Sewage treatment method, device and application

Abstract

The invention relates to the technical field of environmental protection, and discloses a sewage treatment method and device and application. The method comprises the following steps: S1, spraying absorbent fog drops to the liquid level of the sewage to obtain a rich-liquid oil phase and a water phase; s2, the rich liquid oil phase is subjected to desorption treatment, and rich gas and a circulating absorbent are obtained; s3, condensing the rich gas to obtain gaseous light hydrocarbon and liquid light hydrocarbon; the sewage contains greasy dirt, and the greasy dirt contains at least one of VOCs with the carbon atom number not larger than 12. According to the method provided by the invention, VOCs volatilized from the sewage can be absorbed, volatilization of the VOCs in the sewage can be inhibited, and the liquid light hydrocarbon and the gaseous light hydrocarbon are prepared.

Description

Technical Field

[0001] The present invention relates to the technical field of environmental protection, and particularly relates to a sewage treatment method, device and application. Background Art

[0002] During the industrial production process of oilfields or refining enterprises, oily sewage is often generated, and there are oil flowers in sewage ponds or process ponds, thus volatilizing VOCs waste gas. The existing VOCs waste gas treatment methods mainly lay a closed facility above the sewage pond and carry out treatment through organized collection. Due to factors such as frequent liquid level fluctuations and temperature changes, although the concentration of VOCs waste gas generated above the sewage pond is not high (hundreds of mg / m 3 ~tens of thousands of mg / m 3 ), the flow rate to be treated is often as high as tens of thousands of m 3 / h, resulting in extremely high energy consumption of the treatment device, insignificant economic benefits and high costs.

[0003] The existing methods for treating large-flow and low-concentration VOCs are mainly incineration method, catalytic oxidation method or low-temperature plasma decomposition method, etc. Due to the large volatility of the treatment concentration, the above methods often have flash explosions, great potential safety hazards, and at the same time, no economic value can be generated.

[0004] CN101062463A discloses a comprehensive purification method for malodorous waste gas. The low-concentration VOCs malodorous waste gas dissipated from structures such as the aeration tank of the sewage treatment plant is first treated by a washing-adsorption process, and the treated purified gas is discharged up to standard; the catalytic combustion tail gas is used to desorb and regenerate the adsorbent, and the desorbed and regenerated waste gas is mixed with the higher-concentration VOCs waste gas dissipated from structures such as the oil separation tank and flotation tank and treated by a desulfurization and total hydrocarbon concentration equalization-catalytic combustion technology. This process can comprehensively purify the VOCs-containing waste gas dissipated from each structure of the sewage treatment plant, and has a high purification efficiency for the pollutants (malodorous components and volatile organic components) in the waste gas. However, this method has a complex process, large investment, and relatively high operating temperature and poor safety.

[0005] Therefore, there is an urgent need to find a sewage treatment method for VOCs that is safe, low in energy consumption and high in economic benefits. Summary of the Invention

[0006] The purpose of the present invention is to capture the VOCs volatilized above the sewage, and at the same time, can in-situ inhibit the volatilization of VOCs in the sewage, and produce liquid light hydrocarbons and gaseous light hydrocarbons.

[0007] To achieve the above purpose, the first aspect of the present invention provides a sewage treatment method, which includes:

[0008] S1: Spraying absorbent droplets on the liquid surface of the sewage to obtain a rich liquid oil phase and an aqueous phase;

[0009] S2: Desorb the rich liquid oil phase to obtain rich gas and recycled absorbent;

[0010] S3: Condense the rich gas to obtain gaseous light hydrocarbons and liquid light hydrocarbons;

[0011] Wherein, in step S1, the particle diameter range of the absorbent droplets is not greater than 1000 μm, the absorbent droplets are obtained by atomizing the absorbent, and the saturated water content of the absorbent at 25 °C ≤ 2 mol%;

[0012] The sewage contains oil stains, and the oil stains contain at least one of VOCs with no more than 12 carbon atoms.

[0013] The second aspect of the present invention provides a sewage treatment device, including a pool body, a desorption unit and a condensation unit connected in sequence;

[0014] The sewage pool includes a pool body, and an atomizing spray unit is provided above the pool body. The particle diameter range of the atomized particles of the atomizing spray unit is not greater than 1000 μm, and the atomizing spray unit is used to spray absorbent droplets into the sewage in the pool body;

[0015] The desorption unit is also connected to the atomizing spray unit through a recovery pipeline. The desorption unit is used to desorb the rich liquid oil phase from the pool body and recycle the recycled absorbent obtained by the desorption treatment back to the atomizing spray unit;

[0016] The condensation unit is used to condense the rich gas from the desorption unit.

[0017] The third aspect of the present invention provides the application of the foregoing sewage treatment method and sewage treatment device in sewage treatment.

[0018] The technical solution provided by the present invention has the following advantages:

[0019] The sewage treatment method provided by the present invention can, on the one hand, absorb the VOCs volatilized from the sewage. Further, when the absorbent droplets fall into the sewage after absorbing VOCs, they can quickly separate oil and water, mix with the oil stains in the sewage, further absorb the VOCs in the oil stains, and also inhibit the volatilization of VOCs in the sewage; on the other hand, it can also desorb to obtain a recycled absorbent, enabling the absorbent to be reused, which is economical and environmentally friendly. Moreover, it can also recover and produce stable liquid light hydrocarbons and gaseous light hydrocarbons, having high economic benefits.

[0020] The sewage treatment device provided by the present invention can treat sewage containing VOCs, and can also produce stable liquid light hydrocarbons. Moreover, the device has a simple structure, a small volume, a low investment cost, and high practical value. Description of the Drawings

[0021] Figure 1 is a schematic structural diagram of the use of a system for treating sewage containing VOCs provided by some embodiments of the present invention;

[0022] Figure 2 is a schematic structural diagram of the use of a system for treating sewage containing VOCs provided by some other preferred embodiments of the present invention.

[0023] Explanation of reference numerals

[0024] 1. Pool body; 2. Desorption unit; 3. Condensation unit; 4. Atomizing spray unit; 6. Recovery pipeline; 8. Air extraction pump; 9. Liquid-liquid separator; 10. Sewage circulation pipeline;

[0025] 11. Sewage; 12. Rich liquid oil phase; 13. VOCs concentration monitor; 14. Filter; 15. Pool cover; 16. Clean air discharge port;

[0026] 21. Desorption container; 22. Stirring member; 23. Heater;

[0027] 41. Atomizing nozzle;

[0028] 51. Liquid hydrocarbon collection unit; 52. Gaseous hydrocarbon collection unit. Detailed implementation manners

[0029] The endpoints and any values within the ranges disclosed herein are not limited to the exact ranges or values, and these ranges or values should be understood to include values close to these ranges or values. For numerical ranges, the endpoint values of each range, between the endpoint values of each range and individual point values, and between individual point values can be combined with each other to obtain one or more new numerical ranges, and these numerical ranges should be regarded as specifically disclosed herein.

[0030] In order to make the technical problems, technical solutions and beneficial effects to be solved by the present invention more clearly understood, the present invention will be further described in detail below with reference to the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are only used to explain the present invention and are not used to limit the present invention.

[0031] It should be noted that when an element is referred to as "fixed to" or "disposed on" another element, it can be directly on the other element or indirectly on the other element. When an element is referred to as "connected to" another element, it can be directly connected to the other element or indirectly connected to the other element.

[0032] It should be understood that the orientation or positional relationship indicated by terms such as "length", "width", "upper", "lower", "front", "rear", "left", "right", "vertical", "horizontal", "top", "bottom", "inner", "outer", etc. is based on the orientation or positional relationship shown in the drawings, and is only for the convenience of describing the present invention and simplifying the description, rather than indicating or implying that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and therefore should not be construed as a limitation to the present invention.

[0033] The endpoints and any values within the ranges disclosed herein are not limited to the exact ranges or values. These ranges or values should be understood to include values close to these ranges or values. For numerical ranges, between the endpoint values of each range, between the endpoint values of each range and individual point values, and between individual point values, they can be combined with each other to obtain one or more new numerical ranges, and these numerical ranges should be regarded as specifically disclosed herein.

[0034] As described above, the present invention provides a sewage treatment method, which includes:

[0035] S1: Spraying absorbent droplets onto the liquid surface of the sewage to obtain a rich liquid oil phase and an aqueous phase;

[0036] S2: Subjecting the rich liquid oil phase to desorption treatment to obtain rich gas and a recycled absorbent;

[0037] S3: Condensing the rich gas to obtain gaseous light hydrocarbons and liquid light hydrocarbons;

[0038] Wherein, in step S1, the particle diameter range of the absorbent droplets is not greater than 1000 μm, the absorbent droplets are obtained by atomizing after passing through the absorbent, and the saturated water content of the absorbent at 25 °C ≤ 2 mol%;

[0039] The sewage contains oil stains, and the oil stains include at least one of VOCs with no more than 12 carbon atoms.

[0040] It should be noted that in the present invention, the saturated water content of the absorbent is measured according to the Karl Fischer titration method.

[0041] It should be noted that in the present invention, the recycled absorbent in step S2 can be atomized into absorbent droplets and recycled to step 1 for reuse, which is environmentally friendly and economical.

[0042] The sewage treatment method provided by the present invention can, on the one hand, absorb the VOCs volatilized from the sewage. Further, when the absorbent droplets fall into the sewage after absorbing VOCs, they can quickly separate oil and water, mix with the oil in the sewage, further absorb the VOCs in the oil, and also inhibit the volatilization of VOCs in the sewage. On the other hand, it can also desorb to obtain a recycled absorbent, enabling the absorbent to be reused, which is economical and environmentally friendly. Moreover, it can also recover and produce stable liquid light hydrocarbons and gaseous light hydrocarbons, having high economic benefits.

[0043] According to some preferred embodiments of the present invention, in step S1, the proportion of the number of the absorbent droplets with a particle diameter range between 10 μm and 500 μm in the total number of the absorbent droplets is not less than 80%. Under this preferred condition, the absorption efficiency of the VOCs volatilized from the sewage is higher.

[0044] According to some preferred embodiments of the present invention, in step S1, relative to the liquid level of every 100 m 2 of the sewage, the spraying flow rate of the absorbent droplets is 5 L / min - 20 L / min. Under this preferred condition, the absorption efficiency of the VOCs volatilized from the sewage is higher, and the effect of in-situ inhibiting the volatilization of VOCs from the sewage is better.

[0045] It should be noted that in the present invention, the spraying flow rate of the absorbent droplets is calculated based on the consumption flow rate of the liquid absorbent before atomization.

[0046] According to some preferred embodiments of the present invention, in step S1, the spraying is intermittent spraying.

[0047] Preferably, when the concentration of VOCs at a position 50 mm - 150 mm above the sewage is greater than or equal to the set value C1, the absorbent droplets are sprayed onto the liquid level of the sewage until the concentration fluctuation range of the VOCs at this position is not greater than 10 mg / m 3 , where C1 is 60 mg / m 3 -120 mg / m 3 , when the concentration of the VOCs at this position no longer changes, the concentration of the VOCs in the air at this position is C2.

[0048] That is to say, through the technical solution of the present invention, the concentration of VOCs at a position 50 mm - 150 mm above the sewage can be reduced to C2. Through the technical solution provided by the present invention, C2 can be controlled to be 0 - 50 mg / m 3

[0049] According to some preferred embodiments of the present invention, when the concentration of VOCs at a position 100 mm above the sewage is greater than or equal to 60 mg / m 3When, spray the absorbent droplets onto the liquid surface of the sewage until the concentration of VOCs at this position is 0.

[0050] According to a particularly preferred embodiment of the present invention, the density of the absorbent is less than the density of water, and the kinematic viscosity is 20 mPa·s - 300 mPa·s at 25°C. Under this preferred condition, the absorbent droplets falling into the sewage can achieve oil-water separation faster to form a rich liquid oil phase.

[0051] More preferably, the density of the absorbent is 890 - 920 kg / m 3 .

[0052] According to some preferred embodiments of the present invention, the absorbent contains a hydrogen bond acceptor and a hydrogen bond donor with a molar ratio of 1:0.5 - 10. The hydrogen bond acceptor is at least one of menthol, thymol, tetrabutylammonium bromide, and tetraoctylammonium bromide, and the hydrogen bond donor is at least one of n-octanoic acid, n-heptanoic acid, palmitoleic acid, isolenic acid, and oleic acid. Under this preferred condition, VOCs volatilized above the sewage can be captured more efficiently, and the volatilization of VOCs in the sewage can be further inhibited.

[0053] More preferably, the hydrogen bond acceptor and the hydrogen bond donor are selected from at least one of the following component formulations: menthol and palmitoleic acid with a molar ratio of 1:1 - 3, tetrabutylammonium bromide and oleic acid with a molar ratio of 1:3 - 5, and menthol, tetrabutylammonium bromide, and oleic acid with a molar ratio of 1:0.5 - 2:3 - 10.

[0054] According to some preferred embodiments of the present invention, the absorbent further contains a composite component, which is a mixture of component A and component B. Component A is selected from at least one of p-xylene, methylcyclohexane, dipentene, terpinene, toluene, and n-hexane, and component B is selected from at least one of citronellol, C 4-8 saturated monohydric fatty alcohols, ethyl benzoate, isophorone, acetic acid, lactic acid, and pyruvic acid. The inventors of the present invention found that after adding the composite component to the absorbent, the absorbent droplets have a better effect on capturing VOCs volatilized above the sewage, and the in-situ inhibition effect on VOCs in the sewage is also better.

[0055] More preferably, the molar ratio of the composite component to the hydrogen bond acceptor is 0.01 - 0.2:1. Under this preferred condition, the effect of the absorbent droplets on capturing VOCs volatilized above the sewage is further enhanced, and the in-situ inhibition effect on VOCs in the sewage is also stronger.

[0056] Further preferably, in the composite component, the molar ratio of component A to component B is 1:0.1 - 1. Under this preferred condition, the absorbent has a better effect on absorbing VOCs.

[0057] According to some preferred embodiments of the present invention, in step S2, the temperature of the desorption treatment is 30°C - 80°C, the pressure is 0 - 10 kPa in terms of absolute pressure, and the time is 5 min - 30 min. Under these preferred conditions, the desorption efficiency of the rich liquid oil phase is better, the desorption effect is better, and compared with the fresh absorbent, the impurity content of the obtained recycled absorbent does not exceed 0.05 wt%.

[0058] More preferably, in step S2, the desorption treatment is carried out under stirring conditions, and the stirring rate is 50 rpm - 500 rpm; under these preferred conditions, the desorption efficiency of the rich liquid oil phase is better, and the desorption effect is better.

[0059] More preferably, in step S2, the pressure of the desorption treatment is 0 - 5 kPa in terms of absolute pressure. Under these preferred conditions, the desorption efficiency of the rich liquid oil phase is better, the desorption effect is better, and compared with the fresh absorbent, the impurity content of the obtained recycled absorbent does not exceed 0.01 wt%.

[0060] According to some preferred embodiments of the present invention, in step S2, the temperature of the condensation treatment is -60°C - 10°C, and the pressure is 0 - 10 bar in terms of gauge pressure. Under these preferred conditions, based on the total mass of the rich gas obtained by desorption, the mass of the stable liquid light hydrocarbons obtained by condensation is more. More preferably, the pressure of the condensation treatment is 3 bar - 10 bar in terms of gauge pressure.

[0061] According to some preferred embodiments of the present invention, this method is carried out in a sewage treatment device, such as Figure 1 as shown, the sewage treatment device includes a sewage tank, a desorption unit 2 and a condensation unit 3 connected in sequence,

[0062] The sewage tank includes a tank body 1, and above the tank body 1, there is an atomizing spray unit 4. The diameter range of the atomized particles of the atomizing spray unit 4 is not greater than 1000 μm, and the atomizing spray unit 4 is used to spray the absorbent droplets into the sewage 11 in the tank body 1;

[0063] The desorption unit 2 is also connected to the atomizing spray unit 4 through a recovery pipeline 6. The desorption unit 2 is used to carry out desorption treatment on the rich liquid oil phase 12 from the tank body 1, and recycle the recycled absorbent obtained by the desorption treatment back to the atomizing spray unit 4;

[0064] The condensation unit 3 is used to condense the rich gas from the desorption unit 2;

[0065] This method includes:

[0066] S1: Introduce the sewage into the tank body 1, and spray absorbent droplets onto the sewage 11 through the atomizing spray unit 4 to obtain the rich liquid oil phase 12 and the water phase 11.

[0067] S2: Introduce the rich liquid oil phase 12 into the desorption unit 2 for desorption treatment to obtain the rich gas and the recycled absorbent.

[0068] S3: Introduce the rich gas into the condensation unit 3 for condensation treatment to obtain the gaseous light hydrocarbons and the liquid light hydrocarbons.

[0069] Further preferably, as Figure 2 shown, the sewage treatment device further includes a liquid-liquid separator 9 provided between the tank body 1 and the desorption unit 2, and the liquid-liquid separator 9 is also connected to the tank body 1 through a sewage circulation pipeline 10.

[0070] This method further includes:

[0071] Before step S2, introduce the rich liquid oil phase 12 into the liquid-liquid separator 9 for liquid-liquid separation treatment to obtain moisture and the rich liquid oil phase 12 with a water content not exceeding 1 wt%, and recycle the moisture back to the tank body 1.

[0072] Under this preferred condition, the desorption efficiency of the rich liquid oil phase 12 is better, the impurity content of the obtained recycled absorbent is lower, and the absorption effect of this recycled absorbent on VOCs is better.

[0073] As Figure 1 shown, the sewage treatment device provided in the second aspect of the present invention includes a sewage tank, a desorption unit 2 and a condensation unit 3 connected in sequence;

[0074] The sewage tank includes a tank body 1, an atomizing spray unit 4 is provided above the tank body 1, the atomizing particle diameter range of the atomizing spray unit 4 is not greater than 1000 μm, and the atomizing spray unit 4 is used to spray absorbent droplets onto the sewage 11 in the tank body 1;

[0075] The desorption unit 2 is also connected to the atomizing spray unit 4 through a recovery pipeline 6. The desorption unit 2 is used to desorb the rich liquid oil phase 12 from the sewage tank and recycle the recycled absorbent obtained by the desorption treatment back to the atomizing spray unit 4;

[0076] The condensation unit 3 is used to condense the rich gas from the desorption unit 2.

[0077] It should be noted that the atomizing particle diameter range of the atomizing spray unit 4 being not greater than 1000 μm represents the specification of the atomizing spray unit 4 corresponding to the liquid being atomized into droplets not greater than 1000 μm by the atomizing spray unit 4.

[0078] The sewage treatment device provided by the present invention sprays absorbent droplets onto the surface of the sewage in the pool body through the atomizing spray unit, which can absorb the escaped VOCs gas and also inhibit the volatilization of VOCs in the sewage, so that the content of VOCs in the gas above the sewage is not greater than 60 mg / kg. Moreover, the rich liquid oil phase 12 formed by absorbing the VOCs gas can enter the desorption unit for desorption, thereby regenerating a recyclable circulating absorbent. The utilization rate of the absorbent is high, the system investment cost is low, the economic benefit is large, and it is environmentally friendly and safe.

[0079] In some embodiments of the present invention, the desorption unit 2 is fixedly connected to the sewage pool. By controlling the water level of the sewage 11 in the pool body 1, the rich liquid oil phase 12 above the sewage 11 can be introduced into the desorption unit 2, while the sewage 11 is not introduced into the desorption unit 2.

[0080] In some embodiments of the present invention, the desorption unit 2 is movably connected to the sewage pool. An oil-water sensor is provided at the rich liquid oil phase discharge port, and the rich liquid oil phase discharge port can move up and down following the rich liquid oil phase 12. When the oil-water sensor senses the oil phase and does not sense the water phase, the rich liquid oil phase discharge port opens, and the rich liquid oil phase 12 is introduced into the desorption unit 2; when the oil-water sensor senses the water phase, the rich liquid oil phase discharge port moves upward until the water phase is not sensed, and the rich liquid oil phase discharge port opens, and the rich liquid oil phase 12 is introduced into the desorption unit 2.

[0081] In some preferred embodiments of the present invention, as Figure 2 shown, the device further includes a liquid-liquid separator 9 provided between the pool body 1 and the desorption unit 2. The liquid-liquid separator 9 is also connected to the sewage pool through a sewage circulation pipeline 10. Since there is 0-10 wt% of water in the rich liquid oil phase 12 drawn from the sewage pool, the liquid-liquid separator 9 is used to separate the water in the rich liquid oil phase 12 and return the water to the pool body 1 of the sewage pool through the sewage circulation pipeline 10, and to carry out the separated rich liquid oil phase 12. Under this preferred condition, the regenerated circulating absorbent has a better effect, and the treatment effect on the sewage containing VOCs is better.

[0082] In some preferred embodiments of the present invention, the atomizing spray unit 4 includes at least one atomizing nozzle 41, and the atomizing nozzle 41 is an automatic rotating atomizing nozzle. Under this preferred condition, the atomizing spray effect is better, the absorption effect on the VOCs gas escaped from the sewage 11 is better, and it can be further reduced.

[0083] It should be noted that in the present invention, the spraying direction of the atomizing nozzle 41 can be any direction. Preferably, the spraying direction of the atomizing nozzle 41 is the horizontal direction. In this preferred case, the absorbent droplets are sprayed horizontally and fall downward under the action of gravity, which can prolong the residence time of the absorbent droplets in the air, and further improve the absorption efficiency of the absorbent droplets for VOCs in the air above the rich liquid oil phase 12.

[0084] In some preferred embodiments of the present invention, the sewage tank is further provided with a VOCs concentration monitor 13, which is used to monitor the VOCs concentration at a position 50 mm - 150 mm above the liquid surface of the sewage 11 in the tank body 1, so as to control the atomizing spraying unit 4 to spray absorbent droplets into the sewage 11 in the tank body 1 after the VOCs in the air above the sewage 11 reach a set value, thereby further reducing the dosage of the absorbent and saving costs without affecting the treatment effect of the device on VOCs sewage.

[0085] In some preferred embodiments of the present invention, the tank body 1 is provided with a rich liquid oil phase discharge port, and the rich liquid oil phase discharge port is provided with a filter 14, which is used to filter impurities in the rich liquid oil phase 12.

[0086] In some preferred embodiments of the present invention, the sewage tank further includes a tank cover 15, the atomizing spraying unit 4 is arranged below the tank cover 15, and the tank cover 15 is further provided with a clean gas discharge port 16. In this preferred case, the sewage 11 and the VOCs dissipated from the sewage 11 are treated in the accommodation cavity surrounded by the tank cover 15 and the tank body 1, and the content of VOCs in the gas above the treated sewage 11 is lower than 60 mg / m 3 After that, the gas 11 above the sewage 11 is discharged and vented through the clean gas discharge port 16.

[0087] In some preferred embodiments of the present invention, the sewage tank further includes a tank cover 15, the atomizing spraying unit 4 is arranged below the tank cover 15, and the side wall of the tank body 1 is further provided with a clean gas discharge port 16, which is used to discharge the gas with the content of VOCs lower than 60 mg / m 3 in the gas above the sewage 11.

[0088] It should be noted that the present invention has no special requirements for the installation position of the clean gas discharge port 16, as long as it is higher than the liquid surface of the rich liquid oil phase 12.

[0089] In some preferred embodiments of the present invention, the sewage tank is connected to the desorption unit 2 through an oil pump 7, and the oil pump 7 is used to pump out the rich liquid oil phase 12 in the sewage tank and transport it to the desorption unit 2.

[0090] In some other preferred embodiments of the present invention, the desorption unit 2 is arranged below the sewage tank. Under this preferred condition, there is no need to set up an oil extraction pump 7, and the rich liquid oil phase 12 in the tank body 1 is introduced into the desorption unit 2 by gravity.

[0091] In some preferred embodiments of the present invention, the desorption unit 2 is connected to the condensation unit 3 through an air extraction pump 8, and the air extraction pump 8 is used to pump the gas obtained by desorbing the rich liquid oil phase 12 in the desorption unit 2 to the condensation unit 3 for condensation treatment.

[0092] It should be noted that in the present invention, pumps can be arranged in the pipelines between the units or devices for liquid transmission, gas transmission or gas-liquid transmission between the units or devices.

[0093] In some preferred embodiments of the present invention, the desorption unit 2 includes a desorption container 21 and a heater 23 for heating the liquid material in the desorption container 21.

[0094] In some preferred embodiments of the present invention, the desorption unit 2 further includes a stirring member 22 arranged in the desorption container 21, and the stirring member 22 is used to stir the rich liquid oil phase 12 in the desorption unit 2 to improve the desorption efficiency of the rich liquid oil phase 12.

[0095] In some preferred embodiments of the present invention, the device further includes a product collection unit, and the product collection unit includes a liquid hydrocarbon collection unit 51 and a gaseous hydrocarbon collection unit 52. The liquid hydrocarbon collection unit 51 and the gaseous hydrocarbon collection unit 52 are independently connected to the condensation unit 3. The liquid hydrocarbon collection unit 51 is used to collect and store the liquid hydrocarbons obtained by condensation treatment, and the gaseous hydrocarbon collection unit 52 is used to collect and store the gaseous hydrocarbons obtained by condensation treatment.

[0096] As Figure 1 shown, the present invention provides a preferred application process of the sewage treatment device:

[0097] S1: After atomizing the absorbent into absorbent droplets not larger than 1000 μm through the atomizing spray unit 4, the absorbent droplets are sprayed onto the liquid surface of the sewage 11 in the tank body 1. During the process of the absorbent droplets falling from the atomizing spray unit 4 to the liquid surface of the sewage 11, the VOCs in the gas above the sewage 11 are absorbed, so that the content of VOCs in the gas is reduced to 60 mg / m 3 , after the absorbent droplets fall onto the liquid surface of the sewage 11, they quickly merge with the oil flowers on the surface of the sewage 11 to form a rich liquid oil phase 12, and can inhibit the volatilization of VOCs in the sewage 11;

[0098] S2: Introduce the rich liquid oil phase 12 from the pool body 1 into the desorption unit 2. Under the agitation of the agitator 22 and the heating of the heater 23, the rich liquid oil phase 12 undergoes desorption treatment to obtain rich gas and recycled absorbent;

[0099] S3: Introduce the rich gas into the condensation unit 3 for condensation treatment to obtain gaseous hydrocarbons and liquid hydrocarbons. Transport the gaseous hydrocarbons to the gaseous hydrocarbon collection unit 52 for collection and storage, and transport the liquid hydrocarbons to the liquid hydrocarbon collection unit 51 for collection and storage.

[0100] As Figure 2 shown, the present invention provides another preferred application process for the sewage treatment device:

[0101] S1: After atomizing the absorbent into absorbent droplets not larger than 1000 μm through the atomizing spray unit 4, spray the absorbent droplets onto the liquid surface of the sewage 11 in the pool body 1. During the process of the absorbent droplets falling from the atomizing spray unit 4 to the liquid surface of the sewage 11, the VOCs in the gas above the sewage 11 are absorbed, reducing the VOCs content in the gas to 60 mg / m 3 . After the absorbent droplets fall onto the liquid surface of the sewage 11, they quickly merge with the oil flowers on the surface of the sewage 11 to form the rich liquid oil phase 12, and can inhibit the volatilization of VOCs in the sewage 11;

[0102] S2: Introduce the rich liquid oil phase 12 into the liquid-liquid separator 9 for oil-water separation to obtain the rich liquid oil phase 12 with a water content not higher than 1 wt% and an aqueous phase. Return the aqueous phase to the pool body 1 of the sewage tank through the sewage circulation pipeline 10;

[0103] S3: Introduce the rich liquid oil phase 12 with a water content not higher than 1 wt% from the liquid-liquid separator 9 into the desorption unit 2. Under the agitation of the agitator 22 and the heating of the heater 23, the rich liquid oil phase 12 undergoes desorption treatment to obtain rich gas and recycled absorbent;

[0104] S4: Introduce the rich gas into the condensation unit 3 for condensation treatment to obtain gaseous hydrocarbons and liquid hydrocarbons. Transport the gaseous hydrocarbons to the gaseous hydrocarbon collection unit 52 for collection and storage, and transport the liquid hydrocarbons to the liquid hydrocarbon collection unit 51 for collection and storage.

[0105] The present invention will be described in detail below through examples. In the following examples, for the instruments, reagents, materials, etc. involved, unless otherwise specified, they are all conventional instruments, reagents, materials, etc. existing in the prior art and can be obtained through regular commercial channels. For the experimental methods, detection methods, etc. involved in the following examples, unless otherwise specified, they are all conventional experimental methods, detection methods, etc. existing in the prior art.

[0106] It should be noted that in the present invention, normal temperature means 25 °C and normal pressure means 101 kPa.

[0107] In the following examples, the sewage consists of 90 vol% water and 10 vol% oil contaminants. Based on the total volume of the oil contaminants, the composition of the oil contaminants is as follows: 0.21 wt% ethane + 0.82 wt% propane + 1.71 wt% n-butane + 1.91 wt% isopentane + 1.49 wt% n-hexane + 5.56 wt% 1,4-pentadiene + 4.27 wt% 1,3-cyclopentadiene + 2.56 wt% cyclopentadiene + 17.92 wt% benzene + 7.14 wt% 1-methyl-1,3-cyclopentadiene + 12.69 wt% toluene + 10.25 wt% p-xylene + 6.99 wt% m-xylene + 7.05 wt% styrene + 5.11 wt% p-methylstyrene + 3.16 wt% m-methylstyrene + 6.7 wt% dicyclopentadiene + 4.46 wt% indene.

[0108] In the following examples, the volume of the sewage is 400 m 3 , and the liquid surface area is 100 m 2 . The spraying area of the absorbent droplets is the same as the liquid surface area of the sewage.

[0109] In the following examples, the absorbents involved are shown in Table 1 below:

[0110] Table 1

[0111]

[0112] Note: The kinematic viscosity represents the kinematic viscosity of the absorbent under normal temperature and pressure conditions;

[0113] The saturated water content represents the saturated water content of the absorbent under normal temperature and pressure conditions.

[0114] The following examples are all carried out in a sewage treatment device. As Figure 1 shown, the device includes a sewage tank, a desorption unit 2, and a condensation unit 3 connected in sequence;

[0115] The sewage tank includes a tank body 1. Above the tank body 1, there is an atomizing spray unit 4. The atomizing particle diameter range of the atomizing spray unit 4 is not greater than 1000 μm. The atomizing spray unit 4 is used to spray absorbent droplets onto the sewage 11 in the tank body 1;

[0116] The desorption unit 2 is also connected to the atomizing spray unit 4 through a recovery pipeline 6. The desorption unit 2 is used to desorb the rich liquid oil phase 12 from the sewage tank and recycle the recycled absorbent obtained from the desorption treatment back to the atomizing spray unit 4;

[0117] The condensation unit 3 is used to condense the rich gas sourced from the desorption unit 2.

[0118] The sewage tank is also provided with a VOCs concentration monitor 13, which is used to monitor the VOCs concentration at a position 100 mm above the liquid level of the sewage 11 in the tank body 1.

[0119] The device further includes a product collection unit, which includes a liquid hydrocarbon collection unit 51 and a gaseous hydrocarbon collection unit 52. The liquid hydrocarbon collection unit 51 and the gaseous hydrocarbon collection unit 52 are each independently connected to the condensation unit 3. The liquid hydrocarbon collection unit 51 is used to collect and store the liquid hydrocarbons obtained by condensation treatment, and the gaseous hydrocarbon collection unit 52 is used to collect and store the gaseous hydrocarbons obtained by condensation treatment.

[0120] It should be noted that the following embodiments are the preferred embodiments of the present invention. The following embodiments are all carried out in this device, but it does not mean that they can only be carried out in this device.

[0121] Embodiment 1

[0122] S1: Spray absorbent droplets onto the liquid surface of the sewage to obtain a rich liquid oil phase and an aqueous phase;

[0123] S2: Carry out desorption treatment on the rich liquid oil phase to obtain rich gas and a recycled absorbent;

[0124] S3: Carry out condensation treatment on the rich gas to obtain gaseous light hydrocarbons and liquid light hydrocarbons;

[0125] Among them, the absorbent droplets are obtained by atomizing the absorbent.

[0126] Specifically, the parameters are shown in Table 2 below.

[0127] The gaseous light hydrocarbons produced are composed of: ethane + propane + n-butane;

[0128] The liquid light hydrocarbons are composed of: propane + n-butane + isopentane + n-hexane + 1,4-pentadiene + 1,3-cyclopentadiene + cyclopentadiene + benzene + 1-methyl-1,3-cyclopentadiene + toluene + p-xylene + m-xylene + styrene + p-methylstyrene + m-methylstyrene + dicyclopentadiene + indene.

[0129] Embodiments 2-6

[0130] Carry out according to the method of Embodiment 1, with some process parameters different. Specifically, they are shown in Table 2 below.

[0131] Embodiment 7

[0132] Carry out according to the method of Embodiment 1, with some process parameters different. Specifically, they are shown in Table 2 below.

[0133] The gaseous light hydrocarbons obtained are composed of the following components: propane + n-butane + isopentane + n-hexane + 1,4-pentadiene + 1,3-cyclopentadiene;

[0134] The liquid light hydrocarbons are composed of the following components: isopentane + n-hexane + 1,4-pentadiene + 1,3-cyclopentadiene + cyclopentadiene + benzene + 1-methyl-1,3-cyclopentadiene + toluene + p-xylene + m-xylene + styrene + p-methylstyrene + m-methylstyrene + dicyclopentadiene + indene.

[0135] Example 8:

[0136] It is carried out according to the method of Example 1, wherein the spraying flow rate of the absorbent droplets is different from that of Example 1, and other process parameters are the same as those of Example 1. Specifically, as shown in Table 2 below.

[0137] Example 9

[0138] It is carried out according to the method of Example 1, wherein the absorbent also contains a composite component, and other process parameters are the same as those of Example 1. Specifically, as shown in Table 2 below.

[0139] Comparative Example 1

[0140] It is carried out according to the method of Example 1, wherein the type of the absorbent is different, and other process parameters are the same as those of Example 1. Specifically, as shown in Table 2 below.

[0141] Comparative Example 2

[0142] It is carried out according to the method of Example 1, wherein the particle diameter range of the absorbent droplets is different, and other process parameters are the same as those of Example 1. Specifically, as shown in Table 2 below.

[0143] Table 2

[0144]

[0145]

[0146] Note:

[0147] d represents the particle diameter range of the absorbent droplets. d-1 represents that the particle diameter range of the absorbent droplets is 10 μm - 500 μm, d-2 represents that the particle diameter range of the absorbent droplets is 501 μm - 1000 μm, and d-3 represents that the particle diameter range of the absorbent droplets is 1500 μm - 2000 μm;

[0148] C0 is the VOCs concentration in the air 100 mm above the untreated sewage;

[0149] C1 is a set value. When the concentration of VOCs in the air 100 mm above the sewage is greater than or equal to this set value, absorbent droplets are sprayed onto the liquid surface of the sewage;

[0150] C2 is the average concentration of VOCs in the air at this position when the absorbent droplets are sprayed onto the liquid surface of the sewage until the concentration fluctuation of VOCs at this position does not exceed 10 mg / m 3 ;

[0151] The purity of the recycled absorbent = 100 wt% - the wt% of impurities, and the impurities are water and VOCs;

[0152] The proportion of liquid light hydrocarbons represents the mass proportion of the liquid light hydrocarbons condensed based on the total mass of the rich gas obtained by desorption.

[0153] Table 2 (continued)

[0154]

[0155]

[0156] Note:

[0157] d represents the particle diameter range of the absorbent droplets. d - 1 represents that the particle diameter range of the absorbent droplets is 10 μm - 500 μm, d - 2 represents that the particle diameter range of the absorbent droplets is 501 μm - 1000 μm, and d - 3 represents that the particle diameter range of the absorbent droplets is 1500 μm - 2000 μm;

[0158] C0 is the concentration of VOCs in the air 100 mm above the untreated sewage;

[0159] C1 is a set value. When the concentration of VOCs in the air 100 mm above the sewage is greater than or equal to this set value, absorbent droplets are sprayed onto the liquid surface of the sewage;

[0160] C2 is the average concentration of VOCs in the air at this position when the absorbent droplets are sprayed onto the liquid surface of the sewage until the concentration fluctuation of VOCs at this position does not exceed 10 mg / m 3 ;

[0161] The purity of the recycled absorbent = 100 wt% - the wt% of impurities, and the impurities are water and VOCs;

[0162] The proportion of liquid light hydrocarbons represents the mass proportion of the liquid light hydrocarbons condensed based on the total mass of the rich gas obtained by desorption.

[0163] The preferred embodiments of the present invention have been described in detail above. However, the present invention is not limited thereto. Within the scope of the technical concept of the present invention, various simple modifications can be made to the technical solutions of the present invention, including any other suitable combination of each technical feature. These simple modifications and combinations should also be regarded as the content disclosed by the present invention and fall within the protection scope of the present invention.

Claims

1. A sewage treatment method, characterized in that, The method includes: S1: Spraying absorbent droplets onto the liquid surface of the sewage to obtain a rich liquid oil phase and an aqueous phase; S2: Subjecting the rich liquid oil phase to desorption treatment to obtain rich gas and recycled absorbent; S3: Condensing the rich gas to obtain gaseous light hydrocarbons and liquid light hydrocarbons; Wherein, in step S1, the particle diameter range of the absorbent droplets is not greater than 1000 μm, the absorbent droplets are obtained by atomizing the absorbent, and the saturated water content of the absorbent at 25 °C ≤ 2 mol%; The sewage contains oil stains, and the oil stains include at least one of VOCs with no more than 12 carbon atoms.

2. The method according to claim 1, wherein In step S1, the proportion of the number of the absorbent droplets with a particle diameter range between 10 μm and 500 μm in the total number of the absorbent droplets is not less than 80%; Preferably, in step S1, relative to every 100 m 2 of the liquid level of the sewage, the spraying flow rate of the absorbent droplets is 5 L / min - 20 L / min.

3. The method according to claim 1, wherein In step S1, the spraying is intermittent spraying; Preferably, when the concentration of the VOCs at a position 50 mm - 150 mm above the sewage is greater than or equal to the set value C1, the absorbent droplets are sprayed onto the liquid surface of the sewage until the concentration fluctuation range of the VOCs at this position is not greater than 10 mg / m 3 , where C1 is 60 mg / m 3 -120 mg / m 3 .

4. The method according to claim 1, wherein The density of the absorbent is less than the density of water, and the kinematic viscosity at 25 °C is 20 mPa·s - 300 mPa·s; Preferably, the density of the absorbent is 890 - 920 kg / m 3 .

5. The method according to any one of claims 1-4, characterized in that The absorbent contains a hydrogen bond acceptor and a hydrogen bond donor with a molar ratio of 1:0.5 - 10. The hydrogen bond acceptor is at least one of menthol, thymol, tetrabutylammonium bromide, and tetraoctylammonium bromide, and the hydrogen bond donor is at least one of n-caprylic acid, n-heptanoic acid, palmitoleic acid, isolenic acid, and oleic acid.

6. The method according to claim 5, characterized in that The hydrogen bond acceptor and the hydrogen bond donor are selected from at least one of the following group formulations: Menthol and palmitoleic acid with a molar ratio of 1:1 - 3, tetrabutylammonium bromide and oleic acid with a molar ratio of 1:3 - 5, menthol, tetrabutylammonium bromide, and oleic acid with a molar ratio of 1:0.5 - 2:3 - 10.

7. The method according to claim 5, wherein The absorbent further contains a composite component, which is a mixture of component A and component B. Component A is selected from at least one of p-xylene, methylcyclohexane, dipentene, terpinene, toluene, and n-hexane, and component B is selected from at least one of citronellol, saturated monohydric aliphatic alcohols of C 4-8 and ethyl benzoate, isophorone, acetic acid, lactic acid, and pyruvic acid.

8. The method according to any one of claims 1 to 3, characterized in that, In step S2, the temperature of the desorption treatment is 30 °C - 80 °C, the pressure is 0 - 10 kPa in terms of absolute pressure, and the time is 5 min - 30 min; Preferably, in step S2, the desorption treatment is carried out under stirring conditions, and the stirring rate is 50 rpm - 500 rpm; Preferably, in step S2, the pressure of the desorption treatment is 0 - 5 kPa in terms of absolute pressure.

9. The method according to any one of claims 1-3, characterized in that In step S2, the temperature of the condensation treatment is -60 °C - 10 °C, and the pressure is 0 - 10 bar in terms of gauge pressure; More preferably, the pressure of the condensation treatment is 3 bar - 10 bar in terms of gauge pressure.

10. The method according to any one of claims 1-3, characterized in that, This method is carried out in a sewage treatment device, and the sewage treatment device includes a sewage tank, a desorption unit (2), and a condensation unit (3) connected in sequence. The sewage tank includes a tank body (1), and an atomizing spray unit (4) is provided above the tank body (1). The atomizing particle diameter range of the atomizing spray unit (4) is not greater than 1000 μm, and the atomizing spray unit (4) is used to spray the absorbent droplets onto the sewage (11) in the tank body (1); The desorption unit (2) is also connected to the atomizing spray unit (4) through a recovery pipeline (6). The desorption unit (2) is used to subject the rich liquid oil phase (12) from the tank body (1) to desorption treatment, and recycle the recycled absorbent obtained from the desorption treatment back to the atomizing spray unit (4); The condensation unit (3) is used to condense the rich gas from the desorption unit (2); The method includes: S1: Introduce the sewage into the tank body (1), and spray absorbent droplets onto the sewage (11) through the atomizing spray unit (4) to obtain the rich liquid oil phase (12) and the water phase (11); S2: Introduce the rich liquid oil phase (12) into the desorption unit (2) for desorption treatment to obtain the rich gas and the recycled absorbent; S3: Introduce the rich gas into the condensation unit (3) for condensation treatment to obtain the gaseous light hydrocarbons and the liquid light hydrocarbons.

11. The method according to claim 10, characterized in that, The sewage treatment device further includes a liquid-liquid separator (9) provided between the tank body (1) and the desorption unit (2), and the liquid-liquid separator (9) is also connected to the tank body (1) through a sewage circulation pipeline (10); The method further includes: Before step S2, introduce the rich liquid oil phase (12) into the liquid-liquid separator (9) for liquid-liquid separation treatment to obtain moisture and the rich liquid oil phase (12) with a water content not exceeding 1 wt%, and recycle the moisture back to the tank body (1).

12. A sewage treatment device, characterized in that, It includes a tank body (1), a desorption unit (2), and a condensation unit (3) connected in sequence; The sewage tank includes a tank body (1), and an atomizing spray unit (4) is provided above the tank body (1). The atomizing particle diameter range of the atomizing spray unit (4) is not greater than 1000 μm, and the atomizing spray unit (4) is used to spray absorbent droplets onto the sewage (11) in the tank body (1); The desorption unit (2) is also connected to the atomizing spray unit (4) through a recovery pipeline (6). The desorption unit (2) is used to desorb the rich liquid oil phase (12) from the tank body (1) and recycle the recycled absorbent obtained from the desorption treatment back to the atomizing spray unit (4); The condensation unit (3) is used to condense the rich gas from the desorption unit (2).

13. The device according to claim 12, characterized in that, The sewage treatment device further includes a liquid-liquid separator (9) provided between the tank body (1) and the desorption unit (2), and the liquid-liquid separator (9) is also connected to the tank body (1) through a sewage circulation pipeline (10).

14. The device according to claim 12, characterized in that, The atomizing spray unit (4) includes a plurality of atomizing nozzles (41), and the atomizing nozzles (41) are automatic rotary atomizing nozzles.

15. The device according to claim 12, characterized in that, The spraying direction of the atomizing nozzle (41) is the horizontal direction.

16. The device according to claim 12, characterized in that, The sewage tank is also provided with a VOCs concentration monitor (13), and the VOCs concentration monitor (13) is used to monitor the VOCs concentration at a position 50 mm - 150 mm above the liquid level of the sewage (11) in the tank body (1).

17. The device according to any one of claims 12-16, characterized in that, The tank body (1) is provided with a rich liquid oil phase discharge port, and a filter (14) is provided at the rich liquid oil phase discharge port.

18. The device according to any one of claims 12-16, characterized in that, The sewage tank further includes a tank cover (15), the atomizing spray unit (4) is provided below the tank cover (15), and a clean gas discharge port (16) is provided on the tank cover (15) and / or the side wall of the tank body (1).

19. The device according to any one of claims 12-16, characterized in that, The tank body (1) is connected to the desorption unit (2) through an oil pump (7); And / or, the desorption unit (2) is connected to the condensation unit (3) via a suction pump (8).

20. The device according to any one of claims 12-16, characterized in that, The desorption unit (2) includes a desorption container (21) and a heater (23) for heating the liquid material in the desorption container (21).

21. The device according to any one of claims 12-16, characterized in that The system further includes a product collection unit, which includes a liquid hydrocarbon collection unit (51) and a gaseous hydrocarbon collection unit (52). The liquid hydrocarbon collection unit (51) and the gaseous hydrocarbon collection unit (52) are each independently connected to the condensation unit (3).

22. Use of the sewage treatment method according to claims 1-11 and / or the sewage treatment device according to claims 12-21 in treating sewage.

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