Field of the Invention
[0001] The invention relates to a technology of a pulverized coal burning device, in particular
to a dense/dilute pulverized coal separator structure of an anthracite burning single-fireball
octagonal direct-flow burner.
Description of the Related Art
[0002] About 640 billion tons of coal reserves have been proven in China, among which low
volatile anthracite accounts for about 14.6% of total coal reserves. Anthracite consumption
of domestic thermal power plants accounts for about 3% of total coal consumption for
power generation, and the figure is increasing. Anthracite has low volatile content,
low hydrogen content, high ignition temperature and slower flame propagation velocity.
In case of improper organization of burning, instable burning at low load and easy
flameout of boilers at high load in case of poor coal quality easily occur, and burning
efficiency is generally lower.
[0003] At present, W flame boilers, quadrangular tangentially fired boilers and front and
rear wall swirl opposed firing boilers are used for burning anthracite at home and
abroad. The maximum capacity of each W flame boiler is 600MW, the maximum capacity
of each quadrangular tangentially fired boiler and front and rear wall swirl opposed
firing boiler is 300MW respectively, and design and operation performance of any quadrangular
tangentially anthracite firing boiler of 600MW and above are unavailable.
[0004] Domestic power station boiler manufactures have begun to design and manufacture special
anthracite firing boilers since the early 1970s. With the development of unit capacity
to 600MW - 1300MW, significant changes occur to furnace thermal parameters of boilers
compared with 125MW and 300MW anthracite firing boilers, and reduction of furnace
volume heat release rate q
v and extended retention time of pulverized coal in furnaces are favorable for complete
burning of anthracite. Meanwhile, furnace wall heat release rate q
Hr of the burner area is reduced, although cross section heat release rate q
F is increased, total heat absorption of the burner area is increased, resulting in
reduction of temperature of the burner area, thus being unfavorable for timely and
stable ignition of anthracite. Especially after the capacity is increased to 800MW
- 1300MW, the number of corresponding pulverized coal nozzles of a single coal mill
has to be increased by 50% - 100% compared with 300MW - 600MW boilers, i.e. from 4
to 6 or 8, due to restriction from thermal power of a single pulverized coal nozzle.
A 1000MW ultra supercritical boiler is taken for example, when 6 medium speed coal
mills or double inlet and double outlet coal mills are equipped, the number of corresponding
pulverized coal nozzles of a single coal mill is 8, and the number of total pulverized
coal nozzles reaches 48. When quadrangular tangential arrangement of a direct flow
burner is employed, the number of primary air pulverized coal nozzles at a single
corner is 12, and burners are divided into 2 to 3 groups in the vertical direction,
as a result, the distance between two primary air pulverized coal nozzles arranged
at the uppermost part and the lowermost part is large, the furnace wall heat release
rate q
Hr of the burner area is low, and burning temperature of the area is low, thus being
unfavorable for timely and stable ignition of pulverized anthracite air flow and stable
burning of the boiler at low load without oil.
[0005] Almost all 50MW, 125MW and 300MW anthracite firing boilers which have been successfully
put into operation in China use intermediate storage hot air pulverized coal feed
systems, primary air and pulverized coal mixing temperature of the systems can reach
220 - 250°C, with primary air ratio of 14 - 15%, and exhaust air containing moisture
can be separated from the primary air and fed into furnaces from upper parts of burners,
thus reducing ignition heat of pulverized coal, and the use of the intermediate storage
hot air pulverized coal feed systems is the key to successfully burning anthracite
in 50 - 300MW boilers. However, with regard to an intermediate storage hot air pulverized
coal feed system, as the maximum power output of domestic steel ball mills is about
50t/h, each furnace in units of 600MW and above has to be provided with 6 - 8 mills,
the system itself is complex, and the pulverized coal bunker is huge, it is difficult
for the design institute to design and arrange the system, and the system covers a
larger area. Therefore, after the unit capacity is increased to 600MW, the system
is not recommended generally.
[0006] As shown in Figure 1 and Figure 2, a 1000MW ultra supercritical boiler is taken for
example to illustrate tangential arrangement of an existing burner. Figure 2 is an
II- II sectional view of Figure 1, and Figure 1 is an I-I sectional view of Figure
2. The arrangement comprises a boiler body 1, a furnace 2, coal mills 3, pulverized
coal pipes 4, primary air pulverized coal nozzles 5 and secondary air nozzles 6. Each
boiler 1 is provided with 6 coal mills 3 with number of A, B, C, D, E and F respectively.
The furnace 2 consists of four water cooled walls 7, a burner group 8 is arranged
at each corner of the furnace 2, and center lines of nozzles of the quadrangular nozzles
8 form an imaginary tangent circle in the furnace 2. Each burner group 8 is divided
into three burner subgroups along the vertical direction at a certain interval; each
burner subgroup consists of four primary air pulverized coal nozzles 5 and six secondary
air nozzles 6, that is, 12 primary air pulverized coal nozzles 5 and 18 secondary
air nozzles 6 are arranged along the vertical direction at an interval, for example,
12 primary air pulverized coal nozzles 5 at No. I corner are numbered with A1-1, A1-2,
B1-1, B1-2, C1-1, C1-2, D1-1, D1-2, E1-1, E1-2, F1-1, F1-2, and 12 primary air pulverized
coal nozzles 5 at No. 4 corner are numbered with A4-1, A4-2, B4-1, B4-2, C4-1, C4-2,
D4-1, D4-2, E4-1, E4-2, F4-1, F4-2. Coal mills 3 are connected with the primary air
pulverized coal nozzles 5 through the pulverized coal pipes 4, four pulverized coal
pipes 4 are arranged at an outlet of each coal mill 3, each pulverized coal pipe 4
is connected with 2 primary air pulverized coal nozzles 5 with similar elevation at
the same corner through a pulverized coal distributor 10, for example, coal mill 3
numbered A is connected with eight primary air pulverized coal nozzles 5 numbered
A1-1, A1-2, A2-1, A2-2, A3-1, A3-2, A4-1, A4-2. It can be seen that as each burner
group 8 is provided with 12 primary air pulverized coal nozzles 5 along the vertical
direction at a certain interval, furnace wall heat release rate q
Hr of the burner area is lower in the arrangement, thus being unable to meet the requirements
for burning anthracite.
Summary of the Invention
[0007] The invention provides a dense/dilute pulverized coal separator structure of a single-fireball
octagonal direct-flow burner, thus generating higher furnace wall heat release rate
q
Hr of the burner area.
[0008] In order to realize the purpose, the invention provides a dense/dilute pulverized
coal separator structure of a single-fireball octagonal direct-flow burner, comprising:
a boiler body surrounded by four water cooled walls, wherein an inner space formed
by the four water cooled walls is a furnace of the boiler body;
multiple burners which are arranged on the water cooled walls respectively and communicated
with the furnace through the water cooled walls, and on which nozzles, toward inside
of the furnace are arranged;
pulverized coal pipelines;
a dense/dilute pulverized coal separator which is connected with the multiple burners
respectively by the pulverized coal pipelines; and
multiple coal mills which are connected with the dense/dilute pulverized coal separator
by the pulverized coal pipelines;
each of the boiler body being provided with at least one of the coal mills;
and characterized in that the boiler body is provided with eight burner groups, each
of the water cooled walls is provided with two burner groups respectively, each burner
group comprises multiple nozzles toward the same burner, and center lines of all nozzles
on the eight burner groups form an imaginary tangent circle in the furnace.
[0009] The four water cooled walls of the boiler body are respectively arranged as a front
wall, a rear wall, a left wall and a right wall of the boiler body, the front wall
is arranged opposite to the rear wall, and the left wall is arranged opposite to the
right wall; center line of the nozzle of the burner arranged on the front wall or
the rear wall intersects with the water cooled wall at which the burner is located
at an intersection point, distance between the intersection point and a joint with
the nearest adjacent water cooled wall is L1, 1/10Lw≤L1≤4/10Lw, and Lw is distance
between the front wall and the rear wall of the boiler body.
[0010] Center line of the nozzle of the burner arranged on the left wall or the right wall
intersects with the water cooled wall at which the burner is located at an intersection
point, distance between the intersection point and a joint with the nearest adjacent
water cooled wall is L2, 1/10Ld≤L2≤4/10Ld, and Ld is distance between the left wall
and the right wall of the boiler body.
[0011] The center line of the nozzle of the burner intersects with the water cooled wall
at which the burner is located at an intersection point, the intersection point and
center of the imaginary tangent circle form a straight line, and an included angle
a is arranged between the straight line and the center line of the nozzle of the burner,
0°≤a≤30°.
[0012] Each of the burner group
s is divided into two subgroups along the vertical direction, and the two subgroups
are a first burner subgroup arranged at a lower part of the water cooled walls and
a second burner subgroup arranged at an upper part of the water cooled walls respectively.
[0013] The first burner subgroup comprises a primary air/pulverized rich coal burner on
which at least one primary air/pulverized rich coal nozzle and two secondary air nozzles
are arranged along the vertical direction, and the primary air/pulverized rich coal
nozzle and the secondary air nozzles are arranged at an interval.
[0014] The second burner subgroup comprises a primary air/pulverized lean coal burner on
which at least one primary air/pulverized lean coal nozzle and two secondary air nozzles
are arranged along the vertical direction, and the primary air/pulverized lean coal
nozzle and the secondary air nozzles are arranged at an interval.
[0015] An outlet of each of the coal mills is connected with multiple pulverized coal pipelines,
and each of the pulverized coal pipelines is divided into a pulverized rich coal pipeline
and a pulverized lean coal pipeline by the dense/dilute pulverized coal separator.
[0016] The pulverized rich coal pipeline is provided with a pulverized coal distributor
and divided into multiple thin pulverized rich coal pipelines by the pulverized coal
distributor, and the multiple thin pulverized rich coal pipelines are connected with
the multiple primary air/pulverized rich coal nozzles respectively.
[0017] The pulverized lean coal pipeline is provided with a pulverized coal distributor
and divided into multiple thin pulverized lean coal pipelines by the pulverized coal
distributor, and the multiple thin pulverized lean coal pipelines are connected with
the multiple primary air/pulverized lean coal nozzles respectively.
[0018] Distance between the primary air/pulverized lean coal nozzle arranged at the uppermost
part and the primary air/pulverized rich coal nozzle arranged at the lowermost part
is between 1m and 2m.
[0019] Compared with the prior art, the dense/dilute pulverized coal separator structure
of a single-fireball octagonal direct-flow burner of the invention has the following
advantages:
- 1. In the invention, the arrangement of connecting pulverized coal air flow at the
outlet of each coal mill with 8 rich primary air/pulverized coal nozzles and 8 lean
primary air/pulverized coal nozzles at the same level helps is characterized by increasing
pulverized coal concentration of the pulverized rich coal area while meeting thermal
power of the whole boiler, allowing furnace wall heat release rate qHr of a lower
burner area to be higher, allowing burning temperature of the area to meet requirements
for anthracite burning stability, and ensuring timely ignition of pulverized anthracite
air flow and stable burning of the boiler at low load without oil.
- 2. Compared with an arrangement of four burner groups at four corners, arrangement
of eight burner groups on the four water cooled walls of the boiler is characterized
by providing better air supply conditions at both sides of jet flow, being less susceptible
to occurrence of wall sticking of primary air pulverized coal, being favorable for
preventing slagging and high temperature corrosion of the furnace, and improving adaptability
to coal variety.
- 3. Compared with an arrangement of four burner groups at four corners, arrangement
of eight burner groups on the four water cooled walls of the boiler is characterized
by shortening distance of jet flow from a nozzle outlet to downstream adjacent air
flow, being capable of using lower primary pulverized coal air flow velocity, being
favorable for timely ignition of pulverized anthracite air flow and stable burning
of the boiler at low load without oil, being capable of reducing secondary air velocity,
and being favorable for reducing residual swirl strength of fireball and differential
temperature of smoke at the furnace outlet.
- 4. Compared with an arrangement of four burner groups at four corners, arrangement
of eight burner groups on the four water cooled walls of the boiler body is characterized
by enhancing heat flow strength at the nozzle outlets, greatly improving convection
and radiation heat transfer capacity, and being favorable for timely ignition of pulverized
anthracite air flow and stable burning of the boiler at low load without oil.
- 5. Distance between the primary air/pulverized lean coal nozzle arranged at the uppermost
part and the primary air/pulverized rich coal nozzle arranged at the lowermost part
is controlled between 1m and 2m, thus reducing total height of the boiler, greatly
reducing manufacturing cost of the boiler, and reducing emission of nitrogen oxides
from the boiler while meeting distance between the primary air pulverized coal nozzle
arranged at the uppermost part and bottom of the furnace outlet and anthracite burning
efficiency.
Brief Description of the Drawing
[0020]
Figure 1 is a schematic diagram of burner arrangement of the prior art, and an I-I
sectional view of Figure 2;
Figure 2 is a schematic diagram of burner arrangement of the prior art, and an II-II
sectional view of Figure 1;
Figure 3 is a structural diagram of a medium speed coal mill or double inlet and double
outlet direct-fired pulverizing system with a dense/dilute pulverized coal separator
of the dense/dilute pulverized coal separator structure of a single-fireball octagonal
direct-flow burner of the invention;
Figure 4 is a schematic diagram of the dense/dilute pulverized coal separator structure
of a single-fireball octagonal direct-flow burner of the invention, and an I-I sectional
view of Figure 5; and
Figure 5 is a schematic diagram of the dense/dilute pulverized coal separator structure
of a single-tireball octagonal direct-flow burner of the invention, and an II-II sectional
view of Figure 4.
Description of the Preferred Embodiment
[0021] The preferred embodiments of the invention will be described in combination with
accompanying drawings.
[0022] As shown in Figure 4, in an embodiment of the disclosed dense/dilute pulverized coal
separator structure of an anthracite burning single-fireball octagonal direct-flow
burner, each boiler comprises a boiler body 1 which comprises four water cooled walls
9, and the four water cooled walls 9 surround and form the boiler body 1, and an inner
space formed by the four water cooled walls is a furnace 2 of the boiler body 1. The
furnace 2 is Ld in depth and Lw in width. Each boiler body 1 is provided with eight
burner groups which are arranged on four water cooled walls 9 of the boiler body 1
respectively, each water cooled wall is provided with two burner groups, and each
burner group comprises multiple vertically arranged burners 10. The eight burner groups
are arranged circularly by centering on center of the furnace 2, and angle spacing
between two burner groups is the same. Each burner 10 is provided with nozzles, in
the same burner group, the direction of nozzles of the burner 10 is the same, nozzles
of burners 10 in the eight burner groups are arranged toward inside of the furnace
2, center lines of all nozzles in the eight burner groups (i.e., jet directions of
all nozzles in the eight burner groups) form an imaginary tangent circle 11 in a counterclockwise
direction in the furnace 2 (in counterclockwise direction in overlook), and the center
of the imaginary tangent circle 11 coincides with the center of the furnace 2.
[0023] Center line of the nozzle of each burner 10 intersects with a corresponding water
cooled wall 9 of the burner 10 at an intersection point, the intersection point and
the center of the imaginary tangent circle 11 form a straight line, and an included
angle a is formed between the straight line and the center line of the nozzle of the
burner 10, with value range of 0°≤a≤30°. In the embodiment, the included angle a is
4°, i.e. a=4°.
[0024] Among four water cooled walls 9 of the boiler body 1, two opposite water cooled walls
9 are a front wall and a rear wall of the boiler body 1, and the other two wall cooled
walls 9 are a left wall and a right of the boiler body 1, distance between the front
wall and the rear wall of the boiler body 1 is depth Ld of the furnace 2, and distance
between the left wall and the right wall of the boiler body 1 is width Lw of the furnace
2.
[0025] Center line of the nozzle of the burner 10 arranged on the front wall or the rear
wall of the boiler body 1 intersects with the water cooled wall 9 at which the burner
10 is located at an intersection point, and distance between the intersection point
and an edge (joint between two adjacent water cooled walls 9 is at the edge) of the
nearest furnace 2 is L1, with value range of 1/10Lw≤L1≤4/10 Lw. In the embodiment,
L1 is a quarter of the width Lw of the furnace 2, i.e., L1=1/4Lw.
[0026] Similarly, center line of the nozzle of the burner 10 respectively arranged on the
left wall and the right wall of the boiler body 1 intersects with the water cooled
wall 9 at which the burner 10 is located at an intersection point, and distance between
the intersection point and an edge (joint between two adjacent water cooled walls
9 is at the edge) of the nearest furnace 2 is L2, with value range of 1/10Ld≤L2≤4/10Ld.
In the embodiment, L2 is a quarter of the depth Ld of the furnace 2, i.e., L2=1/4Ld.
[0027] As shown in Figure 5 in combination with Figure 4, each burner group is divided into
two subgroups along the vertical direction, and the two subgroups are a first burner
subgroup arranged at a lower side wall of the boiler body I and a second burner subgroup
arranged at an upper side wall of the boiler body 1.
[0028] Burners 10 in the first burner subgroup are primary air/pulverized rich coal burners
which are provided with nozzles, the nozzles are arranged toward inside of the furnace
according to the structure, and communicated with inside of the furnace. The nozzles
arranged on the primary air/pulverized rich coal burners comprises six primary air/pulverized
rich coal nozzles 6 and seven secondary air nozzles 8, the primary air/pulverized
rich coal nozzles 6 are arranged between two adjacent secondary air nozzles 8 at an
interval.
[0029] All secondary air nozzles 8 are connected with a large secondary air bellow through
pipelines, and the large secondary air bellow is connected with an external secondary
air pipeline. In order to ensure safe burning, secondary air is fed into the boiler
through the secondary air nozzles 8.
[0030] The twelve primary air/pulverized rich coal nozzles 6 on the primary air/pulverized
rich coal burners of the two burner groups arranged on the front wall are numbered
with A1-1-1, A1-1-2, B1-1-1, B1-1-2, C1-1-1, C1-1-2, D1-1-1, D1-1-2, E1-1-1, E1-1-2,
F1-1-1, F1-1-2 respectively. The twelve primary air/pulverized rich coal nozzles 6
on the primary air/pulverized rich coal burners of the two burner groups arranged
on the rear wall are numbered with A3-1-1, A3-1-2, B3-1-1, B3-1-2, C3-1-1, C3-1-2,
D3-1-1, D3-1-2, E3-1-1, E3-1-2, F3-1-1, F3-1-2 respectively. The twelve primary air/pulverized
rich coal nozzles 6 on the primary air/pulverized rich coal burners of the two burner
groups arranged on the left wall are numbered with A2-1-1, A2-1-2, B2-1-1, B2-1-2,
C2-1-1, C2-1-2, D2-1-1, D2-1-2, E2-1-1, E2-1-2, F2-1-1, F2-1-2 respectively. The twelve
primary air/pulverized rich coal nozzles 6 on the primary air/pulverized rich coal
burners of the two burner groups arranged on the right wall are numbered with A4-1-1,
A4-1-2, B4-1-1, B4-1-2, C4-1-1, C4-1-2, D4-1-1, D4-1-2, E4-1-1, E4-1-2, F4-1-1, F4-1-2
respectively.
[0031] The primary air/pulverized rich coal nozzles 6 numbered A1-1-1, A1-1-2, A3-1-1, A3-1-2,
A2-1-1, A2-1-2, A4-1-1, A4-1-2 are correspondingly arranged on the same level as nozzles
of the same level. The primary air/pulverized rich coal nozzles 6 numbered B1-1-1,
B1-1-2, B3-1-1, B3-1-2, B2-1-1, B2-1-2, B4-1-1, B4-1-2 are correspondingly arranged
on the same level as nozzles of the same level. The primary air/pulverized rich coal
nozzles 6 numbered C1-1-1, C1-1-2, C3-1-1, C3-1-2, C2-1-1, C2-1-2, C4-1-1, C4-1-2
are correspondingly arranged on the same level as nozzles of the same level. The primary
air/pulverized rich coal nozzles 6 numbered D1-1-1, D1-1-2, D3-1-1, D3-1-2, D2-1-1,
D2-1-2, D4-1-1, D4-1-2 are correspondingly arranged on the same level as nozzles of
the same level. The primary air/pulverized rich coal nozzles 6 numbered E1-1-1, E1-1-2,
E3-1-1, E3-1-2, E2-1-1, E2-1-2, E4-1-1, E4-1-2 are correspondingly arranged on the
same level as nozzles of the same level. The primary air/pulverized rich coal nozzles
6 numbered F1-1-1, F1-1-2, F3-1-1, F3-1-2, F2-1-1, F2-1-2, F4-1-1, F4-1-2 are correspondingly
arranged on the same level as nozzles of the same level.
[0032] Burners 10 in the second burner subgroup are primary air/pulverized lean coal burners
which are provided with nozzles, the nozzles are arranged toward inside of the furnace
according to the structure, and communicated with inside of the furnace. The nozzles
arranged on the primary air/pulverized lean coal burners comprises six primary air/pulverized
lean coal nozzles 7 and seven secondary air nozzles 8, the primary air/pulverized
lean coal nozzles 7 are arranged between two adjacent secondary air nozzles 8 at an
interval.
[0033] All secondary air nozzles 8 are connected with a large secondary air bellow through
pipelines, and the large secondary air bellow is connected with an external secondary
air pipeline. In order to ensure safe burning, secondary air is fed into the boiler
through the secondary air nozzles 8.
[0034] The twelve primary air/pulverized lean coal nozzles 7 on the primary air/pulverized
lean coal burners of the two burner groups arranged on the front wall are numbered
with A1-2-1, A1-2-2, B1-2-1, B1-2-2, C1-2-1, C1-2-2, D1-2-1, D1-2-2, E1-2-1, E1-2-2,
F1-2-1, F1-2-2 respectively. The twelve primary air/pulverized lean coal nozzles 7
on the primary air/pulverized lean coal burners of the two burner groups arranged
on the rear wall are numbered with A3-2-1, A3-2-2, B3-2-1, B3-2-2, C3-2-1, C3-2-2,
D3-2-1, D3-2-2, E3-2-1, E3-2-2, F3-2-1, F3-2-2 respectively. The twelve primary air/pulverized
lean coal nozzles 7 on the primary air/pulverized lean coal burners of the two burner
groups arranged on the left wall are numbered with A2-2-1, A2-2-2, B2-2-1, B2-2-2,
C2-2-1, C2-2-2, D2-2-1, D2-2-2, E2-2-1, E2-2-2, F2-2-1, F2-2-2 respectively. The twelve
primary air/pulverized lean coal nozzles 7 on the primary air/pulverized lean coal
burners of the two burner groups arranged on the right wall are numbered with A4-2-1,
A4-2-2, B4-2-1, B4-2-2, C4-2-1, C4-2-2, D4-2-1, D4-2-2, E4-2-1, E4-2-2, F4-2-1, F4-2-2
respectively.
[0035] The primary air/pulverized lean coal nozzles 7 numbered A1-2-1, A1-2-2, A3-2-1, A3-2-2,
A2-2-1, A2-2-2, A4-2-1, A4-2-2 are correspondingly arranged on the same level as nozzles
of the same level. The primary air/pulverized lean coal nozzles 7 numbered B1-1-1,
B1-1-2, B3-1-1, B3-1-2, B2-1-1, B2-1-2, B4-1-1, B4-1-2 are correspondingly arranged
on the same level as nozzles of the same level. The primary air/pulverized lean coal
nozzles 7 numbered C1-1-1, C1-1-2, C3-1-1, C3-1-2, C2-1-1, C2-1-2, C4-1-1, C4-1-2
are correspondingly arranged on the same level as nozzles of the same level. The primary
air/pulverized lean coal nozzles 7 numbered D1-1-1, D1-1-2, D3-1-1, D3-1-2, D2-1-1,
D2-1-2, D4-1-1, D4-1-2 are correspondingly arranged on the same level as nozzles of
the same level. The primary air/pulverized lean coal nozzles 7 numbered E-1-1, E1-1-2,
E3-1-1, E3-1-2, E2-1-1, E2-1-2, E4-1-1, E4-1-2 are correspondingly arranged on the
same level as nozzles of the same level. The primary air/pulverized lean coal nozzles
7 numbered F1-1-1, F1-1-2, F3-1-1, F3-1-2, F2-1-1, F2-1-2, F4-1-1, F4-1-2 are correspondingly
arranged on the same level as nozzles of the same level.
[0036] In each burner group, the distance between the primary air/pulverized lean coal nozzle
7 arranged at the uppermost part and the primary air/pulverized rich coal nozzle 6
arranged at the lowermost part is between 1m and 2m, thus reducing total height of
the boiler, greatly reducing manufacturing cost of the boiler, and reducing emission
of nitrogen oxides from the boiler while meeting distance between the primary air
pulverized coal nozzle arranged at the uppermost part and bottom of the furnace outlet
and anthracite burning efficiency.
[0037] Each boiler is provided with six coal mills 3, i.e. a first coal mill A, a second
coal mill B, a third coal mill C, a fourth coal mill D, a fifth coal mill E and a
sixth coal mill F.
[0038] An outlet of each coal mill 3 is connected with four pulverized coal pipelines 5,
each pulverized coal pipeline 5 is provided with a dense/dilute pulverized coal separator
4, and the dense/dilute pulverized coal separator 4 divides each pulverized coal pipeline
5 into a pulverized rich coal pipeline and a pulverized lean coal pipeline.
[0039] Each pulverized rich coal pipeline is also provided with a pulverized coal distributor
12 which divides the pulverized rich coal pipeline into two thin pulverized rich coal
pipelines which are respectively connected with the primary air/pulverized rich coal
nozzles 6 of respective primary air/pulverized rich coal burners in the two burner
groups arranged on the same water cooled wall 9.
[0040] Each coal mill 3 is connected with the primary air/pulverized rich coal nozzles 6
as follows:
The first coal mill A is respectively connected with the primary air/pulverized rich
coal nozzles 6 numbered A1-1-1, A1-1-2, A2-1-1, A2-1-2, A3-1-1, A3-1-2, A4-1-1, A4-1-2.
The second coal mill B is respectively connected with the primary air/pulverized rich
coal nozzles 6 numbered B1-1-1, B1-1-2, B2-1-1, B2-1-2, B3-1-1, B3-1-2, B4-1-1, B4-1-2.
The third coal mill C is respectively connected with the primary air/pulverized rich
coal nozzles 6 numbered C1-1-1, C1-1-2, C2-1-1, C2-1-2, C3-1-1, C3-1-2, C4-1-1, C4-1-2.
The fourth coal mill D is respectively connected with the primary air/pulverized rich
coal nozzles 6 numbered D1-1-1, D1-1-2, D2-1-1, D2-1-2, D3-1-1, D3-1-2, D4-1-1, D4-1-2.
The fifth coal mill E is respectively connected with the primary air/pulverized rich
coal nozzles 6 numbered E1-1-1, E1-1-2, E2-1-1, E2-1-2, E3-1-1, E3-1-2, E4-1-1, E4-1-2.
The sixth coal mill F is respectively connected with the primary air/pulverized rich
coal nozzles 6 numbered F1-1-1, F1-1-2, F2-1-1, F2-1-2, F3-1-1, F3-1-2, F4-1-1, F4-1-2.
[0041] Each pulverized lean coal pipeline is provided with a pulverized coal distributor
12 which divides the pulverized lean coal pipeline into two thin pulverized lean coal
pipelines which are respectively connected with the primary air/pulverized lean coal
nozzles 7 of respective primary air/pulverized lean coal burners in the two burner
groups arranged on the same water cooled wall 9.
[0042] Each coal mill 3 is connected with the primary air/pulverized lean coal nozzles 7
as follows:
The first coal mill A is respectively connected with the primary air/pulverized lean
coal nozzles 7 numbered A1-2-1, A1-2-2, A2-2-1, A2-2-2, A3-2-1, A3-2-2, A4-2-1, A4-2-2.
The second coal mill B is respectively connected with the primary air/pulverized lean
coal nozzles 7 numbered B1-2-1, B1-2-2, B2-2-1, B2-2-2, B3-2-1, B3-2-2, B4-2-1, B4-2-2.
The third coal mill C is respectively connected with the primary air/pulverized lean
coal nozzles 7 numbered C1-2-1, C1-2-2, C2-2-1, C2-2-2, C3-2-1, C3-2-2, C4-2-1, C4-2-2.
The fourth coal mill D is respectively connected with the primary air/pulverized lean
coal nozzles 7 numbered D1-2-1, D1-2-2, D2-2-1, D2-2-2, D3-2-1, D3-2-2, D4-2-1, D4-2-2.
The fifth coal mill E is respectively connected with the primary air/pulverized lean
coal nozzles 7 numbered E-2-1, E1-2-2, E2-2-1, E2-2-2, E3-2-1, E3-2-2, E4-2-1, E4-2-2.
The sixth coal mill F is respectively connected with the primary air/pulverized lean
coal nozzles 7 numbered F-2-1, F1-2-2, F2-2-1, F2-2-2, F3-2-1, F3-2-2, F4-2-1, F4-2-2.
[0043] As shown in Figure 3 in combination with Figure 5, the dense/dilute pulverized coal
separator structure of an anthracite burning single-fireball octagonal direct-flow
burner of the invention uses a "medium speed coal mill or double inlet and double
outlet direct-fired pulverizing system with a dense/dilute pulverized coal separator",
the main principle of the structure is to add a dense/dilute pulverized coal separator
4 on each pulverized coal pipeline 5 connected to an outlet of each coal mill 3 so
as to separate and divide rich/lean primary air/pulverized coal into an air flow containing
80% pulverized coal and 50% primary air/pulverized rich coal, and an air flow containing
remaining 20% pulverized coal and 50% primary air/pulverized lean coal, and the two
air flows are fed into the furnace 2 for burning respectively through primary air/pulverized
rich coal nozzles 6 and primary air/pulverized lean coal nozzles 7 in the burner groups.
The area in the corresponding furnace 2 of the primary air/pulverized rich coal nozzles
6 is a pulverized rich coal burning area, the area in the corresponding furnace 2
of the primary air/pulverized lean coal nozzles 7 is a pulverized lean coal burning
area, and the pulverized lean coal burning area is located above the pulverized rich
coal burning area.
[0044] The use of the "medium speed coal mill or double inlet and double outlet direct-fired
pulverizing system with a dense/dilute pulverized coal separator" enables air-pulverized
coal ratio and primary air ratio of rich primary air/pulverized coal to be superior
to corresponding parameters of intermediate storage hot air pulverized coal feed systems,
meanwhile, 50% primary air containing 50% moisture is separated and fed into the furnace
2 from the primary air/pulverized lean coal nozzles 7 located at the upper parts in
the burner groups. Although the primary air and pulverized coal mixing temperature
is lower than that of boilers using intermediate storage hot air pulverized coal feed
systems, in such design, it can be seen from theoretical calculation that ignition
heat of pulverized rich coal air flow is basically the same as that of boilers using
intermediate storage hot air pulverized coal feed systems, thus ensuring stable ignition
of pulverized rich coal air flow.
[0045] While the invention has been described in detail and with reference to the preferred
embodiment, it is to be understood that the invention is not restricted thereto. It
is apparent to those skilled in the art that various changes and modifications can
be made therein in accordance with the disclosure. Therefore, scope of the invention
is to be restricted only by the appended claims.
1. A dense/dilute pulverized coal separator structure of a single-fireball octagonal
direct-flow burner, comprising:
a boiler body (1) surrounded by four water cooled walls (9), wherein an inner space
formed by the four water cooled walls (9) is a furnace (2) of the boiler body (1);
multiple burners (10) which are arranged on the water cooled walls (9) respectively
and communicated with the furnace (2) through the water cooled walls (9), and on which
nozzles toward an inside of the furnace (2) are arranged;
pulverized coal pipelines (5);
a dense/dilute pulverized coal separator (4) which are connected with the multiple
burners (10) respectively by the pulverized coal pipelines (5); and
multiple coal mills (3) which are connected with the dense/dilute pulverized coal
separator (4) by the pulverized coal pipelines (5);
each of the boiler body (1) being associated with at least one of the coal mills (3);
and characterized in that the boiler body (1) is provided with eight burner groups, each of the water cooled
walls (9) is provided with two burner groups respectively, each burner group comprises
multiple nozzles from the same burner (10), and center lines of all nozzles on the
eight burner groups form an imaginary tangent circle (11) in the furnace (2).
2. The dense/dilute pulverized coal separator structure of a single-fireball octagonal
direct-flow burner according to claim 1, characterized in that the four water cooled walls (9) of the boiler body (1) are respectively arranged
as a front wall, a rear wall, a left wall and a right wall of the boiler body (1),
the front wall is arranged opposite to the rear wall, and the left wall is arranged
opposite to the right wall; center line of the nozzle of the burner (10) arranged
on the front wall or the rear wall intersects with the water cooled wall (9) at which
the nozzle is located at an intersection point, distance between the intersection
point and a joint with the nearest adjacent water cooled wall (9) is L1, where 1/10Lw≤L1≤4/10Lw,
and Lw is distance between the front wall and the rear wall of the boiler body (1).
3. The dense/dilute pulverized coal separator structure of a single-fireball octagonal
direct-flow burner according to claim 2, characterized in that the center line of the nozzle of the burner (10) arranged on the left wall or the
right wall intersects with the water cooled wall (9) at which the nozzle is located
at an intersection point, distance between the intersection point and a joint with
the nearest adjacent water cooled wall (9) is L2, where 1/10Ld≤L2≤4/10Ld, and Ld is
distance between the left wall and the right wall of the boiler body (1).
4. The dense/dilute pulverized coal separator structure of a single-fireball octagonal
direct-flow burner according to claim 1, characterized in that the center line of the nozzle of the burner (10) intersects with the water cooled
wall (9) at which the nozzle is located at an intersection point, the intersection
point and center of the imaginary tangent circle (11) form a straight line, and an
included angle a is arranged between the straight line and the center line of the
nozzle of the burner (10), where 0°≤a≤30°.
5. The dense/dilute pulverized coal separator structure of a single-fireball octagonal
direct-flow burner according to claim 1, characterized in that each of the burner groups is divided into two subgroups along the vertical direction,
and the two subgroups are a first burner subgroup arranged at a lower part of the
water cooled walls (9) and a second burner subgroup arranged at an upper part of the
water cooled walls (9) respectively.
6. The dense/dilute pulverized coal separator structure of a single-fireball octagonal
direct-flow burner according to claim 5, characterized in that the first burner subgroup comprises a primary air/pulverized rich coal burner on
which at least one primary air/pulverized rich coal nozzle (6) and two secondary air
nozzles (8) are arranged along the vertical direction, and the primary air/pulverized
rich coal nozzle (6) and the secondary air nozzles (8) are arranged at an interval.
7. The dense/dilute pulverized coal separator structure of a single-fireball octagonal
direct-flow burner according to claim 6, characterized in that the second burner subgroup comprises a primary air/pulverized lean coal burner on
which at least one primary air/pulverized lean coal nozzle (7) and two secondary air
nozzles (8) are arranged along the vertical direction, and the primary air/pulverized
lean coal nozzle (7) and the secondary air nozzles (8) are arranged at an interval.
8. The dense/dilute pulverized coal separator structure of a single-fireball octagonal
direct-flow burner according to claim 7, characterized in that an outlet of each of the coal mills (3) is connected with multiple pulverized coal
pipelines (5), and each of the pulverized coal pipeline (5) is divided into a pulverized
rich coal pipeline and a pulverized lean coal pipeline by the dense/dilute pulverized
coal separator (4).
9. The dense/dilute pulverized coal separator structure of a single-fireball octagonal
direct-flow burner according to claim 8, characterized in that the pulverized rich coal pipeline is provided with a pulverized coal distributor
(12) and divided into multiple thin pulverized rich coal pipelines by the pulverized
coal distributor (12), and the multiple thin pulverized rich coal pipelines are connected
with the multiple primary air/pulverized rich coal nozzles (6) respectively;
the pulverized lean coal pipeline is provided with a pulverized coal distributor (12)
and divided into multiple thin pulverized lean coal pipelines by the pulverized coal
distributor (12), and the multiple thin pulverized lean coal pipelines are connected
with the multiple primary air/pulverized lean coal nozzles (7) respectively.
10. The dense/dilute pulverized coal separator structure of a single-fireball octagonal
direct-flow burner according to claim 7, characterized in that distance between the primary air/pulverized lean coal nozzle (7) arranged at the
uppermost part and the primary air/pulverized rich coal nozzle (6) arranged at the
lowermost part is between 1m and 2m.