DESCRIPTION
PULVERIZED COAL CONCENTRATION ADJUSTMENT APPARATUS AND
PULVERIZED COAL COMBUSTION BOILER
Technical Field
The present invention relates to a pulverized coal
concentration adjustment apparatus for adjustment of
pulverized coal supplied to a plurality of pulverized coal
burners mounted to a kiln wall of a pulverized coal combustion
boiler, and a pulverized coal combustion boiler using the
same.
Background Art
As a pulverized coal combustion boiler, in which
pulverized coal pulverized in a coal mill (mill apparatus) is
supplied to a plurality of pulverized coal burners mounted to
a kiln wall and burnt by the pulverized coal burners, one
disclosed in, for example, Patent Citation 1 is known.
Patent Citation 1: Japanese Unexamined Patent
Application, Publication No. 2006-102666
Disclosure of Invention
By the way, in such pulverized coal combustion boiler,
pulverized coal pulverized in a coal mill is pneumatically
conveyed in a pulverized coal pipe. Since pulverized coal is
large in mass as compared with an air and has a tendency of

gravitational sedimentation, pulverized coal flowing in a
lower portion of a pulverized coal pipe in the pulverized coal
pipe is heightened in concentration. Therefore, the
concentration distribution of pulverized coal in a vertical
direction becomes non-uniform at an inlet of a pulverized coal
distributor provided downstream of the pulverized coal pipe,
so that pulverized coal fed to respective pulverized coal
burners through left and right branch pipes from respective
flow passages of the pulverized coal distributor is
distributed differently. In this manner, pulverized coal fed
to the respective pulverized coal burners is distributed
differently whereby there is a fear that a pulverized coal
combustion boiler is made worse (an increase in NOx or
unburned coal) and boiler water tubes become non-uniform in
temperature.
The invention has been thought of in view of the
situation described above and has its object to provide a
pulverized coal concentration adjustment apparatus, which can
achieve an improvement in concentration distribution in a
vertical direction at an inlet of a pulverized coal
distributor and uniformly distribute pulverized coal to
respective pulverized coal burners, and a pulverized coal
combustion boiler.
The invention adopts the following means in order to
solve the problem described above.

A pulverized coal concentration adjustment apparatus
according to the invention comprises a pulverized coal
distributor, of which an upstream end is connected to a
pulverized coal pipe, through which pulverized coal is
pneumatically conveyed to flow, and a downstream end is
connected to a plurality of branch pipes, and which
distributes and pneumatically conveys the pulverized coal to
the respective branch pipes through flow passages in plural
stages, and a gas-particle flow adjustment device provided on
an upstream side of the pulverized coal distributor and at a
bottom in the pulverized coal pipe to adjust pulverized coal
to the branch pipes in concentration, and the gas-particle
flow adjustment device comprises a plate-shaped member
provided along a substantially overall width of the pulverized
coal pipe to have a substantially rectangular shape as viewed
in plan view, a front edge of the gas-particle flow adjustment
device is mounted pivotally to a bottom surface of the
pulverized coal pipe, and an angle formed between an upper
surface of the gas-particle flow adjustment device and a
bottom surface of the pulverized coal pipe can be
automatically adjusted on the basis of signals from flow
sensors mounted to the respective branch pipes.
With the pulverized coal concentration adjustment
apparatus according to the invention, an angle of an upper
surface of the plate-shaped member is automatically adjusted

on the basis of signals from the flow sensors mounted to the
respective branch pipes. Therefore, with the pulverized coal
concentration adjustment apparatus, pulverized coal passing
in, for example, the respective branch pipes can be made
substantially equal (substantially uniform) in concentration
to each other, and pulverized coal fed to the respective
branch pipes positioned downstream of the pulverized coal
distributor and the respective pulverized coal burners can be
uniformly distributed, so that it is possible to improve the
combustion quality (reduction in NOx and unburned coal), thus
enabling making boiler water tube temperatures uniform.
A pulverized coal concentration adjustment apparatus
according to the invention comprises a pulverized coal pipe,
through which pulverized coal is pneumatically conveyed to
flow, and a pulverized coal distributor, of which an upstream
end is connected to the pulverized coal pipe and a downstream
end is connected to a plurality of branch pipes, and which
distributes and pneumatically conveys the pulverized coal to
the respective branch pipes through flow passages in plural
stages, and a downstream end of the pulverized coal pipe is
formed to arrange the pulverized coal distributor in a
location, in which a distance from an elbow portion of the
pulverized coal pipe is equal to or less than 10 times an
inside diameter of the pulverized coal pipe, more preferably,
in that range, in which a distance from the elbow portion of

the pulverized coal pipe is three times to five times the
inside diameter of the pulverized coal pipe.
With the pulverized coal concentration adjustment
apparatus according to the invention, pulverized coal flowing
in a lower portion of the pulverized coal pipe on the upstream
side of the elbow flows along an inner wall surface of the
elbow positioned radially outward to be directed upward from
the lower portion of the pulverized coal pipe while being
acted by a centrifugal force at the elbow. Consequently, the
pulverized coal is rolled upward in the vicinity of an outlet
(that is, in the vicinity of an inlet of the pulverized coal
distributor) of the elbow to flow into the inlet of the
pulverized coal distributor while being scattered upward.
Thereby, pulverized coal fed to the respective branch
pipes positioned downstream of the pulverized coal distributor
and the respective pulverized coal burners can be uniformly
distributed, so that it is possible to improve the combustion
quality (reduction in Nox and unburned coal), thus enabling
making boiler water tube temperatures uniform.
A pulverized coal concentration adjustment apparatus
according to the invention comprises a pulverized coal
distributor, of which an upstream end is connected to a
pulverized coal pipe, through which pulverized coal is
pneumatically conveyed to flow, and a downstream end is
connected to a plurality of branch pipes, and which

distributes and pneumatically conveys the pulverized coal to
the respective branch pipes through flow passages in plural
stages, and a ribbon screw arranged in the pulverized coal
pipe and downstream of an elbow portion of the pulverized coal
pipe to impart a whirling flow to the pulverized coal.
With the pulverized coal concentration adjustment
apparatus according to the invention, pulverized coal flowing
in a lower portion of the pulverized coal pipe on the upstream
side of the elbow flows along an inner wall surface of the
elbow positioned radially outward while being acted by a
centrifugal force at the elbow. Thereafter, the pulverized
coal is given a whirling force (rotating force) when passing
between a surface of the ribbon screw and an inner wall
surface of a pulverized coal pipe positioned downstream of the
elbow, and flows into an inlet of a pulverized coal
distributor while being scattered radially outward.
Thereby, pulverized coal fed to respective branch pipes
positioned downstream of the pulverized coal distributor and
respective pulverized coal burners can be uniformly
distributed, so that it is possible to improve the combustion
quality (reduction in NOx and unburned coal), thus enabling
making boiler water tube temperatures uniform.
A pulverized coal combustion boiler according to the
invention comprises a pulverized coal concentration adjustment
apparatus, which can uniformly distribute pulverized coal,

which is fed to respective branch pipes positioned downstream
of a pulverized coal distributor and respective pulverized
coal burners, so that it is possible to improve the combustion
quality (reduction in NOx and unburned coal), thus enabling
making boiler water tube temperatures uniform.
The invention produces an effect that it is possible to
achieve an improvement in concentration distribution in a
vertical direction at an inlet of a pulverized coal
distributor and to uniformly distribute pulverized coal to
respective pulverized coal burners.
Brief Description of Drawings
[FIG. 1] Fig. 1 is a block diagram showing a whole
outline construction of a pulverized coal combustion boiler
provided with a pulverized coal concentration adjustment
apparatus according to a first embodiment of the invention.
[FIG. 2] Fig. 2 is a cross sectional view taken along the
line A-A in Fig. 1.
[FIG. 3] Fig. 3 is a perspective view showing the
pulverized coal concentration adjustment apparatus, according
to the first embodiment of the invention, as viewed from a
side of a pulverized coal pipe.
[FIG. 4] Fig. 4 is a perspective view showing a
pulverized coal distributor, according to the embodiment, as
viewed from a side of a kiln.
[FIG. 5] Fig. 5 is a view showing a planar arrangement of

a pulverized coal concentration adjustment apparatus according
to a second embodiment of the invention.
[FIG. 6] Fig. 6 is a perspective view showing a
pulverized coal concentration adjustment apparatus, according
to a third embodiment of the invention, as viewed from a
pulverized coal pipe.
Explanation of Reference
1: pulverized coal combustion boiler
13: pulverized coal pipe
13a: pulverized coal pipe
13b: pulverized coal pipe
13c: pulverized coal pipe
13d: pulverized coal pipe
17a: pulverized coal distributor
17b: pulverized coal distributor
17c: pulverized coal distributor
17d: pulverized coal distributor
18a: branch pipe
18b: branch pipe
19: pulverized coal concentration adjustment apparatus
20: kicker block (gas-particle flow adjustment device)
22: flow passage
31: pulverized coal concentration adjustment apparatus
elbow
33a: pulverized coal pipe

33b: pulverized coal pipe
33c: pulverized coal pipe
33d: pulverized coal pipe
34a: branch pipe
34b: branch pipe
41: pulverized coal concentration adjustment apparatus
42: ribbon screw
Best Mode for Carrying Out the Invention
A first embodiment of a pulverized coal concentration
adjustment apparatus according to the invention will be
described below with reference to Figs. 1 to 4.
Fig. 1 is a block diagram showing a whole outline
construction of a pulverized coal combustion boiler provided
with a pulverized coal concentration adjustment apparatus
according to the embodiment, Fig. 2 is a cross sectional view
taken along the line A-A in Fig. 1, Fig. 3 is a perspective
view showing the pulverized coal concentration adjustment
apparatus, according to the embodiment, as viewed from a side
of a pulverized coal pipe, and Fig. 4 is a perspective view
showing a pulverized coal distributor, according to the
embodiment, as viewed from a side of a kiln.
As shown in Fig. 1, a boiler 1 includes a kiln 2 mounted
in a vertical direction, a combustion apparatus 4 mounted in a
lower portion of a kiln wall 3 of the kiln 2, a gas flue 5
connected to an outlet of the kiln 2, a superheater 6 provided

extending from an upper portion of the kiln 2 to the gas flue
5, a reheater 7, a coal economizer 8, and a steam drum 9
provided above the kiln 2.
A multiplicity of water tubes (not shown), respectively,
are provided inside the kiln wall 3 to extend vertically, the
respective water tubes being connected at respective upper and
lower ends thereof to the steam drum 9.
The combustion apparatus 4 includes a plurality of
pulverized coal burner (not shown) mounted to the kiln wall 3,
a pulverized coal supply apparatus 10 for supplying of
pulverized coal to the pulverized coal burners, and an air
supply apparatus 11 for supplying of secondary air as a
combustion air to the pulverized coal burners.
The pulverized coal supply apparatus 10 includes a coal
mill (coal pulverizer) 12 for pulverization of coal, which is
supplied through a coal feeder (not shown) and a measuring
instrument (not shown), to a size (for example, several μm to
several hundreds μm) suited to combustion, and a pulverized
coal pipe (coal feed pipe) 13 for draft conveyance of
pulverized coal, which is generated by the coal mill 12, as a
pulverized coal-air mixture to the pulverized coal burners
with a conveyance air pressurized and fed from an air source.
According to the embodiment, four pulverized coal pipes 13
(pulverized coal 13a, 13b, 13c, 13d) are provided.
Also, the conveyance air is set in terms of safety aspect

of the coal mill 12 so that temperature at the outlet of the
coal mill 12 becomes about 80°C.
The air supply apparatus 11 includes a forced draft
blower (not shown) for pressurization and feeding of an air, a
windbox 14 provided on an outer wall of the kiln 2, and an air
pipe 15 for connection between the forced draft blower and the
windbox 14.
A secondary air passing through the air pipe 15 is caused
by a rotary regenerated heat exchanger 16 to perform heat
exchange with combustion exhaust gases, temperature of which
is, for example, about 360°C and which pass through the gas
flue 5, to be heated to 300°C to 350°C to be fed to the windbox
14.
As shown in Fig. 2, pulverized coal burners #1 to #8 are
mounted to the kiln wall 3 of the pulverized coal combustion
boiler 1. Pulverized coal distributors 17a, 17b, 17c, 17d are
provided one by one for the two pulverized coal burners.
Pulverized coal is pneumatically conveyed through four
pulverized coal pipes 13a, 13b, 13c, 13d to the respective
pulverized coal distributors 17a, 17b, 17c, 17d from the coal
mill 12. Two branch pipes 18a, 18b are connected to the
respective pulverized coal distributors 17a, 17b, 17c, 17d.
Pulverized coal pneumatically conveyed to the respective
pulverized coal distributors 17a, 17b, 17c, 17d is fed to the
respective pulverized coal burners through the branch pipes

18a, 18b provided on the respective pulverized coal
distributors 17a, 17b, 17c, 17d. Also, flow sensors (not
shown) (for example, the powder flowmeter of Promecon Ltd. in
Germany), respectively, are mounted to the branch pipes 18a,
18b to measure the flow rate of pulverized coal passing
therethrough.
A pulverized coal concentration adjustment apparatus 19
according to the embodiment includes the pulverized coal
distributor 17a, 17b, 17c, 17d and a kicker block 20 (see Fig.
3) .
As shown in Figs. 3 and 4, the pulverized coal
distributor 17a, 17b, 17c, 17d are connected to the pulverized
coal pipe 13a, 13b, 13c, 13d, through which pulverized coal is
pneumatically fed to flow in an arrow A direction, and the
branch pipes 18a, 18b, which branch to both left and right
sides in a position downstream of the pulverized coal pipe
13a, 13b, 13c, 13d, respectively. A plurality of partition
plates 21 are provided in the respective pulverized coal
distributors 17a, 17b, 17c, 17d. Interiors of the respective
pulverized coal distributors 17a, 17b, 17c, 17d, respectively,
are partitioned by the partition plates 21 whereby flow
passages 22 in plural stages are formed up and down and left
and right in the respective pulverized coal distributors 17a,
17b, 17c, 17d.
Also, as shown in Fig. 4, blank plates 23 are arranged on

a downstream side of the flow passage 22. According to the
embodiment, the blank plates 23 are arranged alternately on
the left and right of the flow passage 22 in a vertical
direction. The blank plates 23 cut off communication of the
respective flow passages 22 to one of the branch pipes 18a,
18b and flows branched left and right in an arrow B direction
and in an arrow C direction pneumatically convey pulverized
coal into the branch pipes 18a, 18b.
As shown in Fig. 3, the kicker block (gas-particle flow
adjustment device) 20 adjusts the concentration of pulverized
coal toward the both left and right branch pipes 18a, 18b
positioned on a downstream side. The kicker block 20 is
provided in a lower portion of the pulverized coal pipe 13a,
13b, 13c, 13d on an upstream side of inlets of the pulverized
coal distributor 17a to 17d.
The kicker block 20 comprises a plate-shaped member
arranged along a substantially overall width of the pulverized
coal pipe 13a, 13b, 13c, 13d and having a substantially
rectangular shape as viewed in plan view. A front (upstream)
edge of the kicker block 20 is mounted pivotally to a bottom
surface (lower surface) of the pulverized coal pipe 13a, 13b,
13c, 13d. That is, the kicker block 20 is able to swing about
the front edge, at which it is connected to the pulverized
coal pipe 13a, 13b, 13c, 13d, with the front edge as a
fulcrum. The kicker block 20 is formed so that an angle

(angle of inclination) 6 between its upper surface and a
bottom surface (lower surface) of the pulverized coal pipe
13a, 13b, 13c, 13d can be adjusted in the range of, for
example, 0 degree to 60 degrees. The angle 0 can be
automatically adjusted on the basis of signals from the flow
sensors mounted to the respective branch pipes 18a, 18b by a
controller (not shown) so that pulverized coal passing in the
branch pipe 18a and pulverized coal passing in the branch pipe
18b are made substantially equal (substantially uniform) in
concentration (flow rate) to each other.
Also, an abrasion-resistant material 24 such as ceramic
is provided on the upper surface of the kicker block 20 in
order to prevent abrasion caused by the passing pulverized
coal. The abrasion-resistant material 24 is fixed (anchored)
by sticking, for example, a multiplicity of tile pieces, which
are formed to be square-shaped, to the upper surface of the
kicker block 20 with an adhesive or the like.
Subsequently, an explanation will be given to the action
of the pulverized coal concentration adjustment apparatus 19
according to the embodiment.
First, when pulverized coal is fed into the pulverized
coal pipes 13a, 13b, 13c, 13d from the coal mill 12 by means
of pneumatic conveyance, the pulverized coal flows in the
pulverized coal pipes 13a, 13b, 13c, 13d to be directed to the
pulverized coal distributors 17a, 17b, 17c, 17d as indicated

by the arrow A direction in the figure. At this time, the
pulverized coal flows in lower portions of the pulverized coal
pipes 13a, 13b, 13c, 13d due to gravitational sedimentation.
In this manner, the pulverized coal flowing in the lower
portions of the pulverized coal pipes 13a, 13b, 13c, 13d
strikes against the upper surface of the kicker block 20 in
the vicinity of inlets of the pulverized coal distributors
17a, 17b, 17c, 17d to be rolled upward to flow into the inlets
of the pulverized coal distributors 17a, 17b, 17c, 17d while
being scattered upward. The pulverized coal as scattered
upward is divided (distributed) into the arrow B direction or
into the arrow C direction by the pulverized coal distributors
17a, 17b, 17c, 17d and then flows in the downstream branch
pipes 18a, 18b to be fed to the pulverized coal burners
mounted to the kiln wall 3 to be burnt by the pulverized coal
burners.
With the pulverized coal concentration adjustment
apparatus 19 according to the embodiment, an angle 0 of the
upper surface of the kicker block 20 is automatically adjusted
on the basis of signals from the flow sensors mounted to the
respective branch pipes 18a, 18b. Thereby, pulverized coal
passing in the branch pipe 18a and pulverized coal passing in
the branch pipe 18b are made substantially egual
(substantially uniform) in concentration to each other, that
is, pulverized coal fed to the left and right branch pipes

18a, 18b positioned downstream of the pulverized coal
distributor 17a, 17b, 17c, 17d and the respective pulverized
coal burners can be uniformly distributed, so that it is
possible to reduce NOx and unburned coal.
Also, since the abrasion-resistant material 24 is
provided on the upper surface of the kicker block 20, it is
possible to improve the kicker block 20 in durability.
A second embodiment of a pulverized coal concentration
adjustment apparatus according to the invention will be
described with reference to Fig. 5. Fig. 5 is a view showing
a planar arrangement of the pulverized coal concentration
adjustment apparatus according to the embodiment.
The pulverized coal concentration adjustment apparatus 31
according to the embodiment is different from that of the
first embodiment in that instead of the kicker block 20 a
pulverized coal pipe 33a, 33b, 33c, 33d is provided to arrange
each of pulverized coal distributors 17a, 17b, 17c, 17d in a
location 10D (D is an inside diameter of the pulverized coal
pipe) distant from an elbow (bent portion) 32 of the
pulverized coal pipe, more preferably, in the range of 3D to
5D from the elbow 32 of the pulverized coal pipe. Other
constituent elements are the same as those of the first
embodiment and so an explanation therefor is omitted herein.
In addition, the same members as those of the first
embodiment are denoted by the same reference numerals as those

of the latter.
As shown in Fig. 5, according to the embodiment, each of
the pulverized coal distributor 17a, 17b, 17c, 17d is mounted
in a location, in which a horizontal distance (shortest
distance) L between a rear end thereof (that is, a portion
jointed to branch pipes 34a, 34b) and a central axis CL of the
pulverized coal pipe 33a, 33b, 33c, 33d positioned in the
vicinity of and on an upstream side of the elbow 32 is equal
to or less than 10D (D is an inside diameter of the pulverized
coal pipe 33a, 33b, 33c, 33d), more preferably, corresponds to
3D to 5D.
With the pulverized coal concentration adjustment
apparatus 31 according to the embodiment, pulverized coal
flowing in a lower portion of the pulverized coal pipe 33a,
33b, 33c, 33d on the upstream side of the elbow 32 flows along
an inner wall surface of the elbow 32 positioned radially
outward to be directed upward from the lower portion of the
pulverized coal pipe 33a, 33b, 33c, 33d while being acted by a
centrifugal force at the elbow 32. Consequently, the
pulverized coal is rolled upward in the vicinity of an outlet
(that is, in the vicinity of an inlet of the pulverized coal
distributor 17a, 17b, 17c, 17d) of the elbow 32 to flow into
the inlet of the pulverized coal distributor 17a, 17b, 17c,
17d while being scattered upward.
Thereby, pulverized coal fed to the left and right branch

pipes 34a, 34b positioned downstream of the pulverized coal
distributor 17a, 17b, 17c, 17d and the respective pulverized
coal burners can be uniformly distributed, so that it is
possible to improve the combustion quality (reduction in NOx
and unburned coal), thus enabling making boiler water tube
temperatures uniform. In addition, the embodiment adopts the
branch pipes 34a, 34b, of which pipe length is lengthened
corresponding to an extent, by which the pulverized coal
distributor 17a, 17b, 17c, 17d is mounted close to the elbow
32 of the pulverized coal pipe 33a, 33b, 33c, 33d. When such
branch pipes 34a, 34b are adopted, however, pulverized coal
distributed uniformly passes in the branch pipes 34a, 34b, so
that such adoption of the branch pipes 34a, 34b does not
affect uniformization of distribution of the pulverized coal.
A third embodiment of a pulverized coal concentration
adjustment apparatus according to the invention will be
described with reference to Fig. 6. Fig. 6 is a perspective
view showing the pulverized coal concentration adjustment
apparatus, according to the embodiment, as viewed from a
pulverized coal pipe.
The pulverized coal concentration adjustment apparatus 41
according to the embodiment is different from that of the
first embodiment in that a ribbon screw 42 is provided instead
of the kicker block 20. Other constituent elements are the
same as those of the first embodiment and so an explanation

therefor is omitted herein.
In addition, the same members as those of the first
embodiment and the second embodiment are denoted by the same
reference numerals as those of the latter.
As shown in Fig. 6, the ribbon screw 42 is a thin plate
member, which divides a flow passage in a pulverized coal pipe
33a, 33b, 33c, 33d into two halves so as to make flow passage
areas thereof substantially equal to each other. The ribbon
screw 42 is arranged so as to have one end (upstream end)
thereof positioned in the vicinity of an outlet of an elbow 32
and to have the other end (downstream end) thereof positioned
in the vicinity of an inlet of a pulverized coal distributor
17a, 17b, 17c, 17d. Also, one end and the other end of the
ribbon screw 42, respectively, are arranged to agree
substantially with a perpendicular (vertical) axis, which
passes a central axis of the pulverized coal pipe 33a, 33b,
33c, 33d. The ribbon screw 42 is twisted to lead pulverized
coal, which flows along an inner wall surface of the elbow 32
positioned radially outward in the elbow 32, upwardly of the
pulverized coal pipe 33a, 33b, 33c, 33d to lead the same to
one side (leftward as viewed from an upstream side) of the
pulverized coal pipe 33a, 33b, 33c, 33d.
With the pulverized coal concentration adjustment
apparatus 41 according to the embodiment, pulverized coal
flowing in a lower portion of the pulverized coal pipe 13a,

13b, 13c, 13d on the upstream side of the elbow 32 flows along
an inner wall surface of the elbow 32 positioned radially
outward while being acted by a centrifugal force at the elbow
32. Thereafter, the pulverized coal is given a whirling force
(counter-clockwise torque as viewed from the upstream side)
when passing between a surface 42a of the ribbon screw 42 and
an inner wall surface of a pulverized coal pipe 13a, 13b, 13c,
13d positioned downstream of the elbow 32, and flows into the
inlet of a pulverized coal distributor 17a, 17b, 17c, 17d
while being scattered radially outward.
Thereby, pulverized coal fed to left and right branch
pipes 18a, 18b positioned downstream of the pulverized coal
distributor 17a, 17b, 17c, 17d and respective pulverized coal
burners can be uniformly distributed, so that it is possible
to improve the combustion quality (reduction in NOx and
unburned coal), thus enabling making boiler water tube
temperatures uniform.
In addition, the invention is not limited to the
embodiments described above but can be changed, modified, and
embodied within a scope not departing from the gist of the
invention. For example, the kicker block 20 described in the
first embodiment is also applicable to the second embodiment
or the third embodiment.
Also, the embodiments have been described with respect to
an arrangement, in which the two branch pipes 18a, 18b, 34a,

34b are connected to the downstream side of the pulverized
coal distributor 17a, 17b, 17c, 17d. However, the invention
is not limited thereto but applicable to that arrangement, in
which three or more branch pipes are connected to the
downstream side of the pulverized coal distributor 17a, 17b,
17c, 17d.

CLAIMS
1. A pulverized coal concentration adjustment apparatus
comprising
a pulverized coal distributor, of which an upstream end
is connected to a pulverized coal pipe, through which
pulverized coal is pneumatically conveyed to flow, and a
downstream end is connected to a plurality of branch pipes,
and which distributes and pneumatically conveys the pulverized
coal to the respective branch pipes through flow passages in
plural stages, and
a gas-particle flow adjustment device provided on an
upstream side of the pulverized coal distributor and at a
bottom in the pulverized coal pipe to adjust pulverized coal
to the branch pipes in concentration, and
wherein the gas-particle flow adjustment device comprises
a plate-shaped member provided along a substantially overall
width of the pulverized coal pipe to have a substantially
rectangular shape as viewed in plan view, a front edge of the
gas-particle flow adjustment device is mounted pivotally to a
bottom surface of the pulverized coal pipe, and an angle
formed between an upper surface of the gas-particle flow
adjustment device and a bottom surface of the pulverized coal
pipe can be automatically adjusted on the basis of signals
from flow sensors mounted to the respective branch pipes.
2. A pulverized coal concentration adjustment apparatus

comprising
a pulverized coal pipe, through which pulverized coal is
pneumatically conveyed to flow, and
a pulverized coal distributor, of which an upstream end
is connected to the pulverized coal pipe and a downstream end
is connected to a plurality of branch pipes, and which
distributes and pneumatically conveys the pulverized coal to
the respective branch pipes through flow passages in plural
stages, and
wherein a downstream end of the pulverized coal pipe is
formed to arrange the pulverized coal distributor in a
location, in which a distance from an elbow portion of the
pulverized coal pipe is equal to or less than 10 times an
inside diameter of the pulverized coal pipe.
3. The pulverized coal concentration adjustment apparatus
according to claim 2, wherein the downstream end of the
pulverized coal pipe is formed to arrange the pulverized coal
distributor in that range, in which a distance from the elbow
portion of the pulverized coal pipe is three times to five
times the inside diameter of the pulverized coal pipe.
4. A pulverized coal concentration adjustment apparatus
comprising
a pulverized coal distributor, of which an upstream end
is connected to a pulverized coal pipe, through which
pulverized coal is pneumatically conveyed to flow, and a

downstream end is connected to a plurality of branch pipes,
and which distributes and pneumatically conveys the pulverized
coal to the respective branch pipes through flow passages in
plural stages, and
a ribbon screw arranged in the pulverized coal pipe and
downstream of an elbow portion of the pulverized coal pipe to
impart a whirling flow to the pulverized coal.
5. A pulverized coal combustion boiler comprising the
pulverized coal concentration adjustment apparatus according
to any one of claims 1 to 4.

To achieve an improvement in concentration distribution
in a vertical direction at an inlet of a pulverized coal
distributor and uniformly distribute pulverized coal to
respective pulverized coal burners. A pulverized coal
distributor (17a to 17d) and a gas-particle flow adjustment
device (20) provided on an upstream side of the pulverized
coal distributor (17a to 17d) and at a bottom in a pulverized
coal pipe (13a to 13d) to adjust pulverized coal to branch
pipes (18a, 18b) in concentration are provided, the gas-
particle flow adjustment device (20) comprises a plate-shaped
member provided along a substantially overall width of the
pulverized coal pipe (13a to 13d) to have a substantially
rectangular shape as viewed in plan view, a front edge of the
gas-particle flow adjustment device is mounted pivotally to a
bottom surface of the pulverized coal pipe (13a to 13d), and
an angle formed between an upper surface of the gas-particle
flow adjustment device and a bottom surface of the pulverized
coal pipe (13a to 13d) can be automatically adjusted on the
basis of signals from flow sensors mounted to the respective
branch pipes (18a, 18b).