JPS6017565B2 - 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 at the time of abnormality 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 slippage. It is.

For this reason, a device that controls the temperature by spraying cooling water into the blast furnace gas passage is essential, but as is well known, temperature detection has problems with accuracy and detection time delay, and the purpose of temperature control is 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, when 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 as a result, the detected temperature value may show a value that is larger than the actual value. When water level fog control is performed based on the erroneously detected temperature detection value, the green 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 thermoelectric thermometer that does not include a protective tube, it is necessary to take measures to avoid such malfunctions. The present invention is intended to solve such problems, and a first thermoelectric thermometer equipped with a protective tube is provided in the gas passage leading to the dry dust collector, and the clean gas collected by the dry dust collector is A plurality of second thermoelectric thermometers without a protective tube are installed in the passage, and the temperature detected by the second thermoelectric overflow meter with a protective tube and the second thermoelectric thermometer without a protective tube are compared. 1 selected from
If the calculated value does not satisfy the predetermined limit value, the second thermoelectric thermometer is determined to be defective, and the second thermoelectric thermometer is determined to be defective. This invention provides a method for avoiding temperature control malfunctions in a dry dust collector by scanning the temperature detection value of a thermometer and holding the detection line of the second thermoelectric thermometer when an appropriate value is obtained. .

An embodiment of the present invention will be described below based on the drawings.

In FIG. 1, blast furnace gas discharged from the top of a blast furnace 1 passes through a coarse dust collector 2 and a dry crab collector 3, and is guided from a septum valve 4 to a gas holder 6. 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 is connected to the blast furnace from the inlet side of the septum valve 4. Gas 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. susceptible to such influences.

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 to keep the heat-resistant temperature of the furnace cloth below, for example, 210°C or below, and to maintain the fog point, for example, 1.5K.
g/lump of gas does not reach 70q, and the control device 13 controls the attached valve 10 to maintain the specified temperature range, taking into account the temperature detection values of the thermometer 11 and the oven 2. do. 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 sheathed thermocouple thermometer 12 on the exit side of the dry dust collector 3 provides feedback during normal times. Form a control system. Now, let T be the temperature detection value of the thermocouple thermometer 11 on the exit side of the blast furnace 1, and let L be the temperature detection value of the sheathed thermocouple thermometer 12 on the exit side of the dry dust collector 3. At a temperature detection value T, which is below a certain set value and does not reach the temperature of , the calculated value (T, /T2) or (
Considering T2/T,), T,/T2《1.0 or L
/T, >> 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 influence of static electricity due to the omission of the protective tube is considered.

Also, when T, /T2》1.0 or /T,《0.1, it can be judged that the detected temperature value T2 has a great ability to move to a lower temperature side than the actual value, and the thermal fin is due to omitting the protective tube. A failure such as a pair disconnection is possible.

In the present invention, a plurality of the sheathed thermocouple thermometers 12 are installed, and FIG. 2 shows that three sheathed thermocouple thermometers are installed.

That is, the dry dust collector 3 includes a plurality of bag elements 14.
Sheathed thermocouple thermometers 12' and 12'' are respectively provided in two clean gas branch passages 15 and 16 to which the two divided bag element 14 groups are connected, and the clean gas branch passages 15 and 16 are integrated. Twelve sheathed thermocouple thermometers 12', 12'', and 12''' are provided in the clean gas main path 17, and each of these sheathed thermocouple thermometers 12', 12'', and 12''' has a protective tube omitted, and the detected temperature Detection value T2', T2''
, L''' are respectively input to the control device 13, and the largest one is adopted. As shown in FIG.
9, the temperature detection value T of the thermocouple thermometer 11 on the outlet side of the blast furnace 1 and the calculated value of (T./L) are taken. <Set value T, no L《If 1.0 and T, set value T,
/L>>1.0, the scanning circuit 20 is driven. The scanning circuit 20 includes a sheathed thermocouple thermometer 12',
The next temperature detection value n2 is adopted by scanning the detection line of 12'', 12 rivers, and the calculated value (T, /L) is again compared with the normal value in the comparator 21, and the temperature is below the pre-given limit value. When the low value is satisfactory, the detection line is held by the detection line hold circuit 22, and subsequent temperature control is performed based on the temperature detection value T2 of this hold detection line.This eliminates the need for a protective tube. Temperature control malfunctions that may occur due to the use of the sheathed thermocouple thermometer 12 can be avoided. Note that the calculated value based on the temperature detection value T,, T2 is limited to (T, /T2) or (T2/T,). Instead, a calculated value of (T, 10T2) or (T, 1T2) may be adopted.

As described above, according to the present invention, the temperature detection value of the first thermoelectric thermometer equipped with a protective tube, which is provided with a blast furnace gas passage leading to the dry dust collector, and the clean gas supplied to the furnace by the dry dust collector A predetermined calculation value is calculated between one temperature detection value selected from among the temperature detection values of a plurality of second thermoelectric overflow meters provided in the passage without a protective tube, and the calculation value is given in advance. When the specified limit value is not satisfied, the temperature detection values of multiple second thermoelectric thermometers are scanned and the detection line of the temperature detection value where the appropriate value is obtained is held, so the protective tube is omitted. The second thermoelectric thermometer detects the temperature on the exit side of the dry dust collector with high sensitivity and precision, making it possible to control the temperature quickly and reliably, and by eliminating the protective tube, it is possible to eliminate the possibility of false detection. It has now been possible to avoid malfunctions in temperature control, and its industrial value is extremely large.

[Brief explanation of the drawing]

Fig. 1 is a system diagram for explaining the temperature control of the dry type dust collector, Fig. 2 is a configuration diagram showing an example of the arrangement of the thermoelectric thermometer on the exit side of the dry type dust collector of the present invention, and Fig. 3 1 is a block diagram of main parts showing an embodiment of the present invention. FIG. 1...Blast furnace, 3...Dry dust collector, 1
1...Thermocouple thermometer (first thermocouple thermometer),
12, 12', 12'', 12... Sheathed thermocouple thermometer (second thermocouple thermometer), 13... Control device, 18, 19... Arithmetic unit , 20...Scanning circuit, 21...Comparator, 22...Detection line hold circuit. Fig. 1 Fig. 2 Fig. 3

Claims (1)

[Claims] The temperature detected by the first thermoelectric thermometer equipped with a protective tube installed in the blast furnace gas passage leading to the dry dust collector, and the protective tube installed in the clean gas passage filtered by the dry dust collector. Using one temperature detection value selected from the temperature detection values of the plurality of omitted second thermoelectric thermometers, when the blast furnace gas reaches an abnormally high temperature, the temperature is set so that the gas temperature is lowered by liquid spray. When controlling, when the temperature detection value of the first thermoelectric thermometer is below a predetermined setting value, the temperature detection value of the first thermoelectric thermometer and the selected temperature detection value of the second thermoelectric thermometer are A predetermined calculated value is taken, and when the calculated value does not satisfy a predetermined limit value, the temperature detection values of the plurality of second thermoelectric thermometers are scanned, and when an appropriate value is obtained, the temperature detection value is detected. A method for avoiding temperature control malfunction of a dry dust collector characterized by holding a line.