Combustion device and exhaust gas treatment method

Abstract

The application discloses a combustion device and a waste gas treatment method. The combustion device comprises a first air feeding mechanism, a second air feeding mechanism, a first mixing mechanism, a second mixing mechanism, a combustion cavity, a combustion mechanism and a third air feeding mechanism. The air outlet of the first air feeding mechanism is communicated with the first mixing mechanism, and the first air feeding mechanism is used for feeding the first gas into the first mixing mechanism. The air outlet of the second air feeding mechanism is communicated with the combustion cavity, and the second air feeding mechanism is used for feeding the second gas into the combustion cavity. The combustion mechanism of the application solves the VOC waste gas treatment problem of low concentration, small flow, large component fluctuation and intermittent emission by treating different heat value waste gases respectively. The combustion device of the application further ensures that the waste gas can be safely and stably combusted under the condition of low heat value and small flow through the methods of strengthening mixing, surface premixed combustion and auxiliary combustion.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of petroleum chemical industry, in particular to a combustion device and a waste gas treatment method. BACKGROUND

[0002] The treatment technology of industrial VOCs mainly includes recovery technology and decomposition technology. The decomposition technology refers to the treatment of VOCs by thermal oxidation or thermal decomposition, such as direct combustion (TO method), catalytic combustion (CO method) or regenerative combustion (RTO method). However, these technologies also have obvious shortcomings. The TO furnace is generally suitable for high-concentration VOC waste gas treatment. When treating low-concentration VOC, more combustion-supporting fuel is needed, the energy consumption is large, waste heat recovery is needed, and the system is complex. Due to the slow start-up time, generally 1-2 hours are needed, it is suitable for continuous VOC emission treatment, but not suitable for intermittent emission. On the other hand, due to the local high temperature of the TO furnace, it is easy to cause NO x x emission. The RTO furnace is limited by the heating rate of the ceramic regenerator, and the equipment start-up time is slow, generally 2-4 hours are needed, and it is only suitable for continuous VOC emission treatment, not suitable for intermittent treatment. In addition, the RTO furnace has strict requirements on the concentration of VOC inlet gas, which must be lower than 25% of the lower explosive limit, and it is not suitable for VOC waste gas with large component fluctuations. The CO furnace needs to preheat the waste gas, generally uses electric heating or flue gas heating, and the equipment start-up time is also slow, generally 1-2 hours are needed, and it is only suitable for continuous VOC emission treatment, not suitable for intermittent treatment. In addition, like the RTO furnace, the CO furnace has strict requirements on the concentration and components of VOC inlet gas, which must be lower than 25% of the lower explosive limit, and the waste gas cannot contain components that can poison the catalyst. Long-term operation will produce solid waste pollutants.

[0003] The VOC waste gas discharged from the tank area in the field of petroleum chemical industry often has the following characteristics: low concentration (generally not more than 300 g / m 3 ), small flow (single waste gas generally not more than 2000 Nm 3 / h), intermittent emission, and large component fluctuations. The traditional incineration treatment technology such as CO furnace, TO furnace and RTO furnace has obvious shortcomings for this type of VOC waste gas. In the treatment of this field waste gas, the domestic method mainly uses condensation adsorption or oil recovery adsorption. Although this method is safe and feasible, it has the disadvantages of high equipment energy consumption, high operating cost, and low treatment rate of NMHC (non-methane hydrocarbon), which gradually cannot meet the environmental protection standards.

[0004] The above combustion methods have obvious problems in treating VOC waste gas with intermittent emission, large component fluctuation, low concentration and small flow. Even if the VOC waste gas with low concentration and small flow is treated, great energy consumption and equipment maintenance cost will be caused, and there are problems of complex equipment and extremely low economic benefit. SUMMARY

[0005] The present application aims to provide a combustion device and a waste gas treatment method. The combustion device of the present application solves the above technical problems by improving the structure and treating waste gas with different heat values.

[0006] Embodiments of the present application provide a combustion device, which comprises a first gas feeding mechanism, a second gas feeding mechanism, a first mixing mechanism, a second mixing mechanism, a combustion cavity, a combustion mechanism and a third gas feeding mechanism.

[0007] The gas outlet of the first gas feeding mechanism is communicated with the first mixing mechanism, and the first gas feeding mechanism is used for feeding the first gas into the first mixing mechanism.

[0008] The gas outlet of the second gas feeding mechanism is communicated with the combustion cavity, and the second gas feeding mechanism is used for feeding the second gas into the combustion cavity.

[0009] The gas outlet of the first mixing mechanism is communicated with the gas inlet of the second mixing mechanism, and the first mixing mechanism is used for feeding the mixed gas into the second mixing mechanism.

[0010] The gas outlet of the second mixing mechanism is communicated with the gas inlet of the combustion mechanism, and the second mixing mechanism is used for feeding the mixed gas into the combustion mechanism.

[0011] The combustion mechanism is located inside the combustion cavity, and is used for providing a combustion surface.

[0012] The gas outlet of the third gas feeding mechanism is communicated with the first mixing mechanism, and the third gas feeding mechanism is used for feeding the fuel gas into the first mixing mechanism.

[0013] In some embodiments, the first gas feeding mechanism comprises a first pipeline, a first jet mechanism and a second jet mechanism.

[0014] The first jet mechanism is arranged at the gas outlet end of the first pipeline, and the diameter of the first jet mechanism gradually decreases along the axial direction.

[0015] The second jet mechanism is arranged around the first pipeline, and is used for changing the first gas flowing along the axial direction into radial flow and feeding the first gas into the first mixing mechanism.

[0016] In some embodiments, the first jet mechanism is provided with first jet holes, and the first jet holes are arranged in a column.

[0017] Along the radial direction, the second injection mechanism is provided with second injection holes.

[0018] In some embodiments, along the radial direction, the spacing between the second injection holes gradually decreases.

[0019] In some embodiments, along the radial direction, the aperture of the second injection holes gradually increases.

[0020] In some embodiments, the second air feeding mechanism comprises a ring-shaped second pipeline and a third injection mechanism in communication with the second pipeline; the third injection mechanism comprises an air injection element in communication with the second pipeline and a first nozzle provided at the air outlet of the air injection element.

[0021] In some embodiments, the air injection port of the first nozzle is provided with an air injection end face, and the air injection end face is provided with third injection holes.

[0022] In some embodiments, the combustion mechanism has a frustum structure, and the diameter of the combustion mechanism gradually decreases along the direction of air flow.

[0023] In some embodiments, the angle between the air injection end face and the surface of the combustion mechanism is less than 90°.

[0024] In some embodiments, the first mixing mechanism comprises a first mixing cavity and a cyclone mechanism.

[0025] The first mixing cavity is sleeved on the outer periphery of the first pipeline.

[0026] The cyclone mechanism is provided at the air outlet of the first pipeline.

[0027] In some embodiments, the third air feeding mechanism comprises a third pipeline and a fourth injection mechanism provided at the air outlet of the third pipeline.

[0028] The third pipeline extends along the axial direction inside the first pipeline.

[0029] Along the axial direction, the first pipeline has a first end and a second end respectively, and the fourth injection mechanism is provided at the second end of the first pipeline.

[0030] In some embodiments, the cyclone mechanism comprises a plurality of cyclone blades extending along the circumferential direction.

[0031] In some embodiments, the cyclone angle of the cyclone blades is 30°-45°.

[0032] In some embodiments, the combustion device comprises a fourth air feeding mechanism for feeding combustion-supporting agents into the combustion cavity.

[0033] In some embodiments, the combustion device comprises an ignition mechanism for igniting the exhaust gas sent into the combustion chamber.

[0034] In some embodiments, the combustion device comprises a detection mechanism for detecting the flame combustion state.

[0035] Correspondingly, the application also provides an exhaust gas treatment method, which utilizes the above-mentioned combustion device to treat the exhaust gas, and comprises the following steps:

[0036] (a) the first gas with high heat value is sent into the combustion device for combustion through the first gas sending mechanism;

[0037] (b) the second gas with low heat value is sent into the combustion device for combustion through the second gas sending mechanism.

[0038] The combustion device provided by the application solves the problem of treating VOC exhaust gas with low concentration, small flow, large component fluctuation and intermittent emission by setting different gas sending mechanisms; the combustion device provided by the application further ensures that the exhaust gas can be safely and stably combusted under the condition of low heat value and small flow through the methods of strengthening mixing, surface premixed combustion and auxiliary combustion; the combustion device provided by the application improves the treatment rate of NMHC, and the emission of pollutants such as NOx and CO can also meet the environmental protection requirements of the state and the local government. BRIEF DESCRIPTION OF DRAWINGS

[0039] In order to more clearly illustrate the technical solutions in the embodiments of the application, the drawings needed in the embodiment description will be briefly introduced. Obviously, the drawings in the following description are only some embodiments of the application, and other drawings can also be obtained by those skilled in the art without creative labor on the basis of these drawings.

[0040] Figure 1 Fig. 1 is a structural schematic diagram of the combustion device according to the embodiment 1 of the application;

[0041] Figure 2 Fig. 2 is a sectional view of the combustion device according to the embodiment 1 of the application;

[0042] Figure 3 Fig. 3 is a top view of the first gas sending mechanism in the combustion device according to the embodiment 1 of the application; Figure 2 Fig. 4 is an enlarged structural schematic diagram of the A part in Fig. 3;

[0043] Figure 4 Fig. 5 is a structural schematic diagram of the first gas sending mechanism in the combustion device according to the embodiment 1 of the application;

[0044] Figure 5 Fig. 6 is a structural schematic diagram of the second gas sending mechanism in the combustion device according to the embodiment 1 of the application;

[0045] Figure 6Structure schematic view of the second air supply mechanism in Embodiment 1 of the present application;

[0046] Figure 7 Structure schematic view of the second air supply mechanism in Embodiment 1 of the present application; Figure 6 Structure schematic view of the B part of the second air supply mechanism in Embodiment 1 of the present application;

[0047] Figure 8 Top view of the cyclone mechanism and the third air supply mechanism in Embodiment 1 of the present application;

[0048] Figure 9 Structure schematic view of the cyclone mechanism and the third air supply mechanism in Embodiment 1 of the present application;

[0049] In the figure, 1 is the first air supply mechanism, 110 is the first end, 120 is the second end, 11 is the first pipeline, 111 is the first air inlet, 12 is the first injection mechanism, 121 is the first injection hole, 13 is the second injection mechanism, 131 is the second injection hole, 2 is the second air supply mechanism, 21 is the second pipeline, 22 is the third injection mechanism, 221 is the air injection element, 222 is the first nozzle, 223 is the air injection end face, 224 is the third injection hole, 3 is the first mixing mechanism, 31 is the mixing cavity, 32 is the cyclone mechanism, 321 is the cyclone blade, 4 is the second mixing mechanism, 5 is the combustion cavity, 51 is the flue gas outlet, 6 is the combustion mechanism, 7 is the third air supply mechanism, 71 is the third pipeline, 711 is the second air inlet, 72 is the fourth injection mechanism, 721 is the second nozzle, 8 is the fourth air supply mechanism, 9 is the ignition mechanism, 10 is the detection mechanism, 101 is the first flame detection device, 102 is the second flame detection device, and 103 is the electric thermocouple. DETAILED DESCRIPTION

[0050] The technical solutions in the embodiments of the present application will be clearly and completely described below with reference to the drawings in the embodiments of the present application. Obviously, the described embodiments are only some of the embodiments of the present application, rather than all the embodiments of the present application. Based on the embodiments in the present application, all other embodiments obtained by those skilled in the art without creative work fall within the scope of protection of the present application. In addition, in the description of the present application, the term “comprising” means “including but not limited to”. The terms first, second, third, etc. are only used for identification, and do not impose numerical requirements or establish sequences. The various embodiments of the present application can exist in a range type. It should be understood that the description in a range type is only for the convenience and brevity, and should not be understood as a hard limitation on the scope of the present application.

[0051] In order to better solve the VOC waste gas treatment problem of low concentration, small flow, large component fluctuation and intermittent discharge, the embodiments of the present application propose a combustion device, such as Figure 1 , Figure 2 and Figure 3As shown, the combustion device comprises a first gas feeding mechanism 1, a second gas feeding mechanism 2, a first mixing mechanism 3, a second mixing mechanism 4, a combustion chamber 5, a combustion mechanism 6 and a third gas feeding mechanism 7. Figure 2 In the embodiment, the direction in which the X axis extends is the axial direction, and is also the direction from the rear end to the front end described in the embodiment. The direction in which the Y axis extends is the radial direction, and is also the spanwise direction described in the embodiment.

[0052] In the embodiment, the gas outlet of the first gas feeding mechanism 1 is in communication with the first mixing mechanism 3, and is used to feed the first gas into the first mixing mechanism 3. The gas outlet of the third gas feeding mechanism 7 is in communication with the first mixing mechanism 3, and is used to feed the fuel gas into the first mixing mechanism 3. The gas outlet of the first mixing mechanism 3 is in communication with the gas inlet of the second mixing mechanism 4, and is used to feed the gas mixed in the first mixing mechanism 3 into the second mixing mechanism 4. The gas outlet of the second mixing mechanism 4 is in communication with the gas inlet of the combustion mechanism 6, and is used to feed the mixed gas into the combustion mechanism 6. The combustion mechanism 6 is located inside the combustion chamber 5, and is used to provide a combustion surface.

[0053] In the embodiment, the gas outlet of the second gas feeding mechanism 2 is in communication with the combustion chamber 5, and is used to feed the second gas into the combustion chamber 5. The second gas fed into the combustion chamber 5 is combusted on the surface of the combustion mechanism 6.

[0054] The first gas and the second gas in the embodiment can be the same or different. In a specific embodiment, the first gas and the second gas are different. As an optional embodiment, the concentration of the organic matter in the first gas ranges from 50 g / m 3 to 350 g / m 3 , and the concentration of the organic matter in the second gas is lower than 50 mg / m 3 .

[0055] In the application, different waste gases (the waste gases are divided into two paths according to the concentration, flow, components and other conditions of the waste gases: the main path waste gas, i.e., the first gas, and the branch path waste gas, i.e., the second gas) are mixed in advance and fed into the combustion device through the first gas feeding mechanism 1 and the second gas feeding mechanism 2. The different waste gases are fed into the combustion chamber 5 through different paths, which avoids the large fluctuation of the waste gas calorific value due to different sources of the waste gas, and avoids the large adjustment range and poor adjustment performance of the combustor due to the large fluctuation of the gas components. The waste gas fed through the first gas feeding mechanism 1 is strongly mixed through the first mixing mechanism 3 and the second mixing mechanism 4, which ensures that the waste gas can be safely and stably combusted under the condition of low calorific value and small flow, and the treatment rate of NMHC, the emission of pollutants such as NO x , CO and the like can also meet the environmental protection requirements.

[0056] In a specific embodiment, the fourth air feeding mechanism 8 is used to feed the combustion-supporting agent into the first mixing mechanism 3, i.e. the first air feeding mechanism 1 is used to feed the first gas into the first mixing mechanism 3, the third air feeding mechanism 7 is used to feed the fuel gas into the first mixing mechanism 3, the fourth air feeding mechanism 8 is used to feed the combustion-supporting agent into the first mixing mechanism 3, and the first mixing mechanism 3 mixes the first gas, the fuel gas and the combustion-supporting agent, and then feeds the mixed gas into the second mixing mechanism 4, and the gas mixed in the second mixing mechanism 4 is fed into the combustion mechanism 6 in the combustion chamber 5 for combustion.

[0057] In a specific embodiment, the fourth air feeding mechanism 8 is an air feeding pipe opening to the first mixing mechanism 3, which is in communication with a blower, and is used to feed air into the first mixing mechanism 3 as the combustion-supporting agent.

[0058] In a specific embodiment, the combustion device further comprises an ignition mechanism 9, which is used to ignite the exhaust gas fed into the combustion chamber 5.

[0059] In a specific embodiment, the combustion chamber 5 is composed of a combustion cylinder, and in a specific application, the height of the combustion cylinder is not less than 12 meters, and the height of the entire combustion device is not less than 15 meters.

[0060] In a specific embodiment, the combustion device further comprises a detection mechanism 10, which comprises a first flame detection device 101 arranged in the combustion chamber 5 and a second flame detection device 102 arranged in the first mixing mechanism 3, and can determine the flame state of the ignition gun as the ignition mechanism 9 and the burner as the combustion mechanism 6 at any time. Further, along the axial direction X, a plurality of thermocouples 103 are arranged at different positions of the combustion chamber 5, which are used to detect the flue gas temperature in the combustion cylinder. Since the VOC exhaust gas has a large fluctuation in concentration and composition, when the temperature rises or falls, the temperature detection signal of the thermocouple will be fed back to the blower and the control valve group of the fuel gas, so as to adjust the amount of fuel gas and the flow of combustion-supporting agent (air) to maintain the combustion cylinder temperature stable in the design range.

[0061] As Figure 4 and Figure 5As shown, the first gas feeding mechanism 1 of the present application comprises a first pipeline 11, a first injection mechanism 12 and a second injection mechanism 13. The first gas inlet 111 of the first pipeline 11 is the inlet of the first gas, the first pipeline 11 extends along the axial direction X and is located inside the first mixing mechanism 3 for feeding the first gas into the first mixing mechanism 3 for mixing. The first injection mechanism 12 is arranged at the gas outlet end of the first pipeline 11, the first injection mechanism 12 is used for feeding the first gas out of the first pipeline 11 and achieving the uniform distribution of the first gas in the first mixing mechanism 3. In order to achieve better mixing effect, the first injection mechanism 12 is a hollow conical structure, the diameter of the first injection mechanism 12 gradually decreases along the axial direction X, and the first injection hole 121 is arranged on the conical surface formed by the first injection mechanism 12. Through the design of the conical surface structure, the flow rate of the first gas fed out of the first injection hole 121 is improved, and the mixing effect is increased. The first injection hole 121 can be arranged in different ways, in order to achieve uniform mixing of the gas, the first injection hole 121 is arranged in a column on the conical surface formed by the first injection mechanism 12, the spacing between the first injection holes 121 is the same, and the diameter of the first injection hole 121 is the same, which ensures the uniform distribution of the gas flow space. In a specific embodiment, the diameter of the first injection hole 121 is 2mm-4mm.

[0062] In the present embodiment, the second injection mechanism 13 is arranged on the side wall of the pipeline at the gas outlet end of the first pipeline 11, the second injection mechanism 13 is arranged around the first pipeline 11, in a specific embodiment, the second injection mechanism 13 is a spray pipe in communication with the first pipeline 11, the outlet end of the spray pipe is closed, and the second injection mechanism 13 is used for changing the flow direction of the first gas flowing along the axial direction X to the radial direction Y, and feeding the first gas into the first mixing mechanism 3 through the second injection hole 131 arranged on the second injection mechanism 13. The second injection hole 131 is distributed along the radial direction Y on the second injection mechanism 13, and the spacing between the second injection holes 131 gradually decreases along the radial direction Y, the proportion of the decrease in the spacing between adjacent second injection holes 131 can decrease in the form of a geometric progression, and the diameter of the second injection hole 131 gradually increases, the proportion of the increase in the diameter of the second injection hole 131 can increase in the form of a geometric progression or an arithmetic progression, in a specific application, the diameter of the second injection hole 131 can be selected in the range of 2mm-4mm; through the design of the second injection hole 131 with gradually decreasing spacing and gradually increasing diameter, the exhaust gas can enter the first mixing mechanism 3 more uniformly through the second injection hole 131. In a specific embodiment, two rows of second injection holes 131 are arranged on each second injection mechanism 13, and the second injection holes 131 are arranged on the side of the second injection mechanism 13 away from the first gas inlet 111.

[0063] The first gas is directly sent into the first mixing mechanism 3 through the first injection mechanism 12, and is partially sent into the first mixing mechanism 3 through the second injection mechanism 13. The gas sent through the first injection mechanism 12 and the gas sent through the second injection mechanism 13 can be uniformly distributed in space due to different directions. The gas sent through the second injection mechanism 13 is mixed with the combustion-supporting agent in the planar area perpendicular to the axial direction in the channel of the first mixing mechanism 3, and is more uniformly mixed.

[0064] As shown in Figure 6 and Figure 7 , the second gas sending mechanism 2 in the embodiment includes a ring-shaped second pipeline 21 and a third injection mechanism 22 in communication with the second pipeline 21. The second gas sending mechanism 2 is arranged at the inlet end of the combustion chamber 5 to directly send the second gas into the combustion chamber 5. After the second gas is ignited by the ignition mechanism 9, the second gas is burned on the surface of the combustion mechanism 6.

[0065] The second pipeline 21 of the second gas sending mechanism 2 is a ring-shaped pipeline arranged around the inlet end of the combustion chamber 5. The second pipeline 21 is connected with a plurality of third injection mechanisms 22. The third injection mechanisms 22 extend along the axial direction X to divide the second gas into a plurality of branches to be sent into the combustion chamber 5. In a specific embodiment, the number of the third injection mechanisms 22 is selected to be even, and the third injection mechanisms 22 are symmetrically arranged in the circumferential direction.

[0066] The third injection mechanism 22 includes a gas injection element 221 in communication with the second pipeline 21 and a first nozzle 222 arranged at the gas outlet of the gas injection element 221. The gas injection port of the first nozzle 222 is provided with a gas injection end face 223. The third injection holes 224 are arranged on the gas injection end face 223 and can be uniformly and spacedly distributed on the gas injection end face 223. In the embodiment, the gas injection element 221 can be a nozzle in communication with the second pipeline 21, and the first nozzle 222 is arranged at the gas outlet end of the nozzle. In a specific embodiment, the diameter of the third injection holes 224 is 2mm-4mm.

[0067] The first mixing mechanism 3 includes a mixing chamber 31 and a cyclone mechanism 32. The mixing chamber 31 is a cavity arranged on the outer periphery of the first pipeline 11 to provide a gas mixing cavity. Figure 8As shown, in this embodiment, the gas mixing effect is further improved by the arrangement of the swirling mechanism 32. Specifically, the first pipe 11 has a first end 110 and a second end 120 along the axial direction X. A swirling mechanism 32 is arranged at the second end 120 of the first pipe 11. The swirling mechanism 32 includes a plurality of swirling blades 321. The plane in which the plurality of swirling blades 321 are located is parallel to the radial section (YZ axis plane) of the combustion device. The swirling blades 321 can be helical blades. In some specific embodiments, the swirling angle of the swirling blades 321 is 30° to 45°, which further improves the mixing effect of the airflow passing through the swirling blades. In a specific application example, the diameter of the swirling blades 321 is 2 / 3 times the outer cylinder diameter of the first mixing mechanism 3.

[0068] In this embodiment, the first injection mechanism 12 with a conical structure, several second injection mechanisms 13 surrounding the first pipeline 11, and the swirling mechanism 32 set at the front end of the first pipeline 11 increase the swirling intensity of the first gas and the combustion-supporting gas, so that the first gas and the combustion-supporting gas are fully mixed with the fuel gas sent from the second nozzle 721.

[0069] like Figure 9 As shown, in this embodiment, fuel gas is supplied through a third gas supply mechanism 7. The third gas supply mechanism 7 includes a third pipeline 71 and a fourth injection mechanism 72 disposed at the outlet of the third pipeline 71. The fuel gas is supplied into the third pipeline 71 through the second inlet 711. Since the supplied fuel gas is relatively small, in order to ensure that it is fully mixed with the first gas and the combustion improver, in this embodiment, the third pipeline 71 is disposed inside the first pipeline 11. The third pipeline 71 extends along the axial direction X inside the first pipeline 11. As an optional implementation, the third pipeline 71 and the first pipeline 11 are arranged in a concentric circle manner in the axial central axis O1 direction of the combustion device. The fourth injection mechanism 72 is a fuel gas delivery mechanism. The fourth injection mechanism 72 is located at the second end 120 of the first pipeline 11 and at the front end of the swirl mechanism 32. The fourth injection mechanism 72 includes a second nozzle 721 for fuel gas delivery. The second nozzle 721 is provided with a plurality of nozzle holes. In a specific application embodiment, the nozzle diameter of the fuel gas is 1mm to 1.5mm.

[0070] In this embodiment, the outlet of the third gas delivery mechanism 7 is located at the front end of the first injection mechanism 12, the second injection mechanism 13, and the swirl mechanism 32. This ensures that the small flow rate of fuel gas delivered through the second nozzle 721 is rotated by the large flow rate of combustion-supporting gas that has passed through the swirl mechanism 32 beforehand, thus ensuring the mixing effect between the two. At the same time, the third gas delivery mechanism 7, configured in this way, does not affect the gas mixing effect, and the improvement of the structure of the three components increases the gas mixing effect.

[0071] In the embodiment, the second mixing mechanism 4 is a Venturi structure arranged at the gas outlet end of the first mixing mechanism 3, and the minimum flow rate of the gas distributor below the metal fiber mesh of the combustion mechanism 6 at the throat position of the Venturi structure is designed to be greater than the corresponding premixed gas flame burning speed, which can further avoid the occurrence of backfire.

[0072] The gas outlet of the second mixing mechanism 4 is in communication with the combustion chamber 5, the combustion chamber 5 has a flue gas outlet 51, and the combustion mechanism 6 is arranged at the inlet of the combustion chamber 5.

[0073] In the embodiment, the combustion mechanism 6 is arranged at the bottom. In order to avoid the influence of the gas flow flowing out of the rear end of the combustion mechanism 6 on the gas flow flowing out of the front end of the combustion mechanism 6, the combustion mechanism 6 has a hollow circular truncated cone structure as a whole, and the diameter gradually decreases along the direction extending along the axial direction X, which further reduces the interference between the upper and lower flames.

[0074] As shown in Figure 7 In order to avoid that the low-calorific-value waste gas sent by the second gas sending mechanism 2 cannot be stably combusted on the surface of the combustion mechanism 6, in the embodiment, the included angle between the jet end face 223 and the surface of the combustion mechanism 6 is less than 90°, so that the low-calorific-value waste gas is sprayed out of the plurality of jet holes of the third jet hole 224 and uniformly contacts the surface burner flame surface or reaches the vicinity of the surface burner flame surface in the axial direction, which ensures that the low-calorific-value gas is fully combusted but the flame is not easily blown out.

[0075] In the embodiment, the combustion mechanism 6 adopts a surface burner, the main path waste gas, fuel gas and combustion-supporting air are uniformly mixed by the first mixing mechanism 3 and the second mixing mechanism 4, and then reach the metal fiber surface of the surface burner, at this time, ignition is performed by the ignition gun beside the surface burner to realize the combustion of the main flame of the burner. Because there are millions of micro-pore structures on the metal fiber surface, the main flame of the burner is stably maintained on the metal fiber mesh surface and is not easy to backfire.

[0076] In the embodiment, in order to further ensure the stable combustion of the flame when the waste gas intermittently fluctuates, the ignition mechanism 9 (which is selected as an ignition gun in specific applications) is designed to have a permanent light function, when the concentration of organic matter in the waste gas sent by the second gas sending mechanism 2 is too low to sustain combustion, the ignition mechanism 9 is used to maintain the stable combustion of the flame.

[0077] In specific applications, the waste gas treatment capacity of the combustion device ranges from 300 Nm 3 / h to 3000 Nm 3 / h, the maximum flow rate of the fuel gas sent by the third gas sending mechanism 7 is 30 Nm 3 / h, and the concentration of organic matter in the main path waste gas ranges from 50 g / m 3 to 350 g / m 3 . If the concentration of organic matter is selected to be 100 g / m 3 to 300 g / m3 The exhaust gas; the organic matter concentration in the branch exhaust gas ranges from 50mg / m 3 Hereinafter, the air flow rate range sent by the fourth air sending mechanism 8 is 10m / s~15m / s, the maximum flow rate range of the injection holes of the first injection mechanism 12 and the second injection mechanism 13 is 120~150m / s, and the maximum flow rate of the injection holes of the fourth injection mechanism 72 is 150m / s~200m / s. The minimum flow rate at the Venturi throat of the second mixing mechanism 4 is not less than 10m / s.

[0078] The flue gas temperature in the combustion chamber 5 is controlled at 1000-1200℃, the oxygen concentration at the outlet of the combustion chamber 5 is controlled at about 10%, the flue gas residence time is not less than 1s, and the outer wall temperature of the combustion cylinder is not less than 90℃.

[0079] The combustion device of the present application is suitable for the treatment of VOC exhaust gas with small flow rate, low concentration and large fluctuation, and intermittent discharge in the chemical tank area. The combustion device ensures that the exhaust gas can be safely and stably combusted under the condition of low heat value and small flow rate through surface premixed combustion and auxiliary combustion, and the treatment rate of NMHC, NOx, CO and other pollutants can also meet the environmental protection requirements of the state and the local.

[0080] The working principle of the combustion device of the present application is as follows:

[0081] According to the conditions such as concentration, flow rate and components, the multiple exhaust gases are divided into two routes: main route exhaust gas (first gas) and branch route exhaust gas (second gas). Each route of exhaust gas is composed of several exhaust gases, which are mixed in advance and then enter the combustion cylinder for combustion. The main route exhaust gas and the fuel gas and the combustion supporting air are mixed by pipeline arrangement and injection hole structure, and then mixed again by the cyclone blade and the Venturi, so as to fully ensure that the fuel gas, the exhaust gas and the air are fully mixed when reaching the burner. The branch route exhaust gas is uniformly distributed through the annular pipe formed by the second pipeline 21, and then sprayed into the combustion cylinder through the multiple third injection mechanisms 22 near the burner at the bottom of the combustion cylinder to contact and combust with the high-temperature flue gas.

[0082] The exhaust gas treatment method using the combustion device of the present application is as follows:

[0083] (a) The first pipeline 11 sends the main route exhaust gas, the third pipeline 71 sends the fuel gas, and the fourth air sending mechanism 8 sends the combustion supporting air. After the main route exhaust gas and the fuel gas enter the first air inlet 111 and the second air inlet 711 respectively, the main route exhaust gas is sent out through the first injection mechanism 12 and the second injection mechanism 13 arranged on the first pipeline 11, mixed with the air sent by the fourth air sending mechanism 8, and preliminarily mixed after passing through the cyclone blade 321. The fuel gas is sprayed into the exhaust gas and the air through the fourth injection mechanism 72 at the front end of the cyclone blade 321, and forms the final fuel premixed gas.

[0084] (b) The fuel premixed gas enters the second mixing mechanism 4 and is further mixed in the venturi mixing chamber.

[0085] (c) The mixed fuel premixed gas enters the combustion mechanism 6 and is ignited by the ignition mechanism 9, and a stable flame is formed on the surface of the metal fiber of the combustion mechanism 6, and the high-temperature flue gas generated is discharged to the flue gas outlet 51 through the combustion cylinder; the first flame detection device 101 and the second flame detection device 102 monitor the flame condition of the entire combustion process; after the ignition mechanism 9 ignites the burner, it acts as a long-lasting lamp and always maintains a burning state.

[0086] (d) The second gas supply mechanism 2 sends the branch exhaust gas into the combustion chamber 5, and the branch exhaust gas is uniformly distributed to each jet element 221 through the third jet mechanism 22 after passing through the second pipeline 21, and is directly sprayed into the combustion cylinder through the first nozzle 222.

[0087] (e) The hot spot couple 103 arranged in the height direction of the combustion cylinder can feedback the flue gas temperature in real time, and when the temperature deviates from the design range, the air intake amount of the fuel gas sent by the second air inlet 711 and the air intake amount of the air sent by the fourth gas supply mechanism 8 are adjusted to adjust the temperature.

[0088] (f) When the main road VOC exhaust gas pressure does not reach the set minimum value, the third pipeline 71 for sending fuel gas is cut off at this time, the fan is adjusted to the lowest opening, and the flame of the ignition mechanism 9 remains stable and unchanged.

[0089] (g) When the main road VOC exhaust gas pressure reaches the set minimum value, the combustion mechanism 6 starts, the air amount changes with the main road VOC exhaust gas flow, and the fuel gas amount is adjusted according to the temperature feedback of the thermocouple. As long as the ignition mechanism 9 is put into use, the branch VOC exhaust gas can be sent into the combustion chamber at any time.

[0090] In the above embodiments, the description of each embodiment has its own emphasis, and the parts not described in detail in a certain embodiment can be referred to the related description of other embodiments.

[0091] The above describes in detail a kind of combustion device and exhaust gas treatment method provided by the embodiment of the present application, specific examples are applied in this paper to describe the principle and implementation mode of the present application, the above embodiment is only used to help understand the method and its core idea of the present application;At the same time, for the person skilled in the art, according to the idea of the present application, there will be changes in specific implementation mode and application range, and the above description should not be understood as the limitation of the present application.

Claims

1. A combustion device, characterized in that, It includes a first air supply mechanism (1), a second air supply mechanism (2), a first mixing mechanism (3), a second mixing mechanism (4), a combustion chamber (5), a combustion mechanism (6), and a third air supply mechanism (7); The outlet of the first gas supply mechanism (1) is connected to the first mixing mechanism (3) for supplying the first gas to the first mixing mechanism (3); The outlet of the second gas supply mechanism (2) is connected to the combustion chamber (5) and is used to supply a second gas into the combustion chamber (5); The outlet of the first mixing mechanism (3) is connected to the inlet of the second mixing mechanism (4) to send the mixed gas into the second mixing mechanism (4); The outlet of the second mixing mechanism (4) is connected to the inlet of the combustion mechanism (6) to send the mixed gas into the combustion mechanism (6); The combustion mechanism (6) is located inside the combustion chamber (5) and is used to provide a combustion surface; The outlet of the third gas delivery mechanism (7) is connected to the first mixing mechanism (3) and is used to deliver fuel gas into the first mixing mechanism (3); The first air delivery mechanism (1) includes a first pipeline (11), a first injection mechanism (12), and a second injection mechanism (13); The first injection mechanism (12) is located at the air outlet of the first pipeline (11), and the diameter of the first injection mechanism (12) gradually decreases along the axial (X) direction; The second injection mechanism (13) is arranged around the first pipeline (11) for converting the first gas flowing along the axial direction (X) into radial (Y) flow and then feeding it into the first mixing mechanism (3).

2. The combustion device according to claim 1, characterized in that, The first spraying mechanism (12) is provided with a first spray hole (121), and the first spray hole (121) is arranged in a row; Along the radial direction (Y), the second spray mechanism (13) is provided with a second spray hole (131).

3. The combustion device according to claim 2, characterized in that, Along the radial direction (Y), the spacing between the second nozzles (131) gradually decreases; and / or, Along the radial direction (Y), the diameter of the second nozzle (131) gradually increases.

4. The combustion device according to claim 1, characterized in that, The second air delivery mechanism (2) includes an annular second pipe (21) and a third injection mechanism (22) connected to the second pipe (21); the third injection mechanism (22) includes an air jet element (221) connected to the second pipe (21) and a first nozzle (222) disposed at the air outlet of the air jet element (221).

5. The combustion device according to claim 4, characterized in that, The first nozzle (222) has an air jet outlet with an air jet end face (223), and a third nozzle hole (224) is provided on the air jet end face (223).

6. The combustion device according to claim 5, characterized in that, The combustion mechanism (6) has a frustum structure, and the diameter of the combustion mechanism (6) gradually decreases along the airflow direction.

7. The combustion device according to claim 6, characterized in that, The angle between the jet end face (223) and the surface of the combustion mechanism (6) is less than 90°.

8. The combustion device according to claim 6, characterized in that, The first mixing mechanism (3) includes a first mixing chamber (31) and a swirling mechanism (32); The first mixing chamber (31) is sleeved on the outer periphery of the first pipeline (11); The swirling mechanism (32) is located at the outlet end of the first pipeline (11).

9. The combustion device according to claim 4, characterized in that, The third air delivery mechanism (7) includes a third pipeline (71) and a fourth injection mechanism (72) disposed at the air outlet of the third pipeline (71); The third conduit (71) extends along the axial direction (X) inside the first conduit (11); Along the axial direction (X), the first pipe (11) has a first end (110) and a second end (120), and the fourth injection mechanism (72) is disposed at the second end (120) of the first pipe (11).

10. The combustion device according to claim 8, characterized in that, The swirling mechanism (32) includes a plurality of swirling blades (321) extending circumferentially; and / or, The swirl angle of the swirl blade (321) is 30° to 45°.

11. The combustion device according to claim 1, characterized in that, Includes a fourth gas delivery mechanism (8) for delivering combustion-supporting agent into the combustion chamber (5); and / or, Includes an ignition mechanism (9) for igniting the exhaust gas fed into the combustion chamber (5); and / or, It includes a detection mechanism (10) for detecting the state of flame combustion.

12. A method for treating exhaust gas using the combustion apparatus according to any one of claims 1 to 11, characterized in that, Includes the following steps: (a) The first gas is fed into the combustion device through the first gas supply mechanism (1) for combustion; (b) The second gas is fed into the combustion device for combustion through the second gas supply mechanism (2).

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