A graded deep treatment device and method for organic waste gas from textile coatings

Abstract

This invention discloses a graded deep treatment device and method for organic waste gas from textile coating processes. The treatment device includes a volatile organic waste gas system, a pretreatment system, a graded adsorption and recovery system, a heat comprehensive utilization system, a power system, and an exhaust system. Targeting high, medium-low, and low concentration organic waste gases generated in different stages of the textile industry, the system employs different levels of adsorption purification and condensation recovery for deep treatment, achieving a minimum emission concentration of less than 20 mg / m³. 3 The system forms a cycle within itself, and through an intelligent monitoring system, it controls the purification efficiency and the concentration at the outlet of the adsorption box to complete automatic adsorption, desorption, and regeneration. This achieves safe, efficient, and deep recycling purification without secondary pollution, stable and energy-saving operation, and can significantly improve economic and environmental benefits.

Description

Technical Field

[0001] This invention relates to the field of environmental protection, specifically to a device and method for the graded and in-depth treatment of organic waste gas from textile coatings. Background Technology

[0002] Volatile organic compounds (VOCs) are responsible for the formation of ozone (O3) and secondary PM2.5. 2.5 It is an important precursor to volatile organic compounds (VOCs). Currently, there are numerous technologies for treating VOCs, including adsorption, condensation, absorption, direct combustion, catalytic oxidation, UV photolysis, biological purification, and plasma purification. Depending on the specific conditions of the waste gas, such as its volume, concentration, temperature, humidity, the nature of the organic matter, and its value, different combinations of processes can be used for treatment. For example, for small volumes of high-concentration VOCs, those with recovery value are treated using adsorption + condensation recovery; those without recovery value are treated using direct combustion. For large volumes of low to medium concentration VOCs, adsorption concentration + catalytic oxidation / regenerative thermal combustion processes can be used.

[0003] In industrial waste gas treatment applications, different processes are typically employed to address different waste gas conditions. For a single enterprise, such as a textile printing and dyeing company, there are often various organic waste gas emission conditions. For example, there are organized emissions of high-concentration, high-temperature waste gas from the drying process, and organized and unorganized emissions of medium- and low-concentration, low-temperature waste gas from the coating process. Furthermore, especially since the implementation of the "Standard for Unorganized Emission Control of Volatile Organic Compounds" (GB 37822-2019), enterprises face the challenge of exceeding unorganized emission standards, requiring the conversion of low-concentration, ambient-temperature waste gas into organized emissions. Therefore, enterprises with numerous production processes often find themselves at a loss when selecting treatment technologies and equipment. Simultaneously, each waste gas treatment device requires energy consumption, such as power fans, heating devices, cooling devices, pumps, and instruments, and the simultaneous heating and cooling inevitably leads to energy imbalances and even waste throughout the plant. In the process of improving ambient air quality, with the implementation of emission standards and increasingly stringent control measures, enterprises need to complete relevant in-depth treatment processes. In the context of carbon peaking and carbon neutrality, the VOC emissions and relative energy consumption of a company's environmental protection equipment are crucial to its long-term stable development, and the pressure to reduce carbon emissions is increasing year by year. Therefore, a comprehensive approach based on the company's overall waste gas emissions is necessary, and in the long term, it must meet the requirements for in-depth treatment. However, there are currently no relevant reports on this topic.

[0004] CN105169886A reports a highly efficient and energy-saving device and method for the recovery and treatment of large-volume, low-concentration organic waste gas. This invention proposes a method for treating large-volume, low-concentration waste gas by first filtering, then adsorbing and concentrating the organic waste gas. After multiple heat exchanges to recover heat, condensation is performed to ultimately achieve waste gas treatment and solvent recovery. CN110548361A reports an organic waste gas recovery system and method, and CN105688596A reports a multi-component VOCs adsorption and condensation recovery device. Both of these methods focus on single-condition waste gas recovery and treatment, and partially recover energy through heat exchange. However, these existing technologies only address single-condition waste gas treatment without demonstrating effective treatment results. They lack the ability to adjust to fluctuations in operating conditions and do not offer a systematic solution for addressing the diverse waste gas emission treatment needs of enterprises. Summary of the Invention

[0005] The present invention aims to solve at least one of the above-mentioned problems in the prior art.

[0006] This invention provides a graded deep treatment device and method for organic waste gas from textile coatings, which can perform graded recycling and treatment for different waste gas emission conditions throughout the plant, ultimately achieving deep treatment and comprehensive energy utilization.

[0007] A graded deep treatment device for organic waste gas from textile coatings includes: a volatile organic waste gas system, a pretreatment system, a graded adsorption and recovery system, a heat comprehensive utilization system, a power system, and an exhaust system; the volatile organic waste gas system is connected to the pretreatment system, the graded recovery system, and the exhaust system in sequence via pipelines; the power system provides power to the volatile organic waste gas system; and the heat comprehensive utilization system provides heat to the graded deep treatment device for organic waste gas.

[0008] The textile coating organic waste gas system includes: a first gas collection hood for recovering high-concentration organic waste gas; a second gas collection hood for recovering medium- and low-concentration organic waste gas; and a third gas collection hood for recovering low-concentration organic waste gas.

[0009] The pretreatment system includes: a first filter, a second filter, a third filter, and a dehumidifier; the exhaust gas inlet of the first filter is connected to the exhaust gas outlet of the first gas collection hood; the exhaust gas inlet of the second filter is connected to the exhaust gas outlet of the second gas collection hood; the exhaust gas inlet of the third filter is connected to the exhaust gas outlet of the third gas collection hood; the dehumidifier is also provided with a non-condensable gas inlet;

[0010] The graded adsorption and recovery system includes: a primary spray tower, a primary activated carbon fiber adsorption box, a secondary molecular sieve rotor adsorption box, a tertiary fixed bed adsorption box, a condensation and recovery device, a gas-liquid separator, and a recovered solvent storage tank.

[0011] The comprehensive heat utilization system includes: a first heat exchanger, a second heat exchanger, a third heat exchanger, and a low-NOx combustion boiler.

[0012] The power system includes: a first adsorption fan, a second adsorption fan, a first desorption fan, a second desorption fan, an exhaust fan, and a circulation pump;

[0013] The exhaust system includes a chimney.

[0014] This invention relates to a graded deep treatment device for organic waste gas from textile coating processes. It addresses three different concentrations of organic waste gas (high, medium, and low) generated at different stages of the process by employing different levels of adsorption purification and condensation recovery for deep treatment. The lowest emission concentration can be below 20 mg / m³. 3 The system forms a cycle within the system, and through an intelligent monitoring system, it controls the purification efficiency and the concentration at the outlet of the adsorption box to complete automatic adsorption, desorption, and regeneration. This achieves safe, efficient, and deep recovery and purification without secondary pollution, ensuring stable, energy-saving operation and significantly improving both economic and environmental benefits. A natural gas-fired low-NOx boiler provides the heat source and steam, fully utilizing heat energy through multi-stage heat exchange while also incinerating valueless waste gases, meeting ultra-low emission standards for both volatile organic compounds and nitrogen oxides. A combination of fixed-bed and molecular sieve rotors is used, with a dynamic and static adjustment mechanism. Highly efficient hydrophobic molecular sieve adsorption materials are employed for deep purification, offering high adjustability to meet the needs of different production conditions, achieving ultra-low purification while avoiding the economic losses associated with repeated upgrades.

[0015] This invention also provides a method for the graded and in-depth treatment of volatile organic waste gas from textile coatings, using the aforementioned graded and in-depth treatment device for volatile organic waste gas. The method includes the following steps:

[0016] 1) Waste gas collection process: Collect high-concentration organic waste gas, medium-low concentration organic waste gas and low-concentration organic waste gas separately;

[0017] 2) Pretreatment process: High-concentration organic waste gas, medium-low concentration organic waste gas and low-concentration organic waste gas are respectively fed into the pretreatment system for treatment, so that the particulate matter, grease, paint mist and temperature of the waste gas meet the requirements of the downstream treatment process.

[0018] 3) Staged adsorption and purification process:

[0019] High-concentration volatile organic waste gas after pretreatment enters the spray tower. The spray liquid is selected based on the properties of the waste gas to be treated and the principle of similar compatibility, and primary recovery is carried out to reduce the concentration of the waste gas.

[0020] After primary spraying, the exhaust gas is dehumidified and then enters the primary activated carbon fiber adsorption box for adsorption and separation purification. Volatile organic components are adsorbed into the pores by the activated carbon fiber material, thus separating the organic components from the exhaust gas. The separated organic exhaust gas is initially purified.

[0021] The secondary molecular sieve rotary adsorption box collects two sources of waste gas: one part comes from the gas purified by the primary adsorption, and the other part comes from the pretreated waste gas with medium and low concentrations of organic waste gas. The combined organic waste gas enters the secondary molecular sieve rotary adsorption box for secondary adsorption purification. Volatile organic components are adsorbed into the pores by the molecular sieve material, realizing the further separation of organic components from the waste gas. The separated organic waste gas is purified again, and the concentration of organic matter in the waste gas is further reduced.

[0022] The three-stage fixed-bed adsorption box collects two sources of waste gas: one is the gas purified by the second-stage adsorption, and the other is the waste gas after pretreatment of low-concentration organic waste gas. The combined organic waste gas enters the three-stage fixed-bed adsorption box for three-stage purification. Volatile organic components are adsorbed into the pores by the adsorption material, realizing the further separation of organic components from the waste gas. The separated organic waste gas is deeply purified and can be directly discharged into the air through the chimney.

[0023] 4) Desorption and Concentration Process

[0024] When the gas obtained by multi-stage adsorption purification in the above-mentioned 3) staged adsorption purification process reaches the controlled purification efficiency and controlled concentration value, the purified gas is discharged from the outlet of the adsorption box. At the same time, the adsorption box enters the desorption and regeneration process, and the desorbed gas desorbs the organic matter in the adsorption material in the adsorption box at an appropriate temperature.

[0025] The high-concentration organic waste gas desorbed from the primary activated carbon fiber adsorption box is cooled by heat exchange and then enters the next step of condensation and recovery; the high-concentration organic waste gas desorbed from the hot air in the secondary and tertiary adsorption boxes is cooled by heat exchange and then returned to the primary spray tower, where it is combined with the pretreated high-concentration organic waste gas and continues to enter the primary activated carbon fiber adsorption box for purification, forming a cycle.

[0026] 5) Condensation recovery process

[0027] The primary activated carbon adsorption box is regenerated by high-temperature steam desorption, forming an organic solvent-water mixture. This mixture enters a heat exchanger for heat exchange, and then passes through a condensation recovery device for cooling and liquefaction, forming an organic solvent-water mixture. This mixture, along with non-condensable gas, enters a gas-liquid separator for separation, achieving the separation of organic solvent and water, as well as the separation of the mixture from the non-condensable gas. The separated organic solvent enters a solvent recovery storage tank, while the non-condensable gas enters a dehumidifier and then re-enters the primary activated carbon fiber adsorption box for circulating purification.

[0028] This invention has at least one of the following beneficial effects:

[0029] 1. This invention is characterized by different concentrations of organic waste gas under different operating conditions, and selectively graded adsorption and recovery is carried out. The purification efficiency of different levels of adsorption boxes can be controlled, and the deep treatment of waste gas can be achieved. It also forms a complete set of waste gas treatment devices and synergistic treatment methods for the whole plant.

[0030] 2. Through multiple cyclic adsorption and recovery processes and intelligent control within the device, the recovery and emission reduction of organic waste gas can be maximized, thereby reducing the problem of increased carbon emissions for enterprises caused by direct VOCs emissions or direct incineration.

[0031] 3. This invention prioritizes maximizing the recovery efficiency of high-value organic matter while also addressing the treatment of organic waste gas with no or low recovery value. An intelligent monitoring system can determine and selectively treat the waste gas using a low-NOx natural gas combustion boiler, increasing the flexibility of the entire equipment and process. Furthermore, the use of a low-NOx burner eliminates the additional thermal NOx generated during combustion; the heat released from the combustion of organic matter is used to produce steam.

[0032] 4. This invention achieves maximum energy utilization through a comprehensive heat utilization system, and monitors and allocates energy through an intelligent monitoring system, thereby achieving energy balance of the entire device and reducing energy consumption in a planned and targeted manner.

[0033] 5. This invention uses a combination of a fixed bed and a molecular sieve rotor, with one moving and one stationary, to adjust the mixture. At the same time, it uses high-efficiency adsorption materials for deep purification, which is highly adjustable and can meet the needs of different production conditions of enterprises. It achieves ultra-low purification while avoiding the economic losses caused by repeated upgrades. Attached Figure Description

[0034] Figure 1 and Figure 2 This is a schematic diagram of a graded deep treatment device for organic waste gas from textile coatings.

[0035] Figure 3 This describes the coating process and the main pollution-generating stages. Detailed Implementation

[0036] The present invention will now be described in detail with reference to the accompanying drawings and specific embodiments. The following description is for illustrative and explanatory purposes only and does not constitute any limitation on the present invention.

[0037] It should be noted that the terms "first," "second," etc., are used for descriptive purposes only and should not be construed as indicating or implying relative importance or implicitly specifying the number of indicated technical features. Therefore, a feature defined with "first," "second," etc., may explicitly or implicitly include one or more of that feature. Furthermore, in the description of this invention, unless otherwise stated, "a plurality of" means two or more.

[0038] like Figure 1 As shown, this embodiment provides a graded deep treatment device for organic waste gas from textile coatings, including a volatile organic waste gas system 1, a pretreatment system 2, a graded adsorption and recovery system 3, a heat comprehensive utilization system 4, a power system 5, and an exhaust system 6.

[0039] In this embodiment, the volatile organic waste gas system 1 is connected to the pretreatment system 2, the graded recovery system 3 and the exhaust system 6 in sequence through pipelines; the power system 5 provides power to the volatile organic waste gas system 1, and the heat comprehensive utilization system 4 provides heat to the volatile organic waste gas graded deep treatment device in this embodiment and makes full use of it.

[0040] like Figure 2 As shown, the textile coating organic waste gas system 1 includes: a first gas collection hood 1-1 for recovering high-concentration organic waste gas; a second gas collection hood 1-2 for recovering medium- and low-concentration organic waste gas; and a third gas collection hood 1-3 for recovering low-concentration organic waste gas.

[0041] In some examples, the first gas collection hood 1-1, the second gas collection hood 1-2, and the third gas collection hood 1-3 are all equipped with exhaust gas inlets and exhaust gas outlets.

[0042] In some instances, high-concentration organic waste gas is recovered and collected by the first gas collection hood 1-1; medium- and low-concentration organic waste gas is recovered and collected by the second gas collection hood 1-2; and low-concentration organic waste gas is recovered and collected by the third gas collection hood 1-3.

[0043] The pretreatment system 2 includes: a first filter 2-1, a second filter 2-2, a third filter 2-3, and a dehumidifier 2-4; each of the first filter 2-1, the second filter 2-2, the third filter 2-3, and the dehumidifier 2-4 is provided with an exhaust gas inlet and an exhaust gas outlet; the exhaust gas inlet of the first filter 2-1 is connected to the exhaust gas outlet of the first gas collection hood 1-1; the exhaust gas inlet of the second filter 2-2 is connected to the exhaust gas outlet of the second gas collection hood 1-2; the exhaust gas inlet of the third filter 2-3 is connected to the exhaust gas outlet of the third gas collection hood 1-3; and the dehumidifier 2-4 is also provided with a non-condensable gas inlet.

[0044] The graded adsorption and recovery system 3 includes:

[0045] The primary spray tower 3-1 is provided with an exhaust gas outlet, a circulating spray liquid inlet, a circulating spray liquid outlet, and at least two exhaust gas inlets; one of the exhaust gas inlets is connected to the exhaust gas outlet of the first filter 2-1, and the exhaust gas outlet is connected to the exhaust gas inlet of the dehumidifier 2-4.

[0046] The primary activated carbon fiber adsorption box 3-2 is equipped with a waste gas inlet, a purified gas outlet, a high-temperature water vapor inlet, and a desorption gas outlet. Its waste gas inlet is connected to the waste gas outlet of the dehumidifier 2-4.

[0047] The secondary molecular sieve rotor adsorption box 3-3 is equipped with a waste gas inlet, a purified gas outlet, a hot air inlet, and a desorbed gas outlet;

[0048] The three-stage fixed bed adsorption box 3-4 is equipped with a purified gas outlet, a hot air inlet, a desorbed gas outlet, and at least one or two waste gas inlets;

[0049] The condensation recovery unit 3-5 is equipped with a condensation and concentration gas inlet and a condensation and concentration gas outlet.

[0050] Gas-liquid separator 3-6 is equipped with a condensate concentrate inlet, a non-condensable gas outlet, a recovered solvent outlet, and a valueless gas emission outlet.

[0051] The solvent recovery storage tank 3-7 is equipped with a solvent recovery inlet and a solvent recovery outlet.

[0052] The heat utilization system 4 includes:

[0053] The first heat exchanger 4-1 is equipped with a purified gas inlet, a purified gas outlet, a desorbed gas inlet, and a concentrated gas outlet;

[0054] The second heat exchanger 4-2 is equipped with a purified gas inlet, a purified gas outlet, a concentrated gas inlet, and a concentrated gas outlet;

[0055] The third heat exchanger 4-3 is equipped with a high-temperature steam inlet, a high-temperature steam outlet, a purified gas inlet, and a purified gas outlet;

[0056] The low-NOx combustion boiler 4-4 is equipped with an exhaust gas inlet, a natural gas inlet, a deionized water inlet, a high-temperature steam outlet, and a post-combustion gas exhaust outlet.

[0057] The power system 5 includes: a first adsorption fan 5-1, a second adsorption fan 5-2, a first desorption fan 5-3, a second desorption fan 5-4, an exhaust fan 5-5, and a circulating pump 5-6; all of which are equipped with material inlets and material outlets.

[0058] The exhaust system 6 includes a chimney for discharging deeply purified exhaust gas.

[0059] The exhaust gas outlet of the first filter 2-1 is connected to one of the exhaust gas inlets of the primary spray tower 3-1.

[0060] The exhaust gas outlet of the second filter 2-2 is connected to the material inlet of the first adsorption fan 5-1.

[0061] The purified gas outlet of the primary activated carbon fiber adsorption box 3-2 is connected to the material inlet of the first adsorption fan 5-1.

[0062] The material outlet of the first adsorption fan 5-1 is connected to the exhaust gas inlet of the secondary molecular sieve rotary adsorption box 3-3.

[0063] In some instances, the purified gas outlet of the primary activated carbon fiber adsorption box 3-2 is combined with the exhaust gas discharged from the exhaust gas outlet of the second filter 2-2 via a pipeline before the material inlet of the first adsorption fan 5-1. The combined exhaust gas is then connected to the exhaust gas inlet of the secondary molecular sieve rotor adsorption box 3-3 via the material outlet of the first adsorption fan 5-1.

[0064] The purified gas outlet of the secondary molecular sieve rotary adsorption box 3-3 is connected to the waste gas inlet of the tertiary fixed bed adsorption box 3-4.

[0065] The exhaust gas outlet of the third filter 2-3 is connected to the exhaust gas inlet of the three-stage fixed bed adsorption box 3-4;

[0066] In some instances, the exhaust gas outlet of the third filter 2-3 is combined with the purified gas outlet of the secondary molecular sieve rotary adsorption box 3-3, and the combined exhaust gas enters the exhaust gas inlet of the tertiary fixed bed adsorption box 3-4.

[0067] The purified gas outlet of the three-stage fixed bed adsorption box 3-4 is connected to the material inlet of the second adsorption fan 5-2; the first material outlet of the second adsorption fan 5-2 is connected to the exhaust system 6 (e.g., a chimney), and the deeply purified exhaust gas is directly discharged into the air;

[0068] The high-temperature steam outlet of the low-NOx combustion boiler 4-4 is connected to the high-temperature steam inlet of the third heat exchanger 4-3.

[0069] The high-temperature steam outlet of the third heat exchanger 4-3 is connected to the steam inlet of the first-stage activated carbon fiber adsorption box 3-2; the waste gas desorbed from the third-stage fixed bed adsorption box 3-4 exchanges heat with the high-temperature steam discharged from the third heat exchanger 4-3; the steam after heat exchange enters the first-stage activated carbon fiber adsorption box 3-2.

[0070] In some examples, the high-temperature steam generated by the low-NOx combustion boiler 4-4 enters through the high-temperature steam inlet of the third heat exchanger 4-3, where it exchanges with a portion of the clean gas drawn from the second adsorption fan 5-2. This clean gas is used as the desorption gas required for the desorption stage. After heat exchange with the second heat exchanger 4-2 and the first heat exchanger 4-1, it enters the third heat exchanger 4-3 for further heat exchange. The steam after heat exchange enters through the steam inlet of the primary activated carbon fiber adsorption box 3-2. The clean gas drawn from the second adsorption fan 5-2, after heat exchange, enters the desorption fans 5-3 and 5-4 for the next process.

[0071] The desorption gas outlet of the primary activated carbon fiber adsorption box 3-2 is connected to the concentrated gas inlet of the first heat exchanger 4-1; the concentrated gas outlet of the first heat exchanger 4-1 is connected to the condensate concentrated gas inlet of the condensation recovery device 3-5; the condensate concentrated gas outlet of the condensation recovery device 3-5 is connected to the condensate concentrated gas inlet of the gas-liquid separator 3-6; the recovered solvent outlet of the gas-liquid separator 3-6 is connected to the solvent inlet of the recovered solvent 3-7; and the solvent outlet of the recovered solvent storage tank 3-7 is matched with the raw materials required for production.

[0072] The non-condensable gas outlet of the gas-liquid separator 3-6 is connected to the non-condensable gas inlet of the dehumidifier 2-4; the non-value gas discharge outlet of the gas-liquid separator 3-6 is connected to the material inlet of the exhaust fan 5-5; the outlet of the exhaust fan 5-5 is connected to the exhaust gas inlet of the low-NOx combustion boiler 4-4; natural gas and deionized water enter the low-NOx combustion boiler 4-4.

[0073] The purified gas drawn out from the second material outlet of the second adsorption fan 5-2 can be used as the desorption gas for the secondary molecular sieve rotary adsorption box 3-3 and the tertiary fixed bed adsorption box 3-4.

[0074] The second material outlet of the second adsorption fan 5-2 is connected to the purified gas inlet of the second heat exchanger 4-2; the purified gas outlet of the second heat exchanger 4-2 is connected to the purified gas inlet of the first heat exchanger 4-1; the purified gas outlet of the first heat exchanger 4-1 is connected to the purified gas inlet of the third heat exchanger 4-3; and the purified gas outlet of the third heat exchanger 4-3 is connected to the material inlet of the first desorption fan 5-3 and the material inlet of the second desorption fan 5-4, respectively.

[0075] The material outlet of the first desorption blower 5-3 is connected to the hot air inlet of the secondary molecular sieve rotor adsorption box 3-3; the desorption gas outlet of the secondary molecular sieve rotor adsorption box 3-3 is connected to the exhaust gas inlet of the spray tower 3-1.

[0076] The material outlet of the second desorption fan 5-4 is connected to the hot air inlet of the three-stage fixed bed adsorption box 3-4; the desorption gas outlet of the three-stage fixed bed adsorption box 3-4 is connected to the concentrated gas inlet of the second heat exchanger 4-2; and the concentrated gas outlet of the second heat exchanger 4-2 is connected to another waste gas inlet of the spray tower 3-1.

[0077] The circulating pump 5-6 has at least two material outlets and at least one material inlet. One outlet is connected to the circulating spray liquid inlet (located at the top) of the primary spray tower 3-1; the other outlet is connected to the solvent inlet of the recovered solvent storage tank 3-7; and the inlet of the circulating pump 5-6 is connected to the circulating spray liquid outlet (located at the bottom) of the spray tower 3-1.

[0078] like Figure 1 As shown, in some embodiments, the textile coating organic waste gas staged deep treatment device further includes an intelligent monitoring system 7. The intelligent monitoring system 7 includes: an air volume monitoring device, a non-methane total hydrocarbon concentration monitoring device, an oxygen concentration monitoring device, a pressure monitoring device, a power equipment operation status monitoring device, a power consumption monitoring device, a carbon emission data analysis and programmable logic controller (PLC) control system, which can be added or removed according to the monitoring points. The intelligent monitoring system 7 controls other systems of the volatile organic waste gas staged deep treatment device of the present invention (i.e., volatile organic waste gas system 1, pretreatment system 2, staged adsorption and recovery system 3, heat comprehensive utilization system 4, power system 5, and exhaust system 6).

[0079] In some embodiments, the filter is one or a combination of two or more of the following: wet scrubber, dry filter, electrostatic precipitator, and gravity scrubber.

[0080] In some embodiments, the primary spray tower has a spray liquid consisting of one or more of deionized water, distilled water, and high-boiling-point organic solvents.

[0081] In some embodiments, the adsorbent material in the three-stage fixed-bed adsorption box is one of hydrophobic molecular sieves, modified zeolite, and activated carbon; the adsorbent material is in the form of granular, honeycomb, or corrugated plate.

[0082] In some embodiments, the low-NOx combustion boiler uses a natural gas-type low-NOx burner. The NOx emission level can be selected to be below 30 mg / Nm³. 3 Low-NOx burner.

[0083] The low-NOx combustion boiler mainly uses natural gas combustion to generate high-temperature steam, providing heat for the entire system.

[0084] In some embodiments, the non-methane total hydrocarbon concentration at the exhaust gas inlet of the primary activated carbon fiber adsorption box is 1000-5000 mg / Nm³. 3 After adsorption and purification, the concentration of non-methane total hydrocarbons at the outlet is 100-500 mg / Nm³. 3 Its purification efficiency is controlled at 90-95%.

[0085] In some embodiments, the non-methane total hydrocarbon concentration at the exhaust gas inlet of the secondary molecular sieve rotor adsorption box is 100-500 mg / Nm³. 3 After adsorption and purification, the concentration of non-methane total hydrocarbons at the outlet is 50-100 mg / Nm³. 3 Its purification efficiency is controlled at 80-90%.

[0086] In some embodiments, the non-methane total hydrocarbon concentration at the exhaust gas inlet of the three-stage fixed-bed adsorption box is 50-100 mg / Nm³. 3 After adsorption and purification, the concentration of non-methane total hydrocarbons at the final emission outlet is less than 20 mg / Nm³. 3 Its purification efficiency is controlled at 80-90%.

[0087] In some embodiments, the organic waste gas, calculated as non-methane total hydrocarbons, has a high concentration of organic waste gas greater than 1000-5000 mg / Nm³. 3 And less than 25% of the lower explosive limit of its exhaust gas components; the concentration of medium and low concentration organic waste gas is 100-500 mg / Nm³. 3 Low-concentration organic waste gas concentration is less than 100 mg / Nm³. 3 .

[0088] Specifically, the connection relationships of the above-mentioned textile coating organic waste gas staged deep treatment device are as follows:

[0089] High-concentration organic waste gas is collected by the first gas collection hood 1-1, and connected to the inlet of the first filter 2-1 of the pretreatment device through a pipeline. The outlet of the first filter 2-1 is connected to the waste gas inlet of the primary spray tower 3-1. The waste gas outlet of the primary spray tower 3-1 is connected to the waste gas inlet of the dehumidifier 2-4. The waste gas outlet of the dehumidifier 2-4 is connected to the waste gas inlet of the primary activated carbon fiber adsorption box 3-2. The purified gas outlet of the primary activated carbon fiber adsorption box 3-2 is connected to the inlet of the first adsorption fan 5-1.

[0090] Low-to-medium concentration organic waste gas is collected by the second gas collection hood 1-2 and connected to the inlet of the second filter 2-2 of the pretreatment device through a pipeline. The outlet of the second filter 2-2 is connected to the inlet of the first adsorption fan 5-1. At the same time, the waste gas from the outlet of the primary activated carbon fiber adsorption box 3-2 is combined with the waste gas discharged from the outlet of the second filter 2-2 through a pipeline before the inlet of the first adsorption fan 5-1. The combined waste gas is connected to the waste gas inlet of the secondary molecular sieve rotor adsorption box 3-3 through the outlet of the first adsorption fan 5-1. The purified gas outlet of the secondary molecular sieve rotor adsorption box 3-3 is connected to the waste gas inlet of the tertiary fixed bed adsorption box 3-4.

[0091] Low-concentration organic waste gas is collected by the third gas collection hood 1-3, and its outlet is connected to the inlet of the third filter 2-3 of the pretreatment device through a pipeline. The outlet of the third filter 2-3 is connected to the waste gas inlet of the three-stage fixed bed adsorption box 3-4. At the same time, the waste gas from the outlet of the third filter 2-3 is combined with the purified gas outlet of the secondary molecular sieve rotary adsorption box 3-3. The combined waste gas enters the waste gas inlet of the three-stage fixed bed adsorption box 3-4. The purified gas outlet of the three-stage fixed bed adsorption box 3-3 is connected to the inlet of the second adsorption fan 5-2. The outlet of the second adsorption fan 5-2 is connected to the chimney 6. The deeply purified waste gas is directly discharged into the air.

[0092] The high-temperature steam enters through the high-temperature steam inlet of the third heat exchanger 4-3. After heat exchange, the steam enters through the steam inlet of the primary activated carbon fiber adsorption box 3-2. The desorbed gas outlet of the primary activated carbon fiber adsorption box 3-2 is connected to the concentrated gas inlet of the first heat exchanger 4-1. The concentrated gas outlet of the first heat exchanger 4-1 is connected to the condensate concentrated gas inlet of the condensation recovery device 3-5. The condensate concentrated gas outlet of the condensation recovery device 3-5 is connected to the condensate concentrated gas inlet of the gas-liquid separator 3-6. The gas outlet of the gas-liquid separator 3-6 is connected to the inlet of the recovered solvent 3-7. The solvent outlet of the recovered solvent storage tank 3-7 is matched with the raw materials required for production. The non-condensable gas outlet of the gas-liquid separator 3-6 is connected to the inlet of the dehumidifier 2-4. The non-value gas emission outlet of the gas-liquid separator 3-6 is connected to the inlet of the exhaust fan 5-5. The outlet of the exhaust fan 5-5 is connected to the inlet of the low-NOx combustion boiler 4-4, and simultaneously enters the low-NOx combustion boiler 4-4 along with natural gas.

[0093] The outlet of the second adsorption fan 5-2 leads out a portion of the purified gas, which can be used as the desorption gas for the secondary molecular sieve rotary adsorption box 3-3 and the tertiary fixed bed adsorption box 3-4. The outlet of the second adsorption fan 5-2 is connected to the purified gas inlet of the second heat exchanger 4-2; the purified gas outlet of the second heat exchanger 4-2 is connected to the purified gas inlet of the first heat exchanger 4-1; the purified gas outlet of the first heat exchanger 4-1 is connected to the purified gas inlet of the third heat exchanger 4-3; and the purified gas outlet of the third heat exchanger 4-3 is connected to the inlets of the first desorption fan 5-3 and the second desorption fan 5-4, respectively.

[0094] The outlet of the first desorption fan 5-3 is connected to the hot air inlet of the secondary molecular sieve rotor adsorption box 3-3; the desorption gas outlet of the secondary molecular sieve rotor adsorption box 3-3 is connected to the exhaust gas inlet of the spray tower 3-1.

[0095] The outlet of the second desorption fan 5-4 is connected to the hot air inlet of the three-stage fixed bed adsorption box 3-4; the desorption gas outlet of the three-stage fixed bed adsorption box 3-4 is connected to the concentrated gas inlet of the second heat exchanger 4-2; and the concentrated gas outlet of the second heat exchanger 4-2 is connected to the exhaust gas inlet of the spray tower 3-1.

[0096] The circulating pump 5-6 has two outlets and one inlet. One outlet is connected to the inlet of the circulating spray liquid at the top of the spray tower 3-1; the other outlet is connected to the inlet of the solvent recovery storage tank. The inlet of the circulating pump 5-6 is connected to the outlet of the circulating spray liquid at the bottom of the spray tower 3-1.

[0097] The present invention also provides a method for graded and in-depth treatment of organic waste gas from textile coatings, using the above-mentioned graded and in-depth treatment device for organic waste gas from textile coatings, the method comprising the following steps:

[0098] 1) Waste gas collection process: Collect high-concentration organic waste gas, medium-low concentration organic waste gas and low-concentration organic waste gas separately;

[0099] 2) Pretreatment process: High-concentration organic waste gas, medium-low concentration organic waste gas and low-concentration organic waste gas are respectively fed into the pretreatment system for treatment, so that the particulate matter, grease, paint mist and temperature of the waste gas meet the requirements of the downstream treatment process.

[0100] 3) Staged adsorption and purification process:

[0101] High-concentration volatile organic waste gas after pretreatment enters the spray tower. The spray liquid is selected based on the properties of the waste gas to be treated and the principle of similar compatibility, and primary recovery is carried out to reduce the concentration of the waste gas.

[0102] After primary spraying, the exhaust gas is dehumidified and then enters the primary activated carbon fiber adsorption box for adsorption and separation purification. Volatile organic components are adsorbed into the pores by the activated carbon fiber material, thus separating the organic components from the exhaust gas. The separated organic exhaust gas is initially purified.

[0103] The secondary molecular sieve rotary adsorption box collects two sources of waste gas: one part comes from the gas purified by the primary adsorption, and the other part comes from the pretreated waste gas with medium and low concentrations of organic waste gas. The combined organic waste gas enters the secondary molecular sieve rotary adsorption box for secondary adsorption purification. Volatile organic components are adsorbed into the pores by the molecular sieve material, realizing the further separation of organic components from the waste gas. The separated organic waste gas is purified again, and the concentration of organic matter in the waste gas is further reduced.

[0104] The three-stage fixed-bed adsorption box collects two sources of waste gas: one is the gas purified by the second-stage adsorption, and the other is the waste gas after pretreatment of low-concentration organic waste gas. The combined organic waste gas enters the three-stage fixed-bed adsorption box for three-stage purification. Volatile organic components are adsorbed into the pores by the adsorption material, realizing the further separation of organic components from the waste gas. The separated organic waste gas is deeply purified and can be directly discharged into the air through the chimney.

[0105] 4) Desorption and Concentration Process

[0106] When the gas obtained by multi-stage adsorption purification in the above-mentioned 3) staged adsorption purification process reaches the controlled purification efficiency and controlled concentration value, the purified gas is discharged from the outlet of the adsorption box. At the same time, the adsorption box enters the desorption and regeneration process, and the desorbed gas desorbs the organic matter in the adsorption material in the adsorption box at an appropriate temperature.

[0107] The high-concentration organic waste gas desorbed from the primary activated carbon fiber adsorption box is cooled by heat exchange and then enters the next step of condensation and recovery; the high-concentration organic waste gas desorbed from the hot air in the secondary and tertiary adsorption boxes is cooled by heat exchange and then returned to the primary spray tower, where it is combined with the pretreated high-concentration organic waste gas and continues to enter the primary activated carbon fiber adsorption box for purification, forming a cycle.

[0108] 5) Condensation recovery process

[0109] The primary activated carbon adsorption box is regenerated by high-temperature steam desorption, forming an organic solvent-water mixture. This mixture enters a heat exchanger for heat exchange, and then passes through a condensation recovery device for cooling and liquefaction, forming an organic solvent-water mixture. This mixture, along with non-condensable gas, enters a gas-liquid separator for separation, achieving the separation of organic solvent and water, as well as the separation of the mixture from the non-condensable gas. The separated organic solvent enters a solvent recovery storage tank, while the non-condensable gas enters a dehumidifier and then re-enters the primary activated carbon fiber adsorption box for circulating purification.

[0110] In some instances, 4) in the desorption and concentration process, the primary activated carbon fiber adsorption box is regenerated using high-temperature steam, while the secondary molecular sieve rotor adsorption box and the tertiary fixed bed adsorption box are regenerated using high-temperature air.

[0111] In some examples, the above-mentioned method for graded and in-depth treatment of organic waste gas from textile coatings also includes the following steps:

[0112] 6) Heating and incineration process of low-NOx combustion boiler

[0113] A natural gas-fired low-NOx boiler is used to provide the heat source required for desorption.

[0114] In some instances, low-NOx combustion boilers can provide the heat source required for desorption, including high-temperature steam and heat-exchanged hot air desorbed gas. In other instances, a portion of the waste gas with no recovery value can be directly incinerated in a low-NOx combustion boiler without undergoing a condensation and cooling stage. The treated waste gas is then discharged through a chimney.

[0115] In some instances, the aforementioned method for the graded and in-depth treatment of organic waste gas from textile coatings employs intelligent control. In specific examples, a PLC is used for control, managing the key parameters required by the system. This intelligent control includes, but is not limited to, monitoring of airflow, non-methane total hydrocarbon concentration, oxygen concentration, pressure, power equipment operating status, power consumption, and carbon emission data analysis.

[0116] In some specific examples, the method for graded and in-depth treatment of organic waste gas from textile coatings includes:

[0117] 1) Waste gas collection process

[0118] During operation, enterprises collect volatile organic compounds (VOCs) generated according to their operating conditions. The collection method utilizes a VOC system 1, which can be achieved through direct collection via process pipelines or by using a gas collection hood. VOCs of the same type are collected and aggregated at the emission outlet. The distinction between high-concentration, medium-to-low-concentration, and low-concentration VOCs is based on their source and concentration.

[0119] 2) Pretreatment process

[0120] Volatile organic waste gas enters the pretreatment system 2 for treatment, so that the particulate matter, grease, paint mist and temperature of the waste gas meet the requirements of the downstream treatment process.

[0121] 3) Staged adsorption and purification process

[0122] High-concentration volatile organic waste gas after pretreatment enters the spray tower. The spray liquid is selected based on the properties of the waste gas to be treated and the principle of similar compatibility, and primary recovery is carried out to reduce the concentration of the waste gas.

[0123] The concentration of exhaust gas after primary spraying is still high. After dehumidification, it enters the primary activated carbon fiber adsorption box for adsorption and separation purification. Volatile organic components are adsorbed into the pores by the activated carbon fiber material, realizing the separation of organic components from the exhaust gas. The separated organic exhaust gas is initially purified. Due to the control of the purification efficiency of the primary activated carbon fiber adsorption box, the gas purified by the primary activated carbon fiber does not meet the requirements for direct emission or deep treatment emission standards, and a second-stage adsorption purification is required.

[0124] The secondary molecular sieve rotor adsorption box collects two sources of waste gas: one from the gas purified by the primary adsorption stage, and the other from the pretreated waste gas containing low to medium concentration organic waste gas. The combined organic waste gas enters the secondary molecular sieve rotor adsorption box for secondary adsorption purification. Volatile organic components are adsorbed into the pores of the molecular sieve material, achieving further separation of organic components from the waste gas. The separated organic waste gas is then purified again, further reducing the concentration of organic matter in the waste gas. The purification efficiency of the secondary molecular sieve rotor adsorption box is also controlled. To achieve the goal of deep purification, the gas purified by the secondary adsorption stage needs to undergo tertiary adsorption purification.

[0125] The three-stage fixed-bed adsorption box collects two sources of waste gas: one part comes from the gas purified by the second-stage adsorption, and the other part comes from the pretreated waste gas of low-concentration organic waste gas. The combined organic waste gas enters the three-stage fixed-bed adsorption box for three-stage purification. Volatile organic components are adsorbed into the pores by the adsorption material, realizing the further separation of organic components from the waste gas. The separated organic waste gas is deeply purified and can be directly discharged into the air through the chimney.

[0126] 4) Desorption and Concentration Process

[0127] When the gas obtained from the multi-stage adsorption purification in step 3) above reaches the controlled purification efficiency and concentration value, the purified gas is discharged from the outlet of the adsorption box. Simultaneously, the adsorption box enters the desorption and regeneration process, where the desorbed gas desorbs the organic matter adsorbed in the adsorption material within the adsorption box at an appropriate temperature. Specifically, the primary activated carbon fiber adsorption box uses high-temperature steam for regeneration, while the secondary molecular sieve rotor adsorption box and the tertiary fixed-bed adsorption box use high-temperature air for regeneration. The high-concentration organic waste gas desorbed from the primary activated carbon fiber adsorption box undergoes heat exchange and cooling before entering the next step of condensation and recovery. Meanwhile, the high-concentration organic waste gas desorbed from the secondary and tertiary adsorption boxes returns to the primary spray tower after heat exchange and cooling, where it merges with the pretreated high-concentration organic waste gas and continues to enter the primary activated carbon fiber adsorption box for purification, forming a cycle.

[0128] 5) Condensation recovery process

[0129] The primary activated carbon adsorption box is regenerated using high-temperature steam desorption, resulting in an organic solvent-water mixture. This mixture enters a heat exchanger for heat exchange, and then is cooled and liquefied by a condensation recovery device to form an organic solvent-water mixture. This mixture, along with non-condensable gas, enters a gas-liquid separator for separation, achieving the separation of organic solvent and water, and the separation of the mixture from the non-condensable gas. The separated organic solvent enters a solvent recovery storage tank. The non-condensable gas, after entering a dehumidifier, re-enters the primary activated carbon fiber adsorption box for continuous purification.

[0130] 6) Heating and incineration process of low-NOx combustion boiler

[0131] A natural gas-fired low-NOx combustion boiler is used. On the one hand, the boiler provides the heat source required for desorption, such as high-temperature steam and desorbed hot air after heat exchange. On the other hand, some waste gases without recovery value can be directly incinerated in the low-NOx combustion boiler without going through a condensation and cooling stage. The waste gas after combustion is discharged through a chimney.

[0132] 7) Intelligent control process

[0133] The control system of this invention uses a PLC for control, controlling the key parameters required by the system. Its intelligent monitoring includes, but is not limited to, air volume monitoring, non-methane total hydrocarbon concentration monitoring, oxygen concentration monitoring, pressure monitoring, power equipment operating status monitoring, power consumption monitoring, and carbon emission data analysis.

[0134] The aforementioned activated carbon fiber adsorption box, molecular sieve rotor adsorption box, and fixed bed adsorption box can be equipped with at least one adsorption box according to the operating conditions required for treating organic waste gas. They can be operated via an intelligent control system, and the device can operate intermittently or continuously. When multiple boxes are used, automatic switching is performed based on waste gas purification efficiency and emission concentration, all of which can be controlled autonomously by the intelligent control system. When necessary, the intelligent control system also includes manual control to improve its flexibility, safety, and convenience.

[0135] Taking the textile dyeing and finishing industry as an example, the production process of coated fabrics mainly uses coating agents (coating finishing agents or coating adhesives) and their related auxiliaries and solvents. The volatile organic compounds (VOCs) mainly come from the evaporation of the coating agent's solvent. Solvent-based coatings primarily generate organic waste gases such as toluene, N,N-dimethylformamide (DMF), and methyl ethyl ketone (MEK), with large emissions and high concentrations. Water-based coatings mostly use polyacrylate adhesives, mainly generating small amounts of VOCs such as acrylic acid, methyl acrylate, ethyl acrylate, and butyl acrylate, with relatively low emission concentrations. In addition, there are PVC, silicone, and synthetic rubber coatings, which mainly generate particulate matter (oil fumes and aerosols) waste gases. The coating process flow and main pollution-generating stages are as follows: Figure 3 As shown. The following are methods for graded and in-depth treatment of organic waste gas:

[0136] 1) Collection

[0137] Based on the operating conditions of waste gas generation, the generated volatile organic compounds (VOCs) are collected separately. Collection methods include direct collection via process pipelines or collection hoods. Waste gases of the same type are collected and aggregated before being discharged to the waste gas outlet. High-concentration organic waste gases have a non-methane total hydrocarbon concentration of 1000-5000 mg / Nm³. 3 Based on the operating conditions, a first gas collection hood 1-1 and a waste gas collection and summing outlet were installed; the concentration of non-methane total hydrocarbons in the low-to-medium concentration organic waste gas is 100-500 mg / Nm³. 3 A second gas collection hood 1-2 and a waste gas collection and summing outlet were installed according to the operating conditions; the concentration of non-methane total hydrocarbons in the low-concentration organic waste gas is 50-100 mg / Nm³. 3 According to the working conditions, the third gas collection hood 1-3 and the exhaust gas collection and summing outlet were set up;

[0138] The solvent evaporation from the coating agent is a major contributor to the generation of organic waste gases, such as toluene, N,N-dimethylformamide (DMF), and methyl ethyl ketone. These gases are emitted in large quantities and at high concentrations, and can be classified as high-concentration organic waste gases.

[0139] Water-based coatings mostly use polyacrylate adhesives, which mainly produce small amounts of VOCs such as acrylic acid, methyl acrylate, ethyl acrylate, and butyl acrylate. The emission concentration is relatively low and can be labeled as low to medium concentration organic waste gas.

[0140] Gases collected from material storage rooms, hazardous waste storage rooms, and fugitive emissions can be labeled as low-concentration organic waste gases.

[0141] 2) Pretreatment

[0142] Volatile organic waste gases of different concentrations enter the pretreatment device for treatment, so that the particulate matter, grease, paint mist and temperature of the waste gas meet the requirements of the downstream treatment process.

[0143] Among them, the high-concentration organic waste gas is collected at the outlet of the first gas collection hood 1-1 and enters the first filter 2-1 of the pretreatment device through the pipeline. After the filter is purified to remove particulate matter, oil fumes and other impurities, the waste gas after pretreatment enters the graded adsorption purification process.

[0144] The low-to-medium concentration organic waste gas is collected at the outlet of the second gas collection hood 1-2 and enters the second filter 2-2 of the pretreatment device through a pipeline. After being purified by the filter, impurities such as particulate matter and oil fumes are removed. The pretreated waste gas then enters the staged adsorption purification process.

[0145] The low-concentration organic waste gas from the third gas collection hood 1-3 outlet enters the third filter 2-3 of the pretreatment device through a pipeline. After being purified by the filter to remove particulate matter, oil fumes and other impurities, the pretreated waste gas enters the graded adsorption purification process.

[0146] 3) Staged adsorption and purification

[0147] Primary adsorption purification: The pretreated high-concentration volatile organic waste gas enters the spray tower 3-1 through the first gas collection hood 1-1. The spray liquid is selected according to the properties of the waste gas to be treated and the principle of similar compatibility, and primary recovery is carried out to reduce the concentration of the waste gas.

[0148] The concentration of exhaust gas remains high after primary spraying. After dehumidifier 2-4 removes the solution from the exhaust gas, it enters the primary activated carbon fiber adsorption box 3-2 for adsorption and separation purification. Volatile organic components are adsorbed into the pores by the activated carbon fiber material, thus separating the organic components from the exhaust gas. The separated organic exhaust gas is initially purified. Since the purification efficiency of the primary activated carbon fiber adsorption box is controlled at 90%-95%, the gas purified by the primary activated carbon fiber does not meet the requirements for direct emission or deep treatment emission standards, and a secondary adsorption purification step is required. The switching cycle of the activated carbon fiber adsorption box can be reasonably adjusted according to the exhaust gas conditions, and its control parameters can be completed by an intelligent monitoring system.

[0149] The secondary molecular sieve rotor adsorption box collects two sources of waste gas: one source is the gas purified by primary adsorption, and the other source is the pre-treated waste gas from low-to-medium concentration organic waste gas that enters the second filter 2-2 after passing through the second gas collection hood 1-2. The combined organic waste gas then enters the secondary molecular sieve rotor adsorption box 3-3 for secondary adsorption purification. Volatile organic components are adsorbed into the pores by the molecular sieve material, achieving further separation of organic components from the waste gas. The separated organic waste gas is then purified again, further reducing the concentration of organic matter in the waste gas. The purification efficiency of the secondary molecular sieve rotor adsorption box is controlled at 80%-90%. To achieve the goal of deep purification, the gas after secondary adsorption purification needs to undergo tertiary adsorption purification. The rotation speed of the molecular sieve rotor can be reasonably adjusted according to the waste gas conditions, and its control parameters can be completed by an intelligent monitoring system.

[0150] The three-stage fixed-bed adsorption box collects two sources of waste gas: one from the gas purified by the second-stage adsorption, and the other from the pre-treated waste gas that enters the third filter 2-3 after passing through the third gas collection hood 1-3. The combined organic waste gas then enters the three-stage fixed-bed adsorption box 3-4 for tertiary purification. Volatile organic components are adsorbed into the pores by the adsorption material, achieving further separation of the organic components from the waste gas. The separated organic waste gas is deeply purified and can be directly discharged through a chimney. The purification efficiency of the three-stage fixed-bed adsorption box is controlled at 80%-90%. Hydrophobic molecular sieves, modified zeolites, and activated carbon are preferred adsorption materials, with hydrophobic molecular sieves being the preferred choice. These molecular sieves have a dynamic water adsorption capacity of less than 5%, a silica-alumina ratio greater than 300, and a specific surface area greater than 350 m². 2 / g. Based on the three-level purification efficiency control, the deep treatment emission concentration is mainly for the textile dyeing and finishing industry. In some local standards, the limit for non-methane total hydrocarbon emission concentration is 60 mg / Nm³. 3 In this embodiment, the emission concentration limit for non-methane total hydrocarbons can be set at no higher than 20 mg / Nm³. 3 .

[0151] 4) Desorption and Concentration

[0152] When the gas obtained through multi-stage adsorption purification in step 3) above reaches the controlled purification efficiency and concentration value, the purified gas is discharged from the outlet of the adsorption box. At the same time, the adsorption box enters the desorption and regeneration process, where the desorbed gas desorbs the organic matter adsorbed in the adsorption material in the adsorption box at an appropriate temperature. Specifically, the primary activated carbon fiber adsorption box is regenerated using high-temperature steam, while the secondary molecular sieve rotor adsorption box and the tertiary fixed bed adsorption box are regenerated using high-temperature air.

[0153] The primary activated carbon fiber adsorption box is regenerated; high-temperature steam is generated by the low-NOx combustion boiler 4-4 and enters through the high-temperature steam inlet of the third heat exchanger 4-3. After heat exchange, the steam enters through the steam inlet of the primary activated carbon fiber adsorption box 3-2. The high-temperature steam regenerates the activated carbon fiber material and connects the desorption gas outlet of 3-4 to the concentrated gas inlet of the second heat exchanger 4-2 to cool the hot gas and preheat the cold air required for desorption in the secondary and tertiary adsorption devices.

[0154] After passing through the concentrated gas outlet of the first heat exchanger 4-1, the concentrated gas enters the condensation recovery device 3-5 for condensation recovery.

[0155] The high-concentration organic waste gas desorbed from the hot air in the secondary and tertiary adsorption boxes is cooled by heat exchange and returned to the primary spray tower 3-1. Then it is combined with the pretreated high-concentration organic waste gas in the spray tower and continues to enter the primary activated carbon fiber adsorption box for purification, forming a cycle.

[0156] 5) Condensation recovery

[0157] The primary activated carbon adsorption box is regenerated using high-temperature steam desorption. The desorption produces an organic solvent-water mixture, which enters the first heat exchanger 4-1 for heat exchange. After passing through the condensation recovery device 3-5, it is cooled and liquefied to form an organic solvent-water mixture. This mixture, along with non-condensable gas, enters the gas-liquid separator 3-6 for separation, achieving the separation of organic solvent and water, and the separation of the mixture from the non-condensable gas. The separated organic solvent enters the solvent recovery storage tank 3-7. The non-condensable gas enters the dehumidifier 2-4 and then re-enters the primary activated carbon fiber adsorption box 3-2 for further purification.

[0158] 6) Heating and incineration using low-NOx combustion boilers

[0159] A natural gas-fired low-NOx boiler (4-4) is used. On one hand, the boiler provides the heat source needed for desorption, such as high-temperature steam and desorbed hot air after heat exchange. On the other hand, some waste gas with no recovery value can be extracted by exhaust fan (5-5) and directly fed into the low-NOx boiler for incineration. The treated waste gas is then discharged through the chimney. It uses a low-NOx burner, and the NOx content in the waste gas in the chimney does not exceed 30 mg / Nm³. 3 .

[0160] 7) Intelligent Control System

[0161] The control system of this invention uses a PLC for control, controlling the key parameters required by the system. Its intelligent monitoring includes, but is not limited to, air volume monitoring, non-methane total hydrocarbon concentration monitoring, oxygen concentration monitoring, pressure monitoring, power equipment operating status monitoring, power consumption monitoring, and a carbon emission data analysis system.

[0162] Although the present invention has been described in detail above with general descriptions and specific embodiments, modifications or improvements can be made to it, which will be obvious to those skilled in the art. Therefore, all such modifications or improvements made without departing from the spirit of the present invention fall within the scope of protection claimed by the present invention.

Claims

1. A graded deep treatment device for organic waste gas from textile coatings, characterized in that, include: The system comprises a volatile organic compound (VOC) waste gas system, a pretreatment system, a staged adsorption and recovery system, a heat utilization system, a power system, and an exhaust system. The VOC waste gas system is connected sequentially to the pretreatment system, the staged recovery system, and the exhaust system via pipelines. The power system provides power to the VOC waste gas system. The heat utilization system provides heat to the staged deep treatment device for organic waste gas. The volatile organic compound (VOC) waste gas system includes: a first gas collection hood for recovering 1000-5000 mg / Nm³ of VOCs. 3 High-concentration organic waste gas; a second gas collection hood is used to recover 100-500 mg / Nm³ of organic waste gas. 3 Low to medium concentration organic waste gas; the third gas collection hood is used to recover less than 100 mg / Nm³. 3 Low concentration of organic waste gas; The pretreatment system includes: a first filter, a second filter, a third filter, and a dehumidifier; the exhaust gas inlet of the first filter is connected to the exhaust gas outlet of the first gas collection hood; the exhaust gas inlet of the second filter is connected to the exhaust gas outlet of the second gas collection hood; the exhaust gas inlet of the third filter is connected to the exhaust gas outlet of the third gas collection hood; the dehumidifier is also provided with a non-condensable gas inlet; The graded adsorption and recovery system includes: a primary spray tower, a primary activated carbon fiber adsorption box, a secondary molecular sieve rotor adsorption box, a tertiary fixed bed adsorption box, a condensation and recovery device, a gas-liquid separator, and a recovered solvent storage tank. The comprehensive heat utilization system includes: a first heat exchanger, a second heat exchanger, a third heat exchanger, and a low-NOx combustion boiler. The power system includes: a first adsorption fan, a second adsorption fan, a first desorption fan, a second desorption fan, an exhaust fan, and a circulation pump; The exhaust system includes a chimney; The waste gas treatment path within the device is configured as follows: the high-concentration organic waste gas enters the primary spray tower and dehumidifier after passing through the first gas collection hood and the first filter, and then enters the primary activated carbon fiber adsorption box for primary purification; the gas purified by the primary activated carbon fiber adsorption box is combined with the medium- and low-concentration organic waste gas pretreated by the second gas collection hood and the second filter, and then enters the secondary molecular sieve rotor adsorption box for secondary purification; the gas purified by the secondary molecular sieve rotor adsorption box is combined with the low-concentration organic waste gas pretreated by the third gas collection hood and the third filter, and then enters the tertiary fixed bed adsorption box for tertiary deep purification; the purified gas is then discharged through the exhaust system. The high-concentration organic waste gas generated by desorption in the secondary and tertiary adsorption boxes is returned to the inlet of the primary spray tower.

2. The textile coating organic waste gas staged deep treatment device according to claim 1, characterized in that, The primary spray tower is provided with an exhaust gas outlet, a circulating spray liquid inlet, a circulating spray liquid outlet, and at least two exhaust gas inlets; one of the exhaust gas inlets is connected to the exhaust gas outlet of the first filter, and the exhaust gas outlet is connected to the exhaust gas inlet of the dehumidifier. The primary activated carbon fiber adsorption box is equipped with an exhaust gas inlet, a purified gas outlet, a high-temperature water vapor inlet, and a desorption gas outlet. Its exhaust gas inlet is connected to the exhaust gas outlet of the dehumidifier. The secondary molecular sieve rotor adsorption box is equipped with a waste gas inlet, a purified gas outlet, a hot air inlet, and a desorption gas outlet; The three-stage fixed bed adsorption box is equipped with a purified gas outlet, a hot air inlet, a desorbed gas outlet, and at least one or two waste gas inlets; The condensation recovery device is equipped with a condensation and concentration gas inlet and a condensation and concentration gas outlet. The gas-liquid separator is equipped with a condensate concentrate inlet, a non-condensable gas outlet, a recovered solvent outlet, and a valueless gas emission outlet. The solvent recovery storage tank is equipped with a solvent recovery inlet and a solvent recovery outlet.

3. The textile coating organic waste gas staged deep treatment device according to claim 2, characterized in that, The first heat exchanger is provided with a purified gas inlet, a purified gas outlet, a desorbed gas inlet, and a concentrated gas outlet; The second heat exchanger is provided with a purified gas inlet, a purified gas outlet, a concentrated gas inlet, and a concentrated gas outlet; The third heat exchanger is equipped with a high-temperature steam inlet, a high-temperature steam outlet, a purified gas inlet, and a purified gas outlet. The low-NOx combustion boiler is equipped with an exhaust gas inlet, a natural gas inlet, a deionized water inlet, a high-temperature steam outlet, and a post-combustion gas exhaust outlet.

4. The textile coating organic waste gas graded deep treatment device according to claim 3, characterized in that, The exhaust gas outlet of the first filter is connected to one of the exhaust gas inlets of the primary spray tower; The exhaust outlet of the second filter is connected to the material inlet of the first adsorption fan; The purified gas outlet of the primary activated carbon fiber adsorption box is connected to the material inlet of the first adsorption fan; The material outlet of the first adsorption blower is connected to the exhaust gas inlet of the secondary molecular sieve rotary adsorption box; The purified gas outlet of the secondary molecular sieve rotary adsorption box is connected to the exhaust gas inlet of the tertiary fixed bed adsorption box. The exhaust gas outlet of the third filter is connected to the exhaust gas inlet of the three-stage fixed bed adsorption box; The purified gas outlet of the three-stage fixed bed adsorption box is connected to the material inlet of the second adsorption fan; the first material outlet of the second adsorption fan is connected to the exhaust system, and the deeply purified waste gas is directly discharged into the air. The high-temperature steam outlet of the low-NOx combustion boiler is connected to the high-temperature steam inlet of the third heat exchanger. The high-temperature steam outlet of the third heat exchanger is connected to the steam inlet of the first-stage activated carbon fiber adsorption box; the waste gas desorbed from the third-stage fixed bed adsorption box exchanges heat with the high-temperature steam discharged from the third heat exchanger; the steam after heat exchange enters the first-stage activated carbon fiber adsorption box.

5. The textile coating organic waste gas graded deep treatment device according to claim 4, characterized in that, The purified gas outlet of the primary activated carbon fiber adsorption box is combined with the exhaust gas discharged from the exhaust gas outlet of the second filter through a pipeline before the material inlet of the first adsorption blower. The combined exhaust gas is then connected to the exhaust gas inlet of the secondary molecular sieve rotary adsorption box through the material outlet of the first adsorption blower. The exhaust gas outlet of the third filter is combined with the purified gas outlet of the secondary molecular sieve rotary adsorption box, and the combined exhaust gas enters the exhaust gas inlet of the tertiary fixed bed adsorption box. The high-temperature steam generated by the low-NOx combustion boiler enters through the high-temperature steam inlet of the third heat exchanger and is used as the desorption gas required for the desorption stage, along with a portion of the clean gas drawn from the second adsorption fan. After heat exchange with the second and first heat exchangers, the steam enters the third heat exchanger for further heat exchange. The steam after heat exchange enters through the steam inlet of the primary activated carbon fiber adsorption box. After heat exchange with a portion of the clean gas drawn from the second adsorption fan, the steam enters the desorption fan and the desorption fan for the next step.

6. The textile coating organic waste gas staged deep treatment device according to claim 5, characterized in that, The desorption gas outlet of the primary activated carbon fiber adsorption box is connected to the concentrated gas inlet of the first heat exchanger; the concentrated gas outlet of the first heat exchanger is connected to the condensate concentrated gas inlet of the condensation recovery device; the condensate concentrated gas outlet of the condensation recovery device is connected to the condensate concentrated gas inlet of the gas-liquid separator; the recovered solvent outlet of the gas-liquid separator is connected to the solvent inlet of the recovered solvent; the solvent outlet of the recovered solvent storage tank is matched with the raw materials required for production. The non-condensable gas outlet of the gas-liquid separator is connected to the non-condensable gas inlet of the dehumidifier; the non-value gas emission outlet of the gas-liquid separator is connected to the material inlet of the exhaust fan; the outlet of the exhaust fan is connected to the exhaust gas inlet of the low-NOx combustion boiler; natural gas and deionized water enter the low-NOx combustion boiler; The purified gas drawn out from the second material outlet of the second adsorption blower can be used as the desorption gas for the secondary molecular sieve rotary adsorption box and the tertiary fixed bed adsorption box. The second material outlet of the second adsorption fan is connected to the purified gas inlet of the second heat exchanger; the purified gas outlet of the second heat exchanger is connected to the purified gas inlet of the first heat exchanger; the purified gas outlet of the first heat exchanger is connected to the purified gas inlet of the third heat exchanger; and the purified gas outlet of the third heat exchanger is connected to the material inlet of the first desorption fan and the material inlet of the second desorption fan, respectively. The material outlet of the first desorption blower is connected to the hot air inlet of the secondary molecular sieve rotor adsorption box; the desorption gas outlet of the secondary molecular sieve rotor adsorption box is connected to the exhaust gas inlet of the spray tower. The material outlet of the second desorption blower is connected to the hot air inlet of the three-stage fixed bed adsorption box; the desorption gas outlet of the three-stage fixed bed adsorption box is connected to the concentrated gas inlet of the second heat exchanger; and the concentrated gas outlet of the second heat exchanger is connected to another exhaust gas inlet of the spray tower. The circulating pump has at least two material outlets and at least one material inlet. One outlet is connected to the circulating spray liquid inlet of the primary spray tower; the other outlet is connected to the solvent inlet of the recovered solvent storage tank; and the inlet of the circulating pump is connected to the circulating spray liquid outlet of the spray tower.

7. The textile coating organic waste gas staged deep treatment device according to claim 6, characterized in that, The textile coating organic waste gas staged deep treatment device also includes an intelligent monitoring system; the intelligent monitoring system includes: air volume monitoring device, non-methane total hydrocarbon concentration monitoring device, oxygen concentration monitoring device, pressure monitoring device, power equipment operation status monitoring device, power consumption monitoring device, carbon emission data analysis and programmable logic controller control system; the intelligent monitoring system controls the volatile organic waste gas system, pretreatment system, staged adsorption and recovery system, heat comprehensive utilization system, power system and exhaust system respectively.

8. The textile coating organic waste gas staged deep treatment device according to claim 7, characterized in that, The exhaust gas inlet of the primary activated carbon fiber adsorption box has a non-methane total hydrocarbon concentration of 1000-5000 mg / Nm³. 3 After adsorption and purification, the concentration of non-methane total hydrocarbons at the outlet is 100-500 mg / Nm³. 3 Its purification efficiency is controlled at 90-95%; The exhaust gas inlet of the secondary molecular sieve rotor adsorption box has a non-methane total hydrocarbon concentration of 100-500 mg / Nm³. 3 After adsorption and purification, the concentration of non-methane total hydrocarbons at the outlet is 50-100 mg / Nm³. 3 Its purification efficiency is controlled at 80-90%; The exhaust gas inlet of the three-stage fixed-bed adsorption box has a non-methane total hydrocarbon concentration of 50-100 mg / Nm³. 3 After adsorption and purification, the concentration of non-methane total hydrocarbons at the final emission outlet is less than 20 mg / Nm³. 3 Its purification efficiency is controlled at 80-90%.

9. The textile coating organic waste gas staged deep treatment device according to any one of claims 1-8, characterized in that, Based on non-methane total hydrocarbons, the high concentration of organic waste gas is less than 25% of the lower explosion limit of its waste gas components.

10. A method for graded and in-depth treatment of organic waste gas from textile coatings, characterized in that, The method using the textile coating organic waste gas graded deep treatment device according to any one of claims 1-9 includes the following steps: 1) Waste gas collection process: Collect high-concentration organic waste gas, medium-low concentration organic waste gas and low-concentration organic waste gas separately; 2) Pretreatment process: High-concentration organic waste gas, medium-low concentration organic waste gas and low-concentration organic waste gas are respectively fed into the pretreatment system for treatment, so that the particulate matter, grease, paint mist and temperature of the waste gas meet the requirements of the downstream treatment process. 3) Staged adsorption and purification process: High-concentration volatile organic waste gas after pretreatment enters the spray tower. The spray liquid is selected based on the properties of the waste gas to be treated and the principle of similar compatibility, and primary recovery is carried out to reduce the concentration of the waste gas. After primary spraying, the exhaust gas is dehumidified and then enters the primary activated carbon fiber adsorption box for adsorption and separation purification. Volatile organic components are adsorbed into the pores by the activated carbon fiber material, thus separating the organic components from the exhaust gas. The separated organic exhaust gas is initially purified. The secondary molecular sieve rotary adsorption box collects two sources of waste gas: one part comes from the gas purified by the primary adsorption, and the other part comes from the pretreated waste gas with medium and low concentrations of organic waste gas. The combined organic waste gas enters the secondary molecular sieve rotary adsorption box for secondary adsorption purification. Volatile organic components are adsorbed into the pores by the molecular sieve material, realizing the further separation of organic components from the waste gas. The separated organic waste gas is purified again, and the concentration of organic matter in the waste gas is further reduced. The three-stage fixed-bed adsorption box collects two sources of waste gas: one is the gas purified by the second-stage adsorption, and the other is the waste gas from the pre-treated low-concentration organic waste gas. The combined organic waste gas enters the three-stage fixed-bed adsorption box for three-stage purification. Volatile organic components are adsorbed into the pores by the adsorption material, achieving further separation of organic components from the waste gas. The separated organic waste gas is deeply purified and can be directly discharged into the atmosphere through a chimney. The adsorbent in the fixed-bed adsorption box is a hydrophobic molecular sieve. 4) Desorption and Concentration Process When the gas obtained by multi-stage adsorption purification in the above-mentioned 3) graded adsorption purification process reaches the controlled purification efficiency and controlled concentration value, the purified gas is discharged from the outlet of the adsorption box. At the same time, the adsorption box enters the desorption regeneration process, and the desorbed gas desorbs the organic matter in the adsorption material in the adsorption box at an appropriate temperature. The high-concentration organic waste gas desorbed from the primary activated carbon fiber adsorption box is cooled by heat exchange and then enters the next step of condensation and recovery; the high-concentration organic waste gas desorbed from the hot air in the secondary and tertiary adsorption boxes is cooled by heat exchange and then returned to the primary spray tower, where it is combined with the pretreated high-concentration organic waste gas and continues to enter the primary activated carbon fiber adsorption box for purification, forming a cycle. 5) Condensation recovery process The primary activated carbon adsorption box is regenerated by high-temperature steam desorption, forming an organic solvent-water mixture. This mixture enters a heat exchanger for heat exchange, and then passes through a condensation recovery device for cooling and liquefaction, forming an organic solvent-water mixture. This mixture, along with non-condensable gas, enters a gas-liquid separator for separation, achieving the separation of organic solvent and water, as well as the separation of the mixture from the non-condensable gas. The separated organic solvent enters a solvent recovery storage tank, while the non-condensable gas enters a dehumidifier and then re-enters the primary activated carbon fiber adsorption box for circulating purification.

11. The method for graded and in-depth treatment of organic waste gas from textile coatings according to claim 10, characterized in that, It also includes the following steps: 6) Low-NOx combustion boiler heating and incineration process A natural gas-fired low-NOx boiler is used to provide the heat source required for desorption.

12. The method for graded and in-depth treatment of organic waste gas from textile coatings according to claim 10 or 11, characterized in that, The method for graded and in-depth treatment of organic waste gas from textile coatings employs intelligent control.

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