SU711108A1 - Method of oxygen convertor process control - Google Patents

Description

one

The invention relates to metallurgy, namely, to the automation of an oxygen-converter process.

There is a known method of automatically controlling the purging process in the converter, based on the use of information about the initial and predetermined conditions of blowing, and to increase the yield of the casting, the gas pressure under the fireplace dome is measured, the flame temperature at the outlet of the converter neck and by processing this information the calculating unit determines the carbon burnout rate, temperature increase, iron burnout and the afterburning of CO and COg. In terms of the amount of FeO in the slag, the position of the tuyere is controlled, in terms of oxygen utilization, the flow rate is blown, and in terms of the rate of temperature rise and carbon burnout, the amount of their materials fed to the converter is cooled, and after the last addition the same function is performed by changing the distance tuyere nozzles from the calm metal level 1.

The disadvantage of the known method is the low accuracy of the process control due to the nonstationarity in the temporal relationship between the pressure of the gases under the dome of the fireplace and the rate of oxidation of carbon in the converter, which is caused, for example, by the nonstationarity in time

gut gi tract.

The closest to the invention in its technical essence and the achieved result is a method for controlling an oxygen converter process without post-combustion of flue gases, based on changing the position of the tuyere and oxygen consumption depending on the content of carbon dioxide in the flue gases and the consumption of combustion products, and the degree of utilization the oxygen entering the bath is determined by the thermal conductivity of the combustion products 2.

The disadvantage of this method lies in the low control accuracy associated with a large error in determining the consumption of combustion products.

Claims (1)

The purpose of the invention is to improve the accuracy. control of the smelting process in the converter. The goal is achieved by the fact that between changes in the position of the tuyere a time delay is equal to the response delay in the control objects for this change and determine the value of M (gas flow increment by changing the position of the tuyere) using the formula M where Q is the change in gas flow when changing tuyere position, m / s; D h is the change in the position of the tuyere, M, is raised with the tuyere, and when M O is lowered. The drawing shows schematically the technical equipment of the converter shop, the pressure control system and the control system according to the invention. The drawing shows converter 1, lance 2, movable damper 3 of the caisson, cooler 4 of converter gases, gas cleaning 5, blower 6, gate of 7 mounted in front of the blowers, pressure sensors 8, 9, compare unit 1Q, controller 11, actuator 12, zone 13 from burning gases under the flap; a flow meter 14 of waste gases, indicating device 15, extreme regulator 16, control input 17 of the extreme regulator, and 18 lances with an actuator. With the damper lowered (-2 minutes from the start of purging), the average pressure inside the damper is measured and compared with the pressure in the workshop. A signal proportional to the specified pressure difference is applied to the regulator acting on the gate drive. The regulator is set so that the average pressure under the flap exceeds the pressure measured outside the flap by about 1-2 mm of water. Art. At the same time, the zone 13 of burning the flue gases is set at a distance of 400 mm from the lower edge of the bed and is stabilized. The amount of supply air from the shop, in the combustion zone, is also stabilized, which determines the quasistationary content of CO in the exhaust gases. Thus, at the indicated CQi content in WASTE gases, it can be considered in the first approximation that the pressure control system "monitors the release of CO from the converter. This position allows the analysis of the dynamics of the process of carbon burnout in the bath of the converter to use only the flow of exhaust gases. By changing its value, one can estimate the change in the rate of oxidation of carbon in the bath of the converter. To decrease the duration of the purge, the rate of carbon oxidation is maintained at a maximum. The waste gas flow rate after slag is also maintained at the maximum level. The control of the purge process is as follows. At some point in time (after slag induction) a change in the position of the tuyere is made (e.g., lifting). At a time interval, the change in discharge gas flow rate is estimated. If the flow rate increases, the next change (schag) of the tuyere is made in the same direction. The change in gas flow rate is reevaluated. This sequence of actions is carried out until a change in the position of the tuyere causes an increase in the flow of exhaust gases. In the absence of a change in the gas flow rate, a change (step) in the position of the tuyere in the direction opposite to the original one and so on is made when the position of the tuyere changes or decreases as compared with the initial one. Thus, this method of changing the position of the tuyere allows the maximum value of the waste gas flow rate and, ultimately, the maximum carbon burnout rate in the converter bath to be maintained. In general, the proposed method can be characterized as a kind of extreme regulation of the converter process. The magnitude of the change in the position of the tuyere L h is chosen from the conditions for separating the response of the system (in this case, by changing the gas flow rate) against the background of interference (signal oscillations) to this change D h depends on the type of meter (inertia), characteristics of the control loop channels, and so on. For a 300-tonne converter, h 0.05-0.1 M. The magnitude DL is selected from the delay conditions in the control object, in the measuring channel and their inertia. For a 300-tonne converter t 2-5 s. The application of the proposed method allows: to simplify the assessment of the change in the rate of oxidation of carbon, since for its realization it is necessary to use a single flow meter, as compared with a CO, COi gas analyzer, waste gas flow meters and computing devices necessary to implement devices using known methods, as well as to increase the process is economical by operating at high carbon rates, which reduces the melting time. Claims The method of controlling an oxygen-converter process without post-combustion of exhaust gases, including measuring the flow of exhaust gases and changing the burn lance, characterized in that, in order to improve the accuracy of controlling the process of smelting in converters, between changes the position of the tuyere produces a time delay equal to the delay of the response in the control object to this change and determine the value M (the increment of the gas flow when the position of the tuyere is changed) by the formula M - ||, r4eAQ is the change in the gas flow rate when the position of the tuyere is changed, m / s;  h is the change in the position of the tuyere, M, with the tuyere raised, and with M O lowered. Sources of information taken into account in the examination 1. USSR author's certificate 263624, cl. C 21 C 5/30, 1970. 2 Copyright svidrte.t.stvo USSR 234433, CL. C 21 C 5/30, 1969.