JPS6220252B2 - - Google Patents

Description

Detailed Description of the Invention (Industrial Field of Application) The present invention is intended for emergency use in order to prevent abnormal negative pressure during an emergency shutdown in a closed converter exhaust gas treatment equipment that operates in a sealed or nearly sealed state. The present invention relates to a converter exhaust gas treatment device equipped with an air intake valve.

(Prior art and its problems) The outline of the converter exhaust gas treatment device will be explained with reference to FIG. 1. Pure oxygen is blown into the hot metal poured into the converter 1 through the oxygen injection lance hole 13 for refining. . During this blowing, carbon in the hot metal and lance hole 1
The oxygen blown in from 3 reacts and a large amount of high-temperature CO gas is generated. Gas with low CO concentration at the beginning and end of the blowing is drawn into the hood 3 by the induced blower 7, cooled by the hood 3 and cooler 4, removed by dust removers 5 and 6, and removed from the dispersion tower. 8
It burns at the top and dissipates into the atmosphere. Gas with high CO concentration at the peak of blowing is damper 1.
0 and is recovered as a valuable gas through a water seal valve 11 and a duct 12 to a gas holder (not shown).

Furthermore, if CO gas leaks outside, it is not only extremely dangerous as it will cause CO poisoning, but there is also the risk of rapid combustion when it reacts with the outside air. Therefore, a skirt 2 that can be raised and lowered is provided between the opening of the converter 1 and the hood 3, and the skirt 2 is lowered to close the gap between the opening of the converter 1 and the skirt 2, thereby removing CO gas from the outside. This prevents leakage and outside air from entering into the skirt 2.

In this converter exhaust gas treatment equipment, the converter operation is as follows:
It is carried out in the following three steps. That is, a pig iron receiving process in which hot metal produced in a blast furnace (not shown) is injected into the converter 1, a blowing process in which pure oxygen is blown into the hot metal injected into the converter 1 to refine it, and a It is carried out in three steps: the steel tapping step, in which molten steel is taken out from the converter 1.

Of the three processes mentioned above, the pig iron receiving process and the tapping process are performed by tilting the converter 1, so the skirt 2 is raised, and in the blowing process, the skirt 2 is lowered, and the opening of the converter 1 and the skirt are lowered. The two spaces are closed to prevent CO gas from leaking out and outside air from entering.

However, the furnace mouth of the converter 1 was not necessarily flat due to the accumulation of slag, and it was impossible to make close contact between the skirt 2 and the furnace mouth, so the furnace was closed with a certain amount of clearance. . Therefore, some outside air entered through the gap, and the CO concentration inevitably decreased.

On the other hand, nowadays there is a demand for recovery of gas with a high CO concentration (purity), and the space between the furnace opening of the converter 1 and the skirt 2 has come to be completely sealed or nearly completely sealed. .

In such a completely sealed converter exhaust gas treatment system, if an emergency shutdown occurs, a new technical problem arises.

As a normal emergency stop, oxygen injection is stopped. Therefore, the amount of gas generated from the converter 1 decreases rapidly.

In the conventional open type, outside air is sucked in from the gap between the furnace mouth of the converter 1 and the skirt 2 to compensate for the reduction in the amount of gas generated, and the amount of gas is reduced to match the amount of gas induced by the induced blower 7. was ensured and the pressure inside the exhaust gas treatment equipment was maintained, but in the case of a closed type,
Since there is no outside air suction, or even if there is, it is very small, the pressure inside the exhaust gas treatment equipment instantly becomes negative pressure,
There is a problem in that the exhaust gas treatment device is damaged due to this negative pressure.

For example, if negative pressure instantaneously occurs and outside air intrudes through the sealed portion, or if it breaks and outside air intrudes, a major accident such as an explosion will occur.
(In the high-temperature part of the CO gas, the CO gas and _O2 in the outside air will gradually self-combust and no explosion will occur, but in the low-temperature part after being cooled by a cooler, if there is an ignition source, it will instantly combust. In the case of the conventional open type converter, outside air is sucked in through the gap between the furnace opening of the converter 1 and the skirt 2 to release high-temperature converters.
CO gas reacts with O ₂ in the outside air that is sucked in (combustion of CO gas) to produce CO ₂ gas, and CO gas is generated between the CO gas that was sucked in first and the outside air that is sucked in later. By intervening _two gas layers (this is called an inert gas layer), contact between the cooled CO gas and the subsequently drawn outside air is prevented, and there is no risk of explosion. Since there is no or very little intrusion, there is a problem that a sufficient inert gas layer is not generated and there is a great danger of explosion. In addition, at the beginning and end of blowing, the amount of gas generated from the converter 1 is small and the CO concentration is low, so it is not recovered but is burned at the top through the chimney and dissipated. When there is an emergency stop, the pressure inside the exhaust gas treatment equipment suddenly becomes negative, and the gas flow rate in the chimney decreases, and outside air enters the chimney, causing backfire and combustion or combustion inside the chimney. There is a risk of an explosion.

The instantaneous negative pressure generated by using a closed type system poses a number of unexpected technical problems, which led to the development of a highly safe exhaust gas treatment system that can recover high-purity CO gas. The reality is that there is an urgent need to

(Objective of the Invention) The present invention has been made in view of the above circumstances, and it is an object of the present invention to provide a closed converter exhaust gas treatment device equipped with an emergency air valve to prevent abnormal negative pressure from occurring even during an emergency shutdown. The purpose is to

(Structure of the Invention) The closed type converter exhaust gas treatment device of the present invention includes an air intake port provided in the hood, which is a high temperature part of CO gas, and a valve box with an open top connected to the air intake port. The air intake port is opened by a valve body that seals the upper opening of the valve body and falls guided by a guide rod installed vertically inside the valve box, thereby sucking in outside air and preventing abnormal negative pressure. do.

(Example) An example of the closed converter exhaust gas treatment apparatus of the present invention will be described with reference to the drawings. In FIG. 1, 14 is an emergency air intake valve attached to the hood 3. FIG. 2 is a longitudinal sectional view showing details of this emergency air intake valve 14, and 15 is an air intake port attached to the hood 3. A valve box 16 having an opening 17 at the top is connected to the air intake port 15 . Reference numeral 19 denotes a valve body that seals the opening 17, and is guided by a guide rod 18 so as to fall down.

That is, the valve body 19 is provided with a valve rod 23 , and a locking member 22 provided on the valve rod 23 is locked by an arm 21 driven by a cylinder 20 . In this state, by operating the cylinder 20, the locked state is released and the valve body 19 falls. On the other hand, to seal the opening 17,
The valve body 19 may be brought into close contact with the opening by operating the cylinder 20.

In this embodiment, the valve body 19 is locked by the cylinder 20 via the locking member 22, but the valve body 19 is secured to the opening 1 by a magnet, for example.
The valve body 19 may be in close contact with the valve body 7, and it is sufficient if the valve body 19 is configured to be able to fall.

Next, the operation of this embodiment configured as described above will be explained.

For example, in the event of an emergency situation where the induced fan 7 or other control system stops due to a power outage (the induced fan does not stop abruptly due to inertia), the signal will cause the oxygen injection to stop. At the same time, a command is also given to the cylinder 20 to release the locked state.

In this case, when the oxygen injection is stopped, the pressure becomes somewhat negative, but this negative pressure acts as a suction force on the valve body 19, and the initial speed at which the valve body 19 starts to fall (its own weight) after the lock is released is reduced. This shortens the time from release of the lock to the start of falling, and the opening 17 is opened instantly to suck in outside air.

The outside air sucked in in this way is exposed to high temperature CO2.
The CO gas flows into the gas and is combusted by O ₂ in the air to generate an inert gas layer, and an amount of gas commensurate with the amount of gas sucked by the induced blower 7 is obtained.
Abnormal negative pressure inside the exhaust gas treatment equipment will not occur.

Further, during normal operation, the valve body 19 tightly seals the opening 17, and high purity CO gas is recovered.

(Effects of the Invention) As detailed above, the closed type converter exhaust gas treatment device according to the present invention has an air inlet in the hood, and opens the air inlet by dropping a valve body into the air inlet. Since an air intake valve is installed to prevent oxygen from being blown, even if oxygen injection is stopped in an emergency, the air intake port can be opened quickly and outside air can be sucked in, thereby preventing abnormal negative pressure inside the exhaust gas treatment device. can.

Therefore, there is no risk of equipment damage, explosion due to insufficient inert gas generation, or backfire in the chimney.
It has excellent effects such as being able to create a highly safe closed type converter exhaust gas treatment device and recovering highly purified CO gas.

[Brief explanation of the drawing]

FIG. 1 and FIG. 2 are one embodiment of the present invention,
FIG. 1 is a schematic diagram showing the entire converter exhaust gas treatment device, and FIG. 2 is a longitudinal sectional view of the emergency air intake valve. 3...Hood, 14...Emergency air intake valve, 15...
Air intake port, 16... Valve box, 17... Opening, 18...
Guide rod, 19...valve body.

Claims (1)

[Claims] 1. An air intake provided in the hood of the converter exhaust gas treatment equipment, a valve box connected to the air intake with an open top, and a guide that seals the top opening of the valve box and is vertically installed inside the valve box. Closed type converter exhaust gas treatment equipment equipped with an emergency air intake valve consisting of a valve body that falls along a rod.