JPH0625373B2 - Gas ingress prevention method for seal device for swivel chute drive in bellless vertical furnace - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION <Industrial field of application> The present invention secures a seal of a water sealing mechanism provided between a rotating part and a fixed part of a swirling chute drive device in a bellless blast furnace, and ensures a drive chamber. The present invention relates to a method for preventing the intrusion of the top gas and dust into the drive chamber and the nitrogen gas supplied to the drive chamber, and a method for preventing the top gas from entering the drive chamber for the swirling chute drive device of the bellless blast furnace. .

<Prior Art> In a blast furnace, a bellless furnace top charging device is used as a furnace top charging device used when charging raw materials such as ore and coke into the furnace. This bellless furnace top charging device is a device for continuously charging and swirling a swirling chute provided in the furnace to distribute and charge the raw material, and it is compact as a whole and the height of the device can be relatively low. Have the advantage of.

Conventionally, in a bellless type vertical furnace, especially in a blast furnace, the gas seal and dust seal for the inside of the rotary table 21 that swivels and tilts the swirling chute 20 as shown in FIG. The rotating table 21
The exhaust gas after being blown into a drive chamber 23 formed in a casing 22 in which the rotary table 21 is cooled, and then the rotary table 21 is cooled, has an annular gap (slit) between the fixed portion 1 and the rotary portion, that is, the cover 3 of the rotary table 21. ) Was discharged into the furnace.

The heat input to the rotary table 21 by the radiant heat from the furnace is at most
It is about 20000 kcal / h, and therefore the amount of gas required for cooling is about 1000 Nm ³ / h, but this supply amount prevents gas and dust from entering the driving chamber 23 in the casing 22 from inside the furnace. I couldn't. 6000 to 10000 Nm ³ / h to ensure that gas and dust ingress is avoided
Cost of nitrogen gas is required.

In order to reduce the amount of cooling gas blown into the drive chamber 23 in the casing 22, means for sealing by providing a sealing device for pressing an elastic body in the slit portion between the fixed portion and the rotating portion of the rotary table 21 (Japanese Patent Laid-Open No. 61- No. 62782, Japanese Utility Model Laid-Open No. 63-123994) or a means for accommodating carbon in the slit and pressing the carbon against the sliding surface to seal it (see Japanese Patent Laid-Open No. 61-87807). There is.

However, since these sealing means press the elastic body and carbon against the sliding surface, it is difficult to maintain the sealing function for a long period of time due to severe wear. Moreover, since the sealing performance is insufficient, a large blast furnace with a high pressure is required. In the case of, the gas flow rate in the vertical direction at the center of the furnace top is large, and in the end there is a problem in that a cooling gas supply of, for example, 2000 Nm ³ / h or more must be performed only for the purpose of preventing intrusion of gas and dust in the furnace. there were.

In order to deal with such a problem, Japanese Utility Model Laid-Open No. 63-119650 discloses means for sealing by providing a water sealing mechanism including a combination of a water sealing trough and a partition plate arranged in the water sealing trough. There is.

That is, as shown in FIG. 2, an annular water sealing gutter 10 is integrally provided on an upper part of a rotary table 21 housed in a drive chamber 23 formed in a casing 22 at the top of a blast furnace, and a fixed portion 1 is provided with a water sealing gutter. Ten
A partition plate 11 arranged inside is integrally provided. The cooling water required for water sealing is boosted by the water supply pump 4, and while the amount of cooling water is measured by the water supply flow meter 8, the opening degree of the water supply flow rate control valve 7 is adjusted and the upper water is supplied from the water supply pipe 12 provided in the fixed part 1. Supplied to the sealing gutter 10.

Further, an annular water-sealing gutter 2 is integrally provided on the fixed portion 1 corresponding to the lower part of the rotary table 21, and a connecting space 24 from the water-sealing gutter 10 provided on the upper part of the rotary table 21 (this is used for cooling the rotary table). The cooling water necessary for the water seal is always supplied to the lower water seal gutter 2 via the above. On the other hand, the rotary table 21 is integrally provided with a partition plate 5 arranged in the water sealing trough 2, and water is sealed by the water sealing trough 2 and the partition plate 5 submerged in the sealing water, and the fixed portion 1 and the rotating portion are separated from each other. Seal the gap. Further, a drain pipe 6 for discharging the cooling water is provided outside the system in the lower water sealing gutter 2 for draining.

By the way, since the pressure inside the blast furnace is high, in order to prevent the furnace top gas from entering the driving chamber 23 formed in the casing 22 by the upper water sealing gutter 10 and the lower water sealing gutter 2, the driving chamber
While controlling the N ₂ gas flow rate control valve 29 from the nitrogen gas supply pipe 25 into the chamber 23, the nitrogen gas (N ₂ gas) was supplied to increase the pressure to balance the furnace top pressure and cool the drive chamber 23. .

However, due to the small fluctuations in the top pressure, a breathing phenomenon was observed in the sealing water in the water sealing troughs 10 and 2, and the water sealing pressure by the water sealing mechanism was only 150 to 200 mmAq. There was a problem that the water seal was often broken when it occurred.

If the water seal breaks, overflow from the water seal gutter will enter the furnace,
Not only will it enter the casing, but sealing by water sealing will not be possible, and gas and dust in the furnace will enter the casing and adversely affect the drive device of the rotary table.

<Problems to be Solved by the Invention> Therefore, conventionally, the pressure detection pipes 27a and 27b connected to the differential pressure gauge 26 are respectively inserted into the casing 22 and the furnace top wall 30, and the pressure P ₂ in the drive chamber 23 and the furnace Furnace pressure P ₁ inside the top wall 30
And the differential pressure ΔP between the positive pressure and the negative pressure is detected, and the nitrogen gas is supplied from the nitrogen gas supply pipe 25 so that the differential pressure ΔP becomes equal to or higher than the set value p of the positive pressure, that is, ΔP = P ₂ −P ₁ p0.

Specifically, the differential pressure gauge 26 takes out the differential pressure ΔP as a process pressure variable and inputs it to the pressure regulator 28a.
p and the above-mentioned positive differential pressure set value p from the pressure controller 28a
The operation signal MV value is calculated with the operation signal MV value, and the opening degree of the cooling N ₂ purge control valve 29 is controlled by the operation signal MV value to drive the driving chamber 23.
The pressure inside the furnace top 27 was set to be higher than the positive differential pressure setting value p. However, due to the above operation, the pressure difference Δ between the pressure P _{2 in the} drive chamber 23 and the pressure P ₁ in the furnace is always Δ.
In order to control the N ₂ gas purge amount so that P becomes larger than the differential pressure set value p, it was uneconomical to follow the pressure fluctuation of the reactor internal pressure unless a large flow rate of N ₂ gas was supplied.

The present invention solves the above-mentioned problems of the prior art, secures a seal of a water sealing mechanism provided between a rotating part and a fixed part of a swirling chute drive device, and intrudes a furnace top gas or dust into a drive chamber. It is an object of the present invention to provide a method for preventing intrusion of top gas into the drive chamber for a swirling chute drive device in a bellless blast furnace, which can reliably prevent N ₂ gas supplied to the drive chamber. is there.

<Means for Solving the Problems> According to the present invention for achieving the above object, a rotary table for swiveling and tilting a swirling chute is installed in a casing at the top of a furnace, and fixed at an upper part and a lower part of the rotary table. For a swirling chute drive device in a bellless vertical furnace equipped with a water-sealing mechanism formed by combining an annular water-sealing trough and an annular partition plate arranged in the water-sealing trough between a rotating part and a rotating part A method of preventing gas intrusion into the furnace of a sealing device, wherein the drain pipe taken out of the lower water sealing gutter to the outside of the furnace is immersed in the drainage stored in a drain tank having a sealed structure, and the upper part of the drain tank is used. While connecting the furnace top casing with the rotary table airtightly connected by a communication pipe, while guiding the drainage from the lower water sealing gutter into the drainage tank via the drainage pipe,
The drainage stored in the drainage tank is extracted so that the differential pressure between the gas pressure in the furnace top casing and the gas pressure in the furnace is maintained at a positive differential pressure setting value or more. A method for preventing intrusion of gas into a furnace of a seal device for a swirling chute drive device in a bellless vertical furnace, which is characterized by controlling a gas volume.

<Operation> While guiding the drainage from the lower water sealing gutter into the drainage tank through the drainage pipe, the drainage stored in the drainage tank is adjusted in the drainage tank with a large volume by adjusting the amount of extraction from the drainage tank. The drainage level, that is, the volume of gas in the drainage tank is controlled, thereby maintaining the differential pressure between the gas pressure in the furnace top casing and the gas pressure in the furnace above a predetermined positive pressure. Thus, the gas in the furnace from the inside of the furnace into the drive chamber through the seal device for the swivel chute drive device is prevented.

The principle of the present invention is that the drive chamber formed in the furnace top casing, which is affected by the fluctuation of the furnace pressure P _{1 at} the furnace top via the water sealing mechanism, is connected to the drain tank via the communication pipe, and the drain tank is connected. The essence is to control the gas volume by controlling the level of the drainage stored inside, and thereby control the pressure in the drive chamber.

That is, assuming that the gas volume of the driving chamber is V _m and the gas volume occupied by the drainage in the drainage tank is V _T , the total gas volume is V _m.
It becomes + V _T. Here, in order to compensate for and counter the fluctuation of the furnace top pressure P ₁ , it is sufficient to control so that P ₁ × (V _m + V _T ) = C (constant value). Here, since V _m and C is a constant value, to reduce the waste water tank gas volume V _T the greater the Roitadaki圧P _1, so as to increase the V _T smaller the Roitadaki圧P ₁ in the opposite It will be operated.

<Example> An example of the present invention will be described below with reference to the drawings. First
In the figure, the opening of the feed water flow rate control valve 7 is adjusted while measuring the amount of cooling water by the feed water flow meter 8 while measuring the amount of cooling water by the feed water pump 4, and the cooling water (for example, factory return water) necessary for water sealing is fixed. It is supplied to the upper water seal gutter 10 from the water supply pipe 12 provided in the.
The cooling water supplied to the upper water seal gutter 10 is always supplied to the lower water seal gutter 2 through the connecting pipe 24 (which is used for cooling the rotary table 21) to supply the cooling water necessary for the water seal. Has become.

Further, a drain pipe 6 for discharging cooling water to the outside of the system is connected to the lower water sealing gutter 2 to form water cooling water, while a nitrogen gas supply pipe 25 is connected to the furnace top casing 22. It is the same as the conventional example shown in FIG. ₂ that the N ₂ gas supply system for supplying the nitrogen gas into the drive chamber 23 is formed while adjusting the opening degree of the N ₂ gas flow valve 29. A furnace in which a drain pipe 6 taken out of the lower water gutter 2 to the outside of the furnace is immersed in the drain water 13 once stored in a drain tank 9 having a closed structure, and an upper portion of the drain tank 9 and a rotary table 21 are installed. The top casing 22 is connected to the top casing 22 by a communication pipe 14 in an airtight manner. On the other hand, a drainage sampling pipe 15 is connected to the lower end of the drainage tank 9, and the drainage pump 16 stores the drainage in the drainage tank 9 while measuring the amount of drainage with a drainage flow meter 17 arranged in the drainage sampling pipe 15. Drained 13
A drainage system that discharges is formed. In addition, drainage tank 9
A drainage level meter 18 is provided in the tank to measure the level of the drainage 13 stored in the drainage tank 9.

In the present invention, the nitrogen gas supplied from the nitrogen gas pipe 25 into the casing 22 is biased at a constant low flow rate with the N ₂ gas flow rate control valve 29 set to a small opening. A differential pressure gauge 26 connected to the pressure detection pipe 27a inserted into the furnace top casing 22 and the pressure detection pipe 27b inserted into the furnace top wall 30.
The differential pressure ΔP between the pressure P ₂ inside the drive chamber 23 and the furnace internal pressure P ₁ is detected by and the differential pressure ΔP is taken out as a process variable and ΔP is a positive set value p or more, that is, ΔP = P ₂
-Drain pipe 6 from lower water gutter 2 to become P ₁ p0.
Through the drainage tank 9 through the drainage tank 9
The amount of drainage that drains the drainage stored in the drainage pipe 15 is adjusted. At this time, the drainage from the drainage pipe 15 is performed by controlling the rotation speed of the drainage pump 16 so that a predetermined amount of drainage is obtained while being measured by the drainage flow meter 17.

Specifically, the differential pressure ΔP as the process variable taken out by the differential pressure gauge 26 is guided to the pressure regulator 28b, and is adjusted in advance by the regulator.
Compare with the positive differential pressure setting value p input to 28b,
Based on this comparison result, an operation signal (MV value) is given to the level controller 31 having a cascade control configuration, and the level controller 31
An operation signal (MV value) issued from 31 is controlled in rotation speed of the drainage pump 16 via the rotation speed controller 19 to adjust the amount of drainage discharged from the drainage tank 9. The level signal of the wastewater 13 detected by the drainage level meter 18 provided in the drainage tank 9 is received by the level controller 31.
It is designed to grasp the drainage level inside.

For example, when the differential pressure ΔP <p, the gas pressure in the drive chamber 23 decreases, and the fine fluctuations in the furnace pressure cause a phenomenon in which the water seal water stored in the upper water seal gutter 10 and the lower water seal gutter 2 breathes. When the internal gas may enter the drive chamber 23, the rotation speed of the drainage pump 16 is set to a low speed via the pressure controller 28b, the level controller 31, and the rotation speed controller 19 to drain the water tank 9.
Reduce the amount of drained water.

Thus, the amount of drainage guided from the lower water gutter 2 to the drainage tank 9 is made larger than the amount of drainage drained from the drainage tank 9 to raise the drainage level in the drainage tank 9, thereby decreasing the gas volume V _T in the drainage tank 9. , Drainage tank 9
The gas inside is introduced into the casing 22 through the communication pipe 14 to increase the pressure in the drive chamber 23.

On the contrary, in order to prevent an abnormal situation in which the gas pressure in the drive chamber 23 is too high, the drain pump 16
The rotation speed of is set to a high speed to increase the amount of drainage from the drainage tank 9 to lower the drainage level in the drainage tank 9, increase the gas volume in the drainage tank 9 and guide the gas in the casing 22 into the drainage tank 9. The operation is performed by reducing the gas pressure in the drive chamber 23.

The control as described above is performed when the drainage level in the drainage tank 9 is within the range between the upper limit level (L _h ) and the lower limit level (L _l ) and when the drainage level exceeds the upper limit level (L _h ). Alternatively, when it is lower than the lower limit level (L ₁ ), the operation of controlling the gas volume V _T in the exhaust gas tank 9 by the rotation speed control of the drainage pump 16 by the rotation speed controller 32 is not performed and the conventional example described in FIG. According to the signal MV value from the gas pressure adjuster 28a, the opening degree of the N ₂ gas flow rate adjusting valve 29 provided in the N ₂ gas pipe 25 is increased and the amount of nitrogen gas supplied into the drive chamber 23 is changed. Control gas pressure.

While the control by the nitrogen gas supply is being performed, the rotation speed controller 32 controls the rotation speed of the drainage pump 16 to control the drainage level in the drainage tank 9, and the level is set to L _h.
And L ₁ , the gas volume V in the exhaust gas tank 9 is recovered.
_It goes without saying that the control by _T is prepared.

In the above-mentioned embodiment, the case where the amount of drainage discharged from the drainage tank is adjusted by the rotation speed controlled drainage pump arranged in the drainage extraction pipe has been described, but the drainage amount control from the drainage tank is arranged in the drainage extraction pipe. It can be similarly performed by other drainage means such as a flow rate control valve.

<Effects of the Invention> As described above, according to the present invention, not only the intrusion of the gas in the furnace from the seal device for the swivel chute drive device into the drive chamber can be reliably prevented, but also the amount of nitrogen gas used is significantly reduced. However, the effect obtained is enormous.

[Brief description of drawings]

FIG. 1 is a sectional view showing a sealing device for a swiveling chute driving device according to an embodiment of the present invention, FIG. 2 is a sectional view showing a sealing device for a swiveling chute driving device according to a conventional example, and FIG. 3 is a chute driving device. FIG. 1 ... Fixed part, 2 ... Lower water gutter, 3 ... Cover, 4 ... Water supply pump, 5 ... Partition plate, 6 ... Drain pipe, 7 ... Water supply control valve, 8 ... Water supply flow rate Total, 9 ... Drainage tank, 10 ... Upper water gutter, 11 ... Partition plate, 12 ... Water supply pipe, 13 ... Drainage, 14 ... Communication pipe, 15 ... Drainage extraction pipe, 16 ... Drainage Pump, 17 ... Drainage flow meter, 18 ... Drainage level meter, 19 ... Rotation speed controller, 20 ... Rotating chute, 21 ... Rotary table, 22 ... Casing, 23 ... Drive room, 24 ... Connection pipe, 25 …… N ₂ gas supply pipe, 26 …… Differential pressure gauge, 27 …… Pressure detection pipe, 28 …… Pressure regulator, 29 …… N ₂ gas flow control valve, 30 …… Top wall of furnace, 31 ...... Level controller.

Claims (1)

[Claims] 1. A rotary table for swiveling and tilting a swirling chute is installed in a casing at the top of a furnace, and an annular water-sealing gutter and an annular water trough are provided between a fixed part and a rotary part at the upper and lower parts of the rotary table. A method for preventing gas intrusion in a furnace of a seal device for a swirling chute drive device in a bellless type vertical furnace equipped with a water sealing mechanism that is combined with an annular partition plate arranged in a water sealing trough, wherein While immersing the drain pipe taken out of the reactor from the water sealing gutter into the drainage stored in the drainage tank of the closed structure, the upper part of the drainage tank and the furnace top casing in which the rotary table is installed are connected by a communication pipe. Airtightly connected, while guiding the drainage from the lower water gutter into the drainage tank through the drainage pipe, the differential pressure between the gas pressure in the furnace top casing and the gas pressure in the furnace is a positive differential pressure. Maintain above the set value The drainage stored in the drainage tank is controlled so as to control the gas volume in the drainage tank. Method.