CN219244308U

CN219244308U - Radiant tube heating device

Info

Publication number: CN219244308U
Application number: CN202223179576.8U
Authority: CN
Inventors: 周军; 丹尼斯·奎恩; 周佳敏
Original assignee: Fafu Cryogenic Equipment Suzhou Co ltd
Current assignee: Fafu Cryogenic Equipment Suzhou Co ltd
Priority date: 2022-11-29
Filing date: 2022-11-29
Publication date: 2023-06-23
Anticipated expiration: 2032-11-29

Abstract

The utility model relates to a radiant tube heating device, which comprises a preheater, a burner and a radiant tube, wherein an air channel and a flue gas channel are arranged in the preheater, air and flue gas exchange heat in the preheater, and preheated air is introduced into the burner through a preheated air pipeline; after the flue gas passes through the preheater, one part of the flue gas is discharged through a flue gas outlet, and the other part of the flue gas enters the burner through a flue gas return pipeline; the burner comprises a fuel gas inlet and a combustion area, and the fuel gas inlet, a preheated air pipeline and a flue gas reflux pipeline are respectively communicated with the combustion area. The application adopts the flue gas reflux technology on one hand, reduces the emission value of nitrogen oxides, on the other hand, the flue gas is utilized to preheat the combustion air, so that the energy utilization rate is improved, and the balance between emission and energy conservation is achieved.

Description

Radiant tube heating device

Technical Field

The utility model relates to the field of heat exchange equipment, in particular to a radiant tube heating device.

Background

In the metal heat treatment industry, radiant tubes are typically used to indirectly heat a workpiece, and natural gas is often used as a primary fuel for combustion during the process. When the combustion temperature is higher than 850 ℃, oxygen and nitrogen in the flue gas can combine to form a series of nitrogen oxides (NOx), and the nitrogen oxides are main factors of environmental pollution such as haze and acid rain in the atmosphere. Therefore, how to provide a radiant tube heating device capable of reducing nitrogen oxide emissions and maintaining combustion thermal efficiency is a technical problem to be solved by those skilled in the art.

Disclosure of Invention

The utility model provides a radiant tube heating device to solve the technical problems.

In order to solve the technical problems, the utility model provides a radiant tube heating device which comprises a preheater, a burner and a radiant tube,

an air channel and a flue gas channel are arranged in the preheater, air and flue gas exchange heat in the preheater, and preheated air is introduced into the burner through a preheated air pipeline; after the flue gas passes through the preheater, one part of the flue gas is discharged through a flue gas outlet, and the other part of the flue gas enters the burner through a flue gas return pipeline;

the burner comprises a fuel gas inlet and a combustion area, and the fuel gas inlet, a preheated air pipeline and a flue gas reflux pipeline are respectively communicated with the combustion area.

Preferably, the preheater comprises a shell, a finned tube and a central tube which are sequentially arranged from outside to inside along the radial direction, wherein one end of the finned tube, which is close to the radiant tube, is closed and provided with a head, and a gap is reserved between one end of the central tube, which is close to the radiant tube, and the head.

Preferably, a plurality of fins are arranged on the fin tube, and the fins are respectively arranged on the inner side and the outer side of the tube wall of the fin tube.

Preferably, the air passage includes an inner space of the center tube and a space between the center tube and the fin tube, and the flue gas passage includes a space between the outer shell and the fin tube.

Preferably, the burner further comprises a mixing area, the preheated air pipeline and the flue gas reflux pipeline are communicated with the mixing area, and part of the preheated air and the reflux flue gas are mixed in the mixing area to obtain an air flue gas mixture.

Preferably, the combustion area is divided into a first combustion area, a second combustion area and a third combustion area, and the fuel gas introduced by the fuel gas inlet and part of the preheated air introduced in the preheated air pipeline are mixed and combusted in the first combustion area; the second combustion zone is positioned downstream of the first combustion zone, and combustion products of the first combustion zone are mixed with a portion of the air-flue gas mixture and combusted in the second combustion zone; the third combustion zone is downstream of the second combustion zone, and the combustion products of the second combustion zone are mixed with another portion of the air-flue gas mixture and combusted in the third combustion zone.

Preferably, the burner further comprises a secondary combustion device, the second combustion area is arranged in the secondary combustion device, and the secondary combustion device comprises a cylinder wall and an end plate arranged at one end of the cylinder wall.

Preferably, a first hole communicated with the first combustion area is formed in the middle of the end plate, and combustion products of the first combustion area flow to the second combustion area through the first hole; a plurality of second holes communicated with the mixing area are distributed around the first holes, and a part of air-flue gas mixture flows to a second combustion area through the second holes; another portion of the air-flue gas mixture then flows to the third combustion zone via the outside of the secondary combustion device.

Preferably, a flow control mechanism is arranged in the flue gas return pipeline and/or the preheated air channel.

Preferably, the burner is constructed in an integral manner.

Compared with the prior art, the radiant tube heating device provided by the utility model has the following advantages:

1. according to the method, on one hand, a flue gas reflux technology is adopted, so that the emission value of nitrogen oxides is reduced, on the other hand, the flue gas is utilized to preheat combustion air, and the energy utilization rate is improved;

2. the utility model divides the combustion in the burner into three areas for staged combustion, thereby inhibiting the generation of nitrogen oxides.

Drawings

FIG. 1 is a schematic perspective view of a radiant tube heating device according to an embodiment of the present utility model;

FIG. 2 is a cross-sectional view of a preheater in an embodiment of the present utility model;

FIG. 3 is a cross-sectional view of a burner in one embodiment of the utility model;

fig. 4 is a schematic perspective view of a secondary combustion device according to an embodiment of the present utility model.

In the figure: 100-preheater, 101-combustion air inlet, 102-flue gas outlet, 110-housing, 120-finned tube, 121-tip, 122-fin, 130-center tube, 200-burner, 201-gas inlet, 210-first combustion zone, 220-second combustion zone, 230-third combustion zone, 240-mixing zone, 250-secondary combustion device, 251-cylinder wall, 252-end plate, 253-first hole, 254-second hole, 300-radiant tube, 410-preheated air duct, 420-flue gas return duct.

Detailed Description

In order to describe the technical solution of the above utility model in more detail, the following specific examples are listed to demonstrate technical effects; it is emphasized that these examples are illustrative of the utility model and are not limiting the scope of the utility model.

The radiant tube heating device provided by the utility model, as shown in fig. 1 to 3, comprises a preheater 100, a burner 200 and a radiant tube 300, wherein an air channel and a flue gas channel are arranged in the preheater 100, combustion air is introduced into the inlet of the air channel, that is, the inlet of the air channel is a combustion air inlet 101, and the outlet of the air channel is communicated with a preheated air pipeline 410. The inlet of the flue gas channel is communicated with the radiant tube 300 for introducing flue gas, and the outlet is communicated with the flue gas outlet 102 and the flue gas return pipeline 420. The burner 200 comprises a gas inlet 201 and a combustion zone, with which the gas inlet 201, the preheated air duct 410 and the flue gas return duct 420 are in communication, respectively. In this way, a part of the flue gas in the radiant tube 300 is directly discharged from the flue gas outlet 102, and the other part flows into the burner 200 again through the flue gas return pipe 420 to participate in combustion, so as to achieve the purpose of reducing emission. After entering the preheater 100, the combustion air exchanges heat with the high-temperature flue gas entering the preheater 100, and the waste heat of the flue gas is utilized to preheat the combustion air, so that the combustion air can be preheated to about 300 ℃, the exhaust temperature of the flue gas can be reduced, the temperature of the combustion air can be increased to be beneficial to combustion of fuel gas, and the utilization rate of energy sources is greatly improved.

In some embodiments, referring to fig. 2, the preheater 100 includes a casing 110, a fin tube 120 and a central tube 130 sequentially disposed from outside to inside in a radial direction, wherein the fin tube 120 is sleeved on the outer side of the central tube 130, one end of the fin tube 120 near the radiant tube 300 is closed and has a tip 121, and a gap is formed between one end of the central tube 130 near the radiant tube 300 and the tip 121, so that air can flow to a circumferential channel between the fin tube 120 and the central tube 130 after being diverted from the central tube 130 at the tip 121 via the gap. In some embodiments, a plurality of fins 122 are provided on the finned tube 120, the fins 122 being provided on the inside and outside of the tube wall of the finned tube 120, respectively, i.e., a portion of the fins 122 are provided in the flue gas channel and a portion of the fins 122 are provided in the air channel; by providing the fins 122 in the flue gas passage and the air passage, the heat exchange area can be increased, and the heat exchange capacity can be improved.

The flue gas channel is a space between the housing 110 and the finned tube 120 or a space between the housing 110 and the radiant tube 300 and the finned tube 120. Specifically, the flow of flue gas is indicated by solid arrows in fig. 2, namely: the flue gas flows from the radiant tube 300 to the preheater 100, is blocked by the end 121, is dispersed to the periphery, and flows through the fins 122 to release heat, wherein one part of the heat is discharged from the flue gas outlet 102, and the other part of the heat flows into the flue gas return channel 420 to participate in subsequent combustion. And the air passage is the inner space of the center tube 130 and the space between the center tube 130 and the fin tube 120. Specifically, the flow of combustion air is indicated by the dashed arrows in fig. 2, namely: the combustion air introduced from the combustion air inlet 101 flows along the central tube 130, turns after being blocked by the end head 121, flows reversely along the space between the central tube 130 and the finned tubes 120, flows into the preheating air channel 410 through the gaps formed between the outer surface of the central tube 130 and the inner surface of the finned tubes 120, and realizes heat exchange between air and flue gas in the process, thereby completing preheating.

In some embodiments, a flow control mechanism (not shown) is disposed in the flue gas recirculation pipe 420 to adjust the flue gas recirculation amount according to actual requirements; of course, a flow control mechanism (not shown) may also be provided in the preheated air channel 410 to adjust the air flow according to actual demand. In some embodiments, the flow control mechanism may employ a valve.

In some embodiments, referring to fig. 3, the burner 200 includes a mixing area 240, and the preheated air duct 410 and the flue gas recirculation duct 420 are in communication with the mixing area 240 to allow a portion of the combustion air to be thoroughly mixed with the recirculated flue gas in the mixing area 240 to obtain a mixture of combustion air and recirculated flue gas. The combustor 200 also includes a secondary combustion device 250, the secondary combustion device 250 being connected to upstream components by a combustion can.

As shown in fig. 3, the combustion zone is divided into a first combustion zone 210, a second combustion zone 220, and a third combustion zone 230. Specifically, the gas introduced from the gas inlet 201 and a part of the air introduced from the preheated air duct 410 are introduced into the first combustion zone 210, and the two gases are mixed in the first combustion zone 210 and ignited by the ignition gun, and of course, are ignited by the flame in the first combustion zone 210 when the burner 200 is operating normally, and the gas is in an excessive state, which is referred to herein as a first combustion product, and a part of the first combustion product is still unburned. The first combustion products flow to the downstream second combustion zone 220 via the combustion cans, the second combustion zone 220 is located inside the secondary combustion device 250, and the second combustion zone 220 also comprises a part of the mixed gas of combustion air and return flue gas, the part of the mixed gas of combustion air and return flue gas is mixed with the first combustion products in the secondary combustion device 250, and the second combustion products are obtained after continuing to burn in the second combustion zone 220, and the second combustion products are still in a gas excess state. The third combustion zone 230 is located in a region adjacent to the outlet of the secondary combustion device 250; the other portion of the combustion air and recirculated flue gas mixture does not pass into the secondary combustion device 250 but bypasses the secondary combustion device 250 and is mixed with the second combustion products in the third combustion zone 230 and combusted (as indicated by the outer dashed arrow in fig. 3). Through setting up the tertiary combustion area that the tandem arrangement in proper order for the gas can be in tertiary combustion area in proper order burn step by step, realizes fully burning, can reduce nitrogen oxide's emission greatly in the time, can also improve combustion efficiency.

In some embodiments, referring to fig. 4, the second combustion zone 220 is disposed in a cylindrical secondary combustion device 250, the secondary combustion device 250 includes a cylinder wall 251 and an end plate 252 disposed at one end of the cylinder wall 251, the end plate 252 is disposed at one end of the secondary combustion device 250 located in the mixing zone 240, and a secondary combustion device outlet is disposed at one end of the secondary combustion device 250 located in the radiant tube 300. The secondary combustion device 250 is used to construct an isolated secondary combustion zone and functions to stabilize the flame.

In some embodiments, referring to fig. 4, a first hole 253 is formed in the middle of the end plate 252 and is in communication with the first combustion area 210, a plurality of second holes 254 are distributed around the first hole 253 and are in communication with the mixing area 240, a part of the mixture of the combustion air and the recirculated flue gas flows into the secondary combustion device 250 through the second holes 254, and another part of the mixture of the combustion air and the recirculated flue gas flows into the third combustion area 230 through the outside of the secondary combustion device 250.

In addition, the burner 200 may be integrated into a single casting, so as to increase the integration level of the burner and reduce the manufacturing cost of the burner 200.

In some embodiments, both the pre-heat air duct 410 and the flue gas recirculation duct 420 employ hoses, thereby avoiding limitations of the rigid connection to the accuracy of the installation.

In summary, the radiant tube heating apparatus provided by the present utility model includes the preheater 100, the burner 200 and the radiant tube 300, wherein an air channel and a flue gas channel are provided in the preheater 100, the air and the flue gas exchange heat in the preheater, the temperature of the flue gas is reduced, the temperature of the air is increased at the same time, the preheated air is introduced into the burner 200 through the preheated air pipe 410, and a part of the flue gas is introduced into the burner 200 through the flue gas return pipe 420. The burner 200 is provided with the three-stage combustion area, so that the fuel gas can be mixed with air and the return flue gas, and the fuel gas is fully combusted, thereby improving the energy utilization rate and reducing the nitrogen oxide content in the flue gas.

It will be apparent to those skilled in the art that various modifications and variations can be made to the present utility model without departing from the spirit or scope of the utility model. Thus, it is intended that the present utility model also include such modifications and alterations insofar as they come within the scope of the appended claims or the equivalents thereof.

Claims

1. A radiant tube heating device is characterized by comprising a preheater, a burner and a radiant tube,

2. The radiant tube heating apparatus as claimed in claim 1, wherein the preheater comprises a housing, a finned tube and a center tube disposed in order from outside to inside in a radial direction, the finned tube being closed at one end thereof adjacent to the radiant tube and having a tip, and the center tube being provided at one end thereof adjacent to the radiant tube with a gap therebetween.

3. The radiant tube heating apparatus as claimed in claim 2, wherein a plurality of fins are provided on the fin tube, the plurality of fins being provided on the inner side and the outer side of the tube wall of the fin tube, respectively.

4. The radiant tube heating apparatus of claim 2, wherein the air passage comprises an interior space of the center tube and a space between the center tube and the fin tube, and the flue gas passage comprises a space between the housing and the fin tube.

5. The radiant tube heating apparatus of claim 1 wherein the burner further comprises a mixing zone, the preheated air conduit and the flue gas return conduit being in communication with the mixing zone, a portion of the preheated air being mixed with the return flue gas in the mixing zone to produce an air-flue gas mixture.

6. Radiant tube heating apparatus as claimed in any one of claims 1 to 5 wherein the combustion zone is divided into a first combustion zone, a second combustion zone and a third combustion zone, the gas introduced at the gas inlet and part of the preheated air introduced in the preheated air duct being mixed and combusted in the first combustion zone; the second combustion zone is positioned downstream of the first combustion zone, and combustion products of the first combustion zone are mixed with a portion of the air-flue gas mixture and combusted in the second combustion zone; the third combustion zone is downstream of the second combustion zone, and the combustion products of the second combustion zone are mixed with another portion of the air-flue gas mixture and combusted in the third combustion zone.

7. The radiant tube heating apparatus of claim 6, wherein the burner further comprises a secondary combustion device, the secondary combustion zone disposed within the secondary combustion device, the secondary combustion device comprising a barrel wall and an end plate disposed at one end of the barrel wall.

8. The radiant tube heating apparatus of claim 7, wherein a central portion of the end plate is provided with a first aperture in communication with the first combustion zone, the combustion products of the first combustion zone flowing through the first aperture to the second combustion zone; a plurality of second holes communicated with the mixing area are distributed around the first holes, and a part of air-flue gas mixture flows to a second combustion area through the second holes; another portion of the air-flue gas mixture then flows to the third combustion zone via the outside of the secondary combustion device.

9. Radiant tube heating device according to claim 1, characterized in that a flow control mechanism is provided in the flue gas recirculation line and/or the preheated air line.

10. Radiant tube heating device as claimed in claim 1, characterized in that the burner is constructed in an integrated manner.