JPS6119709A - Controlling method of temperature on occurrence of blow-by in blast furnace - Google Patents

Abstract

PURPOSE:To protect effectively a dry-type dust collector, by injecting water into the upper part inside a blast furnace and a primary coarse-grained dust catcher when extraordinary blow-by of a blast furnace gas is detected in a system of generating electricity by a turbine using the blast furnace gas. CONSTITUTION:When extraordinary blow-by in a blast furnace 1 is detected by a blast furnace gas flow meter 8 when a dry-type dust collector 4 is operated, a furnace top water spray pump 10 and a coarse-grained dust collector water spray pump 11 are started through a main control unit 9, and thereby water spray is started to a furnace top and a coarse-grained dust catcher 2. The quantity of cooling water sprayed to the furnace top is controlled by adjusting the opening of a flow adjusting valve 16 through a furnace top water spray quantity control unit 15 based on the temperature of a furnace top gas and the quantity of a generated gas. The timing of the start of water spray to the coarse-grained dust catcher 2 is determined by calculating the time of arrival of a high-temperature gas from the flow rate of the generated gas and the internal capacity of an intermediate duct 21, and the quantity of water sprayed to this collector is controlled by adjusting a spray water flow adjusting valve 18 through a coarse-grained dust collector water spray quantity control unit 17 on the basis of an inlet thermometer 19 and an outlet thermometer 20 of the dust catcher 2 and the quantity of the generated gas.

Description

[Detailed Description of the Invention] [Industrial Application Field] The present invention relates to a method for controlling the temperature at the time of occurrence of blast furnace atrium when using a dry dust collector, and in particular, the present invention relates to a method for controlling the temperature at the time of occurrence of blast furnace atrium when a dry dust collector is used. relates to a temperature control method that can achieve effective protection of dry dust collectors during outbreaks.

[Prior Art] It is common practice to generate electricity using a turbine to recover the pressure energy of the furnace top gas. However, the furnace top gas is 10 to 30 g/N when it is still generated.
If the blast furnace is used as it is for a turbine, etc., it will cause problems such as wear of the turbine.On the other hand, during blast furnace operation, abnormalities such as stairwells may occur on rare occasions, causing the top gas to become abnormally high temperature. Therefore, in order to solve these problems, a method has been adopted in which the top gas is passed through a wet dust collector to remove dust and cool the top gas at the same time. However, when the furnace top gas is passed through a wet dust collector, the temperature of the furnace top gas decreases rapidly (70 to 100℃) and the pressure also decreases, making it impossible to effectively recover the energy held by the furnace top gas. There was a problem.Therefore, various proposals have been made to use a dry type dust collector instead of a wet type dust collector, and it has already been put into practical use in small blast furnaces with stable operation.However, In large blast furnaces, there are problems such as high-temperature gas generated due to the blow-through, which can damage dust collectors, especially dry dust collectors such as bag filters, so consideration must be taken to deal with this problem.For these reasons, Under normal conditions, a dry dust collection method is used to prevent a drop in collection efficiency due to a drop in the temperature of the furnace top gas, and in the event of an abnormality, the abnormally high temperature of the furnace top gas is cooled by spraying cooling water, etc. to protect the dust collector. For example, methods have been proposed to
JP-A-54-40207, JP-A-53-140206
No., JP-A-54-81107, JP-A-55-9190
No. 3, JP-A-56-127184, JP-A-57-15
It is disclosed in Japanese Patent No. 8307.

Furthermore, Japanese Patent Application Laid-Open No. 161010/1983 by the present applicant proposes a blast furnace gas flow rate measurement for measuring the size of blast furnace atrium. However, even in this invention, the detection of blow-through is performed based on the gas temperature.
The gas flow rate is only for controlling the amount of watering.

In addition, in Japanese Patent Application Laid-open No. 57-161009, it is proposed to spray water inside the blast furnace and sprinkle water to remove secondary coarse particles in response to the atrium. It is applied to blast furnaces with water injection equipment and a large amount of water injection relative to the blast furnace volume.

[Problems to be Solved by the Invention] In all of the above-described methods, abnormalities in blast furnace operation, such as blow-through, are detected by measuring the furnace top temperature. It is true that when a blast furnace abnormality such as a stairwell occurs, the furnace top gas temperature rises markedly, so abnormalities in furnace operation can be reliably detected by monitoring the furnace top temperature. However, in large high-pressure blast furnaces, the gas temperature rises slowly and starts to rise very gradually, but in the atrium, the temperature decreases more slowly due to the large amount of gas, and after detecting the gas temperature rise, the temperature starts to rise very gradually. Even if treatment (water sprinkling) is performed, control may be delayed and the gas temperature may exceed the upper limit of the control value. In such a case, even if a protective means for the dry dust collector is provided in case of an abnormality in blast furnace operation, it will be of no use at all.The present invention is designed to solve such problems. The purpose of this system is to quickly detect the blow-through in order to quickly respond to the rise in temperature of the blast furnace due to the blow-through, and to provide a method for controlling the temperature when the blast furnace blow-through occurs. .

(Means for Solving the Problems) In order to solve the above problems, the present invention provides a blast furnace gas cleaning system including at least a primary coarse particle dust removal device and a dry dust collector, based on at least the blast furnace gas flow rate. The blast furnace atrium is characterized in that the atrium detects an abnormal atrium, and in response to the detection, injects water into the upper part of the blast furnace and the temporary coarse dust removal device.

(Function) According to the research conducted by the inventors of the present invention, as shown in FIG. 4, the effect of an abnormality in blast furnace operation, such as a stairwell, appears most quickly on changes in the furnace top pressure. however,
It is difficult to detect the top pressure of the furnace because the range of fluctuation is narrow and the rate of change is not much different from normal pressure equalization or raw material input. On the other hand, although changes in gas temperature are noticeable and easy to detect, the response to changes in gas temperature is slow, making the atrium unsuitable for detection. On the other hand, since the amount of blast furnace gas increases significantly immediately after a blow-through occurs, blow-through can be detected quickly and reliably by monitoring the blast furnace gas flow rate.

The present invention has been developed by focusing on the rapid and significant change in the amount of blast furnace gas over time, as described above, and by detecting the blast furnace atrium based on at least the blast furnace gas flow rate. This method reliably detects a blow-through without a substantial time delay after its occurrence.

On the other hand, focusing on the blast furnace gas temperature, the blast furnace gas temperature reaches its peak 2 to 3 minutes after the blowout occurs, and at the outlet of the temporary coarse dust removal equipment, the blowout reaches its peak after a time delay of approximately 30 seconds after the occurrence. The inventors' research has revealed that the temperature begins to rise. Therefore, by quickly sprinkling water into the blast furnace based on the detection based on the amount of blast furnace gas, the blast furnace gas can be cooled before the temperature of the blast furnace gas substantially rises, and a significant temperature rise can be suppressed. Additionally, since the gas flow rate in a large-capacity blast furnace is extremely slow, the amount of water that comes in contact with a given amount of gas can be increased compared to when water is injected through a conduit, allowing for effective cooling. .

(Example) FIG. 1 is a schematic diagram showing an embodiment of the present invention.

In the embodiment shown in FIG. 1, the gas generated from the blast furnace 1 is connected in parallel to a temporary coarse dust removal device 2 of the gravity settling type and a wet dust collector 3 such as a Venturi scrubber or a wet electrostatic precipitator. Dust is removed by a cleaning system comprising a dry dust collector 4 such as a bag filter. The wet type dust collector 3 and the dry type dust collector 4 are selectively connected to each other, and normally the blast furnace 1 → − next dust collector 2 is connected.
→A system consisting of a dry dust collector 4 is used. A furnace top pressure recovery turbine 5 is installed on the outlet side of each dust collector 3 and 4.
is connected.

As will be described in detail later, the blast furnace 1 is equipped with a water spray device, which sprays water onto the upper part of the blast furnace as necessary. Similarly, the secondary coarse particle dust removing device 2 is also provided with a water spraying device to spray water into the dust removing device 2.

A furnace top pressure gauge 6 and a furnace top gas thermometer 7 are provided at the top of the blast furnace 1, and a blast furnace gas flow meter is provided near the outlet of the dry dust collector 4. Furnace top pressure gauge 6, furnace top gas thermometer 7
The blast furnace gas flow meter 8 is controlled via the main controller 9 by a furnace top water spray pump 10, a secondary dust removal device water spray pump 11, and a switching valve 12 between the wet type dust collector 3 and the dry type dust collector 4.
Continued on 13°14. The blast furnace gas thermometer 7 and the blast furnace gas flow meter 8 are further connected to a flow rate control valve 16 via a furnace top water spray amount control device 115, and the blast furnace gas flow meter 8 is further connected to a primary dust removal device water spray amount control device 17. and is connected to the flow rate control valve 18. - The secondary dust remover N2 is further provided with an inlet thermometer 19 on the inlet side and an outlet thermometer 20 on the outlet side, -
Next dust removal device water spray amount control device 17 through flow control valve 1
Connected to 8.

With the above configuration, the gas generated from the blast furnace 1 is primarily dust-removed by the coarse particle dust collector 2, and then usually dust-removed by the dry dust collector 4, and then supplied to the furnace top pressure recovery turbine 5. . At this time, when a blow-through occurs in the blast furnace 1, the blow-through is instantaneously detected by the furnace top pressure gauge 6, the furnace top gas thermometer 7, and the gas flow meter 8. When detecting atriums, it is not necessarily necessary to import data from all of these sources.
It is sufficient that at least data from the gas flow meter 8 is taken in.

When blow-through occurs when the dry dust removal device is used, the furnace top water spray pump lO and the coarse dust collector water spray pump 11 are activated via the main control device 9 at the same time as the blow-through is detected, and the water spray pump 11 of the coarse dust collector is activated. Water spray starts.

The amount of cooling water is controlled by adjusting the opening degree of the flow rate control valve 16 via the furnace top water spray amount control device 15 based on the furnace top gas temperature and the amount of generated gas.

The start timing of water spraying to the coarse particle dust collector 2 is determined by calculating the arrival time of the high-temperature gas from the generated gas flow rate and the internal volume of the duct 21 in the middle.

Further, the spray amount is based on the inlet thermometer 19 and outlet thermometer 20 of the dust removal device 2 and the amount of generated gas.

The coarse particle dust removal device is controlled by adjusting the spray water flow rate control valve 18 via the water spray amount control device 17.

Furthermore, at the same time as the detection, the gas valves 12, 13 and 14 can be automatically operated to switch the gas flow from the dry type dust collector 4 to the wet type dust collector 3. In this case, the dry dust collector 4 such as a bag filter can be completely protected from high-temperature gas.

When detecting blow-through based on the amount of gas generated, for example, a value slightly higher than the peak value during top blast furnace gas recovery in normal operation is used as a reference, and the amount of gas exceeding this value is measured and blow-through is detected during noodle production. When wind is reduced, it is necessary to lower the standard value in accordance with the decrease in the amount of gas blown into the blast furnace. Further, the installation position of the gas flow meter 8 is preferably selected from a position where there is no disturbance in the recovery of the blast furnace 5, for example, on the outlet side of the dry dust collector 4.

The change in the gas pressure in the turbine downstream duct 22 is a pressure change accompanying an increase in the amount of gas, so it is basically synchronized with the change in the amount of blast furnace gas. Therefore, it can be used as a backup means for detecting an atrium.

Next, water injection into the blast furnace will be explained.

FIG. 2 is an explanatory diagram showing an outline of a cooling water spray device installed in the blast furnace I according to the present invention. The cooling water spray device according to the present invention includes a spray nozzle 10 whose tip is located between a large bell 101 and an armor plate 102.
3, a cooling water spray pump 10, and a flow control valve 16.

For example, eight spray nozzles 103 are provided in the circumferential direction within the blast furnace I. The specifications of the spray nozzle 103 are, for example, configured to be a pressure spray type, and the atrium is purged with N2 to prevent clogging, and the atrium is sometimes 30
Water is injected T/H times. The requirements for the spray nozzle 103 are that water does not splash on the large bell 101 and the arm plate 1O2, that the charged material does not collide with the nozzle, and that it can spray uniformly in the circumferential direction. Therefore, the shape of the spray nozzle 103 is formed as shown in FIG. 3, for example. In this case, the spray shape becomes fan-shaped.

The amount of spray water is controlled, for example, as follows.

(1) At the same time as the stairwell was detected, a fixed amount of spray was started at 2407/H (30T/H, wood x 8), and the furnace top gas temperature was 35
It will stop when the temperature drops below 0°C (ON/OFF control).

(2) No water flow control is performed.

(3) The furnace top spray is responsible for the base part of gas temperature control, and the coarse dust collector spray performs final temperature control.

(Effects of the Invention) As described above, according to the present invention, the time delay at the time of detection of the blowhole can be substantially eliminated, so that the temperature control equipment of the furnace top and coarse particle dust removal equipment can be set up quickly. It is possible to raise the temperature and control the temperature. Furthermore, since the gas temperature is controlled at the top of the furnace, the controllability of water spraying is improved, and the amount of water sprayed by the coarse particle dust remover on the downstream side can be reduced. Furthermore, if the atrium is switched to a wet type dust collector immediately after detection, the safety of the dry type dust collector is completely ensured. As a result, it becomes possible to install a dry dust removal device in a large, high-pressure blast furnace. As a result, the □-bin inlet pressure is 0,
2 kg/cnf increase, turbine inlet gas temperature is 70℃
~100℃ higher than before.

As a result, the energy of the turbine inlet gas increases by about 30%. Furnace top pressure 2, 5 kg/ctn' internal volume 4
In the case of an 800rn' blast furnace, the generator output is 4000~50
This is an increase of 0.00KW, which is very effective.

[Brief explanation of the drawing]

Fig. 1 is a schematic diagram of the present invention, Fig. 2 is an explanatory diagram showing an example of the top water injection equipment used in the present invention, and Fig. 3 is an explanatory perspective view showing the shape of the spray nozzle used in the present invention. , Figure 4 is a graph showing the relationship between changes in furnace top pressure, furnace top gas temperature, and furnace top gas flow rate and blow-through.

Claims (1)

[Claims] (1) In a system that supplies blast furnace gas to a furnace top pressure recovery turbine to generate electricity, in a blast furnace gas cleaning system equipped with at least a primary coarse dust remover and a dry dust collector, abnormal blow-through occurs based on at least the blast furnace gas flow rate. A method for controlling temperature when blow-through occurs in a blast furnace, characterized in that water is injected into an upper part of the blast furnace and a primary coarse dust removal device in response to detection of blow-through.