A highly efficient organic waste gas recovery device and process

Abstract

The present invention provides an organic waste gas recovery device and process, belonging to the technical field of organic waste gas treatment. It includes a condensation system, a membrane separation system, an adsorption system, and a vacuum system, wherein the vacuum system includes a vacuum pump 1 and a vacuum pump 2 that operate independently, wherein the inlet and outlet of the vacuum pump 1 are respectively connected to the membrane separation system and the condensation system, and the organic gas separated in the membrane separation system is circulated back to the condensation system by the vacuum pump 1; the inlet and outlet of the vacuum pump 2 are respectively connected to the adsorption system and the condensation system; the organic gas desorbed in the adsorption system is circulated back to the condensation system by the vacuum pump 2. In the present invention, the membrane separation system and the adsorption system are respectively separated by independent vacuum pumps to separate organic gas and air and desorb organic matter. In this way, the two systems do not interfere with each other, and the intermittent vacuum operation of the adsorption system will not affect the continuous vacuum operation of the membrane separation system, which effectively ensures the working stability of the membrane separation system.

Description

Technical Field

[0001] The present invention relates to the technical field of organic waste gas treatment, and in particular to an organic waste gas recovery device and process, which is particularly suitable for waste gas discharged in the production of petrochemical, fine chemical, spraying, medicine and pesticide manufacturing. Background Art

[0002] Volatile Organic Compounds (VOCs) are a common pollutant, and their main sources are the volatilization of organic solvents or exhaust emissions in the petrochemical, pharmaceutical, spraying and other industries. Most of the above-mentioned volatile organic compounds should be recycled because of their economic value; some of them are toxic and cannot be completely removed by other methods (such as incineration) or will cause secondary pollution after treatment, and cannot meet environmental protection requirements, so they can only be recycled. Commonly used recovery methods include adsorption, condensation and membrane separation.

[0003] For example, a Chinese patent discloses an organic waste gas recovery device and process based on membrane-coupled condensation adsorption, with application number CN201510982312.1. The recovery device includes a condensation system, a membrane separation system, an adsorption system, a vacuum system, and a product storage tank; wherein: the condensation system is used to condense organic waste gas to form a liquid organic solvent; the membrane separation system is connected to the condensation system and the adsorption system through pipelines; the adsorption system is used to adsorb organic waste gas; the vacuum system includes an inlet and an outlet, the inlet is connected to the membrane separation system and the adsorption system respectively, and the outlet is connected to the condensation system; the product storage tank is connected to the condensation system to store the organic solvent recovered by condensation. The recovery system combines the condensation system, the membrane separation system and the adsorption system to achieve better waste gas treatment results.

[0004] However, in this recovery system, the adsorption system uses vacuum desorption and regeneration. The membrane separation process and the desorption and regeneration process share a vacuum system, and the organic vapor extracted by vacuum is condensed again separately. However, the membrane separation process requires continuous vacuum operation, while the desorption and regeneration of the adsorption system is an intermittent vacuum operation. When the adsorption system is in desorption operation, the vacuum pressure borne by the membrane separation process will be unstable, and the separation effect of the membrane will gradually deteriorate. Incomplete desorption of organic matter for a long time will also damage the membrane, shortening the actual service life of the membrane. In addition, the adsorbent regeneration process of the adsorption system relies on vacuum desorption. The desorption efficiency of this desorption method is relatively low, and the complete desorption time is long. Incomplete desorption will make part of the adsorbent ineffective, reducing the adsorption efficiency of the adsorption system, and its overall treatment effect is limited. At the same time, the organic vapor extracted by vacuum is condensed again separately, and a condenser needs to be set up separately. The overall equipment is relatively complicated, and the tail gas after condensation is directly passed through the membrane separation system. The tail gas concentration received by the membrane separation system is unstable, and the separation effect of the membrane will also be affected.

[0005] In summary, the existing technology has problems such as slow recovery efficiency, easy damage of membrane and poor separation effect, which need to be improved. Summary of the invention

[0006] Based on the shortcomings of the prior art such as unstable membrane separation effect, fragile and short life of membrane devices, low organic waste gas treatment efficiency and complex devices, the present invention aims to provide a more efficient, more stable operation, longer service life and simpler equipment organic waste gas recovery device and process.

[0007] To achieve the above object, the present invention adopts the following technical solution:

[0008] An efficient organic waste gas recovery device comprises a condensation system, a membrane separation system, an adsorption system and a vacuum system, wherein the condensation system is used to condense organic tail gas to form a liquid organic solvent; the membrane separation system is connected to the condensation system and the adsorption system through pipelines; the adsorption system is used to adsorb organic tail gas; the tail gas to be treated passes through the condensation system, the membrane separation system and the adsorption system in sequence until it reaches the standard and is discharged;

[0009] The vacuum system includes a vacuum pump 1 and a vacuum pump 2 which operate independently, wherein the inlet and outlet of the vacuum pump 1 are connected to the membrane separation system and the condensation system respectively, and the organic gas separated in the membrane separation system is circulated back to the condensation system by the vacuum pump 1; the inlet and outlet of the vacuum pump 2 are connected to the adsorption system and the condensation system respectively; the organic gas desorbed in the adsorption system is circulated back to the condensation system by the vacuum pump 2.

[0010] Furthermore, the adsorption system is composed of two or more adsorption tanks connected in parallel, and adsorption fillers are arranged in the adsorption tanks. The adsorption system is connected with an adsorption air inlet pipeline, a vacuum desorption pipeline, and an exhaust pipeline. The untreated exhaust gas in the membrane separation system enters the adsorption tank along the adsorption air inlet pipeline, and the clean gas after adsorption treatment is discharged along the exhaust pipeline; the vacuum desorption pipeline is connected to vacuum pump 2; the adsorption system is also connected with a hot air inlet pipeline for introducing hot nitrogen or water vapor during the desorption operation.

[0011] Furthermore, a self-operated pressure reducing valve is also provided on the hot gas inlet pipeline.

[0012] Furthermore, the adsorption system is also connected to a cooling air inlet pipeline and a drying and cooling fan to introduce dry air after desorption is completed to cool and dry the adsorption filler in the adsorption tank.

[0013] Furthermore, the adsorption filler is one or more of the filler types including activated carbon, carbon fiber, macroporous resin, and molecular sieve.

[0014] Furthermore, the condensation system includes a buffer tank and a tail gas condenser, the inlet end of the buffer tank is connected to a first air inlet pipeline, a second air inlet pipeline and a third air inlet pipeline, wherein the first air inlet pipeline is used to transport the original tail gas to be treated, the second air inlet pipeline is used to transport the recovered tail gas enriched in the membrane separation system, and the third air inlet pipeline is used to transport the desorbed tail gas of the adsorption filler in the adsorption system; a first solvent recovery outlet is provided at the bottom of the buffer tank; a buffer tank gas outlet is also provided at the top of the buffer tank, which is connected to the tail gas condenser through a tail gas condensation pipeline.

[0015] Furthermore, the tail gas condenser is provided with a cooling medium inlet and a cooling medium outlet. The tail gas to be treated is condensed in the tail gas condenser and part of the solvent is recovered. A second solvent recovery outlet is provided at the bottom of the tail gas condenser, and a condenser gas outlet is also provided at the top of the tail gas condenser, which is connected to the membrane separation system through a membrane inlet pipeline.

[0016] Furthermore, the membrane separation system is composed of multiple membrane devices connected in series and / or in parallel; the membrane device includes a permeate side and a retentate side, wherein the permeate side is connected to a vacuum pump through a membrane recovery pipeline; the retentate side is connected to the adsorption system through an adsorption air inlet pipeline.

[0017] The present invention also provides an efficient organic waste gas recovery process, the recovery process comprising:

[0018] A. Buffer gas intake: the original tail gas to be treated, the recovered tail gas enriched after membrane separation, and the desorbed tail gas desorbed after adsorption enter the buffer tank through the first intake pipeline, the second intake pipeline, and the third intake pipeline respectively, and enter the tail gas condenser after merging in the buffer tank; part of the tail gas to be treated is naturally condensed in the buffer tank, and the recovered solvent liquid is regularly discharged from the first solvent recovery outlet;

[0019] B. Condensation recovery: The tail gas to be treated is condensed at low temperature in the tail gas condenser, the recovered organic solvent is discharged from the second solvent recovery outlet, and the uncondensed tail gas enters the membrane separation system from the membrane inlet pipeline;

[0020] C. Membrane separation: Uncondensed tail gas is separated by permeation in the membrane device of the membrane separation system. As long as the vacuum pump is in continuous operation, most of the organic gas enters the permeation side of the membrane device under the action of vacuum and membrane permeation, and the remaining gas enters the retentate side of the membrane device; the recovered tail gas enriched in the permeation side is circulated back to the buffer tank through the vacuum pump to merge with other gases and enter the B process; the organic waste gas on the retentate side enters the adsorption system through the adsorption air inlet pipeline;

[0021] D. Adsorption and emission: After the above-mentioned organic waste gas enters the adsorption tank of the adsorption system, the organic matter is adsorbed into the micropores of the adsorption filler. After adsorption, the organic waste gas is converted into clean gas, and the clean gas after adsorption treatment is discharged along the exhaust pipeline in compliance with the standards; after the adsorption filler is saturated with adsorption, the gas transmission adsorption is stopped, and the adsorption tank enters the next process; at the same time, the organic waste gas inlet of the adsorption tank is closed, and the organic waste gas enters other adsorption tanks to continue the adsorption operation; each adsorption tank is controlled by an automatic control system, and automatically switches to alternately perform the adsorption and regeneration processes, so that the adsorption system can operate continuously and treat the organic waste gas;

[0022] E. Desorption: The adsorbent filler after adsorption saturation is subjected to high-temperature and vacuum desorption regeneration. Specifically, the vacuum pump 2 is turned on, and hot nitrogen or water vapor with stable pressure is input into the adsorption tank through the hot gas inlet pipeline to desorb the organic matter adsorbed on the filler. At the same time, the mixed steam containing water vapor and organic vapor is blown out by the hot steam purge, and circulated back to the buffer tank through the vacuum pump 2 to merge with other gases and enter the B process; after the desorption of the adsorbent filler is completed, the vacuum valve of the adsorption tank is closed, and the adsorption tank enters the next process;

[0023] F. Cooling: The above-mentioned adsorption tank is cooled. Specifically, dry air is sent into the adsorption filler through a drying and cooling fan to purge the adsorption filler, thereby achieving the purpose of cooling and drying the adsorption filler. After purging, the gas is discharged through the exhaust pipeline. The adsorption tank after cooling and dehumidification resumes its adsorption function and is recycled.

[0024] Furthermore, in step F, at the initial stage of cooling, the air inlet of the drying and cooling fan is connected to the outlet of the exhaust pipeline. The dry air exhaust at this stage is in an internal circulation state until the exhaust gas detected at the exhaust pipeline meets the standard. The connection between the drying and cooling fan and the exhaust pipeline is disconnected, and air is naturally inhaled and exhausted until the adsorption tank drops to the normal operating temperature.

[0025] Compared with the prior art, the organic waste gas recovery device and process provided by the present invention have the following advantages:

[0026] 1. In the present invention, the membrane separation system and the adsorption system are respectively separated by independent vacuum pumps for separation of organic gas and air and desorption of organic matter. In this way, the two systems do not interfere with each other, and the intermittent vacuum operation of the adsorption system will not affect the continuous vacuum operation of the membrane separation system, which effectively ensures the working stability of the membrane separation system and protects the membrane. The membrane is more efficient, the separation effect of organic waste gas is better, and the service life of the membrane is effectively extended.

[0027] 2. In the present invention, in the desorption process of the adsorption filler, the organic matter adsorbed on the filler is desorbed by auxiliary input of hot nitrogen or steam, and at the same time, the mixed steam containing water vapor and organic vapor is blown out by steam purge, and the mixed steam containing water vapor and organic vapor is blown out and recovered back to the membrane system through the vacuum pump. Compared with vacuum desorption relying only on the vacuum pump, the desorption effect of the adsorption filler is better, which can effectively reduce the desorption time of the adsorption filler, improve the use efficiency of the adsorption filler, and then enhance the adsorption efficiency of the adsorption filler, and further improve the working efficiency of the entire organic waste gas recovery system. The adsorption tank of the adsorption system can be set according to the actual process quantity to achieve the effects of one absorption and one desorption, two absorptions and one desorption, three absorptions and one desorption, etc., which are controlled by the automatic control system and automatically switch to alternately perform the adsorption and regeneration processes, thereby ensuring the continuous operation and continuous processing capacity of the adsorption system.

[0028] 3. In the present invention, a drying and cooling fan is also added at the end of the adsorption system. When the desorption operation is completed, the adsorption filler has a very high temperature and a large amount of moisture, which is not conducive to the subsequent adsorption operation. The drying and cooling fan is set to introduce dry air to purge the adsorption filler to achieve the purpose of cooling and drying the adsorption filler. During the drying process, the water vapor after desorption and the organic matter remaining on the filler will be brought out, resulting in excessive emissions of dry tail gas for a short time. In order to ensure that the exhaust gas is always up to standard, the dry air exhaust is circulated internally to avoid the discharge of substandard gas in the initial stage of the dry air, to ensure that the entire exhaust gas treatment process is up to standard, and to reduce the pressure on environmental protection.

[0029] 4. In the present invention, the condensation system is composed of a buffer tank and a tail gas condenser. The original tail gas to be treated, the recovered tail gas enriched by the membrane, and the tail gas desorbed by the adsorption filler are firstly treated in the buffer tank. The buffer tank can separate the entrained liquid and remove the mechanical impurities that may be entrained. At the same time, it stabilizes the system and prevents the gases of different components from directly entering the post-installation device and influencing each other, so that the tail gas components finally entering the membrane separation system are relatively stable, which is conducive to the stable separation and treatment of organic waste gas by the membrane. The bottom of the buffer tank is regularly discharged to recover the solvent liquid, and the gas at the top of the buffer tank enters the tail gas condenser. Part of the solvent is recovered by the tail gas condenser to achieve solvent recovery. The buffer tank and the tail gas condenser are arranged at the front end of the membrane separation system, which can pre-recover the solvent to a greater extent, reduce the tail gas load entering the membrane, and then reduce the layout scale of the membrane device. This system is equivalent to setting only one condenser to meet the circulation recovery demand, and there is no need to set another condenser at the tail end of the adsorption system and the membrane separation system, which simplifies the device scale of the overall organic waste gas recovery system, simplifies the operation steps, and saves production costs.

[0030] In general, the organic waste gas recovery device and process provided by the present invention have a more reasonable arrangement of each subsystem, which not only improves the removal rate of organic gas in the organic waste gas tail gas, but also increases the treatment volume of tail gas per unit time, and the treatment efficiency is higher. At the same time, it also plays a certain protective role on the membrane and adsorption filler, prolongs their service life, has a higher application efficiency, and further reduces production costs. The organic waste gas recovery device and process can be applied to waste gas discharged in industries such as petrochemicals, fine chemicals, spraying, adhesive production, and pharmaceutical and pesticide manufacturing, and has a very wide range of applications. BRIEF DESCRIPTION OF THE DRAWINGS

[0031] Figure 1 Schematic diagram of an organic waste gas recovery device in an embodiment of the present invention.

[0032] Figure 2 Schematic diagram of the organic waste gas recovery process in the embodiment of the present invention.

[0033] In the figure, 1. condensation system; 11. buffer tank; 111. first air inlet pipeline; 112. second air inlet pipeline; 113. third air inlet pipeline; 114. first solvent recovery outlet; 115. tail gas condensation pipeline; 12. tail gas condenser; 121. cooling medium inlet; 122. cooling medium outlet; 123. second solvent recovery outlet; 124. condenser gas outlet; 2. membrane separation system; 21. membrane inlet pipeline; 22. membrane device; 221. permeate side; 222. retentate side; 23. membrane recovery pipeline; 3. adsorption system; 31. adsorption tank; 32. adsorption air inlet pipeline; 33. vacuum desorption pipeline; 34. exhaust pipeline; 35. hot air inlet pipeline; 36. cooling air inlet pipeline; 4. vacuum pump one; 5. vacuum pump two; 6. drying and cooling fan. DETAILED DESCRIPTION

[0034] The present invention will be described in detail below in conjunction with the various embodiments shown in the accompanying drawings. However, these embodiments do not limit the present invention, and any structural, methodological, or functional changes made by a person skilled in the art based on these embodiments are all within the scope of protection of the present invention.

[0035] The present invention discloses an organic waste gas recovery device, which can be applied to waste gas discharged from industries such as petrochemical, fine chemical, spraying, adhesive production, and medicine and pesticide manufacturing, such as Figure 1As shown, a highly efficient organic waste gas recovery device includes a condensation system 1, a membrane separation system 2, an adsorption system 3, and a vacuum system, characterized in that the condensation system 1 is used to condense organic tail gas to form a liquid organic solvent; the membrane separation system 2 is connected to the condensation system and the adsorption system through pipelines respectively; the adsorption system 3 is used to adsorb organic tail gas; the tail gas to be treated passes through the condensation system 1, the membrane separation system 2, and the adsorption system 3 in sequence until it reaches the standard and is discharged. In the present invention, the vacuum system includes a vacuum pump 1 4 and a vacuum pump 2 5 that operate independently, wherein the inlet and outlet of the vacuum pump 1 4 are connected to the membrane separation system 2 and the condensation system 1 respectively, and the organic gas separated from the membrane separation system 2 is circulated back to the condensation system 1 by the vacuum pump 1 4; the inlet and outlet of the vacuum pump 2 5 are connected to the adsorption system 3 and the condensation system 1 respectively; the organic gas desorbed from the adsorption system 3 is circulated back to the condensation system 1 by the vacuum pump 2 5.

[0036] In this embodiment, the tail gas to be treated includes the original tail gas to be treated, the recovered tail gas enriched in the membrane separation system 2, and the desorbed tail gas of the adsorption filler in the adsorption system 3. Among them, the original tail gas to be treated is the mixed tail gas of organic waste gas directly transported from the production workshop, which includes organic gas and air.

[0037] In this embodiment, the condensation system 1 includes a buffer tank 11 and a tail gas condenser 12 .

[0038] The inlet end of the buffer tank 11 is connected to the first air inlet line 111, the second air inlet line 112 and the third air inlet line 113, wherein the first air inlet line 111 is used to transport the original tail gas to be treated, the second air inlet line 112 is used to transport the recovered tail gas enriched in the membrane separation system 2, and the third air inlet line 113 is used to transport the desorbed tail gas of the adsorbed filler in the adsorption system 3; the bottom of the buffer tank 11 is provided with a first solvent recovery outlet 114, which regularly discharges the recovered solvent liquid; the top of the buffer tank 11 is also provided with a buffer tank gas outlet, which is connected to the tail gas condenser 12 through the tail gas condensation line 115. The second air inlet line 112 and the third air inlet line 113 can be connected through a three-way junction line to reduce the air inlet opening of the buffer tank 11 and reduce the sealing requirements of the buffer tank 11.

[0039] The tail gas condenser 12 is provided with a cooling medium inlet 121 and a cooling medium outlet 122. The tail gas to be treated is condensed in the tail gas condenser 12 to recover part of the solvent. A second solvent recovery outlet 123 is provided at the bottom. A condenser gas outlet 124 is also provided at the top of the tail gas condenser 12, which is connected to the membrane separation system 2 through the membrane inlet pipeline 21. Part of the solvent is recovered by condensing the existing cooling medium in the plant in the condenser to achieve solvent recovery, thereby reducing the membrane inlet tail gas load and thus reducing the scale of the membrane device.

[0040] The buffer tank 11 is at normal temperature and pressure, and the tail gas to be treated is mixed therein, and then enters the tail gas condenser 12 from the tail gas condensation pipeline 115. The gas is condensed at low temperature in the tail gas condenser 12, and the uncondensed tail gas enters the membrane separation system 2 from the membrane inlet pipeline 21.

[0041] In this embodiment, the membrane separation system 2 is composed of a plurality of membrane devices 22 connected in series and / or in parallel. In the figure, several membrane devices 22 are arranged in parallel, but they are actually arranged according to the specific processing scale. The uncondensed tail gas is separated by permeation in the membrane device 22. The membrane device 22 includes a permeate side 221 and a retentate side 222, wherein the permeate side 221 is connected to a vacuum pump 4 through a membrane recovery pipeline 23, and the enriched recovered tail gas is circulated back to the buffer tank 11 through a vacuum pump 4 to merge with the original tail gas to be treated; the retentate side 222 is connected to the adsorption system 3 through an adsorption air intake pipeline 32, and the waste gas after membrane treatment enters the adsorption system 3 through the adsorption air intake pipeline 32.

[0042] Since the gases have been buffered, mixed and filtered in the buffer tank 11, the membrane device 22 can be a common gas permeation membrane component without excessively high technical requirements.

[0043] In the prior art, for example, a Chinese patent discloses an organic waste gas recovery device and process based on membrane-coupled condensation adsorption, with the application number CN201510982312.1. In this recovery system, the adsorption system is desorbed by vacuum desorption and regeneration, and the membrane separation process and the desorption and regeneration process share a set of vacuum systems, and the organic vapor extracted by vacuum is condensed again separately. However, the membrane separation process requires continuous vacuum operation, while the desorption and regeneration of the adsorption system is an intermittent vacuum operation. When the adsorption system is in desorption operation, the vacuum pressure borne by the membrane separation process will be unstable, which will damage the membrane over a long period of time, and the separation effect of the membrane will deteriorate, shortening the actual service life of the membrane.

[0044] In the present invention, the membrane separation system 2 and the adsorption system 3 are respectively separated by independent vacuum pumps to perform organic waste gas separation and organic matter desorption. In this way, the two systems do not interfere with each other, and the intermittent vacuum operation of the adsorption system 3 will not affect the continuous vacuum operation of the membrane separation system 2, which effectively ensures the working stability of the membrane separation system 2 and protects the membrane. The membrane is more efficient, the separation effect of organic waste gas is better, and the service life of the membrane is effectively extended.

[0045] At the same time, compared with the prior art, in the present invention, the condensation system 1 is composed of a buffer tank 11 and a tail gas condenser 12. The original tail gas to be treated, the recovered tail gas enriched by the membrane, and the tail gas desorbed by the adsorbed filler all enter the buffer tank 11 for unified treatment. The buffer tank 11 can separate the entrained liquid and remove the mechanical impurities that may be entrained. At the same time, it stabilizes the system and prevents gases of different components from directly entering the post-installation device and influencing each other, so that the tail gas composition finally entering the membrane separation system 2 is relatively stable, which is conducive to the stable separation and treatment of organic waste gas by the membrane. The bottom of the buffer tank 11 regularly discharges the recovered solvent liquid, and the gas at the top of the buffer tank 11 enters the tail gas condenser 12 again, and the tail gas condenser 12 recovers part of the solvent to achieve solvent recovery. The buffer tank 11 and the tail gas condenser 12 are arranged in cooperation at the front end of the membrane separation system 2, which can pre-recover the solvent to a greater extent, reduce the tail gas load entering the membrane, and thus reduce the layout scale of the membrane device. This system is equivalent to setting up only one condenser to meet the recycling needs. There is no need to set up another condenser at the end of the adsorption system and membrane separation system, which simplifies the device scale of the overall organic waste gas recovery system, simplifies the operating steps, and saves production costs.

[0046] In this embodiment, the adsorption system 3 is composed of two (but not limited to) parallel adsorption tanks 31, and adsorption fillers are arranged in the adsorption tanks. The adsorption fillers are one or more of activated carbon / carbon fiber / macroporous resin / molecular sieve. The adsorption fillers complete adsorption and desorption operations in the adsorption tanks 31, and the adsorption and desorption processes of different adsorption tanks 31 are operated alternately.

[0047] The adsorption system 3 is connected with an adsorption air intake pipeline 32, a vacuum desorption pipeline 33, and an exhaust pipeline 34. The untreated waste gas of the membrane separation system 2 enters the adsorption tank 31 along the adsorption air intake pipeline 32, and the clean gas after adsorption treatment is discharged along the exhaust pipeline 34. In this embodiment, the waste gas enters from the bottom of the tank, and the clean gas goes out from the top of the tank, and the organic gas is adsorbed to the maximum extent; the vacuum desorption pipeline 33 is connected to the vacuum pump 25; the adsorption system 3 is also connected with a hot air intake pipeline 35, which is located at the top of the adsorption tank (31) and is used to introduce hot nitrogen or water vapor during the desorption operation. The hot air intake pipeline 35 is also provided with a self-acting pressure reducing valve, so that the hot nitrogen or water vapor can be stably transported.

[0048] The adsorption system 3 is also connected to a cooling air inlet pipeline 36 and a drying and cooling fan 6 for introducing dry air after desorption is completed to cool and dry the adsorption filler in the adsorption tank 31 .

[0049] The organic waste gas from the membrane separation system is sent to the adsorption tank. At this time, the concentration of organic matter in the waste gas has been greatly reduced. After the waste gas enters the adsorption tank in turn, the organic matter is adsorbed into the micropores of the adsorption filler under the action of van der Waals force. The filler is regenerated after adsorption saturation. After adsorption, the waste gas is converted into clean gas and discharged through the chimney in compliance with the standards.

[0050] In the prior art, the adsorbent regeneration process of the adsorption system relies on vacuum desorption. This desorption method has a relatively low desorption efficiency, a long complete desorption time, and incomplete desorption will cause part of the adsorbent to fail, reducing the adsorption efficiency of the adsorption system and limiting its overall treatment effect. For example, the adsorption filler adsorbs 3 kg of organic gas, and only 2 kg of gas can be desorbed by vacuum desorption per unit time (the time required for complete desorption in the present invention). Another 1 kg of adsorption filler is in a failed state due to saturation, which will affect the subsequent adsorption of gas, so the overall adsorption efficiency is limited.

[0051] In the present invention, in the desorption process of the adsorption filler, the organic matter adsorbed on the filler is desorbed by auxiliary input of hot nitrogen or steam, and at the same time, the mixed steam containing water vapor and organic vapor is blown out by steam purge, and the mixed steam containing water vapor and organic vapor is blown out and recovered back to the membrane system through the vacuum pump. Compared with vacuum desorption relying only on the vacuum pump, the desorption effect of the adsorption filler is better, the desorption time of the adsorption filler can be effectively reduced, the use efficiency of the adsorption filler is improved, and the adsorption efficiency of the adsorption filler is enhanced, and the working efficiency of the entire organic waste gas recovery system is further improved. The number of adsorption tanks of the adsorption system can be set according to the actual process to achieve the effects of one absorption and one desorption, two absorptions and one desorption, three absorptions and one desorption, etc., which are controlled by the automatic control system and automatically switch to alternately perform the adsorption and regeneration processes, thereby ensuring the continuous operation and continuous processing capacity of the adsorption system.

[0052] At the same time, a drying and cooling fan 6 is also added at the end of the adsorption system 3. When the desorption operation is completed, the adsorption filler has a high temperature and high humidity, which is not conducive to the adsorption operation to be performed later. The drying and cooling fan is set to introduce dry air to purge the adsorption filler to achieve the purpose of cooling and drying the adsorption filler. During the drying process, the water vapor after desorption and the organic matter remaining on the filler will be taken out, resulting in excessive emissions of dry tail gas for a short time. In order to ensure that the exhaust gas is always up to standard, the dry air exhaust is circulated internally to avoid the discharge of substandard gas in the initial stage of the dry air, so as to ensure that the entire exhaust gas treatment process meets the standard.

[0053] like Figure 2 As shown, this embodiment also provides an efficient organic waste gas recovery process, and the recovery process includes the following steps:

[0054] A. Buffering gas intake: the original tail gas to be treated, the recovered tail gas enriched after membrane separation, and the desorbed tail gas desorbed after adsorption enter the buffer tank 11 through the first intake pipeline 111, the second intake pipeline 112, and the third intake pipeline 113 respectively, and enter the tail gas condenser 12 after merging in the buffer tank 11; part of the tail gas to be treated is naturally condensed in the buffer tank 11, and the recovered solvent liquid is regularly discharged from the first solvent recovery outlet 114;

[0055] B. Condensation recovery: The above-mentioned tail gas to be treated is condensed at low temperature in the tail gas condenser 12, the recovered organic solvent is discharged from the second solvent recovery outlet 123, and the uncondensed tail gas enters the membrane separation system 2 from the membrane inlet pipeline 21; wherein the condensation temperature is adjusted according to the main components of the organic waste gas, but the condensation temperature used in the daily workshop can be used, and no additional temperature requirements are required.

[0056] C. Membrane separation: The uncondensed tail gas is separated by permeation in the membrane device 22 of the membrane separation system 2, and the vacuum pump 4 is continuously operated. Most of the organic gas enters the permeate side 221 of the membrane device 22 under the action of vacuum and membrane permeation, and the remaining gas enters the retentate side 222 of the membrane device 22; the recovered tail gas enriched in the permeate side 221 is circulated back to the buffer tank 11 through the vacuum pump 4 to merge with other gases and enter the B process; the organic waste gas on the retentate side 222 enters the adsorption system 3 through the adsorption air intake line 32;

[0057] D. Adsorption and emission: After the above-mentioned organic waste gas enters the adsorption tank 31 of the adsorption system 3, the organic matter is adsorbed into the micropores of the adsorption filler. After adsorption, the organic waste gas is converted into clean gas, and the clean gas after adsorption treatment is discharged along the exhaust pipeline 34 in compliance with the standards; after the adsorption filler is saturated with adsorption, the gas transmission adsorption is stopped, and the adsorption tank 31 enters the next process; at the same time, the organic waste gas inlet of the adsorption tank 31 is closed, and the organic waste gas enters other adsorption tanks 31 to continue the adsorption operation; the number of adsorption tanks can be set according to the actual process to achieve the effects of one absorption and one desorption, two absorptions and one desorption, three absorptions and one desorption, etc., which are controlled by the automatic control system, and automatically switch to alternately perform the adsorption and regeneration processes, so that the adsorption system can operate continuously and treat the organic waste gas;

[0058] E. Desorption: The adsorbent filler after adsorption saturation is subjected to high-temperature and vacuum desorption regeneration. Specifically, the vacuum pump 25 is turned on, and hot nitrogen or water vapor with stable pressure is input to the adsorption tank 31 through the hot gas inlet pipeline 35 to desorb the organic matter adsorbed on the filler. At the same time, the mixed steam containing water vapor and organic vapor is blown out by the purge of hot steam, and circulated back to the buffer tank 11 through the vacuum pump 25 to merge with other gases and enter the B process; after the desorption of the adsorbent filler is completed, the vacuum valve of the adsorption tank 31 is closed, and the adsorption tank 31 enters the next process;

[0059] F. Cooling: The above-mentioned adsorption tank 31 is cooled. Specifically, dry air is sent into the adsorption filler through the drying and cooling fan 6 to purge the adsorption filler, thereby achieving the purpose of cooling and drying the adsorption filler. After the purge, the gas is discharged through the exhaust pipeline 34. The adsorption tank 31 after cooling and dehumidification resumes its adsorption function and is recycled.

[0060] Specifically, in step F, at the initial stage of cooling, the air inlet of the drying and cooling fan 6 is connected to the outlet of the exhaust pipeline 34. The drying air exhaust at this stage is in an internal circulation state, and the adsorption filler can adsorb the residual organic gas blown up again until the exhaust gas detected at the exhaust pipeline 34 meets the standard, and then the connection between the drying and cooling fan 6 and the exhaust pipeline 34 is disconnected, and air is naturally inhaled and exhausted until the adsorption tank 31 drops to the normal working temperature. The drying and cooling fan 6 also has an air supply port for supplying air during the internal circulation.

[0061] In general, the organic waste gas recovery device and process provided by the present invention have a more reasonable arrangement of each subsystem, which not only improves the removal rate of organic gas in the organic waste gas tail gas, but also increases the treatment volume of tail gas per unit time, and the treatment efficiency is higher. At the same time, it also plays a certain protective role on the membrane and adsorption filler, prolongs their service life, has a higher application efficiency, and further reduces production costs. The organic waste gas recovery device and process can be applied to waste gas discharged in industries such as petrochemicals, fine chemicals, spraying, adhesive production, and pharmaceutical and pesticide manufacturing, and has a very wide range of applications.

[0062] It should be understood that although this specification is described according to implementation modes, not every implementation mode contains only one independent technical solution. This description of the specification is only for the sake of clarity. Those skilled in the art should regard the specification as a whole. The technical solutions in each implementation mode may also be appropriately combined to form other implementation modes that can be understood by those skilled in the art.

[0063] The series of detailed descriptions listed above are only specific descriptions of feasible implementation methods of the present invention. They are not intended to limit the scope of protection of the present invention. Any equivalent implementation methods or changes that do not deviate from the technical spirit of the present invention should be included in the scope of protection of the present invention.

Claims

1. An efficient organic waste gas recovery device, comprising a condensation system (1), a membrane separation system (2), an adsorption system (3), and a vacuum system, characterized in that: The condensation system (1) is used to condense the organic tail gas to form a liquid organic solvent; the membrane separation system (2) is connected to the condensation system and the adsorption system through pipelines; the adsorption system (3) is used to adsorb the organic tail gas; the tail gas to be treated passes through the condensation system (1), the membrane separation system (2), and the adsorption system (3) in sequence until it meets the standards and is discharged; The vacuum system comprises a vacuum pump 1 (4) and a vacuum pump 2 (5) which are operated independently, wherein the inlet and outlet of the vacuum pump 1 (4) are respectively connected to the membrane separation system (2) and the condensation system (1), and the organic gas separated from the membrane separation system (2) is circulated back to the condensation system (1) by the vacuum pump 1 (4); the inlet and outlet of the vacuum pump 2 (5) are respectively connected to the adsorption system (3) and the condensation system (1); the organic gas desorbed from the adsorption system (3) is circulated back to the condensation system (1) by the vacuum pump 2 (5); The adsorption system (3) is composed of two or more adsorption tanks (31) connected in parallel. Adsorption fillers are arranged in the adsorption tanks. The adsorption system (3) is connected to an adsorption air intake pipeline (32), a vacuum desorption pipeline (33), and an exhaust pipeline (34). The untreated waste gas of the membrane separation system (2) enters the adsorption tank (31) along the adsorption air intake pipeline (32), and the clean gas after adsorption treatment is discharged along the exhaust pipeline (34). The vacuum desorption pipeline (33) is connected to a second vacuum pump (5). The adsorption system (3) is also connected to a hot air intake pipeline (35) for introducing hot nitrogen or water vapor during the desorption operation. The adsorption system (3) is also connected to a cooling air inlet pipeline (36) and a drying and cooling fan (6) for introducing dry air after desorption is completed to cool and dry the adsorption filler in the adsorption tank (31); The condensation system (1) comprises a buffer tank (11) and a tail gas condenser (12); the inlet end of the buffer tank (11) is connected to a first air inlet pipeline (111), a second air inlet pipeline (112) and a third air inlet pipeline (113); the first air inlet pipeline (111) is used to transport the original tail gas to be treated, the second air inlet pipeline (112) is used to transport the recovered tail gas enriched in the membrane separation system (2), and the third air inlet pipeline (113) is used to transport the desorbed tail gas of the adsorption filler in the adsorption system (3); a first solvent recovery outlet (114) is provided at the bottom of the buffer tank (11); and a buffer tank gas outlet is also provided at the top of the buffer tank (11), which is connected to the tail gas condenser (12) via a tail gas condensation pipeline (115); The tail gas condenser (12) is provided with a cooling medium inlet (121) and a cooling medium outlet (122). The tail gas to be treated is condensed in the tail gas condenser (12) and part of the solvent is recovered. A second solvent recovery outlet (123) is provided at the bottom of the tail gas condenser (12). A condenser gas outlet (124) is also provided at the top of the tail gas condenser (12) and is connected to the membrane separation system (2) via a membrane inlet pipeline (21). The membrane separation system (2) is composed of a plurality of membrane devices (22) connected in series and / or in parallel; the membrane device (22) comprises a permeate side (221) and a retentate side (222), wherein the permeate side (221) is connected to a vacuum pump (4) via a membrane recovery pipeline (23); and the retentate side (222) is connected to an adsorption system (3) via an adsorption air inlet pipeline (32).

2. The efficient organic waste gas recovery device according to claim 1, characterized in that: A self-operated pressure reducing valve is also provided on the hot gas inlet pipeline (35).

3. The efficient organic waste gas recovery device according to claim 2, characterized in that: The adsorption filler is one or more of the filler types including activated carbon, carbon fiber, macroporous resin, and molecular sieve.

4. An efficient organic waste gas recovery process implemented by using the efficient organic waste gas recovery device as described in any one of claims 1 to 3, characterized in that: The recovery process comprises: A. Buffer gas intake: the original tail gas to be treated, the recovered tail gas enriched after membrane separation, and the desorbed tail gas desorbed after adsorption enter the buffer tank (11) through the first gas intake pipeline (111), the second gas intake pipeline (112), and the third gas intake pipeline (113), respectively, and enter the tail gas condenser (12) after merging in the buffer tank (11); part of the tail gas to be treated is naturally condensed in the buffer tank (11), and the recovered solvent liquid is regularly discharged from the first solvent recovery outlet (114); B. Condensation recovery: the tail gas to be treated is condensed at low temperature in the tail gas condenser (12), the recovered organic solvent is discharged from the second solvent recovery outlet (123), and the uncondensed tail gas enters the membrane separation system (2) from the membrane inlet pipeline (21); C. Membrane separation: the uncondensed tail gas is separated by permeation in the membrane device (22) of the membrane separation system (2). The vacuum pump (4) operates continuously. Most of the organic gas enters the permeate side (221) of the membrane device (22) under the action of vacuum and membrane permeation, and the remaining gas enters the retentate side (222) of the membrane device (22); the recovered tail gas enriched in the permeate side (221) is circulated back to the buffer tank (11) through the vacuum pump (4) to merge with other gases and enter the B process; the organic waste gas on the retentate side (222) enters the adsorption system (3) through the adsorption air inlet pipeline (32); D. Adsorption and emission: After the organic waste gas enters the adsorption tank (31) of the adsorption system (3), the organic matter is adsorbed into the micropores of the adsorption filler. After adsorption, the organic waste gas is converted into clean gas, and the clean gas after adsorption treatment is discharged along the exhaust pipeline (34) in compliance with the standards. After the adsorption filler is saturated with adsorption, the gas supply adsorption is stopped, and the adsorption tank (31) enters the next process. At the same time, the organic waste gas inlet of the adsorption tank (31) is closed, and the organic waste gas enters other adsorption tanks (31) to continue the adsorption operation. Each adsorption tank (31) is controlled by an automatic control system, and automatically switches to alternately perform the adsorption and regeneration processes, so that the adsorption system can operate continuously and treat the organic waste gas. E. Desorption: The adsorbent filler after adsorption saturation is subjected to high-temperature vacuum desorption regeneration. Specifically, the vacuum pump 2 (5) is turned on, and hot nitrogen or water vapor with stable pressure is input into the adsorption tank (31) through the hot gas inlet pipeline (35) to desorb the organic matter adsorbed on the filler. At the same time, the mixed vapor containing water vapor and organic vapor is blown out by the hot steam purge, and circulated back to the buffer tank (11) through the vacuum pump 2 (5) to merge with other gases and enter the B step. After the desorption of the adsorbent filler is completed, the vacuum valve of the adsorption tank (31) is closed, and the adsorption tank (31) enters the next step. F. Cooling: The above-mentioned adsorption tank (31) is cooled. Specifically, dry air is introduced through the drying and cooling fan (6) to purge the adsorption filler, thereby achieving the purpose of cooling and drying the adsorption filler. After the purge, the gas is discharged through the exhaust pipeline (34). After the cooling and dehumidification, the adsorption tank (31) resumes its adsorption function and is recycled.

5. The efficient organic waste gas recovery process according to claim 4, characterized in that: In step F, at the initial stage of cooling, the air inlet of the drying and cooling fan (6) is connected to the outlet of the exhaust pipeline (34). The drying air exhaust at this stage is in an internal circulation state until the exhaust gas detected at the exhaust pipeline (34) meets the standard. The connection between the drying and cooling fan (6) and the exhaust pipeline (34) is disconnected, and air is naturally inhaled and exhausted until the adsorption tank (31) drops to the normal operating temperature.

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