JPH0698256B2 - Method and apparatus for controlling blowdown gas flow rate of louver type dust collector in exhaust gas treatment apparatus - Google Patents

Description

Description: TECHNICAL FIELD The present invention relates to a method and a device for controlling a blowdown gas flow rate of a louver type dust collector in an exhaust gas treatment device having a louver type dust collector. It is a thing.

[Conventional technology and its problems]

The louver type dust collector has been used for a long time because it has a small pressure loss, has a simple structure, and has a relatively small effect on the dust collection efficiency even if the inlet dust concentration changes significantly. The separation limit particle size is relatively large as compared with the dust collector, and it is difficult to obtain a sufficiently clean gas with the louver type dust collector alone, so the range of use was not so wide.

However, since the structure is simple and the pressure loss is small, it can be sufficiently used for the high temperature, large capacity, pre-collector of high dust-containing gas, etc. generated in the steel making process, etc., and it can be expected to make the equipment compact and easy to maintain. (Prior art example "dust collector" published by Nikkan Kogyo Shimbun).

The dust collection efficiency of the louver-type dust collector is affected by the blowdown flow rate extracted together with the coarse dust particles, and increases as the blowdown gas amount increases. The louver-type dust collector having such characteristics has been conventionally used in the arrangement shown in FIG. 4, and the blowdown gas of the louver-type dust collector 1 is installed separately from the main air exhauster 2. It was sucked by the auxiliary fan 3. In the exhaust gas treatment equipment as shown in FIG. 4, it is difficult to always obtain a constant dust collection rate because the blowdown gas amount changes with the change in the treatment gas amount.

For this reason, the ironmaking process, especially the operation, becomes batch operation,
It was never actually used in the steelmaking process used in converters, etc., where the amount of generated gas greatly changes in a short time.

[Object of the Invention]

The present invention has been made to solve the above problems, and controls the blowdown gas flow rate of a louver-type dust collector so that the dust collection efficiency of the louver-type dust collector can be stably maintained. It is an object of the present invention to provide a method and an apparatus thereof.

[Means for Solving the Problems]

A blowdown gas flow rate control method for a louver-type dust collector in an exhaust gas treatment apparatus, which is one of the present invention for solving the above-mentioned problems, provides a louver-type dust collector in an exhaust gas duct connected to a gas cooler. , A secondary dust collector is installed downstream of it,
Further, in an exhaust gas treatment device having a main exhaust fan downstream thereof, a pressure detector provided at the inlet of the gas cooler is connected to the flow control mechanism provided in the blowdown system of the louver type dust collector to control the flow rate. It is characterized in that the mechanism is operated according to the change of the gas pressure at the gas cooler inlet to control the blowdown gas flow rate of the louver-type dust collector.

The blowdown gas flow rate control device of the louver type dust collector in the exhaust gas treatment apparatus of the present invention for carrying out this control method is provided with a louver type dust collector in the exhaust gas duct connected to the gas cooler, and downstream thereof. In an exhaust gas treatment device with a secondary dust collector and a main exhaust fan downstream of it, a dust hopper was provided at the lower end of the dust removal pipe of the louver type dust collector, and a blowdown pipe was connected in the middle. , The blowdown pipe is provided with a blowdown system dust collector in the middle, a flow rate control valve is installed downstream thereof, the tip of the blowdown pipe is connected to the exhaust gas duct in front of the main exhauster, and the inlet of the gas cooler is connected. A pressure detector for detecting the gas pressure is provided in the operation unit connected to the variable throat opening setting device of the secondary dust collector and the flow setting valve opening setting device of the blowdown pipe. Electrically connected And it features.

A blowdown gas flow rate control method for a louver-type dust collector in an exhaust gas treatment apparatus, which is another aspect of the present invention, provides a louver-type dust collector in an exhaust gas duct connected to a gas cooler,
In an exhaust gas treatment device with a secondary dust collector downstream of it and a main air exhauster downstream of it, the flow rate of exhaust gas upstream and downstream of the exhaust gas duct to which the blowdown pipe of the louver type dust collector is connected. A pressure detector provided at the gas cooler inlet is connected to the control mechanism, and the exhaust gas flow rate control mechanism is operated according to the change in the gas pressure at the gas cooler inlet to control the blowdown gas flow rate of the louver type dust collector. It is characterized by controlling.

The blowdown gas flow rate control device of the louver type dust collector in the exhaust gas treatment apparatus of the present invention for carrying out this control method is provided with a louver type dust collector in the exhaust gas duct connected to the gas cooler, and downstream thereof. In an exhaust gas treatment device with a secondary dust collector and a main exhaust fan downstream of it, a dust hopper was provided at the lower end of the dust removal pipe of the louver type dust collector, and a blowdown pipe was connected in the middle. , Connect the tip of the blowdown pipe to the exhaust gas duct before the secondary dust collector,
A damper is provided in the exhaust gas duct upstream of the connecting portion, and a pressure detector for detecting the gas pressure is provided at the gas cooler inlet,
The pressure detector is electrically connected to a variable throat opening setting device of the secondary dust collector and a calculator connected to the damper opening setting device.

[Action]

According to the present invention, the gas pressure at the inlet of the gas cooler is detected, and the blowdown gas flow rate of the louver-type dust collector becomes constant either directly or indirectly by the comparison calculation of the detected gas pressure and the reference pressure. Controlled.

〔Example〕

An embodiment of a blowdown gas flow rate control device for carrying out a blowdown gas flow rate control method for a louver type dust collector in an exhaust gas treatment apparatus which is one of the present invention will be described with reference to FIG. Reference numeral 10 denotes a converter in which molten iron supplied from a blast furnace is charged together with a refining material such as scrap, and refined with oxygen blown from a lance and / or a bottom nozzle (not shown) to produce steel. Reference numeral 11 is a gas cooler that guides a large amount of high-temperature, high-dust-containing gas generated from the converter 10 during refining and cools it to an appropriate temperature. 12 is an exhaust gas duct connected to the gas cooler 11,
13 is a louver type dust collector provided in the exhaust gas duct, 14 is a secondary dust collector such as a wet venturi provided downstream of the louver type dust collector 13, and 15 is a downstream side of the secondary dust collector 14. The main exhaust fan 16 is provided at the downstream side of the main exhaust fan 15, and the exhaust gas duct 12 is provided with a passage 18 to a gas exhaust stack 17 and a gas holder.
It is a three-way switching valve provided at the branch portion that branches into the passage 20 to the passage 19.

A dust hopper 22 is provided at the lower end of the duct extraction pipe 21 of the louver type dust collector 13, and a blowdown pipe 23 is connected in the middle of the dust extraction pipe 21 at an angle smaller than an angle orthogonal to the flow direction of the dust extraction pipe 21. Has been done. Blowdown tube 23
A blowdown dust collector 24 using a ceramics filter (may be a cyclone dust collector, a bag filter, a wet dust collector, etc.) is provided in the middle of the blowdown dust collector. A flow rate control valve 25 is provided in the middle of the blowdown pipe 23 ′ downstream of the dust container 24, and the tip of the blowdown pipe 23 ′ is located upstream of the throat portion 26 of the exhaust gas duct 12 in front of the main exhaust fan 15 and is in the upper half. It is connected to the circumferential position at an angle smaller than 90 degrees with respect to the gas flow direction. At the inlet of the gas cooler 11, a pressure detector 27 for detecting the gas pressure at the furnace opening of the converter 10 is provided, and the pressure detector 27 is the opening degree of the variable throat 14a of the secondary dust collector 14. Opening setter 29 of flow control valve 25 in the middle of setter 28 and blowdown pipe 23 '
Is electrically connected to the arithmetic unit 30 connected to the.

A blowdown gas flow rate control method of the present invention using the blowdown gas flow rate control device configured as described above will be described. In FIG. 1, the molten iron supplied from the blast furnace and refining materials such as scrap are inserted into the converter 10 together, and refined into oxygen by blowing oxygen from a lance (not shown) and / or a bottom nozzle to form steel. .

A large amount of high-temperature, high-dust-containing gas generated at this time is introduced into the gas cooler 11, cooled to an appropriate temperature, and then introduced into the louver-type dust collector 13 of the exhaust gas duct 12, and the louver-type dust collector is collected. The dust container 13 separates coarse particles. The low dust-containing gas from which coarse-grained dust is separated is guided to the secondary dust collector 14 to remove dust, and is sucked by the main exhaust fan 15 as clean gas, and the CO concentration in the exhaust gas is changed by switching the three-way switching valve 16. When the CO concentration is high, it is sent to the gas holder 19 as a valuable gas through the passage 20 and stored, and when the CO concentration is low, it is sent to the gas diffusion stack 17 through the passage 18 and burned at the top to the atmosphere. Be dissipated in.

On the other hand, the dust collected by the louver-type dust collector 13 is stored in the dust hopper 22 through the dust removal pipe 21 and discharged from the lower discharge valve 22a. The blowdown gas and the scattered dust enter the blowdown system dust collector 24 through the blowdown pipe 23, and the dust is collected. After the dust is removed, the clean blowdown gas is blowdown pipe 23 '.
Through the exhaust gas duct 12 to the upstream of the throat portion 26 of the exhaust gas duct 12, and joins with the clean gas that has been dedusted by the secondary dust collector 14.

The amount of gas generated from the converter 10 depends on the blowing time, blowing conditions,
It varies from moment to moment depending on the reaction status in the furnace. The gas pressure at the furnace opening accompanying this is detected by the pressure detector 27 at the inlet of the gas cooler 11, and the detected pressure is sent to the calculator 30 and compared with the reference pressure (usually atmospheric pressure), and its deviation An opening / closing signal is sent to the opening setting device 28 of the variable throat 14a of the secondary dust collector 14 according to the value, and the opening of the variable throat 14a is adjusted. As a result, the amount of gas passing through the exhaust gas treatment device is constantly changing,
Along with this, the inlet pressure of the main air exhauster 15 also constantly fluctuates, the blowdown gas amount of the louver type dust collector also constantly fluctuates, and it becomes difficult to maintain stable efficiency of the louver type dust collector 13. However, in the present invention, as described above, the open / close signal is sent from the calculator 30 to the opening setting device 28 of the variable throat 14a of the secondary dust collector 14 and at the same time the flow control valve 25 is opened in the middle of the blowdown pipe 23 '. Since it is also sent to the degree setter 29, the opening degree of the flow rate control valve 25 is adjusted. Therefore, the blowdown gas flow rate is always sucked at a constant ratio with respect to the amount of gas passing through the louver-type dust collector 13, as shown in FIG. It is possible to keep the collection efficiency stable.

Next, an embodiment of a blowdown gas flow rate control device for carrying out a blowdown gas flow rate control method for a louver type dust collector in an exhaust gas treatment device which is another one of the present invention will be described with reference to FIG. . In the figure, the same reference numerals as those in FIG. Louvered dust collector 13
A dust hopper 22 is provided at the lower end of the dust removing pipe 21, and a blowdown pipe 23 is connected to the dust removing pipe 21 at an angle smaller than an angle orthogonal to the flow direction of the dust removing pipe 21. The tip of the blowdown tube 23 is a secondary dust collector.
It is connected to the exhaust gas duct 12 before 14. A damper 31 is provided in the exhaust gas duct 12 upstream of the connection portion of the blowdown pipe 23, an opening setting device 32 is connected to the damper 31, and the opening setting device 32 is electrically connected to a computing device 30. Has been done. At the inlet of the gas cooler 11, a pressure detector 27 for detecting the gas pressure at the furnace opening of the converter 10 is provided.
Is electrically connected to the arithmetic unit 30. The calculator 30 includes an opening setting device 28 for the variable throat 14a of the secondary dust collector 14.
Is also electrically connected.

A blowdown gas flow rate control method of the present invention using the blowdown gas flow rate control device configured as described above will be described. A large amount of high-temperature, high-dust-containing gas generated from the converter 10 is introduced into the gas cooler 11 and, after being cooled at an appropriate temperature, is introduced into the louver-type dust collector 13 of the exhaust gas duct 12 and the louver. The coarse dust is separated by the mold dust collector 13. The separated coarse particles are stored in the dust hopper 22 through the dust extraction pipe 21 and discharged from the lower discharge valve 22a. The blowdown gas and the scattered dust enter the exhaust gas duct 12 upstream of the secondary dust collector 14 through the blowdown pipe 23, and join with the low dust-containing exhaust gas that has passed through the louver type dust collector 13. It enters the secondary dust collector 14 to remove dust. Dust-removed clean gas is sucked by the main exhauster 15, and when the CO concentration in the exhaust gas is high by switching the three-way switching valve 16, it is sent as a valuable gas through the passage 20 to the gas holder 19 and stored, When the CO concentration is low, the gas is sent to the gas diffusion stack 17 through the passage 18, and is burned at the top and released to the atmosphere.

The amount of gas generated from the converter 10 depends on the blowing time, blowing conditions,
It varies from moment to moment depending on the reaction status in the furnace. The gas pressure at the furnace opening accompanying this is detected by the pressure detector 27 at the inlet of the gas cooler 11, and the detected pressure is sent to the calculator 30 and compared with the reference pressure (normal body pressure), and its deviation An opening / closing signal is sent to the opening setting device 28 of the variable throat 14a of the secondary dust collector 14 according to the value, and the opening of the variable throat 14a is adjusted. As a result, the amount of gas passing through the exhaust gas duct 12 constantly changes,
Along with this, the inlet pressure of the main air exhauster 15 also constantly fluctuates, the blowdown gas amount of the louver type dust collector 13 also constantly fluctuates, and it is difficult to maintain stable efficiency of the louver type dust collector 13. However, in the present invention, as described above, an opening / closing signal is sent from the calculator 30 to the opening setting device 28 of the variable throat 14a of the secondary dust collector 14, and at the same time, to the opening setting device 32 of the damper 31 of the exhaust gas duct 12. Also, since the opening / closing signal is sent, the opening degree of the damper 31 is adjusted. Therefore, the amount of gas flowing through the louver type dust collector 13 is adjusted, and accordingly, the blowdown gas flow rate is always sucked at a constant ratio with respect to the amount of gas passing through the louver type dust collector 13. Louvered dust collector 13
It is possible to stably maintain the dust collection efficiency of.

〔The invention's effect〕

As can be seen from the above description, according to the present invention, the gas pressure at the gas cooler inlet is detected, and the blowdown gas of the louver type dust collector is directly or indirectly calculated by comparing the detected gas pressure with the reference pressure. The flow rate is controlled to be constant,
There is an effect that the dust collection efficiency of the louver type dust collector is stably maintained at a high level.

[Brief description of drawings]

FIG. 1 is a schematic view showing an apparatus for carrying out a blowdown gas flow rate control method for a louver type dust collector in an exhaust gas treatment apparatus of the present invention, and FIG. 2 is an amount of gas passing through an exhaust gas duct side and a blow. FIG. 3 is a schematic diagram showing an apparatus for carrying out another blowdown gas flow rate control method of the present invention, and FIG. 4 is provided with a louver type dust collector. It is the schematic which shows the conventional exhaust gas processing apparatus. 11 …… Cooler, 12 …… Exhaust gas duct 13 …… Louver type dust collector, 14 …… Secondary dust collector 14a …… Variable throat, 15 …… Main exhauster 21 …… Dust vent pipe 22 …… Dust Hopper 23,23 ′ …… Blowdown pipe 24 …… Blowdown dust collector 25 …… Flow control valve, 27 …… Pressure sensor 28 …… Variable throat opening setting device 29 …… Opening flow control valve Degree setting device 30 …… Calculator, 31 …… Damper 32 …… Damper opening setting device

Claims (4)

[Claims] 1. An exhaust gas treatment apparatus comprising a louver type dust collector provided in an exhaust gas duct connected to a gas cooler, a secondary dust collector provided downstream thereof, and a main air exhauster provided downstream thereof. Connect the pressure detector installed at the gas cooler inlet to the flow rate control mechanism installed in the blowdown system of the dust collector.
A louver type dust collector in an exhaust gas treatment apparatus, characterized in that the flow rate control mechanism is operated according to a change in gas pressure at the gas cooler inlet to control the blowdown gas flow rate of the louver type dust collector. Blowdown gas flow rate control method. 2. A louver in an exhaust gas treatment device, wherein a louver type dust collector is provided in an exhaust gas duct connected to a gas cooler, a secondary dust collector is provided downstream thereof, and a main exhauster is provided further downstream thereof. Type dust collector has a dust hopper at the lower end of the dust removal pipe, a blowdown pipe is connected in the middle, and a blowdown system dust collector is provided in the middle of the blowdown pipe, and a flow control valve is installed downstream thereof , The tip of the blowdown pipe is connected to the exhaust gas duct in front of the main exhauster, a pressure detector for detecting the gas pressure is provided at the inlet of the gas cooler, and the pressure detector is connected to the variable throat of the secondary dust collector. Blowdown gas flow rate of louver type dust collector in exhaust gas treatment equipment characterized by being electrically connected to an arithmetic unit connected to the opening degree setter and the opening degree setter of the flow rate control valve of the blowdown pipe Control device. 3. A louver in an exhaust gas treatment device, wherein a louver type dust collector is provided in an exhaust gas duct connected to a gas cooler, a secondary dust collector is provided downstream thereof, and a main air exhauster is provided further downstream thereof. Type dust collector, a pressure detector provided at the gas cooler inlet is connected to the exhaust gas flow rate control mechanism upstream and downstream of the exhaust gas duct connected to the blowdown pipe, and the exhaust gas flow rate control mechanism is connected to the gas cooler inlet gas. A blowdown gas flow rate control method for a louver type dust collector in an exhaust gas treatment device, which is operated according to a change in pressure to control the blowdown gas flow rate of the louver type dust collector. 4. An exhaust gas treatment device comprising a louver type dust collector provided in an exhaust gas duct connected to a gas cooler, a secondary dust collector provided downstream thereof, and a main air exhauster provided downstream thereof. A dust hopper is provided at the lower end of the dust extraction pipe of the mold type dust collector, a blowdown pipe is connected in the middle, and the tip of the blowdown pipe is connected to the exhaust gas duct in front of the secondary dust collector. A damper is provided upstream in the exhaust gas duct, a pressure detector for detecting gas pressure is provided at the gas cooler inlet, and the pressure detector is used to set the opening of the variable throat of the secondary dust collector and the opening of the damper. A blowdown gas flow controller for a louver-type dust collector in an exhaust gas treatment device, which is electrically connected to a calculator connected to the container.