Rotational flow jet flow low-concentration gas flameless oxidation device and method

Abstract

The invention relates to a rotational flow jet flow low-concentration gas flameless oxidation device and method.The rotational flow jet flow low-concentration gas flameless oxidation device comprises an oxidation chamber used for achieving low-concentration gas oxidation and an ignition system arranged in the oxidation chamber, a flame stabilizing disc is arranged at one end of the oxidation chamber, and a high-temperature flue gas outlet is formed in the other end of the oxidation chamber; a rotational flow pipe capable of enabling gas to form turbulent flow in the oxidation chamber is arranged on the oxidation chamber along the circumferential direction of the flame stabilizing disc in a penetrating manner, through holes are formed in the flame stabilizing disc and are communicated with a main gas inlet, the rotational flow pipe is communicated with a secondary gas inlet, the total area of the through holes is smaller than the sectional area of the high-temperature flue gas outlet, and the gas inlet is communicated with the secondary gas inlet. By arranging the rotational flow pipe, backflow of high-temperature flue gas is achieved, the total area of the through holes is set to be smaller than the sectional area of the high-temperature flue gas outlet, gas is stably combusted, in addition, the rotational flow pipe is arranged in the circumferential direction of the flame stabilizing disc, and the gas oxidation effect can be improved.

Description

Technical Field

[0001] The invention belongs to the technical field of efficient coal mine gas control and utilization, and particularly relates to a swirl jet low-concentration gas flameless oxidation device and method. Background Art

[0002] In order to reasonably solve the problem of mine safety, the gas extraction method is usually used to reasonably reduce the exhaust gas to a safe concentration below 1%. However, in the process of coal mine gas extraction in my country, due to the single form of gas extraction, a lot of mixed air, and the fluctuation of extraction volume, most of the extracted gas is low-concentration gas with a concentration below 30%, of which the extracted gas with a concentration below 8% accounts for more than 70% of the total extraction. Because this part of the gas is in the explosive concentration range, it is difficult to stably burn it and efficiently utilize it using conventional combustion methods, and it is discharged into the atmosphere.

[0003] The main component of gas is methane, which has a greenhouse effect equivalent to 24.6 times that of CO2 and a destructive capacity to the atmospheric ozone layer equivalent to 7 times that of CO2. Every year, a large amount of low-concentration gas is released and cannot be used, which not only causes a serious waste of limited non-renewable resources, but also aggravates air pollution and greenhouse effects. As a high-quality energy source, the calorific value of gas combustion is about 35000kJ / Nm3, which is equivalent to conventional natural gas, and can be used as fuel and chemical raw materials. Since oxygen is a combustible auxiliary agent, the introduction of oxygen increases the explosion hazard of coalbed methane, which brings great difficulties to the processing and transportation of coalbed methane. At present, the categories, proportions, utilization rates and main utilization methods of coalbed methane extraction. Among them, medium and high concentration gas (CCH4>30%) accounts for about 6%, and the utilization rate exceeds 90%. Low concentration gas accounts for about 94%, but the utilization rate is less than 35%. Due to the low gas concentration in low-concentration gas, it is difficult to utilize it. Its main utilization methods are thermal storage oxidation and high-concentration gas mixed combustion for power generation. The utilization efficiency of these methods is also relatively low, so most of the low-concentration gas is directly discharged into the atmosphere, causing huge waste of resources. At the same time, the environment has also been greatly damaged.

[0004] Low-concentration gas in the range of 4% to 10% has a thin methane component and is within the explosion limit. It is difficult to achieve stable combustion and efficient utilization through conventional combustion methods, so it is usually discharged directly into the atmosphere, causing great waste of energy and serious environmental pollution. Since the current "Coal Mine Safety Regulations" stipulate that low-concentration gas with a concentration below 30% shall not be directly burned, although there are supplementary explanations, it has limited the research and development, promotion and application of low-concentration gas utilization technology to a certain extent. Although there are some oxidation devices for low-concentration gas, their thermal utilization rate is relatively low.

[0005] Therefore, a low-concentration gas flameless oxidation device and method with a swirl jet are designed. The swirl tube in the oxidation device can achieve strong turbulence in the oxidation chamber, thereby achieving high-temperature flue gas reflux and rapid oxidation of the gas, and destroying the gas deflagration energy wave within the explosion limit and stabilizing the oxidation, thereby achieving flameless oxidation of the gas and improving thermal utilization efficiency. This is a technical problem that technical personnel in this field need to solve. Summary of the invention

[0006] In order to solve the above problems, the present invention provides a swirl jet low-concentration gas flameless oxidation device and method. The swirl tube in the oxidation device can achieve strong turbulence in the oxidation chamber and thus achieve high-temperature flue gas reflux and rapid oxidation of the gas, and destroy the gas deflagration energy wave within the explosion limit and stabilize the oxidation, thereby achieving flameless oxidation of low-concentration gas.

[0007] To achieve the above object, the present invention provides the following solutions:

[0008] A swirl jet low-concentration gas flameless oxidation device comprises an oxidation chamber for realizing low-concentration gas oxidation, and an ignition system arranged in the oxidation chamber, a flame stabilizing disk is arranged at one end of the oxidation chamber, a high-temperature flue gas outlet is opened at the other end of the oxidation chamber, a swirl tube which can make the gas form turbulence in the oxidation chamber is penetrated on the oxidation chamber along the circumference of the flame stabilizing disk, and a through hole is arranged on the flame stabilizing disk on the circumference, the through hole is connected to the main air inlet, the swirl tube is connected to the secondary air inlet, and the total area of ​​the through hole is smaller than the cross-sectional area of ​​the high-temperature flue gas outlet.

[0009] Preferably, the swirl tube is connected to the secondary air inlet through an arc-shaped gas distribution pipe, and the distance between the swirl tube outlet and the cross-section of the flame stabilizing disk is 1 / 10 to 1 / 5 of the length of the oxidation chamber.

[0010] Preferably, two or more irregular direct current jet nozzles are provided on the oxidation chamber along the circumference of the flame stabilizing disk, and the direct current jet nozzles are connected to the main air inlet.

[0011] Preferably, a device for changing the gas jet angle and regulating the flow rate is provided in the swirl tube.

[0012] Preferably, it also includes an initial oxidation temperature monitoring system arranged inside the oxidation chamber near one end of the flame stabilizing disk, an oxidation main body temperature monitoring system arranged near the middle of the oxidation chamber, and a flame monitoring system arranged inside the oxidation chamber.

[0013] Preferably, the outer periphery of the oxidation chamber is provided with a heat storage body and a heat insulation layer in sequence from the inside to the outside.

[0014] Preferably, a gas inlet is provided at the center of the flame stabilizing disk, a switch for opening and closing the gas inlet is provided at the end of the gas inlet, and the gas inlet is connected to a gas pipe provided in the middle of the secondary air inlet.

[0015] Preferably, the total area of ​​the through holes is 1 / 3 to 1 / 2 of the cross-sectional area of ​​the high-temperature flue gas outlet.

[0016] The present invention also discloses a swirl jet low-concentration gas flameless oxidation method, which uses the swirl jet low-concentration gas flameless oxidation device as described above, and comprises the following steps:

[0017] The gas enters the oxidation chamber through the main air inlet, the fire stabilizing plate and the direct current jet nozzle, and is ignited by the ignition system;

[0018] When the temperature of the oxidation chamber rises, air is introduced from the secondary air inlet and gas is sprayed into the oxidation chamber through the cyclone tube, so that the gas is rapidly oxidized at high temperature.

[0019] Preferably, when the temperature of the oxidation chamber is lower than 600° C. and the flue gas reflow ratio is lower than 60%, gas with a volume concentration higher than 6% shall not enter the oxidation device through the DC jet nozzle.

[0020] Compared with the prior art, the present invention has achieved the following technical effects:

[0021] By setting a swirl tube, the gas introduced from the secondary air inlet can form turbulence in the oxidation chamber, so that the gas can be quickly oxidized and the high-temperature flue gas can be refluxed, thereby ensuring the flameless oxidation of the gas. The total area of ​​the through hole is set to be smaller than the cross-sectional area of ​​the high-temperature flue gas outlet, so that the gas entering from the through hole can have a certain pressure, and the gas that forms turbulence after passing through the swirl tube is avoided. The gas that is burned in the through hole is not disturbed, causing the fire at the flame stabilizing disk to be unstable, thereby ensuring the gas to burn stably. In addition, the swirl tube is set on the circumference of the flame stabilizing disk. After being ignited by the flame stabilizing disk, the temperature reaches the set value, and then the gas is sprayed through the swirl tube, that is, the gas introduced from the swirl tube is sprayed out from the circumference of the flame stabilizing disk, which can increase the contact area between the gas sprayed from the swirl tube and the burning gas sprayed from the flame stabilizing disk, so that the gas can be instantly oxidized, thereby improving the gas oxidation effect, and the thermal utilization rate of the flameless oxidation device of the present invention can be increased by more than 10%. BRIEF DESCRIPTION OF THE DRAWINGS

[0022] In order to more clearly illustrate the technical solutions in the present invention or the prior art, the drawings required for use in the embodiments will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying creative labor.

[0023] AttachedFigure 1 It is a schematic diagram of the overall structure of a swirl jet low-concentration gas flameless oxidation device and method disclosed in an embodiment of the present invention;

[0024] Among them, 1. main air inlet; 2. DC jet nozzle; 3. flame stabilizing disk; 4. secondary air inlet; 41. fuel gas pipe; 5. gas distribution pipe; 6. swirl pipe; 7. heat storage body; 8. ignition system; 9. initial oxidation temperature monitoring system; 10. oxidation chamber; 11. oxidation body temperature monitoring system; 12. high-temperature flue gas outlet; 13. thermal insulation layer. DETAILED DESCRIPTION

[0025] The following will be combined with the drawings in the embodiments of the present invention to clearly and completely describe the technical solutions in the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0026] The object of the present invention is to provide a swirl jet low-concentration gas flameless oxidation device and method. Through the swirl tube 6 in the oxidation device, strong turbulence can be achieved in the oxidation chamber 10, thereby achieving high-temperature flue gas reflux and rapid oxidation of the gas, and destroying the gas deflagration energy wave within the explosion limit and stabilizing the oxidation, thereby achieving flameless oxidation of low-concentration gas.

[0027] In order to make the above-mentioned objects, features and advantages of the present invention more obvious and easy to understand, the present invention is further described in detail below with reference to the accompanying drawings and specific embodiments.

[0028] refer to Figure 1The swirl jet low-concentration gas flameless oxidation device disclosed in the embodiment of the present invention at least includes an oxidation chamber 10 for realizing low-concentration gas oxidation, an ignition system 8 is arranged in the oxidation chamber 10, a flame stabilizing disk 3 is arranged at one end of the oxidation chamber 10, and a high-temperature flue gas outlet 12 is opened at the other end of the oxidation chamber 10. A swirl tube 6 that can make the gas form turbulence in the oxidation chamber 10 is penetrated along the circumference of the flame stabilizing disk 3 on the oxidation chamber 10, and the flame stabilizing disk 3 is provided with a through hole, which is connected to the main air inlet 1, and the swirl tube 6 is connected to the secondary air inlet 4. The total area of ​​the through hole is smaller than the cross-sectional area of ​​the high-temperature flue gas outlet 12. By providing the swirl tube 6, the gas introduced from the secondary air inlet 4 can form turbulence in the oxidation chamber 10, so that the gas is quickly oxidized and the reflux of the high-temperature flue gas is realized. , thereby ensuring flameless oxidation of the gas, setting the total area of ​​the through hole to be smaller than the cross-sectional area of ​​the high-temperature flue gas outlet 12, can ensure that the gas entering from the through hole has a certain pressure, avoid the gas forming turbulence after passing through the swirl tube 6, and form disturbances on the gas burning from the through hole, so that the fire root at the flame stabilizing disk 3 is unstable, thereby making the gas burn stably, in addition, the swirl tube 6 is arranged on the circumference of the flame stabilizing disk 3, when the temperature reaches the set value after being ignited by the flame stabilizing disk 3, and then the gas is sprayed through the swirl tube 6, that is, the gas introduced from the swirl tube 6 is sprayed out from the circumference of the flame stabilizing disk 3, which can increase the contact area between the gas sprayed from the swirl tube 6 and the burning gas sprayed from the flame stabilizing disk 3, so that the gas can be instantly oxidized, thereby improving the gas oxidation effect;

[0029] It should be noted that: the axis of the flame stabilizing disk 3 coincides with the axis of the high-temperature flue gas outlet 12, the flame stabilizing disk 3 can be provided as one or more, the oxidation chamber 10 and the high-temperature flue gas outlet 12, the main air inlet 1, the secondary air inlet 4, etc. can be square or circular, and the swirl tube 6 can be a pipe with a diameter gradually reduced along the gas inlet direction, as long as the gas can form turbulent flow inside the oxidation chamber 10;

[0030] The cross-sections of the oxidation chamber 10 and the high-temperature flue gas outlet 12 adopt a variable diameter structure to enhance the reflow of the high-temperature flue gas. Preferably, the cross-sections of the oxidation chamber 10 and the high-temperature flue gas outlet 12 can be a sudden change or a cambered transition.

[0031] refer to Figure 1 As an implementation mode, flow control meters for controlling the gas flow are provided in the secondary air inlet 4 and the main air inlet 1. By providing flow control meters in the main air inlet 1 and the secondary air inlet 4, the intake volume and pressure of the main air inlet 1 and the secondary air inlet 4 can be changed to change the ratio of the dynamic pressure of the jet.

[0032] refer to Figure 1As an implementation mode, the swirl tube 6 is connected to the secondary air inlet 4 through the arc-shaped gas distribution pipe 5, and the distance between the air outlet of the swirl tube 6 and the end face of the flame stabilizing disk 3 is 1 / 10 to 1 / 5 of the length of the oxidation chamber 10. By arranging the arc-shaped gas distribution pipe 5 between the secondary air inlet 4 and the swirl tube 6, the turbulent effect of the gas entering the oxidation chamber 10 can be further guaranteed, and the distance between the air outlet of the swirl tube 6 and the flame stabilizing disk 3 can be set to ensure that there is a certain length from the air outlet of the swirl tube 6 to the high-temperature flue gas outlet 12, thereby improving the turbulent effect of the gas in the oxidation chamber 10.

[0033] refer to Figure 1 As an implementation mode, two or more irregular DC jet nozzles 2 are provided on the oxidation chamber 10 along the circumference of the flame stabilizing disk 3, and the DC jet nozzles 2 are connected to the main air inlet 1. By providing the DC jet nozzles 2, the gas ejected from the DC jet nozzles 2 and the gas ejected from the flame stabilizing disk 3 can form a cross collision, thereby decelerating the gas and ensuring that the gas is fully ignited in the oxidation chamber 10.

[0034] refer to Figure 1 As an implementation method, a regulating device for changing the gas jet angle and flow rate is provided in the cyclone tube 6, thereby changing the jet intensity and adjusting the entrainment and reflux of the high-temperature flue gas in the oxidation chamber 10;

[0035] It should be noted that the regulating device can control the flow rate of the flow control meter and the baffle plate hingedly arranged in the swirl tube 6, and the baffle plate is provided with a paddle for controlling the angle adjustment of the baffle plate. The angle of the baffle plate can be adjusted by paddle, thereby adjusting the jet angle of the swirl tube 6.

[0036] refer to Figure 1 As an embodiment, it also includes an initial oxidation temperature monitoring system 9 arranged inside the oxidation chamber 10 near one end of the flame stabilizing disk 3, and an oxidation main body temperature monitoring system 11 arranged near the middle of the oxidation chamber 10. By setting the initial oxidation temperature monitoring system 9 and the oxidation main body temperature monitoring system 11, the temperature at different positions in the oxidation chamber 10 can be monitored, thereby providing signals for opening and closing the flow meter, and opening and closing the main air inlet 1 and the secondary air inlet 4;

[0037] It should be noted that the initial oxidation temperature monitoring system 9 can monitor flame signals, temperature signals, or both flame and temperature signals. Flame signal monitoring can use one or more of ion probes, infrared, and ultraviolet. By real-time monitoring of the flame state in the oxidation system, once an abnormal flame or flame extinction is detected, corresponding measures can be taken immediately, such as alarming, stopping gas supply, or starting a fire extinguishing device.

[0038] refer to Figure 1The outer periphery of the oxidation chamber 10 is provided with a heat storage body 7 and a heat insulation layer 13 from the inside to the outside. The heat storage body 7 is used to store heat in the oxidation chamber 10, and the heat insulation layer 13 can prevent heat loss. By arranging the heat storage body 7 between the oxidation chamber 10 and the heat insulation layer 13, the heat storage effect can be greatly improved. There is no need to set up additional heat storage materials, which can greatly improve the compactness of the device.

[0039] refer to Figure 1 As an implementation mode, a plurality of through holes are provided and are evenly arranged in the circumferential direction of the flame stabilizing disk 3. The distance between each through hole and the center of the flame stabilizing disk 3 is the same. The angle between the extension line of the through hole along the gas inlet direction and the extension line of the axis of the flame stabilizing disk 3 toward the oxidation chamber 10 is an acute angle. Setting the axial angle between the through hole and the flame stabilizing disk 3 as an acute angle can ensure that the gas entering from the through hole can cross and collide with each other, thereby slowing down the gas and ensuring that the gas is fully ignited in the oxidation chamber 10.

[0040] refer to Figure 1 In one embodiment, a gas inlet is provided at the center of the flame stabilizing disk 3, and a switch for opening and closing the gas inlet is provided at the end of the gas inlet. The gas inlet is connected to a gas pipe 41 provided at the middle of the secondary air inlet 4. By connecting the gas inlet with the gas pipe 41, when there is no gas, natural gas can be introduced through the secondary air inlet 4 and the gas inlet in sequence, and the main air inlet 1 can be ventilated, thereby realizing the dual use of gas and natural gas;

[0041] It should be noted that when the gas is introduced, the gas inlet is in an open state, and when the gas is introduced, the gas inlet is in a closed state, and the inner diameter of the gas inlet is larger than the inner diameter of the through hole.

[0042] refer to Figure 1 In one embodiment, the total area of ​​the through holes is 1 / 3 to 1 / 2 of the cross-sectional area of ​​the high-temperature flue gas outlet 12 .

[0043] refer to Figure 1 The present invention also discloses a swirl jet low-concentration gas flameless oxidation method, using the swirl jet low-concentration gas flameless oxidation device described above, and its main steps are:

[0044] The gas enters the oxidation chamber 10 through the main air inlet 1, the through hole and the direct current injection port, and is ignited by the ignition system 8;

[0045] After the initial oxidation temperature monitoring system 9 detects that the temperature of the oxidation chamber 10 is higher than 600°C, the secondary air inlet 4 is opened to introduce gas, and gas is injected into the oxidation chamber 10 through the gas distribution pipe 5 and the cyclone pipe 6, and the gas is rapidly oxidized at high temperature;

[0046] The heat storage body 7 and the heat insulation layer 13 are used to store heat and reduce heat dissipation losses. The high-temperature flue gas is discharged through the high-temperature flue gas outlet 12 to provide a heat source for heat users;

[0047] To ensure safety, the initial oxidation temperature monitoring system 9 and the oxidation main body temperature monitoring system 11 are interlocked with the gas intake regulating device;

[0048] High-temperature flue gas entrainment is achieved through a strong swirl jet, so that the gas is oxidized in a very short time. The gas concentration field and temperature field gradient in the oxidation chamber 10 are small, so there is no obvious flame surface.

[0049] When gas is introduced into the secondary air inlet 4, the gas inlet is opened by a switch, and the gas passes through the secondary air inlet 4, the gas pipe 41, and the gas inlet in sequence into the oxidation chamber 10. The through hole and the DC jet nozzle 2 are used to connect with the outside air to realize the combustion of the gas.

[0050] refer to Figure 1 As an implementation mode, when the temperature of the oxidation chamber 10 is lower than 600° C. and the flue gas recirculation ratio is lower than 60%, gas with a volume concentration higher than 6% shall not enter the oxidation device through the DC jet nozzle 2.

[0051] Adaptive changes made according to actual needs are all within the protection scope of the present invention.

[0052] It should be noted that it is obvious to those skilled in the art that the present invention is not limited to the details of the exemplary embodiments described above, and that the present invention can be implemented in other specific forms without departing from the spirit or essential features of the present invention. Therefore, the embodiments should be regarded as exemplary and non-restrictive from any point of view, and the scope of the present invention is defined by the appended claims rather than the above description, and it is intended that all changes falling within the meaning and scope of the equivalent elements of the claims be included in the invention. Any reference numeral in a claim should not be regarded as limiting the claim to which it relates.

Claims

1. A swirl jet low-concentration gas flameless oxidation device, characterized in that: It includes an oxidation chamber for realizing low-concentration gas oxidation, and an ignition system arranged in the oxidation chamber, wherein a flame stabilizing disk is arranged at one end of the oxidation chamber, and a high-temperature flue gas outlet is opened at the other end of the oxidation chamber, and a swirl tube which can make the gas form turbulence in the oxidation chamber is penetrated on the oxidation chamber along the circumference of the flame stabilizing disk, and the flame stabilizing disk is provided with a through hole, which is connected to the main air inlet, and the swirl tube is connected to the secondary air inlet, and the total area of ​​the through hole is smaller than the cross-sectional area of ​​the high-temperature flue gas outlet.

2. The swirl jet low-concentration gas flameless oxidation device according to claim 1 is characterized in that: The swirl tube is connected to the secondary air inlet through an arc-shaped gas distribution pipe, and the distance between the swirl tube outlet and the flame stabilizing disk is 1 / 10 to 1 / 5 of the length of the oxidation chamber.

3. The swirl jet low-concentration gas flameless oxidation device according to claim 1 is characterized in that: Two or more irregular direct current jet nozzles are arranged on the oxidation chamber along the circumference of the flame stabilizing disk, and the direct current jet nozzles are connected to the main air inlet.

4. The swirl jet low-concentration gas flameless oxidation device according to claim 1, characterized in that: The swirl tube is provided with a regulating device for changing the gas jet angle and flow rate.

5. The swirl jet low-concentration gas flameless oxidation device according to claim 1, characterized in that: It also includes an initial oxidation temperature monitoring system arranged inside the oxidation chamber near one end of the flame stabilizing disk, and an oxidation main body temperature monitoring system arranged near the middle of the oxidation chamber.

6. The swirl jet low-concentration gas flameless oxidation device according to claim 1, characterized in that: The outer periphery of the oxidation chamber is provided with a heat storage body and a heat insulation layer in sequence from the inside to the outside.

7. The swirl jet low-concentration gas flameless oxidation device according to claim 1, characterized in that: A gas inlet is provided at the center of the flame stabilizing disk, a switch for opening and closing the gas inlet is provided at the end of the gas inlet, and the gas inlet is connected to a gas pipe provided in the middle of the secondary air inlet.

8. The swirl jet low-concentration gas flameless oxidation device according to claim 1, characterized in that: The total area of ​​the through holes is 1 / 3 to 1 / 2 of the cross-sectional area of ​​the high-temperature flue gas outlet.

9. A swirl jet low-concentration gas flameless oxidation method, using the swirl jet low-concentration gas flameless oxidation device as claimed in any one of claims 1 to 8, characterized in that: The following steps are involved: The gas enters the oxidation chamber through the main air inlet, the fire stabilizing plate and the direct current jet nozzle, and is ignited by the ignition system; When the temperature of the oxidation chamber rises, air is introduced from the secondary air inlet and gas is sprayed into the oxidation chamber through the cyclone tube, so that the gas is rapidly oxidized at high temperature.

10. The swirl jet low-concentration gas flameless oxidation method according to claim 9, characterized in that: When the temperature of the oxidation chamber is lower than 600°C and the flue gas reflow ratio is lower than 60%, gas with a volume concentration higher than 6% shall not enter the oxidation device through the DC jet nozzle.

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