JPH0550326B2 - - Google Patents

Description

[Detailed Description of the Invention] <Object of the Invention> Industrial Application Field The present invention relates to a dust collection method using a plurality of dust collection systems, and more specifically, a local dust collection system that collects dust locally;
When collecting dust using the building dust collection system that collects dust throughout the building, the suction air volume of the dust collector fans of both dust collection systems can be appropriately controlled to reduce frictional work in the dust collection duct. The present invention also relates to a method that can reduce the work of pushing into a bag filter, etc., and reduce the power consumption of a dust collector fan.

Conventional technology Conventionally, when collecting dust from a single dust-generating location, a local dust collection system that collects dust locally and a building dust collection system that collects dust throughout the building etc. have been used. A dust system is used.

In this system, the local dust collection system is constantly operated,
The building dust collection system is operated only when the dust collection air volume exceeds the suction capacity of the local dust collection system.

That is, FIG. 2 shows a dust collection system for a blast furnace building, where 1 is the blast furnace building, 9 and 10 are dust collector fans for the building dust collection system, and dust collector fans for the local dust collection system. In the blast furnace building 1, a so-called building dust collection system dust collection hood 2 is installed at the top of the building 1 in order to collect dust from the entire building, while a local dust collection system is installed at each location where dust is generated. A dust collection hood 3 (consisting of a plurality of hoods) is provided. A dust collection duct 4 is connected to the dust collection hood 2, and this duct 4 is provided with a dust collector fan 9 and a filtration type dust collector 13 consisting of a bag filter group, which constitutes a building system and a dust collection system. Therefore, the dust-containing gas in building 1 is sucked throughout the building.
removed. Similarly, a local dust collection system is composed of a dust collection hood 3, a dust collection duct 4, a dust collection fan 10, and a filtration type dust collector 14 consisting of a group of bag filters.

To explain in more detail, normally in this dust collection system, dust collection hoods 3 are placed locally near the tap hole, in the tap trough, or in the tilting trough where hot metal falls at the end of the tap trough. Dust collection is performed locally when dust is generated or when dust is generated during work, and in this case, the VVVF device 12 operates a dust collection fan according to the amount of dust generated in the local area. It is configured to be able to control 10 rotational speeds. However, if only local dust collection is performed as described above,
For example, it is difficult to collect dust at the end of the pig iron production period when the amount of dust generated increases. Collects the dust that cannot be collected.

For this reason, although conventional dust collection systems have two dust collection systems, such as a local system and a whole building system, the operation rate of the building dust collection system as a whole is poor, especially in blast furnace buildings. For dust collection, the rate is extremely low at around 5-20%.

Problems to be Solved by the Invention The present invention aims to solve the above-mentioned drawbacks. Specifically, for example, in a blast furnace building, when performing dry dust collection on a bag filter using the building and a local dust collection system, To solve the problem that the operation rate of the dust collection system is extremely poor and the power required to operate the dust collection system increases due to the friction work in the dust collection duct and the work of pushing into the bag filter, which increases the operating cost. purpose.

<Structure of the Invention> Means for Solving the Problems and Their Effects In other words, the method of the present invention is such that a dust collector fan and a dust collection duct are connected to a filtration type dust collector consisting of a bag filter, and dust-containing gas is sucked throughout the building. A bypass duct is used to connect the building dust collection system to be removed and the local dust collection system, in which the dust collection fan and dust collection duct are connected to a filtration type dust collector consisting of a bag filter, and where dust is collected locally within the building. When collecting dust by suctioning the dust-containing gas in the building and local dust collection system through this bypass duct,
In the building and local dust collection system, the suction air volume of each dust collector fan and the air volume forced into each filtration type dust collector are always controlled to be approximately equal from the time the tap hole is opened until the tap hole is closed. It is characterized by continuous operation of the building and local dust collector to collect dust.

A more detailed explanation will be given below with reference to FIG.

First, FIG. 1 is a layout diagram of an example of a dust collection system that implements the method of the present invention. When collecting dust in the blast furnace building 1 using this dust collection system, for example, A local dust collection system consisting of a hood 3, a duct 5, a dust collector fan 10, and a filtration type dust collector 14 such as a bag filter is provided for the purpose of collecting dust from the entire casthouse. A building dust collection system consisting of a dust collection fan 9 and a filtration type dust collector 13 such as a bag filter is provided. Therefore, the local dust collection system sucks the dust from the hood 3 into the duct 5, and the dust collector fan 10 pushes it into the filtration type dust collector 14 for dust collection. On the other hand, dust is collected from the entire building by suctioning the dust into the dust generating duct 4 through the hood 2, and pushing the dust into the filtration type dust collector 14 by the dust collecting fan 9 to collect the dust.

In addition, the dust collection ducts 4 and 5 of these two dust collection systems
A bypass duct 6 is provided between them for communication. The bypass duct 6 and the duct 4 are provided with valves 8 and 7, and by switching these valves, for example, local dust collected from the hood 3 and the duct 5 is collected using two dust collector fans 9 and 10. . In other words, even when locally collecting dust in the vicinity of the dust generation point using the local dust collecting hood 3,
In addition to the local dust collection system dust collector 14, dust is also collected using the building dust collection system dust collector 13 that collects dust from the entire building. It will continue to operate until the closure, and both dust collection systems will collect dust. Incidentally, when collecting dust from the entire building, dust can be similarly collected by the dust collectors 13 and 14 of both dust collection systems.

Next, as described above, when the dust collector fans of both dust collection systems are driven to collect dust, the suction air volume of each dust collector fan of each dust collection system and the air volume forced into each filtration type dust collector are made to be approximately the same. to control.

In the conventional example, as already explained with reference to FIG. 2, the dust collection systems are independent from each other, and dust is collected by the dust collectors belonging to each system. For this reason, when dust is collected by both dust collection systems, a difference occurs in the amount of air forced into each dust collector 13, 14. For example, as shown in Fig. 4, the suction air volume of the dust collection fan 9 of the building dust collection system and the
The amount of air forced into the steel is extremely small, almost zero, except in the final stages of tapping.

On the other hand, in the method of the present invention, the suction air volume is controlled via the bypass duct 6 that connects both dust collection systems, so even when there is a significant difference in air volume between the two dust collection systems, the suction air volume is controlled via the bypass duct 6. Flow through the dust collection system, and use multiple dust collector fans to equalize the suction air volume and suck it out. Therefore, the power consumption of the dust collector fan is greatly reduced.

The reason for this is explained as follows.

The power of the dust collector fan is used for frictional work in the duct when transporting dust-containing gas and for pushing the dust into a filtration type dust collector such as a bag filter.

In the present invention, since the suction air volume is divided downstream from the bypass duct 6, the air volume of each duct 4 and 5 is lower than that of the conventional example, and in particular, the frictional work within the duct is proportional to the cube of the air volume. As a result, the amount of work is significantly reduced.

Furthermore, regarding the pushing work into the filtration type dust collector, as the forced air volume decreases, the pressure loss of the bag filter also decreases, so the pushing work decreases.
For example, in FIG. 3, according to the conventional example shown in FIG. 2, the operating point is point A. On the other hand, according to the present invention, the operating point shifts from point A to point B due to the reduction in forced air volume and accompanying pressure loss. The pushing work is now the area of the square BB ₁ OB ₂ rather than the area of the square AA ₁ OA ₂ in the conventional example, and twice this is the pushing work to the bag filters of both dust collection systems. As a result, compared to the conventional case, the amount of work is reduced by an area equivalent to the area of the rectangle ACB ₂ A ₂ , as can be seen by comparing the area of the rectangle AA ₁ OA ₂ and the area twice that of the rectangle BB ₁ OB ₂ .

Example Next, examples will be described.

First, dust collection in the casthouse dust collection is carried out in accordance with the amount of dust-containing gas generated from the opening of the taphole to its closure.
The amount generated fluctuates significantly depending on the timing, such as the early stage of tapping, the final stage, and when the taphole is closed.

That is, the amount of dust increases as the taphole starts to tap, and as the hot metal flows down the gutter, the area where the dust is generated gradually expands. In the middle of tapping, dust generation becomes almost constant, and as the slag ratio increases, the amount of dust generation gradually increases again.

At the end of the tapping stage, when the taphole is closed by the Matsudo gun, dust generation rapidly increases and reaches its peak.

Such a dust generation pattern shows a similar elapsed time for each tap hole, and it is also possible to set a timer for necessary dust collection. Further, dust collection at this time is carried out locally by providing a dust collection hood on the upper surface of the gutter through which the hot metal flows. Therefore, the dust collection hood was removed to prevent the hood near the taphole from interfering with the taphole opening machine and the Matsudo gun when the taphole was opened and closed, respectively, and the dust collection hood was removed. In order to prevent this, the suction air volume is set higher than the normal suction air volume, and the time when the Matsudo gun is closed coincides with the peak of dust generation, so usually the dust collector fans 9 and 10 of the two dust collection systems are closed at the same time. be driven.

To illustrate this operating situation, as shown by the solid line in Fig. 4, in the conventional example, the dust collection air volume is set high at the beginning of tapping, and at the end of tapping, both local dust collection and building dust collection are collected at the maximum load. Dust fans 9 and 10 are in operation.

On the other hand, as shown in Fig. 1, when the air volume is controlled according to the present invention, the suction air volume becomes as shown by the dashed line in Fig. 4, and the air volume of the conventional example is divided into two parts, one for the local dust collection system and one for the building dust collection system. It is distributed to and sucked into the system.

In addition, when controlling according to the present invention as described above,
In FIG. 4, times t ₀ , t ₁ , and t ₂ are set by a timer, and during this period, the valves 7 and 8 of the damper etc.
were closed and fully opened respectively by an electric motor.

In addition, the dust collector fan 9 of the building dust collection system and the dust collector fan 10 of the local dust collection system are controlled in rotation speed by VVVF rotation control devices 11 and 12 based on input signals from a timer.
When each dust collector fan 9, 10 sucks the maximum air volume after _t3 hours, valve 7 is opened, valve 8 is closed, and the two dust collector fans 9, 10 are operated as before. Dust was collected individually by dividing into a building dust collection system and a local dust collection system.

In addition, although the above explanation has mainly been about the dust collection system divided into two dust collection systems for blast furnace cast bed dust collection, it can also be applied to dry dust collection systems using bag filters in addition to blast furnace cast bed dust collection.

<Effects of the Invention> As described above, the present invention provides a system that uses a bypass duct to connect a building dust collection system comprising a filtration type dust collector consisting of a bag filter, a dust collector fan, and a dust collection duct to a local dust collection system having a similar structure. In some dust collection systems and both dust collection systems, the suction air volume of each dust collector fan and the air volume forced into each filtration type dust collector are controlled to be approximately equal to collect dust. Therefore, the frictional work within the ducts in each dust collection system can be greatly reduced, and the work of pushing into the filtration type dust collector can also be greatly reduced.

Taking the scale of dust collection equipment in recent blast furnace casthouses as an example, the average size of the dust collector fan 2 is approximately 1500Kw.
It is normal to have about 100,000 units installed, and from this point of view, it is possible to reduce power consumption by more than 10%, and the effect is quite large. As an application example, the above effects can be expected even if the suction air volumes of two dust collectors are different.

[Brief explanation of the drawing]

Figure 1 is a layout diagram of an example of a dust collection system that implements the method of the present invention, Figure 2 is a layout diagram of a conventional dust collection system, and Figure 3 is a diagram of a filter-type dust collector for the method of the present invention and a conventional example. The graph showing the power, FIG. 4, is a graph comparing the dust collection air volume patterns of the method of the present invention and the conventional example. Symbols 1... Casthouse building, 2... Hood, 3... Hood, 4... Building dust collection system duct, 5... Local dust collection system duct, 6... Bypass duct, 7... Control valve, 8... ... Control valve, 9 ... Dust collector fan of building dust collection system, 10 ... Dust collector fan of local dust collection system, 11
... VVVF rotation speed control device, 12 ... VVVF rotation speed control device, 13 ... Dust collector such as bag filter, 14 ... Dust collector such as bag filter, 15 ...
Control signal circuit.

Claims (1)

[Claims] 1 A building dust collection system in which a dust collector fan and a dust collection duct are connected to a filtration type dust collector consisting of a bag filter, and a dust collection system in which dust-containing gases are sucked and removed throughout the building; A bypass duct connects the duct to a local dust collection system that collects dust locally within the building, and sucks dust-containing gas into the building and the local dust collection system through this bypass duct. When collecting dust using the above-mentioned building and local dust collection system, the suction air volume of each dust collector fan and the forced air volume to each of the above-mentioned filtration type dust collectors are constantly adjusted from the time when the taphole is opened to the time when the taphole is closed. A method for collecting dust using a plurality of dust collecting systems, characterized in that the building and the local dust collector are continuously operated to collect dust by controlling the dust collectors to be approximately equal.