A kind of air return device and double-chamber burner

Abstract

The present invention discloses a return gas device and a dual-chamber burner. The return gas device is composed of a shell provided with a first gas channel and a second gas channel and a built-in rotor. The gas is sucked in and discharged through the gap cavity between each surface of the rotor and the inner wall of the shell. The dual-chamber burner forms a multi-stage combustion effect through a secondary combustion chamber, shortens the residence time of the fuel in the high-temperature zone of the primary combustion chamber, reduces the thermal reaction NO, and has a significant inhibitory effect on "thermal reaction NO" and "fuel NO"; the gas entering the secondary combustion chamber forms a low-oxygen combustion effect; combined with the return gas device, part of the gas is sucked in and recycled, and then added to the combustion process, which again plays a dual effect of inhibiting nitrogen oxides and saving energy. The dual-chamber burner of the present invention combines staged combustion, reburning method, and low-oxygen combustion, has a significant effect of inhibiting nitrogen oxides, and has strong practicality and wide applicability.

Description

Technical Field

[0001] The invention relates to an air return device, in particular to an air return device and a double-chamber burner. Background Art

[0002] At present, the main technical means to control NOx emissions from gas burners include air staging, air swirl and direct current wind, gas staging, flue gas recirculation, etc. However, air staging and gas staging are limited by the installation size of existing burners, as well as the gas pressure and air pressure, and their contribution to reducing NOx emissions is limited.

[0003] Traditional flue gas recirculation is to open a hole behind the boiler induced draft fan, and set up a return fan to extract the flue gas generated by combustion and mix it with air before sending it into the burner. The structure is relatively complex and increases the risk probability. Therefore, a new return air device and burner are needed. Summary of the invention

[0004] In order to solve the deficiencies of the prior art, an object of the present invention is to provide a double-chamber low-nitrogen burner and a gas return device thereof.

[0005] In order to achieve the above object, the present invention adopts the following technical solution:

[0006] A return air device, comprising a cocoon-shaped housing and a triangular rotor arranged in the housing; the rotor is provided with a toothed inner ring, a toothed shaft with a diameter smaller than the inner diameter of the toothed inner ring is arranged in the toothed inner ring to link the rotor, so that the rotor rotates in the housing in a manner that the three vertices of the triangle are kept in contact with the inner wall of the housing;

[0007] On both sides of the gear shaft, the housing is provided with a first air passage and a second air passage respectively along the longitudinal direction;

[0008] The first air channel includes a first air inlet disposed at the bottom of the shell and a first air outlet disposed at the top of the shell.

[0009] The second air passage includes a second air outlet arranged at the bottom of the shell and a second air inlet arranged at the top of the shell.

[0010] A double-chamber burner comprises a primary combustion chamber and a secondary combustion chamber, wherein the secondary combustion chamber is arranged at the top of the primary combustion chamber and communicates with the primary combustion chamber through a pressure valve;

[0011] The first combustion chamber is provided with an ignition nozzle, and the chamber wall is provided with a fuel inlet and a combustion-supporting gas inlet; the second combustion chamber is provided with a gas outlet;

[0012] The gas outlet is provided with the return air device as claimed in claim 1, which is the first return air device; the gas outlet is connected to the first air inlet of the first return air device, and the second air outlet leads to the secondary combustion chamber.

[0013] The second gas outlet is connected to the secondary combustion chamber through the gas outlet, or connected to the secondary combustion chamber through the first gas return port of the secondary combustion chamber.

[0014] Furthermore, the first return air port is arranged at the cavity wall of the secondary combustion cavity, and is the second return air port; the second air outlet is connected to the first combustion cavity through the second return air port.

[0015] The first air outlet and the second air inlet are connected to the air outlet pipe in parallel.

[0016] A Tesla valve is arranged in the air outlet pipe, and an air stagnation cavity is arranged at the front end of the Tesla valve along the air flow direction; the air stagnation cavity is the hollow tube body of the air outlet pipe.

[0017] Furthermore, an air stagnation chamber is provided at the end of the Tesla valve.

[0018] Furthermore, the combustion-supporting gas inlet of the first combustion chamber is provided with the above-mentioned gas return device, which is the second gas return device; the combustion-supporting gas inlet is connected to the second gas outlet of the second gas return device, and the second gas inlet is connected to the combustion-supporting gas source through the combustion-supporting gas pipe;

[0019] The first air outlet of the second air return device is connected to the air stagnation cavity at the front end of the air outlet pipe through the air return pipe with a Tesla valve inside; the acceleration direction of the Tesla valve is from the air stagnation cavity end to the first air outlet end; the first air inlet is closed.

[0020] Furthermore, the above-mentioned return air pipe is wound around the outside of the combustion-supporting gas pipe.

[0021] The fuel in the above-mentioned fuel inlet includes coal powder, oil and combustible gas, and the combustible gas includes hydrogen, acetylene, ethylene, ammonia and hydrogen sulfide.

[0022] The combustion-supporting gas in the combustion-supporting gas inlet includes oxygen, ozone, chlorine and fluorine.

[0023] The present invention is beneficial in that:

[0024] The return gas device and the dual-chamber burner of the present invention utilize the three arc-shaped surfaces of the rotor so that each surface is like a piston. There is a gap cavity between each surface and the inner wall of the shell, which is used to inhale and discharge the gas, and to squeeze the gas to a certain extent in volume while being transported by the rotor to ensure the burnout effect. The dual channels of the shell are utilized in combination with the rotor, and the three independent gap cavities make the dual channels unobstructed in one direction in turn. The high pressure inside the burner and the low pressure difference outside are utilized to ensure the unidirectional main flow of the gas; the negative pressure of the independent gap cavity is utilized to ensure the recovery and reuse of a small amount of discharged gas. Then, by introducing it into different combustion chambers, the recovered gas can be subjected to different types of re-combustion in different combustion chambers to achieve the effect of low nitrogen and energy saving.

[0025] The return gas device and the dual-chamber burner of the present invention form a multi-stage combustion effect through the secondary combustion chamber, shorten the residence time of the fuel in the high-temperature zone of the primary combustion chamber, reduce the thermal reaction NO, and have a significant inhibitory effect on "thermal reaction NO" and "fuel NO"; the fuel gas entering the secondary combustion chamber forms a low-oxygen combustion effect; part of the fuel gas is sucked in and recycled, and then added to the combustion process, which again plays a dual effect of inhibiting nitrogen oxides and saving energy. The dual-chamber burner of the present invention combines staged combustion, re-combustion method, and low-oxygen combustion, has a significant effect of inhibiting nitrogen oxides, and has strong practicality and wide applicability. BRIEF DESCRIPTION OF THE DRAWINGS

[0026] Figure 1 It is a schematic structural diagram of the air return device of the present invention.

[0027] Figure 2 It is a structural schematic diagram of the double-chamber burner of the present invention.

[0028] Figure 3 It is a schematic structural diagram of the air outlet pipe of the present invention.

[0029] The meanings of the marks in the accompanying drawings are as follows: 1. Shell, 2. Rotor, 3. Gear shaft, 4. First air inlet, 5. First air outlet, 6. Second air outlet, 7. Second air inlet, 8. First air return device, 9. Second air return device, 10. Primary combustion chamber, 11. Secondary combustion chamber, 12. Fuel inlet, 13. Air outlet pipe, 14. Air return pipe, 15. Air stagnation chamber. DETAILED DESCRIPTION

[0030] The present invention is described in detail below with reference to the accompanying drawings and specific embodiments.

[0031] A double-chamber burner is composed of a primary combustion chamber 10, a secondary combustion chamber 11 and an air return device.

[0032] The secondary combustion chamber 11 is arranged at the top of the primary combustion chamber 10, a pressure valve is arranged between the primary combustion chamber 10 and the secondary combustion chamber 11, and the direction of the gas is from the primary combustion chamber 10 to the secondary combustion chamber 11; the cavity wall of the primary combustion chamber 10 is provided with a fuel inlet 12 and a combustion-supporting gas inlet, and the ignition nozzle is arranged in the primary combustion chamber and driven by the control device. The gas outlet is arranged at the cavity wall of the secondary combustion chamber 11, preferably at the cavity top.

[0033] The gas outlet is connected to the gas outlet pipe 13 through the first gas return device 8. The first gas return device 8 is composed of a cocoon-shaped shell 1 and a triangular rotor 2. The rotor 2 is provided with a gear inner ring, which is linked by a gear shaft 3 placed on the gear inner ring. The diameter (outer diameter) of the gear shaft 3 is smaller than the inner diameter of the gear inner ring. The gear shaft 3 is linked to the rotor 2 so that the rotor 2 rotates in the shell 1 in a manner that the three vertices of the triangle always keep in contact with the inner wall of the shell 1. In the longitudinal direction, the shell 1 is provided with a first air duct and a second air duct that respectively pass through the top and bottom of the shell 1, and the first air duct and the second air duct are respectively placed on both sides of the gear shaft 3; Figure 1 As shown, the first air passage includes a first air inlet 4 arranged at the bottom of the shell and a first air outlet 6 arranged at the top of the shell, and the second air passage includes a second air outlet arranged at the bottom of the shell and a second air inlet 7 arranged at the top of the shell.

[0034] The connection modes of the gas outlet and the first gas return device are:

[0035] Method 1: The gas outlet is enlarged to cover the first air inlet 4 and the second air outlet; for example, the gas outlet is circular (outer circle), the first air inlet 4 and the second air outlet are placed in the gas outlet at the same time, and an inner circle (contour) matching the gas outlet is set, and the contour is attached to the inner wall of the outer circle and sealed.

[0036] Method 2: The gas outlet is connected to the first air inlet 4, and a first air return port is provided on the cavity wall of the secondary combustion chamber, and the second air outlet is connected through the first air return port. Preferably, the first air return port is provided on the bottom side wall of the secondary combustion chamber.

[0037] Method three based on method two: the gas outlet and the first air inlet 4 are connected, the first return air port is arranged at the cavity wall of the first combustion cavity as the second return air port, and the second air outlet and the second return air port are connected to the first combustion cavity.

[0038] The structure of the air outlet pipe 13 is preferably: both ends are set as hollow air stagnation chambers 15, and the middle section is provided with a Tesla valve as a smooth air chamber. The air stagnation chamber 15 is a hollow tube body of the air outlet pipe. The connection method of the first air return device and the air outlet pipe is: the first air outlet 6 and the second air inlet 7 are connected in parallel to the air stagnation chamber 15 at one end of the air outlet pipe, and the Tesla valve is used to accelerate the gas along the flow direction of the airflow.

[0039] When using,

[0040] The fuel is added into the primary combustion chamber from the fuel inlet 12 and the supporting combustion gas is added into the supporting combustion gas inlet. The control device drives the ignition nozzle to ignite. The gas is released after combustion. The gas is pressurized in the primary combustion chamber. When the pressure is greater than the pressure valve, the pressure valve opens and the gas flows from the primary combustion chamber into the secondary combustion chamber.

[0041] The fuel gas accumulates, stays, and is pressurized in the secondary combustion chamber. If the fuel is solid or granular, the unburned fuel particles in the fuel gas can further burn in a smoldering manner under high temperature and pressure; if the fuel is gas, it can further react under high temperature and pressure to achieve the combustion effect.

[0042] The gear shaft 3 of the first air return device is linked by the shaft of the motor, and the triangular rotor 2 rotates in the housing. The three vertices of the triangle are attached to the inner wall of the housing, and a gap cavity is formed between the vertices, and the gap cavity rotates with the rotation of the rotor. Figure 1 As shown, taking the clockwise rotation of the rotor as an example, when the top of the rotor slides over the first air inlet, as the rotor continues to rotate, the cavity of the gap becomes larger and larger, forming a certain negative pressure, sucking the gas in the secondary combustion chamber, and when another adjacent top slides over the first air inlet, the gap cavity storing the gas is closed. The gas is transported along the gap cavity and undergoes a certain volume compression, further achieving a "combustion effect". When the current top slides over the first air outlet 6 at the top, the gap cavity is connected to the first air outlet 6, and the gas flows out from the first air outlet.

[0043] The outflowing gas enters the stagnant gas cavity of the gas outlet pipe, where it is retained. Part of the gas enters the gas flow cavity, flows along the Tesla valve, and flows out through the acceleration of the Tesla valve, and enters the stagnant gas cavity at the other end. Through the acceleration of the Tesla valve, the gas in the stagnant gas cavity flowing out from the other end achieves the effect of pressurized outflow. The other part of the gas is sucked in from the second air inlet 7 by the continuously rotating rotor, and then discharged from the second air outlet, entering the second combustion cavity (the gas returns from the first air inlet in method one, and the gas returns from the first return gas port in method two) or the first combustion cavity (the second return gas port in method three), that is, part of the gas is sucked back and enters the burner, mixed and then burned. Due to the gas recycling, the heat capacity of the gas is large, the combustion temperature is reduced, and NOx is reduced. Method three is to recirculate part of the gas directly in the burner (first combustion cavity) and add it to the combustion process, which has the dual effects of inhibiting nitrogen oxides and saving energy.

[0044] Based on the structure of method 1 and method 2:

[0045] The return air pipe 14 is connected to the side of the stagnant air cavity at the front end of the air outlet pipe. A Tesla valve is arranged in the return air pipe 14 to accelerate the air flow from the stagnant air cavity end to the other end of the return air pipe; the other end of the return air pipe is connected to the first air outlet 6 of the second return air device 9, the second air inlet of the second return air device 9 is connected to the supporting combustion gas source through the supporting combustion gas pipe, the supporting combustion gas inlet is connected to the second air outlet of the second return air device, and the first air inlet is closed. That is, after the rotation of the rotor in the second return air device, a small amount of gas in the stagnant air cavity sucked in by negative pressure is mixed with the supporting combustion gas in the gap cavity of the second device, and then enters the first combustion cavity. Preferably, the return air pipe is wound around the outside of the supporting combustion gas pipe to preheat the supporting combustion gas.

[0046] The above shows and describes the basic principles, main features and advantages of the present invention. Those skilled in the art should understand that the above embodiments do not limit the present invention in any form, and any technical solution obtained by equivalent replacement or equivalent transformation falls within the protection scope of the present invention.

Claims

1. A gas return device, characterized in that: It comprises a cocoon-shaped housing and a triangular rotor arranged in the housing; the rotor is provided with a toothed inner ring, a toothed shaft with a diameter smaller than the inner diameter of the toothed inner ring is arranged in the toothed inner ring to link the rotor, so that the rotor rotates in the housing in a manner that the three vertices of the triangle keep in contact with the inner wall of the housing; On both sides of the gear shaft, the housing is provided with a first air passage and a second air passage respectively along the longitudinal direction; The first air passage comprises a first air inlet arranged at the bottom of the shell and a first air outlet arranged at the top of the shell, and the second air passage comprises a second air outlet arranged at the bottom of the shell and a second air inlet arranged at the top of the shell.

2. A double-chamber burner, characterized in that: It includes a primary combustion chamber and a secondary combustion chamber, wherein the secondary combustion chamber is arranged at the top of the primary combustion chamber and communicates with the primary combustion chamber through a pressure valve; The first combustion chamber is provided with an ignition nozzle, and the chamber wall is provided with a fuel inlet and a combustion-supporting gas inlet; the second combustion chamber is provided with a gas outlet; The gas outlet is provided with the return air device as claimed in claim 1, which is the first return air device; the gas outlet is connected to the first air inlet of the first return air device, and the second air outlet leads to the secondary combustion chamber.

3. The burner according to claim 2, characterized in that: The second gas outlet leads into the secondary combustion chamber through the gas outlet, or leads into the secondary combustion chamber through the first return gas port of the secondary combustion chamber.

4. The burner according to claim 3, characterized in that The first return air port is arranged at the cavity wall of the secondary combustion cavity as the second return air port; the second gas outlet is connected to the first combustion cavity through the second return air port.

5. The burner according to claim 2, characterized in that: The first air outlet and the second air inlet are connected to the air outlet pipe in parallel. A Tesla valve is arranged in the air outlet pipe, and an air stagnation cavity is arranged at the front end of the Tesla valve along the air flow direction; the air stagnation cavity is the tube body of the air outlet pipe which is a hollow cavity.

6. The burner according to claim 5, characterized in that An air stagnation chamber is also provided at the end of the Tesla valve.

7. The burner according to claim 5, characterized in that The combustion-supporting gas inlet of the primary combustion chamber is provided with the return gas device as claimed in claim 1, which is a second return gas device; the combustion-supporting gas inlet is connected to the second gas outlet of the second return gas device, and the second gas inlet is connected to the combustion-supporting gas source through the combustion-supporting gas pipe; The first air outlet of the second air return device is connected to the air stagnation cavity at the front end of the air outlet pipe through the air return pipe with a Tesla valve inside; the acceleration direction of the Tesla valve is from the air stagnation cavity end to the first air outlet end; the first air inlet is closed.

8. The burner according to claim 7, characterized in that The return air pipe is wound around the outside of the combustion-supporting gas pipe.

9. The burner according to claim 2, characterized in that The fuel in the fuel inlet includes coal powder, oil and combustible gas, and the combustible gas includes hydrogen, acetylene, ethylene, ammonia and hydrogen sulfide.

10. The burner according to claim 2, characterized in that The combustion-supporting gas in the combustion-supporting gas inlet includes oxygen, ozone, chlorine and fluorine.

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