RU2553147C2 - System of automatic control of metal heating in heating furnaces of discontinuous operation - Google Patents

Abstract

FIELD: metallurgy.

SUBSTANCE: invention relates to the metallurgy and can be used for automatic control of the thermal mode of the heating furnaces with discontinuous operation. System of automatic control of the metal heating in the heating furnaces of discontinuous operation containing block of task generation for metal thermal absorption, block determining the metal thermal absorption comprising heat meter and differentiator, three comparing units, air flow regulator, block of task generation for lining temperature change rate, block determining the lining temperature change rate, fuel flow regulator; first inputs of the first and second comparing units are connected with output of the block determining the metal thermal absorption, and second outputs are connected to output of the block of task generation for metal thermal absorption, output of the second comparing unit is connected with air flow regulator, output of the first comparing unit is connected to the block of task generation for lining temperature change rate, its output is connected with the first input of the third comparing unit, its second input is connected to the block determining the lining temperature change rate, and output of the third comparing unit is connected with fuel flow regulator, additionally block determining rate of scale thickness rise, block for setting as per scale minimum, forth comparing unit are included, at that output of the block determining the metal thermal absorption is connected with input of the block determining rate of scale thickness rise, its output is connected to the first input of the forth comparing unit, its second input is connected with the block for setting as per scale minimum, and output of the forth comparing unit is connected with air flow regulator.

EFFECT: improved quality of regulation of the furnace thermal modem and reduced fuel consumption for metal heating, improved quality of billets heating.

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Description

The invention relates to metallurgy and can be used to automatically control the thermal regime of batch heating furnaces.

The well-known "System of automatic temperature control in the furnace" (USSR Author's Certificate No. 1183812, F27D 19/00, 1985), comprising a temperature sensor installed in the temperature control zone, temperature controllers and fuel-to-air flow ratios, and fuel supply actuators and air.

The disadvantage of this system is the lack of current information about the actual heating of the metal, that is, about the heat flux absorbed by the metal, which leads to an excessive consumption of fuel.

The well-known "System of automatic regulation of indirect radiation regime of a batch heating furnace" (Patent for the invention of the Russian Federation No. 2030462, IPC C21D 11/00, F27D 19/00, 1995), adopted as a prototype, containing a master and an adjustable parameter sensor, two blocks comparison, the first inputs of which are connected to the output of the adjustable parameter sensor, the second inputs are connected to the output of the setter, and the output of the second comparison unit is connected to the air flow regulator, contains heat absorption of metal, and as a sensor of an adjustable parameter - a unit for determining heat absorption of metal, the system is equipped with a unit for generating a task for the rate of change of the lining temperature, a third comparison unit, a unit for determining the rate of change of the temperature of the lining, a fuel consumption regulator, the input of which is connected to the output of the third unit comparison, the inputs of which are connected to the output of the unit for forming the task according to the rate of change of the temperature of the lining and with the output of the unit for determining the measurement speed neniya lining temperature; while as a unit for determining the heat absorption of metal, the system comprises a device for measuring the heat flux absorbed by the metal, set at the level of the heated metal, the output of which is connected to the differentiator; as a unit for determining the rate of change of the temperature of the lining, the system contains a thermocouple installed in the arch of the furnace at the level of the inner surface of the lining, the output of which is connected to the differentiator.

The disadvantage of this system is the lack of assessment of the thermophysical state of the metal in the batch furnace in real time, namely, current information about the actual thickness of the scale.

The technical result of the claimed invention is to improve the quality of the process of regulating the thermal regime of the furnace and, as a result, reduce fuel consumption for heating the metal and improve the quality of heating the workpieces.

The technical result is achieved in that a system for automatically controlling the heating of metal in batch heating furnaces, comprising a unit for generating a metal heat absorption task, a metal heat absorption determination unit, consisting of a heat meter and a differentiator, three comparison units, an air flow regulator, a task formation unit for the rate of change lining temperature, block for determining the rate of change of lining temperature, fuel consumption regulator; the first inputs of the first and second comparison units are connected to the output of the metal heat absorption determination unit, and the second outputs are connected to the output of the metal heat absorption task formation unit, the output of the second comparison unit is connected to the air flow regulator, the output of the first comparison unit is connected to the task formation unit by the rate of change temperature of the lining, the output of which is connected to the first input of the third comparison unit, the second input of which is connected to the unit for determining the rate of change of temperature fu calibration, and the output of the third comparison unit is connected to the fuel consumption regulator, further comprises a block for determining the growth rate of scale, a task for minimizing scale, and a fourth comparison unit, while the output of the unit for determining heat absorption is connected to the input of the unit for determining the rate of increase in scale thickness, the output of which connected to the first input of the fourth comparison unit, the second input of which is connected to the output of the reference unit for minimum scale, and the output of the fourth comparison unit is connected to the flow controller air.

Figure 1 and figure 2 presents a block diagram of a system for automatically controlling the heating of metal in batch heating furnaces.

The system for automatically controlling the heating of metal in batch heating furnaces includes: a heat absorption determination unit 1, a metal heat absorption task generation unit 2, a first comparison unit 3, a second comparison unit 4, an air flow regulator 5, a task formation unit according to the rate of change of the lining temperature 6, third comparison unit 7, a unit for determining a rate of change of temperature of the lining 8, a fuel consumption regulator 9; a unit for determining the growth rate of the thickness of the scale 10, a task unit for minimizing the scale 11, and a fourth comparison unit 12.

A system for automatically controlling the heating of metal in batch heating furnaces comprises: a heat absorption determination unit 1, consisting of a heat meter and a differentiator, the input of which is connected to the output of the heat meter, and the output is the output of the metal heat absorption determination unit; a unit for forming a task for heat absorption of metal 2; the first comparison unit 3 and the second comparison unit 4, the first inputs of which are connected to the output of the metal heat absorption determination unit 1, and the second to the output of the metal heat absorption task formation unit 2, the output of the second comparison unit 4 is connected to the air flow regulator 5; the output of the first comparison unit 3 is connected to the task forming unit according to the rate of change of the temperature of the lining 6, which is connected to the third comparison unit 7, connected to the unit for determining the rate of change of the temperature of the lining 8 and the fuel consumption regulator 9; the unit for determining the rate of change of temperature of the lining 8 consists of a thermocouple installed in the arch of the furnace at the level of the inner surface of the lining, and a differentiator, the input of which is connected to the output of the thermocouple, and the output is the output of the unit for determining the rate of change of temperature of the lining 8; the output of the heat meter of the heat absorption determination unit 1 is connected to the input of the scale thickness growth rate determining unit 10, the output of which is the first input of the fourth comparison unit 12, the second input for which is the output from the minimum scale descaling unit 11, the output of the fourth comparison unit 12 is connected to the flow regulator air 5.

The system operates as follows.

The following information is entered into the unit for forming a task for heat absorption of metal 2:

- steel grade of the heated metal, geometric dimensions of the workpieces, thermophysical parameters of the metal;

- the duration of heating the metal;

- metal temperature at the beginning and end of heating;

- lining temperature at the beginning of heating.

, который поступает на вход регулятора расхода воздуха 5, который формирует управляющее воздействие на расход воздуха (основной канал). Сигналы от блоков определения скорости роста толщины окалины 10 и формирования задания по минимуму окалины поступают на четвертый блок сравнения 12, который формирует сигнал рассогласования текущего и заданного значений скорости роста окалины $${\epsilon }_3={\left(\frac{\delta H}{\delta \tau }ок\right)}^{изм}-{\left(\frac{\delta H}{\delta \tau }ок\right)}^{зад}$$

, в зависимости от которого регулятор расхода воздуха 5 формирует управляющее воздействие на расход воздуха (канал компенсации). Сигнал по измеренному теплопоглощению от блока определения теплопоглощения 1 поступает на первый блок сравнения 3, сюда же поступает сигнал по заданному теплопоглощению от блока формирования задания по теплопоглощению 2; полученный на первом блоке сравнения 3 сигнал ошибки $${\epsilon }_1=q_{м}^{зад}(\tau )-q_{м}^{изм}(\tau )$$

поступает на вход блока формирования задания по скорости изменения температуры футеровки 6, который по разности теплопоглощения, заданного программой и измеряемого блоком определения теплопоглощения 1, формирует сигнал текущего задания по скорости изменения температуры футеровки $${\left(\frac{\delta T}{\delta \tau }фут\right)}^{зад}=f({\epsilon }_1)$$

, который поступает на третий блок сравнения 7. Сюда же поступает сигнал по измеренной скорости изменения температуры футеровки от блока определения скорости изменения температуры футеровки 8. Регулятор расхода топлива 9 формирует управляющее воздействие на расход топлива в зависимости от разности измеренной и заданной скорости изменения температуры футеровки $${\epsilon }_2={\left(\frac{\delta T}{\delta \tau }фут\right)}^{изм}-{\left(\frac{\delta Т}{\delta \tau }фут\right)}^{зад}$$

.Based on these data, the heat absorption task generation unit 2 calculates the metal heat absorption, which is a program task for a system for automatically controlling metal heating in batch heating furnaces. On the basis of the same data, the unit for forming a task for minimum scale 11 generates a task for the thickness of the scale. These signals are used by fuel and air regulators to form control actions on control valves. The unit for determining the growth rate of the scale thickness 10 using the differentiation operation determines the rate of increase in the thickness of the scale based on the data received from the heat absorption unit 1. The signals from the heat absorption task generation unit 2 and the heat absorption unit 1 are sent to the second comparison unit 4, which generates a signal mistakes $${\epsilon }_{\mathrm{one}}=q_m^{s\mathrm{but}d}(\tau )-q_m^{\mathrm{and}sm}(\tau )$$

, which enters the input of the air flow regulator 5, which forms a control action on the air flow (main channel). The signals from the blocks for determining the growth rate of the scale thickness 10 and the formation of the task for the minimum of scale are sent to the fourth comparison unit 12, which generates a signal of a mismatch between the current and the specified values of the scale growth rate $${\epsilon }_{}$$$${}_3={\left(\frac{\delta H}{\delta \tau }\mathrm{about}\mathrm{to}\right)}^{\mathrm{and}sm}-{\left(\frac{\delta H}{\delta \tau }\mathrm{about}\mathrm{to}\right)}^{s\mathrm{but}d}$$

, depending on which the air flow regulator 5 generates a control effect on the air flow (compensation channel). The signal according to the measured heat absorption from the heat absorption determination unit 1 is supplied to the first comparison unit 3, the signal according to the given heat absorption from the formation unit of the heat absorption task 2 is also received here; error signal received on the first comparison unit 3 $${\epsilon }_{\mathrm{one}}=q_m^{s\mathrm{but}d}(\tau )-q_m^{\mathrm{and}sm}(\tau )$$

enters the input of the task formation unit according to the rate of change of the temperature of the lining 6, which, by the difference in heat absorption specified by the program and measured by the heat absorption determination unit 1, generates a signal of the current task according to the rate of change of the temperature of the lining $${\left(\frac{\delta T}{\delta \tau }f\mathrm{at}t\right)}^{s\mathrm{but}d}=f({\epsilon }_{\mathrm{one}})$$

, which enters the third block of comparison 7. This also receives a signal for the measured rate of change of the temperature of the lining from the unit for determining the rate of change of the temperature of the lining 8. The fuel flow regulator 9 generates a control effect on fuel consumption depending on the difference between the measured and the specified rate of change of the temperature of the lining $${\epsilon }_{}$$$${}_2={\left(\frac{\delta T}{\delta \tau }f\mathrm{at}t\right)}^{\mathrm{and}sm}-{\left(\frac{\delta T}{\delta \tau }f\mathrm{at}t\right)}^{s\mathrm{but}d}$$

.

Using this system to control metal heating in batch furnaces allows heating to a minimum of scale thickness, forming a control effect on air consumption by the rate of increase of metal scale thickness, which improves the quality of regulation of the thermal regime of the furnace and, therefore, saves fuel and optimizes the heating process blanks, as well as improve the quality of their heating.

Claims (1)

A system for automatically controlling the heating of metal in batch heating furnaces, comprising a unit for generating a metal heat absorption task, a metal heat absorption determination unit consisting of a heat meter and a differentiator, three comparison units, an air flow regulator, a task formation unit for the speed of the lining temperature changing, a determination unit the rate of change of the temperature of the lining, the fuel consumption regulator, while the first inputs of the first and second comparison units are connected to the output m of the metal heat absorption determination unit, and the second inputs are connected to the output of the metal heat absorption task formation unit, the output of the second comparison unit is connected to the air flow regulator, the output of the first comparison unit is connected to the task formation unit according to the speed of the lining temperature change, the output of which is connected to the first input the third comparison unit, the second input of which is connected to the unit for determining the rate of change of the temperature of the lining, and the output of the third comparison unit is connected to the regulator fuel flow, characterized in that it is equipped with a unit for determining the growth rate of the scale of the metal, a unit for setting the minimum thickness of the metal scale and the fourth unit of comparison, while the output of the unit for determining heat absorption is connected to the input of the unit for determining the growth rate of thickness of the metal scale, the output of which is connected to the first input of the fourth comparison unit, the second input of which is connected to the output of the task unit to minimize the thickness of the metal scale, and the output of the fourth comparison unit is connected to the flow controller but air.

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