JPS6113531B2 - - Google Patents

Description

[Detailed description of the invention]

The present invention deals with the combustion gas of a hot stove, namely blast furnace gas (hereinafter abbreviated as B gas) and coke oven gas (hereinafter abbreviated as C gas).
The present invention relates to a combustion gas control method for controlling the calorie of a mixed gas (hereinafter abbreviated as M gas) consisting of M gas (hereinafter abbreviated as M gas). Hot-blast stoves were operated in parallel, with switching from one unit to two units burning (commonly known as ``starting'') and two units to one unit burning (commonly known as ``shutdown'') (commonly known as ``furnace change''). There is. By the way, in the conventional combustion gas control method, as shown in FIG. The output is input to a C gas flow rate regulator 4, the calorie of M gas is measured by a calorie meter 5, and the measurement result is input to a calorie regulator 6. This calorie regulator 6 compares and discriminates the measurement result of the calorie meter 5 with a preset setting value, calculates the mixing ratio of C gas to B gas, and outputs the calculated value from the calorie regulator 6. Input to the M gas ratio controller 3. The M gas ratio controller 3 uses the B gas flow rate output from the B gas flow meter 1 and the C gas mixing ratio from the calorie controller 6 to calculate the required amount of C gas, and calculates the required amount of C gas. Based on the calculated value, the C gas flow rate control valve 7 is adjusted to control the calorie of M gas. However, in the conventional combustion gas control method, the calorie meter 5 burns M gas and measures the calories, and the C gas flow rate is adjusted based on the measurement results. Large calorie fluctuations are unavoidable due to the delay in opening and closing of the flow control valve 7 and the delay in response of the calorimeter 5. This point will be explained based on FIGS. 1 and 2. On the downstream side of the calorimeter 5, the pipe line is branched into a plurality of lines and connected to the respective hot air stoves F ₁ , F ₂ and F ₃ .
Although not shown, a hot air stove _F4 or lower may be provided.
Although the configurations on the hot-blast stoves F ₂ and F ₃ are omitted, they are the same as the configuration on the hot-blast stove F ₁ side, and are each equipped with a cutoff valve equivalent to the cutoff valve 12 . Now, let's consider a case where the furnace is changed from a state where only hot air stove F ₃ is burning to hot air stove F ₁ . At the start of furnace replacement, the shutoff valve 12 on the hot blast stove _F1 side, which has been closed until now, is opened. At the same time, the B gas flow rate control valve 8, which until now had an opening degree necessary to supply B gas for one hot stove, is opened wide so that a larger amount of B gas can be supplied. B like this
The opening degree of the gas flow rate control valve 8 is normally automatically adjusted in accordance with the pressure within the main pipe. That is, when the cutoff valve 12 on the hot air stove _F1 side is opened, the B gas flow rate control valve 8 is opened wide in order to prevent the pressure in the main pipe from decreasing and keep it constant. In this way, at the start of furnace change, the B gas flow control valve 8 increases its opening degree in immediate response to the release of the cutoff valve 12, and a large amount of B gas flows out.
Supply gas. However, since the C gas flow rate control valve 7 is adjusted based on the calorie measurement results obtained by burning M gas as described above, it is adjusted immediately in response to the opening of the shutoff valve 12 at the start of furnace replacement. I can't do it. In other words, at the start of furnace replacement, C
The gas flow rate control valve 7 opens only at the opening degree necessary to supply C gas for one hot air stove, and then opens wide enough to supply C gas for two hot air stoves after a delay. It will be. Therefore,
At the start of furnace replacement, the M gas contains only the amount of C gas for one hot stove, and the calorie of the M gas is lower than the set value. Next, let us consider a case where the state in which the two hot-blast stoves F ₁ and F ₂ are burning is changed to combustion in only the hot-blast stove F ₂ , that is, when the furnace change is shut off. In this case, by closing the cutoff valve 12 on the hot air stove _F1 side (the cutoff valve on the hot air stove _F2 side is open. However, as mentioned above, the opening degree adjustment of the C gas flow rate control valve 7 is delayed, so when the M gas is shut off, the amount of C gas for two hot blast stoves is contained in the M gas. The calorie of the gas becomes higher than the set value.In this way, in the conventional control method that relies on calorie feedback control, the C gas flow control valve 7
As a result of the time delay involved in the response, the calorie of M gas fluctuated greatly at the start and shutdown of furnace replacement, as shown in Figure 2. As a result, a stable hot air temperature cannot be obtained, resulting in abnormal temperature rise inside the hot blast stove, destruction of heat storage bricks due to temperature drop, and disruption of the furnace replacement sequence.
There was a problem of reduced efficiency due to fluctuations in the air-fuel ratio of hot blast stoves. SUMMARY OF THE INVENTION An object of the present invention is to provide a method for controlling combustion gas in a hot blast stove, which can reduce fluctuations in the calorie of M gas when changing the furnace. The configuration of the present invention will be described below based on the embodiments shown in FIGS. 3, 4, and 5. In addition, in FIG. 3, hot air stoves F ₂ and F ₃ are omitted from illustration. The output of the B gas flow rate signal from the B gas flow meter 1 is input to the M gas ratio regulator 3, and the output of the C gas flow rate signal from the C gas flow meter 2 is input to the C gas flow rate regulator 4. On the other hand, the calorie of M gas is measured by the calorie meter 5, and the measurement result is input to the calorie controller 6. The calorie regulator 6 compares and determines the preset value and the measurement result sent from the calorie meter 5, corrects and calculates the mixing ratio of C gas to B gas, and uses the calculated value from the calorie regulator 6. The output is sent to the M gas ratio regulator 3. In the M gas ratio regulator 3, the mixed amount of C gas is calculated from the output of the B gas amount from the B gas flowmeter 1 and the output of the mixing ratio of C gas to B gas from the calorie regulator 6, The C gas amount V ₁ from the M gas ratio regulator 3, which is the calculated value, is input from the calculator 9. On the other hand, a furnace change notice signal is taken out from the furnace change control device 10, and this furnace change notice signal is sent to the corrector 11, which corrects the amount of C gas in the M gas in accordance with the timing of the furnace change. Correction C gas amount signal
V ₂ and V ₃ C are generated, and the outputs V ₂ and V ₃ are input to the arithmetic unit 9. Since the operation of a hot air stove consists of a certain time chart, the furnace is changed periodically, and the furnace change advance notice signal sent from the furnace change control device 10 includes a start signal and a cutoff signal. The start signal is transmitted to a combustion start corrector 111 in the corrector 11.
The cutoff signal is converted into a corrected C gas amount signal V ₂ by a combustion cutoff corrector 112 in the corrector 11, and is sent to a corrected C gas amount signal V ₃ , respectively. The calculator 9 receives a signal V ₁ of the amount of C gas in the M gas from the M gas ratio regulator 3, a signal V ₂ of the correction amount of C gas in the M gas from the combustion start corrector 111, Calculation V ₀ with signal V ₃ of C gas correction amount in M gas from the combustion cutoff corrector 112
=V ₁ +V ₂ -V ₃ is performed, and this calculated value V ₀ is sent to the C gas flow rate regulator 4. In the C gas flow rate regulator 4, the output of the C gas amount from the C gas flow meter 2 and the calculated value _V0 sent from the calculator 9 are compared and determined, and based on this determined value, the C gas flow rate control valve is adjusted. The opening degree of 7 is adjusted. As a result, as shown in FIG. 5, the C gas flow rate outputs of the calculator 9 and the C gas flow rate regulator 4 are hatched in FIG. The follow-up delay of valve 7 is eliminated. That is, the C gas flow rate control valve 7 is adjusted in opening so that the C gas flow rate is higher than usual at the start of furnace replacement, and is quickly throttled down at the time of shutoff so that the calorific value of M gas does not become high. As a result of the experiment, when a blast furnace of 5050 m ³ was operated under the conditions shown in Table 1, the range of calorie fluctuations when changing the furnace between the conventional control method and the control method of the present invention was as shown in Table 2.

【table】

[Table] The present invention has the configuration described above, and uses the furnace change advance notice signal to generate the corrected C gas amount signal V ₂ issued from the combustion start corrector in the corrector in accordance with the timing of furnace change. , the corrected C gas amount signal _V3 issued from the combustion cutoff corrector, and the C of the calorie feedback control system output from the M gas ratio regulator.
Perform the calculation V ₀ = V ₁ + V ₂ − V ₃ with the gas amount signal V ₁ ,
Since the opening of the C gas flow control valve is adjusted based on the discrimination value between this calculated value V ₀ and the output from the C gas flow meter, the follow-up delay of the C gas flow control valve is eliminated. , has the effect of significantly reducing the calorie fluctuation of M gas, and in turn can prevent various troubles associated with calorie fluctuation of M gas.

[Brief explanation of the drawing]

Fig. 1 is an explanatory diagram of the conventional control method, Fig. 2 is a time chart of the same, Fig. 3 is an explanatory diagram of an embodiment of the present invention, Fig. 4 is a detailed view of the same main part, and Fig. 5 is the same. It is a time chart. 1...B gas flowmeter, 2...C gas flowmeter, 3
...M gas ratio regulator, 4...C gas flow rate regulator, 5...Calorie meter, 6...Calorie regulator,
7... C gas flow control valve, 8... B gas flow control valve, 9... Arithmetic unit, 10... Furnace change control device, 11
...Corrector.

Claims (1)

[Claims] 1 In a combustion gas control method that adjusts the mixing ratio of coke oven gas to blast furnace gas in a mixed gas that is combustion gas, the combustion start is performed during the coke oven gas flow rate signal V ₁ from the mixed gas ratio controller and the furnace change notice signal. Corrected coke oven gas amount signal from the compensator
The calculation V ₀ =V ₁ +V ₂ −V ₃ is performed by a calculator using V ₂ and the corrected coke oven gas amount signal V ₃ from the combustion shutoff corrector, and then the flow rate signal from the coke oven gas flow meter and the above calculation are performed. 1. A method for controlling combustion gas in a hot blast oven, characterized in that the value V ₀ is compared and determined by a coke oven gas flow rate regulator, and the opening degree of a coke oven gas flow rate control valve is adjusted based on the determination result.