A flue gas treatment device utilizing circulating flue gas

Abstract

The present invention provides a flue gas treatment device utilizing circulating flue gas, which can first recirculate the combustible industrial waste gas to reduce the amount of nitrogen oxides generated at the low-temperature combustion limit, and convert the nitrogen oxides in the flue gas into nitrogen and water for direct discharge. A combined pipe is arranged in a shell, and the front end of the combined pipe is respectively connected to a flue gas nozzle and an exhaust gas nozzle, and a secondary combustion-supporting air duct in a furnace is arranged on the front side of the combined pipe. The combustion-supporting air outlet of the secondary combustion-supporting air duct in the furnace extends forward over the outlet of the exhaust gas nozzle, and the outlet of the exhaust gas nozzle is located outside the secondary combustion-supporting air duct in the furnace, and the outlet of the flue gas nozzle is located outside the secondary combustion-supporting air duct in the furnace and at the rear side of the outlet of the exhaust gas nozzle. An ignition device is arranged on one side of the shell, and a material nozzle is also arranged at the center of the shell for introducing flue gas treatment materials.

Description

Technical Field

[0001] The invention relates to the technical field of waste gas utilization and treatment, and in particular to a flue gas treatment device utilizing recycled flue gas. Background Art

[0002] At present, a large amount of industrial waste gas is discharged in the production process of domestic petroleum and coal chemical enterprises, such as coke oven raw gas or simple treatment or process coke oven gas, blast furnace gas, coal bed gas, generator gas, city gas, biogas, calcium carbide furnace tail gas, carbon black tail gas. These industrial waste gases contain a large amount of combustible gases, among which the most contained are hydrogen, carbon monoxide and methane, which are extremely easy to burn or even explode. Some of them have high calorific value and are directly discharged into the atmosphere after being burned by sky lanterns, which not only causes huge waste but also seriously pollutes the environment. When burned, due to the complex composition, the same waste gas has different combustible components and impurities. Among the non-combustible components, many waste gases contain components that are prohibited from emission or have limited emission values ​​for environmental protection. In particular, all waste gases contain a large amount of nitrogen and nitrogen oxide components. If the nitrogen in the fuel gas is separated and treated, it will require a lot of The economic investment and daily processing costs bring great economic burden to enterprises. In order to reduce the nitrogen oxides generated in the combustion process, flue gas recirculation and cooling combustion are adopted. In the process of flue gas recirculation combustion, a part of the nitrogen is still oxidized by the instantaneous combustion temperature of the highly flammable hydrogen and carbon monoxide components in the exhaust gas, and its nitrogen oxide content has been greatly reduced, but the nitrogen oxide content in the fuel gas is different. Some exhaust flue gases still have excessive nitrogen oxides, which exceed the atmospheric emission standards and pollute the atmosphere and are restricted from use. With the improvement of the country's environmental protection requirements, many regions and cities have proposed ultra-low nitrogen emission requirements that are far higher than the national standards. For ultra-low nitrogen combustion of clean fuel natural gas, it is easy to achieve by flue gas recirculation, but for exhaust gas as fuel, it is impossible to achieve by burning natural gas. Summary of the invention

[0003] In view of the above problems, the present invention provides a flue gas treatment device utilizing recycled flue gas, which can recirculate the combustible industrial waste gas to reduce the amount of nitrogen oxides produced at the low-temperature combustion limit, and convert the nitrogen oxides in the flue gas into nitrogen and water for direct discharge without any secondary pollution, thereby effectively achieving standardized utilization of various industrial waste gases.

[0004] The technical scheme is as follows: a flue gas treatment device utilizing recycled flue gas comprises a shell and a flame tube connected to each other, the shell being respectively provided with an exhaust gas intake duct, a combustion-supporting air intake duct and a circulating flue gas intake duct, characterized in that: a combined duct is arranged in the shell, and the front end of the combined duct is respectively connected with a flue gas nozzle and an exhaust gas nozzle, the exhaust gas enters from the exhaust gas intake duct, passes through the combined duct and is ejected from the exhaust gas nozzle, the flue gas enters from the circulating flue gas intake duct, passes through the combined duct and is ejected from the flue gas nozzle, a secondary combustion-supporting air duct in the furnace is arranged on the front side of the combined duct, a combustion-supporting air inlet and a combustion-supporting air outlet are respectively arranged at both ends of the secondary combustion-supporting air duct in the furnace, the combustion-supporting air outlet of the secondary combustion-supporting air duct in the furnace extends forward over the outlet of the exhaust gas nozzle, and the outlet of the exhaust gas nozzle is located in the The vent of the exhaust gas nozzle is located outside the secondary combustion-supporting air duct in the furnace and behind the outlet of the exhaust gas nozzle. The secondary combustion-supporting air duct in the furnace divides the combustion-supporting air entering the shell into the primary combustion-supporting air outside the secondary combustion-supporting air duct in the furnace and the secondary combustion-supporting air inside the secondary combustion-supporting air duct in the furnace. An ignition device is arranged in the shell, and a flue gas treatment device is also arranged in the center of the shell. The flue gas treatment device includes a material nozzle, one end of the material nozzle is arranged as a flue gas treatment material inlet for introducing flue gas treatment material, and the other end of the material nozzle is arranged as a flue gas treatment material outlet. The flue gas treatment material outlet extends forward and crosses the combustion air outlet of the secondary combustion-supporting air duct in the furnace, and a material nozzle is arranged at the flue gas treatment material outlet.

[0005] Furthermore, the combined pipe includes an inner pipe and a jacket located outside the inner pipe, the jacket is respectively connected to the exhaust gas intake pipe and the exhaust gas nozzle to form a combustible exhaust gas channel, and the two ends of the inner pipe are respectively connected to the circulating flue gas intake pipe and the flue gas nozzle to form a flue gas channel.

[0006] Furthermore, the exhaust gas nozzles are arranged in a ring around the outer side of the secondary combustion-supporting air duct in the furnace, and the smoke gas nozzles are arranged in a ring around the outer side of the secondary combustion-supporting air duct in the furnace.

[0007] Furthermore, a diffusion type exhaust gas nozzle is provided at the outlet of the exhaust gas nozzle.

[0008] Furthermore, when the flue gas treatment material is gas, the material nozzle is a gas nozzle; when the flue gas treatment material is liquid, the material nozzle is an atomizing nozzle.

[0009] Furthermore, the material nozzle is placed in a supporting sheath pipe, and a high-temperature resistant supporting sheath pipe is provided at one end of the supporting sheath pipe close to the flue gas treatment material outlet, and a high-temperature resistant material nozzle is provided at one end of the material nozzle close to the flue gas treatment material outlet.

[0010] Furthermore, a return swirl plate is provided at the air outlet of the secondary combustion-supporting air duct in the furnace, which is used to generate return air that rotates toward the outside of the secondary combustion-supporting air duct in the furnace.

[0011] Furthermore, the ignition device includes an ignition tube arranged in the shell, one end of the ignition tube is connected to the ignition gas inlet, the other end of the ignition tube extends into the flame tube and is provided with an ignition and long-fire nozzle, an automatic ignition element is provided at the position of the ignition and long-fire nozzle, and the ignition and long-fire nozzle is arranged close to the outlet of the exhaust gas nozzle.

[0012] Furthermore, the exhaust gas intake pipe is provided with an exhaust gas electric regulating valve, the combustion air intake pipe is provided with an electric regulating damper, the circulating flue gas intake pipe is provided with a circulating flue gas electric regulating valve, and the flue gas treatment material inlet is provided with a material electric regulating valve.

[0013] Furthermore, an inspection door is provided on the shell, and the shell and the flame tube are connected as one body via a connecting flange.

[0014] The smoke treatment device utilizing circulating smoke of the present invention can realize diffusion-type delayed combustion extension by uniformly spraying circulating smoke around the exhaust gas nozzle, isolating the exhaust gas from the air, diffusing and diluting the exhaust gas, and then mixing it with the air for combustion, thereby reducing the temperature at the center of the combustion flame, preventing the generation of nitrogen oxides, and realizing low-nitrogen environmentally friendly emissions. At the same time, the exhaust gas combustion device is provided with a smoke treatment device, and the material nozzle of the smoke treatment device can directly spray the ammonia water generated by the smoke treatment material ammonia gas or ammonia water or urea and a catalyst solution after being heated to the smoke starting position at the tail of the combustion flame and fully mix it with the smoke, so that the nitrogen oxides and ammonia in the smoke are generated. Through biochemical reactions, nitrogen oxides are converted into nitrogen and water for direct discharge without any secondary pollution. At the same time, a dynamic control method can be adopted according to the specific content of nitrogen oxides, and the most economical amount of treatment materials can be used with the least adaptability. The injection amount of flue gas treatment materials can be changed according to the change of combustion load, and the treatment operation cost is greatly reduced. The standardized utilization of various industrial waste gases can be effectively achieved, and the heat generated can be effectively utilized. The comprehensive utilization of a large amount of industrial waste gases can not only reduce production costs for enterprises, but also respond to the requirements of the country's energy conservation, emission reduction and circular economy, and can create huge social and economic benefits. BRIEF DESCRIPTION OF THE DRAWINGS

[0015] Figure 1It is a front view schematic diagram of a flue gas treatment device utilizing circulating flue gas according to the present invention;

[0016] Figure 2 It is a side schematic diagram of a flue gas treatment device utilizing recycled flue gas according to the present invention. DETAILED DESCRIPTION

[0017] The technical solutions in the embodiments of the present invention will be described clearly and completely below in conjunction with the accompanying drawings in the embodiments of the present invention.

[0018] See Figure 1 , Figure 2 The present invention relates to a flue gas treatment device using circulating flue gas, comprising a shell 1 and a flame tube 2 connected to each other. The shell 1 is provided with an exhaust gas intake pipe 3, a combustion air intake pipe 4, and a circulating flue gas intake pipe 5. A combined pipe 6 is provided in the shell 1. The front end of the combined pipe 6 is connected with a flue gas nozzle 7 and an exhaust gas nozzle 8. The exhaust gas enters from the exhaust gas intake pipe 3, passes through the combined pipe 6, and is ejected from the exhaust gas nozzle 8. The flue gas enters from the circulating flue gas intake pipe 5, passes through the combined pipe 6, and is ejected from the flue gas nozzle 7. Two furnace internal pipes are provided on the front side of the combined pipe 6. The secondary combustion-supporting air duct 9, the exhaust gas nozzle 8 is arranged on the outside of the secondary combustion-supporting air duct 9 in the furnace, the exhaust gas nozzle 6 sprays the exhaust gas evenly around the secondary combustion-supporting air duct 7, which is used to disperse the exhaust gas, so that the combustion area is large and the flame temperature is reduced at the same load. The flue gas nozzle 7 is arranged on the outside of the secondary combustion-supporting air duct 9 in the furnace, and the two ends of the secondary combustion-supporting air duct 9 in the furnace are respectively provided with a combustion-supporting air inlet 901 and a combustion-supporting air outlet 902. The combustion-supporting air outlet 902 of the secondary combustion-supporting air duct in the furnace extends forward over the outlet 801 of the exhaust gas nozzle, and the outlet 801 of the exhaust gas nozzle is located in the secondary combustion-supporting air duct in the furnace. 9 and extends to the front end of the flame tube 2, the outlet 701 of the flue gas nozzle is located outside the secondary combustion-supporting air duct 9 in the furnace and behind the outlet 801 of the exhaust gas nozzle, the secondary combustion-supporting air duct 9 in the furnace divides the combustion-supporting air entering the shell 1 into the primary combustion-supporting air located outside the secondary combustion-supporting air duct 9 in the furnace and the secondary combustion-supporting air located inside the secondary combustion-supporting air duct 9 in the furnace, the circulating flue gas sprayed by the flue gas nozzle can block the exhaust gas from the primary combustion-supporting air and diffuse and dilute the exhaust gas, an ignition device is arranged in the shell 1, and a flue gas treatment device is also arranged in the center of the shell, the flue gas treatment device includes The material nozzle 10 includes a material nozzle 10, one end of which is arranged as a flue gas treatment material inlet 1001 for introducing the flue gas treatment material, and the other end of the material nozzle 10 is arranged as a flue gas treatment material outlet 1002, and the flue gas treatment material outlet 1002 extends forward over the combustion air outlet 902 of the secondary combustion air duct in the furnace, and a material nozzle 1003 is arranged at the flue gas treatment material outlet 1002. Specifically, when the flue gas treatment material is gas, the material nozzle 1003 is a gas nozzle; when the flue gas treatment material is liquid, the material nozzle 1003 is an atomizing nozzle.

[0019] Furthermore, the combined pipe 6 includes an inner pipe 601 and a jacket 602 located outside the inner pipe, the jacket 602 is respectively connected to the exhaust gas intake pipe 3 and the exhaust gas nozzle 8 to form a combustible exhaust gas channel, and the two ends of the inner pipe 601 are respectively connected to the circulating flue gas intake pipe 5 and the flue gas nozzle 7 to form a flue gas channel.

[0020] In this embodiment, a diffusion type exhaust gas nozzle 11 is provided at the outlet 801 of the exhaust gas nozzle for diffusing the exhaust gas into a hollow area, which is diluted by the circulating flue gas sprayed from the flue gas nozzle and then mixed with air for combustion, so that the flame area is large and the temperature is low.

[0021] In this embodiment, the material nozzle 10 is placed in the supporting sheath tube 13, and a high-temperature resistant supporting sheath tube 1301 is provided at one end of the supporting sheath tube 13 close to the flue gas treatment material outlet 1002. A high-temperature resistant material nozzle 1004 is provided at one end of the material nozzle 10 close to the flue gas treatment material outlet 1002. The material nozzle 10 transports the flue gas treatment material into the furnace, and sprays and mixes the material into the flue gas at the end of the flame through the material nozzle. The material nozzle 10 is divided into two parts, and the setting of the high-temperature resistant material nozzle 1004 can facilitate maintenance and replacement.

[0022] Specifically, a return swirl plate 14 is provided at the combustion air outlet 902 of the secondary combustion air duct in the furnace, which is used to generate return air that rotates toward the outside of the secondary combustion air duct in the furnace, so that the unburned exhaust gas in the furnace can be burned for the second time, and the flame can be burned on the periphery without accumulating heat in the middle to prevent the nozzle and the nozzle from overheating and burning.

[0023] Specifically in this embodiment, the ignition device includes an ignition tube 1501 arranged in the shell, one end of the ignition tube 1501 is connected to the ignition gas inlet 1502, the other end of the ignition tube 1501 extends into the flame tube and is provided with an ignition and long-fire nozzle, an automatic ignition element 1503 is provided at the position of the ignition and long-fire nozzle, and the ignition and long-fire nozzle is arranged near the outlet 801 of the exhaust gas nozzle.

[0024] In this embodiment, an exhaust gas electric regulating valve 16 is provided on the exhaust gas intake pipe 3, which can be used to adjust the intake amount of exhaust gas; an electric regulating damper 17 is provided on the combustion-supporting air intake pipe 4, which can be used to adjust the intake amount of air; a circulating flue gas electric regulating valve 18 is provided on the circulating flue gas intake pipe 5, which can be used to adjust the intake amount of circulating flue gas; a material electric regulating valve 19 is provided on the flue gas treatment material inlet 1001, which can be used to adjust the intake amount of flue gas treatment material, and the exhaust gas electric regulating valve 16, the electric regulating damper 17, the circulating flue gas electric regulating valve 18, and the material electric regulating valve 19 are respectively connected to electric actuators or servo motors.

[0025] In addition, in this embodiment, an inspection door 20 is provided on the housing 1, and the housing 1 and the flame tube 2 are connected as one body via a connecting flange 12, which is convenient for installation and maintenance.

[0026] The working process of the flue gas treatment device using circulating flue gas of the present invention is as follows: after the exhaust gas is introduced from the exhaust gas inlet pipe, it is diffused through the exhaust gas nozzle after passing through the combined pipe, and the exhaust gas is evenly sprayed around the secondary combustion-supporting air duct in the furnace, and the circulating flue gas is also diffused through the flue gas nozzle after passing through the combined pipe. The circulating flue gas blocks the exhaust gas from the primary combustion-supporting air and diffuses and dilutes the exhaust gas before mixing with the primary combustion-supporting air for combustion, which can realize the diffusion-type delayed extension of the combustion process, reduce the center temperature of the combustion flame, prevent the generation of nitrogen oxides, and realize low-nitrogen environmentally friendly emissions. Subsequently, the flame contacts and burns with the secondary combustion-supporting air, and the reflux swirl plate causes the secondary combustion-supporting air to generate reflux air that rotates toward the outside of the secondary combustion-supporting air duct in the furnace. The unburned exhaust gas in the furnace is subjected to secondary combustion, so that the flame does not gather heat in the middle of the outer combustion to prevent the nozzle and nozzle from overheating and burning. At the same time, the center temperature of the combustion flame is reduced to prevent the generation of nitrogen oxides, and low-nitrogen combustion and low-nitrogen environmentally friendly emissions are achieved. In addition, the material nozzle transports the flue gas treatment material into the furnace, and the material is sprayed and mixed into the flue gas at the end of the flame through the material nozzle. The flue gas treatment material such as ammonia or ammonia water or urea and catalyst solution is heated to produce ammonia water, which is directly sprayed to the starting position of the flue gas at the tail of the combustion flame and fully mixed with the flue gas, so that the nitrogen oxides and ammonia in the flue gas react chemically, and the nitrogen oxides are converted into nitrogen and water for direct discharge without any secondary pollution.

[0027] At the same time, the flue gas treatment device utilizing recycled flue gas of the present invention can adopt a dynamic control method according to the specific content of nitrogen oxides, and can adapt to the most economical amount of treatment materials with the least possible adaptability. The injection amount of the flue gas treatment material can be changed according to the change of the combustion load, and the treatment operation cost is greatly reduced. It can effectively realize the standardized utilization of various industrial waste gases, and effectively utilize the heat generated. It can comprehensively utilize a large amount of industrial waste gas, which can not only reduce the production cost for the enterprise, but also respond to the requirements of the country's energy conservation, emission reduction and circular economy, and can create huge social and economic benefits.

[0028] At present, when many users cannot meet the emission requirements by adopting flue gas recycling combustion, they perform denitrification treatment at the flue gas outlet, but the operation cost is high and it will also cause water pollution. The exhaust gas combustion device using recycled flue gas of the present invention can be used for various changes of combustible exhaust gases and meet the requirements of various places for ultra-low nitrogen emission indicators. It can also use industrial waste gas containing combustible gas in the most economical way to turn it into treasure, which not only protects the environment but also prevents a large amount of available heat from being wasted.

Claims

1. A flue gas treatment device using circulating flue gas, comprising a shell and a flame tube connected to each other, wherein the shell is respectively provided with an exhaust gas intake duct, a combustion air intake duct, and a circulating flue gas intake duct, characterized in that: A combined pipe is arranged in the shell, and a smoke nozzle and an exhaust gas nozzle are connected to the front end of the combined pipe respectively. The exhaust gas enters from the exhaust gas intake pipe, passes through the combined pipe and is ejected from the exhaust gas nozzle. The smoke enters from the circulating smoke gas intake pipe, passes through the combined pipe and is ejected from the smoke gas nozzle. A secondary combustion-supporting air duct in the furnace is arranged on the front side of the combined pipe. A combustion-supporting air inlet and a combustion-supporting air outlet are arranged at both ends of the secondary combustion-supporting air duct in the furnace respectively. The combustion-supporting air outlet of the secondary combustion-supporting air duct in the furnace extends forward over the outlet of the exhaust gas nozzle. The outlet of the exhaust gas nozzle is located outside the secondary combustion-supporting air duct in the furnace and extends to the front end of the flame tube. The outlet of the smoke nozzle is located outside the secondary combustion-supporting air duct in the furnace and extends to the front end of the flame tube. The secondary combustion-supporting air duct in the furnace is located outside the combustion-supporting air duct and at the rear side of the outlet of the exhaust gas nozzle. The secondary combustion-supporting air duct in the furnace divides the combustion-supporting air entering the shell into the primary combustion-supporting air located outside the secondary combustion-supporting air duct in the furnace and the secondary combustion-supporting air located inside the secondary combustion-supporting air duct in the furnace. An ignition device is arranged in the shell. A flue gas treatment device is also arranged in the center of the shell. The flue gas treatment device includes a material nozzle. One end of the material nozzle is arranged as a flue gas treatment material inlet for introducing flue gas treatment material. The other end of the material nozzle is arranged as a flue gas treatment material outlet. The flue gas treatment material outlet extends forward and crosses the combustion-supporting air outlet of the secondary combustion-supporting air duct in the furnace. A material nozzle is arranged at the flue gas treatment material outlet. The combined pipe comprises an inner pipe and a jacket located outside the inner pipe, the jacket is respectively connected to the exhaust gas intake pipe and the exhaust gas nozzle to form a combustible exhaust gas channel, and the two ends of the inner pipe are respectively connected to the circulating flue gas intake pipe and the flue gas nozzle to form a flue gas channel; The exhaust gas nozzle is arranged in a ring on the outer side of the secondary combustion-supporting air duct in the furnace, and the smoke gas nozzle is arranged in a ring on the outer side of the secondary combustion-supporting air duct in the furnace.

2. A flue gas treatment device using circulating flue gas according to claim 1, characterized in that: A diffusion type exhaust nozzle is arranged at the outlet of the exhaust nozzle.

3. A flue gas treatment device using circulating flue gas according to claim 1, characterized in that: When the flue gas treatment material is gas, the material nozzle is a gas nozzle; when the flue gas treatment material is liquid, the material nozzle is an atomizing nozzle.

4. A flue gas treatment device using circulating flue gas according to claim 1, characterized in that: The material nozzle is placed in a supporting sheath pipe, and a high-temperature resistant supporting sheath pipe is provided at one end of the supporting sheath pipe close to the flue gas treatment material outlet, and a high-temperature resistant material nozzle is provided at one end of the material nozzle close to the flue gas treatment material outlet.

5. The flue gas treatment device using circulating flue gas according to claim 1, characterized in that: A return swirl plate is provided at the air outlet of the secondary combustion-supporting air duct in the furnace, which is used to generate return air that rotates toward the outside of the secondary combustion-supporting air duct in the furnace.

6. A flue gas treatment device using recycled flue gas according to claim 1, characterized in that: The ignition device includes an ignition tube arranged in the shell, one end of the ignition tube is connected to the ignition gas inlet, the other end of the ignition tube extends into the flame tube and is provided with an ignition and long-fire nozzle, an automatic ignition element is arranged at the position of the ignition and long-fire nozzle, and the ignition and long-fire nozzle is arranged close to the outlet of the exhaust gas nozzle.

7. The flue gas treatment device using circulating flue gas according to claim 1, characterized in that: The exhaust gas intake pipe is provided with an exhaust gas electric regulating valve, the combustion-supporting air intake pipe is provided with an electric regulating damper, the circulating flue gas intake pipe is provided with a circulating flue gas electric regulating valve, and the flue gas treatment material inlet is provided with a material electric regulating valve.

8. The flue gas treatment device using recycled flue gas according to claim 1, characterized in that: An inspection door is arranged on the shell, and the shell and the flame tube are connected as one body via a connecting flange.

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