Intelligent control method and system for mixed grinding of coarse iron ore by vertical mill

Abstract

The invention discloses an intelligent control method for mixing and grinding coarse iron ore by a vertical mill, which comprises the following steps: judging whether the running current of a hopper elevator and a belt conveyor is within a first threshold range or not, and if not, adjusting the return quantity according to a first set period until the running current is within the first threshold range; whether the drying outlet temperature is within a second threshold range or not is judged, and if not, the opening degree of the gas valve is adjusted according to a second set period; judging whether the negative pressure of the combustion chamber is within a third threshold range or not, and if not, adjusting the opening degree of the electric butterfly valve of the circulating air door according to a third set period; and whether the difference value between the grinding roller pressure and the set value is larger than a difference threshold value or not is judged, and if yes, the grinding roller pressure is adjusted through the hydraulic system till the grinding roller pressure is within a fourth threshold value range. According to the invention, through a multi-parameter cooperative control mechanism, adjustability of dynamic balance and core parameters of the system is realized.

Description

Technical Field

[0001] The present invention relates to the technical field, and in particular to an intelligent control method and system for mixed grinding of coarse iron ore by a vertical mill. Background Art

[0002] The vertical dry-grinding iron ore system is a highly efficient and energy-saving process that integrates crushing, drying, grinding, grading, and conveying. It is particularly suitable for iron ore beneficiation applications where water is scarce or water consumption needs to be reduced. Its core equipment is a vertical mill, which achieves dry grinding through mechanical grinding and airflow separation.

[0003] Vertical dry-grinding iron ore systems grind a wide variety of iron ore powders with widely varying properties, such as Indonesian, Turkish, and Spanish limonite, all coarse-grained iron ores. During production, the simultaneous grinding of these various powders, combined with significant variations in moisture content, particle size, and grindability, results in significant mill vibration, a high failure rate, low grinding efficiency, and high energy consumption. Furthermore, frequent manual adjustments to various equipment parameters are required, leading to a high rate of operational errors. Summary of the Invention

[0004] The technical problem to be solved by the present invention is to overcome the shortcomings of the prior art and provide an intelligent control method and system for mixed grinding of coarse iron ore by a vertical mill.

[0005] In order to solve the above technical problems, the technical solutions of the present invention are as follows: An intelligent control method for mixed grinding of coarse iron ore in a vertical mill, comprising: Obtaining the operating current of the return hopper elevator and the belt conveyor, and determining whether the operating current is within a first threshold range; if not, adjusting the return material amount according to a first set period until the operating current is within the first threshold range; Obtain the drying outlet temperature and determine whether it is within the second threshold range. If not, adjust the gas valve opening according to the second set period, and obtain the gas flow rate change and the combustion chamber inlet temperature change after each adjustment. If the gas flow rate change is greater than or equal to the first change threshold or the combustion chamber inlet temperature change is greater than or equal to the second change threshold, pause the adjustment within a preset time T, and determine whether the drying outlet temperature is within the second threshold range after the preset time T. If not, repeat this step until the drying outlet temperature is within the second threshold range. Obtaining the combustion chamber negative pressure and determining whether it is within a third threshold range; if not, adjusting the opening of the circulating air door electric butterfly valve according to a third set period; Obtain the roller pressure of the grinding roller, and determine whether the difference between the roller pressure and the set value is greater than the difference threshold. If so, adjust the roller pressure of the grinding roller through the hydraulic system until it is within the fourth threshold range.

[0006] As a preferred embodiment of the intelligent control method for mixed grinding of coarse iron ore by a vertical mill according to the present invention, the method of obtaining the operating current of the return hopper elevator and the belt conveyor and determining whether the operating current is within a first threshold range, and if not, adjusting the return material amount according to a first set period until the operating current is within the first threshold range includes: Obtain the operating current of the return hopper elevator and the belt conveyor, and determine whether the operating current of the return hopper elevator is within the range of 55~60A and whether the operating current of the belt conveyor is within the range of 12.5~13.5A. If not, adjust the return material amount every 20s until the operating current is within the range of 55~60A.

[0007] As a preferred solution of the intelligent control method for mixed grinding of coarse iron ore by a vertical mill according to the present invention, the return material amount is adjusted by adjusting the speed of the powder concentrator, and the adjustment amount is ±20rpm.

[0008] As a preferred embodiment of the intelligent control method for mixed grinding of coarse iron ore by a vertical mill according to the present invention, the method further comprises: obtaining the drying outlet temperature and judging whether it is within the second threshold range; if not, adjusting the gas valve opening according to a second set period, and obtaining the gas flow rate change value and the combustion chamber inlet temperature change value after each adjustment; if the gas flow rate change value is greater than the first change threshold value or the combustion chamber inlet temperature change value is greater than or equal to the second change threshold value, pausing the adjustment within a preset time T, and judging whether the drying outlet temperature is within the second threshold range after the preset time T; if not, repeating this step until the drying outlet temperature is within the second threshold range, including: Obtain the drying outlet temperature and determine whether it is within the range of 99-101°C. If not, adjust the gas valve opening with a second set period of 50 seconds and an adjustment amount of ± (2-5%). After each adjustment, obtain the change in gas flow rate and combustion chamber inlet temperature. If the change in gas flow rate is greater than or equal to 1000 m³ / h or the change in combustion chamber inlet temperature is greater than or equal to 2°C, pause the adjustment within 30 seconds and determine whether the drying outlet temperature is within the range of 99-101°C after 30 seconds. If not, repeat this step until the drying outlet temperature is within the range of 99-101°C.

[0009] As a preferred embodiment of the intelligent control method for mixed grinding of coarse iron ore by a vertical mill according to the present invention, the method of obtaining the negative pressure of the combustion chamber and determining whether it is within a third threshold range, and if not, adjusting the opening degree of the circulating air door electric butterfly valve according to a third set period includes: Obtain the negative pressure of the combustion chamber and determine whether it is in the range of -200~-80Pa. If not, adjust the opening degree of the circulating air door electric butterfly valve every 10s, and the adjustment amount of the circulating air door electric butterfly valve opening degree each time is ±1%.

[0010] As a preferred embodiment of the intelligent control method for mixed grinding of coarse iron ore by a vertical mill according to the present invention, the steps of obtaining the roller pressure of the grinding roller and determining whether the difference between the roller pressure of the grinding roller and a set value is greater than a difference threshold value, and if not, adjusting the roller pressure of the grinding roller by a hydraulic system until the roller pressure is within a fourth threshold value range includes: Obtain the roller pressure and determine whether the difference between it and the set value is greater than 0.2 MPa. If so, adjust the roller pressure through the hydraulic system until it is within the range of 6.8~7.2 MPa.

[0011] The present invention also provides an intelligent control system for a vertical mill for mixed grinding of coarse iron ore, comprising: A first control module is configured to obtain the operating current of the return hopper elevator and the belt conveyor, determine whether the operating current is within a first threshold range, and if not, adjust the return material amount according to a first set period until the operating current is within the first threshold range; The second control module is used to obtain the drying outlet temperature and determine whether it is within the second threshold range. If not, the gas valve opening is adjusted according to the second set period, and the gas flow rate change value and the combustion chamber inlet temperature change value are obtained after each adjustment. If the gas flow rate change value is greater than or equal to the first change threshold or the combustion chamber inlet temperature change value is greater than or equal to the second change threshold, the adjustment is suspended within a preset time T, and it is determined whether the drying outlet temperature is within the second threshold range after the preset time T. If not, this step is repeated until the drying outlet temperature is within the second threshold range; a third control module, configured to obtain the combustion chamber negative pressure and determine whether it is within a third threshold range; if not, adjusting the opening of the circulating air door electric butterfly valve according to a third set period; The fourth control module is used to obtain the roller pressure of the grinding roller and determine whether the difference between the roller pressure and the set value is greater than the difference threshold. If so, the roller pressure of the grinding roller is adjusted by the hydraulic system until it is within the fourth threshold range.

[0012] The beneficial effects of the present invention are: (1) The present invention realizes the dynamic balance of the system and the adjustability of core parameters through a multi-parameter collaborative control mechanism. It has been verified in production that under the same working conditions, the parameters of each device can be accurately adjusted by putting it into automatic production operation, and the operator does not need to intervene manually to adjust, thus achieving the automatic operation effect and the purpose of transformation.

[0013] (2) The present invention automatically sets production parameters based on real-time operating conditions and automatically controls the operation of the above equipment, achieving continuous and stable production goals. Under the same operating conditions, automatic operation is more accurate and timely than manual operation, with higher production efficiency, lower energy consumption, and better production process stability. BRIEF DESCRIPTION OF THE DRAWINGS

[0014] In order to more clearly illustrate the technical solutions of the embodiments of the present invention, the following briefly introduces the drawings required for use in the description of the embodiments. 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 any creative labor.

[0015] Figure 1 This is the process flow chart of vertical dry grinding production. DETAILED DESCRIPTION

[0016] In order to make the contents of the present invention more clearly understood, the present invention is further described below in detail based on specific implementation methods in conjunction with the accompanying drawings.

[0017] Vertical dry grinding production process flow chart Figure 1 During the production process, vertical mills are subject to fluctuations in blast furnace gas pressure, drying temperature, material moisture content, return material volume, and roller pressure. To ensure continuous and efficient mill operation and controlled powder quality, frequent manual intervention is required to adjust various grinding system parameters. However, manual operation at full capacity inevitably leads to lags and low predictive accuracy.

[0018] To this end, the present embodiment provides an intelligent control method for mixed grinding of coarse iron ore in a vertical mill. Initial operating parameters are set as follows: During the feeding and production phase, the vertical mill system operates according to the following baseline parameters: roller pressure: 7.0 MPa; classifier speed: 280 rpm; main exhaust fan frequency: 36 Hz; mill drying outlet temperature: 100°C; combustion chamber negative pressure: -100 Pa. Subsequently, the automatic control parameter setting ranges are shown in Table 1, and the actuator control ranges are shown in Table 2.

[0019]

[0020] Table 1

[0021] Table 2 The intelligent control method for mixing and grinding coarse iron ore in a vertical mill specifically comprises the following steps: Step S101: Obtain the operating current of the return hopper elevator and the belt conveyor, determine whether the operating current of the return hopper elevator is within the range of 55~60A and whether the operating current of the belt conveyor is within the range of 12.5~13.5A. If not, adjust the return material amount every 20s until the operating current is within the range of 55~60A.

[0022] It should be noted that the method for adjusting the return material amount is to adjust the speed of the powder classifier, and the adjustment amount is ±20rpm.

[0023] Step S102: Obtain the drying outlet temperature and determine whether it is within the range of 99-101°C. If not, adjust the gas valve opening with a second set period of 50 seconds, with an adjustment amount of ±(2-5%). After each adjustment, obtain the change in gas flow rate and combustion chamber inlet temperature. If the change in gas flow rate is greater than or equal to 1000 m³ / h or the change in combustion chamber inlet temperature is greater than or equal to 2°C, pause the adjustment within 30 seconds and determine whether the drying outlet temperature is within the range of 99-101°C after 30 seconds. If not, repeat this step until the drying outlet temperature is within the range of 99-101°C.

[0024] Step S103: Obtain the combustion chamber negative pressure and determine whether it is in the range of -200~-80Pa. If not, adjust the opening degree of the circulating air door electric butterfly valve every 10s, and the adjustment amount of the circulating air door electric butterfly valve opening degree each time is ±1%.

[0025] Step S104: Obtain the roller pressure, and determine whether the difference between the roller pressure and the set value is greater than 0.2 MPa. If so, adjust the roller pressure through the hydraulic system until it is within the range of 6.8 to 7.2 MPa.

[0026] In addition, an embodiment of the present application further provides an intelligent control system for a vertical mill for mixed grinding of coarse iron ore, the system comprising: a first control module, a second control module, a third control module, and a fourth control module.

[0027] Among them, the first control module is used to obtain the operating current of the return hopper elevator and the belt conveyor, and determine whether it is within the first threshold range. If not, the return material amount is adjusted according to the first set period until the operating current is within the first threshold range.

[0028] The second control module is used to obtain the drying outlet temperature and determine whether it is within the second threshold range. If not, the gas valve opening is adjusted according to the second set period, and the gas flow change value and the combustion chamber inlet temperature change value are obtained after each adjustment. If the gas flow change value is greater than or equal to the first change threshold or the combustion chamber inlet temperature change value is greater than or equal to the second change threshold, the adjustment is suspended within the preset time T, and it is determined whether the drying outlet temperature is within the second threshold range after the preset time T. If not, this step is repeated until the drying outlet temperature is within the second threshold range.

[0029] The third control module is used to obtain the negative pressure of the combustion chamber and determine whether it is within a third threshold range. If not, the opening degree of the circulating air door electric butterfly valve is adjusted according to a third set period.

[0030] The fourth control module is used to obtain the roller pressure of the grinding roller and determine whether the difference between the roller pressure and the set value is greater than the difference threshold. If so, the roller pressure of the grinding roller is adjusted by the hydraulic system until it is within the fourth threshold range.

[0031] The above technical solution achieves dynamic balance of the system through a multi-parameter collaborative control mechanism. The core parameters can be adjusted (such as control cycle and amplitude). After production verification, under the same working conditions, by putting it into automatic production operation, the parameters of each equipment are accurately adjusted, and the operator does not need manual intervention to adjust, thus achieving the automatic operation effect and the purpose of transformation.

[0032] The design capacity of a vertical mill in a certain factory is 4 million tons. According to the current annual output of 900,000 tons, under the same production conditions, the blast furnace gas consumption per ton of ore can be reduced by 19 m when the automatic control system is used compared with manual operation. 3 The cost reduction benefit per ton of ore = 19m³ / t*780kcal / m³*4.186 / 1,000,000*39.75 yuan / GJ = 2.5 yuan / t. The annual cost reduction benefit is: 2.5*90 = 2.25 million yuan / year.

[0033] Therefore, the technical solution of this application automatically sets production parameters based on real-time operating conditions and automatically controls the operation of the above equipment, achieving continuous and stable production goals. Under the same operating conditions, automatic operation is more accurate and timely than manual operation, with higher production efficiency, lower energy consumption, and better production process stability.

[0034] In addition to the above embodiments, the present invention may also have other implementation methods; any technical solutions formed by equivalent replacement or equivalent transformation fall within the protection scope required by the present invention.

Claims

1. An intelligent control method for vertical mill mixed grinding of coarse iron ore, characterized by: include: Obtaining the operating current of the return hopper elevator and the belt conveyor, and determining whether the operating current is within a first threshold range; if not, adjusting the return material amount according to a first set period until the operating current is within the first threshold range; Obtain the drying outlet temperature and determine whether it is within the second threshold range. If not, adjust the gas valve opening according to the second set period, and obtain the gas flow rate change and the combustion chamber inlet temperature change after each adjustment. If the gas flow rate change is greater than or equal to the first change threshold or the combustion chamber inlet temperature change is greater than or equal to the second change threshold, pause the adjustment within a preset time T, and determine whether the drying outlet temperature is within the second threshold range after the preset time T. If not, repeat this step until the drying outlet temperature is within the second threshold range. Obtaining the combustion chamber negative pressure and determining whether it is within a third threshold range; if not, adjusting the opening of the circulating air door electric butterfly valve according to a third set period; Obtain the roller pressure of the grinding roller, and determine whether the difference between the roller pressure and the set value is greater than the difference threshold. If so, adjust the roller pressure of the grinding roller through the hydraulic system until it is within the fourth threshold range.

2. The intelligent control method for mixed grinding of coarse iron ore by a vertical mill according to claim 1, characterized in that: The obtaining of the operating current of the return hopper elevator and the belt conveyor, and determining whether the operating current is within a first threshold range, and if not, adjusting the return material amount according to a first set period until the operating current is within the first threshold range includes: Obtain the operating current of the return hopper elevator and the belt conveyor, and determine whether the operating current of the return hopper elevator is within the range of 55~60A and whether the operating current of the belt conveyor is within the range of 12.5~13.5A. If not, adjust the return material amount every 20s until the operating current is within the range of 55~60A.

3. The intelligent control method for mixed grinding of coarse iron ore by a vertical mill according to claim 2, characterized in that: The return material amount is adjusted by adjusting the speed of the powder concentrator, and the adjustment amount is ±20rpm.

4. The intelligent control method for mixed grinding of coarse iron ore in a vertical mill according to claim 1, characterized in that: The step of obtaining the drying outlet temperature and determining whether it is within the second threshold range, and if not, adjusting the gas valve opening according to a second set period, and obtaining a gas flow rate change value and a combustion chamber inlet temperature change value after each adjustment, and pausing the adjustment within a preset time T if the gas flow rate change value is greater than the first change threshold value or the combustion chamber inlet temperature change value is greater than or equal to the second change threshold value, and determining whether the drying outlet temperature is within the second threshold range after the preset time T, and if not, repeating this step until the drying outlet temperature is within the second threshold range includes: Obtain the drying outlet temperature and determine whether it is within the range of 99-101°C. If not, adjust the gas valve opening with a second set period of 50 seconds and an adjustment amount of ± (2-5%). After each adjustment, obtain the change in gas flow rate and combustion chamber inlet temperature. If the change in gas flow rate is greater than or equal to 1000 m³ / h or the change in combustion chamber inlet temperature is greater than or equal to 2°C, pause the adjustment within 30 seconds and determine whether the drying outlet temperature is within the range of 99-101°C after 30 seconds. If not, repeat this step until the drying outlet temperature is within the range of 99-101°C.

5. The intelligent control method for mixed grinding of coarse iron ore by a vertical mill according to claim 1, characterized in that: The obtaining of the combustion chamber negative pressure and determining whether the negative pressure is within a third threshold range, and if not, adjusting the opening of the circulating air door electric butterfly valve according to a third set period includes: Obtain the negative pressure of the combustion chamber and determine whether it is in the range of -200~-80Pa. If not, adjust the opening degree of the circulating air door electric butterfly valve every 10s, and the adjustment amount of the circulating air door electric butterfly valve opening degree each time is ±1%.

6. The intelligent control method for mixed grinding of coarse iron ore in a vertical mill according to claim 1, characterized in that: The step of obtaining the roller pressure of the grinding roller and determining whether the difference between the roller pressure of the grinding roller and the set value is greater than a difference threshold, and if not, adjusting the roller pressure of the grinding roller by the hydraulic system until the roller pressure is within a fourth threshold range includes: Obtain the roller pressure and determine whether the difference between it and the set value is greater than 0.2 MPa. If so, adjust the roller pressure through the hydraulic system until it is within the range of 6.8~7.2 MPa.

7. An intelligent control system for vertical mill mixed grinding of coarse iron ore, characterized by: include: A first control module is configured to obtain the operating current of the return hopper elevator and the belt conveyor, determine whether the operating current is within a first threshold range, and if not, adjust the return material amount according to a first set period until the operating current is within the first threshold range; The second control module is used to obtain the drying outlet temperature and determine whether it is within the second threshold range. If not, the gas valve opening is adjusted according to the second set period, and the gas flow rate change value and the combustion chamber inlet temperature change value are obtained after each adjustment. If the gas flow rate change value is greater than or equal to the first change threshold or the combustion chamber inlet temperature change value is greater than or equal to the second change threshold, the adjustment is suspended within a preset time T, and it is determined whether the drying outlet temperature is within the second threshold range after the preset time T. If not, this step is repeated until the drying outlet temperature is within the second threshold range; a third control module, configured to obtain the combustion chamber negative pressure and determine whether it is within a third threshold range; if not, adjusting the opening of the circulating air door electric butterfly valve according to a third set period; The fourth control module is used to obtain the roller pressure of the grinding roller and determine whether the difference between the roller pressure and the set value is greater than the difference threshold. If so, the roller pressure of the grinding roller is adjusted by the hydraulic system until it is within the fourth threshold range.

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