Adsorbent for nitrogen production and preparation method thereof

Abstract

The invention relates to an adsorbent for nitrogen production and a preparation method thereof, and belongs to the technical field of air nitrogen production. The technical problem to be solved by the invention is to provide a low-cost preparation method of the adsorbent for nitrogen production, and a carbon molecular sieve is modified by orthosilicate, so that the adsorbent has a very good adsorption effect. The method comprises the following steps: a, mixing and molding: mixing orthosilicate and phenolic resin, and extruding and molding into particles; and b, carbonizing: heating the particles obtained in the step a to 700-1000 DEG C under a protective atmosphere, and carbonizing to obtain the adsorbent for nitrogen production. The adsorbent for nitrogen production is prepared by mixing the orthosilicate and the phenolic resin, the method is simple, oxygen can be well adsorbed, nitrogen and oxygen can be well separated, the adsorbent can be used for preparing nitrogen through pressure swing adsorption, and the nitrogen production efficiency is high.

Description

Technical Field

[0001] The present invention relates to an adsorbent for nitrogen production and a preparation method thereof, belonging to the technical field of air nitrogen production. Background Art

[0002] As an inert gas, nitrogen is commonly used for the protection, transportation, sealing, etc. of flammable, explosive, corrosive, and oxidizable materials to ensure safe production. For example, in the production of reforming and hydrogenation units in petrochemical enterprises, nitrogen is required as a protective gas and displacement gas. To protect equipment, nitrogen is used as the sealing gas for some large units. In addition, nitrogen is also a crucial gas in chemical fiber production and can be used as a protective gas and transportation gas to prevent the oxidation of raw materials. It can be seen that the industrial demand for nitrogen is huge, and air contains a large amount of nitrogen. Generally, air separation method is used for nitrogen production.

[0003] Air separation for nitrogen production mainly includes cryogenic method, pressure swing adsorption method, membrane separation method, etc. Among them, pressure swing adsorption for nitrogen production has become the main nitrogen production method due to its low investment cost, high automation level, large operation flexibility, fast nitrogen production speed, and low nitrogen cost. Pressure swing adsorption nitrogen production technology mainly utilizes the differences in the adsorption capacity, adsorption rate, adsorption force, etc. of oxygen and nitrogen on the adsorbent and the characteristic that the adsorbent has different adsorption capacities for oxygen and nitrogen with different pressures to achieve oxygen-nitrogen separation. In this technology, the adsorbent is the key.

[0004] Currently, the adsorbent for nitrogen production is mainly carbon molecular sieve, and most traditional carbon molecular sieves are prepared by carbonization method. This method is to pretreat the raw materials, knead, form, and then sinter and carbonize in an inert atmosphere to obtain carbon molecular sieve. This method mainly utilizes the complex thermal decomposition reaction and thermal polymerization reaction of some unstable groups and bond bridges in the carbon-containing materials at high temperature, so that the pore size is expanded and tightened, and the pores of the carbonized product are expanded. The carbonization method for preparing carbon molecular sieve has a simple method and low cost, but has high requirements for raw materials, and mostly uses resin materials or materials with high volatile content such as coconut shell, hickory, and walnut shell. Moreover, the gas separation effect of the carbon molecular sieve prepared by the simple carbonization method is not good, and further activation or carbon deposition and other processes are required to improve the separation effect of the carbon molecular sieve.

[0005] The invention patent with the application number 201710294553.6 discloses a preparation method of carbon molecular sieve, which mixes rice husk with phenolic resin, polyvinyl alcohol and water to obtain a mixture; carbonizes the mixture under a protective gas to obtain a carbonized material; puts the carbonized material into an alkali solution for activation, washes with water, and dries to obtain an activated material; and performs carbon deposition pore filling treatment on the activated material with the vapor of a hydrocarbon compound carried by the protective gas to obtain carbon molecular sieve. Although this method can improve the adsorption effect, it requires carbon deposition pore filling treatment in the later stage of preparation, with a complex method and difficult to control, and high cost. Summary of the Invention

[0006] Aiming at the above defects, the technical problem solved by the present invention is to provide a preparation method of an adsorbent for nitrogen production with low cost. The carbon molecular sieve is modified by orthosilicate ester to make it have a good adsorption effect.

[0007] The preparation method of the adsorbent for nitrogen production of the present invention includes the following steps:

[0008] a. Mixing and forming: Mix orthosilicate ester and phenolic resin, and extrude and form them into particles.

[0009] b. Carbonization: Heat the particles obtained in step a to 700 - 1000 °C for carbonization under a protective atmosphere to obtain an adsorbent for nitrogen production.

[0010] In an embodiment of the present invention, in step a, the orthosilicate ester is methyl orthosilicate or ethyl orthosilicate.

[0011] In an embodiment of the present invention, in step a, the weight ratio of orthosilicate ester to phenolic resin is 0.1 - 0.7:1.

[0012] In a specific embodiment of the present invention, in step a, the weight ratio of orthosilicate ester to phenolic resin is 0.3:1.

[0013] In an embodiment of the present invention, in step a, the phenolic resin is in powder form with a particle size ≤ 10 μm.

[0014] In an embodiment of the present invention, in step b, the protective atmosphere is nitrogen or an inert atmosphere. The inert atmosphere includes but is not limited to helium, neon, argon, krypton, etc.

[0015] In an embodiment of the present invention, in step b, the carbonization time is 1 - 5 h.

[0016] In an embodiment of the present invention, in step b, heat to 800 °C for carbonization, and the carbonization time is 2 h.

[0017] The present invention also provides an adsorbent for nitrogen production prepared by the preparation method of the adsorbent for nitrogen production of the present invention.

[0018] The adsorbent for nitrogen production of the present invention is prepared by mixing orthosilicate ester and phenolic resin. Its method is simple, it can adsorb oxygen well, separate nitrogen and oxygen, and has a high nitrogen production efficiency.

[0019] The present invention also provides the application of the adsorbent for nitrogen production of the present invention in pressure swing adsorption air separation for nitrogen production.

[0020] The adsorbent for nitrogen production of the present invention can be used in pressure swing adsorption air separation for nitrogen production and has a high nitrogen production efficiency.

[0021] Compared with the prior art, the present invention has the following beneficial effects:

[0022] The adsorbent for nitrogen production of the present invention is prepared by mixing orthosilicate and phenolic resin. The method is simple, can well adsorb oxygen, separate nitrogen and oxygen, and can be used in pressure swing adsorption for nitrogen production with high nitrogen production efficiency. Specific embodiments

[0023] The preparation method of the adsorbent for nitrogen production of the present invention includes the following steps:

[0024] a. Mixing and forming: Mix orthosilicate and phenolic resin and extrude into particles.

[0025] b. Carbonization: Heat the particles obtained in step a to 700 - 1000 °C for carbonization in a protective atmosphere to obtain the adsorbent for nitrogen production.

[0026] Common orthosilicates in the art are applicable to the present invention. In one embodiment of the present invention, in step a, the orthosilicate is methyl orthosilicate or ethyl orthosilicate.

[0027] In one embodiment of the present invention, in step a, the weight ratio of orthosilicate to phenolic resin is 0.1 - 0.7:1.

[0028] In a specific embodiment of the present invention, in step a, the weight ratio of orthosilicate to phenolic resin is 0.3:1.

[0029] In one embodiment of the present invention, in step a, the phenolic resin is in powder form with a particle size ≤ 10 μm.

[0030] The protective atmosphere described in the present invention is an atmosphere that does not participate in the reaction. In one embodiment of the present invention, in step b, the protective atmosphere is nitrogen or an inert atmosphere. The inert atmosphere includes but is not limited to helium, neon, argon, krypton, etc.

[0031] In one embodiment of the present invention, in step b, the carbonization time is 1 - 5 h.

[0032] In one embodiment of the present invention, in step b, heat to 800 °C for carbonization with a carbonization time of 2 h.

[0033] The adsorbent for nitrogen production of the present invention is prepared by mixing orthosilicate and phenolic resin. The method is simple, can well adsorb oxygen, separate nitrogen and oxygen, and has high nitrogen production efficiency.

[0034] The adsorbent for nitrogen production of the present invention can be used in pressure swing adsorption of air for nitrogen production with high nitrogen production efficiency.

[0035] The following further describes the specific implementation manners of the present invention in conjunction with embodiments, and the present invention is not limited to the scope of the described embodiments

[0036] Examples 1 - 3

[0037] The adsorbent for nitrogen production is prepared according to the following method:

[0038] a. Mixing and molding: Mix orthosilicate with phenolic resin and extrude into particles; the orthosilicate is methyl orthosilicate, and the weight ratio of orthosilicate to phenolic resin is shown in Table 1, and the particle size of the phenolic resin ≤ 10 μm.

[0039] b. Carbonization: Heat and carbonize the particles obtained in step a under a nitrogen atmosphere to obtain the adsorbent for nitrogen production.

[0040] Table 1

[0041] Number Type of orthosilicate Weight ratio of orthosilicate to phenolic resin Carbonization temperature (°C) Carbonization time (h) Example 1 Methyl orthosilicate 0.3:1 800 2 Example 2 Methyl orthosilicate 0.3:1 700 4 Example 3 Ethyl orthosilicate 0.3:1 1000 1 Example 4 Ethyl orthosilicate 0.3:1 900 2

[0042] Comparative Example 1 (comparative experiment without adding orthosilicate)

[0043] The adsorbent for nitrogen production is prepared according to the following method:

[0044] a. Mixing and molding: Extrude phenolic resin into particles; the particle size of the phenolic resin ≤ 10 μm.

[0045] b. Carbonization: Heat and carbonize the particles obtained in step a under a nitrogen atmosphere to obtain molecular sieve.

[0046] Measure the performance of the adsorbent for nitrogen production prepared in the above examples, and the results are shown in Table 2.

[0047] Table 2

[0048] Example number <![CDATA[Bulk specific gravity, kg / m 3 > Nitrogen concentration, % <![CDATA[Production nitrogen volume, m 3 / h.t]]> Air-nitrogen ratio, % Example 1 630 99.5 235 3.2 Example 2 630 99.5 230 3.2 Example 3 630 99.5 260 3.1 Example 4 630 99.5 250 3.1 Comparative example 1 630 99.5 200 3.1 CMS-Z220 630 99.5 220 3.1

[0049] Note: The above performances are all measured under an adsorption pressure of 0.8 MPa, and the adsorption cycle is 1 × 50 s.

[0050] It can be seen that for the present invention, the adsorbent prepared by mixing orthosilicate and phenolic resin can well adsorb oxygen, separate nitrogen and oxygen, has a high nitrogen production amount and a high nitrogen production efficiency, and can be used in pressure swing adsorption for nitrogen production.

Claims

1. Preparation method of adsorbent for nitrogen production, characterized in that, It includes the following steps: a. Mixing and forming: Mix orthosilicate ester and phenolic resin, and extrude and form them into particles; b. Carbonization: Heat the particles obtained in step a to 700 - 1000 °C for carbonization under a protective atmosphere to obtain the adsorbent for nitrogen production.

2. The preparation method of adsorbent for nitrogen production according to claim 1, characterized in that: In step a, the orthosilicate ester is methyl orthosilicate or ethyl orthosilicate.

3. The preparation method of adsorbent for nitrogen production according to claim 1, characterized in that: In step a, the weight ratio of orthosilicate ester to phenolic resin is 0.1 - 0.7:

1.

4. The preparation method of adsorbent for nitrogen production according to claim 3, characterized in that: In step a, the weight ratio of orthosilicate ester to phenolic resin is 0.3:

1.

5. The preparation method of adsorbent for nitrogen production according to claim 1, characterized in that: In step a, the phenolic resin is in powder form with a particle size ≤ 10 μm.

6. The preparation method of adsorbent for nitrogen production according to claim 1, characterized in that: In step b, the protective atmosphere is nitrogen or an inert atmosphere.

7. The preparation method of adsorbent for nitrogen production according to claim 1, characterized in that: In step b, the carbonization time is 1 - 5 h.

8. The preparation method of adsorbent for nitrogen production according to claim 1, characterized in that: In step b, heat to 800 °C for carbonization, and the carbonization time is 2 h.

9. Adsorbent for nitrogen production prepared by the preparation method of adsorbent for nitrogen production according to any one of claims 1 to 8.