A blast furnace injection material

Abstract

The application discloses a blast furnace injection material and relates to the technical field of metallurgical production. The blast furnace injection material comprises combustion improver, anthracite, bituminous coal and abandoned agricultural and forestry biomass particles; the combustion improver comprises steel slag powder, quicklime powder and siderite; the combustion improver, the anthracite and the bituminous coal are mixed and put into a coal mill to be ground into coal powder; the coal powder is mixed with dry quenching dust to prepare mixed coal powder; and the mixed coal powder and the abandoned agricultural and forestry biomass particles are injected into a tuyere raceway of a blast furnace according to a ratio of 7:1 to 4:1. The combustion improver for improving the combustion effect of the coal for blast furnace injection is prepared by using the secondary products of the steel smelting process, i.e. the steel slag powder and the siderite, the source of which is very extensive, and the price of which is low, so that the fuel cost can be effectively reduced; when the dry quenching dust is added to replace the anthracite, the combustion effect of the coal powder in the furnace can be improved, the utilization rate of the coal powder in the furnace can be improved, and the quicklime powder in the combustion improver can absorb part of the harmful gases such as sulfur dioxide generated by combustion.

Description

Technical Field

[0001] This invention belongs to the field of metallurgical production technology, and in particular relates to a blast furnace injection material. Background Technology

[0002] In recent years, with the increasingly tight supply of coke and the continuous rise in the cost of ironmaking fuel, steel enterprises have faced increasing pressure to reduce costs. The consumption of pulverized coal is a significant factor affecting its cost. Pulverized coal injection technology for blast furnaces is one of the most effective methods for saving coke and reducing pig iron costs in blast furnace ironmaking. Therefore, developing auxiliary pulverized coal injection fuels for blast furnaces is of great practical significance for the sustainable development of steel enterprises.

[0003] Coking plants generate a large amount of dry quenching ash annually, occupying significant storage space. In terms of its main composition, dry quenching ash consists of fine coal powder, coke powder, and a small amount of dust. From an industrial analysis perspective, the composition of dry quenching ash is extremely similar to that of anthracite used in blast furnace injection, characterized by low volatile matter, high fixed carbon content, and low sulfur content. Based on this, some domestic ironmaking experts have proposed optimizing the blast furnace injection structure: using dry quenching ash as an auxiliary injection material to replace a certain proportion of anthracite, and mixing it with bituminous coal for blast furnace injection.

[0004] As a secondary resource of coking plants, dry quenching dust is cheaper than anthracite. Some dry quenching dust has been successfully used as an auxiliary injection in blast furnaces, greatly expanding the range of blast furnace fuel injection and bringing huge economic benefits to coking and steel enterprises.

[0005] For example, Chinese invention patent document CN104357073A discloses a method for using dry quenching coke dust in coal blending. Specifically, it discloses that the dust generated daily from dry quenching is transported to the coal storage yard through an ash discharge port and stored separately near low-sulfur coking coal (sulfur content <0.4%) and low-ash lean coal (ash content <8.5%). Using the blending ratio required by the loader blending instructions in the coal preparation workshop, the dry quenching dust is mixed with the low-ash coking coal and low-sulfur lean coal at a ratio of 1:5. The dust is mixed in a 5:1 weight ratio to form a new mixed dust. The mixed dust is then transported to the coal blending silo and mixed with 1 / 3 coking coal, gas coal, and a 7:3 weight ratio of coking coal + lean coal and fat coal to form the furnace feed coal. The mixed dust, 1 / 3 coking coal, gas coal, and the 7:3 weight ratio of coking coal + lean coal and fat coal account for 15%, 32%, 15%, 21%, and 17% of the furnace feed coal, respectively. The furnace feed coal is crushed, water is added, and it is then transported to the coal storage silo for coking production, replacing some of the lean coal for coking.

[0006] However, the current problem is that dry quenching dust is only used for coal blending, and there is a lack of a complete process to use dry quenching dust as an auxiliary injection material for blast furnace. The proportion of dry quenching dust used is also very small. The combustion rate of pulverized coal in the swirl zone is generally less than 70%. The ash content of dry quenching dust is higher than that of anthracite, and the calorific value is lower. Directly replacing anthracite in a large proportion will result in a large amount of incompletely burned pulverized coal entering the blast furnace, affecting the fluidity of blast furnace slag and the quality of molten iron. To address this issue, a blast furnace injection material is proposed, providing a technical solution to the aforementioned problems. Summary of the Invention

[0007] The purpose of this invention is to provide a blast furnace injection material to solve the problems mentioned in the background art.

[0008] To solve the above-mentioned technical problems, the present invention is achieved through the following technical solution: This invention relates to a blast furnace injection material, comprising a combustion aid, anthracite, bituminous coal, and waste agricultural and forestry biomass pellets; The combustion aid includes steel slag powder, quicklime powder, and siderite. The combustion aid, anthracite, and bituminous coal are mixed and then ground into pulverized coal using a coal mill. The pulverized coal is mixed with dry quenching dust to obtain mixed pulverized coal, and the mixed pulverized coal and waste agricultural and forestry biomass particles are injected into the tuyeres of the blast furnace in a ratio of 7:1 to 4:1.

[0009] Furthermore, the mass percentage of each component in the combustion aid is as follows: 30%–40% steel slag powder, 30%–40% quicklime powder, and 20%–30% siderite.

[0010] Furthermore, the mass ratio of anthracite to bituminous coal is 1.2:1 to 1:1, the amount of combustion aid added is 1% to 1.5% of the total mass of anthracite and bituminous coal, and the proportion of coal powder ground to -0.074mm exceeds 80%.

[0011] Furthermore, the mixing ratio of the pulverized coal to the dry quenching dust is 8:1 to 4:1.

[0012] Furthermore, the waste agricultural and forestry biomass pellets are one or more of wood chips, sawdust, rice husks and straw pellets, and are dried to a moisture content of less than 10% and a diameter of 5-8 mm before use.

[0013] Furthermore, the steel slag powder is one or more of converter slag powder, electric furnace slag powder, and refining furnace slag powder.

[0014] The present invention has the following beneficial effects: This invention uses steel slag powder and siderite, secondary products of the steelmaking process, to produce a combustion aid that improves the combustion effect of pulverized coal for blast furnace injection. These materials are widely available, inexpensive, and can effectively reduce fuel costs. When dry quenching ash is added to replace anthracite, it can improve the combustion effect of pulverized coal in the furnace and improve its utilization rate. The quicklime powder in the combustion aid can absorb some of the harmful gases such as sulfur dioxide generated during combustion.

[0015] This invention increases the residence time of pulverized coal by introducing waste agricultural and forestry biomass pellets. Firstly, the diameter of the biomass pellets is significantly larger than that of pulverized coal, resulting in a lower velocity and longer residence time. The combustion products are primarily gaseous reducing agents, producing fewer unburned particles compared to pulverized coal. Secondly, the low density and low inertia of these biomass pellets allow them to more easily circulate within the swirl zone, driving and strengthening the swirl of pulverized coal particles and extending the residence time. While burning rapidly themselves, these biomass pellets also provide a large amount of volatile matter for combustion, promoting the combustion of pulverized coal and thus increasing the pulverized coal combustion rate. This method improves the permeability of the blast furnace, promotes smooth operation, and allows the average coal ratio in blast furnace smelting to remain at 192-195 kg / t. Implementation

[0016] The technical solutions in the embodiments of the present invention will be clearly and completely described below. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention. Example

[0017] This invention relates to a blast furnace injection material, comprising a combustion aid, anthracite, bituminous coal, and waste agricultural and forestry biomass pellets; This example illustrates the blast furnace injection process at a steel company in Tangshan, as detailed below: (1) The pulverized coal combustion aid for blast furnace injection includes, by mass percentage: 35% steel slag powder, 40% quicklime powder, and 25% siderite; (2) Mix Yangquan anthracite, Lu'an anthracite, imported anthracite, Shenhua bituminous coal and combustion aid in a mass ratio of 20:26:10.5:42:1.5 and grind them into coal powder with a diameter of less than 0.08 mm in a coal mill. (3) Mix coal powder and dry quenching dust at a mass ratio of 6:1 to obtain mixed coal powder. Inject the mixed coal powder and wood chips into the tuyeres of the blast furnace. The total flow rate of the tuyeres is 0.6 kg / s, the flow rate of the carrier gas is 0.013 kg / s, and the mass ratio of the mixed coal powder to the wood chips is 6:1.

[0018] In this embodiment, the average fuel price is 1720 yuan / ton (combining bituminous coal, anthracite, dry quenching dust, wood chips, etc.), and the average coal ratio in blast furnace smelting is 193 kg / t.

[0019] If used according to existing technology, the specifics are as follows: Yangquan anthracite, Lu'an anthracite, imported anthracite, and Shenhua bituminous coal are ground into pulverized coal in a coal mill at a mass ratio of 20:27:13:40 and then sent to the blast furnace for injection. The price of the injected coal is 1780 yuan per ton, and the average coal ratio in blast furnace smelting is 195 kg / t. Example

[0020] This invention relates to a blast furnace injection material, comprising a combustion aid, anthracite, bituminous coal, and waste agricultural and forestry biomass pellets; This example illustrates the blast furnace injection process of a steel company in Jiangsu Province, as detailed below: (1) The pulverized coal combustion aid for blast furnace is prepared by mass percentage as follows: 38% steel slag powder, 40% quicklime powder, and 22% siderite. (2) Mix Hengyuan anthracite, Lanhua Kechuang anthracite, imported anthracite, Shenhua bituminous coal and combustion aid in a mass ratio of 16:21:20:42:1 and grind them into coal powder with a diameter of less than 0.08 mm in a coal mill. (3) Mix coal powder and dry quenching dust at a mass ratio of 5:1 to obtain mixed coal powder. Inject the mixed coal powder and straw particles into the tuyeres of the blast furnace. The total flow rate of the tuyeres is 0.6 kg / s, the carrier gas flow rate is 0.014 kg / s, and the mass ratio of mixed coal powder to straw particles is 5:1.

[0021] In this embodiment, the average fuel price is 1663 yuan / ton (combining bituminous coal, anthracite, dry quenching dust, straw, etc.), and the average coal ratio for blast furnace smelting is 192 kg / t.

[0022] If used according to existing technology, then: Hengyuan anthracite, Lanhua Kechuang anthracite, imported anthracite, and Shenhua bituminous coal were ground into pulverized coal in a coal mill at a mass ratio of 17:22:20:41 and then fed into the blast furnace for injection. The price of the injected coal was 1,753 yuan per ton, and the average coal ratio in the blast furnace smelting was 195 kg / t. Example

[0023] This invention relates to a blast furnace injection material, comprising a combustion aid, anthracite, bituminous coal, and waste agricultural and forestry biomass pellets; This example illustrates the blast furnace injection process of a steel company in Jiangxi Province, as detailed below: (1) The pulverized coal combustion aid for blast furnace is prepared by mass percentage as follows: 40% steel slag powder, 38% quicklime powder, and 22% siderite. (2) Mix Hengyuan anthracite, Lanhua Kechuang anthracite, Henan Nenghua anthracite, Jiangxi Yiyuan bituminous coal and combustion aid in a mass ratio of 21:13:21.7:43:1.3 and grind them into coal powder with a diameter of less than 0.08 mm in a coal mill. (3) Mix coal powder and dry quenching dust at a mass ratio of 6:1 to obtain mixed coal powder. Inject the mixed coal powder and wood chips into the tuyeres of the blast furnace. The total flow rate of the tuyeres is 0.6 kg / s, the flow rate of the carrier gas is 0.015 kg / s, and the mass ratio of the mixed coal powder to the wood chips is 6:1.

[0024] In this embodiment, the average fuel price is 1686 yuan / ton (combining bituminous coal, anthracite, dry quenching coke dust, wood chips, etc.), and the average coal ratio in blast furnace smelting is 193 kg / t.

[0025] If used according to existing technology, then: Hengyuan anthracite, Lanhua Kechuang anthracite, imported anthracite, and Shenhua bituminous coal were ground into pulverized coal in a coal mill at a mass ratio of 17:22:20:41 and then fed into the blast furnace for injection. The price of the injected coal was 1,753 yuan per ton, and the average coal ratio in the blast furnace smelting was 194 kg / t. Example

[0026] This invention relates to a blast furnace injection material, comprising a combustion aid, anthracite, bituminous coal, and waste agricultural and forestry biomass pellets; This example illustrates the blast furnace injection process of a steel company in Hubei Province, as detailed below: (1) The pulverized coal combustion aid for blast furnace is prepared by mass percentage as follows: 38% steel slag powder, 40% quicklime powder, and 22% siderite. (2) Mix Yangquan anthracite, imported anthracite, Henan Energy Chemical anthracite, Shenhua bituminous coal and combustion aid in a mass ratio of 19:16:21.5:42:1.5 and grind them into coal powder with a diameter of less than 0.08 mm in a coal mill. (3) Mix pulverized coal and dry quenching dust at a mass ratio of 5:1. Inject the mixed pulverized coal and wood pellets into the tuyeres of the blast furnace. The total flow rate of the tuyeres is 0.6 kg / s, the flow rate of the carrier gas is 0.013 kg / s, and the mass ratio of the mixed pulverized coal and wood pellets is 6:1.

[0027] In this embodiment, the average fuel price is 1681 yuan / ton (combining bituminous coal, anthracite, dry quenching coke dust, wood chips, etc.), and the average coal ratio in blast furnace smelting is 193 kg / t.

[0028] If used according to existing technology, the specifics are as follows: Hengyuan anthracite, Lanhua Kechuang anthracite, imported anthracite, and Shenhua bituminous coal were ground into pulverized coal in a coal mill at a mass ratio of 20:17:21:42 and then fed into the blast furnace for injection. The price of the injected coal was 1,773 yuan per ton, and the average coal ratio in the blast furnace smelting was 194 kg / t. Example

[0029] This invention relates to a blast furnace injection material, which includes a combustion aid, anthracite, bituminous coal, and waste agricultural and forestry biomass pellets; Among them, waste agricultural and forestry biomass pellets can be one or more of wood chips, sawdust, rice husks and straw pellets, and must be dried to a moisture content of less than 10% and a diameter of 5-8 mm before use; By weight percentage, the combustion improver comprises the following components: The steel slag powder is 30%–40%, the quicklime powder is 30%–40%, and the siderite is 20%–30%. Among them, steel slag powder can be one or more of converter slag powder, electric furnace slag powder and refining furnace slag powder, and no specific limitation is made here.

[0030] The combustion aid, anthracite, and bituminous coal are mixed and then ground into pulverized coal in a coal mill. Furthermore, the mass ratio of anthracite to bituminous coal is between 1.2:1 and 1:1, the amount of combustion aid added can be 1% to 1.5% of the total mass of anthracite and bituminous coal, and the proportion of coal powder ground to -0.074mm exceeds 80%. Mixed coal powder is prepared by mixing coal powder with dry quenching dust. When using it, the mixed coal powder and waste agricultural and forestry biomass pellets are injected into the tuyeres of the blast furnace. The ratio of coal powder to waste agricultural and forestry biomass pellets can be between 7:1 and 4:1. The total flow rate injected into the tuyeres can be 0.5~0.8 kg / s, and the carrier gas flow rate can be 0.013~0.016 kg / s. The mixing ratio of pulverized coal and dry quenching dust can be 8:1 to 4:1.

[0031] In summary, this invention uses dry quenching coke dust as an auxiliary injection material in the blast furnace, replacing a certain proportion of anthracite, and mixes it with bituminous coal for blast furnace injection. By injecting waste agricultural and forestry biomass pellets into the blast furnace tuyeres, the combustion effect of pulverized coal in the furnace is improved. At the same time, the entire process ensures that the pulverized coal has a high combustion rate and does not affect the fluidity of the subsequent blast furnace slag.

[0032] Because the price of dry quenching coke dust is 400-600 yuan / ton lower than that of anthracite, and assuming that 60% of the coal used in blast furnace injection is anthracite, dry quenching coke dust can replace 20% of the anthracite, thus reducing fuel costs by 48-72 yuan per ton of coal, significantly lowering operating costs.

[0033] In the description of this specification, references to terms such as "an embodiment," "example," "specific example," etc., indicate that a specific feature, structure, material, or characteristic described in connection with that embodiment or example is included in at least one embodiment or example of the invention. In this specification, illustrative expressions of the above terms do not necessarily refer to the same embodiment or example. Furthermore, the specific features, structures, materials, or characteristics described may be combined in any suitable manner in one or more embodiments or examples.

[0034] The preferred embodiments of the present invention disclosed above are merely illustrative of the invention. These preferred embodiments do not exhaustively describe all details, nor do they limit the invention to the specific implementations described. Clearly, many modifications and variations can be made based on the content of this specification. This specification selects and specifically describes these embodiments to better explain the principles and practical applications of the invention, thereby enabling those skilled in the art to better understand and utilize the invention. The invention is limited only by the claims and their full scope and equivalents.

Claims

1. A blast furnace injection material, characterized in that, This includes combustion aids, anthracite, bituminous coal, and waste agricultural and forestry biomass pellets; The combustion aid includes steel slag powder, quicklime powder, and siderite. The combustion aid, anthracite, and bituminous coal are mixed and then ground into pulverized coal using a coal mill. The pulverized coal is mixed with dry quenching dust to obtain mixed pulverized coal. The mixed pulverized coal and waste agricultural and forestry biomass particles are injected into the tuyeres of the blast furnace at a mass ratio of 7:1 to 4:

1. The mass percentages of each component in the combustion aid are as follows: 30%–40% steel slag powder, 30%–40% quicklime powder, and 20%–30% siderite.

2. The blast furnace injection material according to claim 1, characterized in that, The mass ratio of anthracite to bituminous coal is 1.2:1 to 1:1, the amount of combustion aid added is 1% to 1.5% of the total mass of anthracite and bituminous coal, and the proportion of coal powder ground to -0.074mm exceeds 80%.

3. The blast furnace injection material according to claim 1, characterized in that, The mass ratio of the pulverized coal to the dry quenching dust is 8:1 to 4:

1.

4. The blast furnace injection material according to claim 1, characterized in that, The waste agricultural and forestry biomass pellets are one or more of wood chips, sawdust, rice husks and straw pellets, and are dried to a moisture content of less than 10% and a diameter of 5-8 mm before use.

5. The blast furnace injection material according to claim 1, characterized in that, The steel slag powder is one or more of converter slag powder, electric furnace slag powder, and refined furnace slag powder.