JPS5935403B2 - Hot air supply method - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention sequentially switches and operates three or more hot air stoves between a combustion state for storing heat and a hot air supply state, and operates the plurality of hot air stoves in a state other than the time of switching between a combustion state for heat storage and a hot air supply state. supply state and other hot air stoves to the combustion state, and during the switching from the combustion state to the hot air supply state and from the hot air supply state to the combustion state, set both front wind stoves to be switched to the hot air supply state. The present invention relates to a hot air supply method in which communication is temporarily established by operating at least one of a discharge pressure valve and a pressure filling valve.

In the hot air supply method described above, in order to supply the residual pressure of the hot air stove that is to be transferred from the hot air supply state to the combustion state to the hot air stove that is to be transferred to the hot air supply state next, conventionally, for example, the valve operation shown in FIG. As shown in the time chart, the combustion-related valves of the first hot air stove H0 in the combustion state, that is, the fuel supply main valve 1, the cutoff valve 2, the combustion air cutoff valve 3, and the flue valve 5, are , the blow-related valves of the third hot-blast furnace H3 in the hot air supply state, that is, the blow-off valve 7 and the hot-air valve 9, are simultaneously started to close in that order by inputting the furnace switching signal a, and the last combustion-related valve is The exhaust pressure valve 4 of the first hot air stove H1 is closed by the fully closing completion signal of the flue valve 5.
At the same time as the exhaust pressure valve 4 is fully opened, the exhaust pressure valve 4 of the third hot air stove H3 is opened and the two front blast furnaces H1 and H3 are temporarily communicated with each other. valves 1, 2, which are operated to close the first hot air stove H1 to be stopped;
3.5, the air blowing of the third hot air stove H3 is stopped first, and the pressure of both furnaces H1 and H3 is equalized further after the combustion of the first hot air stove H0 is stopped, so the air blowing is stopped. Until the pressure is equalized, the internal pressure of the third hot air stove H3 becomes almost the same as the internal pressure of the hot air supply main pipe 21, and the third hot air stove H3
Until the internal pressure of the third hot air stove H3 is reduced by pressure equalization, the hot air valve 9 of the third hot air stove H3 will rattle due to the pulsating flow phenomenon of the hot air flowing through the hot air supply flow path, and there is a great risk of damaging the hot air valve 9. Met.

Moreover, after the third hot air furnace H3 stops supplying hot air, the first
Since it takes a long time for the hot air stove H1 to start supplying hot air, it would be difficult to have the other hot air furnace independently supply the hot air during that time.
There is a disadvantage that the pressure drop of the hot air passing through the furnace is small, the operating efficiency decreases during that time, and the load on the hot air supply blower increases.Furthermore, the number of valves of the first hot air furnace H1 that must stop combustion is Due to the large number of blowers and the tendency to cause thermal troubles, once a trouble occurs, the time for individual air blowing becomes even longer, resulting in a noticeable decrease in operational efficiency and a continued increase in blower load. .

Of course, a similar problem occurs when switching between different combinations of furnaces.

In view of the above-mentioned circumstances, it is an object of the present invention to make it possible to eliminate the above-mentioned drawbacks with extremely simple improvements.

Next, a hot air supply device used in the method of the present invention will be explained based on illustrative drawings.

A combustion chamber 14 formed by connecting a fuel gas supply pipe 11 and a combustion air supply pipe 12 to a combustion device 13, and the combustion chamber 14
The heat storage chamber 15 connected to the four hot air stoves H11H21
The flue main pipe 16 and the pressure equalization pipe 23 are connected in parallel to the chimney 24, and each of the hot blast furnaces H1 to H4 has a flue pipe 17, 17 communicating with the flue main pipe 16 and the pressure equalization pipe Pressure equalization/exhaust pipe 25 communicating with pressure pipe 23, air blower 1
A blast pipe 20 is connected to a main air pipe 19 from 8, and a hot air pipe 22 is connected to a main pipe 21 for supplying hot air to a hot air supply target 26 such as a blast furnace.

The fuel gas supply pipe 11 is provided with a main valve 1 and a cutoff valve 2, the air supply pipe 12 is provided with a cutoff valve 3, and the pressure equalization/exhaust pipe 2 is provided with a cutoff valve 3.
5 is provided with a small diameter exhaust pressure valve 4, and a flue pipe 17° 1T is provided with a large diameter flue valve 5, respectively, and a small diameter filling valve 6 and a large diameter blower are connected in parallel to the blower pipe 20. A blow distribution control valve 8 is provided with the valve 7 located upstream of the blow valve 7, and a hot air valve 9 is provided in the hot air pipe 22, and a main valve 10 is provided in the lowest downstream of the pressure equalizing pipe 23, respectively. At the same time, each of the valves is controlled in accordance with the time chart shown in Fig. 2, so that the hot air supply states of the leading furnace and the trailing furnace are overlapped in half, and the four hot blast furnaces H1, H2, H3
, H4 are sequentially switched between a combustion state for heat storage and a hot air supply state to constitute a hot air supply device.

When setting the valve operation pattern in the time chart shown in FIG.
1 and H2 are in the combustion state, and the third hot air stove H3 is leading and the third and fourth hot air stoves H3 and H4 are in the hot air supply state, the first hot air stove H1 is in the hot air supply state and When switching the third hot air stove H3 to the combustion state, first, in a state where the furnace switching signal a is transmitted, the gas main valve 1, the gas cutoff valve 2, the air cutoff valve 3, which are related to heat combustion of the hot air stove H1,
The flue valves 5 are started to be closed in that order, and at or immediately after the combustion stop of the hot air stove H1 is started,
The furnace switching signal a is inputted to start the opening operation of the exhaust pressure valve 4 of the hot blast stove H1, and finally, by the signal indicating the completion of fully closing the flue valve 5, the hot blast of the third hot blast stove H8 is changed. The supply-related blower valve 7 and the hot air valve 9 are started to be closed in that order, and the hot air valve 9 is closed in response to the signal C indicating the completion of full closing of the hot air valve 9 that is closed last to stop the hot air supply.
Simultaneously or almost simultaneously with the full closing of the third hot-blast stove H3, the exhaust pressure valve 4 of the third hot-blast stove H3 is opened to temporarily bring the two furnaces H1, H into communication with each other to equalize the pressure.

Then, by a signal d indicating completion of closing of the exhaust pressure valve 4 of the first hot-blast stove H1 after a predetermined time has elapsed, that is, a signal d indicating the start of hot-blast supply from the first hot-blast stove H1 and the start of combustion from the third hot-blast stove H3. , the exhaust pressure source valve 10 and the pressure charging valve 6 of the first hot air stove H1 are temporarily opened and closed, and while the exhaust pressure source valve 10 is opened, the third
The flue valves 5, 5, air cutoff valve 3, gas cutoff valve 2, and gas source valve 1 of the hot air stove H3 are started to be opened in that order, and the exhaust pressure valve 4 is closed by fully opening the flue valves 5, 5. The operation is started to start combustion in the third hot air stove H3, and the first
When the charging valve 6 of the hot air stove H1 is opened, the blower valve 7 and the hot air valve 9 thereof are opened in that order to start supplying hot air from the first hot air stove H1.

In addition, by the fully closing completion signal of the flue valve 5, the blow valve 7 and the hot air valve 9 of the third hot air stove H3 may be started to close simultaneously, or the hot air valve 9 and the blow valve 7 may be closed simultaneously. The valve operation pattern described above is for switching the first hot air stove H1 from the combustion state to the hot air supply state and the third hot air stove H3 from the hot air supply state to the combustion state. However, switching between other combinations of different furnaces is performed in the same manner.

FIG. 3 shows a first modified configuration of the hot air supply device, in which the pressure equalizing pipe 23 for the chimney 24 is
is omitted, and the exhaust pressure pipe 25 connected to the pressure equalization pipe 23 is omitted.
is connected to the flue main pipe 16, and a pressure equalizing pipe 28 is connected in parallel to the blower 18 via the main valve 27, and the pipe equipped with the pressure filling valve 6 is used as a pressure equalizing and filling pipe 29, and these are connected. It is connected to the pressure equalizing pipe 28, and according to the valve operation pattern shown in the time chart shown in FIG. 4, the charging valve 6 of the third hot blast furnace H3 in the hot air supply state starts opening operation in response to the furnace switching signal a. At the same time, the gas source valve 1, gas cutoff valve 2, air cutoff valve 3, and flue valve 5 of the first hot air stove H1 in the combustion state start closing operations in that order, and the flue valve 5 is finally closed. The blow valve 7 and the hot air valve 9 of the third hot air stove H3 have already started the closing operation in that order, and at the fully closed signal C of the hot air valve 9 that is closed last, the first hot air stove H1 is closed. The pressure in both furnaces H, , H3 is equalized between the time when the pressure charging valve 6 of the third hot blast furnace H3 starts to open and the pressure filling valve 6 of the third hot blast furnace H3 closes.

Then, in response to the closing signal d of the pressure charging valve 6 that has completed the pressure equalization, the pressure source valve 27 is temporarily opened and closed, and the first hot air stove H0 is brought into the hot air supply state and the third hot air stove H3 is brought into the combustion state. I'm trying to move it.

FIG. 5 shows a second modified configuration of the hot air supply device, in which a pressure equalizing pipe 28 is connected in parallel to the blower 18 via the main valve 27, and a pipe provided with the pressure filling valve 6 is connected in parallel to the blower 18 via the main valve 27. is connected to the pressure equalizing pipe 28 as a pressure equalizing and charging pipe 29, and according to the valve operation pattern shown in the time chart shown in FIG. 6, the first hot air stove H1 in the combustion state is The exhaust pressure valve 4 and the charging valve 6 of the third hot air stove H8 in the hot air supply state start opening operations, respectively, and at the same time, the gas source valve 1, the gas cutoff valve 2, and the air cutoff valve 3 of the first hot air stove H1 in the combustion state , the flue valves 5 start the closing operation in that order, and the final closing signal of the flue valve 5 is fully closed. The blow valve 7 and the hot air valve 9 of the third hot air stove H3 have already started the closing operation in that order. The charging valve 6 of the first hot air stove H1 is activated by the fully closing signal C of the hot air valve 9 which starts and finally closes.
The charging and exhaust pressures are maintained until the exhaust pressure valves 4 of the third hot-air stove H2 each start to open and the exhaust pressure valves 4 of the first hot-air stove H1 and the charging valves 6 of the third hot-air stove H3 close, respectively. Both furnaces H1 and H3 are pressure-equalized at the same time using two paths, which reduces the load on the charging and exhausting pressure valves 4, 4, and 6.6, and shortens the pressure equalization time. .

Then, in response to the signal d indicating the completion of closing of the exhaust pressure valve 4 of the first hot-air stove H1 and the filling valve 6 of the third hot-air stove H3, the exhaust pressure source valve 10 and the light pressure source valve 27 are temporarily opened and closed. 1 hot stove H
1 to the hot air supply state and the third hot air stove H3 to the combustion state.

In summary, in the hot air supply method described above, the present invention provides that, in the switching, the combustion state should be switched from the combustion state to the hot air supply state at the time when the heating stop of the hot air furnace H1 to be switched from the combustion state to the hot air supply state is started or immediately thereafter. The opening operation of at least one of the exhaust pressure valve 4 of the hot air stove H1 or the pressure filling valve 6 of the hot air stove H3 to be switched from the hot air supply state to the combustion state is started, and at the same time, the opening operation of at least one of the exhaust pressure valve 4 of the hot air stove H1 to be switched from the combustion state to the hot air supply state is started. Valve 1 for stopping combustion;
2, 3.5 are all closed, the valves 7 and 9 for stopping the hot air supply of the hot air stove H3 to be switched from the hot air supply state to the combustion state are closed, and both the valves 7 and 9 are closed. At the same time or almost at the same time that both become fully closed, 1
It is characterized by starting the opening operation of at least one of the exhaust pressure valve 4 of the hot air stove H3 to be switched from the hot air supply state to the combustion state, or the charging valve 6 of the hot air stove H1 to be switched from the combustion state to the hot air supply state.

That is, after the combustion of the hot air stove H1, which should be switched from the combustion state to the hot air supply state, is completed, the hot air supply of the hot air stove H3, which is to be switched from the hot air supply state to the combustion state, is stopped, and after the completion of the hot air supply, the hot air supply is stopped. This is to start the pressure operation, and by equalizing the pressure at the same time as the hot air valve 9 and the blower valve 7 are closed, the internal pressure of the hot air stove H3, which has completed hot air supply, becomes the same as that of the hot air supply main pipe 21. The pressure does not become the same as the internal pressure, thereby avoiding damage to the hot air valve 9 due to vibration, and greatly extending the service life of the hot air valve 9.

Moreover, since the independent supply of hot air at the time of switching is limited to only during pressure equalization operation, the time for independent air supply can be greatly shortened compared to the conventional method. In addition to reducing the load on the charge/discharge pressure valve, shortening the pressure equalization time can further shorten the individual air blowing time, improving operational efficiency and reducing the load on the blower 18. Even if a problem occurs with a valve that should be stopped, it is no longer necessary to continue reducing operating efficiency or increasing the blower load, as was the case in the past.

At the time of pressure equalization, the valve opening control of at least one of the exhaust pressure valve 4 of the hot air stove H0 to be switched from the combustion state to the hot air supply state, or the charging valve 6 of the hot air stove H5 to be switched from the hot air supply state to the combustion state, is performed. Since this is done according to the timing of furnace switching, it is easy to modify the control system, and as a whole, it is possible to eliminate the drawbacks of the conventional method by simply changing and setting the pressure equalization operation timing. Became.

BRIEF DESCRIPTION OF THE DRAWINGS The drawings illustrate an embodiment of the hot air supply device used in the method of the present invention, FIG. 1 is a schematic system diagram, and FIG. 2 is a valve operation time chart thereof. 3 and 5 are schematic system diagrams of the hot air supply devices of the first and second modified configurations, respectively, and FIGS. 4 and 6 are valve operation time charts thereof. FIG. 7 is a valve operation time chart of a conventional hot air supply device. 1.2, 3.5... Combustion stop valve, 4...
...Exhaust pressure valve, 6...Pressure valve, 7,9...
・Hot air supply stop valve, H7~H4・River...Hot blast stove.

Claims (1)

[Claims] The 13 or more hot air stoves H1 to H4 are sequentially switched and operated between the combustion state for heat storage and the hot air supply state, and the plurality of hot air stoves H3 and H4 are switched to the hot air supply state and other When the hot air stoves H1 and H2 are in the combustion state, and during the switching from the combustion state to the hot air supply state and from the hot air supply state to the combustion state, both the front wind stoves H1 and H3 to be switched and both front wind stoves are switched. A hot air supply method in which communication is made temporarily by operating at least one of the exhaust pressure valve 4 or the pressure filling valve 6 of H1 and H3, and in the switching, the combustion stop of the hot air stove H1 to be switched from the combustion state to the hot air supply state is started. At or immediately after
The opening operation of at least one of the exhaust pressure valve 4 of the hot air stove H1 to be switched from the combustion state to the hot air supply state or the charging valve 6 of the hot air stove H3 to be switched from the hot air supply state to the combustion state is started, and the hot air is switched from the combustion state to the combustion state. Combustion stop valves 1, 2, 3, of hot air stove H1 to be switched to supply state;
5 are all closed, the valves 7 and 9 for stopping the hot air supply of the hot air stove H8, which is to be switched from the hot air supply state to the combustion state, are closed, and both of the valves 7 and 9 are fully closed. An exhaust pressure valve 4 of a hot air stove H3 to be switched from a hot air supply state to a combustion state at the same time as or almost simultaneously with the closed state;
Alternatively, the hot air supply method is characterized by starting an opening operation of at least one of the charging valves 6 of the hot air stove H1 to be switched from the combustion state to the hot air supply state.