JPH0321605B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention consists of a housing with one gas inlet and two gas outlets, a shutoff device with an actuating device, and a measuring and control device, and which is capable of suppressing transient pressure fluctuations. The present invention relates to a device for switching the flow of gas leaving a converter from a gas incinerator to a gas reservoir and vice versa without combustion.

In converter operation, during the blowing stage,
CO with a calorific value of 8000kJ/ ^Nm3 or more
Contained gas is generated which, after suitable cleaning, is collected in a gas reservoir for further use. On the other hand, at the beginning and end of the blowing stage and during the stopping period of blowing, there are few flammable control components;
Or, because it contains atmospheric air, an otherwise unusable gas is generated, which is also cleaned and discharged from the gas incinerator to the atmosphere. In order to handle these two types of gas, it is necessary to provide a switching device within the exhaust gas conduit.

Also, during the operation of the converter, the exhaust gas not only changes in its composition throughout the cycle, but also in its quantity. Therefore, it becomes necessary to adjust the output of the blower to the amount of exhaust gas.

For exhaust gas cleaning, so-called scrubbers can be used, but during gas incineration operations the pressure loss through the scrubber reaches approximately 200 mbar. Dry electrostatic precipitators, on the other hand, have a pressure drop of only approx.
It has the advantage of being 20 mbar.

However, by switching to the supply operation to the gas reservoir, the pressure loss is, for example, 20 mbar in both wet and dry dust collectors.
For this reason, in plants with wet mechanical dust collectors, the pressure difference that the blower has to overcome is approximately 10%.
However, for plants equipped with dry dust collectors (which are preferred since they require substantially less power), the change in pressure drop amounts to approximately 100%. Thus, in a plant equipped with a wet dust collector, switching from a gas incinerator to a gas reservoir and vice versa is less difficult in terms of control technology than in a plant equipped with a dry dust collector. It will be easily understood. In the former case,
Since the dust collector acts like a throttle, the effects of transient pressure fluctuations due to switching can hardly reach upstream of the flow in the region of the suction hood above the converter. In the latter case, on the other hand, the switching device essentially has to be carefully designed and the control device of the blower has to be operated more precisely if disturbances in the pressure relationship in the area of the suction hood are to be eliminated. No.

German Patent Publication (DE-AS) No. 1433688 states:
An apparatus for recovering unburned exhaust gas from an oxygen top-blown converter is disclosed, in which the exhaust gas is sucked by a suction blower;
Optionally, a portion is fed into a gas reservoir and a portion is blown into the atmosphere. At this time, the inside of the conduit leading to the gas reservoir and the inside of the blowout conduit for blowing out into the atmosphere are provided with switching valves connected so as to move in opposite directions,
Furthermore, a chimney valve is provided in the outlet conduit spaced apart in the direction of the gas flow. Further, a flute-shaped valve visible in the direction of gas flow in the blow-off conduit and distant from the blow-off conduit is connected to the blow-off conduit through a controller.
It is connected to a differential pressure gauge connected to a discharge conduit located between the individual chimney valves. This device is designed so that the pressure difference measured by the differential pressure gauge is maintained at zero during gas blow-off and switching;
The switching of the individual connected flow valves is controlled to occur slowly at first and then progressively faster.

This known switching device is relatively expensive and complex. Their disadvantages are, among other things, poor control characteristics. This known device is unsuitable for use in plants with dry dust collectors. The reason for this is that transient pressure fluctuations necessarily occur during the switching process and, furthermore, that the gas pressure and gas flow rate under operating conditions cannot be well controlled.

Therefore, there is a need for a device of the type mentioned at the outset, which does not have the above-mentioned disadvantages and which, moreover, can be switched without transient pressure fluctuations even in plants equipped with dry dust collectors. The challenge is to create one. This device should be as simple and inexpensive as possible and should have suitable control characteristics to ensure alternately complete and sealed shut-off of the gas lines leading to the gas incinerator and the gas reservoir, respectively.

This problem is solved according to the present invention, in which two exhaust ports connected to the gas incineration tower and the gas reservoir are provided with operating devices that operate independently of each other, and
The solution is provided by devices of the type described above, each of which is equipped as a shut-off device with a bell-shaped valve whose characteristics are essentially identical to each other.

Preferably, the bell-shaped valves have flow cross-sections of approximately the same size. Preferably, the bell valve is made of metal and metal packing and can withstand a closing pressure of at least three times the pressure of the gas reservoir.

However, the device according to the invention has the advantage that only two control elements are required, which simultaneously adjust the switching operation and reliably block the two discharge conduits alternately.

In other words, the gas flow of the converter can be switched between the two cases without pressure fluctuations, thanks to the shape of the bell valve, which has mutually identical properties. Thanks to the mutually independent actuating devices belonging to the bell valve, control of the required dynamic pressure increase as well as the static pressure in the gas reservoir conduit is also ensured. Note that this is a premise for avoiding overflow of gas from the suction hood on the converter during the above switching operation.

The details and advantages of the device according to the invention will be described based on the specific example shown in the drawings.

In FIG. 1, a housing is indicated at 10, into which a gas conduit 4 opens, and from which two gas conduits 7 and 8 are opened.
is extending. Gas from the converter is supplied to the housing 10 by a blower 3 and bell valves 1 and 2
Depending on the degree of opening, it is further sent via conduit 7 to a gas reservoir or via conduit 8 to gas incineration tower 9. The actuating devices for bell valves 1 and 2 are designated 5 and 6, respectively.

At the valve opening shown in FIG. 1A, the conduit 8
The gas outlet leading to and thus to the gas incineration tower is fully open, while the gas outlet leading via valve 1 to conduit 7 is closed. Such a valve opening corresponds to stage 1 in FIG.

FIG. 1B shows the beginning of the switching process,
Valve 1 is still fully closed and valve 2 is somewhat closed. In FIG. 1C, valve 2 is further closed and valve 1 is already somewhat open. Both FIGS. 1B and 1C show certain instantaneous conditions during switching phase 2 shown in FIG.

In FIG. 1D, valve 2 is fully closed, while valve 1 is now fully opened. As a result, the gas outlet leading to conduit 8 and thus to gas incineration tower 9 is closed, while the gas outlet leading to conduit 7 and thus to the gas reservoir is fully open. The actuating devices 5 and 6 for the bell valves 1 and 2 respectively operate independently of each other, so that a transition between the two operating states of the switching device is possible without any transient pressure fluctuations.

The two bell-shaped valves 1 and 2 have a special external shape, as shown in an enlarged view in FIG. 2A. Figure 2B shows its control characteristics, and the characteristic value
kv is plotted against valve opening. Since the control characteristics of the two bell-shaped valves are substantially identical and they operate independently of each other, satisfactory switching between the two cases is possible under all expected operating conditions.

FIG. 3 shows the switching process as a function of time (steps). FIG. 3B shows curves V ₁ and
V ₂ designates the valve opening of the bell valves 1 and 2 during the gas incineration operation (stage 1), during the switching (stage 2) and during the supply operation to the gas reservoir (stage 3). ing. Note that the pressure relationship in this case is shown in FIG. 3A.

In the state of stage 1 shown in FIGS. 1A, 3A and 3B, the pressure in front of the bell valve 1 is, for example, 2 mbar higher than the ambient pressure, as shown in FIG. 3A. Also, during the supply operation to the gas reservoir, ie in the state of stage 3 shown in FIGS. 1D, 3A and 3B, the reservoir pressure is, for example, 5 mbar higher than, for example, 40 mbar.

Then, in the intervening stage 2 shown in FIGS. 3A and 3B, when the valve 2 closes to a position where the pressure applied to the valve 1 reaches the predetermined value, the valve 1 begins to open and the supply to the gas reservoir is interrupted. begins. Thereafter, as shown in FIG. 3B, valve 1 opens at a constant speed, and valve 2 continues to move in the fully closed direction. Valve 2 then closes completely when valve 1 reaches its fully open position. Note that when switching to the gas incineration operation, first the valve 1 moves to the fully closed position, and at the same time as the valve 1 is fully closed, the valve 2 opens.

By using the device of the present invention, the gas flow from the converter can be quickly switched from gas incineration operation to gas reservoir supply operation and vice versa without any transient pressure fluctuations. And it can be done reliably. This device is relatively simple in construction and performs control and sealing functions at the same time.

To summarize the invention, an apparatus is proposed for switching the exhaust gas flow from a converter from a gas incineration operation to a gas reservoir supply operation and vice versa without transient pressure fluctuations. , this device is also particularly suitable for plants equipped with dry dust collectors.

The device has a housing with a gas inlet and two gas outlets, each of which is equipped with an actuator that operates independently of the other and has substantially identical characteristics. A shaped valve is provided for each.

[Brief explanation of drawings]

Figures 1A to 1D are schematic diagrams showing the opening degrees of two bell-shaped valves in different operating states, Figure 2A is a simplified diagram showing the structure of the bell-shaped valve, and Figure 2B is the bell-shaped valve. FIG. 3A shows the temporal variation of the pressure relationship during the switching process, and FIG. 3B shows the temporal variation of the bell valve opening. In addition, in the symbols used in the drawings, 1, 2
...Bell-shaped valve (shutoff device), 3...Blower, 4...
...Gas conduit (gas inlet), 5, 6... Actuation device,
7, 8...Gas conduit (gas discharge port), 9...Gas incineration tower, 10...Housing.

Claims (1)

[Scope of Claims] 1. Consists of a housing each equipped with one gas inlet and two gas outlets, a shutoff device with an actuating device, and a measuring and control device, and which allows the gas to flow without transient pressure fluctuations. In a device for switching the flow of gas exiting a converter from an incinerator to a gas reservoir and vice versa, bell-shaped valves having actuators that work independently of each other and having substantially the same characteristics as each other are used as shutoff devices for the two gas outlets. A device that switches the gas flow that each device has. 2. The device for switching gas flow according to claim 1, wherein the two bell-shaped valves form flow cross-sections of approximately the same size. 3. A device for switching gas flow according to claim 1 or 2, wherein said bell valve is made of metal and a metal packing and has a closing pressure of at least three times the pressure of said gas reservoir.