JPH08134520A - Device for discharging and carrying powdery and granular body - Google Patents

Abstract

PURPOSE: To stabilize the control of discharging quantity of an L valve by regulating the pressure difference between the pressures on the upstream side and on the downstream side of the L valve to zero. CONSTITUTION: A pressure equalizing pipe 6 for connecting the front side and the rear side of the L valve 7 is arranged and an exhausting pressure regulating device 5 is arranged in the pressure equalizing pipe 6 to regulate the pressure difference between the pressure P2 on the upstream side and the pressure P1 on the downstream side of the L valve 7. By this method, in a smelting reduction furnace, there is such an effect that the pre-reduced ore can stably be taken out from a pre-reduction furnace 32, and the like.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a powder and granular material cutting and transferring device, and more particularly to a powder and granular material cutting and transferring device suitable for stably extracting pre-reduced ore from a pre-reduction furnace. is there.

[0002]

2. Description of the Related Art FIG. 3 is an explanatory diagram showing an example of a conventional smelting reduction equipment for iron ore proposed by Japanese Patent Laid-Open No. 1-149912. In the figure, reference numeral 31 is a smelting reduction furnace, which constitutes this smelting reduction equipment together with a fluidized bed type preliminary reduction furnace 32. In this smelting reduction equipment,
The iron ore is first charged into the preliminary reduction furnace 32, preheated and preliminarily reduced, and then supplied to the smelting reduction furnace 31.

In the smelting reduction furnace 31, coal and lime are charged in addition to the pre-reduced iron ore, and oxygen is blown in, and the iron ore is smelt-reduced to become hot metal. Next, the reducing high-temperature gas generated in the smelting reduction furnace 31 is dedusted by the dust remover 30, then introduced into the preliminary reduction furnace 32, and used for preheating and preliminary reduction of iron ore.

In this type of technology, FIG.
A pre-reduction furnace such as that shown in is used. 3 and 4
As shown in FIG. 3, the preliminary reduction furnace 32 is provided with a dispersion plate 34 having a dispersion plate nozzle 33, which is a large number of gas passage holes for ejecting gas, inside the preliminary reduction furnace 32. Iron ore is charged into the chamber 35, and exhaust gas, which is a reducing gas, is introduced from the smelting reduction furnace 31 into a wind box 36, which is a gas blowing chamber below the dispersion plate 34. This reducing gas is blown out to the upper preliminary reducing chamber 35 through the dispersion plate nozzle 33 of the dispersion plate 34, whereby a fluidized bed 37 is formed,
The iron ore is preheated and pre-reduced.

In this equipment, of the high temperature powdery iron ore preheated and prereduced in the preliminary reduction furnace 32, the fine iron ore having a particle size of about 0.3 mm or less is classified and the freeboard part 9 is raised. , And is discharged to the outside of the system according to arrow F. On the other hand, a so-called coarse iron ore having a larger particle size than that forms a fluidized bed 37 and remains in the pre-reduction furnace 32 as it is. And it is necessary to quantitatively discharge it out of the furnace by the device.

As one of the methods, the fluidized bed 3 is provided at the outlet.
7 There is a method of installing coarse iron ore that overflows outside the furnace.

By the way, the ore such as iron ore and chrome ore supplied to the preliminary reduction furnace 32 is an iron ore for sintering raw material called so-called sintering field having a particle size of about 8 mm or less. There is also iron ore with a large particle diameter of about 20 mm to about 30 mm. Since fluidization of large-sized iron ore and the like is slightly inactive and tends to accumulate at the bottom of the fluidized bed 37, in the overflow method, such coarse iron ore and the like should be smoothly discharged out of the system. Is difficult Iron ore and the like retained at the bottom of the fluidized bed 37 without being discharged to the outside of the system are reduced by the reducing gas, and as a result, metallic iron or the like is generated,
Sticking of iron ore or the like occurs in the furnace to form a lump, which hinders stable fluidization in the fluidized bed 37, and eventually stable operation of the preliminary reduction furnace 32 becomes impossible. Therefore, in order to facilitate the discharge of coarse iron ore etc. out of the system,
It is necessary to stably and continuously discharge coarse iron ore or the like from the bottom of the fluidized bed 37, and some quantitative discharging device is required.

As such a powdery or granular material transferring device, from the viewpoints of simplicity of structure, prevention of lowering of the temperature of the powdery or granular material, easiness of coping with occurrence of trouble, etc. It is preferable to use a so-called pneumatic transfer type granular material transfer device for transferring, and therefore, it is adopted for discharging ore from the preliminary reduction furnace of the smelting reduction equipment.

An L valve is known as a type that is often applied to the essential parts of these pneumatic conveying type powder and granular material conveying devices.
FIG. 5 is a vertical sectional view of the L valve. In the figure, reference numeral 7 is an L valve, which is a vertical pipe stand pipe 3
And the horizontal pipe 2 connected to the lower end of the stand pipe 3.
2 and. A gas such as nitrogen or air is blown into the lower portion of the stand pipe 3 from the aeration device 23 to quantitatively cut out the granular material.

[0010]

However, in such a conventional L valve 7, if there is a pressure difference before and after the L valve 7, the cutting performance deteriorates. That is, the downstream pressure P1
When the pressure P2 on the more upstream side is low, the powdery iron ore or the like is cut out from the low pressure portion to the high pressure portion, and a reverse pressure acts on the powdery iron ore or the like to increase the amount of gas required for the aeration device 23. On the contrary, when the pressure P2 on the upstream side is higher than the pressure P1 on the downstream side, it becomes easier for the granular iron ore or the like to flow, and even if the gas amount used in the aeration device 23 is small, L
When a gas other than the aeration gas is introduced from the upstream side of the valve 7, a so-called inflow phenomenon occurs in which the amount of cut out of iron ore powder or the like becomes abnormally high. And
Furthermore, even if the aeration gas is cut, it is difficult to stop the cutting of the powdered iron ore or the like.

For this reason, when the L valve 7 is used to cut and discharge from the bottom of the fluidized bed 37 of the preliminary reduction furnace 32, the L valve 7 is used to ensure stable cutting performance.
It is conceivable to provide the pressure equalizing pipe 6 in order to eliminate the pressure difference between the upstream side and the downstream side. In this case, one end of the pressure equalizing pipe 6 needs to be connected to the discharge side of the L valve 7 and the other end needs to be connected near the outlet of the L valve 7, but if the pressure equalizing pipe 6 is connected near the outlet of the L valve 7. As shown in FIG. 5, the granular iron ore or the like in the pre-reduction furnace 32 is clogged with the pressure equalizing pipe 6 to cause blockage, so that the granular iron ore or the like does not actually enter the pressure equalizing pipe 6 as shown in FIG. It is necessary to connect the end of the pressure equalizing pipe 6 to the freeboard portion 9 which is sufficiently higher than the height of 37.

Here, P1; pressure on the downstream side of the L valve 7; P2; pressure on the upstream side of the L valve 7; pressure on the freeboard section ΔPb; pressure loss in the fluidized bed P1 = P3, P3 = P2-ΔPb , P1 = P2-ΔPb (1) and the pressure loss ΔPb is more downstream than the upstream side of the L valve 7.
Just because it always becomes low, inflow of powdered iron ore, etc.,
The stopping performance is deteriorated, and the predetermined cutout performance accuracy cannot be obtained.

The present invention has been made to solve the above problems, and an object thereof is to provide a device for eliminating the pressure difference between the upstream side and the downstream side of the L valve.

[0014]

A powder and granular material cutting and transferring device according to the present invention is of an L valve type which comprises a stand pipe, a horizontal pipe connected to the lower end of the stand pipe, and a gas blowing device under the stand. The cut-out transfer device is characterized in that a pressure equalizing pipe connecting the front and rear of the L valve is provided, and the pressure equalizing pipe is provided with an exhaust pressure adjusting device.

[0015]

The pressure difference between the upstream side and the downstream side of the L valve is almost equal to the fluidized bed pressure loss ΔPb. ΔPb is determined by the amount of ore retained in the preliminary reduction furnace, but since the amount of ore retained is determined by the operating condition of the preliminary reduction furnace, the pressure loss ΔPb in the fluidized bed constantly fluctuates during operation. However, this pressure loss ΔP in the fluidized bed
b is calculated as follows.

In FIG. 5, P4; pressure in the wind box ΔPd; pressure loss at the dispersion plate ΔPt; pressure in the wind box P4-pressure of the freeboard portion P3 ΔPb = (P4-P3) -ΔPd (2) = ΔPt-ΔPd, and the pressure loss in the fluidized bed ΔPb is the pressure loss in the dispersion plate calculated from the measurable pressure in the wind box P4, the pressure P3 in the freeboard section, and the flow rate and temperature of the reducing gas from the smelting reduction furnace. It can be obtained by ΔPd.

The pressure loss Δ in the fluidized bed thus measured
The same value as Pb is set by the exhaust pressure adjusting device so that the pressure on the downstream side of the L valve is always higher than the pressure on the freeboard section by the same amount as the pressure loss ΔPb in the fluidized bed, and the upstream side of the L valve. By changing the opening degree of the valve of the exhaust pressure adjusting device so that the pressure difference between the downstream side and the downstream side becomes zero, a so-called flow-in situation or a reverse pressure situation is avoided.

[0018]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS FIG. 1 is a vertical sectional view of the vicinity of an L valve showing an embodiment of the present invention. As shown in the figure, the powdery iron ore or the like reduced in the preliminary reduction furnace 32 passes through the coarse iron ore extracting port 2 and is stably extracted quantitatively by the L valve 7, and the coarse ore extracting tank 4 Temporarily stored in. Here, a pressure equalizing pipe 6 and a discharge pressure adjusting device 5 are provided which have an action of making the pressure P2 on the upstream side of the L valve 7 and the pressure P1 on the downstream side substantially equal. The L valve upstream pressure equalizing pipe end 10 of the pressure equalizing pipe 6 is joined to the freeboard portion 9 above the fluidized bed 37 of the preliminary reduction furnace 32, and the L valve downstream side pressure equalizing pipe end 1 is connected.
1 is joined to the upper part of the coarse grain ore extraction tank 4,
Further, the exhaust pressure adjusting device 5 is provided in the middle of the pressure equalizing pipe 6. The wind box internal pressure sensor 12 is provided in the wind box 36 to measure the pressure P4 in the wind box 36, and the freeboard portion pressure sensor 13 is provided at the L valve upstream side equalizing pipe end 10 to provide the freeboard portion of the freeboard portion. The pressure P3 is measured. Further, a reducing gas flow rate / thermometer 14 for measuring the flow rate and temperature of the reducing gas is installed in the reducing gas supply duct 38 to the preliminary reducing furnace. And the air box pressure sensor 12, the freeboard section pressure sensor 13, and the reducing gas flow rate / thermometer 1
The measured value of 4 is input to the control unit 15. The output from the control unit 15 is input to the exhaust pressure adjusting device 5.

The control unit 15 calculates the density ρ of the reducing gas and the flow velocity u at the dispersion plate nozzle 33 from the measured values of the gas flow rate and the temperature of the reducing gas flow rate / thermometer 14, and calculates the dispersion plate pressure loss ΔPd (3 ), The calculated dispersion plate pressure loss ΔPd and the measured pressure P in the wind box 36.
The pressure loss ΔPb in the fluidized bed is calculated from Equation 4 and the pressure P3 of the freeboard portion 9 according to the equation (2).

ΔPb = (P4-P3) −ΔPd (2) ΔPd = (ρ / 2g) × (u / c) ² (3) where ρ: gas density g: gravitational acceleration u: dispersion Gas flow velocity at plate nozzle c: coefficient The calculated value of the pressure loss ΔPb in the fluidized bed is set in the exhaust pressure adjusting device 5, and the valve opening of the exhaust pressure adjusting device 5 is adjusted.
The pressure P1 on the downstream side of the L valve 7 is set to be higher than the pressure P3 on the freeboard portion by ΔPb to eliminate the pressure difference between the pressure P2 on the upstream side of the L valve 7 and the pressure P1 on the downstream side. . Reference numeral 8 is a compressed air pipe, which supplies a power source and the like necessary for a positioner and the like built in the exhaust pressure adjusting device 5.

When there is a pressure difference between the pressure P2 on the upstream side of the L valve 7 and the pressure P1 on the downstream side, a so-called flow-in situation may occur or a back pressure may be applied. This phenomenon is avoided by the pressure equalizing pipe 6 and the exhaust pressure adjusting device 5 provided in the middle thereof.

FIG. 2 is a graph showing the effect of this embodiment. In the figure, A is a curve showing the conventional case, and it is shown that the above-mentioned so-called flow-in situation occurs. In A, it is shown that the cut-out amount of the powdered iron ore and the like far exceeds the set value and falls into uncontrollability. C is a curve showing the case of the present invention. C indicates that the cutout amount of powdered iron ore or the like is controlled to a preset value of 10 ton / hr. On the other hand, B is a situation in which the back pressure is applied in the conventional case. Also in B, it is shown that the cutout amount of the powdered iron ore or the like does not reach the set value and falls out of control.

Further, in FIG. 1, the pressure difference between the pressure P1 on the downstream side of the L valve 7 and the pressure P3 of the freeboard portion 9 is adjusted by the exhaust pressure adjusting device 5 or the like. Even if a fixed orifice is provided in place of the exhaust pressure adjusting device 5 and the like configured by the above, some effects can be obtained. The diameter of the orifice is determined from the amount of gas and the differential pressure assumed in advance. In this case, it is not possible to cope with large fluctuations in the operating condition, but it is effective in controlling the stable cut-out amount of the L valve 7 with respect to a certain degree of differential pressure fluctuation.

In this embodiment, the present invention is applied to control the amount of powdered iron ore or the like cut out from the preliminary reduction furnace of the smelting reduction equipment. It goes without saying that it is also effective when applying powdery ore or the like from the bubbling fluidized bed to control the stable cutting amount.

[0025]

As described above, according to the present invention,
It is possible to prevent a pressure difference between the pressure on the upstream side and the pressure on the downstream side of the L valve for cutting out the granular material. As a result, it is possible to control the stable extraction of powdered ore or the like from the preliminary reduction furnace of the smelting reduction equipment.

[Brief description of drawings]

FIG. 1 is a vertical sectional view showing a configuration of the present invention.

FIG. 2 is a graph showing the effect of the embodiment of the present invention in comparison with a conventional example.

FIG. 3 is an explanatory view showing a conventional smelting reduction equipment.

FIG. 4 is an explanatory view showing a conventional preliminary reduction furnace.

FIG. 5 is a vertical sectional view in the vicinity of a conventional L valve.

[Explanation of symbols]

 2 Coarse iron ore extraction port 3 Stand pipe 4 Coarse ore extraction tank 5 Exhaust pressure adjusting device 6 Pressure equalizing pipe 7 L valve 8 Compressed air piping 9 Freeboard part 10 L valve upstream pressure equalizing pipe end 11 L valve downstream pressure equalizing pipe Edge 12 Pressure sensor in air box 13 Freeboard pressure sensor 14 Reducing gas flow rate / thermometer 15 Control unit 22 L valve horizontal pipe 23 Aeration device 30 Dust remover 31 Melt reduction furnace 32 Pre-reduction furnace 33 Dispersion plate nozzle 34 Dispersion plate 35 Preliminary reduction chamber 36 Air box 37 Fluidized bed

Claims (1)

[Claims] 1. An L-valve type powder and granular material cutting and transferring device comprising a stand pipe, a horizontal pipe connected to the lower end of the stand pipe, and a gas blowing device under the stand pipe, wherein the front and rear of the L valve are connected. A powder and granular material slicing transfer device, characterized in that a pressure equalizing pipe is provided, and an exhaust pressure adjusting device is provided on the pressure equalizing pipe.