JPS5932578Y2 - Converter exhaust gas treatment equipment - Google Patents

Description

[Detailed description of the invention] The present invention relates to a converter exhaust gas treatment device, and to be more specific, the converter exhaust gas is placed in a converter exhaust gas duct and uses the relatively high temperature exhaust gas, which has been cooled in advance, as a heat source. The present invention relates to an improvement in a converter exhaust gas cooling and dust removal device in which a converter input material (scrap iron and other sub-materials f-+) preheating device is provided so as to cross the flow path of the exhaust gas.

There are several types of converter furnaces that have been known and used publicly as steelmaking furnaces, but the one currently in practical use is the exhaust gas (CO2) converter.
A description will be given below using a pure oxygen top-blowing converter (gas) recovery type as an example.

Generally 1,500' to 1,000 m
, high-temperature exhaust gas of about 700°C (contains metal, slag, iron oxide, and other dust ejected from the steel bath in the converter.

) flows in an unburned state through the cooler flue (duct) where most of the outside air is prevented from entering, is first cooled by the cooling device, and after its gas volume is reduced, it is introduced to the dust collector. After being sufficiently cooled and cleaned, it is suctioned and forwarded through a fan.

Finally, by switching the three-way valve, the gas with low CO content at the beginning and end of blowing is released into the atmosphere through the chimney, and the valuable gas with high CO content at the peak of blowing is released into the atmosphere. After that, it is recovered and stored in a raw material or fuel gas holder.

By the way, for exhaust gas whose temperature has dropped to about 1,000℃, the cooling power method using contact (convection) heat exchanger tubes is more effective than radiant (radiation) heat exchanger tubes. Since dust tends to adhere to and accumulate on the surfaces of these convection heat transfer tubes and cause various problems, the upstream portion of the exhaust gas duct near the hood is cooled using radiant heat transfer tubes that form the water-cooled wall.

Heat is recovered and the generated steam is used as a heat source for the factory.

This secondary cooler is further cooled down to about 1,000'C by secondary and tertiary coolers if necessary, and then the exhaust gas is sent to a venturi scrubber, etc., which forms a raindrop atmosphere to remove dust. Cooling and dust removal are performed by direct contact with the jet cooling water.

This is 1. This is because it is technically extremely difficult not only to simply cool exhaust gas of OOO'C or lower, but also to economically recover and effectively utilize its sensible heat, and no suitable means have yet been found.

As mentioned above, in conventional plants of this type, water is generally sprayed for cooling and dust removal once the exhaust gas temperature has dropped to around 1,000°C, which generates a large amount of water vapor and significantly increases the gas volume. This leads to an increase in the capacity of the required dust collector and suction fan, etc., and unnecessary water vapor gets mixed in. This reduces the number of CO emissions from the converter exhaust gas, which is collected in a non-combustible state. However, there were disadvantages and inconveniences such as a significant loss of its utility value.

Therefore, the improvement and development of converter exhaust gas treatment methods and equipment that are free from such disadvantages and inconveniences has become an important issue in recent years. % Kosho No. 49-5).

By the way, the converter waste gas processing power method and apparatus according to this patented invention are based on the following technology:
In particular, in order to cool and dedust the waste gas of oxygen-blown converters, where the waste gas is used for preheating of scrap metal, the waste gas is heated in a cooler (%) via the radiant heating surfaces of the steam generator. ) is pre-cooled and only then is it drawn over the additives present in the preheating chamber (which is vertically or led diagonally from the upper blade to the lower blade) and the preheated scrap metal is removed from the preheating chamber. The waste gas is passed through the scrap iron in the direction of force, and at this time, the waste gas is simultaneously dedusted and pre-purified.

Therefore, according to the present invention, in response to the increase in heat input to the converter due to preheating of the input auxiliary raw materials, in order to balance human heat output, it is possible to reduce the amount of oxygen used, and to reduce the amount of iron and steel used as material for removal. In addition to the benefits of increasing the amount of steel produced by increasing the amount of addition of
Theoretically, it can be naturally expected that the rate of increase in gas amount due to generated steam in the scrubber will be inhibited, and as a result, effects and benefits such as the downsizing of equipment after the wet dust remover will be obtained.

However, since the converter exhaust gas contains a large amount of dust, as disclosed in the present invention, the rear blade of the radiant heating surface of the steam generator is provided with a structure that is connected vertically or diagonally from above to below. If the converter exhaust gas was allowed to pass through while the scrap iron and other additives remained in the preheating chamber 5, which was placed in the
The gaps between these additives become clogged with the above-mentioned dust,
Not only will this result in an increase in gas loss, but it may also significantly impede the flow of exhaust gas, making it difficult to carry out normal smelting operations.

The present invention aims to solve and eliminate various practical drawbacks or disadvantages that are still recognized in the patented invention, and to provide a converter exhaust gas treatment device that is even more economical and highly efficient. It is.

Next, embodiments of the present invention will be described based on the drawings.

First, in FIG. 1 showing a vertical cross-sectional side view of a main part of one embodiment, and FIG. 2 showing a plane in the direction of arrows of a cross section taken along the line ■-■ in FIG. 1, 1 forms a flow path for converter exhaust gas. The duct 2 is a cooling water pipe (or evaporation pipe) for absorbing and cooling the radiant heat of the high-temperature exhaust gas of the converter, and 3 is the converter input material according to the present invention (
auxiliary material f#+) preheating device, and a hood for intake of converter exhaust gas (not shown).

) at a location not far from the exhaust gas dust collector (not shown).

), etc., in the middle of the duct 1.

A cooling water pipe 2a is attached to the upper outer surface of a packet-shaped cylinder 4 in the preheating device 3, and an exhaust gas flow hole 5 is bored in the lower blade peripheral wall of the cylinder 4.

Reference numeral 6 denotes an exhaust gas header that communicates with the cylindrical body 4 through these exhaust gas distribution holes 5 and that hermetically surrounds the outer surface of the cylindrical body 4;
The other end (the left end in FIGS. 1 and 2) is provided with an opening 6a that connects to the duct 1a on the downstream side.

Note that 5a is a shielding cover provided inside the cylindrical body 4 to allow exhaust gas to pass through but to prevent the auxiliary raw material 12 from leaking into the exhaust gas header 6.

Reference numeral 7 denotes a closed chute connected to the lower blade of the auxiliary raw material outlet 4a at the bottom of the cylinder 4, and the lower end of the auxiliary raw material outlet 4a and the closed chute 7 are each equipped with, for example, a fluid container cylinder or a motor. An auxiliary raw material discharge door 8a and an airtight door 9a are provided, which are opened and closed by door opening/closing devices 8 and 9 comprising arm members.

There is an auxiliary raw material input port 4f on the wall of the duct 1 directly above the force cylinder 4.
A cylindrical body 10 is provided to protrude upward, and an airtight door 11a for introducing auxiliary raw materials is opened and closed by a door opening/closing device 11 consisting of a fluid container cylinder and an L-shaped arm member at its upper end opening. It is provided.

13 and 14 are, for example, water-sealing type gas sealing devices provided between the lower end opening of the closed chute 7 and the airtight door 9a, and between the upper end opening of the cylindrical body 10 and the airtight door 11a, respectively; Reference numerals 15 and 16 are belt conveyors and other appropriate transfer devices for supplying and discharging auxiliary materials, respectively.

Next, the operation of the auxiliary raw material preheating device according to an embodiment of the present invention configured as described above will be explained.

In refining using an oxygen top-blowing converter, as auxiliary raw materials, limestone, scale, fluorite, etc. are charged into the converter before oxygen blowing, and iron ore and limestone are charged into the converter during blowing.

These auxiliary raw materials are introduced into and taken out from the preheating device 3 during periods of rest before and after blowing, when no exhaust gas is generated.

When the blowing is completed, the preheated auxiliary raw material 12 in the cylinder 4 is transferred to a roll provided at the bottom of the cylinder 4.

Through the rotation of the feeders 19, 19, the lower bunker 4d
After being dropped into the interior, the belt conveyor 16 for carrying out the auxiliary materials passes through the auxiliary material discharge door 8a and the airtight door 9a, which are opened by the operation of the door opening/closing device 8.9.
is discharged to the top.

This preheated auxiliary raw material is stored in a heat retention bunker (not shown) until it is supplied to the converter.

). Next, after these doors 8a and 9a are both closed, the airtight auxiliary raw material input door lla is opened by the door opening/closing device 11, and the auxiliary raw material conveyed by the auxiliary raw material supply belt/conhair 15 is transferred to the preheating device 3. will be put into the

When the airtight door 11a is closed and blowing is started again, the high temperature exhaust gas generated in the oxygen top blowing converter is removed from the hood (not shown).

) and flows in the duct 1 as shown by the arrow 17.

Meanwhile, the exhaust gas is passed through the cooling water pipe 2 forming a water-cooled wall.
The auxiliary raw material reaches the auxiliary raw material preheating device 3 while being cooled to about 1,000'C.

Then, it flows from the upper blade of the cylinder 4 to the space between the auxiliary raw materials 12, and after performing heat exchange through direct contact, flows out into the exhaust gas header 6 through the gap of the cover 5a and the exhaust gas distribution hole 5, and flows into the exhaust gas header 6 through the opening 6a. and flows down the duct 1a as shown by the arrow 18.

When this blowing ends in about 15 to 25 minutes and the generation of exhaust gas stops, the preheating of the auxiliary raw material is also completed, so the preheated auxiliary raw material is discharged in the same manner as described above.

In FIG. 3 showing the main part of another embodiment, the auxiliary raw material preheating device 3 installed between the ducts 1 and 1a is connected to a water cooling looper 4b on the upstream side, a punching metal 4c on the downstream side, and a bottom part. The space is surrounded by the provided roll feeder 19, 19, and an upper bunker 108 having an auxiliary raw material input port 4g and a lower bunker 4d having an auxiliary raw material outlet 4e are connected directly above and below this enclosed space. and protrude from the upper and lower surfaces of the ducts N and la, respectively.

In the figure, 7a is a closed chute connected to the lower blade of the lower bunker 4d, and 8b is an auxiliary raw material discharge door.

Also in this embodiment, as in the explanation with reference to FIG. 1, before the start of blowing, the auxiliary raw material discharge door 8b is closed.

Close the airtight door 9b and remove the roll feeder 19.1.
9 is also stopped, open the airtight door 11b for introducing auxiliary raw materials.
The airtight door 11b is completely closed after the auxiliary raw material 12 to be preheated is introduced until it reaches an appropriate height inside the upper bunker 10a.

The high-temperature exhaust gas from the converter is cooled to about 1.000° C. in the duct 1 and then reaches the population side of the auxiliary material preheating device 3 as shown by an arrow 17.

The exhaust gas that has passed between the auxiliary raw materials 12 filled inside the water-cooled looper 4b passes through the pores of the punched metal 4c, and then passes through the duct Ha.
The liquid is forcibly drawn inward and flows downstream as shown by arrow 18.

In this case as well, as in the first embodiment described in FIGS. 1 and 2, the auxiliary raw material is finally
The duct is heated to about °C, and the duct in the exhaust gas adheres to the auxiliary raw materials and removes dust.

As the gap between the auxiliary materials in contact with the converter exhaust gas decreases, the force loss increases, so if necessary, as in the case in FIG. is dropped into the lower bunker 4d, and the auxiliary raw material in the upper bunker 10a is replenished into the preheating device.

The work of taking out the preheated auxiliary raw material and adding the auxiliary raw material that should be preheated for the next blowing is the same as in the case of Fig. 1.
This is done by opening and closing the auxiliary raw material discharge door 8b and the airtight doors 9b and 11b, and for example, belt conveyors 15 and 16 are used for supplying the auxiliary raw material and transporting it to the heat-retaining bunker for storage, respectively.

Note that the present invention is not limited to the two embodiments described above, but can be applied to, for example, an opening/closing device for each door.

Various known types can be adopted as appropriate for the auxiliary raw material transfer device, etc., and various design changes can be made within the scope of the invention, including the shape and configuration of the preheating device main body. Not even.

When the auxiliary raw material preheating device according to the present invention is incorporated into a converter exhaust gas treatment device, there will be some differences depending on the capacity of the converter, the length of one blowing time, the type of auxiliary raw material, etc. The results were confirmed.

That is, for example, if the auxiliary material to be preheated is limestone, 1
Taking a 50T converter as an example, the required amount of limestone input is approximately 7.
5T/CH・, and when this is brought into contact with converter exhaust gas at around 1,000°C for about 15 to 30 minutes, the temperature is 350° to 4
Preheated to 00°C, the temperature of the exhaust gas is approximately 850°C
At the same time, the dust content in the exhaust gas decreased to 15
It decreased significantly from 0 g/Nm' to about 30 g/N-.

As is clear from the above explanation, according to the present invention, it is possible to effectively utilize the sensible heat of the converter exhaust gas, which was conventionally thrown away without being recovered.
The auxiliary raw materials that have been preheated to around 0°C are put into the converter, so
The amount of heat input to the converter can be increased.

In order to balance this excess heat input, the amount of iron ore input as the fourth material is increased, so the amount of steel extracted from the converter can be naturally increased.

Furthermore, since the dust in the exhaust gas adheres to the auxiliary raw materials and is removed, although this dust circulates between the preheating device and the converter, the dust content of the exhaust gas that has passed through the preheating device 3 is As mentioned above, as the temperature of the exhaust gas decreases and its volume also decreases,
The equipment after the next dust collector becomes more compact, which has a remarkable effect on improving productivity and profitability.

[Brief explanation of the drawing]

The drawings show an embodiment of the present invention, and FIG.
FIG. 3 is a vertical sectional view showing the main parts of another embodiment. 1.1a...Duct, 2,2a...Cooling water pipe, 3...Sub-material preheating device, 4...
・Cylinder body, 4a, 4e...auxiliary raw material outlet, 4ft
4g...Auxiliary raw material input port, 9a, 9b, 11a,
11b... Airtight door, 12... Sub-raw material, 17, 18... Converter exhaust gas.

Claims (1)

[Scope of utility model registration request] An auxiliary raw material inlet and an auxiliary raw material outlet with airtight doors are opened in the upper and lower blades, respectively, and the storage cylinder for the auxiliary raw material supplied from these input ports is placed in the converter exhaust gas duct to prevent the flow of the exhaust gas. The auxiliary raw material placed in the cylinder is preheated by the high-temperature exhaust gas that has been cooled to about 1,000'C in advance through a water-cooled wall serving as a radiant heat transfer surface, and the exhaust gas is In a converter exhaust gas processing device designed to remove dust, an appropriate supply means such as a roll or a feeder is provided at the bottom of the auxiliary raw material storage cylinder;
A transport means is provided to allow the lower part of the auxiliary raw material to fall into the lower bunker and to transport the preheated auxiliary raw material taken out from the auxiliary raw material outlet to the heat retention bunker for storage. Characteristic converter exhaust gas treatment equipment.