阅读说明：本技术 一种用于油水分离的多孔纤维的制备方法及应用 (Preparation method and application of porous fiber for oil-water separation ) 是由 杨丽 孙杰 任鹏飞 于 2019-08-27 设计创作，主要内容包括：本发明公开了一种用于油水分离的多孔纤维的制备方法及由该方法制备的多孔纤维,包括以下步骤：S1.对包含聚丙烯、聚乙烯、稀释剂和成核剂的混合物进行纺丝处理,得到初生纤维；S2.对所述初生纤维进行冷却处理,得到纤维长丝；S3.对所述纤维长丝进行萃取处理,得到所述多孔纤维。本发明方法工艺简便,生产路径短,根据本发明的方法制备的多孔纤维孔径适中、机械强度高、分离性能优良,应用于油水分离中,分离效率高。本发明还提供了一种用于油水分离的装置,结构简单,消耗动力少,无需投加任何药剂,就能对污水中的油污起到较好的去除效果,且污染较低,在含油污水处理领域具有良好的应用前景。(The invention discloses a preparation method of porous fiber for oil-water separation and porous fiber prepared by the method, which comprises the following steps: s1, spinning a mixture containing polypropylene, polyethylene, a diluent and a nucleating agent to obtain nascent fiber; s2, cooling the nascent fiber to obtain a fiber filament; and S3, extracting the fiber filaments to obtain the porous fiber. The method has simple process and short production path, and the porous fiber prepared by the method has moderate aperture, high mechanical strength and excellent separation performance, is applied to oil-water separation, and has high separation efficiency. The invention also provides a device for oil-water separation, which has the advantages of simple structure, less power consumption, better removal effect on oil stains in sewage without adding any medicament, lower pollution and good application prospect in the field of oily sewage treatment.)

1. A preparation method of porous fiber for oil-water separation comprises the following steps:

s1, spinning a mixture containing polypropylene, polyethylene, a diluent and a nucleating agent to obtain nascent fiber;

s2, cooling the nascent fiber to obtain a fiber filament;

and S3, extracting the fiber filaments to obtain the porous fiber for oil-water separation.

2. The method for preparing a composite material according to claim 1, wherein the step S1 includes:

1A, melting and defoaming a mixture containing polypropylene, polyethylene, a diluent and a nucleating agent to obtain a spinning solution;

and 1B, conveying the spinning solution to a spinning nozzle, and extruding through the spinning nozzle to obtain nascent fibers.

3. The method according to claim 1 or 2, wherein in the mixture, the polypropylene accounts for 17 to 85.5 mass percent, the polyethylene accounts for 1 to 13.5 mass percent, the nucleating agent accounts for 0.1 to 5 mass percent, and the balance is the diluent.

4. The method according to any one of claims 1 to 3, wherein the temperature of the melting treatment is 175-230 ℃ and the time is 0.5-3 h; the time of the defoaming treatment is 0.5-3 h.

5. The production method as claimed in any one of claims 1 to 4, wherein the spinneret has a hole diameter of 0.1 to 5mm and a temperature of 140 ℃ to 180 ℃.

6. The production method according to any one of claims 1 to 5, wherein the as-spun fiber is subjected to a cooling treatment by passing through at least three stages of coagulation baths in the step S2; preferably, the as-spun fiber is first cooled through a primary coagulation bath at 100-120 ℃, then through a secondary coagulation bath at 60-80 ℃, and finally through a tertiary bath at 10-30 ℃ to produce the fiber filament.

7. The preparation method according to any one of claims 1 to 6, wherein the medium of the primary coagulation bath is a glycerol, polyethylene glycol or glyceryl triacetate solution with a mass concentration of 10 to 100%; and/or the medium of the secondary coagulation bath is deionized water; and/or the medium of the tertiary coagulation bath is deionized water.

8. The production method according to any one of claims 1 to 7, wherein the step S3 includes: placing the fiber filament into an extracting agent for extraction or placing the fiber filament into a plurality of extracting agents for sequential extraction; and/or the total extraction time is 3-48 h.

9. The method of any one of claims 1-8, wherein the extractant comprises at least one of a ketone, an alcohol, and an alkane, preferably at least one of acetone, methanol, ethanol, isopropanol, n-hexane, and cyclohexane.

10. The porous fiber for oil-water separation prepared by the method according to any one of claims 1 to 9, having a diameter of 0.1 to 5mm and a specific surface area of 19.0 to 29.5m²/g。

11. Use of the porous fiber for oil-water separation prepared by the method according to any one of claims 1 to 9 or the porous fiber for oil-water separation according to claim 10 in oil-water separation, comprising passing oily sewage through the porous fiber to separate an oil phase and a water phase therein.

12. An apparatus for oil-water separation, comprising:

a liquid storage tank for storing oily sewage;

a coalescer connected to the liquid tank and filled with the porous fiber prepared by the method according to any one of claims 1 to 9 or the porous fiber of claim 10 for receiving the oily wastewater from the liquid tank and treating the same to separate an oil phase and a water phase therein;

a water production tank connected to said coalescer for receiving the aqueous phase from said coalescer;

an oil collection tank connected to the coalescer for receiving the oil phase from the coalescer.

Technical Field

The invention relates to a preparation method of porous fiber for oil-water separation, a porous fiber material prepared by the method, application of the porous fiber material in oil-water separation, and a device for oil-water separation, belonging to the technical field of water treatment.

Background

Oil pollution, a common pollution, is extremely harmful to environmental protection and ecological balance. The range of producing the oily sewage is wide, and the oily sewage is produced in the processes of petroleum exploitation, petroleum refining, petrochemical industry, oil storage and transportation and the like. The oil-containing sewage in China has extremely high yield, more than 30 hundred million tons of oil-containing sewage are generated every year in oil fields and oil refining industries, the oil-containing sewage is one of the industrial waste water which is difficult to treat at present, and along with the requirement on environmental protection and the gradual strictness of energy conservation and consumption reduction, the oil concentration of the discharged sewage specified in the comprehensive sewage discharge standard (GB 8978-.

The coalescence-separation method is a physical oil-removing method, integrates gravity separation and coalescence technologies, and utilizes the characteristic of oil-water density difference to realize the separation process. The coalescence separator has the advantages of low power consumption, high separation efficiency, large operation elasticity and the like, when oily sewage passes through the coalescence separator, oil drops interact with the coalescence material, due to lipophilicity of the surface of the material, the oil drops and the surface of the material form a continuous oil film with a certain thickness, when subsequent oil drops pass through the surface, a liquid-sandwiched layer is formed between the oil drops and the film, the liquid film of the liquid drops is gradually deformed and thinned in the liquid discharging process, the liquid film is broken when reaching a critical value, the two liquid drops are fused and grow up, the small oil drops are gradually aggregated into large oil drops, and along with the traction force of water flow, the large oil drops break away from the adsorption of the coalescence material to realize falling and enter an oil layer under the action of buoyancy to. The technical key of the coalescence method for removing oil is a coalescence material which can be divided into a porous material, a fiber material, a granular material and the like, wherein the fiber material can be made into a material with a smaller diameter and a larger surface area, and the coalescence material has obvious oil removing effect.

The coalescence process mainly depends on the blocking and diffusion effects, and oil drops can be captured by the material under the action of Van der Waals attractive force only when moving to the surface close to the material, so that the action is only tied to the outer surface, the larger the outer surface, the higher the probability that the oil drops are close to the material and attached to the material, the more remarkable influence of the surface area of the material on the coalescence effect of the oil drops is, the surface area of the fiber material on the smooth surface can be improved by adopting a method of reducing the diameter, but the actual operation is greatly difficult due to the excessively small diameter of the coalescence material, and therefore, the more ideal method is to increase the roughness of the surface of the material so as to achieve the purpose of.

Disclosure of Invention

The invention aims to provide a preparation method of porous fiber for oil-water separation according to the defects in the prior art, oleophylic resin is made into a fiber material with a porous surface by a thermal induced phase separation method (TIPS), and the roughness and the surface area of the surface are increased.

According to an aspect of the present invention, there is provided a method for preparing porous fiber for oil-water separation, comprising the steps of:

s1, spinning a mixture containing polypropylene, polyethylene, a diluent and a nucleating agent to obtain nascent fiber;

s2, cooling the nascent fiber to obtain a fiber filament;

and S3, extracting the fiber filaments to obtain the porous fiber for oil-water separation.

According to some embodiments of the invention, the step S1 includes:

1A, melting and defoaming a mixture containing polypropylene, polyethylene, a diluent and a nucleating agent to obtain a spinning solution;

and 1B, conveying the spinning solution to a spinning nozzle, and extruding through the spinning nozzle to obtain nascent fibers.

According to a preferred embodiment of the present invention, in the mixture, the polypropylene accounts for 17 to 85.5 mass%, the polyethylene accounts for 1 to 13.5 mass%, the nucleating agent accounts for 0.1 to 5 mass%, and the balance is the diluent. The fiber prepared in the mass ratio range has good mechanical property and uniform surface pore distribution.

According to a preferred embodiment of the present invention, the polypropylene resin has a melt index of 0.1-100g/10min, and the polypropylene resin has good flowability, processability and mechanical properties in the melt index range, wherein the melt index is measured at a temperature of 230 ℃ and a load weight of 2.16 kg.

According to a preferred embodiment of the invention, the polyethylene is a high density polyethylene having a molecular weight of 40000 to 100000.

According to a preferred embodiment of the present invention, the diluent includes at least one of vegetable oil, liquid paraffin and diphenyl ether.

According to a preferred embodiment of the present invention, the vegetable oil comprises at least one of peanut oil, castor oil and soybean oil.

According to a preferred embodiment of the present invention, the nucleating agent comprises at least one of adipic acid, benzoic acid, pimelic acid and dibenzyl sorbitol.

According to the preferred embodiment of the invention, the temperature of the melting treatment is 175-230 ℃, and the time is 0.5-3 h; the time of the defoaming treatment is 0.5-3 h.

According to a preferred embodiment of the present invention, the step 1A may be performed as follows: adding polypropylene, polyethylene, a diluent and a nucleating agent into a spinning kettle with a stirring device to obtain a mixture, heating to 175-230 ℃, stirring for 0.5-3h under the condition of introducing nitrogen, and uniformly mixing; and after stirring is stopped, standing and defoaming for 0.5-3h to obtain the spinning solution.

According to some embodiments of the invention, the spinneret has an aperture of 0.1 to 5mm and a temperature of 140 ℃.

According to a preferred embodiment of the present invention, the step 1B may be performed as follows: filtering the spinning solution, then conveying the filtered spinning solution to a spinning nozzle by using a metering pump, and extruding the spinning solution through the spinning nozzle at a constant speed to obtain nascent fiber.

According to some embodiments of the invention, the as-spun fiber is subjected to a cooling treatment in step S2 by passing through at least three stages of coagulation baths; preferably, the primary fiber is firstly cooled by staying in a primary coagulation bath at 100-120 ℃ for 5-20s, then cooled by staying in a secondary coagulation bath at 60-80 ℃ for 1-20s, and finally cooled by staying in a tertiary coagulation bath at 10-30 ℃ for 1-20s to prepare the fiber filament.

According to a preferred embodiment of the invention, the medium of the primary coagulation bath is a glycerol, polyethylene glycol or glyceryl triacetate solution with a mass concentration of 10-100%; and/or the medium of the secondary coagulation bath is deionized water; and/or the medium of the tertiary coagulation bath is deionized water. The coagulation bath and the diluent are dissolved and exchanged during the forming of the nascent fiber, so that the generation of a compact skin layer is avoided, and a large number of micropores can be generated on the surface of the fiber.

And after water bath treatment, winding and collecting the fiber filaments by using a traction wheel.

According to the invention, as-spun fibers are cooled and solidified by three different coagulation baths, the internal stress of the fibers can be reduced to the greatest extent, the phenomena of stress cracking, buckling deformation and the like are prevented, and the mechanical and thermal properties of the fibers are improved.

According to some embodiments of the invention, the step S3 includes: placing the fiber filament into an extracting agent for extraction or placing the fiber filament into a plurality of extracting agents for sequential extraction; and/or the total extraction time is 3-48 h.

According to a preferred embodiment of the present invention, the extractant comprises at least one of a ketone, an alcohol and an alkane, preferably at least one of acetone, methanol, isopropanol, n-hexane and cyclohexane, preferably at a concentration of more than 95%.

After extraction by the extractant, the diluent in the fiber filament can be separated and removed, so that pores are formed on the surface of the fiber, and the surface roughness and the surface area of the fiber are increased.

According to some embodiments of the invention, the method further comprises the steps of:

and S4, drying the prepared porous fiber for 12-24h, and removing the water on the surface to obtain the porous fiber.

According to another aspect of the present invention, there is also provided a porous fiber having a diameter of 0.1 to 5mm and a specific surface area of 19.0 to 29.5m, prepared according to the above method²/g。

According to another aspect of the present invention, there is also provided a use of the above porous fiber for oil-water separation, comprising passing oily sewage through the porous fiber to separate an oil phase and a water phase therein.

The porous fiber is an oleophilic material, when oily sewage passes through the porous fiber, oil drops in the sewage are coalesced on the surface of the fiber due to different affinities of an oil phase and a water phase to the fiber, so that the oil drops are changed from small to large, the oil drops after being changed in size float up due to smaller density, and further the separation of the oil phase and the water phase is realized.

According to another aspect of the present invention, there is also provided an apparatus for oil-water separation, including:

a liquid storage tank for storing oily sewage;

a coalescer connected to said tank and filled with said porous fiber for receiving and treating oily wastewater from said tank to separate oil and water phases therein;

a water production tank connected to said coalescer for receiving the aqueous phase from said coalescer;

an oil collection tank connected to the coalescer for receiving the oil phase from the coalescer.

According to some embodiments of the invention, the porous fibers are packed in a bed of the coalescer by layered compaction at a packing volume ratio of 1/2.

According to a preferred embodiment of the present invention, the coalescer is provided with a sewage inlet, a water phase outlet and an oil phase outlet. In some specific embodiments, the oil phase outlet is disposed in an upper portion of the coalescer, and the water phase outlet is disposed in a sidewall of the coalescer.

According to a preferred embodiment of the invention, the apparatus further comprises a sewage tank arranged between the liquid reservoir and the coalescer, the sewage tank being provided with a sewage inlet communicating with the liquid reservoir via a pipe, a sewage outlet communicating with the inlet of the coalescer via a pipe, and a gas inlet, for receiving sewage from the liquid reservoir and conveying it to the coalescer.

According to a preferred embodiment of the present invention, the apparatus further comprises a sewage pump disposed on the pipe between the liquid tank and the sewage tank, for pumping the sewage in the liquid tank into the sewage tank.

According to a preferred embodiment of the invention, the apparatus further comprises a gas source connected to the gas inlet of the waste tank for supplying gas into the waste tank to propel waste into the coalescer. In some embodiments, the gas source is a nitrogen gas cylinder. The air source is connected with the sewage tank through a pipeline, and a pressure stabilizing valve is arranged on the pipeline.

According to a preferred embodiment of the present invention, the apparatus further comprises a flow regulating valve, a flow meter and a feed pump arranged in sequence on the pipe between the sewage tank and the coalescer.

According to a preferred embodiment of the invention, the water production tank communicates with the water phase outlet of the coalescer by means of a conduit, and the oil collection tank communicates with the oil phase outlet of the coalescer by means of a conduit.

The working process and the principle of the device for oil-water separation are as follows:

pumping oily sewage in the liquid storage tank into a sewage tank through a sewage pump, pumping liquid in the sewage tank into a coalescer through a feeding pump, and controlling the water inlet flow within 0.1-0.5m3/h by adjusting a flow regulating valve; the oil phase in the sewage is slowly attached to the surface of the porous fiber and then is gathered to form oil drops, the large-particle oil drops are carried away from the surface of the fiber by the water phase and enter the oil collecting tank through the oil phase outlet, and the water phase without the oil phase enters the water producing tank through the water phase outlet. Preferably, the temperature of the contaminated water is between 30 and 50 ℃.

According to another aspect of the invention, a method for oil-water separation by using the device is provided, which comprises the following steps:

(1) the porous fibers are packed into a bed layer of a coalescer in a layered and compacted mode, and the packing volume ratio is 1/2;

(2) pumping the oily sewage with the temperature of 30-50 ℃ in the liquid storage tank into a sewage tank through a sewage pump;

(3) opening a flow regulating valve, a flowmeter, a pressure stabilizing valve and an air source, pumping the liquid in the sewage tank into the coalescer by a feed pump, and controlling the inflow of water to be 0.1-0.5m by regulating the flow regulating valve³Within/h; the oil phase in the sewage is slowly attached to the surface of the fiber and then is gathered to form oil drops, the large-particle oil drops are carried away from the surface of the fiber by the water phase and enter the oil collecting tank through the oil phase outlet, and the water phase without the oil phase enters the water producing tank through the water phase outlet.

The invention has the advantages and beneficial technical effects as follows:

(1) the porous fiber material for oil-water separation is prepared by a thermally induced phase separation method, and the preparation process is simple and easy to operate;

(2) the main raw material polypropylene has rich sources, easily-controlled specification indexes and low price, has excellent chemical reagent resistance and higher mechanical strength, ensures that the quality of the prepared coalescent fiber is reliable, improves the mechanical property of the material by blending and adding high-density polyethylene, improves the lipophilic and hydrophilic balance, is beneficial to the flowing and falling of a surface oil film, and improves the coalescent and separation efficiency of oil drops in water;

(3) the coagulation bath and the diluent are dissolved and exchanged during the molding of the nascent fiber, so that the generation of a compact skin layer is avoided, a large number of micropores can be generated on the surface of the fiber, and the nascent fiber is slowly cooled by the coagulation bath at different temperatures, so that the internal stress of the fiber can be reduced to the maximum extent, the mechanical and thermal properties of a fiber coalescence material are improved, and the phenomena of stress cracking, warping deformation and the like are prevented;

(4) the addition of the nucleating agent improves the thermal stability, the impact strength and other properties of the prepared fiber, the pore size distribution is uniform, the pore-forming diluent and other additives are environment-friendly, non-toxic or low-toxic, the extracting agent is an industrial conventional reagent, and the second and third-stage coagulation baths are simple, convenient and easily-obtained non-solvent deionized water, so that the production cost in the whole process is greatly reduced;

(5) the oil-water separation equipment filled with the porous fiber has the advantages of compact structure, full sealing, safety and explosion prevention, realizes the device treatment of oil sewage, has high treatment efficiency, can recycle the recovered dirty oil as resources, does not generate any waste residue, and does not cause secondary pollution.

Drawings

FIG. 1 is a schematic structural diagram of an apparatus for oil-water separation according to the present invention;

description of reference numerals: 1: a gas source; 2: a liquid storage tank; 3: a pressure maintaining valve; 4: a sewage pump; 5: a sewage tank; 6: a flow regulating valve; 7: a flow meter; 8: a feed pump; 9: a coalescer; 10: a water producing tank; 11: an oil collecting tank.

Detailed Description

The present invention is described below with reference to specific examples, which are not intended to limit the scope of the present invention, and those skilled in the art may make insubstantial modifications and adaptations of the present invention based on the above-described disclosure.

The starting materials used in the examples are all commercially available unless otherwise specified.

The test method comprises the following steps:

the specific surface area of the prepared fiber material is measured according to national standard GB/T19587-.

The oil content in the water is measured according to the national standard GB/T16488 and 1996 determination of water quality petroleum and animal and vegetable oil;

the oil removal rate was calculated as follows:

in the formula, C₀Represents the oil content of the oily sewage in the sewage tank, mg/L;

c represents the oil content of the water phase in the water production tank, mg/L.

As shown in fig. 1, the apparatus for oil-water separation of the present invention comprises an air source 1, a liquid storage tank 2, a pressure-stabilizing valve 3, a sewage pump 4, a sewage tank 5, a flow-regulating valve 6, a flow meter 7, a feed pump 8, a coalescer 9, a water production tank 10, and a oil collection tank 11.

Wherein, the liquid storage tank 2 is used for storing oily sewage, the temperature of the sewage is 30-50 ℃, and the sewage is sequentially connected with a sewage pump 4 through a pipeline; the sewage pump 4 is connected with a sewage inlet of the sewage tank 5 through a pipeline and is used for pumping the oily sewage in the liquid storage tank 2 into the sewage tank 5. The gas source 1 is connected with a gas inlet of a sewage tank 5 through a pipeline, a pressure stabilizing valve 3 is arranged on the pipeline, and in the embodiment of the invention, the gas source 1 is preferably a nitrogen cylinder. The sewage outlet of the sewage tank 5 is connected with a feed pump 8 through a pipeline, a flow regulating valve 6 and a flow meter 7 are sequentially arranged on the pipeline, and the feed pump is connected with the inlet of a coalescer 9 through a pipeline and is used for pumping the sewage in the sewage tank 5 into the coalescer 9 for treatment. The coalescer 9 is filled with porous fibers to treat the wastewater and separate the oil phase from the water phase. The coalescer comprises an oil phase outlet and a water phase outlet, the oil phase outlet is connected with the oil collecting tank 11 through a pipeline, and the water phase outlet is connected with the water producing tank 10 through a pipeline.

Examples 1 to 24 and comparative examples 1 to 7

(1) Adding polypropylene resin into a spinning kettle with a stirring device, mixing the polypropylene resin with high-density polyethylene, a diluent and a nucleating agent in proportion, heating to a certain temperature for melting, stirring for a period of time under the condition of introducing nitrogen, stopping stirring, standing for a period of time for defoaming, and obtaining a spinning solution.

(2) And after filtering the spinning solution by a filter screen, conveying the spinning solution to a spinning nozzle by a metering pump, extruding the spinning solution melt at a constant speed to form nascent fiber, cooling by a three-stage coagulating bath to obtain fiber filament, and winding and collecting by a traction wheel.

(3) And (3) extracting the prepared nascent fiber in an extracting agent for a period of time, naturally drying in a fume hood, and removing water adsorbed on the surface to obtain the porous fiber.

The data of each step are shown in Table 1.

TABLE 1

Examples 25 to 52 and comparative examples 8 to 16

The device shown in figure 1 is adopted to treat oily wastewater of a certain refinery, the pH of the wastewater is 7.5, and the oil content is 1186 mg/L.

(1) The porous fibers prepared in examples 1 to 24 and comparative examples 1 to 7 were packed in layers in a coalescer bed at a packing ratio of 1/2;

(2) pumping the oily sewage with the temperature of 30-50 ℃ in the liquid storage tank into a sewage tank through a sewage pump;

(3) opening the flow regulating valve, the flowmeter, the pressure stabilizing valve and the air source, pumping the liquid in the sewage tank into the coalescer by the feeding pump, and regulating the flowThe quantity regulating valve controls the water inlet flow to be 0.1-0.5m³/h。

And measuring data after the operation is stable, and calculating to obtain the oil removal rate.

The data for each example and comparative example are shown in table 2.

TABLE 2

Any numerical value mentioned in this specification, if there is only a two unit interval between any lowest value and any highest value, includes all values from the lowest value to the highest value incremented by one unit at a time. For example, if it is stated that the amount of a component, or a value of a process variable such as temperature, pressure, time, etc., is 50 to 90, it is meant in this specification that values of 51 to 89, 52 to 88. For non-integer values, units of 0.1, 0.01, 0.001, or 0.0001 may be considered as appropriate. These are only some specifically named examples. In a similar manner, all possible combinations of numerical values between the lowest value and the highest value enumerated are to be considered to be disclosed in this application.

It should be noted that the above-mentioned embodiments are only for explaining the present invention, and do not constitute any limitation to the present invention. The present invention has been described with reference to exemplary embodiments, but the words which have been used herein are words of description and illustration, rather than words of limitation. The invention can be modified, as prescribed, within the scope of the claims and without departing from the scope and spirit of the invention. Although the invention has been described herein with reference to particular means, materials and embodiments, the invention is not intended to be limited to the particulars disclosed herein, but rather extends to all other methods and applications having the same functionality.