Control method for argon-oxygen refining ferrochrome carbon content based on expert internal model control

Abstract

The invention relates to a control method for an argon-oxygen refining ferrochrome carbon content based on expert internal model control, and relates to the technical field of Argon oxygen decarburization (AOD) furnace refining low-carbon ferrochromium alloys. According to the method, when an internal model control model is built, a form of a given filter is defined, the filter is serially connected into the internal model control model, a building method of a filter time constant expert control system is particularly given, and the filter time constant expert control system can be used for building and evaluating a filter time constant with a best performance and is used for automatically optimizing and adjusting the filter time constant in an internal model controller in the whole smelting process. According to the control method for the argon-oxygen refining ferrochrome carbon content based on the expert internal model control provided by the invention, the influence of external unmeasured disturbance on the whole smelting process can be effectively overcome, and the steady-state zero-deflection accurate control on a terminal carbon content is realized; and a heat balance equation in an AOD furnace smelting process can be accurately built, and an accurate relationship between a molten pool temperature change rate and a gas supply speed is obtained, so that the smelting efficiency of the argon-oxygen refining low-carbon ferrochromium alloy is improved.

Description

technical field [0001] The invention relates to the technical field of refining low-carbon ferrochrome alloys with an AOD furnace, in particular to a method for controlling the carbon content of ferrochrome in argon-oxygen refining based on expert internal model control. Background technique [0002] In the process of argon-oxygen refining of low-carbon ferrochromium alloys, carbon element C, chromium element Cr and silicon element Si participate in the reaction, and their respective chemical reaction equations in molten iron are as follows: [0003] C (s) +FeO (l) =CO (g) +Fe (l) ……(1) [0004] 2Cr (s) +3FeO (l) =Cr 2 o 3(s) +3Fe (l) ……(2) [0005] Si (s) +2FeO (l) = SiO 2(s) +2Fe (l) ...(3) [0006] For the present stage of argon-oxygen refining of low-carbon ferrochromium alloys, in view of the chemical reaction between many elements and oxygen involved in the smelting process, and the total amount of oxygen input into the AOD furnace is limited, the elemen...

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Problems solved by technology

[0034] In order to solve the problem that the existing methods for refining low-carbon ferrochrome alloys with argon and oxygen fail to effectively simplify the gas component content model participating in the chemical reaction of each component element, and do not consider the surrounding and bottom surface of the AOD furnace at room temperature. The loss of heat loss makes the heat balance equation model inaccurate; the control of the removal rate of each element in the entire smelting process cannot be further improved, and the content of the gas components obtained by the solution is different from the actual smelting process. The deviation of the situation is large, resulting in a large error between the total oxygen consumption in the smelting process and the actual consumption through its solution; the existing method of cascading filters in the internal model controller in order to make the reciprocal of the control channel transfer function tend to converge , there are difficulties in the selection of its filter form, and it is impossible to make an effective evaluation of whether the determined filter time constant is optimal; and the existing methods fail to give precise control of the ratio of argon (nitrogen) / oxygen gas mixture As a result, the segmentation plan for dividing the rough smelting process into three stages of high-carbon smelting, medium-carbon smelting, and low-carbon smelting is not reasonable enough to effectively determine the oxygen supply in the corresponding process, resulting in blowout in the AOD furnace. The phenomenon of spattering or excessive waste of oxygen occurs from time to time, and the technical problem that the smelting time length, resource utilization rate and finished product qualification rate cannot be optimally controlled. The present invention provides an argon-oxygen refined ferrochrome carbon based on expert internal model control. content control method

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