Method for correcting tank weight of injection tank of blast furnace coal injection system

Abstract

The invention discloses a method for correcting the tank weight of an injection tank of a blast furnace coal injection system. The method comprises the following steps: establishing a mathematical model according to an initial value of filled pulverized coal, a value of just starting injection after pressurization, injection time and an injection rate; calculating a pulverized coal weight value in the injection process according to the mathematical model; comparing the weight value of the pulverized coal after injection and pressure relief with the weight value of the pulverized coal after injection; and correcting the model according to a comparison result. According to the method, a mathematical model is established by combining parameters such as an initial value of loaded pulverized coal, a value of just starting injection after pressurization, injection time, injection rate and the like, a pulverized coal weight value in an injection process is calculated, values after injection and pressure relief are compared with values after injection, and the model is corrected, so that a more accurate model is obtained; and high-precision injection is further realized.

Description

Technical Field

[0001] The invention relates to a method for correcting the weight of a coal injection tank in a blast furnace coal injection system. Background Art

[0002] The coal injection system is one of the important links in blast furnace production. Its uniform injection is an important assessment indicator of the coal injection system, and the accuracy of the injection tank weight detection directly affects the injection effect. At present, most domestic injection systems use the original injection tank weight to represent the weight of coal powder, and ignore the influence of nitrogen in the injection tank on the weight, which causes detection errors, thus affecting the accuracy of coal injection and further realizing high-precision injection. Summary of the invention

[0003] In order to overcome the above-mentioned defects, the object of the present invention is to provide a method for correcting the weight of a blast furnace coal injection system injection tank.

[0004] To achieve the above object, a method for correcting the weight of a blast furnace coal injection system injection tank of the present invention comprises the following steps:

[0005] A mathematical model is established based on the initial value after the pulverized coal is loaded, the value at the beginning of the injection after the pressure is completed, the injection time, and the injection rate;

[0006] Calculating the weight value of the pulverized coal during the injection process according to the mathematical model;

[0007] Compare the weight of the pulverized coal after the injection is completed and the pressure relief is completed with the weight of the pulverized coal when the injection is completed;

[0008] The model is modified based on the comparison results.

[0009] Furthermore, the mathematical model is:

[0010] W m =W 0 -f[t,X t , S.P. b ]-F(P) (1)

[0011] Among them, W 0 Detect the original tank weight for the spray tank, W m is the weight of coal powder in the injection tank; f[t, X t , S.P. b ] is the tank weight affected by nitrogen during the injection process, where t is the injection time, X t is the average blowing rate at time t during the blowing period, SP bis the benchmark injection rate; F(P) is the tank weight affected by nitrogen pressure, P is the set tank pressure, the unit is kPa, for the same injection, its value is constant, that is, the weight of the pulverized coal at the time of injection and the weight of the pulverized coal at the start of pressurization, F(p) = the weight of the injection tank when the system starts to inject - the initial value of the injection tank after the pulverized coal is loaded.

[0012] Furthermore, the X t The calculation formula is:

[0013] X t＝ (SP 1 +SP 2 +SP 3 +…+SPt) / t (2).

[0014] Furthermore, the method further comprises: t , S.P. b ]Do the following:

[0015] f[t,X t , S.P. b ]=[a*X t / SP b +b]*t (3)

[0016] Formula (1) is equivalent to:

[0017] W m =W 0 -a[(SP 1 +SP 2 +SP 3 +…+SPt) / t-SP b ]*tb*t-W3+W2 (4)

[0018] Where a and b are adjustment coefficients, which should be corrected according to the actual situation on site.

[0019] Furthermore, the correction step includes:

[0020] The weight of the coal powder calculated according to formula (4) is W4. After the pressure relief is completed, the weight of the pure coal powder is W6, and the error err = W4-W6;

[0021] Take M groups of blowing data to perform model correction (t, err), and obtain the average blowing time of M groups as tM, the error average value errM, and the correction coefficient bM=errM / tM; M is a positive integer greater than 1.

[0022] If the absolute value of bM is greater than 100kg, it is corrected according to b=b+bM, and the value of b is limited to 0 <b<3x10 -4 .

[0023] If the absolute value of bM is less than 100kg, no correction is performed.

[0024] The present invention establishes a mathematical model based on the initial value after the coal powder is loaded, the value at the beginning of the injection after the pressure is completed, the injection time, the injection rate and other parameters to calculate the weight value of the coal powder in the injection process. The value after the injection is completed and the pressure relief is completed is compared with the value when the injection is completed, and the model is corrected to obtain a more accurate model, thereby further realizing high-precision injection. BRIEF DESCRIPTION OF THE DRAWINGS

[0025] Figure 1 This is the timing diagram of tank weight change. DETAILED DESCRIPTION

[0026] The embodiments of the present invention are described in detail below with reference to the accompanying drawings.

[0027] In the description of the present invention, it should be understood that the terms "center", "up", "down", "front", "back", "left", "right", "vertical", "horizontal", "top", "bottom", "inside", "outside", etc., indicating the orientation or position relationship are based on the orientation or position relationship shown in the drawings, and are 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 operated in a specific orientation, and therefore cannot be understood as a limitation on the present invention.

[0028] 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. Thus, a feature defined as "first" or "second" may explicitly or implicitly include one or more of the features. In the description of the present invention, unless otherwise specified, "plurality" means two or more.

[0029] In the description of the present invention, it should be noted that, unless otherwise clearly specified and limited, the terms "installed", "connected", and "connected" 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 direct connection, or 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.

[0030] The invention discloses a method for correcting the weight of a blowing tank in a blast furnace coal injection system, comprising a weighing sensor, a blowing tank pressure detection transmitter, and a blowing valve, a pressure compensation valve, and a pressure relief valve normally configured in the system.

[0031] The normal production process is as follows:

[0032] Step 1: Add powder

[0033] Step 2: Pressurization

[0034] Step 3: Blowing (pressurizing at the same time, and controlling the pressure at a stable value)

[0035] Step 4: After the spraying is completed, the pressure is released and then the next cycle is entered.

[0036] Under normal circumstances, the tank weight change sequence diagram is as follows: Figure 1 As shown:

[0037] At t1, coal loading begins, and at t2, coal loading is completed. At this time, the tank weight is W2, which is at normal pressure and is the weight of pure coal powder. Nitrogen is then added to the injection tank to achieve the tank pressure required for injection. When the system starts to spray, the weight of the injection tank is W3, and W3 includes the weight of nitrogen and the tank weight error caused by its pressure properties. During the injection process, the coal powder content becomes less and less. In order to maintain the stability of the tank pressure, nitrogen needs to be added to the injection tank. Therefore, the subsequent tank weight includes the weight of coal powder and the weight caused by nitrogen and pressure (different from the W3 moment). When the injection is completed, the original tank weight is W5, and the tank weight calculated by the model is W4. After the pressure relief is completed, the tank weight at this time is W6. According to multiple sets of data (W4, W6), the model is corrected until the difference between W4 and W6 is within the allowable error range.

[0038] Embodiment 1:

[0039] like Figure 1 The following is the timing diagram of the tank weight change:

[0040] At t1, coal loading begins, and at t2, coal transfer is completed. At this time, the tank weight is W2, which is the weight of pure coal powder at normal pressure. After that, nitrogen is added to the injection tank to reach the required tank pressure, and the injection is waiting. When the system starts to inject, the weight of the injection tank is W3, and at this time, W3 includes the weight of nitrogen and the tank weight error caused by its pressure properties. During the injection process, the coal powder content is getting less and less. In order to maintain the stability of the tank pressure, nitrogen needs to be added to the injection tank. Therefore, the tank weight detected later includes the weight of coal powder and nitrogen, as well as the error caused by nitrogen pressure. When the injection is completed, the original tank weight is W5, and the tank weight calculated by the model is W4. After the pressure relief is completed, the tank weight at this time is W6. The injection cycle of the present invention is one hour, and the tank weight unit is tons.

[0041] During the spraying process: W m =W 0 -f[t,X t , S.P. b ]-F(P) Formula (1)

[0042] Where W 0 Detect the original tank weight for the spray tank, Wm is the weight of coal powder in the injection tank; f[t, X t , S.P. b ] is the tank weight affected by nitrogen during the injection process, where t is the injection time, X t is the average blowing rate at time t during the blowing period, SP b is the benchmark injection rate; F(P) is the tank weight affected by nitrogen pressure, P is the set tank pressure, the unit is kPa, and its value is constant for the same injection, that is, the difference between the coal powder weight at the injection time and the coal powder weight at the start of pressurization, F(p) = W3-W2.

[0043] X t＝ (SP 1 +SP 2 +SP 3 +…+SPt) / t Formula (2)

[0044] For f[t, X t , S.P. b ]Do the following processing:

[0045] f[t,X t , S.P. b ]=[a*X t / SP b +b]*t Formula (3)

[0046] Formula (1) is equivalent to:

[0047] W m =W 0 -a[(SP 1 +SP 2 +SP 3 +…+SPt) / t-SP b ]*tb*t-W3+W2 Formula (4)

[0048] Where a and b are adjustment coefficients, which can be modified according to the actual situation on site.

[0049] The present invention estimates the value of a. Assuming that under a certain working condition, the tank pressure is set to 1000 kPa, the coal powder density is 0.7 kg / m3, the nitrogen density is 1.25 kg / m3, and the coal powder is filled with 35 tons. The local standard atmospheric pressure is 101 kPa, and the injection rate is 35 t / h, then a = (P + 101.1) * 1.25 * W2 / 101.1 * 0.7 * 1000 * 3600 = 2.x10 -4 .

[0050] When the injection is completed, the weight of the coal powder calculated according to formula (4) is W4. After the pressure relief is completed, the weight of the pure coal powder is W6. Then the error err = W4-W6.

[0051] Take M groups of blowing data to perform model correction (t, err). Here, 20 groups are taken as an example. The average blowing time of the 20 groups is t20, and the average error is err20. The correction coefficient b20 = err20 / t20.

[0052] If the absolute value of b20 is greater than 100kg, it is corrected according to b=b+b20, and the value of b is limited to 0 <b<3x10 -4 .

[0053] If the absolute value of b20 is less than 100kg, no correction is performed.

[0054] The present invention is described in detail above in conjunction with the accompanying drawings, but the present invention is not limited to the above embodiments, and various changes can be made within the knowledge of ordinary technicians in the field without departing from the purpose of the present invention. Many other changes and modifications that do not depart from the concept and scope of the present invention should be regarded as the protection scope of the present invention.

[0055] In the description of this specification, specific features, structures, materials or characteristics may be combined in an appropriate manner in any one or more embodiments or examples.

[0056] The above is only a specific embodiment of the present invention, but the protection scope of the present invention is not limited thereto. Any person skilled in the art can easily think of changes or substitutions within the technical scope disclosed by the present invention, which should be included in the protection scope of the present invention. Therefore, the protection scope of the present invention should be based on the protection scope of the claims.

Claims

1. A method for correcting the weight of a blast furnace coal injection system injection tank, characterized in that: The method comprises the following steps: A mathematical model is established based on the initial value after the pulverized coal is loaded, the value at the beginning of the injection after the pressure is completed, the injection time, and the injection rate; Calculating the weight value of the pulverized coal during the injection process according to the mathematical model; Compare the weight of the pulverized coal after the injection is completed and the pressure relief is completed with the weight of the pulverized coal when the injection is completed; The model is modified based on the comparison results.

2. The method for correcting the weight of the injection tank of the blast furnace coal injection system according to claim 1, characterized in that: The mathematical model is: W m =W0-f[t,X t ,SP b ]-F(P) (1) Among them, W0 is the original tank weight of the spray tank, W m is the weight of coal powder in the injection tank; f[t, X t , S.P. b ] is the tank weight affected by nitrogen during the injection process, where t is the injection time, X t is the average blowing rate at time t during the blowing period, SP b is the benchmark injection rate; F(P) is the tank weight affected by nitrogen pressure, P is the set tank pressure, the unit is kPa, for the same injection, its value is constant, that is, the weight of the pulverized coal at the time of injection and the weight of the pulverized coal at the start of pressurization, F(p) = the weight of the injection tank when the system starts to inject - the initial value of the injection tank after the pulverized coal is loaded.

3. The method for correcting the weight of the injection tank of the blast furnace coal injection system according to claim 1, characterized in that: The X t The calculation formula is: X t＝ (SP1+SP2+SP3+…+SPt) / t (2)。 4. The method for correcting the weight of the injection tank of the blast furnace coal injection system according to claim 1, characterized in that: The method further comprises: t , S.P. b ]Do the following: f[t,X t ,SP b ]=[a*X t / SP b +b]*t (3) Formula (1) is equivalent to: W m =W0-a[(SP1+SP2+SP3+…+SPt) / t-SP b ]*t-b*t-W3+W2 (4) Where a and b are adjustment coefficients, which should be corrected according to the actual situation on site.

5. The method for correcting the weight of the injection tank of the blast furnace coal injection system according to claim 1, characterized in that: The correction steps include: The weight of the coal powder calculated according to formula (4) is W4. After the pressure relief is completed, the weight of the pure coal powder is W6, and the error err = W4-W6; Take M groups of blowing data to perform model correction (t, err), and obtain the average blowing time of M groups as tM, the error average value errM, and the correction coefficient bM=errM / tM; M is a positive integer greater than 1. If the absolute value of bM is greater than 100kg, it is corrected according to b=b+bM, and the value of b is limited to 0 <b<3x10 -4 . If the absolute value of bM is less than 100kg, no correction is performed.

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