CN218443373U

CN218443373U - Flue gas heating system applied to double-flue SCR

Info

Publication number: CN218443373U
Application number: CN202221554436.1U
Authority: CN
Inventors: 张永和; 张凯; 闫建伟; 毛愷霞; 孙旭东
Original assignee: Beijing Yongbo Cleaning Technology Co ltd
Current assignee: Baotou Steel Group Energy Conservation And Environmental Protection Technology Industry Co ltd
Priority date: 2022-06-21
Filing date: 2022-06-21
Publication date: 2023-02-03
Anticipated expiration: 2032-06-21

Abstract

The utility model discloses a be applied to flue gas heating system in two flues SCR, concretely relates to flue gas heating field, including flue, combustion-supporting air system, fuel gas system and guiding device, the flue is provided with two, the flue configuration is used for heating original flue gas, two flues are constituteed to the flue, the utility model discloses set up the combustor in one side of two flues, the combustor is including arranging the combustion chamber of one side in two flues, and original flue gas in the two flues carries out once heating back through the combustion chamber, mixes with high temperature flue gas in combustion chamber low reaches, realizes the secondary heating, and the flue gas is when eight word boards, opens the hole on eight word boards, reduces the heat and piles up, prevents that eight word boards from deforming, and the blind spot that the flue gas flows reduces, has solved the problem of high temperature between eight word boards and combustion chamber, has increased the security of system operation, has prolonged system life, and the combustor flame flue covers the cross section proportion increase in two flues simultaneously, and CO proportion increases in the burning out the flue gas, and energy-conserving effect is more obvious.

Description

Flue gas heating system applied to double-flue SCR

Technical Field

The utility model relates to a flue gas heating field especially relates to a be applied to flue gas heating system in two flues SCR.

Background

In the industries of steel, metallurgy and coal chemical industry, the smoke discharge amount of a sintering machine is large, the smoke amount of a 500m & lt 2 & gt sintering machine is as high as 1400000Nm & lt 3 & gt/h, the use requirements of large smoke amount cannot be met by the conventional GGH equipment and the like, and two sets of SCR systems are required to run in parallel, namely a double-flue SCR system.

In addition, in the prior art, many SCR adopts a built-in flue gas heating system, the built-in flue gas heating system has flame in a flue, 5000-10000ppm of carbon monoxide exists in the sintering machine flue gas, the carbon monoxide in the flue gas can be ignited by the flame generated by a burner, the heat generated by combustion compensates for part of the heat load of the heating system, and the function of saving fuel can be achieved. The energy saving amount is directly related to the contact ratio of the flue gas and the flame, namely the coverage rate of the flame to the cross section of the flue. Generally, the smaller the cross-sectional area of the flue, the higher the flame coverage, and the better the energy saving effect. For the double-flue SCR heating system, the energy saving rate is superior to that of the traditional arrangement mode.

In addition, compare prior art, combustor upper reaches eight characters board has the optimization, prevents that the flue gas from flowing the blind spot and generating, has strengthened the flue gas circulation in region between eight characters board and the combustion chamber, has solved eight characters board because of the problem that local high temperature leads to deformation, has strengthened the security and the life of flue gas heating system operation.

SUMMERY OF THE UTILITY MODEL

The utility model aims at solving the defects existing in the prior art and providing a flue gas heating system applied to double-flue SCR.

In order to achieve the above purpose, the utility model adopts the following technical scheme:

a flue gas heating system applied to double-flue SCR comprises two flues, a combustion-supporting air system, a fuel gas system and a flow guide device, wherein the two flues are arranged and used for heating original flue gas, the two flues form double flues, two burners are arranged in the flues and used for burning fuel gas, the burners are arranged on the same side of the double flues formed by the two flues, combustion chambers are arranged in the burners, the combustion chambers are arranged at the gas burning positions of the flues, the burners are connected with the flues through the combustion-supporting air system, the combustion-supporting air system comprises a combustion-supporting fan, the combustion-supporting fan is communicated with the flues at the downstream of the burners, and the combustion-supporting air system is used for extracting part of mixed flue gas in the flues or air in the atmosphere into the burners;

the fuel gas system is communicated with the combustor, the fuel gas system is configured to send fuel gas into the combustor, the fuel gas system further comprises an igniter, the igniter extends deep into the combustor, the igniter is configured to ignite the fuel gas in the combustor, the igniter is a plasma igniter, and the fuel gas is blast furnace gas;

the guiding device sets up inside the flue, the guiding device includes diverging device, diverging device sets up the upstream at the combustor, diverging device configuration is used for original flue gas reposition of redundant personnel to first flue gas and second flue gas, the second flue gas is suitable for to flow to between two combustion chambers the low reaches of combustion chamber, first flue gas is suitable for the process the outer wall of combustion chamber, and the combustion chamber low reaches with second flue gas, the high temperature flue gas after having heated mix and form mixed flue gas.

Adopt above-mentioned technical scheme: the second flue gas is subjected to primary heating by a high-temperature field between the combustion chambers and continuously flows to the downstream of the combustion chambers, so that the first flue gas and the second flue gas which are subjected to primary heating are mixed with the high-temperature flue gas which is formed by heating at the downstream of the combustion chambers, and mixed flue gas with uniform temperature is formed.

Preferably, the radial width of the end of the combustion chamber far away from the axis of the flue is smaller than the radial width of the end close to the axis of the flue.

Preferably, the combustion chamber is divided into a conical part and a cylindrical part, and the tail end of the conical part of the combustion chamber extends towards the direction close to the axis of the flue.

Preferably, the included angle between the side projection line of the combustion chamber conical part and the horizontal direction is a, and a is less than or equal to 75 degrees.

Adopt above-mentioned technical scheme: the included angle a between the projection line of the side surface of the tapered part (i.e. the inclined edge of the section of the tapered part shown in the figure) and the horizontal direction of the combustion chamber 135 is less than or equal to 75 degrees, which is beneficial to the full diffusion of flame and fuel gas in the combustion chamber 135 and the full combustion of the fuel gas in the combustion chamber 135, thereby ensuring the high temperature of the wall part of the combustion chamber 135 and the stable and uniform temperature field in the flue 110.

Preferably, the combustion chamber includes one-level combustion chamber and second grade combustion chamber, be provided with one-level heat accumulation ring in the one-level combustion chamber, the one-level combustion chamber configuration is used for the burning of first part fuel gas, the heat that one-level heat accumulation ring configuration is used for absorbing the burning release of first part fuel gas and the heat of firearm release, the second grade combustion chamber sets up the one end that is close to the flue axle center at the combustion chamber and follows axial through connection with the one-level combustion chamber, be provided with second grade heat accumulation ring in the second grade combustion chamber, the combustion that second grade combustion chamber configuration is used for second part fuel gas, second grade heat accumulation ring configuration is used for absorbing the heat of second part fuel gas burning release.

Adopt above-mentioned technical scheme: the secondary heat accumulation ring is suitable for absorbing the heat released by the combustion of the second part of fuel gas and the heat released by the combustion of the first part of fuel gas, and accumulates part of heat to maintain the high temperature of the secondary heat accumulation ring, so that the heat is transferred into the secondary combustion chamber through radiant energy, and the second part of fuel gas in the secondary combustion chamber is ensured to be stably and sufficiently combusted.

Preferably, the igniter extends into the primary combustion chamber, and the igniter is configured to ignite the first portion of the fuel gas in the primary combustion chamber.

Preferably, the burner further comprises a stable combustion blunt body, the stable combustion blunt body is arranged in the primary combustion chamber, and the stable combustion blunt body is configured to be used for printing and dyeing a second part of fuel gas in the secondary combustion chamber.

Adopt above-mentioned technical scheme: after the plasma igniter ignites the first part of fuel gas in the primary combustion chamber, the gas flame in the primary combustion chamber can be diffused through the stable combustion blunt body, so that the second part of fuel gas in the secondary combustion chamber can be ignited.

Preferably, the length L of the flue is in a value range of L being more than or equal to 2.5m.

Adopt above-mentioned technical scheme: can ensure that the flue has sufficient and reasonable space inside.

The utility model has the advantages that:

the utility model discloses one side at double flue sets up the combustor, the combustor is including arranging the combustion chamber of one side in double flue, original flue gas in double flue carries out the primary heating back through the combustion chamber, mix at combustion chamber low reaches and high temperature flue gas, realize the secondary heating, the flue gas is when eight characters board, open a hole on the eight characters board, reduce the heat and pile up, prevent eight characters board deformation, the dead zone that the flue gas flows reduces, the problem of the temperature is too high between eight characters board and combustion chamber has been solved, the security of system operation has been increased, the system life has been prolonged, the combustor flame covers flue cross section proportion and increases in the double flue simultaneously, CO proportion increases in the loss of burning flue gas, energy-saving effect is more obvious.

Drawings

Fig. 1 and 2 are schematic diagrams of the mechanism of the present invention;

fig. 3 is a schematic view of the structure of the combustion chamber.

Illustration of the drawings: 110. a flue; 130. a burner; 131. a cabinet housing; 133. stably burning the bluff body; 135. a combustion chamber; 136. a primary combustion chamber; 137. a secondary combustion chamber; 138. a primary heat storage ring; 139. A secondary heat storage ring; 140. a fuel gas system; 150 a flow directing device; 160. an igniter; 170. A combustion air system; 175 a combustion fan;

Detailed Description

The technical solutions in the embodiments of the present invention will be described clearly and completely with reference to the accompanying drawings in the embodiments of the present invention, and it is obvious that the described embodiments are only some embodiments of the present invention, not all embodiments.

As shown in fig. 1, a flue gas heating system applied to a double-flue SCR includes a flue 110, the flue 110 is formed by radially widening an existing flue, raw flue gas, that is, low-temperature flue gas discharged by a sintering machine and other equipment, is introduced upstream of the flue 110, and is required to be heated so that the flue gas reaches a temperature required by a subsequent SCR denitration treatment and other process, at least two burners 130 are oppositely arranged on two sides of the flue 110, in other words, the flue gas heating system includes an even number of burners 130, at least two burners 130 are included, every two burners 130 are oppositely arranged on two sides of the flue, each burner 130 is provided with a combustion chamber 135, and the combustion chambers 135 are arranged inside the flue 110, so that every two corresponding combustion chambers 135 are located on two opposite sides in the flue 110.

The burner 130 extends into the flue 110 from the outside of the flue 110, the combustion chamber 135 is located inside the flue 110, the casing 131 of the burner 130 is arranged outside the flue 110, the casing of the burner 130 is coaxially arranged with the corresponding combustion chamber 135, it should be noted that the burner 130 is suitable for being introduced with fuel gas such as blast furnace gas or coke oven gas, etc., and the combustion of the fuel gas is performed in the combustion chamber 135, and the heat released by the combustion of the fuel gas is absorbed by the wall of the combustion chamber 135, so that the wall of the combustion chamber 135 is in a high temperature state, and the heat can be dissipated to the periphery of the combustion chamber 135 by radiation, and a high temperature field can be formed between every two opposite combustion chambers 135 in the flue 110, so that when the original flue gas passes through the combustion chamber 135, the flue gas can be heated both by passing through the wall of the combustion chamber 135 and passing between the two opposite combustion chambers 135, and the flue gas after heating is mixed in the area downstream of the combustion chamber 135, and the temperature is uniformly mixed flue gas, and the design is a low temperature secondary heating process.

Wherein, every two corresponding combustors 130 are arranged on two sides of the flue 110 in an opposite manner, and by arranging every two combustors 130 in an opposite manner, the flame in one combustor 130 opposite to the combustor can be effectively supported, the disturbance and mixing of flue gas flow in the flue 110 can be enhanced, the uniformity of a temperature field in the flue 110 is ensured, the heating and mixing of flue gas in the flue 110 are more uniform, and the overall temperature level of the heated flue gas is ensured.

The wall of the combustion chamber 135 is made of heat-resistant stainless steel, and the heat-resistant temperature T of the stainless steel is T360CTC. Through the combustion chamber that adopts heat-resisting stainless steel, can prevent effectively that microthermal original flue gas air current from influencing the flame in the combustor 130 when through combustor 130 to guarantee catching fire and the stable combustion of the fuel gas in the combustor 130, moreover, the scouring of original flue gas air current can reduce the wall temperature of combustion chamber 135, helps prolonging the life of combustion chamber 135.

As shown in fig. 1, each burner 130 is provided with an independent fuel gas system 140, the fuel gas system 140 is communicated with the corresponding burner 130 through a pipeline, so that fuel gas can be fed into the burner 130, wherein each burner 130 further comprises an igniter 160, and the igniter 160 extends into the burner 130, so that the fuel gas in the burner 130 can be ignited through the igniter 160, and the combustion of the fuel gas in the combustion chamber 135 is realized.

Because the burner 130 of the present invention generally adopts a blast furnace gas burner or a coke oven gas burner, the fuel gas introduced into the fuel gas system 140 is blast furnace gas or coke oven gas. Blast furnace gas or coke oven gas are poor fuel gas, so that unstable combustion is easily caused. Therefore, the igniter 130 is preferably a plasma igniter having a combustion tracing function capable of performing combustion tracing when the combustion of the fuel gas in the burner 130 is unstable, thereby ensuring stable combustion of the fuel gas.

As shown in fig. 1, the flue gas heating system further includes a combustion air system 170 connected to the burner 130, and combustion-supporting flue gas or air can be introduced into the burner 130 through the combustion air system 170, the flue gas and air will enter the combustion chamber 135 and combust with the fuel gas in the combustion chamber 135, so as to facilitate the ignition and more complete combustion of the fuel gas, it should be noted that one end of the combustion air system 170 is connected to the flue 110, and particularly, is communicated with the area of the flue 110 downstream of the burner 130, and the combustion air system 170 is provided with a separate air inlet, so that the mixed flue gas in the flue 110 or air in the atmosphere can be extracted and introduced into the burner 130.

The combustion-supporting air system 170 includes a combustion-supporting air blower, the combustion-supporting air blower is communicated with the flue 110 area downstream of the burner 130, on one hand, when using flue gas for combustion supporting, the combustion-supporting air blower 175 is used as an induced draft fan, and the combustion-supporting air blower 175 is adapted to extract and introduce part of the mixed flue gas in the flue 110 into the burner 130, so that ignition and combustion of fuel gas in the burner 130 are assisted by the mixed flue gas, and since the combustion-supporting flue gas is the mixed flue gas extracted from the flue 110, the total amount of the mixed flue gas in the flue 110 is controlled, and the mixed flue gas in the flue 110 is prevented from increasing too fast and too high, so that the pressure head of the flue gas in the flue 110 increased within a certain time is small, thereby avoiding the problem of insufficient induced draft fan output, and making the heating process of the flue gas more stable, on the other hand, when using air for combustion supporting, the combustion-supporting air blower 175 is adapted to extract air from the atmosphere and feed air into the burner 130, so as to provide oxygen for ignition and combustion of the combustion in the burner 130, and not only assist the ignition and stable combustion of the combustion-supporting air in the flue gas in the combustion of the burner 130, but also to maintain the high-supporting air pressure state, and avoid explosion of the fuel gas, and maintain the negative pressure of the high pressure of the flue 110 all the high pressure.

In addition, the combustion-supporting air system 170 is further provided with a control valve, and the speed of the flue gas or air introduced into the combustor 130 by the combustion-supporting air system 170 can be controlled by the control valve, so that the reasonable regulation and control of the amount of the introduced flue gas or air according to the combustion condition in the combustion chamber 135 are facilitated.

In addition, a diversion device 150 is further disposed in the flue 110, and the diversion device 150 is adapted to divert the raw flue gas in the flue 110 so that part of the raw flue gas passes through the outer wall of the combustion chamber 135 (i.e. flows through the outer wall of the combustion chamber 135) to perform primary heating, and specifically, the diversion device 150 includes a diversion device disposed in an upstream region of the flue 110 relative to the combustion chamber 135. When the original flue gas flows into the flow guiding device 150, the original flue gas is firstly divided by the flow dividing device, and part of the divided original flue gas flows through the outer wall of the combustion chamber 135, the high temperature of the wall of the combustion chamber 135 can heat the part of the original flue gas for the first time, the flue gas after the first heating continuously flows to the flue region at the downstream of the combustion chamber 135, after the original flue gas in the flue 110 is divided, at least two first flue gases corresponding to the combustion chamber 135 are formed, and a strand of second flue gas is also formed by the division, wherein each strand of the first flue gas is suitable for being heated once through the outer wall of the combustion chamber 135 and then flows to the downstream of the combustion chamber 135, the second flue gas directly flows between the two opposite combustion chambers 135 along the axial direction of the flue 110, and in this design, the second flue gas can be heated once by the high temperature field between the combustion chambers 135, the first flue gas and the second flue gas after the primary heating are mixed with the high-temperature flue gas formed by heating at the downstream of the combustion chamber 135, so that mixed flue gas with uniform temperature is formed, and the flue gas mixing process is also a secondary heating process, it should be noted that the heating treatment of the flue gas heating system 100 on the original flue gas is a continuous process, so that the high-temperature flue gas formed by mixing after heating already exists in the area located at the downstream of the combustion chamber 135 in the flue 110, and thus the first flue gas and the second flue gas after the primary heating can be mixed with the high-temperature flue gas existing at the downstream of the combustion chamber 135 after flowing to the downstream of the combustion chamber 135, so that the secondary heating is realized during mixing, and the mixed flue gas with uniform temperature is formed.

The combustion chamber 135 is provided with two, and two burners 130 are arranged oppositely on both sides of the flue 110. The flow dividing device is adapted to divide the original flue gas into two first flue gases and one second flue gas, wherein the two first flue gases respectively pass through the outer walls of the two opposite combustion chambers 135 and then flow downstream of the combustion chambers 135, and the second flue gas directly flows between the two opposite combustion chambers 135 along the axial direction of the flue 110 and flows downstream of the combustion chambers 135.

As shown in FIG. 1, the radial width of the combustion chamber 135 at the end away from the axis of the flue is less than the radial width at the end near the axis of the flue, and the diameter and axial length of the combustion chamber 135 are related to the power of the burner 130. Specifically, the combustion chamber 130 includes a tapered portion and a cylindrical portion, wherein the cylindrical portion is formed by extending a tail end (an end having a larger diameter) of the tapered portion toward a direction close to the axis of the flue.

Wherein, the included angle between the projection line of the side surface of the conical part (i.e. the oblique side of the section of the conical part shown in the figure) and the horizontal direction is set as a, and the value range of the included angle a is less than or equal to 75 degrees. With such a design, the arrangement of the combustion chamber 135 is beneficial to the full diffusion of flame and fuel gas in the combustion chamber 135 and the full combustion of the fuel gas in the combustion chamber 135, thereby ensuring the high temperature of the wall of the combustion chamber 135 and the stable and uniform temperature field in the flue 110.

As shown in fig. 2, the combustion chamber 135 includes a primary combustion chamber 136 and a secondary combustion chamber 137 which are coaxially disposed and penetrate, and the primary combustion chamber 136 and the secondary combustion chamber 137 are arranged in the direction in which the fuel gas flows, that is, the secondary combustion chamber 137 is disposed at one end near the axial center of the flue 110. Specifically, the secondary combustion chamber 137 includes the above-described tapered portion and the cylindrical portion, and the tapered portion of the secondary combustion chamber 137 is annularly provided outside the primary combustion chamber 136. In addition, the sidewall ring of the primary combustion chamber 136 is provided with a primary heat accumulating ring 138, and the sidewall ring of the secondary combustion chamber 137 is provided with a secondary heat accumulating ring 139.

In an embodiment of the present invention, the fuel gas is divided into two paths (i.e. into a first portion fuel gas and a second portion fuel gas) to enter the combustor 130 for combustion. Specifically, a first portion of the fuel gas is introduced into the primary combustion chamber 136 as an ignition fuel and is adapted to be combusted in the primary combustion chamber 136; the second portion of the fuel gas is introduced into the secondary combustion chamber 137 as the primary fuel and is adapted to be combusted in the secondary combustion chamber 137. First, a first portion of the fuel gas in the primary combustion chamber 136 is ignited by the plasma igniter 160, and then the flame energy of the combustion of the first portion of the fuel gas is diffused to ignite a second portion of the fuel in the secondary combustion chamber 137.

The primary heat accumulation ring 138 is adapted to absorb heat released by the combustion of the first portion of fuel gas and heat generated by the ignition of the plasma igniter 160, and accumulate a portion of the heat to maintain a high temperature of the primary heat accumulation ring 138, thereby ensuring stable combustion of the first portion of fuel gas. The secondary heat accumulation ring 139 is adapted to absorb heat released by combustion of the second portion of fuel gas and heat released by combustion of the first portion of fuel gas, and accumulate a portion of the heat to maintain a high temperature of the secondary heat accumulation ring 139, thereby transferring the heat into the secondary combustion chamber 137 by radiant energy, and ensuring stable and sufficient combustion of the second portion of fuel gas in the secondary combustion chamber 137.

Further, the burner 130 further includes a stable combustion blunt 133, and when the plasma igniter 160 ignites the first portion of the fuel gas in the primary combustion chamber 136, the gas flame in the primary combustion chamber 136 can be diffused by the stable combustion blunt 133, thereby igniting the second portion of the fuel gas in the secondary combustion chamber 137.

Through the arrangement, the fuel gas in the combustion chamber 135 can be ensured to be fully and stably combusted to release heat, so that the wall of the combustion chamber 135 can be maintained in a stable high-temperature state, the uniformity and stability of a temperature field in the flue 110 can be maintained, the flue gas in the flue 110 can be fully heated and uniformly mixed, and the temperature required by the subsequent process can be reached.

The total length L of the flue 110 is not less than 2.5m, i.e., L32.5m. The distance of the flow dividing device from the burner 130 is about l-5m. Therefore, the full and reasonable space in the flue 110 can be ensured, the guide device 150 and the combustion chamber 135 of the flue heating system 100 can be reasonably arranged, and the processes of shunting, primary heating and mixed secondary heating of flue gas can be ensured to be smoothly carried out.

The above, only be the concrete implementation of the preferred embodiment of the present invention, but the protection scope of the present invention is not limited thereto, and any person skilled in the art is in the technical scope of the present invention, according to the technical solution of the present invention and the utility model, the concept of which is equivalent to replace or change, should be covered within the protection scope of the present invention.

Claims

1. A flue gas heating system applied to double-flue SCR (selective catalytic reduction) comprises two flues (110), a combustion-supporting air system (170), a fuel gas system (140) and a flow guide device (150), and is characterized in that the flues (110) are provided with two flues, the flues (110) are configured for heating original flue gas, the two flues (110) form the double flues, two burners (130) are arranged in each flue (110), the burners (130) are configured for burning fuel gas, the burners (130) are arranged on the same side of the double flues formed by the two flues (110), a combustion chamber (135) is arranged in each burner (130), the combustion chamber (135) is arranged at the gas burning position of the flues (110), the burners (130) are connected with the flues (110) through the combustion-supporting air system (170), the combustion-supporting air system (170) comprises a combustion-supporting fan, the fan is communicated with the flues (110) at the downstream of the burners (130), and the combustion-supporting air system (170) is configured for mixing part of the flue gas in the flues (110) or extracting air in the atmosphere into the combustion-supporting air;

the fuel gas system (140) is communicated with the combustor (130), the fuel gas system (140) is configured to send fuel gas into the combustor (130), the fuel gas system (140) further comprises an igniter (160), the igniter (160) extends into the combustor (130), the igniter (160) is configured to ignite the fuel gas in the combustor (130), the igniter (160) is a plasma igniter (160), and the fuel gas is blast furnace gas;

the utility model discloses a flue gas mixing device, including burner (130), guiding device (150), diverging device set up the upstream at burner (130), diverging device configuration is used for original flue gas reposition of redundant personnel to first flue gas and second flue gas, the second flue gas is suitable for from two combustion chambers (135) between to flow to the low reaches of combustion chamber (135), first flue gas is suitable for the process the outer wall of combustion chamber (135), and combustion chamber (135) low reaches with second flue gas, the high temperature flue gas after having heated mix and form mixed flue gas.

2. The system of claim 1, wherein the combustion chamber (135) has a smaller radial width at the end away from the axis of the flue (110) than at the end close to the axis of the flue (110).

3. The flue gas heating system applied to the double-flue SCR of claim 1, wherein the combustion chamber (135) is divided into a conical part and a cylindrical part, and the tail end of the conical part of the combustion chamber (135) extends towards the direction close to the axial center of the flue (110).

4. The flue gas heating system applied to the double-flue SCR of claim 1, wherein the included angle between the side projection line of the conical part of the combustion chamber (135) and the horizontal direction is a, and a is less than or equal to 75 degrees.

5. The flue gas heating system applied to the double-flue SCR of claim 1, wherein the combustion chamber (135) comprises a primary combustion chamber (136) and a secondary combustion chamber (137), a primary heat accumulation ring (138) is arranged in the primary combustion chamber (136), the primary combustion chamber (136) is configured for combusting a first part of the fuel gas, the primary heat accumulation ring (138) is configured for absorbing heat released by the combustion of the first part of the fuel gas and heat released by the igniter (160), the secondary combustion chamber (137) is arranged at one end, close to the axial center of the flue (110), of the combustion chamber (135) and is in through connection with the primary combustion chamber (136) along the axial direction, a secondary heat accumulation ring (139) is arranged in the secondary combustion chamber (137), the secondary combustion chamber (137) is configured for combusting a second part of the fuel gas, and the secondary heat accumulation ring (139) is configured for absorbing heat released by the combustion of the second part of the fuel gas.

6. The system of claim 1, wherein the igniter (160) extends into the primary combustion chamber (136), the igniter (160) configured to ignite the first portion of the fuel gas in the primary combustion chamber (136).

7. The flue gas heating system for use in a dual stack SCR of claim 1, wherein said burner (130) further comprises a flame stabilizing blunt disposed within the primary combustion chamber (136), said flame stabilizing blunt configured to dye a second portion of the fuel gas in the secondary combustion chamber (137).

8. The flue gas heating system applied to the double-flue SCR of claim 1, wherein the length L of the flue (110) is in a range L being larger than or equal to 2.5m.