JPH05246550A - Fine particle storing device - Google Patents

Abstract

PURPOSE:To store pulverized coal in a hopper in a state that coarse pulverized coal collected by a cyclone is not separated away from pulverized coal collected by a bag filter, uniform specific gravity is provided, and a fine particle pressure at the outlet of a hopper is well balanced. CONSTITUTION:Coarse pulverized coal 2a in coal 2 crushed by a crusher 1 is collected by a cyclone 3 and charged in a storage hopper 5 through a pipe 4. Meanwhile, pulverized coal 2b in the crushed coal 2 is collected by a bag filter 6 and charged in the storage hopper 5 through a pipe 7. In this case, the charge opening ends 4a and 7a of the coarse pulverized coal charge pipe 4 and the pulverized coal charge pipe 7 are concentrically arranged in a state that the former is situated at the outside and the latter at the inside, and connected to the central part of the upper part of the storage hopper 5. This constitution causes the pulverized coal 2b dropped from the inside to drop in a mixed state while being wrapped with the coarse pulverized coal 2a dropping in an annular shape from the outside and effects accumulation in such a way that the center of the hopper 5 forms the apex of the angle of repose.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a powder storage device used in fluidized bed boilers, coal fired boilers, gasification furnaces and the like.

[0002]

2. Description of the Related Art As an example of prior art, FIG. 3 shows a conventional powder storage device used in a fluidized bed boiler using coal as a fuel. Since the fluidized bed boiler burns coal while fluidizing fluid material (limestone, sand, etc.) having a particle size of about 1 to 5 mm on the perforated plate, the particle size of the coal is about the same as that of the fluid material. Those with a distribution are good. However, when the coal is actually crushed by a crusher, the coal has a wide particle size distribution of several μ to 4/5 mm. Therefore, conventionally, a cyclone that collects coal having a large amount of coarse particles and a bag filter that collects coal having a large amount of fine powder have been generally used.

That is, referring to FIG. 3, the coal 2 crushed by the crusher 1 is conveyed by air flow into the cyclone 3, and the cyclone 3 separates and collects the coarse coal 2a of comparatively large particles from the air flow. Collected, charged into the storage hopper 5 through the coarse powder charging pipe 4 which is a cyclone outlet pipe, and stored. In this cyclone 3, 80 to 90% of coal is recovered. Then, the pulverized coal 2b that has not been collected by the cyclone 3 is conveyed by air to the bag filter 6 installed in the downstream of the cyclone 3, and after this bag filter 6 collects and collects all the pulverized coal 2b. Then, it is put into the storage hopper 5 through the fine powder feeding pipe 7 which is the bag filter outlet pipe and stored.

The coarse coal 2a and the fine coal 2b thus stored in the storage hopper 5 are then stored in the storage hopper 5.
By rotating the mastic type constant quantity feeder 8 provided in the lower center of the electric motor 9 with the electric motor 9, it is supplied to a fluidized bed boiler (not shown) and burned.

[0005]

In the above-mentioned conventional example, however, the coarse powder charging pipe 4 for charging the coarse coal 2a collected by the cyclone 3 into the storage hopper 5 and the bag filter 6 are used. The charging opening ends 4a and 7a of the pulverized coal feeding pipe 7 for charging the pulverized coal 2b into the storage hopper 5 are separated from each other and connected to the upper portion (upper lid) of the storage hopper 5, and the pulverized coal 2
The a and the pulverized coal 2b are naturally fallen into the storage hopper 5 separately and accumulated.

For this reason, as shown in FIG.
In the storage hopper 5, a portion containing a large amount of coarse coal 2a and a fine coal 2b
Will be mixed with the part with many. In addition, since the recovery rate of the cyclone 3 is high, the amount of deposition in the lower portion of the coarse powder feeding pipe 4 is large, and it can be offset in the storage hopper 5. That is, the crushed coal 2 (2
a, 2b) will be mixed, and more and more type constant quantity feeder 8
Even if the supply is carried out at a constant rotation speed, the supply amount (weight supply amount / unit time) is not constant. Therefore, it becomes impossible to maintain the combustion state under a certain condition in the fluidized bed, and in extreme cases, it may become impossible to maintain the combustion due to the abnormal rise or fall of the temperature in the fluidized bed.

The present invention has been made in order to solve the problems of the prior art as described above, and the coarse powder collected by the cyclone and the fine powder collected by the bag filter have a uniform bulk density without being separated. An object of the present invention is to provide a powder storage device which has the powder pressure at the outlet of the hopper and can store the powder pressure in the hopper without imbalance.

[0008]

In order to solve the above-mentioned problems, the present invention provides a coarse powder feeding pipe for feeding the coarse powder collected by the cyclone into a storage hopper, and a bag installed downstream of the cyclone. In a powder storage device comprising a fine powder charging pipe for charging the fine powder collected by a filter into the storage hopper, the charging opening end of the coarse powder charging pipe and the charging opening end of the fine powder charging pipe are outside the former. And the latter are arranged concentrically so that they are on the inside, and are connected to the upper center of the storage hopper.

[0009]

According to the above-mentioned means, the coarse powder collected by the cyclone and the fine powder collected by the bag filter are arranged such that the charging opening ends of the charging tubes are concentric.
Fine powder falling from the inside is mixed and dropped while being wrapped in coarse powder falling from the outside in a ring shape, and accumulated in the storage hopper.

Further, in this case, since these charging opening ends are connected to the upper center of the storage hopper, the mixed powder of the coarse powder and the fine powder is deposited with the center of the storage hopper as the apex of the repose angle. As a result, the powder pressure at the outlet of the hopper is not unbalanced, so that the coarse powder and the fine powder are not separated, and the bulk density can be stored without imbalance.

[0011]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of the present invention will be described in detail below with reference to FIGS. This embodiment is also an example applied to a powder storage device used in a fluidized bed boiler using coal as a fuel, as in FIG. 3, and FIG. 1 is a cross-sectional view showing the powder storage device according to this embodiment. 2 is a sectional view taken along the line II-II in FIG. 1. The same parts as those shown in FIG. 3 are designated by the same reference numerals, and the duplicate description will be omitted.

As shown in FIGS. 1 and 2, according to the present embodiment, the charging opening end 4a of the coarse powder charging pipe 4 for charging the coarse coal 2a collected by the cyclone 3 into the storage hopper 5 and the bag. The pulverized coal 2b collected by the filter 6 is introduced into the storage hopper 5 in a concentric manner with the charging opening end 7a of the pulverized charging tube 7 such that the former is on the outside and the latter is on the inside. Is attached to the upper center of the.

According to such a structure, the pulverized coal 2a collected by the cyclone 3 and the pulverized coal 2b collected by the bag filter 6 are connected to the charging opening ends 4a of the charging pipes 4 and 7. 7a and 7a are concentrically arranged, the pulverized coal 2b falling from the inside is mixed and dropped while being wrapped in the pulverized coal 2a falling from the outside, and accumulated in the storage hopper 5.

Then, in this case, these input opening ends 4
Since a and 7a are connected to the upper center of the storage hopper 5, the mixed pulverized coal 2c of the pulverized coal 2a and the pulverized coal 2b is shown in FIG.
As shown in FIG. 5, the center of the storage hopper 5 is deposited as the apex of the angle of repose, thereby eliminating the imbalance of the powder pressure at the outlet of the hopper, and thus the coarse coal 2a and the fine coal 2
It is stored without being separated from b and without imbalance in bulk specific gravity.

The mixed pulverized coal 2c of the pulverized coal 2a and the pulverized coal 2b thus stored in the hopper 5 is then
It is supplied to a fluidized-bed boiler (not shown) in a fixed amount by an increasing type constant amount feeder 8 provided in the lower center of the storage hopper 5,
To burn. In this case, since the bulk specific gravity of the mixed pulverized coal 2c is always constant, the supply amount (weight supply amount / unit time) does not fluctuate even if the constant type quantitative feeder 8 is constantly rotated by the electric motor 9 and is stable in the fluidized bed. Combustion is obtained. According to the experimental results, it was confirmed that the fluctuation of the residual O ₂ concentration in the combustion exhaust gas was reduced to about 1/2 of the conventional value.

The above-described embodiment is an example in which the present invention is applied to a powder storage device used in a fluidized bed boiler using coal as a fuel, but the present invention is not limited to this, and the present invention is a coal-fired boiler and gasification. Needless to say, the same can be applied to a powder storage device used in a furnace or the like.

[0017]

As described above, according to the present invention, the charging opening end of the coarse powder charging pipe for charging the coarse powder collected by the cyclone to the storage hopper and the fine powder collected by the bag filter are stored in the storage hopper. The charging opening end of the fine powder charging pipe to be charged into is arranged concentrically so that the former is the outer side and the latter is the inner side, and the structure is such that it is connected to the center of the upper part of the storage hopper, and the coarse powder and the fine powder are Can be stored in the storage hopper with a uniform bulk density, and a stable supply can be achieved.
Moreover, since there is no imbalance in the powder pressure at the outlet of the storage hopper, it is possible to prevent the powder from bridging at the outlet of the hopper.

[Brief description of drawings]

FIG. 1 is a cross-sectional view showing a powder storage device according to an embodiment of the present invention.

FIG. 2 is a sectional view taken along line II-II in FIG.

FIG. 3 is a cross-sectional view showing a conventional powder storage device.

[Explanation of symbols]

 1 Crusher 2 Crushed coal 2a Coarse coal 2b Pulverized coal 2c Mixed pulverized coal 3 Cyclone 4 Coarse powder input pipe 4a Coarse powder input pipe input opening end 5 Storage hopper 6 Bag filter 7 Fine powder input pipe 7a Fine powder input pipe input opening end 8 Constant supply device 9 Electric motor

Claims (1)

[Claims] 1. A coarse powder charging pipe for charging coarse powder collected by a cyclone into a storage hopper, and a fine powder charging pipe for charging fine powder collected by a bag filter installed downstream of the cyclone into the storage hopper. In the powder storage device comprising
The charging opening end of the coarse powder charging pipe and the charging opening end of the fine powder charging pipe are concentrically arranged so that the former is on the outside and the latter is on the inside, and is connected to the upper center of the storage hopper. Powder storage device.