U.S. patent application number 12/151747 was filed with the patent office on 2008-11-20 for pulverized coal combination burner.
This patent application is currently assigned to Siemens Aktiengesellschaft. Invention is credited to Christian Reuther, Manfred Schingnitz.
Application Number | 20080282945 12/151747 |
Document ID | / |
Family ID | 39829337 |
Filed Date | 2008-11-20 |
United States Patent
Application |
20080282945 |
Kind Code |
A1 |
Reuther; Christian ; et
al. |
November 20, 2008 |
Pulverized coal combination burner
Abstract
Disclosed is a burner for oxidant gasification of pulverized
fuels under high pressures of e.g. 80 bar (8 MPa) and temperatures
of e.g. 1200 to 1900.degree. C. in reactors with liquid slag
removal for oxygen gasification, the individual pulverized fuel
supply tubes in the burner are designed such that, while retaining
the entry cross-sectional area of the tube, the cross-section makes
a systematic transition to a curved rectangular duct matched to the
annulus. This means that fuel feeding ends immediately adjacent to
the oxidant duct, and the flow rate provided in the feeding element
is maintained up to the outlet, thereby ensuring trouble-free flow
of the pulverized fuel and reducing the amount of inert gas
required for purging the feeding element in the non-operational
state.
Inventors: |
Reuther; Christian;
(Freiberg, DE) ; Schingnitz; Manfred; (Freiberg,
DE) |
Correspondence
Address: |
SIEMENS CORPORATION;INTELLECTUAL PROPERTY DEPARTMENT
170 WOOD AVENUE SOUTH
ISELIN
NJ
08830
US
|
Assignee: |
Siemens Aktiengesellschaft
|
Family ID: |
39829337 |
Appl. No.: |
12/151747 |
Filed: |
May 8, 2008 |
Current U.S.
Class: |
110/261 |
Current CPC
Class: |
F23D 1/00 20130101; F23D
17/005 20130101 |
Class at
Publication: |
110/261 |
International
Class: |
F23C 1/10 20060101
F23C001/10 |
Foreign Application Data
Date |
Code |
Application Number |
May 10, 2007 |
DE |
10 2007 021 924.7 |
Claims
1-5. (canceled)
6. A burner for oxidant gasification of pulverized fuels,
comprising a centrally arranged pilot burner section; an annular
duct that supplies the oxidant arranged coaxially with the
centrally arranged pilot burner section; an annulus concentrically
arranged around the annular duct that incorporates a plurality of
pulverized fuel feeding elements, wherein the individual pulverized
fuel feeding elements, while retaining the entry cross-sectional
area of the tube, the cross-section makes a systematic transition
to a curved, equiareal rectangular duct matched to the annulus.
7. The burner as claimed in claim 6, wherein the rectangular width
of the rectangular duct is not less than 25 mm.
8. The burner as claimed in claim 7, wherein the ratio of the
rectangular width to the rectangular length is approximately
1:5.3.
9. The burner as claimed in claim 8, wherein the unnecessary spaces
remaining between the rectangular outlets are sealed off directly
at the outlet and incorporated in the cooling circuit.
10. The burner as claimed in claim 9, wherein the extension rays of
the walls of the annulus intersect the central axis in a direction
of the burner mouth.
11. The burner as claimed in claim 10, wherein the pulverized fuel
is at a pressure of 80 bar.
12. The burner as claimed in claim 11, wherein the pulverized fuel
is at a temperature between 1200.degree. C. to 1900.degree. C.
13. The burner as claimed in claim 12, wherein the burner comprises
a water cooled housing.
14. The burner as claimed in claim 13, wherein the burner further
comprises a high-voltage ignition device.
15. The burner as claimed in claim 14, wherein the burner further
comprises an integrated flame monitoring device.
Description
CROSS REFERENCE TO RELATED APPLICATIONS
[0001] This application claims the benefits of German application
No. 10 2007 021 924.7 filed May 10, 2007 and is incorporated by
reference herein in its entirety.
FIELD OF INVENTION
[0002] The invention relates to a pulverized coal combination
burner which is used for oxygen gasification of pulverized fuels
(brown coals and/or hard coals or similar pulverized fuels) under
high pressures and temperatures in reactors with liquid slag
removal.
[0003] The subject matter of the application relates to a burner
for oxidant gasification of pulverized fuels.
BACKGROUND OF THE INVENTION
[0004] Pulverized coal combination burners for partial oxidation of
pulverized fuels, comprising a cylindrical water-cooled housing and
internal coaxially disposed annuli for supplying the pulverized
fuel and oxidant, are well known.
[0005] Located in the center of the burner is another small
gas/oxygen burner which serves as an igniter or pilot burner and is
equipped with an optical flame monitoring device and a high-voltage
ignition device. It is used for starting up the abovementioned
pulverized coal burner, as disclosed in documents DE 271038 A3 and
DE 4306980 C2.
[0006] Outside and inside the burner, the pulverized fuel is
supplied through one or more tubes. Inside the burner, the supply
tube(s) is(are) run to the burner outlet such that they perform at
least one full rotation about the axis and then end set
tangentially adjacent to the burner outlet. At the end of the
pulverized fuel tube(s) the pulverized fuel dust enters a
cylindrical annulus in a tangential manner.
[0007] At the transition from the tube surface area to the annulus
there is an abrupt increase in area and therefore a reduction in
the pulverized fuel dust velocity. Although increasing the number
of pulverized fuel tubes inside the annulus can reduce the areal
discontinuity, it cannot eliminate it. This results in an uneven
distribution of the pulverized fuel stream inside the annulus,
which can cause asymmetrical flame spread with unilateral stressing
of the reaction chamber.
[0008] The known burner has the following disadvantages:
[0009] 1. complicated design of the tubes inside the cylindrical
annulus in the burner
[0010] 2. after the pulverized coal dust outlet there is an
unavoidable areal discontinuity, thereby reducing the dust
velocity.
[0011] 3. this areal discontinuity causes the downstream annulus to
be unevenly filled with pulverized coal dust, resulting in
differential mixing with the oxidant.
SUMMARY OF INVENTION
[0012] The object of the invention is to create a pulverized coal
burner which operates reliably at pressure under pulverized coal
gasification conditions. The pulverized coal combination burner
shall be designed to ensure reliable operation with uniform flame
spread, even for pressurized gasification of pulverized
products.
[0013] This object is achieved in the case of the subject matter
outlined by the features of the preamble in that the individual
pulverized fuel feeding elements in the burner are implemented such
that there is a systematic (continuous in the direction of flow)
transition of the cross-section to a curved, equiareal rectangular
duct (6) matched to the annulus, while retaining the essentially
circular entry cross-sectional area of the tube.
[0014] By means of this inventive embodiment of the feeding
elements for the pulverized fuels, it is achieved that fuel feeding
ends directly adjacent to the oxidant duct and the flow rate
provided in the feeding element is maintained up to the outlet.
This measure ensures trouble-free conveying of the pulverized fuel
and reduces the amount of inert gas necessary for purging the
feeding element in the nonoperational state.
[0015] Advantageous developments of the subject matter of the
application are detailed in the dependent claims.
BRIEF DESCRIPTION OF THE DRAWINGS
[0016] The subject matter of the application is explained in
greater detail below as an exemplary embodiment to the extent
required for understanding and with reference to the accompanying
drawings, in which:
[0017] FIG. 1 shows a basic cross-section through the inventive
compact burner, and
[0018] FIG. 2 shows a basic longitudinal section through the
inventive compact burner.
[0019] In the figures, the same designations are used to denote
identical elements.
DETAILED DESCRIPTION OF INVENTION
[0020] The inventive pulverized coal combination burner has a
centrally disposed pilot burner section 1 with fuel gas and oxidant
supply, a flame monitoring device and an electrical high-voltage
ignition system. Disposed around this module is an annulus 2 for
supplying the oxidant for the pulverized coal combination burner.
Swirl blades 3 for swirling the oxygen stream are disposed at the
outlet port.
[0021] The pulverized fuel is supplied outside and inside the
burner through one or more tubes (three in the example). In the
burner, the individual tubes are designed such that the
cross-section makes a systematic (continuous in the direction of
flow) transition to a curved, equiareal rectangular duct matched to
the annulus, while retaining the essentially circular entry
cross-sectional area of the tube. At the burner mouth the
rectangular duct is therefore constituted by two spatially
separated e.g. 25 mm arcuate sections with the same angle .alpha.
(alpha), e.g. 80 degrees about the central axis.
[0022] It is advantageous here if the ratio of rectangular width to
rectangular or arcuate section length is approximately 1:5.3. To
avoid pulverized fuel flow blockages, the rectangular width should
be no less than 25 mm. Inside the annular duct (inside the burner
in the direction of the burner mouth), the transition from the
tubular cross-sectional area to the final rectangular area must be
designed such that the final rectangular area is attained at the
burner outlet.
[0023] In another embodiment of the invention, the extension rays
of the walls of the annulus (4) intersect the central axis in the
direction of the burner mouth, thereby achieving an advantageous
flame geometry.
[0024] The unnecessary spaces remaining between the rectangular
outlets depending on the number of feeding elements provided can be
sealed off directly at the outlet and incorporated in the cooling
circuit.
[0025] By implementing the oxidant supply using swirl blades 3,
strong rotation is imparted to the discharging oxygen stream into
which the pulverized fuel jets discharging via the specially
designed feeding elements are sucked.
[0026] Due to the shaping of the pulverized fuel feeding elements
up to the burner mouth and immediate entry into the rotating oxygen
stream, there is no longer any areal discontinuity with different
dust velocities at the pulverized fuel outlet, thereby achieving an
even flame spread and stabilization. At the same time, the width
and length of the flame spread can be influenced using different
settings of the swirl blades 3.
[0027] The invention relates to a pulverized coal combination
burner for the gasification of pulverized fuels under high
pressures of e.g. 80 bar (8 MPa) and temperatures of e.g. 1200 to
1900.degree. C. in reactors with liquid slag removal for oxygen
gasification, comprising a cooled housing (7) for accommodating a
centrally disposed pilot burner (1) with a gas and oxidant supply
as well as an integrated flame monitoring device and a high-voltage
ignition device, said pilot burner being used for starting up the
pulverized coal combination burner unit, an annular duct (2)
disposed around said pilot burner (1) for supplying the oxidant and
another annular duct disposed around the annular oxidant duct and
having integrated feeding elements (4) for supplying pulverized
fuels, characterized in that a plurality of feeding elements (4)
are present and, inside the burner, said feeding elements (4) make
a systematic transition, up to the burner outlet, from a circular
cross-section (5) to a curved rectangular cross-section (6) matched
to the annular duct radius in a width/length ratio of approximately
1:5.3 while retaining the same area, the width of the rectangular
cross section being necessarily no less than 25 mm, and end at the
outlet immediately adjacent to the annular oxidant supply duct at
the outlet of which swirl blades (3) are provided which impart
strong rotation to the oxygen stream and therefore, by suitable
design, allow the flame geometry to be influenced.
* * * * *