JPS6333886B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a blast furnace top gas cleaning device.

The top gas of the blast furnace contains dust of approximately 10 g/Nm ³ , and the dust also contains particles with a maximum particle size of several millimeters. Conventionally, such dust-containing gases are removed to reduce the dust content to, for example, about 5 to 10 mg/Nm ³ . As a method, the blast furnace top gas is first introduced into a coarse dust collector, where coarse dust is removed, and then the gas is further led into a dust collector, where the dust in the gas is collected and purified. It is stored as gas and used again as blast furnace gas.

As the dust collector in the above-mentioned conventional blast furnace top gas cleaning method, a wet dust collection method and a dry dust collection method have been adopted.

In the wet dust collection method, dust is removed by bringing gas cleaning water into contact with the dust-containing gas, but as the water evaporates, the amount of gas increases, and as a result, downstream equipment becomes larger. Since the recovered gas contains moisture, the calorific value per unit capacity is small, and since the gas is cooled to about 60°C, there are problems in that the sensible heat of the blast furnace top gas cannot be recovered.

On the other hand, in the dry dust collection method, the dust collection section is made up of a layer of abrasion-resistant filter material such as sand, and when the dust-containing gas passes through this dry dust collection section, the dust in the gas is collected. This is what we are trying to remove. In this method,
In recent years, dry dust collection methods have been adopted in place of wet dust collection methods because they do not have the problems of the wet methods mentioned above, and moreover, they can remove dust with high performance and low pressure loss, and recover clean gas at high temperature and pressure. It has reached the point where

In the conventional dry dust collection method, as mentioned above, the drop in gas temperature, calorific value, and pressure is small.
In the case of gas (approximately 3 atmospheres), the large amount of energy it possesses can be used effectively, so it is stored after being led to an energy recovery section.

An example of a conventional dry dust collection method is one in which abrasion-resistant filter materials such as sand or gravel are movably filled in layers between vertically arranged wire meshes or perforated metal plates, either continuously or intermittently. There is a device in which dust is collected by allowing gas to pass through the filled filter material.

However, in this method, since the filter material in the packed bed is movable, the dust collected in the dust collection section moves from the top to the bottom of the filter material packed bed, not only downward but also to the downstream side of the gas. Since it moves, the collection efficiency will decrease. In order to increase this collection efficiency, it is necessary to have multiple packed layers. A means for moving and circulating the filter media is also required.

In addition, conventionally, a packed bed of abrasion-resistant filter material such as sand is formed in a horizontal state inside the cylindrical body, and dust is collected when gas passes through this fixed packed bed.
In addition, air is blown upward from below the packed bed from an air pipe led from outside to the bottom of the packed bed, and the dust collected in the packed bed is made to float by the head wind that blows up the packed bed. There were also some configurations.

However, with this method, the suspended dust is discharged by settling downward from the spaces between the filled layers arranged in the circumferential direction, so the suspended dust cannot be discharged quickly. At the same time, a blower pipe is required to introduce air from the outside to fluidize the packed bed, and the presence of spaces between the packed beds makes it impossible to continuously collect dust-containing gas.

The present invention aims to eliminate the above-mentioned problems in the dry dust collection method and to continuously collect and remove dust, and includes a coarse dust collector installed in the upper part of a container that guides gas from the upper part to the lower part. A packed bed filled with a filter material is provided in a horizontal state on the downstream side of the coarse dust collector, and gas is sucked above the packed bed in a direction opposite to the gas flow to partially close the packed bed. A fluidizing cleaning hood is positioned so that the cleaning hood and the packed bed move relative to each other, and a heat storage device is further provided on the downstream side of the coarse dust collector for equalizing the gas temperature. It is characterized by the fact that it is equipped with

Embodiments of the present invention will be described below with reference to the drawings.

FIG. 1 shows an example of the present invention, in which a large diameter dust collecting container 1 having a gas inlet 2 in the upper part and a clean gas outlet 3 in the lower part has a coarse dust collector 4 in the center thereof and a coarse dust collector 4 in the top part. a coarse grain duct 5 having a hopper of
Further, on the downstream side of the coarse dust collector 4 in the container 1, a wire mesh,
Filled layers 7 and 8 are arranged in upper and lower layers to form a filter dust collection system by using a metal porous plate as the bottom plate and filling with abrasion-resistant filter material 6 made of grains such as sand and having a substantially uniform particle size. Each filling layer 7, 8 is partitioned into a plurality of parts in the radial direction by a partition plate 9, and also partitioned into many parts in the circumferential direction by a large number of partition plates 10 extending radially. divided into small rooms,
The gas on the upstream side must pass through the packed beds 7 and 8.

A rotary cylinder 11 is arranged concentrically on the outside of the coarse grain duct 5, and the coarse grain duct 5 is made airtight by a gas seal 12. The rotary cylinder 11 is made airtight through the seal 14, and the rotary cylinder 11 can be rotated while maintaining airtightness. Rotating cylinder 1
For a rotation of 1, the upper box girder 1
The rotating tube 1 is rotated by the guide roller 15 attached to 3.
A rail/gear 16 that guides the upper part of the container 1 and is attached to the outer periphery of the lower end of the rotating tube 11 is received by a guide roller 17 attached to the container 1. 11
can be rotated. This rotating cylinder 1
1, fine particle ducts 20 and 21 corresponding to the upper and lower two stages of packed layers 7 and 8 are fixed at multiple locations on the circumference,
Further, cleaning hoods 22, 23 are arranged on the upstream side of each packed bed 7, 8, that is, on the upper surface of the packed bed, and the number and size of cleaning hoods 22, 23 correspond to the radial compartments and compartment sizes. Each cleaning hood (first
22 (corresponding to the radially outer packed layer is shown in the figure) are respectively connected to the fine particle duct 20 fixed to the upper stage, and similarly the lower packed bed 8
(the one corresponding to the radially inner packed bed is shown in Figure 1)
23 is also a fine particle duct 2 fixed to the lower stage of the rotating cylinder 11.
1, so that the upper and lower cleaning hoods 22, 23 are rotated by the rotation of the rotary cylinder 11.

In this embodiment, the cleaning hoods 22 and 23 have a size that almost matches the size of the packed bed portion of each partitioned small chamber in the circumferential direction, and are located on the front and rear sides in the direction of rotation as shown in FIG. It has a skirt 24 as shown in FIG.
Further, each of the fine particle ducts 20 and 21 is connected to various dust collectors outside the container 1 through the inside of the rotary cylinder 11, and the insides of the hoods 22 and 23 are made to have a negative pressure by a blower or the like.

Further, on the downstream side of the coarse dust collector 4 and on the upstream side of the upper packed bed 7, a heat storage device 25 for equalizing the gas temperature is arranged, and the heat storage device 25 is connected to the coarse dust collector 4 and the container. 1, so that the temperature of the gas passing through the coarse dust collector 4 is made uniform.

The particle size of the filter medium 6 in the packed beds 7 and 8 is preferably a size that will not be scattered by suction by the cleaning hoods 22 and 23, for example, about 3 mm, but it is suitable for particles contained in the gas. It is natural to change the ratio depending on the size of the dust. 26 is leg, 2
7 is a telescopic tube.

Since the device of the present invention has the above configuration,
Now, the dust-containing gas that has entered this device via the pipes at the top of the blast furnace is transferred to the first
As shown by the arrow in the figure, it flows laterally and moves downstream.
At this time, coarse dust (iron ore, about 200 microns or more) falls into the hopper of the coarse dust collector 4 due to its own weight due to the gas traveling. In this way, after the coarse dust has been collected by the gravity dust collection method, the gas is passed through the packed beds 7 and 8 in order, and the fine dust is collected therein.

That is, the gas that has passed through the coarse dust collector 4 first passes through the upper packed bed 7, where most of the dust is collected and deposited on the packed bed 7. The gas that has passed through the packed bed 7 passes through the lower packed bed 8, and at this time, dust is further collected and deposited on the packed bed 8. The gas that has passed through the lower packed bed 8 is discharged from the gas outlet 3 of the container 1 as clean gas.

The cleaning hoods 22 and 23 on the upstream sides of the packed beds 7 and 8 in each stage are slowly rotating together with the rotary cylinder 11 rotated by the drive device 18, and the cleaning hoods 22 and 23 are arranged on the upstream side of the packed beds 7 and 8 in each stage. Each of the small chambers in the layers 7 and 8 is caused to flow by causing a portion of the gas that has passed through the packed beds 7 and 8 to flow backwards from below to above in each packed bed due to the negative pressure in the hoods 22 and 23. Layered. As a result, the dust deposited on the packed bed 7 is suspended and scattered by the gas flowing back, and is sucked and collected by the cleaning hood 22. Similarly, the dust deposited on the packed bed 8 is removed from the hood 2.
3, it is collected by suction. At this time, the packed layers 7, 8
Since the filter medium 6 has a certain particle size, it is not scattered by the backflow of the gas and is washed into clean particles. In addition, cleaning hood 2
Since the skirts 24 are provided at the cleaning hoods 22 and 23, it is difficult for gas on the upstream side of the packed bed to enter the cleaning hoods 22 and 23.

The gas containing the scattered dust sucked by the cleaning hoods 22 and 23 passes through the fine particle ducts 20 and 21 and is led to a dust collector outside the container 1.

In the above explanation, the relationship between the filled layers 7 and 8 and the corresponding cleaning hoods 22 and 23 is as follows.
8 is fixed and the cleaning hoods 22 and 23 are rotated, but as shown in FIG. 4, the cleaning hoods 22 and 23 may be fixed and the packed beds 7 and 8 are rotated. can. That is, the cleaning hoods 22 and 23 are fixed to the container 1 via the fine particle ducts 20 and 21, respectively, while the filling layers 7 and 8 are
The outer peripheral surface rails 28, 28 are respectively attached, and the inner ends of the box girders 13, 13 are rotatably supported via the gas seals 29 of the coarse grain duct 5, and the required parts are arranged circumferentially on the side wall of the container 1. The rails 28, 28 are placed on several rollers 30, 30, respectively, and the appropriate rollers 30 of each stage of the rollers 30 are connected via a power transmission device 32 to a drive deceleration device 31 that is installed outside the container 1. The portion of the roller 30 that is connected to the
The gas seal plate 33 is used to maintain airtightness. Note that 34 is a coarse dust cutting device.

In this method as well, gas cleaning can be performed in the same way as in the case of FIG.
The accumulated dust is removed by backwashing using a fluidized bed.

Next, in the case of blast furnace top gas, due to the peculiarities of blast furnace operation, gas blow-through inside the furnace and slipping of raw materials may occur, and the gas temperature may rise abnormally in a very short period of time. Temperatures of about 150℃ to 200℃ can reach 800℃ or higher. Gas with such an abnormally high temperature causes a decrease in dust collection performance and damage to equipment.

In the above-described embodiment of the present invention, if the heat storage device 25 is provided downstream of the coarse precipitator 4 and upstream of the packed bed 7 as shown in the figure, the above-mentioned abnormal temperature rise that rarely occurs for a short period of time can be prevented. It can be absorbed by the heat storage device 25, and the peak temperature in FIG. 5 can be reduced to less than about 300° C. as shown in FIG. As a result, the temperature of the blast furnace top gas on the upstream side of the packed bed 7 is equalized, there is no abnormal temperature, there is no deterioration in the dust collection performance of the packed bed as a dust collector, and there is no damage to the downstream equipment. It disappears.

If the above-mentioned abnormal temperature rise is for a short period of time as described above, it can be absorbed by the heat storage device 25 as described above, but when the high temperature time becomes long, it cannot be absorbed by the heat storage device 25, and the abnormally high temperature rise is caused in the packed bed 7. It is also possible that gas flows. In such a case, the heat storage device 2
The temperature may be lowered by, for example, sprinkling water on the upper part of the tube.

Although the blast furnace gas purifying device of the present invention has been described above, it is not limited to the illustrated and explained embodiments; for example, the number of stages of the packed bed is arbitrary, and the packed bed is However, if the cleaning hood can partially transform the packed bed into a fluidized bed state and remove the scattered dust, the packed bed may not need to be divided into multiple parts. Of course, various other changes may be made without departing from the spirit of the present invention.

As described above, according to the blast furnace gas purifying device of the present invention, (i) After rough dust collection in one container, the dust is collected in a dry packed bed to produce clean gas, so that high temperature (approximately 100 to 200 degrees Celsius) and high pressure (approximately 1 to 3 atmospheres), it can effectively process large amounts of gas containing dust.

(ii) The coarse dust collector creates an inverted transverse flow and uses gravitational settling to coarsely collect the dust, so it has a simple mechanism and can perform effective coarse dust collection.

(iii) The dust collected and deposited in the packed bed is suspended by the gas flowing back by suction by the cleaning hood, and is removed by suction by the cleaning hood, so there is no need to separately blow in cleaning gas from the outside. There is no need to provide a space for dust to descend in the circumferential direction as in the past, and dust can be collected continuously, resulting in good dust collection efficiency.

(iv) By making the cleaning hood movable, the cleaning hood is small and lightweight, making it easy to move and having a simple mechanism.Also, by making the cleaning hood fixed and the packed bed movable, it is easy to move the cleaning hood to the packed bed. Easy replenishment and replacement of wear-resistant filter media.

(v) By installing a heat storage device downstream of the coarse precipitator, even if an abnormal temperature rise occurs in the gas during blast furnace operation, this abnormal temperature rise can be absorbed by the heat storage device and the temperature can be maintained. , it is possible to prevent deterioration of dust collection performance and damage to equipment.

It can produce excellent effects such as

[Brief explanation of the drawing]

FIG. 1 is a partial explanatory diagram showing an example of the blast furnace gas purifying device of the present invention, FIG. 2 is an enlarged view in the direction of the arrow in FIG. 1, FIG. 3 is an enlarged view in the direction of the arrow in FIG. 1, and FIG. A partial explanatory diagram showing another example of the blast furnace gas purifying device of the present invention, FIG. 5 is a diagram showing the state of abnormal temperature rise of the blast furnace top gas, and FIG. 6 is a diagram showing the state of the temperature of the gas passing through the regenerator. FIG. 1... Dust collection container, 4... Coarse dust collector, 5... Coarse particle duct, 7, 8... Filled bed, 11... Rotating tube, 2
0, 21...Particle duct, 22, 23...Cleaning hood, 25...Regenerator, 28...Rail.

Claims (1)

[Claims] 1. A coarse dust collector is provided at the upper part of a container that guides gas from the upper part to the lower part, and a packed bed filled with a filter material is provided in a horizontal state on the downstream side of the coarse dust collector. ,
A cleaning hood that partially fluidizes the packed bed by suctioning gas in a direction opposite to the gas flow is positioned above the packed bed, so that the cleaning hood and the packed bed move relative to each other. A blast furnace gas cleaning device characterized by the following. 2. A coarse dust collector is provided in the upper part of the container that guides the gas from the upper part to the lower part, and a packed bed filled with a filter material is provided in a horizontal state on the downstream side of the coarse dust collector, and
A cleaning hood is positioned above the packed bed to partially fluidize the packed bed by sucking gas in a direction opposite to the gas flow, and the cleaning hood and the packed bed are moved relative to each other; A gas cleaning device for a blast furnace, further comprising a heat storage device downstream of the coarse precipitator for equalizing gas temperature.