CN107062918B

CN107062918B - Smoke distribution device for heat accumulating type combustion industrial furnace, smoke distribution assembly with smoke distribution device and industrial furnace

Info

Publication number: CN107062918B
Application number: CN201710035350.5A
Authority: CN
Inventors: 顾向涛; 刘义; 宋长春; 高健; 宫立兵
Original assignee: Chongqing Wokesiboneng Technology Co ltd
Current assignee: CHONGQING WORKS TECHNOLOGY CO.,LTD.
Priority date: 2016-12-09
Filing date: 2017-01-17
Publication date: 2023-04-07
Anticipated expiration: 2037-01-17
Also published as: CN107062918A

Abstract

The invention provides a smoke distribution device, a smoke distribution assembly and an industrial furnace for reducing nitride emission of a heat accumulating type combustion industrial furnace, wherein the industrial furnace comprises a combustor, a fan for supplying combustion air and a smoke exhaust pipeline, the fan is provided with a fan inlet for being connected with the smoke distribution device, and the smoke distribution device comprises: a cylindrical body having a first end for connection with a flue gas return duct, a second end for connection to a fan inlet, and a sidewall extending between the first and second ends, the flue gas return duct directing flue gas in a flue gas discharge duct to flow back to the fan; a plurality of air inlets provided on the sidewall to introduce external air; and a regulating device for regulating the air inlet area of the plurality of air inlets to pre-configure the mixing ratio of the flue gas and the air; when the flue gas return pipe and the smoke distributing device are connected to the industrial furnace, the returned flue gas and the introduced air are mixed into the combustion air by using the negative pressure of the fan inlet before being introduced into the fan inlet. The invention greatly reduces the nitride in the discharged flue gas.

Description

Smoke distribution device for heat accumulating type combustion industrial furnace, smoke distribution assembly with smoke distribution device and industrial furnace

Technical Field

The invention relates to a smoke distribution device for a regenerative combustion industrial furnace, a smoke distribution assembly with the smoke distribution device and the industrial furnace.

Background

In order to save energy, especially for the control of multiple temperature zones, multiple burners are needed, and periodic industrial furnaces with greatly varying energy supplies, such as trolley heating furnaces, trolley heat treatment furnaces, chamber furnaces in the forging and casting industry, are needed. At present, the heat storage combustion technology is widely adopted to obtain the limit heat recovery, and the temperature of the flue gas discharged by the heat storage combustion is only about 100-150 ℃. For the periodic industrial furnace, the energy supply in the heating stage is generally 100% of set capacity, and after heat preservation, when the heat absorption of the workpiece and the heat absorption of the furnace body are close to the tail sound, the energy supply only needs to be a few percent of the set capacity, as long as the heat dissipation loss is met, therefore, the general continuous control is usually in an overshoot state, the regulation effect is poor, and therefore, the periodic industrial furnace is usually controlled in a pulse combustion mode. The pulse control converts the energy supply mode into 0 and 1 modes, 1 is full power, 0 is zero power or low power, and the power output ratio is determined by the supply time lengths of 0 and 1, so that the power supply can be adjusted greatly. The control features that 0-100% power supply is controllable and stepped, and the switch speed is fast, usually lower than 1 second. Therefore, the control mode for the pulse control using the continuous control valve is usually failed because the actuator in the continuous control has a far lower operation speed than the opening and closing speed of the pulse control shutter. Especially for the situation of multi-temperature zone and multi-burner control, the flow in the gas, air, flue gas and other pipelines presents unpredictable jumping change, and the flow regulation mode adopted in the prior art can not realize regulation.

The heat accumulating type combustion industrial furnace adopts paired burners with heat accumulators to carry out controlled combustion. When one burner is burning, the other burner sucks air and discharges smoke, high-temperature smoke and the heat accumulator exchange heat energy when passing through the heat accumulator, the heat accumulator absorbs heat, and the temperature of the high-temperature smoke is reduced; after a period of time, the heat storage body is saturated, the direction is changed, and when another burner burns, cold air or fuel enters the burner from the heat storage body with higher heat absorption temperature and is heated by the heat storage body. Simultaneously, the nozzle of former burning is breathed in and is discharged fume, and high temperature flue gas heats its heat accumulator again, carries out the heat exchange, through two continuous burning in turn repeatedly of nozzle, reaches energy-conserving effect.

However, the conventional regenerative combustion has a very high flame temperature, and generates a large amount of reactive nitrides, which are used as combustion exhaust gas, and thus, ozone layer may be damaged, acid rain may be caused, and strong stimulation may be generated to human body, and lung diseases may be caused. The emission of nitrides causes great environmental pollution and needs to be strictly controlled.

A conventional approach to reduce nitride has been to use low nitride burners. For a common combustion system, the temperature of the exhausted flue gas is very high, and the flue gas is directly fed into a fan to possibly damage the fan, so the existing research direction focuses on developing the structure of a burner to reduce the content of nitride, and the cost of the burner is high. For a system adopting heat accumulating type combustion, the exhaust gas temperature is about 150 ℃, which is the temperature that a fan can bear, and if the exhaust gas is refluxed, the flame temperature can be greatly reduced by a method of reducing the oxygen content in combustion-supporting air, so that the nitride content in combustion products can be greatly reduced.

Disclosure of Invention

In order to overcome the defects in the prior art, the invention provides a smoke distribution device for a heat accumulating type combustion industrial furnace, which is used for reducing the emission of nitrides by supplying combustion air with a preset mixing ratio in cooperation with a smoke return pipeline.

According to an aspect of the present invention, there is provided a smoke distribution device for a regenerative combustion industrial furnace, the industrial furnace comprising a burner, a fan for supplying combustion air to the burner and a flue gas duct for exhausting flue gas generated by the burner, the fan having a fan inlet for connection to the smoke distribution device, the smoke distribution device comprising: a cylindrical body having a first end for connection with a flue gas return duct, a second end for connection to a fan inlet, and a sidewall extending between the first and second ends, the flue gas return duct directing flue gas in a flue gas duct to flow back to a fan; a plurality of air inlets provided on the sidewall to introduce external air; and adjusting means for adjusting the air intake area of the plurality of air inlets to pre-configure the mixing ratio of the flue gas and the air; wherein, under the condition that the flue gas backflow pipeline and the smoke distribution device are connected to the industrial furnace, the flue gas which flows back through the flue gas backflow pipeline and the air which is introduced into the smoke distribution device are mixed into the combustion-supporting air by using the negative pressure of the fan inlet before being introduced into the fan inlet.

According to the smoke distribution device, the mixing proportion of the backflow smoke and the introduced air is preset, so that the distributed air and smoke are mixed, and the mixture of the air and the smoke enters the combustor through the pipeline by the fan, so that the content of nitrides in the discharged smoke can be greatly reduced. The invention is especially suitable for the process of pulse combustion control of a plurality of burners and a plurality of temperature zones, and when the plurality of burners and the plurality of temperature zones are controlled, stable smoke distribution proportion can be obtained no matter how the burner shutter acts, thereby realizing that the discharge amount of nitrides can be reduced at each stage of the work of the industrial furnace.

The adjusting means pre-configures a mixing ratio of the flue gas and the air based on a normal operation furnace temperature of the industrial furnace before the industrial furnace normally operates, and substantially maintains the mixing ratio during the normal operation of the industrial furnace. Therefore, the smoke distribution device does not need to participate in the process control of the industrial furnace, and the operation management of the industrial furnace is greatly simplified.

According to a variant, the cylindrical body is configured to be connected in series in fluid communication with the flue gas return duct to form a mixing zone of flue gas and air inside the cylindrical body.

According to another variant, the cylindrical body is configured so that the flue gas return duct extends from the first end of the cylindrical body through the interior of the cylindrical body and to the second end of the cylindrical body, so as to form a mixing zone of flue gas and air on the end face of this second end.

Preferably, the cylindrical body is configured such that the flue gas return duct is centrally mounted to the first end of the cylindrical body.

Preferably, the air inlet is formed as a slit linearly extending in a longitudinal direction of the cylindrical body.

Preferably, the plurality of air inlets are uniformly arranged along a circumferential direction of the cylindrical body.

According to an aspect of the invention, the adjustment means comprises an annular adjustment body surrounding at least a portion of the cylindrical body, the adjustment body being movable relative to the cylindrical body.

Preferably, the adjusting body is rotatable with respect to the cylindrical body, and a plurality of air inlet adjusting holes adapted to the air inlet to adjust an amount of air inlet are provided on a circumferential surface of the adjusting body.

According to another aspect of the invention, the open area of the second end is greater than the open area of the fan inlet.

According to yet another aspect of the invention, the second end of the cylindrical body has a transition section connected to the blower inlet, the transition section having a tapered portion.

According to yet another aspect of the invention, the second end of the cylindrical body further has a connection tube connected to the blower inlet, the transition section extending into the connection tube, one end of the connection tube being connected to the end of the transition section opposite the blower inlet, the other end of the connection tube being connected to the blower inlet.

According to a further aspect of the invention, the industrial furnace employs pulsed combustion control, and/or the fan is a centrifugal fan.

The invention also relates to a smoke distribution assembly which comprises the smoke distribution device and a smoke return pipeline connected with the smoke distribution device.

The invention also relates to an industrial furnace, which comprises the smoke distribution assembly.

Drawings

Fig. 1 is a partial structural view of a smoke distributing apparatus according to the present invention in a state of being installed to a regenerative combustion industrial furnace.

Fig. 2 is a schematic structural view of a smoke distribution device according to a first embodiment of the present invention.

Figure 3 is an enlarged partial view of the adjustment means of the smoke dispensing apparatus of figure 2 in an adjusted condition.

Fig. 4 (a) and 4 (b) are a front view and a side view, respectively, of an adjustment body of the adjustment device.

Figure 5 is a schematic structural view of a smoke dispensing device according to a second embodiment of the invention.

Figure 6 is an enlarged partial view of the regulating device of the cigarette dispensing device according to the invention in the fastened state.

Fig. 7 (a) and 7 (b) are schematic structural views of a smoke dispensing device according to a third embodiment of the present invention.

Fig. 8 (a) and 8 (b) are schematic structural views of a smoke dispensing device according to a fourth embodiment of the present invention.

Figure 9 is a schematic structural diagram of a smoke distribution device according to a fifth embodiment of the invention.

Figure 10 (a) is a schematic view of a smoke dispensing device according to the present invention provided with an alternative adjustment means.

Figure 10 (b) is a cross-sectional view of the smoke dispensing device shown in figure 10 (a).

Fig. 10 (c) is a plan development view of the adjusting device shown in fig. 10 (a).

Detailed Description

Fig. 1 shows a schematic view of a smoke distribution device 1 according to the present invention in a state of being mounted to a regenerative combustion industrial furnace.

As shown in fig. 1, the regenerative combustion industrial furnace includes a burner (not shown), a blower 101 for supplying combustion air to the burner, and a flue gas discharge duct 102 for discharging combustion flue gas of the burner.

The flue gas return duct 2 is connected to the smoke exhaust duct 102 for guiding the flue gas in the smoke exhaust duct 102 back to be introduced into the fan inlet 103. As shown in fig. 2, the flue gas return duct 2 comprises an inlet end 21 for connection to a smoke exhaust duct 102 of the industrial furnace and an outlet end 22 for supplying the returned flue gas to a fan inlet 103 of the industrial furnace. For advantageous control of the operation, a switching valve 23 is provided on the flue gas return pipe 2 to control whether the flue gas is returned or not, as shown in fig. 1. Usually, the opening and closing valve 23 is opened after the furnace reaches a certain temperature (usually, the opening and closing valve is opened when the furnace temperature reaches a certain temperature (usually 600-700 ℃), although the opening temperature can be set according to the nitride discharge amount). In addition, in order to regulate the amount of flue gas that flows back, a flow regulating valve 24 is also provided on the flue gas return duct 2, which flow regulating valve 24 is preferably in a manual form, and once set according to requirements, no regulation is necessary, thus greatly simplifying the operation.

The smoke distribution device 1 is installed to a blower inlet 103 of a regenerative combustion industrial furnace to introduce combustion air. In particular, the smoke dispensing device 1 is able to introduce fresh air from the outside and mix it with the flue gases returning from the smoke exhaust duct 102. The smoke distributing device 1 mainly configures introduced fresh air and flue gas into combustion air according to different working conditions of the industrial furnace according to a preset proportion according to the temperature of the industrial furnace, and supplies the configured combustion air into the fan 101 by using the negative pressure of the fan inlet 103. It should be noted that the smoke distribution device 1 is configured with a mixing ratio of smoke and air in advance for different industrial furnaces, for example, the mixing ratio is set in advance mainly based on the furnace temperature when the industrial furnace is in normal operation, and only needs to be adjusted finely according to actual working conditions when in field debugging. The smoke distribution device 1 keeps the mixing ratio substantially unchanged after normal operation of the industrial furnace. As the flue gas with low oxygen content is added into the combustion-supporting air, the total oxygen content of the combustion-supporting air is reduced, thereby reducing the combustion temperature of combustion flame and achieving the purpose of reducing the emission of nitride in combustion products. And because the smoke distribution device only configures the mixing proportion in advance and does not participate in process control, the operation of the industrial furnace is simple and reliable.

(first embodiment)

Fig. 2 to 4 show a schematic structure of a smoke distribution device 3 according to a first embodiment of the present invention.

As shown in fig. 2, the smoke dispensing device 3 includes a cylindrical body 31, a plurality of air inlets 32 provided on the cylindrical body 31, and an adjusting device 33 for adjusting an air intake area of the air inlets 32.

The cylindrical body 31 comprises a first end 311 for connection with the flue gas return duct 2, a second end 312 for connection to the blower inlet 103 and a side wall 313 extending between the first end 311 and the second end 312.

The first end 311 is provided with an opening for connection to the outlet end 22 of the flue gas return duct 2 for introducing flue gases discharged from the outlet end 22 into the cylindrical body 31. The outlet end 22 is preferably disposed at a center position of the first end 311, that is, the opening is disposed at a center position of the first end 311. The returned flue gas enters the cylindrical body 31 in the direction indicated by the arrow a in the figure, and is fully mixed with the fresh air therein.

The side wall 313 is opened with a plurality of openings to form the air inlet 32. The opening is preferably an elongated slit extending in the longitudinal direction of the cylindrical body 31, such as a rectangular slit, so that the air intake area of the air inlet 32 can be linearly adjusted. However, it is contemplated that the opening may be other shapes such as circular, oval, polygonal, etc. The plurality of air inlets 32 are also preferably evenly distributed along the circumference of the cylindrical body 31, so as to enhance the stability of the smoke dispensing apparatus 3 in the operating state. Also, the air inlet 32 is not limited to being formed on the sidewall 313, but may be formed on the first end 311 and/or the second end 312 to increase the amount of air introduced. In this embodiment, the air inlet 32 is preferably disposed away from the first end 311 and closer to the second end 312, whereby in the operating state, incoming fresh air enters the cylindrical body 31 in the direction indicated by the arrow B in the figure, and collides with the incoming back-streaming flue gas to generate turbulence, thereby being thoroughly mixed.

The second end 312 may be connected directly or indirectly to the blower inlet and is provided with an opening to introduce combustion air into the blower inlet 103. To ensure that a stable static pressure zone is formed within the cylindrical body 31, the open area of the second end 312 is preferably greater than the open area of the fan inlet 103.

The cylindrical body 31 is preferably cylindrical, however, it may also take a cylindrical structure such as an L-shape or an arc-shaped elbow, as long as the cylindrical body 31 can introduce combustion air into the blower inlet 103. In addition, the cylindrical body 31 is preferably a one-piece cylinder. However, the cylindrical body 31 may also be formed by assembling a plurality of portions separated from each other. For example, the cylindrical body 31 may be surrounded at intervals by a plurality of pillars each having one end fixed to a plate-like member, and a plurality of slits constituting the plurality of air inlets 32 are formed between the pillars. These struts preferably extend in the axial direction in parallel with each other, so that the plurality of air inlets 32 are formed to extend linearly in the axial direction of the cylindrical body 31.

Fig. 3 is a partially enlarged view of the adjusting device 33. The adjustment device 33 comprises an adjustment body 331 surrounding the cylindrical body 31 of the smoke dispensing device 3 and covering a part of the longitudinal length of the cylindrical body 31, and a position adjuster 332 for adjusting the position of the adjustment body 331 relative to the cylindrical body 31.

The regulating body 331 is a cylindrical piece that fits against the cylindrical body 31 of the smoke dispensing apparatus 3, preferably with a close fit for precise control of the amount of intake air. As shown in fig. 4 (a), 4 (b), the adjustment body 331 is provided with a plurality of mounting lugs 3311 (three are shown) equally spaced along its circumference, each mounting lug 3311 having a central hole for mounting to a corresponding position adjuster 332. It is contemplated that the number of mounting lugs 3311 is not limited to three, so long as the adjustment device 33 is circumferentially fixed.

The position adjuster 332 includes a screw 3321 having a head and two fastening nuts 3322 fitted around the screw 3321. The screw 3321 passes through the bracket 314 at one end of the cylindrical body 31 and through the corresponding mounting lug 3311 of the adjusting body 331, and two fastening nuts 3322 are provided at both sides of the mounting lug 3311 for being tightened from both sides. The adjustment body 331 is slidable with respect to the position adjuster 332 via the mounting lugs 3311. After the adjusting body 331 is moved to a set position based on the monitoring result of the nitride content in the exhaust fume, the fastening nuts 3322 at both sides of the mounting lug 3311 are tightened to fix the position of the adjusting body 331, as shown in fig. 6, so that the air intake area of the air inlet 32 is kept constant, for the purpose of configuring the returned fume and the fresh air.

It has been described above that the adjustment body 331 of the adjustment device 33 slides on the cylindrical body 31 to adjust the amount of intake air, however, the adjustment device 33 may also adopt a rotary type adjustment, that is, the adjustment body 331 may be rotated on the cylindrical body 31 to move relative thereto, at which time the adjustment body 331 and the cylindrical body 31 may be threadedly engaged. In other words, it is sufficient if the adjustment device 33 is movable relative to the cylindrical body 31 to adjust the air intake area of the air inlet thereon.

Although the adjustment device 33 is described above as being manually adjustable, it may be electrically or pneumatically adjustable.

The discharge of the regenerative combustion nitrides is only related to the mixing ratio of the flue gas and the temperature of the furnace. A large number of experiments prove that the obtained nitride emission value is basically in a stable value range when the proportion of flue gas and air is preset corresponding to a certain heat accumulating type combustor and a certain furnace temperature, and the characteristics of the nitride emission value are repeatable. Therefore, as mentioned above, before the industrial furnace is normally operated, the premixed ratio of the flue gas and the air can be set according to the thermal process and the use temperature of the industrial furnace from the design point of the industrial furnace. During actual debugging, firstly, the adjusting device is used for presetting the mixing ratio of the flue gas and the air based on the furnace temperature of the industrial furnace during normal operation (only fine adjustment is needed according to the actual working condition), and the ratio is basically maintained during the normal operation of the industrial furnace, namely the adjusting device does not participate in process control. The preset flue gas and air ratio has great significance for reducing the nitride emission of the whole pulse control combustion system, and a simple and feasible solution can be obtained.

After the mixing ratio of the flue gas and the air is adjusted, the flue gas flowing back from the smoke exhaust duct 102 of the industrial furnace flows into the cylindrical body 31 of the smoke distribution device 3 from the outlet end 22 of the flue gas return duct 2, is mixed with the fresh air introduced into the cylindrical body 31 through the plurality of air inlets 32, and flows into the fan inlet 103 under the action of the negative pressure generated in the cylindrical body 31 by the operation of the fan 101, so that the oxygen content in the combustion air is reduced ³ This is far beyond the state-specified emission standards.

In addition, the smoke distribution device can adjust the air inflow without arranging an additional flow adjusting valve, and the air inflow area of the air inlet can be linearly adjusted, so that the air inflow is conveniently and accurately controlled.

(second embodiment)

Fig. 5 shows a schematic structure of a smoke dispensing device 1 according to a second embodiment of the present invention. This second embodiment differs from the first embodiment only in that the outlet end 22 of the flue gas return duct 2 extends from the first end 311 of the cylindrical body 31 of the smoke dispensing apparatus 3 through the interior of the cylindrical body 31 and to the second end 312 of the cylindrical body 31 to form a mixing zone of flue gas and air at the end face of this second end 312, i.e. the plane in which this end lies. The other parts of this embodiment may be the same as the first embodiment. For the sake of brevity, only this difference is described herein.

In this embodiment, the outlet end 22 of the smoke return duct 2 passes through the cylindrical body 31 of the smoke dispensing device 3, so that an annular space 34 is formed in the cylindrical body 31 of the smoke dispensing device 3 to receive the fresh air introduced from the air inlet 32, and the returned smoke and the introduced fresh air are sucked into the fan inlet 103 by using the negative pressure at the end surface of the smoke dispensing device 1 close to the fan inlet (i.e., at the second end 312 of the cylindrical body 31 and the outlet end 22 of the smoke return duct 2), so that the area distribution is performed by designing an area distribution surface, thereby achieving the effect similar to that of the first embodiment described above.

In this embodiment, to better introduce fresh air, the plurality of air inlets 32 are preferably disposed away from the second end 312 of the cylindrical body 31 and closer to the first end 311, thereby avoiding the formation of dead zones within the cylindrical body 31.

(third embodiment)

Fig. 7 (a) and 7 (b) are schematic structural views showing a smoke dispensing device according to a third embodiment of the present invention. This embodiment differs from the first embodiment in that the second end 312 of the smoke dispensing apparatus 3 is provided with a transition 3120 to which the blower inlet is connected to accommodate different spatial arrangements of various industrial furnaces. The transition section 3120 may have a taper, such as a cone, to connect directly or indirectly with the fan inlet. The transition 3120 may also have a straight barrel portion connected to the tapered portion, which may be connected directly or indirectly to the blower inlet. However, the transition 3120 may take other cylindrical shapes as long as it is suitably connected to the blower inlet to supply combustion air.

Fig. 7 (a) shows the air inlet 32 disposed proximate the second end 312 of the smoke dispensing device 3, while fig. 7 (b) shows the air inlet 32 disposed proximate the first end 311 of the smoke dispensing device 3, thereby achieving a different air flow direction.

(fourth embodiment)

Fig. 8 (a) and 8 (b) are schematic structural views showing a smoke dispensing device according to a fourth embodiment of the present invention. This embodiment differs from the second embodiment in that the second end 312 of the smoke dispensing device 3 is provided with a transition 3120 to which the inlet of the fan is connected to accommodate different arrangements of various industrial furnaces. The transition section 3120 may have a taper, such as a cone, to connect directly or indirectly with the blower inlet. The transition section 3120 may also have a straight barrel portion connected to the tapered portion, which may be directly or indirectly connected to the blower inlet. However, the transition 3120 may take other cylindrical shapes as long as it is appropriately connected to the blower inlet to supply combustion air.

In correspondence with the smoke dispensing device 3, the outlet end 22 of the smoke return duct 2 passes from the first end 311 of the smoke dispensing device 3 through a transition 3120 to the second end 312, so that air is mixed with the smoke on a distribution surface (end surface) at the second end 312.

Fig. 8 (a) shows the air inlet 32 disposed proximate the second end 312 of the smoke dispensing device 3, while fig. 8 (b) shows the air inlet 32 disposed proximate the first end 311 of the smoke dispensing device 3, thereby achieving a different air flow direction.

(fifth embodiment)

Figure 9 shows a schematic structural view of a smoke dispensing device according to a fifth embodiment of the present invention. This embodiment differs from the fourth embodiment in that the second end 312 of the smoke dispensing device 3 is further provided with a connecting tube 3121 connected directly or indirectly to the blower inlet, the transition 3120 extending into this connecting tube 3121.

The connection pipe 3121 is formed in an L-shape having one end connected to an end of the transition section 3120 opposite to the blower inlet and the other end connected to the blower inlet, thereby enhancing flexibility in connection with the blower inlet. The connection tube 3121 may employ a flexible hose.

The adjustment device 33 of the smoke dispensing device 3 described above in the first embodiment is rotatable to adjust the amount of intake air. A specific example of this adjustment is given below.

Fig. 10 (a) shows a schematic configuration diagram in which the adjustment body 331 of the adjustment device 33 is rotated relative to the cylindrical body 31 of the smoke dispensing device 3 to adjust the amount of intake air. Fig. 10 (b) and 10 (c) are a sectional view and a plan development thereof, respectively.

The adjusting device 33 includes only an adjusting body 331 rotatably fitted with the cylindrical body 31 and a plurality of intake adjusting holes 3310 integrally formed on the adjusting body 331. The regulating body 331 is formed in a cylindrical shape such as a cylindrical shape surrounding the cylindrical body 31, and is provided on a circumferential surface thereof with air-intake regulating holes 3310, and these air-intake regulating holes 3310 may be square, rectangular, circular holes, or any other shape, preferably linear holes such as square or rectangular holes, so that the amount of intake air of the smoke distribution device 3 is regulated by the air-intake regulating holes 3310 in cooperation with the air inlet 32 on the cylindrical body 31. These intake adjustment holes 3310 are preferably evenly distributed along the circumferential direction of the adjustment body 331.

The double-headed arrow in fig. 10 (b) shows the rotation direction of the adjusting device 33 with respect to the cylindrical body 31, and the adjusting body 331 can be rotated clockwise or counterclockwise to adjust the overlapping area of the air intake adjusting holes 3310 and the air inlet 32 on the cylindrical body 31, that is, the air intake area, so as to be appropriately set according to the content of the nitrides in the exhaust fumes.

The above described adjustment device is simpler to operate and simplified in structure, applicable to all the previous embodiments of the invention.

The invention also relates to a smoke distribution assembly comprising a smoke distribution device according to the above embodiment and a smoke return duct connected to the smoke distribution device.

The invention also relates to an industrial furnace provided with the smoke distribution assembly.

The fan of the industrial furnace is preferably a centrifugal fan, and the pressure at the outlet of the centrifugal fan does not change greatly. When a certain burner or some burners do not work, the fan can automatically adjust the introduction amount of combustion-supporting air according to the requirements of the burners, so that once the configured proportion is set for a certain industrial furnace, the industrial furnace completely automatically operates, the manual participation required by the traditional equipment is greatly reduced, the operation error is reduced, and the labor cost is reduced.

In the industrial furnace provided with the smoke distribution assembly, 10-70% of the discharged smoke can be refluxed by presetting the air inlet area ratio of the smoke reflux pipeline and the smoke distribution device, so that the content of nitride in the discharged smoke of the industrial furnace is reduced.

Claims

1. A smoke distribution device for a regenerative-combustion industrial furnace, said industrial furnace including a burner, a fan for supplying combustion air to the burner and a flue gas duct for exhausting flue gas generated by the burner, said fan having a fan inlet for connection to said smoke distribution device, said smoke distribution device comprising:

a cylindrical body having a first end for connection with a flue gas return duct, a second end for connection to a fan inlet, and a sidewall extending between the first and second ends, the flue gas return duct directing flue gas in a flue gas duct to flow back to a fan;

a plurality of air inlets provided on the sidewall to introduce external air, the plurality of air inlets being located at the same axial position of the cylindrical body; and

adjusting means for adjusting the air intake area of the plurality of air inlets to pre-configure the mixing ratio of flue gas and air, the adjusting means comprising an annular adjusting body surrounding at least a portion of the cylindrical body, the adjusting body being formed as a single piece and being movable relative to the cylindrical body to adjust the air intake area of the plurality of air inlets;

wherein, under the condition that the flue gas return pipeline and the smoke distribution device are connected to the industrial furnace, the flue gas which flows back through the flue gas return pipeline and the air which is introduced into the smoke distribution device are mixed into the combustion-supporting air by utilizing the negative pressure of the inlet of the fan before being introduced into the inlet of the fan,

wherein the adjusting device is configured to pre-configure the mixing ratio of the flue gas and the air based on the normal operation furnace temperature of the industrial furnace before the industrial furnace normally operates, and the adjusting device substantially maintains the mixing ratio during the normal operation of the industrial furnace.

2. The smoke dispensing apparatus of claim 1, wherein the cylindrical body is configured to be connected in series in fluid communication with the smoke return conduit to form a mixing zone of smoke and air inside the cylindrical body.

3. The smoke dispensing apparatus of claim 1, wherein the cylindrical body is configured such that the smoke return conduit extends from a first end of the cylindrical body through an interior of the cylindrical body and to a second end of the cylindrical body to form a mixing zone of smoke and air on an end face of the second end.

4. A smoke distribution apparatus according to any one of claims 1-3, wherein said cylindrical body is configured such that said smoke return conduit is centrally mounted to a first end of said cylindrical body.

5. A smoking device according to any one of claims 1-3, wherein the air inlet is formed as a slit extending linearly in the longitudinal direction of the cylindrical body.

6. A smoking device according to any one of claims 1-3, wherein the plurality of air inlets are evenly arranged along the circumference of the cylindrical body.

7. A smoke distribution device according to any one of claims 1-3, wherein said adjusting body is rotatable relative to said cylindrical body, said adjusting body being provided with a plurality of air inlet adjusting holes on a circumferential surface thereof for adapting to said air inlet for adjusting the amount of air inlet.

8. A smoke distribution device according to any one of claims 1-3, wherein the open area of the second end of the cylindrical body is larger than the open area of the blower inlet.

9. A smoke distribution device according to any one of claims 1-3, wherein said industrial furnace employs pulsed combustion control and/or said fan is a centrifugal fan.

10. A smoke dispensing apparatus according to any one of claims 1-3, wherein the second end of the cylindrical body has a transition section connected to the blower inlet, the transition section having a tapered portion.

11. The smoke dispensing device of claim 10, wherein the second end of the cylindrical body further has a connecting tube connected to the blower inlet, the transition section extending into the connecting tube, one end of the connecting tube being connected to the end of the transition section opposite the blower inlet, the other end of the connecting tube being connected to the blower inlet.

12. A smoke distribution assembly for reducing nitride emissions from regenerative combustion industrial furnaces comprising a smoke distribution device according to any of claims 1-11 and a flue gas return duct connected to the smoke distribution device.

13. An industrial furnace comprising the smoke dispensing assembly of claim 12.