Direct-current jet flow low-concentration gas flameless oxidation device and method

Abstract

The invention relates to a direct-current jet flow low-concentration gas flameless oxidation device and method.The direct-current 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 direct flow jet flow nozzle is formed in the oxidizing chamber in the circumferential direction of the flame stabilizing disc, through holes are formed in the flame stabilizing disc, the direct flow jet flow nozzle is communicated with a main air inlet, the through holes are communicated with an auxiliary air inlet, the total area of the through holes is larger than the sectional area of the high-temperature flue gas outlet, and section mutation is formed through the position of the high-temperature flue gas outlet. And the direct-flow nozzle can also realize rapid oxidation of the gas in the oxidation chamber to form turbulent flow, so that backflow of high-temperature flue gas is realized, and the purpose of flameless oxidation of the gas is achieved.

Description

Technical Field

[0001] The invention belongs to the technical field of efficient coal mine gas control and utilization, and particularly relates to a direct current 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 CO 2 The destructive power of CO to the atmospheric ozone layer is 24.6 times that of 2 Every year, a large amount of low-concentration gas is released but cannot be used, which not only causes a serious waste of limited non-renewable resources, but also aggravates air pollution and greenhouse effect. As a high-quality energy source, the calorific value of gas combustion is about 35000kJ / Nm 3 , which is comparable 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 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, resulting in a 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, it is a technical problem that technicians in this field need to solve to design a flameless oxidation device and method for low-concentration gas with a swirl jet, realize high-temperature flue gas reflux and rapid oxidation of gas through strong turbulence in the oxidation device, destroy the gas deflagration energy wave within the explosion limit, and stabilize the oxidation, thereby realizing flameless oxidation of low-concentration gas and improving thermal utilization. Summary of the invention

[0006] In order to solve the above problems, the present invention provides a direct current jet low-concentration gas flameless oxidation device and method. Through the sudden change of the cross-section of the high-temperature flue gas outlet in the oxidation device, the gas in the oxidation chamber can achieve strong turbulence 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, stabilize the oxidation, and achieve flameless oxidation of low-concentration gas.

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

[0008] A DC 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 DC jet nozzle is opened on the oxidation chamber along the circumference of the flame stabilizing disk, a through hole is arranged on the flame stabilizing disk, the DC jet nozzle is connected with a main air inlet, the through hole is connected with an auxiliary air inlet, and the total area of ​​the through hole is larger than the cross-sectional area of ​​the high-temperature flue gas outlet.

[0009] Preferably, flow control meters for controlling the gas flow are provided in both the auxiliary air inlet and the main air inlet.

[0010] 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.

[0011] 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.

[0012] Preferably, the number of the through holes is two or more, the through holes are evenly distributed in the circumferential direction of the flame stabilizing disk, and the distances between two or more of the through holes and the center of the flame stabilizing disk are equal, and 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 toward the oxidation chamber is an acute angle.

[0013] Preferably, the total area of ​​the through holes is 1 to 1.8 times the cross-sectional area of ​​the high-temperature flue gas outlet.

[0014] Preferably, the number of the DC jet nozzles is two or more, and the DC jet nozzles are evenly distributed in the circumferential direction of the end of the oxidation chamber, and the distances between the DC jet nozzles and the center of the flame stabilizing disk are equal.

[0015] The present invention also discloses a direct current jet low-concentration gas flameless oxidation method, which uses the direct current jet low-concentration gas flameless oxidation device as described above, and comprises the following steps:

[0016] The gas enters the oxidation chamber through the auxiliary air inlet and the flame stabilizing plate in sequence and is ignited by the ignition system;

[0017] When the temperature of the oxidation chamber rises, air is taken in from the main air inlet and gas is sprayed into the oxidation chamber through the DC jet nozzle, so that the gas is rapidly oxidized at high temperature.

[0018] Preferably, the ratio of the amount of gas entering the oxidation chamber from the DC jet injection port to the amount of gas entering the oxidation chamber from the flame stabilizing disk is 1 to 6.

[0019] Preferably, after the temperature of the oxidation chamber is higher than 800° C., air is introduced through the main air inlet.

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

[0021] By making the total area of ​​the through holes larger than the cross-sectional area of ​​the high-temperature flue gas outlet and providing a direct current jet nozzle, the area of ​​the air inlet can be increased, which helps to stabilize the intake airflow and reduce airflow fluctuations. Moreover, reducing the cross-sectional area of ​​the high-temperature flue gas outlet can form a cross-sectional mutation in the oxidation chamber at the high-temperature flue gas outlet position, thereby strengthening the reflux of the high-temperature flue gas. The provision of the jet nozzle can also achieve rapid oxidation of the gas in the oxidation chamber, form turbulence, and further achieve the reflux of the high-temperature flue gas, thereby achieving the purpose of flameless oxidation of the gas. In addition, the direct current jet nozzle is provided on the circumference of the flame stabilizing disk. After being ignited by the flame stabilizing disk first, the temperature reaches the set value, and then the gas is sprayed in through the direct current jet nozzle, that is, the gas introduced from the direct current jet nozzle is sprayed out from the circumference of the flame stabilizing disk. The contact area between the gas sprayed from the direct current jet nozzle and the burning gas sprayed from the flame stabilizing disk can be increased, 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 direct current 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. heat storage body; 5. ignition system; 6. initial oxidation temperature monitoring system; 7. oxidation chamber; 8. oxidation main body temperature monitoring system; 9. high-temperature flue gas outlet; 10. thermal insulation layer; 11. auxiliary air inlet. 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 purpose of the present invention is to provide a direct current jet low-concentration gas flameless oxidation device and method, through the cross-sectional mutation of the high-temperature flue gas outlet 9 in the oxidation device, the gas in the oxidation chamber 7 can achieve strong turbulence and thus achieve high-temperature flue gas reflux and rapid oxidation of the gas, and play the role of destroying the gas deflagration energy wave within the explosion limit and stabilizing the oxidation, so that the low-concentration gas can be flamelessly oxidized.

[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 DC jet low-concentration gas flameless oxidation device disclosed in the embodiment of the present invention at least includes an oxidation chamber 7 for realizing low-concentration gas oxidation, an ignition system 5 is arranged in the oxidation chamber 7, a flame stabilizing disk 3 is arranged at one end of the oxidation chamber 7, a high-temperature flue gas outlet 9 is opened at the other end of the oxidation chamber 7, a DC jet nozzle 2 is opened on the oxidation chamber 7 along the circumference of the flame stabilizing disk 3, a through hole is arranged on the flame stabilizing disk 3, the DC jet nozzle 2 is connected with the main air inlet 1, and the through hole is connected with the auxiliary air inlet 11, and the total area of ​​the through hole is larger than the cross-sectional area of ​​the high-temperature flue gas outlet 9. By making the total area of ​​the through hole larger than the cross-sectional area of ​​the high-temperature flue gas outlet 9 and arranging the DC jet nozzle 2, the area of ​​the air inlet can be increased, which helps to stabilize the intake airflow, reduce airflow fluctuations, and reduce high The cross-sectional area of ​​the hot flue gas outlet 9 can also make the oxidation chamber 7 form a cross-sectional mutation at the position of the hot flue gas outlet 9, thereby strengthening the reflux of the hot flue gas. The DC jet nozzle 2 can also realize the rapid oxidation of the gas in the oxidation chamber 7, forming turbulence, further realizing the reflux of the hot flue gas, and achieving the purpose of flameless oxidation of the gas. In addition, the DC jet nozzle 2 is arranged on the circumference of the flame stabilizing disk 3. After the gas is first ignited through the flame stabilizing disk 3, the temperature reaches the set value, and then the gas is sprayed in through the DC jet nozzle 2, that is, the gas introduced from the DC jet nozzle 2 is sprayed out from the circumference of the flame stabilizing disk 3, which can increase the contact area between the gas sprayed from the DC jet nozzle 2 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 9. The flame stabilizing disk 3 can be set to one or more. The oxidation chamber 7 and the high-temperature flue gas outlet 9, the main air inlet 1, the auxiliary air inlet 11, etc. can be square or circular.

[0030] refer to Figure 1 As an implementation mode, flow control meters for controlling the gas flow are provided in the auxiliary air inlet 11 and the main air inlet 1. By providing flow control meters in the main air inlet 1 and the auxiliary air inlet 11, the intake volume and pressure of the main air inlet 1 and the auxiliary air inlet 11 can be changed to change the ratio of the dynamic pressure of the jet.

[0031] refer to Figure 1As an embodiment, it also includes an initial oxidation temperature monitoring system 6 arranged in the oxidation chamber 7 near one end of the flame stabilizing disk 3, an oxidation main body temperature monitoring system 8 arranged in the oxidation chamber 7 near the middle, and a flame monitoring system arranged in the oxidation chamber 7. By setting the initial oxidation temperature monitoring system 6 and the oxidation main body temperature monitoring system 8, the temperature at different positions in the oxidation chamber 7 can be monitored, and then a signal is provided for the opening and closing of the flow meter, the opening and closing of the main air inlet 1 and the auxiliary air inlet 11. The flame monitoring system can monitor both the flame in the oxidation chamber 7 and the temperature in the oxidation chamber 7. 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, etc.;

[0032] It should be noted that the flame monitoring system can monitor flame signals, temperature signals, or flame and temperature signals simultaneously. The flame monitoring system can use one or more of ion probes, infrared, and ultraviolet.

[0033] refer to Figure 1 As an implementation mode, the periphery of the oxidation chamber 7 is provided with a heat storage body 4 and a heat insulation layer 10 in sequence from the inside to the outside. The heat storage body 4 is used to store heat in the oxidation chamber 7, and the heat insulation layer 10 can prevent heat loss. By arranging the heat storage body 4 between the oxidation chamber 7 and the heat insulation layer 10, the heat storage effect can be greatly improved, and there is no need to set up additional heat storage materials, which can greatly improve the compactness of the device.

[0034] 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, and 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 in the direction of the oxidation chamber 7 is an acute angle. Setting the axial angle between the through hole and the flame stabilizing disk 3 to an acute angle can ensure that the gas entering from the through hole can cross and collide, thereby decelerating the gas and ensuring that the gas is fully ignited in the oxidation chamber 7;

[0035] It should be noted that a gas outlet end coaxially arranged with the high-temperature flue gas outlet 9 is arranged at the center of the flame stabilizing disk 3, the inner diameter of the gas outlet end is larger than the inner diameter of the through hole, the through holes are arranged circumferentially of the gas outlet end, and the gas outlet end is in a closed state.

[0036] refer to Figure 1 As an implementation method, the total area of ​​the through holes is 1 to 1.8 times the cross-sectional area of ​​the high-temperature flue gas outlet 9.

[0037] refer to Figure 1In one embodiment, two or more DC jet nozzles 2 are provided, and the DC jet nozzles 2 are evenly arranged in the circumferential direction of the end of the oxidation chamber 7, and the DC jet nozzles 2 are spaced at the same distance from the center of the flame stabilizing disk 3. By providing a plurality of DC jet nozzles 2, oxidation stability and sufficient jet oxidation intensity can be ensured;

[0038] It should be noted that the jet angle and gas flow rate of the DC jet nozzle 2 can be adjusted, thereby changing the jet intensity to adjust the suction and reflux of the high-temperature flue gas in the oxidation chamber 7. A guide device that can change the gas injection direction can be set in the DC jet nozzle 2, thereby realizing the adjustment of the jet angle of the DC jet nozzle 2.

[0039] refer to Figure 1 The present invention also discloses a method for flameless oxidation of low-concentration gas by direct current jet, which uses the above-mentioned flameless oxidation device of low-concentration gas by direct current jet, and its main steps are:

[0040] The gas enters the oxidation chamber 7 through the auxiliary air inlet 11 and the flame stabilizing plate 3, and is ignited by the ignition system 5;

[0041] After the initial oxidation temperature monitoring system 6 detects that the temperature of the oxidation chamber 7 is higher than the preset value, gas is introduced from the main air inlet 1 and gas is sprayed into the oxidation chamber 7 through the direct current jet nozzle 2, and the gas is rapidly oxidized at high temperature;

[0042] The heat storage body 4 and the heat insulation layer 10 are used to store heat and reduce heat dissipation losses. The high-temperature flue gas is discharged through the high-temperature flue gas outlet 9 to provide a heat source for heat users.

[0043] To ensure safety, the initial oxidation temperature monitoring system 6 and the oxidation main body temperature monitoring system 8 are interlocked with the gas intake regulating device;

[0044] By injecting strong direct current jet from direct current jet nozzle 2 and sudden change of flow cross section (high temperature flue gas outlet 9), high temperature flue gas entrainment is realized, and gas is oxidized in a very short time. Oxidation chamber 7 is violently turbulent and has no obvious flame surface.

[0045] refer to Figure 1 In one embodiment, the ratio of the amount of gas entering the oxidation chamber 7 from the DC jet injection port to the amount of gas entering the oxidation chamber 7 from the flame stabilizing disk 3 is 1 to 6, which can ensure stable oxidation and sufficient jet oxidation intensity.

[0046] refer to Figure 1 As an implementation method, after the temperature of the oxidation chamber 7 is higher than 800° C., the gas is introduced from the main air inlet 1, which can ensure instantaneous oxidation of the gas, thereby reducing the risk of gas explosion and improving production safety.

[0047] Adaptive changes made according to actual needs are all within the protection scope of the present invention.

[0048] 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 are 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 direct current 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, a DC jet nozzle is opened on the oxidation chamber along the circumference of the flame stabilizing disk, and a through hole is arranged on the flame stabilizing disk, the DC jet nozzle is connected with a main air inlet, and the through hole is connected with an auxiliary air inlet, and the total area of ​​the through hole is larger than the cross-sectional area of ​​the high-temperature flue gas outlet.

2. The direct current jet low concentration gas flameless oxidation device according to claim 1 is characterized in that: The auxiliary air inlet and the main air inlet are both provided with flow control meters for controlling the gas flow.

3. The direct current jet low concentration gas flameless oxidation device according to claim 1 is 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, 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.

4. The direct current jet low concentration gas flameless oxidation device according to claim 1 is 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.

5. The direct current jet low concentration gas flameless oxidation device according to claim 1 is characterized in that: The through holes are arranged in two or more forms, the through holes are evenly distributed in the circumferential direction of the flame stabilizing disk, and the distances between two or more through holes and the center of the flame stabilizing disk are equal. 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 toward the oxidation chamber is an acute angle.

6. The direct current jet low concentration gas flameless oxidation device according to claim 1 is characterized in that: The total area of ​​the through holes is 1 to 1.8 times the cross-sectional area of ​​the high-temperature flue gas outlet.

7. The direct current jet low concentration gas flameless oxidation device according to claim 1 is characterized in that: The number of the DC jet nozzles is two or more, and the DC jet nozzles are evenly distributed in the circumferential direction of the end of the oxidation chamber, and the distances between the DC jet nozzles and the center of the flame stabilizing disk are equal.

8. A method for flameless oxidation of low-concentration gas by direct current jet, using the device for flameless oxidation of low-concentration gas by direct current jet according to any one of claims 1 to 7, characterized in that: The following steps are involved: The gas enters the oxidation chamber through the auxiliary air inlet and the flame stabilizing plate in sequence and is ignited by the ignition system; When the temperature of the oxidation chamber rises, air is taken in from the main air inlet and gas is sprayed into the oxidation chamber through the DC jet nozzle, so that the gas is rapidly oxidized at high temperature.

9. The method for flameless oxidation of low-concentration gas by direct current jet according to claim 8, characterized in that: The ratio of the amount of gas entering the oxidation chamber from the direct current jet injection port to the amount of gas entering the oxidation chamber from the flame stabilizing disk is 1 to 6.

10. The method for flameless oxidation of low-concentration gas by direct current jet according to claim 8, characterized in that: After the temperature of the oxidation chamber is higher than 800° C., air is introduced through the main air inlet.

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