Carbon molecular sieve as well as preparation method and application thereof

Abstract

The invention relates to a carbon molecular sieve as well as a preparation method and application thereof. The preparation method comprises the following steps: molding and drying a mixture containing solid phenolic resin powder, furfuryl ketone resin and water to obtain a prepared material; in the presence of shielding gas, carrying out carbonization treatment on the prepared material to obtain a carbonized material; activating the carbonized material by using an activating agent to obtain an activated material; and performing carbon deposition on the activated material by using a deposition reagent to obtain the carbon molecular sieve. According to the method, solid phenolic resin powder with the acidity value smaller than 7 and furfuryl ketone resin are used as main raw materials, and in the preparation process, the furfuryl ketone resin is cross-linked and cured and reacts with the solid phenolic resin powder to form a tightly-combined structure, so that the prepared carbon molecular sieve has high separation performance, meanwhile, the mechanical strength is obviously improved, and the service life of the carbon molecular sieve is prolonged. In pressure swing adsorption operation, the material is not easy to break and long in service life.

Description

Technical Field

[0001] The present application relates to the technical field of carbon molecular sieve preparation, and in particular to a carbon molecular sieve and a preparation method and application thereof. Background Art

[0002] Carbon molecular sieves, also known as carbon molecular sieves, can separate gases by exploiting the differences in mass transfer rates between different gas components within their pores. Gases with high mass transfer rates quickly occupy adsorption sites, resulting in a high adsorption capacity; gases with low mass transfer rates are unable to occupy adsorption sites, resulting in a low adsorption capacity. This difference in dynamic adsorption capacity enables the separation of different gases.

[0003] The traditional method for preparing carbon molecular sieves involves grinding raw materials capable of producing gas separation properties into a powder and then mixing it with a binder to form a mold. While carbon molecular sieves produced using this traditional method have gas separation capabilities, they have low mechanical strength and are easily broken and pulverized during pressure swing adsorption operations. Summary of the Invention

[0004] Based on this, the present application provides a carbon molecular sieve and a preparation method and application thereof to improve the problem of low mechanical strength of the carbon molecular sieve.

[0005] The first aspect of the present application provides a method for preparing a carbon molecular sieve, the method comprising the following steps:

[0006] forming and drying a mixture comprising solid phenolic resin powder, furfural resin and water to obtain a pre-material;

[0007] In the presence of a protective gas, the prepared material is carbonized to obtain a carbonized material;

[0008] activating the carbonized material using an activator to obtain an activated material;

[0009] Using a deposition reagent to perform carbon deposition on the activated material to obtain a carbon molecular sieve;

[0010] Wherein, the acidity value of the solid phenolic resin powder is less than 7.

[0011] In some embodiments, the solid phenolic resin powder has an acidity of 1 to 3; and / or

[0012] The forming method is extrusion forming.

[0013] In some embodiments, the mass ratio of the furfural resin to the solid phenolic resin powder is 0.4-0.6:1; and / or

[0014] The mass ratio of the water to the solid phenolic resin powder is 0.5-0.7:1.

[0015] In some embodiments, the mixture further comprises at least one of sesbania powder and polyethylene glycol;

[0016] Optionally, the mass ratio of the sesbania powder to the solid phenolic resin powder is 0.03-0.2:1;

[0017] Optionally, the mass ratio of the polyethylene glycol to the solid phenolic resin powder is 0.01-0.2:1;

[0018] Optionally, the number average molecular weight of the polyethylene glycol is 2000-6000.

[0019] In some embodiments, the carbonization treatment conditions include: a temperature of 600° C. to 800° C., a time of 30 min to 90 min, and a heating rate of 5° C. / min to 10° C. / min; and / or

[0020] The protective gas includes at least one of an inert atmosphere and nitrogen.

[0021] In some embodiments, the step of activating the carbonized material using an activator includes:

[0022] activating the carbonized material using a first carrier gas carrying an activating agent;

[0023] Optionally, the activation treatment conditions include: an activation treatment temperature of 700° C. to 1000° C., an activation treatment time of 60 min to 150 min, and an activator flow rate of 0.3 mL / min to 0.5 mL / min.

[0024] Optionally, the activating agent is selected from at least one of water, carbon monoxide and oxygen.

[0025] In some embodiments, the step of carbon depositing the activated material using a deposition reagent comprises:

[0026] Using a second carrier gas to carry a deposition reagent to perform carbon deposition on the activated material;

[0027] Optionally, the carbon deposition conditions include: a carbon deposition temperature of 700° C. to 1000° C., a deposition reagent flow rate of 0.15 mL / min to 0.4 mL / min, and a carbon deposition time of 60 min to 150 min.

[0028] In some embodiments, the deposition agent is selected from at least one of benzene, toluene, xylene, and methane.

[0029] In a second aspect, the present application provides a carbon molecular sieve, which is prepared using the carbon sieve preparation method described above.

[0030] The third aspect of the present application provides the use of the carbon molecular sieve described above in gas separation.

[0031] This application has the following beneficial effects:

[0032] In the preparation method described in the present application, solid phenolic resin powder with an acidity value of less than 7 and furfural resin are used as the main raw materials. The furfural resin has a low viscosity and good fluidity. During the raw material mixing process, the solid phenolic resin powder and the furfural resin can be fully mixed. During the preparation process, the furfural resin is cross-linked and cured, and also reacts with the solid phenolic resin powder to form a tightly bound structure, so that the prepared carbon molecular sieve has higher separation performance while significantly improving the mechanical strength. It is not easy to break during pressure swing adsorption operation and has a long service life.

[0033] At the same time, furfural, the main raw material of furfural resin, is a chemical substance that can be produced from biomass such as corn cobs. It is renewable and reduces pollution to the environment. BRIEF DESCRIPTION OF THE DRAWINGS

[0034] In order to more clearly illustrate the technical solutions in the embodiments of the present application, the following briefly introduces the drawings required for use in the description of the embodiments. Obviously, the drawings described below are only some embodiments of the present application. For ordinary technicians in this field, other drawings can be obtained based on these drawings without any creative work.

[0035] Figure 1 The present invention is a flow chart of a method for preparing a carbon molecular sieve according to some embodiments of the present application.

[0036] Figure 2 The graphs show the results of thermogravimetric testing of solid phenolic resin powder, furfural resin, sesbania powder and polyethylene glycol in Test Example 1.

[0037] Figure 3 This is a graph showing the results of thermogravimetric testing of a mixture of solid phenolic resin powder, furfural resin, sesbania powder, and polyethylene glycol in Test Example 2.

[0038] Figure 4 Schematic diagram of the double-tower pressure swing adsorption device used in Test Example 2.

[0039] Description of reference numerals:

[0040] 1-first adsorption column; 2-second adsorption column; 3-solenoid valve; 4-pressure reducing valve; 5-mass flowmeter; 6-check valve; 7-buffer tank; 8-needle valve; 9-rotor flowmeter; 10-wet flowmeter; 11-pressure gauge. DETAILED DESCRIPTION

[0041] To facilitate understanding of the present application, the present application will be described more fully below in conjunction with the specific embodiments. Preferred embodiments of the present application are provided in the specific embodiments. However, the present application can be implemented in many different forms and is not limited to the embodiments described herein. On the contrary, the purpose of providing these embodiments is to make the understanding of the disclosure of the present application more thorough and comprehensive.

[0042] Unless otherwise defined, all technical and scientific terms used herein have the same meaning as commonly understood by those skilled in the art to which this application pertains. The terms used herein in the specification of this application are for the purpose of describing specific embodiments only and are not intended to limit this application. The term "and / or" as used herein includes any and all combinations of one or more of the associated listed items.

[0043] Unless otherwise specified or incompatible therewith, terms and phrases used in this application shall have the following meanings:

[0044] In this application, the terms "first" and "second" are used for descriptive purposes only and should not be understood to indicate or imply relative importance or implicitly specify the number of technical features indicated. Therefore, a feature specified as "first" or "second" may explicitly or implicitly include at least one of the features.

[0045] In this application, the terms "further," "further," "particularly," "for example," "such as," "example," and "for example" are used for descriptive purposes to indicate that the preceding and following technical solutions are related in terms of their coverage, but should not be construed as limiting the preceding technical solution or the scope of protection of this document. In this document, unless otherwise specified, "A (such as B)" means that B is a non-limiting example of A, and it is understood that A is not limited to B.

[0046] In this application, "optionally", "optional", and "optional" mean optional, that is, any one of the two parallel options of "with" or "without". If multiple "optional" appear in a technical solution, unless otherwise specified and there is no contradiction or mutual restriction, each "optional" is independent. In this application, descriptions such as "optionally contain" and "optionally include" mean "containing or not containing". "Optional component X" means the presence or absence of component X, or means containing or not containing component X.

[0047] When a numerical range is disclosed in this application, the range is considered continuous and includes the minimum and maximum values of the range, as well as every value between such minimum and maximum values. Further, when a range refers to an integer, every integer between the minimum and maximum values of the range is included. In addition, when multiple ranges are provided to describe a feature or characteristic, the ranges can be combined. In other words, unless otherwise indicated, all ranges disclosed in this application should be understood to include any and all subranges subsumed therein.

[0048] In this application, the technical features described in an open manner include closed technical solutions composed of the listed features, and also include open technical solutions containing the listed features.

[0049] The terms "including," "having," and any variations thereof in the embodiments of the present application are intended to cover non-exclusive inclusions. For example, a process, method, system, product, or apparatus comprising a series of steps or units is not limited to the listed steps or units but may optionally include steps or units not listed, or may optionally include other steps or components inherent to the process, method, product, or apparatus.

[0050] References to "embodiments" in this application mean that a particular feature, structure, or characteristic described in connection with the embodiment may be included in at least one embodiment of the application. The appearance of this phrase in various places in the specification does not necessarily refer to the same embodiment, nor does it constitute an independent or alternative embodiment that is mutually exclusive of other embodiments. It is understood, both explicitly and implicitly, by those skilled in the art that the embodiments described in this application may be combined with other embodiments.

[0051] In the flowchart of the present application, although the various steps are displayed in sequence as indicated by the arrows, these steps are not necessarily performed in the order indicated by the arrows. Unless otherwise specified in the text, there is no strict order restriction for the execution of these steps, and they can be performed in other orders. Moreover, at least part of the steps in the figure may include multiple sub-steps or multiple stages. These sub-steps or stages are not necessarily performed at the same time, but can be performed at different times. Their execution order is not necessarily sequential, but can be performed in turn or alternately with other steps or at least part of other sub-steps or stages.

[0052] The traditional carbon molecular sieve preparation process is to grind the raw materials that can produce pores with gas separation capabilities into powder and then mix them with a binder to form carbon molecular sieve particles. Although they have the ability to separate gases, they have the disadvantage of low mechanical strength and are easily broken and pulverized during pressure swing adsorption operations, resulting in a short service life.

[0053] Based on this, the first aspect of the present application provides a method for preparing a carbon molecular sieve, Figure 1 , the preparation method comprises the following steps:

[0054] S1: forming and drying a mixture comprising solid phenolic resin powder, furfural resin and water to obtain a pre-mixed material;

[0055] S2: in the presence of a protective gas, carbonizing the prepared material to obtain a carbonized material;

[0056] S3: activating the carbonized material using an activating agent to obtain an activated material;

[0057] S4: using a deposition reagent to perform carbon deposition on the activated material to obtain a carbon molecular sieve;

[0058] Wherein, the acidity value of the solid phenolic resin powder is less than 7.

[0059] Solid phenolic resin can be produced from liquid thermoplastic phenolic resin or thermosetting phenolic resin. Traditional production processes use acidic curing agents (such as benzenesulfonic acid, phenolsulfonic acid, and p-toluenesulfonic acid) or alkaline curing agents. When acidic curing agents are used, the resulting solid phenolic resin may contain residual acidic substances or acidic groups. During their research, the inventors of this application unexpectedly discovered that solid phenolic resin powder with an acidity value of less than 7 can cause furfural resin to undergo cross-linking and curing without the addition of a curing agent.

[0060] Based on this, the present application creatively proposes a method for preparing a carbon molecular sieve, which involves molding and drying a mixture comprising a solid phenolic resin powder having an acidity value of less than 7 and a furfural resin, and then performing a carbonization treatment, an activation treatment, and carbon deposition. The furfural resin has a low viscosity and good fluidity, and the furfural resin and the solid phenolic resin powder in the mixture are in uniform contact. Then, during the molding, drying, carbonization treatment, activation treatment, and carbon deposition process, the furfural resin continues to crosslink and solidify in the presence of the solid phenolic resin, and reacts with the solid phenolic resin powder to form a tightly bound special structure, so that the product carbon molecular sieve has a higher air separation performance while having significantly improved mechanical strength.

[0061] In the traditional preparation process of carbon molecular sieve, raw materials that can produce gas separation capabilities are usually crushed into powder and then mixed with a binder to form a mold. Common binders include coal tar, asphalt or liquid phenolic resin. The components of coal tar are complex and vary with the production source, affecting product quality and causing environmental pollution. Liquid phenolic resin is not easy to store, and the substances such as free phenol and formaldehyde contained therein can cause harm to the environment and the health of operators. The preparation method of the above-mentioned carbon molecular sieve uses solid phenolic resin powder and furfural resin as the main raw materials, wherein furfural, the main raw material of furfural resin, is a chemical substance that can be produced from biomass such as corn cobs. It has the characteristics of being renewable and reduces pollution to the environment.

[0062] In some embodiments, the percentage of solid phenolic resin powder with a particle size less than 50 μm is ≥ 80 wt%. It is understood that the percentage of solid phenolic resin powder with a particle size less than 50 μm includes, but is not limited to, 80 wt%, 85 wt%, 90 wt%, 95 wt%, and 100 wt%. In some examples, the percentage may be within a range consisting of any two of these values as endpoints, the same below.

[0063] In this application, the acidity value of solid phenolic resin powder is used to provide feedback on the acidity of the solid phenolic resin powder. The acidity value can be tested as follows:

[0064] Solid phenolic resin powder and water are mixed in a mass ratio of 1:20, and then filtered. The pH value (25°C) of the filtered solution is detected using a pH meter. The measured pH value is the acidity value of the solid phenolic resin powder.

[0065] In some embodiments, the acidity value of the solid phenolic resin may be 1-6.

[0066] In some embodiments, the acidity value of the solid phenolic resin powder may be 1-3.

[0067] In some specific embodiments, the acidity value of the solid phenolic resin powder can be 1, 1.2, 1.5, 2, 2.5 or 3, or any value within a range consisting of any two of the above values as end points.

[0068] In some embodiments, the mass ratio of furfural resin to solid phenolic resin powder can be 0.2 to 1:1.

[0069] In some embodiments, the mass ratio of furfural resin to solid phenolic resin powder is 0.4 to 0.6: 1. For example, the mass ratio can be 0.4: 1, 0.45: 1, 0.5: 1, 0.55: 1, or 0.6: 1, or any value within a range consisting of any two of the above values as endpoints.

[0070] In some embodiments, the mass ratio of water to solid phenolic resin powder is 0.5 to 0.7: 1. For example, it can be 0.5: 1, 0.55: 1, 0.6: 1, 0.65: 1, or 0.7: 1, or any value within a range consisting of any two of the above values as endpoints.

[0071] In some embodiments, the mixed material may be formed by extrusion, which may be performed using an extruder commonly used in the art.

[0072] In some embodiments, the mixture further comprises an extrusion aid, which can make the extrusion molding process smoother, thereby improving production efficiency and molding quality. In some specific embodiments, the mixture further comprises at least one of sesbania powder and polyethylene glycol. The addition of sesbania powder and polyethylene glycol imparts good lubricity to the mixture, which, when used in combination with a low-viscosity furfural resin, can make the extrusion process smoother. Furthermore, sesbania powder and polyethylene glycol can generate a pore structure during the carbonization process, thereby improving the performance of the carbon molecular sieve.

[0073] In some embodiments, the mass ratio of sesbania powder to solid phenolic resin powder is 0.03 to 0.2: 1. For example, the mass ratio can be 0.03: 1, 0.05: 1, 0.08: 1, 0.1: 1, 0.12: 1, 0.15: 1, 0.18: 1, or 0.2: 1, or any value within a range consisting of any two of the above values as endpoints.

[0074] In some embodiments, the mass ratio of polyethylene glycol to solid phenolic resin powder is 0.01-0.2:1. Exemplarily, it can be 0.01:1, 0.02:1, 0.05:1, 0.06:1, 0.08:1, 0.1:1, 0.12:1, 0.15:1, 0.18:1 or 0.2:1, or any value within the range formed by any two of the above point values as end values.

[0075] In some embodiments, the number average molecular weight of polyethylene glycol (PEG) is 2000-6000. For example, the polyethylene glycol can be PEG2000, PEG3000, PEG4000, PEG5000, or PEG6000, which can be purchased commercially.

[0076] In some embodiments, the mixture can be prepared according to the following process: solid phenolic resin powder, furfural resin, sesbania powder, polyethylene glycol and water are mixed to obtain a mixture.

[0077] In some embodiments, the drying conditions include: a drying temperature of 10° C. to 90° C., and a drying time of 5 h to 100 h.

[0078] In some embodiments, the drying conditions include: a drying temperature of 15° C. to 85° C., and a drying time of 6 h to 96 h.

[0079] In some embodiments, during the extrusion and drying of the mixed material, the furfural resin undergoes crosslinking and solidification, reacting with the solid phenolic resin to achieve initial shaping. The resulting dried material possesses a certain strength, which not only allows it to withstand mechanical breaking to obtain a pre-formed material of the target particle length, but also maintains the stability of the material during subsequent operations in the converter. In some embodiments, the pre-formed material prepared in step S1 has a diameter of 1 mm to 2 mm, and a particle length of 2 mm to 5 mm.

[0080] In some embodiments, the carbonization treatment conditions include: a temperature of 600°C to 800°C, a time of 30 min to 90 min, and a heating rate of 5°C / min to 10°C / min. For example, the carbonization temperature may be 600°C, 650°C, 700°C, 750°C, or 800°C; the carbonization time may be 30 min, 40 min, 50 min, 60 min, 70 min, 80 min, or 90 min, and the heating rate to the carbonization temperature may be 5°C / min, 6°C / min, 7°C / min, 8°C / min, 9°C / min, or 10°C / min.

[0081] There are no special requirements for the selection of protective gas, and a protective gas commonly used in carbonization treatment in the art can be selected. In some embodiments, the protective gas includes at least one of an inert atmosphere and nitrogen, and the inert atmosphere can be a common inert atmosphere such as argon and helium.

[0082] In some embodiments, the step of activating the carbonized material using an activator includes:

[0083] The first carrier gas is used to carry the activating agent to activate the carbonized material.

[0084] In some embodiments, a first carrier gas carrying an activating agent is used to activate the carbonized material. There are no specific requirements for the selection of the first carrier gas, and the first carrier gas may be provided by an inert atmosphere and / or nitrogen commonly used in the art. The inert atmosphere may be a common inert atmosphere such as argon or helium. In some embodiments, the flow rate of the first carrier gas may be 150 mL / min to 300 mL / min.

[0085] In some embodiments, the activation treatment conditions include: an activation treatment temperature of 700° C. to 1000° C., an activation treatment time of 60 min to 150 min, and an activator flow rate of 0.3 mL / min to 0.5 mL / min. For example, the activation treatment temperature may be 700° C., 800° C., 900° C., or 1000° C., the activation treatment time may be 60 min, 70 min, 80 min, 90 min, 100 min, 110 min, 120 min, 130 min, 140 min, or 150 min, and the activator flow rate may be 0.3 mL / min, 0.4 mL / min, or 0.5 mL / min.

[0086] In some embodiments, the activating agent is selected from at least one of water, carbon monoxide, and oxygen.

[0087] In some embodiments, the step of carbon depositing the activated material using a deposition reagent comprises:

[0088] Using a second carrier gas to carry a deposition reagent to perform carbon deposition on the activated material;

[0089] In some embodiments, a second carrier gas is used to carry the deposition reagent to carbon deposit the activated material. The choice of the second carrier gas is not particularly limited and can be provided by an inert atmosphere and / or nitrogen commonly used in the art. The inert atmosphere can be argon, helium, or other common inert atmospheres. In some embodiments, the flow rate of the second carrier gas can be 150 mL / min to 300 mL / min.

[0090] In some embodiments, the deposition agent may be a vapor deposition agent, and the pores are adjusted by vapor-phase carbon deposition on the activated material using the vapor deposition agent. In some embodiments, the deposition agent may be selected from at least one of benzene, toluene, xylene, and methane.

[0091] In some embodiments, the carbon deposition conditions include: a carbon deposition temperature of 700° C. to 1000° C., a deposition reagent flow rate of 0.15 mL / min to 0.4 mL / min, and a carbon deposition time of 60 min to 150 min. For example, the carbon deposition temperature may be 700° C., 800° C., 900° C., or 1000° C., the carbon deposition time may be 60 min, 70 min, 80 min, 90 min, 100 min, 110 min, 12 min, 130 min, 140 min, or 150 min, and the deposition reagent flow rate may be 0.15 mL / min, 0.2 mL / min, 0.25 mL / min, 0.3 mL / min, 0.35 mL / min, or 0.4 mL / min.

[0092] In some embodiments, steps S2, S3, and S4 can be performed continuously in a converter without repeated heating and cooling, which helps save energy and reduce production costs. Furthermore, the preformed material is transferred to the converter and steps S2-S4 are continued. During this time, the furfural resin continues to crosslink and solidify and reacts with the solid phenolic resin powder, thereby improving the mechanical strength of the carbon molecular sieve.

[0093] In a second aspect, the present application provides a carbon molecular sieve, which is prepared by the carbon molecule preparation method described above.

[0094] The carbon molecular sieve prepared by the above-mentioned carbon molecular sieve preparation method has both excellent separation performance and mechanical strength, and can be used for gas separation, including but not limited to air separation, for example, to produce nitrogen, and is not easy to pulverize during use, and has the advantage of a long service life.

[0095] The third aspect of the present application provides the application of the carbon molecular sieve described above in gas separation, including but not limited to the application in separating air to produce nitrogen, that is, a method for separating air to produce nitrogen is provided, and the carbon molecular sieve used includes the carbon molecular sieve prepared by the above-mentioned preparation method of the present application.

[0096] In some embodiments, the method for separating air to produce nitrogen mainly includes the following steps:

[0097] Air compression and pretreatment: compress and pretreat the air to obtain compressed air;

[0098] Adsorption stage: Compressed air enters an adsorption tower equipped with carbon molecular sieves for adsorption treatment. During this process, small molecules such as oxygen, carbon dioxide and water vapor are adsorbed by the carbon molecular sieves, and nitrogen is discharged from the top of the tower as a non-adsorbed gas.

[0099] Desorption stage: After the carbon molecular sieve is saturated with adsorption, the pressure in the adsorption tower is reduced to release the adsorbed gas and achieve regeneration of the carbon molecular sieve.

[0100] In the above-mentioned method of separating air to produce nitrogen, the carbon molecular sieve adsorbs oxygen and other small molecules in the compressed air in the tower without adsorbing nitrogen. After the adsorption reaches saturation, the pressure in the tower is reduced and the adsorbed gas is released. The carbon molecular sieve prepared by the above-mentioned preparation method of the present application has both excellent gas separation ability and high mechanical strength, and can remain stable during pressure changes. Based on this, through the above-mentioned "adsorption-desorption" cycle operation, continuous and efficient extraction of nitrogen from the air can be achieved.

[0101] In order to make the purpose and advantages of this application clearer, the preparation method of the carbon molecular sieve of this application and its effects are further described in detail below in conjunction with specific examples. It should be understood that the specific examples described here are only used to explain this application and shall not be used to limit this application. The following examples do not include other components except unavoidable impurities unless otherwise specified. The drugs and instruments used in the examples are all conventional choices in the art unless otherwise specified. The experimental methods for which specific conditions are not specified in the examples are implemented according to conventional conditions, such as the conditions described in the literature, books, or methods recommended by the manufacturer.

[0102] Example 1

[0103] S1: Selecting solid phenolic resin as a raw material, crushing and ball-milling the raw material to obtain solid phenolic resin powder, wherein the solid phenolic resin powder has a particle size of less than 50 μm, accounting for 80 wt %, and the acidity of the solid phenolic resin powder is 2 after testing; uniformly mixing the solid phenolic resin powder, furfural resin, sesbania powder, polyethylene glycol (number average molecular weight of 6000), and water in a mass ratio of 1:0.5:0.2:0.2:0.7 to obtain a mixture; extruding the mixture into strips, then drying it at 20° C. for 96 hours, and mechanically cutting the strips to obtain a pre-material with a diameter of 1 mm to 2 mm and a particle length of 2 mm to 5 mm;

[0104] S2: placing the prepared material into a converter and carbonizing it with nitrogen as a protective gas to obtain a carbonized material; wherein the nitrogen flow rate is 200 mL / min, the carbonization temperature is 800°C, the carbonization time is 30 min, and the heating rate is controlled at 10°C / min;

[0105] S3: Using nitrogen as a carrier gas to carry activator water into the converter to activate the carbonized material to obtain an activated material; wherein the nitrogen flow rate is 200 mL / min, the activation treatment temperature is 830°C, the activator flow rate is 0.35 ml / min, and the activation treatment time is 100 min;

[0106] S4: Using nitrogen as a carrier gas, benzene is carried into the converter to perform carbon deposition on the activated material. The carbon deposition temperature is controlled at 750°C, the carbon deposition time is 105 minutes, the benzene flow rate is 0.25 mL / min, and the nitrogen flow rate is 200 mL / min. After the carbon deposition is completed, it is cooled to room temperature under a nitrogen atmosphere to obtain a carbon molecular sieve.

[0107] Example 2

[0108] S1: Selecting solid phenolic resin as a raw material, crushing and ball-milling the raw material to obtain solid phenolic resin powder, wherein the particle size of the solid phenolic resin powder is less than 50 μm, and the acidity value of the solid phenolic resin powder is 2 after testing; uniformly mixing the solid phenolic resin powder, furfural resin, sesbania powder, polyethylene glycol (average molecular weight of 6000), and water in a mass ratio of 1:0.4:0.03:0.01:0.5 to obtain a mixture; extruding the mixture into strips, then drying it at 85° C. for 6 hours, and mechanically cutting the strips to obtain a pre-material with a diameter of 1 mm to 2 mm and a particle length of 2 mm to 5 mm;

[0109] S2: placing the prepared material into a converter and carbonizing it with nitrogen as a protective gas to obtain a carbonized material; wherein the nitrogen flow rate is 300 mL / min, the carbonization temperature is 750°C, the carbonization time is 60 min, and the heating rate is controlled at 10°C / min;

[0110] S3: Using nitrogen as a carrier gas to carry activator water into the converter to activate the carbonized material to obtain an activated material; wherein the nitrogen flow rate is 300 mL / min, the activation treatment temperature is 800°C, the activator flow rate is 0.50 mL / min, and the activation treatment time is 90 min;

[0111] S4: Nitrogen is used as a carrier gas to carry benzene into the converter to perform carbon deposition on the activated material. The carbon deposition temperature is controlled at 700°C, the carbon deposition time is 150 min, the benzene flow rate is 0.15 mL / min, and the nitrogen flow rate is 300 ml / min. After the carbon deposition is completed, it is cooled to room temperature under a nitrogen atmosphere to obtain a carbon molecular sieve.

[0112] Example 3

[0113] S1: Selecting solid phenolic resin as a raw material, crushing and ball-milling the raw material to obtain solid phenolic resin powder, wherein the particle size of the solid phenolic resin powder is less than 50 μm, and the acidity value of the solid phenolic resin powder is 2 after testing; uniformly mixing the solid phenolic resin powder, furfural resin, sesbania powder, polyethylene glycol (average molecular weight of 4000), and water in a mass ratio of 1:0.6:0.1:0.05:0.6 to obtain a mixture; extruding the mixture into strips, and then drying it at 80° C. for 6 hours, and mechanically cutting it to obtain a pre-material with a diameter of 1 mm to 2 mm and a particle length of 2 mm to 5 mm;

[0114] S2: placing the prepared material into a converter, using nitrogen as a protective gas, and carbonizing the material to obtain a carbonized material; wherein the nitrogen flow rate is 150 mL / min, the carbonizing temperature is 800°C, the carbonizing time is 30 min, and the heating rate is controlled to be 5°C / min;

[0115] S3: Using nitrogen as a carrier gas to carry activator water into the converter to activate the carbonized material to obtain an activated material; wherein the nitrogen flow rate is 150 mL / min, the activation treatment temperature is 800°C, the activator flow rate is 0.35 mL / min, and the activation treatment time is 60 min;

[0116] S4: Nitrogen is used as a carrier gas to carry benzene into the converter to carbonize the activated material. The carbon deposition temperature is controlled at 780°C, the carbon deposition time is 70 min, the benzene flow rate is 0.35 mL / min, and the nitrogen flow rate is 150 mL / min. After the reaction is completed, it is cooled to room temperature under a nitrogen atmosphere to obtain a carbon molecular sieve.

[0117] Example 4

[0118] The method is basically the same as Example 1, except that the mass ratio of solid phenolic resin powder to furfural resin is adjusted to 1:0.3.

[0119] Example 5

[0120] The method is basically the same as Example 1, except that the mass ratio of solid phenolic resin powder to furfural resin is adjusted to 1:0.7.

[0121] Example 6

[0122] The method is basically the same as Example 1, except that the solid phenolic resin powder with an acidity value of 5 is used instead of the solid phenolic resin powder with an acidity value of 2.

[0123] Comparative Example 1

[0124] The method is basically the same as Example 1, except that the solid phenolic resin powder with an acidity value of 8 is used instead of the solid phenolic resin powder with an acidity value of 2.

[0125] The specific steps include:

[0126] Solid phenolic resin is selected as a raw material, and the raw material is crushed and ball-milled to obtain solid phenolic resin powder, wherein the solid phenolic resin powder has a particle size of less than 50 μm, accounting for 80 wt%, and the acidity value of the solid phenolic resin powder is 8 after testing; the solid phenolic resin powder, furfural resin, sesbania powder, polyethylene glycol (number average molecular weight of 6000) and water are uniformly mixed in a mass ratio of 1:0.5:0.2:0.2:0.7 to obtain a mixture; and the mixture is extruded and dried.

[0127] During the experiment, it was found that the material obtained after extrusion molding and drying had low mechanical strength and could not maintain the particle shape under the action of external force, so the subsequent steps could not be carried out.

[0128] Test Example 1

[0129] The solid phenolic resin powder, furfural resin, sesbania powder and polyethylene glycol used in Example 1 were subjected to thermogravimetric tests respectively. The results are as follows: Figure 2 The solid phenolic resin powder, furfural resin, sesbania powder and polyethylene glycol used in Example 1 were mixed in a mass ratio of 1:0.5:0.033:0.016 and then subjected to thermogravimetric testing. The results are shown in FIG. Figure 3 shown.

[0130] Combine Figure 2 and Figure 3 Compared with the theoretical thermogravimetric curve obtained by fitting independent thermogravimetric data, the actual thermogravimetric curve results show a significant increase in the carbon residue rate of the raw material particles, especially a significant decrease in the weight loss range of 150°C to 300°C. This may be due to the cross-linking reaction of the furfural resin under the catalysis of the acidic groups or acidic substances contained in the solid phenolic resin powder, which inhibits the volatilization of its components and also causes cross-linking between the furfural resin and the solid phenolic resin powder.

[0131] Test Example 2

[0132] 1. The mechanical strength of the carbon molecular sieves prepared in each example and two commercial carbon molecular sieves (commercial carbon molecular sieve A and commercial carbon molecular sieve B) were tested. The results are shown in Table 1.

[0133] Among them, the mechanical strength of the carbon molecular sieve is measured by a YHKC-2A particle strength tester. A carbon molecular sieve with a particle length of 3 mm is selected to test its radial mechanical strength. The specific method is to place the carbon molecular sieve particles axially parallel to the horizontal direction on the test bench of the particle strength tester, and measure its radial mechanical strength by reading the maximum pressure that the particles can withstand before being crushed.

[0134] Table 1

[0135]

[0136] 2. The gas separation performance of the carbon molecular sieves prepared in each example, commercial carbon molecular sieve A and commercial carbon molecular sieve B were tested.

[0137] A small double-tower pressure swing adsorption device (such as Figure 4 Unlike industrial testing methods, the laboratory pressure swing adsorption device uses a set outlet flow rate to measure the product gas nitrogen concentration and the desorbed gas oxygen concentration, and calculates the nitrogen utilization rate as a criterion for evaluating carbon molecular sieves. Both the product gas nitrogen concentration and the desorbed gas oxygen concentration are volumetric concentrations. The product gas nitrogen concentration is primarily used for horizontal comparison and is related to gas production. The desorbed gas oxygen concentration reflects the micropore size and the ability to separate nitrogen and oxygen. The higher the value, the better. This indicator determines the nitrogen recovery rate and is one of the most critical and decisive indicators of carbon molecular sieves.

[0138] During the test, the raw gas enters the double-tower pressure swing adsorption device through an air compressor. The pressure entering the system is controlled to 0.5MPa by the pressure reducing valve 4, and the inlet flow is adjusted to 940mL / min by the mass flow meter 5. The adsorption and desorption behavior of the adsorption column is controlled by the solenoid valve 3. First, the first adsorption column 1 is pressurized for adsorption for 62s, while the second adsorption column 2 is desorbed. After the pressurization is completed, the first adsorption column 1 and the second adsorption column 2 are connected to equalize the pressure for 2s. Then the first adsorption column 1 is emptied and the second adsorption column 2 is pressurized. The first adsorption column 1 and the second adsorption column 2 complete an adsorption and desorption process, which is recorded as one cycle. Each experiment records 5 cycles after the device is stable. The product gas flow is recorded by the rotor flowmeter 9. The fixed flow rate of the product gas output is controlled by the needle valve 8 to be 150mL / min. The flow rate of the product gas is stabilized by the one-way valve 6 and the buffer tank 7. The desorbed gas volume is recorded by the wet flowmeter 10; the pressure gauge 11 monitors the gas pressure. The product gas and desorbed gas are detected by an oxygen analyzer, and the nitrogen concentration of the product gas and the oxygen concentration of the desorbed gas are obtained by calculation.

[0139] The calculation method of nitrogen utilization rate is:

[0140]

[0141] The test results are shown in Table 2.

[0142] Table 2

[0143]

[0144] From Table 1 and Table 2, it can be seen that the carbon molecular sieve prepared in the embodiment of the present application has excellent pressure swing adsorption air separation performance, and at the same time has great mechanical strength, is not easy to pulverize in pressure swing adsorption applications, and has a long service life.

[0145] The technical features of the above-mentioned embodiments can be combined arbitrarily. In order to make the description concise, not all possible combinations of the technical features in the above-mentioned embodiments are described. However, as long as there is no contradiction in the combination of these technical features, they should be considered to be within the scope of this specification.

[0146] The embodiments described above only express several implementation methods of the present application, which are convenient for understanding the technical solutions of the present application in a specific and detailed manner, but they cannot be understood as limiting the scope of protection of the invention patent. It should be pointed out that for ordinary technicians in this field, without departing from the concept of the present application, several variations and improvements can be made, which all fall within the scope of protection of the present application. It should be understood that the technical solutions obtained by those skilled in the art through logical analysis, reasoning or limited experiments on the basis of the technical solutions provided in the present application are all within the scope of protection of the claims attached to the present application. Therefore, the scope of protection of the patent of this application shall be based on the content of the attached claims, and the description and drawings can be used to interpret the content of the claims.

Claims

1. A method for preparing a carbon molecular sieve, characterized in that: The preparation method comprises the following steps: forming and drying a mixture comprising solid phenolic resin powder, furfural resin and water to obtain a pre-material; In the presence of a protective gas, the prepared material is carbonized to obtain a carbonized material; activating the carbonized material using an activator to obtain an activated material; Using a deposition reagent to perform carbon deposition on the activated material to obtain a carbon molecular sieve; Wherein, the acidity value of the solid phenolic resin powder is less than 7.

2. The preparation method according to claim 1, characterized in that The acidity of the solid phenolic resin powder is 1 to 3; and / or The forming method is extrusion forming.

3. The preparation method according to claim 1, characterized in that The mass ratio of the furfural resin to the solid phenolic resin powder is 0.4-0.6:1; and / or The mass ratio of the water to the solid phenolic resin powder is 0.5-0.7:

1.

4. The preparation method according to any one of claims 1 to 3, characterized in that The mixture further comprises at least one of sesbania powder and polyethylene glycol; Optionally, the mass ratio of the sesbania powder to the solid phenolic resin powder is 0.03-0.2:1; Optionally, the mass ratio of the polyethylene glycol to the solid phenolic resin powder is 0.01-0.2:1; Optionally, the number average molecular weight of the polyethylene glycol is 2000-6000.

5. The preparation method according to claim 1 or 2, characterized in that The carbonization treatment conditions include: temperature of 600°C to 800°C, time of 30 min to 90 min, and heating rate of 5°C / min to 10°C / min; and / or The protective gas includes at least one of an inert atmosphere and nitrogen.

6. The preparation method according to claim 1 or 2, characterized in that The step of activating the carbonized material using an activator comprises: activating the carbonized material using a first carrier gas carrying an activating agent; Optionally, the activation treatment conditions include: an activation treatment temperature of 700° C. to 1000° C., an activation treatment time of 60 min to 150 min, and an activator flow rate of 0.3 mL / min to 0.5 mL / min; Optionally, the activating agent is selected from at least one of water, carbon monoxide and oxygen.

7. The preparation method according to claim 1 or 2, characterized in that The step of using a deposition reagent to deposit carbon on the activated material comprises: Using a second carrier gas to carry a deposition reagent to perform carbon deposition on the activated material; Optionally, the carbon deposition conditions include: a carbon deposition temperature of 700° C. to 1000° C., a deposition reagent flow rate of 0.15 mL / min to 0.4 mL / min, and a carbon deposition time of 60 min to 150 min.

8. The preparation method according to claim 1, characterized in that The deposition agent is selected from at least one of benzene, toluene, xylene and methane.

9. A carbon molecular sieve, characterized in that The carbon molecular sieve is prepared by the preparation method of any one of claims 1 to 8.

10. Use of the carbon molecular sieve according to claim 9 in gas separation.

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