KR101512352B1 - Low NOx Burner using forced internal recirculation of flue gas and method thereof - Google Patents

Abstract

According to the present invention, a low NOx combustion device includes: a first fuel injection body supplying a main fuel into a combustion furnace; at least one or more second injection bodies arranged around the first fuel injection body, and arranged to enable a front end thereof to be inserted into the combustion furnace; a recirculation guidance unit enabling a combustion gas generated in the combustion furnace to be recirculated by a hydrodynamic force; a fuel supply unit supplying fuel to the first fuel injection body and the second fuel injection body; an oxidizing agent supply unit supplying an oxidizing agent to a space between the first fuel injection body and the second fuel injection body; and an air multi-stage sleeve arranged to surround the first fuel injection body for an air multi-stage. The oxidizing agent supplied from the oxidizing agent supply unit is supplied to the multi stages through an internal and an external air multi-stage sleeve. The present invention applies an inner recirculation technique to the combustion gas generated inside a combustion chamber, where a plurality of flames are formed, to enable the combustion gas to not to be transferred to an external connection passage of the combustion chamber, but to the inside of the combustion chamber without additional devices.

Description

BACKGROUND OF THE INVENTION 1. Field of the Invention [0001] The present invention relates to an ultra low NOx combustion apparatus and an operation method thereof,

The present invention relates to an ultra low NO x combustion apparatus through internal recirculation of combustion gas, and more particularly, to an ultra-low NO x combustion apparatus that internally recirculates combustion gas to the inside of a combustion chamber, And an ultra low NOx combustion apparatus using recirculation technology.

At present, the main energy source of mankind is hydrocarbon fossil fuel. However, environmental pollution caused by combustion products of fossil fuels is seriously raised. In addition to nitrogen oxides (NOx) and carbon dioxide (CO ₂ ), the main sources of environmental pollution include carbon monoxide (CO) and soot generated by incomplete combustion of fuel.

In conventional combustors using fossil fuels, it is inevitable to produce nitrogen oxides (NOx) having chemical formulas of NO and NO2 by chemical reaction at the time of combustion. The low NOx combustion technology for suppressing the generation of NOx has been developed to improve the structure of the combustor such as the mixture form of the fuel and the air and the air-fuel ratio. Nitrogen oxides generated in the combustion process react with other oxygen in the atmosphere and cause environmental problems such as smog and atmospheric ozone increase. In particular, emissions from these combustion processes are harming the environment and human health, and countries are tightening regulations on an increasingly stringent level.

The types of nitrogen oxides can be classified into thermal NOx, rapid NOx, and fuel NOx depending on the cause. The thermal nitrogen oxides are produced by the reaction of nitrogen in the air with oxygen at a high temperature of 1600 ° C or higher. Rapid nitrogen oxides are generated at the initial stage of combustion in the combustion of hydrocarbon-based fuels. The fuel nitrogen oxides react with the nitrogen components contained in the fuel Lt; / RTI > Even in the countermeasures against such nitrogen oxides, it is effective to control matters related to thermal NOx and Prompt NOx because gaseous fuels such as natural gas do not contain nitrogen components in the fuel.

Nitrogen oxides cause photochemical smog and acid rain and are known to have serious effects on flora and fauna. For a long time many researchers have studied various ways to reduce NOx.

As a result of this, low NOx methods currently being tried include exhaust gas recirculation, water or steam injection, multi-stage combustion of air and fuel, selective non-catalytic reduction (SNCR), selective catalytic reduction (SCR) catalytic reduction). Recently, advanced countries are attempting to recycle NOx in the afterburning region, and it is known that NOx reduction efficiency and economic efficiency are high.

As a conventional method for reducing NOx as described above, Korean Patent Laid-Open No. 10-2005-0117417 is exemplified. In order to reduce the amount of nitrogen oxides (NOx) generated on the above-mentioned No. 10-2005-0117417, combustion air is supplied in three stages by mixing general air and flue gas, A three-stage burner recirculation flue gas for liquid and gas is provided for minimizing the generation of localized high temperature by burning and extending the combustion region to achieve uniform heat inside the boiler.

On the other hand, in the cited document, separate devices such as a plurality of exhaust gas supply pipes, recirculation ducts, and dampers are provided as elements for recirculating the exhaust gas so that the exhaust gas is re-introduced into the combustion furnace, There is a disadvantage in that a required space is increased.

Meanwhile, referring to the registered patent No. 1203189 filed by the present inventor, there is provided an internal recirculation technique in which combustion gas generated in a combustion chamber is transferred not in an external connection passage of a combustion chamber but in a combustion chamber without a separate device, There is a limit to the specific structure for forming a lean flame at the center of the furnace or the description of specific factors that can reduce the formation of nitrogen oxides.

Korean Patent Publication No. 10-2005-0117417 Korean Patent No. 10-1203189

SUMMARY OF THE INVENTION Accordingly, the present invention has been made keeping in mind the above problems occurring in the prior art, and an object of the present invention is to provide an apparatus and a method for supplying an oxidizing agent to a central region of a combustion furnace, And an object of the present invention is to provide an ultra-low nitrogen oxide combustion apparatus employing an internal recirculation technique that allows the combustion to be carried out without any problems.

Another object of the present invention is to provide a high-efficiency and low-pollution firing field through a multi-stage fuel supply nozzle structure composed of a primary fuel injection body for supplying a main fuel and a secondary fuel injection for supplying an auxiliary fuel.

According to an aspect of the present invention, there is provided an ultra low NO x combustion apparatus comprising: a primary fuel injector for injecting a main fuel into a combustion furnace; A secondary fuel injector disposed at least in the periphery of the primary fuel injector and disposed so that its tip enters the combustion furnace; A recirculation inducing unit for recirculating the combustion gas generated in the combustion furnace to the combustion furnace by a hydrodynamic force; A fuel supply unit for supplying fuel to the primary fuel injection body and the secondary fuel injection body; An oxidant supplier for supplying an oxidant to a space between the primary fuel injector and the secondary fuel injector; And an air multistage sleeve arranged to surround the primary fuel injection body for air multistage, wherein the oxidant supplied from the oxidant supply part is supplied in multiple stages through the inner and outer portions of the air multistage sleeve.

A first performance index η ₁ indicating premixed strength when defining a discharge hole diameter of the primary fuel injection body as B, a diameter of the air multistage sleeve as D, and an inner diameter of the recirculation induction portion as C, . ≪ / RTI >

The value of the first figure of merit may preferably be in the range of 0.3 to 0.5.

The ultra low nitrogen oxide combustion apparatus may further include: a swirl chamber disposed at a front end of the primary fuel injection body; And a central oxidant injecting part for injecting the oxidant supplied from the oxidant supplying part into the combustion furnace along the inside of the primary fuel injecting body.

A second performance index, η ₂ , which represents a nozzle shape coefficient, when the discharge port diameter of the primary fuel injection device is defined as B and the diameter of the swirler is defined as A, The value may preferably be in the range of 1.5 to 2.0.

A third performance index η ₃ indicating the swirl index when the diameter of the discharge port of the primary fuel injection body is B, the diameter of the swirler is A, and the inner diameter of the recirculation induction portion is C, And the value of the third figure of merit is preferably in the range of 0.55 to 0.75.

When the distance between the FIR ports is defined as E, and the diameter of the fuel pipe is defined as E, a fourth performance index representing the recirculation flow rate,? ₄ , may be preferably set as follows.

When a discharge port diameter of the primary fuel injection body is defined as B and an inner diameter of the recirculation induction portion is defined as C, a fifth performance index representing the combustor outlet flow rate,? ₅ , may be preferably set as follows.

The ultra low nitrogen oxide combustion apparatus may further include a recirculation promoting protrusion laid on the outer surface of the air multi-stage sleeve, wherein the recirculation promoting protrusion increases the flow rate of the combustion gas flowing between the recirculating induction portion and the air multi- May be preferred.

It is preferable that a plurality of the secondary fuel injection bodies are disposed so as to be spaced apart from each other on the same circumference around the primary fuel injection body and that the secondary fuel injection body injects fuel in the radial direction thereof have.

It may be preferable that the radial injection angle of the secondary fuel injection body injects fuel between an angle toward the adjacent secondary fuel injection body and an angle toward the alternately adjacent secondary fuel injection body.

It is preferable that the axial fuel injection angle of the secondary fuel injection body is in the range of 10 ° to 80 °.

는 바람직하게 20에서 50의 범위로 설정되는 것이 바람직하다.The fuel injection speed of the primary fuel injector

Is preferably set in the range of 20 to 50. [

은 바람직하게 하기 식의 범위로 설정되는 것이 바람직하다.The fuel injection speed of the secondary fuel injection body,

Is preferably set in the range of the following formula.

The recirculating induction unit may include an internal recirculating sleeve disposed to be inclined with respect to the secondary fuel injector, a connecting guide extending from a rear end of the internal recirculating sleeve, and a moving member connected to a rear end of the connecting guide to change a moving direction of the combustion gas Spray nozzles < / RTI >

The injection nozzle may be arranged to be inclined between the primary fuel injection body and the recirculation induction portion so as to reduce the width between the primary fuel injection body and the recirculation induction portion, which is the space of the oxidant.

It is preferable that the primary fuel injector injects the supplied main fuel in its radial direction and tangential direction.

It is preferable that the tip of the secondary fuel injector is disposed further into the combustion furnace than the tip of the primary fuel injector.

Wherein the primary fuel injection body forms a primary space which is a fuel rich region inside the combustion furnace and the secondary fuel injection body forms a secondary space which is a fuel lean region at the rear end of the primary space, May be desirable.

The ultra low nitrogen oxide combustion apparatus according to the present invention allows the combustion gas generated in the combustion chamber in which the multi-flame field is formed to be transferred through the internal recirculation technique without any additional device in the combustion chamber, not in the external connection passage of the combustion chamber.

By optimizing the shape of the internal recycle derivative, the combustion gas in the combustion furnace is mixed with the oxidizing agent sucked in by the heat and hydrodynamic induction technique without external power, and burned, thereby enabling the ultra low nitrogen oxide operation.

The present invention provides an air supply process for forming a lean flame by supplying an oxidant to the center of the flame, or prevents an increase in nitrogen oxide production due to local hot spots at the center of the flame. This prevents the overheating of the swirler and the fuel spray tip.

Further, the present invention enables a smooth recirculating flow of the combustion gas generated in the combustion furnace through the structure of the recirculating induction portion and the air multistage sleeve, and thereby enables the combustion of the flame due to the flow contrary to the recirculating flow of the central portion, Thereby preventing occurrence of instability phenomenon.

Further, since no separate power supply device is required, it is possible to simplify the installation and increase the circulation efficiency of the combustion gas.

In addition, according to the present invention, the combustion gas passing through the recirculation inducing unit is supplied again to the combustion furnace along with the oxidizing agent and is burnt, thereby forming a stable flame.

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is an overall configuration diagram of an ultra low nitrogen oxide combustion apparatus according to a first embodiment of the present invention;
FIG. 2 is a view of the combustion apparatus of FIG. 1 viewed from the inside of the combustion furnace, showing an embodiment in which an auxiliary fuel is injected from a secondary fuel injector,
FIG. 3 is a view showing another embodiment in which auxiliary fuel is injected from a secondary fuel injector as seen from the inside of a combustion furnace of FIG. 1,
FIG. 4 is a drawing showing the symbols constituting the important figure of merit,
5A to 5F are graphs showing important performance indices of the ultra low NOx combustion apparatus of the present invention,
FIG. 6 is an overall configuration diagram of an ultra low nitrogen oxide combustion apparatus according to a second embodiment of the present invention, and FIG.
7 is a view for explaining the axial fuel injection angle of the secondary fuel injection body.

These and other objects, features and other advantages of the present invention will become more apparent by describing in detail preferred embodiments of the present invention with reference to the accompanying drawings. The embodiments described are provided by way of illustration for the purposes of illustration and are not intended to limit the scope of the invention.

Each component constituting the ultra low nitrogen oxide combustion apparatus of the present invention may be used integrally or individually as needed. In addition, some components may be omitted depending on the usage pattern.

BEST MODE FOR CARRYING OUT THE INVENTION Hereinafter, an ultra low nitrogen oxide combustion apparatus according to an embodiment of the present invention will be described in detail with reference to the accompanying drawings.

Ultra low nitrogen oxide  Overall configuration of the combustion device

First, referring to FIG. 1, the overall configuration of the ultra low nitrogen oxide combustion apparatus 100 according to the first embodiment of the present invention will be described.

The ultra-low nitrogen oxide combustion apparatus 100 surrounds the primary fuel injector 10 disposed at the center of the opening formed in the front of the combustion furnace 1 and the primary fuel injector 10, A swirler 30 disposed at the front end of the primary fuel injector 10, a secondary fuel injector 20 disposed between the primary fuel injector 10 and the secondary fuel injector 20, An air multistage sleeve 60 disposed to surround the primary fuel injection body 10 and the swasher 30 and a recirculation promoting protrusion 90 attached to the outer surface of the air multistage sleeve 60 ). The recirculation inducing portion 40 is disposed adjacent to the secondary fuel injector 20.

The primary fuel injection body 10 includes a transfer part 13 connected to the first fuel line 51 and an enlargement part 11 connected directly to the transfer part 13. The transfer part 13 is for transferring the main fuel to the enlargement part 11 safely and is preferably made of a material having high durability and can be formed uniformly in diameter.

The enlarged portion 11 may have a shape gradually increasing in diameter as an embodiment, and injects the supplied main fuel through the outer peripheral surface thereof. That is, the fuel that has entered the enlarged portion 11 through the injection hole (not shown) formed on the outer peripheral surface of the enlarged portion 11 is radially injected into the internal space between the fuel injection bodies 10 and 20 15). That is, the fuel in the enlarged portion 11 is injected onto the incoming oxidant along the radial direction of the enlarged portion 11.

On the other hand, a central oxidant spraying part 85 may be disposed along the inside of the primary fuel injector 10. Here, it is possible to insert the nozzle at the end of the central oxidant spraying section 85, thereby making it possible to adjust the air supply amount. The central oxidant spraying unit 85 causes the oxidant supplied from the oxidant supply unit 80 to flow along the central axis of the primary fuel injector 10 and then flows into the primary space 72 as the flame center of the combustion furnace 1, .

Thereby promoting the mixing effect of the flame and the oxidizing agent in the primary space 72, which is the center of the flame, and thereby suppressing the formation of redness, thereby inducing the formation of blue salt. In addition, it reduces the local high temperature region around the flame center, thereby reducing the generation of nitrogen oxides.

The secondary fuel injection bodies 20 are arranged at equal intervals on the same circumference with the primary fuel injection body 10 as a center. Specifically, six to twelve secondary fuel injection bodies 20 are disposed, and preferably eight secondary fuel injection bodies 20 are arranged with an equal interval maintained. The tip end of the secondary fuel injector 20 is further inserted into the combustion furnace 1 as compared with the tip end of the primary fuel injector 10. The tip structure of the secondary fuel injection body 20 can be inclined at an inclination in one direction. Specifically, it can be inclined in such a manner as to be gradually away from the opening portion 3 in the direction toward the center of the furnace 1.

The fuel injected from the secondary fuel injection body 20 can be injected in the radial direction of the secondary fuel injection body 20. [ The secondary fuel injection body 20 causes the auxiliary fuel to be injected in the radial direction, not in the axial direction thereof, thereby generating the rotational flow in the combustion furnace 1. In the present invention, the auxiliary fuel may be discharged clockwise or counterclockwise on the circumference where a plurality of secondary fuel injection bodies 20 are disposed (see 25 in FIG. 2 or 25 'in FIG. 3). And is shown as being sprayed clockwise as an example in the drawing.

In the present invention, the fuel injection direction from any one of the plurality of secondary fuel injection bodies 20 is set so as to face the adjacent secondary fuel injection bodies 20 (see Fig. 2). On the other hand, as another embodiment, the fuel injection direction from any one of the plurality of secondary fuel injection bodies 20 is set so as to face the other secondary fuel injection bodies 20 alternately (see FIG. 3). On the other hand, the radial injection angle from any one of the plurality of secondary fuel injection bodies 20 is set such that the angle between the angle toward the adjacent secondary fuel injection body and the angle toward the alternate secondary fuel injection body, As shown in FIG.

3 shows that only four secondary fuel injection bodies 20 out of the eight arranged secondary fuel injection bodies 20 inject fuel, but this is for clearly indicating the injection direction, It is assumed that fuel is injected from the carcass 20.

The primary fuel injection body 10 and the secondary fuel injection body 20 are both formed as a hollow cylindrical tube. An oxidant is supplied to the space between the primary fuel injection body 10 and the secondary fuel injection body 20 from the oxidant supply part 80. The oxidant is supplied into the furnace 1 directly or indirectly through the swirler 30 without being supplied into the furnace 1 or through the swirler 30 with axial or tangential momentum being formed.

Liquid fuel is supplied to the primary fuel injection body 10 and the secondary fuel injection body 20 from the fuel supply part 50 while being divided into a main fuel and a secondary fuel. The impurities are removed from the fuel supply unit 50 through a filter (not shown) and branched into the first line 51 and the second line 52 after being pumped by a pump (not shown) . Solenoid valves 55 and 56 are provided in the lines 51 and 52 so as to appropriately supply and shut off the liquid fuel supplied as the main fuel and the secondary fuel.

The swirler 30 is arranged at the tip of the primary fuel injector 10 so that the premixer can be supplied diagonally to the axial direction of the primary fuel injector 10. In addition, the diagonal fed premixer is in swirling flow and allows the generation of vortices (see reference numeral 32 in FIG. 2). In order to realize the above function, the swirler 30 may include a hollow cylindrical body as an example and a wing-shaped guide plate disposed diagonally to the axial direction inside the body. A hollow cylindrical insertion hole (not shown) is formed in the body so as to be connected to one end of the guide plate. The primary fuel injection body 10 is fixedly inserted through the insertion hole so that the swirler 30 is disposed so as to surround the front end portion of the primary fuel injection body 10. [

The recirculation induction unit 40 includes an internal recirculation sleeve 41, an internal recirculation sleeve 41, and an internal recirculation sleeve 41. The internal recirculation sleeve 41 is disposed obliquely with respect to the secondary fuel injection body 20 on an opening (not shown) An injection nozzle 45 connected to the rear end of the connection guide 43 for changing the direction of the flow of the combustion gas flowing therethrough and an inclined member 45 inclined to the inner lower end of the recirculation induction unit 40, (47).

The inner recirculating sleeve 41 is disposed so as to be inclined toward the center of the opening 3 from the front end to the rear end, which is the first inflow portion of the combustion gas. That is, the inner width gradually gets wider toward the rear end of the inner recirculation sleeve 41. The connecting guide 43 maintains a constant width as it allows a gentle flow of the flue gas introduced through the inner recirculation sleeve 41.

The injection nozzle 45 injects the combustion gas flowing in the combustion furnace 1 through the internal recirculation sleeve 41 and the connection guide 43 into the space between the primary fuel injection body 10 and the recirculation induction portion 40 . The injected combustion gas flows into the combustion furnace 1 together with the oxidizing agent. The injection nozzle 45 is disposed at an angle between the primary fuel injection body 10 and the recirculation induction portion 40. That is, the structure between the primary fuel injection body 10 and the recirculation induction portion 40 is reduced to realize an orifice type structure. The arrangement of the injection nozzles 45 as described above is such that the flow rate of the oxidant supplied to the space between the primary fuel injection body 10 and the secondary fuel injection body 20 is increased, Flow.

That is, since the space between the primary fuel injection body 10 and the injection nozzle 45 is narrowed, the flow rate of the oxidant is increased by Bernoulli's theorem. Through this structure, the flow generated in the combustion furnace 1 enables an increase in momentum.

The inclined member 47 is a structure disposed on the boundary line between the connection guide 43 and the injection nozzle 45. As a result, the width of the combustion gas can be controlled to control the flow rate.

The air multi-stage sleeve 60 is a hollow cylindrical structure, and the oxidant supplied from the oxidant supply unit 80 is separately supplied to the inside and the outside of the air multi-stage sleeve 60, thereby enabling multi-stage supply of the oxidant, As a result, the multistage flame is easily formed in the combustion furnace 1.

The recirculation promoting protrusion 90 is disposed on the outer peripheral surface of the air multi-stage sleeve 60. Specifically, the recirculation promoting protrusion 90 functions to narrow the space between the injection nozzle 45 and the air multi-stage sleeve 60 constituting the recirculation induction unit 40. Through the above-described structure, the flow rate of the combustion gas flowing from the combustion furnace 1 through the recirculation induction portion 40 is increased as it passes near the recirculation promoting projection portion 90. This prevents separation of the combustion gas re-flowing into the combustion furnace 1 through the recirculation induction unit 40, and consequently promotes recirculation of the combustion gas.

Next, with reference to Figs. 4 to 5E, a description will be given of important performance indexes capable of determining the performance of the ultra low nitrogen oxides combustion apparatus 100. Fig.

The symbol used in the equation for determining the important figure of merit is defined as follows.

A is the diameter of the swirler 30, B is the diameter of the fuel head, C is the inner diameter of the recirculation inducing portion 40, D is the diameter of the air multistage sleeve 60, E is the distance between the FIR ports, Diameter of pipe

Here, the diameter of the fuel head is the diameter of the discharge port of the primary fuel injector 10 and the diameter of the portion of the enlarged portion 11 coupled to the swirler 30, and the diameter of the fuel pipe is the diameter The diameter of the transfer portion 13 into which the fuel flows in the carcass 10 and the distance between the FIR ports means the distance between the injection nozzles 45 in the recirculation inducing portion 40. [

First, the first performance index,? ₁ , represents the pre-mix strength, and can be set by the following equation.

The first figure of merit refers to the ratio of the internal burner area to the total oxidizer feed area and represents the ratio of premixed air area to pure oxidant feed area.

Referring to FIG. 5A, in order to keep the incidence rate of nitrogen oxides below 20, the value of the first figure of merit is in the range of 0.3 to 0.5. Preferably 0.4.

Next, the second performance index, eta _2, represents the nozzle shape coefficient, which can be set by the following equation.

The second figure of merit refers to the ratio between the swirler diameter and the fuel head diameter and is used as a design index of the rapid premix burner head.

Referring to FIG. 5B, in the present invention, the value of the second figure of merit is preferably in the range of 1.5 to 2.0 in order to keep the incidence of nitrogen oxides below 20.

Next, the third performance index, eta ₃ , represents the swirl index, which can be set by the following equation.

The third figure of merit refers to the ratio of the swirl area to the total oxidant feed area, which can represent the swirl strength as a ratio of the area occupied by the swirl in the total oxidant feed area.

Referring to FIG. 5C, in order to keep the incidence of nitrogen oxides below 20, the value of the third performance index is in the range of 0.55 to 0.75. Preferably about 1.42.

Next, the fourth performance index,? _4, represents the recirculation flow rate, and can be set by the following equation.

The fourth performance index means a flow velocity through an area of the area between the end portions of the injection nozzle 45 excluding the area of the transfer part 13. [

Referring to FIG. 5D, in order to keep the incidence rate of nitrogen oxides below 20, the value of the fourth performance index is in the range of 45 to 60.

Next, the fifth performance index,? _5, represents the combustor outlet flow rate, and can be set by the following equation.

The fifth performance index means a flow velocity through an area excluding the area of the fuel head in the inner area of the connection guide 43. [

Referring to FIG. 5E, in order to keep the incidence rate of nitrogen oxides below 20, the value of the fifth performance index is in the range of 30 to 50.

는 바람직하게 20에서 50의 범위로 설정되는 것이 바람직하다.Here, the fuel injection speed of the primary fuel injector

Is preferably set in the range of 20 to 50. [

은 바람직하게 하기 식의 범위로 설정되는 것이 바람직하다.The fuel injection speed of the secondary fuel injector

Is preferably set in the range of the following formula.

1, the fuel injected from the secondary fuel injector 20 is injected into the secondary fuel injector 20 at an angle θ of 10 ° to 80 ° with respect to a plane perpendicular to the axial direction of the secondary fuel injector 20 Lt; RTI ID = 0.0 > range. ≪ / RTI >

Next, the sixth performance index,? ₆ , represents the preliminary mixing ratio, and can be set by the following equation.

The sixth performance index means the ratio of the pre-mixed fuel flow rate to the total fuel flow rate.

Referring to FIG. 5F, in order to keep the incidence of nitrogen oxides below 20, the value of the sixth performance index is in the range of 4 to 22. As can be seen from the above, the lower the premixing ratio, the better the nitrogen oxide reduction effect, but the disadvantage is that the flame instability phenomenon occurs under the condition of less than 5%.

In the present invention, it is possible to proceed with consideration of the fuel speed and the shape of the head as additional performance indices, but there may be a limit to include the shape of all the fuel heads.

Next, referring to FIG. 6, the overall configuration of the ultra low nitrogen oxide combustion apparatus 200 according to the second embodiment of the present invention will be described.

Hereinafter, the same components as those of the ultra low nitrogen oxide combustion apparatus 100 according to the first embodiment will not be described in detail and the different parts will be mainly described.

The air multistage sleeve 60 is removed from the ultra low nitrogen oxide combustion apparatus 200 differently from the first embodiment 100 while the recirculation promoting protrusion 90 ' 13).

That is, the oxidant supplied to the outside of the primary fuel injector 10 is totally mixed with the combustion gas passing through the recirculating induction portion 40 without being supplied and separated through the air multi-stage sleeve 60 and flows in the combustion furnace 1 direction do.

As described above, the low NOx combustion apparatus 200 according to the second embodiment differs from the low-NOx combustion apparatus 200 in that the air multistage sleeve 60 is disposed and the recycling promotion protrusion 90 ' And supplies the oxidizing agent and the combustion gas flowing in the combustion furnace 1 through the recirculation inducing unit 40 to the combustion furnace 40 again.

Ultra low nitrogen oxide  Describe the multi-stage combustion process of the combustion device

Next, the multi-stage fuel combustion process of the present invention will be described with reference to FIG.

First, an oxidizing agent is supplied through the oxidizing agent supply part 80, and a part of the supplied oxidizing agent flows through the central oxidizing agent injecting part 85 in the primary fuel injecting body 10. At the same time, fuel is supplied from the fuel supply unit 50 to the primary fuel injection body 10 through the first fuel line 51.

The main fuel flowing in the primary fuel injection body 10 is radially injected through the outer peripheral surface of the enlarged portion 11. The injected main fuel reacts with the oxidant to form a pre- 78 are formed. Here, the enlarged portion 11 has a shape expanding toward the combustion furnace 1, so that the injected fuel can form the premixed region 78 over a wide area.

The pre-mixer formed in the premixed region 78 is discharged to the combustion furnace 1 through the swirler 30 to form the primary space 72. The air supplied to the primary space 72 is analyzed as follows. The pre-mixer formed in the premixed region 78 is transferred into the furnace 1 via the swirler 30 with an axial momentum and a tangential momentum.

In the above process, the combustion gas passing through the recirculation induction unit 40 is supplied to the primary space 72 together with the pre-mixer. The flow rate of the combustion gas discharged from the recirculation inducing portion 40 to the oxidizing agent flow space is increased by the recirculation promoting protrusions 90 so that the flow rate of the combustion gas and the oxidizing agent can be increased while the peeling can be prevented. The premixer and the combustion gas are introduced into the primary space 72 through the above-described process, and are burned to form a stable flame. The primary space 72 is a main flame space area where about 50% or more fuel is injected and combusted.

Next, fuel is supplied from the fuel supply unit 50 to the secondary fuel injection body 20 through the second fuel line 52. [ The auxiliary fuel injected to the upper side of the primary space 72 through the secondary fuel injection body 20 forms a secondary space 74 through a process of reacting with the unreacted oxidant in the primary space 72 . Some of the combustible gas in the primary space 72 mixes with the pre-mixer supplied to the outside of the swirler 30 and moves to the downstream of the primary flame to constitute a flame in a fuel lean state. And the flame in the fuel lean state forms the secondary space 74.

As described above, according to the present invention, the main fuel injected along the radial direction of the primary fuel injector 10 is pre-mixed with the oxidizing agent to form the premixed region 78, The premixer supplied in the combustion chamber 1 forms the primary space 72 and injects auxiliary fuel from the secondary fuel injector 20 into the rear end of the primary space 72 to form the final flame.

As described above, the multistage flame space is formed in the combustion furnace 1 by the fuel injected by the primary fuel injection body 10 and the secondary fuel injection body 20. At the rear end of the primary space 72, a secondary space 74 is created. The secondary space 74 is formed in a shape that surrounds the primary space 72 in a space further entering the inner side of the furnace 1.

On the other hand, in addition to the multi-stage flame space including the first and second spaces 72 and 74, a magnetic recirculation region 76 is formed in the combustion furnace 1. The magnetic recirculation region 76 is formed in the inner edge region of the furnace 1, and the combustion gas can flow in a vortex shape.

The fuel injected from the primary fuel injector 10 forms a primary space 72 which is a stable fuel rich region by the multistage air flow in the combustion furnace 1 and the secondary fuel injected from the secondary fuel injector 20 The injected fuel is partially oxidized by the atmospheric temperature and residual oxygen due to the heat transferred from the primary flame of the primary fuel injector 10 and is converted into various combustible gas species, Thereby forming a secondary space 74 which is a space. Accordingly, the multi-stage flame condition is clearly distinguished in the combustion furnace including the fuel rich region and the fuel lean region.

The flame of the ultra low NOx combustion apparatus 100 to which this principle is applied is basically a form in which the fuel rich region and the fuel lean region are clearly distinguished from each other, minimizing the local high temperature region in the flame and suppressing the production of the thermal NOx as much as possible. In addition, the combustion gas generated in the combustion furnace 1 through the recirculation induction unit 40 flows into the combustion furnace 1 together with the oxidizing agent without requiring any additional power, and reacts with the NOx Generation can be fundamentally reduced.

As described above, the ultra low nitrogen oxide combustion apparatus of the present invention allows the combustion gas generated in the combustion chamber in which the multi-flame field is formed to be transferred without an additional device inside the combustion chamber, not through the external connection passage of the combustion chamber, by applying the internal recirculation technique.

In the present invention, the main fuel is injected in a radial direction or a tangential direction instead of directly injecting the main fuel into the flame in the axial direction of the fuel injection body injected into the combustion furnace, and the pre- By forming the flame-shaped initial flame, it is possible to eliminate the high-temperature reaction zone that was formed in the initial flame of the diffusion flame type in the conventional fuel multi-stage combustor.

In addition, according to the present invention, the combustion gas passing through the recirculation induction unit is supplied again to the combustion furnace along with the oxidizing agent to undergo combustion, thereby increasing the heat capacity of the flame and stably lowering the temperature of the flame.

Although the preferred embodiments of the present invention have been described, the present invention is not limited to the specific embodiments described above. It will be apparent to those skilled in the art that numerous modifications and variations can be made in the present invention without departing from the spirit or scope of the appended claims. And equivalents should also be considered to be within the scope of the present invention.

1: Combustion furnace
10: primary fuel injector
20: secondary fuel injector
30: Swallar
40: recirculation induction part
41: internal recirculating sleeve
43: Connection Guide
45: injection nozzle
47: inclined member
50: fuel supply unit
51: first fuel line
52: Second fuel line
55, 56: Solenoid valve
60: air multistage sleeve
72: primary space
74: Secondary space
76: recirculation zone
78: Premix area
80: oxidant supplier
85: central oxidizing agent spraying part
90: Recirculation promoting protrusion
100: Ultra low nitrogen oxide combustion device

Claims (22)

A primary fuel injector for injecting fuel into the combustion furnace;
A secondary fuel injector disposed at least in the periphery of the primary fuel injector and disposed so that its tip enters the combustion furnace;
A recirculation inducing unit for recirculating the combustion gas generated in the combustion furnace to the combustion furnace by a hydrodynamic force;
A fuel supply unit for supplying fuel to the primary fuel injection body and the secondary fuel injection body;
An oxidant supplier for supplying an oxidant to a space between the primary fuel injector and the secondary fuel injector;
A central oxidant spraying part for spraying the oxidant supplied from the oxidant supply part into the combustion furnace along the inside of the primary fuel spraying body;
An air multistage sleeve disposed to surround the primary fuel injection body for air multistage; And
And a recirculation promoting protrusion laid on an outer surface of the air multistage sleeve,
The oxidant supplied from the oxidant supply unit is supplied in multiple stages through the inner and outer portions of the air multistage sleeve,
Wherein the recirculation promoting protrusion increases the flow rate of the combustion gas flowing between the recirculating induction portion and the air multi-stage sleeve.
Ultra low nitrogen oxide combustion device.
The method according to claim 1,
When the discharge hole diameter of the primary fuel injection body is defined as B, the diameter of the air multistage sleeve is defined as D, and the internal diameter of the recirculation inducing portion is defined as C,
Lt; _{RTI ID} = 0.0 > ₁ , < / RTI >
Ultra low nitrogen oxide combustion device.

3. The method of claim 2,
Characterized in that the value of the first figure of merit is between 0.3 and 0.5.
Ultra low nitrogen oxide combustion device.
The method according to claim 1,
In the ultra low nitrogen oxide combustion apparatus,
And a swirler disposed at a front end of the primary fuel injection body.
Ultra low nitrogen oxide combustion device.
5. The method of claim 4,
When the discharge port diameter of the primary fuel injector is defined as B and the diameter of the swirler as A,
A second figure of merit showing the nozzle shape coefficient, eta _2, is set by the following equation,
Characterized in that the value of the second figure of merit is in the range between 1.5 and 2.0,
Ultra low nitrogen oxide combustion device.

5. The method of claim 4,
The diameter of the discharge port of the primary fuel injection body is B, the diameter of the swirler is A, and the inner diameter of the recirculation inducing portion is C,
A third performance index, < RTI ID = 0.0 > eta ₃ , < / RTI &
And the value of the third figure of merit is in the range of 0.55 to 0.75.
Ultra low nitrogen oxide combustion device.

5. The method of claim 4,
When the distance between the FIR ports is defined as E and the diameter of the fuel pipe is defined as E,
The fourth performance index, < RTI ID = 0.0 > ₄ , < / RTI &
Wherein the value of the fourth figure of merit is in the range of between 45 and 60,
Ultra low nitrogen oxide combustion device.

5. The method of claim 4,
When the discharge port diameter of the primary fuel injection body is defined as B and the inner diameter of the recirculation inducing portion is defined as C,
A fifth performance index, < RTI ID = 0.0 > ₅ , < / RTI &
Wherein the value of the fifth figure of merit is in the range of between 30 and 50,
Ultra low nitrogen oxide combustion device.

delete The method according to claim 1,
Wherein a plurality of the secondary fuel injection bodies are disposed so as to be spaced apart from each other on the same circumference around the primary fuel injection body and the secondary fuel injection body injects fuel in a radial direction thereof ,
Ultra low nitrogen oxide combustion device.
11. The method of claim 10,
Characterized in that the radial injection angle of the secondary fuel injection body injects fuel between an angle toward the adjacent secondary fuel injection body and an angle toward the alternately adjacent secondary fuel injection body,
Ultra low nitrogen oxide combustion device.
11. The method of claim 10,
Characterized in that the fuel from the secondary fuel injection body is injected between 10 DEG and 80 DEG with respect to a plane perpendicular to the axial direction of the secondary fuel injection body.
Ultra low nitrogen oxide combustion device.
11. The method of claim 10,
Wherein the primary fuel injector injects the main fuel supplied thereto in a radial direction and a tangential direction thereof.
Ultra low nitrogen oxide combustion device.
14. The method of claim 13,
The injection speed of the fuel injected through the primary fuel injection body

Characterized in that the fuel is injected between 20 and 50 m / s,
Ultra low nitrogen oxide combustion device.
15. The method of claim 14,
The injection speed of the fuel injected through the secondary fuel injector

Is set to the following formula: < EMI ID =
Ultra low nitrogen oxide combustion device.

11. The method of claim 10,
The recirculating induction unit may include an internal recirculating sleeve disposed to be inclined with respect to the secondary fuel injector, a connecting guide extending from a rear end of the internal recirculating sleeve, and a moving member connected to a rear end of the connecting guide to change a moving direction of the combustion gas Characterized in that it comprises an injection nozzle
Ultra low nitrogen oxide combustion device.
17. The method of claim 16,
Wherein the injection nozzle is disposed obliquely between the primary fuel injection body and the recirculation induction portion to reduce the width between the primary fuel injection body and the recirculation induction portion,
Ultra low nitrogen oxide combustion device.
delete 11. The method of claim 10,
Wherein a tip end of the secondary fuel injection body is further arranged to enter into the combustion furnace as compared with a tip end of the primary fuel injection body.
Ultra low nitrogen oxide combustion device.
11. The method of claim 10,
Wherein the primary fuel injection body forms a primary space which is a fuel rich region inside the combustion furnace and the secondary fuel injection body forms a secondary space which is a fuel lean region at the rear end of the primary space, ≪ / RTI >
Ultra low nitrogen oxide combustion device.
21. The method of claim 20,
The following equation expressing the ratio of the fuel flow rate of the primary fuel injector to the fuel flow rate of the secondary fuel injector is a sixth performance index and η ₆ is a preliminary mixing ratio and is operated in the range of 4 to 22 As a result,
Ultra low nitrogen oxide combustion device.

A method for operating a combustion apparatus according to claim 1,
(a) supplying an oxidant supplied from an oxidant supply through an air multistage sleeve into a combustion furnace;
(b) supplying an oxidant from the oxidant supply unit into the combustion furnace through a central oxidant injection unit;
(c) supplying fuel from the fuel supply unit to the primary fuel injector;
(d) recirculating the combustion gas in the combustion furnace through the recirculation induction portion to the combustion furnace by a hydrodynamic force;
(e) increasing the flow rate of the recirculated combustion gas through the recirculation promoting protrusions;
(f) supplying fuel from the fuel supply unit to the secondary fuel injector; And
(g) forming a multi-stage flame space in the combustion furnace by fuel injected by the primary fuel injection body and the secondary fuel injection body.
A method of operating a combustion device.

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