JPS6017566B2 - How to avoid temperature control malfunction of dry dust collector - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a method for avoiding temperature control malfunctions in temperature control during abnormal conditions in a blast furnace when a dry dust collector is used.

In general, dry dust collectors are not suitable for high temperatures, and when used in energy recovery turbine equipment that uses blast furnace gas, they cannot withstand excessive increases in gas temperature caused by abnormalities such as blast furnace blow-through or slip. It is something.

For this reason, it is essential to have a device that controls the temperature by misting cooling water into the blast furnace gas passage, but as is well known, temperature detection has problems with accuracy and detection time delay. The types of thermometers that can be used for this purpose are limited; for example, a sheathed thermocouple or the like must be used and a protective tube must be omitted in order to avoid delay in detection time. However, if a temperature detection method that does not include a protective tube is used, it is susceptible to the effects of static electricity, etc., and as a result, the generated current value increases, and the detected temperature value may show a value that is larger than the actual value. When water mist control is performed based on the detected temperature value, the moisture content of the blast furnace gas increases and eventually reaches a supersaturated state. If a dry dust collector using a bag (furnace cloth) is used as a dust collector, the furnace cloth will become clogged due to oversaturation of moisture, which will have a fatal effect on subsequent use. Therefore, when using a heat-dew thermometer that does not require a protective tube, it is necessary to take measures to avoid such malfunctions.The present invention is intended to solve this problem. In addition to the thermoelectric thermometer installed in the clean gas passage for temperature control without a protective tube, a thermoelectric thermometer with a protective tube is installed to measure the temperature detected by the thermoelectric thermometer without the protective tube. The present invention provides a method for avoiding temperature control malfunctions in a dry dust collector, which constantly checks the temperature detected by a thermoelectric thermometer equipped with a protective tube.

An embodiment of the present invention will be described below based on the drawings. 1st
In the figure, blast furnace gas discharged from the top of a blast furnace 1 passes through a coarse dust collector 2 and a dry dust collector 3, and is guided from a septum valve 4 to a gas holder 5. Reference numeral 6 denotes a power generation facility installed in parallel with the septum valve 4, which is connected to the in-house power grid and takes the load.The energy recovery turbine 8 that drives the generator 7 supplies blast furnace gas from the inlet side of the septum valve 4. is introduced and driven.

In this case, the septum valve 4 is closed and the furnace top pressure is appropriately adjusted on the turbine side and kept constant. The blast furnace gas that has driven the energy recovery turbine 8 is returned to the outlet side of the septum valve 4. Further, the coarse particle dust collector 2 is provided with a cooling fluid injector 9, and a cooling fluid is sprayed through an electric valve 10. Reference numeral 11 denotes a normal type thermocouple thermometer equipped with a protective tube, which is installed in a gas passage leading to the dry dust collector 3, for example, between the blast furnace 1 and the coarse dust collector 2. Although it involves errors and detection time delays, it is a type of thermometer that is not affected by static electricity. 12 is a sheathed thermocouple thermometer that is installed in the clean gas passage filtered by the dry dust collector 3 and directly detects the gas temperature without using a protective tube, and although it has high sensitivity and accuracy, Easily affected by static electricity, etc.

In the case of the bag-type dry dust collector 3, the important factors in controlling the temperature using the thermometers 11 and 12 are that the heat-resistant temperature of the furnace cloth is kept below, for example, 210°C or less, and that the temperature is kept at a temperature of 1.5K or less, for example.
9/Sakaki gas does not reach 70 qC, and the control device 13 takes into consideration the temperature detection values of the thermometers 11 and 12 and controls the electric valve 10 to maintain the temperature within the above temperature range, for example. For example, the thermocouple thermometer 11 on the exit side of the blast furnace 1 forms a feedforward control system in the event of an abnormality such as blast furnace blow-through or slip, and the sheath thermocouple thermometer 12 on the exit side of the dry dust collector 3 forms a feed forward control system during normal times. Form a feedback control system. Reference numeral 14 denotes a normal type thermocouple thermometer equipped with a protective tube, which is installed in the clean gas passage filtered by the dry dust collector 3, and has a certain amount of error similar to the thermocouple thermometer 11 on the blast furnace side. Although it involves a detection time delay, it is a type of thermometer that is not affected by static electricity, etc., and is used for checking the sheathed thermocouple thermometer 12 that does not have a protective tube.

Now, let the temperature detection value of the sheathed thermocouple thermometer 12 for main temperature control be T2, and the temperature detection value of the checking thermocouple thermometer 14 be T4, and the calculated value (L/T2) or (T2/T4 ), when T4/T2《1.0 or T2/T4》1.0, it can be determined that the detected temperature value E2 has a large error toward the higher temperature side than the actual value, and the protective tube is omitted. This may be due to the effects of static electricity.

In addition, when T4/T2》1.0 or T2/T4《1.0, it can be determined that the detected temperature value T2 has a large error toward the lower temperature side than the actual value, and the temperature difference caused by omitting the protective tube can be determined. A malfunction such as a wire breakage is possible.

Therefore, as shown in FIG. 2, a calculated value (T4/T2) is created using the calculating unit 15 in the control device 13, and this is constantly compared with an appropriate value in the comparator 16, and the value is set to a pre-given limit value. When the appropriate value satisfies the following, the temperature detection value n of the thermocouple thermometer 11 on the blast furnace side equipped with a protective tube, and the temperature of the sheathed thermocouple thermometer 12 with the protective tube omitted on the dry dust collector side. Normal temperature control is performed using the detected value T2.

However, if the pre-given limit value is not satisfied, such as T4/T2《1.0 or T-horn T2》1.0, the emergency device 17
to drive. By driving this emergency device 17, for example, the fluid lighting operation by the motor-operated valve 10 is stopped or the fluid lighting operation is prevented. This makes it possible to avoid temperature control malfunctions that may occur due to the use of the sheathed thermocouple thermometer 12 without the protective tube. 3 and 4 show another embodiment of the emergency device 17. FIG.

In this case, a plurality of sheath thermocouple thermometers 12 for temperature control are provided, and FIG. 3 shows three sheath thermocouple thermometers 12 provided. That is, the dry dust collector 3 is formed of a plurality of bag elements 18, and the bag element 18 is divided into two parts.
Sheathed thermocouple thermometers 12' and 12'' are provided in the two clean gas branch passages 19 and 20 to which the group is connected, respectively, and a sheathed thermocouple thermometer is provided in the clean gas main passage 21 where the clean gas branch passages 19 and 20 are integrated. A pair thermometer 12'' is provided, and each of these sheathed thermocouple thermometers 12', 12'', and 12 has a protective tube omitted, and the detected temperature value n2' is
, L'', L... are each input to the control device 13, and the largest one is adopted. Also, a checking thermocouple thermometer 14 equipped with a protective tube is installed, for example, in the clean gas main passage 21. Temperature detection values T2', T2'', L'''
The temperature detection value n2 adopted from the temperature detection value n2 and the temperature detection value L of the check thermocouple thermometer 14 are computed by the computing unit 15 in the same manner as described above, and the computed value is compared with the thin value by the comparator 16 to determine the limit value. If not satisfied, the scanning circuit 22 is driven. The scanning circuit 22 includes a sheathed thermocouple thermometer 12',
The next temperature detection value T2 is used by scanning the detection lines of 12'' and 12''', and the calculated value (T4/T2) is compared with the regular value in the comparator 23, and the temperature is below the pre-given limit value. When the normal value is satisfied, the detection line is held in the detection line hold circuit 24, and subsequent temperature control is performed based on the temperature detection value n2 of this hold detection line.

This makes it possible to avoid temperature control malfunctions that may occur due to the use of the sheathed thermocouple thermometer 12 without the protective tube. Note that the calculated value based on the temperature detection values T4 and T2 is (T4/
T2) or (T2/T4),
The calculation of (T4 + T2) or (T2 - T4) may be adopted. As described above, according to the present invention, the dry type dust collector uses the temperature detection value of the first thermoelectric thermometer, which is provided in the clean gas passage fed to the furnace by the dry type dust collector and does not include a protective tube, as the main control value. In the temperature control method, a second thermoelectric thermometer provided with a protective tube is provided in the clean gas passage separately from the first thermoelectric overflow meter, and
Take the predetermined calculated value from the temperature detection value of the thermoelectric thermometer,
In order to activate the emergency device when the calculated value does not satisfy the pre-given limit value, the temperature at the outlet side of the dry dust collector is measured with high sensitivity using the first thermoelectric overflow meter that does not require a protective tube.
It is possible to perform temperature control quickly and reliably through highly accurate detection, and by eliminating the protective tube, it is possible to avoid malfunctions in temperature control due to false detection, which are likely to occur, and its industrial value is extremely large.

[Brief explanation of the drawing]

Fig. 1 is a system diagram showing an embodiment of the present invention, Fig. 2 is a block diagram of main parts explaining its operation, and Fig. 3 shows another arrangement of the thermoelectric thermometer on the exit side of the dry dust collector. Configuration diagram, 4th
The figure is a block diagram of main parts showing another embodiment of the emergency device. 1...Blast furnace, 3...Dry dust collector, 9
......Cooling fluid injector, 10...Electric valve, 12, 12', 12'', 12'''...Sheath thermocouple thermometer (first thermal fin type thermometer), 13...
... Temperature device, 14 ... Thermocouple thermometer for checking (second thermocouple thermometer), 15 ... Arithmetic unit, 16, 23 ... Comparator , 17... Emergency device, 22... Scanning circuit, 24...
...Detection line hold circuit. Figure 2 Figure 4 Figure 1 Figure 3

Claims (1)

[Claims] 1. When controlling the temperature using the temperature detection value of the first thermoelectric thermometer without the protective tube installed in the clean gas passage filtered by the dry dust collector as the main control value, the A second thermoelectric thermometer equipped with a protective tube is installed separately from the first thermoelectric thermometer, and a predetermined calculated value taken from the temperature detection values of the first and second thermoelectric thermometers is given in advance. A method for avoiding malfunction of temperature control in a dry dust collector, characterized by operating an emergency device when a limit value is not satisfied.