Storage tank breathing tail gas recovery treatment system

Abstract

The utility model discloses a storage tank breathing tail gas recovery processing system which comprises a breathing valve expiration pipe, a solution recovery tank, a condensation recoverer and a gas permeable membrane separation device, the storage tank breathing tail gas recovery processing system is provided with a tail gas inlet, a liquid outlet and a gas outlet, the tail gas inlet is communicated with the breathing valve expiration pipe, and the liquid outlet is communicated with the solution recovery tank; the device is provided with a mixed gas inlet, a concentrated gas outlet and a discharged tail gas outlet, the mixed gas inlet is communicated with a gas outlet of the condensation recoverer, and the concentrated gas outlet is communicated with the gas outlet of the condensation recoverer through a vacuum pump. According to the utility model, part of solvent is recovered after condensation by the condenser, the tail gas load caused by concentrated gas entering the membrane separation device is reduced, the scale of the membrane separation device is reduced, and the rest gas enters the membrane separation device; the enriched recovery tail gas is circulated back to a tail gas inlet of the condenser through a vacuum pump and is subjected to condensation recovery together with the breathing tail gas of the storage tank, and the rest is subjected to gas membrane separation recovery; and the tail gas subjected to membrane treatment enters a VOCs tail gas treatment system.

Description

Technical Field

[0001] The utility model relates to a volatile organic gas recovery system, in particular to a storage tank breathing tail gas recovery and treatment system. Background Technique

[0002] In the pharmaceutical and fine chemical industries, storage tanks are widely used to store liquid chemical raw materials or finished products. Generally, dome tanks are used, accompanied by nitrogen sealing. When the storage tank is filled with materials (large breathing) or the outdoor temperature rises and the liquid inside the storage tank heats up (small breathing), the pressure inside the tank increases. To prevent the tank body from being damaged, the gas is discharged through a breathing valve, thereby reducing the tank pressure and automatically closing when the pressure reaches equilibrium to ensure the safety of the storage tank. The large and small breathing exhausts of the breathing valve are intermittent (irregular) exhausts, accompanied by high-concentration VOCs and relatively small gas volumes.

[0003] Traditional VOCs tail gas recovery devices for storage tank breathing tail gas have problems such as large investment, high energy consumption, low recovery efficiency, high instantaneous concentration, large gas flow fluctuations, and the generation of waste liquid and hazardous waste. Currently, the main methods for recovering storage tank breathing tail gas include: First, cryogenic technology: Its process principle is simple, and the recovery rate can reach about 90%. However, the device has a large power, high energy consumption, requires liquid nitrogen compression, has high requirements for pressure equipment, and due to the low temperature, the moisture in the tail gas is easy to freeze and cause blockage, and it is easy to have a pressure build-up if not processed in time. Second, compression and membrane technology: It has good treatment effects, a simple process, and the recovery rate can reach more than 90%. However, the device has a large power, high energy consumption, and due to the introduction of compression, it has high requirements for pressure equipment and has a certain danger to gases within the flammable and explosive range. Third, single membrane technology: It has good treatment effects, a simple process, low operating costs, no safety hazards, a high recovery rate, and an effective recovery rate exceeding 95%. However, it has high requirements for the water content and solid content of the treated tail gas. Content of the Utility Model

[0004] The purpose of the utility model is to provide a storage tank breathing tail gas recovery and treatment system with a reasonable structure, which can efficiently and with low energy consumption recover the organic components of the tail gas discharged from the breathing valve, reuse them in a resourceful way, and reduce emissions.

[0005] The purpose of the utility model is achieved as follows:

[0006] A storage tank breathing tail gas recovery and treatment system includes a breathing valve exhaust pipe and a solution recovery tank, and also includes a condensation recovery device, which is provided with a tail gas inlet, a liquid outlet, and a gas outlet. The tail gas inlet is communicated with the breathing valve exhaust pipe, and the liquid outlet is communicated with the solution recovery tank; a gas permeable membrane separation device, which is provided with a mixed gas inlet, a concentrated gas outlet, and an exhaust tail gas outlet. The mixed gas inlet is communicated with the gas outlet of the condensation recovery device, and the concentrated gas outlet is communicated with the gas outlet of the condensation recovery device through a vacuum pump.

[0007] The object of the present utility model can also be solved by the following technical measures:

[0008] As a more specific solution, the exhaust gas outlet is connected to the post-membrane tail gas treatment system.

[0009] The VOCs gas source of the storage tank breathing tail gas is mainly organic solvents, such as alkanes (n-hexane, n-heptane, gasoline, diesel, etc.), alcohols (methanol, ethanol, propanol, butanol, isoamyl alcohol, etc.), ketones (acetone, butanone, isopentanone, etc.), ethers (diethyl ether, butyl ether, isopropyl ether, methyl isobutyl ether, etc.), halogenated hydrocarbons (methylene chloride, chloroform, carbon tetrachloride, etc.), benzene rings (benzene, toluene, xylene, etc.), esters (ethyl acetate, butyl acetate, etc.), organic amines (triethylamine, diisopropylamine, etc.), which are organic substances that are liquid at room temperature, volatile, have a relatively high saturated vapor pressure, and a relatively low recovery rate.

[0010] As a further solution, the post-membrane tail gas treatment system is any one of a semiconductor catalytic device, a spray tower water washing device, and an adsorption device.

[0011] As a further solution, the storage tank is a domed tank, and a breathing valve is provided at the top of the domed tank. The breathing valve is provided with an air inlet and an air outlet, and the air outlet is connected to the breathing valve exhale pipe.

[0012] The beneficial effects of the present utility model are as follows:

[0013] (1) This storage tank breathing tail gas recovery and treatment system recovers part of the solvent after condensation by a condenser, realizes solvent recovery, reduces the tail gas load entering the membrane separation system, reduces the scale of the membrane separation system device, and the remaining gas enters the membrane separation system device (gas permeation membrane separation device). The enriched recovered tail gas is circulated back to the tail gas inlet of the condenser through a vacuum pump to converge with the storage tank breathing tail gas and is condensed again to recover part, and the rest is subjected to gas membrane separation and recovery; the tail gas after membrane treatment enters the subsequent VOCs tail gas treatment system.

[0014] (3) This storage tank breathing tail gas recovery and treatment system combines condensation recovery and gas membrane separation recovery, saves energy and reduces emissions. The membrane system separates and recovers VOCs gas from air, with low energy consumption, high efficiency, low concentration of post-membrane tail gas treatment, small and stable gas volume, which helps the subsequent tail gas treatment to meet the standards stably. This recovery process has no waste liquid or hazardous waste, does not require heating and desorption, does not contact with air, has no high-pressure deep cooling, and can be skid-mounted and integrated. BRIEF DESCRIPTION OF THE DRAWINGS

[0015] Figure 1 It is a schematic structural diagram of an embodiment of the present utility model.

[0016] Figure 2 It is a schematic structural diagram of the gas permeation membrane separation device of the present utility model from a certain angle.

[0017] Figure 3 This is a schematic diagram of the structure of the gas permeable membrane separation device in the present utility model from another angle.

[0018] Figure 4 This is a schematic diagram of the water washing structure of the spray tower in the present utility model. Specific embodiments

[0019] The present utility model will be further described below in conjunction with the accompanying drawings and embodiments:

[0020] See Figures 1 to 4 as shown

[0021] A storage tank breathing tail gas recovery and treatment system includes a breathing valve exhaust pipe 13 and a solution recovery tank 3, and further includes a condensation recovery device 2, which is provided with a tail gas inlet 21, a liquid outlet 23 and a gas outlet 22. The tail gas inlet 21 is communicated with the breathing valve exhaust pipe 13, and the liquid outlet 23 is communicated with the solution recovery tank 3;

[0022] A gas permeable membrane separation device 4, which is provided with a mixed gas inlet 41, a concentrated gas outlet 43 and an exhaust tail gas outlet 42. The mixed gas inlet 41 is communicated with the gas outlet 22 of the condensation recovery device 2, and the concentrated gas outlet 43 is communicated with the gas outlet 22 of the condensation recovery device 2 through a vacuum pump 5.

[0023] The gas permeable membrane separation device 4 includes a housing 44, a perforated central tube 46 and a permeation layer 45. The outer wall of the perforated central tube 46 is provided with a plurality of through holes. The permeation layer 45 includes multiple membrane bags and a permeation gas flow channel layer. The multiple membrane bags and the permeation gas flow channel layer are stacked at intervals and wound around the outer periphery of the perforated central tube. The membrane bag includes a concentrated gas flow channel layer and a membrane sheet, and the concentrated gas flow channel layer is wrapped outside the membrane sheet; The housing is wrapped outside the perforated central tube, the multiple membrane bags and the permeation gas flow channel layer. One end of the housing corresponding to the permeation layer 45 and one end of the perforated central tube are respectively provided with the exhaust tail gas outlet 42 and the concentrated gas outlet 43, and the other end of the housing corresponding to the permeation layer 45 is provided with the mixed gas inlet 41.

[0024] The gas permeation membrane separation device 4 (membrane separation system) is a prior art. The principle of recovering organic gases is to achieve physical separation of organic gas molecules and air molecules by utilizing the different selective permeability of polymer membrane materials. Under the driving force of the pressure difference on both sides of the membrane, the organic gas and air mixture follows the solution-diffusion mechanism, enabling the organic gas in the mixture to preferentially permeate through the membrane and be enriched and recovered, while the air is selectively intercepted. Thus, clean air with organic gases removed is obtained on the retentate side of the membrane, and enriched organic gases are obtained on the permeate side of the membrane, achieving the separation of organic gases and air. The mixed gas enters the membrane module from the mixed gas inlet 41 on the outer side of one end of the membrane module. After the permeation of the membrane sheet layer, the exhaust gas flows out of the exhaust gas outlet 42 on the outer side of the other end, and the permeated concentrated permeate gas is discharged from the concentrated gas outlet 43 of the central pipe of the membrane separation system.

[0025] The exhaust gas outlet 42 is connected to the post-membrane tail gas treatment system.

[0026] The post-membrane tail gas treatment system is any one of the spray tower water washing device 7, semiconductor catalytic device 8, and adsorption device 9.

[0027] Spray tower water washing device 7 (as shown in Figure 4 ): The post-membrane tail gas can be acid-washed and alkali-washed through the spray tower water washing device and then discharged up to the standard. The spray tower water washing device 7 includes a spray tower body 71, a water pump 75, a circulation water tank 74, and a spray pipe 76. An air inlet 72 and an exhaust port 73 are respectively provided at the lower and upper parts of the spray tower body 71. The spray pipe 76 is arranged inside the spray tower body 71 and between the air inlet 72 and the exhaust port 73. The circulation water tank 74 is arranged at the bottom of the spray tower body 71. The bottom of the spray tower body 71 is communicated with the circulation water tank 74. The circulation water tank 74 is connected to the spray pipe 76 through the water pump 75. The water pump 75 pumps the water in the circulation water tank 74 to the spray pipe 76 to spray inside the spray tower body 71. The exhaust gas flowing from bottom to top is washed until it reaches the emission standard and then discharged.

[0028] Semiconductor catalytic device: The post-membrane tail gas can pass through the semiconductor catalytic device. Through UVALED irradiation and foam ceramic-based honeycomb ceramic-based micron-sized anatase titanium dioxide, the low-concentration VOCs after the membrane are efficiently decomposed and then discharged up to the standard.

[0029] Adsorption device: The post-membrane tail gas can be adsorbed by the activated carbon or silicon-based mesoporous material adsorption device and then discharged up to the standard.

[0030] The storage tank is a domed tank 10. A breather valve 1 is provided at the top of the domed tank 10. The breather valve 1 is provided with an air inlet 12 and an air outlet 11. The air outlet 11 is connected to the breather valve exhaust pipe 13.

[0031] Its working principle is as follows: The storage tank discharges gas (breathing tail gas) through the exhalation port 11 of the breathing valve 1. The breathing tail gas condenses and recovers part of the solvent in the condensation recovery device 2, realizing solvent recovery, reducing the tail gas load of the gas permeation membrane separation device 4, and reducing the scale of the gas permeation membrane separation device 4. The gas condensed by the condensation recovery device 2 enters the gas permeation membrane separation device 4. The enriched recovered tail gas is circulated back to the tail gas inlet of the condensation recovery device 2 through the vacuum pump 5 to converge with the breathing tail gas of the storage tank; the tail gas after membrane treatment enters the subsequent VOCs tail gas treatment system.

[0032] The following combines data to illustrate its effects: Before treatment, the VOCs air volume is 5 - 500 m³ / h, and the concentration is 3000 - 300000 mg / m³. After the membrane separation system, the VOCs air volume is 0.1 - 2 m³ / h, and the concentration is 10 - 5000 mg / m³, and the recovery efficiency exceeds 95%.

[0033] The above is the preferred solution of the present invention, which shows and describes the basic principle, main features and advantages of the present invention. Those skilled in the art should understand that the present invention is not limited by the above embodiments. What is described in the above embodiments and the specification only illustrates the principle of the present invention. Without departing from the spirit and scope of the present invention, the present invention will have various changes and improvements, and these changes and improvements all fall within the scope of the present invention claimed. The scope of protection claimed by the present invention is defined by the appended claims and their equivalents.

Claims

1. A storage tank breathing tail gas recovery and treatment system, comprising a breather valve exhaust pipe (13) and a solution recovery tank (3), characterized in that: It further comprises a condensation recovery device (2), which is provided with a tail gas inlet (21), a liquid outlet (23) and a gas outlet (22). The tail gas inlet (21) is communicated with the breather valve exhaust pipe (13), and the liquid outlet (23) is communicated with the solution recovery tank (3); A gas permeable membrane separation device (4), which is provided with a mixed gas inlet (41), a concentrated gas outlet (43) and an exhaust tail gas outlet (42). The mixed gas inlet (41) is communicated with the gas outlet (22) of the condensation recovery device (2), and the concentrated gas outlet (43) is communicated with the gas outlet (22) of the condensation recovery device (2) through a vacuum pump (5).

2. The storage tank breathing tail gas recovery and treatment system according to claim 1, wherein: The exhaust tail gas outlet (42) is connected to a post-membrane tail gas treatment system.

3. The storage tank breathing tail gas recovery and treatment system according to claim 2, wherein: The post-membrane tail gas treatment system is any one or more of a semiconductor catalytic device (8), a spray tower water washing device (7), and an adsorption device (9).

4. The storage tank breathing tail gas recovery and treatment system according to claim 1, characterized in that: The storage tank is a dome tank (10). A breather valve (1) is provided at the top of the dome tank (10). The breather valve (1) is provided with an air inlet (12) and an air outlet (11), and the air outlet (11) is connected to the breather valve exhaust pipe (13).

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