JPS62156216A - Temperature controller for hot blast stove - Google Patents

Abstract

PURPOSE:To supply hot air under the most suitable condition required by a blast furnace, by obtaining amended set temp. of regenerative body by a computing element for setting regenerative body temp. and heating the regenerative body, if deviation is caused between hot air temp. and set temp. at finishing time of supplying hot air. CONSTITUTION:If a temp. (e) of regenerative body in a hot blast stove 7 matches a set temp. (d), on/off valves 11, 12 are opened and hot air is supplied. Hot air temp. is detected by a detector 18 and a temp. (f) at the time of completion of air supplying is inputted to a comparator 20. A set value (a) and the detected value (f) are compared at the comparator 20, if temp. deviation is found, the amended set value (d) of regenerative body temp. is calculated by a computing element 22 for setting regenerative body temp. and is outputted to a regenerative body temp. controller 9. The controller 9 burns burner based on the value (d) to carry out regeneration. In this way, hot air required by the blast furnace can be supplied under the most suitable condition and labor can be saved.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to a hot blast furnace temperature control device that can stably supply the temperature and air volume required by a blast furnace.

[Prior Art] In order to efficiently perform the reduction action in a blast furnace, hot air of a predetermined temperature and a predetermined air volume is required.

A hot blast furnace is used to supply hot air to the blast furnace.

As shown in Fig. 3, the hot air stove is equipped with a heat storage body 2 inside a furnace body 1, and with on-off valves 3a and 3b closed, on-off valves 3c and 3d are opened, and burner 4 burns the air. When the combustion air 5 and the fuel gas 5' are fed, the combustion gas passes through the heat storage body 2, heating the heat storage body 2 and storing heat, and when the heat storage body 2 reaches a predetermined temperature or higher, the on-off valve 3c, 3d
The burner 4 is opened to stop the combustion of the burner 4 and the supply of air 5 to stop heat storage, and the on-off valves 3a and 3b are opened to supply air 6, which is heated in the process of passing through the heat storage body 2, and the generated hot air is sent to the blast furnace. (not shown).

Usually, multiple hot blast furnaces are provided for one blast furnace facility, and when one is in a hot air supply state, the others are in a heat storage state, and the hot air is sent by alternately repeating the heat storage state and the hot air supply state. I have to.

[Problems to be solved by the invention] In the conventional hot air supply equipment described above, temperature management of the heat storage body,
The hot blast furnace that supplies hot air to the blast furnace is switched using a fixed timer and temperature alarm signal.

If the heat storage body is heated more than necessary, heat loss will be large, and if the switching is delayed and the hot air temperature decreases, a problem arises in that sufficient hot air temperature cannot be ensured.

In view of the above-mentioned circumstances, the present invention is intended to improve the accuracy of temperature control of a heat storage body and to make it possible to always stably supply the hot air required by the blast furnace.

[Means for Solving the Problems] The present invention includes a hot air temperature detector, a comparator that compares the output from the detector with a hot air set temperature at the end of supply and outputs a temperature deviation, and It is equipped with a heat storage body temperature setting calculator that calculates the set temperature of the heat storage body based on the deviation and blast furnace hot air requirements, and a heat storage body temperature controller that determines the heat storage body heating conditions so that the heat storage body set temperature is achieved. .

[Function] If there is a deviation between the hot air temperature at the end of hot air supply and the set temperature, the heat storage body temperature setting calculator calculates the corrected heat storage body setting humidity, and the heat storage body temperature controller adjusts the corrected heat storage body setting. The temperature is determined, the heating conditions for the next heat storage process are determined, and the heat storage body is heated.

[Example] The present invention will be described in detail below with reference to the drawings.

FIG. 1 is a system explanatory diagram of the present invention, in which 7 is a first hot-blast stove, 8 is a second hot-blast stove, 9 is a heat storage body temperature controller of the first hot-blast stove 7, and 10 is a second hot-blast stove 8. heat storage body temperature controller, 11,
Reference numerals 12, 13 and 14 indicate on-off valves provided in the ventilation passages 15 and 16, respectively, and 17 indicates the ventilation period.

Note that the combustion gas supply and discharge passages are omitted in the figure.

Temperature detectors 18.19 are provided near the exits of the hot stoves 7 and 8 in the ventilation passage 15.16, and the detection results from the temperature detector 18 are sent to the comparator 20, and the detection results from the temperature detector 19 are sent to the comparator 21. Enter. The outputs of the comparators 20 and 21 are respectively input to the heat storage body temperature set value calculators 22 and 23, and the respective calculation results are input to the heat storage body temperature controllers 9 and 10. Further, the temperature a at the end of blowing is set and input into the comparator 20.21, and the required blast furnace hot air temperature b and the required blast furnace air volume C@ are input into the heat storage body temperature set value calculator 22.23.

As shown in the above-mentioned closing, this device controls the temperature of the hot air stoves 2 and 2. Hot air stoves 7 and 8 alternately blow air and store heat, and the control device maintains the temperature of the heat storage body at the set value at the end of heat storage. It is something that I will try to do. When looking at one hot air stove, the hot air temperature is high at the start of air blowing due to sufficient heat storage (2), and as it approaches the end of air blowing, the hot air temperature decreases.

Therefore, in order to correct this and keep the hot air temperature constant throughout the blasting period, a cold air mixing control valve 32 is usually installed to automatically adjust the temperature of the hot air at the blast furnace inlet to maintain the set temperature. The heat storage body temperature setting value is changed in response to a change in the detection result from the temperature detector or a change in the hot air requirements of the blast furnace. Note that it goes without saying that the same method can be carried out even if there are three or more hot air stoves.

Further, since the temperature control for the first hot air stove 7 and the temperature control for the second hot air stove 8 are the same, the temperature control for the first hot air stove 7 will be explained below.

Hot air temperature setting value a at the end of blowing and blast furnace required hot air temperature b,
Based on the blast furnace required air @C, the heat storage body temperature setting calculator 22 calculates the heat storage body temperature that satisfies the above a, b, and c, and inputs the calculated result d to the heat storage body temperature controller 9.

The heat storage body temperature controller 9 determines the combustion conditions of the burner so that the calculation result d is obtained, and burns the burner to store heat.

When the detected temperature e of the heat storage body becomes equal to the set temperature d, combustion of the burner is stopped, and the on-off valves 11 and 12 are opened to supply hot air.

The temperature of the hot air is detected by a detector 18, and the temperature f at the end of blowing is input to the comparator 20.

The comparator 20 compares the set value a and the detected value f, and if there is a temperature deviation, the heat storage body temperature setting calculator 22 calculates a corrected heat storage body temperature setting value based on the deviation and controls the heat storage body temperature controller 9.
Output to. The heat storage body temperature controller 9 burns the burner based on this corrected heat storage body temperature setting value to store heat.

Thus, the optimal hot air required by the blast furnace can be supplied.

Even if the hot air requirements of the blast furnace change, by repeating the above operations, it is possible to match the requirements with the state of the hot air actually fed.

Although any temperature measuring device may be used for the heat storage body temperature controller 9, a non-contact type temperature detection device is preferable considering that the heat storage body undergoes thermal expansion and thermal contraction.

One example will be explained based on FIG. 2. Components in FIG. 2 that are the same as those shown in FIG. 3 are given the same reference numerals.

Temperature detectors and air flow rate detectors 26 and 27 are provided on the combustion air supply path 24 side and the hot air air supply path 25 side of the heat storage body 2, respectively.
In addition, a temperature detector/air volume detector 28 is provided in the hot air delivery path 34.

The detection result from the detector 26 is sent to the hot blast furnace outlet temperature calculator 29.
and the calculation results from the two calculation units and the detector 27
The detection results are input to the subtracter 30. A brick temperature is estimated in a heat storage body temperature calculator 31 based on the calculation result from the subtracter 30, and the estimation result is returned to the hot blast furnace outlet temperature calculator 29.

This temperature measuring device 32 mainly includes the detector 26.27.2B.
and hot blast furnace outlet temperature calculator 29, subtractor 30. It is constituted by a heat storage body temperature calculator 31.

In the heat storage process, the on-off valves 3a and 3b are closed, the burner 4 is ignited, and the combustion air 5 and fuel gas 5 are supplied from the combustion air supply path 24.
′ is sent. The combustion gas 33 passes through the heat storage body 2 and is discharged from the hot air supply path 25'.
In the process of passing through the heat storage body 2, heat exchange occurs between the two, and heat is stored in the heat storage body 2.

Next, when supplying hot air to the blast furnace, on-off valves 3c, 3
d is closed, the burner 4 is extinguished, and the on-off valves 3a and 3b are opened to supply air from the hot air air supply path 25.

The air is heated in the process of passing through the heat storage body 2 and becomes hot air, which is then sent to the blast furnace.

The basic formula for heat exchange between the combustion gas passing through the heat storage body and the heat storage body in the above heat storage process is as follows (1), (2), (1) where Ts: Heat storage body temperature Tf: Combustion gas temperature Th: Gas temperature at the inlet of the heat storage body Tc: Gas temperature at the outlet of the heat storage body TCE" Expected value of gas temperature at the exit of the heat storage body σS: Heat capacity of the heat storage body σf: Heat capacity of the combustion gas U: Gas flow rate λsf' Heat transfer between the heat storage body and the combustion gas rate.

Further, the above Th and Tc can be detected by the detectors 26 and 27, and the cap and U can be detected by the detectors 26 and 27. λ, f, σS, and σf are already known values obtained through experiments and calculations, and the unknowns in the above basic equation are the heat storage body temperature Ts, the combustion gas temperature Tr, and the expected outlet gas temperature TCE. be.

From equation (1), the difference TE between the expected temperature and the actual temperature is determined from equation (4) using equation (1°), equation (1"°), and equation (2'), which is the detected gas outlet temperature Tc. It will be done.

T E = T C E T c
...(4) If this temperature difference T is found, the temperature difference T
The heat storage body temperature T, which is the basis for determining E. If the value Ts is corrected, a value Ts closer to the actual temperature of the heat storage body can be obtained.

This is expressed by the following formula (5).

TS = G-T Miju Tso...(
5) Here, G is a correction gain for determining the corrected offset temperature when a temperature difference TE occurs.

The predicted value T is calculated again based on the corrected temperature obtained using equation (5). Find E and compare it with Tc. The series of calculations described above is performed until TCE and Tc match, and Ts used when TCE and Tc match is the actual heat storage body temperature.

Also, the initial T, used to start the first calculation. may be input by the operator as appropriate based on his or her experience.

The hot blast furnace outlet temperature calculator 29 calculates the equation (3), the subtractor 30 calculates the equation (4), and the heat storage body temperature calculator 31 calculates the equation (5).
. Repeat until E and Tc match.

Note that the above calculation may be performed continuously or at predetermined intervals.

Effects of the Invention] As described above, according to the present invention, hot air can be supplied under optimal conditions required by the blast furnace, and labor can be saved.

[Brief explanation of drawings]

FIG. 1 is an explanatory diagram of the system of the present invention, FIG. 2 is an explanatory diagram of a temperature measuring device for a heat storage body used in the present invention, and FIG. 3 is an explanatory diagram of a hot air stove. 9.10 is a heat storage body temperature controller, 18.19 is a temperature detector, 20.21 is a comparator, and 22.23 is a heat storage body temperature calculator.

Claims (1)

[Claims] 1) A hot air temperature detector, a comparator that compares the output from the detector with the hot air set temperature at the end of feeding and outputs a temperature deviation, and a A hot-air stove temperature control device comprising: a heat storage body temperature setting calculator that calculates a set temperature; and a heat storage body temperature controller that determines heat storage body heating conditions so as to achieve the heat storage body set temperature.