JPH0326608A - Powder pressurizing and supplying device - Google Patents

Abstract

PURPOSE:To enable supply stop of fine powder coal supplying device for a jet floor-gasifying furnace by providing a radial passage formed from the center portion of a rotor and a radial passage formed at the final end, which is open to the peripheral edge of the rotor via an axial passage, to supply powder to the center portion via a valve. CONSTITUTION:High-pressure jet is run from a jet nozzle 12 to deliver powder to a high-pressure area 10 in a casing 9. In the meantime, the pressure of a space portion 17 is higher than that of the high-pressure area 10 and gas flows into the high-pressure area 10 via a labyrinth seal 28 to prevent the leakage of fine powder. Then, a volume jetted from a nozzle 12 is controlled, allowing the flow rate of the powder to be controlled and its supply to be stopped.

Description

[Detailed Description of the Invention] [Industrial Application Field] The present invention relates to a pulverized coal supply device for an entrained bed gasifier, a coal supply device for a fluidized bed gasifier, and a coal and limestone supply device for a pressurized fluidized bed boiler. This invention relates to a powder pressurization supply device for supplying powder to a coal supply device to a blast furnace and other high-pressure devices.

[Conventional technology]

Conventionally, a lock hopper system is generally used as a pressurized powder supply device. This consists of a three-stage hopper and is reliable in operation; however, ■ it is high in cost, ■ it consumes a large amount of gas, ■ the residence time in the hopper is long, and there is a risk of spontaneous combustion with pulverized coal, ■ pressurization. Inert gases such as N2 are used as the gas, and large-capacity ones have drawbacks such as high production costs for this inert gas.

Therefore, various rotary powder bottle pressure supply devices have been proposed that use centrifugal force to compact the powder and supply the powder into a casing under high pressure, but the biggest technical problem with this method is It controls the body's flow rate.

This is because a device with insufficient flow rate control cannot be used as a powder supply device.

To illustrate some of the conventionally proposed devices, first, the overall vertical sectional view is shown in FIG. 5, and the cross sectional view of the rotor (Ol) is shown in FIG. 6. An outlet valve (02) with a spring (03) is installed in the part to reduce the powder compaction pressure caused by centrifugal force and the spring (03).
It is a balance between the power of

Next, Fig. 7 shows the overall longitudinal sectional view, and Fig. 8 shows the control nozzle (
The enlarged sectional view of 06) is provided with a control nozzle (06) that can be throttled at the exit of the passage and a gas supply pipe (07) that merges with the control nozzle (06). The flow rate is controlled by changing the pressure of the working gas to (06).

[Problem to be solved by the invention]

The conventional powder pressurization feeding device has the following problems that need to be solved. What is shown in Figures 5 and 6 is the rotor (01)
If the rotation speed of the outlet valve (02) is constant, the opening degree of the outlet valve (02) will be constant, and the flow rate will also be constant. Therefore, in order to change the flow rate, it is necessary to change the rotation speed of the rotor (01). In addition, since the cross-sectional shape of the passage outlet is ring-shaped, it is easy for powder to block it.

Furthermore, in the devices shown in Figures 7 and 8, the flow rate is controlled by changing the pressure of the working gas, and the flow rate can be controlled even when the rotor rotation speed is constant. Since the opening is constant, the minimum flow rate is determined.
It is not possible to stop the supply of powdered books. Therefore, when stopping powder supply. It is necessary to reduce the pressure inside the casing and stop the rotation of the rotor.

[Means to solve the problem]

In order to solve the above-mentioned conventional problems, the present invention provides second radial passages that communicate with the terminal ends of the passages, opens the terminal ends of the second radial passages at the rotor periphery, and The present invention proposes a pressurized powder supply device characterized in that a powder book is supplied to the central portion and pressurized gas is supplied to the passage in the direction of the rotation axis through a valve.

[For production]

According to the present invention, a part of the powder passage in the rotor faces in the direction of the rotation axis, so that even when the rotor rotates, the powder stops in this passage in the rotation axis direction. In order to transfer this, pressurized gas is supplied to the passage in the direction of the rotation axis. The powder flow rate is controlled by changing the flow rate of pressurized gas. [Embodiment] Fig. 1 is a longitudinal sectional view showing an embodiment of the present invention, Fig. 2 is an overall layout including peripheral equipment, and Fig. 3 is a detailed sectional view of the vicinity of the rotor powder outlet. .

First, in Fig. 2, the powder in the low-pressure powder main hopper (1) is fed in a fixed amount by the feeder (2) to the pneumatic transport device (4) driven by the blower (3), and then the powder is fed into the powder transfer pipe (5). through the central cavity of the rotor (7) of the powder book pressurization supply device {6
》 The rotor (7) is attached to a rotating shaft (to) supported by a bearing (c), and is rotationally driven by a motor (5). The powder sent to the rotor central air clearance section (6) is subjected to centrifugal force by the rotor (7), and
K is centrifuged into a plurality of radial passages (8) provided. In the radial passage (8), the powder is consolidated because it is subjected to even stronger centrifugal force, resulting in a high pressure area Q in the casing (9).
It is pushed out in the circumferential direction against the gas pressure of l. The high pressure air supplied from the compressor α3 through the conduit α4, the control valve α, and the passage αQ causes the powder to be further compressed into the casing (9).
(described in detail later).

The air is then guided to the air transport device and is supplied to a high-pressure device Qυ such as a gasification furnace by pressurized air by the compressor AL. On the other hand, the gas sent along with the powder from the powder transfer pipe (5) to the rotor central cavity (6) is transferred to the rotor (7).
), it is centrifuged and released into the atmosphere via an exhaust pipe, a dust collector, and a vacuum pump.

Next, as shown in Fig. 1 and ta3, the rotor (
At the end of each radial passage (8) provided in
The starting ends of the rotational axis direction passages t11) are connected to each other, and the starting ends of the radial passageways (lla) @2 are connected to the terminal ends of the rotational axis direction passages aυ. The end of the second radial passage (lla) opens at the periphery of the rotor (7). At the starting end of the passage in the direction of the rotational axis, a jet nozzle α opens in the same axial direction. The jet nozzle α communicates with the space a through the passage (I). This space (17) also communicates with the passage (conduit α4 via IG) (IEZ diagram). , (To), @, (7), Cl9 is a labyrinth seal. Now, the powder book pushed out into the radial passage (8) by the centrifugal force of the rotor (7) is as shown in Figure 3. , it stops on the passage side in the direction of the rotational axis when the following conditions are met: 73) D cotθ where l: Length in the direction of the rotational axis D: Height in the radial direction θ: Angle of repose of the powder Angle of repose of the powder Since θ is in the range of 20° to 45°,
cotθ is 2.75 to 1.00. In other words, it is necessary to set l/D to 17'j to 3 depending on the angle of repose of the powder book.If it is less than that, the angle of repose of the powder cannot be maintained and the powder is forced into the second radial passage (lla). Spills out. If l is made more than three times D, the conveyance resistance will increase, pressure loss will increase, and the required flow rate of working gas, which will be described later, will increase. Gas within the high pressure region α value flows back to the center of the rotor (7) through the gap between the compacted powder sheets, but the flow rate is small because the powder books are compacted. If the centrifugal force on the powder is greater than the pressure of the high-pressure gas, the powder will not flow backwards.

Next, in order to transfer the powder in the passage αυ in the rotation axis direction, a high-pressure jet is ejected from the jet nozzle α2, and the powder is sent to a high-pressure region in the casing (9).

The high-pressure gas sent to the jet nozzle cL is pressurized by the compressor α3, and is passed through the conduit (14), the control valve (l!9, the passage aQ in the casing, the space (In) and the rotor (7).
) is supplied to the et nozzle 02 through the passage α in :). In this case, the shorter the passage αυ in the rotational axis direction, the smaller the energy of the high-pressure jet, that is, the smaller the working gas flow rate. Therefore, the rotational axial passage α
The appropriate length of υ is the minimum length that can stop the powder book. Furthermore, if the passage αυ in the direction of the rotational axis is widened toward the outlet as shown in FIG. 3, powder can easily flow out, but the appropriate inclination angle α is in the range of 25° from O0. When the high-pressure jet is ejected as described above,
Since the pressure in the space an is higher than the high pressure region (1G), the gas in the space leaks into the high pressure region αO through the labyrinth seal. Therefore, the fine powder in the high pressure region H flows into the labyrinth seal and into the space. There is no backflow to the outlet.In other words, the gas inside the space is always clean, and problems such as powder clogging the passages (IS, αa) do not occur.In addition, the labyrinth seal (self) seal As a result, the amount of leakage from the space (17) to the high-pressure region αG is small, and the leakage flow rate distribution of the labyrinth seal bracket becomes uniform.

Next, we will explain the control of powder flow rate. The powder flow rate can be controlled by changing the flow rate of the high-pressure jet ejected from the jet nozzle α.

In other words, the higher the working gas flow rate of the high-pressure jet.
The powder flow rate increases. The maximum value of the powder flow rate is determined by the passage area of the radial passage (8).

In this case, the working gas flow rate and powder flow rate should have a linear relationship. Therefore, if the powder flow rate is controlled by changing the working gas flow rate, the control accuracy is low.

Therefore, in order to improve the controllability of the main powder flow rate, the flow rate of the working gas is set to a value that maximizes the main powder flow rate, and the valve α installed in the conduit α4 is opened and closed. Control opening hours.

Here, Tl: Valve opening time T2: Valve closing time Tt=Tx+Tz: Period Q: Powder flow rate Qm: Maximum powder flow rate As can be seen from the above equation, if the period Ti=T1+T2 is constant, the powder flow tQ is There is a linear proportional relationship with the opening time T1. That is, the controllability of the powder flow 1tQ is improved, and the flow rate or pressure of the working gas may be set constant. Therefore, this pigeon joint valve a5 may be a simple opening/closing valve rather than a control valve. Incidentally, the residence time of powder in a practical powder book pressurization supply device is about 2 to 10 seconds, and operation control is facilitated by setting the valve opening/closing period to half that, 1 to 5 seconds.

Next, FIG. 4 shows a diagram of another embodiment of the present invention. It is a detailed sectional view of the vicinity of the Yunokonmoto exit. In this figure, the same parts as those in the first embodiment described in Figure @3 are given the same reference numerals and detailed explanations will be omitted. In Fig. 4, the starting end of the passage αυ in the rotational axis direction, which is connected to the terminal end of the radial passage (8) provided in the rotor (7), opens into the high pressure region α0 through an opening hole (to). There is. The jet nozzle (to) for powder transfer is attached to the casing (9) with the outlet ■■■ facing the opening hole ■. Therefore, the jet ejected from the jet nozzle can transfer the powder in the passage αυ in the direction of the rotational axis to the high pressure part α value. By arranging the plurality of opening holes C33 provided in the rotor (7) all on the same circumference, the jet ejected from one jet nozzle (to) rotates the rotor (7) and all The powder can be transferred through the rotational axial passage αυ.

In this case, the jet injection for each passage a1) in the direction of the rotational axis operates intermittently, and the operating time is determined by the rotational speed of the rotor (7) and the number of passages. Therefore, the powder flow rate is controlled by changing the jet flow rate. If the opening and closing of the valve is synchronized with the rotor rotation speed,
The amount of working gas is saved.

In this example, the jet nozzle (to) is connected to the casing (9).
), the structure is very simple and manufacturing costs are low.

In addition, in this example, the casing (9) and the rotor (7)
Multiple labyrinth seals (to) between each. ■
Furthermore, an opening (to) is provided in the casing (9) of the space (17) between the labyrinth seal (to) and the fence, and the high pressure area is connected from this opening (to) to the space (ID). Gas was blown at a pressure higher than αO.Therefore, it was possible to prevent the fine powder in the casing (9) from flowing back into the labyrinth seal (to) and the space (1?).

〔Effect of the invention〕

(1) In the present invention, a part facing the rotational axis direction is provided at the powder passage outlet of the rotor, and a jet nozzle is placed in that part. Therefore, by changing the gas flow rate of the high-pressure jet, the rotational speed of the rotor can be adjusted. The powder supply amount (flow rate) can be changed without changing the internal pressure. In particular, by stopping the supply of working gas, it is possible to completely stop the powder supply and reduce the flow rate to zero without having to perform operations such as stopping the rotation of the rotor or reducing the gas pressure inside the casing. (2) Furthermore, since the shape of the powder passage is simple and no valves or the like are used, there is no risk of blockage.

(3) Further Vc. Since the means for controlling the powder flow rate is simple, changing the pressure or flow rate of the gas for driving the jet nozzle, failures are rare.

[Brief explanation of drawings]

Fig. 1 is a longitudinal sectional view showing an embodiment of the present invention, Fig. 2 is an overall layout including peripheral equipment, and Fig. 3 is a detailed sectional view of the vicinity of the powder outlet of the rotor. FIG. 4 is a detailed cross-sectional view of the rotor near the powder outlet in another embodiment of the present invention. Fig. 5 is an overall vertical cross-sectional view showing an example of a conventionally proposed powder pressurization supply device, and Fig. 6 is a cross-sectional view showing the rotor of the same example. FIG. 7 is an overall longitudinal sectional view showing another conventional example, and FIG. 8 is an enlarged sectional view showing a nozzle of the same example. (1)...Low pressure powder hopper (2)...Feeder《
3}...Blower (4)...Pneumatic transport device (51...Powder transfer tube (6)...Rotor central cavity (7)...Rotor (8)...Radial passage (9)...Casing α0...High pressure area α9...Rotation axis direction passage (lla)...Second
Radial passage α2...Jet nozzle 0...Co7 Full/tube (141-...Conduit αta...
...Control valve QO...Passage (16a)...Opening aD
...Space α...Passage α...Conzoresor...Pneumatic transport device QI)...High pressure equipment...Exhaust pipe (self)...Dust collector
...Vacuum pump (E)...Rotating shaft (C)...Bearing shaft...Motor @@ (to) Gυ...Labyrinth seal (to)...Opening hole (to)...・Jet nozzle example...Jet nozzle outlet (to)...Opening (Ol)・
...Rotor (o2)...Valve (03)...Spring (07)...Gas supply pipe (06)...Control nozzle substitute entry

Claims (1)

[Claims] A rotary axial passage is communicated with the terminal end of the radial passage extending from the center to the peripheral edge of the rotating rotor, and a second radial passage is communicated with the terminal end of the rotary axial passage, and the second radial passage Powder pressurization characterized in that the end of the passage is opened at the rotor periphery, and powder is supplied to the center of the rotor, and pressurized gas is supplied to the passage in the direction of the rotational axis via a valve. Feeding device.