Method for determining the composition of multi-media injection blast furnace bosh gas

Abstract

The present invention relates to a method for determining the composition of multi-media injection blast furnace bosh gas, and belongs to the field of blast furnace ironmaking. The specific method is as follows: first, determine the type of blast furnace tuyere injection medium, input the composition, injection amount and coke composition of each injection medium of the tuyere; secondly, calculate the amount of coke consumed in the tuyere whirlpool zone; then, respectively calculate the content of CO, N2, H2 and SiO converted from each injection medium and coke; then, calculate the content of each component of the bosh gas; finally, calculate the total bosh gas volume and the proportion of each component from the content of each component of the bosh gas. The present invention overcomes the problem of deviation in the traditional bosh gas volume calculation method, can accurately calculate the blast furnace bosh gas volume and composition, provide reliable data for the calculation of important blast furnace parameters-bosh gas volume index and theoretical combustion temperature, and provide better guidance for blast furnace operation.

Description

Technical Field

[0001] The invention belongs to the field of blast furnace ironmaking and relates to a method for determining the composition of multi-media injection blast furnace bosh gas. Background Art

[0002] The blast furnace is one of the main equipment for producing molten iron at home and abroad. The bosh gas volume index and the theoretical combustion temperature are two important parameters for blast furnace smelting. Among them, the bosh gas volume index is the empty tower flow rate of the gas produced in the tuyere vortex zone under standard conditions, which is an important indicator for evaluating the production efficiency of the blast furnace. The theoretical combustion temperature is an important reference indicator for judging the thermal state of the blast furnace hearth. The accuracy of the calculation of the bosh gas volume directly determines the accuracy of the above two parameters. Inaccurate calculation of the theoretical combustion temperature and the bosh gas volume index may cause the blast furnace operator to misjudge the furnace condition and affect the stable operation of the blast furnace. Under the condition of pulverized coal injection in the blast furnace, the bosh gas volume V BG Generally adopted Calculated, where V B is the air volume, excluding oxygen enrichment, m 3 / min; V O2 is the total oxygen enrichment, m 3 / min; W B is the blast humidity, g / m 3 ;P c is the amount of pulverized coal injected, kg / h; H is the hydrogen content of pulverized coal, %. This formula only considers the effects of fixed carbon in pulverized coal and hydrogen in volatiles, but does not consider the effects of CO2 in volatiles, C, CO, N2, H2O in hydrocarbons, physical water in pulverized coal, CO produced by reduction of SiO2 and Fe2O3 in pulverized coal ash, and coal injection carrier gas. Carbon emissions from blast furnace processes account for more than 70% of carbon emissions from the high-to-long process.

[0003] The composition of the bosh gas, especially the content of CO and H2 in the bosh gas, directly affects the reduction behavior of the blast furnace charge. After the blast furnace adopts the new carbon reduction technology, the tuyere changes from the original two injection media of hot air and coal injection to three injection media of hot air, coal powder, and CO-H2-CH4-CH4 rich reducing gas. The calculation formula of the amount and composition of the bosh gas in the traditional coal injection blast furnace is no longer applicable to the low-carbon blast furnace multi-media injection blast furnace. Summary of the invention

[0004] In view of this, the object of the present invention is to provide a method for determining the composition of multi-media injection blast furnace bosh gas, so as to overcome the problem of deviation in the traditional method for calculating the amount of bosh gas.

[0005] In order to achieve the above object, the present invention provides the following technical solutions:

[0006] A method for determining the composition of multi-media injection blast furnace bosh gas comprises the following steps:

[0007] S1 determines the type of the blast furnace tuyere injection medium, inputs the composition, injection amount and coke composition of each injection medium of the tuyere;

[0008] S2 is calculated by the mass conservation of oxygen before and after the reaction in the tuyere raceway, and the amount of coke consumed in the tuyere raceway is calculated;

[0009] S3 According to the characteristics of the tuyere injection medium and the tuyere coke consumption, the coal gas after the reaction in the tuyere cyclotron zone is composed of four components: CO, N2, H2 and SiO. According to the Gass law, the contents of CO, N2, H2 and SiO converted from each injection medium and coke are calculated according to the composition and consumption of the tuyere injection medium and coke.

[0010] S4 calculates the content of each component of the bosh gas according to the content of CO, N2, H2 and SiO produced by each injection medium and coke;

[0011] S5 calculates the total amount of bosh gas and the proportion of each component based on the content of each component of the bosh gas.

[0012] Optionally, the blast furnace tuyere blowing medium is one or more combinations of air, coal powder, CO-H2-CH4-rich reducing gas, and oxygen; the tuyere blowing medium is CO-H2-CH4-rich reducing gas, which is one or more of coke oven gas, natural gas, coalbed methane, converter gas decarbonization gas, Ouye furnace decarbonization gas, blast furnace top decarbonization gas, etc.

[0013] Optionally, the components of the coal powder that can be converted into the bosh gas mainly include coal powder fixed carbon, coal powder volatile matter, SiO2 and Fe2O3 in coal powder ash, and coal powder physical water; the components of the coke that can be converted into the bosh gas mainly include coke fixed carbon, SiO2 and Fe2O3 in coke ash.

[0014] Optionally, the fixed carbon in the pulverized coal combines with oxygen to generate CO, and the ratio of CO entering the bosh gas is 60% to 100%, and all volatiles are converted into CO, H2 and N2 and enter the bosh gas.

[0015] Optionally, the ratio of SiO2 in the coal powder and coke ash reduced to CO and SiO is between 0% and 50%.

[0016] Optionally, the ratio of Fe2O3 in the coal powder and coke ash reduced to CO is between 50% and 100%.

[0017] Optionally, all of the oxygen in the air and the oxygen in the injection medium combine with carbon in the coke, coal powder, and hydrocarbons in the injection gas to form CO and enter the furnace gas.

[0018] Optionally, the composition input of the coal powder in the tuyere injection medium includes industrial analysis components, coal powder ash components and coal powder volatile components.

[0019] Optionally, the air in the blast furnace tuyere injection medium can be converted into the components of the bosh gas mainly including nitrogen and water.

[0020] Optionally, the air composition input in the tuyere spraying medium includes oxygen content, nitrogen content and humidity content.

[0021] The beneficial effects of the present invention are:

[0022] The method for determining the composition of the multi-media injection blast furnace bosh gas described in the present invention overcomes the problem of deviation in the traditional bosh gas quantity calculation method, can accurately calculate the blast furnace bosh gas quantity and composition, and provide reliable data for the calculation of important blast furnace parameters - bosh gas quantity index and theoretical combustion temperature, thereby providing better guidance for blast furnace operation.

[0023] Other advantages, objectives and features of the present invention will be described in the following description to some extent, and to some extent, will be obvious to those skilled in the art based on the following examination and study, or can be taught from the practice of the present invention. The objectives and other advantages of the present invention can be realized and obtained through the following description. BRIEF DESCRIPTION OF THE DRAWINGS

[0024] In order to make the purpose, technical solutions and advantages of the present invention more clear, the present invention will be described in detail below in conjunction with the accompanying drawings, wherein:

[0025] Figure 1 It is a flow chart of the present invention. DETAILED DESCRIPTION

[0026] The following describes the embodiments of the present invention by specific examples, and those skilled in the art can easily understand other advantages and effects of the present invention from the contents disclosed in this specification. The present invention can also be implemented or applied through other different specific embodiments, and the details in this specification can also be modified or changed in various ways based on different viewpoints and applications without departing from the spirit of the present invention. It should be noted that the illustrations provided in the following embodiments only illustrate the basic concept of the present invention in a schematic manner, and the following embodiments and features in the embodiments can be combined with each other without conflict.

[0027] Among them, the drawings are only used for illustrative explanations, and they only represent schematic diagrams rather than actual pictures, and should not be understood as limitations on the present invention. In order to better illustrate the embodiments of the present invention, some parts of the drawings may be omitted, enlarged or reduced, and do not represent the size of actual products. For those skilled in the art, it is understandable that some well-known structures and their descriptions in the drawings may be omitted.

[0028] The same or similar numbers in the drawings of the embodiments of the present invention correspond to the same or similar parts; in the description of the present invention, it should be understood that if the terms "upper", "lower", "left", "right", "front", "rear", etc. indicate the orientation or position relationship, they are based on the orientation or position relationship shown in the drawings, which is only for the convenience of describing the present invention and simplifying the description, rather than indicating or implying that the device or element referred to must have a specific orientation, be constructed and operate in a specific orientation. Therefore, the terms describing the position relationship in the drawings are only used for illustrative purposes and cannot be understood as limiting the present invention. For ordinary technicians in this field, the specific meanings of the above terms can be understood according to specific circumstances.

[0029] See also Figure 1 , Example 1

[0030] This embodiment relates to a method and system for determining the composition of the bosh gas of a multi-media injection blast furnace. The method for calculating the composition of the bosh gas of a multi-media injection low-carbon blast furnace is performed according to the following steps:

[0031] Step 1: In this embodiment, the tuyere injection medium is air, coal powder (including coal injection carrier gas), coke oven gas, and oxygen. The components are shown in Table 1-Table 3. The coal injection carrier gas is N2, and the carrier gas ratio is 30kg / kgN2. The injection volume of air, coal powder, coke oven gas, and oxygen is 855m 3 / tHM, 131.3kg / tHM, 50m 3 / tHM、64m 3 / tHM.

[0032] Table 1 Air composition, volume fraction

[0033] project <![CDATA[O2]]> <![CDATA[N2]]> <![CDATA[H2O]]> unit ％ ％ ％ Numeric 21 78 1

[0034] Table 2 Composition of pulverized coal injected into blast furnace tuyere, mass percentage %.

[0035]

[0036] Table 3 Composition of coal gas injected into blast furnace tuyere, volume percentage %.

[0037] <![CDATA[CH4]]> <![CDATA[H2]]> CO <![CDATA[CO2]]> <![CDATA[N2]]> <![CDATA[H2O]]> 24.80 63.51 7.85 2.36 1.48 0.0

[0038] Step 2, the composition of the coke consumed in the blast furnace tuyere is shown in Table 4. According to the mass conservation of oxygen element before and after the reaction in the tuyere raceway, the amount of coke consumed in the tuyere raceway is calculated to be 223.65 kg / tHM.

[0039] Table 4 Composition of coke consumed at blast furnace tuyere, mass percentage.

[0040]

[0041] Step 3, the fixed carbon of pulverized coal combines with oxygen to generate CO, which enters the furnace bosh gas at a ratio of 80%, and the reduction rates of Fe2O3 and SiO2 in the ash are 6% and 100% respectively. Based on the pulverized coal composition, injection amount, C+O2=2CO, C+H2O=CO+H2, CnHm+n / 2O2=nCO+m / 2H2, CO2+C=2CO, SiO2+C=SiO+CO, Fe2O3+3C=3CO+2Fe, and the volatile matter of pulverized coal CO, H2, and N2 directly entering the furnace bosh gas, it can be calculated that the amount of furnace bosh gas generated by pulverized coal is 193.688m 3 / tHM, where H2, CO, N2 and SiO are 11.822, 180.080, 1.691 and 0.095m 3 / tHM.

[0042] Step 4: Calculate the amount of gas produced by the pulverized coal carrier gas from the coal injection amount and the carrier gas ratio to be 3.502m 3 / tHM.

[0043] Step 5: Based on the composition of coke oven gas, C+H2O=CO+H2, CnHm+n / 2O2=nCO+m / 2H2, CO2+C=2CO, and CO, H2, and N2 in the injection gas directly entering the bosh gas, the amount of bosh gas generated by the injection gas is calculated to be 75.980m 3 / tHM, where H2, CO, and N2 are 56.555, 18.685, and 0.740m 3 / tHM.

[0044] Step 6: Based on the air injection volume, composition, C+H2O=CO+H2 and the fact that N2 in the air directly enters the furnace bosh gas, the amount of furnace bosh gas generated by the injected air is calculated to be 686.143m 3 / tHM, of which H2, CO, and N2 are 8.837, 8.837, and 668.468m respectively 3 / tHM.

[0045] Step 7: The reduction rates of Fe2O3 and SiO2 in the ash of the coke consumed by the tuyere are 6% and 100% respectively. Based on the consumption of coke at the tuyere, the composition, C+O2=2CO, SiO2+C=SiO+CO, and Fe2O3+3C=3CO+2Fe, the amount of bosh gas generated by the coke consumed by the tuyere is calculated to be 332.683m 3 / tHM, of which CO and SiO are 332.392 and 0.291m 3 / tHM.

[0046] Step 8: Based on the gas volume calculated from Steps 3 to 7, the total amount of furnace gas can be calculated to be 1288.494m 3 / tHM, where H2, CO, N2 and SiO are 77.214, 539.995, 674.401 and 0.386m respectively 3 / tHM, and the volume fractions are 5.99%, 41.91%, 52.34% and 0.03% respectively.

[0047] Finally, it should be noted that the above embodiments are only used to illustrate the technical solution of the present invention rather than to limit it. Although the present invention has been described in detail with reference to the preferred embodiments, those skilled in the art should understand that the technical solution of the present invention can be modified or replaced by equivalents without departing from the purpose and scope of the technical solution, which should be included in the scope of the claims of the present invention.

Claims

1. A method for determining the composition of multi-media injection blast furnace bosh gas, characterized in that: The following steps are involved: S1 determines the type of injection medium for the blast furnace tuyere, and inputs the composition, injection amount and coke composition of each injection medium for the tuyere; S2 is calculated based on the mass conservation of oxygen before and after the reaction in the tuyere raceway, and the amount of coke consumed in the tuyere raceway; S3 According to the characteristics of the tuyere injection medium and the tuyere coke consumption, the coal gas after the reaction in the tuyere cyclotron zone is composed of four components: CO, N2, H2 and SiO. According to the Gass law, the contents of CO, N2, H2 and SiO converted from each injection medium and coke are calculated according to the composition and consumption of the tuyere injection medium and coke. S4 Calculate the content of each component of the bosh gas based on the content of CO, N2, H2 and SiO produced by each injection medium and coke; S5 Calculate the total amount of bosh gas and the proportion of each component based on the content of each component of the bosh gas.

2. The method for determining the composition of multi-media injection blast furnace bosh gas according to claim 1, characterized in that: The blast furnace tuyere blowing medium is one or more combinations of air, coal powder, CO-H2-CH4-rich reducing gas, and oxygen; the tuyere blowing medium sprays CO-H2-CH4-rich reducing gas, which is one or more of coke oven gas, natural gas, coalbed methane, converter gas decarbonization gas, Ouye furnace decarbonization gas, and blast furnace top decarbonization gas.

3. The method for determining the composition of multi-media injection blast furnace bosh gas according to claim 2, characterized in that: The components of the coal powder that can be converted into bosh gas mainly include coal powder fixed carbon, coal powder volatile matter, SiO2 and Fe2O3 in coal powder ash, and coal powder physical water; the components of the coke that can be converted into bosh gas mainly include coke fixed carbon, SiO2 and Fe2O3 in coke ash.

4. The method for determining the composition of multi-media injection blast furnace bosh gas according to claim 2, characterized in that: The fixed carbon in the pulverized coal combines with oxygen to generate CO, and the ratio of CO entering the furnace bosh gas is 60% to 100%, and the volatile matter is completely converted into CO, H2 and N2 and enters the furnace bosh gas.

5. The method for determining the composition of multi-media injection blast furnace bosh gas according to claim 2, characterized in that: The ratio of SiO2 in the coal powder and coke ash reduced to CO and SiO is between 0% and 50%.

6. The method for determining the composition of multi-media injection blast furnace bosh gas according to claim 2, characterized in that: The ratio of Fe2O3 in the coal powder and coke ash reduced to CO is between 50% and 100%.

7. The method for determining the composition of multi-media injection blast furnace bosh gas according to claim 2, characterized in that: All the oxygen in the air and the oxygen in the injection medium combine with the carbon in the coke, coal powder, and hydrocarbons in the injection gas to form CO and enter the furnace gas.

8. The method for determining the composition of multi-media injection blast furnace bosh gas according to claim 2, characterized in that: The component input of the coal powder in the tuyere injection medium includes industrial analysis components, coal powder ash components and coal powder volatile components.

9. The method for determining the composition of multi-media injection blast furnace bosh gas according to claim 1, characterized in that: The components of the air in the blast furnace tuyere injection medium that can be converted into bosh gas mainly include nitrogen and moisture.

10. The method for determining the composition of multi-media injection blast furnace bosh gas according to claim 1, characterized in that: The air component input in the tuyere spraying medium includes oxygen content, nitrogen content and humidity content.

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