Waste gas recovery treatment device in production process of polypropylene spun-melt non-woven fabric

Abstract

The invention discloses a waste gas recovery treatment device in a polypropylene spun-melt non-woven fabric production process, which comprises a gas inlet unit, a pretreatment unit, a recovery unit, an advanced treatment unit, an adsorption and desorption regeneration unit and an exhaust unit which are communicated in sequence, and further comprises a control box, and each unit is connected with a valve through a pipeline; the gas inlet unit comprises a waste gas collecting cover, an induced draft fan and a gas flow meter, the waste gas collecting cover is installed at a waste gas discharge outlet of the spinning machine and the melt-blowing machine, a heat preservation layer is arranged on the inner wall, the induced draft fan is connected with the gas flow meter in series, and the gas flow meter is electrically connected with the control box. The use effect is good, two-stage pretreatment of cyclone separation and filter bag dust removal is adopted, and the dust removal rate reaches 99% or above; the combined process of condensation recovery and photocatalytic oxidation is optimized according to the characteristics of the polypropylene waste gas, the removal rate of VOCs reaches 95% or above, and it is ensured that the waste gas reaches the standard and is discharged.

Description

Technical Field

[0001] This invention relates to the field of waste gas recovery and treatment technology, specifically to a waste gas recovery and treatment device in the production process of polypropylene meltblown nonwoven fabric. Background Technology

[0002] In the production of polypropylene meltblown nonwoven fabric, processes such as spinning and meltblowing require heating the polypropylene raw material to a molten state. This process generates waste gas containing volatile organic compounds (VOCs), propylene monomer, and a small amount of dust. Directly discharging this waste gas not only wastes resources but also pollutes the atmosphere and harms the health of operators.

[0003] Existing waste gas treatment devices mostly employ single adsorption or combustion methods, which have significant drawbacks: in adsorption methods, the adsorbent is easily saturated and requires frequent replacement, and the treatment efficiency decreases over time; while combustion methods can decompose organic waste gas, they cannot recover usable components, have high energy consumption, and are prone to secondary pollution. Furthermore, some devices are not optimized for the characteristics of polypropylene waste gas, resulting in poor separation of dust and organic waste gas, overburdening subsequent treatment units and affecting the overall treatment quality.

[0004] Therefore, there is an urgent need for a waste gas recovery and treatment device that combines efficient separation, resource recovery, and environmental protection functions to address the shortcomings of existing technologies. Summary of the Invention

[0005] The purpose of this invention is to provide a waste gas recovery and treatment device in the production process of polypropylene meltblown nonwoven fabric, so as to solve the problems mentioned in the background art.

[0006] To achieve the above objectives, the present invention provides the following technical solution: a waste gas recovery and treatment device for the production process of polypropylene meltblown nonwoven fabric, comprising an air inlet unit, a pretreatment unit, a recovery unit, a deep treatment unit, an adsorption and desorption regeneration unit, and an exhaust unit connected in sequence, and also including a control box. Each unit is connected to a valve via a pipe. The air inlet unit includes a waste gas collection hood, an induced draft fan, and a gas flow meter. The waste gas collection hood is installed at the waste gas discharge port of the spinning machine and the meltblown machine, and its inner wall is provided with a heat insulation layer. The induced draft fan and the gas flow meter are connected in series, and the gas flow meter is electrically connected to the control box.

[0007] Preferably, the pretreatment unit includes a cyclone separator and a bag filter dust collector. The inlet of the cyclone separator is connected to the outlet of the induced draft fan, and a conical ash hopper and an ash discharge valve are provided at the bottom. The outlet of the cyclone separator is connected to the inlet of the bag filter dust collector. The bag filter dust collector is equipped with several polytetrafluoroethylene membrane filter bags, and a dust collection box is connected to the bottom.

[0008] Preferably, the recycling unit includes a condenser, the inlet of which is connected to the outlet of the bag filter dust collector, and the inside is provided with a multi-stage spiral condenser tube, through which a low-temperature coolant of -10℃ to 5℃ is circulated; the bottom of the condenser is provided with a liquid collection tank, which is connected to a polypropylene recycling tank through a pipe with a solenoid valve, and a liquid level sensor is provided in the liquid collection tank, and both the liquid level sensor and the solenoid valve are electrically connected to the control box.

[0009] Preferably, the adsorption and desorption regeneration unit includes an activated carbon adsorption tower and a control valve. The inlet of the activated carbon adsorption tower is connected to the outlet of the condenser recovery unit through a pipeline. The adsorption tower is filled with modified activated carbon adsorbent, which is modified by nitric acid acidification. The activated carbon adsorption tower is equipped with a pressure sensor and a temperature sensor at the bottom. Both the pressure sensor and the temperature sensor are electrically connected to the control box. The adsorption tower is wrapped with an insulation sleeve on the outside and has a serpentine heating tube inside.

[0010] Preferably, the deep processing unit includes a photocatalytic oxidation reactor, the inlet of which is connected to the outlet of the condenser recovery unit, and is equipped with ultraviolet lamps with wavelengths of 254nm and 185nm and a titanium dioxide photocatalytic plate inside, wherein the photocatalytic plate has a honeycomb structure.

[0011] Preferably, the upper outlet of the activated carbon adsorption tower is connected to the inlet of the condenser and the inlet of the photocatalytic oxidation reactor via a control valve. The control valve has three connection ports, labeled as port A, port B, and port C. The control valve is electrically connected to the control box to achieve automatic switching between adsorption and desorption modes.

[0012] Preferably, the exhaust unit includes a gas detection sensor and an exhaust stack. The gas detection sensor is installed on the outlet pipe of the photocatalytic oxidation reactor and is electrically connected to the control box. An online monitoring device is provided on the top of the exhaust stack, and the online monitoring device is connected to the data platform of the environmental protection department.

[0013] Preferably, the control box is a PLC controller, which is located on the outside of the filter bag dust collector housing and is electrically connected to the gas flow meter of the air inlet unit, the ash discharge valve of the pretreatment unit, the liquid level sensor and solenoid valve of the recovery unit, the ultraviolet lamp of the deep treatment unit, and the gas detection sensor of the exhaust unit, respectively, to realize automated control and linkage adjustment.

[0014] Preferably, the gas detection sensor is an online VOCs detector.

[0015] Preferably, the exhaust gas collection hood is made of stainless steel and the inner wall is lined with a 50mm thick rock wool insulation layer.

[0016] Compared with the prior art, the beneficial effects of the present invention are:

[0017] 1. This invention employs a two-stage pretreatment process of "cyclone separation + filter bag dust removal," achieving a dust removal rate of over 99%. An adsorption and desorption regeneration unit is added to connect condensation recovery and photocatalytic oxidation, enabling secondary recovery of low-concentration waste gas and recycling of the adsorbent. Combined with the "condensation recovery + photocatalytic oxidation" process, optimized for the characteristics of polypropylene waste gas, the VOCs removal rate reaches over 95%, ensuring that the waste gas meets emission standards.

[0018] 2. This invention accurately recovers high-concentration propylene monomer and high-boiling-point organic matter from waste gas through a condenser recovery unit, and then recovers low-concentration residual propylene monomer through an adsorption and desorption regeneration unit. The dual recovery mode increases the total recovery rate of propylene monomer to over 95%. The recovered polypropylene raw material has high purity and can be directly reused in non-woven fabric production, effectively reducing raw material costs and maximizing resource recycling.

[0019] 3. This invention eliminates the energy consumption of the adsorption and regeneration process. The photocatalytic oxidation reaction conditions are mild, requiring no high temperature or high pressure. The photocatalytic oxidation process produces no secondary pollution, only decomposing pollutants into harmless carbon dioxide and water. There is no waste leakage, which fully complies with the requirements of green production and environmental protection regulations.

[0020] 4. The adsorption and desorption regeneration unit of this invention is linked with the control box and condenser recovery unit. It can automatically switch between adsorption / desorption modes based on the pressure and temperature of the activated carbon adsorption tower and data from subsequent gas detection sensors, ensuring the stability of unit operation. At the same time, it further reduces the processing load of the deep treatment unit and improves the overall operating efficiency and service life of the device. Attached Figure Description

[0021] Figure 1 This is a schematic diagram of the overall structure of the waste gas recovery and treatment device in the production process of polypropylene meltblown nonwoven fabric according to the present invention.

[0022] Figure 2 This is a side view of the waste gas recovery and treatment device in the production process of polypropylene meltblown nonwoven fabric according to the present invention. Figure 1 ;

[0023] Figure 3 This is a side view of the waste gas recovery and treatment device in the production process of polypropylene meltblown nonwoven fabric according to the present invention. Figure 2 ;

[0024] Figure 4 This is a cross-sectional view of the waste gas recovery and treatment device in the production process of polypropylene meltblown nonwoven fabric according to the present invention.

[0025] Figure 5 This is a front view of the waste gas recovery and treatment device in the production process of polypropylene meltblown nonwoven fabric according to the present invention.

[0026] Figure 6This is a top view of the waste gas recovery and treatment device in the production process of polypropylene meltblown nonwoven fabric according to the present invention.

[0027] In the diagram: 1. Inlet unit; 11. Exhaust gas collection hood; 12. Exhaust fan; 13. Gas flow meter; 2. Pretreatment unit; 21. Cyclone separator; 22. Bag filter dust collector; 23. Conical ash hopper; 24. Ash discharge valve; 25. Dust collection box; 3. Recovery unit; 31. Condenser recovery unit; 32. Solenoid valve; 33. Spiral condenser tube; 34. Liquid collection tank; 35. Polypropylene recovery tank; 36. Liquid level sensor; 4. Adsorption and desorption regeneration unit; 41. Activated carbon adsorption tower; 42. Control valve; 5. Deep treatment unit; 51. Photocatalytic oxidation reactor; 52. Titanium dioxide photocatalytic plate; 53. Ultraviolet lamp; 6. Exhaust unit; 61. Gas detection sensor; 62. Exhaust stack; 63. Online monitoring device; 7. Control box. Detailed Implementation

[0028] The technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0029] Please see Figure 1-6 The present invention provides a technical solution: a waste gas recovery and treatment device in the production process of polypropylene meltblown nonwoven fabric, including an air inlet unit 1, a pretreatment unit 2, a recovery unit 3, an adsorption and desorption regeneration unit 4, a deep treatment unit 5 and an exhaust unit 6 connected in sequence, and also includes a control box 7. Each unit is connected to an electric valve through a corrosion-resistant pipe. The control box 7 adopts a PLC controller and is installed in an easy-to-operate position on the outside of the filter bag dust collector 22 housing.

[0030] In the air intake unit 1, the exhaust gas collection hood 11 is made of stainless steel and has a 50mm thick rock wool insulation layer on the inner wall. It is tightly fitted to the exhaust gas outlet of the spinning machine and the meltblown machine to ensure that the exhaust gas is collected without leakage. The induced draft fan 12 is a centrifugal induced draft fan with a rated air volume of 5000m³ / h. It is connected in series with a gas flow meter 13 with an accuracy of ±1% on the outlet pipe of the exhaust gas collection hood 11. The gas flow meter 13 is connected to the control box 7 through an RS5 communication line to transmit flow data in real time.

[0031] In the pretreatment unit 2, the processing air volume of the cyclone separator 21 is matched with that of the induced draft fan 12. Its inlet pipe is connected to the outlet pipe of the induced draft fan 12 by a flange. The cone angle of the bottom conical ash hopper 23 is 60°. The ash discharge valve 24 is an electric ash discharge valve, which is electrically connected to the control box 7. It can be set to open once per hour to discharge ash, with each discharge lasting 10 seconds. The outlet of the cyclone separator 21 is connected to the inlet of the bag filter dust collector 22. The bag filter dust collector 22 is equipped with 20 polytetrafluoroethylene membrane filter bags with a diameter of 130 mm and a length of 2000 mm. The filter bags are cleaned by pulse jet cleaning. The dust collection box 25 at the bottom has a volume of 1 m³, which is convenient for regular cleaning.

[0032] In the recycling unit 3, the shell of the condenser 31 is made of stainless steel, and the interior is equipped with three-stage spiral condenser tubes 33. The condenser tubes 33 are made of copper tubes with an inner diameter of 20 mm, and each stage of the condenser tube is 10 m long. The coolant inlet of the condenser tubes 33 is connected to the low-temperature refrigeration unit, and the coolant temperature is stabilized at -5℃ by controlling the refrigeration unit. The liquid accumulation tank 34 at the bottom of the condenser 31 has a volume of 0.5 m³, and an immersion-type liquid level sensor 36 is installed inside. The liquid level sensor 36 has a measurement range of 0-500 mm. When the liquid level reaches 400 mm, it triggers the opening of the solenoid valve 32. The solenoid valve 32 is made of stainless steel, and the connecting pipe diameter is 50 mm. The polypropylene recycling tank 35 has a volume of 5 m³ and is used to store the recycled propylene monomer.

[0033] In the adsorption and desorption regeneration unit 4, the activated carbon adsorption tower 41 is made of stainless steel with an effective volume of 1.5 m³. It is filled with 800 kg of nitric acid-modified activated carbon adsorbent. This modified activated carbon has a specific surface area of ​​850 m² / g and an adsorption capacity of 22 mg / g for low-concentration propylene monomer and VOCs. A pressure sensor is installed at the top of the activated carbon adsorption tower 41, with a measurement range of 0-0.1 MPa and an accuracy of ±0.5%. A temperature sensor is installed at the bottom, with a measurement range of 0-150℃ and an accuracy of ±1℃. Both are connected to the control box 7 via signal lines. The activated carbon adsorption tower 41 is wrapped with a 30 mm thick rock wool insulation sleeve, and a serpentine heating pipe is laid inside. The activated carbon adsorption tower 41 is made of 316L stainless steel, with a rated power of 15kW. The output temperature can be steplessly adjusted within the range of 80~120℃ via the control box 7. A control valve is installed on the outlet pipe of the activated carbon adsorption tower 41. The control valve is a three-way ball valve with ports A, B, and C. Port A of the control valve is connected to the outlet of the activated carbon adsorption tower 41. Port B is connected to the inlet pipe of the photocatalytic oxidation reactor 51 of the deep treatment unit 5 via a pipe. Port C is connected to the inlet of the condenser recovery unit via a pipe. The control valve is electrically connected to the control box 7. The control box 7 automatically switches the on / off state of the control valve according to the pressure value inside the activated carbon adsorption tower detected by the pressure sensor (the adsorption saturation pressure threshold is set to 0.08MPa), thereby realizing the switching between adsorption mode and desorption mode.

[0034] In the deep treatment unit 5, the effective volume of the photocatalytic oxidation reactor 51 is 2m³, and eight dual-wavelength ultraviolet lamps 53 with wavelengths of 254nm and 185nm are evenly arranged inside, each with a power of 150W; the titanium dioxide photocatalytic plate 52 adopts a honeycomb structure with a pore size of 10mm and a specific surface area of ​​500m² / m³, and is closely arranged around the ultraviolet lamps 53 to ensure that the exhaust gas is in full contact with the photocatalytic plate.

[0035] In the exhaust unit 6, the gas detection sensor 61 is a VOCs online detector with a measurement range of 0-100mg / m³ and an accuracy of ±2%. It is installed on the outlet pipe of the photocatalytic oxidation reactor 51 and electrically connected to the control box 7. When the detected VOCs concentration exceeds 20mg / m³, the control box 7 issues an audible and visual alarm. The exhaust stack 62 is 15m high and 800mm in diameter. The online monitoring device 63 installed on the top includes detection modules for VOCs, particulate matter, etc. It is connected to the local environmental protection department's data platform via a 4G network to upload detection data in real time.

[0036] The working process of this device is as follows:

[0037] 1. Waste gas collection: The waste gas generated by the spinning machine and the meltblown machine is collected through the waste gas collection hood 11 and enters the pipeline under the action of the induced draft fan 12. The gas flow meter 13 monitors the waste gas flow in real time and transmits the data to the control box 7.

[0038] 2. Pretreatment: The exhaust gas first enters the cyclone separator 21. Under the action of centrifugal force, dust particles with a diameter greater than 10μm are separated into the conical ash hopper 23 and periodically discharged into the dust collection box 25 through the ash discharge valve 24. The exhaust gas after preliminary dust removal enters the bag filter dust collector 22. The polytetrafluoroethylene membrane filter bags capture dust particles with a diameter less than 10μm. The dust falls into the bottom dust collection box 25. The exhaust gas after dust removal enters the recovery unit 3.

[0039] 3. Resource Recovery: The dust-removed exhaust gas enters the condenser 31 and comes into full contact with the internal spiral condenser 33. The high concentration of propylene monomer in the exhaust gas condenses and liquefies at a low temperature of -5℃, dripping into the liquid collection tank 34. When the liquid level sensor 36 detects that the liquid level in the liquid collection tank 34 reaches 400mm, it transmits a signal to the control box 7. The control box 7 controls the solenoid valve 32 to open, and the condensate flows into the polypropylene recovery tank 35. When the liquid level is below 100mm, the solenoid valve 32 closes. After condensation and recovery, low concentrations of propylene monomer and VOCs still remain in the exhaust gas, which then enters the adsorption and desorption regeneration unit 4.

[0040] 4. Adsorption and Desorption Regeneration: ① Adsorption Mode: Control box 7 controls the control valve to be in the A-to-B port connection state. Low-concentration waste gas enters the activated carbon adsorption tower 41. Through the adsorption of modified activated carbon adsorbent, propylene monomer and VOCs in the waste gas are further removed. The adsorbed waste gas enters the deep treatment unit 5. The pressure sensor monitors the pressure inside the activated carbon adsorption tower 41 in real time. When the pressure reaches 0.08MPa, it is determined that the adsorbent is saturated, and control box 7 triggers the desorption mode. ② Desorption Mode: Control box 7 controls the control valve to switch to the A-to-C port connection state. At the same time, the desorption heater is started, so that the temperature of the serpentine heating tube rises to 100℃ to heat and desorb the modified activated carbon adsorbent. The high-concentration propylene monomer vapor generated by desorption enters the condenser 31. After cooling and liquefaction, it forms condensate and is recycled again. After the desorption process lasts for 2 hours, control box 7 shuts off the desorption heater. After the temperature inside the activated carbon adsorption tower 41 drops to room temperature (temperature sensor detection value ≤30℃), the control valve is switched back to the adsorption mode to realize the recycling of the adsorbent.

[0041] 5. Deep treatment: After adsorption treatment, the waste gas enters the photocatalytic oxidation reactor 51. The 254nm and 185nm wavelength ultraviolet light emitted by the ultraviolet lamp 53 excites the titanium dioxide photocatalytic plate 52 and generates ozone. Under the combined action of photocatalysis and ozone oxidation, the remaining trace VOCs in the waste gas are completely degraded into water and carbon dioxide.

[0042] 6. Compliant Emissions: The exhaust gas after deep treatment is detected by the gas detection sensor 61. If the VOCs concentration is ≤20mg / m³, it is discharged through the exhaust stack 62, and the online monitoring device 63 uploads the exhaust data in real time. If the detected concentration exceeds the standard, the control box 7 issues an alarm and automatically increases the power of the ultraviolet lamp 53 to ensure that the exhaust gas meets the standard before being discharged.

[0043] Through the above embodiments, this device can achieve efficient treatment of waste gas from polypropylene spunbond nonwoven fabric production, with a dust removal rate of ≥99%, a total propylene monomer recovery rate of ≥95%, and a VOCs concentration in the treated waste gas of ≤20mg / m³, which fully meets environmental protection requirements. At the same time, it maximizes resource recovery and has significant economic and environmental benefits.

[0044] It should be noted that, in this document, relational terms such as "first" and "second" are used only to distinguish one entity or operation from another, and do not necessarily require or imply any such actual relationship or order between these entities or operations. Furthermore, the terms "comprising," "including," or any other variations thereof are intended to cover non-exclusive inclusion, such that a process, method, article, or apparatus that comprises a list of elements includes not only those elements but also other elements not expressly listed, or elements inherent to such process, method, article, or apparatus.

[0045] Although embodiments of the invention have been shown and described, it will be understood by those skilled in the art that various changes, modifications, substitutions and alterations can be made to these embodiments without departing from the principles and spirit of the invention, the scope of which is defined by the appended claims and their equivalents.

Claims

1. A waste gas recovery and treatment device in a polypropylene spunmelt nonwoven fabric production process, characterized by: The application relates to a waste gas treatment device, which comprises sequentially connected air inlet units (1), pretreatment units (2), recovery units (3), deep treatment units (5), adsorption and desorption regeneration units (4) and air outlet units (6), and further comprises a control box (7), wherein each unit is connected through pipelines and valves; the air inlet unit (1) comprises a waste gas collecting cover (11), an air draught fan (12) and a gas flow meter (13), the waste gas collecting cover (11) is installed at the waste gas discharge port of a spinning machine and a melt-blowing machine, an inner wall is provided with a heat preservation layer, the air draught fan (12) and the gas flow meter (13) are connected in series, and the gas flow meter (13) is electrically connected with the control box (7).

2. The polypropylene spunmelt nonwoven fabric production process waste gas recovery treatment device according to claim 1, characterized by: The pretreatment unit (2) comprises a cyclone separator (21) and a filter bag dust collector (22), the inlet of the cyclone separator (21) is communicated with the outlet of the air draught fan (12), the bottom of the cyclone separator (21) is provided with a conical ash hopper (23) and a dust discharging valve (24), the outlet of the cyclone separator (21) is communicated with the inlet of the filter bag dust collector (22), the inside of the filter bag dust collector (22) is provided with a plurality of polytetrafluoroethylene film filter bags, and the bottom of the filter bag dust collector (22) is connected with a dust collecting box (25).

3. The polypropylene spunmelt nonwoven fabric production process waste gas recovery treatment device according to claim 2, characterized by: The recovery unit (3) comprises a condensing recovery device (31), the inlet of the condensing recovery device (31) is communicated with the outlet of the filter bag dust collector (22), the inside of the condensing recovery device (31) is provided with a multistage spiral condensing pipe (33), low-temperature cooling liquid with a temperature of-10 DEG C to 5 DEG C is introduced into the multistage spiral condensing pipe (33), the bottom of the condensing recovery device (31) is provided with a liquid accumulation groove (34), the lower end of the liquid accumulation groove (34) is provided with an electromagnetic valve (32) and a polypropylene recovery tank (35), the liquid accumulation groove (34) is connected to the polypropylene recovery tank (35) through a pipeline provided with the electromagnetic valve (32), the inside of the liquid accumulation groove (34) is provided with a liquid level sensor (36), and the liquid level sensor (36) and the electromagnetic valve (32) are both electrically connected with the control box (7).

4. The polypropylene spunmelt nonwoven fabric production process waste gas recovery treatment device according to claim 3, characterized by: The adsorption and desorption regeneration unit (4) comprises an activated carbon adsorption tower (41) and control valves, the inlet of the activated carbon adsorption tower (41) is communicated with the outlet of the condensing recovery device (31) through a pipeline, the inside of the activated carbon adsorption tower (41) is filled with modified activated carbon adsorbents, the modified activated carbon is subjected to nitric acid modification treatment, the inside of the activated carbon adsorption tower (41) is provided with a pressure sensor and a temperature sensor, the pressure sensor and the temperature sensor are both electrically connected with the control box (7), the outside of the activated carbon adsorption tower (41) is wrapped with a heat preservation sleeve, and the inside of the activated carbon adsorption tower (41) is provided with a coiled heating pipe.

5. The polypropylene spunmelt nonwoven fabric production process waste gas recovery treatment device according to claim 4, characterized by: The deep treatment unit (5) comprises a photocatalytic oxidation reactor (51), the inlet of the photocatalytic oxidation reactor (51) is communicated with the outlet of the condensing recovery device (31), the inside of the photocatalytic oxidation reactor (51) is provided with ultraviolet lamps (53) with wavelengths of 254 nm and 185 nm and titanium dioxide photocatalytic plates (52), and the titanium dioxide photocatalytic plates (52) have a honeycomb structure.

6. The polypropylene spunmelt nonwoven fabric production process waste gas recovery treatment device according to claim 5, characterized by: The outlet of the activated carbon adsorption tower (41) is connected with the inlet of the condensing recovery device (31) and the inlet of the photocatalytic oxidation reactor (51) through control valves (42), respectively. The control valve (42) is provided with three connection ports, which are marked as A port, B port and C port, respectively. The control valve (42) is electrically connected with the control box (7) to realize automatic switching of the adsorption and desorption modes.

7. The polypropylene spunmelt nonwoven fabric production process waste gas recovery treatment device according to claim 6, characterized by: The exhaust unit (6) comprises a gas detection sensor (61) and an exhaust cylinder (62). The gas detection sensor (61) is installed on the outlet pipeline of the photocatalytic oxidation reactor (51) and is electrically connected with the control box (7). The exhaust cylinder (62) is provided with an online monitoring device (63) at the top. The online monitoring device (63) is connected with the data platform of the environmental protection department.

8. The polypropylene spunmelt nonwoven fabric production process waste gas recovery treatment device according to claim 7, characterized by: The control box (7) is a PLC controller. The control box (7) is arranged outside the shell of the filter bag dust collector (22) and is electrically connected with the gas flow meter (13) of the air inlet unit (1), the ash discharge valve (24) of the pretreatment unit (2), the liquid level sensor (36) and the electromagnetic valve (32) of the recovery unit (3), the ultraviolet lamp (53) of the adsorption and desorption regeneration unit (4) and the deep treatment unit (5), and the gas detection sensor (61) of the exhaust unit (6), so as to realize automatic control and linkage adjustment.

9. The polypropylene spunmelt nonwoven fabric production process waste gas recovery treatment device according to claim 8, characterized by: The gas detection sensor (61) is selected from a VOCs online detector.

10. The polypropylene spunmelt nonwoven fabric production process waste gas recovery treatment device according to claim 9, characterized by: The waste gas collecting cover (11) is made of stainless steel and is provided with a 50 mm thick rock wool heat preservation layer on the inner wall.

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