Method and system for reducing fuel ratio of blast furnace

Abstract

The invention relates to a method and system for reducing the fuel ratio of a blast furnace. The method comprises the steps that tuyere design parameters of a target blast furnace are obtained; constructing a target function according to the tuyere design parameters of the target blast furnace; solving the target function to obtain the optimal depth of the tuyere circulation area of the target blast furnace; and adjusting the tuyere circulation area depth of the target blast furnace to the optimal depth so as to reduce the blast furnace fuel ratio. By adjusting the depth of the tuyere circulation area, airflow distribution in the blast furnace can be improved, the combustion efficiency of fuel is improved, and fuel consumption is reduced.

Description

Technical Field

[0001] The invention relates to the technical field of blast furnaces, and in particular to a method and system for reducing the fuel ratio of a blast furnace. Background Art

[0002] In the steel production process, the blast furnace is an important smelting equipment, and its fuel ratio directly affects the production cost and energy efficiency. Traditionally, coke is mainly used as fuel in blast furnace smelting, which is accompanied by a large amount of heat energy consumption and carbon dioxide emissions. With the global emphasis on environmental protection and sustainable use of resources, reducing the fuel ratio of blast furnaces and improving energy efficiency have become urgent needs in the industry. Summary of the invention

[0003] To solve the above problems, an object of the embodiments of the present invention is to provide a method and system for reducing the fuel ratio of a blast furnace.

[0004] A method for reducing the fuel ratio of a blast furnace, comprising:

[0005] Obtain the tuyere design parameters of the target blast furnace;

[0006] Constructing an objective function based on the tuyere design parameters of the target blast furnace;

[0007] Solving the objective function to obtain the optimal depth of the tuyere circulation zone of the target blast furnace;

[0008] The depth of the tuyere circulation zone of the target blast furnace is adjusted to the optimal depth to reduce the blast furnace fuel ratio.

[0009] Preferably, the objective function is:

[0010]

[0011] Among them, L represents the optimal depth of the tuyere circulation zone of the target blast furnace, D represents the furnace diameter, and E k represents the kinetic energy of the air blast, M represents the injection fuel ratio, and n represents the number of air outlets.

[0012] The present invention also provides a system for reducing the fuel ratio of a blast furnace, comprising:

[0013] A design parameter acquisition module, used to obtain the tuyere design parameters of the target blast furnace;

[0014] An objective function building module, used to build an objective function according to the tuyere design parameters of a target blast furnace;

[0015] An optimal depth solving module, used for solving the objective function to obtain the optimal depth of the tuyere circulation zone of the target blast furnace;

[0016] The blast furnace fuel ratio reduction module is used to adjust the depth of the tuyere circulation zone of the target blast furnace to an optimal depth to reduce the blast furnace fuel ratio.

[0017] According to the specific embodiments provided by the present invention, the present invention discloses the following technical effects:

[0018] The invention relates to a method for reducing the fuel ratio of a blast furnace. Compared with the prior art, the invention can improve the airflow distribution in the blast furnace, improve the combustion efficiency of the fuel and reduce the fuel consumption by adjusting the depth of the tuyere circulation zone.

[0019] In order to make the above-mentioned objects, features and advantages of the present invention more obvious and easy to understand, preferred embodiments are given below and described in detail with reference to the accompanying drawings. BRIEF DESCRIPTION OF THE DRAWINGS

[0020] In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the drawings required for use in the embodiments or the description of the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying creative work.

[0021] Figure 1 A schematic diagram of a method for reducing the fuel ratio of a blast furnace provided by the present invention;

[0022] Figure 2 This is a comparison chart of the blast parameters before and after adjustment provided by the present invention. DETAILED DESCRIPTION

[0023] In the description of the present invention, it should be understood that the terms "center", "longitudinal", "lateral", "length", "width", "thickness", "up", "down", "front", "back", "left", "right", "vertical", "horizontal", "top", "bottom", "inside", "outside", "clockwise", "counterclockwise" and the like indicate orientations or positional relationships based on the orientations or positional relationships shown in the accompanying drawings, and are only for the convenience of describing the present invention and simplifying the description, rather than indicating or implying that the referred device or element must have a specific orientation, be constructed and operated in a specific orientation, and therefore should not be understood as limiting the present invention.

[0024] In addition, the terms "first" and "second" are used for descriptive purposes only and should not be understood as indicating or implying relative importance or implicitly indicating the number of the indicated technical features. Therefore, the features defined as "first" and "second" may explicitly or implicitly include one or more of the features. In the description of the present invention, the meaning of "plurality" is two or more, unless otherwise clearly and specifically defined.

[0025] In the present invention, unless otherwise clearly specified and limited, the terms "installed", "connected", "connected", "fixed" and the like should be understood in a broad sense, for example, it can be a fixed connection, a detachable connection, or an integral connection; it can be a mechanical connection or an electrical connection; it can be a direct connection, or it can be an indirect connection through an intermediate medium, or it can be the internal communication of two components. For ordinary technicians in this field, the specific meanings of the above terms in the present invention can be understood according to specific circumstances.

[0026] See also Figure 1 , a method for reducing the fuel ratio of a blast furnace, comprising:

[0027] Step 1: Obtain the tuyere design parameters of the target blast furnace;

[0028] Step 2: Construct the objective function according to the tuyere design parameters of the target blast furnace;

[0029] In step 2, the objective function is:

[0030]

[0031] Among them, L represents the optimal depth of the tuyere circulation zone of the target blast furnace, D represents the furnace diameter, and E k represents the kinetic energy of the air blast, M represents the injection fuel ratio, and n represents the number of air outlets.

[0032] Step 3: Solving the objective function to obtain the optimal depth of the tuyere circulation zone of the target blast furnace;

[0033] Step 4: Adjust the depth of the tuyere circulation zone of the target blast furnace to the optimal depth to reduce the blast furnace fuel ratio.

[0034] The present invention further illustrates the method for reducing the blast furnace fuel ratio of the present invention in conjunction with specific embodiments below:

[0035] The adjustment of the air supply system is mainly achieved by selecting appropriate parameters such as wind speed and blast kinetic energy to make the initial gas flow distribution reasonable, the furnace work evenly and actively, the heat sufficient and stable, extend the furnace condition time, improve gas utilization, and reduce the blast furnace fuel ratio.

[0036] At present, the empirical equation of the length of the turning zone and the kinetic energy of the wind is:

[0037] ① Existing technology 1 blast furnace (volume 4063m 3 ) The furnace diameter is 13.4m, and the blast kinetic energy is 125000J·s- 1 , the length of the tuyere turning zone L is 1.8m, corresponding to the length of the tuyere turning zone L and the kinetic energy of the blast E k The empirical equation is:

[0038] D = 0.88 + 0.29 × 10 4 E k -0.37×10 -3 OIL·K / n Formula 1

[0039] Where:

[0040] D—furnace diameter, m

[0041] E k —Blowing kinetic energy, kg·m·s -1

[0042] OIL—injection amount, L·h -1

[0043] K—factor, used when coal injection

[0044] n—number of tuyere,

[0045] ② Existing technology 2 blast furnace (volume 2000m 3 ) The length of the tuyere swirl zone L and the kinetic energy of the blast E k The empirical equation of the relationship is:

[0046] D = 0.88 + 0.29 × 10- 2 E k -0.0176M / n Formula 2

[0047] Where:

[0048] D—furnace diameter, m

[0049] E k —Blowing kinetic energy, kg·m·s -1

[0050] M—injection fuel ratio, kg·tHM -1

[0051] n—number of tuyere,

[0052] Correction of empirical equation of raceway length and blast kinetic energy:

[0053] In the empirical equations of the whirlpool length and the blast kinetic energy provided by prior art 1 and prior art 2, 0.88 is a constant term and does not need to be corrected. The influence of the spray on the calculation result of the whirlpool length is very small (0.08% to 4.14%, i.e., 0.001m to 0.060m), and will not be discussed here. The coefficient of the blast kinetic energy has the greatest influence on the calculation result. In the two equations provided by prior art 1 and prior art 2, the coefficient term of the blast kinetic energy needs to be corrected.

[0054] According to formula 1, the length of the blast furnace tuyere raceway in prior art 1 is L = 1.80 m, and the blast kinetic energy Ek is calculated as 2.58 × 10 8 J.s -1 , and the actual blast energy provided is 125000J·s -1 There is a big difference. Both the value and order of magnitude of the kinetic energy coefficient of the blast are wrong here.

[0055] Prior art 2 does not provide the blast kinetic energy E of the relevant blast furnace. k and the data of the raceway length L, here we will use Baosteel 8 # Substituting the blast furnace kinetic energy into equation 2 for verification, the blast kinetic energy is 8792 kg·m·s -1 When the tuyere raceway length L is 26.32m, it is more than twice the furnace diameter. Obviously, Kun Steel's empirical equation is also wrong. The empirical equation of the raceway length and blast kinetic energy is corrected as follows.

[0056] According to the data of the blast furnace in the prior art 1, D = 1.8m, E k =125kJ·s -1 =12775kg·m·s -1 , substituting into formula 1, ignoring the influence of the blowing term, the kinetic energy coefficient a of the blast can be calculated as:

[0057] a=(1.8-0.88) / E k =0.721×10 -4 Formula 3

[0058] Combining equation 2 and equation 3, the empirical formula of the length of the turning zone and the kinetic energy of the wind is corrected:

[0059] D = 0.88 + 0.72 × 10 -4 E k -0.0176M / n Formula 4

[0060] Where:

[0061] D—furnace diameter, m

[0062] E k —Blowing kinetic energy, kg·m·s -1

[0063] M—injection fuel ratio, kg·tHM -1

[0064] n—number of tuyere,

[0065] According to the ironmaking production technical manual, when the area of ​​the annular zone formed by the tuyere vortex zone reaches 50% of the total area of ​​the furnace, the optimal tuyere vortex zone length, the optimal initial gas flow distribution and the lowest fuel ratio can be obtained. The corresponding blast kinetic energy can be taken as the optimal blast kinetic energy, and the corresponding air volume and wind speed can be taken as the optimal air volume and wind speed.

[0066] When the annular area formed by the tuyere raceway reaches 50% of the total furnace area, the furnace diameter D and the tuyere raceway length L meet [D 2 -(D-2L) 2 ] / D 2 = 50%, the blast furnace can obtain the best initial gas distribution and fuel ratio, from which it can be inferred that 8 # The best depth L of blast furnace is:

[0067]

[0068] Where:

[0069] D—furnace diameter, steel 8 # The diameter of the blast furnace hearth is 12.60m;

[0070] L—Deepness of air circulation area, m

[0071] Calculation shows that Baosteel 8 # The optimal depth of the blast furnace tuyere raceway zone is 1.85m.

[0072] Make 8 # The blast kinetic energy corresponding to the blast furnace tuyere raceway length reaching 1.85m can be regarded as the optimal blast kinetic energy. According to formula 5, it can be calculated that Baosteel 8 # When the length of the blast furnace raceway is 1.85 m, the appropriate blast kinetic energy is 13402 kg·m·s -1 , i.e. 131.34 kJ·s -1 , the blast furnace fuel ratio can be reduced by 12.90kg·tHM -1 .

[0073] Table 1 Air supply parameters before adjustment

[0074]

[0075] Table 2 Adjusted air supply parameters

[0076]

[0077] After the optimal depth of the blast furnace tuyere raceway is adjusted, the air supply system parameters are adjusted from Table 1 to Table 2. Among them, the diameter of the tuyere used in the 8# blast furnace is 0.13m and 0.12m. Due to the limitation of the tuyere spare parts, the most suitable tuyere area cannot be achieved. Therefore, the tuyere area is only increased from 0.475m2 Expanded to 0.496m 2 . Adjustment of other air supply parameters: air volume from 6444m 3 ·min -1 Increased to 7123m 3 ·min-1, coal injection amount from 55.30t·tHM -1 Increased to 57.11t·tHM -1 The wind temperature increased from 1185℃ to 1200℃, and the humidification increased from 3.39g·m -3 Increased to 12.34 g·m -3 .

[0078] Blast furnace gas flow parameters change as follows Figure 2 As shown in the figure, when the air volume increases significantly, the pressure difference (ΔP) decreases from 0.216Mpa to 0.208Mpa, a decrease of 0.008Mpa, a decrease of 3.70%. The pressure-volume relationship is significantly improved, and the kinetic energy of the blast (E k ) from 9700kg·m·s -1 Increased to 12103 kg·m·s -1 , an increase of 2403kg·m·s -1 , an increase of 24.77%, improved the working condition of the tuyere whirlpool area, increased the gas utilization rate from 42.08% to 44.38%, and it is expected that the blast furnace fuel ratio can be reduced by 12.90kg·tHM -1 .

[0079] The present invention also provides a system for reducing the fuel ratio of a blast furnace, comprising:

[0080] A design parameter acquisition module, used to obtain the tuyere design parameters of the target blast furnace;

[0081] An objective function building module, used to build an objective function according to the tuyere design parameters of a target blast furnace;

[0082] An optimal depth solving module, used for solving the objective function to obtain the optimal depth of the tuyere circulation zone of the target blast furnace;

[0083] The blast furnace fuel ratio reduction module is used to adjust the depth of the tuyere circulation zone of the target blast furnace to an optimal depth to reduce the blast furnace fuel ratio.

[0084] According to the specific embodiments provided by the present invention, the present invention discloses the following technical effects:

[0085] The invention relates to a method for reducing the fuel ratio of a blast furnace. Compared with the prior art, the invention can improve the airflow distribution in the blast furnace, improve the combustion efficiency of the fuel and reduce the fuel consumption by adjusting the depth of the tuyere circulation zone.

[0086] The above is only a specific embodiment of the present invention, but the protection scope of the present invention is not limited thereto. Any technical solution that can be easily thought of by a person skilled in the art within the technical scope disclosed by the present invention should be included in the protection scope of the present invention. Therefore, the protection scope of the present invention shall be based on the protection scope of the claims.

Claims

1. A method for reducing the fuel ratio of a blast furnace, characterized in that: include: Obtain the tuyere design parameters of the target blast furnace; Constructing an objective function based on the tuyere design parameters of the target blast furnace; Solving the objective function to obtain the optimal depth of the tuyere circulation zone of the target blast furnace; The depth of the tuyere circulation zone of the target blast furnace is adjusted to the optimal depth to reduce the blast furnace fuel ratio.

2. A method for reducing the fuel ratio of a blast furnace according to claim 1, characterized in that: The objective function is: Among them, L represents the optimal depth of the tuyere circulation zone of the target blast furnace, D represents the furnace diameter, and E k represents the kinetic energy of the air blast, M represents the injection fuel ratio, and n represents the number of air outlets.

3. A system for reducing the fuel ratio of a blast furnace, characterized in that: include: A design parameter acquisition module, used to obtain the tuyere design parameters of the target blast furnace; An objective function building module, used to build an objective function according to the tuyere design parameters of a target blast furnace; An optimal depth solving module, used for solving the objective function to obtain the optimal depth of the tuyere circulation zone of the target blast furnace; The blast furnace fuel ratio reduction module is used to adjust the depth of the tuyere circulation zone of the target blast furnace to an optimal depth to reduce the blast furnace fuel ratio.

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