustion efficiency of pulverized coal before the tuyeres, thereby achieving low-cost and high-efficiency smelting and enhancing the market competitiveness and profitability of enterprise products. This blast furnace pulverized coal combustion aid increases the combustion rate of pulverized coal before the tuyeres by more than 70%, resulting in a pulverized coal utilization rate of over 98% within the blast furnace. Attached Figure Description

[0031] The accompanying drawings, which are incorporated in and form part of this specification, illustrate embodiments consistent with this application and, together with the description, serve to explain the principles of this application.

[0032] To more clearly illustrate the technical solutions in the embodiments of this application or the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, for those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0033] Figure 1 This is a schematic flowchart illustrating a method for preparing a blast furnace pulverized coal combustion aid, as provided in an embodiment of this application. Detailed Implementation

[0034] To make the objectives, technical solutions, and advantages of the embodiments of this application clearer, the technical solutions of the embodiments of this application will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of this application, not all embodiments. Based on the embodiments of this application, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of this application.

[0035] Various embodiments of this application may exist in the form of a range; it should be understood that the description in the form of a range is merely for convenience and brevity and should not be construed as a hard limitation on the scope of this application; therefore, it should be considered that the range description has specifically disclosed all possible sub-ranges and single numerical values ​​within that range. For example, it should be considered that the range description from 1 to 6 has specifically disclosed sub-ranges such as from 1 to 3, from 1 to 4, from 1 to 5, from 2 to 4, from 2 to 6, from 3 to 6, etc., and single numbers within the range, such as 1, 2, 3, 4, 5, and 6, regardless of the range. Furthermore, whenever a numerical range is referred to herein, it means including any referenced number (fraction or integer) within the referred range.

[0036] In this application, unless otherwise stated, directional terms such as "upper" and "lower" specifically refer to the drawing directions in the accompanying drawings. Furthermore, in the description of this application, terms such as "comprising" and "including" mean "including but not limited to." In this document, relational terms such as "first" and "second" are used merely to distinguish one entity or operation from another entity or operation, and do not necessarily require or imply any such actual relationship or order between these entities or operations. In this document, "and / or" describes the relationship between related objects, indicating that three relationships can exist; for example, A and / or B can represent: A alone, A and B simultaneously, or B alone. A and B can be singular or plural. In this document, "at least one" means one or more, and "more than one" means two or more. "At least one," "at least one of the following," or similar expressions refer to any combination of these items, including any combination of single or plural items. For example, "at least one of a, b, or c" or "at least one of a, b, and c" can both mean: a, b, c, ab (i.e., a and b), ac, bc, or abc, where a, b, and c can be a single or multiple.

[0037] Unless otherwise specified, all raw materials, reagents, instruments and equipment used in this application can be purchased from the market or prepared by existing methods.

[0038] Firstly, this application provides a method for preparing a blast furnace pulverized coal combustion aid; please refer to [link to relevant documentation]. Figure 1 The method includes:

[0039] S1. The biomass having a first set particle size, the iron-containing mineral having a second set particle size, and water are loaded and sealed to obtain a mixture; wherein, the ratio of the biomass and the iron-containing mineral is controlled, and the ratio of the mixture of the biomass and the iron-containing mineral to the water is controlled.

[0040] In some embodiments, the ratio of the biomass to the iron-containing mineral is 1:0.5-3; and or, the ratio of the mixture of the biomass and the iron-containing mineral to the water is 1:1-3.

[0041] In the embodiments of this application, the positive effect of controlling the ratio of biomass to iron-containing minerals to be 1:0.5-3 is that the obtained combustion aid has a better catalytic effect. If the content of iron-containing minerals is too high, it will reduce the adhesion effect of nano-carbon particles on the surface of iron-containing mineral particles during the biomass hydrothermal process to a certain extent, thus reducing the catalytic effect of the combustion aid; if the content of iron-containing minerals is too low, it will cause nano-carbon particles to crowd and aggregate on the surface of iron-containing mineral particles during the biomass hydrothermal process, thus reducing the catalytic effect of the combustion aid. Specifically, the ratio of biomass to iron-containing minerals can be 1:0.5, 1:2, 1:3, etc.

[0042] The positive effects of controlling the ratio of biomass and iron-containing minerals to water at 1:1-3 include reducing energy consumption in the reaction system and improving the adhesion of nano-carbon particles to the surface of carbon-containing mineral particles during the hydrothermal carbonization of biomass. If the water content is too high, it will inhibit the re-condensation reaction of organic matter entering the liquid phase of the biomass at low temperature, thus hindering the formation of nano-carbon particles and negatively impacting the catalytic effect of the combustion aid. Conversely, if the water content is too low, it will affect the uniformity of the material reaction during hydrothermal carbonization, thereby affecting the adhesion of nano-carbon particles to the surface of iron-containing mineral particles and reducing the catalytic effect of the combustion aid. Specifically, the ratio of biomass and iron-containing minerals to water can be 1:1, 1:2, 1:3, etc.

[0043] In some embodiments, the first set particle size is <40 mm; and or, the second set particle size includes:

[0044] The iron-bearing mineral has a particle size of <0.074 mm, and the content of the iron-bearing mineral with a particle size of <0.074 mm is >80%.

[0045] "First set particle size" refers to the particle size of biomass, and "Second set particle size" refers to the particle size of iron-containing minerals.

[0046] In this embodiment, controlling the particle size of biomass to <40mm has the following positive effects: it facilitates the loading of biomass raw materials into the reaction vessel. Controlling the particle size of iron-containing minerals to <0.074mm, and ensuring that the content of iron-containing minerals with a particle size of <0.074mm is >80%, has the following positive effects: it increases the specific surface area of ​​the iron-containing minerals and improves the adhesion of nano-carbon particles to the surface of the iron-containing mineral particles. Biomass and iron-containing minerals with the above-mentioned particle size are obtained through pulverization.

[0047] In some embodiments, the biomass includes at least one of the following: corn stalks, wheat stalks, soybean stalks, rice stalks, and waste wood; and / or, the iron-bearing mineral includes at least one of the following: hematite, magnetite, limonite, and vanadium-titanium magnetite.

[0048] In the embodiments of this application, the positive effects of selecting corn stalks, wheat stalks, soybean stalks, rice stalks, and waste wood as biomass are as follows: these biomass raw materials are characterized by wide availability, renewability, high yield, and low price. The positive effects of selecting hematite, magnetite, limonite, and vanadium-titanium magnetite as iron-bearing minerals are as follows: these are commonly used raw materials in blast furnace ironmaking production, characterized by low price, convenient access, and good performance.

[0049] S2. The mixture is heated, and the heating process parameters are controlled, and then cooled to obtain a carbonization liquid;

[0050] In some embodiments, the heating process parameters include: heating time and heating temperature; wherein,

[0051] The heating time is 20-120 minutes, and the heating temperature is 180-340℃.

[0052] In the embodiments of this application, the positive effects of controlling the heating time to 20-120 min and the heating temperature to 180-340℃ are: ensuring efficient carbonization of the reactants under low energy consumption conditions, reducing equipment investment costs, lowering the manufacturing cost of the combustion aid, and improving the catalytic effect of the combustion aid. If the heating temperature is too high or the heating time is too long, it will cause excessive energy consumption in the reaction system to a certain extent, requiring higher pressure resistance of the equipment, thus increasing the manufacturing cost of the combustion aid; if the heating temperature is too low or the heating time is too short, it will cause the hydrothermal carbonization reaction to be difficult to occur quickly, resulting in poor nano-carbon generation and adsorption effects, and weakening the catalytic effect of the prepared combustion aid. Specifically, the heating time can be 20 min, 60 min, 120 min, etc., and the heating temperature can be 180℃, 250℃, 340℃, etc.

[0053] S3. The carbonized liquid is dehydrated in stages to obtain a blast furnace pulverized coal combustion aid.

[0054] In some embodiments, the step of performing a staged dehydration treatment on the carbonization liquid to obtain a blast furnace pulverized coal combustion aid includes:

[0055] The carbonization liquid is subjected to a first dehydration treatment by pressure filtration to give the carbonization liquid a first water content;

[0056] The carbonized liquid, after the first dehydration, is subjected to a second dehydration treatment by heating to give the carbonized liquid a second water content; wherein...

[0057] The first moisture content is <40%, and the second moisture content is <8%.

[0058] In this embodiment, the positive effects of staged dehydration of the carbonized liquid include: reducing the impact of the combustion aid on the coal powder output during the coal mill pulverization process. "First moisture content" refers to the moisture content of the carbonized liquid after pressure filtration. A moisture content of <40% in the filtered carbonized liquid has the positive effect of reducing the impact of harmful elements dissolved in wastewater on the effectiveness of the combustion aid. If the moisture content of the filtered carbonized liquid is too high, it will increase the content of harmful elements (K, Na, P, S, Cl) in the combustion aid to some extent. Specifically, the moisture content of the filtered carbonized liquid can be 39%, 37%, 35%, etc. "Second moisture content" refers to the moisture content of the heated carbonized liquid. Controlling the moisture content of the heated carbonized liquid to <8% has the positive effect of reducing the impact of the combustion aid on the coal powder output during the coal mill pulverization process. If the moisture content of the heated carbonized liquid is too high, it will reduce the output of the coal mill to some extent. Specifically, the water content of the heated carbonization liquid can be 7%, 6%, 5%, etc.

[0059] Secondly, this application provides a blast furnace pulverized coal combustion aid, which is prepared by the method described in any embodiment of the first aspect.

[0060] The blast furnace pulverized coal combustion aid is based on the preparation method of the above-mentioned blast furnace pulverized coal combustion aid. The specific steps of the preparation method of the blast furnace pulverized coal combustion aid can be referred to the above embodiments. Since the blast furnace pulverized coal combustion aid adopts some or all of the technical solutions of the above embodiments, it has at least all the beneficial effects brought about by the technical solutions of the above embodiments, which will not be elaborated here.

[0061] Thirdly, this application provides a method for using a blast furnace pulverized coal combustion aid, the method comprising:

[0062] S4. The blast furnace pulverized coal combustion aid described in the second aspect is pulverized with blast furnace pulverized coal, and the ratio of the pulverized coal combustion aid to the blast furnace pulverized coal is controlled to obtain a mixed powder.

[0063] In some embodiments, the ratio of the pulverized coal combustion aid to the pulverized coal injected into the blast furnace is 0.5%-10%:1.

[0064] In the embodiments of this application, the positive effects of controlling the ratio of pulverized coal injection aid to pulverized coal injected into the blast furnace at 0.5%-10%:1 are as follows: without changing the existing pulverized coal injection process in the blast furnace, it can promote the combustion effect of pulverized coal before the tuyeres, improve the utilization of pulverized coal injected into the blast furnace, and reduce the cost of pulverized coal injection. If the content of the pulverized coal injection aid is too high, it will increase the injection cost to a certain extent; if the content of the pulverized coal injection aid is too low, it will not improve the combustion effect of pulverized coal before the tuyeres to a certain extent. Specifically, the ratio of pulverized coal injection aid to pulverized coal injected into the blast furnace can be 0.5%:1, 5%:1, 10%:1, etc.

[0065] The pulverized coal used for blast furnace injection includes at least one of the following: bituminous coal, lean coal, anthracite, semi-coke, and semi-coke; the proportion of the mixed powder with a particle size of less than 0.074 mm is greater than 60%, and the moisture content is less than 1.6%.

[0066] S5. The mixed powder is burned in the blast furnace tuyeres, and the process parameters of the blast furnace tuyeres combustion are controlled.

[0067] In some embodiments, the process parameters for combustion at the blast furnace tuyeres include: hot blast temperature, oxygen enrichment rate, blast humidity, and theoretical combustion temperature in the tuyeres swirl zone; wherein,

[0068] The hot air temperature is >1100℃, the oxygen enrichment rate is >2%, the blower humidity is <2%, and the theoretical combustion temperature of the air outlet swirl zone is 2000℃~2300℃.

[0069] In the embodiments of this application, the positive effects of controlling the hot blast temperature, oxygen enrichment rate, blast humidity and theoretical combustion temperature of the tuyere swirling zone of the blast furnace combustion are: to improve the combustion efficiency of pulverized coal in front of the tuyere, and to create conditions for further increasing the pulverized coal injection ratio and reducing the coke ratio.

[0070] If the hot blast temperature is too low, it will, to some extent, hinder the combustion-enhancing effect of the combustion-supporting agent on the pulverized coal, reducing the utilization rate of pulverized coal in the blast furnace. Specifically, the hot blast temperature can be 1120℃, 1140℃, etc. If the oxygen enrichment rate is too low, it will, to some extent, reduce the utilization rate of the pulverized coal and inhibit the catalytic effect of the combustion-supporting agent. Specifically, the oxygen enrichment rate can be 3%, 4%, etc. If the blast humidity is too high, it will, to some extent, lower the theoretical combustion temperature before the tuyeres, inhibiting the catalytic effect of the combustion-supporting agent on the pulverized coal combustion process. Specifically, the blast humidity can be 1%, 1.5%, etc. If the theoretical combustion temperature in the tuyeres swirl zone is too high, it will, to some extent, hinder the stability and smooth operation of the blast furnace smelting; if the theoretical combustion temperature in the tuyeres swirl zone is too low, it will, to some extent, inhibit the catalytic effect of the combustion-supporting agent on the pulverized coal combustion process. Specifically, the theoretical combustion temperature in the tuyeres swirl zone can be 2000℃, 2100℃, 2200℃, 2300℃, etc.

[0071] Due to the adoption of the above technical solution, the beneficial effects of this application are as follows:

[0072] (1) It plays a template role in the hydrothermal synthesis of biomass. The prepared combustion aid has the advantages of large specific surface area and high activity, which can improve the combustion efficiency of pulverized coal injection in blast furnace.

[0073] (2) Using biomass waste and iron-containing minerals as raw materials to prepare combustion aids has the advantages of abundant raw material sources, simple preparation process and low product price;

[0074] (3) Biomass is carbon neutral. When it is used to prepare combustion aids, it can not only promote the combustion of pulverized coal, but also reduce the carbon dioxide emissions in the ironmaking process.

[0075] (4) The hydrothermal synthesis process can remove elements such as potassium, sodium, sulfur, chlorine and fluorine from biomass and iron ore powder raw materials that are harmful to blast furnace smelting, which is conducive to the longevity of blast furnace.

[0076] The present application is further illustrated below with reference to specific embodiments. It should be understood that these embodiments are for illustrative purposes only and are not intended to limit the scope of the application. Experimental methods in the following embodiments that do not specify specific conditions are generally determined according to national standards. If there is no corresponding national standard, then general international standards, conventional conditions, or conditions recommended by the manufacturer are followed.

[0077] Example 1

[0078] Take, for example, wheat straw from farms and magnetite concentrate from ironworks as raw materials for the preparation of combustion aids.

[0079] Preparation method of pulverized coal combustion aid for blast furnace:

[0080] (1) The collected wheat straw is passed through a vibrating screen and an iron remover to remove impurities and then fed to a crusher for crushing. The crushed wheat straw has a particle size of less than 40 mm, and the magnetite concentrate from the ironmaking plant has a particle size of less than 0.074 mm, accounting for more than 95%. 100 kg of the crushed wheat straw and 100 kg of magnetite concentrate are weighed and loaded into a 1m... 3 Inside the electrically heated high-pressure reactor, 500 kg of water was added simultaneously. After the loading was completed, the reactor was sealed, and nitrogen gas at 2 MPa was introduced to test the reactor's sealing performance. Once it was confirmed that the reactor was airtight, the pressure relief valve was opened to release the pressure until atmospheric pressure was reached, at which point the pressure relief valve was closed.

[0081] (2) Turn on the heating switch of the high-pressure reactor to heat the material in the reactor. When the temperature inside the reactor is below 150°C, the heating rate is controlled at 5°C / min. When the temperature exceeds 150°C, the heating rate is 2°C / min. When the temperature inside the reactor reaches 190°C, keep it at that temperature for 60 minutes and then turn off the heating switch to cool it down. When the temperature inside the reactor drops to 50°C, open the pressure relief valve of the reactor to release the gas generated inside the reactor, and then open the discharge valve to discharge the carbonized liquid from the reactor.

[0082] (3) The cooled carbonization liquid was pumped to a plate and frame filter press for dewatering. The moisture content of the high-moisture biomass-based iron-based blast furnace pulverized coal combustion aid obtained after filtration was determined to be 36.8%. To further reduce the moisture content of the biomass-based iron-based blast furnace pulverized coal combustion aid, it was transferred to a drying oven for heating and drying at 105℃ for 8 hours. The moisture content of the dried biomass-based iron-based blast furnace pulverized coal combustion aid was 5.6%. Method of using blast furnace pulverized coal combustion aid:

[0083] The pulverized coal injected into the blast furnace is a mixture of anthracite, bituminous coal, and semi-coke in a specific ratio of 3:5:2. A biomass-based iron-based pulverized coal combustion aid is added to the pulverized coal at a mass percentage of 2.5%. The pulverized coal with the added combustion aid is then pulverized using a medium-speed mill, ensuring thorough mixing of the pulverized coal and combustion aid during the pulverization process. After pulverization, 80% of the pulverized coal has a particle size less than 0.074 mm and a moisture content of 1.35%. The pulverized coal is then injected into the blast furnace tuyeres for combustion. The blast furnace hot blast temperature is 1150℃, the oxygen enrichment rate is 3.0%, the blast humidity is 1.5%, the theoretical combustion temperature in the tuyeres vortex zone is 2180℃, and the injection rate is 145 kg / tHM (ton of iron). The combustion rate of the pulverized coal before the blast furnace tuyeres is 75%, and the utilization rate of the pulverized coal within the furnace is 98.8%.

[0084] Compared to when this blast furnace pulverized coal combustion aid is not added, the combustion rate increases by 6% and the utilization rate increases by 0.5%.

[0085] Example 2

[0086] Take, for example, corn stalks from farms and magnetite concentrate from ironworks as raw materials for the preparation of combustion aids.

[0087] Preparation method of pulverized coal combustion aid for blast furnace:

[0088] (1) After removing impurities from the collected corn stalks through a vibrating screen and an iron remover, the stalks are fed to a crusher for crushing. The crushed corn stalks have a particle size of less than 40 mm, and the magnetite concentrate from the ironworks has a particle size of less than 0.074 mm, accounting for more than 90%. 1000 kg of the crushed corn stalks and 500 kg of the magnetite concentrate are weighed and loaded into a 10m... 3 The heat transfer oil is used to heat the high-pressure reactor, and 4500 kg of water is added to the reactor at the same time. After the loading is completed, the reactor is sealed, and nitrogen gas at 2 MPa is introduced to test the reactor's sealing performance. After confirming that the reactor is airtight, the pressure relief valve is opened to release the pressure in the reactor until it reaches atmospheric pressure, and then the pressure relief valve is closed.

[0089] (2) Turn on the heating switch of the high-pressure reactor to heat the material in the reactor. When the temperature inside the reactor is below 180°C, the heating rate is controlled at 4°C / min. When the temperature exceeds 180°C, the heating rate is 2°C / min. When the temperature inside the reactor reaches 210°C, keep it at that temperature for 30 minutes and then turn off the heating switch to cool it down. When the temperature inside the reactor drops to 50°C, open the pressure relief valve of the reactor to release the gas generated inside the reactor, and then open the discharge valve to discharge the carbonized liquid from the reactor.

[0090] (3) The cooled carbonization liquid was pumped to a plate and frame filter press for dewatering by a mud pump. The moisture content of the high-moisture biomass-based iron-based blast furnace pulverized coal combustion aid obtained after filtration was determined to be 35.1%. In order to further reduce the moisture content of the biomass-based iron-based blast furnace pulverized coal combustion aid, the high-moisture biomass-based iron-based blast furnace pulverized coal combustion aid was transferred to a cylindrical dryer for heating and drying. The heating temperature was 150℃ and the drying time was 1h. The moisture content of the dried biomass-based iron-based blast furnace pulverized coal combustion aid was 3.5%.

[0091] Instructions for using pulverized coal combustion aid in blast furnaces:

[0092] The pulverized coal injected into the blast furnace is a mixture of anthracite and bituminous coal in a specific ratio of 6:4. A biomass-based iron-based pulverized coal combustion aid is added to the pulverized coal at a mass percentage of 3.2%. The pulverized coal, after the addition of the combustion aid, is pulverized using a medium-speed mill. During the pulverization process, the pulverized coal and combustion aid are thoroughly mixed. After pulverization, 70% of the pulverized coal has a particle size less than 0.074 mm, and the moisture content is 1.46%. The pulverized coal enters the blast furnace tuyeres for combustion via the injection system. The blast furnace hot blast temperature is 1200℃, the oxygen enrichment rate is 2.8%, the blast humidity is 1.3%, the theoretical combustion temperature in the tuyeres vortex zone is 2150℃, and the injection rate is 175 kg / tHM (ton of iron). The combustion rate of the pulverized coal before the blast furnace tuyeres is 73%, and the utilization rate of the pulverized coal within the furnace is 98.5%.

[0093] Compared to when this blast furnace pulverized coal combustion aid is not added, the combustion rate increases by 7% and the utilization rate increases by 0.8%.

[0094] Example 3

[0095] Take, for example, waste wood from furniture factories and hematite from iron smelters as raw materials for the preparation of combustion aids.

[0096] Preparation method of pulverized coal combustion aid for blast furnace:

[0097] (1) The collected waste wood is passed through a vibrating screen and an iron remover to remove impurities before being fed to a crusher for crushing. The crushed elm straw has a particle size of less than 30 mm. The hematite from the ironworks is crushed by a ball mill, and the crushed particle size is less than 0.074 mm, accounting for more than 95%. 500 kg of the crushed waste wood and 700 kg of magnetite concentrate are weighed and loaded into a 5m... 3 The heat transfer oil is used to heat the high-pressure reactor, and 2800 kg of water is added to the reactor at the same time. After the loading is completed, the reactor is sealed, and nitrogen gas at 2 MPa is introduced to test the reactor's sealing performance. After confirming that the reactor is airtight, the pressure relief valve is opened to release the pressure in the reactor until it reaches atmospheric pressure, and then the pressure relief valve is closed.

[0098] (2) Turn on the heating switch of the high-pressure reactor to heat the material in the reactor. When the temperature inside the reactor is below 200°C, the heating rate is controlled at 4°C / min. When the temperature exceeds 200°C, the heating rate is 2°C / min. When the temperature inside the reactor reaches 240°C, keep it at that temperature for 30 minutes and then turn off the heating switch to cool it down. When the temperature inside the reactor drops to 50°C, open the pressure relief valve of the reactor to release the gas generated inside the reactor, and then open the discharge valve to discharge the carbonized liquid from the reactor.

[0099] (3) The cooled carbonization liquid was pumped to a plate and frame filter press for dewatering. The moisture content of the high-moisture biomass-based iron-based blast furnace pulverized coal combustion aid obtained after filtration was determined to be 30.5%. In order to further reduce the moisture content of the biomass-based iron-based blast furnace pulverized coal combustion aid, the high-moisture biomass-based iron-based blast furnace pulverized coal combustion aid was transferred to a cylindrical dryer for heating and drying. The heating temperature was 175℃ and the drying time was 1h. The moisture content of the dried biomass-based iron-based blast furnace pulverized coal combustion aid was 1.8%.

[0100] Instructions for using pulverized coal combustion aid in blast furnaces:

[0101] The pulverized coal injected into the blast furnace is a mixture of anthracite and bituminous coal in a 5:5 ratio. A biomass-based iron-based pulverized coal combustion aid is added to the pulverized coal at a mass percentage of 2.6%. The pulverized coal, after the addition of the combustion aid, is pulverized using a medium-speed mill. During the pulverization process, the pulverized coal and combustion aid are thoroughly mixed. After pulverization, 75% of the pulverized coal has a particle size less than 0.074 mm and a moisture content of 1.38%. The pulverized coal enters the blast furnace tuyeres for combustion via the injection system. The blast furnace hot blast temperature is 1160℃, the oxygen enrichment rate is 4.6%, the blast humidity is 1.4%, the theoretical combustion temperature in the tuyeres vortex zone is 2200℃, and the injection rate is 160 kg / tHM (ton of iron). The combustion rate of the pulverized coal before the blast furnace tuyeres is 77%, and the utilization rate of the pulverized coal within the furnace is 98.9%.

[0102] Compared to when this blast furnace pulverized coal combustion aid is not added, the combustion rate increases by 7.3% and the utilization rate increases by 0.8%.

[0103] Example 4

[0104] Taking waste wood from furniture factories and vanadium-titanium magnetite from iron smelters as raw materials for the preparation of combustion aids as an example.

[0105] Preparation method of pulverized coal combustion aid for blast furnace:

[0106] (1) The collected waste wood is passed through a vibrating screen and an iron remover to remove impurities before being fed to a crusher for crushing. The crushed elm straw has a particle size of less than 30 mm, and the vanadium-titanium magnetite concentrate from the ironmaking plant has a particle size of less than 0.074 mm, accounting for more than 96%. 1200 kg of the crushed waste wood and 300 kg of the magnetite concentrate are weighed and loaded into an 8m... 3 The heat transfer oil is used to heat the high-pressure reactor, and 4500 kg of water is added to the reactor at the same time. After the loading is completed, the reactor is sealed, and nitrogen gas at 2 MPa is introduced to test the reactor's sealing performance. After confirming that the reactor is airtight, the pressure relief valve is opened to release the pressure in the reactor until it reaches atmospheric pressure, and then the pressure relief valve is closed.

[0107] (2) Turn on the heating switch of the high-pressure reactor to heat the material in the reactor. When the temperature inside the reactor is below 180°C, the heating rate is controlled at 4°C / min. When the temperature exceeds 180°C, the heating rate is 2°C / min. When the temperature inside the reactor reaches 230°C, keep it at that temperature for 50 minutes and then turn off the heating switch to cool it down. When the temperature inside the reactor drops to 50°C, open the pressure relief valve of the reactor to release the gas generated inside the reactor, and then open the discharge valve to discharge the carbonized liquid from the reactor.

[0108] (3) The cooled carbonization liquid was pumped to a plate and frame filter press for dewatering. The moisture content of the high-moisture biomass-based iron-based blast furnace pulverized coal combustion aid obtained after filtration was determined to be 33.2%. In order to further reduce the moisture content of the biomass-based iron-based blast furnace pulverized coal combustion aid, the high-moisture biomass-based iron-based blast furnace pulverized coal combustion aid was transferred to a cylindrical dryer for heating and drying. The heating temperature was 135℃ and the drying time was 2h. The moisture content of the dried biomass-based iron-based blast furnace pulverized coal combustion aid was 2.9%.

[0109] Instructions for using pulverized coal combustion aid in blast furnaces:

[0110] The pulverized coal injected into the blast furnace is a mixture of anthracite, bituminous coal, and semi-coke in a specific ratio of 4:3:3. A biomass-based iron-based pulverized coal combustion aid is added to the pulverized coal at a mass percentage of 6.8%. The pulverized coal with the added combustion aid is then pulverized using a medium-speed mill, ensuring thorough mixing of the pulverized coal and combustion aid during the pulverization process. After pulverization, 80% of the pulverized coal has a particle size less than 0.074 mm, and a moisture content of 1.26%. The pulverized coal is then injected into the blast furnace tuyeres for combustion. The blast furnace hot blast temperature is 1160℃, the oxygen enrichment rate is 4.6%, the blast humidity is 1.9%, the theoretical combustion temperature in the tuyeres vortex zone is 2210℃, and the injection rate is 150 kg / tHM (ton of iron). The combustion rate of the pulverized coal before the blast furnace tuyeres is 73%, and the utilization rate of the pulverized coal within the furnace is 98.5%.

[0111] Compared to when this blast furnace pulverized coal combustion aid is not added, the combustion rate increases by 5.3% and the utilization rate increases by 0.5%.

[0112] The above description is merely a specific embodiment of this application, enabling those skilled in the art to understand or implement this application. Various modifications to these embodiments will be readily apparent to those skilled in the art, and the general principles defined herein may be implemented in other embodiments without departing from the spirit or scope of this application. Therefore, this application is not to be limited to the embodiments shown herein, but is to be accorded the widest scope consistent with the principles and novel features claimed herein.

Claims

1. A method for preparing a blast furnace pulverized coal combustion aid, characterized in that, The method includes: Biomass with a first set particle size, iron-containing minerals with a second set particle size, and water are loaded and sealed to obtain a mixture; wherein the mass ratio of the biomass and the iron-containing minerals is controlled to be 1:0.5-3, and the mass ratio of the mixture of biomass and the iron-containing minerals to the water is controlled to be 1:1-3. The mixture is heated, and the heating process parameters are controlled, followed by cooling to obtain a carbonization liquid; The carbonized liquid is dehydrated in stages to obtain a blast furnace pulverized coal combustion aid.

2. The preparation method according to claim 1, characterized in that, The first set particle size is <40mm; and / or, The second set particle size includes: the iron-containing mineral with a particle size <0.074 mm, and the particle size is... The content of the iron-bearing mineral with a diameter of <0.074 mm is >80%.

3. The preparation method according to claim 1, characterized in that, The biomass includes at least one of the following: corn stalks, wheat stalks, soybean stalks, rice stalks, waste wood; and / or, The iron-bearing minerals include at least one of the following: hematite, magnetite, limonite, and vanadium-titanium magnetite.

4. The preparation method according to claim 1, characterized in that, The heating process parameters include: heating time and heating temperature; wherein, The heating time is 20-120 minutes, and the heating temperature is 180-340℃.

5. The preparation method according to claim 1, characterized in that, The step of dehydrating the carbonization liquid in stages to obtain a blast furnace pulverized coal combustion aid includes: The carbonization liquid is subjected to a first dehydration treatment by pressure filtration to give the carbonization liquid a first water content; The carbonized liquid, after the first dehydration, is subjected to a second dehydration treatment by heating to give the carbonized liquid a second water content; wherein... The first moisture content is <40%, and the second moisture content is <8%.

6. A blast furnace pulverized coal combustion aid, characterized in that, The blast furnace pulverized coal combustion aid is prepared by the method described in any one of claims 1-5.

7. A method for using a blast furnace pulverized coal combustion aid, characterized in that, The method of use includes: The pulverized coal injection aid described in claim 6 is pulverized with pulverized coal injected into the blast furnace, and the mass ratio of the pulverized coal injection aid to the pulverized coal is controlled to obtain a mixed powder. The mixed powder is burned in the blast furnace tuyeres, and the process parameters of the blast furnace tuyeres combustion are controlled.

8. The method of use according to claim 7, characterized in that, The mass ratio of the pulverized coal combustion aid to the pulverized coal injected into the blast furnace is 0.5%-10%:

1.

9. The method of use according to claim 7, characterized in that, The process parameters for combustion at the blast furnace tuyeres include: hot blast temperature, oxygen enrichment rate, blast humidity, and theoretical combustion temperature in the tuyeres swirl zone; among which... The hot air temperature is >1100 ℃, the oxygen enrichment rate is >2%, the blower humidity is <2%, and the theoretical combustion temperature of the air outlet swirl zone is 2000 ℃~2300 ℃.

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