WO2017209552A1

WO2017209552A1 - Ultra-low emission combustion apparatus

Info

Publication number: WO2017209552A1
Application number: PCT/KR2017/005758
Authority: WO
Inventors: 김세원; 이창엽; 김대해
Original assignee: 한국생산기술연구원
Priority date: 2016-06-03
Filing date: 2017-06-02
Publication date: 2017-12-07
Also published as: KR101822997B1; KR20170137988A

Abstract

The present invention relates to an ultra-low emission combustion apparatus for reducing pollutants, such as nitrogen oxides contained in a combustion gas, through an optimal flame structure and the re-burning of the combustion gas through a structure for supplying fuel of the combustion apparatus and an oxidant, the apparatus comprising: a combustion furnace; a burner having one side inserted into the combustion furnace; a main fuel injector, located at a central portion of the burner, for injecting a main fuel supplied to form a primary flame region in the combustion furnace; a plurality of auxiliary fuel injectors which are positioned so as to surround the periphery of the main fuel injector at predetermined intervals; and a curved portion configured such that an auxiliary fuel injected from the plurality of auxiliary fuel injectors are combined and injected into the combustion furnace, wherein auxiliary fuel supplied to the auxiliary fuel injectors are injected into the combustion furnace along the curved portion while forming a secondary flame region, and the combustion gas generated in the combustion furnace flows along the outer surface of the curved portion to the secondary flame region and is re-burned.

Description

Ultra low pollution combustion device

The present invention relates to a combustion device, and in particular, through the structure of supplying fuel and oxidant of the combustion device to reduce the contaminants such as nitrogen oxides contained in the combustion gas through the optimum flame configuration and recombustion of the combustion gas. An ultra low pollution combustion apparatus.

At present, mankind's main energy source is hydrocarbon-based fossil fuels. However, the problem of environmental pollution by the product after combustion of fossil fuels has been seriously raised. The main environmental pollutants include nitrogen oxides (NOx) and carbon dioxide (CO ₂ ), as well as carbon monoxide (CO) and soot caused by incomplete combustion of fuels.

Combustors using conventional fossil fuels inevitably generate nitrogen oxides (NOx) having a chemical formula of NO and NO2 by chemical reactions during combustion. Low NOx combustion technology to suppress this occurrence is being developed to improve the structure of the combustor, such as the mixture of fuel and air, air-fuel ratio. Nitrogen oxides generated during the combustion process react with other oxygen in the atmosphere, causing environmental problems such as smog and increased ozone in the atmosphere. In particular, emissions from these combustion processes harm the environment and human health, so countries are tightening regulations on more and more stringent standards.

Types of nitrogen oxides may be classified into thermal NOx, prompt NOx, and fuel NOx depending on the cause. 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 produced at the beginning of combustion during the combustion of hydrocarbon-based fuels, and fuel nitrogen oxides are reactions of nitrogen components contained in the fuel. Is generated by Even in such a countermeasure against nitrogen oxides, since gaseous fuels such as natural gas do not contain nitrogen in the fuel, it may be effective to control matters related to Thermal NOx and Prompt NOx.

Nitrogen oxides are known to cause photochemical smog and acid rain and seriously affect plants and animals. For many years, many researchers have studied various ways to reduce NOx.

Because of this, low NOx methods currently being tried include exhaust gas recirculation, water or steam injection, multistage combustion of air and fuel, selective non-catalytic reduction (SNCR), and selective catalytic reduction (SCR). catalytic reduction). Recently, developed countries have tried to re-burn NOx in the post-combustion area, and are known to have high efficiency in terms of NOx reduction rate and economic efficiency.

As a conventional method for reducing NOx as described above, Patent Literature 1 supplies combustion air in three stages by mixing general air and exhaust gas in order to reduce the amount of nitrogen oxides (NOx) generated. By varying the mixing ratios of the two, a three-stage burner for exhaust gas recirculation for liquid and gas is used to minimize the local high temperature generation by multi-stage combustion and to extend the combustion zone to achieve uniform heating in the boiler.

In Patent Document 1, a plurality of exhaust gas supply pipes, a recirculation duct, and a damper are provided as elements for recirculating the exhaust gas so that the exhaust gas is re-introduced into the combustion furnace. Since it needs to be installed separately, there is a disadvantage that the required space increases.

On the other hand, as Patent Document 2, referring to a registered patent filed by the present applicant, as shown in FIG. 4, the combustion gases 3 'and 4' generated in the combustion furnace 1 'are replaced by the combustion furnace. It provides an internal recirculation technology that allows the interior of the burner 2 'to be delivered to the burner 2' without a separate device inside the combustion furnace 1 'but not to an external connection passage, but the combustion gas 4' in some areas within the combustion furnace 1 '. The disadvantage is that it does not use flow effectively.

In addition, the configuration of the peripheral device is not required, but due to the additional configuration for inducing the recirculation of the combustion gas, the combustion device is relatively large in size, for example, a system other than a large specific combustion system such as a water tube boiler. There is a problem that it is difficult to apply.

(Patent Document 1) KR 10-2005-0117417 A

(Patent Document 2) KR 10-1512352 B1

Accordingly, the present invention has been made in view of the above-mentioned conventional problems and solves the problem, through the structure and shape of the combustion apparatus through the stable multi-stage flame formation in the combustion apparatus and effective re-burning of the combustion gas nitrogen oxides It is an object to provide a combustion apparatus that can be reduced.

The present invention to achieve the above object, a combustion furnace; A burner having one side inserted into the combustion furnace; Located in the center of the burner, the main fuel injector for injecting the main fuel supplied to form a primary flame region in the combustion furnace; A plurality of auxiliary fuel injection bodies positioned to surround the main fuel injection body at predetermined intervals; And a curved portion configured to combine and spray the auxiliary fuels injected from the plurality of auxiliary fuel injectors, wherein the auxiliary fuel supplied to the auxiliary fuel injectors is injected into the combustion furnace along the surface of the curved portion. The combustion apparatus forms a secondary flame zone and is combusted, and the combustion gas generated in the combustion furnace flows to the secondary flame zone along the outer surface of the curved portion to be reburned.

And an oxidant supply unit positioned between the main fuel injector and the auxiliary fuel injector, wherein a part of the combustion gas generated in the combustion furnace by the oxidant supplied to the oxidant supply unit is along the inner surface of the curved portion 1. It is desirable to flow to the secondary flame zone and reburn.

A portion of the outer circumferential surface of the line through which the main fuel supplied to the main fuel injector flows is opened, and the oxidant supplied to the oxidant supply unit is injected through the opening by the flow rate of the supplied main fuel. It is preferable to enter the sieve and mix with the main fuel.

One side of the oxidant supply portion extending into the combustion furnace further comprises a recycle induction portion formed between the curved portion and the main fuel injector, the flow rate of the combustion gas is increased by the recycle induction portion in the curved portion It is preferred to flow to the primary flame zone along the side and reburn.

As described above, according to the ultra-low pollution combustion apparatus according to the present invention, by effectively controlling the flow of fuel, oxidant and combustion gas through the configuration and structure of the combustion apparatus, it is possible to promote the mixing of fuel and oxidant and the recombustion of combustion gas. It is possible to reduce the flame composition and the nitrogen oxides, so that complicated peripherals are not installed and the associated costs are not required and the basic combustion system can be maintained.

Therefore, the miniaturization of the combustion apparatus has an advantage that it can be easily applied to various combustion systems.

1 schematically shows an ultra low pollution combustion apparatus according to an embodiment of the present invention.

Figure 2 is a perspective view of the burner of the ultra low pollution combustion apparatus according to an embodiment of the present invention.

3 schematically shows a combustion process of an ultra low pollution combustion apparatus according to an embodiment of the present invention.

4 schematically shows a conventional combustion apparatus.

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

Each component constituting the ultra low pollution combustion apparatus according to the present invention may be used integrally or separately separated as necessary. In addition, some components may be omitted depending on the form of use.

Hereinafter, an ultra low pollution combustion apparatus according to an embodiment of the present invention will be described in detail with reference to the accompanying drawings.

초저공해 연소장치의 전체적인 구성 설명Description of overall composition of ultra low pollution combustion device

First, with reference to Figures 1 and 2 will be described in detail the overall configuration of the ultra-low pollution combustion apparatus according to an embodiment of the present invention.

Ultra low pollution combustion apparatus according to an embodiment of the present invention, the combustion furnace 1, the burner 100, the main fuel injector 10, the auxiliary fuel injector and the curved portion 22.

The combustion furnace 1 is a hollow form in which the space where combustion takes place is provided.

The burner 100 is positioned with a portion of one side inserted into the combustion furnace 1.

The main fuel injector 10 is positioned at the center of the burner 100 to inject the supplied main fuel from the front end into the combustion furnace 1 to be combusted.

A swirler 11 may be provided at the front end of the main fuel injector 10.

On the other hand, the main fuel injector 10 is provided with an opening in which at least a part of the periphery of the line through which the main fuel supplied to the main fuel injector 10 flows.

The auxiliary fuel injectors 20 are provided in plural numbers so as to be spaced apart from each other by a predetermined interval, and the plurality of auxiliary fuel injectors 20 are spaced apart from each other in a radially outward direction around the main fuel injector 10 and thus, the main fuel It is positioned to surround the injection body (10).

And the auxiliary fuel injector 20 injects the auxiliary fuel supplied from the front-end | tip part.

The curved portion 22 is positioned at a tip spaced apart from the tube 21 positioned at the tip portion of the auxiliary fuel injector 20 by a predetermined distance, and communicates with the tip of each auxiliary fuel injector 20. The fuel injected from each of the auxiliary fuel injectors 20 is mixed in the curved portion 22 and the tube 21 and discharged between the spaced portions, and flows along the surface of the curved portion 22 so as to be inside the combustion furnace 1. To be sprayed.

The curved portion 22 includes a curved portion inner surface 24 facing the main fuel injector 10 side, and a curved portion outer surface 23 positioned on the other side thereof.

The oxidant supply unit 30 is located in a partitioned form between the main fuel injector 10 and the auxiliary fuel injector 20, and supplies the oxidant to the front end of each fuel injector through the partitioned space, thereby providing each fuel injector. It is mixed with the fuel injected in the combustion to make the combustion in the furnace (1).

The oxidant supply unit 30 may be divided into two stages through partition walls 31 therein, and each of the main fuel injector 10 and the auxiliary fuel injector 20 through the divided oxidant supply unit 30. The oxidant can be supplied.

Between the oxidant supply part 30 and the front end side of the auxiliary fuel injector 20, one side of the surface 32 which is located on the auxiliary fuel injector 20 side among the surfaces partitioning the space of the oxidant supply part 30 is the combustion furnace. (1) A recirculation induction part 33, which is a space formed by extending to the inner side (a front end side of the auxiliary fuel injector 20) and positioned near the front end of the auxiliary fuel injector 20, is located.

Through this recirculation induction part 33, the space between the oxidant supply part 30 and the auxiliary fuel injector 20 is narrowed, so that the fluid flow rate therebetween is increased.

On the other hand, although not shown, a configuration for supplying fuel to each of the fuel injectors (10, 20) and the configuration for supplying an oxidant to the oxidant supply unit 30 may be provided, the supply amount of these fuels and oxidant valves or dampers It can be adjusted through the control means such as.

초저공해 연소장치의 연소 과정 설명Explanation of combustion process of ultra low pollution combustion device

Hereinafter, the combustion process of the ultra low pollution combustion apparatus according to an embodiment of the present invention will be described in detail with reference to FIG. 3.

The oxidant and the fuel are supplied to the oxidant supply unit 30 and the

respective fuel injectors

10 and 20.

Part of the oxidant supplied to the oxidant supply unit 30 (an oxidant flowing toward the main fuel injector 10 side of the oxidant supply unit 30 divided into the partition walls 31) is supplied to the main fuel injector 10 and injected. Due to the flow of fuel, the fuel is introduced into the main fuel injector 10 through the opening 12 provided in the main fuel injector 10.

This is a process of promoting fuel / oxidant mixing using the Venturi effect. The oxidant introduced into the main fuel injector 10 through the opening 12 is mixed with fuel in a turbulent flow in the main fuel injector 10. .

The main fuel and the oxidant mixed in the main fuel injector 10 are injected into the combustion furnace 1 to form a primary flame region 51 and combust.

At this time, through the swirler 11 provided at the tip of the mixed main fuel injector 10 to be injected into the combustion furnace 1 with axial momentum and tangential momentum. Can be.

The opening 12 facilitates the mixing of fuel and air in the main fuel injector 10, thereby facilitating control of the air-fuel ratio, and obtaining stable flame formation and primary reduction of nitrogen oxides. Can be.

On the other hand, fuel is injected from the tip of the auxiliary fuel injector 20. As described above, the auxiliary fuel supplied to the auxiliary fuel injector 20 is mixed and discharged in the tube 21 and the curved portion 22 and injected into the combustion furnace 1 along the surface of the curved portion 22. do.

This is a coanda (coanda) effect, the coanda effect is a characteristic that shows the tendency for the fluid to be attached to the flow flows, as described above, the auxiliary fuel is injected through the surface of the curved portion 22, the curved surface Low pressure is formed on the surface of the part 22.

The remaining part of the oxidant supplied to the oxidant supply unit 30 (the oxidant flowing toward the auxiliary fuel injector 20 side of the oxidant supply unit 30 divided into the partition walls 31) is supplied to the auxiliary fuel injector 20. And, due to the flow of the auxiliary fuel is injected, it is mixed with the auxiliary fuel on the surface of the curved portion 22 is injected into the combustion furnace (1) to form a secondary flame zone 52 is burned.

Thereby, in the combustion furnace 1, the flame region is formed in the primary and secondary stages by the combustion of the fuel injected by the main fuel injector 10 and the auxiliary fuel injector 20.

Combustion gas generated by the combustion furnace 1 in the flame region as described above flows along the inner surface of the combustion furnace 1 in the combustion furnace 1 toward the tip of the burner 100 under the combustion furnace 1.

The portion 61 of the combustion gas flowing in this way is curved by the auxiliary fuel injector 20 and the curved surface of the auxiliary fuel injector 20 due to the flow rate of the fuel flowing along the curved portion 22 as described above. It flows into the secondary flame zone 52 along the secondary outer surface 23 and is reburned.

Meanwhile, the remaining portion 62 of the combustion gas is returned to the lower portion of the curved portion 22 by the flow rate of the recirculation induction portion 33 and the flowing oxidant between the auxiliary fuel injector 20 and the oxidant supply portion 30 and the recirculation induction portion ( 33 flows into the primary flame zone 51 along the curved inner surface 24 and is reburned.

That is, the combustion gas is subjected to a multi-type induction process in which the recombustion through the curved outer surface 23 and the recombustion through the recirculation induction portion and the curved inner surface 24 are recycled and recycled. Through this configuration, the optimum flame zone in the combustion furnace 1 is formed, and ultra-low pollution combustion is possible by reducing nitrogen oxide contained in the combustion gas generated therefrom through recombustion.

As described above, according to the ultra-low pollution combustion apparatus according to the present invention, by effectively controlling the flow of fuel, oxidant and combustion gas through the configuration and structure of the combustion apparatus, it is optimal to promote the mixing of fuel and oxidant and recombustion of combustion gas. It is possible to reduce the flame composition and the nitrogen oxides, so that no complicated installation and no additional costs are required and the basic combustion system can be maintained.

While preferred embodiments of the present invention have been described above, the present invention is not limited to the above-described specific embodiments. That is, those skilled in the art to which the present invention pertains can make many changes and modifications to the present invention without departing from the spirit and scope of the appended claims, and all such appropriate changes and modifications are possible. Equivalents should be considered to be within the scope of the present invention.

Claims

Combustion furnace 1;

A burner 100 having one side inserted into the combustion furnace 1;

Located in the center of the burner 100, the main fuel injector 10 for injecting the main fuel supplied to form a primary flame region in the combustion furnace (1);

A plurality of auxiliary fuel injectors 20 positioned to surround the main fuel injectors 10 at predetermined intervals; And

And a curved portion 22 configured to combine and spray the auxiliary fuels injected from the plurality of auxiliary fuel injectors 20.

The auxiliary fuel supplied to the auxiliary fuel injectors 20 is injected into the combustion furnace 1 along the surface of the curved portion 22 to be combusted to form a secondary flame region, and the combustion furnace 1 Combustion gas generated in the flow along the outer surface 23 of the curved portion to the secondary flame zone is reburned,

Ultra low pollution combustion device.
The method of claim 1,

Further comprising an oxidant supply unit 30 located between the main fuel injector 10 and the auxiliary fuel injector 20,

Part of the combustion gas generated in the combustion furnace (1) by the oxidant supplied to the oxidant supply unit 30 flows to the primary flame region along the inner surface 24 of the curved portion to be reburned,

Ultra low pollution combustion device.
The method of claim 2,

Further comprising an opening 12 in which a portion of the outer circumferential surface of the line through which the main fuel supplied to the main fuel injector 10 flows, is opened.

The oxidant supplied to the oxidant supply unit 30 by the flow rate of the main fuel supplied into the main fuel injector 10 through the opening 12 is mixed with the main fuel,

Ultra low pollution combustion device.
The method of claim 2,

One side of the oxidant supply unit 30 further includes a recycle induction unit 33 formed between the curved portion 22 and the main fuel injector 10 by extending into the combustion furnace 1,

Flow rate of the combustion gas is increased by the recirculation induction part 33 flows to the primary flame region along the inner surface 24 of the curved part to be reburned,

Ultra low pollution combustion device.