Safe and stable premixing gas burner with wide concentration range

Abstract

The invention belongs to the field of combustors, and particularly discloses a wide-concentration-range premixed gas safe and stable combustor which comprises an anti-backfire chamber, an anti-backfire device, a backfire signal detector, a gas concentration detector, a Venturi tube, a combustion chamber and a gradually-shrunk smoke collecting device. The anti-backfire chamber is used for feeding premixed gas into the combustion chamber and preventing the backfire phenomenon, the venturi tube and the stainless steel wire corrugated filler ensure that the gas is fully premixed, the control system adjusts the gas concentration and the fuel and air flow so that the gas concentration in a gas mixing cavity can be kept within the range of 6%-9%, the combustion chamber ignites the premixed gas, and the combustion chamber ignites the premixed gas. And the tapered flue gas collecting device is used for re-collecting flue gas and preheating premixed gas, so that a tempering phenomenon is prevented, and the combustion safety and stability are improved.

Description

Technical Field

[0001] The invention relates to the field of burners, and more particularly to a safe and stable burner for premixed gas in a wide concentration range. Background Art

[0002] The world's reserves are 2.6×10 14 m 3 Coal mine gas is one of the important unconventional natural gases. However, low-concentration coal mine gas has not been effectively utilized and is directly discharged into the atmosphere, generating up to about 28 billion m3 per year. 3 The CH4 emissions cause serious greenhouse effect and energy loss. Therefore, the utilization of low-concentration coal mine gas is of great significance for protecting clean fuel resources, environment and coal mine safety.

[0003] At present, in order to effectively utilize low-concentration gas, there are already some combustion devices that treat low-concentration coal mine gas generated during coal mining by combustion. However, these burners only have gas combustion functions or have made some achievements in anti-backfire, and do not consider how to quickly and conveniently introduce the required concentration of mixed gas at the front end of the burner, and do not effectively utilize the flue gas generated after combustion in the combustion chamber.

[0004] According to a low-concentration gas combustion device with patent number CN115076689A, the device includes an air intake assembly, a gas mixing assembly and a combustion chamber. The low-concentration gas enters the gas mixing assembly through the air intake assembly and is mixed in the gas mixing assembly. The mixed gas is transported to the combustion chamber through a delivery hose for combustion, thereby achieving the rational use of the low-concentration gas. However, the device does not fully consider the flashback phenomenon that may occur in the combustion chamber, which may affect the safety and efficiency of the device.

[0005] On the other hand, according to a premixed anti-flashback flameless burner with patent number CN110345475B, the device has carried out detailed research and design on the structure of its key components such as the anti-flashback unit and the injection unit and their specific settings. This design effectively solves the problem of high flashback risk during the combustion stage, and also has the advantage of fast switching of combustion modes, so it is particularly suitable for premixed combustion applications. However, the device does not have a device for conveniently and quickly adjusting the intake concentration in the premixing unit it designed, which may cause inconvenience when premixed gases of different concentrations need to be introduced. It is known that the concentration range of low-concentration gas is between 3% and 9%. Different phenomena will occur when mixed gases of different concentrations are introduced into the combustion chamber for combustion. Conveniently and quickly adjusting the intake concentration is more conducive to the smooth progress of the experiment. In addition, the patent does not design a device to make reasonable use of the exhaust gas generated after combustion. Summary of the invention

[0006] In view of the shortcomings of the prior art and the areas that can be improved, the patent of the present invention provides a safe and stable premixed gas burner with a wide concentration range. It has the advantages of being able to quickly adjust the intake concentration and fully premix the gas. A gas recovery pipeline is installed to recover the heat of the combustion exhaust gas, which serves as a preheating effect for the premixed gas in the anti-flashback chamber. It solves the problem that the burner cannot quickly adjust the concentration and reasonably utilize the exhaust gas generated by combustion, as mentioned in the background technology. At the same time, an anti-flashback device and a flashback signal detector are installed to further prevent the occurrence of flashback. To achieve the above purpose, the patent of the present invention provides the following technical solutions:

[0007] A safe and stable burner for premixed gas with a wide concentration range for low-concentration gas, which is equipped with a high-concentration methane storage tank and a blower, a fuel flow electronic control valve and an air flow electronic control valve, a fuel flow meter and an air flow meter, a gas intake valve, a fully premixing chamber, an anti-backfire chamber, a combustion chamber, a tapered flue gas collection device, a flue gas guide pipe, a ring pipe and a chimney in sequence along the gas flow direction.

[0008] The device includes a high-concentration methane storage tank, a blower, a fuel flow electronic control valve, an air flow electronic control valve, a fuel flow meter and an air flow meter. These components are used to quickly adjust the intake concentration and control the gas concentration entering the combustion chamber between 6% and 9%. The output end of the electronic valve is connected to the control system via a wireless connection.

[0009] The fully premixing chamber is used to obtain premixed gas and send it to the anti-flashback chamber. The fully premixing chamber includes: a fuel air pipe connected to a high-concentration methane storage tank, an air duct connected to a blower, a gas inlet valve, a gas mixing chamber equipped with several layers of horizontally and vertically placed stainless steel wire corrugated fillers with different pore sizes, and a gas concentration detector. The output end of the gas concentration detector is wirelessly connected to the control system and works in coordination with the fuel flow electronic control valve and the air flow electronic control valve.

[0010] The anti-backfire chamber is used to deliver the premixed gas into the combustion chamber and prevent the occurrence of backfire. It includes an anti-backfire channel, an anti-backfire device, a backfire signal detector, a gas concentration detector and a venturi tube formed by an expansion and contraction grid plate. The anti-backfire device can rapidly reduce the flame temperature when the flame reaches here due to the characteristics of the material, and the shape of the flame is broken up, the combustion speed is rapidly reduced, and the air flow speed is greater than the combustion speed, making it difficult to continue burning back. The backfire signal detector is used to detect backfire. The output end of the backfire flame detector is wirelessly connected to the control system. When a flame signal is detected, the control system immediately cuts off the fuel flow electronic control valve; the gas concentration detector is used to perform secondary concentration detection on the premixed gas mixture, and its output end is wirelessly connected to the control system; the anti-backfire channel is provided with an expansion and contraction grid plate, and the expansion and contraction grid plate forms a preset number of venturi tube channels in the anti-backfire channel to enhance the anti-backfire effect.

[0011] The combustion chamber is used for igniting the premixed gas so that the premixed gas burns therein.

[0012] The gradually contracting flue gas collecting device is used to collect the flue gas emitted after combustion and discharge it to the annular pipe on the outer layer of the anti-flashback chamber through the flue gas duct, preheat the premixed gas in the anti-flashback chamber in advance, and finally discharge it through the chimney.

[0013] As a further preferred embodiment, the front end of the fully premixing chamber is provided with a high-concentration methane storage tank, a blower, an electronic valve for controlling the intake flow of the high-concentration methane storage tank and the blower, and a gas flow meter for high-concentration methane and air. When the gas concentration detector in the premixing chamber detects that the gas concentration in the gas mixing chamber is not in the range of 6%-9%, an electrical signal is sent to the control system. Through the control system, the gas concentration detector cooperates with the fuel flow electronic control valve and the air flow electronic control valve to adjust the flow of high-concentration methane and the flow of air, so that the gas concentration in the gas mixing chamber reaches the range of 6%-9%.

[0014] As a further preferred embodiment, the high-concentration methane gas is connected to the fuel flow electronic control valve and the fuel flow meter in sequence through the fuel air guide pipe, and then connected to the front end of the gas mixing chamber; the air is connected to the air flow electronic control valve and the air flow meter in sequence through the air guide pipe through the blower, and then connected to the front end of the gas mixing chamber. According to actual needs, the introduced high-concentration methane gas or air is fully mixed with the gas gas entering the gas mixing chamber through the gas valve in the gas mixing chamber equipped with stainless steel wire corrugated packing, and finally leads to the mixed gas outlet.

[0015] As a further preferred embodiment, the gas mixing chamber is preferably a "tapered tube" design, which has a relatively symmetrical structure, which is conducive to uniform distribution of the mixed gas therein and obtains a better mixing effect. This "tapered tube" design increases the gas flow rate when the mixed gas flows into the anti-flashback chamber, which can prevent flashback.

[0016] As a further preferred embodiment, the gas mixing chamber is equipped with several layers of horizontally and vertically placed stainless steel wire corrugated packings with different pore sizes. The gas is cut and remixed in the mixing chamber to be fully premixed.

[0017] As a further preference, the jet angle of the gas mixing chamber of the "tapered tube" design is 45°.

[0018] As a further preferred embodiment, the material of the anti-flashback device is gravel. Since high temperature cannot penetrate low-temperature gravel in a short period of time, the flame cannot reach the combustion temperature when it reaches the gravel and is automatically extinguished, thereby achieving flame retardancy.

[0019] As a further preferred embodiment, the length of the tapered section in the Venturi tube channel is greater than the length of the divergent section.

[0020] As a further preference, the Venturi tubes are consistent in size and shape.

[0021] As a further preferred embodiment, the fuel flow electronic control valve, the air flow electronic control valve, the gas concentration detector and the backfire signal tester are all controlled by a control system.

[0022] The beneficial effects of the present invention are:

[0023] 1. By setting up a gas concentration detector controlled by the control system, a fuel flow electronic control valve and an air flow electronic control valve, in combination with a high-concentration methane storage tank and a blower, when the gas concentration is lower than 6%, high-concentration methane can be introduced into the gas mixing chamber, and when the gas concentration is higher than 9%, air can be introduced into the gas mixing chamber to obtain a mixed gas of the required concentration; and the stainless steel wire corrugated filler in the gas mixing chamber can fully premix the mixed gas and then transport it to the combustion chamber for combustion through the anti-flashback chamber, thereby improving the stability and uniformity of the mixed gas.

[0024] 2. The triple anti-flashback mechanism is set up, which applies the Venturi effect. The flow rate of the mixed gas is accelerated when it enters the anti-flashback chamber from the gas mixing chamber with a "tapered tube" design, thereby preventing the occurrence of flashback; an anti-flashback device is set up in the anti-flashback channel using the characteristics of gravel, and a flashback signal detector is installed; the Venturi tube is formed by using the expansion and contraction grid plate, which further enhances the flashback effect.

[0025] 3. By setting up relevant flue gas recovery devices, the gases emitted after combustion are collected and discharged to the surrounding of the anti-backfire chamber to preheat the premixed gas.

[0026] 4. In addition, the burner provided in this embodiment does not contain any expensive instruments, the device is highly practical, saves equipment costs, and is easy and convenient to operate.

[0027] 5. Therefore, by using this combustion device to treat low-concentration coal mine gas generated during coal mining, the emission of concentrated coal mine gas can be reduced. BRIEF DESCRIPTION OF THE DRAWINGS

[0028] Figure 1 It is a cross-sectional view of a safe and stable burner for premixed gas with a wide concentration range provided in accordance with a preferred embodiment of the present invention;

[0029] Figure 2 It is a topological diagram of a safe and stable burner of premixed gas with a wide concentration range provided in accordance with a preferred embodiment of the present invention;

[0030] Figure 3 yes Figure 1 Partial view of section A;

[0031] Figure 4 yes Figure 1 A partial view of section B;

[0032] Figure 5 yes Figure 1 Partial view of section C.

[0033] In the figure: 1-high concentration methane storage tank; 2-fuel air duct; 3-fuel flow electronic control valve; 4-fuel flow meter; 5-blower; 6-air duct; 7-air flow electronic control valve; 8-air flow meter; 9-gas valve; 10-gas mixing chamber; 11-full premixing chamber; 12-gas concentration detector; 13-stainless steel wire corrugated packing; 14-anti-flashback chamber; 15-anti-flashback channel; 16-anti-flashback device; 17-flashback signal detector; 18-gas concentration detector; 19-expansion and contraction grid; 20-venturi tube; 21-combustion chamber; 22-gradually contracting flue gas collection device; 23-smoke duct; 24-annular pipe; 25-chimney; 26-control system. DETAILED DESCRIPTION

[0034] In order to make the purpose, technical solutions and advantages of the present invention more clearly understood, the present invention is further described in detail below in conjunction with the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are only used to explain the present invention and are not intended to limit the present invention. In addition, the technical features involved in each embodiment of the present invention described below can be combined with each other as long as they do not conflict with each other.

[0035] like Figure 1-5 As shown, the present invention proposes a safe and stable premixed gas burner with a wide concentration range, which is equipped with a high-concentration methane storage tank and a blower, a fuel flow electronic control valve and an air flow electronic control valve, a fuel flow meter and an air flow meter, a gas intake valve, a fully premixing chamber, an anti-flashback chamber, a combustion chamber, a gradually contracting flue gas collection device, a flue gas guide pipe, a ring pipe and a chimney in sequence along the gas flow direction. Among them:

[0036] The high-concentration methane storage tank 1 and the blower 5 are connected to the fully premixing chamber 11 through the fuel air guide pipe 2 and the air conduit 6. The gas intake valve 9 is connected to the fully premixing chamber 11.

[0037] The fully premixing chamber 11 is used to obtain premixed gas and send it to the anti-flashback chamber 14. The fully premixing chamber 11 includes: a fuel air duct 2 connected to the high-concentration methane storage tank 1, an air duct 6 connected to the blower 5, a gas intake valve 9, a gas mixing chamber 10 equipped with several layers of horizontally and vertically placed stainless steel wire corrugated fillers 13 with different pore sizes, and a gas concentration detector 12. The fuel air duct 2 connected to the high-concentration methane storage tank 1 and the air duct 6 connected to the blower 5 are connected to the fully premixing chamber 11 and the injection angle is 110°.

[0038] The anti-backfire chamber 14 is used to deliver the premixed gas into the combustion chamber 21 and prevent the occurrence of backfire. It is installed after the fully premixed chamber 11, and a gas concentration tester 18 is also installed in it to further detect the concentration of the mixed gas that is about to enter the combustion chamber 21. In the anti-backfire channel 15, there are anti-backfire devices 16, backfire signal detectors 17, gas concentration detectors 18 and venturi tubes 20 formed by expansion and contraction grids 19, which are installed in sequence along the gas flow direction. The anti-backfire device 16 can allow the flame to reach this point. Due to the characteristics of the material, the flame temperature is rapidly reduced, and the shape of the flame is broken up, so that its combustion speed is rapidly reduced. Due to the reduction in the combustion speed, the air flow speed is greater than the combustion speed, and it is difficult to flash back. The backfire signal detector 17 is used to detect backfire. When a flame signal is detected in the burner, the control system immediately cuts off the fuel flow electronic control valve 3. In order to confirm again that the concentration of the premixed gas reaches the expected value, a gas concentration detector 18 is placed to detect the concentration of the mixed gas for a second time. An expansion and contraction grid plate 19 is arranged in the anti-flashback channel 15. The expansion and contraction grid plate 19 forms a preset number of venturi tube channels 20 in the anti-flashback channel 15 to enhance the anti-flashback effect.

[0039] The combustion chamber 21 is installed after the anti-flashback chamber 14 for igniting the premixed gas.

[0040] The gradually contracting flue gas collecting device 22 is used to collect the flue gas emitted after combustion and discharge it to the annular pipe 24 on the outer layer of the anti-flashback chamber 14 through the flue gas duct 23, so as to preheat the premixed gas in the anti-flashback chamber in advance and finally discharge it through the chimney 25.

[0041] Furthermore, the jet angle of the gas mixing chamber 10 of the "converging tube" design is 45°. Furthermore, the material of the anti-flashback device 16 is gravel with many holes. Since high temperature cannot penetrate the cool gravel in a short time, the gravel heats up slowly, and the flame reaches the gravel and does not reach the combustion temperature and automatically extinguishes, thereby achieving flame retardancy; the length of the converging section in the venturi tube 20 channel is greater than the length of the expanding section, and the size and shape of each venturi tube 20 are consistent.

[0042] According to a preferred embodiment of the present invention, the fuel air duct and the air air duct are arranged at the front end of the premixing chamber, the diameter of the fuel air duct and the air air duct is 65mm and the inlet direction is parallel to the axis of the burner; the shape of the adjustable concentration fully premixing chamber is a truncated cone with a length of 0.5m, the mixed air inlet of the premixing chamber is a circle with a cross-sectional radius of 1.5m, and the mixed air outlet of the premixing chamber is a circle with a cross-sectional radius of 1.2m; the jet angle of the gas mixing chamber of the "tapered tube" design is 45°; the anti-flashback chamber is 0.5m long and has a cross-sectional radius of The length of the tapered section in the Venturi duct formed in the anti-backfire channel is twice the length of the gradually expanding section; the combustion chamber is a cube with a depth of 2.84m, a width of 3.4m and a height of 1.2m. A circle with a cross-sectional radius of 0.8m is opened on the air inlet cross section as the air inlet of the combustion chamber, and the air outlet of the combustion chamber is a rectangle with a cross-sectional area of ​​1.2m×3.4m; the tapered flue gas collection device adopts a "tapered" structure, and its outlet cross-section is a circle with a radius of 0.1m, and the diameters of the flue gas guide pipe and the annular pipe are 0.1m.

[0043] The specific working process of the safe and stable premixed gas burner with a wide concentration range provided by the present invention is described in detail below: the high-concentration methane storage tank 1 is connected to the fuel flow electronic control valve 3 and the fuel flow meter 4 in sequence through the fuel air guide pipe 2, and finally connected to the gas mixing chamber 10 through the gas mixing inlet; the air passes through the blower 5 and the air conduit 6 to connect the air flow electronic control valve 7 and the air flow meter 8 in sequence, and finally connected to the gas mixing chamber 10 through the gas mixing chamber inlet. The gas intake valve 9 is connected to the gas mixing chamber 10. First, the air flow electronic control valve 7 is opened and injected into the air through the control system 26 to fill the entire burner with air. When it is ensured that the air fills the combustion chamber, the air flow electronic control valve 7 is closed. The gas intake valve 9 is opened to deliver low-concentration methane to the gas mixing chamber 10. The control system 26 automatically adjusts the ratio of gas to air by controlling the gas concentration detector 12, the fuel flow electronic control valve 3 and the air flow electronic control valve 7 installed in the fully premixed chamber 11, so as to achieve the concentration requirements of the required premixed gas. When the gas concentration detector 12 detects that the gas concentration in the gas mixing chamber is lower than 6%, the fuel flow electronic control valve 3 is automatically started to deliver high-concentration methane to the gas mixing chamber; when the gas concentration detector 12 detects that the gas concentration in the gas mixing chamber is higher than 9%, the air flow electronic control valve 3 is automatically started to deliver air to the gas mixing chamber. The mixed gas is cut and remixed by the stainless steel wire corrugated filler 13 in the gas mixing chamber 10 to complete full premixing. Then, the fully premixed gas enters the anti-flashback passage 15 of the anti-flashback chamber 14 through the outlet of the gas mixing chamber 10, passes through the anti-flashback device 16 of the anti-flashback chamber 14, undergoes flashback detection by the flashback detector 17 and concentration detection by the gas concentration detector 18, flows through the venturi tube 20 formed by the expansion and contraction grid plate 19, and enters the combustion chamber 21 through the combustion chamber inlet. The smoke after combustion passes through the gradually contracting smoke collection device and is discharged to the annular pipe 24 of the outer layer of the anti-flashback chamber 14 through the smoke guide pipe 23, and the premixed gas in the anti-flashback chamber is preheated in advance and finally discharged through the chimney 25. It is easy for those skilled in the art to understand that the above description is only a preferred embodiment of the present invention and is not intended to limit the present invention. Any modifications, equivalent substitutions and improvements made within the spirit and principle of the present invention should be included in the protection scope of the present invention.

Claims

1. A safe and stable burner for premixed gas with a wide concentration range, characterized in that: include: A high-concentration methane storage tank (1) and a blower (5), a fuel flow electronic control valve (3) and an air flow electronic control valve (7), a fuel flow meter (4) and an air flow meter (8), a gas intake valve (9), a fully premixing chamber (11), an anti-flashback chamber (14), a combustion chamber (21), a tapered flue gas collection device (22), a flue gas guide pipe (23), a ring pipe (24) and a chimney (25) are sequentially connected along the gas flow direction. Among them: According to the high-concentration methane storage tank (1) and the blower (5), the fuel flow electronic control valve (3) and the air flow electronic control valve (7), the fuel flow meter (4) and the air flow meter (8) cooperate with the gas concentration detector (12) of the fully premixing chamber (11) to quickly adjust the intake air concentration. The fully premixing chamber (11) is used to send the obtained premixed gas into the anti-flashback chamber (14). The fully premixing chamber (11) comprises: a fuel gas pipe (2) connected to a high-concentration methane storage tank (1), an air duct (6) connected to a blower (5), a gas intake valve (9), a gas mixing chamber (10) equipped with a plurality of layers of horizontally and vertically placed stainless steel wire corrugated fillers (13) with different pore sizes, and a methane concentration detector (18). The anti-flashback chamber (14) is used to deliver the premixed gas into the combustion chamber (21) and prevent flashback, and comprises an anti-flashback passage (15), an anti-flashback device (16), a flashback signal detector (17), a methane concentration detector (18) and a venturi tube (20) formed by an expansion and contraction grid plate (19). The combustion chamber (21) is used to ignite the premixed gas so that the premixed gas burns therein. The gradually contracting flue gas collecting device (22) is used to collect the flue gas discharged after combustion and discharge it to the outer annular pipe (24) of the anti-flashback chamber (14) through the flue gas guide pipe (23), preheat the premixed gas in the anti-flashback chamber in advance, and finally discharge it through the chimney (25). The fuel flow electronic control valve (3), the air flow electronic control valve (7), the flashback signal detector (17), the gas concentration detector (12) in the fully premixing chamber (11) and the gas concentration detector (18) in the anti-flashback chamber are all controlled by the control system (26).

2. A safe and stable burner for premixed gas with a wide concentration range according to claim 1, characterized in that: The output ends of the fuel flow electronic control valve (3) and the air flow electronic control valve (7) are wirelessly connected to the control system (26).

3. A safe and stable burner for premixed gas with a wide concentration range according to claim 1, characterized in that: The gas mixing chamber (10) of the fully premixing chamber (11) is preferably of a "tapered tube" design.

4. A safe and stable burner for premixed gas with a wide concentration range according to claim 3, characterized in that: The jet angle of the gas mixing chamber (10) of the "converging tube" design is 45°.

5. A safe and stable burner for premixed gas with a wide concentration range according to claim 1, characterized in that: The methane concentration detector (12) of the fully premixing chamber is used to detect whether the gas concentration in the fully premixing chamber is within the range of 6%-9%. Its output end is wirelessly connected to the control system and operates in coordination with the fuel flow electronic control valve (3) and the air flow electronic control valve (7).

6. A safe and stable burner for premixed gas with a wide concentration range according to claim 1, characterized in that: The material of the anti-flashback device (16) is gravel.

7. A safe and stable burner for premixed gas with a wide concentration range according to claim 1, characterized in that: The output end of the flashback signal detector (17) is wirelessly connected to the control system (26).

8. A safe and stable burner for premixed gas with a wide concentration range according to claim 1, characterized in that: The methane concentration detector (18) of the anti-flashback chamber is used to perform secondary detection on the premixed gas mixture, and its output end is wirelessly connected to the control system (26).

9. A safe and stable burner for premixed gas with a wide concentration range according to claim 1, characterized in that: The length of the gradually contracting section in the passage of the venturi tube (20) is greater than the length of the gradually expanding section, and the sizes, sizes and shapes are consistent.

10. A safe and stable burner for premixed gas with a wide concentration range according to claim 1, characterized in that: The smoke guide pipe (23) and the annular pipe (24) are made of materials that are resistant to high temperatures and have good heat preservation effects.

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