Method for calculating bayan obo iron ore concentrate and blast furnace fuel ratio correspondence by using operation line expansion

Abstract

The invention discloses a method for calculating bayan obo iron ore concentrate and blast furnace fuel ratio correspondence by using operation line expansion, which effectively combines blast furnace operation line calculation with a corresponding relationship between a proportion of bayan obo iron ore concentrate entering a steel-coated blast furnace and a blast furnace fuel ratio. The method comprises the following steps: finding out periods of different in-furnace self-produced ore proportions of a certain blast furnace through big data arrangement, simultaneously satisfying background conditions that furnace charge structures and operation systems are similar, obtaining actual results of ideal fuel ratios and ideal gas utilization rates in an ideal state according to an operation line calculation method, and combining the influence relationship between the blast furnace gas utilization rates and the fuel ratios to obtain the optimal fuel ratio of the blast furnace. And the ideal gas utilization rates under different conditions are regressed to the same numerical value, and according to the fuel ratio difference value and the furnace-entering self-produced ore difference value under different conditions, the corresponding relation between the furnace-entering bayan obo iron ore concentrate proportion and the blast furnace fuel ratio is calculated. According to the method, the corresponding relation between the proportion of the Bayan obo iron ore concentrate fed into the steel-clad blast furnace and the fuel ratio of the blast furnace is detected, a quantitative concept is formed, and an advance is provided for subsequent adjustment of operators.

Description

Technical Field

[0001] The invention belongs to the technical field of ironmaking blast furnace smelting, and in particular relates to a method for calculating the correspondence between the ratio of Bayan Obo iron concentrate and blast furnace fuel by using operating line expansion. Background Art

[0002] The Ri st operating line was proposed by Professor A. Ri st of France in the 1960s. It is a rectangular coordinate line diagram that studies the internal connection and law between blast furnace smelting parameters and indicators. In this century, with the continuous advancement of blast furnace smelting technology, the operating line algorithm has also been changed and improved many times, and the calculation accuracy is more in line with current production needs. The operating line can quantitatively describe the process of "oxygen migration" in the blast furnace with "line segments" in a two-dimensional rectangular coordinate system, that is, the process of oxygen brought into the blast furnace by iron ore and blast air migrating to the coal gas. At the same time, the chemical equilibrium point and thermal equilibrium point of the reaction in the furnace can be obtained by calculating the positions of point W and point P, and finally the reasonable adjustment of the blast furnace condition and the reduction of energy consumption can be achieved.

[0003] Since the Bayan Obo iron concentrate has high K, Na, F, and S contents, and also has the smelting properties of "easy to melt, easy to condense, and difficult to remelt", the Baosteel blast furnace generally has low air volume, low kinetic energy, and poor gas utilization compared with the blast furnaces of benchmark enterprises in the industry. In recent years, through continuous improvement of the system and long-term technological research, the gap between the economic indicators of Baosteel blast furnace and the industry has been narrowing year by year, but the impact of the Bayan Obo iron concentrate on the blast furnace fuel ratio has never been quantitatively characterized, causing the operator to lag in adjustment, which in turn affects the furnace condition. How to establish a corresponding relationship between the proportion of Bayan Obo iron concentrate entering the furnace and the blast furnace fuel ratio has become a technical problem that the Baosteel blast furnace operators urgently need to solve. Summary of the invention

[0004] The purpose of the present invention is to provide a method for calculating the correspondence between the ratio of Bayan Obo iron concentrate and blast furnace fuel by expanding the operating line, systematically exploring the correspondence between the ratio of Bayan Obo iron concentrate entering the Baotou Steel blast furnace and the ratio of blast furnace fuel, forming a quantitative concept, and preparing in advance for subsequent adjustments by operators, so as to avoid the adverse effects such as abnormal furnace conditions caused by excessively high ratio of Bayan Obo iron concentrate entering the furnace.

[0005] In order to solve the above technical problems, the present invention adopts the following technical solutions:

[0006] The present invention discloses a method for calculating the correspondence between the ratio of the Bayan Obo iron concentrate and the blast furnace fuel by using an operating line expansion, effectively combining the calculation of the blast furnace operating line with the corresponding relationship between the ratio of the Bayan Obo iron concentrate fed into the Baosteel blast furnace and the blast furnace fuel ratio, finding the periods of different ratios of self-produced ore fed into a blast furnace through big data sorting, and satisfying the background conditions of similar charge structure and operating system at the same time, then obtaining the actual results of the ideal fuel ratio and the ideal gas utilization rate under the ideal state according to the operating line calculation method, and then regressing the ideal gas utilization rate under different conditions to the same value in combination with the influence relationship between the blast furnace gas utilization rate and the fuel ratio, and finally calculating the corresponding relationship between the ratio of the Bayan Obo iron concentrate fed into the furnace and the blast furnace fuel ratio according to the difference of the fuel ratio and the difference of the self-produced ore fed into the furnace under different conditions:

[0007] 1). Calculation of actual operating lines A, E points, and ideal operating lines A′, E′;

[0008] 2). Calculation of the corresponding relationship between blast furnace gas utilization rate and fuel ratio;

[0009] 3). Calculation of the corresponding relationship between the ratio of Bayan Obo iron ore concentrate entering the furnace and the blast furnace fuel ratio.

[0010] Furthermore, a blast furnace with an effective volume of 3000m 3 According to the previous data, we found the periods with different proportions of self-produced ore entering the blast furnace, and selected two periods of 37.4% and 50.6%. Both periods met the conditions of stable furnace conditions, similar charge structure and system adjustments.

[0011] Furthermore, the amount of carbon burned before the tuyere Cb is calculated based on the total amount of oxygen brought into the blast furnace by blast air. 2 The content is 21%, the oxygen purity is 98%, and the calculated Cb is 325.7kg / t, Cg is 372.3kg / t, and Vg is 1550.6m 3 / t,η H2 It is 41%, and then the subtraction method is used to calculate the coordinates of point A as (1.4543, 1.3718), the coordinates of point E as (0, -1.4717), and the PW ideal operating line is constructed. The coordinates of A′ in the ideal operating line are (1.4946, 1.3718), and the coordinates of E′ are (0, -1.4188).

[0012] Furthermore, the theoretical fuel ratio, also known as the ideal fuel ratio of the blast furnace, is the lowest fuel ratio in the blast furnace smelting process. The theoretical fuel ratio is represented by ΔK, and its calculation formula is: Δμ in the formula is the difference between the slope of the actual operation line of the blast furnace and the slope of the ideal operation line. When the proportion of self-produced ore entering the furnace is 37.4%, the coke saving potential of the blast furnace is 21kg / t, and the theoretical fuel ratio is 509.8kg / t. At the same time, using the ideal operation line equation yA′E′=1.8672x-1.4188, the maximum gas utilization rate of the blast furnace can be obtained, that is, ηco optimal=(XA′-1)*100=49.46%.

[0013] According to the above calculation results, assuming that a 3000m 3 CO and CO in blast furnace gas 2 The sum of the volume fractions of remains unchanged, then the horizontal coordinate of point A on the ideal operating line is Calculated φ′(CO 2 )=22.17%, then Δφ(CO 2 )=1.8%,after converted to 1% gas utilization rate, the fuel ratio is affected to 6.45kg / t.

[0014] Furthermore, the same deduction method is used to calculate that under the condition of 50.6% of the self-produced ore entering the furnace, the coordinates of point A are (1.4575, 1.3776), and the coordinates of point E are (0, -1.518), and the PW ideal operating line is constructed, and the coordinates of A' in the ideal operating line are (1.493, 1.378), and the coordinates of E' are (0, -1.470). Under the above conditions, the coke saving potential of the blast furnace under the condition of 50.6% of the self-produced ore entering the furnace is calculated to be 18.9kg / t, and the theoretical fuel ratio is 516.7kg / t; the optimal ηco is 49.3% obtained by using the ideal operating line equation.

[0015] Furthermore, increasing the proportion of self-produced ore by 1 percentage point will affect the fuel ratio of the blast furnace to 0.44kg / t.

[0016] Furthermore, this method can be used to iterate the data in the future, and then find out the impact range of 1 percentage point of self-produced ore ratio on the blast furnace fuel ratio.

[0017] Compared with the prior art, the beneficial technical effects of the present invention are:

[0018] At present, due to the many factors affecting the Bayan Obo iron concentrate in the blast furnace production process, the influence of the amount of Bayan Obo iron concentrate entering the furnace on the blast furnace fuel ratio has never been able to be quantitatively characterized, and the operators are unable to make reasonable adjustments at the first time when the amount entering the furnace increases. Most of them make judgments based on experience, which results in a large deviation in the adjustment range and a lag in the adjustment time. In severe cases, it causes furnace condition fluctuations. The idea of ​​the present invention can clarify the quantitative influence of the proportion of Bayan Obo iron concentrate entering the furnace on the blast furnace fuel ratio under different blast furnaces under different production conditions, so as to timely reduce the changes in furnace conditions caused by the above-mentioned influences through upper and lower adjustments. DETAILED DESCRIPTION

[0019] The present invention will be further described below in conjunction with examples.

[0020] The effective volume of a blast furnace of Baotou Steel is 3000m3. According to the previous data, different periods of self-produced ore proportions were found in the blast furnace. The present invention selects two periods of 37.4% and 50.6%, which both meet the conditions of stable furnace conditions, similar charge structure and system adjustment. Specific parameters are shown in the table below.

[0021] Table 13000m 3 Production parameters and indicators of blast furnaces with a 37.4% self-produced ore ratio

[0022]

[0023] Table 23000m 3 Composition of top gas in blast furnace with 37.4% self-produced ore in the furnace

[0024]

[0025] Table 33000m 3 The composition of pig iron in blast furnace with 37.4% self-produced ore as input, %

[0026]

[0027]

[0028] First, the amount of carbon burned before the tuyere Cb is calculated based on the total amount of oxygen brought into the blast furnace by blast. 2 The content is 21%, the oxygen purity is 98%, and the calculated Cb is 325.7kg / t, Cg is 372.3kg / t, and Vg is 1550.6m 3 / t,η H2 It is 41%, and then the subtraction method is used to calculate the coordinates of point A as (1.4543, 1.3718), the coordinates of point E as (0, -1.4717), and the PW ideal operating line is constructed. The coordinates of A′ in the ideal operating line are (1.4946, 1.3718), and the coordinates of E′ are (0, -1.4188).

[0029] The theoretical fuel ratio is also the ideal fuel ratio of the blast furnace, which is the lowest fuel ratio in the blast furnace smelting process. The theoretical fuel ratio is represented by ΔK, and its calculation formula is: Δμ in the formula is the difference between the slope of the actual operation line of the blast furnace and the slope of the ideal operation line. When the proportion of self-produced ore entering the furnace is 37.4%, the coke saving potential of the blast furnace is 21kg / t, and the theoretical fuel ratio is 509.8kg / t. At the same time, using the ideal operation line equation yA′E′=1.8672x-1.4188, the maximum gas utilization rate of the blast furnace can be obtained, that is, ηco optimal=(XA′-1)*100=49.46%.

[0030] According to the above calculation results, assuming that a 3000m 3 CO and CO in blast furnace gas 2 The sum of the volume fractions of remains unchanged, then the horizontal coordinate of point A on the ideal operating line is Calculated φ′(CO 2 )=22.17%, then Δφ(CO 2 )=1.8%,after converted to 1% gas utilization rate, the fuel ratio is affected to 6.45kg / t.

[0031] Similarly, the selected 50.6% self-produced ore ratio entering the furnace is calculated, and the parameters used are shown in the table below.

[0032] Table 53000m 3 Production parameters and indicators of blast furnace under the condition of 50.6% self-produced ore proportion

[0033]

[0034] Table 63000m 3 Composition of top gas in blast furnace with 50.6% self-produced ore in the furnace

[0035]

[0036] Table 73000m 3 The composition of pig iron in blast furnace with 50.6% self-produced ore, %

[0037]

[0038] Table 83000m 3 The composition of slag in blast furnace with 50.6% self-produced ore in the furnace, %

[0039]

[0040] Similarly, the deduction method is used to calculate that under the condition of 50.6% of self-produced ore entering the furnace, the coordinates of point A are (1.4575, 1.3776), and the coordinates of point E are (0, -1.518). The PW ideal operating line is constructed, and the coordinates of A' in the ideal operating line are (1.493, 1.378), and the coordinates of E' are (0, -1.470). Under the above conditions, the coke saving potential of the blast furnace under the condition of 50.6% of self-produced ore entering the furnace is calculated to be 18.9kg / t, and the theoretical fuel ratio is 516.7kg / t. The optimal ηco is obtained by using the ideal operating line equation to be 49.3%.

[0041] The corresponding relationship is established for the above calculation results, see Table 9 for details.

[0042] Table 73000m 3 Blast furnace under different proportions of self-produced ore

[0043]

[0044] From the table above, we can see that the difference in the proportion of self-produced ore in the two periods is 13.2%. The maximum gas utilization rate of 49.46% under the condition of 37.4% is converted to 49.3%, corresponding to the theoretical fuel ratio of 510.9kg / t. The calculation formula is [509.8-(49.3-49.46)*6.45*100]. In this way, the difference in the theoretical fuel ratio of the two periods is 5.8kg / t. Then, increasing the proportion of self-produced ore by 1 percentage point will affect the fuel ratio of the blast furnace by 0.44kg / t. This method can be used for data iteration in the future to find out the influence range of 1 percentage point of self-produced ore proportion on the blast furnace fuel ratio.

[0045] The embodiments described above are only descriptions of the preferred modes of the present invention, and are not intended to limit the scope of the present invention. Without departing from the design spirit of the present invention, various modifications and improvements made to the technical solutions of the present invention by ordinary technicians in this field should all fall within the protection scope determined by the claims of the present invention.

Claims

1. A method for calculating the correspondence between the ratio of Bayan Obo iron ore concentrate and blast furnace fuel by using operating line expansion, characterized in that: The calculation of the blast furnace operation line and the corresponding relationship between the proportion of Bayan Obo iron ore concentrate entering the Baosteel blast furnace and the blast furnace fuel ratio are effectively combined. Through big data sorting, the periods of different proportions of self-produced ore entering a blast furnace are found, while the background conditions of similar charge structure and operation system are met. Then, the actual results of the ideal fuel ratio and ideal gas utilization rate under ideal conditions are obtained according to the operation line calculation method. Combined with the influence relationship between blast furnace gas utilization rate and fuel ratio, the ideal gas utilization rate under different conditions is regressed to the same value. Finally, according to the difference in fuel ratio and the difference in self-produced ore entering the furnace under different conditions, the corresponding relationship between the proportion of Bayan Obo iron ore concentrate entering the furnace and the blast furnace fuel ratio is calculated: 1). Calculation of actual operating lines A, E points, and ideal operating lines A′, E′; 2). Calculation of the corresponding relationship between blast furnace gas utilization rate and fuel ratio; 3). Calculation of the corresponding relationship between the ratio of Bayan Obo iron ore concentrate entering the furnace and the blast furnace fuel ratio.

2. The method for calculating the correspondence between the ratio of Bayan Obo iron ore concentrate and blast furnace fuel by using the operating line expansion according to claim 1 is characterized in that: The effective volume of a blast furnace is 3000m 3 According to the previous data, we found the periods with different proportions of self-produced ore entering the blast furnace, and selected two periods of 37.4% and 50.6%. Both periods met the conditions of stable furnace conditions, similar charge structure and system adjustments.

3. The method for calculating the correspondence between the ratio of Bayan Obo iron ore concentrate and blast furnace fuel by using operating line expansion according to claim 2 is characterized in that: First, the amount of carbon burned before the tuyere Cb is calculated based on the total amount of oxygen brought into the blast furnace by blast. The O2 content in the air is 21%, and the oxygen purity is 98%. The calculated Cb is 325.7kg / t, Cg is 372.3kg / t, and Vg is 1550.6m 3 / t,η H2 It is 41%, and then the subtraction method is used to calculate the coordinates of point A as (1.4543, 1.3718), the coordinates of point E as (0, -1.4717), and the PW ideal operating line is constructed. The coordinates of A′ in the ideal operating line are (1.4946, 1.3718), and the coordinates of E′ are (0, -1.4188).

4. The method for calculating the correspondence between the ratio of Bayan Obo iron ore concentrate and blast furnace fuel by using operating line expansion according to claim 3 is characterized in that: The theoretical fuel ratio is also the ideal fuel ratio of the blast furnace. It is the lowest fuel ratio in the blast furnace smelting process. The theoretical fuel ratio is represented by ΔK, and its calculation formula is: Δμ in the formula is the difference between the slope of the actual operation line of the blast furnace and the slope of the ideal operation line; when the proportion of self-produced ore entering the furnace is 37.4%, the coke saving potential of the blast furnace is 21kg / t, and the theoretical fuel ratio is 509.8kg / t; at the same time, using the ideal operation line equation yA′E′=1.8672x-1.4188, the maximum gas utilization rate of the blast furnace can be obtained, that is, ηco optimal=(XA′-1)*100=49.46%; According to the above calculation results, assuming that a 3000m 3 The sum of the volume fractions of CO and CO2 in the blast furnace gas remains unchanged, so the horizontal coordinate of point A on the ideal operating line is The calculation shows that φ′(CO2)=22.17%, then Δφ(CO2)=1.8%. After converting to 1% gas utilization, the fuel ratio is affected to 6.45kg / t.

5. The method for calculating the correspondence between the ratio of Bayan Obo iron ore concentrate and blast furnace fuel by using operating line expansion according to claim 1, characterized in that: The same deduction method is used to calculate that under the condition of 50.6% self-produced ore entering the furnace, the coordinates of point A are (1.4575, 1.3776), and the coordinates of point E are (0, -1.518). The PW ideal operating line is constructed, and the coordinates of A′ in the ideal operating line are (1.493, 1.378), and the coordinates of E′ are (0, -1.470); based on the above conditions, the coke saving potential of the blast furnace under the condition of 50.6% self-produced ore entering the furnace is calculated to be 18.9 kg / t, and the theoretical fuel ratio is 516.7 kg / t; the ideal operating line equation is used to obtain the optimal ηco of 49.3%.

6. The method for calculating the correspondence between the ratio of Bayan Obo iron ore concentrate and blast furnace fuel by using operating line expansion according to claim 1 or 5, characterized in that: Increasing the proportion of self-produced ore by 1 percentage point will affect the fuel ratio of the blast furnace to 0.44kg / t.

7. The method for calculating the correspondence between the ratio of Bayan Obo iron ore concentrate and blast furnace fuel by using operating line expansion according to claim 6 is characterized in that: This method can be used to iterate the data later, and then find out the impact range of 1 percentage point of self-produced ore ratio on the blast furnace fuel ratio.

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