JPS60187611A - Emergency operating method of converter waste gas treating device - Google Patents

Abstract

PURPOSE:To form a substantial tampon gas layer even in a hermetic type titled device by maintaining the opening degree of pressure-regulating dampers at a specified degree, opening an emergencey air intake port then regulating the amt. of the O2 to be blown. CONSTITUTION:A large amt. of gaseous CO is generated from a converter 1 and the gas is induced by an induced draft fan 8 in the stage when the molten iron charged into the converter 1 is decarburized by the pure O2 blown through a lance 4, etc. to manufacture a steel. The opening degrees of dampers 7, 7' are adjusted to prevent leakage of CO and suction of the external air with such converter waste gas treating device. If an emergent state when the fan 8 is stopped by certain cause occurs, the opening degrees of the dampers 7, 7' are maintained constant and an emergency air intake port 13 is opened to suck the external air into the device. The rate of the O2 to be blown through the lance 4, etc. is then adjusted to adjust the amt. of the CO generated from the furnace 1 and an inert gaseous layer is formed by the generated CO and the sucked external air. The stagnating gas is quickly discharged while the part between the initially stangating CO and the external air to be sucked thereafter through the furnace port, etc. is shut off by said layer.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to an emergency operating method for a converter exhaust gas treatment apparatus that operates in a sealed or nearly sealed state.

During the converter operation, a large amount of CO gas is generated from the converter. Recently, there has been a trend toward recovery of the CO gas with higher purity and in as large a quantity as possible.

Along with this, converter exhaust gas treatment equipment is changing from the conventional open type to the closed type.

First, an overview of the converter exhaust gas treatment device will be explained below.

In FIG. 1, hot metal introduced into a converter 1 is decarburized (refined) by pure oxygen injected through an oxygen injection lance 4 or the like to produce steel. At this time, an expanded amount of CO is released from the converter.
Gas is generated.

This CO gas is drawn into the hood 3 by the induced blower 8, cooled by the cooler 12, and then cooled by the dust remover 5.
, 6, and collected in a holder 9. The Co gas recovered in this way is used as fuel or the like.

In this converter exhaust gas treatment device, the skirt 2 and the converter 1
The opening degree of the damper 7 or 1' is adjusted to prevent Co gas from leaking outside from the gap between the furnace opening and the hood 3, and to prevent outside air from being sucked into the hood 3 through this gap. The pressure is adjusted so that the pressure inside is equal to the atmospheric pressure.

That is, if Co gas leaks to the outside, there is a risk of carbon oxide poisoning or explosion, and if a large amount of outside air is sucked into the hood 3 at once, there is a risk of explosion after the amount of dust removed.
7- Pressure regulation within the door 3 is very important.

In addition, 11 in the figure is a switching damper, which burns gas with a low Co gas concentration generated at the beginning of oxygen injection (early stage of blowing) and at the end of blowing when the carbon concentration in the raw material entering the converter decreases. It is provided to discharge air from the chimney.

In this converter exhaust gas treatment equipment, in order to obtain high-purity Co gas, it is necessary to completely prevent outside air from entering the 7-door 3 during blowing. The space between the furnace and the furnace opening is completely sealed or close to this.

In addition, all parts such as the hood penetration part of the oxygen blowing lance 4 and the penetration part of the sub-lance (not shown) are sealed.

In conventional open-type converter exhaust gas treatment equipment, if an emergency situation occurs where the induced blower stops for some reason, if left as is, the CO generated from the converter will be reduced.
Since the gas is no longer drawn into the hood, a large amount of Co gas will blow out from the gap between the skirt and the converter mouth, resulting in serious consequences.

In such an emergency situation, conventionally the pressure control damper 7
and 7' (see Figure 1) to fully open air from between the inertia of the induced blower and the furnace opening, and immediately stop the oxygen injection from the oxygen suction lance, etc., and close the hood. The Co gas inside is combusted by air, and no explosion occurs inside the hood or cooler (because the Co gas reacts with the air and combusts due to its high temperature).

The explosion occurs when Co gas and air are pre-mixed in a certain proportion and instantly combust at a low temperature. ) By filling this combustion gas into the 7-door, it is possible to prevent the previously sucked high purity Co gas from coming into contact with the outside air, thereby preventing an explosion.

That is, the gas flow in the converter exhaust gas treatment equipment is C
Since the flow flows in the order of o gas - combustion gas (inert gas) - outside air, the Co gas and outside air do not come into direct contact and mix, thereby preventing an explosion.

In this way, by interposing combustion gas in the middle (hereinafter referred to as a tampon gas layer), emergency situations can be coped with.

However, in converter exhaust gas treatment equipment that operates in a hermetically sealed or nearly hermetically sealed state, there is no or very little intake of outside air into the equipment, making it impossible to obtain a sufficient layer of tampon gas. Furthermore, since the processing equipment is completely sealed or close to sealed, there is a high negative pressure inside the processing equipment.
This poses a problem in that there is a high risk of outside air intruding into the low-temperature area after the amount of dust removed, increasing the risk of explosion.

To explain this in more detail, in Figure 2, during blowing E
If the induced fan stops for some reason after a certain period of time, the pressure adjustment damper is fully opened and oxygen injection is stopped, so the air volume of the induced fan, which is induced by inertial force, increases rapidly and gradually as shown by curve A. At the same time as the amount of oxygen decreases, the amount of oxygen (curve C) immediately decreases, and the amount of Co gas generated from the converter (curve B) also decreases accordingly.

In the figure, curves F and F' indicate the range of the amount of gas generated in the converter that can be used as inert gas with respect to the total amount of gas corresponding to the amount of rust drawn by the induced blower.

Therefore, in an emergency, as in the past, when the pressure adjustment damper is fully opened and the oxygen injection is stopped at the same time, the range in which a tampon gas layer is generated is curve B, curve F, and curve F'.
There is a technical problem in that a sufficient tampon gas layer cannot be obtained at the intersection of the lines, that is, the range of the lines.

The present invention was made in view of the above-mentioned technical problems, and provides an operating method for obtaining a sufficient tampon gas layer even in a converter exhaust gas treatment equipment that is operated in a sealed or nearly sealed state. It's completely amazing.

That is, in an emergency, the present invention does not completely open the pressure regulating damper and simultaneously stop the oxygen injection as in the conventional case, but instead maintains the opening of the pressure regulating damper at a constant level and opens one emergency air intake port. Open it to suck in outside air, then adjust the amount of oxygen blown in from an oxygen blowing lance, etc.
By adjusting the amount of CO gas generated from the converter,
This CO gas and the above-mentioned suction air are used to generate a sufficient tampon gas layer.

An embodiment of the present invention will be described in detail below. In Figure 3, the vertical axis represents the flow rate of gas flowing through the converter exhaust gas treatment equipment, and the horizontal axis represents time, showing the relationship between the gas flow rate within the equipment and time during an emergency.

In the figure, line A is the amount of gas sucked by the induced blower, curve B is the amount of gas generated from the converter, curve C is the amount of oxygen blown, and line F
, F' is the range of the amount of gas generated from the converter in which inert gas is generated with respect to the amount of suction gas (line A).

The amount of gas generated in the converter in the range of lines F and F' is C
The amount of gas generated by the reaction of O gas and air to become CO2 gas and the amount of 0 in the air that contributed to the combustion of CO gas are equal to the amount of attraction of the induced blower, and the amount is generated from the converter. This refers to the range in which all gases react with air to become CO, a gas.

For example, if there is a lot of converter generated gas on line F, there will be some CO gas that does not react with the air, and if there is less gas on line F', there will be some air that does not react. There is a danger of explosion in either case.

Assume that during blowing, the induced blower stops 8 hours after the start of blowing.

In this emergency, immediately maintain the opening degree of the pressure regulating damper constant. For example, the opening degree of the pressure adjustment damper can be set to the opening degree when the induced blower stops, or the opening degree that will result in the permissible negative pressure inside the processing equipment, which is determined in advance based on the relationship between the inertial operation of the induced blower and the amount of air sucked in. held at a certain degree.

By maintaining the opening degree of the pressure regulating damper in this way, the amount of gas flowing through the exhaust gas treatment device is kept at a constant value as shown by line A for a certain period of time.

Therefore, if the range of lines F and F' is also line A, it is uniquely determined by <i2. The emergency air intake port 13 (see FIG. 1) is opened at the same time as maintaining the opening degree of the pressure regulating damper. For example, automatic lifting of the skirt, opening of the lance through hole, opening of the sealing portion of the lance hole, or opening of a specially provided emergency air intake port 13, etc. are carried out.

In this way, the amount of oxygen blown is gradually reduced as shown by curve C, with a predetermined slope relative to the amount of air sucked. As the amount of blown oxygen gradually decreases, the COi discharged from the converter also gradually decreases as shown by curve B. At this time, curve B and lines F and F'
Any CO gas generated within the intersection with the air reacts with the air to form a layer of CO, gas, and tampon gas.

In FIG. 3, a layer of tampon gas is generated for about 8.5 seconds as indicated by the line.

The embodiment shown in FIG. 4 maintains the pressure regulating damper at a constant opening in the event of an emergency, and at the same time
The operation for opening 3 is the same as in the embodiment shown in FIG.

The difference from the embodiment shown in FIG. 3 is that the amount of oxygen blown is adjusted at the same time as the emergency occurs, and the amount of CO gas generated from the converter that is generated along with this is adjusted to the lines F and F'. The oxygen injection is continued for a certain period of time so that the tampon gas layer enters the tampon, and the generation time (line D) of the tampon gas layer is adjusted by the oxygen injection time.

In this way, by keeping the opening degree of the pressure regulating damper constant and adjusting the amount of oxygen blown, the generation time of the tampon gas layer is lengthened, and a sufficient amount of CO gas is generated by the reaction between CO gas and air. CO, gas is generated.

As detailed above, according to the present invention, in an emergency when the induced blower stops for some reason, the pressure regulating damper is held at a constant opening degree and the emergency air intake port is opened.
By sucking air into the exhaust gas treatment device and temporarily reducing the amount of oxygen blown into the device, or by blowing in an appropriate amount of oxygen for a certain period of time, it is possible to prolong the generation time of the tampon gas layer. A sufficient amount of tampon gas layer can be obtained.

Therefore, even when the exhaust gas treatment equipment is operated in a completely hermetically sealed or nearly hermetically sealed state, a tampon gas layer is completely generated, and the generation of this tampon gas layer prevents the inside of the exhaust gas treatment equipment from becoming excessively negative pressure. There is no air intrusion from any place other than the entrance, and there is no risk of explosion.

As a result, the safety of exhaust gas treatment equipment that operates in a hermetically sealed or nearly hermetically sealed state is increased, and it is possible to recover high-purity CO gas, which has a significant effect on industry. .

[Brief explanation of drawings]

FIG. 1 is an explanatory diagram showing the entire converter exhaust gas treatment apparatus. FIG. 2 is a diagram showing the state of formation of a tampon gas layer when the conventional emergency operation method is applied to a closed exhaust gas treatment device. Figures 3 and 4 show examples of the present invention. Figure 3 shows the case where the amount of oxygen blown is gradually reduced, and Figure 4 shows the case where the amount of oxygen blown is set to be blown for a certain period of time. FIG. 3 is a diagram showing the state of formation of a tampon gas layer in each case. 1... Converter 4... Oxygen injection lance 7... Pressure adjustment damper 8... Induced blower 13... Emergency air intake applicant Nippon Steel Corporation applicant Kawasaki Heavy Industries, Ltd. Figure 2 F Yon\J\4 Ishi ``Ji 1;
sec) Figure 3 FAN stop B1 interval (10ν)

Claims (1)

[Claims] 琲 In the event of an emergency for the converter exhaust gas treatment equipment that operates in a sealed or nearly hermetically sealed state, the damper that controls the pressure inside the exhaust gas treatment equipment should be kept at a constant opening, and the emergency air intake port should be opened. The amount of CO gas generated from inside the furnace is adjusted by sucking outside air into the exhaust gas treatment device and then adjusting the amount of oxygen blown in from an oxygen injection lance, etc.
This generated CO gas and the outside air sucked into the exhaust gas treatment device generate an inert gas layer in the exhaust gas treatment device,
This inert gas layer isolates the CO gas that initially stagnated in the exhaust gas treatment device from the outside air that is subsequently sucked in from the furnace mouth, etc., and quickly removes the stagnant gas in the exhaust gas treatment device. An emergency operating method for a converter exhaust gas treatment device, characterized in that the exhaust gas is discharged outside.