CN115652017A - Converter high-cold-material-ratio low-carbon smelting device and smelting method - Google Patents
Converter high-cold-material-ratio low-carbon smelting device and smelting method Download PDFInfo
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Abstract
The invention discloses a converter high-cold-material-ratio low-carbon smelting device and a smelting method, and belongs to the technical field of converter steelmaking. The converter high-cold-material-ratio low-carbon smelting device comprises a converter main body, a gas source, a biomass carbon powder bin, a lime powder bin, a biomass carbon powder injection tank, a lime powder injection tank, a first injector, a second injector, a rotary joint, a distributor, a bottom blowing gun and an oxygen lance. The smelting method comprises four stages of a preheating stage, a melting-down stage and an air blowing stage: the device has simple structure and smelting method, the close matching of the preheating stage, the melting-down stage and the air blowing stage can effectively reduce the FeO content at the end point of the slag, improve the metal yield, is very beneficial to the low-carbon smelting of the converter with high cold charge ratio, and also reduces the lime consumption and CO 2 Discharge and benefit to industryLarge-scale production and popularization.
Description
Technical Field
The invention belongs to the technical field of converter steelmaking, and relates to a converter high-cold-material-ratio low-carbon smelting device and a converter high-cold-material-ratio low-carbon smelting method.
Background
In the traditional converter steelmaking, molten iron is used as a main raw material, a small amount of scrap steel is added, and the proportion of the scrap steel is usually lower than 20 percent due to insufficient heat. For converter steelmaking, increasing the scrap ratio can reduce CO 2 And (5) discharging.
According to the measurement and calculation, when the proportion of the scrap steel in the converter steelmaking is increased by 10 percent (namely the proportion of the molten iron is reduced by 10 percent), CO in the smelting of one ton of steel 2 The total emissions can be reduced by about 6%.
In the prior art, a hydrogen-based direct reduction iron-making process is developed vigorously and replaces a blast furnace iron-making process step by step, and Direct Reduced Iron (DRI) serving as a low-carbon furnace charge is widely applied. With the increase of the accumulated amount of the social waste steel and the popularization of the hydrogen-based direct reduction iron-making process, smelting by replacing blast furnace molten iron with low-carbon furnace burden (waste steel/DRI) with higher proportion in a converter becomes a necessary choice for high-efficiency low-carbon steel making of the converter.
Compared with the traditional converter steelmaking mode, the smelting characteristics of the converter under the condition of high scrap/DRI (direct reduced iron) charging ratio are greatly changed, the problems of insufficient heat source of a molten pool, slow melting of the scrap/DRI (direct reduced iron), difficult effective impact of top-blown oxygen jet flow on a metal molten pool and the like exist, and the corresponding periodic characteristics of desiliconization, dephosphorization, decarburization and temperature rise of the converter also have problems.
Chinese patent CN109136451A discloses a method for reducing iron loss, which is an important way for increasing the heat of a converter and improving the cold material ratio by adding a carbonaceous heating agent into the converter, so as to increase the surplus heat and increase the adding proportion of waste steel; however, the method has the defects that the adding cost of the carbonaceous exothermic agent is high, the stirring of the molten iron is realized only by the complicated control of the lance position of oxygen top blowing, the stirring of a molten pool is insufficient, and the removal efficiency of impurity elements is not high.
Chinese patent CN112094980A discloses a converter top-bottom composite powder injection efficient smelting system and a smelting method, wherein the system mainly comprises a converter, an oxygen lance, a central powder conveying pipeline, a top-blown powder injection tank, a top-blown gas carrying pipeline, an oxygen lance main gas blowing pipeline, a top gas blowing pipeline, a bottom powder injection element, a distributor, a bottom pipeline, a bottom-blown powder injection tank, a bottom gas blowing pipeline and a buffer tank; obviously, the modes of top-blowing lime powder spraying and low-blowing lime powder spraying cannot solve the technical problems of low post combustion rate in the furnace, insufficient stirring of a molten pool and the like, and the lime consumption reduction effect is general.
Chinese patent CN110144430A discloses a method for improving the early-stage smelting temperature under a bottom blowing powder spraying process, after converter is blown down, nitrogen is used as carrier gas, annular seam cooling protective gas is used as hydrocarbon, a mixture of carbon powder and coal powder is sprayed into the converter through a double-layer sleeve type bottom blowing powder spraying gun, and the early-stage smelting temperature of the converter is improved by utilizing the heat release of the combustion of the carbon powder and the coal powder; although the mode can improve the early-stage temperature of converter smelting, the heat supplementing effect is not obvious for low-carbon smelting with high cooling-material ratio
In conclusion, the converter steelmaking at present generally adopts a top-blown supersonic oxygen jet and bottom-blown small-flow inert gas blowing mode, the secondary combustion rate in the converter is low, the molten pool stirring is insufficient, the gas-slag-gold three-phase reaction is difficult to reach balance, the metallurgical reaction excessively depends on the impact of the top-blown oxygen on the slag-gold molten pool, and an efficient and low-cost heat supplementing means is lacked. Under the condition of high scrap steel/DRI charging ratio, the conventional converter is very easy to have accident furnace conditions of cold furnace, oxygen non-ignition, explosive splashing and the like, and the requirements of safe, efficient and stable production under the condition of new furnace materials are difficult to meet.
Disclosure of Invention
The invention aims to solve the technical problems that no device structure arrangement and smelting method suitable for converter high-cold-material-ratio low-carbon smelting exist in the prior art, and particularly, although some technical schemes improve the converter high-cold-material ratio by improving the smelting temperature, the method for improving the smelting temperature has the technical defects of high cost, low efficiency, influence on molten pool stirring and metallurgical reaction, possibility of excessive foaming of furnace slag and the like.
In order to solve the technical problems, the invention provides the following technical scheme:
a converter high-cold-material-ratio low-carbon smelting device comprises a converter main body, wherein an oxygen lance penetrates through the top of the converter main body, a bottom blowing lance is arranged at the bottom of the converter main body, a distributor is communicated with the bottom blowing lance and is communicated with one end of a rotary joint arranged on one side of the converter main body through a connecting pipeline, and the other end of the rotary joint is respectively communicated with a first ejector and a second ejector;
the first ejector is respectively communicated with an air source and a biomass carbon powder injection tank, and the biomass carbon powder injection tank is communicated with the biomass carbon powder bin;
the second ejector is respectively communicated with a gas source and a lime powder injection tank, and the lime powder injection tank is communicated with the lime powder bin.
Preferably, the bottom blowing gun is of a triple sleeve structure, the main pipeline is a biomass carbon powder and lime powder channel, and the inner layer circular seam and the outer layer circular seam are protective gas channels.
Preferably, the carrier gas of the biomass carbon powder is nitrogen, carbon dioxide, argon or a mixed gas thereof, and the carrier gas of the lime powder is oxygen, carbon dioxide, argon or a mixed gas thereof.
Preferably, in the triple casing structure of the bottom blowing gun, the size of a main pipeline is 20-30mm, the size of an inner layer circular seam is 1-3mm, and the size of an outer layer circular seam is 1-3mm.
Preferably, the biomass charcoal powder comprises corn stalk charcoal powder, rice stalk charcoal powder, cotton stalk charcoal powder, sawdust charcoal powder, wheat stalk charcoal powder and the like.
Preferably, the particle size of the biomass carbon powder in the biomass carbon powder bin is 30-80 meshes, and the particle size of the lime powder in the lime powder bin is 150-250 meshes.
Preferably, the ratio of the particle size of the biomass carbon powder to the particle size of the lime powder is 1.
Preferably, the number of the bottom blowing guns is 2-8 according to the nominal capacity of the converter.
Preferably, the ton of the converter used by the converter high-cold-ratio low-carbon smelting device is 80-300 tons.
Preferably, the number of bottom blowing lances is selected to be 1-2 when the nominal capacity of the converter is 50-100 tons; when the nominal capacity of the converter is 100-200 tons, the number of the bottom blowing guns is 3-6; when the nominal capacity of the converter is 200-300 tons, the number of the bottom blowing guns is selected to be 6-8.
A smelting method of a converter low-carbon smelting device with a high cooling material ratio comprises the following steps:
s1, preheating: after scrap steel/DRI (hydrogen-based directly reduced iron) is added into a converter, bottom blowing oxygen-biomass carbon powder and top blowing oxygen, and performing efficient cold charge preheating by using combustion reaction of the biomass carbon powder and the oxygen;
s2, melting: after the preheating stage of the step S1 is finished, high-temperature and high-carbon molten iron is immediately added into the converter, oxygen-biomass carbon powder blowing from the bottom and oxygen blowing from the top are continued, so that heat can be supplemented, and simultaneously, carbon is added for fluxing, and the melting of steel scrap/DRI (hydrogen-based directly reduced iron) is accelerated;
s3, a melting stage: after 70-80% of scrap steel/DRI (hydrogen-based direct reduced iron) in the melting stage in the step S2 is melted, dynamically adjusting a bottom-blowing gun from bottom-blowing oxygen-biomass carbon powder to bottom-blowing oxygen-lime powder so as to quickly remove impurity elements;
s4, an air blowing stage: and (4) after the melting stage of the step (S3) is blown to TSC (carbon temperature), stopping bottom blowing of lime powder, adjusting the steel tapping to be in a pure gas supply mode in the stage, and enhancing molten pool stirring by high-flow bottom blowing so as to reduce the FeO content at the end point of the slag and improve the metal yield.
Preferably, the converter high cold charge ratio in the smelting method of the converter high cold charge ratio low carbon smelting device is 30-50%.
Preferably, the ratio of scrap/DRI (hydrogen-based direct reduced iron) in step S1 is 1.
Preferably, the steel scrap/DRI (hydrogen-based direct reduced iron) in step S1 is heated to 600-800 ℃ by using the combustion reaction of biomass carbon powder and oxygen for efficient cold charge preheating with a preheating time of 5-6min.
Preferably, when oxygen-biomass carbon powder is blown in the bottom layer in the step S1, oxygen is introduced into the inner layer circular seam, so that the mushroom head generated by the bottom blowing gun head is prevented from blocking the spray gun; introducing nitrogen, argon or natural gas into the outer layer of the circular seam to protect the bottom blowing gun and the furnace bottom brick cup; when the lime powder is blown, nitrogen, argon or natural gas can be introduced into the inner and outer layer circular seams as protective gas.
Preferably, in the step S1, the flow rate of the biomass carbon powder in the central pipe of the single bottom blowing gun is 50-100kg/min; the central tube takes nitrogen, carbon dioxide or the mixture thereof as carrier gas, and the flow rate is 1000-2000Nm 3 H; the oxygen flow rate of the inner circumferential seam is 100-300Nm 3 H; the outer layer circumferential seam takes nitrogen, argon or natural gas as protective gas, and the flow is 100-300Nm 3 /h。
Preferably, the oxygen-biomass carbon powder and the top-blown oxygen are continuously blown from the bottom in the step S2, and the flow rate of the biomass carbon powder in the central tube of the single bottom-blowing gun is 100-200kg/min; the central tube takes nitrogen, carbon dioxide or the mixture thereof as carrier gas, and the flow rate is 1000-2000Nm 3 H; the oxygen flow rate of the inner circumferential seam is 100-300Nm 3 H; the outer layer circumferential seam takes nitrogen, argon or natural gas as protective gas, and the flow rate is 100-300Nm 3 /h。
Preferably, in the step S3, the flow of the lime powder is 100-200kg/min in the central pipe of the single bottom blowing gun; the central tube takes oxygen, carbon dioxide, argon or the mixture thereof as carrier gas, and the flow rate is 1000-2000Nm 3 H; the inner layer circumferential seam takes nitrogen, argon or natural gas as protective gas, and the flow rate is 100-300Nm 3 H; the outer layer circumferential seam takes nitrogen, argon or natural gas as protective gas, and the flow is 100-300Nm 3 /h。
Preferably, the pure gas supply mode in step S4, single bottomThe central tube of the blowing gun only blows argon with the flow rate of 800-1600Nm 3 H; the inner layer circumferential seam takes argon or natural gas as protective gas, and the flow rate is 100-200Nm 3 H; the outer layer circumferential seam takes argon or natural gas as protective gas, the flow rate is 100-200Nm 3 /h。
Preferably, the pressure requirements of gas sources such as nitrogen, argon, oxygen, carbon dioxide, natural gas and the like related to the central tube carrier gas and the inner and outer layer circular seam protective gas are not lower than 1.6MPa; the pressure of the central tube in the converting stage is 1.0-1.3MPa, and the pressure of the protective gas of the inner and outer layer circular seams is 0.8-1.0MPa.
Preferably, the converter cooling material ratio of the smelting method is improved to 30-50%, the consumption of lime per ton of steel is reduced by 5-20kg, and CO per ton of steel billet is reduced 2 The discharge amount is reduced by 50-100kg.
Compared with the prior art, the invention has the following beneficial effects:
in the scheme, the converter high-cold-material-ratio low-carbon smelting device provided by the invention has the advantages that the structural arrangement of the converter main body, the air source, the biomass carbon powder bin, the lime powder bin, the biomass carbon powder injection tank, the lime powder injection tank, the first injector, the second injector, the rotary joint, the distributor, the bottom blowing gun and the oxygen lance can effectively improve the heat supplementing effect, inclusion removal, reaction stability and the like of high scrap steel/DRI (hydrogen-based direct reduced iron) in comparison with the traditional converter smelting, and the converter high-cold-material-ratio low-carbon smelting device is beneficial to industrial large-scale production and popularization.
The invention provides a converter high-cold charge ratio low-carbon smelting method of bottom-sprayed biomass carbon powder, which is characterized in that production is carried out according to a combined blowing converter supporting top-blown oxygen and bottom-blown oxygen-carbon powder-lime powder, after scrap steel/DRI (hydrogen-based directly reduced iron) is added into the converter, firstly bottom-blown oxygen-carbon powder and top-blown oxygen are used for carrying out efficient furnace charge preheating, then high-temperature molten iron is added into the converter, and the removal of phosphorus, sulfur and other impurity elements is rapidly completed by means of bottom-blown lime powder while heat is supplemented by adopting a dynamically adjusted top-blown oxygen and bottom-blown oxygen-lime powder-carbon powder blowing process.
The device can utilize low-cost carbon-neutral biomass charcoal as an efficient heat supplement agent, and top-blown oxygen fully plays a role in secondary combustion, so that the utilization efficiency of heat in the furnace is greatly improved; the bottom blowing oxygen-carbon powder-lime powder of the converter can obviously enhance the stirring of a molten pool and strengthen metallurgical reaction, avoid excessive foaming of slag, ensure that the blowing process is more stable and controllable, effectively inhibit the iron loss of the slag and the peroxidation of molten steel at the blowing end point, and obtain the molten steel with higher purity while reducing the consumption of raw and auxiliary materials for steelmaking.
The converter cooling material ratio of the smelting method of the device is improved to 30-50%, the consumption of lime per ton of steel is reduced by 5-20kg, and CO per ton of steel billet 2 The discharge amount is reduced by 50-100kg.
In conclusion, the device structure and the smelting method are simple, the close matching of the preheating stage, the melting-down stage and the air blowing stage can effectively reduce the FeO content at the end point of the slag, improve the metal yield, are very beneficial to the low-carbon smelting with high cooling-material ratio of the converter, and also reduce the lime consumption and CO 2 Discharging, and being beneficial to industrial large-scale production and popularization.
Drawings
In order to more clearly illustrate the technical solutions in the embodiments of the present invention, the drawings used in the description of the embodiments will be briefly introduced below, and it is obvious that the drawings in the description below are only some embodiments of the present invention, and it is obvious for those skilled in the art that other drawings may be obtained according to these drawings without creative efforts.
FIG. 1 is a schematic structural view of a converter low-carbon smelting device with a high cooling material ratio;
the reference numerals are illustrated below:
1-a converter main body, 2-a gas source, 3-a biomass carbon powder bin, 4-a lime powder bin, 5-a biomass carbon powder injection tank, 6-a lime powder injection tank, 7-1-a first injector, 7-2-a second injector, 8-a rotary joint, 9-a distributor, 10-a bottom blowing gun and 11-an oxygen lance.
Detailed Description
The technical solutions and the technical problems to be solved in the embodiments of the present invention will be described below with reference to the embodiments of the present invention. It is obvious that the described embodiments are only a part of the embodiments of the patent of the invention, and not all embodiments.
Example 1
The example is a bottom-spraying biomass charcoal high scrap ratio smelting method for a 300-ton converter.
The device used in the smelting method of the bottom spraying biomass charcoal high scrap ratio of the 300-ton converter comprises a converter main body 1, wherein an oxygen lance 11 penetrates through the top of the converter main body 1, a bottom blowing lance 10 is arranged at the bottom of the converter main body 1, a distributor 9 is communicated with the bottom of the bottom blowing lance 10, the distributor 9 is communicated with one end of a rotary joint 8 arranged on one side of the converter main body 1 through a connecting pipeline, and the other end of the rotary joint 8 is respectively communicated with a first injector 7-1 and a second injector 7-2;
the first ejector 7-1 is respectively communicated with an air source 2 and a biomass carbon powder injection tank 5, and the biomass carbon powder injection tank 5 is communicated with a biomass carbon powder bin 3;
the second ejector 7-2 is respectively communicated with the gas source 2 and the lime powder injection tank 6, and the lime powder injection tank 6 is communicated with the lime powder bin 4.
In the embodiment, 6 bottom blowing guns with a three-layer sleeve structure are arranged at the bottom of a 300-ton converter, and the spray guns are vertically penetrated and fixed at the bottom of the converter and are symmetrically distributed on the center line of a trunnion at the bottom of the converter.
The spray gun of this embodiment chooses for use 420J2 stainless steel, center tube diameter 23mm, and the width of inlayer outer layer circumferential weld is 1.5mm.
The device used in the smelting method of the embodiment relates to the pressure requirement of gas sources such as nitrogen, argon, oxygen, carbon dioxide, natural gas and the like with the pressure of 1.6-1.7MPa; the pressure of the central tube in the blowing stage is 1.0-1.3MPa, and the pressure of the protective gas of the inner-layer circular seam and the outer-layer circular seam is 0.8-1.0MPa.
The smelting method of the embodiment is based on a smelting device to perform top-blown oxygen and bottom-blown oxygen-biomass carbon powder-lime powder combined blowing, wherein the biomass carbon powder particle size of the biomass carbon powder injection tank 5 and the biomass carbon powder bin 3 is 50 meshes, and the lime powder particle size of the lime powder injection tank 6 and the lime powder bin 4 is 200 meshes. The specific smelting method comprises the following steps:
s1, preheating: adding scrap steel/DRI (hydrogen-based direct reduced iron) into a converter, and then blowing oxygen-biomass carbon powder from bottomAnd top-blowing oxygen, wherein: the flow rate of biomass carbon powder in a central tube of a single bottom blowing gun is 100kg/min; the central tube takes nitrogen, carbon dioxide or the mixture thereof as carrier gas, and the flow rate is 1000Nm 3 H; inner layer circumferential seam oxygen flow 200Nm 3 H; the outer layer circumferential seam takes nitrogen, argon or natural gas as protective gas, and the flow rate is 100Nm 3 H; performing high-efficiency cold charge preheating by using combustion reaction of biomass carbon powder and oxygen, wherein the preheating temperature is 600-800 ℃, and the time is 5-6min;
s2, melting: after the preheating stage of the step S1 is finished, immediately adding high-temperature and high-carbon molten iron into the converter, and continuously blowing oxygen from the bottom to the biomass carbon powder and oxygen from the top, wherein: the flow rate of biomass carbon powder in a central tube of a single bottom blowing gun is 200kg/min; the central tube takes the mixed gas of nitrogen and carbon dioxide as carrier gas, and the flow rate is 1800Nm 3 The proportion of nitrogen to carbon dioxide is respectively 50 percent; inner layer circumferential seam oxygen flow 300Nm 3 H; the outer layer circular seam takes natural gas as protective gas, and the flow rate is 300Nm 3 H; to accelerate the melting of scrap steel/DRI (hydrogen-based direct reduced iron), wherein the melting time is 7-8min;
s3, a melting stage: after the melting of the steel scrap/DRI (hydrogen-based direct reduced iron) in the melting stage in the step S2 is completed by a certain percentage, dynamically adjusting the bottom blowing gun from bottom blowing oxygen-biomass carbon powder to bottom blowing oxygen-lime powder, wherein: the lime powder flow of the central tube of the single bottom blowing gun is 200kg/min; the central tube takes oxygen as carrier gas with the flow rate of 1600Nm 3 H; the inner layer circular seam takes argon as protective gas, and the flow rate is 300Nm 3 H; the outer layer circular seam takes natural gas as protective gas, and the flow rate is 300Nm 3 H; rapidly removing impurity elements, and melting for 10-12min;
s4, an air blowing stage: and (5) stopping bottom blowing of the lime powder after the blowing in the melting stage of the step (S3) reaches the TSC (carbon fixation temperature), wherein: in order to prevent nitrogen increase in steel smelting, the central tube of the bottom blowing gun only blows argon with the flow rate of 1000Nm 3 H; the inner layer circular seam takes argon as protective gas, and the flow rate is 100Nm 3 H; the outer layer circumferential seam takes argon as protective gas, and the flow rate is 100Nm 3 H; during the stage, the pure gas supply mode is adjusted to the tapping, and the stirring of the molten pool is enhanced by large-flow bottom blowing so as to reduce the FeO content at the end point of the slag.
The results show that: adopt the bookAfter the smelting method of the embodiment is adopted, the converter blows to the end point, the blowing process is stable and controllable, and the iron loss of the slag and the molten steel peroxidation at the blowing end point are effectively inhibited; wherein: the cold material ratio reaches 35 percent, the consumption of per ton of steel lime is reduced by 15kg, and per ton of steel billet CO is reduced 2 The discharge amount is reduced by 80kg.
Example 2
The example is a smelting process with high scrap ratio of bottom-blown biomass charcoal for a 100 ton converter.
The device used in the smelting method of the bottom spraying biomass charcoal high scrap ratio of the 100-ton converter comprises a converter body 1, wherein an oxygen lance 11 penetrates through the top of the converter body 1, a bottom blowing gun 10 is arranged at the bottom of the converter body 1, a distributor 9 is communicated with the bottom of the bottom blowing gun 10, the distributor 9 is communicated with one end of a rotary joint 8 arranged on one side of the converter body 1 through a connecting pipeline, and the other end of the rotary joint 8 is respectively communicated with a first ejector 7-1 and a second ejector 7-2;
the first ejector 7-1 is respectively communicated with an air source 2 and a biomass carbon powder injection tank 5, and the biomass carbon powder injection tank 5 is communicated with a biomass carbon powder bin 3;
the second ejector 7-2 is respectively communicated with the gas source 2 and the lime powder injection tank 6, and the lime powder injection tank 6 is communicated with the lime powder bin 4.
In the embodiment, 2 bottom blowing guns with a three-layer sleeve structure are arranged at the bottom of the 100-ton converter, and the spray guns are vertically penetrated and fixed at the bottom of the converter and are symmetrically distributed on the center line of a trunnion at the bottom of the converter.
The spray gun material of this embodiment chooses for use 420J2 material, and the center tube diameter is 10mm, and the inlayer crack width is 1mm.
The device used by the smelting method of the embodiment relates to the gas source pressure requirements of nitrogen, argon, oxygen, carbon dioxide, natural gas and the like, and the pressure requirements are 1.6-1.7MPa; the pressure of the central tube in the converting stage is 1.0-1.3MPa, and the pressure of the protective gas of the inner and outer layer circular seams is 0.8-1.0MPa.
The smelting method of the embodiment relies on a smelting device to perform top-blown oxygen and bottom-blown oxygen-biomass carbon powder-lime powder combined blowing, wherein the biomass carbon powder injection tank 5 and the biomass carbon powder storage bin 3 relate to a biomass carbon powder particle size of 60 meshes, and the lime powder injection tank 6 and the lime powder storage bin 4 relate to a lime powder particle size of 180 meshes. The specific smelting method comprises the following steps:
s1, preheating: after scrap/DRI (hydrogen-based direct reduced iron) is added into the converter, bottom blowing oxygen-biomass carbon powder and top blowing oxygen are carried out, wherein: the flow rate of biomass carbon powder in a central tube of a single bottom blowing gun is 40kg/min; the central tube takes nitrogen, carbon dioxide or the mixture thereof as carrier gas, and the flow rate is 500Nm 3 H; inner layer circumferential seam oxygen flow 100Nm 3 H; the outer layer circumferential seam takes nitrogen, argon or natural gas as protective gas, and the flow rate is 100Nm 3 H; performing combustion reaction of biomass carbon powder and oxygen, and performing efficient cold charge preheating at 600-800 ℃ for 5-6min;
s2, melting: and (2) after the preheating stage of the step (S1) is finished, immediately adding high-temperature and high-carbon molten iron into the converter, and continuously blowing oxygen from bottom to biomass carbon powder and oxygen from top to bottom, wherein: the flow rate of biomass carbon powder in a central tube of a single bottom blowing gun is 80kg/min; the central tube takes nitrogen and carbon dioxide mixed gas as carrier gas, and the flow rate is 1000Nm 3 The ratio of nitrogen to carbon dioxide is 1; inner circumferential seam oxygen flow rate of 150Nm 3 H; the outer layer circumferential seams use natural gas as protective gas, and the flow rate is 150Nm 3 H; to accelerate the melting of scrap steel/DRI (hydrogen-based directly reduced iron), wherein the melting time is 7-8min;
s3, a melting stage: after 70% of the scrap steel/DRI (hydrogen-based direct reduced iron) in the melting stage in the step S2 is melted, dynamically adjusting the bottom blowing gun from bottom blowing oxygen-biomass carbon powder to bottom blowing oxygen-lime powder, wherein: the flow rate of lime powder of a central tube of a single bottom blowing gun is 80kg/min; the central tube takes oxygen as carrier gas, and the flow rate is 1000Nm 3 H; the inner layer circular seam takes argon as protective gas, and the flow is 100Nm 3 H; the outer layer circular seam takes natural gas as protective gas, and the flow rate is 100Nm 3 H; rapidly removing impurity elements, and melting for 10-12min;
s4, an air blowing stage: and (5) stopping bottom blowing of the lime powder after the blowing in the melting stage of the step (S3) reaches the TSC (carbon fixation temperature), wherein: in order to prevent nitrogen increase in steel smelting, the central tube of the bottom blowing gun only blows argon with the flow rate of 500Nm 3 H; the inner layer circular seam takes argon as protective gasFlow 100Nm 3 H; the outer layer circular seam takes argon as shielding gas, and the flow rate is 100Nm 3 H; in the stage, the steel tapping is regulated to be in a pure gas supply mode, and the stirring of a molten pool is enhanced by large-flow bottom blowing so as to reduce the FeO content at the end point of the slag.
The results show that: after the smelting method is adopted, the converter blows to the end point, the blowing process is stable and controllable, and the iron loss of the slag and the molten steel peroxidation at the blowing end point are effectively inhibited; wherein: the cold material ratio reaches 28 percent, the consumption of lime per ton of steel is reduced by 5kg, and CO per ton of steel blank 2 The discharge amount is reduced by 30kg.
Example 3
The example is a smelting method of bottom-spraying biomass charcoal high scrap ratio for a 200-ton converter.
The device used in the smelting method of the bottom spraying biomass charcoal high scrap ratio of the 200-ton converter comprises a converter body 1, wherein an oxygen lance 11 penetrates through the top of the converter body 1, a bottom blowing gun 10 is arranged at the bottom of the converter body 1, a distributor 9 is communicated with the bottom of the bottom blowing gun 10, the distributor 9 is communicated with one end of a rotary joint 8 arranged on one side of the converter body 1 through a connecting pipeline, and the other end of the rotary joint 8 is respectively communicated with a first ejector 7-1 and a second ejector 7-2;
the first ejector 7-1 is respectively communicated with an air source 2 and a biomass carbon powder injection tank 5, and the biomass carbon powder injection tank 5 is communicated with a biomass carbon powder bin 3;
the second injector 7-2 is respectively communicated with the gas source 2 and the lime powder injection tank 6, and the lime powder injection tank 6 is communicated with the lime powder bin 4.
In the embodiment, a plurality of bottom blowing guns with a three-layer sleeve structure are arranged at the bottom of the 200-ton converter, and the spray guns are vertically penetrated and fixed at the bottom of the converter and are symmetrically distributed on the center line of trunnions at the bottom of the converter.
The spray gun of this embodiment chooses for use what material, and the center tube diameter is 20mm, and the ectonexine crack width is 1.5mm.
The device used by the smelting method of the embodiment relates to the gas source pressure requirements of nitrogen, argon, oxygen, carbon dioxide, natural gas and the like, and the pressure requirements are 1.6-1.7MPa; the pressure of the central tube in the converting stage is 1.0-1.3MPa, and the pressure of the protective gas of the inner and outer layer circular seams is 0.8-1.0MPa.
The smelting method of the embodiment relies on a smelting device to perform top-blown oxygen and bottom-blown oxygen-biomass carbon powder-lime powder combined blowing, wherein the biomass carbon powder injection tank 5 and the biomass carbon powder storage bin 3 relate to a biomass carbon powder particle size of 60 meshes, and the lime powder injection tank 6 and the lime powder storage bin 4 relate to a lime powder particle size of 250 meshes. The specific smelting method comprises the following steps:
s1, preheating: after scrap/DRI (hydrogen-based direct reduced iron) is added into the converter, bottom blowing oxygen-biomass carbon powder and top blowing oxygen are carried out, wherein: the flow rate of biomass carbon powder in a central tube of a single bottom blowing gun is 80kg/min; the central tube takes nitrogen, carbon dioxide or the mixture thereof as carrier gas, and the flow rate is 800Nm 3 H; inner layer circumferential seam oxygen flow 200Nm 3 H; the outer layer circumferential seam takes nitrogen, argon or natural gas as protective gas, and the flow rate is 100Nm 3 H; performing high-efficiency cold charge preheating by using combustion reaction of biomass carbon powder and oxygen, wherein the preheating temperature is 600-800 ℃, and the time is 5-6min;
s2, melting: and (2) after the preheating stage of the step (S1) is finished, immediately adding high-temperature and high-carbon molten iron into the converter, and continuously blowing oxygen from bottom to biomass carbon powder and oxygen from top to bottom, wherein: the flow rate of biomass carbon powder in a central tube of a single bottom blowing gun is 150kg/min; the central tube takes the mixed gas of nitrogen and carbon dioxide as carrier gas, and the flow rate is 1500Nm 3 The proportion of nitrogen to carbon dioxide is 50 percent; inner layer circumferential seam oxygen flow 200Nm 3 H; the outer layer circular seam takes natural gas as protective gas, and the flow rate is 200Nm 3 H; to accelerate the melting of scrap steel/DRI (hydrogen-based direct reduced iron), wherein the melting time is 7-8min;
s3, a melting stage: after 90% of the scrap steel/DRI (hydrogen-based direct reduced iron) in the melting stage in the step S2 is melted, dynamically adjusting a bottom-blowing gun from bottom-blowing oxygen-biomass carbon powder to bottom-blowing oxygen-lime powder, wherein: the lime powder flow rate of a central tube of a single bottom blowing gun is 150kg/min; the central tube takes oxygen as carrier gas, and the flow rate is 1500Nm 3 H; the inner layer circular seam takes argon as protective gas, and the flow rate is 200Nm 3 H; the outer layer circular seam takes natural gas as protective gas, and the flow rate is 200Nm 3 H; to rapidly remove impurity elements for a melting time of10-12min；
S4, an air blowing stage: and (5) stopping bottom blowing of the lime powder after the blowing in the melting stage of the step (S3) reaches the TSC (carbon fixation temperature), wherein: in order to prevent nitrogen increase in steel smelting, the central tube of the bottom blowing gun only blows argon with the flow rate of 800Nm 3 H; the inner layer circular seam takes argon as protective gas, and the flow rate is 100Nm 3 H; the outer layer circular seam takes argon as shielding gas, and the flow rate is 100Nm 3 H; in the stage, the steel tapping is regulated to be in a pure gas supply mode, and the stirring of a molten pool is enhanced by large-flow bottom blowing so as to reduce the FeO content at the end point of the slag.
The results show that: after the smelting method is adopted, the converter blows to the end point, the blowing process is stable and controllable, and the iron loss of the slag and the molten steel peroxidation at the blowing end point are effectively inhibited; wherein: the cold material ratio reaches 35 percent, the consumption of lime per ton of steel is reduced by 10kg, and CO per ton of steel blank 2 The discharge amount is reduced by 60kg.
Example 4
The example is a smelting method for high scrap ratio of bottom-spraying biomass charcoal for a 150-ton converter.
The device used in the smelting method of the bottom spraying biomass charcoal high scrap ratio of the 150-ton converter comprises a converter body 1, wherein an oxygen lance 11 penetrates through the top of the converter body 1, a bottom blowing gun 10 is arranged at the bottom of the converter body 1, a distributor 9 is communicated with the bottom of the bottom blowing gun 10, the distributor 9 is communicated with one end of a rotary joint 8 arranged on one side of the converter body 1 through a connecting pipeline, and the other end of the rotary joint 8 is respectively communicated with a first ejector 7-1 and a second ejector 7-2;
the first ejector 7-1 is respectively communicated with an air source 2 and a biomass carbon powder injection tank 5, and the biomass carbon powder injection tank 5 is communicated with the biomass carbon powder bin 3;
the second ejector 7-2 is respectively communicated with the gas source 2 and the lime powder injection tank 6, and the lime powder injection tank 6 is communicated with the lime powder bin 4.
In the embodiment, 3 bottom blowing guns with a three-layer sleeve structure are arranged at the bottom of the 150-ton converter, and spray guns are vertically penetrated and fixed at the bottom of the converter and are symmetrically distributed on the center line of trunnions at the bottom of the converter.
The spray gun material of this embodiment chooses for use 420J2 material, and the center tube diameter is 14mm, and the ectonexine crack width is 1mm.
The device used by the smelting method of the embodiment relates to the gas source pressure requirements of nitrogen, argon, oxygen, carbon dioxide, natural gas and the like, and the pressure requirements are 1.6-1.7MPa; the pressure of the central tube in the converting stage is 1.0-1.3MPa, and the pressure of the protective gas of the inner and outer layer circular seams is 0.8-1.0MPa.
The smelting method of the embodiment is based on a smelting device to perform top-blown oxygen and bottom-blown oxygen-biomass carbon powder-lime powder combined blowing, wherein the biomass carbon powder particle size of the biomass carbon powder injection tank 5 and the biomass carbon powder bin 3 is 50 meshes, and the lime powder particle size of the lime powder injection tank 6 and the lime powder bin 4 is 200 meshes. The specific smelting method comprises the following steps:
s1, preheating: after scrap/DRI (hydrogen-based direct reduced iron) is added into the converter, bottom blowing oxygen-biomass carbon powder and top blowing oxygen are carried out, wherein: the flow rate of biomass carbon powder in a central tube of a single bottom blowing gun is 50kg/min; the central tube takes nitrogen, carbon dioxide or the mixture thereof as carrier gas, and the flow rate is 500Nm 3 H; inner layer circumferential seam oxygen flow 100Nm 3 H; the outer layer circumferential seam takes nitrogen, argon or natural gas as protective gas, and the flow rate is 50Nm 3 H; performing combustion reaction of biomass carbon powder and oxygen, and performing efficient cold charge preheating at 600-800 ℃ for 5-6min;
s2, melting: after the preheating stage of the step S1 is finished, immediately adding high-temperature and high-carbon molten iron into the converter, and continuously blowing oxygen from the bottom to the biomass carbon powder and oxygen from the top, wherein: the flow rate of biomass carbon powder in a central tube of a single bottom blowing gun is 100kg/min; the central tube takes the mixed gas of nitrogen and carbon dioxide as carrier gas, and the flow rate is 900Nm 3 H, the ratio of nitrogen to carbon dioxide is 1; inner circumferential seam oxygen flow rate of 150Nm 3 H; the outer layer circular seam takes natural gas as protective gas, and the flow rate is 150Nm 3 H; to accelerate the melting of scrap steel/DRI (hydrogen-based direct reduced iron), wherein the melting time is 7-8min;
s3, a melting stage: after 70% of scrap steel/DRI (hydrogen-based direct reduced iron) in the melting stage in the step S2 is melted, dynamically adjusting a bottom-blowing gun from bottom-blowing oxygen-biomass carbon powder to bottom-blowing oxygen-lime powder, wherein: single bottom blowing gunThe flow rate of the lime powder in the central tube is 100kg/min; the central tube takes oxygen as carrier gas, and the flow rate is 800Nm 3 H; the inner layer circular seam takes argon as protective gas, and the flow rate is 150Nm 3 H; the outer layer circumferential seams use natural gas as protective gas, and the flow rate is 150Nm 3 H; rapidly removing impurity elements, and melting for 10-12min;
s4, an air blowing stage: and (4) after blowing is carried out to TSC (carbon sequestration temperature) in the melting stage in the step (S3), stopping bottom blowing of the lime powder, wherein: in order to prevent nitrogen increase in steel smelting, the central tube of the bottom blowing gun only blows argon with the flow rate of 600Nm 3 H; the inner layer circular seam takes argon as protective gas, and the flow rate is 100Nm 3 H; the outer layer circular seam takes argon as shielding gas, and the flow rate is 100Nm 3 H; in the stage, the steel tapping is regulated to be in a pure gas supply mode, and the stirring of a molten pool is enhanced by large-flow bottom blowing so as to reduce the FeO content at the end point of the slag.
The results show that: after the smelting method is adopted, the converter blows to the end point, the blowing process is stable and controllable, and the iron loss of the slag and the molten steel peroxidation at the blowing end point are effectively inhibited; wherein: the cold material ratio reaches 38 percent, the consumption of lime per ton of steel is reduced by 20kg, and CO per ton of steel blank 2 The discharge amount is reduced by 40kg.
Example 5
The example is a bottom-spraying biomass charcoal high scrap ratio smelting method for a 250-ton converter.
The device used in the smelting method of the bottom spraying biomass charcoal high scrap ratio of the 250-ton converter comprises a converter body 1, wherein an oxygen lance 11 penetrates through the top of the converter body 1, a bottom blowing gun 10 is arranged at the bottom of the converter body 1, a distributor 9 is communicated with the bottom of the bottom blowing gun 10, the distributor 9 is communicated with one end of a rotary joint 8 arranged on one side of the converter body 1 through a connecting pipeline, and the other end of the rotary joint 8 is respectively communicated with a first ejector 7-1 and a second ejector 7-2;
the first ejector 7-1 is respectively communicated with an air source 2 and a biomass carbon powder injection tank 5, and the biomass carbon powder injection tank 5 is communicated with a biomass carbon powder bin 3;
the second ejector 7-2 is respectively communicated with the gas source 2 and the lime powder injection tank 6, and the lime powder injection tank 6 is communicated with the lime powder bin 4.
In the embodiment, 6 bottom blowing guns with a three-layer sleeve structure are arranged at the bottom of the 250-ton converter, and the spray guns are vertically penetrated and fixed at the bottom of the converter and are symmetrically distributed on the center line of a trunnion at the bottom of the converter.
The spray gun of this embodiment selects for use the carbon steel material, and the center tube diameter is 25mm, and the inlayer outer loop seam width is 2mm.
The device used in the smelting method of the embodiment relates to the pressure requirement of gas sources such as nitrogen, argon, oxygen, carbon dioxide, natural gas and the like with the pressure of 1.6-1.7MPa; the pressure of the central tube in the converting stage is 1.0-1.3MPa, and the pressure of the protective gas of the inner and outer layer circular seams is 0.8-1.0MPa.
The smelting method of the embodiment relies on a smelting device to perform top-blown oxygen and bottom-blown oxygen-biomass carbon powder-lime powder combined blowing, wherein the biomass carbon powder injection tank 5 and the biomass carbon powder storage bin 3 relate to a biomass carbon powder particle size of 80 meshes, and the lime powder injection tank 6 and the lime powder storage bin 4 relate to a lime powder particle size of 200 meshes. The specific smelting method comprises the following steps:
s1, preheating: after scrap/DRI (hydrogen-based direct reduced iron) is added into the converter, bottom blowing oxygen-biomass carbon powder and top blowing oxygen are carried out, wherein: the flow rate of biomass carbon powder in a central tube of a single bottom blowing gun is 120kg/min; the central tube takes nitrogen, carbon dioxide or the mixture thereof as carrier gas, and the flow rate is 1500Nm 3 H; inner layer circumferential seam oxygen flow 300Nm 3 H; the outer layer circumferential seam takes nitrogen, argon or natural gas as protective gas, and the flow rate is 150Nm 3 H; performing high-efficiency cold charge preheating by using combustion reaction of biomass carbon powder and oxygen, wherein the preheating temperature is 600-800 ℃, and the time is 5-6min;
s2, melting: and (2) after the preheating stage of the step (S1) is finished, immediately adding high-temperature and high-carbon molten iron into the converter, and continuously blowing oxygen from bottom to biomass carbon powder and oxygen from top to bottom, wherein: the flow rate of biomass carbon powder in a central tube of a single bottom blowing gun is 250kg/min; the central tube takes the mixed gas of nitrogen and carbon dioxide as carrier gas, and the flow rate is 2000Nm 3 The ratio of nitrogen to carbon dioxide is 50 percent; inner layer circumferential seam oxygen flow 300Nm 3 H; the outer layer circumferential seams use natural gas as protective gas, and the flow rate is 300Nm 3 H; to accelerate scrap/DRI (hydrogen radical direct reduction)Raw iron) for 7-8min;
s3, a melting stage: after 90% of the scrap steel/DRI (hydrogen-based direct reduced iron) in the melting stage in the step S2 is melted, dynamically adjusting the bottom blowing gun from bottom blowing oxygen-biomass carbon powder to bottom blowing oxygen-lime powder, wherein: the lime powder flow rate of a central tube of a single bottom blowing gun is 250kg/min; the central tube takes oxygen as carrier gas, and the flow rate is 2000Nm 3 H; the inner layer circular seam takes argon as protective gas, and the flow rate is 300Nm 3 H; the outer layer circumferential seams use natural gas as protective gas, and the flow rate is 300Nm 3 H; rapidly removing impurity elements, and melting for 10-12min;
s4, an air blowing stage: and (4) after blowing is carried out to TSC (carbon sequestration temperature) in the melting stage in the step (S3), stopping bottom blowing of the lime powder, wherein: in order to prevent nitrogen increase in steel smelting, the central tube of the bottom blowing gun only blows argon with the flow rate of 1200Nm 3 H; the inner layer circular seam takes argon as protective gas, and the flow rate is 150Nm 3 H; the outer layer circular seam takes argon as protective gas, and the flow rate is 150Nm 3 H; during the stage, the pure gas supply mode is adjusted to the tapping, and the stirring of the molten pool is enhanced by large-flow bottom blowing so as to reduce the FeO content at the end point of the slag.
The results show that: after the smelting method is adopted, the converter blows to the end point, the blowing process is stable and controllable, and the iron loss of the slag and the molten steel peroxidation at the blowing end point are effectively inhibited; wherein: the cold material ratio reaches 40 percent, the lime consumption per ton steel is reduced by 20kg, and CO per ton steel billet 2 The discharge amount is reduced by 90kg.
Example 6
The example is a smelting method of bottom-spraying biomass charcoal with high scrap ratio for an 80-ton converter.
The device used in the smelting method of the bottom spraying biomass charcoal high scrap ratio of the 80-ton converter comprises a converter body 1, wherein an oxygen lance 11 penetrates through the top of the converter body 1, a bottom blowing gun 10 is arranged at the bottom of the converter body 1, a distributor 9 is communicated with the bottom of the bottom blowing gun 10, the distributor 9 is communicated with one end of a rotary joint 8 arranged on one side of the converter body 1 through a connecting pipeline, and the other end of the rotary joint 8 is respectively communicated with a first ejector 7-1 and a second ejector 7-2;
the first ejector 7-1 is respectively communicated with an air source 2 and a biomass carbon powder injection tank 5, and the biomass carbon powder injection tank 5 is communicated with a biomass carbon powder bin 3;
the second ejector 7-2 is respectively communicated with the gas source 2 and the lime powder injection tank 6, and the lime powder injection tank 6 is communicated with the lime powder bin 4.
In the embodiment, 1 bottom blowing gun with a three-layer sleeve structure is arranged at the bottom of the 80-ton converter, and the spray guns are vertically penetrated and fixed at the bottom of the converter and are symmetrically distributed on the center line of trunnions at the bottom of the converter.
The spray gun material of this embodiment chooses for use 420J2 material, and the center tube diameter is 10mm, and the inlayer crack width is 1mm.
The device used in the smelting method of the embodiment relates to the pressure requirement of gas sources such as nitrogen, argon, oxygen, carbon dioxide, natural gas and the like with the pressure of 1.6-1.7MPa; the pressure of the central tube in the converting stage is 1.0-1.3MPa, and the pressure of the protective gas of the inner and outer layer circular seams is 0.8-1.0MPa.
The smelting method of the embodiment is based on a smelting device to perform top-blown oxygen and bottom-blown oxygen-biomass carbon powder-lime powder combined blowing, wherein the biomass carbon powder particle size of the biomass carbon powder injection tank 5 and the biomass carbon powder bin 3 is 40 meshes, and the lime powder particle size of the lime powder injection tank 6 and the lime powder bin 4 is 100 meshes. The specific smelting method comprises the following steps:
s1, preheating: after scrap/DRI (hydrogen-based direct reduced iron) is added into the converter, bottom blowing oxygen-biomass carbon powder and top blowing oxygen are carried out, wherein: the flow rate of biomass carbon powder in a central tube of a single bottom blowing gun is 40kg/min; the central tube takes nitrogen, carbon dioxide or the mixture thereof as carrier gas, and the flow rate is 600Nm 3 H; inner layer circumferential seam oxygen flow 100Nm 3 H; the outer layer circumferential seam takes nitrogen, argon or natural gas as protective gas, and the flow rate is 50Nm 3 H; performing combustion reaction of biomass carbon powder and oxygen, and performing efficient cold charge preheating at 600-800 ℃ for 5-6min;
s2, melting: and (2) after the preheating stage of the step (S1) is finished, immediately adding high-temperature and high-carbon molten iron into the converter, and continuously blowing oxygen from bottom to biomass carbon powder and oxygen from top to bottom, wherein: the flow of the biomass carbon powder in the central tube of the single bottom blowing gun is 80kg/min(ii) a The central tube takes the mixed gas of nitrogen and carbon dioxide as carrier gas, and the flow rate is 800Nm 3 The ratio of nitrogen to carbon dioxide is 1; inner layer circumferential seam oxygen flow 100Nm 3 H; the outer layer circumferential seams use natural gas as protective gas, and the flow rate is 100Nm 3 H; to accelerate the melting of scrap steel/DRI (hydrogen-based direct reduced iron), wherein the melting time is 7-8min;
s3, a melting stage: after the scrap steel/DRI (hydrogen-based direct reduced iron) in the melting stage in the step S2 is melted by 60%, dynamically adjusting a bottom blowing gun from bottom blowing oxygen-biomass carbon powder to bottom blowing oxygen-lime powder, wherein: the lime powder flow rate of the central tube of the single bottom blowing gun is 80kg/min; the central tube takes oxygen as carrier gas, and the flow rate is 800Nm 3 H; the inner layer circular seam takes argon as protective gas, and the flow rate is 100Nm 3 H; the outer layer circular seam takes natural gas as protective gas, and the flow rate is 100Nm 3 H; rapidly removing impurity elements, and melting for 10-12min;
s4, an air blowing stage: and (5) stopping bottom blowing of the lime powder after the blowing in the melting stage of the step (S3) reaches the TSC (carbon fixation temperature), wherein: in order to prevent nitrogen increase in steel smelting, the central tube of the bottom blowing gun only blows argon with the flow rate of 500Nm 3 H; the inner layer circular seam takes argon as protective gas, and the flow rate is 100Nm 3 H; the outer layer circular seam takes argon as shielding gas, and the flow rate is 100Nm 3 H; in the stage, the steel tapping is regulated to be in a pure gas supply mode, and the stirring of a molten pool is enhanced by large-flow bottom blowing so as to reduce the FeO content at the end point of the slag.
The results show that: after the smelting method is adopted, the converter blows to the end point, the blowing process is stable and controllable, and the iron loss of the slag and the molten steel peroxidation at the blowing end point are effectively inhibited; wherein: the cold material ratio reaches 30 percent, the lime consumption per ton steel is reduced by 8kg, and CO per ton steel billet 2 The discharge amount is reduced by 40kg.
In the scheme, the converter high-cold-material-ratio low-carbon smelting device provided by the invention has the advantages that the structural arrangement of the converter main body, the air source, the biomass carbon powder bin, the lime powder bin, the biomass carbon powder injection tank, the lime powder injection tank, the first injector, the second injector, the rotary joint, the distributor, the bottom blowing gun and the oxygen lance can effectively improve the heat supplementing effect, inclusion removal, reaction stability and the like of high scrap steel/DRI (hydrogen-based direct reduced iron) in comparison with the traditional converter smelting, and the converter high-cold-material-ratio low-carbon smelting device is beneficial to industrial large-scale production and popularization.
The invention provides a converter high-cold-material-ratio low-carbon smelting method of bottom-sprayed biomass carbon powder, which is characterized in that production is carried out according to a combined blown converter supporting top-blown oxygen and bottom-blown oxygen-carbon powder-lime powder, after scrap steel/DRI (hydrogen-based direct reduced iron) is added into the converter, the bottom-blown oxygen-carbon powder and the top-blown oxygen are firstly used for carrying out efficient furnace charge preheating, then high-temperature molten iron is added into the converter, and the dynamically adjusted top-blown oxygen and bottom-blown oxygen-lime powder-carbon powder blowing process is adopted, so that the removal of phosphorus, sulfur and other impurity elements is quickly completed by means of the bottom-blown lime powder while heat is supplemented.
The device can utilize low-cost carbon-neutral biomass charcoal as an efficient heat supplement agent, and top-blown oxygen fully plays a role in secondary combustion, so that the utilization efficiency of heat in the furnace is greatly improved; the bottom blowing oxygen-carbon powder-lime powder of the converter can obviously enhance the stirring of a molten pool and strengthen metallurgical reaction, avoid excessive foaming of slag, ensure that the blowing process is more stable and controllable, effectively inhibit the iron loss of the slag and the peroxidation of molten steel at the blowing end point, and obtain the molten steel with higher purity while reducing the consumption of raw and auxiliary materials for steelmaking.
The converter cold charge of the smelting method of the device of the invention is improved to 30-50%, the consumption of lime per ton steel is reduced by 5-20kg, and CO per ton steel billet 2 The discharge amount is reduced by 50-100kg.
In conclusion, the device structure and the smelting method are simple, the close matching of the preheating stage, the melting down stage and the air blowing stage can effectively reduce the FeO content at the end point of the furnace slag, improve the metal yield, are very beneficial to the low-carbon smelting with high cooling-material ratio of the converter, and reduce the lime consumption and CO 2 Discharging, and being beneficial to industrial large-scale production and popularization.
While the foregoing is directed to the preferred embodiment of the present invention, it will be appreciated by those skilled in the art that various changes and modifications may be made therein without departing from the principles of the invention as set forth in the appended claims.
Claims (10)
1. The converter high-cold-charge-ratio low-carbon smelting device is characterized by comprising a converter main body, wherein an oxygen lance penetrates through the top of the converter main body, a bottom blowing lance is arranged at the bottom of the converter main body, a distributor is communicated with the bottom blowing lance and is communicated with one end of a rotary joint arranged on one side of the converter main body through a connecting pipeline, and the other end of the rotary joint is respectively communicated with a first ejector and a second ejector;
the first ejector is respectively communicated with an air source and a biomass carbon powder injection tank, and the biomass carbon powder injection tank is communicated with the biomass carbon powder bin;
the second ejector is respectively communicated with a gas source and a lime powder injection tank, and the lime powder injection tank is communicated with the lime powder bin.
2. The converter high-cold-material-ratio low-carbon smelting device of claim 1, wherein the bottom blowing gun is of a triple sleeve structure, a main pipeline is a biomass carbon powder and lime powder channel, and an inner layer circular seam and an outer layer circular seam are protective gas channels.
3. The converter high-cold-material-ratio low-carbon smelting device according to claim 1, wherein the particle size of the biomass carbon powder in the biomass carbon powder bin is 30-80 meshes, and the particle size of the lime powder in the lime powder bin is 150-250 meshes.
4. The high-cold-ratio low-carbon smelting device of the converter according to claim 1, wherein the number of the bottom blowing guns is 2-8 according to the nominal capacity of the converter.
5. The smelting method of the converter low-carbon smelting device with the high cooling material ratio is characterized by comprising the following steps:
s1, preheating: after scrap steel/DRI (hydrogen-based directly reduced iron) is added into a converter, bottom blowing oxygen-biomass carbon powder and top blowing oxygen are carried out, and efficient cold charge preheating is carried out by utilizing combustion reaction of the biomass carbon powder and the oxygen;
s2, melting: after the preheating stage of the step S1 is finished, immediately adding high-temperature and high-carbon molten iron into the converter, and continuously blowing oxygen from bottom to biomass carbon powder and oxygen from top to accelerate the melting of scrap steel/DRI (hydrogen-based direct reduced iron);
s3, a melting stage: after 70-80% of the scrap steel/DRI (hydrogen-based direct reduced iron) in the melting stage in the step S2 is melted, dynamically adjusting a bottom blowing gun from bottom blowing oxygen-biomass carbon powder to bottom blowing oxygen-lime powder so as to quickly remove impurity elements;
s4, an air blowing stage: and (5) after the melting stage in the step (S3) is blown to TSC (carbon fixation temperature), stopping bottom blowing of the lime powder, and adjusting the gas supply mode to the pure gas supply mode during the stage until tapping.
6. The smelting method of the converter high cold burden ratio low carbon smelting device according to claim 5, wherein in the step S1, oxygen is blown into the biomass carbon powder and the biomass carbon powder flows through a central pipe of a single bottom blowing gun at a rate of 50-100kg/min; the central tube takes nitrogen, carbon dioxide or the mixture thereof as carrier gas, and the flow rate is 1000-2000Nm 3 H; inner layer circumferential seam oxygen flow rate is 100-300Nm 3 H; the outer layer circumferential seam takes nitrogen, argon or natural gas as protective gas, and the flow rate is 100-300Nm 3 /h。
7. The smelting method of the converter high-cold-burden-ratio low-carbon smelting device according to claim 5, wherein in the step S2, oxygen is continuously blown from the bottom to the biomass carbon powder and oxygen is continuously blown from the top, and the flow rate of the biomass carbon powder in the central pipe of the single bottom blowing gun is 100-200kg/min; the central tube takes nitrogen, carbon dioxide or the mixture thereof as carrier gas, and the flow rate is 1000-2000Nm 3 H; the oxygen flow rate of the inner circumferential seam is 100-300Nm 3 H; the outer layer circumferential seam takes nitrogen, argon or natural gas as protective gas, and the flow is 100-300Nm 3 /h。
8. The smelting method of the high-cold-material-ratio low-carbon smelting device of the converter according to claim 5, wherein in the step S3, oxygen-lime powder is blown from the bottom, and lime powder flows are blown from the central pipe of a single bottom blowing gunThe dosage is 100-200kg/min; the central tube takes oxygen, carbon dioxide, argon or the mixture thereof as carrier gas, and the flow rate is 1000-2000Nm 3 H; the inner layer circumferential seam takes nitrogen, argon or natural gas as protective gas, and the flow rate is 100-300Nm 3 H; the outer layer circumferential seam takes nitrogen, argon or natural gas as protective gas, and the flow rate is 100-300Nm 3 /h。
9. The smelting method for the high-cold-material-ratio low-carbon smelting device of the converter according to claim 5, wherein in the pure gas supply mode in the step S4, only argon is blown into a single bottom blowing gun central pipe at the flow rate of 800-1600Nm 3 H; the inner layer circumferential seam takes argon or natural gas as protective gas, and the flow rate is 100-200Nm 3 H; the outer layer circumferential seam takes argon or natural gas as protective gas, and the flow is 100-200Nm 3 /h。
10. The smelting method of the converter high cold burden ratio low carbon smelting device according to any one of claims 6 to 9, characterized in that the pressure requirements of gas sources such as nitrogen, argon, oxygen, carbon dioxide and natural gas related to the central tube carrier gas and the inner and outer layer circumferential seam protective gas are not lower than 1.6MPa; the pressure of the central tube in the converting stage is 1.0-1.3MPa, and the pressure of the protective gas of the inner and outer layer circular seams is 0.8-1.0MPa.
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