JPS6326165B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a staggered parallel air blowing operation system for a hot air stove.

A hot blast furnace is one of the auxiliary equipment of a blast furnace in a steelworks. A hot blast furnace is a heat storage type exchanger that heats the air blown to the blast furnace to make it high temperature, and is composed of a heat storage chamber that gives heat to the air blown, and a combustion chamber that heats this heat storage chamber. ing. First, during the heat storage period, the gas valve, air valve, and flue valve of the hot stove are opened, and fuel gas such as blast furnace gas is taken in from the gas valve, and combustion air is taken in from the air valve and burned in the combustion chamber, thereby storing heat. Heat the room sufficiently. The combustion exhaust gas is discharged from the flue valve. When the heating of the regenerator is completed, the gas valve, air valve and flue valve close to end the combustion state. Next, open the blower butterfly valve, blower valve, and hot air valve of the hot air stove. Then, the blast air is heated by passing through the heat storage chamber of the hot blast furnace via the butterfly valve and the blast valve, and is sent to the blast furnace as hot air from the hot blast valve. Note that the butterfly valve is a valve for adjusting the amount of air being blown. Therefore, one hot blast furnace has a heat storage period in which it is in a combustion state and is heated, a blowing period in which hot air is blown to the blast furnace, and a rest period in which it is not in either of these periods. Four or more hot-blast stoves are arranged for one blast furnace, and two of the hot-blast stoves are in a blowing state and the other hot-blast stoves are in a combustion state or in a dormant state. The two hot blast furnaces that are in the blowing state have a leading furnace that goes into the blowing state first and a trailing furnace that goes into the blowing state later.The leading furnace is faster than the trailing furnace. Since we started blowing hot air, the amount of retained heat is decreasing. The hot air from both hot blast furnaces is mixed and sent to the blast furnace. Therefore, the temperature of the hot air sent to the blast furnace can be controlled by adjusting the opening degree of each blow butterfly valve of the two hot blast furnaces in the blowing state and changing the distribution ratio of the air volume passing through both furnaces. can. In other words, if a large amount of air is passed through the leading furnace, which has already reduced its heat capacity, and a small amount of air is passed through the trailing furnace, which still has a large amount of heat, the overall temperature of the hot air will decrease, and vice versa, the temperature will rise. do. In this way, the two hot blast furnaces blow air into the blast furnace, and when the heat capacity of the preceding furnace decreases and reaches its limit, the preceding furnace is shifted from the blowing state to the idle state, and the second hot blast furnace, which has been in a heat storage state, The third hot air stove is shifted to the blowing state, that is, the furnace is replaced, and the two hot air stoves continue blowing air. The operating method of such a hot air stove is called the Statsgard parallel blower operating method, and is widely used today.

Now, in such a conventional staggered parallel air blowing operation system, all of the hot blast furnaces consisting of at least four units operate automatically in response to commands from an operation schedule control device. That is, when an air blowing command issued by the operation schedule control device according to a predetermined schedule is detected, the air blowing butterfly valve of the hot air stove that is in the air blowing state is selected and operated to perform air blowing control. Since there is a constraint that four hot-blast stoves must be operated automatically, all other hot-blast stoves other than the two hot-blast stoves that are blowing air in parallel will also operate automatically, regardless of whether they are in the combustion state or in the idle state. automatic operation must continue. In other words, since parallel air blowing operation is performed by two hot air furnaces that are in the air blowing state, the other two hot air furnaces are either in the combustion state or in the dormant state, and are not directly related to the parallel air blowing. Therefore, even if you want to perform semi-automatic or manual operation on only these hot air stoves, you must stop the parallel air blowing operation of the hot air stove itself and switch to single air blowing. It didn't happen. Additionally, if a malfunction has occurred in another hot-blast stove that is in the combustion or dormant state other than the two hot-air stoves that are in parallel fan operation, and you want to remove it from automatic operation and repair it, you must stop parallel fan operation. This caused the inconvenience of having to switch to single fan operation.
That is, in order to maintain the parallel air blowing operation, there was a troublesome restriction that all four hot air stoves, including the other hot air stoves that were not in the air blowing state, had to enter automatic operation without fail.

This invention was made in order to eliminate the above-mentioned troublesome restrictive conditions in the staggered parallel blowing operation of hot air stoves. When a hot air stove is performing parallel air blowing in automatic operation, other hot air stoves that are not in the air blowing state are temporarily removed from the restrictions of automatic operation and can take on an arbitrary and appropriate operation mode, but for that purpose, the stand guard parallel air blower is The object of the present invention is to provide an automatic operation method for a hot air stove that allows continuous operation without stopping the operation itself.

The main point of the configuration of this invention is that in an operation system in which a plurality of four or more hot air stoves are automatically operated under instructions from an operation schedule control device to perform staggered parallel air blowing, Only when changing the furnace, the operation of all hot air stoves must be switched to automatic operation. Otherwise, during parallel air blowing operation, the operation of hot air stoves that are not in the air blowing state must be temporarily switched from automatic operation to other operation. The point is that the configuration is such that the operation mode can be switched to any appropriate operation mode.

Next, the present invention will be explained in more detail with reference to the drawings.

FIG. 1 is a block diagram showing one embodiment of the invention, and FIG. 2 is a diagram showing a relay circuit in the embodiment of FIG. In the figure, 1 is an operation schedule control device, 2 is an automatic step-by-step circuit for controlling an operation schedule, 3 is an air blowing command detection circuit, 4 is an air blowing butterfly valve selection circuit, HS is a hot air stove, HV is a hot air valve,
CV is a blower valve, CB is a blower butterfly valve, MV is a cold air valve, MB is a cold air butterfly valve, PCNT and 4
3AD are relays, PAL and ASTP are keep relays, S _P and S _A are set side windings, and R _P and R _A are reset side windings.

Please refer to FIGS. 1 and 2. Studguard parallel air blowing operation of hot air stoves is performed by four hot air stoves 1
This is achieved by setting two of the HS to 4HS in a ventilation state. For example, the blow valve of hot air stove 1HS
Fully open CV ₁ and hot air valve HV ₁ , and the blow valve CV ₂ and hot air valve HV ₂ of hot air stove 2HS to bring both hot air stoves into the blowing state, and then open the blow butterfly valve CB ₁ of hot air stove 1HS or the blow butterfly valve of hot air stove 2HS. By operating either CB ₂ and adjusting its opening degree, the distribution ratio of the air volume passing through both furnaces is changed to control the air temperature. The switching rotation of the four hot air stoves to the blowing state is predetermined, and in this example, the rotation is 1HS → 2HS → 3HS → 4.
It is assumed that the switching is performed in the order of HS. A command to switch the hot air stove to the blowing state is issued from the operation schedule control device 1. This operation schedule control device 1 includes an automatic operation schedule control step circuit 2 and a blowing command detection circuit 3. It continues to advance and issues a blow command when a predetermined time is reached. This ventilation command is detected by the ventilation command detection circuit 3,
It is sent to the blower butterfly valve selection circuit 4. In response to a command from the detection circuit 3, the selection circuit 4 selects the butterfly valves CB of the two hot blast furnaces that are to perform parallel air blowing, and controls the distribution ratio of the amount of air passing through the two furnaces. In addition, each valve of the hot air stove HS has
An open limit switch that operates when fully open and a close limit switch that operates when fully closed are provided.

Now, automatic continuous air blowing status confirmation relay for 2 or more furnaces.
The PCNT operates when the two hot air stoves are automatically in the blowing state according to the switching rotation described above. That is, for example, regarding hot air stove 1HS,
Automatic changeover switch 43A ₁₁ that operates when the furnace is switched to automatic operation and the blow valve of the furnace 1HS
CV ₁ open limit switch contact CV ₁ 0 and hot air valve
When the open limit switches HV ₁ and HV 1 of HV ₁ are all on, the hot air stove 1HS is in an automatic air blowing state, and the same is true for the hot air stove 2HS. Therefore, it is clear from FIG. 2 that the relay PCNT operates when the two hot air stoves 1HS and 2HS are automatically in the air blowing state. Similarly hot stove 2HS
and 3HS, 3HS and 4HS, and 4HS and 1HS are in automatic ventilation mode, the relay
PCNT works. Automatic relay 4 for 4 hot stoves
3AD operates when the automatic changeover switches 43A ₁₂ , 43A ₂₂ , 43A ₃₂ , and 43A ₄₂ that operate when each of the hot air stoves 1HS to 4HS is switched to automatic operation are all on.

The parallel air blowing condition confirmation relay PAL is a keep relay that connects the set side winding S _P and the reset side winding.
It has R _P. The changeover switch 43P is a parallel ventilation selection switch, and when this switch is manually turned on, the operation schedule control device 1 is switched to operation, and the contact 4
3PI _P is now working. Therefore, if all four hot air stoves are in automatic operation, the contact 43AD _P of the relay 43AD is switched, the parallel air blow selection switch 43P is also turned on, and the contact 43PI _P , which indicates the operation of the operation schedule control device 1, is also switched. In this way, the parallel air blowing conditions for the two hot air stoves are satisfied, and the parallel air blowing condition confirmation relay PAL is turned on by operating the set side winding _SP . Next, this relay PAL is restored because one of the four hot air stoves is no longer in automatic operation, so relay 43AD is restored and contact 4
3AD When _P was restored, and the hot air furnace was no longer in the state of automatically blowing air to two or more furnaces in a specified rotation, the relay PCNT was restored and the contact
This is when the PCNT _P is also restored, or when the contact 43PI _P is restored because the operation schedule control device 1 is switched out of operation. In these cases, current flows through the reset side winding R _P and the relay is activated.
PAL will be reset.

The relay ASTP for issuing an automatic stop command of the operation schedule control device 1 is also a keep relay, and has a set side winding S _A and a reset side winding R _A. Air blowing from operation schedule control device 1 →
Contact 3PX closes when a command to pause is issued. Therefore, when this command is issued and contact 3PX turns on, the parallel air blowing condition is established (contact PAL _A is on) and one of the four hot air stoves is not automatic (contact 43AD _A is restored). , the set side winding S _A of relay ASTP is energized, and the first
The contact ASTP (S) in the figure turns on and the operation schedule control device 1 automatically stops. In addition, the automatic stop command of the operation schedule control device 1 is reset when the operation schedule control device 1 is switched to operation, the contact 43PI _A is switched to the opposite side as shown, and the parallel air blowing condition is established (contact PAL _A is on), and when all four hot air stoves are in automatic mode (contact 43AD _A is activated), current flows through the reset winding R _A of relay ASTP, and the contact shown in Figure 1 is activated.
ASTP(R) is turned on, and automatic stepping of the driving schedule control device 1, that is, automatic driving is restarted.

As already explained, in FIG. 1, the automatic stop command signal of the operation schedule control device 1 is
When the contact ASTP (S) is turned on, the reset command signal is input to the operation schedule control automatic step-by-step circuit 2 when the contact ASTP (R) is turned on. When starting parallel ventilation, parallel ventilation conditions must be satisfied (relay PAL operation)
Winding R _A is energized by automatic operation of all four units (relay 43AD operates), contact ASTP (R) is turned on,
An automatic stepping command is input to the driving schedule control automatic stepping circuit 2, and the driving schedule control device starts automatic stepping and issues a blowing command. The blow command detection circuit 3 detects this, and the avoidance circuit 4 selects the blow butterfly valve of the relevant hot air stove to control the air volume distribution. Automatic schedule control device 1
starts automatic stepping and becomes parallel air blowing state as a steady state, even if the conditions for automatic operation of all four hot blast stoves (relay 43AD operation) are no longer present, the operation schedule will continue as long as the S _A winding is not energized. The reset state of the automatic stop command of the control device, that is, the contact
The ASTP(R) holding state continues, and parallel air blowing continues.

When the command for blowing → pause is issued from the operation schedule control device 1 and the contact 3PX is turned on, if there is no condition for all four hot air stoves to be automatic (relay 43AD operates), the S _A winding will be energized. Contact ASTP
(S) is turned on, an automatic stop command is input to the operation schedule control automatic step-up circuit 2, and the operation schedule control device 1 stops automatic step-up and holds the blowing command in the state before the furnace change. Next, when the conditions for automatic operation (relay 43AD operation) for all four hot air stoves are restored, the operation schedule control device 1 resumes automatic advancement,
Performs an operation to switch the hot air stove from blowing air to stopping.

The above explanation has been made for the case where four hot air stoves are installed, but the same applies even if there are four or more hot air stoves.

According to the automatic operation method of the hot air stove according to the present invention, when starting parallel air blowing and when switching any hot air stove from the air blowing state to the idle state in the parallel air blowing state, four hot air stoves are operated. This is done after confirming that the joint automatic operation is in progress, but when the steady state is in the parallel blowing state, other furnaces that are not in the blowing state, that is, in the combustion state or in the dormant state, are The hot stove is
Even if you switch from automatic operation to something else, parallel ventilation will continue without any problems. Therefore, this fact can be utilized to perform maintenance work on a hot air stove that is not in a blowing state, resulting in a significant improvement in the maintainability of hot air stoves compared to the conventional method.

[Brief explanation of the drawing]

FIG. 1 is a block diagram showing one embodiment of the invention, and FIG. 2 is a diagram showing a relay circuit in the embodiment of FIG. In the figure, 1 is an operation schedule control device, 2 is an automatic step-by-step circuit for controlling an operation schedule, 3 is an air blowing command detection circuit, 4 is an air blowing butterfly valve selection circuit, HS is a hot air stove, HV is a hot air valve,
CV is a blower valve, CB is a blower butterfly valve, MV is a cold air valve, MB is a cold air butterfly valve, PCNT and 4
3AD are relays, PAL and ASTP are keep relays, S _P and S _A are the windings on the set side, and R _P and R _A are the windings on the reset side, respectively.

Claims (1)

[Claims] 1. In an automatic operation method for a hot-air stove in which multiple hot-air stoves are operated based on commands from an operation schedule control device to perform static parallel air blowing, each of the multiple hot-air stoves is all switched to the automatic operation side. A first means of confirming that
When the start of parallel air blowing is commanded, if the first means confirms that the all-hot blast stove has been switched to the automatic operation side, the establishment of the parallel air blowing condition is acknowledged and the automatic operation of the operation schedule control device is allowed;
After that, even if the switching confirmation by the first means cannot be obtained, the second means does not cancel the establishment of the air blowing condition by itself, and the operation schedule control device controls the air blowing state of the hot blast stove. When a command to switch the furnace to a dormant state is issued, if the first means does not confirm that the full-hot blast furnace has been switched to the automatic operation side, the operation schedule control device is commanded to stop the automatic operation; At other times, there is a third means that does not issue a command to stop automatic operation even if the switching confirmation by the first means is not obtained, except when starting parallel air blowing and when transitioning to a hot blast stove switch. is an automatic operation method for a hot-blast stove, which is characterized in that it does not necessarily require that the entire hot-blast stove be switched to the automatic mode.