Waste gas mixing device and combustion system

Abstract

The utility model relates to the technical field of semiconductor manufacturing, and provides a waste gas mixing device and a combustion system, the waste gas mixing device comprises a mixing unit and a fuel supply unit; the fuel supply unit comprises a fuel supply pipeline; the mixing unit is provided with a mixing cavity, and the mixing unit is provided with a first air inlet, a second air inlet and an air outlet which are communicated with the mixing cavity; the first gas inlet is used for being connected with a waste gas source, the second gas inlet is connected with a fuel supply pipeline, and the gas outlet is used for being connected with a gas inlet of a combustion furnace. According to the waste gas mixing device, the fuel is mixed into the waste gas, then the waste gas is introduced into the hearth, on one hand, frequent starting and stopping of a combustor are not needed, generation of nitric oxide is reduced, and on the other hand, it is guaranteed that the fuel and the waste gas are evenly mixed, the combustion efficiency is improved, and the content of harmful substances in exhausted gas after combustion is reduced.

Description

Technical Field

[0001] The utility model relates to the technical field of semiconductor manufacturing, and particularly relates to an exhaust gas mixing device and a combustion system. Background Art

[0002] A direct combustion furnace (Thermal Oxidizer, TO) is a waste gas treatment device used to treat waste gas containing volatile organic compounds (VOCs) and harmful air pollutants (HAPs). Through high-temperature oxidation, harmful substances are converted into harmless substances for emission. Generally, the waste gas treatment temperature is set according to the ignition point (700°C - 900°C) of the treated gas components, and the waste gas stays in the furnace for 0.7 - 1.5 seconds for exothermic reaction treatment.

[0003] In industries such as chemical engineering and medicine, the waste gas generated has the characteristics of low air volume and high concentration, and the direct combustion furnace can be used alone. For the semiconductor industry, the waste gas generated has the characteristics of large air volume and low concentration. Therefore, the waste gas needs to be pretreated and concentrated first to meet the combustion conditions of the direct combustion furnace.

[0004] In domestic existing direct combustion furnaces, when the concentration of organic compounds in the introduced waste gas is low, the heat value released by the thermal decomposition of organic compounds is difficult to maintain the furnace temperature. The reduction of the furnace temperature will affect the decomposition of organic compounds. Therefore, heat compensation for the furnace is often required to ensure that the furnace temperature is within the normal range and the entire combustion furnace operates normally.

[0005] The existing heat compensation method usually directly introduces fuel (such as gas, fuel oil, etc.) into the furnace. The fuel inlet and the waste gas inlet are independent of each other. The waste gas in the furnace is always in a state of thermal decomposition. When the furnace temperature is low, fuel is introduced and ignited by a burner to ensure full combustion of the fuel.

[0006] The above compensation method requires frequent start-stop of the burner, resulting in a shortened service life of the burner. Moreover, when the burner ignites the fuel, a deflagration phenomenon will occur, and the formed hot flame will generate nitrogen oxides, causing secondary pollution. In addition, the introduced fuel and waste gas are difficult to be evenly mixed, and the contact between the waste gas and the fuel is not sufficient, resulting in incomplete combustion and a high content of harmful substances in the combustion exhaust gas, and low combustion efficiency of the combustion furnace. Summary of the Utility Model

[0007] The purpose of the utility model is to provide an exhaust gas mixing device and a combustion system. The exhaust gas mixing device mixes fuel into the exhaust gas and then introduces it into the furnace. On the one hand, it does not require frequent start-stop of the burner, reducing the generation of nitrogen oxides. On the other hand, it ensures uniform mixing of the fuel and the exhaust gas, improves combustion efficiency, and reduces the content of harmful substances in the combustion exhaust gas.

[0008] The present utility model provides an exhaust gas mixing device, comprising: a mixing unit and a fuel supply unit;

[0009] The fuel supply unit includes a fuel supply pipeline;

[0010] The mixing unit has a mixing chamber, and the mixing unit is provided with a first air inlet, a second air inlet and an air outlet that communicate with the mixing chamber;

[0011] The first air inlet is used to connect to an exhaust gas source, the second air inlet is connected to the fuel supply pipeline, and the air outlet is used to connect to the air inlet of a combustion furnace.

[0012] Optionally, the exhaust gas mixing device further includes a spray head connected to the fuel supply pipeline. A part of the spray head penetrates through the second air inlet into the mixing chamber, and spray holes communicating with the fuel supply pipeline are provided in the part of the spray head located in the mixing chamber.

[0013] Optionally, the opening directions of the first air inlet and the air outlet are the same and are oppositely arranged; and / or, the opening direction of the spray holes is perpendicular to the opening direction of the first air inlet.

[0014] Optionally, the fuel supply unit further includes a pressure stabilizing component, which is arranged on the fuel supply pipeline to regulate the air pressure in the fuel supply pipeline; and / or, the fuel supply unit further includes a leakage detection component, which is arranged on the fuel supply pipeline to detect gas leakage; and / or, the fuel supply unit further includes a flow regulating component, which is arranged on the fuel supply pipeline to regulate the gas flow in the fuel supply pipeline.

[0015] Optionally, when the fuel supply unit includes a pressure stabilizing component;

[0016] The pressure stabilizing component includes a pressure stabilizing valve arranged on the fuel supply pipeline;

[0017] and / or;

[0018] The pressure stabilizing component includes a high-pressure switch and a low-pressure switch arranged on the fuel supply pipeline.

[0019] Optionally, when the fuel supply unit includes a leakage detection component, the leakage detection component includes a pressure detection member, a first cut-off valve and a second cut-off valve arranged on the fuel supply pipeline, and the pressure detection member is located between the first cut-off valve and the second cut-off valve.

[0020] Optionally, when the fuel supply unit includes a flow regulating component, the flow regulating component includes a flow regulating valve arranged on the fuel supply pipeline.

[0021] The present utility model further provides a combustion system, which includes the waste gas mixing device described above, a waste gas source and a combustion furnace; an air outlet end of the waste gas source is connected to the first air inlet, and an air inlet of the combustion furnace is connected to the air outlet.

[0022] Optionally, the combustion system further includes a heat exchanger. An exhaust port of the combustion furnace is communicated with a hot path inlet of the heat exchanger. A cold path inlet of the heat exchanger is used for introducing combustion-supporting air, and a cold path outlet of the heat exchanger is communicated with an air-assisted gas port of the combustion furnace.

[0023] Optionally, the combustion system further includes a gas concentration detector, which is arranged on a path between the air outlet and the air inlet of the combustion furnace.

[0024] With such a configuration, the waste gas mixing device can mix fuel into low-concentration organic waste gas, increase the calorific value of the low-concentration waste gas, and enable the two to be fully mixed in the mixing chamber to form a mixed gas, and then the mixed gas is fed into the combustion furnace through the air outlet. The mixed gas burns in the combustion furnace to maintain the furnace temperature within a suitable range, which can ensure the continuous operation of the entire combustion system and avoid shutdown caused by too low furnace temperature due to insufficient calorific value of waste gas combustion.

[0025] The setting of this waste gas mixing device mixes fuel into the waste gas and then feeds it into the furnace. On the one hand, it can balance the inlet concentration, make the combustion in the combustion furnace stable, the calorific value in the furnace can continuously maintain combustion, reduce the start-stop frequency of the burner, extend the service life of the burner, and reduce nitrogen oxides generated by deflagration when the burner ignites fuel, reducing secondary pollution; on the other hand, the setting of the mixing unit enables the high-concentration fuel and ultra-low-concentration organic waste gas to be fully mixed, the combustion is more sufficient and stable, the combustion efficiency is improved, and the content of harmful substances in the exhaust gas after combustion is reduced. Description of the Drawings

[0026] Figure 1 is a schematic structural diagram of a combustion system according to an embodiment of the present utility model;

[0027] Figure 2 is a schematic structural diagram of a mixing unit according to an embodiment of the present utility model Figure 1 ;

[0028] Figure 3 is a schematic structural diagram of a mixing unit according to an embodiment of the present utility model Figure 2 ;

[0029] Figure 4 is a schematic structural diagram of a mixing unit according to another embodiment of the present utility model Figure 1 ;

[0030] Figure 5 Structural schematic of the blending unit according to another embodiment of the present utility model Figure 2 ;

[0031] Figure 6 Structural schematic of the blending unit according to another embodiment of the present utility model Figure 1 ;

[0032] Figure 7 Structural schematic of the blending unit according to another embodiment of the present utility model Figure 2 。

[0033] Among them, in the drawings:

[0034] 100 - Exhaust gas blending device;

[0035] 10 - Blending unit; 11 - Blending chamber; 12 - First air inlet; 13 - Second air inlet; 14 - Air outlet;

[0036] 20 - Fuel supply unit;

[0037] 21 - Fuel supply pipeline;

[0038] 22 - Voltage stabilizing component; 221 - Voltage stabilizing valve; 222 - High - voltage switch; 223 - Low - voltage switch;

[0039] 23 - Leakage detection component; 231 - Pressure detection part; 232 - First cut - off valve; 233 - Second cut - off valve;

[0040] 24 - Flow rate regulating component; 241 - Flow rate regulating valve;

[0041] 25 - Main fuel supply pipe;

[0042] 26 - Main valve;

[0043] 27 - Filter;

[0044] 28 - Pressure fine - tuning valve;

[0045] 291 - First pressure gauge; 292 - Second pressure gauge;

[0046] 30 - Sprinkler head; 31 - Spray hole;

[0047] 200 - Exhaust gas source;

[0048] 300 - Combustion furnace; 301 - Air auxiliary combustion air inlet; 302 - Gas emergency combustion air inlet;

[0049] 400 - Heat exchanger; 401 - Hot - path inlet; 402 - Hot - path outlet; 403 - Cold - path inlet; 404 - Cold - path outlet;

[0050] 500 - Tail gas emission device;

[0051] 600 - Flame arrester;

[0052] 700 - Gas concentration detector;

[0053] 800 - Shut-off valve. Detailed implementation manner

[0054] The following further describes in detail the waste gas mixing device and combustion system proposed by the present utility model in conjunction with the accompanying drawings and specific embodiments. According to the following description, the advantages and features of the present utility model will be clearer. It should be noted that the accompanying drawings are all in a very simplified form and use non-precise scales, only for the purpose of conveniently and clearly assisting in explaining the purpose of the embodiments of the present utility model.

[0055] As used in the present utility model, the singular forms "a", "an" and "the" include plural objects, the term "or" is usually used in the sense of including "and / or", the term "several" is usually used in the sense of including "at least one", the term "at least two" or "multiple" is usually used in the sense of including "two or more", in addition, the terms "first", "second", "third" are only used for descriptive purposes and cannot be understood as indicating or implying relative importance or implicitly indicating the quantity of the indicated technical features. Thus, the features defined with "first", "second", "third" may explicitly or implicitly include one or at least two of such features. In addition, as used in the present utility model, "installed", "connected", "coupled", an element "disposed" on another element should be understood in a broad sense, usually only indicating that there is a connection, coupling, cooperation or transmission relationship between the two elements, and the two elements can be directly or indirectly connected, coupled, cooperated or transmitted through an intermediate element, and cannot be understood as indicating or implying the spatial position relationship between the two elements, that is, an element can be inside, outside, above, below or on one side of another element, etc. in any orientation, unless the content clearly indicates otherwise. For those of ordinary skill in the art, the specific meanings of the above terms in the present utility model can be understood according to specific circumstances. In addition, directional terms such as above, below, up, down, upward, downward, left, right, etc. are used relative to the exemplary embodiments as shown in the figures, and the upward or upper direction faces the top of the corresponding figure, and the downward or lower direction faces the bottom of the corresponding figure.

[0056] The heat compensation method of the existing combustion furnace is usually to directly introduce fuel (such as gas, fuel oil, etc.) into the furnace. The fuel inlet and the waste gas inlet are independent of each other. The waste gas in the furnace is always in a thermal decomposition state. When the furnace temperature is low, fuel is introduced and the fuel is ignited by a burner to ensure full combustion of the fuel.

[0057] The above compensation method requires frequent start-stop operations of the burner, which shortens the service life of the burner. Moreover, when the burner ignites the fuel, deflagration will occur, and the resulting hot flame will generate nitrogen oxides, causing secondary pollution. In addition, the fuel and waste gas introduced are difficult to mix evenly, and the contact between the waste gas and the fuel is not sufficient, resulting in incomplete combustion. The content of harmful substances in the exhaust gas after combustion is high, and the combustion efficiency of the furnace is low. Furthermore, when introducing fuel, combustion-supporting air needs to be supplemented. The existing combustion furnace is provided with an air inlet for introducing combustion-supporting air. When this part of the air enters the furnace chamber, part of the fuel needs to be consumed for preheating, which also increases the operating cost.

[0058] Based on the above technical problems, a combustion system is provided in this embodiment.

[0059] Please refer to Figure 1 As shown, the combustion system includes an exhaust gas mixing device 100, an exhaust gas source 200, and a combustion furnace 300.

[0060] The exhaust gas mixing device 100 includes a mixing unit 10 and a fuel supply unit 20;

[0061] The fuel supply unit 20 includes a fuel supply pipeline 21;

[0062] Combined with Figure 2 As shown, the mixing unit 10 has a cylindrical structure. The mixing unit 10 has a mixing chamber 11, and the mixing unit 10 is provided with a first air inlet 12, a second air inlet 13, and an air outlet 14 that communicate with the mixing chamber 11.

[0063] The outlet end of the exhaust gas source 200 is connected to the first air inlet 12. The exhaust gas source 200 is a collection of organic exhaust gas generated during the semiconductor production process, and it introduces low-concentration exhaust gas into the mixing chamber 11 through the first air inlet 12.

[0064] The second air inlet 13 is connected to the fuel supply pipeline 21. The fuel supply pipeline 21 can be externally connected to a municipal fuel supply main pipe 25, such as externally connected to a natural gas supply main pipe, for introducing combustion-supporting fuel into the mixing chamber 11 through the second air inlet 13.

[0065] The air outlet 14 is connected to the air inlet of the combustion furnace 300 to introduce the mixed gas in the mixing unit 10 into the combustion furnace 300. In this embodiment, the combustion furnace 300 has a furnace chamber, and a burner is internally provided to ignite the mixed gas. The overall combustion furnace 300 can be set in the shape of a cuboid, a cylinder, or other shapes. The combustion furnace 300 can be consistent with the existing structure. The structure and working principle of the combustion furnace 300 both belong to the prior art and will not be elaborated here.

[0066] The waste gas mixing device can mix fuel into low-concentration organic waste gas, increase the calorific value of the low-concentration waste gas, and enable the two to be fully mixed in the mixing chamber 11 to form a mixed gas, which is then supplied into the combustion furnace 300 through the air outlet 14. The mixed gas burns in the combustion furnace 300 to maintain the furnace temperature within a suitable range, ensuring the continuous operation of the entire combustion system and avoiding shutdown caused by too low furnace temperature due to insufficient calorific value of waste gas combustion.

[0067] With the setting of this waste gas mixing device, fuel is mixed into the waste gas and then introduced into the furnace. On the one hand, it can balance the inlet gas concentration, make the combustion in the combustion furnace stable, continuously maintain combustion with the calorific value in the furnace, reduce the start-stop frequency of the burner, extend the service life of the burner, and reduce nitrogen oxides generated by deflagration when the burner ignites fuel, reducing secondary pollution; on the other hand, the setting of the mixing unit 10 enables the high-concentration fuel and the ultra-low-concentration organic waste gas to be fully mixed, making the combustion more sufficient and stable, improving the combustion efficiency, and reducing the content of harmful substances in the exhaust gas after combustion.

[0068] Please refer to Figure 2 As shown, in this embodiment, the mixing unit 10 is in a cylindrical structure. The first air inlet 12 and the second air inlet 13 are respectively arranged at the opposite ends of the mixing unit 10, and the first air inlet 12 and the second air inlet 13 are arranged opposite to each other along the axial direction. Therefore, the waste gas introduced through the first air inlet 12 will flow axially towards the second air inlet 13. Flanges are provided on both the first air inlet 12 and the second air inlet 13 to facilitate connection with other pipelines.

[0069] Furthermore, in this embodiment, the second air inlet 13 is opened along the radial direction of the mixing unit 10, and the second air inlet 13 is approximately located at the middle position of the mixing unit 10 along the axial direction. The waste gas mixing device 100 further includes a spray head 30. The spray head 30 is in a tubular structure and extends along the radial direction of the mixing unit 10. A part of the spray head 30 penetrates through the second air inlet 13 and is sealed into the mixing chamber 11. The spray head 30 can be welded to the mixing unit 10 to ensure no leakage in welding. One end of the spray head 30 located in the mixing chamber 11 is sealed, and spray holes 31 are provided on the outer periphery of the part of the spray head 30 located in the mixing chamber 11. The diameter of the spray holes 31 is as small as possible, aiming to make the velocity of the combustible gas ejected high, which helps to turbulently mix with the low-concentration organic waste gas fully and prevent the backflow of the combustible gas. The part of the spray head 30 located outside the mixing chamber 11 is connected to the fuel supply pipeline 21 through a connecting flange. Therefore, the fuel supply pipeline 21 supplies fuel into the spray head 30 and sprays it into the mixing chamber 11 through the spray holes 31.

[0070] Please refer to Figure 2As shown, a plurality of spray holes 31 are arranged along the axial direction of the spray head 30 itself. The fuel in the fuel supply pipe 21 enters the spray head 30 and is ejected through the spray holes 31. Since a plurality of spray holes 31 are provided, the fuel can be ensured to be evenly sprayed into the mixing chamber 11 to fully mix with the organic waste gas in the mixing chamber 11.

[0071] Combined with Figure 2 and Figure 3 As shown, to ensure that the fuel ejected from the spray holes 31 is fully mixed with the organic waste gas, the opening direction of the spray holes 31 is perpendicular to the opening direction of the first air inlet 12. That is, the opening direction of the spray holes 31 is perpendicular to the axial direction of the mixing unit 10, and the spray holes 31 are arranged in two rows and are respectively located on both sides of the spray head 30 along the direction perpendicular to the axial direction of the mixing unit 10. Combined with Figure 3 As shown, the fuel ejected through the spray holes 31 forms an air curtain perpendicular to its axial direction in the mixing unit 10. The waste gas flowing along the axial direction of the mixing unit 10 comes into full contact with and is evenly mixed with this air curtain, and after forming a mixed gas, it is supplied into the combustion furnace 300 through the air outlet 14.

[0072] In this embodiment, the fuel supply pipe 21 is used to supply gas and is ejected through the spray holes 31. In other alternative embodiments, the spray head 30 can adopt an atomizing spray head. The fuel supply pipe 21 can supply liquid fuel, and the liquid fuel is atomized and ejected through the spray head 30 to be mixed with the organic waste gas. The spraying principle of this spray head 30 is similar to that of the fuel injector of an engine, and will not be elaborated here. If the fuel supply pipe 21 supplies liquid fuel, the conveying distance from the air outlet 14 to the combustion furnace 300 should be minimized.

[0073] In this embodiment, the mixing of the fuel and the organic waste gas is achieved by the cylindrical mixing unit 10 cooperating with the spray head 30. In other alternative embodiments, the mixing unit 10 can adopt other shapes, such as a cuboid box structure, which can achieve the full mixing of the fuel and the organic waste gas by increasing the volume of the mixing chamber 11 or extending the conveying distance from the first air inlet 12 to the air outlet 14; the specific structure of the mixing unit 10 can be adjusted adaptively based on actual usage requirements, and will not be elaborated here.

[0074] Furthermore, please refer to Figure 1 As shown, the combustion system further includes a heat exchanger 400. In this embodiment, the heat exchanger 400 adopts a plate heat exchanger, which has a cold path and a hot path inside, and the medium in the cold path exchanges heat with the medium in the hot path.

[0075] As Figure 1As shown, the exhaust port of the combustion furnace 300 is connected to the hot path inlet 401 of the heat exchanger 400, and the hot path outlet 402 of the heat exchanger 400 is connected to the tail gas emission device 500. After the mixed gas of organic waste gas and fuel enters the combustion furnace for combustion, the high-temperature tail gas is subjected to heat exchange to realize waste heat utilization, and then is discharged after being treated up to standard by the tail gas emission device 500.

[0076] The cold path inlet 403 of the heat exchanger 400 is used to introduce combustion-supporting air, and the combustion-supporting air can be forcedly introduced into the cold path inlet 403 through a blower. The cold path outlet 404 of the heat exchanger 400 is connected to the air combustion-supporting gas port 301 of the combustion furnace 300. After the combustion-supporting air introduced through the cold path inlet 403 exchanges heat with the hot path in the heat exchanger 400, the temperature of the combustion-supporting air rises and then enters the furnace cavity of the combustion furnace 300 through the cold path outlet 404 and the air combustion-supporting gas port 301.

[0077] Through the setting of the heat exchanger 400, the high-temperature tail gas after the combustion of the combustion furnace 300 is used to heat the combustion-supporting air, realizing waste heat recovery, which helps to reduce the use of fuel, reduce the fuel consumed for preheating the combustion-supporting air, and thus reduce the operation cost.

[0078] In this embodiment, the heat exchanger 400 adopts a plate heat exchanger. In other alternative embodiments, the heat exchanger 400 can be of cast iron type, cylinder type, steel type, water storage type, etc. The type of the heat exchanger 400 can be selected adaptively based on actual requirements.

[0079] Please continue to refer to Figure 1 As shown, a gas emergency combustion-supporting port 302 is further provided on the combustion furnace 300, which is used to introduce fuel when the combustion furnace 300 is started or in other abnormal emergency situations to achieve the purpose of combustion support.

[0080] Please continue to refer to Figure 1 As shown, the combustion system further includes a flame arrester 600, and the flame arrester 600 is arranged between the mixing unit 10 and the waste gas source 200. The flame arrester 600 is a safety device used to prevent the spread of flames of flammable gases and flammable liquid vapors. The flame arrester 600 is installed on the pipeline between the mixing unit 10 and the waste gas source 200, which can prevent the gas on the combustion furnace 300 side from burning and spreading to the waste gas source 200 side through the pipeline, so as to prevent the propagation of flames and prevent flashback accidents. The flame arrester generally consists of two parts: a shell and a filter element. The filter element is located inside the shell, and the shell should have sufficient strength to withstand the impact pressure generated by the explosion. The filter element is the main component to prevent the propagation of flames, and there are generally two types: metal mesh filter element and corrugated filter element. The metal mesh filter element is composed of multiple layers of stainless steel or copper mesh overlapping. The corrugated filter element is supported by stainless steel, copper-nickel alloy, aluminum or aluminum alloy. The structure of the flame arrester 600 belongs to the prior art, and it can be selected based on the use requirements and will not be elaborated here.

[0081] Please continue to refer to Figure 1 As shown, the combustion system further includes a gas concentration detector 700, and the gas concentration detector 700 is disposed on the pipeline between the air outlet 14 and the air inlet of the combustion furnace 300. The gas concentration detector 700 is used to on-line detect the concentration of the mixed gas after being mixed by the mixing unit 10.

[0082] The gas concentration detector 700 is an instrument tool for detecting gas concentration. It mainly uses a gas sensor to detect the types and concentrations of gases existing in the mixed gas in the pipeline. The gas sensor is a sensor used to detect the components and content of gases. The gas concentration detector 700 can be divided into types such as electrochemical, catalytic combustion, infrared, semiconductor, thermal conduction, PID photoionization, etc.

[0083] In this embodiment, the gas concentration detector 700 can be selected as an MO type combustible gas concentration detector, which can detect the concentration of combustible gas in the mixed gas. The gas concentration detector 700 can also be selected as an instrument for detecting the concentration of composite gases, which is used to detect the components and concentrations of various gases in the mixed gas.

[0084] The gas concentration detector 700 belongs to the prior art. It can be selected based on actual usage requirements, and the principle, installation method, and usage method of the gas concentration detector 700 all belong to the prior art, and will not be elaborated here.

[0085] Please continue to refer to Figure 1 As shown, in this embodiment, the combustion system further includes a cut-off valve 800. The cut-off valve 800 is disposed on the pipeline between the air outlet 14 and the air inlet of the combustion furnace 300, and the cut-off valve 800 is located between the gas concentration detector 700 and the air inlet of the combustion furnace 300. The cut-off valve 800 is used in cooperation with the gas concentration detector 700. When the detected mixed concentration value or gas concentration value by the gas concentration detector 700 exceeds the limit, an alarm is given and the cut-off valve 800 is activated to cut off the pipeline between the air outlet 14 and the air inlet of the combustion furnace 300 to prevent high-concentration gas from entering the combustion furnace 300. The cut-off valve 800 can be an electromagnetic valve or other known valves. The cut-off valve 800 can be adaptively selected based on actual usage requirements, and will not be elaborated here.

[0086] Please continue to refer to Figure 1 As shown, the fuel supply unit 20 further includes a plurality of functional components disposed on the fuel supply pipeline 21.

[0087] Specifically, the fuel supply unit 20 further includes a voltage stabilizing component 22, a leakage detection component 23, and a flow rate regulating component 24.

[0088] The pressure stabilizing component 22 is arranged in the fuel supply pipeline 21 for adjusting the gas pressure in the fuel supply pipeline 21; the leakage detection component 23 is arranged in the fuel supply pipeline 21 for gas leakage detection; the flow regulating component 24 is arranged in the fuel supply pipeline 21 for adjusting the gas flow in the fuel supply pipeline 21.

[0089] In this embodiment, the pressure stabilizing assembly 22 includes a pressure stabilizing valve 221 , a high pressure switch 222 and a low pressure switch 223 which are arranged on the fuel supply pipeline 21 .

[0090] The high pressure switch 222 and the low pressure switch 223 are both gas pressure switches. Pressure switches include normally open and normally closed types. In this embodiment, the high pressure switch 222 and the low pressure switch 223 are normally open. The gas pressure switch is triggered by a certain pressure and then alarms. The triggering pressure of the high pressure switch 222 is greater than the triggering pressure of the low pressure switch 223.

[0091] Pressure switches include mechanical and electronic types. Mechanical pressure switches are micro switches that are activated by pure mechanical deformation. When the pressure increases, the different pressure sensing components (diaphragms, bellows, pistons) deform and move, and finally activate the micro switch through mechanical structures such as railing springs to output electrical signals. Electronic pressure switches use high-precision, high-stability pressure sensors and transmission circuits, and then use dedicated CPU modular signal processing technology to detect, display, alarm and control signal output of medium pressure signals. Pressure switches can be widely used in the fields of petroleum, chemical, metallurgy, electricity, water supply, etc. to measure and control the gauge pressure and absolute pressure of various gases and liquids. They are ideal intelligent measurement and control instruments for industrial sites.

[0092] In this embodiment, the high-pressure switch 222 and the low-pressure switch 223 can select existing pressure switches based on actual usage requirements, for example, a PS-type pressure switch can be selected. The structure, use principle, and installation method of the high-pressure switch 222 and the low-pressure switch 223 all belong to the existing technology and will not be repeated here.

[0093] When the gas pressure in the fuel supply pipe 21 rises to the trigger pressure of the high-pressure switch 222, the high-pressure switch 222 alarms and transmits a signal to the corresponding valve (for example, to the first cut-off valve 232 and the second cut-off valve 233, which will be detailed in the following content), causing the valve to actuate and cut off the fuel supply pipe 21. Or when the gas pressure in the fuel supply pipe 21 drops to the trigger pressure of the low-pressure switch 223, the low-pressure switch 223 alarms and transmits a signal to the corresponding valve, causing the valve to actuate and cut off the fuel supply pipe 21. Therefore, through the high-pressure switch 222 and the low-pressure switch 223, it is always ensured that the gas pressure in the fuel supply pipe 21 is between the trigger pressure of the high-pressure switch 222 and the trigger pressure of the low-pressure switch 223, so as to maintain the stability of the gas pressure in the fuel supply pipe 21. At the same time, the safety of the fuel supply pipe 21 is ensured by the cut-off function of the high-pressure switch 222 and the low-pressure switch 223 in cooperation with the corresponding valves.

[0094] The pressure stabilizing valve 221 is used to regulate the gas pressure in the fuel supply pipe 21 to stabilize the pressure and flow rate.

[0095] The pressure stabilizing valve 221 is also called a pressure reducing valve. It can reduce the inlet pressure to a required outlet pressure and rely on the energy of the medium itself to automatically maintain the stability of the outlet pressure. The pressure reducing valve is a throttling element with variable local resistance, that is, by changing the throttling area, the flow rate and the kinetic energy of the fluid are changed, resulting in different pressure losses, so as to achieve the purpose of pressure reduction. Then, relying on the regulation of the control and regulation system, the fluctuation of the pressure behind the valve is balanced with the spring force, so that the pressure behind the valve remains constant within a certain error range.

[0096] In this embodiment, the pressure stabilizing valve 221 can select an existing pressure stabilizing valve based on actual usage requirements. For example, the FMF type pressure stabilizing valve can be selected. The structure, working principle, and installation method of the pressure stabilizing valve 221 all belong to the prior art and will not be elaborated here.

[0097] In this embodiment, the high-pressure switch 222 and the low-pressure switch 223 are located between the pressure stabilizing valve 221 and the mixing unit 10. That is, the fuel introduced into the fuel supply pipe 21 first passes through the pressure stabilizing valve 221 for pressure stabilization, and then passes through the low-pressure switch 223 and the high-pressure switch 222 in sequence. The rated pressure of the pressure stabilizing valve 221 is between the trigger pressure of the high-pressure switch 222 and the trigger pressure of the low-pressure switch 223. When the high-pressure switch 222 and the low-pressure switch 223 are triggered, it means that the pressure stabilizing function of the pressure stabilizing valve 221 fails. At this time, the fuel supply pipe 21 is cut off by the first cut-off valve 232 and the second cut-off valve 233 (the first cut-off valve 232 and the second cut-off valve 233 will be detailed in the following content) to ensure the safety of the entire combustion system.

[0098] Please continue to refer to Figure 1As shown, the leakage detection component 23 includes a pressure detector 231, a first cut-off valve 232, and a second cut-off valve 233 disposed on the fuel supply pipe 21. The pressure detector 231 is located between the first cut-off valve 232 and the second cut-off valve 233. The first cut-off valve 232 is located on the side of the pressure detector 231 closer to the main fuel supply pipe 25, that is, the gas in the fuel supply pipe 21 sequentially passes through the first cut-off valve 232, the pressure detector 231, and the second cut-off valve 233.

[0099] In this embodiment, the pressure detector 231 is a pressure transmitter. A pressure transmitter is a pressure sensing device that converts pressure into a pneumatic signal or an electric signal for control and remote transmission. It can convert physical pressure parameters such as gas and liquid sensed by the pressure sensing element sensor into standard electrical signals to supply secondary instruments such as indicating alarm instruments, recorders, and solenoid valves for measurement, indication, and process adjustment.

[0100] The pressure transmitter is one of the most commonly used sensors in industrial practice. It is widely used in various industrial automatic control environments, involving many industries such as water conservancy and hydropower, railway transportation, intelligent buildings, production automation, aerospace, military, petrochemical, oil wells, power, ships, machine tools, and pipelines. The pressure detector 231 can select an existing pressure transmitter adaptively based on actual usage requirements. For example, an OPEC type pressure transmitter can be selected. The structure, usage principle, and installation method of the pressure transmitter all belong to the prior art and will not be elaborated here.

[0101] Both the first cut-off valve 232 and the second cut-off valve 233 are solenoid valves. For example, a VAG type solenoid valve can be selected. The first cut-off valve 232 and the second cut-off valve 233 can be used in cooperation with the pressure detector 231.

[0102] The above-mentioned leakage detection component 23 is mainly used for self-checking valve leakage at the initial stage of startup. During the detection process, first, the first cut-off valve 232 is in the closed state, and the second cut-off valve 233 is opened for 5 seconds and then closed to evacuate the gas in the pipe between the first cut-off valve 232 and the second cut-off valve 233. After waiting for 25 seconds, if the pressure detector 231 detects that the pressure has not risen, it means that the first cut-off valve 232 does not leak; then the first cut-off valve 232 is opened for 5 seconds and then closed to fill the pipe between the first cut-off valve 232 and the second cut-off valve 233 with gas. After waiting for 25 seconds, if the pressure detector 231 detects that the pressure has not dropped, it means that the second cut-off valve 233 does not leak.

[0103] In addition, the first cut-off valve 232 and the second cut-off valve 233 can also be used in cooperation with the high-pressure switch 222 and the low-pressure switch 223. The first cut-off valve 232 and the second cut-off valve 233 can cut off the fuel supply pipe 21 through the trigger signals of the high-pressure switch 222 and the low-pressure switch 223 to ensure the safety of the entire combustion system.

[0104] In addition, a gas alarm device can be installed in the external environment to detect whether there is a gas leak in the entire combustion system. The alarm device can be linked with the first cut-off valve 232 and the second cut-off valve 233. When the gas concentration in the environment is detected to exceed the standard, the first cut-off valve 232 and the second cut-off valve 233 quickly cut off the fuel supply pipeline 21. At this time, with the cooperation of the gas alarm device, the first cut-off valve 232 and the second cut-off valve 233, the function of cutting off the fuel pipeline in case of leakage can be realized.

[0105] In other alternative embodiments, the first cut-off valve 232 and the second cut-off valve 233 may not adopt solenoid valves. When the high-pressure switch 222 and the low-pressure switch 223 trigger an alarm, the first cut-off valve 232 and the second cut-off valve 233 are manually cut off.

[0106] In other alternative embodiments, the pressure detection member 231 can select other existing types of pressure sensors, and the first cut-off valve 232 and the second cut-off valve 233 can select other existing types of valves.

[0107] The combined use of the pressure detection member 231, the first cut-off valve 232 and the second cut-off valve 233 has the technical effect of detecting the self-leakage of the first cut-off valve 232 and the second cut-off valve 233, and also has the technical effect of detecting the leakage of local pipelines.

[0108] Please continue to refer to Figure 1 As shown, when the fuel supply unit 20 includes a flow regulation assembly 24, the flow regulation assembly 24 includes a flow regulating valve 241 provided on the fuel supply pipeline 21.

[0109] The flow regulating valve is also known as a self-acting balance valve, flow control valve, flow controller, dynamic balance valve, flow balance valve, and is an intuitive and simple flow regulation and control device.

[0110] Flow regulating valves are generally divided into two categories: linear stroke regulating valves and angular stroke regulating valves. Linear stroke regulating valves include single-seat valves, double-seat valves, sleeve valves, cage valves, angle valves, three-way valves, diaphragm valves, etc. Angular stroke regulating valves include butterfly valves, ball valves, eccentric rotary valves, etc. These valves achieve the switching or regulating function through rotational movement.

[0111] The flow regulating valve 241 can be selected adaptively based on actual usage requirements, such as selecting a ZJHP type regulating valve. The structure, operating principle, and installation method of the flow regulating valve 241 all belong to the prior art and will not be elaborated here.

[0112] The setting of the flow regulating valve 241 can adjust the gas flow rate in the fuel supply pipeline 21, thereby adjusting the fuel concentration introduced into the mixing unit 10. In addition, the flow regulating valve 241 can also be used in conjunction with the gas concentration detector 700. When the gas concentration detected by the gas concentration detector 700 is small, the gas flow rate can be increased by adjusting the flow regulating valve 241; when the gas concentration detected by the gas concentration detector 700 is large, the gas flow rate can be decreased by adjusting the flow regulating valve 241.

[0113] In this embodiment, a pressure stabilizing component 22, a leakage detection component 23, and a flow regulation component 24 are provided on the fuel supply pipeline 21. In other alternative embodiments, on the fuel supply pipeline 21, two or one of the pressure stabilizing component 22, the leakage detection component 23, and the flow regulation component 24 can be selected and installed based on actual usage requirements, and they can be arbitrarily combined based on actual usage requirements.

[0114] Please continue to refer to Figure 1 As shown, in this embodiment, the fuel supply unit 20 further includes functional components such as a main valve 26, a filter 27, a pressure fine-tuning valve 28, a first pressure gauge 291, and a second pressure gauge 292. The above-mentioned functional components are all provided on the fuel supply pipeline 21.

[0115] Among them, the main valve 26 is provided at one end of the fuel supply pipeline 21 close to the fuel supply main pipe 25, that is, the gas entering the fuel supply pipeline 21 first passes through the main valve 26. The main valve 26 is used to control the on-off of the fuel supply pipeline 21 from the source to ensure the safety of the entire combustion system.

[0116] In this embodiment, the main valve 26 adopts a ball valve. In other alternative embodiments, the main valve 26 can also adopt a butterfly valve, etc. The main valve 26 can be adaptively selected based on actual usage requirements.

[0117] The filter 27 is provided behind the main valve 26, that is, the gas entering the fuel supply pipeline 21 passes through the main valve 26 and then passes through the filter 27. The filter 27 is provided before other valves or functional components to ensure the normal use of other functional components.

[0118] The filter 27 mainly separates and captures impurities in natural gas through a filtering medium to ensure the purity, stability, and reliability of natural gas.

[0119] The filter mainly includes principles such as inertial filtration, diffusion filtration, and electrostatic filtration. Inertial filtration means that large-particle dust makes inertial motion along with the high-speed flow of natural gas. When the air current bypasses an obstacle, the dust deviates from the air current direction due to inertia and hits the filter element to be intercepted. Diffusion filtration means that small-particle dust makes random Brownian motion. The smaller the dust, the more intense the random motion and the more opportunities to hit the obstacle. Electrostatic filtration means that the filter material is charged electrostatically or the dust is charged electrostatically. The electrostatic force causes the dust to change its motion trajectory and hit the obstacle, or adhere more firmly to the medium.

[0120] In this embodiment, the gas filter 27 can be selected based on actual usage requirements. For example, a GFK-type gas filter can be selected. The structure, usage principle, and installation method of the gas filter 27 all belong to the prior art and will not be elaborated here.

[0121] Please continue to refer to Figure 1 As shown, the first pressure gauge 291 is arranged behind the gas filter 27, the second pressure gauge 292 is arranged behind the pressure fine-tuning valve 28, and the pressure fine-tuning valve 28 is located between the second pressure gauge 292 and the flow regulation component 24.

[0122] The second pressure gauge 292 is arranged adjacent to the mixing unit 10. The first pressure gauge 291 and the second pressure gauge 292 are used to detect the pressure at the inlet position and the outlet position of the fuel supply pipeline 21. The pressure fine-tuning valve 28 is also arranged near the outlet of the fuel supply pipeline 21 for fine-tuning the gas pressure in the fuel supply pipeline 21.

[0123] In addition, the voltage stabilization component 22 and the leakage detection component 23 are located between the first pressure gauge 291 and the flow regulation component 24. The setting order of each functional component can be adjusted based on actual usage requirements.

[0124] For the above combustion system, the functional components installed on the fuel supply pipeline 21 can be used for gas leakage detection and also have the function of regulating the fuel flow rate to further adjust the concentration of the mixed gas. The gas consumption automatically adjusts the flow regulating valve according to the furnace temperature of the combustion furnace, with safe operation and strong operability.

[0125] The above combustion system can be connected to the fan frequency converter, human-machine interface, and temperature recorder in the system respectively through the PLC controller via the Ethernet network communication module. The field instruments and controllers are connected to the I / O module of the PLC to form a complete control system.

[0126] The furnace temperature set value can be determined based on the actual waste gas composition. For example, the furnace temperature set value is 800°C to 870°C. When the concentration of organic waste gas is extremely low and the furnace temperature of the combustion furnace 300 is lower than the temperature lower limit of 800°C, the waste gas blending device 100 is started (for example, the fuel supply pipeline 21 is opened through valve control). The blending and concentration control program and the combustion control program of the combustion furnace can be manually selected on the human-machine interface. After injecting fuel, the combustion furnace will continue to heat up. When the temperature exceeds the temperature set upper limit of 870°C, the fuel injection stops to prevent overheating. Ensure that the combustion furnace operates within the temperature range of 800°C to 870°C so that the organic matter in the waste gas can be thermally degraded faster and more completely; by controlling the furnace temperature of the combustion furnace to adjust the injection of high-concentration fuel, it not only saves energy but also improves the safety and stability of the entire system.

[0127] Please refer to Figure 4 and Figure 5 As shown, it is another embodiment of the spray head 30. The blending unit 10 is provided with three spray heads 30. Each spray head 30 is arranged in parallel. Each spray head 30 extends along the axial direction perpendicular to the blending unit 10. Each spray head 30 is connected to the fuel supply pipeline 21. By setting multiple spray heads 30, the injection of a large flow of fuel can be satisfied.

[0128] Please refer to Figure 6 and Figure 7 As shown in the other embodiment of each spray head 30. The blending unit 10 is provided with three spray heads 30. Each spray head 30 extends along the radial direction of the blending unit 10 and is arranged around the axial direction of the blending unit 10. Each spray head 30 is connected to the fuel supply pipeline 21. By setting multiple spray heads 30 with circumferential uniform distribution, the injection of a large flow of fuel can be satisfied and it is also beneficial to the full mixing of the fuel and the organic waste gas in the blending unit 10.

[0129] In the above embodiments, each spray head 30 is provided with three. In other alternative embodiments, the number and distribution mode of the spray heads 30 can be adaptively adjusted based on actual usage requirements.

[0130] In this specification, each embodiment is described in a progressive manner. The key point of each embodiment is to illustrate the differences from other embodiments. For the same or similar parts among the embodiments, reference can be made to each other.

[0131] The above description is only a description of the preferred embodiments of the present invention, and does not limit the scope of the present invention in any way. Any changes and modifications made by those of ordinary skill in the art of the present invention based on the above disclosure shall fall within the protection scope of the claims.

Claims

1. An exhaust gas mixing device, characterized in that, Comprising: A blending unit and a fuel supply unit; The fuel supply unit includes a fuel supply pipeline; The blending unit has a blending chamber, and the blending unit is provided with a first air inlet, a second air inlet and an air outlet communicating with the blending chamber; The first air inlet is used to connect with an exhaust gas source, the second air inlet is connected to the fuel supply pipeline, and the air outlet is used to connect with the air inlet of a combustion furnace.

2. The exhaust gas mixing device according to claim 1, characterized in that The exhaust gas blending device further includes a spray head connected to the fuel supply pipeline, a part of the spray head passes through the second air inlet into the blending chamber, and the part of the spray head located in the blending chamber is provided with spray holes communicating with the fuel supply pipeline.

3. The exhaust gas mixing device according to claim 2, wherein, The opening directions of the first air inlet and the air outlet are the same and are oppositely arranged; and / or, the opening direction of the spray holes is perpendicular to the opening direction of the first air inlet.

4. The exhaust gas mixing device according to claim 1, characterized in that, The fuel supply unit further includes a pressure stabilizing component arranged on the fuel supply pipeline for regulating the air pressure in the fuel supply pipeline; and / or, the fuel supply unit further includes a leakage detection component arranged on the fuel supply pipeline for detecting gas leakage; and / or, the fuel supply unit further includes a flow rate regulating component arranged on the fuel supply pipeline for regulating the gas flow rate in the fuel supply pipeline.

5. The exhaust gas mixing device according to claim 4, characterized in that, When the fuel supply unit includes a pressure stabilizing component; The pressure stabilizing component includes a pressure stabilizing valve arranged on the fuel supply pipeline; And / or; The pressure stabilizing component includes a high-pressure switch and a low-pressure switch arranged on the fuel supply pipeline.

6. The exhaust gas mixing device according to claim 4, characterized in that, When the fuel supply unit includes a leakage detection component, the leakage detection component includes a pressure detection member, a first cut-off valve and a second cut-off valve arranged on the fuel supply pipeline, and the pressure detection member is located between the first cut-off valve and the second cut-off valve.

7. The exhaust gas mixing device according to claim 4, characterized in that, When the fuel supply unit includes a flow rate regulating component, the flow rate regulating component includes a flow rate regulating valve arranged on the fuel supply pipeline.

8. A combustion system, characterized in that, Comprising the exhaust gas blending device according to any one of claims 1 to 7, an exhaust gas source and a combustion furnace; the outlet end of the exhaust gas source is connected to the first air inlet, and the air inlet of the combustion furnace is connected to the air outlet.

9. The combustion system according to claim 8, wherein, The combustion system further includes a heat exchanger, the exhaust port of the combustion furnace is communicated with the hot path inlet of the heat exchanger, the cold path inlet of the heat exchanger is used for introducing combustion-supporting air, and the cold path outlet of the heat exchanger is communicated with the air-assisted combustion gas port of the combustion furnace.

10. The combustion system according to claim 9, characterized in that, The combustion system further includes a gas concentration detector arranged on the path between the air outlet and the air inlet of the combustion furnace.

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