A temperature control method for molten iron entering a KR desulfurization station

Abstract

The present invention belongs to the field of KR desulfurization methods, and relates to a temperature control method for molten iron entering a KR desulfurization station. The molten iron has a temperature drop due to turnover from a blast furnace to a KR station, and the turnover time varies, and the temperature drop varies. A handheld thermocouple is used to measure the temperature at a KR desulfurization station, and only plays a judgment role, that is, whether the molten iron temperature meets the desulfurization temperature requirement. The present invention simulates and calculates the temperature drop of molten iron from the blast furnace to the steelmaking KR desulfurization station according to a cooling model; judges whether the molten iron inlet temperature is greater than or equal to a preset desulfurization threshold. If the molten iron inlet temperature is less than the preset desulfurization threshold, it is adjusted in advance to make the molten iron inlet temperature greater than or equal to the preset desulfurization threshold. By establishing a temperature drop model, it can be pre-judged in advance according to the desulfurization temperature requirement, thereby optimizing the molten iron turnover and playing a guiding role in production.

Description

Technical Field

[0001] The invention belongs to the field of KR desulfurization methods and relates to a temperature control method for molten iron entering a KR desulfurization station. Background Art

[0002] KR (Kambara Reactor) desulfurization was invented by Nippon Steel in 1963 to limit the use of magnesium. It was applied to industrial production in 1965. The so-called KR desulfurization is to immerse the cross-shaped stirring head, which is cast with refractory materials and baked, into the molten pool of the molten iron ladle to a certain depth. The weighed desulfurizer is added to the surface of the molten iron by the feeder through the vortex generated by its rotation, and is drawn into the molten iron by the vortex to make the calcium oxide-based desulfurization powder fully contact and react with the molten iron to achieve the purpose of desulfurization.

[0003] In order to ensure that the molten iron temperature is sufficient, the fluidity is good, and the stirring desulfurization equipment is not damaged, the existing method is to first perform slag treatment after the molten iron tank enters the steelmaking KR desulfurization station, and then use a handheld thermocouple to measure the temperature. However, when the molten iron tank enters the KR station from the blast furnace, the temperature of the molten iron will drop due to the turnover process. Due to the different turnover times, the specific temperature drop values ​​will also change. The handheld thermocouple can only play a judgment role in measuring the temperature at the KR desulfurization station, that is, whether the molten iron temperature meets the desulfurization temperature requirements. When the molten iron temperature does not meet the desulfurization temperature requirements, it is too late to process it. It needs to be processed additionally after the desulfurization process is completed, which increases the labor and the cost of KR desulfurization. The desulfurization effect is also difficult to guarantee, which is easy to affect the subsequent process, thereby affecting the product quality. Summary of the invention

[0004] In view of this, the purpose of the present invention is to provide a temperature control method for molten iron entering a KR desulfurization station, to make advance predictions based on the desulfurization temperature requirements, and thereby optimize the molten iron turnover process and reduce the cost of KR desulfurization.

[0005] To achieve the above object, the present invention provides the following technical solutions: a temperature control method for molten iron entering a KR desulfurization station, which simulates and calculates the temperature drop of molten iron from blast furnace tapping to the steelmaking KR desulfurization station according to a temperature drop model;

[0006] The cooling model is:

[0007] Molten iron inlet temperature = blast furnace tapping temperature - 1.669 * iron receiving time - 0.35 * turnover time;

[0008] Determine whether the molten iron inlet temperature is greater than or equal to the preset desulfurization threshold. If not, adjust in advance to make the molten iron inlet temperature greater than or equal to the preset desulfurization threshold.

[0009] Furthermore, the blast furnace tapping temperature is between 1500-1600°C.

[0010] Furthermore, the preset desulfurization threshold is 1350°C.

[0011] Furthermore, the advance control adopts a first control strategy, which is to reduce the turnover time. During the turnover process, the molten iron can be preferentially transported to the KR desulfurization station for desulfurization by adjusting the turnover priority, so as to avoid excessive temperature drop during the turnover time.

[0012] Furthermore, it also includes checking whether the temperature of the molten iron entering the station is greater than the warning threshold. If not, the second control strategy is adopted to forcibly increase the temperature of the molten iron entering the station. When the temperature of the molten iron entering the station is close to the warning value, it may cause the molten iron to form crust, make it impossible to remove slag and desulfurize, affect the rhythm of steelmaking and increase production costs. This solution increases the temperature of the molten iron entering the station through forced intervention to avoid the above situation.

[0013] Furthermore, the warning threshold is 1250°C.

[0014] Furthermore, the second control strategy includes heat preservation treatment of the molten iron during the iron receiving process, for example, adding heat preservation ash to the molten iron tank.

[0015] Furthermore, the second control strategy also includes heating the molten iron before it enters the station. For example, the heavy tank of molten iron is transported to the baking position for heat preservation.

[0016] Glossary:

[0017] Iron receiving time: Iron receiving time refers to the time period from the beginning of iron receiving to the completion of iron receiving in the molten iron tank.

[0018] Turnaround time: Turnaround time refers to the period between the completion of iron receiving in the molten iron tank and the arrival at the KR station.

[0019] The beneficial effects of the present invention are:

[0020] The present invention introduces parameters such as blast furnace iron tapping temperature, iron receiving time, and average turnover time from blast furnace to KR station to form a cooling model. The theoretical temperature curve of molten iron entering the KR desulfurization station is basically consistent with the actual temperature curve. Errors exist in individual tanks due to differences in tank age and factors such as baking before iron receiving. The average absolute error is 6.9OC, and the average relative error is only 0.5%, which does not affect the accuracy of the model. The molten iron inlet temperature can be predicted more accurately, and it can be determined in advance whether the molten iron inlet temperature meets the desulfurization conditions, and targeted regulation can be carried out to timely increase the molten iron inlet temperature to meet the desulfurization conditions, thereby avoiding subsequent additional treatment, thereby ensuring the normal subsequent process and product quality, and saving additional treatment costs.

[0021] 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

[0022] 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:

[0023] Figure 1 This is a flow chart of a method according to Embodiment 1 of the present invention;

[0024] Figure 2 It is a line graph of the theoretical inlet temperature of molten iron and the actual inlet temperature. DETAILED DESCRIPTION

[0025] 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.

[0026] 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.

[0027] 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.

[0028] See also Figure 1-2, which is a temperature control method for molten iron entering a KR desulfurization station. The temperature drop of molten iron from blast furnace tapping to steelmaking KR desulfurization station is simulated and calculated according to a cooling model; whether the calculated molten iron inlet temperature is greater than or equal to a preset desulfurization threshold is determined. If the molten iron inlet temperature is less than the preset desulfurization threshold, the first control strategy is used to control in advance. By adjusting the turnover priority, the molten iron is preferentially transported to the KR desulfurization station for desulfurization, the turnover time is reduced, and the molten iron inlet temperature is greater than or equal to the preset desulfurization threshold; avoid excessive temperature drop due to the turnover time;

[0029] The cooling model is:

[0030] Molten iron inlet temperature = blast furnace tapping temperature - 1.669 * iron receiving time - 0.35 * turnover time;

[0031] Among them, the blast furnace iron tapping temperature ranges from 1500 to 1600°C, and the preset desulfurization threshold is 1350°C.

[0032] When judging the temperature of the molten iron entering the station, it also includes whether the temperature of the molten iron entering the station is greater than the warning threshold. If not, the second control strategy is adopted to forcibly increase the temperature of the molten iron entering the station. In this embodiment, the warning value is 1250°C. When the temperature of the molten iron entering the station is close to the warning value, it may cause the molten iron to form crusts, slag desulfurization cannot be removed, affect the rhythm of steelmaking and increase production costs. At this time, it is difficult to effectively improve the turnaround time by regulating the turnaround time. It is necessary to increase the temperature of the molten iron entering the station through forced intervention to avoid the above situation, including heat preservation or heating of the molten iron during the iron receiving process. For example, the heavy tank of molten iron is transported to the baking position for heat preservation.

[0033] In the present embodiment, when comprehensively judging the molten iron inlet temperature, if the calculated molten iron inlet temperature is between the warning value and the preset desulfurization threshold, only the first control strategy needs to be adopted. The range of molten iron inlet temperature that can be controlled by adjusting the turnover time is within 100°C. Therefore, reducing the turnover time can prevent the temperature from dropping too much. It should be noted that the iron-affecting time is a constant parameter and is only related to the steel material. The turnover time is generally long and is the main influencing factor of the molten iron temperature drop. There is no possibility that the molten iron inlet temperature will be lower than the warning value without turnover. If the temperature of the molten iron entering the station is less than the warning value and exceeds the temperature range that can be adjusted by adjusting the turnover time, then insulation ash can be added to the molten iron tank to reduce the temperature drop of the molten iron during the iron receiving process. This method is suitable for the temperature difference between the calculated molten iron entering the station and the warning value between 0 and 20 ° C. When the temperature difference between the calculated molten iron entering the station and the warning value is large, the molten iron is forced to heat up before the molten iron enters the station. For example, the heavy tank is baked and heated during the iron receiving process, so that the temperature will not drop during the iron receiving process, but will rise instead. At this time, the molten iron temperature can be detected by thermocouples after the iron receiving is completed, and the calculation method of the molten iron entering the station temperature is changed to the molten iron temperature at the end of the iron receiving minus the temperature reduced during the turnover process. According to the calculation method at this time, recalculate whether the molten iron entering the station temperature is greater than the preset desulfurization temperature. If so, no additional intervention is required. If not, the molten iron entering the station temperature can be adjusted by reducing the turnover time to meet the requirements.

[0034] 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 controlling the temperature of molten iron entering a KR desulfurization station, characterized in that: According to the temperature drop model, the temperature drop of molten iron from the blast furnace to the steelmaking KR desulfurization station is simulated and calculated; The cooling model is: Molten iron inlet temperature = blast furnace tapping temperature - 1.669 * iron receiving time - 0.35 * turnover time, where iron receiving time refers to the time period from the start of iron receiving to the completion of iron receiving in the molten iron tank, and turnover time refers to the time period from the completion of iron receiving in the molten iron tank to the entry into the KR station; Determine whether the temperature of the molten iron entering the station is greater than or equal to the preset desulfurization threshold. If not, adjust in advance to make the temperature of the molten iron entering the station greater than or equal to the preset desulfurization threshold; The advance control adopts a first control strategy, and the first control strategy is to reduce the turnaround time; It also includes judging whether the temperature of the molten iron entering the station is greater than the warning threshold, and if not, adopting the second control strategy to forcibly increase the temperature of the molten iron entering the station; The second control strategy includes heat preservation treatment of molten iron during the iron receiving process; The second control strategy also includes heating the molten iron before it enters the station.

2. The temperature control method for molten iron entering a KR desulfurization station according to claim 1, characterized in that: The blast furnace tapping temperature is between 1500-1600°C.

3. The temperature control method for molten iron entering a KR desulfurization station according to claim 2, characterized in that: The preset desulfurization threshold is 1350°C.

4. The temperature control method for molten iron entering a KR desulfurization station according to claim 3, characterized in that: The warning threshold is 1250°C.

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