A modified hollow ceramic fiber, its preparation method and application

Abstract

The present invention discloses a modified hollow ceramic fiber, a preparation method thereof and an application. The modified hollow ceramic fiber comprises a hollow ceramic fiber, and the inner surface of the hollow ceramic fiber includes a silane layer, a first modification layer and a second modification layer from outside to inside; the first modification layer contains phenyl; the second modification layer contains secondary amino groups and primary amino groups. The preparation method of the modified hollow ceramic fiber comprises: subjecting the hollow ceramic fiber to silanization treatment to obtain a silanized hollow ceramic fiber; then successively performing a first modification treatment, a second modification treatment and an activation treatment on the obtained silanized hollow ceramic fiber to obtain the modified hollow ceramic fiber. By using the modified hollow ceramic fiber of the present invention, sulfur-containing impurities that affect the activity of the ethylbenzene alkylation catalyst in dry gas can be efficiently removed, the accumulation of sulfur-containing impurities in the catalytic system can be reduced, the service life of the ethylbenzene alkylation catalyst can be effectively prolonged, and the production cost of ethylbenzene can be reduced. It can be used in the industrial production of dry gas to ethylbenzene units.

Description

Technical Field

[0001] The present invention relates to the technical field of ethylbenzene production from dry gas, and particularly relates to a modified hollow ceramic fiber, a preparation method thereof, and an application thereof in removing impurities in dry gas. Background Art

[0002] Dry gas refers to the tail gas that cannot be liquefied during the petroleum refining process, mainly originating from the secondary processing of crude oil, and is generally used as fuel. In order to make full use of the dilute ethylene in dry gas, improve the utilization rate of petroleum resources, and at the same time solve the current shortage of the ethylbenzene / styrene market, various countries have developed the process of producing ethylbenzene from dry gas. Generally, in the presence of a catalyst, at a reaction temperature of 200°C - 500°C, ethylene and a small amount of propylene and butene in dry gas react with benzene to form ethylbenzene, propylbenzene, butylbenzene, and polyalkylbenzene, etc.

[0003] Ethylbenzene alkylation catalysts generally use acidic molecular sieves. Since dry gas contains relatively high levels of sulfur-containing impurities, due to their strong polarity, they are easily adsorbed on the active centers on the surface of the catalyst, causing catalyst deactivation and significantly shortening the operation cycle of the ethylbenzene alkylation catalyst. Therefore, dry gas needs to be desulfurized before entering the ethylbenzene production unit from dilute ethylene to control the H2S content. However, when the desulfurization device fluctuates, the volume fraction of H2S in catalytic dry gas will exceed 100×10 -6 -6, and even up to 20000×10 -6 -6.

[0004] The article "Summary of the Intermediate Test on the Selective Removal of H2S by Aqueous Methyl Diethanolamine Solution under Pressure" (Chemical Engineering of Oil and Gas, No. 2, 1987) discloses a method for removing natural gas containing hydrogen sulfide using an aqueous methyl diethanolamine solution in an absorption tower, reducing the hydrogen sulfide content in the purified gas to 10 mg / m 3 3. This method significantly reduces the hydrogen sulfide content in natural gas. However, using a conventional absorption tower operation will result in a relatively small removal elasticity of hydrogen sulfide, and the removal depth of hydrogen sulfide is generally average, making it difficult to meet the requirements of working conditions that are sensitive to the hydrogen sulfide content.

[0005] The article "Industrial Application of the Removal of H2S by the Hypergravity Complex Iron Method" (Chemical Industry and Engineering Technology, Vol. 35, No. 2, 2014) discloses a method for removing hydrogen sulfide-containing associated gas from oilfields using complex iron in a hypergravity machine, with the hydrogen sulfide concentration in the desulfurized associated gas being less than 20 mg / m 2 3. The removal depth of hydrogen sulfide by this method is not as good as the research results disclosed in "Summary of the Intermediate Test on the Selective Removal of H2S by Aqueous Methyl Diethanolamine Solution under Pressure" (Chemical Engineering of Oil and Gas, No. 2, 1987), and it is still difficult to apply to working conditions that are sensitive to the hydrogen sulfide content.

[0006] Patent CN103756743A discloses a method for removing hydrogen sulfide from low-content hydrogen sulfide raw gas on an offshore platform, wherein the hydrogen sulfide content in the hydrogen sulfide raw gas is ≤300ppm, and the outlet hydrogen sulfide concentration is about 0ppm (undetectable). This method has a high depth of hydrogen sulfide removal, but is generally only applicable to occasions where the hydrogen sulfide content in the raw material is low. When the hydrogen sulfide content in the raw material is high, the depth of hydrogen sulfide removal cannot be guaranteed.

[0007] Patent CN102151476A discloses a method for oxidative removal of hydrogen sulfide in the gas phase under a hypergravity field, which involves contacting a desulfurizer and a hydrogen sulfide-containing gas in a countercurrent or crosscurrent manner in a desulfurization hypergravity machine to remove hydrogen sulfide from catalytic cracking dry gas, thereby reducing the concentration of hydrogen sulfide from 10,000 ppm to 20 ppm. The depth of hydrogen sulfide removal by this method is still inferior to the research results disclosed in "Summary of Intermediate Tests on Selective Removal of H2S from Methyldiethanolamine Aqueous Solution under Pressure" (Petroleum and Natural Gas Chemical Industry, Issue 2, 1987), and is difficult to apply to working conditions that are sensitive to hydrogen sulfide content.

[0008] In summary, the existing technologies for removing sulfur-containing impurities mainly have the following problems: low operational flexibility and insufficient removal depth, which in turn lead to continuous slow deactivation or rapid deactivation of the alkylation catalyst. Therefore, continuous deep and stable removal of sulfur-containing impurities in dry gas is one of the important issues to be solved in ethylbenzene units related to high-sulfur crude oil refining. Summary of the invention

[0009] The technical problem to be solved by the present invention is that the content of sulfur-containing impurities in dry gas is high and difficult to remove in the prior art, and a modified hollow ceramic fiber and a preparation method and application thereof are provided. The modified hollow ceramic fiber of the present invention is used to separate sulfur-containing impurities in dry gas that affect the activity of ethylbenzene alkylation catalyst, effectively eliminate the cumulative effect of trace sulfur-containing impurities on the catalyst, which is conducive to extending the operating cycle of the alkylation catalyst and realizing low-cost and continuous production of ethylbenzene.

[0010] The first aspect of the present invention provides a modified hollow ceramic fiber, wherein the modified hollow ceramic fiber comprises a hollow ceramic fiber, the inner surface of which comprises a silane layer, a first modified layer and a second modified layer from the outside to the inside; the first modified layer contains a phenyl group; and the second modified layer contains a secondary amine group and a primary amine group.

[0011] In the above technical solution, in the silane layer, the molar ratio of silicon ether group to silicon carbon group is 0.6-1.0, and the thickness of the silane layer is 10-30 microns.

[0012] In the above technical solution, the phenyl content in the first modified layer is 0.13 to 0.29 mol / m 2 , the thickness of the first modified layer is 3 to 6 microns.

[0013] In the above technical solution, in the second modified layer, the content of secondary amino groups is 0.30 - 0.50 mol / m 2 , and the content of primary amino groups is 0.09 - 0.22 mol / m 2 ; preferably, the second modified layer further contains tertiary amino groups, and the content of tertiary amino groups is 0.07 - 0.14 mol / m 2 .

[0014] In the above technical solution, the inner surface of the second modified layer further includes a third modified layer. In the third modified layer, the content of secondary amino groups is 8 - 30 mmol / m 2 , the content of imino groups is 3.4 - 12.9 mmol / m 2 , and the content of methoxy groups is 9.6 - 39.0 mmol / m 2 .

[0015] In the above technical solution, the inner diameter of the modified hollow ceramic fiber is 0.3 - 1.0 mm, the outer diameter is 1.3 - 2.0 mm, the pore diameter of the fiber membrane wall is 500 - 1000 nm, and the porosity is 50% - 70%. The material is preferably silica or alumina.

[0016] In the above technical solution, the silanization reagent used for the silane layer is selected from at least one of γ-methacryloxypropylmethyldiethoxysilane, γ-methacryloxypropylmethyldimethoxysilane, etc.

[0017] In the above technical solution, the first modifier used for the first modified layer includes a first modifying component (the first modifying component is selected from at least one of 3-(3,5-dichlorophenyl)-1-propene, 1-(3-buten-1-yl)-2,4-dichlorobenzene, 3-(3,4-dichlorophenyl)-1-propene, and is preferably 1-(3-buten-1-yl)-2,4-dichlorobenzene), benzoyl peroxide and a solvent; the solvent is selected from at least one of toluene, p-xylene, m-xylene, o-xylene.

[0018] In the above technical solution, the second modifier used for the second modified layer includes a second modifying component (the second modifying component is selected from at least one of N1-(2-aminoethyl)-N1-(2-aminophenyl)-1,2-benzenediamine, N,N-bis(4-aminophenyl)-1,4-benzenediamine, 3,5-diamino-N-(4-aminophenyl)benzamide, and is preferably N,N-bis(4-aminophenyl)-1,4-benzenediamine), polyoxyethylene polyoxypropylene ether, a catalyst and a solvent; the catalyst is selected from one of Lewis acids or Lewis bases, and is preferably at least one of anhydrous zinc chloride, anhydrous tin tetrachloride, anhydrous aluminum chloride; the solvent is selected from at least one of toluene, p-xylene, m-xylene, o-xylene.

[0019] In the above technical solution, the third modifier used in the third modification layer includes a third modification component (the third modification component is selected from at least one of 2-[2-(2,6-dichlorophenyl)ethyl]hydrazinecarboxamidine, N-amidino-2-(2,6-dichlorophenyl)acetamide, and N1,N2-bis(4-chlorophenyl)acetamidine, and is preferably N-amidino-2-(2,6-dichlorophenyl)acetamide), a diluent, 3,5-dichloro-2-methoxyaniline, and a catalyst; the diluent is at least one of tetrahydrofuran, dichloromethane, dichloroethane, chloroform, and trichloroethane; the catalyst is selected from one of Lewis acids or Lewis bases, and is preferably at least one of anhydrous zinc chloride, anhydrous stannic chloride, and anhydrous aluminum chloride.

[0020] In the above technical solution, the contents of phenyl in the first modification layer, secondary amino group, primary amino group, and tertiary amino group in the second modification layer, and secondary amino group, imino group, and methoxy group in the third modification layer are all based on the inner surface area of the hollow ceramic fiber per square meter.

[0021] The second aspect of the present invention provides a method for preparing the above modified hollow ceramic fiber, including:

[0022] (1) Perform silanization treatment on the inner surface of the hollow ceramic fiber to obtain silanized hollow ceramic fiber;

[0023] (2) The silanized hollow ceramic fiber obtained in step (1) is subjected to the first modification treatment;

[0024] (3) The hollow ceramic fiber obtained in step (2) is subjected to the second modification treatment;

[0025] (4) The hollow ceramic fiber obtained in step (3) is subjected to activation treatment to obtain modified hollow ceramic fiber.

[0026] In the above technical solution, the inner diameter of the hollow ceramic fiber in step (1) is 0.3 to 1.0 mm, the outer diameter is 1.3 to 2.0 mm, the pore diameter of the fiber membrane wall is 500 to 1000 nm, and the porosity is 50% to 70%. The material is preferably silica or alumina. The hollow ceramic fiber can be prepared by a conventional method in the art. For example, a casting solution can be first prepared, and then a hollow fiber preform can be obtained by a spinning and phase inversion method. Subsequently, the hollow ceramic fiber can be obtained through drying and roasting. Generally, the preparation conditions of the hollow ceramic fiber are as follows: polyethersulfone (molecular weight of 40,000 to 50,000), N-methylpyrrolidone, ceramic precursor (such as silica or alumina), polyvinylpyrrolidone K90, with a mass ratio of (10 to 20):(100 to 160):(150 to 250):(1 to 3). Stir at 60 to 90 °C for 20 to 40 hours, and then stand for defoaming for 6 to 10 hours to obtain a casting solution. The inner and outer coagulation baths of the spinneret are deionized water at 0 to 3 °C. The inner diameter of the spinneret is 0.3 to 1.0 mm, the outer diameter is 1.3 to 2.0 mm, the flow rate of the casting solution is 7 to 10 ml / min, the pressure of the casting solution in the spinneret is 100 to 300 kPa (gauge pressure), the ambient temperature is 20 to 30 °C, the ambient humidity is 50% to 70%, and the solvent exchange and phase separation curing occur between the casting solution and the inner and outer coagulation baths to form a hollow fiber preform. After the hollow fiber preform is washed 4 to 8 times with demineralized water, it is dried with air at 20 to 30 °C, and then the temperature is raised to 1600 to 1800 °C at a rate of 0.5 to 1 °C / min, held at a constant temperature for 3 to 6 hours, and then naturally cooled to 20 to 30 °C to obtain the hollow ceramic fiber.

[0027] In the above technical solution, the silanized hollow ceramic fiber obtained in step (1) is a hollow ceramic fiber with a silane film with a thickness of 10 to 30 μm coated on the inner surface.

[0028] In the above technical solution, the silanization treatment of the hollow ceramic fibers in step (1) can adopt the conventional flow modification method in the art. The process includes: treating the inner surface of the hollow ceramic fibers with a solution of a silane reagent (selected from at least one of γ-methacryloxypropylmethyldiethoxysilane, γ-methacryloxypropylmethyldimethoxysilane, etc.), and then drying and curing to obtain silanized hollow ceramic fibers. The silane treatment conditions are as follows: the composition of the silane reagent solution, by volume fraction, is silane reagent: deionized water: absolute ethanol = (4 - 8):(12 - 16):(80 - 90), the pH value is 7.0 - 8.5, and the pre-hydrolysis time is 20 - 40 hours. The hollow ceramic fibers are first passed through petroleum ether with a boiling point of 80 - 90 °C at an inner surface fluid linear velocity of 0.05 - 0.26 m / s for continuous replacement for 2 - 3 hours, and then the silane reagent solution is passed through at an inner surface fluid linear velocity of 0.2 - 0.4 m / s, and the feeding time is 1 - 5 minutes. The drying and curing temperature is 110 - 130 °C, the drying time is 30 - 50 minutes, and the drying atmosphere is nitrogen. The replacement and drying of petroleum ether and the silane reagent solution are continuously processed 3 - 5 times.

[0029] In the above technical solution, the first modifier used in the first modification treatment in step (2) is a first modification component (the first modification component is selected from at least one of 3-(3,5-dichlorophenyl)-1-propene, 1-(3-buten-1-yl)-2,4-dichlorobenzene, 3-(3,4-dichlorophenyl)-1-propene, and preferably 1-(3-buten-1-yl)-2,4-dichlorobenzene), benzoyl peroxide, and a solvent. Preferably, the first modification component, benzoyl peroxide, and the solvent, by mass fraction, are first modification component: benzoyl peroxide: solvent = (15 - 25):(1 - 3):(100 - 200). The solvent is selected from at least one of toluene, p-xylene, m-xylene, and o-xylene.

[0030] In the above technical solution, the treatment conditions of the first modification treatment in step (2) are as follows: controlling the inner surface fluid linear velocity of the first modifier in the silanized hollow ceramic fiber membrane obtained in step (1) to be 0.4 - 0.8 m / s, the treatment temperature to be 30 °C - 60 °C, and the treatment time to be 2 - 4 hours. After treating the hollow ceramic fibers with the first modifier, a first-modified silanized hollow ceramic fiber intermediate is obtained.

[0031] In the above technical solution, preferably, in step (2), after the first modification treatment of the hollow ceramic fibers obtained in step (1), a first post-modification treatment is carried out to obtain a first post-modification treated silanized hollow ceramic fiber intermediate.

[0032] In the above technical solution, preferably, in step (2), the first modified post-treatment agent may be one or more of anhydrous methanol, anhydrous ethanol, and anhydrous acetone, and the preferred first modified post-treatment agent is anhydrous ethanol.

[0033] In the above technical solution, preferably, in step (2), the first modified post-treatment can be carried out by a flowing method, and the conditions of the first modified post-treatment are as follows: the first modified post-treatment agent is transported into the inner cavity of the hollow ceramic fiber, the temperature is 60°C to 80°C, the fluid linear velocity of the first modified post-treatment agent on the inner surface of the hollow fiber membrane is controlled to be 0.3 to 0.7 m / s, the continuous treatment time is 1 to 3 hours, and after the first post-treatment, it is purged and dried with an inert gas (such as nitrogen) at 110°C to 130°C for 0.5 to 1.0 hour.

[0034] In the above technical solution, in step (3), the hollow ceramic fiber obtained in step (2) (the first modified silanized hollow ceramic fiber intermediate and / or the first modified post-treated silanized hollow ceramic fiber intermediate) is subjected to a second modification treatment to obtain a second modified silanized hollow ceramic fiber intermediate.

[0035] In the above technical solution, preferably, in step (3), when introduced into the modified hollow ceramic fiber through the second modification treatment, the content of secondary amino groups is 0.30 to 0.50 mol / m 2 , and the content of primary amino groups is 0.09 to 0.22 mol / m 2 , preferably, the second modified layer further contains tertiary amino groups, and the content of tertiary amino groups is 0.07 to 0.14 mol / m 2 .

[0036] In the above technical solution, in step (3), the second modifier is a second modified component (the second modified component is selected from at least one of N1-(2-aminoethyl)-N1-(2-aminophenyl)-1,2-benzenediamine, N,N-bis(4-aminophenyl)-1,4-benzenediamine, 3,5-diamino-N-(4-aminophenyl)benzamide, and preferably N,N-bis(4-aminophenyl)-1,4-benzenediamine), polyoxyethylene polyoxypropylene ether, a catalyst, and a solvent; the catalyst is selected from one of Lewis acids or Lewis bases, and preferably at least one of anhydrous zinc chloride, anhydrous stannic chloride, and anhydrous aluminum chloride; the solvent is selected from at least one of toluene, p-xylene, m-xylene, and o-xylene. Preferably, for the second modified component, the catalyst, and the solvent, by mass parts, the second modified component: polyoxyethylene polyoxypropylene ether: catalyst: solvent = (20 to 30): (2 to 6): (10 to 20): (200 to 300). Among them, the average molecular weight of polyoxyethylene polyoxypropylene ether is 1500 to 4000.

[0037] In the above technical solution, for the second modification treatment described in step (3), the treatment conditions of the second modification treatment are as follows: control the fluid linear velocity of the second modifier on the inner surface of the silylated hollow ceramic fiber obtained in step (2) to be 0.6 to 1.4 m / s, the treatment temperature to be 55°C to 75°C, the treatment time to be 2 to 4 hours, and the treatment pressure (gauge pressure) to be 300 to 600 kPa.

[0038] In the above technical solution, preferably, in step (3), after the hollow ceramic fiber obtained in step (2) is subjected to the second modification treatment, it is subjected to a third modification treatment; after being introduced into the hollow ceramic fiber through the third modification treatment, the content of secondary amino groups is 8 to 30 mmol / m 2 , and the content of imino groups is 3.4 to 12.9 mmol / m 2 , and the content of methoxy groups is 9.6 to 39.0 mmol / m 2 .

[0039] In the above technical solution, preferably, in step (3), the second modified silylated hollow ceramic fiber intermediate is subjected to a third modification treatment to obtain a third modified silylated hollow ceramic fiber intermediate.

[0040] In the above technical solution, preferably, in step (3), the third modifier used for the third modification treatment is a third modification component (the third modification component is selected from at least one of 2-[2-(2,6-dichlorophenyl)ethyl]hydrazinecarboxamidine, N-amidino-2-(2,6-dichlorophenyl)acetamide, and N1,N2-bis(4-chlorophenyl)acetamidine, preferably N-amidino-2-(2,6-dichlorophenyl)acetamide), a diluent, 3,5-dichloro-2-methoxyaniline, and a catalyst; the diluent is at least one of tetrahydrofuran, dichloromethane, dichloroethane, chloroform, and trichloroethane; the catalyst is selected from one of Lewis acids or Lewis bases, preferably at least one of anhydrous zinc chloride, anhydrous tin tetrachloride, and anhydrous aluminum chloride. Preferably, for the third modification component, the diluent, 3,5-dichloro-2-methoxyaniline, and the catalyst, by mass parts, the third modification component: the diluent: 3,5-dichloro-2-methoxyaniline: the catalyst = (10 to 20): (200 to 300): (40 to 80): (10 to 20).

[0041] In the above technical solution, preferably, in step (3), the treatment conditions of the third modification treatment are as follows: control the fluid linear velocity of the third modifier on the inner surface of the silylated hollow ceramic fiber obtained in step (3) to be 1.5 to 3 m / s, the treatment temperature to be 60°C to 75°C, the treatment time to be 6 to 8 hours, and the treatment pressure (gauge pressure) to be 300 to 500 kPa.

[0042] In the above technical solution, preferably, in step (3), after the second modification treatment or the third modification treatment, a third post-modification treatment is carried out to obtain a pre-activated modified silanized hollow ceramic fiber intermediate.

[0043] In the above technical solution, preferably, in step (3), the pre-activator used in the third post-modification treatment is anhydrous ethanol.

[0044] In the above technical solution, preferably, in step (3), the conditions of the third post-modification treatment are as follows: the pre-activator is transported into the inner cavity of the hollow ceramic fiber, the temperature is 60°C to 80°C, the fluid linear velocity of the pre-activator on the inner surface of the hollow fiber membrane is controlled to be 0.3 to 0.7 m / s, the continuous treatment time is 1 to 3 hours, and after the third post-treatment, it is purged and dried with an inert gas (such as nitrogen) at 110°C to 130°C for 0.5 to 1.0 hour.

[0045] In the above technical solution, in step (4), the pre-activated modified silanized hollow ceramic fiber intermediate is subjected to an activation treatment, preferably including desalted water treatment, to obtain modified hollow ceramic fibers. The activator is an alkaline aqueous solution with a mass concentration of 2% to 10%; the alkaline aqueous solution is an inorganic base solution and / or an organic base solution, preferably at least one of a sodium hydroxide aqueous solution and a potassium hydroxide aqueous solution. The treatment conditions of the activator treatment are as follows: the alkaline aqueous solution is transported into the inner cavity of the hollow ceramic fiber by a conventional pump, the treatment temperature is 30°C to 50°C, the fluid linear velocity of the activator on the inner surface of the hollow fiber membrane is controlled to be 0.1 to 0.3 m / s, and the treatment time is 2 to 3 hours. The desalted water treatment is to transport desalted water into the inner cavity of the hollow ceramic fiber, the surface fluid linear velocity is 0.1 to 0.3 m / s, and the treatment temperature is 40°C to 60°C.

[0046] The third aspect of the present invention provides an application of the modified hollow ceramic fibers provided in the first aspect or the modified hollow ceramic fibers prepared by the method provided in the second aspect in dry gas desulfurization impurities.

[0047] In the above technical solution, the application includes: raw dry gas is contacted with the modified hollow ceramic fibers to obtain purified dry gas with desulfurized impurities.

[0048] In the above technical scheme, preferably, in the application, a desulfurization refiner is used, in which a multi-layer modified hollow ceramic fiber integrated module is provided, a raw dry gas inlet and an inlet dry gas distributor are provided at the upper end of the desulfurization refiner, the raw dry gas inlet is connected to the inlet dry gas distributor, the inlet dry gas distributor is connected to the modified hollow ceramic fiber module, a dry gas redistributor is provided between adjacent modified hollow ceramic fiber modules, a purified dry gas collecting pipe and a purified dry gas outlet are provided at the lower end of the desulfurization refiner, the purified dry gas collecting pipe is connected to the purified dry gas outlet, the modified hollow ceramic fiber module is connected to the purified dry gas collecting pipe, and each modified hollow ceramic fiber module is provided with a regeneration agent inlet and a regeneration agent outlet. When each modified hollow ceramic fiber module is regenerated, it can be operated in parallel, that is, the regeneration agent is evenly distributed by the regeneration agent distributor and enters each modified hollow ceramic fiber module and then is collected and returned to the regeneration agent storage tank. When each modified hollow ceramic fiber module is regenerated, it can also be operated in series, that is, the regeneration agent enters the bottom modified hollow ceramic fiber module from the top modified hollow ceramic fiber module in turn, and the regeneration agent extracted from the bottom modified hollow ceramic fiber module returns to the regeneration storage tank. The raw dry gas flows in the inner cavity of the modified hollow ceramic fiber, and the regeneration agent flows in the shell side of the modified hollow ceramic fiber module, achieving adsorption and regeneration at the same time, thereby obtaining purified dry gas and working regeneration agent.

[0049] In the above technical scheme, preferably, when the desulfurization refiner is put into use, the raw dry gas enters the fiber cavity of the modified hollow ceramic fiber module through the raw dry gas feed port and the dry gas distributor in turn and flows forward at high speed in the cavity, and the dry gas penetrates and absorbs the inner wall of the modified hollow ceramic fiber membrane, and then the sulfur-containing impurities in the dry gas are selectively adsorbed by the active layer of the inner wall of the fiber membrane. At the same time, the regeneration agent enters the shell side of the modified hollow ceramic fiber module from the regeneration agent inlet. Under the combined action of capillary force, gas-liquid pressure difference and other forces, the regeneration agent uniformly penetrates to the inner side of the fiber wall through the hole channel of the fiber wall. On the one hand, part of the regeneration agent Under the action of dry gas flow, it is further dispersed in the contact layer on the inner surface of the fiber wall and longitudinally penetrates and diffuses to regenerate the activation center of the inner wall of the modified hollow ceramic fiber. On the other hand, part of the regenerant directly reacts with the sulfur-containing impurities in the dry gas. A part of the regenerant after replacement or reaction is exchanged from the wall micropores to the main phase of the regenerant outside the hollow ceramic fiber, and a part of it is entrained out of the hollow ceramic fiber by the dry gas and then collected by the hollow ceramic fiber outlet liquid collector, and then produced from the hollow ceramic fiber dry gas entrainment liquid production outlet, mixed with the regenerant produced from the shell side of the hollow ceramic fiber module, and returned to the regenerant storage tank.

[0050] In the above technical solution, the modified hollow ceramic fibers are distributed in the modified hollow ceramic fiber module to form a basic contact unit for removing sulfur-containing impurities. It is a multiphase contact unit integrating adsorption and regeneration, and adopts on-line in-situ real-time continuous adsorption and regeneration, that is, adsorption and in-situ regeneration occur simultaneously on the inner wall of the modified hollow ceramic fiber. The regenerant uniformly penetrating through the micropores on the inner wall of the modified hollow ceramic fiber realizes the regeneration of the adsorption center through mass transfer by contacting the saturated adsorption center.

[0051] In the above technical solution, the regenerant is selected from at least one of diethanolamine, N-methyldiethanolamine, and potassium carbonate. Preferably, in terms of the mass composition percentage of the regenerant solution, N-methyldiethanolamine is 20% - 40%, diethanolamine is 3% - 5%, potassium carbonate is 3% - 5%, and the rest is demineralized water. The regeneration conditions are as follows: the temperature is 20 - 50°C, the pressure difference relative to the raw dry gas (the difference between the pressure of the regenerant liquid and the pressure of the raw dry gas) is (-100) - (-50) kPa, and the feed volume ratio of the dry gas raw material to the regenerant solution is 400 - 600 by volume.

[0052] In the above technical solution, the volumetric space velocity of the raw dry gas feed is 500 - 1000 h -1 , and the modified hollow ceramic fibers are packed in a regular module. The cross-sectional arrangement density of the modified hollow ceramic fibers is 30000 - 80000 pieces / m 2 . The operating conditions for desulfurization are as follows: the adsorption temperature is 20 - 50°C, and the adsorption pressure (gauge pressure) is 500 - 1200 kPa.

[0053] In the above technical solution, the raw dry gas comes from refinery catalytic cracking, thermal cracking, delayed coking, and hydrocracking. The raw dry gas includes, but is not limited to, ethylene, methane, ethane, propane, propylene, isobutane, n-butane, trans-butene, n-butene, isobutene, cis-butene, oxygen, nitrogen, hydrogen, carbon monoxide, carbon dioxide, acetylene, 1,3-butadiene, alkanes or alkenes with more than five carbons, and sulfur-containing impurities. The sulfur-containing impurities include, but are not limited to, at least one of hydrogen sulfide, carbonyl sulfide, and carbon disulfide, which come from sulfur-containing impurities in crude oil and sulfur-containing components generated during its refining process. In the raw dry gas, the volume content of ethylene is 5% - 40%, preferably 10% - 20%. In the impurities, the volume content based on the total sulfur element is not less than 500 ppm, preferably not less than 50000 ppm, more preferably not less than 100000 ppm, and the volume content based on the total sulfur element is not higher than 150000 ppm.

[0054] In the above technical solution, before the raw material dry gas is desulfurized, through the step of removing solid dust, methods such as degumming powder tower and filtration can be adopted. The degumming powder tower is a conventional packing tower and / or plate tower in the art, with the number of theoretical plates being 1 - 5, the operating temperature being 20 - 50 °C, the degumming powder being fresh water and / or desalted water, and the gas-water volume ratio being 40 - 60. The filtration can adopt conventional bag type, and / or basket type, and / or filter element type filters in the art, with the separation accuracy being 3 - 5 microns.

[0055] In the above technical solution, the purified dry gas after desulfurization is further subjected to a liquid separation step, such as a cyclone liquid separation method. The cyclone is a conventional liquid separation device in the art, with the separation accuracy being 100 - 300 microns.

[0056] In the above technical solution, the purified dry gas after desulfurization is further washed with water. Among them, the operating conditions of the water washing tower are as follows: the temperature is 20 - 50 °C, the pressure is, in gauge pressure, 500 - 1200 kPa, the water is fresh water and / or desalted water, and the number of theoretical plates of the water washing tower is 6 - 10. The volume ratio of the desulfurized and purified dry gas to water is 50 - 80 by volume.

[0057] In the above technical solution, according to the requirement for the propylene content in the product dry gas, the purified dry gas with desulfurized impurities can be contacted with a depropylene agent to obtain purified dry gas with propylene removed. Among them, the depropylene agent is a conventional depropylene agent in the art, preferably at least one of benzene and diethylbenzene. The conditions for the contact between the dry gas and the depropylene agent are as follows: the temperature is 10 - 25 °C, the pressure is, in gauge pressure, 700 - 1500 kPa, the number of theoretical plates of the depropylene contact tower is 8 - 15. The volume ratio of the dry gas to the depropylene agent is 60 - 90 by volume.

[0058] In the above technical solution, preferably, the total sulfur volume content in the obtained purified dry gas is not higher than 10 ppm, preferably not higher than 5 ppm, and more preferably not higher than 3 ppm.

[0059] In the above technical solution, preferably, the obtained purified dry gas can meet the requirements for the long-term operation of the ethylbenzene alkylation catalyst.

[0060] The fourth aspect of the present invention provides a separation system for removing impurities in dry gas, including:

[0061] 1) A desulfurization and refining device for removing sulfur-containing impurities in the dry gas raw material;

[0062] 2) A water washing tower for removing nitrogen-containing impurities in the desulfurized and purified dry gas;

[0063] 3) A depropylene contact tower for removing propylene in the water-washed and purified dry gas.

[0064] In the above technical solution, a degumming powder tower is provided before the desulfurization and refining unit to remove solid gum powder in the dry gas raw material.

[0065] In the above technical solution, a cyclone separator is arranged between the outlet of the desulfurization and refining unit and the inlet of the water washing tower to remove the trace alkaline liquid droplets entrained in the dry gas at the outlet of the desulfurization and refining unit.

[0066] In the above technical solution, the desulfurization and refining unit is provided with a regenerant inlet and a regenerant outlet for introducing and discharging the regenerant into and out of the desulfurization and refining unit.

[0067] In the above technical solution, a regenerant storage tank is provided to cache the regenerant, including recycled regenerant and fresh regenerant.

[0068] In the above technical solution, a high-pressure pump is provided for pressurized transportation of the regenerant.

[0069] Compared with the prior art, the present invention has the following advantages:

[0070] 1. The inventors of the present invention have found through research that there are sulfur-containing impurities in the dry gas raw material that have a significant impact on the ethylbenzene alkylation catalyst, and these impurities will continuously accumulate in the catalyst, resulting in a decrease in the activity of the ethylbenzene catalyst and a shortening of the operation cycle. Due to the increasing proportion of sulfur-containing crude oil refining and the volatility and limitations of existing conventional desulfurization processes, the sulfur-containing impurities in the dry gas raw material continue to fluctuate significantly. If only fixed-bed adsorption is carried out using conventional adsorbents (such as ion exchange resins, activated carbon, etc.), the adsorbent is easily saturated, conventional regeneration operations are frequent, and the wastewater discharge is large. The inventors have further found that by using the highly active groups on the modified hollow ceramic fibers to efficiently adsorb the sulfur-containing impurities in the raw material dry gas, and then using a regenerant with low corrosion but a desorption function preferably to penetrate from the outside of the modified hollow ceramic fibers into the inside of the ceramic fibers, and carry out molecular exchange and transfer with the sulfur-containing impurities adsorbed on the active groups, so that the adsorbed impurity molecules are transferred from the inner wall of the ceramic fibers to the outer wall and the main body of the regenerant solution under the driving force of the concentration difference, solving the problem that it is difficult to continuously regenerate the adsorbent in-situ online. At the same time, since the regenerant is used to continuously regenerate the active centers, there are sufficient fresh active centers for continuous adsorption, solving the problem of low operation flexibility of conventional rectification desulfurization. In addition, by using the relative uniformity of the pores on the wall of the modified hollow ceramic fiber membrane, the regeneration of the active centers is more uniform, improving the removal effect of the active centers on sulfur-containing impurities.

[0071] 2. During the modification process of the hollow ceramic fibers in the present invention, a silanized layer is first formed on the inner surface of the hollow ceramic fibers, and then the first modification treatment is carried out, so that the original function of the hollow ceramic fibers can be fully exerted. Then, through the second modification treatment, a modified layer with adsorption active centers having appropriate adsorption strength can be formed on the surface of the silanized layer. During continuous adsorption and regeneration operations, good adsorption and regeneration effects can be achieved. Preferably, by subjecting the hollow ceramic fibers to the third modification treatment, the gas film resistance during the contact between the dry gas and the modified layer formed by the second modification treatment can be reduced, and the mass transfer rate can be increased. The modified layer formed by the third modification treatment has a certain absorption effect on each component in the dry gas, forming a dry gas concentration zone with a certain thickness. This concentration zone is in dynamic equilibrium with the main body zone of the dry gas, and the sulfur impurity components are continuously exchanged to the modified layer formed by the second modification treatment, thereby achieving deep removal of sulfur impurities in the dry gas. At the same time, preferably, the regenerant of the present invention has good permeability, especially capable of effectively desorbing the sulfur impurities adsorbed in the modified layer formed by the second modification treatment to restore the active centers of the modified hollow ceramic fibers, so as to achieve a good balance between continuous adsorption and regeneration.

[0072] 3. The present invention solves the problems of high content of trace sulfur impurities in the existing dry gas raw materials that affect the ethylbenzene alkylation catalyst and short operation cycle of the alkylation catalyst. By efficiently and continuously adsorbing the sulfur impurities in the dry gas raw materials, the operation cycle of the alkylation catalyst is greatly improved, and the production cost of ethylbenzene is reduced. BRIEF DESCRIPTION OF THE DRAWINGS

[0073] Figure 1 It is a schematic diagram of a separation system for efficiently removing impurities in dry gas according to the present invention;

[0074] Among them, the descriptions of the reference numerals are as follows:

[0075] 0101 is a water washing tower, 0102 is a depropylene contact tower, 2101 is a degumming powder tower, 2102 is a dry gas filter, 2103 is a desulfurization refiner, 2104 is a regenerant storage tank, 2105 is a regenerant feed pump, 2106 is a cyclone separator, 0201 is a raw material dry gas inlet, 0202 is a water washing liquid inlet of the water washing tower, 0203 is a water washing rich liquid outlet of the water washing tower, 0204 is a depropylene agent inlet of the depropylene contact tower, 0205 is a dry gas outlet at the top of the depropylene contact tower, 0206 is a depropylene agent rich liquid outlet of the depropylene contact tower, 2201 is a degumming powder liquid inlet, 2202 is a rich degumming powder liquid outlet, 2203 is a dry gas filter interception outlet, 2204 is a desulfurization refiner inlet, 2205 is a desulfurization refiner outlet, 2206 is a regenerant inlet of the desulfurization refiner, 2207 is a regenerant outlet of the desulfurization refiner, 2208 is a fresh regenerant or regenerant lean liquid inlet, 2209 is a regenerant rich liquid outlet, 2210 is a balance pipeline interface, 2211 is a dry gas inlet of the cyclone separator, 2212 is a condensate outlet of the cyclone separator;

[0076] Figure 2 Schematic diagram of gas-liquid flow in the hollow ceramic fiber of the present invention;

[0077] Among them, the reference numerals are explained as follows:

[0078] 2109 is the dry gas inlet of the module raw material, 2110 is the regenerant inlet, 2111 is the end seal plate of the hollow ceramic fiber, 2112 is the wall of the hollow ceramic fiber membrane, 2113 is the pore channel of the hollow ceramic fiber membrane wall, 2114 is the dry gas outlet of the module raw material, 2115 is the inner wall of the hollow ceramic fiber membrane, 2116 is the regenerant outlet, 2117 is the inlet distributor of the hollow ceramic fiber, 2118 is the outlet collector of the hollow ceramic fiber, and 2119 is the dry gas entrained liquid extraction outlet of the hollow ceramic fiber. Detailed implementation manners

[0079] Next, the technical solutions in the embodiments of the present invention will be described clearly and completely. Obviously, the described embodiments are only a part of the embodiments of the present invention, rather than all of the embodiments. All other embodiments obtained by those skilled in the art based on the embodiments of the present invention without making creative efforts belong to the protection scope of the present invention.

[0080] In the present invention, the inner surface of the hollow ceramic fiber includes a silane layer, a first modified layer, and a second modified layer from the outside to the inside, which means that the silane layer is on the inner surface of the hollow ceramic fiber, the first modified layer is on the inner surface of the silane layer, and the second modified layer is on the inner surface of the first modified layer.

[0081] In the present invention, the inner surface of the hollow ceramic fiber includes a silane layer, a first modified layer, a second modified layer, and a third modified layer from the outside to the inside, which means that the silane layer is on the inner surface of the hollow ceramic fiber, the first modified layer is on the inner surface of the silane layer, the second modified layer is on the inner surface of the first modified layer, and the third modified layer is on the inner surface of the second modified layer.

[0082] In the present invention, the analysis of low-carbon hydrocarbon components is carried out using a gas chromatograph Agilent 7890A GC (Agilent, USA), equipped with an HP-PLOT Al2O3 KCl (50m×0.53mm×15μm) capillary chromatographic column. The column temperature is maintained at 100°C for 10 minutes, and then increased to 120°C at a rate of 30°C per minute and maintained for 3 minutes. The carrier gas He flow rate is 3 mL / min, the injection volume is 0.1 mL (quantitative loop), the split ratio is 5:1, the injection port temperature is 250°C, and the detector (FID) temperature is 250°C.

[0083] In the present invention, the sulfur element content in the dry gas material is tested using a Mitsubishi sulfur and nitrogen analyzer NSX-2100V. The analysis method is as follows: the argon flow rate is 200 ml / minute, the oxygen flow rate is 400 ml / minute, and the combustion temperature is 1000-1050 °C.

[0084] A separation system for efficiently removing impurities from dry gas according to the present invention (such as Figure 1As shown in the figure, it includes: 0101 is a water washing tower, 0102 is a depropylene contact tower, 2101 is a degumming powder tower, 2102 is a dry gas filter, 2103 is a desulfurization and refining device, 2104 is a regenerant storage tank, 2105 is a regenerant feed pump, 2106 is a cyclone separator; 0201 is a raw material dry gas inlet, 0202 is a water washing liquid inlet of the water washing tower, 0203 is a water washing rich liquid outlet of the water washing tower, 0204 is a depropylene agent inlet of the depropylene contact tower, 0205 is a dry gas outlet at the top of the depropylene contact tower, 0206 is a depropylene agent rich liquid outlet of the depropylene contact tower, 2201 is a degumming powder liquid inlet, 2202 is a rich degumming powder liquid outlet, 2203 is a dry gas filter retention outlet, 2204 is a desulfurization and refining device inlet, 2205 is a desulfurization and refining device outlet, 2206 is a regenerant inlet of the desulfurization and refining device, 2207 is a regenerant outlet of the desulfurization and refining device, 2208 is a fresh regenerant or regenerant lean liquid inlet, 2209 is a regenerant rich liquid outlet, 2210 is a balance pipeline interface, 2211 is a dry gas inlet of the cyclone separator, 2212 is a condensate outlet of the cyclone separator. The separation process is as follows: Dry gas raw materials (such as from refinery catalytic cracking, thermal cracking, delayed coking, hydrocracking) enter the degumming powder tower 2101 through the raw material dry gas inlet 0201, contact with the liquid coming in from the degumming powder liquid inlet 2201, separate and remove solid gum powder in the dry gas raw materials, and the liquid after degumming powder is discharged from the rich degumming powder liquid outlet 2202. The gas phase at the top of the degumming powder tower 2101 enters the dry gas filter 2102 to further remove residual gum powder and free liquid in the dry gas raw materials, and then enters the desulfurization and refining device 2103 from the desulfurization and refining device inlet 2204. After being distributed by the dry gas distributor, it enters the inner cavity of the modified hollow ceramic fiber. Sulfur-containing impurities in the dry gas raw materials are adsorbed by the active groups on the inner surface of the modified hollow ceramic fiber. At the same time, the regenerant in the regenerant storage tank 2104 is transported to the shell side of the modified hollow ceramic fiber module of the desulfurization and refining device 2103 through the regenerant feed pump 2105. Under the action of a certain liquid pressure, dry gas pressure and capillary force of the modified hollow ceramic fiber pores, it penetrates to the inner surface of the fiber to realize the regeneration of the adsorption surface. The dry gas at the outlet of the desulfurization and refining device 2103 enters the cyclone separator 2106 to remove trace alkaline liquid droplets entrained in the dry gas at the outlet of the desulfurization and refining device, and then enters the water washing tower 0101 to remove possible trace nitrogen-containing impurities in the desulfurized and purified dry gas. Then, it enters the depropylene contact tower 0102 through a conventional pressurization device or directly to counter-currently contact with the depropylene agent entering from the depropylene agent inlet 0204 of the depropylene contact tower to remove propylene in the dry gas. The depropylene-purified dry gas is discharged through the dry gas outlet 0205 at the top of the depropylene contact tower, and the depropylene agent rich liquid is discharged through the depropylene agent rich liquid outlet 0206 of the depropylene contact tower.

[0085] Schematic diagram of gas-liquid flow of the modified hollow ceramic fiber of the present invention (as Figure 2As shown in the figure, it includes: 2109 is the inlet of the module raw material dry gas, 2110 is the inlet of the regenerant, 2111 is the hollow ceramic fiber end sealing plate, 2112 is the hollow ceramic fiber membrane wall, 2113 is the hollow ceramic fiber membrane wall pore channel, 2114 is the outlet of the module raw material dry gas, 2115 is the inner wall of the hollow ceramic fiber membrane, 2116 is the outlet of the regenerant, 2117 is the hollow ceramic fiber inlet distributor, 2118 is the hollow ceramic fiber outlet liquid collector, and 2119 is the outlet for collecting the dry gas entrained liquid of the hollow ceramic fiber. The gas-liquid flow process is as follows: The desulfurized and pretreated dry gas entering from the module raw material dry gas inlet 2109 is distributed by the hollow ceramic fiber inlet distributor 2117 and then enters the fiber inner cavity formed by the enclosure of the hollow ceramic fiber membrane wall 2112, contacts the active adsorption centers on the inner wall 2115, and the adsorbed dry gas is discharged through the module raw material dry gas outlet 2114 to the hollow ceramic fiber outlet liquid collector 2118. After separating the free liquid, it enters the next-level module for further adsorption. The regenerant enters the cavity with hollow ceramic fiber end sealing plates 2111 at both ends from the regenerant inlet 2110, and under the action of liquid pressure, dry gas pressure, and capillary force, it penetrates from the outer wall of the hollow ceramic fiber to the inner wall to regenerate the adsorption centers on the inner wall.

[0086]

Example 1

[0087] In this example, the dry gas raw material comes from the catalytic cracking in a refinery. By volume, the dry gas composition includes: methane 16.3840%, ethane 9.1091%, ethylene 16.9379%, hydrogen sulfide 6.4433%, propane 0.1937%, propylene 0.9112%, isobutane 0.0901%, n-butane 0.0145%, trans-butene 0.0057%, cis-butene 0.0001%, oxygen 0.1468%, nitrogen 14.3707%, carbonyl sulfide 0.0958%, n-butene 0.0177%, isobutene 0.0376%, carbon disulfide 0.0104%, hydrogen 28.6812%, carbon monoxide 1.5062%, carbon dioxide 2.9757%, acetylene 0.0049%, 1,3-butadiene 0.0001%, alkanes or alkenes with five or more carbon atoms 1.2428%, and other components 0.8204%. The volume content of sulfur-containing impurities in terms of total sulfur element is 67000 ppm.

[0088] The separation process in this example is the same as that in Figure 1 As shown in the figure, the schematic diagram of the gas-liquid flow of the hollow ceramic fiber is shown in Figure 2 .

[0089] The desulfurization refiner is filled with modified hollow ceramic fibers. The dry gas raw material flows through the inner cavity of the modified hollow ceramic fibers, and the sulfur-containing impurities are adsorbed by the adsorption active centers in the fiber inner cavity. The regenerant solution penetrates to the fiber inner wall under the action of liquid pressure and the capillary force of the ceramic membrane pores to regenerate the saturated active centers of the adsorption.

[0090] Preparation method of modified hollow ceramic fiber, comprising: first treating the hollow ceramic fiber with a silane reagent to obtain a silanized hollow ceramic fiber, and then successively performing a first modification treatment, a first post-modification treatment, a second modification treatment, a third modification treatment, a third post-modification treatment, an activation treatment, and a demineralized water treatment to obtain the modified hollow ceramic fiber. The inner diameter of the hollow ceramic fiber is 0.6 mm, the outer diameter is 1.3 mm, the average pore diameter of the fiber membrane wall is 750 nm, the porosity is 60%, and the material is silica. Among them, the preparation of the hollow ceramic fiber is as follows: Polyethersulfone (molecular weight of 45,000), N-methylpyrrolidone, silica, and polyvinylpyrrolidone K90 are formulated into a raw material solution according to a mass ratio of 15:130:200:2, stirred at 75°C for 30 hours, and then left to stand and defoam for 8 hours to obtain a casting solution. The inner and outer coagulation baths of the spinneret are deionized water at 2°C. The inner diameter of the spinneret is 0.6 mm, the outer diameter is 1.3 mm, the flow rate of the casting solution is 8.5 ml / min, the pressure of the casting solution inside the spinneret is 200 kPa (gauge pressure), the ambient temperature is 25°C, the ambient humidity is 60%, and the casting solution exchanges solvents with the inner and outer coagulation baths and phase-separates and cures to form a hollow fiber blank. After the hollow fiber blank is washed 6 times with demineralized water, it is air-dried at 25°C, and then heated from 0.7°C / min to 1700°C and held at a constant temperature for 4.5 hours, and then naturally cooled to 25°C to obtain the hollow ceramic fiber. The silanization treatment of the hollow ceramic fiber is as follows: The hollow ceramic fiber is subjected to a flow treatment in a silane reagent (γ-methacryloxypropylmethyldiethoxysilane) solution, and then dried and cured to obtain a silanized hollow ceramic fiber with a molar ratio of siloxyl group to silicon-carbon group of 0.8 and a thickness of 20 μm of a silane film. The silanization treatment conditions are as follows: The composition of the silane reagent solution, by volume fraction, is silane reagent: demineralized water: absolute ethanol = 6:14:85, the pH value is 8.0, and the pre-hydrolysis time is 30 hours. The hollow ceramic fiber is first passed through petroleum ether with a boiling point of 80-90°C at an inner surface fluid linear velocity of 0.15 m / s for continuous replacement for 2.5 hours, and then passed through the silane reagent solution at an inner surface fluid linear velocity of 0.3 m / s for a feeding time of 3 minutes. The drying and curing temperature is 120°C, the drying time is 40 minutes, and the drying atmosphere is nitrogen. The replacement, drying, and continuous treatment of petroleum ether and silane reagent solution are carried out 4 times.

[0091] The first modifier in this embodiment is 1-(3-buten-1-yl)-2,4-dichlorobenzene, benzoyl peroxide and toluene. By mass, 1-(3-buten-1-yl)-2,4-dichlorobenzene: benzoyl peroxide: toluene = 20:2:150. The treatment conditions for the first modifier are as follows: control the fluid linear velocity of the first modifier on the inner surface of the silylated hollow ceramic fiber membrane to be 0.6 m / s, the treatment temperature to be 45 °C, and the treatment time to be 3 hours. The phenyl content introduced into the modified hollow ceramic fiber after treatment with the first modifier is 0.21 mol / m 2 , and the thickness is 4.5 microns. After modifying the hollow ceramic fiber with the first modifier, a first modified silylated hollow ceramic fiber intermediate is obtained.

[0092] The first modified silylated hollow ceramic fiber intermediate is subjected to a second modification treatment after the first post-treatment to obtain a second modified silylated hollow ceramic fiber intermediate. The post-treatment agent used for the first post-treatment is absolute ethanol. The conditions for the first post-treatment are as follows: liquid ethanol is transported to the inner cavity of the hollow ceramic fiber through a conventional pump, the temperature is 70 °C, the linear velocity is 0.5 m / s, the continuous treatment time is 2 hours, and after the ethanol treatment, it is purged and dried with nitrogen at 120 °C for 0.7 hours. The second modifier is N,N-bis(4-aminophenyl)-1,4-phenylenediamine, polyoxyethylene polyoxypropylene ether (average molecular weight of 2650), zinc chloride and toluene. By mass, N,N-bis(4-aminophenyl)-1,4-phenylenediamine: polyoxyethylene polyoxypropylene ether: zinc chloride: toluene = 25:4:15:250. The zinc chloride used is anhydrous zinc chloride. The treatment conditions for the second modifier are as follows: control the fluid linear velocity of the second modifier on the inner surface of the silylated hollow ceramic fiber to be 1.0 m / s, the treatment temperature to be 65 °C, the treatment time to be 3 hours, and the treatment pressure (gauge pressure) to be 450 kPa. The content of secondary amino groups introduced into the modified hollow ceramic fiber after treatment with the second modifier is 0.40 mol / m 2 , the content of primary amino groups is 0.15 mol / m 2 , and the content of tertiary amino groups is 0.10 mol / m 2 .

[0093] The second modified silanized hollow ceramic fiber intermediate is subjected to a third modification treatment to obtain a third modified silanized hollow ceramic fiber intermediate. The third modifier is N-amidino-2-(2,6-dichlorophenyl)acetamide, tetrahydrofuran, 3,5-dichloro-2-methoxyaniline, and zinc chloride. By mass fraction, N-amidino-2-(2,6-dichlorophenyl)acetamide:tetrahydrofuran:3,5-dichloro-2-methoxyaniline:zinc chloride = 15:250:60:15. The treatment conditions for the third modifier are as follows: controlling the fluid linear velocity of the third modifier on the inner surface of the silanized hollow ceramic fiber to be 2.3 m / s, the treatment temperature to be 68 °C, the treatment time to be 7 hours, and the treatment pressure (gauge pressure) to be 400 kPa. After being treated with the third modifier, the content of secondary amino groups introduced into the modified hollow ceramic fiber is 18 mmol / m 2 , and the content of imino groups is 8.1 mmol / m 2 , and the content of methoxy groups is 24.3 mmol / m 2 .

[0094] The third modified silanized hollow ceramic fiber intermediate is subjected to a post-treatment of the third modification to obtain a pre-activated modified silanized hollow ceramic fiber intermediate. The pre-activator used for the post-treatment of the third modification is anhydrous ethanol. The post-treatment conditions of the third modification are as follows: liquid ethanol is transported to the inner cavity of the hollow ceramic fiber by a conventional pump, the temperature is 70 °C, the linear velocity is 0.5 m / s, the continuous treatment time is 2 hours, and after the ethanol treatment, it is purged and dried with nitrogen at 120 °C for 0.7 hours.

[0095] The pre-activated modified silanized hollow ceramic fiber intermediate is subjected to an activation treatment and a desalted water treatment to obtain a modified hollow ceramic fiber. The activator is a 5% (mass concentration) aqueous sodium hydroxide solution. The treatment conditions for the activator treatment are as follows: the aqueous sodium hydroxide solution is transported to the inner cavity of the hollow ceramic fiber by a conventional pump, the treatment temperature is 40 °C, the linear velocity is 0.2 m / s, the treatment time is 2.5 hours, and then desalted water is transported to the inner cavity of the hollow ceramic fiber by a conventional pump, the linear velocity is 0.2 m / s, and the treatment temperature is 50 °C.

[0096] In this embodiment, the dry gas feed volume space velocity is 750 h -1 , and the cross-sectional arrangement density of the ceramic fibers of the hollow ceramic fiber regular module is 60,000 roots / m 2。The adsorption temperature when the dry gas passes through the inner cavity of the ceramic fiber is 35°C, and the adsorption pressure (gauge pressure) is 850 kPa. The regenerant includes diethanolamine, N-methyldiethanolamine, potassium carbonate, and demineralized water. In terms of the mass composition percentage of the regenerant solution, N-methyldiethanolamine is 30%, diethanolamine is 4%, potassium carbonate is 4%, and the rest is demineralized water. The regeneration conditions are as follows: the temperature is 35°C, the pressure difference relative to the raw dry gas (the difference between the regenerant liquid pressure and the raw dry gas pressure) is -75 kPa, and the feed ratio of the dry gas raw material to the regenerant solution is 500 by volume.

[0097] The degumming powder tower in this embodiment is a conventional packed tower with 3 theoretical plates, an operating temperature of 35°C, the degumming powder is fresh water, and the gas-water ratio is 50. The dry gas filter is a conventional bag filter with a separation accuracy of 4 microns.

[0098] The cyclone in this embodiment is a conventional liquid separation device in the art with a separation accuracy of 200 microns.

[0099] The operating conditions of the desulfurized and purified dry gas in the water wash tower are as follows: the temperature is 35°C, the pressure is 850 kPa by gauge pressure, the water is demineralized water, and the water wash tower has 8 theoretical plates. The usage ratio of the desulfurized and purified dry gas to the demineralized water is 65 by volume.

[0100] The depropylenating agent is benzene. The conditions for the contact between the raw dry gas and the depropylenating agent are as follows: the temperature is 17°C, the pressure is 1100 kPa by gauge pressure, the depropylenating contact tower has 12 theoretical plates. The usage ratio of the raw dry gas to the depropylenating agent is 75 by volume.

[0101] The total sulfur volume content in the depropylenated and purified dry gas obtained in this embodiment is 4.5 ppm.

[0102]

Example 2

[0103] The dry gas raw material described in this embodiment is the same as that in Example 1. The separation process in this embodiment is the same as that in Example 1.

[0104] The desulfurization refiner is filled with modified hollow ceramic fibers. The dry gas raw material flows through the inner cavity of the modified hollow ceramic fibers, and the sulfur-containing impurities are adsorbed by the adsorption active centers coated on the inner wall of the modified hollow ceramic fiber cavity. The regenerant solution penetrates to the inner wall of the fiber under the action of the liquid pressure and the capillary force of the ceramic membrane pores to regenerate the saturated active centers adsorbed.

[0105] Preparation method of modified hollow ceramic fiber, comprising: first treating the hollow ceramic fiber with a silane reagent to obtain a silanized hollow ceramic fiber, and then successively performing a first modification treatment, a first post-modification treatment, a second modification treatment, a third modification treatment, a third post-modification treatment, an activation treatment and a demineralized water treatment to obtain the modified hollow ceramic fiber. The inner diameter of the hollow ceramic fiber is 0.4 mm, the outer diameter is 1.4 mm, the average pore diameter of the fiber membrane wall is 550 nm, the porosity is 67%, and the material is silica. The preparation of the hollow ceramic fiber membrane is as follows: Polyethersulfone (molecular weight of 45000), N-methylpyrrolidone, silica, polyvinylpyrrolidone K90 are formulated into a raw material solution according to a mass ratio of 18:110:160:2.5, stirred at 65 °C for 25 hours, and then left to stand for defoaming for 7 hours to obtain a casting solution. The inner and outer coagulation baths of the spinneret are deionized water at 0.5 °C, the inner diameter of the spinneret is 0.4 mm, the outer diameter is 1.4 mm, the flow rate of the casting solution is 7.5 ml / min, the pressure of the casting solution inside the spinneret is 150 kPa (gauge pressure), the ambient temperature is 22 °C, the ambient humidity is 55%, and solvent exchange and phase separation curing occur between the casting solution and the inner and outer coagulation baths to form a hollow fiber blank. After the hollow fiber blank is washed 5 times with demineralized water, it is dried with air at 22 °C, then heated from 22 °C to 1650 °C at a rate of 0.6 °C / min, held at a constant temperature for 4.0 hours, and then naturally cooled to 22 °C to obtain the hollow ceramic fiber. The silanization treatment of the hollow ceramic fiber is to perform a flow treatment on the hollow ceramic fiber in a silane reagent (γ-methacryloxypropylmethyldiethoxysilane) solution, and then dry and cure it to obtain a silanized hollow ceramic fiber with a silane film having a molar ratio of siloxy group to silicon-carbon group of 0.9 and a thickness of 26 μm. Among them, the silanization treatment conditions are as follows: The composition of the silane reagent solution, by volume fraction, is silane reagent: demineralized water: absolute ethanol = 7:15:88, the pH value is 8.3, and the pre-hydrolysis time is 35 hours. The hollow ceramic fiber is first passed through petroleum ether with a boiling point of 80-90 °C at an inner surface fluid linear velocity of 0.1 m / s for continuous replacement for 2.8 hours, and then passed through the silane reagent solution at an inner surface fluid linear velocity of 0.22 m / s for a feeding time of 2 minutes. The drying and curing temperature is 125 °C, the drying time is 45 minutes, and the drying atmosphere is nitrogen. The replacement drying of petroleum ether and silane reagent solution is continuously processed 5 times.

[0106] The first modifier described in this embodiment is 1-(3-buten-1-yl)-2,4-dichlorobenzene, benzoyl peroxide and toluene. By mass, 1-(3-buten-1-yl)-2,4-dichlorobenzene: benzoyl peroxide: toluene = 24:2.5:110. The treatment conditions for the treatment with the first modifier are as follows: control the fluid linear velocity of the first modifier on the inner surface of the silylated hollow ceramic fiber membrane to be 0.43 m / s, the treatment temperature to be 55 °C, and the treatment time to be 3.5 hours. The phenyl content introduced into the modified hollow ceramic fiber after treatment with the first modifier is 0.27 mol / m 2 , and the thickness is 5 microns. After treating the ceramic fiber with the modifier, a first modified silylated hollow ceramic fiber intermediate is obtained.

[0107] The first modified silylated hollow ceramic fiber intermediate is subjected to a second modification treatment after the first post-treatment to obtain a second modified silylated hollow ceramic fiber intermediate. The post-treatment agent used for the first post-treatment is anhydrous ethanol. The first post-treatment conditions are as follows: liquid ethanol is pumped into the inner cavity of the hollow ceramic fiber through a conventional pump, the temperature is 75 °C, the linear velocity is 0.4 m / s, the continuous treatment time is 2.5 hours, and after the ethanol treatment, it is purged and dried with nitrogen at 125 °C for 0.9 hours. The second modifier is N,N-bis(4-aminophenyl)-1,4-phenylenediamine, polyoxyethylene polyoxypropylene ether (average molecular weight 3000), zinc chloride and toluene. By mass, N,N-bis(4-aminophenyl)-1,4-phenylenediamine: polyoxyethylene polyoxypropylene ether: zinc chloride: toluene = 28:5:18:220. The zinc chloride used is anhydrous zinc chloride. The treatment conditions for the treatment with the second modifier are as follows: control the fluid linear velocity of the second modifier on the inner surface of the silylated hollow ceramic fiber to be 0.7 m / s, the treatment temperature to be 70 °C, the treatment time to be 3.5 hours, and the treatment pressure (gauge pressure) to be 350 kPa. The content of secondary amino groups introduced into the modified hollow ceramic fiber after treatment with the second modifier is 0.48 mol / m 2 , the content of primary amino groups is 0.21 mol / m 2 , and the content of tertiary amino groups is 0.13 mol / m 2 .

[0108] The second modified silanized hollow ceramic fiber intermediate is subjected to a third modification treatment to obtain a third modified silanized hollow ceramic fiber intermediate. The third modifier is N-amidino-2-(2,6-dichlorophenyl)acetamide, tetrahydrofuran, 3,5-dichloro-2-methoxyaniline, and zinc chloride. By mass parts, N-amidino-2-(2,6-dichlorophenyl)acetamide:tetrahydrofuran:3,5-dichloro-2-methoxyaniline:zinc chloride = 18:210:70:18. The treatment conditions for the third modifier treatment are as follows: controlling the fluid linear velocity of the third modifier on the inner surface of the silanized hollow ceramic fiber to be 2.7 m / s, the treatment temperature to be 73 °C, the treatment time to be 7.5 hours, and the treatment pressure (gauge pressure) to be 350 kPa. The content of secondary amino groups introduced into the modified hollow ceramic fiber after the third modifier treatment is 28 mmol / m 2 , and the content of imino groups is 12.5 mmol / m 2 , and the content of methoxy groups is 37 mmol / m 2 .

[0109] The third modified silanized hollow ceramic fiber intermediate is subjected to a third post-modification treatment to obtain a pre-activated modified silanized hollow ceramic fiber intermediate. The pre-activator used in the third post-modification treatment is anhydrous ethanol. The third post-modification treatment conditions are as follows: liquid ethanol is transported to the inner cavity of the hollow ceramic fiber by a conventional pump, the temperature is 75 °C, the linear velocity is 0.4 m / s, the continuous treatment time is 2.5 hours, and after the ethanol treatment, it is purged and dried with nitrogen at 125 °C for 0.9 hours.

[0110] The pre-activated modified silanized hollow ceramic fiber intermediate is subjected to an activation treatment and a desalted water treatment to obtain a modified hollow ceramic fiber. The activator is a 5.5% (mass concentration) aqueous sodium hydroxide solution. The treatment conditions for the activator treatment are as follows: the aqueous sodium hydroxide solution is transported to the inner cavity of the hollow ceramic fiber by a conventional pump, the treatment temperature is 45 °C, the fluid linear velocity is 0.26 m / s, the treatment time is 2.8 hours, and then desalted water is transported to the inner cavity of the hollow ceramic fiber by a conventional pump, the fluid linear velocity is 0.27 m / s, and the treatment temperature is 55 °C.

[0111] In this example, the dry gas feed volume space velocity is 600 h -1 , and the cross-sectional arrangement density of the ceramic fibers of the hollow ceramic fiber regular module is 70000 roots / m 2。When the dry gas passes through the inner cavity of the ceramic fiber, the adsorption temperature is 45 °C and the adsorption pressure (gauge pressure) is 1100 kPa. The regenerant includes those selected from diethanolamine, N-methyldiethanolamine, potassium carbonate, and desalted water. In terms of the mass composition percentage of the regenerant solution, N-methyldiethanolamine is 35%, diethanolamine is 4.5%, potassium carbonate is 4.5%, and the rest is desalted water. The regeneration conditions are as follows: the temperature is 45 °C, the pressure difference relative to the raw material dry gas (the difference between the regenerant liquid pressure and the raw material dry gas pressure) is -60 kPa, and the volume ratio of the dry gas raw material to the regenerant is 450.

[0112] The degumming powder tower in this example is a conventional packed tower with 4 theoretical plates, an operating temperature of 45 °C, fresh water as the degumming powder, and a gas-water ratio of 44. The dry gas filter is a conventional bag filter with a separation accuracy of 4 microns.

[0113] The cyclone separator in this example is a conventional liquid separation device in the art with a separation accuracy of 200 microns.

[0114] The operating conditions of the desulfurized and purified dry gas in the water wash tower are as follows: the temperature is 25 °C, the pressure is 1100 kPa (gauge pressure), the water is desalted water, and the water wash tower has 9 theoretical plates. The volume ratio of the desulfurized and purified dry gas to the desalted water is 55.

[0115] The depropylenating agent is benzene. The conditions for the contact between the raw material dry gas and the depropylenating agent are as follows: the temperature is 12 °C, the pressure is 1400 kPa (gauge pressure), the depropylenating contact tower has 14 theoretical plates. The volume ratio of the raw material dry gas to the depropylenating agent is 65.

[0116] The total sulfur volume content in the depropylenated and purified dry gas obtained in this example is 0.5 ppm.

[0117]

Example 3

[0118] The dry gas raw material in this example is the same as that in Example 1. The separation process in this example is the same as that in Example 1.

[0119] The desulfurization and refining device is filled with modified hollow ceramic fibers. The dry gas raw material flows through the inner cavity of the modified hollow ceramic fibers, and the sulfur-containing impurities are adsorbed by the adsorption active centers coated on the inner wall of the fibers. The regenerant solution penetrates to the inner wall of the fibers under the action of the liquid pressure and the capillary force of the ceramic membrane pores to regenerate the saturated active centers of the adsorption.

[0120] Preparation method of modified hollow ceramic fibers, comprising: first treating hollow ceramic fibers with a silane reagent to obtain silanized hollow ceramic fibers, and then successively performing a first modification treatment, a first post-modification treatment, a second modification treatment, a third modification treatment, a third post-modification treatment, an activation treatment, and a demineralized water treatment to obtain modified hollow ceramic fibers. The inner diameter of the hollow ceramic fibers is 0.9 mm, the outer diameter is 1.9 mm, the average pore diameter of the fiber membrane wall is 950 nm, the porosity is 52%, and the material is silica. The preparation of the hollow ceramic membrane is as follows: Polyethersulfone (molecular weight of 45000), N-methylpyrrolidone, silica, and polyvinylpyrrolidone K90 are formulated into a raw material solution in a mass ratio of 12:150:240:1.5, stirred at 85°C for 35 hours, and then left to stand for defoaming for 9 hours to obtain a casting solution. The inner and outer coagulation baths of the spinneret are deionized water at 2.5°C, the inner diameter of the spinneret is 0.9 mm, the outer diameter is 1.9 mm, the flow rate of the casting solution is 9.5 ml / min, the pressure of the casting solution inside the spinneret is 250 kPa (gauge pressure), the ambient temperature is 28°C, the ambient humidity is 65%, and the casting solution exchanges solvents with the inner and outer coagulation baths and phase-separates and cures to form a hollow fiber blank. After the hollow fiber blank is washed 7 times with demineralized water, it is air-dried at 28°C, then heated from 28°C to 1750°C at a rate of 0.9°C / min, held at a constant temperature for 5.0 hours, and then naturally cooled to 28°C to obtain hollow ceramic fibers. The silanization treatment of the hollow ceramic fibers is to perform a flow treatment on the hollow ceramic fibers in a silane reagent (γ-methacryloxypropylmethyldiethoxysilane) solution, and then dry and cure to obtain silane-pretreated hollow ceramic fibers with a molar ratio of siloxane groups to silicon-carbon groups of 0.7 and a thickness of 14 μm of a silane film. Among them, the silanization treatment conditions are as follows: The composition of the silane reagent solution, by volume fraction, is silane reagent: demineralized water: absolute ethanol = 5:13:82, the pH value is 7.5, and the pre-hydrolysis time is 25 hours. The hollow ceramic fibers are first passed through petroleum ether with a boiling point of 80-90°C at an inner surface fluid linear velocity of 0.24 m / s for continuous replacement for 2.2 hours, and then passed through the silane reagent solution at an inner surface fluid linear velocity of 0.38 m / s for a feeding time of 4 minutes. The drying and curing temperature is 115°C, the drying time is 35 minutes, and the drying atmosphere is nitrogen. The replacement drying of petroleum ether and the silane reagent solution is continuously processed 4 times.

[0121] The first modifier in this embodiment is 1-(3-buten-1-yl)-2,4-dichlorobenzene, benzoyl peroxide and toluene. By mass, 1-(3-buten-1-yl)-2,4-dichlorobenzene: benzoyl peroxide: toluene = 16:1.5:190. The treatment conditions for the first modifier are as follows: control the fluid linear velocity of the first modifier on the inner surface of the silylated hollow ceramic fiber membrane to be 0.75 m / s, the treatment temperature to be 35 °C, and the treatment time to be 2.5 hours. The phenyl content introduced into the modified hollow ceramic fiber after treatment with the first modifier is 0.15 mol / m 2 , and the thickness is 4 microns. After treating the ceramic fiber with the modifier, a first-modified silylated hollow ceramic fiber intermediate is obtained.

[0122] The first-modified silylated hollow ceramic fiber intermediate is subjected to a second modification treatment after the first post-treatment to obtain a second-modified silylated hollow ceramic fiber intermediate. The post-treatment agent used for the first post-treatment is anhydrous ethanol. The first post-treatment conditions are as follows: liquid ethanol is pumped into the inner cavity of the hollow ceramic fiber through a conventional pump, the temperature is 65 °C, the linear velocity is 0.6 m / s, the continuous treatment time is 1.5 hours, and after ethanol treatment, it is purged and dried with nitrogen at 115 °C for 0.6 hours. The second modifier is N,N-bis(4-aminophenyl)-1,4-phenylenediamine, polyoxyethylene polyoxypropylene ether (average molecular weight 2650), zinc chloride and toluene. By mass, N,N-bis(4-aminophenyl)-1,4-phenylenediamine: polyoxyethylene polyoxypropylene ether: zinc chloride: toluene = 22:3:12:280. The zinc chloride used is anhydrous zinc chloride. The treatment conditions for the second modifier are as follows: control the fluid linear velocity of the second modifier on the inner surface of the silylated hollow ceramic fiber to be 1.3 m / s, the treatment temperature to be 58 °C, the treatment time to be 2.5 hours, and the treatment pressure (gauge pressure) to be 550 kPa. The content of secondary amino groups introduced into the modified hollow ceramic fiber after treatment with the second modifier is 0.32 mol / m 2 , the content of primary amino groups is 0.11 mol / m 2 , and the content of tertiary amino groups is 0.10 mol / m 2 .

[0123] The second modified silanized hollow ceramic fiber intermediate is subjected to a third modification treatment to obtain a third modified silanized hollow ceramic fiber intermediate. The third modifier is N-amidino-2-(2,6-dichlorophenyl)acetamide, tetrahydrofuran, 3,5-dichloro-2-methoxyaniline, and zinc chloride. By mass fraction, N-amidino-2-(2,6-dichlorophenyl)acetamide:tetrahydrofuran:3,5-dichloro-2-methoxyaniline:zinc chloride = 11:280:42:12. The treatment conditions for the third modifier treatment are as follows: controlling the fluid linear velocity of the third modifier on the inner surface of the silanized hollow ceramic fiber to be 1.8 m / s, the treatment temperature to be 65 °C, the treatment time to be 6.5 hours, and the treatment pressure (gauge pressure) to be 450 kPa. The content of secondary amino groups introduced into the modified hollow ceramic fiber after treatment with the third modifier is 12 mmol / m 2 , and the content of imino groups is 4.3 mmol / m 2 , and the content of methoxy groups is 13.5 mmol / m 2 .

[0124] The third modified silanized hollow ceramic fiber intermediate is subjected to a third post-modification treatment to obtain a pre-activated modified silanized hollow ceramic fiber intermediate. The pre-activator used in the third post-modification treatment is anhydrous ethanol. The third post-modification treatment conditions are as follows: liquid ethanol is transported to the inner cavity of the hollow ceramic fiber by a conventional pump, the temperature is 65 °C, the linear velocity is 0.6 m / s, the continuous treatment time is 1.5 hours, and after the ethanol treatment, it is purged and dried with nitrogen at 115 °C for 0.6 hours.

[0125] The pre-activated modified silanized hollow ceramic fiber intermediate is subjected to an activation treatment and a desalted water treatment to obtain a modified hollow ceramic fiber. The activator is a 4.5% (mass concentration) aqueous sodium hydroxide solution. The treatment conditions for the activator treatment are as follows: the aqueous sodium hydroxide solution is transported to the inner cavity of the hollow ceramic fiber by a conventional pump, the treatment temperature is 35 °C, the linear velocity is 0.15 m / s, the treatment time is 2.2 hours, and then desalted water is transported to the inner cavity of the hollow ceramic fiber by a conventional pump, the linear velocity is 0.13 m / s, and the treatment temperature is 45 °C.

[0126] In this example, the dry gas raw material feed volume space velocity is 800 h -1 , and the cross-sectional arrangement density of the ceramic fibers of the hollow ceramic fiber regular module is 40,000 roots / m 2。The adsorption temperature when dry gas passes through the inner cavity of the ceramic fiber is 25°C, and the adsorption pressure (gauge pressure) is 600 kPa. The regenerant includes diethanolamine, N-methyldiethanolamine, potassium carbonate, and demineralized water. In terms of the mass composition percentage of the regenerant solution, N-methyldiethanolamine is 25%, diethanolamine is 3.5%, potassium carbonate is 3.5%, and the rest is demineralized water. The regeneration conditions are as follows: the temperature is 25°C, the pressure difference relative to the raw material dry gas (the difference between the regenerant liquid pressure and the raw material dry gas pressure) is -90 kPa, and the feed volume ratio of the dry gas raw material to the regenerant solution is 550 by volume.

[0127] The degumming powder tower in this example is a conventional packed tower, with 2 theoretical plates, an operating temperature of 25°C, fresh water as the degumming powder, and a gas-water ratio of 56. The dry gas filter is a conventional bag filter with a separation accuracy of 4 microns.

[0128] The cyclone separator in this example is a conventional liquid separation device in the art, with a separation accuracy of 200 microns.

[0129] The operating conditions of the desulfurized and purified dry gas in the water wash tower are as follows: the temperature is 45°C, the pressure is 600 kPa by gauge pressure, the water is demineralized water, and the water wash tower has 7 theoretical plates. The volume ratio of the desulfurized and purified dry gas to the demineralized water is 75 by volume.

[0130] The depropanizer is a conventional depropanizer in the art, preferably benzene. The conditions for the raw material dry gas to contact the depropanizer are as follows: the temperature is 22°C, the pressure is 800 kPa by gauge pressure, the depropanization contact tower has 9 theoretical plates. The volume ratio of the raw material dry gas to the depropanizer is 85 by volume.

[0131] The total sulfur volume content in the depropanized and purified dry gas obtained in this example is 6 ppm.

[0132]

Example 4

[0133] The modified hollow ceramic fiber used in this example is the same as that in Example 2.

[0134] The separation process for dry gas raw materials in this example is the same as that in Example 2. Compared with Example 2, the only difference is the dry gas raw material used. Among them, the dry gas composition by volume percentage includes: methane 16.6244%, ethane 7.5433%, carbonyl sulfide 0.2577%, ethylene 14.8774%, propane 0.1729%, propylene 0.7825%, isobutane 0.0754%, carbon disulfide 0.1309%, n-butane 0.0146%, trans-butene 0.0062%, n-butene 0.0172%, isobutene 0.0354%, cis-butene 0.0002%, oxygen 0.1274%, nitrogen 12.5934%, hydrogen sulfide 12.8866%, hydrogen 27.3889%, carbon monoxide 1.3922%, carbon dioxide 3.0938%, acetylene 0.0049%, 1,3-butadiene 0.0001%, alkanes or alkenes with more than five carbons 1.1101%, and other components 0.8644%. The volume content of sulfur-containing impurities calculated as total sulfur element is 124000 ppm.

[0135] The total sulfur volume content in the depropylene purified dry gas obtained in this example is 3.8 ppm.

[0136]

Example 5

[0137] The modified hollow ceramic fibers used in this example are the same as those in Example 2.

[0138] The separation process for dry gas raw materials in this example is the same as that in Example 2. Compared with Example 2, the only difference is the dry gas raw material used. Among them, the dry gas composition by volume percentage includes: methane 19.1554%, ethane 8.6917%, ethylene 17.1423%, propane 0.1992%, propylene 0.9017%, isobutane 0.0869%, n-butane 0.0168%, trans-butene 0.0071%, hydrogen sulfide 0.0699%, n-butene 0.0198%, isobutene 0.0408%, cis-butene 0.0002%, oxygen 0.1468%, carbon disulfide 0.0007%, nitrogen 14.5107%, hydrogen 31.5587%, carbon monoxide 1.6041%, carbon dioxide 3.5648%, carbonyl sulfide 0.0014%, acetylene 0.0057%, 1,3-butadiene 0.0001%, alkanes or alkenes with more than five carbons 1.2791%, and other components 0.9960%. The volume content of sulfur-containing impurities calculated as total sulfur element is 730 ppm.

[0139] The total sulfur volume content in the depropylene purified dry gas obtained in this example is 0.01 ppm.

[0140]

Example 6

[0141] The modified hollow ceramic fibers used in this example are the same as those in Example 2.

[0142] The separation process for dry gas raw materials in this embodiment is the same as that in Embodiment 2. Compared with Embodiment 2, the only difference is that the regenerant solution uses an N-methyldiethanolamine solution with a mass concentration of 25%.

[0143] The total sulfur volume content in the purified dry gas from which propylene has been removed is 6.2 ppm.

[0144]

Example 7

[0145] The modified hollow ceramic fiber used in this embodiment, compared with that in Embodiment 2, only differs in that the first modifier is different, and 3-(3,5-dichlorophenyl)-1-propene is used to replace an equal mass of 1-(3-buten-1-yl)-2,4-dichlorobenzene.

[0146] The separation process for dry gas raw materials in this embodiment is the same as that in Embodiment 2.

[0147] The total sulfur volume content in the purified dry gas from which propylene has been removed is 3.2 ppm.

[0148]

Example 8

[0149] The modified hollow ceramic fiber used in this embodiment, compared with that in Embodiment 2, only differs in that the first modifier is different, and 3-(3,4-dichlorophenyl)-1-propene is used to replace an equal mass of 1-(3-buten-1-yl)-2,4-dichlorobenzene.

[0150] The separation process for dry gas raw materials in this embodiment is the same as that in Embodiment 2.

[0151] The total sulfur volume content in the purified dry gas from which propylene has been removed is 3.5 ppm.

[0152]

Example 9

[0153] The modified hollow ceramic fiber used in this embodiment, compared with that in Embodiment 2, only differs in that the second modifier is different, and N1-(2-aminoethyl)-N1-(2-aminophenyl)-1,2-benzenediamine is used to replace an equal mass of N,N-bis(4-aminophenyl)-1,4-benzenediamine.

[0154] The separation process for dry gas raw materials in this embodiment is the same as that in Embodiment 2.

[0155] The total sulfur volume content in the purified dry gas from which propylene has been removed is 7.3 ppm.

[0156]

Example 10

[0157] The modified hollow ceramic fibers used in this example are only different from those in Example 2 in that the second modifier is different, and 3,5-diamino-N-(4-aminophenyl)benzamide is used to replace an equal mass of N,N-bis(4-aminophenyl)-1,4-benzenediamine.

[0158] The separation process for dry gas raw materials in this example is the same as that in Example 2.

[0159] The total sulfur volume content in the purified dry gas from which propylene has been removed is 6.4 ppm.

[0160]

Example 11

[0161] The modified hollow ceramic fibers used in this example are only different from those in Example 2 in that the third modifier is different, and 2-[2-(2,6-dichlorophenyl)ethyl]hydrazinecarboximidamide is used to replace an equal mass of N-guanyl-2-(2,6-dichlorophenyl)acetamide.

[0162] The separation process for dry gas raw materials in this example is the same as that in Example 2.

[0163] The total sulfur volume content in the purified dry gas from which propylene has been removed is 3.7 ppm.

[0164]

Example 12

[0165] The modified hollow ceramic fibers used in this example are only different from those in Example 2 in that the third modifier is different, and N1,N2-bis(4-chlorophenyl)acetamidine is used to replace an equal mass of N-guanyl-2-(2,6-dichlorophenyl)acetamide.

[0166] The separation process for dry gas raw materials in this example is the same as that in Example 2.

[0167] The total sulfur volume content in the purified dry gas from which propylene has been removed is 5.2 ppm.

[0168]

Example 13

[0169] The dry gas raw materials described in this example are the same as those in Example 1. The separation process in this example is the same as that in Example 1.

[0170] The desulfurization and refining device is filled with modified hollow ceramic fibers. The dry gas raw material flows through the inner cavity of the modified hollow ceramic fibers, and the sulfur-containing impurities are adsorbed by the adsorption active centers coated on the inner wall of the fiber. The regenerant solution penetrates to the inner wall of the fiber under the action of liquid pressure and the capillary force of the ceramic membrane pores to regenerate the saturated active centers adsorbed.

[0171] Preparation method of modified hollow ceramic fibers, comprising: the hollow ceramic fibers are first treated with a silane reagent to obtain silanized hollow ceramic fibers, and then successively subjected to a first modification treatment, a first post-modification treatment, a second modification treatment, a third post-modification treatment, an activation treatment and a demineralized water treatment to obtain the modified hollow ceramic fibers. The inner diameter of the hollow ceramic fibers is 0.9 mm, the outer diameter is 1.9 mm, the average pore diameter of the fiber membrane wall is 950 nm, the porosity is 52%, and the material is silica. The preparation of the hollow ceramic membrane is as follows: Polyethersulfone (molecular weight of 45000), N-methylpyrrolidone, silica, and polyvinylpyrrolidone K90 are formulated into a raw material solution according to a mass ratio of 12:150:240:1.5, stirred at 85 °C for 35 hours, and then left to stand for defoaming for 9 hours to obtain a casting solution. The inner and outer coagulation baths of the spinneret are deionized water at 2.5 °C, the inner diameter of the spinneret is 0.9 mm, the outer diameter is 1.9 mm, the flow rate of the casting solution is 9.5 ml / min, the pressure of the casting solution inside the spinneret is 250 kPa (gauge pressure), the ambient temperature is 28 °C, the ambient humidity is 65%, and the casting solution exchanges solvents with the inner and outer coagulation baths and phase-separates and cures to form a hollow fiber blank. After the hollow fiber blank is washed 7 times with demineralized water and air-dried at 28 °C, it is then heated from 28 °C to 1750 °C at a programmed heating rate of 0.9 °C / min, held at a constant temperature for 5.0 hours, and then naturally cooled to 28 °C to obtain the hollow ceramic fibers. The silanization treatment of the hollow ceramic fibers is to flow-treat the hollow ceramic fibers in a silane reagent (γ-methacryloxypropylmethyldiethoxysilane) solution, and then dry and cure to obtain the silane-pretreated hollow ceramic fibers with a molar ratio of siloxyl groups to silicon-carbon groups of 0.7 and a thickness of 14 μm of the silane film. Among them, the silanization treatment conditions are as follows: the composition of the silane reagent solution, by volume fraction, is silane reagent: demineralized water: absolute ethanol = 5:13:82, the pH value is 7.5, and the pre-hydrolysis time is 25 hours. The hollow ceramic fibers are first passed through petroleum ether with a boiling point of 80-90 °C at an inner surface linear velocity of 0.24 m / s for continuous replacement for 2.2 hours, and then passed through the silane reagent solution at an inner surface linear velocity of 0.38 m / s for a feeding time of 4 minutes. The drying and curing temperature is 115 °C, the drying time is 35 minutes, and the drying atmosphere is nitrogen. The replacement and drying of petroleum ether and the silane reagent solution are continuously processed 4 times.

[0172] The first modifier in this embodiment is 1-(3-buten-1-yl)-2,4-dichlorobenzene, benzoyl peroxide and toluene. By mass, 1-(3-buten-1-yl)-2,4-dichlorobenzene:benzoyl peroxide:toluene = 16:1.5:190. The treatment conditions for the first modifier are as follows: control the fluid linear velocity of the first modifier on the inner surface of the silylated hollow ceramic fiber membrane obtained in step (1) to be 0.75 m / s, the treatment temperature to be 35 °C, and the treatment time to be 2.5 hours. The phenyl content introduced into the modified hollow ceramic fiber after treatment with the first modifier is 0.15 mol / m 2 , and the thickness is 4 microns. After treating the ceramic fiber with the modifier, a first-modified silylated hollow ceramic fiber intermediate is obtained.

[0173] The first-modified silylated hollow ceramic fiber intermediate is subjected to a second modification treatment after the first post-treatment to obtain a second-modified silylated hollow ceramic fiber intermediate. The post-treatment agent used for the first post-treatment is anhydrous ethanol. The first post-treatment conditions are as follows: liquid ethanol is transported to the inner cavity of the hollow ceramic fiber through a conventional pump, the temperature is 65 °C, the linear velocity is 0.6 m / s, the continuous treatment time is 1.5 hours, and after ethanol treatment, it is purged and dried with nitrogen at 115 °C for 0.6 hours. The second modifier is N,N-bis(4-aminophenyl)-1,4-phenylenediamine, polyoxyethylene polyoxypropylene ether (average molecular weight is 2650), zinc chloride and toluene. By mass, N,N-bis(4-aminophenyl)-1,4-phenylenediamine:polyoxyethylene polyoxypropylene ether:zinc chloride:toluene = 22:3:12:280. The zinc chloride used is anhydrous zinc chloride. The treatment conditions for the second modifier are as follows: control the fluid linear velocity of the second modifier on the inner surface of the silylated hollow ceramic fiber to be 1.3 m / s, the treatment temperature to be 58 °C, the treatment time to be 2.5 hours, and the treatment pressure (gauge pressure) to be 550 kPa. The content of secondary amino groups introduced into the modified hollow ceramic fiber after treatment with the second modifier is 0.32 mol / m 2 , the content of primary amino groups is 0.11 mol / m 2 , and the content of tertiary amino groups is 0.10 mol / m 2 .

[0174] The second-modified silylated hollow ceramic fiber intermediate is subjected to a third post-treatment to obtain a pre-activated modified silylated hollow ceramic fiber intermediate. The pre-activator used for the third post-treatment is anhydrous ethanol. The third post-treatment conditions are as follows: liquid ethanol is transported to the inner cavity of the hollow ceramic fiber through a conventional pump, the temperature is 65 °C, the linear velocity is 0.6 m / s, the continuous treatment time is 1.5 hours, and after ethanol treatment, it is purged and dried with nitrogen at 115 °C for 0.6 hours.

[0175] The pre-activated modified silylated hollow ceramic fiber intermediate is subjected to activation treatment and desalted water treatment to obtain modified hollow ceramic fibers. The activator is a 4.5% (mass concentration) aqueous sodium hydroxide solution. The treatment conditions for the activator treatment are as follows: The aqueous sodium hydroxide solution is transported to the inner cavity of the hollow ceramic fiber by a conventional pump, the treatment temperature is 35 °C, the liquid flow rate is 12 mL / min, the treatment time is 2.2 hours, and then desalted water is transported to the inner cavity of the hollow ceramic fiber by a conventional pump, the liquid flow rate is 12 mL / min, and the treatment temperature is 45 °C.

[0176] In this embodiment, the dry gas feed volume space velocity is 800 h -1 , and the cross-sectional arrangement density of the ceramic fibers in the hollow ceramic fiber regular module is 40,000 roots / m 2 . When the dry gas passes through the inner cavity of the ceramic fiber, the adsorption temperature is 25 °C, and the adsorption pressure (gauge pressure) is 600 kPa. The regenerant includes diethanolamine, N-methyldiethanolamine, potassium carbonate, and desalted water. In terms of the mass composition percentage of the regenerant solution, N-methyldiethanolamine is 25%, diethanolamine is 3.5%, potassium carbonate is 3.5%, and the rest is desalted water. The regeneration conditions are as follows: the temperature is 25 °C, the pressure difference relative to the raw material dry gas (the difference between the regenerant liquid pressure and the raw material dry gas pressure) is -90 kPa, and the feed volume ratio of the raw material dry gas to the regenerant solution is 550 by volume.

[0177] The degumming powder tower in this embodiment is a conventional packed tower, the number of theoretical plates is 2, the operating temperature is 25 °C, the degumming powder is fresh water, and the gas-water ratio is 56. The dry gas filter is a conventional bag filter, and the separation accuracy is 4 microns.

[0178] The cyclone separator in this embodiment is a conventional liquid separation device, and the separation accuracy is 200 microns.

[0179] The operating conditions of the desulfurized and purified dry gas in the water wash tower are as follows: the temperature is 45 °C, the pressure is 600 kPa by gauge pressure, the water is desalted water, and the number of theoretical plates of the water wash tower is 7. The volume ratio of the desulfurized and purified dry gas to the desalted water is 75 by volume.

[0180] The depropylenating agent is benzene. The conditions for the raw material dry gas to contact the depropylenating agent are as follows: the temperature is 22 °C, the pressure is 800 kPa by gauge pressure, and the number of theoretical plates of the depropylenating contact tower is 9. The volume ratio of the raw material dry gas to the depropylenating agent is 85 by volume.

[0181] The total sulfur volume content in the depropylenated and purified dry gas obtained in this embodiment is 13 ppm.

[0182]

Example 14

[0183] The modified hollow ceramic fibers used in this embodiment are the same as those in Example 13.

[0184] The separation process of the dry gas raw material in this embodiment is the same as that in Embodiment 13. Compared with Embodiment 13, the only difference lies in the different dry gas raw materials used. Among them, the dry gas composition by volume percentage includes: methane 19.1554%, ethane 8.6917%, ethylene 17.1423%, propane 0.1992%, propylene 0.9017%, isobutane 0.0869%, n-butane 0.0168%, trans-butene 0.0071%, hydrogen sulfide 0.0699%, n-butene 0.0198%, isobutene 0.0408%, cis-butene 0.0002%, oxygen 0.1468%, carbon disulfide 0.0007%, nitrogen 14.5107%, hydrogen 31.5587%, carbon monoxide 1.6041%, carbon dioxide 3.5648%, carbonyl sulfide 0.0014%, acetylene 0.0057%, 1,3-butadiene 0.0001%, paraffins or olefins with more than five carbon atoms 1.2791%, and other components 0.9960%. The volume content of sulfur-containing impurities calculated as total sulfur element is 730 ppm.

[0185] The total sulfur volume content in the purified dry gas after removing propylene obtained in this embodiment is 2.3 ppm.

[0186]

Embodiment 15

[0187] The dry gas raw material described in this embodiment is the same as that in Embodiment 1. The separation process in this embodiment is the same as that in Embodiment 1.

[0188] The desulfurization and refining device is filled with modified hollow ceramic fibers. The dry gas raw material flows through the inner cavity of the modified hollow ceramic fibers. The sulfur-containing impurities are adsorbed by the adsorption active centers coated on the inner wall of the fiber. The regenerant solution penetrates to the inner wall of the fiber under the action of liquid pressure and capillary force of the ceramic membrane pores to regenerate the saturated active centers adsorbed.

[0189] Preparation method of modified hollow ceramic fiber, comprising: the hollow ceramic fiber is first treated with a silane reagent to obtain a silylated hollow ceramic fiber, and then successively subjected to a first modification treatment, a second modification treatment and an activation treatment to obtain a modified hollow ceramic fiber. The inner diameter of the hollow ceramic fiber is 0.9 mm, the outer diameter is 1.9 mm, the average pore diameter of the fiber membrane wall is 950 nm, the porosity is 52%, and the material is silica. The preparation of the hollow ceramic membrane is as follows: Polyethersulfone (molecular weight 45000), N-methylpyrrolidone, silica, polyvinylpyrrolidone K90 are formulated into a raw material solution according to a mass ratio of 12:150:240:1.5, stirred at 85 °C for 35 hours, and then left to stand for defoaming for 9 hours to obtain a casting solution. The inner and outer coagulation baths of the spinneret are deionized water at 2.5 °C, the inner diameter of the spinneret is 0.9 mm, the outer diameter is 1.9 mm, the flow rate of the casting solution is 9.5 ml / min, the pressure of the casting solution inside the spinneret is 250 kPa (gauge pressure), the ambient temperature is 28 °C, the ambient humidity is 65%, and the casting solution exchanges solvents with the inner and outer coagulation baths and phase-separates and cures to form a hollow fiber blank. The hollow fiber blank is washed 7 times with demineralized water, air-dried at 28 °C, then heated from 0.9 °C / min to 1750 °C at a programmed rate, held at a constant temperature for 5.0 hours, and then naturally cooled to 28 °C to obtain a hollow ceramic fiber. The silylation treatment of the hollow ceramic fiber is to flow-treat the hollow ceramic fiber in a silane reagent (γ-methacryloxypropylmethyldiethoxysilane) solution, and then dry and cure to obtain a silylated pretreated hollow ceramic fiber with a molar ratio of siloxyl group to silicon-carbon group of 0.7 and a thickness of 14 μm of a silane film. Among them, the silylation treatment conditions are as follows: the composition of the silane reagent solution, by volume fraction, silane reagent: demineralized water: absolute ethanol = 5:13:82, pH value is 7.5, and the pre-hydrolysis time is 25 hours. The hollow ceramic fiber is first introduced with petroleum ether with a boiling point of 80-90 °C at an inner surface fluid linear velocity of 0.24 m / s for continuous replacement for 2.2 hours, and then the silane reagent solution is introduced at an inner surface fluid linear velocity of 0.38 m / s, and the feeding time is 4 minutes. The drying and curing temperature is 115 °C, the drying time is 35 minutes, and the drying atmosphere is nitrogen. The replacement drying of petroleum ether and silane reagent solution is continuously carried out 4 times.

[0190] The first modifier described in this example is 1-(3-buten-1-yl)-2,4-dichlorobenzene, benzoyl peroxide and toluene. By mass fraction, 1-(3-buten-1-yl)-2,4-dichlorobenzene: benzoyl peroxide: toluene = 16:1.5:190. The treatment conditions for the first modifier treatment are as follows: control the inner surface fluid linear velocity of the silylated hollow ceramic fiber membrane obtained in step (1) with the first modifier to be 0.75 m / s, the treatment temperature to be 35 °C, and the treatment time to be 2.5 hours. The phenyl content introduced into the modified hollow ceramic fiber after the first modifier treatment is 0.15 mol / m 2, with a thickness of 4 microns. After treating the ceramic fibers with a modifier, a first modified silanized hollow ceramic fiber intermediate is obtained.

[0191] The first modified silanized hollow ceramic fiber intermediate is subjected to a second modification treatment to obtain a second modified silanized hollow ceramic fiber intermediate. The second modifier is N,N-bis(4-aminophenyl)-1,4-phenylenediamine, polyoxyethylene polyoxypropylene ether (average molecular weight of 2650), zinc chloride, and toluene. By mass fraction, N,N-bis(4-aminophenyl)-1,4-phenylenediamine: polyoxyethylene polyoxypropylene ether: zinc chloride: toluene = 22:3:12:280. The zinc chloride used is anhydrous zinc chloride. The treatment conditions for the second modifier treatment are as follows: controlling the fluid linear velocity of the second modifier on the inner surface of the silanized hollow ceramic fiber obtained in step (2) to be 1.3 m / s, the treatment temperature to be 58 °C, the treatment time to be 2.5 hours, and the treatment pressure (gauge pressure) to be 550 kPa. After treatment with the second modifier, the content of secondary amino groups introduced into the modified hollow ceramic fiber is 0.31 mol / m 2 , the content of primary amino groups is 0.10 mol / m 2 , the content of tertiary amino groups is 0.97 mol / m 2 .

[0192] The second modified silanized hollow ceramic fiber intermediate is subjected to an activation treatment to obtain a modified hollow ceramic fiber. The activator is a 4.5% (mass concentration) aqueous sodium hydroxide solution. The treatment conditions for the activator treatment are as follows: the aqueous sodium hydroxide solution is transported to the inner cavity of the hollow ceramic fiber by a conventional pump, the treatment temperature is 35 °C, the liquid flow rate is 12 mL / min, and the treatment time is 2.2 hours.

[0193] In this example, the dry gas feed volume space velocity is 800 h -1 , the cross-sectional arrangement density of the ceramic fibers of the hollow ceramic fiber regular module is 40,000 roots / m 2 . When the dry gas passes through the inner cavity of the ceramic fiber, the adsorption temperature is 25 °C, and the adsorption pressure (gauge pressure) is 600 kPa. The regenerant includes diethanolamine, N-methyldiethanolamine, potassium carbonate, and demineralized water. By mass composition percentage of the regenerant solution, N-methyldiethanolamine is 25%, diethanolamine is 3.5%, potassium carbonate is 3.5%, and the rest is demineralized water. The regeneration conditions are as follows: the temperature is 25 °C, the pressure difference relative to the raw material dry gas (the difference between the regenerant liquid pressure and the raw material dry gas pressure) is -90 kPa, and the feed volume ratio of the raw material dry gas to the regenerant solution is 550 by volume.

[0194] The degumming powder tower in this example is a conventional packed tower, with 2 theoretical plates, an operating temperature of 25 °C, the degumming powder is fresh water, and the gas-water ratio is 56. The dry gas filter is a conventional bag filter with a separation accuracy of 4 microns.

[0195] The cyclone separator in this embodiment is a conventional liquid removal device with a separation accuracy of 200 microns.

[0196] The operating conditions of the desulfurized and purified dry gas in the water washing tower are as follows: the temperature is 45 °C, the pressure is, gauge pressure, 600 kPa, the water is demineralized water, and the number of theoretical plates of the water washing tower is 7. The volume ratio of the desulfurized and purified dry gas to the demineralized water is 75.

[0197] The depropylenating agent is benzene. The conditions for the raw material dry gas to contact the depropylenating agent are as follows: the temperature is 22 °C, the pressure is, gauge pressure, 800 kPa, and the number of theoretical plates of the depropylenating contact tower is 9. The volume ratio of the raw material dry gas to the depropylenating agent is 85.

[0198] The total sulfur volume content in the depropylenated and purified dry gas obtained in this embodiment is 14 ppm.

[0199]

Example 16

[0200] The dry gas raw material described in this embodiment is the same as that in Example 1. The separation process in this embodiment is the same as that in Example 1.

[0201] The desulfurization refiner is filled with modified hollow ceramic fibers. The dry gas raw material flows through the inner cavity of the modified hollow ceramic fibers, and the sulfur-containing impurities are adsorbed by the adsorption active centers coated on the inner wall of the fibers. The regenerant solution penetrates to the inner wall of the fibers under the action of liquid pressure and capillary force of the ceramic membrane pores to regenerate the saturated active centers adsorbed.

[0202] Preparation method of modified hollow ceramic fibers, comprising: the hollow ceramic fibers are first treated with a silane reagent to obtain silanized hollow ceramic fibers, and then successively subjected to a first modification treatment, a second modification treatment, a third modification treatment and an activation treatment to obtain modified hollow ceramic fibers. The inner diameter of the hollow ceramic fibers is 0.9 mm, the outer diameter is 1.9 mm, the average pore diameter of the fiber membrane wall is 950 nm, the porosity is 52%, and the material is silica. The preparation of the hollow ceramic membrane is as follows: Polyethersulfone (molecular weight of 45000), N-methylpyrrolidone, silica, and polyvinylpyrrolidone K90 are formulated into a raw material solution according to a mass ratio of 12:150:240:1.5, stirred at 85 °C for 35 hours, and then left standing for defoaming for 9 hours to obtain a casting solution. The inner and outer coagulation baths of the spinneret are deionized water at 2.5 °C, the inner diameter of the spinneret is 0.9 mm, the outer diameter is 1.9 mm, the flow rate of the casting solution is 9.5 ml / min, the pressure of the casting solution inside the spinneret is 250 kPa (gauge pressure), the ambient temperature is 28 °C, the ambient humidity is 65%, and the casting solution exchanges solvents with the inner and outer coagulation baths and phase-separates and cures to form a hollow fiber blank. After the hollow fiber blank is washed 7 times with demineralized water, it is air-dried at 28 °C, then heated from 0.9 °C / min to 1750 °C at a programmed rate, held at a constant temperature for 5.0 hours, and then naturally cooled to 28 °C to obtain hollow ceramic fibers. The silanization treatment of the hollow ceramic fibers is to perform a flow treatment of the hollow ceramic fibers in a silane reagent (γ-methacryloxypropylmethyldiethoxysilane) solution, and then dry and cure to obtain a silane-pretreated hollow ceramic fiber with a silane film having a molar ratio of siloxyl group to silicon-carbon group of 0.7 and a thickness of 14 μm. Among them, the silane treatment conditions are as follows: the composition of the silane reagent solution, by volume fraction, is silane reagent: deionized water: absolute ethanol = 5:13:82, the pH value is 7.5, and the pre-hydrolysis time is 25 hours. The hollow ceramic fibers are first passed through petroleum ether with a boiling point of 80-90 °C at an inner surface fluid linear velocity of 0.24 m / s for continuous replacement for 2.2 hours, and then passed through the silane reagent solution at an inner surface fluid linear velocity of 0.38 m / s for a feeding time of 4 minutes. The drying and curing temperature is 115 °C, the drying time is 35 minutes, and the drying atmosphere is nitrogen. The replacement and drying of petroleum ether and silane reagent solution are continuously treated 4 times.

[0203] The first modifier described in this example is 1-(3-buten-1-yl)-2,4-dichlorobenzene, benzoyl peroxide and toluene. By mass fraction, 1-(3-buten-1-yl)-2,4-dichlorobenzene: benzoyl peroxide: toluene = 16:1.5:190. The treatment conditions for the first modifier treatment are as follows: control the inner surface fluid linear velocity of the silanized hollow ceramic fiber membrane obtained in step (1) with the first modifier to be 0.75 m / s, the treatment temperature to be 35 °C, and the treatment time to be 2.5 hours. The phenyl content introduced into the modified hollow ceramic fibers after the first modifier treatment is 0.15 mol / m 2, with a thickness of 4 microns. After treating the ceramic fibers with a modifier, a first modified silanized hollow ceramic fiber intermediate is obtained.

[0204] The first modified silanized hollow ceramic fiber intermediate is subjected to a second modification treatment to obtain a second modified silanized hollow ceramic fiber intermediate. The second modifier is N,N-bis(4-aminophenyl)-1,4-phenylenediamine, polyoxyethylene polyoxypropylene ether (average molecular weight of 2650), zinc chloride, and toluene. By mass fraction, N,N-bis(4-aminophenyl)-1,4-phenylenediamine: polyoxyethylene polyoxypropylene ether: zinc chloride: toluene = 22:3:12:280. The zinc chloride used is anhydrous zinc chloride. The treatment conditions for the second modifier treatment are as follows: control the fluid linear velocity of the second modifier on the inner surface of the silanized hollow ceramic fiber obtained in step (2) to be 1.3 m / s, the treatment temperature to be 58 °C, the treatment time to be 2.5 hours, and the treatment pressure (gauge pressure) to be 550 kPa. After treatment with the second modifier, the content of secondary amino groups introduced into the modified hollow ceramic fiber is 0.31 mol / m 2 , the content of primary amino groups is 0.10 mol / m 2 , the content of tertiary amino groups is 0.97 mol / m 2 .

[0205] The second modified silanized hollow ceramic fiber intermediate is subjected to a third modification treatment to obtain a third modified silanized hollow ceramic fiber intermediate. The third modifier is N-amidino-2-(2,6-dichlorophenyl)acetamide, tetrahydrofuran, 3,5-dichloro-2-methoxyaniline, and zinc chloride. By mass fraction, N-amidino-2-(2,6-dichlorophenyl)acetamide: tetrahydrofuran: 3,5-dichloro-2-methoxyaniline: zinc chloride = 11:280:42:12. The treatment conditions for the third modifier treatment are as follows: control the fluid linear velocity of the third modifier on the inner surface of the silanized hollow ceramic fiber obtained in step (3) to be 1.8 m / s, the treatment temperature to be 65 °C, the treatment time to be 6.5 hours, and the treatment pressure (gauge pressure) to be 450 kPa. After treatment with the third modifier, the content of secondary amino groups introduced into the modified hollow ceramic fiber is 11.6 mmol / m 2 , the content of imino groups is 4.2 mmol / m 2 , the content of methoxy groups is 13.2 mmol / m 2 .

[0206] The third modified silanized hollow ceramic fiber intermediate is subjected to activation treatment to obtain modified hollow ceramic fibers. The activator is a 4.5% (mass concentration) aqueous sodium hydroxide solution. The treatment conditions for the activator treatment are as follows: The aqueous sodium hydroxide solution is transported to the inner cavity of the hollow ceramic fiber through a conventional pump. The treatment temperature is 35°C, the linear velocity is 0.15 m / s, and the treatment time is 2.2 hours. Subsequently, demineralized water is transported to the inner cavity of the hollow ceramic fiber through a conventional pump, the linear velocity is 0.13 m / s, and the treatment temperature is 45°C.

[0207] In this example, the feed volume space velocity of the dry gas raw material is 800 h -1 , and the cross-sectional arrangement density of the ceramic fibers in the hollow ceramic fiber regular module is 40,000 roots / m 2 . When the dry gas passes through the inner cavity of the ceramic fiber, the adsorption temperature is 25°C, and the adsorption pressure (gauge pressure) is 600 kPa. The regenerant includes diethanolamine, N-methyldiethanolamine, potassium carbonate, and demineralized water. In terms of the mass composition percentage of the regenerant solution, N-methyldiethanolamine is 25%, diethanolamine is 3.5%, potassium carbonate is 3.5%, and the rest is demineralized water. The regeneration conditions are as follows: The temperature is 25°C, the pressure difference relative to the raw material dry gas (the difference between the regenerant liquid pressure and the raw material dry gas pressure) is -90 kPa, and the feed volume ratio of the dry gas raw material to the regenerant solution is 550 by volume.

[0208] The degumming powder tower in this example is a conventional packed tower, with 2 theoretical plates, an operating temperature of 25°C, the degumming powder is fresh water, and the gas-water ratio is 56. The dry gas filter is a conventional bag filter, with a separation accuracy of 4 microns.

[0209] The cyclone separator in this example is a conventional liquid separation device in the art, with a separation accuracy of 200 microns.

[0210] The operating conditions of the desulfurized and purified dry gas in the water wash tower are as follows: The temperature is 45°C, the pressure is 600 kPa by gauge pressure, the water is demineralized water, and the water wash tower has 7 theoretical plates. The volume ratio of the desulfurized and purified dry gas to the demineralized water is 75 by volume.

[0211] The depropylenating agent is a conventional depropylenating agent in the art, preferably benzene. The conditions for the raw material dry gas to contact the depropylenating agent are as follows: The temperature is 22°C, the pressure is 800 kPa by gauge pressure, and the depropylenating contact tower has 9 theoretical plates. The volume ratio of the raw material dry gas to the depropylenating agent is 85 by volume.

[0212] The total sulfur volume content in the depropylenated and purified dry gas obtained in this example is 7.3 ppm.

[0213]

Comparative Example 1

[0214] This comparative example, compared with Example 3, lies in directly using a commercially available hollow ceramic fiber with an inner diameter of 0.9 mm, an outer diameter of 1.9 mm, a pore diameter of the fiber membrane wall of 950 nm, a porosity of 52%, and a material of silica. The dry gas raw material used in this comparative example is the same as that in Example 3, and the separation process for the dry gas raw material is the same as that in Example 3.

[0215] The total sulfur volume content in the purified dry gas after propylene removal is 917 ppm.

[0216]

Comparative Example 2

[0217] This comparative example, compared with Example 3, only lies in that the desulfurization uses a packed tower (packing model 250Y, porosity of 98%) for water washing to remove sulfurous impurities. The equipment and process operating conditions of the water washing tower are as follows: the temperature is 35°C, the pressure (gauge pressure) is 1000 kPa, the number of theoretical plates is 19, a 30% aqueous solution of diethanolamine by mass concentration is used, and the gas-liquid volume ratio is 37.

[0218] The total sulfur volume content in the purified dry gas after propylene removal is 2900 ppm.

[0219]

Comparative Example 3

[0220] This comparative example uses commercial 201×7OH resin as the adsorbent and adopts a conventional fixed bed adsorption process. The adsorption conditions are as follows: the resin filling amount is 50 cubic meters, the adsorption temperature is 30°C, and the volume space velocity is 30 h -1 .

[0221] The dry gas raw material is the same as that in Example 3. In the initial stage of operation, the total sulfur content in the purified dry gas after propylene removal is 3 ppm. The adsorbent breaks through in about 7 minutes, and regeneration needs to use 4% - 6% sodium hydroxide for regeneration. The consumption volume of the regeneration liquid per unit volume of the adsorbent is 4 - 5 times.

[0222] The specific embodiments of the present invention have been described in detail above. However, the present invention is not limited thereto. Within the scope of the technical concept of the present invention, various simple modifications can be made to the technical solutions of the present invention, including any other suitable combination of each technical feature. These simple modifications and combinations should also be regarded as the content disclosed by the present invention and fall within the protection scope of the present invention.

Claims

1. A modified hollow ceramic fiber, wherein, The modified hollow ceramic fiber includes a hollow ceramic fiber, and the inner surface of the hollow ceramic fiber includes a silane layer, a first modified layer, and a second modified layer from outside to inside; the first modified layer contains phenyl; the second modified layer contains secondary amino groups and primary amino groups; The inner surface of the hollow ceramic fiber includes a silane layer, a first modified layer, and a second modified layer from outside to inside, which means that the silane layer is on the inner surface of the hollow ceramic fiber, the first modified layer is on the inner surface of the silane layer, and the second modified layer is on the inner surface of the first modified layer; In the silane layer, the molar ratio of the siloxyl group to the silicon-carbon group is 0.6 to 1.0; In the first modified layer, the phenyl content is 0.13 to 0.29 mol / m 2 ; In the second modified layer, the content of secondary amino groups is 0.30 to 0.50 mol / m 2 , and the content of primary amino groups is 0.09 to 0.22 mol / m 2 .

2. The modified hollow ceramic fiber according to claim 1, wherein The thickness of the silane layer is 10 to 30 microns.

3. The modified hollow ceramic fiber according to claim 1, wherein The thickness of the first modified layer is 3 to 6 microns.

4. The modified hollow ceramic fiber according to claim 1, wherein The second modified layer also contains tertiary amino groups, and the content of the tertiary amino groups is 0.07 to 0.14 mol / m 2 .

5. The modified hollow ceramic fiber according to claim 1, wherein, The inner diameter of the hollow ceramic fiber is 0.3 to 1.0 mm, the outer diameter is 1.3 to 2.0 mm, the pore diameter of the fiber membrane wall is 500 to 1000 nm, and the porosity is 50% to 70%.

6. The modified hollow ceramic fiber according to claim 5, wherein The material of the hollow ceramic fiber is silica or alumina.

7. The modified hollow ceramic fiber according to claim 1, wherein The inner surface of the second modified layer further includes a third modified layer; in the third modified layer, the content of secondary amino groups is 8-30 mmol / m 2 , the content of imino groups is 3.4-12.9 mmol / m 2 , and the content of methoxy groups is 9.6-39.0 mmol / m 2 .

8. The preparation method of the modified hollow ceramic fiber according to any one of claims 1-6, comprising: (1) The hollow ceramic fiber is subjected to silanization treatment to obtain a silanized hollow ceramic fiber; (2) The silanized hollow ceramic fiber obtained in step (1) is subjected to a first modification treatment; (3) The hollow ceramic fiber obtained in step (2) is subjected to a second modification treatment; (4) The hollow ceramic fiber obtained in step (3) is subjected to activation treatment to obtain a modified hollow ceramic fiber.

9. The preparation method according to claim 8, characterized in that, The silanization reagent used in step (1) for silanization is selected from at least one of γ-methacryloxypropylmethyldiethoxysilane and γ-methacryloxypropylmethyldimethoxysilane.

10. The preparation method according to claim 8, characterized in that, The first modifier used in the first modification treatment in step (2) is a first modification component, benzoyl peroxide, and a solvent; the first modification component is selected from at least one of 3-(3,5-dichlorophenyl)-1-propene, 1-(3-buten-1-yl)-2,4-dichlorobenzene, and 3-(3,4-dichlorophenyl)-1-propene; the solvent is selected from at least one of toluene, p-xylene, m-xylene, and o-xylene.

11. The preparation method according to claim 10, characterized in that, The first modification component in the first modifier used in the first modification treatment in step (2) is 1-(3-buten-1-yl)-2,4-dichlorobenzene.

12. The preparation method according to claim 10, characterized in that, In step (2), by mass, the first modification component: benzoyl peroxide: solvent = (15 to 25): (1 to 3): (100 to 200).

13. The preparation method according to claim 10, characterized in that, The treatment conditions of the first modification treatment in step (2) are as follows: controlling the fluid linear velocity of the first modifier on the inner surface of the silanized hollow ceramic fiber membrane obtained in step (1) to be 0.4 to 0.8 m / s, the treatment temperature to be 30°C to 60°C, and the treatment time to be 2 to 4 hours.

14. The preparation method according to claim 8, characterized in that, The second modifier used in the second modification treatment in step (3) is a second modification component, polyoxyethylene polyoxypropylene ether, a catalyst, and a solvent; the catalyst is selected from one of Lewis acids or Lewis bases; the second modification component is selected from at least one of N1-(2-aminoethyl)-N1-(2-aminophenyl)-1,2-benzenediamine, N,N-bis(4-aminophenyl)-1,4-benzenediamine, and 3,5-diamino-N-(4-aminophenyl)benzamide; the solvent is selected from at least one of toluene, p-xylene, m-xylene, and o-xylene.

15. The preparation method according to claim 14, characterized in that, The second modification component of the second modifier used in the second modification treatment is N,N-bis(4-aminophenyl)-1,4-benzenediamine, and the catalyst is at least one of anhydrous zinc chloride, anhydrous stannic chloride, and anhydrous aluminum chloride.

16. The preparation method according to claim 14, characterized in that, In step (3), by mass parts, the second modification component: polyoxyethylene polyoxypropylene ether: catalyst: solvent = (20-30):(2-6):(10-20):(200-300).

17. The preparation method according to claim 14, characterized in that, In step (3), the treatment conditions of the second modification treatment are as follows: controlling the fluid linear velocity of the second modifier on the inner surface of the silanized hollow ceramic fiber obtained in step (2) to be 0.6-1.4 m / s, the treatment temperature to be 55°C-75°C, the treatment time to be 2-4 hours, and the treatment pressure gauge pressure to be 300-600 kPa.

18. The preparation method according to claim 8, wherein, In step (3), after the second modification treatment of the hollow ceramic fibers obtained in step (2), a third modification treatment is carried out; the content of secondary amino groups introduced into the modified hollow ceramic fibers by the third modification treatment is 8-30 mmol / m 2 , the content of imino groups is 3.4-12.9 mmol / m 2 , and the content of methoxy groups is 9.6-39.0 mmol / m 2 .

19. The preparation method according to claim 18, characterized in that, In step (3), the third modifier used in the third modification treatment is a third modification component, a diluent, 3,5-dichloro-2-methoxyaniline, and a catalyst; the third modification component is selected from at least one of 2-[2-(2,6-dichlorophenyl)ethyl]hydrazinecarboxamidine, N-amidino-2-(2,6-dichlorophenyl)acetamide, and N1,N2-bis(4-chlorophenyl)acetamidine; the diluent is at least one of tetrahydrofuran, dichloromethane, dichloroethane, chloroform, and trichloroethane; the catalyst is selected from one of Lewis acids or Lewis bases.

20. The preparation method according to claim 19, characterized in that, The third modification component of the third modifier used in the third modification treatment in step (3) is N-amidino-2-(2,6-dichlorophenyl)acetamide, and the catalyst is at least one of anhydrous zinc chloride, anhydrous stannic chloride, and anhydrous aluminum chloride.

21. The preparation method according to claim 19, characterized in that, In step (3), by mass parts, the third modification component: diluent: 3,5-dichloro-2-methoxyaniline: catalyst = (10-20):(200-300):(40-80):(10-20).

22. The preparation method according to claim 19, characterized in that, In step (3), the third modification treatment adopts a flow treatment method, and the treatment conditions of the third modification treatment are as follows: controlling the fluid linear velocity of the third modifier on the inner surface of the silanized hollow ceramic fiber obtained in step (3) to be 1.5-3 m / s, the treatment temperature to be 60°C-75°C, the treatment time to be 6-8 hours, and the treatment pressure gauge pressure to be 300-500 kPa.

23. The preparation method according to claim 8 or 18, characterized in that, After the second modification treatment or the third modification treatment, a third post-modification treatment is carried out, and the pre-activator used in the third post-modification treatment is anhydrous ethanol.

24. The preparation method according to claim 23, wherein The third post-modification treatment conditions are as follows: The pre-activator is transported into the inner cavity of the hollow ceramic fiber, the temperature is 60°C to 80°C, the fluid linear velocity of the pre-activator on the inner surface of the hollow fiber membrane is controlled to be 0.3 to 0.7 m / s, the continuous treatment time is 1 to 3 hours, and after the third post-modification treatment, it is purged and dried with inert gas at 110°C to 130°C for 0.5 to 1.0 hour.

25. The preparation method according to claim 8 or 18, characterized in that, In step (4), the activator used in the activation treatment is an alkaline aqueous solution with a mass concentration of 2% to 10%; the alkaline aqueous solution is an inorganic base solution and / or an organic base solution; the treatment conditions of the activation treatment are as follows: The alkaline aqueous solution is transported into the inner cavity of the hollow ceramic fiber, the treatment temperature is 30°C to 50°C, the fluid linear velocity of the activator on the inner surface of the hollow fiber membrane is controlled to be 0.1 to 0.3 m / s, and the treatment time is 2 to 3 hours.

26. The preparation method according to claim 25, characterized in that, In step (4), the alkaline aqueous solution is at least one of sodium hydroxide aqueous solution and potassium hydroxide aqueous solution.

27. The preparation method according to claim 25, wherein In step (4), after the activation treatment, it is treated with demineralized water. In the demineralized water treatment, the demineralized water is transported into the inner cavity of the hollow ceramic fiber, the surface fluid linear velocity is 0.1 to 0.3 m / s, and the treatment temperature is 40°C to 60°C.

28. Use of the modified hollow ceramic fiber according to any one of claims 1-7 or the modified hollow ceramic fiber prepared by the preparation method according to any one of claims 8-27 in dry gas desulfurization impurities, wherein, The raw material dry gas contacts with the modified hollow ceramic fiber to obtain purified dry gas with desulfurized impurities.

29. The application according to claim 28, wherein, The application uses a desulfurization refiner, which is provided with a multi-layer integrated module of modified hollow ceramic fibers. The upper end of the desulfurization refiner is provided with a raw material dry gas inlet and an inlet dry gas distributor. The raw material dry gas inlet is connected to the inlet dry gas distributor, the inlet dry gas distributor is connected to the modified hollow ceramic fiber module, a dry gas redistributor is provided between adjacent modified hollow ceramic fiber modules, the lower end of the desulfurization refiner is provided with a purified dry gas collector pipe and a purified dry gas outlet, the purified dry gas collector pipe is connected to the purified dry gas outlet, and the modified hollow ceramic fiber module is connected to the purified dry gas collector pipe. Each modified hollow ceramic fiber module is provided with a regenerant inlet and a regenerant outlet. Among them, the raw material dry gas flows in the inner cavity of the modified hollow ceramic fiber, and the regenerant flows in the shell side of the modified hollow ceramic fiber module, realizing adsorption and regeneration simultaneously, so as to obtain purified dry gas and the regenerant after work.

30. The application according to claim 29, characterized in that, The regenerant is selected from at least one of diethanolamine, N-methyldiethanolamine, and potassium carbonate.

31. The application according to claim 30, wherein, In the regenerant solution, by mass composition percentage, N-methyldiethanolamine is 20% to 40%, diethanolamine is 3% to 5%, potassium carbonate is 3% to 5%, and the rest is demineralized water.

32. The application according to claim 30, characterized in that The regeneration conditions are as follows: the temperature is 20 to 50°C, the pressure difference relative to the raw material dry gas is -100 to -50 kPa, and the feed ratio of the dry gas raw material to the regenerant solution is 400 to 600 by volume.

33. The application according to claim 28, wherein In the raw material dry gas, the volume content based on the total sulfur element is not less than 500 ppm and not more than 150,000 ppm.

34. The application according to claim 33, wherein In the raw material dry gas, the volume content based on the total sulfur element is not less than 50,000 ppm.

35. The application according to claim 33, characterized in that, In the raw material dry gas, the volume content based on the total sulfur element is not less than 100,000 ppm.

36. The application according to claim 33, characterized in that, The volumetric hourly space velocity of the raw material dry gas feed is 500-1000 h -1 , the modified hollow ceramic fibers are packed in a regular module, and the cross-sectional arrangement density of the modified hollow ceramic fibers is 30,000-80,000 pieces / m 2 ; the operating conditions for desulfurization are as follows: the adsorption temperature is 20-50 °C, and the adsorption pressure gauge pressure is 500-1200 kPa.

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