CN112919571B - Air flotation reinforced multistage fiber coalescence oil removal device and method - Google Patents
Air flotation reinforced multistage fiber coalescence oil removal device and method Download PDFInfo
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- C02—TREATMENT OF WATER, WASTE WATER, SEWAGE, OR SLUDGE
- C02F—TREATMENT OF WATER, WASTE WATER, SEWAGE, OR SLUDGE
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- C02F—TREATMENT OF WATER, WASTE WATER, SEWAGE, OR SLUDGE
- C02F1/00—Treatment of water, waste water, or sewage
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Abstract
Provides a method and a device for removing oil by coalescence of air flotation reinforced multistage fibers. The method comprises the following steps: the oily sewage rectified by the rectifying plate passes through an oleophobic fiber demulsification layer to realize physical demulsification of emulsion; the demulsified fluid enters the oleophilic fiber aggregation layer to wet and aggregate the micro oil drops in the aggregation layer; the oil phase from the coalescence layer moves upwards under the drive of buoyancy and bubbles, and meanwhile, oil drops further gather and grow up under the drive of the bubbles and are discharged through a first oil phase discharge port, and other oil phases enter a liquid discharge layer; rely on the capillary repulsion effect in oleophobic fibre drainage layer, oil phase liquid droplet can be caught to the drainage layer front end, gathers and oil the upper end that the oil droplet more easily moved to the drainage layer under the effect of buoyancy and bubble simultaneously, improves the oil phase of drainage layer distributes, promotes the oil phase and flows through second oil phase discharge port. The method and the device can realize deep demulsification, coalescence and separation of the oily sewage and realize efficient and clean treatment of the oily sewage.
Description
Technical Field
The invention belongs to the technical field of heterogeneous separation, and particularly relates to an air-flotation reinforced multistage fiber coalescence deoiling method and device, and more particularly relates to a method and device for efficiently demulsifying, coalescing and separating emulsified oil phase in oily sewage by utilizing an aeration device in cooperation with a tertiary fiber bed of a demulsification layer, a coalescence layer and a drainage layer.
Background
In recent years, with the increasingly prominent problems of water resource shortage and water environment destruction in China and the vigorous development of the petrochemical industry, the treatment of water pollution, the reduction of water resource waste and the efficient development of the treatment of oily sewage are one of the important tasks for environmental protection in China. The floating oil (with the particle size of more than 100 mu m) and the dispersed oil (with the particle size of 20-100 mu m) can be effectively separated by simple mechanical means such as standing because of large particle size. The emulsified oil (with the particle size of 0.1-20 mu m) is small in particle size, so that the system is stable, and the emulsified oil is difficult to separate by a simple mechanical means, so that the efficient separation of the emulsified oil is a key and difficult point in the technical field of oily sewage treatment.
In order to realize the demulsification and separation of the emulsified oily sewage, methods such as adding chemical agents, applying external energy fields, setting coalescence media and the like are generally adopted to accelerate the demulsification and destabilization process. The medium coalescence-separation technology breaks a liquid film between two phases of oil and water by utilizing the wettability of a coalescence medium to the oil phase, accelerates demulsification, promotes coalescence and growth of the oil phase and completes separation. The medium coalescence-separation technology has the characteristics of simple structure, convenience in maintenance, no secondary pollution, capability of recycling an oil phase while realizing oil-water separation and the like, and is valued in the field of oil-water separation, but the prior patent technology is difficult to realize deep demulsification of emulsified oily sewage. Chinese patent CN 111422949A discloses an oil-water separation device, which is characterized in that a plurality of layers of coalescence plates made of polypropylene-based oil balls are arranged to induce the wetting and coalescence of emulsified oil phase droplets so as to realize the separation of an oil phase; chinese patent CN 111348769 a discloses a coalescence degreaser for oil field sewage treatment, which improves the coalescence efficiency by increasing the number of the coalescence corrugated plates arranged under the condition of keeping the cross-sectional area of the water flow channel unchanged. Above patent is through the method that increases single kind coalescence medium quantity, improves the water oil separating effect, but the breakdown of emulsion effect remains to be improved, and too much coalescence medium's setting can lead to device operation pressure drop too high, work efficiency low moreover, can not satisfy high-efficient production requirement.
Chinese patent CN 110902760 a discloses a dirty oil-water separation device and an oil-water separator, which perform oil-water separation treatment on oil-sewage under vacuum condition and guide the flow direction of dirty oil-water. Although the device can effectively reduce the operation pressure drop, improves water oil separating efficiency, nevertheless still be more weak to the throughput of emulsified oil, the device is complicated simultaneously, is unfavorable for the use and the routine maintenance of device, has increased device use cost.
Therefore, the method and the device which can realize deep demulsification and high-efficiency oil-water separation on the emulsified oily sewage and ensure low operation pressure drop and maintenance cost are urgently needed to be developed in the field.
Disclosure of Invention
The invention aims to solve the problems of poor demulsification effect, high operation pressure drop, low separation efficiency and the like in the conventional oil-water separation method and device, and provides a novel method and device for performing oil-water separation by using an aeration device in cooperation with a tertiary fiber bed of a demulsification layer, a coalescence layer and a drainage layer, so that the device can realize deep demulsification of oily sewage, improve coalescence efficiency and reduce the overall pressure drop of the device at low operation cost.
In one aspect, the present invention provides an air flotation reinforced multistage fiber coalescence deoiling device, which is characterized in that the device comprises:
a coalescence tank body 1 which comprises a rectification unit 1-1, a coalescence unit 1-2 and a water outlet unit 1-3 from left to right,
the rectifying unit 1-1 is connected with a liquid inlet 2, and a rectifying plate 3 is arranged in the cavity;
the coalescence unit 1-2 sequentially comprises an emulsion breaking layer 4 positioned at the foremost end of the coalescence unit 1-2, a coalescence layer 5 positioned in the middle section of the coalescence unit and a drainage layer 7 positioned at the rear part of the coalescence unit, wherein a first oil phase discharge port 6 is arranged at the upper part of a separation area between the coalescence layer 5 and the drainage layer 7, a first aeration area 8 is arranged at the lower part of the separation area between the coalescence layer 5 and the drainage layer 7, and a second aeration area 9 is arranged at the lower end of the drainage layer 7;
the upper end of the water outlet unit 1-3 is provided with a second oil phase outlet 11, and the lower end is provided with a water phase outlet 10.
The rectifying plate 3 is selected from one of a porous pipe, a branch pipe, an anti-impact baffle, an inclined plate and a column type blade.
The demulsification layer is a fiber bed layer made of oleophobic fibers with the fiber diameter of 1-10 mu m, and the porosity of the fiber bed layer is 0.75-0.95.
The aggregation layer 5 is made of a mixed-braided stainless steel wire fiber net, the mixed-braided stainless steel wire fiber net is formed by mixing and braiding oleophylic fibers and stainless steel wires, the diameter of the oleophylic fibers is 10-30 mu m, the diameter of the stainless steel wires is 200-230 mu m, and epsilon is set by the aggregation layer 5 with diagonal lines as boundaries1、ε2Two porosities, ∈10.65 to 0.75,. epsilon20.50-0.65, and the volume of the stainless steel wire in the whole bed layer is not more than 10%.
The drainage layer 7 is made of a blended hydrophilic and oleophobic fiber net which is formed by blending hydrophilic and oleophobic fibers and stainless steel wires, the diameter of the hydrophilic and oleophobic fibers is 10-50 mu m, and the diameter of the stainless steel wires is 200-300 μm; the middle part of the porosity of the drainage layer 7 is 0.5-0.7, the porosity is increased in a stepped manner towards two ends, the maximum porosity is 0.7-0.8, the volume of a stainless steel wire in the whole bed layer is not more than 10%, the lower end of the drainage layer is provided with a through air passage 71 perpendicular to the flow direction of fluid, the width d of the air passage is 1-10 mm, and the depth L of the air passage is 1-10 mm250-100 mm, and an arrangement interval L1Is 5 to 10 days.
In another aspect, the present invention provides a method for removing oil by coalescence of air-flotation reinforced multi-stage fibers, comprising the following steps:
(a) oily sewage to be treated enters the coalescence tank body 1 through the liquid inlet 2, and firstly passes through the rectifying plate 3, so that the fluid is uniformly distributed in the flow direction;
(b) introducing the fluid rectified in the step (a) into a demulsification layer 4 to realize physical demulsification of emulsion;
(c) introducing the demulsified fluid from step (b) into the coalescing layer 5;
(d) the oil phase coalesced in step (c) passes above the first aeration zone 8, and a portion of the oil phase is discharged through a first oil phase discharge port 6;
(e) the oil phase which is not discharged in step (d) enters the liquid discharge layer 7, passes through the second aeration zone 9, intermittently flows out from the second oil phase discharge port, and the aqueous phase is continuously discharged through the aqueous phase discharge port 10.
In step (a), the oil concentration in the oil-containing water is not more than 1000mg/L, and the apparent flow velocity of the fluid in the device is less than 0.05 m/s.
The gas flow of the first aeration zone 8 is 0.5-3.0% of the sewage flow, and the diameter of the bubbles is controlled to be 10-100 mu m; the air flow of the second aeration zone (9) is 0.1-1.0% of the sewage flow, and the diameter of the bubbles is controlled to be 10-50 mu m.
The aeration zone is provided with a micro-nano aeration head, and gas can be nitrogen, air or other gases which are easy to prepare is introduced into the gas inlet end of the micro-nano aeration head.
In the method, the uniformly distributed fluid can improve the emulsion breaking and coalescing efficiency of the subsequent steps and improve the utilization rate of the fiber bed layer. Due to the oleophobic characteristic, the oleophobic fiber demulsification layer depends on the collision coalescence principle to achieve the demulsification effect and improve the coalescence efficiency of the subsequent coalescence layer. Due to the oleophylic characteristic, the coalesced oil drops in the oleophylic fiber coalescent layer are difficult to float upwards under the action of buoyancy, so that the oil phase is more uniformly distributed in the longitudinal direction of the coalescent layer, the high-density and uniform oil phase distribution is favorable for capturing the tiny oil drops in the incoming flow, and the coalescing capacity of the device is further improved. The oil phase on the upper part of the coalescence layer can be discharged through the first oil phase discharge port, so that the subsequent treatment capacity is reduced, and the secondary crushing of the coalesced large oil drops in the subsequent flow can be effectively prevented, so that the secondary entrainment of the oil phase is prevented.
The effective benefits are as follows:
the method and the device have the main advantages that:
(1) in the demulsification layer, the micron-sized complex microchannel formed by the oleophobic fibers can greatly increase the collision probability of micro droplets in the oily sewage, realize collision coalescence, and well play the demulsification effect.
(2) In the coalescence layer, the oil phase has lipophilic fibers with good hydrophilicity, the oil phase has higher capturing capacity, the micro oil drops in the oily sewage can be effectively captured, the micro oil drops are promoted to be wetted and coalesced in the coalescence layer, the coalescence oil drops are difficult to float under the action of buoyancy due to the lipophilicity, the oil phase is more uniformly distributed in the coalescence layer in the longitudinal direction, the high-density and uniform oil phase distribution is beneficial to capturing the micro oil drops in the incoming flow, and the coalescence capacity of the device is further improved.
(3) In the drainage layer, the capillary repulsion of oleophobic fibre makes the front end of drainage layer can catch the gathering oil phase liquid drop, because fibrous oleophobic nature, to oil dripping adhere the ability less strongly, gathers and oil to drip and remove to the upper end of drainage layer more easily under the effect of buoyancy, improves the oil phase distribution of drainage layer promotes the oil phase warp the second oil phase discharge port flows, reduces the whole pressure drop of device improves coalescence efficiency.
(4) The aeration zone can drive the coalescent oil phase to float upwards and be discharged through the first oil phase discharge port, so that the oil phase distribution in the liquid discharge layer is improved, and the pressure drop of the device is reduced; on the other hand, the existence of the micro-bubbles can promote the collision coalescence of oil drops and improve the coalescence efficiency of the device.
(5) The multistage fiber bed layer is matched with the aeration zone, so that the separation efficiency of the device is improved, the separation efficiency of a single device can reach 98 percent, and the pressure drop of the device is reduced by 42 percent on the same scale under the condition of the same separation efficiency; meanwhile, the invention has simple flow and convenient operation, adopts a pure physical coalescence oil removal mode, avoids secondary pollution, can recycle the separated oil phase, can save a large amount of expenses for enterprises, creates considerable economic value, and is suitable for being widely popularized in the field of oily sewage treatment.
Drawings
The accompanying drawings are included to provide a further understanding of the invention, and are incorporated in and constitute a part of this specification to further illustrate the invention and not limit the invention.
In the drawings, the components are not necessarily drawn to scale.
FIG. 1 is a schematic diagram of an air flotation enhanced multistage fiber coalescing de-oiling device according to a preferred embodiment of the present invention;
FIG. 2 is a schematic cross-sectional view of a coalesced layer in an oil removing apparatus according to a preferred embodiment of the present invention;
fig. 3 is a schematic sectional view of a drainage layer in the oil removing device according to a preferred embodiment of the present invention.
Wherein the reference numerals denote the following devices and internals, respectively:
1, a coalescence tank body; 1-1 a rectifying unit; 1-2 coalescing units; 1-3 water outlet units; 2, a liquid inlet; 3, a rectifying plate; 4 a demulsifying layer; 5 a polymeric layer; 6 a first oil phase discharge port; 7, draining the liquid layer; 8 a first aeration zone; 9 a second aeration zone; 10 water phase discharge port; 11 a second oil phase discharge port; 71 air passages.
Detailed Description
In order to make the technical problems, technical solutions and advantageous effects solved by the present invention more clearly apparent, the present invention is further described in detail below with reference to the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are merely illustrative of the invention and are not intended to limit the invention.
After extensive and intensive research, the inventor of the present application finds that the coalescence mode of the tiny oil drops mainly includes collision coalescence and wetting coalescence, so that the probability of the two coalescence modes is increased, and the coalescence-separation efficiency of the device can be improved. The demulsification layer made of the nanoscale oleophobic fibers is provided with a plurality of micro-nano channels, and the existence of the channels can increase the collision probability of emulsified oil drops, enhance the collision coalescence of the oil drops and achieve the demulsification effect of oily sewage; the coalescence layer is made of oleophilic fibers, and the oleophilic fibers can effectively capture tiny oil drops in sewage and enhance the wetting coalescence of the oil drops; the liquid discharging layer made of the oleophobic fiber is arranged behind the aggregation layer, larger oil drops can be captured by means of the capillary repulsion action of the front end, micro oil drops in fluid are further adsorbed by means of the captured oil drops, meanwhile, the distribution of oil phases in a bed layer is improved, and the operation pressure drop of the device is reduced. The existence of the micro bubbles can promote the floating of oil drops in the fluid to be discharged through the oil phase discharge port, improve the distribution of the oil phase in the device and reduce the operation pressure drop of the device; meanwhile, the collision probability of the oil drops can be increased in the floating process, and the collision coalescence of the oil drops is realized. The present invention has been completed based on the above conception and finding.
FIG. 1 is a schematic diagram of an air flotation reinforced multistage fiber coalescence degreasing device according to a preferred embodiment of the invention. From left to right, comprises a rectifying unit 1-1, a coalescing unit 1-2 and a water outlet unit 1-3. The rectifying unit 1-1 is connected with a liquid inlet 2, and a rectifying plate 3 is arranged in the cavity. The coalescence unit 1-2 comprises a demulsification layer 4, a coalescence layer 5, a liquid drainage layer 7, a first oil phase discharge port 6, a first aeration area 8 and a second aeration area 9, wherein the demulsification layer 4 is positioned at the foremost end of the coalescence unit 1-2 and has the function of physical demulsification, the coalescence layer 5 is positioned in the middle section of the coalescence unit 1-2, micro droplets are aggregated by the coalescence layer 5 to form large droplets, the first oil phase discharge port 6 is positioned at the upper part of the interval between the coalescence layer 5 and the liquid drainage layer 7, the first aeration area 8 is arranged behind the coalescence layer 5, and the second aeration area 9 is arranged at the lower end of the liquid drainage layer 7. The water outlet unit 1-3 is connected with a second oil phase outlet 11 and a water phase outlet 10, the second oil phase outlet 11 is positioned at the upper end of the water outlet unit (1-3), and the water phase outlet 10 is positioned at the lower end of the water outlet unit (1-3).
Fig. 2 is a schematic cross-sectional view of a coalesced layer in an oil removing apparatus according to a preferred embodiment of the present invention. The aggregation layer 5 is made of a mixed-braided stainless steel wire fiber net, the mixed-braided stainless steel wire fiber net is formed by mixing and braiding oleophylic fibers and stainless steel wires, the diameter of the oleophylic fibers is 10-30 mu m, the diameter of the stainless steel wires is 200-230 mu m, and epsilon is set by the aggregation layer 5 with diagonal lines as boundaries1、ε2Two porosities, ∈10.65 to 0.75,. epsilon20.50-0.65, and the volume of the stainless steel wire in the whole bed layer is not more than 10%. Under the combined action of capillary force and fiber adsorption force, a large amount of oil phase is gathered at the front end of the coalescence layer, the oil phase moves upwards under the action of buoyancy, and the density of the oil phase at the upper end of the coalescence layer is higher; compared with the prior art, the oil phase density at the lower end and the rear end of the bed layer is smaller, the oil phase coalescence capability is weaker, and in order to improve the fiber utilization rate of the bed layer and reduce the operation pressure drop, the porosity of the front end and the upper end of the bed layer is set to be larger, and the porosity of the rear end and the lower end of the bed layer is set to be smaller.
Fig. 3 is a schematic sectional view of a drainage layer in the oil removing device according to a preferred embodiment of the present invention. The drainage layer 7 is made of a blended hydrophilic and oleophobic fiber net which is formed by blending hydrophilic and oleophobic fibers and stainless steel wires, wherein the diameter of the hydrophilic and oleophobic fibers is 10-50 mu m, and the diameter of the stainless steel wires is 200-300 mu m. In order to facilitate the air bubbles to enter the liquid drainage layer and promote the coalescent oil phase to move upwards, the bottom end of the liquid drainage layer is provided with an air passage which simultaneously increases the porosity of the upper end and the lower end. The middle part of the porosity of the liquid drainage layer 7 is 0.5-0.7, the liquid drainage layer is increased in a gradient mode towards two ends, the maximum porosity is 0.7-0.8, the volume of a stainless steel wire in the whole bed layer is not more than 10%, the lower end of the liquid drainage layer is perpendicular to the flow direction of fluid and is provided with a penetrating type air channel 71, the width d of the air channel is 1-10 mm, the depth L2 of the air channel is 50-100 mm, and the arrangement distance L1 is 5-10 d.
The method for removing oil by coalescence of air flotation reinforced multistage fibers comprises the following steps:
(a) oily sewage to be treated enters the coalescence tank body 1 through the liquid inlet 2, firstly passes through the rectifying plate 3, and under the action of the rectifying plate (3), fluid is uniformly distributed in the flowing direction;
(b) introducing the fluid rectified in the step (a) into a demulsification layer 4, wherein a complex micro-channel is formed by micron-sized oleophobic fibers, so that the collision probability of micro oil drops in the oily sewage is greatly increased, the micro oil drops are promoted to collide and coalesce into large oil drops, the stable state of the oily sewage is destroyed, and the physical demulsification of the emulsion is realized;
(c) introducing the demulsified fluid in the step (b) into the agglomeration layer 5, wherein the oleophilic fibers with good hydrophilicity and wettability to the oil phase have higher capture capacity to the oil phase, and can effectively capture micro oil drops in the oily sewage to promote the micro oil drops to be wetted and agglomerated in the agglomeration layer;
(d) when the oil phase coalesced in the step (c) passes above the first aeration zone 8, the oil phase moves upwards under the drive of buoyancy and bubbles, meanwhile, the micro oil drops further coalesce and grow up under the action of the bubbles, and the grown oil phase is discharged through a first oil phase outlet 6;
(e) oil phase that does not discharge gets into drainage 7 in step (d), relies on the capillary repulsion of the fine and close oleophobic fibre, and the front end of drainage 7 can catch the gathering oil phase liquid droplet, because the oleophobic nature of fibre, it is weaker to the adhesion ability of oil droplet, gathers and oil droplet and removes to the upper end of drainage under the effect of buoyancy more easily, and the bubble that second aeration zone 9 produced also can promote the oil phase come-up, improves the oil phase distribution of drainage, promotes the oil phase warp the outflow of second oil phase discharge port, reduces the whole pressure drop of device, improves coalescence efficiency.
In step (a), the oil concentration in the oil-containing water is not more than 1000mg/L, and the apparent flow velocity of the fluid in the device is less than 0.05 m/s. The air flow of the first aeration zone 8 is 0.5-3.0% of the sewage flow, and the diameter of the bubbles is controlled to be 10-100 mu m; the air flow of the second aeration zone 9 is 0.1-1.0% of the sewage flow, and the diameter of the bubbles is controlled to be 10-50 mu m. The aeration zone is provided with a micro-nano aeration head, and gas can be nitrogen, air or other gases which are easy to prepare is introduced into the gas inlet end of the micro-nano aeration head.
Examples
The invention is further illustrated below with reference to specific examples. It is to be understood, however, that these examples are illustrative only and are not to be construed as limiting the scope of the present invention. Test methods in which specific conditions are not specified in the following examples are generally carried out under conventional conditions or under conditions recommended by the manufacturer. All percentages and parts are by weight unless otherwise indicated.
Example 1:
in this example, the emulsion to be separated was obtained from a laboratory homemade emulsion. In the experiment, diesel oil and tap water are respectively conveyed into an emulsifying kettle in proportion by a peristaltic pump and a metering pump, and the emulsified liquid with uniform droplet size distribution is obtained by continuously stirring the emulsifying kettle at the rotating speed of 900rpm for 45 min.
The particle size distribution of the emulsified droplets was measured using an optical microscope and Image-Pro Plus software. The measurement result shows that the average grain size of the oil drops at the inlet of the coalescer is 10.8 mu m, and the grain size of more than 85 percent of the oil drops is within the range of 3.0-15.0 mu m. The oil concentration at the inlet of the coalescer is kept at 600mg/L in the experiment, and the oil concentration in the water is measured by an infrared spectrophotometer according to the national environmental protection standard HJ 637-2012.
In the experiment, the gas flow rate of the first aeration zone is 5 x 10-4L/s, and the diameter of the bubbles is controlled to be 20 mu m; the gas flow rate of the second aeration zone is 1 x 10-5L/s, controlling the diameter of the bubbles to be 10 mu m; the oily sewage flows through the rectifying plate, the demulsification layer, the aggregation layer and the liquid discharge layer in sequence at an apparent flow velocity of 0.015 m/s; the rectifying plate is an inclined plate type, and the porosity of the demulsification layer is 0.8; epsilon in the coalescence layer1Is 0.75,. epsilon2Is 0.65; the middle part of the porosity of the drainage layer is 0.6, the drainage layer is increased in a step shape towards two ends, and the maximum porosity is 0.75; the width d of the air passage is 5mm, and the depth L of the air passage2Is 100mm, and is arranged at a spacing L1Is 50 mm. The oil phase is intermittently discharged through an oil phase discharge port, the water phase is continuously discharged through a water phase discharge port, the separation efficiency reaches 97.6 percent, the pressure drop is 920pa, the oil content of the water phase discharge port of the coalescer is lower than 20mg/L, and the relevant discharge standard of the sewage in China is reached.
Example 2:
in this example, the emulsion to be separated was obtained from a laboratory-made emulsion, and the particle size and concentration detection methods were the same as those in example 1. Respectively conveying isooctane and tap water into a static mixer in parallel through a peristaltic pump and a metering pump to prepare O/W emulsion, and enabling an oil phase to form emulsion with the average particle size of about 10 mu m (more than 85%) in water after the oil phase and the water phase pass through the mixer.
In the experiment, the oil concentration at the inlet of the coalescer is kept at 300mg/L, and the gas flow of the first aeration zone is kept at 5 x 10-4L/s, and the diameter of the bubbles is controlled to be 20 mu m; the gas flow rate of the second aeration zone is 1 x 10-5L/s, controlling the diameter of the bubbles to be 10 mu m; the oily sewage flows through the rectifying plate, the demulsification layer, the aggregation layer and the liquid discharge layer in sequence at an apparent flow velocity of 0.01 m/s; the rectifying plate is an inclined plate type, and the porosity of the demulsification layer is 0.8; epsilon in the coalescence layer1Is 0.65,. epsilon2Is 0.50; the middle part of the porosity of the drainage layer is 0.6, the drainage layer is increased in a step shape towards two ends, and the maximum porosity is 0.75; the width d of the air passage is 5mm, and the depth L of the air passage2Is 100mm, and is arranged at a spacing L1Is 50 mm. The liquid at the water phase discharge port is detected, the separation efficiency reaches 98.7 percent, the pressure drop is 980pa, the oil content at the water phase discharge port of the coalescer is lower than 20mg/L, and the relevant discharge standard of the sewage in China is reached.
Example 3:
in this example, the liquid to be separated is oily sewage in 908# sewage pool of a certain organic silicon production enterprise in China, and since the sample is obtained after the sedimentation treatment in the sedimentation tank, the concentration of petroleum in the sewage is not more than 600mg/L at most, but the concentration fluctuation is large, the dispersed particle size is small, and the organic waste water belongs to a highly emulsified state, and table 1 is the basic characteristic of the organic waste water.
TABLE 1 basic characteristics of the organosilicon Process waste Water
The first aeration zone gas stream when the oil concentration at the coalescer inlet was 236mg/LThe amount is 5 x 10-4L/s, and the diameter of the bubbles is controlled to be 20 mu m; the gas flow rate of the second aeration zone is 1 x 10-5L/s, controlling the diameter of the bubbles to be 10 mu m; the oily sewage flows through the rectifying plate, the demulsification layer, the aggregation layer and the liquid discharge layer in sequence at an apparent flow velocity of 0.012 m/s; the rectifying plate is an inclined plate type, and the porosity of the demulsification layer is 0.8; epsilon in the coalescence layer1Is 0.75,. epsilon2Is 0.5; the middle part of the porosity of the drainage layer is 0.6, the drainage layer is increased in a step shape towards two ends, and the maximum porosity is 0.75; the width d of the air passage is 5mm, and the depth L of the air passage2Is 100mm, and is arranged at a spacing L1Is 50 mm. The oil concentration of the water phase discharge outlet after coalescence and separation can be reduced to 9.5mg/L, and the separation efficiency is 96%. Meanwhile, during the experiment, 6L of siloxane oil can be recycled every day, so that the oil phase is recycled while the content of the emulsified oil phase in the wastewater is reduced.
Claims (6)
1. An air flotation reinforced multistage fiber coalescence deoiling device is characterized by comprising:
a coalescence tank body (1) which comprises a rectification unit (1-1), a coalescence unit (1-2) and a water outlet unit (1-3) from left to right,
the rectifying unit (1-1) is connected with a liquid inlet (2), and a rectifying plate (3) is arranged in the cavity;
the coalescence unit (1-2) sequentially comprises a demulsification layer (4) positioned at the foremost end of the coalescence unit, a coalescence layer (5) positioned at the middle section of the coalescence unit and a drainage layer (7) positioned at the rear part of the coalescence unit, a first oil phase discharge port (6) is arranged at the upper part of a separation area between the coalescence layer (5) and the drainage layer (7), a first aeration area (8) is arranged at the lower part of the separation area between the coalescence layer (5) and the drainage layer (7), and a second aeration area (9) is arranged at the lower end of the drainage layer (7);
the upper end of the water outlet unit (1-3) is provided with a second oil phase outlet (11), and the lower end of the water outlet unit is provided with a water phase outlet (10);
the demulsification layer is a fiber bed layer made of oleophobic fibers with the diameter of 1-10 mu m, and the porosity of the fiber bed layer is 0.75-0.95;
the agglomeration layer (5) is formed by mixingThe stainless steel wire fiber net is formed by weaving lipophilic fibers and stainless steel wires in a mixed mode, the diameter of the lipophilic fibers is 10-30 mu m, the diameter of the stainless steel wires is 200-230 mu m, and the aggregation layer (5) is provided with epsilon in a manner of taking diagonal lines as boundaries1、ε2Two porosities, ∈1Is the porosity of the diagonal front bed, ε2Is the porosity of the diagonal rear bed, epsilon10.65 to 0.75,. epsilon20.50-0.65 percent, and the volume of the stainless steel wire in the integral bed layer is not more than 10 percent;
the drainage layer (7) is made of a blended hydrophilic and oleophobic fiber net which is formed by blending hydrophilic and oleophobic fibers and stainless steel wires, the diameter of the hydrophilic and oleophobic fibers is 10-50 mu m, and the diameter of the stainless steel wires is 200-300 mu m; the middle part of the porosity of the drainage layer (7) is 0.5-0.7, the porosity is increased in a stepped manner to two ends, the maximum porosity is 0.7-0.8, the volume of a stainless steel wire in the whole bed layer is not more than 10%, the lower end of the drainage layer is perpendicular to the flow direction of fluid and is provided with a through air passage (71), the width d of the air passage is 1-10 mm, and the depth L of the air passage is 1-10 mm250-100 mm, and an arrangement interval L1Is 5 to 10 days.
2. The apparatus according to claim 1, wherein the rectifying plate (3) is one selected from a perforated pipe, a branched pipe, an impingement baffle, an inclined plate, and an inline vane.
3. An air flotation enhanced multistage fiber coalescence degreasing method using the apparatus of claim 1, characterized in that the method comprises the following steps:
(a) oily sewage to be treated enters the coalescence tank body (1) through the liquid inlet (2), and firstly passes through the rectifying plate (3) to ensure that the fluid is uniformly distributed in the flowing direction;
(b) introducing the fluid rectified in the step (a) into a demulsification layer (4) to realize physical demulsification of the emulsion;
(c) introducing the fluid demulsified in the step (b) into the aggregation layer (5);
(d) the oil phase after being coalesced in the step (c) passes above the first aeration zone (8), and a part of the oil phase is discharged through a first oil phase discharge port (6);
(e) the oil phase which is not discharged in the step (d) enters a liquid discharge layer (7), passes through a second aeration zone (9), intermittently flows out from a second oil phase discharge port, and the water phase is continuously discharged through a water phase discharge port (10).
4. A method according to claim 3, wherein in step (a) the oil concentration in the oily water is not more than 1000mg/L and the superficial flow velocity of the fluid in the apparatus is less than 0.05 m/s.
5. A method according to claim 3, characterized in that the gas flow rate of the first aeration zone (8) is 0.5-3.0% of the sewage flow rate, and the diameter of the gas bubbles is controlled to be 10-100 μm; the air flow of the second aeration zone (9) is 0.1-1.0% of the sewage flow, and the diameter of the bubbles is controlled to be 10-50 mu m.
6. The method as claimed in claim 3, wherein the first and second aeration zones are provided with micro-nano aeration heads, and gas is introduced into the inlet ends of the micro-nano aeration heads, and the gas is selected from one of nitrogen and air.
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| CN114409169A (en) * | 2022-01-27 | 2022-04-29 | 陕西华祥能源科技集团有限公司 | Gas station phenol water oil removal evaporation treatment device and process |
| CN114702095B (en) * | 2022-03-10 | 2023-07-25 | 华东理工大学 | Circulating oil-water separation system and method for coupling segmented fiber particles with microbubbles |
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| CN115557631A (en) * | 2022-09-15 | 2023-01-03 | 华东理工大学 | Oil-water separation device and method integrating cyclone, air flotation and medium coalescence |
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| CN2091706U (en) * | 1991-05-13 | 1992-01-01 | 宜兴市高塍水处理工程研究所 | Coalescence-type separator of oil from water |
| CN2672039Y (en) * | 2004-01-12 | 2005-01-19 | 大庆油田有限责任公司 | Coalescence gas float oil removing device |
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| Publication number | Priority date | Publication date | Assignee | Title |
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| CN2091706U (en) * | 1991-05-13 | 1992-01-01 | 宜兴市高塍水处理工程研究所 | Coalescence-type separator of oil from water |
| CN2672039Y (en) * | 2004-01-12 | 2005-01-19 | 大庆油田有限责任公司 | Coalescence gas float oil removing device |
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