A low-carbon olefin hydration product separation fiber membrane and a preparation method and application thereof

Abstract

The present application relates to the technical field of low carbon olefin hydration product separation, and discloses a low carbon olefin hydration product separation fiber membrane and a preparation method and application thereof.A low carbon olefin hydration product separation fiber membrane, wherein the low carbon olefin hydration product separation fiber membrane comprises a hollow fiber membrane base, a first silane layer, a first dehydration layer and a first separation layer are coated on the inner surface of the hollow fiber membrane base from inside to outside, and a second silane layer and a second dehydration layer are coated on the outer surface of the hollow fiber membrane base from inside to outside; the first dehydration layer and the second dehydration layer each independently contain an amide group, a pyrrole group and a furan group; and the first separation layer contains a pyrrole group and a furan group.The low carbon olefin hydration product separation fiber membrane can improve the retention rate of low carbon alcohol in the olefin hydration product, effectively recover the water in the product and improve the yield of the olefin hydration low carbon alcohol.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of low-carbon olefin hydration product separation, and particularly relates to a low-carbon olefin hydration product separation fiber membrane and a preparation method and application thereof. BACKGROUND

[0002] Olefin hydration is one of important organic reactions, and can be used for preparing alcohols, such as cyclohexanol, which is an intermediate raw material for producing adipic acid, caprolactam and important chemical products such as medicines, paints and dyes; is commonly used as a solvent for paints, shellac and varnish in the paint industry; can be used as a stabilizer and uniformizer for emulsion in the synthesis of detergents; can be used as a dye solvent and scouring and boiling aid in the textile industry; in addition, can be used for preparing flavorings, rubber anti-aging agents, fruit mildew-proof agents and the like.

[0003] Traditional olefin hydration generally adopts sulfuric acid indirect hydration method, which has problems such as serious equipment corrosion and waste acid treatment, and has been gradually replaced by catalytic direct hydration method. In the catalytic direct hydration method, low-carbon olefins can be directly converted into corresponding low-carbon alcohols under the catalysis of a solid acid catalyst. The crude low-carbon alcohol mixture generated in the reaction is then removed from the reaction system, and the olefins, water and olefin oligomers are removed step by step in a separation system to obtain low-carbon alcohol products, and the olefins and water obtained by rectification can be returned to the hydration system for continuous use.

[0004] From the current research, it can be seen that the olefin hydration products are removed from the reaction system in time, which is very beneficial to promoting the hydrolysis equilibrium to move to the right. However, the conversion rate per pass is low and the alcohol content in the aqueous solution is not high when the conventional solid acid catalyst is used for catalyzing olefin hydration. The current conventional separation process is dehydration in a rectification tower, one end of which obtains recycled water and the other end of which obtains alcohol concentrate. Due to the large water-olefin ratio in the olefin hydration process and the low alcohol concentration in the hydration products, the energy consumption of the device is very high. Membrane separation is a new type of separation technology, and is currently mainly used for water treatment. The commercial membranes on the market are mainly developed for water separation. For specific materials or materials with great difference from water, the separation effect is very poor.

[0005] Patent application CN103764268A discloses a reactor for catalytic hydration of olefins, the reactor comprises: a catalytic reaction zone, which is separated by a permeable membrane to form a permeate side and a retentate side, the retentate side contains an olefin hydration catalyst; a first outlet for removing fluid from the permeate side; a second outlet for removing fluid from the retentate side; the permeable membrane is operable to selectively remove at least one olefin hydration product; the permeable membrane is selected from polymeric or inorganic membranes, such as POL-Al_M1, hydrophobic PERVAP4060, WTA303 or 51-15130, the membrane can selectively pass certain alcohols, such as alcohols having less than 6 carbon atoms, but does not allow non-organic compounds, such as water, or specific gases, such as hydrogen or nitrogen, to pass through, and specific non-alcohol compounds, such as aromatic compounds or olefins, are generally not easily permeable; the catalyst is a solid acid catalyst. Although the membrane has good selective permeation effect on alcohols, the content of alcohols in the product mixture is low due to the inhibition of alcohols on the hydration equilibrium in the conventional olefin hydration product, and the material circulation amount and membrane area required for selectively permeating alcohols from a dilute alcohol solution are large, and the economy is not as good as using an adsorption resin to separate and desorb low-concentration alcohols.

[0006] Patent application CN104039435A discloses an integrated membrane hydration reactor, which comprises: a solid acid olefin hydration catalyst capable of effectively converting the olefins into the relevant alcohol using water under olefin hydration process conditions; a hydrophilic membrane having a feed side and a permeate side, which is used to selectively permeate and vaporize water from the feed side to the permeate side under olefin hydration process conditions, thereby forming a permeate vaporization water product, and is capable of preventing the permeation and vaporization of the relevant alcohol and the olefin under the olefin hydration conditions. The membrane can be made of inorganic materials, organic materials, or organic-inorganic composite materials. The inorganic materials include ceramics, metals, mixed metal oxides, glasses, etc. The organic materials include polyolefins, polyisoprene, polybutadiene, fluorinated polymers, chlorinated polymers, polyesters, polyamides, polyimides, polyethers, sulfonated and non-sulfonated poly(ether sulfone), poly(sulfone), polyphenylene ether, polyphenylene sulfide, etc. When the permeate vaporization membrane is used, the hydration product (water-alcohol emulsion) needs to be first allowed to stand and separate (to form an alcohol-rich layer and a water-rich layer), and then dehydrated, and then the hydrophilic permeate vaporization membrane is contacted with the water-rich layer to perform dehydration. This process converts the water-alcohol emulsion into a conventional water-rich material for dehydration, reduces the separation difficulty of the research problem, and facilitates the direct use of commercial water-based permeate vaporization membranes. However, the membrane has a high difficulty in directly dehydrating the water-alcohol emulsion, and the alcohols in the emulsion will hinder the contact between water and the permeate vaporization membrane, thereby reducing the permeation treatment capacity. SUMMARY

[0007] The application aims to overcome the problems of high energy consumption in the rectification of low-carbon olefin hydration product separation and low rejection rate of low-carbon alcohol by conventional membranes in the prior art, and provides a low-carbon olefin hydration product separation fiber membrane, a preparation method and application thereof, which can improve the rejection rate of low-carbon alcohol in olefin hydration product, effectively recover water in the product, and improve the yield of olefin hydration low-carbon alcohol.

[0008] To achieve the above-mentioned purpose, the application provides a low-carbon olefin hydration product separation fiber membrane, wherein the low-carbon olefin hydration product separation fiber membrane comprises a hollow fiber membrane base, a first silane layer, a first dehydration layer and a first separation layer are coated on the inner surface of the hollow fiber membrane base from inside to outside, and a second silane layer and a second dehydration layer are coated on the outer surface of the hollow fiber membrane base from inside to outside; the first dehydration layer and the second dehydration layer each independently contain an amide group, a pyrrole group and a furan group; and the first separation layer contains a pyrrole group and a furan group.

[0009] The application provides a preparation method of the low-carbon olefin hydration product separation fiber membrane, and the method comprises the following steps:

[0010] (1) performing silanization treatment on the hollow fiber membrane base to obtain a silanized hollow fiber membrane;

[0011] (2) performing dehydration treatment on the silanized hollow fiber membrane in step (1) by using a solution containing a dehydration component to obtain a hollow fiber membrane after dehydration treatment;

[0012] (3) performing first separation treatment on the inner surface of the hollow fiber membrane after dehydration treatment in step (2) by using a solution containing a first separation component to obtain a low-carbon olefin hydration product separation fiber membrane;

[0013] The dehydration component contains an amide group, a pyrrole group and a furan group, and the first separation component contains a pyrrole group and a furan group.

[0014] The application provides an application of the low-carbon olefin hydration product separation fiber membrane in the first aspect or the low-carbon olefin hydration product separation fiber membrane prepared by the preparation method in the second aspect in low-carbon olefin hydration product separation.

[0015] During their research on the hydration of low-carbon olefins, the inventors of this invention discovered that using existing solid acid catalysts such as strong acid resins and ZSM-5 molecular sieves to catalyze olefin hydration resulted in a significantly lower single-pass conversion rate compared to the thermodynamic equilibrium conversion rate. To improve the yield of low-carbon alcohols, a large excess of water to olefins was typically used. The aim was to shift the hydration equilibrium to the right by using excess reactants, thereby diluting the low-carbon alcohol product and reducing the inhibitory effect on the hydration reaction. These factors combined resulted in significant difficulties in recovering and utilizing excess water from the olefin hydration product and extremely high energy consumption in the distillation process for concentrating low-carbon alcohols. The inventors attempted to directly use existing commercial membranes (water treatment separation membranes) for the separation of low-concentration low-carbon alcohol aqueous solutions, but the separation effect was poor, with a low-carbon alcohol retention rate of only 0-8%. Furthermore, the olefins contained in the material led to low stability and easy damage of conventional commercial membranes.

[0016] The low-carbon olefin hydration product separation fiber membrane provided by this invention uses a hollow fiber membrane as a substrate. A first silane layer, a first dehydration layer, and a first separation layer are sequentially coated from the inside to the outside of the inner surface of the hollow fiber substrate. A second silane layer and a second dehydration layer are sequentially coated from the inside to the outside of the outer surface of the hollow fiber substrate. The first and second silane layers mainly function as dielectric layers, connecting the substrate and the secondary modification layer, improving the stability of subsequent modification layers and extending their service life.

[0017] The low-carbon olefin hydration product separation fiber membrane provided by the present invention is applicable to the separation of low-concentration and high-concentration low-carbon alcohols (preferably, the content of low-carbon alcohols is 0.5-90% by mass), thus expanding the scope of application of low-carbon alcohol separation.

[0018] The low-carbon olefin hydration product separation fiber membrane provided by the present invention can improve the retention rate of low-carbon alcohols. For example, in the embodiments, the retention rate of low-carbon alcohols can reach more than 85%, which is much higher than the 0-8% retention rate in the prior art. At the same time, it reduces energy consumption. Detailed Implementation

[0019] The endpoints and any values ​​of the ranges disclosed herein are not limited to the precise 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 the various ranges, the endpoint values ​​of the various ranges and individual point values, and individual point values ​​can be combined with each other to obtain one or more new numerical ranges, which should be considered as specifically disclosed herein.

[0020] In this invention, it is understood that the groups and their contents in the membrane layers mentioned herein were all determined by infrared spectroscopy, specifically under KBr pellet compression at 400 cm⁻¹. -1 -4000cm -1The content of the groups in each layer was determined by stepwise measurement during the preparation process.

[0021] In the present application, it can be understood that the thickness of the film layer referred to herein is measured by an X-ray fluorescence thickness gauge.

[0022] The low-carbon olefin hydration product separation fiber membrane provided by the first aspect of the present application comprises a hollow fiber membrane substrate, a first silane layer, a first dehydration layer and a first separation layer coated on the inner surface of the hollow fiber membrane substrate from inside to outside, and a second silane layer and a second dehydration layer coated on the outer surface of the hollow fiber membrane substrate from inside to outside; the first dehydration layer and the second dehydration layer each independently contain an amide group, a pyrrole group and a furan group; and the first separation layer contains a pyrrole group and a furan group.

[0023] In the present application, the first separation layer is grafted with a low-carbon alcohol strong repulsion group to form a low-carbon alcohol barrier layer to inhibit the permeation and mass transfer of low-carbon alcohol, while the preferred group has no inhibition on the permeation of water molecules and allows free mass transfer of water molecules. The first dehydration layer and the second dehydration layer are each grafted with a hydrophilic group and a low-carbon alcohol repulsion group. Water is enriched on the outer surface, the pores and the inner surface of the substrate through the hydrophilic group. After the water enriched in the lumen of the hollow fiber membrane is extracted, the water molecules in the liquid phase body are continuously enriched through the outer surface of the membrane, the pores and the inner surface to the lumen of the fiber membrane, forming a continuous mass transfer flow. For high-concentration low-carbon alcohol after low-concentration low-carbon alcohol is concentrated by membrane separation, due to the influence of physical properties such as surface tension and osmotic pressure, membrane separation generally cannot be applied to high-concentration low-carbon alcohol material conditions, but the hydration separation membrane provided by the present application realizes micro-water enrichment by grafting a hydrophilic group, so that macro high-concentration low-carbon alcohol is converted into micro low-concentration low-carbon alcohol, so that the separation membrane is suitable for both low-concentration and high-concentration low-carbon alcohol conditions. In the water mass transfer process, the low-carbon alcohol repulsion group grafted on the first dehydration layer and the second dehydration layer can prevent low-carbon alcohol from entering the outer surface of the membrane or the inner wall of the membrane, and cooperates with the first separation layer to promote the mass transfer of a small amount of low-carbon alcohol entering the membrane wall from the inner surface to the outer surface along the pores, and then to the liquid phase body. Through targeted modification of the substrate membrane, high retention of low-carbon alcohol and high permeation of water in low-carbon alcohol aqueous solution can be realized.

[0024] In the present application, the hollow fiber membrane substrate is a hollow cylinder with a hollow structure inside, which is commonly defined in the art. The inner surface referred to herein is the inner surface of the hollow cylinder, and the outer surface referred to herein is the outer surface of the hollow cylinder.

[0025] In the present application, the type of hollow fiber membrane substrate is not particularly limited and can be a commonly used hollow fiber membrane in the art. Preferably, the hollow fiber membrane substrate is a hollow ceramic fiber.

[0026] In the present application, preferably, the hollow fiber membrane base has an inner diameter of 1.8-2.8 mm, an outer diameter of 2.9-4.8 mm, a fiber membrane wall pore size of 25-75 nm, and a porosity of 45-65%.

[0027] In the present application, the material of the hollow fiber membrane base is not particularly limited. Preferably, the material of the hollow fiber membrane base is silicon dioxide and / or aluminum oxide.

[0028] In the present application, preferably, the first silane layer and the second silane layer each independently have a thickness of 6-10 nm.

[0029] In the present application, it can be understood that the first silane layer and the second silane layer are prepared by immersing the hollow fiber membrane in a solution containing a silane component, and the inner surface and the outer surface of the hollow fiber membrane are both in contact with the silane component, and the first silane layer and the second silane layer have the same thickness.

[0030] In the present application, preferably, the first silane layer and the second silane layer each independently are provided by at least one of 2-butenyltriethoxysilane, methylvinyl diethoxysilane, and allyldimethoxysilane.

[0031] In the present application, preferably, in the first dehydration layer, the content of amido group is 20-39 mmol / m 2 , the content of pyrrolyl group is 15-25 mmol / m 2 , and the content of furanyl group is 2.5-6 mmol / m 2 .

[0032] In the present application, preferably, in the second dehydration layer, the content of amido group is 20-39 mmol / m 2 , the content of pyrrolyl group is 15-25 mmol / m 2 , and the content of furanyl group is 2.5-6 mmol / m 2 .

[0033] In the present application, preferably, the first dehydration layer and the second dehydration layer each have a thickness of 8-13 nm.

[0034] In the present application, it can be understood that the first dehydration layer and the second dehydration layer are prepared by immersing the hollow fiber membrane in a solution containing a dehydration component, and the inner surface and the outer surface of the hollow fiber membrane are both in contact with the dehydration component, and the first dehydration layer and the second dehydration layer have the same thickness.

[0035] In the present application, preferably, the content of the pyrrole group in the first separation layer is 18-30 mmol / m 2 , and the content of the furan group is 3-8 mmol / m 2 .

[0036] In the present application, preferably, the thickness of the first separation layer is 10-16 nm. The advantage of using this preferred embodiment is that it can simultaneously take into account the high retention of low carbon alcohol and the high permeability of water.

[0037] The second aspect of the present application provides a preparation method of a low carbon olefin hydration product separation fiber membrane, wherein the method comprises:

[0038] (1) performing silanization treatment on a hollow fiber membrane substrate to obtain a silanized hollow fiber membrane;

[0039] (2) performing dehydration treatment on the silanized hollow fiber membrane in step (1) using a solution containing a dehydration component to obtain a hollow fiber membrane after dehydration treatment;

[0040] (3) performing first separation treatment on the inner surface of the hollow fiber membrane after dehydration treatment in step (2) using a solution containing a first separation component to obtain a low carbon olefin hydration product separation fiber membrane;

[0041] The dehydration component contains an amide group, a pyrrole group and a furan group, and the first separation component contains a pyrrole group and a furan group.

[0042] In the present application, the type, material and characteristic parameters of the hollow fiber membrane substrate in step (1) have been described in the first aspect and will not be repeated here.

[0043] In the present application, the preparation method of the hollow fiber membrane substrate is not particularly limited, and can be a method conventionally defined in the art, for example, can be prepared by the following method: first, a casting solution is prepared, then a hollow fiber embryo is prepared by a process of spinning forming-phase inversion, and then dried and calcined to obtain a hollow ceramic fiber, and the preparation conditions of the hollow ceramic fiber are as follows: polyether sulfone (average molecular weight 1500-3800), N-methyl pyrrolidone, ceramic precursor (silicon dioxide or aluminum oxide), polyvinyl pyrrolidone K90, in a mass ratio of (9-18):(65-95):(170-330):(4-9), stirring at 75-95°C for 40-60 hours, and then standing for 7-12 hours to remove bubbles to obtain the casting solution. The inner and outer gel baths of the spinneret are deionized water at 0-3°C, the inner diameter of the spinneret is 2-3 mm, the outer diameter is 3-5 mm, the casting solution flow rate is 2-6 ml / min, the casting solution pressure in the spinneret is 120-240 kPa (gauge pressure), the ambient temperature is 20-30°C, the ambient humidity is 45-60%, and the casting solution exchanges solvents with the inner and outer gel baths and phase separates to form a hollow fiber blank. The hollow fiber membrane embryo is washed with desalted water for 4-8 times, dried with air at 20-30°C, then heated at a rate of 0.5-1°C / min to 1600-1800°C, kept at a constant temperature for 4-8 hours, then naturally cooled to 20-30°C, to obtain a hollow ceramic fiber membrane substrate.

[0044] In the present application, preferably, in step (1), the silanization treatment allows the inner surface and the outer surface of the hollow fiber membrane substrate to be respectively coated with a first silane layer and a second silane layer, and the thickness of the first silane layer and the second silane layer is independently 6-10 nm.

[0045] In the present application, preferably, the silanization treatment comprises: contacting a silane reagent solution with the hollow fiber membrane substrate, and then drying and curing. In the present application, the conditions for contacting are not particularly limited. Preferably, the contacting is soaking, and the soaking time is 100-200 seconds. In the present application, the conditions for drying and curing are not particularly limited. Preferably, the temperature is 100-120°C, and the time is 30-60 minutes. In the present application, preferably, the drying and curing is carried out in a protective atmosphere, preferably an inert atmosphere or nitrogen.

[0046] In the present application, preferably, in step (1), the silane reagent solution is obtained by pre-hydrolysis of a silane reagent, water and anhydrous low-carbon alcohol. In the present application, the conditions for pre-hydrolysis are not particularly limited. Preferably, the pre-hydrolysis time is 12-24 hours.

[0047] In the present application, the content of each component in the silane reagent solution is not particularly limited, as long as the thickness requirements of the first silane layer and the second silane layer are met. Preferably, the volume ratio of the silane reagent: water: low-carbon alcohol is (2.4-5.4):(4-6):(88-94).

[0048] In the present application, preferably, the pH value of the silane reagent solution is 7.4-8.3.

[0049] In the present application, the type of silane reagent is not particularly limited. Preferably, the silane reagent is selected from at least one of 2-butenyl triethoxysilane, methyl vinyl diethoxysilane, and allyl dimethoxysilane.

[0050] In the present application, the specific type of low-carbon alcohol is not particularly limited. Preferably, the low-carbon alcohol is anhydrous methanol and / or anhydrous ethanol.

[0051] In the present application, the amount of the silane reagent solution is not particularly limited. Preferably, in step (1), the amount of the silane reagent solution is such that the thickness of the first silane layer and the second silane layer is independently 6-10 nm.

[0052] In the present application, preferably, in step (2), the dehydration treatment is such that the silanization is such that the inner surface and the outer surface of the hollow fiber membrane substrate are respectively coated with a first dehydration layer and a second dehydration layer, and the first dehydration layer and the second dehydration layer each independently contain an amide group, a pyrrole group, and a furan group.

[0053] In the present application, the content of each group in the first dehydration layer and the second dehydration layer has been described in the first aspect, and will not be repeated here.

[0054] In the present application, the operation mode of the dehydration treatment is not particularly limited. Preferably, in step (2), the dehydration treatment comprises: contacting a solution containing a dehydration treatment component with the silanized hollow fiber membrane of step (1).

[0055] In the present application, preferably, in step (2), the solution containing the dehydration treatment component contains a dehydration component, a first initiator, and a first solvent.

[0056] In the present application, preferably, in step (2), the dehydration treatment component is provided by an amide derivative, a pyrrole derivative, and a furan derivative.

[0057] In the present application, preferably, in step (2), the molar ratio of the amide derivative: pyrrole derivative: furan derivative is (23-45):(17-29):(3-7).

[0058] In the present application, preferably, the amido group is provided by an amido derivative, preferably the amido derivative is at least one selected from the group consisting of N,N'-dihydroxyethyl bisacrylamide, N,N-methylene bisacrylamide and hexamethylene bisacrylamide.

[0059] In the present application, preferably, the pyrrolyl group is provided by a pyrrole derivative, preferably the pyrrole derivative is at least one selected from the group consisting of 3-isopropenyl-1-methyl-pyrrole, 1-(3-buten-1-yl)-2-vinyl-1H-pyrrole and 5-allyl-4-methoxy-1,5-dihydro-2H-pyrrol-2-one.

[0060] In the present application, preferably, the furanyl group is provided by a furan derivative, preferably the furan derivative is 2-(1-propen-2-yl)furan and / or 2-(2-pentenyl)furan.

[0061] In the present application, preferably, in step (2), the first solvent is at least one selected from the group consisting of toluene, p-xylene, m-xylene and o-xylene.

[0062] In the present application, preferably, in step (2), the first initiator is at least one selected from the group consisting of azo, organic peroxide, inorganic peroxide and redox initiators, preferably at least one selected from the group consisting of azobisisobutyronitrile, benzoyl peroxide, potassium persulfate and hydrogen peroxide.

[0063] In the present application, preferably, in step (2), the mass ratio of the dehydrating component, the first initiator and the first solvent in the solution containing the dehydrating component is (5-9):(0.1-0.5):(90-96).

[0064] In the present application, preferably, in step (2), the conditions of the dehydration treatment include that the liquid-solid volume ratio of the solution containing the dehydrating component to the hollow fiber membrane silanized in step (1) is 3-6, the soaking temperature is 63-85℃, and the time is 1.5-3h.

[0065] In the present application, preferably, step (2) further comprises subjecting the dehydration treatment product to a first post-treatment agent for dehydration post-treatment.

[0066] In the present application, the type of the first post-treatment agent is not particularly limited. Preferably, the first post-treatment agent is at least one selected from the group consisting of anhydrous ethanol, anhydrous methanol and anhydrous acetone, and is further preferably anhydrous ethanol.

[0067] In the present application, the conditions of the first post-treatment are not particularly limited. Preferably, the conditions of the dehydration post-treatment include that the soaking time is 0.5-1h, the drying temperature is 110-130℃, and the drying time is 0.5-1h.

[0068] In the present application, preferably, in step (3), the first separation treatment is such that the inner surface of the hollow fiber membrane after the dehydration treatment in step (2) is coated with a first separation layer, and the first separation layer contains a pyrrole group and a furan group.

[0069] In the present application, the content of each group in the first separation layer has been described in the first aspect, and will not be repeated here.

[0070] In the present application, preferably, in step (3), the solution containing the first separation component contains a polyether, the first separation component, a second initiator and water.

[0071] In the present application, preferably, in the solution containing the first separation component, the mass ratio of polyether: first separation component: second initiator: water is 100: (7-13): (0.5-0.9): (1.2-2.7).

[0072] In the present application, preferably, the average molecular weight of the polyether is 700-1800.

[0073] In the present application, in step (3), the first separation component is provided by a pyrrole derivative and a furan derivative.

[0074] In the present application, the specific types of pyrrole derivatives and furan derivatives have been described in the foregoing, and will not be repeated here.

[0075] In the present application, preferably, the molar ratio of pyrrole derivative: furan derivative is (21-36): (3.5-9).

[0076] In the present application, the specific type of the second initiator is not particularly limited, and can be the same as or different from the first initiator.

[0077] In the present application, the first separation treatment completely fills the inner cavity of the hollow fiber membrane, so that the first polyether (the polyether exists in the form of a gel) is only coated on the inner surface of the hollow fiber membrane and the part of the pore channel close to the inner surface, and the outer surface is not coated. Preferably, in step (3), the first separation treatment comprises: introducing the solution containing the first separation component into the inner cavity of the hollow fiber membrane after the dehydration treatment in step (2), and the back pressure of the inner cavity outlet is 8-15 kg in terms of gauge pressure. Preferably, the first functional treatment further comprises: after introducing the solution containing the first separation component, then treating at 80-100°C for 0.8-1.5 hours in a protective atmosphere (preferably nitrogen), cooling to room temperature, and then soaking and washing 4-8 times with an organic solvent (preferably acetonitrile) at 50-70°C, and then drying in a nitrogen atmosphere. The advantage of this preferred embodiment is that a low-carbon alcohol barrier layer is further grafted on the inner surface of the separation membrane, which can improve the rejection rate of the membrane to low-carbon alcohols.

[0078] In the present application, preferably, the step (3) further comprises subjecting the first separation treatment product to a second separation treatment in a second post-treatment agent. In the present application, the specific type of the second post-treatment agent is not particularly limited, and can be the same as or different from the first post-treatment agent.

[0079] In the present application, preferably, the conditions of the separation treatment comprise: the soaking time is 0.5-1h, the drying temperature is 120-150℃, and the drying time is 0.5-1h.

[0080] The third aspect of the present application provides an application of the low-carbon olefin hydrate separation fiber membrane of the first aspect or the low-carbon olefin hydrate separation fiber membrane prepared by the preparation method of the second aspect in low-carbon olefin hydrate separation.

[0081] In the present application, preferably, the low-carbon olefin hydrate separation comprises: in the presence of the low-carbon olefin hydrate separation fiber membrane, the low-carbon olefin hydrate is contacted with the outer surface of the low-carbon olefin hydrate separation fiber membrane, and the inner cavity of the low-carbon olefin hydrate separation fiber membrane obtains pure water, and the outside of the low-carbon olefin hydrate separation fiber membrane obtains a low-carbon alcohol-containing aqueous solution.

[0082] In the present application, preferably, the low-carbon olefin hydrate is a low-carbon alcohol-containing low-carbon olefin hydrate synthesized by a carbon three and / or carbon four low-carbon olefin hydrate synthesis reaction.

[0083] In the present application, preferably, in the low-carbon alcohol-containing low-carbon olefin hydrate, the content of the low-carbon alcohol is 0.5-90% by mass based on the total amount of the low-carbon alcohol-containing low-carbon olefin hydrate.

[0084] In the present application, preferably, the conditions of the contacting comprise: the temperature is 20-40℃, and the pressure is 0.5-4MPa in terms of gauge pressure.

[0085] In the present application, the equipment used for the olefin hydration reaction is not particularly limited. Preferably, the low-carbon olefin hydrate separation is carried out in an olefin hydration separator, and preferably, a shell-and-tube structure olefin hydration separator is used. In one specific embodiment, the low-carbon olefin hydrate separation fiber membranes are arranged in parallel in the olefin hydration separator, the low-carbon olefin hydrate (preferably, a low-carbon alcohol-containing low-carbon olefin hydrate) flows through the shell side of the olefin hydration separator (i.e., the low-carbon alcohol-containing low-carbon olefin hydrate is contacted with the outer surface of the hollow fiber membrane), and after the contact separation, the water (the recovered purified water) flows through the tube side of the olefin hydration separator (i.e., the water is contacted with the inner surface of the hollow fiber membrane).

[0086] In the present application, preferably, the rejection rate of the low-carbon alcohol is greater than 85%.

[0087] The present application will be described in detail below through examples.

[0088] In the present application, the content of each group in the olefin hydration fiber membrane is measured by the test method described above.

[0089] In the present application, component analysis is performed using a 20A high-performance liquid chromatography system (Shimadzu Corporation, Japan, with an automatic sampler, 10AT and 10AD pumps, and a 20A multi-wavelength ultraviolet detector); an ACQUITY UPLC / Xevo G2 QTOF ultra-high-performance liquid chromatography high-resolution tandem mass spectrometer (Waters Corporation, USA, with an automatic sampler and a diode array ultraviolet detector). The high-performance liquid chromatography conditions are as follows: a Zorbax Eclipse Plus C18 column (4.6 mm x 150 mm, 5 μm), a mobile phase of water (containing 0.06% v of phosphoric acid): acetonitrile = 95:5, a flow rate of 1.0 mL / min, a detection wavelength of 210 nm, a column temperature of 35°C, and a sample injection amount of 1 μL. The ultra-high-performance liquid chromatography conditions are as follows: a HSS T3 column (2.1 mm x 100 mm, 1.7 μm), a mobile phase of water and methanol, gradient elution (positive ion mode): 0 min V (water): V (methanol) = 85:15, 2.5 min V (water): V (methanol) = 55:35, 4 min V (water): V (methanol) = 10:90, a flow rate of 0.45 mL / min, gradient elution (negative ion mode): 0 min V (water): V (methanol) = 70:30, 2.5 min V (water): V (methanol) = 55:35, 3.5 min V (water): V (methanol) = 10:90, a flow rate of 0.45 mL / min, a column temperature of 30°C, and a sample injection amount of 3 μL. The mass spectrometry conditions are as follows: an electrospray ionization source (ESI), positive or negative ion scanning mode, a capillary voltage of 2 kV, a cone hole voltage of 30 eV, an ion source temperature of 120°C, a desolvation temperature of 450°C, a cone hole gas flow rate of 50 L / h, and a desolvation gas (N2) flow rate of 900 L / h.

[0090] In the following examples, the preparation method of the low-carbon olefin water separation fiber membrane comprises the following steps: (1) silanizing the inner and outer surfaces of the hollow fiber membrane substrate to obtain a silanized hollow fiber membrane; (2) dehydrating the inner and outer surfaces of the silanized hollow fiber membrane obtained in step (1) to obtain a dehydrated hollow fiber membrane; and (3) performing a first separation treatment on the dehydrated hollow fiber membrane obtained in step (2) to obtain a low-carbon olefin hydration separation fiber membrane.

[0091] Example 1

[0092] In this example, the composition of the low-carbon olefin hydration reaction product comprises, by mass percentage, 13.2% of sec-butanol, 0.3% of di-sec-butyl ether, and 86.5% of water.

[0093] The hollow fiber membrane substrate is prepared by first preparing a casting solution, then preparing a hollow fiber precursor by a process of spinning-forming phase inversion, and then drying and calcining to obtain a hollow ceramic fiber, the preparation conditions of the hollow ceramic fiber being as follows: polyether sulfone (average molecular weight 2650), N-methyl pyrrolidone, ceramic precursor (silicon dioxide), polyvinyl pyrrolidone K90, in a mass ratio of 13.4:81:251:6.4, stirring at 84°C for 50 hours, and then standing for 9.4 hours to remove bubbles to obtain a casting solution. The inner and outer gel baths of the spinneret are deionized water at 1.5°C, the inner diameter of the spinneret is 2.5 mm, the outer diameter is 3.5 mm, the casting solution flow rate is 4 ml / min, the inner casting solution pressure of the spinneret is 180 kPa (gauge pressure), the ambient temperature is 25°C, the ambient humidity is 53%, the casting solution exchanges solvents with the inner and outer gel baths and phase separates to form a hollow fiber precursor. The hollow fiber membrane precursor is washed with desalted water for 6 times, then dried with air at 25°C, then heated at a rate of 0.8°C / min to 1720°C, kept at this temperature for 6 hours, then naturally cooled to 25°C to obtain a hollow ceramic fiber membrane substrate. The obtained hollow ceramic fiber has an inner diameter of 2.3 mm, an outer diameter of 3.3 mm, a fiber membrane wall pore size of 51 nm, and a porosity of 55.8%.

[0094] The hollow fiber membrane substrate and the silane reagent solution are then contacted, and then dried and solidified to obtain a silanized hollow fiber membrane. The silane reagent solution is obtained by mixing a silane reagent, water and anhydrous low-carbon alcohol, and then pre-hydrolyzing. The pre-hydrolysis time is 17 hours. The volume ratio of silane reagent: water: anhydrous low-carbon alcohol is 3.9:5:91. The pH value of the silane reagent solution is 7.9. The silane reagent is methyl vinyl diethoxysilane. The anhydrous low-carbon alcohol is anhydrous methanol. The contact is immersion, and the immersion time is 150 seconds. The drying and solidification temperature is 110°C, and the time is 45 minutes, and the drying atmosphere is nitrogen. The amount of silane reagent solution is such that the thickness of the first and second silane layers is each independently 8.2 nm.

[0095] Subsequently, the solution containing the dehydration component is brought into contact with the silanized hollow fiber membrane substrate to coat the inner surface of the hollow fiber membrane with a first dehydration layer and the outer surface of the hollow fiber membrane with a second dehydration layer. The solution containing the dehydration component has a mass ratio of dehydration component: first initiator: first solvent of 7.1 : 0.3 : 93. The first solvent is toluene. The first initiator is benzoyl peroxide. The dehydration treatment component contains amide derivatives, pyrrole derivatives, and furan derivatives, where the molar ratio of amide derivatives: pyrrole derivatives: furan derivatives is 34.3 : 22.9 : 5.1. The amide derivatives are provided by N,N-methylenebisacrylamide. The pyrrole derivatives are provided by l-(3-buten-l-yl)-2-vinyl-lH-pyrrole. The furan derivatives are provided by 2-(l-propen-2-yl)furan. The dehydration treatment conditions include a liquid to solid volume ratio of the solution containing the dehydration component to the hollow fiber membrane after the silanization treatment of step (1) of 4.5, an immersion temperature of 74 °C, and a time of 2.3 h. The dehydration treatment is further followed by a dehydration post-treatment of the dehydration treatment product in a first post-treatment agent. The first post-treatment agent is anhydrous ethanol. The dehydration post-treatment conditions include an immersion time of 0.7 h, a drying temperature of 120 °C, and a drying time of 0.7 h. The first dehydration layer has an amide group content of 29.6 mmol / m 2 , a pyrrole group content of 19.7 mmol / m 2 , and a furan group content of 4.4 mmol / m 2 , per square meter of the inner surface area of the dry base hollow fiber membrane substrate. The second dehydration layer has an amide group content of 29.6 mmol / m 2 , a pyrrole group content of 19.7 mmol / m 2 , and a furan group content of 4.4 mmol / m 2 , per square meter of the outer surface area of the dry base hollow fiber membrane substrate. The first dehydration layer and the second dehydration layer each independently have a thickness of 10.3 nm.

[0096] Subsequently, the inner surface of the hollow fiber membrane after the dehydration treatment is coated with a first separation layer by a first separation treatment. The first separation treatment includes contacting a solution containing a first separation component with the inner surface of the hollow fiber membrane after the dehydration treatment. The solution containing the first separation component contains a polyether, a first separation component, a second initiator, and water, wherein the mass ratio of the polyether:the first separation component:the second initiator:the water is 100:10.2:0.7:1.9. The average molecular weight of the polyether is 1300. The second initiator is benzoyl peroxide. The first separation component contains a pyrrole derivative and a furan derivative, wherein the molar ratio of the pyrrole derivative:the furan derivative is 28.6:6.3. The pyrrole derivative is provided by 1-(3-buten-1-yl)-2-vinyl-1H-pyrrole. The furan derivative is provided by 2-(1-propen-2-yl)furan. The first separation treatment conditions include introducing the solution containing the first separation component into the inner cavity of the hollow fiber membrane after the dehydration treatment of step (2), the back pressure at the outlet of the inner cavity is 12 kg in terms of gage pressure, and then treating for 1.2 hours under a nitrogen atmosphere at 90°C; after cooling to room temperature, washing by immersion in hot acetonitrile at 60°C for 6 times, and then drying under a nitrogen atmosphere. The product of the first separation treatment can be subjected to a separation after-treatment in a second treatment agent. The second after-treatment agent is anhydrous acetone. The separation after-treatment conditions include an immersion time of 0.7 h, a drying temperature of 135°C, and a drying time of 0.7 h. In the first separation layer, the content of the pyrrole group is 24.3 mmol / m 2 , and the content of the furan group is 5.4 mmol / m 2 , per square meter of the inner surface area of the dry base hollow fiber membrane matrix. The thickness of the first separation layer is 13.2 nm.

[0097] The prepared low-carbon olefin hydrate product separation fiber membrane is used in the separation of low-carbon olefin hydrate products. The separation of the olefin hydrate product is carried out in a shell-and-tube olefin hydrate separator. The low-carbon olefin hydrate product separation fiber membrane is arranged in parallel in the olefin hydrate separator. After the low-carbon olefin hydrate reaction product is contacted with the outer surface of the low-carbon olefin hydrate product separation fiber membrane for separation, the inner cavity of the low-carbon olefin hydrate product separation fiber membrane obtains pure water for olefin hydration, and the outer side of the low-carbon olefin hydrate product separation fiber membrane is a low-carbon alcohol-rich aqueous solution. The separation conditions of the olefin hydrate product include a temperature of 30°C and a pressure of 1.8 MPa in terms of gage pressure. The rejection rate of the low-carbon alcohol during the separation process is 90.4%.

[0098] Example 2

[0099] The low-carbon olefin hydrate reaction product of Example 1 is selected.

[0100] In this example, the hollow fiber membrane substrate is prepared by the following method: first, a casting solution is prepared, then a hollow fiber precursor is prepared by a process of spinning-forming phase inversion, then dried and calcined to obtain a hollow ceramic fiber, the preparation conditions of the hollow ceramic fiber are as follows: polyether sulfone (average molecular weight 1600), N-methyl pyrrolidone, ceramic precursor (silicon dioxide), polyvinyl pyrrolidone K90, in a mass ratio of 9.8:66:325:4.8, stirred at 93°C for 57 hours, then left to stand for 10 hours to remove bubbles, to obtain a casting solution. The inner and outer gel baths of the spinneret are deionized water at 0.5°C, the inner diameter of the spinneret is 2.2 mm, the outer diameter is 3.2 mm, the casting solution flow rate is 2.4 ml / min, the inner casting solution pressure of the spinneret is 123 kPa (gauge pressure), the ambient temperature is 22°C, the ambient humidity is 58%, the casting solution exchanges solvents with the inner and outer gel baths and phase separates to form a hollow fiber precursor. The hollow fiber membrane precursor is washed with desalted water for 8 times, then dried with air at 28°C, then heated at a rate of 0.6°C / min to 1790°C, kept at this temperature for 7 hours, then naturally cooled to 22°C, to obtain a hollow ceramic fiber membrane substrate. The obtained hollow ceramic fiber has an inner diameter of 2 mm, an outer diameter of 3 mm, the pore size of the fiber membrane wall is 26 nm, and the porosity is 48%.

[0101] Then the hollow fiber membrane substrate and the silane reagent solution are contacted, and then dried and solidified to obtain a silanized hollow fiber membrane. The silane reagent solution is obtained by mixing the silane reagent, water and anhydrous low-carbon alcohol, and then pre-hydrolyzing. The pre-hydrolysis time is 23 hours. The volume ratio of silane reagent: water: anhydrous low-carbon alcohol is 5.3:5.6:90. The pH value of the silane reagent solution is 8.1. The silane reagent is methyl vinyl diethoxysilane. The anhydrous low-carbon alcohol is anhydrous methanol. The contact is immersion, and the immersion time is 180 seconds. The drying and solidification temperature is 115°C, and the time is 57 minutes, and the drying atmosphere is nitrogen. The amount of silane reagent solution is such that the thickness of the first and second silane layers is each independently 9.5 nm.

[0102] Subsequently, the solution containing the dehydration component is brought into contact with the silanized hollow fiber membrane substrate to coat the inner surface of the hollow fiber membrane with a first dehydration layer and the outer surface of the hollow fiber membrane with a second dehydration layer. The mass ratio of the dehydration component:the first initiator:the first solvent in the solution containing the dehydration component is 8.6:0.4:92. The first solvent is toluene. The first initiator is benzoyl peroxide. The dehydration component contains amide derivatives, pyrrole derivatives, and furan derivatives, wherein the molar ratio of the amide derivatives:the pyrrole derivatives:the furan derivatives is 44:28:6.3. The amide derivatives are provided by N,N-methylenebisacrylamide. The pyrrole derivatives are provided by 1-(3-buten-1-yl)-2-vinyl-1H-pyrrole. The furan derivatives are provided by 2-(1-propen-2-yl)furan. The dehydration treatment conditions include a liquid-to-solid volume ratio of the solution containing the dehydration component to the hollow fiber membrane after the silanization treatment of step (1) of 5, an immersion temperature of 83°C, and a time of 2.7 h. The dehydration treatment is further followed by a dehydration post-treatment of the dehydration treatment product in a first post-treatment agent. The first post-treatment agent is anhydrous ethanol. The dehydration post-treatment conditions include an immersion time of 0.8 h, a drying temperature of 125°C, and a drying time of 0.7 h. In the first dehydration layer, the content of amide groups is 38.2 mmol / m 2 , the content of pyrrole groups is 24.3 mmol / m 2 , and the content of furan groups is 5.4 mmol / m 2 , per square meter of the inner surface area of the dry base hollow fiber membrane substrate. In the second dehydration layer, the content of amide groups is 38.2 mmol / m 2 , the content of pyrrole groups is 24.3 mmol / m 2 , and the content of furan groups is 5.4 mmol / m 2 , per square meter of the outer surface area of the dry base hollow fiber membrane substrate. The thickness of the first dehydration layer and the second dehydration layer is independently 12.5 nm.

[0103] Subsequently, the inner surface of the hollow fiber membrane after the dehydration treatment is coated with a first separation layer by a first separation treatment. The first separation treatment includes contacting a solution containing a first separation component with the inner surface of the hollow fiber membrane after the dehydration treatment. The solution containing the first separation component contains a polyether, a first separation component, a second initiator, water, wherein the mass ratio of the polyether:the first separation component:the second initiator:water is 100:12.5:0.8:2.5. The average molecular weight of the polyether is 800. The second initiator is benzoyl peroxide. The first separation component contains a pyrrole derivative, a furan derivative, wherein the molar ratio of the pyrrole derivative:the furan derivative is 35.2:8.3. The pyrrole derivative is provided by 1-(3-buten-1-yl)-2-vinyl-1H-pyrrole. The furan derivative is provided by 2-(1-propen-2-yl)furan. The first separation treatment conditions include introducing the solution containing the first separation component into the lumen of the hollow fiber membrane after the dehydration treatment of step (2), the back pressure at the outlet of the lumen is 14 kg in terms of gage pressure, and then treating under a nitrogen atmosphere at 95°C for 1.4 hours; after cooling to room temperature, washing by immersion in hot acetonitrile at 68°C for 7 times, and then drying under a nitrogen atmosphere. The product of the first separation treatment can be subjected to a second post-treatment in a second post-treatment agent. The second post-treatment agent is anhydrous acetone. The second post-treatment conditions include an immersion time of 0.7 h, a drying temperature of 146°C, and a drying time of 0.8 h. In the first separation layer, the content of the pyrrole group is 28.8 mmol / m 2 , and the content of the furan group is 6.8 mmol / m 2 , per square meter of the inner surface area of the dry base of the hollow fiber membrane substrate.

[0104] The reaction method of Example 1 is followed, and the olefin hydration product separation conditions include a temperature of 23°C and a pressure of 3.1 MPa in terms of gage pressure. The rejection rate of the lower alcohol during the separation process is 93.4%.

[0105] Example 3

[0106] The lower olefin hydration reaction product of Example 1 is selected.

[0107] In this example, the hollow fiber membrane substrate is prepared by the following method: first, a casting solution is prepared, then a hollow fiber precursor is prepared by a process of spinning-forming and phase inversion, and then dried and calcined to obtain a hollow ceramic fiber, the preparation conditions of the hollow ceramic fiber are as follows: polyether sulfone (average molecular weight 3600), N-methyl pyrrolidone, ceramic precursor (silicon dioxide), polyvinyl pyrrolidone K90, in a mass ratio of 17:93:190:8.5, stirred at 78°C for 42 hours, and then left to stand for 8 hours to remove bubbles, to obtain a casting solution. The inner and outer gel baths of the spinneret are deionized water at 2.3°C, the inner diameter of the spinneret is 2.8 mm, the outer diameter is 3.8 mm, the casting solution flow rate is 5.1 ml / min, the inner casting solution pressure of the spinneret is 230 kPa (gauge pressure), the ambient temperature is 27°C, the ambient humidity is 47%, the casting solution exchanges solvents with the inner and outer gel baths and phase separates to form a hollow fiber blank. The hollow fiber membrane precursor is washed with desalted water for 5 times, then dried with air at 23°C, then heated at a rate of 0.8°C / min to 1630°C, kept at this temperature for 5 hours, then naturally cooled to 28°C, to obtain a hollow ceramic fiber membrane substrate. The obtained hollow ceramic fiber has an inner diameter of 2.6 mm, an outer diameter of 3.6 mm, a fiber membrane wall pore size of 70.3 nm, and a porosity of 63.5%.

[0108] Then the hollow fiber membrane substrate is contacted with a silane reagent solution, and then dried and solidified to obtain a silanized hollow fiber membrane. The silane reagent solution is obtained by mixing a silane reagent, water and anhydrous low-carbon alcohol, and then pre-hydrolyzing. The pre-hydrolysis time is 14 hours. The volume ratio of silane reagent: water: anhydrous low-carbon alcohol is 2.7:4.3:89. The pH value of the silane reagent solution is 7.6. The silane reagent is methyl vinyl diethoxysilane. The anhydrous low-carbon alcohol is anhydrous methanol. The contact is immersion, and the immersion time is 120 seconds. The drying and solidification temperature is 103°C, and the time is 34 minutes, and the drying atmosphere is nitrogen. The amount of silane reagent solution used is such that the thickness of the first and second silane layers is each independently 7.2 nm.

[0109] Subsequently, the solution containing the dehydration component is brought into contact with the silanized hollow fiber membrane substrate to coat the inner surface of the hollow fiber membrane with a first dehydration layer and the outer surface of the hollow fiber membrane with a second dehydration layer. The mass ratio of the dehydration component:the first initiator:the first solvent in the solution containing the dehydration component is 5.3:0.2:94. The first solvent is toluene. The first initiator is benzoyl peroxide. The dehydration component contains amide derivatives, pyrrole derivatives, and furan derivatives, wherein the molar ratio of the amide derivatives:the pyrrole derivatives:the furan derivatives is 24:18:3.7. The amide derivatives are provided by N,N-methylenebisacrylamide. The pyrrole derivatives are provided by l-(3-buten-l-yl)-2-vinyl-lH-pyrrole. The furan derivatives are provided by 2-(l-propen-2-yl)furan. The dehydration treatment conditions include a liquid-to-solid volume ratio of the solution containing the dehydration component to the hollow fiber membrane after the silanization treatment of step (1) of 4, an immersion temperature of 67 °C, and a time of 1.8 h. The dehydration treatment is further followed by a dehydration post-treatment of the dehydration treatment product in a first post-treatment agent. The first post-treatment agent is anhydrous ethanol. The dehydration post-treatment conditions include an immersion time of 0.6 h, a drying temperature of 113 °C, and a drying time of 0.6 h. In the first dehydration layer, the content of amide groups is 22.4 mmol / m 2 , the content of pyrrole groups is 16.8 mmol / m 2 , and the content of furan groups is 3.4 mmol / m 2 , per square meter of the inner surface area of the dry hollow fiber membrane substrate. In the second dehydration layer, the content of amide groups is 22.4 mmol / m 2 , the content of pyrrole groups is 16.3 mmol / m 2 , and the content of furan groups is 2.8 mmol / m 2 , per square meter of the outer surface area of the dry hollow fiber membrane substrate. The thickness of the first dehydration layer and the second dehydration layer is independently 9.7 nm.

[0110] Subsequently, the inner surface of the hollow fiber membrane after the dewatering treatment is coated with a first separation layer by a first separation treatment. The first separation treatment comprises contacting a solution containing a first separation component with the inner surface of the hollow fiber membrane after the dewatering treatment. The solution containing the first separation component comprises a polyether, a first separation component, a second initiator, and water, wherein the mass ratio of the polyether:the first separation component:the second initiator:the water is 100:8.2:0.6:1.4. The average molecular weight of the polyether is 1600. The second initiator is benzoyl peroxide. The first separation component contains a pyrrole derivative and a furan derivative, wherein the molar ratio of the pyrrole derivative:the furan derivative is 22.6:3.8. The pyrrole derivative is provided by 1-(3-buten-1-yl)-2-vinyl-1H-pyrrole. The furan derivative is provided by 2-(1-propen-2-yl)furan. The first separation treatment conditions comprise introducing the solution containing the first separation component into the inner cavity of the hollow fiber membrane after the dewatering treatment in step (2), the back pressure at the outlet of the inner cavity is 9 kg in terms of gage pressure, and then treating for 0.9 hours under a nitrogen atmosphere at 85°C; after cooling to room temperature, washing by immersion in hot acetonitrile at 54°C for 5 times, and then drying under a nitrogen atmosphere. The first separation component treatment product can be subjected to a separation after-treatment in a second after-treatment agent after the first separation component treatment. The second after-treatment agent is anhydrous acetone. The separation after-treatment conditions comprise an immersion time of 0.6 h, a drying temperature of 122°C, and a drying time of 0.6 h. In the first separation layer, the content of the pyrrole group is 19.1 mmol / m 2 , and the content of the furan group is 3.2 mmol / m 2 , per square meter of the inner surface area of the dry base hollow fiber membrane matrix. The thickness of the first separation layer is 11.2 nm.

[0111] According to the reaction method of Example 1, the olefin hydration product separation conditions comprise a temperature of 36°C and a pressure of 1.2 MPa in terms of gage pressure. The rejection rate of the low-carbon alcohol during the separation process is 86.7%.

[0112] Example 4

[0113] According to the method of Example 2, except that the composition of the low-carbon olefin hydration reaction product in this example comprises, in terms of mass percentage, sec-butanol 7.4%, di-sec-butyl ether 0.1%, and water 92.5%.

[0114] According to the reaction method of Example 2, the rejection rate of the low-carbon alcohol during the separation process in the olefin hydration separator is 85.7%.

[0115] Example 5

[0116] The method of Example 2 was followed, except that the composition of the low carbon olefin hydration reaction product in this example, by mass percentage, included: sec-butyl alcohol 34.8%, di-sec-butyl ether 0.4%, water 64.8%.

[0117] The method of Example 2 was followed, except that the composition of the low carbon olefin hydration reaction product in this example, by mass percentage, included: sec-butyl alcohol 34.8%, di-sec-butyl ether 0.4%, water 64.8%.

[0118] Example 6

[0119] The method of Example 2 was followed, except that the composition of the low carbon olefin hydration reaction product in this example, by mass percentage, included: sec-butyl alcohol 34.8%, di-sec-butyl ether 0.4%, water 64.8%.

[0120] The method of Example 2 was followed, except that the composition of the low carbon olefin hydration reaction product in this example, by mass percentage, included: sec-butyl alcohol 34.8%, di-sec-butyl ether 0.4%, water 64.8%.

[0121] Example 7

[0122] The method of Example 2 was followed, except that the composition of the low carbon olefin hydration reaction product in this example, by mass percentage, included: sec-butyl alcohol 34.8%, di-sec-butyl ether 0.4%, water 64.8%.

[0123] The method of Example 2 was followed, except that the composition of the low carbon olefin hydration reaction product in this example, by mass percentage, included: sec-butyl alcohol 34.8%, di-sec-butyl ether 0.4%, water 64.8%.

[0124] Example 8

[0125] The method of Example 3 was followed, except that this example omitted the post-dehydration treatment and the second post-treatment after the first separation component treatment. The hydration separation membrane prepared had product parameters that only the first separation layer changed. On the basis of the inner surface area of the dry base hollow fiber membrane matrix per square meter, in the first separation layer, the content of pyrrole groups was 18.9 mmol / m 2 , and the content of furan groups was 3.3 mmol / m 2 .

[0126] The thickness of the first separation layer was 10.9 nm.

[0127] The method of Example 3 was followed, except that this example omitted the post-dehydration treatment and the second post-treatment after the first separation component treatment. The hydration separation membrane prepared had product parameters that only the first separation layer changed. On the basis of the inner surface area of the dry base hollow fiber membrane matrix per square meter, in the first separation layer, the content of pyrrole groups was 18.9 mmol / m 2 , and the content of furan groups was 3.3 mmol / m 2 .

[0128] Comparative Example 1

[0129] The low carbon olefin hydration reaction product of Example 4 was selected.

[0130] The commercial nanofiltration membrane (Suez GE DK4040F50) was treated with water, and membrane separation was performed according to the reaction method of Example 2. The membrane separation pressure was 3.5 MPa in the olefin hydration separator, and the rejection rate of the low carbon alcohol during the separation process was 10.4%.

[0131] Comparative Example 2

[0132] The method of Example 3 was used, except that the first separation treatment was not performed.

[0133] The reaction raw materials and reaction method of Example 3 were used, and the membrane separation pressure was 3.5 MPa in the olefin hydration separator. The rejection rate of the low carbon alcohol during the separation process was 36.2%.

[0134] Comparative Example 3

[0135] The method of Example 3 was used, except that the dehydration treatment was not performed.

[0136] The reaction raw materials and reaction method of Example 3 were used, and the membrane separation pressure was 3.5 MPa in the olefin hydration separator. The rejection rate of the low carbon alcohol during the separation process was 31.4%.

[0137] The preferred embodiments of the present application are described in detail above, but the present application is not limited thereto. Within the technical concept of the present application, various simple modifications can be made to the technical solutions of the present application, including the combination of various technical features in any other suitable manner. These simple modifications and combinations should also be considered as disclosed by the present application and fall within the protection scope of the present application.

Claims

1. A fiber membrane for separating low-carbon olefin hydration products, characterized in that, The low-carbon olefin hydration product separation fiber membrane includes a hollow fiber membrane substrate, a first silane layer, a first dehydration layer, and a first separation layer sequentially coated on the inner surface of the hollow fiber membrane substrate from the inside out, and a second silane layer and a second dehydration layer sequentially coated on the outer surface of the hollow fiber membrane substrate from the inside out; the first dehydration layer and the second dehydration layer each independently contain amide groups, pyrrole groups, and furan groups; the first separation layer contains pyrrole groups and furan groups.

2. The low-carbon olefin hydration product separation fiber membrane according to claim 1, wherein, The hollow fiber membrane substrate is a hollow ceramic fiber membrane.

3. The low-carbon olefin hydration product separation fiber membrane according to claim 1, wherein, The hollow fiber membrane substrate has an inner diameter of 1.8-2.8 mm, an outer diameter of 2.9-4.8 mm, a pore size of 25-75 nm, and a porosity of 45-65%.

4. The low-carbon olefin hydration product separation fiber membrane according to claim 1, wherein, The hollow fiber membrane substrate is made of silicon dioxide and / or aluminum oxide.

5. The low-carbon olefin hydration product separation fiber membrane according to any one of claims 1-4, wherein, The thickness of the first silane layer and the second silane layer are each independently 6-10 nm.

6. The low-carbon olefin hydration product separation fiber membrane according to any one of claims 1-4, wherein, The first silane layer and the second silane layer are each independently provided by at least one of 2-butenyltriethoxysilane, methylvinyldiethoxysilane and allyldimethoxysilane.

7. The low-carbon olefin hydration product separation fiber membrane according to any one of claims 1-4, wherein, Based on the inner surface area of ​​the dry-based hollow fiber membrane matrix per square meter, the content of amide groups in the first dehydration layer is 20-39 mmol / m². 2 The content of pyrrole groups is 15-25 mmol / m³. 2 The furanyl content is 2.5-6 mmol / m³. 2 .

8. The low-carbon olefin hydration product separation fiber membrane according to any one of claims 1-4, wherein, Based on the surface area of ​​the dry-based hollow fiber membrane matrix per square meter, the content of amide groups in the second dehydration layer is 20-39 mmol / m². 2 The content of pyrrole groups is 15-25 mmol / m³. 2 The furanyl content is 2.5-6 mmol / m³. 2 .

9. The low-carbon olefin hydration product separation fiber membrane according to any one of claims 1-4, wherein, The thickness of the first dehydration layer and the second dehydration layer are each 8-13 nm independently.

10. The low-carbon olefin hydration product separation fiber membrane according to any one of claims 1-4, wherein, Based on the inner surface area of ​​the dry-based hollow fiber membrane matrix per square meter, the content of pyrrole groups in the first separation layer is 18-30 mmol / m². 2 The furanyl content is 3-8 mmol / m 2 .

11. The low-carbon olefin hydration product separation fiber membrane according to any one of claims 1-4, wherein, The thickness of the first separation layer is 10-16 nm.

12. A method for preparing a fiber membrane for separating low-carbon olefin hydration products, wherein, The method includes: (1) The hollow fiber membrane substrate is subjected to silanization treatment to obtain silanized hollow fiber membrane; (2) The silanized hollow fiber membrane described in step (1) is dehydrated using a solution containing dehydrating components to obtain a dehydrated hollow fiber membrane; (3) The inner surface of the hollow fiber membrane after dehydration treatment in step (2) is subjected to a first separation treatment using a solution containing the first separation component to obtain a low-carbon olefin hydration product separation fiber membrane. The dehydration component contains amide, pyrrole, and furanyl groups, and the first separation component contains pyrrole and furanyl groups.

13. The preparation method according to claim 12, wherein, In step (1), the silanization process coats the inner and outer surfaces of the hollow fiber membrane substrate with a first silane layer and a second silane layer, respectively, with the thickness of the first silane layer and the second silane layer being 6-10 nm each independently.

14. The preparation method according to claim 13, wherein, In step (1), the silanization process includes: contacting the silane reagent solution with the hollow fiber membrane substrate, and then drying and curing it.

15. The preparation method according to claim 14, wherein, The silane reagent solution is obtained by pre-hydrolysis of silane reagent, water, and low-carbon alcohol.

16. According to the preparation method of claim 15, the volume ratio of silane reagent: water: lower alcohol is (2.4-5.4):(4-6):(88-94).

17. The preparation method according to claim 15, wherein, The silane reagent is selected from at least one of 2-butenyltriethoxysilane, methylvinyldiethoxysilane, and allyldimethoxysilane.

18. The preparation method according to any one of claims 12-17, wherein, In step (2), the dehydration treatment causes the inner and outer surfaces of the silanized hollow fiber membrane to be coated with a first dehydration layer and a second dehydration layer, respectively. The first and second dehydration layers each contain amide groups, pyrrole groups, and furan groups independently.

19. The preparation method according to claim 18, wherein, Based on the inner surface area of ​​the dry-based hollow fiber membrane matrix per square meter, the content of amide groups in the first dehydration layer is 20-39 mmol / m². 2 The content of pyrrole groups is 15-25 mmol / m³. 2 The furanyl content is 2.5-6 mmol / m³. 2 .

20. The preparation method according to claim 18, wherein, Based on the surface area of ​​the dry-based hollow fiber membrane matrix per square meter, the content of amide groups in the second dehydration layer is 20-39 mmol / m². 2 The content of pyrrole groups is 15-25 mmol / m³. 2 The furanyl content is 2.5-6 mmol / m³. 2 .

21. The preparation method according to any one of claims 12-17, wherein, In step (2), the solution containing the dehydration treatment component contains the dehydration component, the first initiator, and the first solvent.

22. The preparation method according to claim 21, wherein, In step (2), the dehydration treatment components are provided by amide derivatives, pyrrole derivatives and furan derivatives.

23. The preparation method according to claim 22, wherein, The molar ratio of amide derivatives: pyrrole derivatives: furan derivatives is (23-45): (17-29): (3-7).

24. The preparation method according to claim 22, wherein, The amide group is provided by an amide derivative.

25. The preparation method according to claim 24, wherein, The amide derivative is selected from at least one of N,N'-dihydroxyethylbisacrylamide, N,N-methylenebisacrylamide, and hexamethylenebisacrylamide.

26. The preparation method according to claim 22, wherein, The pyrrole group is provided by a pyrrole derivative.

27. The preparation method according to claim 26, wherein, The pyrrole derivatives are selected from at least one of 3-isopropenyl-1-methyl-pyrrole, 1-(3-buten-1-yl)-2-vinyl-1H-pyrrole, and 5-allyl-4-methoxy-1,5-dihydro-2H-pyrrole-2-one.

28. The preparation method according to claim 22, wherein, The furanyl group is provided by furan derivatives.

29. The preparation method according to claim 28, wherein, The furan derivatives are 2-(1-propen-2-yl)furan and / or 2-(2-pentenyl)furan.

30. The preparation method according to claim 21, wherein, In step (2), the first solvent is selected from at least one of toluene, p-xylene, m-xylene and o-xylene.

31. The preparation method according to claim 21, wherein, In step (2), the first initiator is selected from at least one of azo, organic peroxide, inorganic peroxide and redox initiators.

32. The preparation method according to claim 31, wherein, In step (2), the first initiator is at least one of azobisisobutyronitrile, benzoyl peroxide, potassium persulfate and hydrogen peroxide.

33. The preparation method according to claim 21, wherein, In step (2), the mass ratio of the dehydrating component to the first initiator to the first solvent in the solution containing the dehydrating component is (5-9):(0.1-0.5):(90-96).

34. The preparation method according to claim 21, wherein, In step (2), the conditions for the dehydration treatment include: the liquid-to-solid volume ratio of the solution containing the dehydration component to the silanized hollow fiber membrane in step (1) is 3-6, the soaking temperature is 63-85℃, and the soaking time is 1.5-3h.

35. The preparation method according to claim 21, wherein, Step (2) further includes dehydrating the dehydrated product in a first post-treatment agent.

36. The preparation method according to claim 35, wherein, The first post-treatment agent is selected from at least one of anhydrous ethanol, anhydrous methanol and anhydrous acetone.

37. The preparation method according to claim 36, wherein, The first post-treatment agent is anhydrous ethanol.

38. The preparation method according to claim 35, wherein, The conditions for the dehydration post-treatment include: soaking time of 0.5-1h, drying temperature of 110-130℃, and drying time of 0.5-1h.

39. The preparation method according to any one of claims 12-17, wherein, In step (3), the first separation process coats the inner surface of the hollow fiber membrane after the dehydration process in step (2) with a first separation layer, which contains pyrrole groups and furan groups.

40. The preparation method according to claim 39, wherein, Based on the inner surface area of ​​the dry-based hollow fiber membrane matrix per square meter, the content of pyrrole groups in the first separation layer is 18-30 mmol / m². 2 The furanyl content is 3-8 mmol / m 2 .

41. The preparation method according to any one of claims 12-17, wherein, In step (3), the solution containing the first separation component contains polyether, the first separation component, the second initiator and water.

42. The preparation method according to claim 41, wherein, In the solution containing the first separation component, the mass ratio of polyether: first separation component: second initiator: water is 100: (7-13): (0.5-0.9): (1.2-2.7).

43. The preparation method according to claim 41, wherein, The polyether has an average molecular weight of 700-1800.

44. The preparation method according to claim 41, wherein, In step (3), the first separated component is provided by pyrrole derivatives and furan derivatives.

45. The preparation method according to claim 44, wherein, In step (3), the molar ratio of pyrrole derivatives to furan derivatives in the solution of the first separated component is (21-36):(3.5-9).

46. ​​The preparation method according to claim 41, wherein, In step (3), the first separation process includes: introducing a solution containing the first separation component into the inner cavity of the hollow fiber membrane after the dehydration treatment in step (2), with the back pressure at the outlet of the inner cavity being 8-15 kg as measured by a gauge.

47. The preparation method according to claim 41, wherein, Step (3) also includes further processing the first separation product in a second post-processing agent.

48. The preparation method according to claim 47, wherein, The second post-treatment agent is selected from at least one of anhydrous ethanol, anhydrous acetone and anhydrous methanol.

49. The preparation method according to claim 48, wherein, The second post-treatment agent is anhydrous acetone.

50. The preparation method according to claim 47, wherein, The conditions for post-separation treatment include: soaking time of 0.5-1 h, drying temperature of 120-150 °C, and drying time of 0.5-1 h.

51. The application of the low-carbon olefin hydration product separation fiber membrane according to any one of claims 1-11 or the low-carbon olefin hydration product separation fiber membrane prepared by the preparation method according to any one of claims 12-50 in the separation of low-carbon olefin hydration products.

52. The application according to claim 51, wherein, The separation of low-carbon olefin hydration products includes: in the presence of a low-carbon olefin hydration product separation fiber membrane, the low-carbon olefin hydration products come into contact with the outer surface of the low-carbon olefin hydration product separation fiber membrane, and the inner cavity of the low-carbon olefin hydration product separation fiber membrane is filled with pure water and the outer side of the low-carbon olefin hydration product separation fiber membrane is filled with an aqueous solution containing low-carbon alcohols.

53. The application according to claim 52, wherein, The low-carbon olefin hydration product is a low-carbon olefin hydration product containing low-carbon alcohols synthesized by the hydration reaction of C3 and / or C4 low-carbon olefins.

54. The application according to claim 52, wherein, Based on the total amount of low-carbon olefin hydration products containing low-carbon alcohols, the content of low-carbon alcohols in the low-carbon olefin hydration products is 0.5-90% by mass.

55. The application according to claim 52, wherein, The contact conditions include a temperature of 20-40°C and a pressure of 0.5-4 MPa measured by a gauge.