Formaldehyde tail gas treatment device

Abstract

The utility model relates to a formaldehyde tail gas treatment device which comprises a tail gas conveying pipe and a natural gas conveying main pipe, and the outlet end of the tail gas conveying pipe is communicated with a tail gas combustion boiler. A first online chromatographic instrument, a first gas mixing tank and a second online chromatographic instrument are sequentially arranged on the tail gas conveying pipe in the direction from the position close to the tail gas combustion boiler to the position away from the tail gas combustion boiler, and a flue gas combustion header pipe is arranged on the tail gas combustion boiler; a dust remover, a first smoke conveying branch pipe and a first adjusting valve are sequentially arranged on the smoke combustion main pipe in the direction from the position close to the tail gas combustion boiler to the position away from the tail gas combustion boiler, a second adjusting valve is arranged on the first smoke conveying branch pipe, and the natural gas conveying main pipe and the first smoke conveying branch pipe are both communicated with the first gas mixing tank. And continuous and sufficient combustion of formaldehyde tail gas can be realized. And the device is convenient to adjust and use, and has a wide market prospect.

Description

Technical Field

[0001] The utility model relates to the field of formaldehyde tail gas processing equipment, in particular to a formaldehyde tail gas processing device. Background Art

[0002] Formaldehyde is a very useful chemical product, which can be used in coatings, paints, synthetic resins, wood processing and other industries. In industry, formaldehyde is often produced by the deoxidation and oxidation of methanol. In formaldehyde production, the formaldehyde tail gas discharged from the absorption tower has a generation amount of about 633 cubic meters of formaldehyde tail gas per ton of formaldehyde. The formaldehyde tail gas includes 17.5% to 21.5% hydrogen, 4.0% to 5.5% carbon dioxide, 0.3% to 0.8% methane, 0.2% to 0.6% carbon monoxide and 73.5% to 75.5% nitrogen. In addition, the formaldehyde tail gas also includes a small amount of water vapor, 700 mg per cubic meter of methanol and 300 mg per cubic meter of formaldehyde. Although the formaldehyde content in the formaldehyde tail gas is small, because formaldehyde has a strong odor and is a irritant, if it is directly discharged, it will cause great harm to nearby residents. At present, the formaldehyde manufacturers all adopt the direct combustion method for the treatment of formaldehyde tail gas. The reason is that the composition of formaldehyde exhaust gas is relatively complex, and the cost of separating and treating them one by one is too high for formaldehyde manufacturers. Another point is that direct combustion can incinerate trace amounts of formaldehyde gas in the exhaust gas, which is more thorough than other methods of formaldehyde treatment.

[0003] However, according to the composition of formaldehyde tail gas, we can conclude that formaldehyde tail gas is a mixed gas with low calorific value, and the emission of formaldehyde tail gas is limited by the load of formaldehyde production system. When the load of formaldehyde production system is too low, the flow rate of the components available for combustion in formaldehyde tail gas will be low. When the amount of components available for combustion is too low, the combustion of tail gas cannot be maintained, which will cause the flameout of tail gas boiler. When the boiler flameout stage, the components available for combustion carried in tail gas will be discharged to the atmosphere together, which will cause gas pollution. When the formaldehyde production system is under high load, the flow rate of the components available for combustion in the formaldehyde tail gas discharged by it will increase again. When the components available for combustion are transported to the tail gas boiler as air flow for combustion, the combustion of tail gas will be incomplete. The incomplete combustion tail gas still contains part of the gas available for combustion, which will still cause gas pollution when discharged to the atmosphere. Therefore, there is still room for improvement in the existing process for direct combustion of formaldehyde tail gas, in order to obtain stable formaldehyde tail gas that can be fully burned, so as to achieve continuous and stable treatment of formaldehyde tail gas, and then improve the promotion of corresponding technology. Summary of the invention

[0004] In view of the deficiencies in the prior art, the utility model provides a formaldehyde tail gas treatment device capable of achieving continuous and complete combustion of the formaldehyde tail gas, so as to overcome the defects in the prior art.

[0005] The technical solution adopted by the utility model is: a formaldehyde tail gas processing device, including a tail gas delivery pipe and a natural gas delivery main pipe, the outlet end of the tail gas delivery pipe is connected with a tail gas combustion boiler, the tail gas delivery pipe is provided with a first online chromatograph, a first mixing tank and a second online chromatograph in sequence along the direction from close to the tail gas combustion boiler to far away from the tail gas combustion boiler, the tail gas combustion boiler is provided with a flue gas combustion main pipe, the flue gas combustion main pipe is provided with a dust collector, a first flue gas delivery branch pipe and a first regulating valve in sequence along the direction from close to the tail gas combustion boiler to far away from the tail gas combustion boiler, the first flue gas delivery branch pipe is provided with a second regulating valve, and the natural gas delivery main pipe and the first flue gas delivery branch pipe are both connected with the first mixing tank.

[0006] Preferably, a second gas mixing tank is arranged between the first gas mixing tank and the first online chromatograph, a third online chromatograph is arranged between the second gas mixing tank and the first gas mixing tank, the first gas mixing tank and the second gas mixing tank each include a tank body, a first bend pipe, a first gas mixing cone, a second bend pipe and a second gas mixing cone are arranged on the tank body in sequence from the inlet end to the outlet end of the tank body, a first spiral blade is arranged between the first gas mixing cone and the tank body, a second spiral blade is arranged between the second gas mixing cone and the tank body, the inlet end of each first bend pipe is connected to the first flue gas delivery branch pipe, and the inlet end of each second bend pipe is connected to the natural gas delivery main pipe.

[0007] Preferably, the number of the second spiral blades and the number of the first spiral blades are both several, and the several second spiral blades and the several first spiral blades are distributed in a star shape on the outside of the central axis of the second mixing cone, and the central axis of the first mixing cone, the central axis of the second mixing cone, the central axis of the second bend pipe outlet end, and the central axis of the first bend pipe outlet end are located in the same straight line.

[0008] Preferably, a natural gas delivery branch pipe is respectively arranged between each second bend pipe and the natural gas delivery main pipe, a second smoke gas delivery branch pipe is respectively arranged between each first bend pipe and the first smoke gas delivery branch pipe, and a booster unit, a one-way valve, a first heat exchanger, and a buffer tank are respectively arranged on the first smoke gas delivery branch pipe between the second smoke gas delivery branch pipe and the second regulating valve and the natural gas delivery main pipe along the direction away from the exhaust gas delivery pipe to close to the exhaust gas delivery pipe, and a first pressure difference sensor and a pressure relief valve are arranged on the buffer tank.

[0009] Preferably, the natural gas transmission branch pipe and the second flue gas transmission branch pipe are respectively provided with a third regulating valve and a first gas flow sensor.

[0010] Preferably, a flameless burner is arranged between the outlet end of the exhaust gas delivery pipe and the combustion chamber of the exhaust gas combustion boiler, and the flameless burner includes a shell, a gas nozzle arranged on the shell, a third spiral blade arranged between the outlet end of the gas nozzle and the inner wall of the shell, an air distribution disk arranged on the third spiral blade and the gas nozzle, a venturi tube arranged on one end of the shell close to the outlet end of the gas nozzle, and a combustion-supporting gas connecting pipe arranged on the shell between the air distribution disk and the inlet end of the gas nozzle, and the inlet end of the gas nozzle is connected to the outlet end of the exhaust gas delivery pipe.

[0011] Preferably, the combustion-supporting gas connecting pipe is connected to an oxygen delivery pipe, and the oxygen delivery pipe is provided with a second pressure sensor, a second gas flow sensor and a fourth regulating valve in sequence along the direction from close to the combustion-supporting gas connecting pipe to away from the combustion-supporting gas connecting pipe, and a third pressure sensor and a third gas flow sensor are provided on the exhaust gas delivery pipe between the outlet end of the exhaust gas delivery pipe and the first online chromatograph.

[0012] The beneficial effects of the utility model are as follows: firstly, the utility model realizes that since the load of the formaldehyde production system is prone to fluctuations, the amount of combustible components in the formaldehyde tail gas transported out by the formaldehyde production system fluctuates, making it difficult to maintain continuous, stable and sufficient combustion of the formaldehyde tail gas. The product utilizes the natural gas transported through the natural gas transport main pipe and the incinerated tail gas transported through the flue gas combustion main pipe and the first flue gas transport branch pipe to supplement the formaldehyde tail gas, thereby enabling the formaldehyde tail gas to be continuously, stably and fully burned with methane as the main combustion component. In addition, since the incinerated tail gas transported by the first flue gas transport branch pipe is used as an inert gas to adjust the formaldehyde tail gas, it is also convenient to ensure that a variety of combustible components are all outside the explosion limit, thereby improving the safety of the use process.

[0013] Secondly, the oxygen delivery pipe of the utility model is provided with a second pressure sensor, a second gas flow sensor and a fourth regulating valve in sequence along the direction from close to the combustion-supporting gas connecting pipe to far away from the combustion-supporting gas connecting pipe. The installation of the second pressure sensor is convenient for feedback of pressure parameters, the installation of the second gas flow sensor is convenient for feedback of gas flow parameters, and the installation of the fourth regulating valve is convenient for adjusting the amount of oxygen delivered by the oxygen delivery pipe.

[0014] Finally, a third pressure sensor and a third gas flow sensor are arranged on the exhaust gas delivery pipe between the outlet end of the exhaust gas delivery pipe and the first online chromatograph of the utility model. Installing the third pressure sensor facilitates feedback of pressure parameters, and installing the third gas flow sensor facilitates feedback of flow parameters.

[0015] The utility model has the advantages of simple structure, convenient operation, ingenious design, greatly improved working efficiency, good social and economic benefits, and is a product that is easy to promote and use. BRIEF DESCRIPTION OF THE DRAWINGS

[0016] Figure 1 It is a structural schematic diagram of the utility model.

[0017] Figure 2 for Figure 1 A partial enlarged schematic diagram of detail A.

[0018] Figure 3 for Figure 1 A partial enlarged schematic diagram of detail B.

[0019] Figure 4 It is a structural schematic diagram of the components of the utility model. DETAILED DESCRIPTION

[0020] like Figures 1 to 4 As shown, a formaldehyde tail gas treatment device comprises a tail gas delivery pipe 1 and a natural gas delivery main pipe 2, the outlet end of the tail gas delivery pipe 1 is connected with a tail gas combustion boiler 3, the tail gas delivery pipe 1 is provided with a first online chromatograph 4, a first gas mixing tank and a second online chromatograph 5 in sequence along the direction from close to the tail gas combustion boiler 3 to far away from the tail gas combustion boiler 3, a flue gas combustion main pipe 6 is provided on the tail gas combustion boiler 3, the flue gas combustion main pipe 6 is provided with a second heat exchanger 41, a dust collector 7, a first flue gas delivery branch pipe 8 and a first regulating valve 9 in sequence along the direction from close to the tail gas combustion boiler 3 to far away from the tail gas combustion boiler 3, the first flue gas delivery branch pipe 8 is provided with a second regulating valve 10, the natural gas delivery main pipe 2 and the first flue gas delivery branch pipe 8 are both connected with the first gas mixing tank. A second gas mixing tank is arranged between the first gas mixing tank and the first online chromatograph 4, a third online chromatograph 11 is arranged between the second gas mixing tank and the first gas mixing tank, the first gas mixing tank and the second gas mixing tank each include a tank body 12, a first elbow 13, a first gas mixing cone 14, a second elbow 15 and a second gas mixing cone 16 are arranged on the tank body 12 in sequence from the inlet end to the outlet end of the tank body 12, a first spiral blade 17 is arranged between the first gas mixing cone 14 and the tank body 12, a second spiral blade 18 is arranged between the second gas mixing cone 16 and the tank body 12, the inlet end of each first elbow 13 is connected to the first flue gas delivery branch pipe 8, and the inlet end of each second elbow 15 is connected to the natural gas delivery main pipe 2.

[0021] For further information, please refer again to Figure 2 and Figure 4The number of the second spiral blades 18 and the number of the first spiral blades 17 are both several, and the several second spiral blades 18 and the several first spiral blades 17 are all distributed in a star shape outside the central axis of the second gas mixing cone 16, and the central axis of the first gas mixing cone 14, the central axis of the second gas mixing cone 16, the central axis of the outlet end of the second bend pipe 15, and the central axis of the outlet end of the first bend pipe 13 are located in the same straight line. Installing several first spiral blades 17 facilitates the full mixing of the formaldehyde tail gas delivered from the inlet end of the tank body 12 and the incineration tail gas of the first flue gas delivery branch pipe 8; installing several second spiral blades 18 facilitates the full mixing of the formaldehyde tail gas delivered from the inlet end of the tank body 12 and the natural gas of the natural gas delivery main pipe 2. A natural gas delivery branch pipe 19 is respectively provided between each second elbow pipe 15 and the natural gas delivery main pipe 2, a second flue gas delivery branch pipe 20 is respectively provided between each first elbow pipe 13 and the first flue gas delivery branch pipe 8, and a booster unit 21, a one-way valve 22, a first heat exchanger 23, and a buffer tank 24 are respectively provided on the first flue gas delivery branch pipe 8 between the second flue gas delivery branch pipe 20 and the second regulating valve 10, and the natural gas delivery main pipe 2 in the direction away from the exhaust gas delivery pipe 1 to close to the exhaust gas delivery pipe 1, and the buffer tank 24 is provided with a first pressure difference sensor 25 and a pressure relief valve 26. Furthermore, a third regulating valve 27 and a first gas flow sensor 28 are respectively provided on the natural gas delivery branch pipe 19 and the second flue gas delivery branch pipe 20. The installation of the first gas flow sensor 28 facilitates the feedback of the flow parameters of the gas delivered after being regulated by the third regulating valve 27.

[0022] In order to facilitate the complete combustion of formaldehyde tail gas, a flameless burner is arranged between the outlet end of the tail gas delivery pipe 1 described in this product and the combustion chamber of the tail gas combustion boiler 3. The flameless burner includes a shell 29, a gas nozzle 30 arranged on the shell 29, a third spiral blade 31 arranged between the outlet end of the gas nozzle 30 and the inner wall of the shell 29, an air distribution plate 32 arranged on the third spiral blade 31 and the gas nozzle 30, a venturi tube 33 arranged on one end of the shell 29 close to the outlet end of the gas nozzle 30, and a combustion-supporting gas connecting pipe 34 arranged on the shell 29 between the air distribution plate 32 and the inlet end of the gas nozzle 30. The inlet end of the gas nozzle 30 is connected to the outlet end of the tail gas delivery pipe 1. The shell 29 adopts a barrel-shaped structure with one end open, the gas nozzle 30 is installed through the sealed end of the shell 29, the central axis of the gas nozzle 30 and the central axis of the shell 29 are located in the same straight line, the combustion-supporting gas connecting pipe 34 is connected to the shell 29 outside the gas nozzle 30, and the venturi tube 33 includes a contraction section, a throat section and a release section in sequence from the inlet end of the venturi tube 33 to the outlet end of the venturi tube 33, the contraction section inlet end of the venturi tube 33 corresponds to the opening end of the shell 29, and the contraction section inlet end of the venturi tube 33 is connected to the opening end of the shell 29. Furthermore, due to the high proportion of nitrogen in the formaldehyde tail gas, And the total content of the components available for combustion in the formaldehyde tail gas is relatively low. In order to enable the components available for combustion in the formaldehyde tail gas to be fully burned and to reasonably control the flow rate of the tail gas after incineration, the combustion-supporting gas connecting pipe 34 described in this product is connected to an oxygen delivery pipe 35. The oxygen delivery pipe 35 is sequentially provided with a second pressure sensor 36, a second gas flow sensor 37 and a fourth regulating valve 38 along the direction from close to the combustion-supporting gas connecting pipe 34 to away from the combustion-supporting gas connecting pipe 34. A third pressure sensor 39 and a third gas flow sensor 40 are provided on the tail gas delivery pipe 1 between the outlet end of the tail gas delivery pipe 1 and the first online chromatograph 4.

[0023] The usage of this product is as follows: Figures 1 to 4 As shown, the following steps are included:

[0024] S1. The natural gas transmitted by the natural gas source is received by the natural gas transmission main pipe 2 and is pressurized by the booster unit 21 installed on the natural gas transmission main pipe 2. The natural gas is then sent to the buffer tank 24 installed on the natural gas transmission main pipe 2 for temporary storage as a pressurized natural gas source after countercurrent heat exchange through the heat source channel of the first heat exchanger 23 and the cold source that is continuously supplied to the cold source channel of the first heat exchanger 23. In addition, according to the parameters fed back by the first pressure difference sensor 25 installed on the buffer tank 24 on the natural gas transmission main pipe 2, the natural gas transmission main pipe 2 should be used to replenish the natural gas to the buffer tank 24, so that the parameters fed back by the first pressure difference sensor 25 are always within an appropriate range. When the system is started for the first time, nitrogen should be added to the buffer tank 24 on the first flue gas transmission branch pipe 8 as a substitute gas for the exhaust gas after combustion, so as to be used as an inert gas.

[0025] S2. The tail gas delivery pipe 1 receives the formaldehyde tail gas delivered by the upstream formaldehyde synthesis system and feeds back the component data of the tail gas through the second online chromatograph 5. The staff uses the burned tail gas stored in the buffer tank 24 installed on the first flue gas delivery branch pipe 8 as an inert gas to dilute the formaldehyde tail gas delivered to the tank body 12 of the second mixing tank through the corresponding second flue gas delivery branch pipe 20 according to the data fed back by the second online chromatograph 5, so that each component in the formaldehyde tail gas is outside the corresponding explosion limit, and the pressurized natural gas stored in the buffer tank 24 installed on the natural gas delivery main pipe 2 is supplemented and input into the tank body 12 of the second mixing tank through the corresponding natural gas delivery branch pipe 19, so as to increase the methane component in the formaldehyde tail gas and use it as the main combustible component for the combustion of the formaldehyde tail gas.

[0026] S3. The tank body 12 of the second mixing tank transports the formaldehyde tail gas after the first mixing to the outside and feeds back data through the third online chromatograph 11. The staff can then control and adjust the third regulating valve 27 on the second flue gas delivery branch pipe 20 connected to the first mixing pipe or the third regulating valve 27 on the natural gas delivery branch pipe 19 connected to the first mixing pipe, and use the combusted tail gas stored in the buffer tank 24 installed on the first flue gas delivery branch pipe 8 or the pressurized natural gas stored in the buffer tank 24 installed on the natural gas delivery main pipe 2 to supplement the formaldehyde tail gas after the first mixing in the tank body 12 of the first mixing tank with natural gas or inert gas to obtain the second mixed formaldehyde tail gas, so that the methane component in the second mixed formaldehyde tail gas is within an appropriate range. The second mixed formaldehyde tail gas continues to move along the tail gas delivery pipe 1 after the component content is fed back by the first online chromatograph 4.

[0027] S4. The second mixed formaldehyde tail gas is delivered to the gas nozzle 30 after the third pressure sensor 39 feedbacks the pressure parameter and the third gas flow sensor 40 feedbacks the flow parameter. According to the pressure parameter and the flow parameter fed back by the third pressure sensor 39 and the third gas flow sensor 40, the staff reasonably controls the opening of the fourth regulating valve 38 to gradually increase the delivery amount of oxygen delivered to the outer shell 29 of the gas nozzle 30 through the oxygen delivery pipe 35 and the auxiliary fuel gas connecting pipe 34 in sequence. The second mixed formaldehyde tail gas delivered to the venturi tube 33 through the outlet end of the gas nozzle 30 and the oxygen in the outer shell 29 of the gas nozzle 30 form combustion gas under the action of the third spiral blade 31 on the air distribution plate 32 and are continuously delivered to the combustion chamber of the tail gas combustion boiler 3. Finally, a stable combustion airflow is formed in the release section of the venturi tube 33 and the combustion chamber of the tail gas combustion boiler 3 to promote the full combustion of each component in the combustion gas.

[0028] S5. The combustion chamber of the exhaust gas combustion boiler 3 transports the exhaust gas to the flue gas combustion main pipe 6 to enter the heat source channel of the second heat exchanger 41 and continuously transports the exhaust gas to the cold source channel of the second heat exchanger 41 to form a cooled exhaust gas. After the particulate matter is removed by the dust collector 7, the first flue gas delivery branch pipe 8 is used to replenish the gas stored in the buffer tank 24 on the first flue gas delivery branch pipe 8 according to the parameters fed back by the first pressure difference sensor 25 installed on the buffer tank 24 on the first flue gas delivery branch pipe 8. The remaining cooled exhaust gas is discharged into the atmosphere through the flue gas combustion main pipe 6.

[0029] Through this embodiment, it is realized that since the load of the formaldehyde production system is prone to fluctuations, the amount of combustible components in the formaldehyde exhaust gas transported out by the formaldehyde production system fluctuates, making it difficult to maintain continuous, stable and sufficient combustion of the formaldehyde exhaust gas. This product utilizes the natural gas transported through the natural gas transmission main pipe 2 and the incinerated exhaust gas transported through the flue gas combustion main pipe 6 and the first flue gas transmission branch pipe 8 to supplement the formaldehyde exhaust gas, so that the formaldehyde exhaust gas can be continuously, stably and fully burned with methane as the main combustion component. In addition, since the incinerated exhaust gas transported by the first flue gas transmission branch pipe 8 is used as an inert gas to adjust the formaldehyde exhaust gas, it is also convenient to achieve that a variety of combustible components are all outside the explosion limit, thereby improving the safety of the use process.

[0030] The embodiments described above are only preferred embodiments of the present invention and are not intended to limit the scope of implementation of the present invention. Therefore, any equivalent changes or modifications made based on the structures, features and principles described in the patent scope of the present invention should be included in the patent application scope of the present invention.

Claims

1. A formaldehyde tail gas treatment device, characterized in that: The invention comprises an exhaust gas delivery pipe (1) and a natural gas delivery main pipe (2), wherein the outlet end of the exhaust gas delivery pipe (1) is connected to an exhaust gas combustion boiler (3), and the exhaust gas delivery pipe (1) is provided with a first online chromatograph (4), a first gas mixing tank and a second online chromatograph (5) in sequence from close to the exhaust gas combustion boiler (3) to far away from the exhaust gas combustion boiler (3); a flue gas combustion main pipe (6) is provided on the exhaust gas combustion boiler (3), and a dust collector (7), a first flue gas delivery branch pipe (8) and a first regulating valve (9) are provided on the flue gas combustion main pipe (6) in sequence from close to the exhaust gas combustion boiler (3) to far away from the exhaust gas combustion boiler (3); a second regulating valve (10) is provided on the first flue gas delivery branch pipe (8), and the natural gas delivery main pipe (2) and the first flue gas delivery branch pipe (8) are both connected to the first gas mixing tank.

2. The formaldehyde tail gas treatment device according to claim 1, characterized in that: A second gas mixing tank is arranged between the first gas mixing tank and the first online chromatograph (4), and a third online chromatograph (11) is arranged between the second gas mixing tank and the first gas mixing tank. The first gas mixing tank and the second gas mixing tank each comprise a tank body (12), a first curved pipe (13), a first gas mixing cone (14), a second curved pipe (15) and a second gas mixing cone (16) are arranged on the tank body (12) in sequence from the inlet end of the tank body (12) to the outlet end of the tank body (12), a first spiral blade (17) is arranged between the first gas mixing cone (14) and the tank body (12), and a second spiral blade (18) is arranged between the second gas mixing cone (16) and the tank body (12), the inlet end of each first curved pipe (13) is connected to the first flue gas transmission branch pipe (8), and the inlet end of each second curved pipe (15) is connected to the natural gas transmission main pipe (2).

3. The formaldehyde tail gas treatment device according to claim 2, characterized in that: The number of the second spiral blades (18) and the number of the first spiral blades (17) are both multiple, and the multiple second spiral blades (18) and the multiple first spiral blades (17) are distributed in a star shape outside the central axis of the second mixing cone (16), and the central axis of the first mixing cone (14), the central axis of the second mixing cone (16), the central axis of the outlet end of the second curved pipe (15), and the central axis of the outlet end of the first curved pipe (13) are located in the same straight line.

4. The formaldehyde tail gas treatment device according to claim 2, characterized in that: A natural gas delivery branch pipe (19) is provided between each second bend pipe (15) and the natural gas delivery main pipe (2), a second smoke delivery branch pipe (20) is provided between each first bend pipe (13) and the first smoke delivery branch pipe (8), and a booster unit (21), a one-way valve (22), a first heat exchanger (23), and a buffer tank (24) are provided on the first smoke delivery branch pipe (8) between the second smoke delivery branch pipe (20) and the second regulating valve (10) and the natural gas delivery main pipe (2) in a direction away from the exhaust gas delivery pipe (1) to close to the exhaust gas delivery pipe (1), and a first pressure difference sensor (25) and a pressure relief valve (26) are provided on the buffer tank (24).

5. The formaldehyde tail gas treatment device according to claim 4, characterized in that: The natural gas transmission branch pipe (19) and the second flue gas transmission branch pipe (20) are respectively provided with a third regulating valve (27) and a first gas flow sensor (28).

6. The formaldehyde tail gas treatment device according to claim 1, characterized in that: A flameless burner is arranged between the outlet end of the exhaust gas delivery pipe (1) and the combustion chamber of the exhaust gas combustion boiler (3), and the flameless burner comprises a shell (29), a gas nozzle (30) arranged on the shell (29), a third spiral blade (31) arranged between the outlet end of the gas nozzle (30) and the inner wall of the shell (29), an air distribution plate (32) arranged on the third spiral blade (31) and the gas nozzle (30), a venturi tube (33) arranged on one end of the shell (29) close to the outlet end of the gas nozzle (30), and a combustion-supporting gas connecting pipe (34) arranged on the shell (29) between the air distribution plate (32) and the inlet end of the gas nozzle (30), wherein the inlet end of the gas nozzle (30) is connected to the outlet end of the exhaust gas delivery pipe (1).

7. The formaldehyde tail gas treatment device according to claim 6, characterized in that: The combustion-supporting gas connecting pipe (34) is connected to an oxygen delivery pipe (35), and the oxygen delivery pipe (35) is provided with a second pressure sensor (36), a second gas flow sensor (37) and a fourth regulating valve (38) in sequence along a direction from close to the combustion-supporting gas connecting pipe (34) to far away from the combustion-supporting gas connecting pipe (34). A third pressure sensor (39) and a third gas flow sensor (40) are provided on the exhaust gas delivery pipe (1) between the outlet end of the exhaust gas delivery pipe (1) and the first online chromatograph (4).

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