WO2008084909A1

WO2008084909A1 - Variable flame oxyfuel burner with low nitrogen oxide emission

Info

Publication number: WO2008084909A1
Application number: PCT/KR2007/005512
Authority: WO
Inventors: Dong-Soon Noh; Eun-Kyung Lee
Original assignee: Korea Institute Of Energy Research
Priority date: 2007-01-09
Filing date: 2007-11-02
Publication date: 2008-07-17
Also published as: KR100820227B1

Abstract

Disclosed is a variable flame oxyfuel burner with low nitrogen oxide emission, which improves limitation in operation of conventional oxyfuel burners, freely controls the shape of a flame, and a combustion characteristic, such as a discharge, a brightness of flame, etc., while minimizing generation of a nitrogen oxide respective to an atmosphere of a low temperature or a high temperature, particularly a total operation range.

Description

VARIABLE FLAME OXYFUEL BURNER WITH LOW NITROGEN OXIDE EMISSION

Technical Field

[1] The present invention relates to a variable flame oxyfuel burner with low nitrogen oxide emission, and more particularly to an oxyfuel burner which can minimize generation of a nitrogen oxide in developing a burner which is effective, and which is considered in view of environmental preservation. Background Art

[2] An oxyfuel burner is used as thermal equipment which has been widely used for industrial and commercial purposes. The oxyfuel burner requires a performance which secures high fuel efficiency, minimizes generation of pollution-material, and achieves variable and stable flame characteristics, as well as structural simplicity and endurance.

[3] A conventional oxyfuel burner with low nitrogen oxide emission performs a method for dividing and injecting oxygen or fuel in a multistage way and forms a mixed area where fuel is thin and oxygen excesses, or a mixed area where oxygen is thin and fuel excesses, which has spatially various mixture rates according to each division rate, so as to partially decrease the highest temperature of the flame.

[4] In the above described conventional combustion method, generation of a nitrogen oxide and stability of flame are influenced by the configuration of the inlet of a nozzle, a division rate, an atmosphere around a burner, and the temperature of oxygen. Therefore, operation of maintaining optimum performance is required.

[5] Meanwhile, in an oxyfuel burner with low nitrogen oxide emission performing combustion by directly injecting fuel at high speed, the temperature of an atmosphere around a burner is low at an early stage of operation so that flame stability and combustion efficiency are low due to the structure of a nozzle. Therefore, it is impossible to perform an operation of directly injecting fuel at a high speed.

[6] Because of this, so as to maintain high combustibility and stable flame until the temperature of the atmosphere around the burner reaches a predetermined temperature, it is required that a nozzle can raise a mixture rate between fuel and oxygen. As described above, in a case where the mixture rate with fuel and oxygen increases, a high temperature flame area inevitably expands so that a nitrogen oxide can is excessively generated. Therefore, so as to lower the mixture rate between fuel and oxygen, the configuration of a nozzle of a burner can be complicated and it can be difficult to manufacture and assemble the nozzle. Disclosure of Invention Technical Problem

[7] The present invention provides a variable flame oxyfuel burner with low nitrogen oxide emission, which improves the limitation of operation in a conventional oxyfuel burner with low nitrogen oxide emission and freely controls a shape of flame, a combustion characteristic such as a discharge, a brightness of flame, etc. in a simple manner while minimizing generation of a nitrogen oxide respective to an atmosphere of a low temperature and a high temperature, particularly to an entire operating range. Technical Solution

[8] In accordance with an aspect of the present invention, there is provided a variable flame oxyfuel burner with low nitrogen oxide emission, which includes: a combustion pipe installed at a burner tile; a discharge gas fuzzy pipe integrally formed with the combustion pipe, a recirculation discharge gas feeding inlet being installed at a side of the discharge gas fuzzy pipe; an oxygen pipe installed at an interior of the discharge gas fuzzy pipe and the combustion pipe, an oxygen nozzle for injecting oxygen fed from an oxygen feeding inlet included at one end of the oxygen pipe being installed at the oxygen pipe; a fuel feeding pipe installed at an interior of the discharge gas fuzzy pipe and the combustion pipe, a fuel nozzle for injecting fuel fed from a fuel feeding inlet included at one end of the fuel feeding pipe being installed at the fuel feeding pipe; and a burner for ignition installed at an interior of the discharge gas fuzzy pipe and the combustion pipe, the burner for ignition generating a combustion reaction at one end of the combustion pipe, wherein the fuel nozzle has a slot-shaped section and can rotate. Advantageous Effects

[9] According to the present invention, a limitation in operation of a conventional oxyfuel burner with low nitrogen oxide emission, is improved, and a shape of the flame, a combustion characteristic such as a discharge, a brightness of flame, etc. can be freely controlled in a simple manner while generation of a nitrogen oxide respective to an atmosphere of a low temperature and a high temperature, particularly to an entire operating range is minimized. Brief Description of the Drawings

[10] The foregoing and other objects, features and advantages of the present invention will become more apparent from the following detailed description when taken in conjunction with the accompanying drawings in which:

[11] FIG. 1 is a sectional view illustrating an oxyfuel burner according to an embodiment of the present invention;

[12] FIG. 2 is a left side view illustrating an oxyfuel burner according to an embodiment of the present invention; and [13] FIG. 3 is a right side view illustrating an oxyfuel burner according to an embodiment of the present invention. Mode for the Invention

[14] In a variable flame oxyfuel burner with low nitrogen oxide emission according to the present invention, a slot-shaped nozzle rotates so as to adjust a mixture rate between oxygen and fuel fed from the nozzle, thereby controlling a temperature of the flame and minimizing generation of a nitrogen oxide.

[15] A variable flame oxyfuel burner with low nitrogen oxide emission according to the present invention includes: a combustion pipe installed at a burner tile; a discharge gas fuzzy pipe which is integrally formed with the combustion pipe, a recirculation discharge gas feeding inlet being installed at a side of the discharge gas fuzzy pipe; an oxygen pipe which is installed at the interior of the discharge gas fuzzy pipe and the combustion pipe and has an oxygen nozzle for injecting oxygen fed from an oxygen feeding inlet; a fuel feeding pipe which is installed at the interior of the discharge gas fuzzy pipe and the combustion pipe and has a fuel nozzle for injecting fuel fed from the fuel feeding inlet; and a burner for ignition generating a combustion reaction at one end of the combustion pipe, wherein the fuel nozzle or the oxygen nozzle has a slot- shaped section and can rotate.

[16] At this time, the diameter of the fuzzy pipe is bigger than the diameter of the combustion pipe, and a flame sensor is included at one end of the combustion pipe.

[17] Also, a view window, which allows the user to observe a combustion state of one end of the combustion pipe, is included at the interior of the discharge gas fuzzy pipe and the combustion pipe, and the view window is integrally formed while extending along a longitudinal direction of the oxygen or fuel feeding pipe.

[18] The fuel nozzle or the oxygen nozzle can be rotated by a rotating means included at the fuel feeding pipe or the oxygen feeding pipe, and the rotating means includes a worm wheel formed at the fuel feeding pipe and a worm gear assembled with the worm wheel so as to rotate.

[19] A fuel nozzle, an oxygen nozzle, a recirculation discharge gas nozzle, a burner for ignition, and a flame sensor are included at one end of the combustion pipe of the oxyfuel burner according to the present invention. The fuel nozzle or the oxygen nozzle has a slot-shaped section and can separately rotate, and the oxygen nozzle or the fuel nozzle, which has a circular sectional shape, is installed in such a manner that it is deviated about a central axis of the recirculation discharge gas nozzle.

[20] Particularly, when the fuel nozzle has a slot-shaped section, the oxygen nozzle has a circular sectional shape, and when the oxygen nozzle has a slot-shaped section, the fuel nozzle has a circular sectional shape. Only a nozzle having a slot-shaped section separately rotates.

[21] At this time, the interval between the center of the oxygen nozzle and the center of the fuel nozzle is fixed so as to allow flame to be stably formed at a total temperature range from a low temperature to a high temperature, and a nozzle having a slot-shaped section can rotate at a fixed place while having a predetermined angle so that the injection- shape of fuel or oxygen can be varied according to the rotational angle of the nozzle.

[22] Also, a nozzle having a circular sectional shape can maintain a constant fuel or oxygen injection shape. Oxygen or fuel injected with such a constant injection shape is mixed in various ways with oxygen or fuel injected with an injection shape spatially varying according to the rotation of the slot-shaped nozzle, so as to form a mixture area having various mixture rates.

[23] Hereinafter, the details of a purpose, a technical construction, a function, and an effect according to the present invention will be clearly understood by a description with reference to the accompanying drawings illustrating an exemplary embodiment of the present invention.

[24] FIG. 1 is a sectional view of an oxyfuel burner according to an embodiment of the present invention, FIG. 2 is a left side view of an oxyfuel burner according to an embodiment of the present invention, and FIG.3 is a right side view of an oxyfuel burner according to an embodiment present invention.

[25] According to an embodiment of the present invention, a fuel nozzle has a slot- shape.

[26] The oxyfuel burner according to the present invention is installed at a burner tile

200.

[27] A combustion pipe 104 is installed at the burner tile 200, and the combustion pipe

104 is inserted into a hole formed at the burner tile 200 and is fixed in the burner tile 200 by an installing flange 102 integrated with the combustion pipe 104.

[28] A discharge gas fuzzy pipe 100 is integrally formed with the combustion pipe 104 so as to be communicated with the combustion pipe 104.

[29] A discharge gas feeding inlet 101 is formed at one side of the discharge gas fuzzy pipe 100.

[30] Also, the diameter of the discharge gas fuzzy pipe 100 is bigger than the diameter of the combustion pipe 104. Because of this, when discharge gas is fed to the discharge gas fuzzy pipe 100, discharge gas is easily injected toward the combustion pipe 104 due to a difference between diameters of the discharge gas fuzzy pipe 100 and the combustion pipe 104.

[31] A fixing member 150 is installed at one side of the discharge gas fuzzy pipe 100, and the fixing member 150 is coupled with connecting flanges 103 and 153 formed at the discharge gas fuzzy pipe 100, respectively.

[32] An oxygen pipe 101 and a fuel feeding pipe 120 are inserted in the fixing member

150, the oxygen pipe 101, and the fuel feeding pipe 120 pass the interior of the discharge gas fuzzy pipe 100 and the combustion pipe 104 so as to extend to one end of the combustion pipe 104.

[33] At this time, the oxygen pipe 110 and the fuel feeding pipe 120 are deviated about a central axis of the combustion pipe 104. The feeding inlet 111 is integrally formed at the oxygen pipe 110. As shown in FIG. 2, a view window 140 is installed in an extension direction of the oxygen pipe 110 so as to allow a user to observe a combustion state, and the oxygen feeding inlet 111 is connected with the oxygen pipe 110 in a perpendicular direction.

[34] Also, a fuel feeding inlet 124 for feeding fuel is formed at the fuel feeding pipe 120, and fuel is fed from the fuel feeding source. The oxygen nozzle 112 and the fuel nozzle 123 are installed at the ends of the oxygen pipe 110 and the fuel feeding pipe 120, respectively.

[35] The fuel nozzle 123 has a slot-shape and can rotate. The fuel nozzle 123 is rotated by the rotation of the fuel feeding pipe 120. The rotation means for rotating the fuel feeding pipe 120 includes a worm wheel 121 formed at a circumference of the fuel feeding pipe 120 and a worm gear 122 assembled with the worm wheel 121 so as to be rotated by a driving means which is not shown.

[36] At this time, a sealing member 151 is installed between the fuel feeding pipe 120 and the fixing member 150 so as to prevent gas from leaking and to allow the fuel feeding pipe 120 to rotate.

[37] A flame monitor 140 for sensing a combustion state of one end of the combustion pipe 104 is installed at the fixing member 150, and the flame monitor 140 is electrically connected with the flame sensor 141 of one end of the combustion pipe 104.

[38] The operating method according to an embodiment of the present invention will be described below.

[39] Firstly, at an initial stage of operation under the low atmospheric temperature, the fuel nozzle 123 having a slot- shaped section is controlled in such a manner that a longitudinal direction of the slot thereof parallels a connecting line connecting between central axes of the fuel nozzle 123 and the oxygen nozzle 112, thereby shortening a distance between one end of the slot in the longitudinal direction and a front end of the oxygen nozzle 112. Therefore, a mixture rate between fuel and oxygen increases so that the flame is stably ignited and maintained at a position near the front end of the fuel nozzle 105.

[40] Also, when combustion is maintained so that an atmospheric temperature suf- ficiently increases, the fuel nozzle 123 having a slot-shaped section is rotated at 90 degrees by controlling a rotational angle thereof in such a manner that the longitudinal direction of the slot of the fuel nozzle 123 is positioned perpendicularly to the connecting line connecting between central axes of the fuel nozzle 123 and the oxygen nozzle 112.

[41] Therefore, the end of the slot of the fuel nozzle in a longitudinal direction is positioned sufficiently far from the front end of the oxygen nozzle 112, so as to wholly reduce a mixture rate between fuel and oxygen. As a result, it is possible to obtain a partially optimum mixture rate. Also, the other area, which is relatively large, includes widely distributed inflammation limit areas, such as excessive fuel (thin oxygen) areas and excessive oxygen (thin fuel) areas.

[42] Therefore, an optimum mixture rate area where the temperature of a flame can be highest is reduced so that a combustion flame having a relatively low temperature is formed, thereby restraining generation of a nitrogenous compounds.

[43] Particularly, if an injecting speed of each nozzle increases, injected fuel and oxygen are stimulated to be mixed with combustion gas before joining a combustion reaction. Therefore, each density of fuel and oxygen further decreases in a final combustion stage so that the temperature of flame is lowered. As a result, generation of nitrogen oxide can be minimized.

[44] Accordingly, when the atmospheric temperature is sufficiently high, the rotating angle of the fuel nozzle 123 including an inlet having a slot-shaped section is controlled so as to form combustion flame with various shapes.

[45] Additionally, when discharge gas having a high temperature is fed to the discharge gas fuzzy pipe 100, discharge gas halts within the combustion pipe 104, which has a relatively small sectional area, so as to be mixed with oxygen and fuel, thereby reducing density of oxygen in an inflammation mixture rate. Therefore, the temperature of a flame decreases so that generation of a nitrogen oxide can be effectively restrained.

[46] Also, so as to operate a typical oxyfuel burner, normal air is fed instead of recirculation discharge gas, and a very small amount of oxygen is fed through the oxygen nozzle (oxygen load effect), thereby maintaining stability of flame. Therefore, one oxyfuel burner can be used for an air burner and an oxygen burner.

[47] Also, it is possible to perform such combustion in a state where the oxygen nozzle

122 instead of the combustion nozzle 123 has a slot-shape.

Claims

[1] A variable flame oxyfuel burner with low nitrogen oxide emission, comprising: a combustion pipe installed at a burner tile; a discharge gas fuzzy pipe integrally formed with the combustion pipe, a recirculation discharge gas feeding inlet being installed at a side of the discharge gas fuzzy pipe; an oxygen pipe installed at an interior of the discharge gas fuzzy pipe and the combustion pipe, an oxygen nozzle for injecting oxygen fed from an oxygen feeding inlet included at one end of the oxygen pipe being installed at the oxygen pipe; a fuel feeding pipe installed at an interior of the discharge gas fuzzy pipe and the combustion pipe, a fuel nozzle for injecting fuel fed from a fuel feeding inlet included at one end of the fuel feeding pipe being installed at the fuel feeding pipe; and a burner for ignition installed at an interior of the discharge gas fuzzy pipe and the combustion pipe, the burner for ignition generating a combustion reaction at one end of the combustion pipe, wherein the fuel nozzle has a slot- shaped section and can rotate.

[2] A variable flame oxyfuel burner with low nitrogen oxide emission, comprising: a combustion pipe installed at a burner tile; a recirculation discharge gas fuzzy pipe integrally formed with the combustion pipe, a recirculation discharge gas feeding inlet being installed at a side of the recirculation discharge gas fuzzy pipe; an oxygen pipe installed at an interior of the discharge gas fuzzy pipe and the combustion pipe, an oxygen nozzle for injecting oxygen fed from an oxygen feeding inlet included at one end of the oxygen pipe being installed at the oxygen pipe; a fuel feeding pipe installed at an interior of the discharge gas fuzzy pipe and the combustion pipe, a fuel nozzle for injecting fuel fed from a fuel feeding inlet included at one end of the fuel feeding pipe being installed at the fuel feeding pipe; and a burner for ignition installed at an interior of the discharge gas fuzzy pipe and the combustion pipe, the burner for ignition generating a combustion reaction at one end of the combustion pipe, wherein the oxygen nozzle has a slot-shaped section and can rotate.

[3] The variable flame oxyfuel burner with low nitrogen oxide emission as claimed in claim 1 or 2, wherein the oxygen pipe and the combustion pipe are deviated about a central axis of the combustion pipe. [4] The variable flame oxyfuel burner with low nitrogen oxide emission as claimed in claim 1 or 2, wherein a diameter of the fuzzy pipe is bigger than a diameter of the combustion pipe. [5] The variable flame oxyfuel burner with low nitrogen oxide emission as claimed in claim 1 or 2, wherein a flame sensor is included at one end of the combustion pipe. [6] The variable flame oxyfuel burner with low nitrogen oxide emission as claimed in claim 1 or 2, wherein a view window is included in an interior of the discharge gas pipe and the combustion pipe so as to allow a user to observe a combustion state of one end of the combustion pipe. [7] The variable flame oxyfuel burner with low nitrogen oxide emission as claimed in claim 6, wherein the view window is integrally formed with the oxygen pipe while extending in a longitudinal direction of the oxygen pipe. [8] The variable flame oxyfuel burner with low nitrogen oxide emission as claimed in claim 1 or 2, wherein the fuel nozzle and the oxygen nozzle can be rotated by a rotating means included in the fuel feeding pipe or the oxygen feeding pipe. [9] The variable flame oxyfuel burner with low nitrogen oxide emission as claimed in claim 8, wherein the rotating means includes a worm wheel formed at the fuel feeding pipe and a worm gear assembled with the worm wheel so as to be rotated.